1 Problem Notes for SAS®9 - 65898: A misleading SASTRACE message appears in the log when you insert a row into an Oracle table using SAS/ACCESS Interface to Oracle with DBIDIRECTEXEC By feedproxy.google.com Published On :: Thu, 30 Apr 2020 13:52:24 EST When you add one row to an Oracle table using DBIDIRECTEXEC, you see the following misleading trace message: "ORACLE: 4294967296 rows inserted/updated/deleted." You should see something similar to the following: "ORACLE: 1 rows inserte Full Article ORACLE+SAS/ACCESS+Interface+to+Oracle
1 Problem Notes for SAS®9 - 65909: SAS Visual Analytics Designer 7.5 responds slowly when you edit large or complex reports By feedproxy.google.com Published On :: Thu, 30 Apr 2020 13:26:35 EST If your SAS Visual Analytics report contains many sections and objects, you might encounter performance problems when you are editing the report. A hot fix is planned for this issue. Full Article VISANLYTBNDL+SAS+Visual+Analytics
1 Problem Notes for SAS®9 - 64980: The PRINT procedure contains a buffer-overrun vulnerability By feedproxy.google.com Published On :: Thu, 30 Apr 2020 10:19:20 EST Severity: Medium Description: PROC PRINT might fail with a buffer overrun when you submit it in conjunction with certain malformed SAS statements. Full Article BASE+Base+SAS
1 Problem Notes for SAS®9 - 64550: SAS Enterprise Case Management contains a cross-site scripting vulnerability in the CASE_ID parameter By feedproxy.google.com Published On :: Thu, 30 Apr 2020 10:18:27 EST Severity: Medium Description: SAS Enterprise Case Management contains a cross-site scripting vulnerability in the CASE_ID parameter. Potential Impact: Full Article CASEMGMTOFR+SAS+Enterprise+Case+Manageme
1 Problem Notes for SAS®9 - 65893: Custom sorts are sorted incorrectly when they are used in a hierarchy in SAS Visual Analytics Designer By feedproxy.google.com Published On :: Wed, 29 Apr 2020 12:29:05 EST A custom sort might be sorted incorrectly when the data item is used in a custom category, which is then used in a hierarchy. The issue can occur in the following scenario: Full Article VISANLYTBNDL+SAS+Visual+Analytics
1 Problem Notes for SAS®9 - 65844: STRESS task fails with "Fatal error in PMPI_Bcast: Other MPI error, error stack: PMPI_Bcast(1478)" By feedproxy.google.com Published On :: Tue, 28 Apr 2020 13:35:57 EST In SAS High-Performance Risk, a STRESS task might fail with a message like the following in the SAS log while the compute server is sending the ScenarioCF/Value data to the HPRisk Engine: Full Article HPRISKOFR+SAS+High-Performance+Risk
1 Problem Notes for SAS®9 - 65835: A series of PROC SQL queries might not generate a distinct set of rows By feedproxy.google.com Published On :: Tue, 28 Apr 2020 12:39:06 EST A set of PROC SQL queries that create a view, contain a constant column, contain a computed column, and a create a table do not generate a unique set of rows in the table that is created. Full Article BASE+Base+SAS
1 Problem Notes for SAS®9 - 65597: An SQL procedure query with a WHERE clause that contains multiple subselects might return incorrect results By feedproxy.google.com Published On :: Tue, 28 Apr 2020 12:37:41 EST An issue occurs when code contains a complex SQL procedure query with a WHERE clause that contains multiple subselects. Incorrect results might be returned. Click the Hot Fix tab in this note to Full Article BASE+Base+SAS
1 Problem Notes for SAS®9 - 65572: The length of a string variable might be longer than specified with the MAX_CHAR_LEN= option By feedproxy.google.com Published On :: Tue, 28 Apr 2020 08:30:03 EST When you read in a BigQuery table, the length of string variables might be longer than the length specified with the MAX_CHAR_LEN= option when running your SAS software with UTF-8. By Full Article BIGQUERY+SAS/ACCESS+Interface+to+Google+
1 Problem Notes for SAS®9 - 65883: SAS Workflow Studio returns a "cannot load" error when you try to open the CECL_Cycle_AFS workflow template for SAS Solution for CECL By feedproxy.google.com Published On :: Mon, 27 Apr 2020 16:10:54 EST You might see the following error in SAS Workflow Studio when you try to open the CECL_Cycle_AFS workflow template that is shipped with SAS Solution for CECL: Full Article RGPBNDL+SAS+Risk+Governance+Framework
1 Problem Notes for SAS®9 - 65856: The process of updating a lookup table in SAS Business Rules Manager (running in UNIX operating environments) does not work properly By feedproxy.google.com Published On :: Mon, 27 Apr 2020 13:37:52 EST Under UNIX, the process of updating a lookup table in SAS Business Rules Manager does not work properly. The problem occurs when you perform these steps: Open a lookup table. Cl Full Article BRLSTBNDL+SAS+Business+Rules+Manager
1 Problem Notes for SAS®9 - 65869: SAS Visual Data Builder does not enable you to schedule with multiple time-event triggers By feedproxy.google.com Published On :: Fri, 24 Apr 2020 12:23:04 EST SAS Visual Data Builder might not enable you to create multiple time-event triggers. The + button to add another trigger is not available to select, as shown in the following display: imgalt="" src="{fusion_658 Full Article VISANLYTBNDL+SAS+Visual+Analytics
1 Problem Notes for SAS®9 - 65868: Saving a report distribution in SAS Visual Analytics Designer fails with "The name is invalid" By feedproxy.google.com Published On :: Fri, 24 Apr 2020 12:03:57 EST When you attempt to save a report distribution in SAS Visual Analytics Designer, you might see the error shown in the following display: imgalt="" src="{fusion_65868_1_distributionerror.png}" /> Full Article VISANLYTBNDL+SAS+Visual+Analytics
1 Rays' 2019 mantra: Prepare to win from within By mlb.mlb.com Published On :: Fri, 8 Feb 2019 16:05:02 EDT Over the past couple seasons, the Rays have preached patience as the organization provided time for the top prospects to make it up to the Majors. Now, the focus has been primarily in remaining flexible and keeping positions open for the young talent arriving from the Minors. Full Article
1 Bulked-up Duffy looks to sustain at plate in '19 By mlb.mlb.com Published On :: Sat, 9 Feb 2019 17:43:24 EDT As Matt Duffy entered the offseason, he knew that he needed to add strength in order to hold up over the course of a 162-game season. The 28-year old has been at the Rays' Spring Training facility in Port Charlotte, Fla., for about a week, and he believes his improved shape will help the team fight for a playoff spot in 2019. Full Article
1 Uniform patch to mark 150 years of pro baseball By mlb.mlb.com Published On :: Tue, 12 Feb 2019 10:09:05 EDT All 30 Major League teams will wear special "MLB 150" patches on their uniforms for the entire 2019 season in honor of the 150th anniversary of the 1869 Cincinnati Red Stockings, the first openly all-salaried professional baseball team. Full Article
1 Rays two-way prospect McKay to DH only in '19 By mlb.mlb.com Published On :: Mon, 11 Feb 2019 11:45:51 EDT Brendan McKay is still going to be a two-way player, but the Rays are planning to narrow his focus on the hitting side by keeping him to designated hitter-only duties, a source confirmed to MLB.com's Juan Toribio on Monday. Full Article
