How does sex and estrogen impact the O-GlcNAc pathway? A proteomic approach

• Grant number: 19/26374-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: March 01, 2021
• End date: February 28, 2022
• Field of knowledge: Biological Sciences - Pharmacology - Cardiorenal Pharmacology
• Principal Investigator: Rita de Cassia Aleixo Tostes Passaglia
• Grantee: Tiago Januário da Costa
• Supervisor: Natasha Elizabeth Zachara
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: Johns Hopkins University (JHU), United States
• Associated to the scholarship: 17/25116-2 - Role of O-GlcNacylation (O-GlcNAc) on the expression and function of classical estrogen receptor alpha (ERa66kDa) and splice variant of estrogen receptor alpha (ERa36kDa) in the common carotid artery of aging mice, BP.PD

Abstract

Premenopausal women are considered hemodynamically younger than men, but this difference is abolished in post-menopause. The postmenopausal period is associated with reduced plasma estrogen levels. Currently, estrogen therapy effects are controversial because estrogen has a dual effect in the vasculature. Whereas estrogen has a protective effect in premenopausal women/females, by increasing the synthesis of nitric oxide (NO) and prostacyclin (PGI2) in endothelial cells e.g., the beneficial vascular effects of estrogen therapy are abrogated and are associated with increased cardiovascular risk in aged females. Similarly, activation of the O-GlcNAc pathway, a post-translational modification that controls the function of many proteins, has dual effects in the cardiovascular system. On one hand, increased O-GlcNAc levels are beneficial in conditions associated with cell injury, including oxidative stress, hypoxia, ischemia and reperfusion, and trauma hemorrhage, conferring a protective response. On the other hand, in chronic conditions, such as arterial hypertension, diabetes, and ageing, elevated levels of O-GlcNAc-modified proteins have been associated with vascular dysfunction. Changes in O-GlcNAc levels alter the behavior and fate of proteins by modulating enzyme activity, protein-protein interactions, DNA binding, subcellular localization and degradation. Important vascular proteins, such as endothelial nitric oxide synthase (eNOS), are modified by O-GlcNAc. Increased O-GlcNAc modification of eNOS decreases the enzyme activity and has an important impact on vascular function, indicating that the O-GlcNAc pathway may contribute to vascular abnormalities in disease and non-disease states. Since little is known on the effects of estrogen and sex in O-GlcNAc signaling in vascular cells and how increased O-GlcNAc levels impact vascular function in ageing and cardiovascular diseases, the aim of this study is to investigate whether estrogen and sex alter O-GlcNAc signaling in endothelial cells and how increased O-GlcNAc levels affect signaling pathways in endothelial cells. In this project, we will test the hypothesis that sex and estrogen modify the O-GlcNAc signaling pathway in EC, which may contribute to the modulation of expression and activity of key vascular proteins. Therefore, will evaluate how estrogen modifies the expression and activity of key proteins of the O-GlcNAc pathway, including OGT, OGA, GFAT, as well as O-GlcNAc-targeted proteins (Aim 1). To gain insight into the proteins and pathways regulated by O-GlcNAc in cells experiencing estrogen, we will seek to define the differential O-GlcNAc sub-proteome of EC treated with estrogen (Aim 2). Experimental protocols to address our specific aims will be performed in the laboratory of Prof. Natasha E. Zachara at the Johns Hopkins Medical School. Prof. Zachara is a world leader in Glycobiology and has made seminal contributions to the O-GlcNAc field.This study complements Dr. Tiago's project in Brazil, where he investigates the Role of O-GlcNAcylation (O-GlcNAc) on the expression and function of classical estrogen receptor alpha (ERa66kDa) in the common carotid artery of aged mice. (AU)