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Glycoprotein 5 Is Cleaved by Cathepsin E during Porcine Reproductive and Respiratory Syndrome Virus Membrane Fusion [Virus-Cell Interactions]

Porcine reproductive and respiratory syndrome (PRRS) is a serious viral disease affecting the global swine industry. Its causative agent, PRRS virus (PRRSV), is an enveloped virus, and therefore membrane fusion between its envelope and host cell target membrane is critical for viral infection. Though much research has focused on PRRSV infection, the detailed mechanisms involved in its membrane fusion remain to be elucidated. In the present study, we performed confocal microscopy in combination with a constitutively active (CA) or dominant negative (DN) mutant, specific inhibitors, and small interfering RNAs (siRNAs), as well as multiple other approaches, to explore PRRSV membrane fusion. We first observed that PRRSV membrane fusion occurred in Rab11-recycling endosomes during early infection using labeled virions and subcellular markers. We further demonstrated that low pH and cathepsin E in Rab11-recycling endosomes are critical for PRRSV membrane fusion. Moreover, PRRSV glycoprotein 5 (GP5) is identified as being cleaved by cathepsin E during this process. Taken together, our findings provide in-depth information regarding PRRSV pathogenesis, which support a novel basis for the development of antiviral drugs and vaccines.

IMPORTANCE PRRS, caused by PRRSV, is an economically critical factor in pig farming worldwide. As PRRSV is a lipid membrane-wrapped virus, merging of the PRRSV envelope with the host cell membrane is indispensable for viral infection. However, there is a lack of knowledge on its membrane fusion. Here, we first explored when and where PRRSV membrane fusion occurs. Furthermore, we determined which host cell factors were involved in the process. Importantly, PRRSV GP5 is shown to be cleaved by cathepsin E during membrane fusion. Our work not only provides information on PRRSV membrane fusion for the first time but also deepens our understanding of the molecular mechanisms of PRRSV infection, which provides a foundation for future applications in the prevention and control of PRRS.




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Priming of Antiviral CD8 T Cells without Effector Function by a Persistently Replicating Hepatitis C-Like Virus [Pathogenesis and Immunity]

Immune-competent animal models for the hepatitis C virus (HCV) are nonexistent, impeding studies of host-virus interactions and vaccine development. Experimental infection of laboratory rats with a rodent hepacivirus isolated from Rattus norvegicus (RHV) is a promising surrogate model due to its recapitulation of HCV-like chronicity. However, several aspects of rat RHV infection remain unclear, for instance, how RHV evades host adaptive immunity to establish persistent infection. Here, we analyzed the induction, differentiation, and functionality of RHV-specific CD8 T cell responses that are essential for protection against viral persistence. Virus-specific CD8 T cells targeting dominant and subdominant major histocompatibility complex class I epitopes proliferated considerably in liver after RHV infection. These populations endured long term yet never acquired antiviral effector functions or selected for viral escape mutations. This was accompanied by the persistent upregulation of programmed cell death-1 and absent memory cell formation, consistent with a dysfunctional phenotype. Remarkably, transient suppression of RHV viremia with a direct-acting antiviral led to the priming of CD8 T cells with partial effector function, driving the selection of a viral escape variant. These data demonstrate an intrinsic abnormality within CD8 T cells primed by rat RHV infection, an effect that is governed at least partially by the magnitude of early virus replication. Thus, this model could be useful in investigating mechanisms of CD8 T cell subversion, leading to the persistence of hepatotropic pathogens such as HCV.

IMPORTANCE Development of vaccines against hepatitis C virus (HCV), a major cause of cirrhosis and cancer, has been stymied by a lack of animal models. The recent discovery of an HCV-like rodent hepacivirus (RHV) enabled the development of such a model in rats. This platform recapitulates HCV hepatotropism and viral chronicity necessary for vaccine testing. Currently, there are few descriptions of RHV-specific responses and why they fail to prevent persistent infection in this model. Here, we show that RHV-specific CD8 T cells, while induced early at high magnitude, do not develop into functional effectors capable of controlling virus. This defect was partially alleviated by short-term treatment with an HCV antiviral. Thus, like HCV, RHV triggers dysfunction of virus-specific CD8 T cells that are vital for infection resolution. Additional study of this evasion strategy and how to mitigate it could enhance our understanding of hepatotropic viral infections and lead to improved vaccines and therapeutics.




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NF-{kappa}B and Keap1 Interaction Represses Nrf2-Mediated Antioxidant Response in Rabbit Hemorrhagic Disease Virus Infection [Pathogenesis and Immunity]

The rabbit hemorrhagic disease virus (RHDV), which belongs to the family Caliciviridae and the genus Lagovirus, causes lethal fulminant hepatitis in rabbits. RHDV decreases the activity of antioxidant enzymes regulated by Nrf2 in the liver. Antioxidants are important for the maintenance of cellular integrity and cytoprotection. However, the mechanism underlying the regulation of the Nrf2-antioxidant response element (ARE) signaling pathway by RHDV remains unclear. Using isobaric tags for relative and absolute quantification (iTRAQ) technology, the current study demonstrated that RHDV inhibits the induction of ARE-regulated genes and increases the expression of the p50 subunit of the NF-B transcription factor. We showed that RHDV replication causes a remarkable increase in reactive oxygen species (ROS), which is simultaneously accompanied by a significant decrease in Nrf2. It was found that nuclear translocation of Keap1 plays a key role in the nuclear export of Nrf2, leading to the inhibition of Nrf2 transcriptional activity. The p50 protein partners with Keap1 to form the Keap1-p50/p65 complex, which is involved in the nuclear translocation of Keap1. Moreover, upregulation of Nrf2 protein levels in liver cell nuclei by tert-butylhydroquinone (tBHQ) delayed rabbit deaths due to RHDV infection. Considered together, our findings suggest that RHDV inhibits the Nrf2-dependent antioxidant response via nuclear translocation of Keap1-NF-B complex and nuclear export of Nrf2 and provide new insight into the importance of oxidative stress during RHDV infection.

IMPORTANCE Recent studies have reported that rabbit hemorrhagic disease virus (RHDV) infection reduced Nrf2-related antioxidant function. However, the regulatory mechanisms underlying this process remain unclear. The current study showed that the NF-B p50 subunit partners with Keap1 to form the Keap1-NF-B complex, which plays a key role in the inhibition of Nrf2 transcriptional activity. More importantly, upregulated Nrf2 activity delayed the death of RHDV-infected rabbits, strongly indicating the importance of oxidative damage during RHDV infection. These findings may provide novel insights into the pathogenesis of RHDV.




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Sample multiplexing for targeted pathway proteomics in aging mice [Systems Biology]

Pathway proteomics strategies measure protein expression changes in specific cellular processes that carry out related functions. Using targeted tandem mass tags-based sample multiplexing, hundreds of proteins can be quantified across 10 or more samples simultaneously. To facilitate these highly complex experiments, we introduce a strategy that provides complete control over...




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Transposon mobilization in the human fungal pathogen Cryptococcus is mutagenic during infection and promotes drug resistance in vitro [Microbiology]

When transitioning from the environment, pathogenic microorganisms must adapt rapidly to survive in hostile host conditions. This is especially true for environmental fungi that cause opportunistic infections in immunocompromised patients since these microbes are not well adapted human pathogens. Cryptococcus species are yeastlike fungi that cause lethal infections, especially in...




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Triptolide suppresses IDH1-mutated malignancy via Nrf2-driven glutathione metabolism [Medical Sciences]

Isocitrate dehydrogenase (IDH) mutation is a common genetic abnormality in human malignancies characterized by remarkable metabolic reprogramming. Our present study demonstrated that IDH1-mutated cells showed elevated levels of reactive oxygen species and higher demands on Nrf2-guided glutathione de novo synthesis. Our findings showed that triptolide, a diterpenoid epoxide from Tripterygium...




