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Multimodal Single-cell Analyses Reveal Mechanisms of Perianal Fistula in Diverse Patients with Crohn's Disease

Abstract

Background: Crohn's disease complicated by perianal fistulae is more prevalent and severe in patients of African ancestry.

Methods: We profiled single cells from diverse patients with Crohn's disease with perianal fistula from colorectal mucosa and fistulous tracts. Immunofluorescence was performed to validate predicted cell-cell interactions. Unstimulated monocytes were chronically cultured in diverse cohorts. A subset was analyzed by single-nucleus RNA + ATAC sequencing.

Findings: Fistulous tract cells from complete proctectomies demonstrated enrichment of myeloid cells compared to paired rectal tissues. Ligand-receptor analysis highlights myeloid-stromal cross-talk and cellular senescence, with cellular co-localization validated by immunofluorescence. Chitinase-3 like-protein-1 (CHI3L1) is a top upregulated gene in stromal cells from fistulae expressing both destructive and fibrotic gene signatures. Monocyte cultures from patients of African ancestry and controls demonstrated differences in CHI3L1 and oncostatin M (OSM) expression upon differentiation compared to individuals of European ancestry. Activating protein-1 footprints are present in ATAC-seq peaks in stress response genes, including CHI3L1 and OSM; genome-wide chromatin accessibility including JUN footprints was observed, consistent with reported mechanisms of inflammatory memory. Regulon analyses confirm known cell-specific transcription factor regulation and implicate novel ones in fibroblast subsets. All pseudo-bulked clusters demonstrate enrichment of genetic loci, establishing multicellular contributions. In the most significant African American Crohn's genetic locus, upstream of prostaglandin E receptor 4, lymphoid-predominant ATAC-seq peaks were observed, with predicted RORC footprints.

Conclusions: Population differences in myeloid-stromal cross-talk implicate fibrotic and destructive fibroblasts, senescence, epigenetic memory, and cell-specific enhancers in perianal fistula pathogenesis. The transcriptomic and epigenetic data provided here may guide optimization of promising mesenchymal stem cell therapies for perianal fistula.

Funding: This work was supported by grants U01DK062422, U24DK062429, and R01DK123758.

Citing Articles

Single-Cell and Spatial Multi-omics Reveal Interferon Signaling in the Pathogenesis of Perianal Fistulizing Crohn's Disease.

Cao S, Nguyen K, Ma K, Yao X, Liu T, Ayoub M bioRxiv. 2024; .

PMID: 39574705 PMC: 11581043. DOI: 10.1101/2024.11.08.620717.


Single-cell transcriptomics of rectal organoids from individuals with perianal fistulizing Crohn's disease reveals patient-specific signatures.

Murthy S, Anbazhagan M, Maddipatla S, Kolachala V, Dodd A, Pelia R Sci Rep. 2024; 14(1):26142.

PMID: 39477985 PMC: 11526126. DOI: 10.1038/s41598-024-75947-4.

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