Commensal bacteria weaken the intestinal barrier by suppressing epithelial neuropilin-1 and Hedgehog signaling.


Giulia Pontarollo, Bettina Kollar, Amrit Mann, My Phung Khuu, Klytaimnistra Kiouptsi, Franziska Bayer, Inês Brandão, Valeriya V Zinina, Jennifer Hahlbrock, Frano Malinarich, Maximilian Mimmler, Sudhanshu Bhushan, Federico Marini, Wolfram Ruf, Meriem Belheouane, John F Baines, Kristina Endres, Scott M Reba, Verena K Raker, Carsten Deppermann, Christoph Welsch, Markus Bosmann, Natalia Soshnikova, Benoit Chassaing, Mattias Bergentall, Felix Sommer, Fredrik Bäckhed, Christoph Reinhardt

Year of publication



Nat Metab







Impact factor



The gut microbiota influences intestinal barrier integrity through mechanisms that are incompletely understood. Here we show that the commensal microbiota weakens the intestinal barrier by suppressing epithelial neuropilin-1 (NRP1) and Hedgehog (Hh) signaling. Microbial colonization of germ-free mice dampens signaling of the intestinal Hh pathway through epithelial Toll-like receptor (TLR)-2, resulting in decreased epithelial NRP1 protein levels. Following activation via TLR2/TLR6, epithelial NRP1, a positive-feedback regulator of Hh signaling, is lysosomally degraded. Conversely, elevated epithelial NRP1 levels in germ-free mice are associated with a strengthened gut barrier. Functionally, intestinal epithelial cell-specific Nrp1 deficiency (Nrp1ΔIEC) results in decreased Hh pathway activity and a weakened gut barrier. In addition, Nrp1ΔIEC mice have a reduced density of capillary networks in their small intestinal villus structures. Collectively, our results reveal a role for the commensal microbiota and epithelial NRP1 signaling in the regulation of intestinal barrier function through postnatal control of Hh signaling.