1 Snell not feeling pressure in '19 after Cy win By mlb.mlb.com Published On :: Wed, 13 Feb 2019 11:52:53 EDT After winning the 2018 American League Cy Young Award, Blake Snell said he doesn't feel "any pressure" in '19. Full Article
1 Kiermaier eyeing 'huge rebound year' in 2019 By mlb.mlb.com Published On :: Sat, 16 Feb 2019 11:43:28 EDT Kevin Kiermaier has always played with a chip on his shoulder, but he admits that there's some extra motivation heading into Spring Training after a frustrating 2018 season. Full Article
1 Here are 10 Rays players to watch this spring By mlb.mlb.com Published On :: Sun, 17 Feb 2019 13:46:36 EDT While most of the attention will fall on the players who are expected to make the Opening Day roster, manager Kevin Cash and the rest of the organization will be keeping a close eye on some of the players that could find their way to the big leagues at some point within the next year. Full Article
1 Sternberg optimistic about 2019, Rays' stadium By mlb.mlb.com Published On :: Tue, 19 Feb 2019 17:49:38 EDT Rays principal owner Stuart Sternberg won't make any big prediction entering the 2019 season, but he still expressed a lot of enthusiasm during Tuesday's media session. Full Article
1 ADAM10 and ADAM17 proteases mediate proinflammatory cytokine-induced and constitutive cleavage of endomucin from the endothelial surface [Membrane Biology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Contact between inflammatory cells and endothelial cells (ECs) is a crucial step in vascular inflammation. Recently, we demonstrated that the cell-surface level of endomucin (EMCN), a heavily O-glycosylated single-transmembrane sialomucin, interferes with the interactions between inflammatory cells and ECs. We have also shown that, in response to an inflammatory stimulus, EMCN is cleared from the cell surface by an unknown mechanism. In this study, using adenovirus-mediated overexpression of a tagged EMCN in human umbilical vein ECs, we found that treatment with tumor necrosis factor α (TNF-α) or the strong oxidant pervanadate leads to loss of cell-surface EMCN and increases the levels of the C-terminal fragment of EMCN 3- to 4-fold. Furthermore, treatment with the broad-spectrum matrix metalloproteinase inhibitor batimastat (BB94) or inhibition of ADAM metallopeptidase domain 10 (ADAM10) and ADAM17 with two small-molecule inhibitors, GW280264X and GI254023X, or with siRNA significantly reduced basal and TNFα-induced cell-surface EMCN cleavage. Release of the C-terminal fragment of EMCN by TNF-α treatment was blocked by chemical inhibition of ADAM10 alone or in combination with ADAM17. These results indicate that cell-surface EMCN undergoes constitutive cleavage and that TNF-α treatment dramatically increases this cleavage, which is mediated predominantly by ADAM10 and ADAM17. As endothelial cell-surface EMCN attenuates leukocyte–EC interactions during inflammation, we propose that EMCN is a potential therapeutic target to manage vascular inflammation. Full Article
1 Adipose Triglyceride Lipase is a Key Lipase for the Mobilization of Lipid Droplets in Human Beta Cells and Critical for the Maintenance of Syntaxin1a Level in Beta Cells By diabetes.diabetesjournals.org Published On :: 2020-03-31T14:12:19-07:00 Lipid droplets (LDs) are frequently increased when excessive lipid accumulation leads to cellular dysfunction. Distinct from mouse beta cells, LDs are prominent in human beta cells, however, the regulation of LD mobilization (lipolysis) in human beta cells remains unclear. We found that glucose increases lipolysis in non-diabetic human islets, but not in type 2 diabetic (T2D) islets, indicating dysregulation of lipolysis in T2D islets. Silencing adipose triglyceride lipase (ATGL) in human pseudoislets (shATGL) increased triglycerides, and the number and size of LDs indicating that ATGL is the principal lipase in human beta cells. In shATGL pseudoislets, biphasic glucose-stimulated insulin secretion (GSIS) and insulin secretion to IBMX and KCl were all reduced without altering oxygen consumption rate compared with scramble control. Like human islets, INS1 cells showed visible LDs, glucose responsive lipolysis, and impairment of GSIS after ATGL silencing. ATGL deficient INS1 cells and human pseudoislets showed reduced Stx1a, a key SNARE component. Proteasomal degradation of Stx1a was accelerated likely through reduced palmitoylation in ATGL deficient INS1 cells. Therefore, ATGL is responsible for LD mobilization in human beta cells and supports insulin secretion by stabilizing Stx1a. The dysregulated lipolysis may contribute to LD accumulation and beta cell dysfunction in T2D islets. Full Article
1 Adipose Triglyceride Lipase is a Key Lipase for the Mobilization of Lipid Droplets in Human Beta Cells and Critical for the Maintenance of Syntaxin1a Level in Beta Cells By diabetes.diabetesjournals.org Published On :: 2020-04-20T08:51:08-07:00 Lipid droplets (LDs) are frequently increased when excessive lipid accumulation leads to cellular dysfunction. Distinct from mouse beta cells, LDs are prominent in human beta cells, however, the regulation of LD mobilization (lipolysis) in human beta cells remains unclear. We found that glucose increases lipolysis in non-diabetic human islets, but not in type 2 diabetic (T2D) islets, indicating dysregulation of lipolysis in T2D islets. Silencing adipose triglyceride lipase (ATGL) in human pseudoislets (shATGL) increased triglycerides, and the number and size of LDs indicating that ATGL is the principal lipase in human beta cells. In shATGL pseudoislets, biphasic glucose-stimulated insulin secretion (GSIS) and insulin secretion to IBMX and KCl were all reduced without altering oxygen consumption rate compared with scramble control. Like human islets, INS1 cells showed visible LDs, glucose responsive lipolysis, and impairment of GSIS after ATGL silencing. ATGL deficient INS1 cells and human pseudoislets showed reduced Stx1a, a key SNARE component. Proteasomal degradation of Stx1a was accelerated likely through reduced palmitoylation in ATGL deficient INS1 cells. Therefore, ATGL is responsible for LD mobilization in human beta cells and supports insulin secretion by stabilizing Stx1a. The dysregulated lipolysis may contribute to LD accumulation and beta cell dysfunction in T2D islets. Full Article
1 Dopamine and Early Retinal Dysfunction in Diabetes: Insights From a Phase 1 Study By diabetes.diabetesjournals.org Published On :: 2020-04-20T15:26:16-07:00 Full Article
