Paneth cells inhibit intestinal stem cell proliferation through the bone morphogenic protein 7 pathway under rotavirus-mediated intestinal injury.

BACKGROUND: Rotavirus (RV), a primary cause of diarrhea-related mortality in 2021, has been shown to damage intestinal epithelial cells while upregulating intestinal stem cells (ISCs) activities. ISCs within the crypt niche drive the continuous self-renewal of intestinal epithelium, preserving its barrier functions. Paneth cells secrete antimicrobial peptide and signaling molecules within the intestine crypt, thereby playing a crucial role in intestinal immune defense and providing ISCs functional support. However, the regulatory function of Paneth cells under pathological conditions, such as RV infection, remains unclear. AIM: To determine the impact of RV infection on Paneth cells and how Paneth cells regulate ISCs during intestinal injury repair. METHODS: We constructed a reference genome for the RV enteric cytopathogenic human orphan virus strain and reanalyzed published single-cell RNA sequencing data to investigate Paneth cell responses to RV-induced intestinal injury. We derived Paneth-ISC communication networks using CellChat, tracked ISC differentiation with pseudotime analysis, and validated our findings in leucine-rich repeat-containing G protein-coupled receptor 5-enhanced green fluorescent protein-internal ribosomal entry site-Cre recombinase estrogen receptor variant 2 mice and organoids via immunofluorescence, flow cytometry, and reverse transcription quantitative polymerase chain reaction. RESULTS: We found that RV directly infects Paneth cells, leading to a reduction in mature Paneth cells and an increase in kallikrein 1-high immature Paneth cells. Paneth-ISC communication was significantly enhanced. In particular, the bone morphogenic protein 7 (BMP7)-activin A receptor type 2B/BMP receptor type 1A-Smad pathway was upregulated post-infection, suggesting that Paneth cells suppress excessive ISC proliferation. Functional validation confirmed activation of this pathway. CONCLUSION: Paneth cells regulate ISC proliferation during RV infection by activating BMP7 signaling, limiting excessive stem cell expansion and preserving crypt homeostasis for effective epithelial repair.