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MTV proteins unveil ER- and microtubule-associated compartments in the plant vacuolar trafficking pathway [Cell Biology]

The factors and mechanisms involved in vacuolar transport in plants, and in particular those directing vesicles to their target endomembrane compartment, remain largely unknown. To identify components of the vacuolar trafficking machinery, we searched for Arabidopsis modified transport to the vacuole (mtv) mutants that abnormally secrete the synthetic vacuolar cargo...




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Mimicry of a biophysical pathway leads to diverse pollen-like surface patterns [Applied Physical Sciences]

A ubiquitous structural feature in biological systems is texture in extracellular matrix that gains functions when hardened, for example, cell walls, insect scales, and diatom tests. Here, we develop patterned liquid crystal elastomer (LCE) particles by recapitulating the biophysical patterning mechanism that forms pollen grain surfaces. In pollen grains, a...




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SARS-CoV-2 and ORF3a: Nonsynonymous Mutations, Functional Domains, and Viral Pathogenesis

ABSTRACT

The effect of the rapid accumulation of nonsynonymous mutations on the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not yet known. The 3a protein is unique to SARS-CoV and is essential for disease pathogenesis. Our study aimed at determining the nonsynonymous mutations in the 3a protein in SARS-CoV-2 and determining and characterizing the protein’s structure and spatial orientation in comparison to those of 3a in SARS-CoV. A total of 51 different nonsynonymous amino acid substitutions were detected in the 3a proteins among 2,782 SARS-CoV-2 strains. We observed microclonality within the ORF3a gene tree defined by nonsynonymous mutations separating the isolates into distinct subpopulations. We detected and identified six functional domains (I to VI) in the SARS-CoV-2 3a protein. The functional domains were linked to virulence, infectivity, ion channel formation, and virus release. Our study showed the importance of conserved functional domains across the species barrier and revealed the possible role of the 3a protein in the viral life cycle. Observations reported in this study merit experimental confirmation.

IMPORTANCE At the surge of the coronavirus disease 2019 (COVID-19) pandemic, we detected and identified six functional domains (I to VI) in the SARS-CoV-2 3a protein. Our analysis showed that the functional domains were linked to virulence, infectivity, ion channel formation, and virus release in SARS-CoV-2 3a. Our study also revealed the functional importance of conserved domains across the species barrier. Observations reported in this study merit experimental confirmation.




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Re: Abnormally Low Hemoglobin A1c as Harbinger of Hemoglobinopathy




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Cervical Spondylotic Myelopathy: A Guide to Diagnosis and Management

Cervical spondylotic myelopathy (CSM) is a neurologic condition that develops insidiously over time as degenerative changes of the spine result in compression of the cord and nearby structures. It is the most common form of spinal cord injury in adults; yet, its diagnosis is often delayed. The purpose of this article is to review the pathophysiology, natural history, diagnosis, and management of CSM with a focus on the recommended timeline for physicians suspecting CSM to refer patients to a spine surgeon. Various processes underlie spondylotic changes of the canal and are separated into static and dynamic factors. Not all patients with evidence of cord compression will present with symptoms, and the progression of disease varies by patient. The hallmark symptoms of CSM include decreased hand dexterity and gait instability as well as sensory and motor dysfunction. magnetic resonance imaging is the imaging modality of choice in patients with suspected CSM, but computed tomography myelography may be used in patients with contraindications. Patients with mild CSM may be treated surgically or nonoperatively, whereas those with moderate-severe disease are treated operatively. Due to the long-term disability that may result from a delay in diagnosis and management, prompt referral to a spine surgeon is recommended for any patient suspected of having CSM. This review provides information and guidelines for practitioners to develop an actionable awareness of CSM.




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Chitotriosidase as a Novel Biomarker for Therapeutic Monitoring of Nephropathic Cystinosis

Background

Nephropathic cystinosis, a hereditary lysosomal storage disorder caused by dysfunction of the lysosomal cotransporter cystinosin, leads to cystine accumulation and cellular damage in various organs, particularly in the kidney. Close therapeutic monitoring of cysteamine, the only available disease-modifying treatment, is recommended. White blood cell cystine concentration is the current gold standard for therapeutic monitoring, but the assay is technically demanding and is available only on a limited basis. Because macrophage-mediated inflammation plays an important role in the pathogenesis of cystinosis, biomarkers of macrophage activation could have potential for the therapeutic monitoring of cystinosis.

Methods

We conducted a 2-year prospective, longitudinal study in which 61 patients with cystinosis who were receiving cysteamine therapy were recruited from three European reference centers. Each regular care visit included measuring four biomarkers of macrophage activation: IL-1β, IL-6, IL-18, and chitotriosidase enzyme activity.

Results

A multivariate linear regression analysis of the longitudinal data for 57 analyzable patients found chitotriosidase enzyme activity and IL-6 to be significant independent predictors for white blood cell cystine levels in patients of all ages with cystinosis; a receiver operating characteristic analysis ranked chitotriosidase as superior to IL-6 in distinguishing good from poor therapeutic control (on the basis of white blood cell cystine levels of <2 nmol 1/2 cystine/mg protein or ≥2 nmol 1/2 cystine/mg protein, respectively). Moreover, in patients with at least one extrarenal complication, chitotriosidase significantly correlated with the number of extrarenal complications and was superior to white blood cell cystine levels in predicting the presence of multiple extrarenal complications.

Conclusions

Chitotriosidase enzyme activity holds promise as a biomarker for use in therapeutic monitoring of nephropathic cystinosis.




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PIWI-piRNA pathway-mediated transposable element repression in Hydra somatic stem cells [REPORT]

Transposable elements (TEs) can damage genomes, thus organisms use a variety of mechanisms to repress TE expression. The PIWI–piRNA pathway is a small RNA pathway that represses TE expression in the germline of animals. Here we explore the function of the pathway in the somatic stem cells of Hydra, a long-lived freshwater cnidarian. Hydra have three stem cell populations, all of which express PIWI proteins; endodermal and ectodermal epithelial stem cells (ESCs) are somatic, whereas the interstitial stem cells have germline competence. To study somatic function of the pathway, we isolated piRNAs from Hydra that lack the interstitial lineage and found that these somatic piRNAs map predominantly to TE transcripts and display the conserved sequence signatures typical of germline piRNAs. Three lines of evidence suggest that the PIWI–piRNA pathway represses TEs in Hydra ESCs. First, epithelial knockdown of the Hydra piwi gene hywi resulted in up-regulation of TE expression. Second, degradome sequencing revealed evidence of PIWI-mediated cleavage of TE RNAs in epithelial cells using the ping-pong mechanism. Finally, we demonstrated a direct association between Hywi protein and TE transcripts in epithelial cells using RNA immunoprecipitation. Altogether, our data reveal that the PIWI–piRNA pathway represses TE expression in the somatic cell lineages of Hydra, which we propose contributes to the extreme longevity of the organism. Furthermore, our results, in combination with others, suggest that somatic TE repression is an ancestral function of the PIWI–piRNA pathway.




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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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{alpha}-Synuclein filaments from transgenic mouse and human synucleinopathy-containing brains are ma&#x0237;or seed-competent species [Molecular Bases of Disease]

Assembled α-synuclein in nerve cells and glial cells is the defining pathological feature of neurodegenerative diseases called synucleinopathies. Seeds of α-synuclein can induce the assembly of monomeric protein. Here, we used sucrose gradient centrifugation and transiently transfected HEK 293T cells to identify the species of α-synuclein from the brains of homozygous, symptomatic mice transgenic for human mutant A53T α-synuclein (line M83) that seed aggregation. The most potent fractions contained Sarkosyl-insoluble assemblies enriched in filaments. We also analyzed six cases of idiopathic Parkinson's disease (PD), one case of familial PD, and six cases of multiple system atrophy (MSA) for their ability to induce α-synuclein aggregation. The MSA samples were more potent than those of idiopathic PD in seeding aggregation. We found that following sucrose gradient centrifugation, the most seed-competent fractions from PD and MSA brains are those that contain Sarkosyl-insoluble α-synuclein. The fractions differed between PD and MSA, consistent with the presence of distinct conformers of assembled α-synuclein in these different samples. We conclude that α-synuclein filaments are the main driving force for amplification and propagation of pathology in synucleinopathies.




