Scientists found that a brain peptide called cortistatin can calm down a type of immune cell (Th17) that drives inflammation. It does this by slowing down the cell's sugar‑burning (glycolysis) through a pathway involving the proteins Myc and HK2, and it needs the growth‑hormone secretagogue receptor (GHSR1) to work. In a mouse model of gut inflammation, giving cortistatin reduced the harmful Th17 response, but blocking GHSR1 stopped this benefit.

The neuropeptide cortistatin (CST) has been reported to attenuate Th17 cell response in multiple disease models, but the mechanism of action remains obscure. Here, we show that either overexpression or exogenous addition of CST obviously restricts Th17 cell differentiation. As metabolic reprogramming plays an important role in Th17 cell development, we explore whether CST inhibits Th17 cell differentiation by regulating glycolysis. The results show that CST substantially attenuates the glycolysis during Th17 differentiation and down-regulates the mRNA expression of myelocytomatosis oncogene (Myc) and hexokinase 2 (HK2), the glycolysis rate-limiting enzyme. Following the overexpression of Myc and HK2, the inhibitory effect of CST on Th17 differentiation nearly disappears, suggesting that Myc-HK2 pathway is deeply involved. Furthermore, growth hormone secretagogue receptor 1 (GHSR1) is identified as the key receptor subtype for CST attenuating glycolysis and Th17 cell differentiation by the combined uses of CST with various receptor subtype blockers. The knockdown of GHSR1 abrogates the inhibition of CST on Th17 differentiation and glycolysis. Finally, in the colitis mice induced by dextran sulfate sodium, an intraperitoneal injection of CST markedly inhibits Th17 cell response and down-regulates the expression of HK2 in the Th17 cells, which is reversed by the combined use of GHSR1 antagonist. These findings suggest that inhibition of glycolysis is the key pathway for CST attenuating Th17 cell response, and GHSR1, Myc and HK2 are potential therapeutic targets of Th17 cell-related diseases.