TREX1 is expressed by microglia in normal human brain and increases in regions affected by ischemia

BACKGROUND: Mutations in the three-prime repair exonuclease 1 (TREX1) gene have been associated with neurological diseases, including Retinal Vasculopathy with Cerebral Leukoencephalopathy (RVCL). However, the endogenous expression of TREX1 in human brain has not been studied. METHODS: We produced a rabbit polyclonal antibody (pAb) to TREX1 to characterize TREX1 by Western blotting (WB) of cell lysates from normal controls and subjects carrying an RVCL frame-shift mutation. Dual staining was performed to determine cell types expressing TREX1 in human brain tissue. TREX1 distribution in human brain was further evaluated by immunohistochemical analyses of formalin-fixed, paraffin-embedded samples from normal controls and patients with RVCL and ischemic stroke. RESULTS: After validating the specificity of our anti-TREX1 rabbit pAb, WB analysis was utilized to detect the endogenous wild-type and frame-shift mutant of TREX1 in cell lysates. Dual staining in human brain tissues from patients with RVCL and normal controls localized TREX1 to a subset of microglia and macrophages. Quantification of immunohistochemical staining of the cerebral cortex revealed that TREX1 CONCLUSIONS: TREX1 is expressed by a subset of microglia in normal human brain, often in close proximity to the microvasculature, and increases in the setting of ischemic lesions. These findings suggest a role for TREX

A C3(H20) recycling pathway is a component of the intracellular complement system

An intracellular complement system (ICS) has recently been described in immune and nonimmune human cells. This system can be activated in a convertase-independent manner from intracellular stores of the complement component C3. The source of these stores has not been rigorously investigated. In the present study, Western blotting identified a band corresponding to C3 in freshly isolated human peripheral blood cells that was absent in corresponding cell lines. One difference between native cells and cell lines was the time absent from a fluid-phase complement source; therefore, we hypothesized that loading C3 from plasma was a route of establishing intracellular C3 stores. We found that many types of human cells specifically internalized C3(H(2)O), the hydrolytic product of C3, and not native C3, from the extracellular milieu. Uptake was rapid, saturable, and sensitive to competition with unlabeled C3(H(2)O), indicating a specific mechanism of loading. Under steady-state conditions, approximately 80% of incorporated C3(H(2)O) was returned to the extracellular space. These studies identify an ICS recycling pathway for C3(H(2)O). The loaded C3(H(2)O) represents a source of C3a, and its uptake altered the cytokine profile of activated CD4(+) T cells. Importantly, these results indicate that the impact of soluble plasma factors should be considered when performing in vitro studies assessing cellular immune function

Regulators of complement activity mediate inhibitory mechanisms through a common C3b‐binding mode

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Convergence of TOR-nitrogen and Snf1-glucose signaling pathways onto Gln3

Carbon and nitrogen are two basic nutrient sources for cellular organisms. They supply precursors for energy metabolism and metabolic biosynthesis. In the yeast Saccharomyces cerevisiae, distinct sensing and signaling pathways have been described that regulate gene expression in response to the quality of carbon and nitrogen sources, respectively. Gln3 is a GATA-type transcription factor of nitrogen catabolite-repressible (NCR) genes. Previous observations indicate that the quality of nitrogen sources controls the phosphorylation and cytoplasmic retention of Gln3 via the target of rapamycin (TOR) protein. In this study, we show that glucose also regulates Gln3 phosphorylation and subcellular localization, which is mediated by Snf1, the yeast homolog of AMP-dependent protein kinase and a cytoplasmic glucose sensor. Our data show that glucose and nitrogen signaling pathways converge onto Gln3, which may be critical for both nutrient sensing and starvation responses

Timing and mechanism of conceptus demise in a complement regulatory membrane protein deficient mouse

PROBLEM: Crry is a widely expressed type 1 transmembrane complement regulatory protein in rodents which protects self-tissue by downregulating C3 activation. Crry METHOD OF STUDY: We investigated the basis of Crry RESULTS: We narrowed the critical period of the complement effect from 6.5 to 8.5 days post-coitus (dpc), which is immediately after the conceptus is exposed to maternal blood. Deposition by 5.5 dpc of maternal C3b on the placental vasculature lacking Crry CONCLUSION: Our data are most consistent with the deposition of C3b being responsible for the failure of the allantois to fuse to the chorion leading to subsequent conceptus demise

Influenza and SARS-coronavirus activating proteases TMPRSS2 and HAT are expressed at multiple sites in human respiratory and gastrointestinal tracts.

