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ARHGEF7 ({beta}-PIX) Is Required for the Maintenance of Podocyte Architecture and Glomerular Function

Background

Previous studies showed that Cdc42, a member of the prototypical Rho family of small GTPases and a regulator of the actin cytoskeleton, is critical for the normal development and health of podocytes. However, upstream regulatory mechanisms for Cdc42 activity in podocytes are largely unknown.

Methods

We used a proximity-based ligation assay, BioID, to identify guanine nucleotide exchange factors that activate Cdc42 in immortalized human podocytes. We generated podocyte-specific ARHGEF7 (commonly known as β-PIX) knockout mice by crossing β-PIX floxed mice with Podocin-Cre mice. Using shRNA, we established cultured mouse podocytes with β-PIX knockdown and their controls.

Results

We identified β-PIX as a predominant guanine nucleotide exchange factor that interacts with Cdc42 in human podocytes. Podocyte-specific β-PIX knockout mice developed progressive proteinuria and kidney failure with global or segmental glomerulosclerosis in adulthood. Glomerular podocyte density gradually decreased in podocyte-specific β-PIX knockout mice, indicating podocyte loss. Compared with controls, glomeruli from podocyte-specific β-PIX knockout mice and cultured mouse podocytes with β-PIX knockdown exhibited significant reduction in Cdc42 activity. Loss of β-PIX promoted podocyte apoptosis, which was mediated by the reduced activity of the prosurvival transcriptional regulator Yes-associated protein.

Conclusions

These findings indicate that β-PIX is required for the maintenance of podocyte architecture and glomerular function via Cdc42 and its downstream Yes-associated protein activities. This appears to be the first evidence that a Rho–guanine nucleotide exchange factor plays a critical role in podocytes.




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Fructose Production and Metabolism in the Kidney

Understanding fructose metabolism might provide insights to renal pathophysiology. To support systemic glucose concentration, the proximal tubular cells reabsorb fructose as a substrate for gluconeogenesis. However, in instances when fructose intake is excessive, fructose metabolism is costly, resulting in energy depletion, uric acid generation, inflammation, and fibrosis in the kidney. A recent scientific advance is the discovery that fructose can be endogenously produced from glucose under pathologic conditions, not only in kidney diseases, but also in diabetes, in cardiac hypertrophy, and with dehydration. Why humans have such a deleterious mechanism to produce fructose is unknown, but it may relate to an evolutionary benefit in the past. In this article, we aim to illuminate the roles of fructose as it relates to gluconeogenesis and fructoneogenesis in the kidney.




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Probiotics for the Prevention of Ventilator-Associated Pneumonia: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND:Ventilator-associated pneumonia (VAP) is a common and serious complication of mechanical ventilation. We conducted a meta-analysis of published randomized controlled trials to evaluate the efficacy and safety of probiotics for VAP prevention in patients who received mechanical ventilation.METHODS:We searched a number of medical literature databases to identify randomized controlled trials that compared probiotics with controls for VAP prevention. The results were expressed as odds ratios (OR) or mean differences with accompanying 95% CIs. Study-level data were pooled by using a random-effects model. Data syntheses were accomplished by using statistical software.RESULTS:Fourteen studies that involved 1,975 subjects met our inclusion criteria. Probiotic administration was associated with a reduction in VAP incidence among all 13 studies included in the meta-analysis (OR 0.62, 95% CI 0.45–0.85; P = .003; I2 = 43%) but not among the 6 double-blinded studies (OR 0.72, 95% CI 0.44–1.19; P = .20; I2 = 55%). We found a shorter duration of antibiotic use for VAP (mean difference −1.44, 95% CI −2.88 to −0.01; P = .048, I2 = 30%) in the probiotics group than in the control group, and the finding comes from just 2 studies. No statistically significant differences were found between the groups in terms of ICU mortality (OR 0.95, 95% CI 0.67–1.34; P = .77; I2 = 0%), ICU stay (mean difference –0.77, 95% CI –2.58 to 1.04; P = .40; I2 = 43%), duration of mechanical ventilation (mean difference –0.91, 95% CI –2.20 to 0.38; P = .17; I2 = 25%), or occurrence of diarrhea (OR 0.72, 95% CI 0.45–1.15; P = .17; I2 = 41%).CONCLUSIONS:The meta-analysis results indicated that the administration of probiotics significantly reduced the incidence of VAP. Furthermore, our findings need to be verified in large-scale, well-designed, randomized, multi-center trials.




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Human Metapneumovirus Infection in Hospitalized Children

BACKGROUND:Most children are exposed to human metapneumovirus (HMPV) by the age of 5 y. This study aimed to describe the morbidity associated with HMPV infections in a cohort of children in the Midwest of the United States.METHODS:This was a retrospective 2-center cohort study including children (0–17 y old) hospitalized with HMPV infections at 2 tertiary care pediatric hospitals from 2009 to 2013. Demographics, chronic medical conditions, viral coinfections, and hospitalization characteristics, including the need for respiratory support, high-flow nasal cannula, CPAP, bi-level positive airway pressure, invasive mechanical ventilation, pediatric ICU admission, acute kidney injury (AKI), use of extracorporeal membrane oxygenation, and length of stay, were collected.RESULTS:In total, 131 subjects were included. Those with one or more comorbidities were older than their otherwise healthy counterparts, with a median age of 2.8 y (interquartile range [IQR] 1.1–7.0) compared to 1.3 y (IQR 0.6–2.0, P < .001), respectively. Ninety-nine (75.6%) subjects required respiratory support; 72 (55.0%) subjects required nasal cannula, simple face mask, or tracheostomy mask as their maximum support. Additionally, 1 (0.8%) subject required high-flow nasal cannula, 1 (0.8%) subject required CPAP, 2 (1.5%) subjects required bi-level positive airway pressure, 15 (11.5%) subjects required invasive mechanical ventilation, 4 (3.1%) subjects required high-frequency oscillatory or jet ventilation, and 4 (3.1%) subjects required extracorporeal membrane oxygenation. Fifty-one (38.9%) subjects required pediatric ICU admission, and 16 (12.2%) subjects developed AKI. Subjects with AKI were significantly older than those without AKI at 5.4 y old (IQR 1.6–11.7) versus 1.9 y old (IQR 0.7–3.5, P = .003). After controlling for the presence of at least one comorbidity and cystic fibrosis, each year increase in age led to a 16% increase in the odds of AKI (P = .01). The median length of stay for the entire cohort was 4.0 d (IQR 2.7–7.0).CONCLUSIONS:Children hospitalized with HMPV may be at risk for AKI. Risk of HMPV-associated AKI appears to increase with age regardless of severity of respiratory illness or presence of comorbidities.




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Correction to "Quantitative Proteomics of Clinically Relevant Drug-Metabolizing Enzymes and Drug Transporters and Their Intercorrelations in the Human Small Intestine" [Errata]




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Circadian Clock-Controlled Drug Metabolism: Implications for Chronotherapeutics [Minireview]

Dependence of drug metabolism on dosing time has long been recognized. However, only recently are the underlying mechanisms for circadian drug metabolism being clarified. Diurnal rhythmicity in expression of drug-metabolizing enzymes is believed to be a key factor determining circadian metabolism. Supporting the notion that biological rhythms are generated and maintained by the circadian clock, a number of diurnal enzymes are under the control of the circadian clock. In general, circadian clock genes generate and regulate diurnal rhythmicity in drug-metabolizing enzymes via transcriptional actions on one or two of three cis-elements (i.e., E-box, D-box, and Rev-erb response element or RAR-related orphan receptor response element). Additionally, cycling or clock-controlled nuclear receptors such as hepatocyte nuclear factor 4α and peroxisome proliferator–activated receptor are contributors to diurnal enzyme expression. These newly discovered mechanisms for each of the rhythmic enzymes are reviewed in this article. We also discuss how the rhythms of enzymes are translated to circadian pharmacokinetics and drug chronotoxicity, which has direct implications for chronotherapeutics. Our discussion is also extended to two diurnal transporters (P-glycoprotein and multidrug resistance-associated protein 2) that have an important role in drug absorption. Although the experimental evidence is lacking in metabolism-based chronoefficacy, circadian genes (e.g., Rev-erbα) as drug targets are shown to account for diurnal variability in drug efficacy.

SIGNIFICANCE STATEMENT

Significant progress has been made in understanding the molecular mechanisms for generation of diurnal rhythmicity in drug-metabolizing enzymes. In this article, we review the newly discovered mechanisms for each of the rhythmic enzymes and discuss how the rhythms of enzymes are translated to circadian pharmacokinetics and drug chronotoxicity, which has direct implications for chronotherapeutics.




