4-Hydroxyisoleucine Alleviates Macrophage-Related Chronic Inflammation and Metabolic Syndrome in Mice Fed a High-Fat Diet

In obesity, macrophages and other immune cells accumulate in organs affected by Insulin, leading to chronic inflammation and Insulin resistance. 4-Hydroxyisoleucine (4-HIL) is a non-protein amino acid found in fenugreek seeds. 4-HIL enhances Insulin sensitivity, but its mechanism is still unclear. In this study, 4-HIL intervention reduced weight gain, liver steatosis, and dyslipidemia; moreover, it increased systemic Insulin sensitivity and improved Insulin resistance in mice. Importantly, after administration, the accumulation of M1 like CD11c⁺ macrophages and inflammation in the liver and adipose tissue were reduced in the mice. 4-HIL also reduced the proportion of CD11c⁺ macrophages among bone marrow-derived macrophages, which were induced in vitro. These observations demonstrate a new role of 4-HIL in Insulin resistance in hepatocytes and adipocytes. 4-HIL inhibits obesity-related Insulin resistance by reducing inflammation and regulating the state of M1/M2 macrophages.

4-hydroxyisoleucine; inflammation; insulin resistance; macrophages; obesity.