Hamel, D. | bioRxiv Science

bioRxiv2026

IBD-Derived Colonic Fibroblasts Exhibit an Osteopontin-Enriched Secretome, and Osteopontin Restrains Human Colonic Organoid Maturation

Background: Intestinal fibroblasts are extensively remodeled in inflammatory bowel disease (IBD), yet the soluble stromal signals that directly influence epithelial maturation remain incompletely understood. We examined whether fibroblasts derived from inflamed IBD colon display an osteopontin (OPN; SPP1)-enriched secretory phenotype and whether extracellular OPN directly modifies non-neoplastic human colonic epithelium. Methods: Conditioned media from 5 noninflamed-associated fibroblast (NAF) and 4 inflammatory-associated fibroblast (IAF) cultures were analyzed in the validated multi-donor cytokine-array matrix, with orthogonal SPP1 RT-qPCR validation in a complementary fibroblast cohort. Recombinant OPN was then tested in human colonic organoids from 3 donors using donor-resolved molecular and functional analyses under standard, fibroblast-conditioned, and WNT-modified culture conditions. Donor identity defined biological replication. Results: OPN showed the strongest positive rank-based separation between IAF and NAF cultures: all 4 IAF values were higher than all 5 NAF values (Cliff's delta=1.00; exact Mann-Whitney P=0.0159; median ratio=3.64; Benjamini-Hochberg q=.19). Fibroblast RT-qPCR showed approximately 10-fold higher mean SPP1 expression in IAF than NAF cultures (P<.05). In organoids, OPN consistently reduced KRT20, FABP1, CA2, and MUC2 from Day 5 to Day 9. SOX9, HES1, and NOTCH1 increased at Day 9, whereas LGR5 and ALDH provided no evidence of canonical stem-cell expansion. Organoid-area and EdU responses were modest and donor dependent. Conclusions: IBD-derived colonic fibroblasts can display an OPN-enriched secretory phenotype. In human colonic organoids, OPN is sufficient to impair epithelial maturation, whereas its effects on growth and proliferation are variable and depend on the surrounding niche.

physiology↗

bioRxiv2023

Deciphering the interplay between biology and physics: finite element method-implemented vertex organoid model raises the challenge

Understanding the intertwining of biology and mechanics in tissue architecture is a challenging issue, especially when it comes to the 3D tissue organization. Addressing this challenge requires both a biological model allowing multiscale observations from the cell to the tissue, and theoretical and computational approaches allowing the generation of a synthetic model, relevant to the biological model, and allowing access to the mechanical constraints experienced by the tissue. Here, using human colon epithelium monolayer organoid as biological model, and combining vertex and FEM approaches, we generated a comprehensive elastic finite element model of the human colon organoid and demonstrated its flexibility. This FEM model provides a basis for relating cell shape, tissue deformation, and strain at the cellular level due to imposed stresses. In conclusion, we demonstrated that the combination of vertex and FEM approaches allows for better modeling of the alteration of organoid morphology over time and better assessment of the mechanical cues involved in establishing the architecture of the human colon epithelium.

biophysics↗