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Ontogeny and Cross-species Comparison of Pathways Involved in Drug Absorption, Distribution, Metabolism, and Excretion in Neonates (Review): Kidney [Minireview]

The kidneys play an important role in many processes, including urine formation, water conservation, acid-base equilibrium, and elimination of waste. The anatomic and functional development of the kidney has different maturation time points in humans versus animals, with critical differences between species in maturation before and after birth. Absorption, distribution, metabolism, and excretion (ADME) of drugs vary depending on age and maturation, which will lead to differences in toxicity and efficacy. When neonate/juvenile laboratory animal studies are designed, a thorough knowledge of the differences in kidney development between newborns/children and laboratory animals is essential. The human and laboratory animal data must be combined to obtain a more complete picture of the development in the kidneys around the neonatal period and the complexity of ADME in newborns and children. This review examines the ontogeny and cross-species differences in ADME processes in the developing kidney in preterm and term laboratory animals and children. It provides an overview of insights into ADME functionality in the kidney by identifying what is currently known and which gaps still exist. Currently important renal function properties such as glomerular filtration rate, renal blood flow, and ability to concentrate are generally well known, while detailed knowledge about transporter and metabolism maturation is growing but is still lacking. Preclinical data in those properties is limited to rodents and generally covers only the expression levels of transporter or enzyme-encoding genes. More knowledge on a functional level is needed to predict the kinetics and toxicity in neonate/juvenile toxicity and efficacy studies.

SIGNIFICANCE STATEMENT

This review provides insight in cross-species developmental differences of absorption, distribution, metabolism, and excretion properties in the kidney, which should be considered in neonate/juvenile study interpretation, hypotheses generation, and experimental design.




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Theophylline Acetaldehyde as the Initial Product in Doxophylline Metabolism in Human Liver [Articles]

Doxophylline (DOXO) and theophylline are widely used as bronchodilators for treating asthma and chronic obstructive pulmonary disease, and DOXO has a better safety profile than theophylline. How DOXO’s metabolism and disposition affect its antiasthmatic efficacy and safety remains to be explored. In this study, the metabolites of DOXO were characterized. A total of nine metabolites of DOXO were identified in vitro using liver microsomes from human and four other animal species. Among them, six metabolites were reported for the first time. The top three metabolites were theophylline acetaldehyde (M1), theophylline-7-acetic acid (M2), and etophylline (M4). A comparative analysis of DOXO metabolism in human using liver microsomes, S9 fraction, and plasma samples demonstrated the following: 1) The metabolism of DOXO began with a cytochrome P450 (P450)–mediated, rate-limiting step at the C ring and produced M1, the most abundant metabolite in human liver microsomes. However, in human plasma, the M1 production was rather low. 2) M1 was further converted to M2 and M4, the end products of DOXO metabolism in vivo, by non-P450 dismutase in the cytosol. This dismutation process also relied on the ratio of NADP+/NADPH in the cell. These findings for the first time elucidated the metabolic sites and routes of DOXO metabolism in human.

SIGNIFICANCE STATEMENT

We systematically characterized doxophylline metabolism using in vitro and in vivo assays. Our findings evolved the understandings of metabolic sites and pathways for methylxanthine derivatives with the aldehyde functional group.




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Acetaminophen-Induced Liver Injury Alters Expression and Activities of Cytochrome P450 Enzymes in an Age-Dependent Manner in Mouse Liver [Articles]

Drug-induced liver injury (DILI) is a global medical problem. The risk of DILI is often related to expression and activities of drug-metabolizing enzymes, especially cytochrome P450s (P450s). However, changes on expression and activities of P450s after DILI have not been determined. The aim of this study is to fill this knowledge gap. Acetaminophen (APAP) was used as a model drug to induce DILI in C57BL/6J mice at different ages of days 10 (infant), 22 (child), and 60 (adult). DILI was assessed by levels of alanine aminotransferase and aspartate aminotransferase in plasma with a confirmation by H&E staining on liver tissue sections. The expression of selected P450s at mRNA and protein levels was measured by real-time polymerase chain reaction and liquid chromatography–tandem mass spectrometry, respectively. The activities of these P450s were determined by the formation of metabolites from probe drugs for each P450 using ultraperformance liquid chromatography–quadrupole time of flight mass spectrometry. DILI was induced at mild to severe levels in a dose-dependent manner in 200, 300, and 400 mg/kg APAP-treated groups at child and adult ages, but not at the infant age. Significantly decreased expression at mRNA and protein levels as well as enzymatic activities of CYP2E1, 3A11, 1A2, and 2C29 were found at child and adult ages. Adult male mice were more susceptible to APAP-induced liver injury than female mice with more decreased expression of P450s. These results suggest that altered levels of P450s in livers severely injured by drugs may affect the therapeutic efficacy of drugs, which are metabolized by P450s, more particularly for males.

SIGNIFICANCE STATEMENT

The current study in an animal model demonstrates that acetaminophen-induced liver injury results in decreased expression and enzyme activities of several examined drug-metabolizing cytochrome P450s (P450s). The extent of such decreases is correlated to the degree of liver injury severity. The generated data may be translated to human health for patients who have drug-induced liver injury with decreased capability to metabolize drugs by certain P450s.




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Drug Metabolism and Disposition




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Perturbation of phosphoglycerate kinase 1 (PGK1) only marginally affects glycolysis in cancer cells [Metabolism]

Phosphoglycerate kinase 1 (PGK1) plays important roles in glycolysis, yet its forward reaction kinetics are unknown, and its role especially in regulating cancer cell glycolysis is unclear. Here, we developed an enzyme assay to measure the kinetic parameters of the PGK1-catalyzed forward reaction. The Km values for 1,3-bisphosphoglyceric acid (1,3-BPG, the forward reaction substrate) were 4.36 μm (yeast PGK1) and 6.86 μm (human PKG1). The Km values for 3-phosphoglycerate (3-PG, the reverse reaction substrate and a serine precursor) were 146 μm (yeast PGK1) and 186 μm (human PGK1). The Vmax of the forward reaction was about 3.5- and 5.8-fold higher than that of the reverse reaction for the human and yeast enzymes, respectively. Consistently, the intracellular steady-state concentrations of 3-PG were between 180 and 550 μm in cancer cells, providing a basis for glycolysis to shuttle 3-PG to the serine synthesis pathway. Using siRNA-mediated PGK1-specific knockdown in five cancer cell lines derived from different tissues, along with titration of PGK1 in a cell-free glycolysis system, we found that the perturbation of PGK1 had no effect or only marginal effects on the glucose consumption and lactate generation. The PGK1 knockdown increased the concentrations of fructose 1,6-bisphosphate, dihydroxyacetone phosphate, glyceraldehyde 3-phosphate, and 1,3-BPG in nearly equal proportions, controlled by the kinetic and thermodynamic states of glycolysis. We conclude that perturbation of PGK1 in cancer cells insignificantly affects the conversion of glucose to lactate in glycolysis.




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Abnormal Fetal Echocardiogram at 33 Weeks Gestation




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Genomic Investigation Reveals Contaminated Detergent as the Source of an Extended-Spectrum-{beta}-Lactamase-Producing Klebsiella michiganensis Outbreak in a Neonatal Unit [Bacteriology]

Klebsiella species are problematic pathogens in neonatal units and may cause outbreaks, for which the sources of transmission may be challenging to elucidate. We describe the use of whole-genome sequencing (WGS) to investigate environmental sources of transmission during an outbreak of extended-spectrum-β-lactamase (ESBL)-producing Klebsiella michiganensis colonizing neonates. Ceftriaxone-resistant Klebsiella spp. isolated from neonates (or their mothers) and the hospital environment were included. Short-read sequencing (Illumina) and long-read sequencing (MinION; Oxford Nanopore Technologies) were used to confirm species taxonomy, to identify antimicrobial resistance genes, and to determine phylogenetic relationships using single-nucleotide polymorphism profiling. A total of 21 organisms (10 patient-derived isolates and 11 environmental isolates) were sequenced. Standard laboratory methods identified the outbreak strain as an ESBL-producing Klebsiella oxytoca, but taxonomic assignment from WGS data suggested closer identity to Klebsiella michiganensis. Strains isolated from multiple detergent-dispensing bottles were either identical or closely related by single-nucleotide polymorphism comparison. Detergent bottles contaminated by K. michiganensis had been used for washing milk expression equipment. No new cases were identified once the detergent bottles were removed. Environmental reservoirs may be an important source in outbreaks of multidrug-resistant organisms. WGS, in conjunction with traditional epidemiological investigation, can be instrumental in revealing routes of transmission and guiding infection control responses.




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Fourier Transform Infrared Spectroscopy Is a New Option for Outbreak Investigation: a Retrospective Analysis of an Extended-Spectrum-Beta-Lactamase-Producing Klebsiella pneumoniae Outbreak in a Neonatal Intensive Care Unit [Epidemiology]

The IR Biotyper is a new automated typing system based on Fourier-transform infrared (FT-IR) spectroscopy that gives results within 4 h. We aimed (i) to use the IR Biotyper to retrospectively analyze an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) in a neonatal intensive care unit and to compare results to BOX-PCR and whole-genome sequencing (WGS) results as the gold standard and (ii) to assess how the cutoff values used to define clusters affect the discriminatory power of the IR Biotyper. The sample consisted of 18 isolates from 14 patients. Specimens were analyzed in the IR Biotyper using the default analysis settings, and spectra were analyzed using OPUS 7.5 software. The software contains a feature that automatically proposes a cutoff value to define clusters; the cutoff value defines up to which distance the spectra are considered to be in the same cluster. Based on FT-IR, the outbreak represented 1 dominant clone, 1 secondary clone, and several unrelated clones. FT-IR results, using the cutoff value generated by the accompanying software after 4 replicates, were concordant with WGS for all but 1 isolate. BOX-PCR was underdiscriminatory compared to the other two methods. Using the cutoff value generated after 12 replicates, the results of FT-IR and WGS were completely concordant. The IR Biotyper can achieve the same typeability and discriminatory power as genome-based methods. However, to attain this high performance requires either previous, strain-dependent knowledge about the optimal technical parameters to be used or validation by a second method.




