Sex-Determining Region Y Controls the Effects of Fetal Alcohol Exposure on Proopiomelanocortin Gene Expression.

Omkaram Gangisetty,Edward A Mead,Dipak K Sarkar

doi:10.3389/fnins.2021.608102

Omkaram Gangisetty, Edward A Mead + Show 1 more

Open Access

https://doi.org/10.3389/fnins.2021.608102

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Abstract

Fetal alcohol exposure (FAE) causes various neurodevelopmental deficits in offspring, including reduced expression of the stress regulatory proopiomelanocortin (Pomc) gene and an elevated stress response for multiple generations via the male germline. Male germline-specific effects of FAE on the Pomc gene raises the question if the sex-determining region Y (SRY) may have a role in regulating Pomc gene expression. Using a transgenerational model of FAE in Fischer 344 rats, we determined the role of SRY in the regulation of the Pomc gene. FAEs, like on the Pomc gene, reduced Sry gene expression in sperm and the mediobasal hypothalamus (MBH) in male adult offspring. Fetal alcohol-induced inhibition of Sry gene expression was associated with increased Sry promoter DNA methylation. Additionally, fetal alcohol effects on the Sry gene persisted for three generations in the male germline but not in the female germline. Sry gene knockdown reduced the Pomc gene expression. Sry recruitment onto the Pomc promoter was found to be reduced in the hypothalamus of fetal alcohol-exposed rats compared to control rats. Pomc promoter luciferase activity was increased following Sry overexpression. A site-directed mutagenesis study revealed that SRY binding sites are required for POMC promoter transcription activity. Overall, these findings suggest that SRY plays a stimulatory role in the regulation of Pomc gene expression and may potentially contribute to the fetal alcohol-induced changes in the level of Pomc gene expression for multiple generations.

Highlights

Fetal alcohol exposure (FAE) has been shown to elevate neuroendocrine response of the hypothalamic-pituitary-adrenal (HPA) axis to stress (Ogilvie and Rivier, 1997; Hellemans et al, 2010; Bakoyiannis et al, 2014; Sarkar et al, 2019), partly due to a lack of the inhibitory control of the proopiomelanocortin (POMC)-derived peptide in the hypothalamus (Sarkar et al, 2007; Wynne and Sarkar, 2013)
We used a liquid diet model of alcohol feeding in pregnant rats between day 7 and 21 of pregnancy that is known to raise blood levels of alcohol in the range of 120–150 mg/dl (Miller, 1992) and produce offspring with endophenotypes similar to those found in human fetal alcohol spectrum disorders
We show that FAE increases Sry DNA methylation and suppresses Sry gene expression in the mediobasal hypothalamus (MBH) and in sperm of Fischer 344 rats (Figures 1C,D,G,H)

Summary

INTRODUCTION

Fetal alcohol exposure (FAE) has been shown to elevate neuroendocrine response of the hypothalamic-pituitary-adrenal (HPA) axis to stress (Ogilvie and Rivier, 1997; Hellemans et al, 2010; Bakoyiannis et al, 2014; Sarkar et al, 2019), partly due to a lack of the inhibitory control of the proopiomelanocortin (POMC)-derived peptide in the hypothalamus (Sarkar et al, 2007; Wynne and Sarkar, 2013). SRY Regulation of POMC Gene rats (Boyadjieva et al, 2009), suggesting that FAE suppresses the level of POMC to alter the function of the HPA axis. FAEinduced changes in Pomc promoter DNA methylation bypasses epigenetic reprogramming during embryonic development and are transmitted for multiple generations only through the male— but not female germline (Govorko et al, 2012; Sarkar, 2016), suggesting the possibility of involvement of a male-specific chromosome/gene which overcomes developmental editing and regulates Pomc gene expression. The sex-determining region Y (SRY) is one of the functional genes involved in male reproduction that is mapped on YNPAR. We determined FAE effects on Pomc and Sry expression in the mediobasal hypothalamus (MBH) and sperm.

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ETHICS STATEMENT