Human papillomavirus E7 oncoprotein induces KDM6A and KDM6B histone demethylase expression and causes epigenetic reprogramming
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Authors: McLaughlin-Drubin, Margaret E.; Crum, Christopher P.; Muengera, Karl
Abstract
Despite the availability of vaccines, human papillomavirus (HPV) infections remain a cause of significant cancer morbidity and mortality. We have previously shown that HPV16 E7 associates with and diminishes E2F6-containing polycomb repressive complexes. Here, we show that repressive trimethyl marks on lysine 27 of histone 3, which are necessary for binding of polycomb repressive complexes, are decreased in HPV16 E7-expressing cells and HPV16-positive cervical lesions. This is caused by transcriptional induction of the KDM6A and KDM6B histone 3 lysine 27-specific demethylases. HPV16 E7-mediated KDM6B induction accounts for expression of the cervical cancer biomarker, p16(INK4A). Moreover, KDM6A- and KDM6B-responsive Homeobox genes are expressed at significantly higher levels, suggesting that HPV16 E7 results in reprogramming of host epithelial cells. These effects are independent of the ability of E7 to inhibit the retinoblastoma tumor suppressor protein. Most importantly, these effects are reversed when E7 expression is silenced, indicating that this pathway may have prognostic and/or therapeutic significance.
Adolescent Alcohol Exposure Epigenetically Suppresses Amygdala Arc Enhancer RNA Expression to Confer Adult Anxiety Susceptibility
BIOLOGICAL PSYCHIATRY
Authors: Kyzar, Evan J.; Zhang, Huaibo; Pandey, Subhash C.
Abstract
BACKGROUND: Adolescent intermittent ethanol (AIE) exposure is an emerging risk factor for adult psychopathology, such as anxiety disorders. Enhancer RNAs (eRNAs) are short noncoding RNAs transcribed from enhancer regions that regulate synaptic plasticity-associated gene expression, including Arc, but their role in AIE-induced susceptibility to anxiety in adulthood is unknown. METHODS: Rats were exposed to AIE (ethanol exposure 2 days on/off) or intermittent normal saline during postnatal days 28 to 41 and allowed to grow to adulthood for analysis of behavior and biochemical measures. Some AIE rats and rats with intermittent normal saline exposure were exposed to an acute challenge with ethanol in adulthood. Cohorts of alcohol-naive adult rats were cannulated in the central nucleus of amygdala and infused with either Kdm6b small interfering RNA or an antisense locked nucleic acid oligonucleotide specific to Arc eRNA before behavioral and biochemical analysis. RESULTS: AIE adult rats displayed heightened anxiety and decreased Arc eRNA expression, which is regulated epigenetically through decreased Kdm6b expression. This triggered condensed chromatin at the synaptic activity response element site and promoter of the Arc gene, facilitating increased negative elongation factor binding to the Arc promoter and decreasing Arc expression in the amygdala. Knockdown of Kdm6b or Arc eRNA expression in the central nucleus of amygdala provoked anxiety in alcohol-ndive adult rats and recapitulated the molecular and epigenetic phenotypes of AIE. CONCLUSIONS: These data suggest that eRNA regulation via epigenetic reprogramming in the amygdala, particularly at the Arc synaptic activity response element site, contributes to adult anxiety after adolescent alcohol exposure.