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Transcriptome reconstruction and functional analysis of eukaryotic marine plankton communities via high-throughput metagenomics and metatranscriptomics [METHOD]

Large-scale metagenomic and metatranscriptomic data analyses are often restricted by their gene-centric approach, limiting the ability to understand organismal and community biology. De novo assembly of large and mosaic eukaryotic genomes from complex meta-omics data remains a challenging task, especially in comparison with more straightforward bacterial and archaeal systems. Here, we use a transcriptome reconstruction method based on clustering co-abundant genes across a series of metagenomic samples. We investigated the co-abundance patterns of ~37 million eukaryotic unigenes across 365 metagenomic samples collected during the Tara Oceans expeditions to assess the diversity and functional profiles of marine plankton. We identified ~12,000 co-abundant gene groups (CAGs), encompassing ~7 million unigenes, including 924 metagenomics-based transcriptomes (MGTs, CAGs larger than 500 unigenes). We demonstrated the biological validity of the MGT collection by comparing individual MGTs with available references. We identified several key eukaryotic organisms involved in dimethylsulfoniopropionate (DMSP) biosynthesis and catabolism in different oceanic provinces, thus demonstrating the potential of the MGT collection to provide functional insights on eukaryotic plankton. We established the ability of the MGT approach to capture interspecies associations through the analysis of a nitrogen-fixing haptophyte-cyanobacterial symbiotic association. This MGT collection provides a valuable resource for analyses of eukaryotic plankton in the open ocean by giving access to the genomic content and functional potential of many ecologically relevant eukaryotic species.




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Endogenous PAD4 in Breast Cancer Cells Mediates Cancer Extracellular Chromatin Network Formation and Promotes Lung Metastasis

Peptidyl arginine deiminase 4 (PAD4/PADI4) is a posttranslational modification enzyme that converts protein arginine or mono-methylarginine to citrulline. The PAD4-mediated hypercitrullination reaction in neutrophils causes the release of nuclear chromatin to form a chromatin network termed neutrophil extracellular traps (NET). NETs were first described as antimicrobial fibers that bind and kill bacteria. However, it is not known whether PAD4 can mediate the release of chromatin DNA into the extracellular space of cancer cells. Here, we report that murine breast cancer 4T1 cells expressing high levels of PADI4 can release cancer extracellular chromatin networks (CECN) in vitro and in vivo. Deletion of Padi4 using CRISPR/Cas9 abolished CECN formation in 4T1 cells. Padi4 deletion from 4T1 cells also reduced the rate of tumor growth in an allograft model, and decreased lung metastasis by 4T1 breast cancers. DNase I treatment, which degrades extracellular DNA including CECNs, also reduced breast to lung metastasis of Padi4 wild-type 4T1 cells in allograft experiments in the Padi4-knockout mice. We further demonstrated that DNase I treatment in this mouse model did not alter circulating tumor cells but decreased metastasis through steps after intravasation. Taken together, our genetic studies show that PAD4 plays a cell autonomous role in cancer metastasis, thus revealing a novel strategy for preventing cancer metastasis by inhibiting cancer cell endogenous PAD4.

Implications:

This study shows that PADI4 can mediate the formation of CECNs in 4T1 cells, and that endogenous PADI4 plays an essential role in breast cancer lung metastasis.

Visual Overview:

http://mcr.aacrjournals.org/content/molcanres/18/5/735/F1.large.jpg.




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OLR1 Promotes Pancreatic Cancer Metastasis via Increased c-Myc Expression and Transcription of HMGA2

Pancreatic cancer is one of the most lethal human malignancies, partly because of its propensity for metastasis. However, the mechanisms of metastasis in pancreatic cancer remain unclear. Oxidized low-density lipoprotein receptor 1 (OLR1), a lectin-like scavenger receptor that recognizes several ligands, such as oxidized low-density lipoprotein, was previously reported in cardiovascular and metabolic diseases. The role and mechanism of OLR1 in pancreatic cancer is unclear. In this study, we found that OLR1 expression was significantly higher in pancreatic cancer tissues than that in adjacent normal tissues and closely associated with reduced overall survival. OLR1 promoted proliferation and metastasis of pancreatic cancer cells in vitro and in vivo. Mechanistically, OLR1 increased HMGA2 transcription by upregulating c-Myc expression to promote the metastasis of pancreatic cancer cells. In addition, patients with pancreatic cancer with high expression of OLR1–c-Myc–HMGA2 axis showed worse prognosis compared with patients with low expression of OLR1–c-Myc–HMGA2 axis.

Implications:

Our findings suggested that the OLR1–c-Myc–HMGA2 axis promotes metastasis of pancreatic cancer cells and may serve as potential therapeutic targets and prognosis markers for patients with pancreatic cancer.




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Pre-eclamptic Fetal Programming Alters Neuroinflammatory and Cardiovascular Consequences of Endotoxemia in Sex-Specific Manners [Neuropharmacology]

Pre-eclampsia (PE)-induced fetal programming predisposes offspring to health hazards in adult life. Here, we tested the hypothesis that pre-eclamptic fetal programming elicits sexually dimorphic inflammatory and cardiovascular complications to endotoxemia in adult rat offspring. PE was induced by oral administration of L-NAME (50 mg/kg per day for seven consecutive days) starting from day 14 of conception. Cardiovascular studies were performed in conscious adult male and female offspring preinstrumented with femoral indwelling catheters. Compared with non-PE male counterparts, intravenous administration of lipopolysaccharide (LPS, 5 mg/kg) to PE male offspring caused significantly greater 1) falls in blood pressure, 2) increases in heart rate, 3) rises in arterial dP/dtmax, a correlate of left ventricular contractility, and 4) decreases in time- and frequency-domain indices of heart rate variability (HRV). By contrast, the hypotensive and tachycardic actions of LPS in female offspring were independent of the pre-eclamptic state and no clear changes in HRV or dP/dtmax were noted. Measurement of arterial baroreflex activity by vasoactive method revealed no sex specificity in baroreflex dysfunction induced by LPS. Immunohistochemical studies showed increased protein expression of toll-like receptor 4 in heart as well as in brainstem neuronal pools of the nucleus of solitary tract and rostral ventrolateral medulla in endotoxic PE male, but not female, offspring. Enhanced myocardial, but not neuronal, expression of monocyte chemoattractant protein-1 was also demonstrated in LPS-treated male offspring. Together, pre-eclamptic fetal programming aggravates endotoxic manifestations of hypotension and autonomic dysfunction in male offspring via exacerbating myocardial and neuromedullary inflammatory pathways.

SIGNIFICANCE STATEMENT

Current molecular and neuroanatomical evidence highlights a key role for pre-eclamptic fetal programming in offspring predisposition to health hazards induced by endotoxemia in adult life. Pre-eclampsia accentuates endotoxic manifestations of hypotension, tachycardia, and cardiac autonomic dysfunction in male offspring via exacerbating myocardial and central inflammatory pathways. The absence of such detrimental effects in female littermates suggests sexual dimorphism in the interaction of pre-eclamptic fetal programming with endotoxemia.




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Hepatic Transporter Alterations by Nuclear Receptor Agonist T0901317 in Sandwich-Cultured Human Hepatocytes: Proteomic Analysis and PBPK Modeling to Evaluate Drug-Drug Interaction Risk [Metabolism, Transport, and Pharmacogenomics]

In vitro approaches for predicting drug-drug interactions (DDIs) caused by alterations in transporter protein regulation are not well established. However, reports of transporter regulation via nuclear receptor (NR) modulation by drugs are increasing. This study examined alterations in transporter protein levels in sandwich-cultured human hepatocytes (SCHH; n = 3 donors) measured by liquid chromatography–tandem mass spectrometry–based proteomic analysis after treatment with N-[4-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)phenyl]-N-(2,2,2-trifluoroethyl)benzenesulfonamide (T0901317), the first described synthetic liver X receptor agonist. T0901317 treatment (10 μM, 48 hours) decreased the levels of organic cation transporter (OCT) 1 (0.22-, 0.43-, and 0.71-fold of control) and organic anion transporter (OAT) 2 (0.38-, 0.38-, and 0.53-fold of control) and increased multidrug resistance protein (MDR) 1 (1.37-, 1.48-, and 1.59-fold of control). The induction of NR downstream gene expression supports the hypothesis that T0901317 off-target effects on farnesoid X receptor and pregnane X receptor activation are responsible for the unexpected changes in OCT1, OAT2, and MDR1. Uptake of the OCT1 substrate metformin in SCHH was decreased by T0901317 treatment. Effects of decreased OCT1 levels on metformin were simulated using a physiologically-based pharmacokinetic (PBPK) model. Simulations showed a clear decrease in metformin hepatic exposure resulting in a decreased pharmacodynamic effect. This DDI would not be predicted by the modest changes in simulated metformin plasma concentrations. Altogether, the current study demonstrated that an approach combining SCHH, proteomic analysis, and PBPK modeling is useful for revealing tissue concentration–based DDIs caused by unexpected regulation of hepatic transporters by NR modulators.

