Acute and Chronic Electroconvulsive Seizures (ECS) Differentially Regulate the Expression of Epigenetic Machinery in the Adult Rat Hippocampus.

BACKGROUND: Electroconvulsive seizure treatment is a fast-acting antidepressant therapy that evokes rapid transcriptional, neurogenic, and behavioral changes. Epigenetic mechanisms contribute to altered gene regulation, which underlies the neurogenic and behavioral effects of electroconvulsive seizure. We hypothesized that electroconvulsive seizure may modulate the expression of epigenetic machinery, thus establishing potential alterations in the epigenetic landscape. METHODS: We examined the influence of acute and chronic electroconvulsive seizure on the gene expression of histone modifiers, namely histone acetyltransferases, histone deacetylases, histone methyltransferases, and histone (lysine) demethylases as well as DNA modifying enzymes, including DNA methyltransferases, DNA demethylases, and methyl-CpG-binding proteins in the hippocampi of adult male Wistar rats using quantitative real time-PCR analysis. Further, we examined the influence of acute and chronic electroconvulsive seizure on global and residue-specific histone acetylation and methylation levels within the hippocampus, a brain region implicated in the cellular and behavioral effects of electroconvulsive seizure. RESULTS: Acute and chronic electroconvulsive seizure induced a primarily unique, and in certain cases bidirectional, regulation of histone and DNA modifiers, and methyl-CpG-binding proteins, with an overlapping pattern of gene regulation restricted to Sirt4, Mll3, Jmjd3, Gadd45b, Tet2, and Tet3. Global histone acetylation and methylation levels were predominantly unchanged, with the exception of a significant decline in H3K9 acetylation in the hippocampus following chronic electroconvulsive seizure. CONCLUSIONS: Electroconvulsive seizure treatment evokes the transcriptional regulation of several histone and DNA modifiers, and methyl-CpG-binding proteins within the hippocampus, with a predominantly distinct pattern of regulation induced by acute and chronic electroconvulsive seizure.

Early stress evokes dysregulation of histone modifiers in the medial prefrontal cortex across the life span.

Early stress has been hypothesized to recruit epigenetic mechanisms to mediate persistent molecular, cellular, and behavioral changes. Here, we have examined the consequence of the early life stress of maternal separation (ES) on the gene expression of several histone modifiers that regulate histone acetylation and methylation within the medial prefrontal cortex (mPFC), a key limbic brain region that regulates stress responses and mood-related behavior. ES animals exhibit gene regulation of both writer (histone acetyltransferases and histone methyltransferases) and eraser (histone deacetylases and histone lysine demethylases) classes of histone modifiers. While specific histone modifiers (Kat2a, Smyd3, and Suv420h1) and the sirtuin, Sirt4 were downregulated across life within the mPFC of ES animals, namely at postnatal Day 21, 2 months, and 15 months of age, we also observed gene regulation restricted to these specific time points. Despite the decline noted in expression of several histone modifiers within the mPFC following ES, this was not accompanied by any change in global or residue-specific H3 acetylation and methylation. Our findings indicate that ES results in the regulation of several histone modifiers within the mPFC across life, and suggest that such perturbations may contribute to the altered prefrontal structural and functional plasticity observed following early adversity.

Obesity and polycystic ovary syndrome: association with androgens, leptin and its genotypes.

Obesity and hyperandrogenaemia are key features of polycystic ovary syndrome (PCOS). The aim of this study was to investigate whether leptin and androgens are associated with obesity in PCOS subjects and identify whether there exist any genetic alterations in leptin gene in women with PCOS. The results reveal that leptin levels are elevated in women with PCOS and associate with BMI. However, irrespective of the obesity status leptin levels are higher in PCOS cases indicating that increased BMI/obesity may not be the only factor contributing to elevated levels of leptin. With regard to testosterone and androstenedione, the levels were increased in obese individuals irrespective of PCOS status. No correlation between leptin and androstenedione or testosterone was observed in controls and PCOS subjects. The single-nucleotide polymorphism G19A detected in the untranslated exon 1 of leptin gene was not associated with PCOS and does not contribute to elevated levels of leptin. The results overall suggest that androgen and leptin levels are increased in PCOS and obesity. It demonstrates that obesity is a confounding factor for hyperandrogenaemia irrespective of their PCOS status. The study rules out role of obesity status and leptin genotype in increase in leptin levels observed in PCOS cases.

CYP11A1 and CYP17 promoter polymorphisms associate with hyperandrogenemia in polycystic ovary syndrome.

OBJECTIVE: To analyze promoter regions of CYP11A1 and CYP17 for putative variations in a defined group of women with polycystic ovary syndrome (PCOS) and to study their association with androgen levels. DESIGN: Retrospective study. SETTING: A secondary referral center for infertility at National Institute for Research in Reproductive Health, Mumbai, India. PATIENT(S): One hundred women whose condition was diagnosed on the basis of the Rotterdam consensus were compared against 100 age-matched controls. INTERVENTION(S): A single sample of blood was collected after overnight fast on day 3 of the menstrual cycle. MAIN OUTCOME MEASURE(S): Plasma levels of T, androstenedione, 17alpha-hydroxyprogesterone, and DHEAS and nucleotide sequence of promoter regions of CYP11A1 and CYP17 genes. RESULT(S): Polymorphisms in promoter regions of the two key androgen-regulating genes, CYP11A1 and CYP17, were found to be significantly associated with T levels in the cohort of well-characterized PCOS cases as compared with controls. The significance was greater in the PCOS cases with both the polymorphisms. CONCLUSION(S): Our study carried out in a defined group of Indian women with PCOS suggests for the first time an individual, as well as combined, association of polymorphisms in CYP11A1 and CYP17 promoters with T levels.