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bioRxiv · 10.1101/2025.01.21.634180

Distinct Colitis-Associated Macrophages Drive NOD2-DependentBacterial Sensing and Gut Homeostasis

Katkar, G.·Anandachar, M. S.·Ibeawuchi, S.-R.·Espinoza, C.·Coates, J.·Malhotra, Y.·Mullick, M.·Castillo, V.·Vo, D. T.·Sahoo, D.·Sinha, S.·Ghosh, P.
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Abstract

Single-cell studies have revealed that intestinal macrophages maintain gut homeostasis through the balanced actions of reactive (inflammatory) and tolerant (non-inflammatory) subpopulations. How such balance is impaired in inflammatory bowel diseases (IBD), including Crohns disease (CD) and ulcerative colitis (UC), remains unresolved. Here, we define colon-specific macrophage states and reveal the critical role of non-inflammatory colon-associated macrophages (niColAMs) in IBD recovery. Through trans-scale analyses--integrating computational transcriptomics, proteomics, and in vivo interventional studies--we identified GIV (CCDC88A) as a key regulator of niColAMs. GIV emerged as the top-ranked gene in niColAMs that physically and functionally interacts with NOD2, an innate immune sensor implicated in CD and UC. Myeloid-specific GIV depletion exacerbates infectious colitis, prolongs disease, and abolishes the protective effects of the NOD2 ligand, muramyl dipeptide, in colitis and sepsis models. Mechanistically, GIVs C-terminus binds the terminal leucine-rich repeat (LRR#10) of NOD2 and is required for NOD2 to dampen inflammation and clear microbes. The CD-associated 1007fs NOD2-variant, which lacks LRR#10, cannot bind GIV--providing critical insights into how this clinically relevant variant impairs microbial sensing and clearance. These findings illuminate a critical GIV-NOD2 axis essential for gut homeostasis and highlight its disruption as a driver of dysbiosis and inflammation in IBD.

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Katkar, G., Anandachar, M. S., Ibeawuchi, S.-R., Espinoza, C., Coates, J., Malhotra, Y., Mullick, M., Castillo, V., Vo, D. T., Sahoo, D., Sinha, S., Ghosh, P.. 2025-01-24. Distinct Colitis-Associated Macrophages Drive NOD2-DependentBacterial Sensing and Gut Homeostasis. https://doi.org/10.1101/2025.01.21.634180

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