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Molecular mechanisms of the ARHGAP21 RhoGAP in the VLDL vesicles formation in hepatocytes of ARHGAP21-heterozygous C57BL/6 mice

Grant number: 15/23729-1
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): February 01, 2016
Effective date (End): August 02, 2018
Field of knowledge:Biological Sciences - Physiology - Physiology of Organs and Systems
Principal Investigator:Helena Cristina de Lima Barbosa Sampaio
Grantee:Lucas Zangerolamo
Home Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
Associated research grant:15/12611-0 - Molecular mechanisms involved in pancreatic beta cell disfunction and dead in diabetes mellitus: strategies for the inhibition of these processes and restoration of the insular mass, AP.TEM

Abstract

ARHGAP21 controls multiple cellular functions, such as migration, proliferation, differentiation and vesicles intracellular traffic. ARHGAP21 is a molecular partner of ARFs GTPases, controlling the formation of vesicles from the Golgi. Our ARHGAP21-heterozygous animal model (Het, 50% of the protein expression) treated with the high fat diet (HFD) had higher content of triglycerides in the liver, compared to C57BL/6 animals fed on the same diet. The HFD favored the accumulation of lipids in the Het animal, however, we do not know how the reduced content of ARHGAP21 in vivo stimulated greater hepatic steatosis in this animal. Thus, there is a possibility that ARHGAP21 is involved in the mechanisms associated with lipogenesis or liver lipids secretion. In this work, using C57BL/6 mice that are heterozygous for the ARHGAP21 and fed the high fat diet, we will evaluate gene and protein content of lipogenesis-involved proteins by q-PCR and Western blotting, respectively; lipid accumulation using colorimetric-enzymatic method and oil red; interaction between ARFs and ARHGAP21 by immunoprecipitation assay as well as co-localization by immunofluorescence and confocal microscopy; apoptosis will be assessed by flow cytometry; and insulin signaling will be measured by phosphorylation of AKT in serine residue. The groups will be analyzed by two-way ANOVA followed by Bonferroni post-test to assess significance of the results. Considering the substantial involvement of the liver in the dyslipidemia associated with nutritional overload, this project aims to investigate the possible involvement of ARHGAP21 in the formation of VLDL vesicles in hepatocytes from normal and Het C57BL/6 mice subjected to a HFD. This project will bring contributions on the understanding of the molecular mechanisms that lead to accumulation of liver lipids, as well as potential elucidation of ARHGAP21 signaling pathways.

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
ZANGEROLAMO, LUCAS; SOARES, GABRIELA MOREIRA; VETTORAZZI, JEAN FRANCIESCO; DO AMARAL, MARIA ESMERIA; CARNEIRO, EVERARDO MAGALHAES; OLALLA-SAAD, SARA TERESINHA; BOSCHERO, ANTONIO CARLOS; BARBOSA-SAMPAIO, HELENA CRISTINA. ARHGAP21 deficiency impairs hepatic lipid metabolism and improves insulin signaling in lean and obese mice. Canadian Journal of Physiology and Pharmacology, v. 97, n. 11, p. 1018-1027, NOV 2019. Web of Science Citations: 0.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.