1 Revisiting Proinsulin Processing: Evidence That Human {beta}-Cells Process Proinsulin With Prohormone Convertase (PC) 1/3 But Not PC2 By diabetes.diabetesjournals.org Published On :: 2020-04-24T11:09:35-07:00 Insulin is first produced in pancreatic β-cells as the precursor prohormone proinsulin. Defective proinsulin processing has been implicated in the pathogenesis of both type 1 and type 2 diabetes. Though there is substantial evidence that mouse β-cells process proinsulin using prohormone convertase 1/3 (PC1/3) then prohormone convertase 2 (PC2), this finding has not been verified in human β-cells. Immunofluorescence with validated antibodies reveals that there was no detectable PC2 immunoreactivity in human β-cells and little PCSK2 mRNA by in situ hybridization. Similarly, rat β-cells were not immunoreactive for PC2. In all histological experiments, PC2 immunoreactivity in neighbouring α-cells acts as a positive control. In donors with type 2 diabetes, β-cells had elevated PC2 immunoreactivity, suggesting that aberrant PC2 expression may contribute to impaired proinsulin processing in β-cells of patients with diabetes. To support histological findings using a biochemical approach, human islets were used for pulse-chase experiments. Despite inhibition of PC2 function by temperature blockade, brefeldin-A, chloroquine, and multiple inhibitors that blocked production of mature glucagon from proglucagon, β-cells retained the ability to produce mature insulin. Conversely, suppression of PC1/3 blocked processing of proinsulin but not proglucagon. By demonstrating that healthy human β-cells process proinsulin by PC1/3 but not PC2 we suggest that there is a need to revise the longstanding theory of proinsulin processing. Full Article
1 Hybrid Insulin Peptides are Recognized by Human T Cells in the Context of DRB1*04:01 By diabetes.diabetesjournals.org Published On :: 2020-04-24T13:05:31-07:00 T cells isolated from the pancreatic infiltrates of non-obese diabetic mice have been shown to recognize epitopes formed by the covalent cross-linking of proinsulin and secretory granule peptides. Formation of such hybrid insulin peptides (HIPs) was confirmed through mass spectrometry and responses to HIPs were observed among the islet-infiltrating T cells of pancreatic organ donors and in the peripheral blood of individuals with type 1 diabetes (T1D). However, questions remain about the prevalence of HIP-specific T cells in humans, the sequences they recognize, and their role in disease. We identified six novel HIPs that are recognized in the context of DRB1*04:01, discovered by utilizing a library of theoretical HIP sequences derived from insulin fragments covalently linked to one another or to fragments of secretory granule proteins or other islet-derived proteins. We demonstrate that T cells that recognize these HIPs are detectable in the peripheral blood of subjects with T1D and exhibit an effector memory phenotype. HIP-reactive T cell clones produced Th1-associated cytokines and proliferated in response to human islet preparations. These results support the relevance of HIPs in human disease, further establishing a novel post-translational modification that may contribute to the loss of peripheral tolerance in T1D. Full Article
1 Acute Hyperglycemia Increases Brain Pregenual Anterior Cingulate Cortex Glutamate Concentrations in Type 1 Diabetes Mellitus By diabetes.diabetesjournals.org Published On :: 2020-04-24T14:58:49-07:00 The brain mechanisms underlying the association of hyperglycemia with depressive symptoms are unknown. We hypothesized that disrupted glutamate metabolism in pregenual anterior cingulate cortex (ACC) in type 1 diabetes (T1D) without depression affects emotional processing. Using proton magnetic resonance spectroscopy (MRS), we measured glutamate concentrations in ACC and occipital cortex (OCC) in 13 T1D without major depression (HbA1c=7.1±0.7% [54±7mmol/mol]) and 11 healthy non-diabetic controls (HbA1c=5.5±0.2% [37±3mmol/mol]) during fasting euglycemia (EU) followed by a 60-minute +5.5mmol/l hyperglycemic clamp (HG). Intrinsic neuronal activity was assessed using resting-state blood oxygen level dependent functional MRI to measure the fractional amplitude of low frequency fluctuations in slow-band 4 (fALFF4). Emotional processing and depressive symptoms were assessed using emotional tasks (Emotional-Stroop, Self-Referent-Encoding-Task SRET) and clinical ratings (HAM-D, SCL-90-R), respectively. During HG, ACC glutamate increased (1.2mmol/kg, +10%, p=0.014) while ACC fALFF4 was unchanged (-0.007, -2%, p=0.449) in T1D; in contrast, glutamate was unchanged (-0.2mmol/kg, -2%, p=0.578) while fALFF4 decreased (-0.05, -13%, p=0.002) in controls. OCC glutamate and fALFF4 were unchanged in both groups. T1D had longer SRET negative-word response-times (p=0.017) and higher depression-rating scores (HAM-D p=0.020; SCL-90-R-depression p=0.008). Higher glutamate change tended to associate with longer Emotional-Stroop response-times in T1D only. Brain glutamate must be tightly controlled during hyperglycemia due to the risk for neurotoxicity with excessive levels. Results suggest that ACC glutamate control mechanisms are disrupted in T1D, which affects glutamatergic neurotransmission related to emotional or cognitive processing. Increased prefrontal glutamate during acute hyperglycemic episodes could explain our previous findings of associations between chronic hyperglycemia, cortical thinning and depressive symptoms in T1D. Full Article
1 TWIST1-Reprogrammed Endothelial Cell Transplantation Potentiates Neovascularization-Mediated Diabetic Wound Tissue Regeneration By diabetes.diabetesjournals.org Published On :: 2020-04-24T20:01:59-07:00 Hypo-vascularised diabetic non-healing wounds are due to reduced number and impaired physiology of endogenous endothelial progenitor cell (EPC) population that, limits their recruitment and mobilization at the wound site. To enrich the EPC repertoire from non-endothelial precursors, abundantly available mesenchymal stromal cells (MSCs) were reprogrammed into induced-endothelial cells (iECs). We identified cell signaling molecular targets by meta-analysis of microarray datasets. BMP-2 induction leads to the expression of inhibitory Smad 6/7-dependent negative transcriptional regulation of ID1, rendering the latter's reduced binding to TWIST1 during transdifferentiation of WJ-MSC into iEC. TWIST1, in turn, regulates endothelial genes transcription, positively of pro-angiogenic-KDR and negatively, in part, of anti-angiogenic-SFRP4. Twist1 reprogramming enhanced the endothelial lineage commitment of WJ-MSC, increased the vasculogenic potential of reprogrammed EC (rEC). Transplantation of stable TWIST1-rECs into full-thickness type 1 and 2 diabetic-splinted wound healing murine model enhanced the microcirculatory blood flow and accelerated the wound tissue regeneration. An increased or decreased co-localization of GFP with KDR/SFRP4 and CD31 in the regenerated diabetic wound bed with TWIST1 overexpression or silencing (piLenti-TWIST1-shRNA-GFP), respectively further confirmed improved neovascularization. This study depicted the reprogramming of WJ-MSCs into rECs using unique transcription factors, TWIST1 for an efficacious cell transplantation therapy to induce neovascularization–mediated diabetic wound tissue regeneration. Full Article