SIGNIFICANCE STATEMENT

This study utilized an approach combining sandwich-cultured human hepatocytes, proteomic analysis, and physiologically based pharmacokinetic modeling to evaluate alterations in pharmacokinetics (PK) and pharmacodynamics (PD) caused by transporter regulation by nuclear receptor modulators. The importance of this approach from a mechanistic and clinically relevant perspective is that it can reveal drug-drug interactions (DDIs) caused by unexpected regulation of hepatic transporters and enable prediction of altered PK and PD changes, especially for tissue concentration–based DDIs.




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Regenerative responses following DNA damage - {beta}-catenin mediates head regrowth in the planarian Schmidtea mediterranea [RESEARCH ARTICLE]

Annelies Wouters, Jan-Pieter Ploem, Sabine A. S. Langie, Tom Artois, Aziz Aboobaker, and Karen Smeets

Pluripotent stem cells hold great potential for regenerative medicine. Increased replication and division, such is the case during regeneration, concomitantly increases the risk of adverse outcomes through the acquisition of mutations. Seeking for driving mechanisms of such outcomes, we challenged a pluripotent stem cell system during the tightly controlled regeneration process in the planarian Schmidtea mediterranea. Exposure to the genotoxic compound methyl methanesulfonate (MMS) revealed that despite a similar DNA-damaging effect along the anteroposterior axis of intact animals, responses differed between anterior and posterior fragments after amputation. Stem cell proliferation and differentiation proceeded successfully in the amputated heads, leading to regeneration of missing tissues. Stem cells in the amputated tails showed decreased proliferation and differentiation capacity. As a result, tails could not regenerate. Interference with the body-axis-associated component β-catenin-1 increased regenerative success in tail fragments by stimulating proliferation at an early time point. Our results suggest that differences in the Wnt signalling gradient along the body axis modulate stem cell responses to MMS.




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Proteinase-Activated Receptor 4 Activation Triggers Cell Membrane Blebbing through RhoA and {beta}-Arrestin [Articles]

Proteinase-activated receptors (PARs) are a four-member family of G-protein–coupled receptors that are activated via proteolysis. PAR4 is a member of this family that is cleaved and activated by serine proteinases such as thrombin, trypsin, and cathepsin-G. PAR4 is expressed in a variety of tissues and cell types, including platelets, vascular smooth muscle cells, and neuronal cells. In studying PAR4 signaling and trafficking, we observed dynamic changes in the cell membrane, with spherical membrane protrusions that resemble plasma membrane blebbing. Since nonapoptotic membrane blebbing is now recognized as an important regulator of cell migration, cancer cell invasion, and vesicular content release, we sought to elucidate the signaling pathway downstream of PAR4 activation that leads to such events. Using a combination of pharmacological inhibition and CRISPR/CRISPR-associated protein 9 (Cas9)–mediated gene editing approaches, we establish that PAR4-dependent membrane blebbing occurs independently of the Gαq/11- and Gαi-signaling pathways and is dependent on signaling via the β-arrestin-1/2 and Ras homolog family member A (RhoA) signaling pathways. Together these studies provide further mechanistic insight into PAR4 regulation of cellular function.

SIGNIFICANCE STATEMENT

We find that the thrombin receptor PAR4 triggers cell membrane blebbing in a RhoA–and β-arrestin–dependent manner. In addition to identifying novel cellular responses mediated by PAR4, these data provide further evidence for biased signaling in PAR4 since membrane blebbing was dependent on some, but not all, signaling pathways activated by PAR4.




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Additional Local Therapy for Liver Metastases in Patients with Metastatic Castration-Resistant Prostate Cancer Receiving Systemic PSMA-Targeted Therapy

The aim of this study was to evaluate the efficacy of 177Lu-prostate-specific membrane antigen (PSMA)-617 (177Lu-PSMA) and selective internal radiation therapy (SIRT) for the treatment of liver metastases of castration-resistant prostate cancer. Methods: Safety and survival of patients with metastatic castration-resistant prostate cancer and liver metastases assigned to 177Lu-PSMA alone (n = 31) or in combination with SIRT (n = 5) were retrospectively analyzed. Additionally, a subgroup (n = 10) was analyzed using morphologic and molecular response criteria. Results: Median estimated survival was 5.7 mo for 177Lu-PSMA alone and 8.4 mo for combined sequential 177Lu-PSMA and SIRT. 177Lu-PSMA achieved discordant therapy responses with both regressive and progressive liver metastases in the same patient (best vs. worst responding metastases per patient: –35% vs. +63% diameter change; P < 0.05). SIRT was superior to 177Lu-PSMA for the treatment of liver metastases (0% vs. 56% progression). Conclusion: The combination of 177Lu-PSMA and SIRT is efficient and feasible for the treatment of advanced prostate cancer. 177Lu-PSMA alone seems to have limited response rates in the treatment of liver metastases.




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Assessing Radiographic Response to 223Ra with an Automated Bone Scan Index in Metastatic Castration-Resistant Prostate Cancer Patients

For effective clinical management of patients being treated with 223Ra, there is a need for radiographic response biomarkers to minimize disease progression and to stratify patients for subsequent treatment options. The objective of this study was to evaluate an automated bone scan index (aBSI) as a quantitative assessment of bone scans for radiographic response in patients with metastatic castration-resistant prostate cancer (mCRPC). Methods: In a multicenter retrospective study, bone scans from patients with mCRPC treated with monthly injections of 223Ra were collected from 7 hospitals in Sweden. Patients with available bone scans before treatment with 223Ra and at treatment discontinuation were eligible for the study. The aBSI was generated at baseline and at treatment discontinuation. The Spearman rank correlation was used to correlate aBSI with the baseline covariates: alkaline phosphatase (ALP) and prostate-specific antigen (PSA). The Cox proportional-hazards model and Kaplan–Meier curve were used to evaluate the association of covariates at baseline and their change at treatment discontinuation with overall survival (OS). The concordance index (C-index) was used to evaluate the discriminating strength of covariates in predicting OS. Results: Bone scan images at baseline were available from 156 patients, and 67 patients had both a baseline and a treatment discontinuation bone scan (median, 5 doses; interquartile range, 3–6 doses). Baseline aBSI (median, 4.5; interquartile range, 2.4–6.5) was moderately correlated with ALP (r = 0.60, P < 0.0001) and with PSA (r = 0.38, P = 0.003). Among baseline covariates, aBSI (P = 0.01) and ALP (P = 0.001) were significantly associated with OS, whereas PSA values were not (P = 0.059). After treatment discontinuation, 36% (24/67), 80% (54/67), and 13% (9/67) of patients demonstrated a decline in aBSI, ALP, and PSA, respectively. As a continuous variable, the relative change in aBSI after treatment, compared with baseline, was significantly associated with OS (P < 0.0001), with a C-index of 0.67. Median OS in patients with both aBSI and ALP decline (median, 134 wk) was significantly longer than in patients with ALP decline only (median, 77 wk; P = 0.029). Conclusion: Both aBSI at baseline and its change at treatment discontinuation were significant parameters associated with OS. The study warrants prospective validation of aBSI as a quantitative imaging response biomarker to predict OS in patients with mCRPC treated with 223Ra.




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Low adherence to inhaled corticosteroids/long-acting {beta}2-agonists and biologic treatment in severe asthmatics

Eligibility criteria for a biologic treatment for severe asthma include poor disease control despite a full medication plan according to Global Initiative for Asthma steps 4–5 [1]. Adherence to inhaled therapy should be verified as part of that prescription requirement [2]. In fact, it has been demonstrated that poor adherence is a major cause of uncontrolled asthma, regardless of its severity [3]. Furthermore, biologics do not exert a disease-modifying effect [4]; in contrast to allergen immunotherapy, which is able to permanently modulate the way the immune system reacts to allergens beyond the immunotherapy treatment course [5], biologic therapy withdrawal usually leads to asthma relapse [4]. Thus, a low adherence rate to inhaled treatment in patients undergoing biologic therapy raises some issues related to sustainability.




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Tetanus Toxin cis-Loop Contributes to Light-Chain Translocation

ABSTRACT

The clostridial neurotoxins (CNTs) comprise tetanus toxin (TT) and botulinum neurotoxin (BoNT [BT]) serotypes (A to G and X) and several recently identified CNT-like proteins, including BT/En and the mosquito BoNT-like toxin Pmp1. CNTs are produced as single proteins cleaved to a light chain (LC) and a heavy chain (HC) connected by an interchain disulfide bond. LC is a zinc metalloprotease (cleaving soluble N-ethylmaleimide-sensitive factor attachment protein receptors [SNAREs]), while HC contains an N-terminal translocation domain (HCN) and a C-terminal receptor binding domain (HCC). HCN-mediated LC translocation is the least understood function of CNT action. Here, β-lactamase (βlac) was used as a reporter in discovery-based live-cell assays to characterize TT-mediated LC translocation. Directed mutagenesis identified a role for a charged loop (767DKE769) connecting α15 and α16 (cis-loop) within HCN in LC translocation; aliphatic substitution inhibited LC translocation but not other toxin functions such as cell binding, intracellular trafficking, or HCN-mediated pore formation. K768 was conserved among the CNTs. In molecular simulations of the HCN with a membrane, the cis-loop did not bind with the cell membrane. Taken together, the results of these studies implicate the cis-loop in LC translocation, independently of pore formation.