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Targeting the polyamine pathway&#x2014;&#x201C;a means&#x201D; to overcome chemoresistance in triple-negative breast cancer [Cell Biology]

Triple-negative breast cancer (TNBC) is characterized by its aggressive biology, early metastatic spread, and poor survival outcomes. TNBC lacks expression of the targetable receptors found in other breast cancer subtypes, mandating use of cytotoxic chemotherapy. However, resistance to chemotherapy is a significant problem, encountered in about two-thirds of TNBC patients, and new strategies are needed to mitigate resistance. In this issue of the Journal of Biological Chemistry, Geck et al. report that TNBC cells are highly sensitive to inhibition of the de novo polyamine synthesis pathway and that inhibition of this pathway sensitizes cells to TNBC-relevant chemotherapy, uncovering new opportunities for addressing chemoresistance.




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Pathogenesis and Management of Indirect Hyperbilirubinemia in Preterm Neonates Less Than 35 Weeks: Moving Toward a Standardized Approach

Premature infants have a higher incidence of indirect hyperbilirubinemia than term infants. Management of neonatal indirect hyperbilirubinemia in late preterm and term neonates has been well addressed by recognized, consensus-based guidelines. However, the extension of these guidelines to the preterm population has been an area of uncertainty because of limited evidence. This leads to variation in clinical practice and lack of recognition of the spectrum of bilirubin-induced neurologic dysfunction (BIND) in this population. Preterm infants are metabolically immature and at higher risk for BIND at lower bilirubin levels than their term counterparts. Early use of phototherapy to eliminate BIND and minimize the need for exchange transfusion is the goal of treatment in premature neonates. Although considered relatively safe, phototherapy does have side effects, and some NICUs tend to overuse phototherapy. In this review, we describe the epidemiology and pathophysiology of BIND in preterm neonates, and discuss our approach to standardized management of indirect hyperbilirubinemia in the vulnerable preterm population. The proposed treatment charts suggest early use of phototherapy in preterm neonates with the aim of reducing exposure to high irradiance levels, minimizing the need for exchange transfusions, and preventing BIND. The charts are pragmatic and have additional curves for stopping phototherapy and escalating its intensity. Having a standardized approach would support future research and quality improvement initiatives that examine dose and duration of phototherapy exposure with relation to outcomes.




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Cyclical variations of fluid sources and stress state in a shallow megathrust-zone melange

Differences in REE patterns of calcite from extensional and shear veins of the Sestola Vidiciatico Tectonic Unit in the Northern Apennines suggest variations in fluid source during the seismic cycle in an ancient analogue of a shallow megathrust (Tmax c. 100–150°C). In shear veins, a positive Eu anomaly suggests an exotic fluid source, probably hotter than the fault environment. Small-scale extensional veins were derived instead from a local fluid in equilibrium with the fault rocks. Mutually crosscutting relations between two extensional vein sets, parallel and perpendicular to the megathrust, suggest repeated shifting of the 1 and 3 stresses during the seismic cycle. This is consistent with: (1) a seismic phase, with brittle failure along the thrust, crystallization of shear veins from an exotic fluid, stress drop and stress rotation; (2) a post-seismic phase, with fault-normal compaction and formation of fault-normal extensional veins fed by local fluids; (3) a reloading phase, where shear stress and pore pressure are gradually restored and fault-parallel extensional veins form, until the thrust fails again. The combination of geochemical and structural analyses in veins from exhumed megathrust analogues represents a promising tool to better understand the interplay between stress state and fluids in modern subduction zones.

Supplementary material: Cathodoluminescence microphotographs, methodological details of the microstructural analysis, microphotographs of the location of analysed spots and a geochemical data table are available at https://doi.org/10.6084/m9.figshare.c.4842165

Thematic collection: This article is part of the Polygenetic mélanges collection available at: https://www.lyellcollection.org/cc/polygenetic-melanges




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Sedimentary and diapiric melanges in the Skrzydlna area (Outer Carpathians of Poland) as indicators of basinal and structural evolution

The Dukla Nappe in the Skrzydlna area exposes two types of mélange reflecting two different phases of basinal and tectonic evolution of the Outer West Carpathian orogen in its Polish sector. The Oligocene-age sedimentary mélange (olistostrome) is related to growth of the accretionary wedge, whereas the Miocene-age diapiric mélange postdates the orogenic thrusting. Textural and structural features of the very coarse-grained sedimentary mélange suggest non-cohesive debris flows and high-density turbidity currents as predominant emplacement mechanisms. Growth strata, associated with progressive unconformities, and facies contrast between the underlying fine-grained unit and the overlying olistostrome reflect a considerable uplift of the source area and rotation of the adjacent part of the basin floor. The olistostrome and the overlying turbidite succession form a retrogressive sequence interpreted as a submarine canyon infill grading to a small submarine fan. The diapiric mélange, injected into the Oligocene-age succession of the Dukla Nappe, contains the Early and Late Cretaceous-age blocks and matrix derived from the underlying Silesian Nappe. The features reflecting diapiric emplacement include matrix proportion increase and block content decrease towards the mélange margins, scaly fabric and shear zones. Both mélanges, interpreted in the past as chaotic bodies, upon detailed examination reveal genesis-related subtle internal organization.




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Weathering history and landscape evolution of Western Ghats (India) from 40Ar/39Ar dating of supergene K-Mn oxides

Laterites preserved on both sides of the Western Ghats Escarpment of Peninsular India have formed by long-term lateritic weathering essentially after India–Seychelles continental break-up following Deccan Traps emplacement (c. 63 myr ago). Supergene manganese ores of the Western Ghats were formed on Late Archean manganese protores. Among Mn oxides composing the ores, cryptomelane (K-rich Mn oxide) was characterized and dated by 40Ar/39Ar geochronology. Measured ages complement those previously obtained in other South Indian manganese ores from the hinterland plateau and further document three major weathering periods, c. 53–44, c. 39–22 and c. 14–10 Ma, the last being documented for the first time in India. These periods coincide with global palaeoclimatic proxies and date the lateritic weathering of three successive palaeolandscapes of the Western Ghats that evolved under slow denudation (c. 8 m Ma–1) over the last 44 myr and were mostly incised during the Neogene (<22 Ma). This indicates that the Western Ghats are a relict of a South Indian plateau preserved at the headwaters of very long east-flowing river systems and above the Western Ghats Escarpment. Topography and denudation history of this landscape do not require Neogene tilt of the Peninsula as recently proposed.

Supplementary material: Full details of field and sample description, methods and analytical data including electron probe microanalyses of cryptomelane, and isotopic analyses and degassing spectra of irradiated cryptomelane grains are available at https://doi.org/10.6084/m9.figshare.c.4726661




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Paleomagnetic and magnetic fabric data from Lower Triassic redbeds of the Central Western Carpathians: new constraints on the paleogeographic and tectonic evolution of the Carpathian region

In the Central Western Carpathians (CWC), most published paleomagnetic results from Permo-Mesozoic rocks document extensive remagnetizations and come from thin-skinned thrust units that have undergone multistage deformation. We present results from lower Triassic redbeds from the autochthonous cover overlying the basement that carry a primary magnetization. Petromagnetic results indicate that the dominant ferromagnetic carrier is hematite, while magnetic susceptibility and its anisotropy are controlled by both ferromagnetic and paramagnetic minerals. Magnetic fabrics document weak deformation related to Late Cretaceous shortening. The directions of the high unblocking temperature remanence components pass both reversal and fold tests, attesting to their primary nature. Paleomagnetic inclinations are flatter than expected from reference datasets, suggesting small latitudinal separation between the CWC and stable Europe. Paleomagnetic declinations are mostly clustered within individual mountain massifs, implying their tectonic coherence. They show only minor differences between the massifs, indicating a lack of significant vertical-axis tectonic rotations within the studied central parts of the CWC. The paleomagnetic declinations are therefore representative of the whole of the CWC in terms of regional paleogeographic interpretations, and imply moderate counterclockwise rotations (c. 26°) of the region with respect to stable Europe since the Early Triassic.