1 Motifs of Three HLA-DQ Amino Acid Residues ({alpha}44, {beta}57, {beta}135) Capture Full Association with the Risk of Type 1 Diabetes in DQ2 and DQ8 Children By diabetes.diabetesjournals.org Published On :: 2020-04-24T20:01:59-07:00 HLA-DQA1 and -DQB1 are strongly associated with type 1 diabetes (T1D), and DQ8.1 and DQ2.5 are major risk haplotypes. Next generation targeted sequencing of HLA-DQA1 and -DQB1 in Swedish newly diagnosed 1-18 year-old patients (n=962) and controls (n=636) was used to construct abbreviated DQ haplotypes, converted into amino acid (AA) residues, and assessed for their associations with T1D. A hierarchically-organized haplotype (HOH) association analysis, allowed 45 unique DQ haplotypes to be categorized into seven clusters. The DQ8/9 cluster included two DQ8.1 risk and the DQ9 resistant haplotypes, and the DQ2 cluster, included the DQ2.5 risk and DQ2.2 resistant haplotypes. Within each cluster, HOH found residues α44Q (OR 3.29, p=2.38*10-85 ) and β57A (OR 3.44, p=3.80*10-84) to be associated with T1D in the DQ8/9 cluster representing all ten residues (α22, α23, α44, α49, α51, α53, α54, α73, α184, β57) due to complete linkage-disequilibrium (LD) of α44 with eight such residues. Within the DQ2 cluster and due to LD, HOH analysis found α44C and β135D to share the risk for T1D (OR 2.10, p=1.96*10-20). The motif "QAD" of α44, β57, and β135 captured the T1D risk association of DQ8.1 (OR 3.44, p=3.80*10-84), the corresponding motif "CAD" captured the risk association of DQ2.5 (OR 2.10, p=1.96*10-20). Two risk associations were related to GADA and IA-2A, but in opposite directions. "CAD" was positively associated with GADA (OR 1.56; p=6.35*10-8) but negatively with IA-2A (OR 0.59, p= 6.55*10-11). "QAD" was negatively associated with GADA (OR 0.88; p= 3.70*10-3) but positively with IA-2A (OR 1.64; p= 2.40*10-14), despite a single difference at α44. The residues are found in and around anchor pockets 1 and 9, as potential TCR contacts, in the areas for CD4 binding and putative homodimer formation. The identification of three HLA-DQ AA (α44, β57, β135) conferring T1D risk should sharpen functional and translational studies. Full Article
1 The Metabolic Responses to 24-h Fasting and Mild Cold Exposure in Overweight Individuals are Correlated and Accompanied by Changes in FGF21 Concentration By diabetes.diabetesjournals.org Published On :: 2020-04-27T16:35:54-07:00 A greater decrease in 24-h energy expenditure (24EE) during 24h fasting defines a thriftier metabolic phenotype prone to weight gain during overfeeding and resistant to weight loss during caloric restriction. As the thermogenic response to mild cold exposure (COLD) may similarly characterize this human phenotype identified by acute fasting conditions, we analyzed changes in 24EE and sleeping metabolic rate (SLEEP) in a whole-room indirect calorimeter during 24h fasting at thermoneutrality (24°C) and during energy balance both at thermoneutrality (24°C) and mild cold (19°C) in 20 healthy volunteers (80% male, age: 36.6±11.4y, percentage body fat: 34.8±10.5%). Greater decrease in 24EE during fasting (thriftier phenotype) was associated with less increase in 24EE during COLD, i.e. less cold-induced thermogenesis. Greater decreases in plasma fibroblast growth factor 21 (FGF21) after 24h fasting and after COLD were highly correlated and associated with greater decreases in SLEEP in both conditions. We conclude that the metabolic responses to short-term fasting and COLD are associated and mediated by the liver-derived hormone FGF21. Thus, the 24EE response to COLD further identifies the thrifty versus spendthrift phenotype, providing an additional setting to investigate the physiological mechanisms underlying the human metabolic phenotype and characterizing the individual susceptibility to weight change. Full Article
1 Necrostatin-1 Mitigates Cognitive Dysfunction in Prediabetic Rats With no Alteration in Insulin Sensitivity By diabetes.diabetesjournals.org Published On :: 2020-04-28T14:32:29-07:00 Previous studies show that 12-week of high-fat diet (HFD) consumption caused not only prediabetes, but also cognitive decline and brain pathologies. Recently, necrostatin-1 (nec-1), a necroptosis inhibitor, showed beneficial effects in brain against stroke. However, the comparative effects of nec-1 and metformin on cognition and brain pathologies in prediabetes have not been investigated. We hypothesized that nec-1 and metformin equally attenuated cognitive decline and brain pathologies in prediabetic rats. Rats (n=32) were fed with either normal diet (ND) or high-fat diet (HFD) for 20 weeks. At week 13, ND-fed rats were given a vehicle (n=8) and HFD-fed rats were randomly assigned into 3 subgroups (n=8/subgroup) with vehicle, nec-1 or metformin for 8 weeks. Metabolic parameters, cognitive function, brain insulin receptor function, synaptic plasticity, dendritic spine density, microglial morphology, brain mitochondrial function, Alzheimer’s protein, and cell death were determined. HFD-fed rats exhibited prediabetes, cognitive decline, and brain pathologies. Nec-1 and metformin equally improved cognitive function, synaptic plasticity, dendritic spine density, microglial morphology, brain mitochondrial function, reduced hyperphosphorylated-tau and necroptosis in HFD-fed rats. Interestingly metformin, but not nec-1, improved brain insulin sensitivity in those rats. In conclusion, necroptosis inhibition directly improved cognition in prediabetic rats without alteration in insulin sensitivity. Full Article
1 The Effects of B1344, a Novel Fibroblast Growth Factor 21 Analog, on Nonalcoholic Steatohepatitis in Nonhuman Primates By diabetes.diabetesjournals.org Published On :: 2020-04-30T07:18:52-07:00 Nonalcoholic steatohepatitis has emerged as a major cause of liver diseases with no effective therapies. Here, we evaluate the efficacies and pharmacokinetics of B1344, a long-acting PEGylated FGF21 analog, in a nongenetically modified nonhuman primate species that underwent liver biopsy, and demonstrate the potential for efficacies in humans. B1344 is sufficient to selectively activate signaling from the βKlotho/FGFR1c receptor complex. In cynomolgus monkeys with nonalcoholic fatty liver disease, administration of B1344 via subcutaneous injection for eleven weeks caused a profound reduction of hepatic steatosis, inflammation and fibrosis, and amelioration of liver injury and hepatocyte death as evidenced by liver biopsy and biochemical analysis. Moreover, improvement of metabolic parameters was observed in the monkey, including reduction of body weight and improvement of lipid profiles and glycemic control. To determine the role of B1344 in the progression of murine NAFLD independent of obesity, administration of B1344 were performed in mice fed with methionine and choline deficiency diet. Consistently, B1344 administration prevented the mice from lipotoxicity damage and nonalcoholic steatohepatitis at a dose-dependent manner. These results provide preclinical validation for an innovative therapeutics to NAFLD, and support further clinical testing of B1344 for treating nonalcoholic steatohepatitis and other metabolic diseases in humans. Full Article
