Intercrypt sentinel macrophages tune antibacterial NF-κB responses in gut epithelial cells via TNF.

Hausmann A, Felmy B, Kunz L, Kroon S, Berthold DL, Ganz G, Sandu I, Nakamura T, Zangger NS, Zhang Y, Dolowschiak T, Fattinger SA, Furter M, Müller-Hauser AA, Barthel M, Vlantis K, Wachsmuth L, Kisielow J, Tortola L, Heide D, Heikenwälder M, Oxenius A, Kopf M, Schroeder T, Pasparakis M, Sellin ME, Hardt WD

J. Exp. Med. 218 (11) - [2021-11-01; online 2021-09-16]

Intestinal epithelial cell (IEC) NF-κB signaling regulates the balance between mucosal homeostasis and inflammation. It is not fully understood which signals tune this balance and how bacterial exposure elicits the process. Pure LPS induces epithelial NF-κB activation in vivo. However, we found that in mice, IECs do not respond directly to LPS. Instead, tissue-resident lamina propria intercrypt macrophages sense LPS via TLR4 and rapidly secrete TNF to elicit epithelial NF-κB signaling in their immediate neighborhood. This response pattern is relevant also during oral enteropathogen infection. The macrophage-TNF-IEC axis avoids responses to luminal microbiota LPS but enables crypt- or tissue-scale epithelial NF-κB responses in proportion to the microbial threat. Thereby, intercrypt macrophages fulfill important sentinel functions as first responders to Gram-negative microbes breaching the epithelial barrier. The tunability of this crypt response allows the induction of defense mechanisms at an appropriate scale according to the localization and intensity of microbial triggers.

Mikael Sellin

SciLifeLab Fellow

PubMed 34529751

DOI 10.1084/jem.20210862

Crossref 10.1084/jem.20210862

pii: 212646
pmc: PMC8480669

Publications 9.5.0