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Geochronology and geochemistry of the Tabaquito batholith (Frontal Cordillera, Argentina): geodynamic implications and temporal correlations in the SW Gondwana margin

The Tabaquito batholith (Frontal Cordillera, western Argentina), is mainly composed of shallowly emplaced granodiorite to minor monzogranite with abundant mafic microgranular enclaves. New sensitive high-resolution ion microprobe U–Pb zircon ages of c. 337 Ma (biotite granodiorite) and c. 284 Ma (mafic dyke) along with previously published geochronological data suggest that a long-lived magmatic system formed through at least two magmatic pulses at c. 337 and c. 322 Ma with later superimposition of Permian magmatism. The Tabaquito granitoids are metaluminous, calc-alkalic and magnesian with I-type affinity. Elevated Th/Nb, Y/Nb and La/Nb ratios along with negative Nb–Ta and positive Pb anomalies are consistent with a continental arc setting. Hf, Nd and Sr isotopic composition of the Tabaquito granitoids suggests that their source could result from mixing of an old felsic crustal component and a juvenile mafic to intermediate component. New geochronological and geochemical data together with published data reveal a continuous arc setting from the Carboniferous to the Permian in Argentina, and important magmatic compositional variations through time and space controlled by episodic fluctuations in the subduction angle of the oceanic plate. Reported and compiled data allow us to infer the continuity of the Carboniferous magmatic arc along the west margin of Gondwana.

Supplementary material: Detailed petrography, analytical methods and data, zircon cathodoluminescence images and supplementary figures are available at https://doi.org/10.6084/m9.figshare.c.4763993




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Clinical and MRI phenotypes of sarcoidosis-associated myelopathy

Objective

To determine the characteristic clinical and spinal MRI phenotypes of sarcoidosis-associated myelopathy (SAM), we analyzed a large cohort of patients with this disorder.

Methods

Patients diagnosed with SAM at a single center between 2000 and 2018 who met the established criteria for definite and probable neurosarcoidosis were included in a retrospective analysis to identify clinical profiles, CSF characteristics, and MRI lesion morphology.

Results

Of 62 included patients, 33 (53%) were male, and 30 (48%) were African American. SAM was the first clinical presentation of sarcoidosis in 49 patients (79%). Temporal profile of symptom evolution was chronic in 81%, with sensory symptoms most frequently reported (87%). CSF studies showed pleocytosis in 79% and CSF-restricted oligoclonal bands in 23% of samples tested. Four discrete patterns of lesion morphology were identified on spine MRI: longitudinally extensive myelitis (n = 28, 45%), short tumefactive myelitis (n = 14, 23%), spinal meningitis/meningoradiculitis (n = 14, 23%), and anterior myelitis associated with areas of disc degeneration (n = 6, 10%). Postgadolinium enhancement was seen in all but 1 patient during the acute phase. The most frequent enhancement pattern was dorsal subpial enhancement (n = 40), followed by meningeal/radicular enhancement (n = 23) and ventral subpial enhancement (n = 12). In 26 cases (42%), enhancement occurred at locations with coexisting structural changes (e.g., spondylosis).

Conclusions

Recognition of the clinical features (chronically evolving myelopathy) and distinct MRI phenotypes (with enhancement in a subpial and/or meningeal pattern) seen in SAM can aid diagnosis of this disorder. Enhancement patterns suggest that SAM may have a predilection for areas of the spinal cord susceptible to mechanical stress.




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Guillain-Barre syndrome and chronic inflammatory demyelinating polyradiculoneuropathy after alemtuzumab therapy in kidney transplant recipients

Alemtuzumab is approved for the treatment of relapsing-remitting MS and is used off-label for patients with chronic lymphocytic leukemia and as induction and antirejection therapy in kidney transplant recipients.1 Guillain-Barré syndrome (GBS) or chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) complicating alemtuzumab treatment was reported in 9 patients with hematologic malignancy or MS.1–3 The risk of GBS or CIDP in solid organ transplant recipients treated with alemtuzumab is unknown.




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The Bruton tyrosine kinase inhibitor ibrutinib improves anti-MAG antibody polyneuropathy

Objective

To assess whether neuropathy with anti-myelin-associated glycoprotein (MAG) antibody may improve after treatment with ibrutinib, an oral inhibitor of Bruton tyrosine kinase, we prospectively treated with ibrutinib a cohort of 3 patients with anti-MAG neuropathy and Waldenström macroglobulinemia (WM).

Methods

All 3 patients underwent bone marrow biopsy showing WM, with MYD88L265P mutated and CXCR4S338X wild type, and were started on ibrutinib 420 mg/die. Patients were assessed at baseline, at 3-6-9 months, and at 12 months in 2 patients with a longer follow-up, using Inflammatory Neuropathy Cause and Treatment (INCAT) Disability Score, INCAT sensory sum score, and Medical Research Council sum score. The modified International Cooperative Ataxia Rating Scale was performed in 2 patients, whereas it was not used in the patient with Parkinson disease as a major comorbidity. Responders were considered the patients improving by at least one point in 2 clinical scales.

Results

All the patients reported an early and subjective benefit, consistent with the objective improvement, especially of the sensory symptoms as shown by clinical scales. Treatment was well tolerated.

Conclusion

These preliminary data point to a possible efficacy of ibrutinib in anti-MAG antibody neuropathy, which is the most common disabling paraproteinemic neuropathy, where active treatment is eagerly needed.

Classification of evidence

This study provides Class IV evidence that for patients with anti-MAG antibody neuropathy, ibrutinib improves neuropathy symptoms.




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Multicenter Evaluation of a PCR-Based Digital Microfluidics and Electrochemical Detection System for the Rapid Identification of 15 Fungal Pathogens Directly from Positive Blood Cultures [Mycology]

Routine identification of fungal pathogens from positive blood cultures by culture-based methods can be time-consuming, delaying treatment with appropriate antifungal agents. The GenMark Dx ePlex investigational use only blood culture identification fungal pathogen panel (BCID-FP) rapidly detects 15 fungal targets simultaneously in blood culture samples positive for fungi by Gram staining. We aimed to determine the performance of the BCID-FP in a multicenter clinical study. Blood culture samples collected at 10 United States sites and tested with BCID-FP at 4 sites were compared to the standard-of-care microbiological and biochemical techniques, fluorescence in situ hybridization using peptide nucleic acid probes (PNA-FISH) and matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). Discrepant results were analyzed by bi-directional PCR/sequencing of residual blood culture samples. A total of 866 clinical samples, 120 retrospectively and 21 prospectively collected, along with 725 contrived samples were evaluated. Sensitivity and specificity of detection of Candida species (C. albicans, C. auris, C. dubliniensis, C. famata, C. glabrata, C. guilliermondii, C. kefyr, C. krusei, C. lusitaniae, C. parapsilosis, and C. tropicalis) ranged from 97.1 to 100% and 99.8 to 100%, respectively. For the other organism targets, sensitivity and specificity were as follows: 100% each for Cryptococcus neoformans and C. gattii, 98.6% and 100% for Fusarium spp., and 96.2% and 99.9% for Rhodotorula spp., respectively. In 4 of the 141 clinical samples, the BCID-FP panel correctly identified an additional Candida species, undetected by standard-of-care methods. The BCID-FP panel offers a faster turnaround time for identification of fungal pathogens in positive blood cultures that may allow for earlier antifungal interventions and includes C. auris, a highly multidrug-resistant fungus.




