IL-27, a metabolic regulator secreted by astrocytes in response to GLP-1RA OHP2, modulates microglial reprogramming in Alzheimer's disease by regulating cGAS lactylation.

Microglia-mediated neuroinflammation, considered one of the most plausible pathogenic hypotheses underlying Alzheimer’s disease (AD), plays a pivotal role in the initiation and progression of this devastating condition. Recently, glucagon-like peptide-1 receptor agonists (GLP-1RAs) have demonstrated promising neuroprotective effects in both preclinical and clinical studies. Previously, we developed an orally-administered GLP-1RA peptide called OHP2, which is capable of crossing the blood-brain barrier for the treatment of AD. OHP2 has been shown to effectively reduce brain inflammation in AD mouse models. In this study, we discovered that OHP2 treatment induced IL-27 secretion from astrocytes and modulated microglial reprogramming from the neurotoxic M1 phenotype to the neuroprotective M2 phenotype through glycolysis/cGAS lactylation clock/mTOR pathway, thereby alleviating excessive neuroinflammation. These findings provide a rationale for further pharmacological investigations into OHP2 and suggest that IL-27 may hold significant implications for AD therapy as a metabolic regulator.