1 Longitudinal Analysis of Serum Cytokine Levels and Gut Microbial Abundance Links IL-17/IL-22 with Clostridia and Insulin Sensitivity in Humans By diabetes.diabetesjournals.org Published On :: 2020-05-04T10:07:04-07:00 Recent studies using mouse models suggest that interaction between the gut microbiome and IL-17/IL-22 producing cells plays a role in the development of metabolic diseases. We investigated this relationship in humans using data from the prediabetes study of the Integrated Human Microbiome Project (iHMP). Specifically, we addressed the hypothesis that early in the onset of metabolic diseases there is a decline in serum levels of IL-17/IL-22, with concomitant changes in the gut microbiome. Clustering iHMP study participants on the basis of longitudinal IL-17/IL-22 profiles identified discrete groups. Individuals distinguished by low levels of IL-17/IL-22 were linked to established markers of metabolic disease, including insulin sensitivity. These individuals also displayed gut microbiome dysbiosis, characterized by decreased diversity, and IL-17/IL-22-related declines in the phylum Firmicutes, class Clostridia, and order Clostridiales. This ancillary analysis of the iHMP data therefore supports a link between the gut microbiome, IL-17/IL-22 and the onset of metabolic diseases. This raises the possibility for novel, microbiome-related therapeutic targets that may effectively alleviate metabolic diseases in humans as they do in animal models. Full Article
1 Erratum. Multiethnic Genome-Wide Association Study of Diabetic Retinopathy Using Liability Threshold Modeling of Duration of Diabetes and Glycemic Control. Diabetes 2019;68:441--456 By diabetes.diabetesjournals.org Published On :: 2020-05-06T12:11:43-07:00 Full Article
1 Dextran Sulfate Protects Pancreatic {beta}-Cells, Reduces Autoimmunity and Ameliorates Type 1 Diabetes By diabetes.diabetesjournals.org Published On :: 2020-05-07T07:53:04-07:00 A failure in self-tolerance leads to autoimmune destruction of pancreatic β-cells and type 1 diabetes (T1D). Low molecular weight dextran sulfate (DS) is a sulfated semi-synthetic polysaccharide with demonstrated cytoprotective and immunomodulatory properties in vitro. However, whether DS can protect pancreatic β-cells, reduce autoimmunity and ameliorate T1D is unknown. Here we report that DS, but not dextran, protects human β-cells against cytokine-mediated cytotoxicity in vitro. DS also protects mitochondrial function and glucose-stimulated insulin secretion and reduces chemokine expression in human islets in a pro-inflammatory environment. Interestingly, daily treatment with DS significantly reduces diabetes incidence in pre-diabetic non-obese diabetic (NOD) mice, and most importantly, reverses diabetes in early-onset diabetic NOD mice. DS decreases β-cell death, enhances islet heparan sulfate (HS)/heparan sulfate proteoglycan (HSPG) expression and preserves β-cell mass and plasma insulin in these mice. DS administration also increases the expression of the inhibitory co-stimulatory molecule programmed death-1 (PD-1) in T-cells, reduces interferon-+ CD4+ and CD8+ T-cells and enhances the number of FoxP3+ cells. Collectively, these studies demonstrate that the action of one single molecule, DS, on β-cell protection, extracellular matrix preservation and immunomodulation can reverse diabetes in NOD mice highlighting its therapeutic potential for the treatment of T1D. Full Article
1 Proline-rich 11 (PRR11) drives F-actin assembly by recruiting the actin-related protein 2/3 complex in human non-small cell lung carcinoma [DNA and Chromosomes] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 The actin cytoskeleton is extremely dynamic and supports diverse cellular functions in many physiological and pathological processes, including tumorigenesis. However, the mechanisms that regulate the actin-related protein 2/3 (ARP2/3) complex and thereby promote actin polymerization and organization in cancer cells are not well-understood. We previously implicated the proline-rich 11 (PRR11) protein in lung cancer development. In this study, using immunofluorescence staining, actin polymerization assays, and siRNA-mediated gene silencing, we uncovered that cytoplasmic PRR11 is involved in F-actin polymerization and organization. We found that dysregulation of PRR11 expression results in F-actin rearrangement and nuclear instability in non-small cell lung cancer cells. Results from molecular mechanistic experiments indicated that PRR11 associates with and recruits the ARP2/3 complex, facilitates F-actin polymerization, and thereby disrupts the F-actin cytoskeleton, leading to abnormal nuclear lamina assembly and chromatin reorganization. Inhibition of the ARP2/3 complex activity abolished irregular F-actin polymerization, lamina assembly, and chromatin reorganization due to PRR11 overexpression. Notably, experiments with truncated PRR11 variants revealed that PRR11 regulates F-actin through different regions. We found that deletion of either the N or C terminus of PRR11 abrogates its effects on F-actin polymerization and nuclear instability and that deletion of amino acid residues 100–184 or 100–200 strongly induces an F-actin structure called the actin comet tail, not observed with WT PRR11. Our findings indicate that cytoplasmic PRR11 plays an essential role in regulating F-actin assembly and nuclear stability by recruiting the ARP2/3 complex in human non-small cell lung carcinoma cells. Full Article
1 The mitochondrial protein PGAM5 suppresses energy consumption in brown adipocytes by repressing expression of uncoupling protein 1 [Metabolism] By feedproxy.google.com Published On :: 2020-04-24T06:08:45-07:00 Accumulating evidence suggests that brown adipose tissue (BAT) is a potential therapeutic target for managing obesity and related diseases. PGAM family member 5, mitochondrial serine/threonine protein phosphatase (PGAM5), is a protein phosphatase that resides in the mitochondria and regulates many biological processes, including cell death, mitophagy, and immune responses. Because BAT is a mitochondria-rich tissue, we have hypothesized that PGAM5 has a physiological function in BAT. We previously reported that PGAM5-knockout (KO) mice are resistant to severe metabolic stress. Importantly, lipid accumulation is suppressed in PGAM5-KO BAT, even under unstressed conditions, raising the possibility that PGAM5 deficiency stimulates lipid consumption. However, the mechanism underlying this observation is undetermined. Here, using an array of biochemical approaches, including quantitative RT-PCR, immunoblotting, and oxygen consumption assays, we show that PGAM5 negatively regulates energy expenditure in brown adipocytes. We found that PGAM5-KO brown adipocytes have an enhanced oxygen consumption rate and increased expression of uncoupling protein 1 (UCP1), a protein that increases energy consumption in the mitochondria. Mechanistically, we found that PGAM5 phosphatase activity and intramembrane cleavage are required for suppression of UCP1 activity. Furthermore, utilizing a genome-wide siRNA screen in HeLa cells to search for regulators of PGAM5 cleavage, we identified a set of candidate genes, including phosphatidylserine decarboxylase (PISD), which catalyzes the formation of phosphatidylethanolamine at the mitochondrial membrane. Taken together, these results indicate that PGAM5 suppresses mitochondrial energy expenditure by down-regulating UCP1 expression in brown adipocytes and that its phosphatase activity and intramembrane cleavage are required for UCP1 suppression. Full Article
