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.
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