IMPORTANCE How protein toxins translocate their catalytic domain across a cell membrane is the least understood step in toxin action. This study utilized a reporter, β-lactamase, that was genetically fused to full-length, nontoxic tetanus toxin (βlac-TT) in discovery-based live-cell assays to study LC translocation. Directed mutagenesis identified a role for K768 in LC translocation. K768 was located between α15 and α16 (termed the cis-loop). Cellular assays showed that K768 did not interfere with other toxin functions, including cell binding, intracellular trafficking, and pore formation. The equivalent K768 is conserved among the clostridial neurotoxin family of proteins as a conserved structural motif. The cis-loop appears to contribute to LC translocation.




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Lack of Evidence for Microbiota in the Placental and Fetal Tissues of Rhesus Macaques

ABSTRACT

The prevailing paradigm in obstetrics has been the sterile womb hypothesis. However, some are asserting that the placenta, intra-amniotic environment, and fetus harbor microbial communities. The objective of this study was to determine whether the fetal and placental tissues of rhesus macaques harbor bacterial communities. Fetal, placental, and uterine wall samples were obtained from cesarean deliveries without labor (~130/166 days gestation). The presence of bacteria in the fetal intestine and placenta was investigated through culture. The bacterial burden and profiles of the placenta, umbilical cord, and fetal brain, heart, liver, and colon were determined through quantitative real-time PCR and DNA sequencing. These data were compared with those of the uterine wall as well as to negative and positive technical controls. Bacterial cultures of fetal and placental tissues yielded only a single colony of Cutibacterium acnes. This bacterium was detected at a low relative abundance (0.02%) in the 16S rRNA gene profile of the villous tree sample from which it was cultured, yet it was also identified in 12/29 background technical controls. The bacterial burden and profiles of fetal and placental tissues did not exceed or differ from those of background technical controls. By contrast, the bacterial burden and profiles of positive controls exceeded and differed from those of background controls. Among the macaque samples, distinct microbial signals were limited to the uterine wall. Therefore, using multiple modes of microbiologic inquiry, there was not consistent evidence of bacterial communities in the fetal and placental tissues of rhesus macaques.

IMPORTANCE Microbial invasion of the amniotic cavity (i.e., intra-amniotic infection) has been causally linked to pregnancy complications, especially preterm birth. Therefore, if the placenta and the fetus are typically populated by low-biomass microbial communities, current understanding of the role of microbes in reproduction and pregnancy outcomes will need to be fundamentally reconsidered. Could these communities be of benefit by competitively excluding potential pathogens or priming the fetal immune system for the microbial bombardment it will experience upon delivery? If so, what properties (e.g., microbial load and community membership) of these microbial communities preclude versus promote intra-amniotic infection? Given the ramifications of the in utero colonization hypothesis, critical evaluation is required. In this study, using multiple modes of microbiologic inquiry (i.e., culture, quantitative real-time PCR [qPCR], and DNA sequencing) and controlling for potential background DNA contamination, we did not find consistent evidence for microbial communities in the placental and fetal tissues of rhesus macaques.




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Detecting and Monitoring Porcine Hemagglutinating Encephalomyelitis Virus, an Underresearched Betacoronavirus

ABSTRACT

Members of family Coronaviridae cause a variety of diseases in birds and mammals. Porcine hemagglutinating encephalomyelitis virus (PHEV), a lesser-researched coronavirus, can infect naive pigs of any age, but clinical disease is observed in pigs ≤4 weeks of age. No commercial PHEV vaccines are available, and neonatal protection from PHEV-associated disease is presumably dependent on lactogenic immunity. Although subclinical PHEV infections are thought to be common, PHEV ecology in commercial swine herds is unknown. To begin to address this gap in knowledge, a serum IgG antibody enzyme-linked immunosorbent assay (ELISA) based on the S1 protein was developed and evaluated on known-status samples and then used to estimate PHEV seroprevalence in U.S. sow herds. Assessment of the diagnostic performance of the PHEV S1 ELISA using serum samples (n = 924) collected from 7-week-old pigs (n = 84; 12 pigs per group) inoculated with PHEV, porcine epidemic diarrhea virus, transmissible gastroenteritis virus, porcine respiratory coronavirus, or porcine deltacoronavirus showed that a sample-to-positive cutoff value of ≥0.6 was both sensitive and specific, i.e., all PHEV-inoculated pigs were seropositive from days postinoculation 10 to 42, and no cross-reactivity was observed in samples from other groups. The PHEV S1 ELISA was then used to estimate PHEV seroprevalence in U.S. sow herds (19 states) using 2,756 serum samples from breeding females (>28 weeks old) on commercial farms (n = 104) with no history of PHEV-associated disease. The overall seroprevalence was 53.35% (confidence interval [CI], ±1.86%) and herd seroprevalence was 96.15% (CI, ±3.70%).

IMPORTANCE There is a paucity of information concerning the ecology of porcine hemagglutinating encephalomyelitis virus (PHEV) in commercial swine herds. This study provided evidence that PHEV infection is endemic and highly prevalent in U.S. swine herds. These results raised questions for future studies regarding the impact of endemic PHEV on swine health and the mechanisms by which this virus circulates in endemically infected populations. Regardless, the availability of the validated PHEV S1 enzyme-linked immunosorbent assay (ELISA) provides the means for swine producers to detect and monitor PHEV infections, confirm prior exposure to the virus, and to evaluate the immune status of breeding herds.




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Subtle Variations in Dietary-Fiber Fine Structure Differentially Influence the Composition and Metabolic Function of Gut Microbiota

ABSTRACT

The chemical structures of soluble fiber carbohydrates vary from source to source due to numerous possible linkage configurations among monomers. However, it has not been elucidated whether subtle structural variations might impact soluble fiber fermentation by colonic microbiota. In this study, we tested the hypothesis that subtle structural variations in a soluble polysaccharide govern the community structure and metabolic output of fermenting microbiota. We performed in vitro fecal fermentation studies using arabinoxylans (AXs) from different classes of wheat (hard red spring [AXHRS], hard red winter [AXHRW], and spring red winter [AXSRW]) with identical initial microbiota. Carbohydrate analyses revealed that AXSRW was characterized by a significantly shorter backbone and increased branching compared with those of the hard varieties. Amplicon sequencing demonstrated that fermentation of AXSRW resulted in a distinct community structure of significantly higher richness and evenness than those of hard-AX-fermenting cultures. AXSRW favored OTUs within Bacteroides, whereas AXHRW and AXHRS favored Prevotella. Accordingly, metabolic output varied between hard and soft varieties; higher propionate production was observed with AXSRW and higher butyrate and acetate with AXHRW and AXHRS. This study showed that subtle changes in the structure of a dietary fiber may strongly influence the composition and function of colonic microbiota, further suggesting that physiological functions of dietary fibers are highly structure dependent. Thus, studies focusing on interactions among dietary fiber, gut microbiota, and health outcomes should better characterize the structures of the carbohydrates employed.

IMPORTANCE Diet, especially with respect to consumption of dietary fibers, is well recognized as one of the most important factors shaping the colonic microbiota composition. Accordingly, many studies have been conducted to explore dietary fiber types that could predictably manipulate the colonic microbiota for improved health. However, the majority of these studies underappreciate the vastness of fiber structures in terms of their microbial utilization and omit detailed carbohydrate structural analysis. In some cases, this causes conflicting results to arise between studies using (theoretically) the same fibers. In this investigation, by performing in vitro fecal fermentation studies using bran arabinoxylans obtained from different classes of wheat, we showed that even subtle changes in the structure of a dietary fiber result in divergent microbial communities and metabolic outputs. This underscores the need for much higher structural resolution in studies investigating interactions of dietary fibers with gut microbiota, both in vitro and in vivo.




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An Extensive Meta-Metagenomic Search Identifies SARS-CoV-2-Homologous Sequences in Pangolin Lung Viromes

ABSTRACT

In numerous instances, tracking the biological significance of a nucleic acid sequence can be augmented through the identification of environmental niches in which the sequence of interest is present. Many metagenomic data sets are now available, with deep sequencing of samples from diverse biological niches. While any individual metagenomic data set can be readily queried using web-based tools, meta-searches through all such data sets are less accessible. In this brief communication, we demonstrate such a meta-metagenomic approach, examining close matches to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in all high-throughput sequencing data sets in the NCBI Sequence Read Archive accessible with the "virome" keyword. In addition to the homology to bat coronaviruses observed in descriptions of the SARS-CoV-2 sequence (F. Wu, S. Zhao, B. Yu, Y. M. Chen, et al., Nature 579:265–269, 2020, https://doi.org/10.1038/s41586-020-2008-3; P. Zhou, X. L. Yang, X. G. Wang, B. Hu, et al., Nature 579:270–273, 2020, https://doi.org/10.1038/s41586-020-2012-7), we note a strong homology to numerous sequence reads in metavirome data sets generated from the lungs of deceased pangolins reported by Liu et al. (P. Liu, W. Chen, and J. P. Chen, Viruses 11:979, 2019, https://doi.org/10.3390/v11110979). While analysis of these reads indicates the presence of a similar viral sequence in pangolin lung, the similarity is not sufficient to either confirm or rule out a role for pangolins as an intermediate host in the recent emergence of SARS-CoV-2. In addition to the implications for SARS-CoV-2 emergence, this study illustrates the utility and limitations of meta-metagenomic search tools in effective and rapid characterization of potentially significant nucleic acid sequences.