1 S-Palmitoylation of the sodium channel Nav1.6 regulates its activity and neuronal excitability [Cell Biology] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 S-Palmitoylation is a reversible post-translational lipid modification that dynamically regulates protein functions. Voltage-gated sodium channels are subjected to S-palmitoylation and exhibit altered functions in different S-palmitoylation states. Our aim was to investigate whether and how S-palmitoylation regulates Nav1.6 channel function and to identify S-palmitoylation sites that can potentially be pharmacologically targeted. Acyl-biotin exchange assay showed that Nav1.6 is modified by S-palmitoylation in the mouse brain and in a Nav1.6 stable HEK 293 cell line. Using whole-cell voltage clamp, we discovered that enhancing S-palmitoylation with palmitic acid increases Nav1.6 current, whereas blocking S-palmitoylation with 2-bromopalmitate reduces Nav1.6 current and shifts the steady-state inactivation in the hyperpolarizing direction. Three S-palmitoylation sites (Cys1169, Cys1170, and Cys1978) were identified. These sites differentially modulate distinct Nav1.6 properties. Interestingly, Cys1978 is exclusive to Nav1.6 among all Nav isoforms and is evolutionally conserved in Nav1.6 among most species. Cys1978 S-palmitoylation regulates current amplitude uniquely in Nav1.6. Furthermore, we showed that eliminating S-palmitoylation at specific sites alters Nav1.6-mediated excitability in dorsal root ganglion neurons. Therefore, our study reveals S-palmitoylation as a potential isoform-specific mechanism to modulate Nav activity and neuronal excitability in physiological and diseased conditions. Full Article
1 Prominins control ciliary length throughout the animal kingdom: New lessons from human prominin-1 and zebrafish prominin-3 [Cell Biology] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 Prominins (proms) are transmembrane glycoproteins conserved throughout the animal kingdom. They are associated with plasma membrane protrusions, such as primary cilia, as well as extracellular vesicles derived thereof. Primary cilia host numerous signaling pathways affected in diseases known as ciliopathies. Human PROM1 (CD133) is detected in both somatic and cancer stem cells and is also expressed in terminally differentiated epithelial and photoreceptor cells. Genetic mutations in the PROM1 gene result in retinal degeneration by impairing the proper formation of the outer segment of photoreceptors, a modified cilium. Here, we investigated the impact of proms on two distinct examples of ciliogenesis. First, we demonstrate that the overexpression of a dominant-negative mutant variant of human PROM1 (i.e. mutation Y819F/Y828F) significantly decreases ciliary length in Madin–Darby canine kidney cells. These results contrast strongly to the previously observed enhancing effect of WT PROM1 on ciliary length. Mechanistically, the mutation impeded the interaction of PROM1 with ADP-ribosylation factor–like protein 13B, a key regulator of ciliary length. Second, we observed that in vivo knockdown of prom3 in zebrafish alters the number and length of monocilia in the Kupffer's vesicle, resulting in molecular and anatomical defects in the left-right asymmetry. These distinct loss-of-function approaches in two biological systems reveal that prom proteins are critical for the integrity and function of cilia. Our data provide new insights into ciliogenesis and might be of particular interest for investigations of the etiologies of ciliopathies. Full Article
1 The cytochrome P450 enzyme CYP24A1 increases proliferation of mutant KRAS-dependent lung adenocarcinoma independent of its catalytic activity [Cell Biology] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 We previously reported that overexpression of cytochrome P450 family 24 subfamily A member 1 (CYP24A1) increases lung cancer cell proliferation by activating RAS signaling and that CYP24A1 knockdown inhibits tumor growth. However, the mechanism of CYP24A1-mediated cancer cell proliferation remains unclear. Here, we conducted cell synchronization and biochemical experiments in lung adenocarcinoma cells, revealing a link between CYP24A1 and anaphase-promoting complex (APC), a key cell cycle regulator. We demonstrate that CYP24A1 expression is cell cycle–dependent; it was higher in the G2-M phase and diminished upon G1 entry. CYP24A1 has a functional destruction box (D-box) motif that allows binding with two APC adaptors, CDC20-homologue 1 (CDH1) and cell division cycle 20 (CDC20). Unlike other APC substrates, however, CYP24A1 acted as a pseudo-substrate, inhibiting CDH1 activity and promoting mitotic progression. Conversely, overexpression of a CYP24A1 D-box mutant compromised CDH1 binding, allowing CDH1 hyperactivation, thereby hastening degradation of its substrates cyclin B1 and CDC20, and accumulation of the CDC20 substrate p21, prolonging mitotic exit. These activities also occurred with a CYP24A1 isoform 2 lacking the catalytic cysteine (Cys-462), suggesting that CYP24A1's oncogenic potential is independent of its catalytic activity. CYP24A1 degradation reduced clonogenic survival of mutant KRAS-driven lung cancer cells, and calcitriol treatment increased CYP24A1 levels and tumor burden in Lsl-KRASG12D mice. These results disclose a catalytic activity-independent growth-promoting role of CYP24A1 in mutant KRAS-driven lung cancer. This suggests that CYP24A1 could be therapeutically targeted in lung cancers in which its expression is high. Full Article
1 Effects of deficiency in the RLBP1-encoded visual cycle protein CRALBP on visual dysfunction in humans and mice [Cell Biology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Mutations in retinaldehyde-binding protein 1 (RLBP1), encoding the visual cycle protein cellular retinaldehyde-binding protein (CRALBP), cause an autosomal recessive form of retinal degeneration. By binding to 11-cis-retinoid, CRALBP augments the isomerase activity of retinoid isomerohydrolase RPE65 (RPE65) and facilitates 11-cis-retinol oxidation to 11-cis-retinal. CRALBP also maintains the 11-cis configuration and protects against unwanted retinaldehyde activity. Studying a sibling pair that is compound heterozygous for mutations in RLBP1/CRALBP, here we expand the phenotype of affected individuals, elucidate a previously unreported phenotype in RLBP1/CRALBP carriers, and demonstrate consistencies between the affected individuals and Rlbp1/Cralbp−/− mice. In the RLBP1/CRALBP-affected individuals, nonrecordable rod-specific electroretinogram traces were recovered after prolonged dark adaptation. In ultrawide-field fundus images, we observed radially arranged puncta typical of RLBP1/CRALBP-associated disease. Spectral domain-optical