Transcriptomic signatures of menopause across human tissues

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PROJECT SUMMARY Unfortunately, women have increased coronary heart disease, stroke, and mortality risk after menopause. This can be partially attributed to increases in cardiovascular disease (CVD) risk factors that many women experience after menopause, such as blood pressure, lipid levels, and adiposity, but the mechanisms behind these and other changes are poorly understood. A reduction in circulating estrogen levels is one of the major changes with menopause, and estrogen can transcriptionally regulate many genes, often in a tissue-specific manner. Prior studies of changes in gene expression with menopause have been limited, and most have been focused on breast, bone, and female reproductive tissues. We hypothesize that transcriptomic examination of cardiometabolic tissues across the menopause transition will reveal insight into the molecular processes responsible for the increased CVD risk. Though menopause status information is missing from most human tissue gene expression datasets, we hypothesize that menopausal status can be inferred from gene expression data. To accomplish this, in Aim 1A we will infer the menopausal status of hundreds of female Genotype-Tisssue Expression (GTEx) subjects based on the gene expression profiles of their female reproductive tissues, using a combination of dimensionality reduction approaches informed by known biology and more agnostic, clustering- based methodology. Since the average GTEx subject contributed samples from over 18 tissues, we will have inferred menopausal status information for non-reproductive tissues as well. In a preliminary analysis of uterus gene expression data (withholding age as a covariate), we observed clear classification of individuals into an inferred premenopausal and an inferred postmenopausal group. In Aim 1B, we will use the inferred menopausal status information from Aim 1A to identify genes and pathways that are differentially expressed in tissues derived from inferred premenopausal versus postmenopausal women, focusing on cardiometabolic tissues of relevance to cardiovascular disease, such as liver, adipose, and blood vessels. Finally, since menopause status is confounded by age, in Aim 2 we will identify sex-specific aging genes in cardiometabolic GTEx tissues and other existing human tissue gene expression datasets with age and sex information from suitable numbers of younger (age<50) and older (age >50) adults and examine the relationship of gene expression with chronological age in each sex subset. Inferred menopause-related genes that do not exhibit similar correlations with chronological age in male tissues are likely to be regulated by the female-specific hormonal changes during menopause rather than more general aging processes. Overall, this will be the most comprehensive evaluation of the effects of menopause on gene expression performed to date, and the findings could identify molecular pathways underlying the increased disease burden in post-menopausal women.