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Pathogen or Bystander: Clinical Significance of Detecting Human Herpesvirus 6 in Pediatric Cerebrospinal Fluid [Virology]

Human herpesvirus 6 (HHV-6) is an important cause of meningitis and meningoencephalitis. As testing for HHV-6 in cerebrospinal fluid (CSF) is more readily available using the FilmArray Meningitis/Encephalitis panel (FA-ME; BioFire Diagnostics, Salt Lake City, UT), we aimed to determine the clinical significance of detecting HHV-6 in order to identify true infections and to ensure appropriate antiviral initiation. Chart review on 25 patients positive for HHV-6 by FA-ME was performed to determine clinical presentation, comorbidity, treatment, and outcome. The presence of chromosomally integrated HHV-6 (ciHHV-6) DNA was also investigated. Of 1,005 children tested by FA-ME, HHV-6 was detected in 25 (2.5%). Five patients were diagnosed with either HHV-6 meningitis or meningoencephalitis based on HHV-6 detection in CSF, clinical presentation, and radiographic findings. Detection of HHV-6 by FA-ME led to discontinuation of acyclovir within 12.0 h in all 12 patients empirically treated with acyclovir. Six of the 12 patients were started on ganciclovir therapy within 6.8 h; 4 of these were treated specifically for HHV-6 infection, whereas therapy was discontinued in the remaining 2 patients. CSF parameters were not generally predictive of HHV-6 positivity. The presence of ciHHV-6 was confirmed in 3 of 18 patients who could be tested. Five of the 25 patients included in the study were diagnosed with HHV-6 meningitis/meningoencephalitis. FA-ME results led to discontinuation of empirical antiviral treatment in 12 patients and appropriate initiation of ganciclovir in 4 patients. In our institution, detection of HHV-6 using FA-ME led to faster establishment of disease etiology and optimization of antimicrobial therapy.




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Suppressor mutations in Mecp2-null mice implicate the DNA damage response in Rett syndrome pathology [RESEARCH]

Mutations in X-linked methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome (RTT). To identify functional pathways that could inform therapeutic entry points, we carried out a genetic screen for secondary mutations that improved phenotypes in Mecp2/Y mice after mutagenesis with N-ethyl-N-nitrosourea (ENU). Here, we report the isolation of 106 founder animals that show suppression of Mecp2-null traits from screening 3177 Mecp2/Y genomes. Whole-exome sequencing, genetic crosses, and association analysis identified 22 candidate genes. Additional lesions in these candidate genes or pathway components associate variant alleles with phenotypic improvement in 30 lines. A network analysis shows that 63% of the genes cluster into the functional categories of transcriptional repression, chromatin modification, or DNA repair, delineating a pathway relationship with MECP2. Many mutations lie in genes that modulate synaptic signaling or lipid homeostasis. Mutations in genes that function in the DNA damage response (DDR) also improve phenotypes in Mecp2/Y mice. Association analysis was successful in resolving combinatorial effects of multiple loci. One line, which carries a suppressor mutation in a gene required for cholesterol synthesis, Sqle, carries a second mutation in retinoblastoma binding protein 8, endonuclease (Rbbp8, also known as CtIP), which regulates a DDR choice in double-stranded break (DSB) repair. Cells from Mecp2/Y mice have increased DSBs, so this finding suggests that the balance between homology-directed repair and nonhomologous end joining is important for neuronal cells. In this and other lines, two suppressor mutations confer greater improvement than one alone, suggesting that combination therapies could be effective in RTT.




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Cinnamaldehyde Inhibits Inflammation of Human Synoviocyte Cells Through Regulation of Jak/Stat Pathway and Ameliorates Collagen-Induced Arthritis in Rats [Inflammation, Immunopharmacology, and Asthma]

Cinnamaldehyde (Cin), a bioactive cinnamon essential oil from traditional Chinese medicine herb Cinnamomum cassia, has been reported to have multipharmacological activities including anti-inflammation. However, its role and molecular mechanism of anti-inflammatory activity in musculoskeletal tissues remains unclear. Here, we first investigated the effects and molecular mechanisms of Cin in human synoviocyte cells. Then in vivo therapeutic effect of Cin on collagen-induced arthritis (CIA) also studied. Cell Counting Kit ‎CCK-8 assay was performed to evaluate the cell cytotoxicity. Proinflammatory cytokine expression was evaluated using quantitative polymerase chain reaction and ELISA. Protein expression was measured by western blotting. The in vivo effect of Cin (75 mg/kg per day) was evaluated in rats with CIA by gavage administration. Disease progression was assessed by clinical scoring, radiographic, and histologic examinations. Cin significantly inhibited interleukin (IL)-1β–induced IL-6, IL-8, and tumor necrosis factor-α release from human synoviocyte cells. The molecular analysis revealed that Cin impaired IL-6–induced activation of Janus kinase 2 (JAK2), signal transducer and activator of transcription 1 (STAT1), and STAT3 signaling pathway by inhibiting the phosphorylation of JAK2, STAT1, and STAT3, without affecting NF-B pathway. Cin reduced collagen-induced swollen paw volume of arthritic rats. The anti-inflammation effects of Cin were associated with decreased severity of arthritis, joint swelling, and reduced bone erosion and destruction. Furthermore, serum IL-6 level was decreased when Cin administered therapeutically to CIA rats. Cin suppresses IL-1β–induced inflammation in synoviocytes through the JAK/STAT pathway and alleviated collagen-induced arthritis in rats. These data indicated that Cin might be a potential traditional Chinese medicine–derived, disease-modifying, antirheumatic herbal drug.

SIGNIFICANCE STATEMENT

In this study, we found that cinnamaldehyde (Cin) suppressed proinflammatory cytokines secretion in rheumatology arthritis synoviocyte cells by Janus kinase/signal transducer and activator of transcription pathway. The in vivo results showed that Cin ameliorated collagen-induced arthritis in rats. These findings indicate that Cin is a potential traditional Chinese medicine–derived, disease-modifying, antirheumatic herbal drug.




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Inner Ear Arginine Vasopressin-Vasopressin Receptor 2-Aquaporin 2 Signaling Pathway Is Involved in the Induction of Motion Sickness [Drug Discovery and Translational Medicine]

It has been identified that arginine vasopressin (AVP), vasopressin receptor 2(V2R), and the aquaporin 2 (AQP2) signaling pathway in the inner ear play important roles in hearing and balance functions through regulating the endolymph equilibrium; however, the contributions of this signaling pathway to the development of motion sickness are unclear. The present study was designed to investigate whether the activation of the AVP-V2R-AQP2 signaling pathway in the inner ear is involved in the induction of motion sickness and whether mozavaptan, a V2R antagonist, could reduce motion sickness. We found that both rotatory stimulus and intraperitoneal AVP injection induced conditioned taste aversion (a confirmed behavioral index for motion sickness) in rats and activated the AVP-V2R-AQP2 signaling pathway with a responsive V2R downregulation in the inner ears, and AVP perfusion in cultured epithelial cells from rat endolymphatic sacs induced similar changes in this pathway signaling. Vestibular training, V2R antagonist mozavaptan, or PKA inhibitor H89 blunted these changes in the V2R-AQP2 pathway signaling while reducing rotatory stimulus– or DDAVP (a V2R agonist)-induced motion sickness in rats and dogs. Therefore, our results suggest that activation of the inner ear AVP-V2R-AQP2 signaling pathway is potentially involved in the development of motion sickness; thus, mozavaptan targeting AVP V2Rs in the inner ear may provide us with a new application option to reduce motion sickness.

SIGNIFICANCE STATEMENT

Motion sickness affects many people traveling or working. In the present study our results showed that activation of the inner ear arginine vasopressin-vaspopressin receptor 2 (V2R)-aquaporin 2 signaling pathway was potentially involved in the development of motion sickness and that blocking V2R with mozavaptan, a V2R antagonist, was much more effective in reducing motion sickness in both rat and dog; therefore, we demonstrated a new mechanism to underlie motion sickness and a new candidate drug to reduce motion sickness.




