Project description:<p>The HTN-IR Study, funded by NHLBI, was designed to explore genetic contributions to hypertension and glucose homeostasis traits among Hispanics using a family-based design. The baseline examination of the cohort included the euglycemic hyperinsulinemic clamp test from which the two key phenotypes were obtained: insulin sensitivity (M) and metabolic clearance rate of insulin (MCRI). Genome-wide genotyping was obtained under separate funding by NIDDK as a part of the GUARDIAN (Genetics Underlying Diabetes in Hispanics) Consortium. </p>
Project description:To explore genes that could be responsible to insulin in insulin resistance states (IR), we generated the IR mice models (mice after 6 weeks of high-fat feeding).
Project description:Insulin resistance is accompanied by chronic hyperinsulinemia and is associated with type 2 diabetes and other metabolic syndromes in a substantial portion of the population. The risk factors and features of insulin resistance have been thoroughly described but its mechanistic triggers are still under study. Here we consider a condensate model for insulin receptor (IR) function in normal conditions and when dysregulated in chronic hyperinsulinemia-induced insulin resistance. We find that IR is incorporated into liquid-like condensates at the plasma membrane, in the cytoplasm and in the nucleus of liver cells, and provide evidence for insulin-dependent IR function in condensates. Insulin stimulation promotes further incorporation of IR into these dynamic condensates in insulin sensitive cells, which form and dissolve on short, sub-minute time-scales. In contrast, insulin stimulation does not promote further incorporation of IR into condensates in insulin resistant cells, where IR molecules within condensates exhibit less dynamic behavior. Metformin treatment of insulin resistant cells rescues IR condensate dynamics and insulin responsiveness. Insulin resistant cells experience high levels of oxidative stress, which causes reduced condensate dynamics, and treatment of these cells with metformin reduces ROS levels and returns condensates to their normal dynamic behavior. The condensate model we propose can account for features of normal and dysregulated insulin response and has implications for improved therapeutic approaches to insulin resistance.