coherence tomography (SD-OCT) revealed hyperreflective aberrations within photoreceptor-associated bands. In short-wavelength fundus autofluorescence (SW-AF) images, speckled hyperautofluorescence and mottling indicated macular involvement. In both the affected individuals and their asymptomatic carrier parents, reduced SW-AF intensities, measured as quantitative fundus autofluorescence (qAF), indicated chronic impairment in 11-cis-retinal availability and provided information on mutation severity. Hypertransmission of the SD-OCT signal into the choroid together with decreased near-infrared autofluorescence (NIR-AF) provided evidence for retinal pigment epithelial cell (RPE) involvement. In Rlbp1/Cralbp−/− mice, reduced 11-cis-retinal levels, qAF and NIR-AF intensities, and photoreceptor loss were consistent with the clinical presentation of the affected siblings. These findings indicate that RLBP1 mutations are associated with progressive disease involving RPE atrophy and photoreceptor cell degeneration. In asymptomatic carriers, qAF disclosed previously undetected visual cycle deficiency. Full Article
1 SUMOylation of the transcription factor ZFHX3 at Lys-2806 requires SAE1, UBC9, and PIAS2 and enhances its stability and function in cell proliferation [Protein Synthesis and Degradation] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 SUMOylation is a posttranslational modification (PTM) at a lysine residue and is crucial for the proper functions of many proteins, particularly of transcription factors, in various biological processes. Zinc finger homeobox 3 (ZFHX3), also known as AT motif-binding factor 1 (ATBF1), is a large transcription factor that is active in multiple pathological processes, including atrial fibrillation and carcinogenesis, and in circadian regulation and development. We have previously demonstrated that ZFHX3 is SUMOylated at three or more lysine residues. Here, we investigated which enzymes regulate ZFHX3 SUMOylation and whether SUMOylation modulates ZFHX3 stability and function. We found that SUMO1, SUMO2, and SUMO3 each are conjugated to ZFHX3. Multiple lysine residues in ZFHX3 were SUMOylated, but Lys-2806 was the major SUMOylation site, and we also found that it is highly conserved among ZFHX3 orthologs from different animal species. Using molecular analyses, we identified the enzymes that mediate ZFHX3 SUMOylation; these included SUMO1-activating enzyme subunit 1 (SAE1), an E1-activating enzyme; SUMO-conjugating enzyme UBC9 (UBC9), an E2-conjugating enzyme; and protein inhibitor of activated STAT2 (PIAS2), an E3 ligase. Multiple analyses established that both SUMO-specific peptidase 1 (SENP1) and SENP2 deSUMOylate ZFHX3. SUMOylation at Lys-2806 enhanced ZFHX3 stability by interfering with its ubiquitination and proteasomal degradation. Functionally, Lys-2806 SUMOylation enabled ZFHX3-mediated cell proliferation and xenograft tumor growth of the MDA-MB-231 breast cancer cell line. These findings reveal the enzymes involved in, and the functional consequences of, ZFHX3 SUMOylation, insights that may help shed light on ZFHX3's roles in various cellular and pathophysiological processes. Full Article
1 The short variant of optic atrophy 1 (OPA1) improves cell survival under oxidative stress [Bioenergetics] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Optic atrophy 1 (OPA1) is a dynamin protein that mediates mitochondrial fusion at the inner membrane. OPA1 is also necessary for maintaining the cristae and thus essential for supporting cellular energetics. OPA1 exists as membrane-anchored long form (L-OPA1) and short form (S-OPA1) that lacks the transmembrane region and is generated by cleavage of L-OPA1. Mitochondrial dysfunction and cellular stresses activate the inner membrane–associated zinc metallopeptidase OMA1 that cleaves L-OPA1, causing S-OPA1 accumulation. The prevailing notion has been that L-OPA1 is the functional form, whereas S-OPA1 is an inactive cleavage product in mammals, and that stress-induced OPA1 cleavage causes mitochondrial fragmentation and sensitizes cells to death. However, S-OPA1 contains all functional domains of dynamin proteins, suggesting that it has a physiological role. Indeed, we recently demonstrated that S-OPA1 can maintain cristae and energetics through its GTPase activity, despite lacking fusion activity. Here, applying oxidant insult that induces OPA1 cleavage, we show that cells unable to generate S-OPA1 are more sensitive to this stress under obligatory respiratory conditions, leading to necrotic death. These findings indicate that L-OPA1 and S-OPA1 differ in maintaining mitochondrial function. Mechanistically, we found that cells that exclusively express L-OPA1 generate more superoxide and are more sensitive to Ca2+-induced mitochondrial permeability transition, suggesting that S-OPA1, and not L-OPA1, protects against cellular stress. Importantly, silencing of OMA1 expression increased oxidant-induced cell death, indicating that stress-induced OPA1 cleavage supports cell survival. Our findings suggest that S-OPA1 generation by OPA1 cleavage is a survival mechanism in stressed cells. Full Article
1 An arrestin-1 surface opposite of its interface with photoactivated rhodopsin engages with enolase-1 [Protein Structure and Folding] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Arrestin-1 is the arrestin family member responsible for inactivation of the G protein–coupled receptor rhodopsin in photoreceptors. Arrestin-1 is also well-known to interact with additional protein partners and to affect other signaling cascades beyond phototransduction. In this study, we investigated one of these alternative arrestin-1 binding partners, the glycolysis enzyme enolase-1, to map the molecular contact sites between these two proteins and investigate how the binding of arrestin-1 affects the catalytic activity of enolase-1. Using fluorescence quench protection of strategically placed fluorophores on the arrestin-1 surface, we observed that arrestin-1 primarily engages enolase-1 along a surface that is opposite of the side of arrestin-1 that binds photoactivated rhodopsin. Using this information, we developed a molecular model of the arrestin-1–enolase-1 complex, which was validated by targeted substitutions of charge-pair interactions. Finally, we identified the likely source of arrestin's modulation of enolase-1 catalysis, showing that selective substitution of two amino acids in arrestin-1 can completely remove its effect on enolase-1 activity while still remaining bound to enolase-1. These findings open up opportunities for examining the functional effects of arrestin-1 on enolase-1 activity in photoreceptors and their surrounding cells. Full Article
1 Targeting the polyamine pathway—“a means” to overcome chemoresistance in triple-negative breast cancer [Cell Biology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 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. Full Article