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The mammalian cytosolic thioredoxin reductase pathway acts via a membrane protein to reduce ER-localised proteins [RESEARCH ARTICLE]

Xiaofei Cao, Sergio Lilla, Zhenbo Cao, Marie Anne Pringle, Ojore B. V. Oka, Philip J. Robinson, Tomasz Szmaja, Marcel van Lith, Sara Zanivan, and Neil J. Bulleid

Folding of proteins entering the mammalian secretory pathway requires the insertion of the correct disulfides. Disulfide formation involves both an oxidative pathway for their insertion and a reductive pathway to remove incorrectly formed disulfides. Reduction of these disulfides is crucial for correct folding and degradation of misfolded proteins. Previously, we showed that the reductive pathway is driven by NADPH generated in the cytosol. Here, by reconstituting the pathway using purified proteins and ER microsomal membranes, we demonstrate that the thioredoxin reductase system provides the minimal cytosolic components required for reducing proteins within the ER lumen. In particular, saturation of the pathway and its protease sensitivity demonstrates the requirement for a membrane protein to shuttle electrons from the cytosol to the ER. These results provide compelling evidence for the crucial role of the cytosol in regulating ER redox homeostasis, ensuring correct protein folding and facilitating the degradation of misfolded ER proteins.




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FAK regulates actin polymerization during sperm capacitation via the ERK2/GEF-H1/RhoA signaling pathway [RESEARCH ARTICLE]

Monica L. Salgado-Lucio, Danelia Ramirez-Ramirez, Coral Y. Jorge-Cruz, Ana L. Roa-Espitia, and Enrique O. Hernandez-Gonzalez

Actin polymerization is a crucial process during sperm capacitation. We have recently described the participation of FAK during actin polymerization in guinea pig spermatozoa. However, the mechanism by which FAK mediates these processes is unknown. Our previous data have shown that MAPK1 (hereafter referred to as ERK2) is activated during the first minutes of capacitation, and inhibition of ERK2 blocked actin polymerization and the acrosome reaction. In this current study, we found that FAK is involved in ERK2 activation – as FAK was phosphorylated at tyrosine residue 925 and bound to Grb2 – and that inhibition of FAK results in a significant decrease of ERK2 activation. We also confirmed the presence of Rho guanine nucleotide exchange factor 2 (ARHGEF2, hereafter referred to as GEF-H1), which is able to associate with RhoA during capacitation. RhoA activation and its participation in actin polymerization were also analyzed. Inhibition of FAK or ERK1/2 impeded GEF-H1 phosphorylation, RhoA activation, and the association between GEF-H1 and RhoA. Finally, we observed the presence of fibronectin on the sperm surface, its role in sperm–sperm interaction as well as participation of β-integrin in the activation of ERK2. Our results show that the signaling pathway downstream of fibronectin, via integrin, FAK, Grb2, MEK1/2, ERK2, GEF-H1 and RhoA regulates the actin polymerization associated with spermatozoa capacitation.




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Imaging Inflammation in Atherosclerosis with CXCR4-Directed 68Ga-Pentixafor PET/CT: Correlation with 18F-FDG PET/CT

C-X-C motif chemokine receptor 4 (CXCR4) is expressed on the surface of various cell types involved in atherosclerosis, with a particularly rich receptor expression on macrophages and T cells. First pilot studies with 68Ga-pentixafor, a novel CXCR4-directed PET tracer, have shown promise to noninvasively image inflammation within atherosclerotic plaques. The aim of this retrospective study was to investigate the performance of 68Ga-pentixafor PET/CT for imaging atherosclerosis in comparison to 18F-FDG PET/CT. Methods: Ninety-two patients (37 women and 55 men; mean age, 62 ± 10 y) underwent 68Ga-pentixafor and 18F-FDG PET/CT for staging of oncologic diseases. In these subjects, lesions in the walls of large arteries were identified using morphologic and PET criteria for atherosclerosis (n = 652). Tracer uptake was measured and adjusted for vascular lumen (background) signal by calculation of target-to-background ratios (TBRs) by 2 investigators masked to the other PET scan. On a lesion-to-lesion and patient basis, the TBRs of both PET tracers were compared and additionally correlated to the degree of arterial calcification as quantified in CT. Results: On a lesion-to-lesion basis, 68Ga-pentixafor and 18F-FDG uptake showed a weak correlation (r = 0.28; P < 0.01). 68Ga-pentixafor PET identified more lesions (n = 290; TBR ≥ 1.6, P < 0.01) and demonstrated higher uptake than 18F-FDG PET (1.8 ± 0.5 vs. 1.4 ± 0.4; P < 0.01). The degree of plaque calcification correlated negatively with both 68Ga-pentixafor and 18F-FDG uptake (r = –0.38 vs. –0.31, both P < 0.00001). Conclusion: CXCR4-directed imaging of the arterial wall with 68Ga-pentixafor PET/CT identified more lesions than 18F-FDG PET/CT, with only a weak correlation between tracers. Further studies to elucidate the underlying biologic mechanisms and sources of CXCR4 positivity, and to investigate the clinical utility of chemokine receptor–directed imaging of atherosclerosis, are highly warranted.




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The Transcriptional Aftermath in Two Independently Formed Hybrids of the Opportunistic Pathogen Candida orthopsilosis

ABSTRACT

Interspecific hybridization can drive evolutionary adaptation to novel environments. The Saccharomycotina clade of budding yeasts includes many hybrid lineages, and hybridization has been proposed as a source for new pathogenic species. Candida orthopsilosis is an emerging opportunistic pathogen for which most clinical isolates are hybrids, each derived from one of at least four independent crosses between the same two parental lineages. To gain insight into the transcriptomic aftermath of hybridization in these pathogens, we analyzed allele-specific gene expression in two independently formed hybrid strains and in a homozygous strain representative of one parental lineage. Our results show that the effect of hybridization on overall gene expression is rather limited, affecting ~4% of the genes studied. However, we identified a larger effect in terms of imbalanced allelic expression, affecting ~9.5% of the heterozygous genes in the hybrids. This effect was larger in the hybrid with more extensive loss of heterozygosity, which may indicate a tendency to avoid loss of heterozygosity in these genes. Consistently, the number of shared genes with allele-specific expression in the two independently formed hybrids was higher than random expectation, suggesting selective retention. Some of the imbalanced genes have functions related to pathogenicity, including zinc transport and superoxide dismutase activities. While it remains unclear whether the observed imbalanced genes play a role in virulence, our results suggest that differences in allele-specific expression may add an additional layer of phenotypic plasticity to traits related to virulence in C. orthopsilosis hybrids.

IMPORTANCE How new pathogens emerge is an important question that remains largely unanswered. Some emerging yeast pathogens are hybrids originated through the crossing of two different species, but how hybridization contributes to higher virulence is unclear. Here, we show that hybrids selectively retain gene regulation plasticity inherited from the two parents and that this plasticity affects genes involved in virulence.




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Risk Factors for Diabetic Peripheral Neuropathy and Cardiovascular Autonomic Neuropathy in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study

The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study demonstrated that intensive glucose control reduced the risk of developing diabetic peripheral neuropathy (DPN) and cardiovascular autonomic neuropathy (CAN). We evaluated multiple risk factors and phenotypes associated with DPN and CAN in this large, well-characterized cohort of participants with type 1 diabetes, followed for >23 years. DPN was defined by symptoms, signs, and nerve conduction study abnormalities in ≥2 nerves; CAN was assessed using standardized cardiovascular reflex tests. Generalized estimating equation models assessed the association of DPN and CAN with individual risk factors measured repeatedly. During DCCT/EDIC, 33% of participants developed DPN and 44% CAN. Higher mean HbA1c was the most significant risk factor for DPN, followed by older age, longer duration, greater height, macroalbuminuria, higher mean pulse rate, β-blocker use, and sustained albuminuria. The most significant risk factor for CAN was older age, followed by higher mean HbA1c, sustained albuminuria, longer duration of type 1 diabetes, higher mean pulse rate, higher mean systolic blood pressure, β-blocker use, estimated glomerular filtration rate <60 mL/min/1.73 m2, higher most recent pulse rate, and cigarette smoking. These findings identify risk factors and phenotypes of participants with diabetic neuropathy that can be used in the design of new interventional trials and for personalized approaches to neuropathy prevention.




