Involvement of microRNAs in insulin resistance in the liver of non-obese type 2 diabetic rats undergoing bone marrow transplantation

• Grant number: 25/06630-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2025
• End date: February 28, 2027
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Sandro Massao Hirabara
• Grantee: Débora Aluiza Veríssimo
• Host Institution: Pró-Reitoria de Pós-Graduação e Pesquisa. Universidade Cruzeiro do Sul (UNICSUL). São Paulo , SP, Brazil

Abstract

Type 2 diabetes is a metabolic condition characterized by chronic hyperglycemia and impaired insulin sensitivity in responsive tissues to this hormone. According to International Health Organization, it is a worldwide worrying due to its high prevalence, mainly as a consequence of changes in lifestyle (diet and physical activity) and genetic factors. T2DM is commonly associated with obesity; however, a significant percentage of patients with T2DM does not present obesity; the mechanisms that lead to this condition is poorly understood. It is known that glucose metabolism in response to insulin is impaired in the liver of patients with T2DM and some studies suggest that microRNAs (miRs) may be involved in this process. In addition, some studies suggest that stem cell transplantation has a potential effect on reducing hyperinsulinemia and hyperglycemia, although the associated mechanisms are unknown in T2DM without obesity. The liver plays a crucial role in the whole energy metabolism, directly participating in processes involved in the release of glucose during prolonged fasting periods and in the storage of glucose in the form of glycogen, as well as in lipid metabolism through lipoproteins, further reinforcing its link with the pathogenesis of T2DM. Therefore, this project aims to evaluate the involvement of miRs in insulin resistance and glucose metabolism in the liver of Goto-Kakizaki (GK) rats, an animal model of T2DM without obesity, submitted or not to bone marrow transplantation from Wistar (WT) rats. Male WT and GK animals, aged 28 days, will be immunosuppressed with the drugs busulfan (20 mg/kg) and cyclophosphamide (150 mg/kg). After that, 2 x 107 bone marrow cells from WT donors (normoglycemic) will be injected via the caudal vein. Fasting blood glucose will be monitored on days 30, 60 and 90 after transplantation. On day 100, euthanasia will be performed and the liver wil be collected for future analyses of proteins (AKT-1/2, GSK3-¿, GLUT-2, FOXO-1, SREBP), enzymes (PFK-1, CS, GP and PEPCK) and cytokines (IL-6, IL-1¿ and TNF-¿; IL-10) that participate in glucose metabolism and hepatic insulin resistance, using the real-time PCR and Western Blotting. Also, it will be evaluated the miRs potentially related to the processes of insulin response, glucose metabolism and lipid metabolism (miR-143, miR-122, miR-26a, miR-195, miR-338-3p and miR-499-5p) by the real-time RT-PCR technique.