1 Structural basis of specific inhibition of extracellular activation of pro- or latent myostatin by the monoclonal antibody SRK-015 [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 Myostatin (or growth/differentiation factor 8 (GDF8)) is a member of the transforming growth factor β superfamily of growth factors and negatively regulates skeletal muscle growth. Its dysregulation is implicated in muscle wasting diseases. SRK-015 is a clinical-stage mAb that prevents extracellular proteolytic activation of pro- and latent myostatin. Here we used integrated structural and biochemical approaches to elucidate the molecular mechanism of antibody-mediated neutralization of pro-myostatin activation. The crystal structure of pro-myostatin in complex with 29H4-16 Fab, a high-affinity variant of SRK-015, at 2.79 Å resolution revealed that the antibody binds to a conformational epitope in the arm region of the prodomain distant from the proteolytic cleavage sites. This epitope is highly sequence-divergent, having only limited similarity to other closely related members of the transforming growth factor β superfamily. Hydrogen/deuterium exchange MS experiments indicated that antibody binding induces conformational changes in pro- and latent myostatin that span the arm region, the loops contiguous to the protease cleavage sites, and the latency-associated structural elements. Moreover, negative-stain EM with full-length antibodies disclosed a stable, ring-like antigen–antibody structure in which the two Fab arms of a single antibody occupy the two arm regions of the prodomain in the pro- and latent myostatin homodimers, suggesting a 1:1 (antibody:myostatin homodimer) binding stoichiometry. These results suggest that SRK-015 binding stabilizes the latent conformation and limits the accessibility of protease cleavage sites within the prodomain. These findings shed light on approaches that specifically block the extracellular activation of growth factors by targeting their precursor forms. Full Article
1 Structures of the MHC-I molecule BF2*1501 disclose the preferred presentation of an H5N1 virus-derived epitope [Protein Structure and Folding] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 Lethal infections by strains of the highly-pathogenic avian influenza virus (HPAIV) H5N1 pose serious threats to both the poultry industry and public health worldwide. A lack of confirmed HPAIV epitopes recognized by cytotoxic T lymphocytes (CTLs) has hindered the utilization of CD8+ T-cell–mediated immunity and has precluded the development of effectively diversified epitope-based vaccination approaches. In particular, an HPAIV H5N1 CTL-recognized epitope based on the peptide MHC-I–β2m (pMHC-I) complex has not yet been designed. Here, screening a collection of selected peptides of several HPAIV strains against a specific pathogen-free pMHC-I (pBF2*1501), we identified a highly-conserved HPAIV H5N1 CTL epitope, named HPAIV–PA123–130. We determined the structure of the BF2*1501–PA123–130 complex at 2.1 Å resolution to elucidate the molecular mechanisms of a preferential presentation of the highly-conserved PA123–130 epitope in the chicken B15 lineage. Conformational characteristics of the PA123–130 epitope with a protruding Tyr-7 residue indicated that this epitope has great potential to be recognized by specific TCRs. Moreover, significantly increased numbers of CD8+ T cells specific for the HPAIV–PA123–130 epitope in peptide-immunized chickens indicated that a repertoire of CD8+ T cells can specifically respond to this epitope. We anticipate that the identification and structural characterization of the PA123–130 epitope reported here could enable further studies of CTL immunity against HPAIV H5N1. Such studies may aid in the development of vaccine development strategies using well-conserved internal viral antigens in chickens. Full Article
1 Structure of an ancestral mammalian family 1B1 cytochrome P450 with increased thermostability [Enzymology] By feedproxy.google.com Published On :: 2020-04-24T06:08:45-07:00 Mammalian cytochrome P450 enzymes often metabolize many pharmaceuticals and other xenobiotics, a feature that is valuable in a biotechnology setting. However, extant P450 enzymes are typically relatively unstable, with T50 values of ∼30–40 °C. Reconstructed ancestral cytochrome P450 enzymes tend to have variable substrate selectivity compared with related extant forms, but they also have higher thermostability and therefore may be excellent tools for commercial biosynthesis of important intermediates, final drug molecules, or drug metabolites. The mammalian ancestor of the cytochrome P450 1B subfamily was herein characterized structurally and functionally, revealing differences from the extant human CYP1B1 in ligand binding, metabolism, and potential molecular contributors to its thermostability. Whereas extant human CYP1B1 has one molecule of α-naphthoflavone in a closed active site, we observed that subtle amino acid substitutions outside the active site in the ancestor CYP1B enzyme yielded an open active site with four ligand copies. A structure of the ancestor with 17β-estradiol revealed only one molecule in the active site, which still had the same open conformation. Detailed comparisons between the extant and ancestor forms revealed increases in electrostatic and aromatic interactions between distinct secondary structure elements in the ancestral forms that may contribute to their thermostability. To the best of our knowledge, this represents the first structural evaluation of a reconstructed ancestral cytochrome P450, revealing key features that appear to contribute to its thermostability. Full Article
1 An arrestin-1 surface opposite of its interface with photoactivated rhodopsin engages with enolase-1 [Protein Structure and Folding] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Arrestin-1 is the arrestin family member responsible for inactivation of the G protein–coupled receptor rhodopsin in photoreceptors. Arrestin-1 is also well-known to interact with additional protein partners and to affect other signaling cascades beyond phototransduction. In this study, we investigated one of these alternative arrestin-1 binding partners, the glycolysis enzyme enolase-1, to map the molecular contact sites between these two proteins and investigate how the binding of arrestin-1 affects the catalytic activity of enolase-1. Using fluorescence quench protection of strategically placed fluorophores on the arrestin-1 surface, we observed that arrestin-1 primarily engages enolase-1 along a surface that is opposite of the side of arrestin-1 that binds photoactivated rhodopsin. Using this information, we developed a molecular model of the arrestin-1–enolase-1 complex, which was validated by targeted substitutions of charge-pair interactions. Finally, we identified the likely source of arrestin's modulation of enolase-1 catalysis, showing that selective substitution of two amino acids in arrestin-1 can completely remove its effect on enolase-1 activity while still remaining bound to enolase-1. These findings open up opportunities for examining the functional effects of arrestin-1 on enolase-1 activity in photoreceptors and their surrounding cells. Full Article