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Inorganic Nitrate Promotes Glucose Uptake and Oxidative Catabolism in White Adipose Tissue Through the XOR-Catalyzed Nitric Oxide Pathway

An aging global population combined with sedentary lifestyles and unhealthy diets has contributed to an increasing incidence of obesity and type 2 diabetes. These metabolic disorders are associated with perturbations to nitric oxide (NO) signaling and impaired glucose metabolism. Dietary inorganic nitrate, found in high concentration in green leafy vegetables, can be converted to NO in vivo and demonstrates antidiabetic and antiobesity properties in rodents. Alongside tissues including skeletal muscle and liver, white adipose tissue is also an important physiological site of glucose disposal. However, the distinct molecular mechanisms governing the effect of nitrate on adipose tissue glucose metabolism and the contribution of this tissue to the glucose-tolerant phenotype remain to be determined. Using a metabolomic and stable-isotope labeling approach, combined with transcriptional analysis, we found that nitrate increases glucose uptake and oxidative catabolism in primary adipocytes and white adipose tissue of nitrate-treated rats. Mechanistically, we determined that nitrate induces these phenotypic changes in primary adipocytes through the xanthine oxidoreductase–catalyzed reduction of nitrate to NO and independently of peroxisome proliferator–activated receptor-α. The nitrate-mediated enhancement of glucose uptake and catabolism in white adipose tissue may be a key contributor to the antidiabetic effects of this anion.




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Loss of cerebellar function selectively affects intrinsic rhythmicity of eupneic breathing [RESEARCH ARTICLE]

Yu Liu, Shuhua Qi, Fridtjof Thomas, Brittany L. Correia, Angela P. Taylor, Roy V. Sillitoe, and Detlef H. Heck

Respiration is controlled by central pattern generating circuits in the brain stem, whose activity can be modulated by inputs from other brain areas to adapt respiration to autonomic and behavioral demands. The cerebellum is known to be part of the neuronal circuitry activated during respiratory challenges, such as hunger for air, but has not been found to be involved in the control of spontaneous, unobstructed breathing (eupnea). Here we applied a measure of intrinsic rhythmicity, the CV2, which evaluates the similarity of subsequent intervals and is thus sensitive to changes in rhythmicity at the temporal resolution of individual respiratory intervals. The variability of intrinsic respiratory rhythmicity was reduced in a mouse model of cerebellar ataxia compared to their healthy littermates. Irrespective of that difference, the average respiratory rate and the average coefficient of variation (CV) were comparable between healthy and ataxic mice. We argue that these findings are consistent with a proposed role of the cerebellum in modulating the duration of individual respiratory intervals, which could serve the purpose of coordinating respiration with other rhythmic orofacial movements, such as fluid licking and swallowing.




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Nucleolar stress in Drosophila neuroblasts, a model for human ribosomopathies [RESEARCH ARTICLE]

Sonu Shrestha Baral, Molly E. Lieux, and Patrick J. DiMario

Different stem cells or progenitor cells display variable threshold requirements for functional ribosomes. This is particularly true for several human ribosomopathies in which select embryonic neural crest cells or adult bone marrow stem cells, but not others, show lethality due to failures in ribosome biogenesis or function (now known as nucleolar stress). To determine if various Drosophila neuroblasts display differential sensitivities to nucleolar stress, we used CRISPR-Cas9 to disrupt the Nopp140 gene that encodes two splice variant ribosome biogenesis factors (RBFs). Disruption of Nopp140 induced nucleolar stress that arrested larvae in the second instar stage. While the majority of larval neuroblasts arrested development, the mushroom body (MB) neuroblasts continued to proliferate as shown by their maintenance of deadpan, a neuroblast-specific transcription factor, and by their continued EdU incorporation. MB neuroblasts in wild-type larvae appeared to contain more fibrillarin and Nopp140 in their nucleoli as compared to other neuroblasts, indicating that MB neuroblasts stockpile RBFs as they proliferate in late embryogenesis while other neuroblasts normally enter quiescence. A greater abundance of Nopp140 encoded by maternal transcripts in Nopp140-/- MB neuroblasts of 1­­­–2-day-old larvae likely rendered these cells more resilient to nucleolar stress.

This article has an associated First Person interview with the first author of the paper.




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Association of Serum Uromodulin with Death, Cardiovascular Events, and Kidney Failure in CKD

Background and objectives

Uromodulin is exclusively produced by tubular epithelial cells and released into urine and serum. Higher serum uromodulin has been associated with lower risk for kidney failure in Chinese patients with CKD and with lower risk for mortality in the elderly and in patients undergoing coronary angiography. We hypothesized that lower serum uromodulin is associated with mortality, cardiovascular events, and kidney failure in white patients with CKD.

Design, setting, participants, & measurements

We measured serum uromodulin in 5143 participants enrolled in the German CKD (GCKD) study. The associations of baseline serum uromodulin with all-cause mortality, major adverse cardiovascular events (MACE; a composite of cardiovascular mortality, nonfatal myocardial infarction or stroke, or incident peripheral vascular disease), and kidney failure (dialysis or transplantation) were evaluated using multivariable Cox proportional hazard regression analyses in a cohort study design, adjusting for demographics, eGFR, albuminuria, cardiovascular risk factors, and medication.

Results

The mean age of participants was 60±12 years, 60% were male. Mean serum uromodulin concentration was 98±60 ng/ml, eGFR was 49±18 ml/min per 1.73 m2, and 78% had eGFR <60 ml/min per 1.73 m2. Participants in lower serum uromodulin quartiles had lower eGFR and higher albuminuria, prevalence of diabetes, hypertension, coronary artery disease, and more frequent history of stroke at baseline. During a follow-up of 4 years, 335 participants died, 417 developed MACE, and 229 developed kidney failure. In multivariable analysis, the highest serum uromodulin quartile was associated with lower hazard for mortality (hazard ratio [HR], 0.57; 95% CI, 0.38 to 0.87), MACE (HR, 0.63; 95% CI, 0.45 to 0.90), and kidney failure (HR, 0.24; 95% CI, 0.10 to 0.55) compared with the lowest quartile.

Conclusions

Higher serum uromodulin is independently associated with lower risk for mortality, cardiovascular events, and kidney failure in white patients with CKD.

Clinical Trial registry name and registration number

Deutsches Register für Klinische Studien (DRKS; German national database of clinical studies), DRKS00003971.




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Associations of Cardiac, Kidney, and Diabetes Biomarkers With Peripheral Neuropathy among Older Adults in the Atherosclerosis Risk in Communities (ARIC) Study

Abstract
Background
The aim of this study was to assess the association of high-sensitivity cardiac troponin (hs-cTnT) and other cardiac, kidney, hyperglycemia, and inflammatory biomarkers with peripheral neuropathy (PN) in a community-based population.
Methods
We conducted a cross-sectional analysis of 3056 black and white participants in the Atherosclerosis Risk in Communities (ARIC) study who underwent standardized monofilament PN testing and had measures of cardiac function (hs-cTnT, N-terminal pro–B-type natriuretic peptide [NT-proBNP], and growth differentiation factor 15 [GDF15]), kidney function (serum creatinine, cystatin C, β-2 microglobulin, urine albumin-to-creatinine ratio), hyperglycemia (fasting glucose, hemoglobin A1c [Hb A1c], fructosamine, glycated albumin, 1,5-anhydroglucitol), and inflammation (C-reactive protein) assessed at visit 6 (2016–2017; age 71–94 years). We used logistic regression to assess the associations of these biomarkers (modeled in diabetes-specific tertiles) with PN in older adults with and without diabetes after adjusting for traditional risk factors.
Results
In total, 33.5% of participants had PN (37.3% with diabetes and 31.9% without diabetes). There was an independent association of hs-cTnT with PN regardless of diabetes status (diabetes T3 vs. T1: odds ratio [OR], 2.15 [95% CI, 1.44–3.22]; no diabetes: OR, 2.31 [95%CI, 1.76–3.03]; P = 0.72 for interaction). Among participants without diabetes, there were also significant associations of NT-proBNP (OR, 1.40 [95% CI, 1.08–1.81]) and urine albumin-to-creatinine ratio (OR, 1.55 [95% CI, 1.22–1.97]) with PN. Associations of hyperglycemia biomarkers including Hb A1c (OR, 1.76 [95% CI, 1.22–2.54]), fructosamine (OR, 1.71 [95% CI, 1.19–2.46]), and glycated albumin (OR, 1.45 [95% CI, 1.03–2.03]) with PN were significant only among participants with diabetes.
Conclusions
Overall, hs-cTnT appears to be a global marker of end organ damage, including PN. Laboratory biomarkers may be able to help us identify those individuals with PN.




