New insights into inflammation and insulin resistance in muscle cells
A study by the research team led by Prof. Kai Kappert, published in Cellular Signalling, investigates the role of pro-inflammatory cytokines in the regulation of protein tyrosine phosphatases (PTPs) and insulin signaling pathways in murine skeletal muscle cells (C2C12). The research shows how tumor necrosis factor (TNF), interleukin-1? (IL-1?), and interleukin-6 (IL-6) influence the expression and activity of PTPN1 (PTP1B) and PTPN2 (TCTP), which are considered negative regulators of the insulin signaling pathway. The study demonstrates that the cytokines induce different kinetics and expression patterns of PTPs and insulin signaling molecules without significantly impairing insulin action. Pharmacological inhibition with sodium orthovanadate and siRNA-mediated knockdown of PTPN1 and PTPN2 confirmed that PTPs inhibit insulin signal transduction. However, the knockdown showed only minor effects on the insulin signaling pathway, as other PTPs were regulated compensatorily. The results highlight the complex interplay between cytokines, PTPs, and metabolic signaling pathways. These findings are crucial for the development of new therapeutic approaches for inflammatory diseases such as type 2 diabetes…

