Abstract P366: The Impact Of Estrogen Signaling On Gut Epithelial Cells

Abstract

Cardiovascular disease (CVD) is the leading cause of death in women worldwide. Menopause is associated with increased susceptibility to CVD, but the mechanism is currently unknown. Studies have suggested that loss of estrogen signaling in the intestine during menopause may lead to worse myocardial infarction (MI) outcomes in female mice. Our lab has shown that suppressing inflammation in the gut using pre- and pro-biotics protects the heart from ischemic heart disease caused by MI through unknown means. We propose that alterations in gut microbiota are due to destruction of intestinal pattern recognition receptors (PRRs) such as toll-like receptor 4 (TLR4) and TLR5. Studies show that estrogen signaling modulates PRRs in other tissues, but this has yet to be investigated in gut epithelial cells. To elucidate the mechanisms of estrogen receptor function in the gut as a direct mediator of vascular health, we are utilizing an immortalized human cell line of colorectal adenocarcinoma brush border expressing (Caco2 BBE) cells. We hypothesized that estrogen treatment in gut epithelial cells will lead to increased expression of PRRs and decreased inflammation in Caco2 BBE cell lines. To investigate expression and localization of estrogen receptors (ERs), Caco2 BBE cells at different confluency were treated with estradiol (E2) or DMSO control for 24hrs, then either RNA or protein were harvested for use in qPCR and western blot, or cells were formalin fixed for use in immunohistochemistry. In each case, ERα was not detected, but ERβ was present at varying concentrations. Data also showed increased expression of TLR5 and TLR7 in E2 treated cells, while TNF-α and IL-1 were decreased. In conclusion, data show potential confluency dependent ERβ expression and suggest that ERα may not be present in our Caco2 BBE cell line. Our hypothesis is also supported by data for PPRs and inflammatory markers. Though these results are revealing, future studies are needed to further characterize Caco2 BBE cells in the context of ER signaling.