Muribaculum intestinale negatively impacts glioma growth through the toll-like receptor 2 in mice

Recent studies have demonstrated a link between the composition of the gut microbiota and gliomaprogression. Here, we describe that the growth of glioma in mice is inversely correlated with therelative abundance of the anaerobic bacterium Muribaculum intestinale in the feces. We found thatM. intestinale administration: 1) induced an inflammatory environment in the gut; 2) reducedglioma growth; 3) increased the pro-inflammatory profile of tumor-associated microglial cells andthe frequency of CD8+ T cells; and 3) increased the peripheral TNF-alfa levels. The effects inducedby M. intestinale administration were significantly reduced upon toll-like receptor 2 (TLR2)silencing with siRNA-loaded dendrimers. Collectively, these data demonstrate that M.intestinale induces a pro-inflammatory response in glioma bearing mice, inhibiting tumor growthwith a TLR2-dependent signaling.