Francisco J. Quintana, which we had the plasure to listen in the last AINI congress in Trieste, published this astounding paper on Nature on the role played by the metabolites produced by the commensal flora on microglial cells, and the way they respectively control inflammation by modulating astrocyte functions.
The authors demonstrated that microglial cells control atrocytes activation through the production of two main cytokines, TGF-alpha and VEGF-B, that operate by respectively limiting and activating their pathogenetic and inflammatory signals. This feature is controlled, on microglia, by the aryl hydrocarbon receptor (AHR): upon engaging endogenous bacterial metabolites, AHR promotes TGF-alpha production while inhibiting the release of VEGF-B. Of note, AHR deletion in EAE mice worsened the clinical phenotype, suggesting that this immunoregulatory pathway might be important in multiple sclerosis pathogenesis, as well as strengthening the idea that gut microbiota plays an important role in peripheral and central inflammation and in MS pathogenesis.
Original paper (only for registered users).
Cover Image modified from Immy Smith Art