The type II transmembrane serine proteases TMPRSS2 and HAT activate influenza viruses and the SARS-coronavirus (TMPRSS2) in cell culture and may play an important role in viral spread and pathogenesis in the infected host. However, it is at present largely unclear to what extent these proteases are expressed in viral target cells in human tissues. Here, we show that both HAT and TMPRSS2 are coexpressed with 2,6-linked sialic acids, the major receptor determinant of human influenza viruses, throughout the human respiratory tract. Similarly, coexpression of ACE2, the SARS-coronavirus receptor, and TMPRSS2 was frequently found in the upper and lower aerodigestive tract, with the exception of the vocal folds, epiglottis and trachea. Finally, activation of influenza virus was conserved between human, avian and porcine TMPRSS2, suggesting that this protease might activate influenza virus in reservoir-, intermediate- and human hosts. In sum, our results show that TMPRSS2 and HAT are expressed by important influenza and SARS-coronavirus target cells and could thus support viral spread in the human host

Renal function stratified dose comparisons of eplerenone versus placebo in the EMPHASIS-HF trial.

BACKGROUND: Current heart failure guidelines recommend target eplerenone dose of 50 mg/day. We have examined the effect of different eplerenone doses based on pre-specified renal function stratification in the Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF). METHODS AND RESULTS: In EMPHASIS-HF, the target dose of eplerenone/placebo was stratified at randomization according to estimated glomerular filtration rate (eGFR): 50 mg/day if eGFR ≥ 50 mL/min/1.73 m2 and ≤ 25 mg/day if eGFR 30-49 mL/min/1.73 m2 . Patients remained within these dose ranges during the trial (as per stratification). The primary outcome was a composite of heart failure hospitalization or cardiovascular mortality. Eplerenone was superior to placebo within each respective eGFR stratum [eplerenone vs. placebo in the eGFR ≥ 50 mL/min/1.73 m2 stratum: hazard ratio (HR) 0.58, 95% confidence interval (CI) 0.45-0.74; and eplerenone vs. placebo in the eGFR 30-49 mL/min/1.73 m2 stratum: HR 0.62, 95% CI 0.49-0.78; Pinteraction  = 0.89]. Despite receiving lower eplerenone doses, patients in the eGFR 30-49 mL/min/1.73 m2 stratum more often had hyperkalaemia, renal failure events, and drug discontinuation. CONCLUSION: In EMPHASIS-HF the eplerenone dose was stratified according to renal function and the treatment effect was not influenced by renal function: 25 mg/day in patients with eGFR 30-49 mL/min/1.73 m2 was as effective as 50 mg/day in patients with eGFR > =50 mL/min/1.73 m2 . However, patients with impaired renal function experienced more adverse events, despite reveiving lower eplerenone doses. Current guidelines do not recommend tailoring the dose of eplereone according to renal function but the current data suggest they should

Why don't we share data and code? Perceived barriers and benefits to public archiving practices

The biological sciences community is increasingly recognizing the value ofopen, reproducible and transparent research practices for science and societyat large. Despite this recognition, many researchers fail to share their dataand code publicly. This pattern may arise from knowledge barriers abouthow to archive data and code, concerns about its reuse, and misalignedcareer incentives. Here, we define, categorize and discuss barriers to dataand code sharing that are relevant to many research fields. We explorehow real and perceived barriers might be overcome or reframed in thelight of the benefits relative to costs. By elucidating these barriers and thecontexts in which they arise, we can take steps to mitigate them and alignour actions with the goals of open science, both as individual scientistsand as a scientific community

Prognostic importance of quantitative analysis of coronary cineangiograms

Many studies have shown the prognostic value of angiographic data, but few have examined quantitative parameters of wall motion and shape or coronary stenosis severity. To determine whether these parameters have prognostic importance, baseline angiograms of 283 patients with up to 11.2 years (mean 8.3) of follow-up were quantitated. Event-free survival curves were constructed using log-rank testing. These indexes were also considered in 2 predictive models (Cox regression models): 1 with ("clinical") and 1 without ("quantitative") subjective angiographic analysis and clinical information. Regional shape (anterior and inferior walls) and motion (anterior wall only) indexes were predictive of event-free survival when considered singly. But these parameters were not of independent prognostic importance in the regression models. The most important independent parameters in the quantitative model for predicting overall cardiac mortality or an initial lethal cardiac event were the ejection fraction and the percent diameter narrowing of each major coronary artery. Myocardial infarction was predicted by the percent diameter stenosis of the left main and left anterior descending arteries but not the ejection fraction. In the clinical model, the factors of overriding prognostic importance were the ejection fraction and the subjective determination of the number of vessels involved with "significant" stenoses. Quantitative coronary arteriography still contributed independent prognostic value. Thus, quantification of the ejection fraction and severity of coronary lesions were of independent, prognostic importance, whereas indexes of regional function and shape were not.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30104/1/0000476.pd