Eboo Pharmaceuticals (United States)

Polycomb group proteins maintain gene expression patterns established during early development, with Polycomb repressive complex 2 (PRC2) methyltransferase being a key regulator of cell differentiation, identity, and plasticity. Consequently, extensive somatic mutations in PRC2, including gain or loss of function (GOF or LOF), are observed in human cancers. The regulation of chromatin structure by PRC2 is critically dependent on its enhancer of zeste homolog 2 (EZH2) subunit, which catalyzes the methylation of histone H3 lysine 27 (H3K27). Recent structural studies of PRC2 revealed extensive conformational changes in the noncatalytic EZH2 N-terminal SANT1-binding domain (SBD) during PRC2 activation, though the functional significance remains unclear. Here, we investigated how the SBD regulates PRC2 function. The domain is highly conserved in metazoans and dispensable for PRC2 assembly and chromatin localization yet is required for genome-wide histone H3K27 methylation. Furthermore, we show that an intact SBD is necessary for the proliferation of EZH2-addicted lymphomas, and its deletion in the presence of EZH2 GOF mutations inhibits cancer cell growth. These observations provide new insights into the regulation of PRC2 activity in normal development and malignancy.

This document presents the ICRP's updated vision on “Areas of Research to Support the System of Radiological Protection”, which have been previously published in 2017. It aims to complement the research priorities promoted by other relevant international organisations, with the specificity of placing them in the perspective of the evolution of the System of Radiological Protection. This document contributes to the process launched by ICRP to review and revise the System of Radiological Protection that will update the 2007 General Recommendations in ICRP Publication 103.

ObjectivesTo assess the risk of chronic kidney disease (CKD) associated with tenofovir disoproxil fumarate (TDF) use by baseline D:A:D CKD risk score.MethodsAdult antiretroviral therapy (ART)‐naïve people living with HIV (PLWH) initiating treatment, with estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2, were identified in the OPERA cohort. CKD was defined as two or more consecutive eGFR < 60 mL/min/1.73 m2, > 90 days apart. Associations between TDF use, baseline D:A:D CKD risk and incident CKD were assessed with incidence rates (IRs; Poisson regression) and adjusted pooled logistic regression. The impact of pharmacoenhancers on the observed association between TDF and CKD was also evaluated.ResultsOf 9802 PLWH included, 6222 initiated TDF and 3580 did not (76% and 79% low D:A:D CKD risk, respectively). Overall, 125 CKD events occurred over 24 382 person‐years of follow‐up. Within strata of D:A:D CKD risk score, IRs were similar across TDF exposure, with high baseline CKD risk associated with highest incidence. Compared with the low‐risk group without TDF, there was no statistical difference in odds of incident CKD in the low‐risk group with TDF (adjusted odds ratio = 0.55, 95% confidence interval: 0.19–1.54). Odds of incident CKD did not differ statistically significantly by pharmacoenhancer exposure, with or without TDF.ConclusionsIn this large cohort of ART‐naïve PLWH, incident CKD following ART initiation was infrequent and strongly associated with baseline CKD risk. TDF‐containing regimens did not increase the odds of CKD in those with a low baseline D:A:D CKD risk, the largest group of ART‐naïve PLWH, and may remain a viable treatment option in appropriate settings.

ObjectivesThe aim of the study was to assess the validity of an easy‐to‐calculate chronic kidney disease (CKD) risk score developed by the Data Collection on Adverse Events of Anti‐HIV Drugs (D:A:D) group in a longitudinal observational study of people living with HIV (PLWH) in the USA.MethodsPLWH (2002–2016) without prior exposure to potentially nephrotoxic antiretroviral agents and with at least three estimated glomerular filtration rate (eGFR) test results were identified in the Observational Pharmaco‐Epidemiology Research and Analysis (OPERA®) cohort. Three samples were drawn independently using the same eligibility criteria but each using a different eGFR equation, specifically the Cockcroft–Gault (C‐G), Modification of Diet in Renal Disease (MDRD) or Chronic Kidney Disease Epidemiology Collaboration (CKD‐EPI) eGFR estimation method. Full and short D:A:D risk scores were applied. CKD was defined as a confirmed decrease in eGFR to < 60 mL/min/1.73 m2 (stages 3–5). Poisson models estimated the association between CKD incidence and a one‐point increase in the continuous risk score. The incidence rate ratio (IRR), adjusted IRR (aIRR), and Harrell's discrimination statistic were used to assess validity.ResultsThere were 19 444, 22 727 and 22 748 PLWH in the OPERA C‐G, CKD‐EPI and MDRD samples, respectively. The median (minimum–maximum) follow‐up duration was 6.1 (0.3–9.1) years in the D:A:D cohort and ranged from 3.2 to 3.5 (0.2–15.5) years in the OPERA validation samples. The observation time for the majority of PLWH in the D:A:D cohort began prior to 2006, in stark contrast to the OPERA validation samples, where the majority of PLWH were observed after 2011. The CKD incidence ranged from 7.3 per 1000 person‐years [95% confidence interval (CI) 6.8, 7.9 per 1000 person‐years] in OPERA C‐G to 11.0 (95% CI 10.4, 11.6 per 1000 person‐years) in OPERA MDRD. In OPERA samples, IRRs by risk group and adjusted IRRs (full risk score) were similar to those in the D:A:D derivation cohort (adjusted IRR 1.3; 95% CI 1.3, 1.3). Harrell's c‐statistic ranged from 0.87 to 0.92 in the OPERA samples, comparable to that in the derivation cohort (0.92). Results for short scores were similar.ConclusionsThe findings support the validity of the D:A:D risk scoring method for assessing CKD (stages 3–5) probability in an exclusively USA‐based sample regardless of eGFR method.