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Peripheral Neuropathy—Time for Better Biomarkers?

Peripheral neuropathy (PN) is a condition affecting up to 20% of the general population. The symptoms range from mild to disabling, depending on the types of nerve fiber affected and the type and severity of damage.




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Systems Analysis Implicates WAVE2 Complex in the Pathogenesis of Developmental Left-Sided Obstructive Heart Defects

Genetic variants are the primary driver of congenital heart disease (CHD) pathogenesis. However, our ability to identify causative variants is limited. To identify causal CHD genes that are associated with specific molecular functions, the study used prior knowledge to filter de novo variants from 2,881 probands with sporadic severe CHD. This approach enabled the authors to identify an association between left ventricular outflow tract obstruction lesions and genes associated with the WAVE2 complex and regulation of small GTPase-mediated signal transduction. Using CRISPR zebrafish knockdowns, the study confirmed that WAVE2 complex proteins brk1, nckap1, and wasf2 and the regulators of small GTPase signaling cul3a and racgap1 are critical to cardiac development.




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Targeting Phosphorylcholine in Established Atherosclerosis?




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Therapeutic Antibody Against Phosphorylcholine Preserves Coronary Function and Attenuates Vascular 18F-FDG Uptake in Atherosclerotic Mice

This study showed that treatment with a therapeutic monoclonal immunoglobulin-G1 antibody against phosphorylcholine on oxidized phospholipids preserves coronary flow reserve and attenuates atherosclerotic inflammation as determined by the uptake of 18F-fluorodeoxyglucose in atherosclerotic mice. The noninvasive imaging techniques represent translational tools to assess the efficacy of phosphorylcholine-targeted therapy on coronary artery function and atherosclerosis in clinical studies.




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Continuous professional development: elevating sleep and breathing disorder education in Europe

Sleep and breathing disorders are highly prevalent, representing a growing subspecialty of respiratory medicine. The term sleep disordered breathing (SDB) encompasses a range of conditions characterised by abnormal breathing during sleep, from chronic or habitual snoring, to frank obstructive sleep apnoea (OSA) or, in some cases, central sleep apnoea (CSA) and hypoventilation syndromes. OSA is the commonest form of SDB, leading to many potential consequences and adverse clinical outcomes, including excessive daytime sleepiness, impaired daytime function, metabolic dysfunction, and an increased risk of cardiovascular disease and mortality [1]. The estimated reported prevalence of moderate-to-severe SDB (≥15 events·h–1) was 23.4% in women and 49.7% in men, and the prevalence of symptomatic OSA was 9% and 13%, respectively [2]. However, in some populations, the prevalence of OSA is substantially higher, such as in patients been evaluated for bariatric surgery (estimated range 70–80%), in patients who have had a transient ischaemic attack or stroke (estimated range 60–70%) and in patients with cardiometabolic disease [3–6]. Limited data have been reported on CSA and non-obstructive sleep-related hypoventilation, which have received considerable interest in the sleep field within the past 10 years. Even if their prevalence was noted to be quite low relative to the prevalence of OSA [7], they are quite common in specific subpopulations [8–10].




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Clinical implications of ANCA positivity in idiopathic pulmonary fibrosis patients

The diagnostic process of idiopathic interstitial pneumonias (IIPs) is complex and the underlying mechanisms that participate in these diseases still need to be fully understood. In 2015, the European Respiratory Society/American Thoracic Society Task Force on Undifferentiated Forms of Connective Tissue Disease-Associated Interstitial Lung Disease introduced the term "interstitial pneumonia with autoimmune features" (IPAF) to identify subjects with IIP and features suggesting background autoimmunity but not characterisable connective tissue disease (CTD) [1]. The need for a proper clinical, serological and morphological assessment of IIP was highlighted to identify potential subjects with IPAF and CTD-ILD. However, the measurement of anti-neutrophil cytoplasmic antibodies (ANCAs) is not included in the definition of IPAF and ANCA serological testing is only recommended in idiopathic pulmonary fibrosis (IPF) when a clinical suspicion of vasculitis exists [2]. As current research evaluates the prognostic relevance of autoimmune features in IIP, the clinical importance of ANCA positivity still needs to be determined.




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Breathe




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Adverse Events With Central Venous Catheters




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Intrathecal Antibacterial and Antifungal Therapies [Reviews]

Intrathecal administration of anti-infectives is indicated in central nervous system infections by multiresistant pathogens when drugs that can reach adequate cerebrospinal fluid (CSF) concentrations by systemic therapy are not available. Antibiotics that readily pass the blood-brain and blood-CSF barriers and/or that have low toxicity allowing an increase in the daily dosage should not be used for intrathecal therapy. Intrathecal therapy is accompanied by systemic treatment. Antibacterials indispensable for intrathecal therapy include aminoglycosides, colistin, daptomycin, tigecycline, and vancomycin. Limited experience suggests the utility of the antifungals amphotericin B and caspofungin. Intraventricular administration ensures distribution throughout the CSF compartment, whereas intralumbar dosing often fails to attain adequate antibiotic concentrations in the ventricles. The individual dose is determined by the estimated size of the CSF space and by the estimated clearance from CSF. For moderately lipophilic anti-infectives with a molecular weight above approximately 1,000 g/mol, as well as for hydrophilic drugs with a molecular weight above approximately 400 g/mol, one daily dose is normally adequate. The ventricular drain should be clamped for 15 to 120 min to facilitate the distribution of the anti-infective in the CSF space. Therapeutic drug monitoring of the trough levels is necessary only in cases of therapeutic failure.




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Thiostrepton Reactivates Latent HIV-1 through the p-TEFb and NF-{kappa}B Pathways Mediated by Heat Shock Response [Antiviral Agents]

Antiretroviral therapy (ART) suppresses HIV-1 replication but fails to cure the infection. The presence of an extremely stable viral latent reservoir, primarily in resting memory CD4+ T cells, remains a major obstacle to viral eradication. The "shock and kill" strategy targets these latently infected cells and boosts immune recognition and clearance, and thus, it is a promising approach for an HIV-1 functional cure. Although some latency-reversing agents (LRAs) have been reported, no apparent clinical progress has been made, so it is still vital to seek novel and effective LRAs. Here, we report that thiostrepton (TSR), a proteasome inhibitor, reactivates latent HIV-1 effectively in cellular models and in primary CD4+ T cells from ART-suppressed individuals ex vivo. TSR does not induce global T cell activation, severe cytotoxicity, or CD8+ T cell dysfunction, making it a prospective LRA candidate. We also observed a significant synergistic effect of reactivation when TSR was combined with JQ1, prostratin, or bryostatin-1. Interestingly, six TSR analogues also show reactivation abilities that are similar to or more effective than that of TSR. We further verified that TSR upregulated expression of heat shock proteins (HSPs) in CD4+ T cells, which subsequently activated positive transcriptional elongation factor b (p-TEFb) and NF-B signals, leading to viral reactivation. In summary, we identify TSR as a novel LRA which could have important significance for applications to an HIV-1 functional cure in the future.