IMPORTANCE Meta-metagenomic searches allow for high-speed, low-cost identification of potentially significant biological niches for sequences of interest.




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The M Protein of Streptococcus pyogenes Strain AP53 Retains Cell Surface Functional Plasminogen Binding after Inactivation of the Sortase A Gene [Article]

Streptococcus pyogenes (Lancefield group A Streptococcus [GAS]) is a β-hemolytic human-selective pathogen that is responsible for a large number of morbid and mortal infections in humans. For efficient infection, GAS requires different types of surface proteins that provide various mechanisms for evading human innate immune responses, thus enhancing pathogenicity of the bacteria. Many such virulence-promoting proteins, including the major surface signature M protein, are translocated after biosynthesis through the cytoplasmic membrane and temporarily tethered to this membrane via a type 1 transmembrane domain (TMD) positioned near the COOH terminus. In these proteins, a sorting signal, LPXTG, is positioned immediately upstream of the TMD, which is cleaved by the membrane-associated transpeptidase, sortase A (SrtA), leading to the covalent anchoring of these proteins to newly emerging l-Ala–l-Ala cross-bridges of the growing peptidoglycan cell wall. Herein, we show that inactivation of the srtA gene in a skin-tropic pattern D GAS strain (AP53) results in retention of the M protein in the cell membrane. However, while the isogenic AP53 srtA strain is attenuated in overall pathogenic properties due to effects on the integrity of the cell membrane, our data show that the M protein nonetheless can extend from the cytoplasmic membrane through the cell wall and then to the surface of the bacteria and thereby retain its important properties of productively binding and activating fluid-phase host plasminogen (hPg). The studies presented herein demonstrate an underappreciated additional mechanism of cell surface display of bacterial virulence proteins via their retention in the cell membrane and extension to the GAS surface.

IMPORTANCE Group A Streptococcus pyogenes (GAS) is a human-specific pathogen that produces many surface factors, including its signature M protein, that contribute to its pathogenicity. M proteins undergo specific membrane localization and anchoring to the cell wall via the transpeptidase sortase A. Herein, we explored the role of sortase A function on M protein localization, architecture, and function, employing, a skin-tropic GAS isolate, AP53, which expresses a human plasminogen (hPg)-binding M (PAM) Protein. We showed that PAM anchored in the cell membrane, due to the targeted inactivation of sortase A, was nonetheless exposed on the cell surface and functionally interacted with host hPg. We demonstrate that M proteins, and possibly other sortase A-processed proteins that are retained in the cell membrane, can still function to initiate pathogenic processes by this underappreciated mechanism.




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On the Cretaceous origin of the Order Syracosphaerales and the genus Syracosphaera

New scanning electron microscope observations of unadulterated calcareous nannofossil assemblages on lamina surfaces of Cretaceous Tanzania Drilling Project sediments reveal high diversity in the <3 µm size-range and high abundances of small and frangible morphologies. These assemblages prompt comparison to modern assemblages, which show similar high diversity and abundance of very small and fragile taxa, although these assemblages are generally not preserved in the fossil record due to taphonomic filtering. Not only are there broad similarities between the general composition of modern assemblages and those of the Tanzanian lagerstätte, but also our discovery of several new Cretaceous taxa provides evidence for greatly extended fossil lineages of extant orders, with implications for both deep-time biodiversity divergence and survival through the end-Cretaceous mass extinction. Our findings include: new species that are the first-recorded Mesozoic representatives of the extant Syracosphaeraceae and Papposphaeraceae; potentially previously unrecorded diversity in the Mesozoic Calciosoleniaceae, another extant order, represented by extant species that have been described already; and new species and unusually high abundances of the Mesozoic Stephanolithiaceae. We also highlight the extended range of an incertae sedis Cenozoic genus, Ellipsolithus, into at least the Turonian.

Here, we describe seven new miniscule to very small Cretaceous species: Syracosphaera antiqua, S. repagula, Pocillithus macleodii, P. crucifer, Stradnerlithus wendleri, S.? haynesiae and Tortolithus foramen.




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Sex Disparities in Cardiovascular Outcome Trials of Populations With Diabetes: A Systematic Review and Meta-analysis

BACKGROUND

Sex differences have been described in diabetes cardiovascular outcome trials (CVOTs).

PURPOSE

We systematically reviewed for baseline sex differences in cardiovascular (CV) risk factors and CV protection therapy in diabetes CVOTs.

DATA SOURCES

Randomized placebo-controlled trials examining the effect of diabetes medications on major adverse cardiovascular events in people ≥18 years of age with type 2 diabetes.

STUDY SELECTION

Included trials reported baseline sex-specific CV risks and use of CV protection therapy.

DATA EXTRACTION

Two reviewers independently abstracted study data.

DATA SYNTHESIS

We included five CVOTs with 46,606 participants. We summarized sex-specific data using mean differences (MDs) and relative risks (RRs) and pooled estimates using random effects meta-analysis. There were fewer women than men in included trials (28.5–35.8% women). Women more often had stroke (RR 1.28; 95% CI 1.09, 1.50), heart failure (RR 1.30; 95% CI 1.21,1.40), and chronic kidney disease (RR 1.33; 95% CI 1.17; 1.51). They less often used statins (RR 0.90; 95% CI 0.86, 0.93), aspirin (RR 0.82; 95% CI 0.71, 0.95), and β-blockers (RR 0.93; 95% CI 0.88, 0.97) and had a higher systolic blood pressure (MD 1.66 mmHg; 95% CI 0.90, 2.41), LDL cholesterol (MD 0.34 mmol/L; 95% CI 0.29, 0.39), and hemoglobin A1c (MD 0.11%; 95% CI 0.09, 0.14 [1.2 mmol/mol; 1.0, 1.5]) than men.

LIMITATIONS

We could not carry out subgroup analyses due to the small number of studies. Our study is not generalizable to low CV risk groups nor to patients in routine care.

CONCLUSIONS

There were baseline sex disparities in diabetes CVOTs. We suggest efforts to recruit women into trials and promote CV management across the sexes.




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Effects of Continuous Glucose Monitoring on Metrics of Glycemic Control in Diabetes: A Systematic Review With Meta-analysis of Randomized Controlled Trials

BACKGROUND

Continuous glucose monitoring (CGM) provides important information to aid in achieving glycemic targets in people with diabetes.

PURPOSE

We performed a meta-analysis of randomized controlled trials (RCTs) comparing CGM with usual care for parameters of glycemic control in both type 1 and type 2 diabetes.

DATA SOURCES

Many electronic databases were searched for articles published from inception until 30 June 2019.

STUDY SELECTION

We selected RCTs that assessed both changes in HbA1c and time in target range (TIR), together with time below range (TBR), time above range (TAR), and glucose variability expressed as coefficient of variation (CV).

DATA EXTRACTION

Data were extracted from each trial by two investigators.

DATA SYNTHESIS

All results were analyzed by a random effects model to calculate the weighted mean difference (WMD) with the 95% CI. We identified 15 RCTs, lasting 12–36 weeks and involving 2,461 patients. Compared with the usual care (overall data), CGM was associated with modest reduction in HbA1c (WMD –0.17%, 95% CI –0.29 to –0.06, I2 = 96.2%), increase in TIR (WMD 70.74 min, 95% CI 46.73–94.76, I2 = 66.3%), and lower TAR, TBR, and CV, with heterogeneity between studies. The increase in TIR was significant and robust independently of diabetes type, method of insulin delivery, and reason for CGM use. In preplanned subgroup analyses, real-time CGM led to the higher improvement in mean HbA1c (WMD –0.23%, 95% CI –0.36 to –0.10, P < 0.001), TIR (WMD 83.49 min, 95% CI 52.68–114.30, P < 0.001), and TAR, whereas both intermittently scanned CGM and sensor-augmented pump were associated with the greater decline in TBR.

LIMITATIONS

Heterogeneity was high for most of the study outcomes; all studies were sponsored by industry, had short duration, and used an open-label design.

CONCLUSIONS

CGM improves glycemic control by expanding TIR and decreasing TBR, TAR, and glucose variability in both type 1 and type 2 diabetes.




