Integrated mitochondrial stress response and the regulation of pro-opiomelanocortin processing in hypothalamic neuronal cell lines

• Grant number: 21/06461-6
• Support Opportunities: Scholarships in Brazil - Master
• Start date: May 01, 2022
• End date: July 31, 2023
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Licio Augusto Velloso
• Grantee: Lara Regina Ferreira
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 13/07607-8 - OCRC - Obesity and Comorbidities Research Center, AP.CEPID

Abstract

Saturated fatty acids, such as palmitate, are important components of the diet that induce functional and structural disorders of anorexigenic neurons hypothalamic POMC, initially generating defects in the regulation of enzymes that process proopiomelanocortin and later lead to inflammation hypothalamic. It has been recently shown that cellular stress caused by CRF1 deletion leads to activation of the mitochondrial response of misfolded proteins (UPRmt, mitochondrial unfolded protein response) promoting alteration of the enzymatic processing of POMC and predisposing to the development of obesity. However, it has not been fully elucidated whether UPRmt affects peptidases that process POMC. In this study, we will use hypothalamic neuron strains expressing POMC to assess whether palmitate-induced cellular stress is capable of affecting POMC processing through UPRmt and anomalous regulation of PC1/3 and PC2 enzymes. The strains will be exposed to a concentration of palmitate able to induce changes in the expression of peptidases and UPRmt will be evaluated by measuring the expression of markers of the phenomenon, as well as by functional assays of mitochondrial respiration. In a second step, communication between UPRmt and regulation of gene expression in the nucleus will be interrupted through inhibition of the CRIF1/MOTS-c system using a siRNA against CRIF1. The impact of disruption of communication between mitochondria and nucleus on POMC processing will be evaluated by measuring PC1/3, PC2, and by-products a-MSH and b-endorphins. We believe that elucidating the mechanisms by which acids saturated fatty acids present in the diet affect the function of POMC neurons as well as changes in CRIF1, will contribute to advances in the characterization of pathophysiology neural of obesity.