The impact of deletion of the Nr1d1 gene in the skeletal muscle of obese mice

• Grant number: 23/15884-3
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: September 01, 2024
• End date: August 31, 2029
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Adelino Sanchez Ramos da Silva
• Grantee: Danielle Naves Ribeiro
• Host Institution: Escola de Educação Física e Esporte de Ribeirão Preto (EEFERP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 19/11820-5 - Nr1d1 function on the aging-associated Sarcopenia, AP.TEM

Abstract

The alteration of circadian rhythms has been identified as a key risk factor for developing obesity and type 2 diabetes. The nuclear receptor Nr1d1 (Rev-erb±) is a central component of the circadian cycle and has been highlighted as an essential link between the circadian cycle and metabolism. It has been observed that the Rev-erb± protein meticulously controls the autophagy pathway, which is directly related to obesity. Given that genes involved in the circadian rhythm play a significant role in regulating energy balance in mammals, the disruption of these genes may contribute to the development of obesity and metabolic syndrome in mice. Therefore, understanding the function of the Nr1d1 (Rev-erb±) gene in skeletal muscle and the molecular pathways that this protein can modulate in the condition of obesity is crucial for advancing knowledge about the function of this protein. Thus, the primary objective of this study is to determine whether obese animals, induced by a high-fat diet, lacking the Nr1d1 gene in skeletal muscle, would exhibit an exacerbation of obesity pathogenesis in muscle health (muscle composition and size, performance, adiposity, inflammation, etc.), as well as the autophagy response in this scenario, compared to their control peers. Homozygous flox mice of the Nr1d1 gene and conditional knockout (KO) mice (skeletal muscle) of the Nr1d1 gene with both control and high-fat diets (HFD), as well as animals that will be transfected with the adeno-associated virus for overexpression of Rev-erb±, will be used. The animals will undergo metabolic testing and physical performance assessments before and after eight weeks of a high-fat diet to verify the interference of the diet and genetic model on physical and metabolic parameters. After the tests, blood and skeletal muscle (soleus, extensor digitorum longus - EDL, and tibialis anterior - TA) will be removed and stored at -80°C for biochemical analyses, quantitative reverse transcription polymerase chain reaction (RT-qPCR), immunoblotting, stereological analyses, electron paramagnetic resonance (EPR), proteomics, and bioinformatics. The results will be expressed as mean ± standard deviation. All analyses will be bilateral, and the significance level will be pd0.05. (AU)