Epigenetic enzymes oversee long‐term changes in gene expression by integrating genetic and environmental cues. While there are hundreds of enzymes that control histone and DNA modifications, their potential roles in substance abuse and alcohol dependence remain underexplored. A few recent studies have suggested that epigenetic processes could underlie transcriptomic and behavioral hallmarks of alcohol addiction. In the present study, we sought to identify epigenetic enzymes in the brain that are dysregulated during protracted abstinence as a consequence of chronic and intermittent alcohol exposure. Through quantitative mRNA expression analysis of over 100 epigenetic enzymes, we identified 11 that are significantly altered in alcohol‐dependent rats compared with controls. Follow‐up studies of one of these enzymes, the histone demethylase KDM6B, showed that this enzyme exhibits region‐specific dysregulation in the prefrontal cortex and nucleus accumbens of alcohol‐dependent rats. KDM6B was also upregulated in the human alcoholic brain. Upregulation of KDM6B protein in alcohol‐dependent rats was accompanied by a decrease of trimethylation levels at histone H3, lysine 27 (H3K27me3), consistent with the known demethylase specificity of KDM6B. Subsequent epigenetic (chromatin immunoprecipitation [ChIP]–sequencing) analysis showed that alcohol‐induced changes in H3K27me3 were significantly enriched at genes in the IL‐6 signaling pathway, consistent with the well‐characterized role of KDM6B in modulation of inflammatory responses. Knockdown of KDM6B in cultured microglial cells diminished IL‐6 induction in response to an inflammatory stimulus. Our findings implicate a novel KDM6B‐mediated epigenetic signaling pathway integrated with inflammatory signaling pathways that are known to underlie the development of alcohol addiction.

The current high-stakes testing environment is compelling many educators to teach reading in programmatic ways. This type of teaching contrasts research on effective literacy instruction. This article describes a Title I elementary school's effort to improve literacy instruction not by adopting a program but rather by providing professional development emphasizing project-based literacy instruction. A teacher research study examined how teachers implemented project-based literacy instruction and how they felt about using such instruction. This study found several themes in (a) the types of projects teachers implemented, (b) what went well in using project-based instruction, and (c) obstacles teachers faced in implementing this type of instruction.

These breath-simulation experiments suggest that only about 20% of the nominal 15-microg arformoterol dose was emitted from the nebulizer apparatus with each of the 4 tidal breathing patterns studied, and that a longer inspiratory phase was associated with greater inhaled dose.

Atrazine is one of the most widely used herbicides in the United States. Introduced in the 1950s, atrazine is a broad spectrum herbicide with current total annual use of approximately 76 million pounds of active ingredient. Frogs exhibit gonadal malformations and/or variations in normal hormone production following exposure to atrazine. Based on in vitro studies using H295R cells, it has been speculated that these effects are the result of the influence of atrazine on aromatase (enzyme responsible for the conversion of androgens into estrogens) expression and/or activity; however, this hypothesis remains controversial. In order to determine if/how atrazine is affecting aromatase activity and reproductive function, the specific molecular mechanisms which are targeted by atrazine need to be determined. The orphan nuclear receptor steroidogenic factor 1 (SF-1) regulates the transcription of a large number of genes involved in steroidogenesis and reproduction. SF-1 binds its response element and regulates transcription constitutively; however, ligand binding may enhance SF-1 activity. It has been shown that atrazine increases SF-1 expression, and binds to SF-1. Since SF-1 is located in the rat aromatase promoter, and has been localized to rat granulosa and theca cells, atrazine may induce binding and activation of the aromatase promoter, leading to an increase in aromatase activity. The current studies were conducted to determine if aromatase expression and activity could be measured in rat granulosa cells in culture and to determine the effects of atrazine on these measures. Twenty-seven day old Wistar rats were injected with 20 IU of PMSG to stimulate follicular development. After 48 hours the rats were killed and ovaries collected. Granulosa cells were isolated and placed in culture with vehicle alone (0.3 % ethanol), atrazine (1, 10 or 30 µM), testosterone (0.017 µM), or 4-hydroxyandrostenedione (10 µM). Following 24 hours in culture some of the media and granulosa cells were collected for radio-immunoassays (RIAs) and real time PCR, respectively, and other cells remained in culture to measure aromatase activity using the tritiated water assay. Atrazine at all three concentrations did not affect estradiol production; however, atrazine at 10 and 30 µM significantly increased progesterone concentrations as compared to controls (p ≤ 0.05). Aromatase (CYP19) and SF-1 expression of mRNA were not significantly affected by any of the atrazine treatments. In summary, our results show that it is possible to detect aromatase activity from granulosa cells in culture: however, it has yet to be determined if atrazine affects aromatase activity in granulosa cell cultures. These results suggest that atrazine does not affect follicular estrogen production, but that it may affect luteinization or luteal hormone production. This abstract does not necessarily reflect EPA policy.