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Accuracy of the Ottawa score in risk stratification of recurrent venous thromboembolism in patients with cancer-associated venous thromboembolism: a systematic review and meta-analysis

In patients with cancer-associated venous thromboembolism, knowledge of the estimated rate of recurrent events is important for clinical decision-making regarding anticoagulant therapy. The Ottawa score is a clinical prediction rule designed for this purpose, stratifying patients according to their risk of recurrent venous thromboembolism during the first six months of anticoagulation. We conducted a systematic review and meta-analysis of studies validating either the Ottawa score in its original or modified versions. Two investigators independently reviewed the relevant articles published from 1st June 2012 to 15th December 2018 and indexed in MEDLINE and EMBASE. Nine eligible studies were identified; these included a total of 14,963 patients. The original score classified 49.3% of the patients as high-risk, with a sensitivity of 0.7 [95% confidence interval (CI): 0.6-0.8], a 6-month pooled rate of recurrent venous thromboembolism of 18.6% (95%CI: 13.9-23.9). In the low-risk group, the recurrence rate was 7.4% (95%CI: 3.4-12.5). The modified score classified 19.8% of the patients as low-risk, with a sensitivity of 0.9 (95%CI: 0.4-1.0) and a 6-month pooled rate of recurrent venous thromboembolism of 2.2% (95%CI: 1.6-2.9). In the high-risk group, recurrence rate was 10.2% (95%CI: 6.4-14.6). Limitations of our analysis included type and dosing of anticoagulant therapy. We conclude that new therapeutic strategies are needed in patients at high risk for recurrent cancer-associated venous thromboembolism. Low-risk patients, as per the modified score, could be good candidates for oral anticoagulation. (This systematic review was registered with the International Prospective Registry of Systematic Reviews as: PROSPERO CRD42018099506).




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CRISPR/Cas9-mediated gene deletion efficiently retards the progression of Philadelphia-positive acute lymphoblastic leukemia in a p210 BCR-ABL1T315I mutation mouse model




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Erratum. WASH Regulates Glucose Homeostasis by Facilitating Glut2 Receptor Recycling in Pancreatic {beta}-Cells. Diabetes 2019;68:377-386




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A Phenotypic Screen Identifies Calcium Overload as a Key Mechanism of {beta}-Cell Glucolipotoxicity

Type 2 diabetes (T2D) is caused by loss of pancreatic β-cell mass and failure of the remaining β-cells to deliver sufficient insulin to meet demand. β-Cell glucolipotoxicity (GLT), which refers to combined, deleterious effects of elevated glucose and fatty acid levels on β-cell function and survival, contributes to T2D-associated β-cell failure. Drugs and mechanisms that protect β-cells from GLT stress could potentially improve metabolic control in patients with T2D. In a phenotypic screen seeking low-molecular-weight compounds that protected β-cells from GLT, we identified compound A that selectively blocked GLT-induced apoptosis in rat insulinoma cells. Compound A and its optimized analogs also improved viability and function in primary rat and human islets under GLT. We discovered that compound A analogs decreased GLT-induced cytosolic calcium influx in islet cells, and all measured β-cell–protective effects correlated with this activity. Further studies revealed that the active compound from this series largely reversed GLT-induced global transcriptional changes. Our results suggest that taming cytosolic calcium overload in pancreatic islets can improve β-cell survival and function under GLT stress and thus could be an effective strategy for T2D treatment.




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HRD1, an Important Player in Pancreatic {beta}-Cell Failure and Therapeutic Target for Type 2 Diabetic Mice

Inadequate insulin secretion in response to glucose is an important factor for β-cell failure in type 2 diabetes (T2D). Although HMG-CoA reductase degradation 1 (HRD1), a subunit of the endoplasmic reticulum–associated degradation complex, plays a pivotal role in β-cell function, HRD1 elevation in a diabetic setting contributes to β-cell dysfunction. We report in this study the excessive HRD1 expression in islets from humans with T2D and T2D mice. Functional studies reveal that β-cell–specific HRD1 overexpression triggers impaired insulin secretion that will ultimately lead to severe hyperglycemia; by contrast, HRD1 knockdown improves glucose control and response in diabetic models. Proteomic analysis results reveal a large HRD1 interactome, which includes v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA), a master regulator of genes implicated in the maintenance of β-cell function. Furthermore, mechanistic assay results indicate that HRD1 is a novel E3 ubiquitin ligase that targets MafA for ubiquitination and degradation in diabetic β-cells, resulting in cytoplasmic accumulation of MafA and in the reduction of its biological function in the nucleus. Our results not only reveal the pathological importance of excessive HRD1 in β-cell dysfunction but also establish the therapeutic importance of targeting HRD1 in order to prevent MafA loss and suppress the development of T2D.




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Vitamin D Receptor Overexpression in {beta}-Cells Ameliorates Diabetes in Mice

Vitamin D deficiency has been associated with increased incidence of diabetes, both in humans and in animal models. In addition, an association between vitamin D receptor (VDR) gene polymorphisms and diabetes has also been described. However, the involvement of VDR in the development of diabetes, specifically in pancreatic β-cells, has not been elucidated yet. Here, we aimed to study the role of VDR in β-cells in the pathophysiology of diabetes. Our results indicate that Vdr expression was modulated by glucose in healthy islets and decreased in islets from both type 1 diabetes and type 2 diabetes mouse models. In addition, transgenic mice overexpressing VDR in β-cells were protected against streptozotocin-induced diabetes and presented a preserved β-cell mass and a reduction in islet inflammation. Altogether, these results suggest that sustained VDR levels in β-cells may preserve β-cell mass and β-cell function and protect against diabetes.




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The Use of Mendelian Randomization to Determine the Role of Metabolic Traits on Urinary Albumin-to-Creatinine Ratio




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Pervasive Small RNAs in Cardiometabolic Research: Great Potential Accompanied by Biological and Technical Barriers

Advances in small RNA sequencing have revealed the enormous diversity of small noncoding RNA (sRNA) classes in mammalian cells. At this point, most investigators in diabetes are aware of the success of microRNA (miRNA) research and appreciate the importance of posttranscriptional gene regulation in glycemic control. Nevertheless, miRNAs are just one of multiple classes of sRNAs and likely represent only a minor fraction of sRNA sequences in a given cell. Despite the widespread appreciation of sRNAs, very little research into non-miRNA sRNA function has been completed, likely due to some major barriers that present unique challenges for study. To emphasize the importance of sRNA research in cardiometabolic diseases, we highlight the success of miRNAs and competitive endogenous RNAs in cholesterol and glucose metabolism. Moreover, we argue that sequencing studies have demonstrated that miRNAs are just the tip of the iceberg for sRNAs. We are likely standing at the precipice of immense discovery for novel sRNA-mediated gene regulation in cardiometabolic diseases. To realize this potential, we must first address critical barriers with an open mind and refrain from viewing non-miRNA sRNA function through the lens of miRNAs, as they likely have their own set of distinct regulatory factors and functional mechanisms.




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Starvation causes female-to-male sex reversal through lipid metabolism in the teleost fish, medaka (Olyzias latipes) [RESEARCH ARTICLE]

Yuta Sakae, Akira Oikawa, Yuki Sugiura, Masatoshi Mita, Shuhei Nakamura, Toshiya Nishimura, Makoto Suematsu, and Minoru Tanaka

The teleost fish, medaka (Oryzias latipes), employs the XX/XY genetic sex determination system. We show here that the phenotypic sex of medaka is affected by changes in lipid metabolism. Medaka larvae subjected to 5 days of starvation underwent female-to-male sex reversal. Metabolomic and RT-qPCR analyses indicated that pantothenate metabolism was suppressed by starvation. Consistently, inhibiting the pantothenate metabolic pathway caused sex reversal. The final metabolite in this pathway is coenzyme A, an essential factor for lipogenesis. Inhibiting fatty acid synthesis, the first step of lipogenesis, also caused sex reversal. The expression of dmrt1, a critical gene for male development, was suppressed by starvation, and a dmrt1 (13) mutant did not show sex reversal under starvation. Collectively, these results indicate that fatty acid synthesis is involved in female-to-male sex reversal through ectopic expression of male gene dmrt1 under starvation.




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Metabolic Disorders with Kidney Transplant

Metabolic disorders are highly prevalent in kidney transplant candidates and recipients and can adversely affect post-transplant graft outcomes. Management of diabetes, hyperparathyroidism, and obesity presents distinct opportunities to optimize patients both before and after transplant as well as the ability to track objective data over time to assess a patient’s ability to partner effectively with the health care team and adhere to complex treatment regimens. Optimization of these particular disorders can most dramatically decrease the risk of surgical and cardiovascular complications post-transplant. Approximately 60% of nondiabetic patients experience hyperglycemia in the immediate post-transplant phase. Multiple risk factors have been identified related to development of new onset diabetes after transplant, and it is estimated that upward of 7%–30% of patients will develop new onset diabetes within the first year post-transplant. There are a number of medications studied in the kidney transplant population for diabetes management, and recent data and the risks and benefits of each regimen should be optimized. Secondary hyperparathyroidism occurs in most patients with CKD and can persist after kidney transplant in up to 66% of patients, despite an initial decrease in parathyroid hormone levels. Parathyroidectomy and medical management are the options for treatment of secondary hyperparathyroidism, but there is no randomized, controlled trial providing clear recommendations for optimal management, and patient-specific factors should be considered. Obesity is the most common metabolic disorder affecting the transplant population in both the pre- and post-transplant phases of care. Not only does obesity have associations and interactions with comorbid illnesses, such as diabetes, dyslipidemia, and cardiovascular disease, all of which increase morbidity and mortality post-transplant, but it also is intimately inter-related with access to transplantation for patients with kidney failure. We review these metabolic disorders and their management, including data in patients with kidney transplants.




