Immunometabolism of lymphocytes and its changes in experimental diabetes mellitus

Abstract

Lymphocytes are sensitive to changes in metabolism. Metabolic changes, which develop in conditions of diabetes mellitus, especially hyperglycemia, can directly influence the immunometabolism of lymphocytes. The T cells express a series of glucose transporters, the main of which is the Glut 1. The prodiabetogenic Th1 and Th17-cells that cause insulitis are characterized by high level of expression of Glut 1 and tendency to glycolysis. The suppressor Treg, on the contrary, has the low expression of Glut 1 and the high rate of oxidative metabolism. Purpose of the study: to analyze the contemporary literature and own data, obtained concerning the immunometabolism of lymphocyte and its changes in conditions of diabetes. To determine the role of 6 key metabolic ways that play a crucial role in the differentiation and survival of immune cells: 1) glycolysis; 2) tricarboxylic acid (TCA) cycle; 3) pentose-phosphate cycle; 4) fatty acid oxidation; 5) fatty acid synthesis and 6) metabolism of amino acids, each of which have different activity level in specific types of immune cells. Conclusions: different types of immune cells prefer different ways of metabolism. The effector Th1-, Th2-, Th17-cells and М1-macrophages use primarily glycolysis, pentose-phosphate cycle and synthesis of fatty acids, while T-regulatory, CD8 + memory cells and M2-macrophages use the TCA cycle and oxidation of fatty acids. Changes in the metabolism of different amino acids can influence the generation of effector and Treg lymphocytes. The high activity of mTOR can enhance the progression of diabetes by activating the effector proinflammatory subpopulations of lymphocytes, and vice versa, the low activity promotes the differentiation of Treg, blocking the insulitis. In our work we investigated the level of expression of mRNA of genes Glut 1, mTOR and AMPK1α in PLN of rats with experimental streptozotocin-induced diabetes and after metformin introduction and found that the hyperglycemia caused the transcription induction of the gene of glucose transporters Glut 1 in PLN cells. The increase of the level of mRNA genes of glucose transporters Glut 1 and protein kinase mTOR in immune cells in diabetes, which we determined, is an important trigger of their differentiation into effector proinflammatory Th1 and Th17 subpopulations.