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RIPK3 Orchestrates Fatty Acid Metabolism in Tumor-Associated Macrophages and Hepatocarcinogenesis

Metabolic reprogramming is critical for the polarization and function of tumor-associated macrophages (TAM) and hepatocarcinogenesis, but how this reprogramming occurs is unknown. Here, we showed that receptor-interacting protein kinase 3 (RIPK3), a central factor in necroptosis, is downregulated in hepatocellular carcinoma (HCC)–associated macrophages, which correlated with tumorigenesis and enhanced the accumulation and polarization of M2 TAMs. Mechanistically, RIPK3 deficiency in TAMs reduced reactive oxygen species and significantly inhibited caspase1-mediated cleavage of PPAR. These effects enabled PPAR activation and facilitated fatty acid metabolism, including fatty acid oxidation (FAO), and induced M2 polarization in the tumor microenvironment. RIPK3 upregulation or FAO blockade reversed the immunosuppressive activity of TAMs and dampened HCC tumorigenesis. Our findings provide molecular basis for the regulation of RIPK3-mediated, lipid metabolic reprogramming of TAMs, thus highlighting a potential strategy for targeting the immunometabolism of HCC.




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IL1{alpha} Antagonizes IL1{beta} and Promotes Adaptive Immune Rejection of Malignant Tumors

We assessed the contribution of IL1 signaling molecules to malignant tumor growth using IL1β–/–, IL1α–/–, and IL1R1–/– mice. Tumors grew progressively in IL1R–/– and IL1α–/– mice but were often absent in IL1β–/– mice. This was observed whether tumors were implanted intradermally or injected intravenously and was true across multiple distinct tumor lineages. Antibodies to IL1β prevented tumor growth in wild-type (WT) mice but not in IL1R1–/– or IL1α–/– mice. Antibodies to IL1α promoted tumor growth in IL1β–/– mice and reversed the tumor-suppressive effect of anti-IL1β in WT mice. Depletion of CD8+ T cells and blockade of lymphocyte mobilization abrogated the IL1β–/– tumor suppressive effect, as did crossing IL1β–/– mice to SCID or Rag1–/– mice. Finally, blockade of IL1β synergized with blockade of PD-1 to inhibit tumor growth in WT mice. These results suggest that IL1β promotes tumor growth, whereas IL1α inhibits tumor growth by enhancing T-cell–mediated antitumor immunity.




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Single-Cell Immune Competency Signatures Associate with Survival in Phase II GVAX and CRS-207 Randomized Studies in Patients with Metastatic Pancreatic Cancer

The identification of biomarkers for patient stratification is fundamental to precision medicine efforts in oncology. Here, we identified two baseline, circulating immune cell subsets associated with overall survival in patients with metastatic pancreatic cancer who were enrolled in two phase II randomized studies of GVAX pancreas and CRS-207 immunotherapy. Single-cell mass cytometry was used to simultaneously measure 38 cell surface or intracellular markers in peripheral blood mononuclear cells obtained from a phase IIa patient subcohort (N = 38). CITRUS, an algorithm for identification of stratifying subpopulations in multidimensional cytometry datasets, was used to identify single-cell signatures associated with clinical outcome. Patients with a higher abundance of CD8+CD45ROCCR7CD57+ cells and a lower abundance of CD14+CD33+CD85j+ cells had improved overall survival [median overall survival, range (days) 271, 43–1,247] compared with patients with a lower abundance of CD8+CD45ROCCR7CD57+ cells and higher abundance of CD14+CD33+CD85j+ cells (77, 24–1,247 days; P = 0.0442). The results from this prospective–retrospective biomarker analysis were validated by flow cytometry in 200 patients with pancreatic cancer enrolled in a phase IIb study (P = 0.0047). The identified immune correlates provide potential prognostic or predictive signatures that could be employed for patient stratification.




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The Role of Fnr Paralogs in Controlling Anaerobic Metabolism in the Diazotroph Paenibacillus polymyxa WLY78 [Environmental Microbiology]

Fnr is a transcriptional regulator that controls the expression of a variety of genes in response to oxygen limitation in bacteria. Genome sequencing revealed four genes (fnr1, fnr3, fnr5, and fnr7) coding for Fnr proteins in Paenibacillus polymyxa WLY78. Fnr1 and Fnr3 showed more similarity to each other than to Fnr5 and Fnr7. Also, Fnr1 and Fnr3 exhibited high similarity with Bacillus cereus Fnr and Bacillus subtilis Fnr in sequence and structures. Both the aerobically purified His-tagged Fnr1 and His-tagged Fnr3 in Escherichia coli could bind to the specific DNA promoter. Deletion analysis showed that the four fnr genes, especially fnr1 and fnr3, have significant impacts on growth and nitrogenase activity. Single deletion of fnr1 or fnr3 led to a 50% reduction in nitrogenase activity, and double deletion of fnr1 and fnr3 resulted to a 90% reduction in activity. Genome-wide transcription analysis showed that Fnr1 and Fnr3 indirectly activated expression of nif (nitrogen fixation) genes and Fe transport genes under anaerobic conditions. Fnr1 and Fnr3 inhibited expression of the genes involved in the aerobic respiratory chain and activated expression of genes responsible for anaerobic electron acceptor genes.

IMPORTANCE The members of the nitrogen-fixing Paenibacillus spp. have great potential to be used as a bacterial fertilizer in agriculture. However, the functions of the fnr gene(s) in nitrogen fixation and other metabolisms in Paenibacillus spp. are not known. Here, we found that in P. polymyxa WLY78, Fnr1 and Fnr3 were responsible for regulation of numerous genes in response to changes in oxygen levels, but Fnr5 and Fnr7 exhibited little effect. Fnr1 and Fnr3 indirectly or directly regulated many types of important metabolism, such as nitrogen fixation, Fe uptake, respiration, and electron transport. This study not only reveals the function of the fnr genes of P. polymyxa WLY78 in nitrogen fixation and other metabolisms but also will provide insight into the evolution and regulatory mechanisms of fnr in Paenibacillus.




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Two Functional Fatty Acyl Coenzyme A Ligases Affect Free Fatty Acid Metabolism To Block Biosynthesis of an Antifungal Antibiotic in Lysobacter enzymogenes [Environmental Microbiology]

In Lysobacter enzymogenes OH11, RpfB1 and RpfB2 were predicted to encode acyl coenzyme A (CoA) ligases. RpfB1 is located in the Rpf gene cluster. Interestingly, we found an RpfB1 homolog (RpfB2) outside this canonical gene cluster, and nothing is known about its functionality or mechanism. Here, we report that rpfB1 and rpfB2 can functionally replace EcFadD in the Escherichia coli fadD mutant JW1794. RpfB activates long-chain fatty acids (n-C16:0 and n-C18:0) for the corresponding fatty acyl-CoA ligase (FCL) activity in vitro, and Glu-361 plays critical roles in the catalytic mechanism of RpfB1 and RpfB2. Deletion of rpfB1 and rpfB2 resulted in significantly increased heat-stable antifungal factor (HSAF) production, and overexpression of rpfB1 or rpfB2 completely suppressed HSAF production. Deletion of rpfB1 and rpfB2 resulted in increased L. enzymogenes diffusible signaling factor 3 (LeDSF3) synthesis in L. enzymogenes. Overall, our results showed that changes in intracellular free fatty acid levels significantly altered HSAF production. Our report shows that intracellular free fatty acids are required for HSAF production and that RpfB affects HSAF production via FCL activity. The global transcriptional regulator Clp directly regulated the expression of rpfB1 and rpfB2. In conclusion, these findings reveal new roles of RpfB in antibiotic biosynthesis in L. enzymogenes.

IMPORTANCE Understanding the biosynthetic and regulatory mechanisms of heat-stable antifungal factor (HSAF) could improve the yield in Lysobacter enzymogenes. Here, we report that RpfB1 and RpfB2 encode acyl coenzyme A (CoA) ligases. Our research shows that RpfB1 and RpfB2 affect free fatty acid metabolism via fatty acyl-CoA ligase (FCL) activity to reduce the substrate for HSAF synthesis and, thereby, block HSAF production in L. enzymogenes. Furthermore, these findings reveal new roles for the fatty acyl-CoA ligases RpfB1 and RpfB2 in antibiotic biosynthesis in L. enzymogenes. Importantly, the novelty of this work is the finding that RpfB2 lies outside the Rpf gene cluster and plays a key role in HSAF production, which has not been reported in other diffusible signaling factor (DSF)/Rpf-producing bacteria.




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Metabolic Acidosis and Hypoglycemia in a Child with Leigh-Like Phenotype




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Design of the {beta}3-Adrenergic Agonist Treatment in Chronic Pulmonary Hypertension Secondary to Heart Failure Trial

Combined pre-and post-capillary hypertension (CpcPH) is a relatively common complication of heart failure (HF) associated with a poor prognosis. Currently, there is no specific therapy approved for this entity. Recently, treatment with beta-3 adrenergic receptor (β3AR) agonists was able to improve pulmonary hemodynamics and right ventricular (RV) performance in a translational, large animal model of chronic PH. The authors present the design of a phase II randomized clinical trial that tests the benefits of mirabegron (a clinically available β3AR agonist) in patients with CpcPH due to HF. The effect of β3AR treatment will be evaluated on pulmonary hemodynamics, as well as clinical, biochemical, and advanced cardiac imaging parameters. (Beta3 Agonist Treatment in Chronic Pulmonary Hypertension Secondary to Heart Failure [SPHERE-HF]; NCT02775539)