Biology subjects

FERRAND, A.

Publications and source records attributed to FERRAND, A..

5 recordsLinked to original sources

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↗

bioRxiv2026

Progastrin activates colonic fibroblasts and induces a paracrine pro-migratory program in colorectal cancer cells

PurposeProgastrin, aberrantly expressed in colorectal cancer (CRC), is an established trophic factor for tumour epithelial cells. Whether it also promotes CRC progression by reprogramming stromal fibroblasts remains unclear. We investigated progastrin-induced colonic fibroblast activation and its functional consequences on CRC cell migration. MethodsFibroblast activation was assessed in the colonic mucosa of hGAS mice and in the human normal colonic fibroblast line CCD18Co exposed to synthetic progastrin. The impact of tumour-derived progastrin on epithelial cell motility was analysed using HCT116 cells expressing a control shRNA (shLuc) or a progastrin-targeting shRNA (shPG) in transwell migration assays performed with or without fibroblasts. Candidate paracrine mediators were evaluated by RT-qPCR, ELISA and neutralization experiments, and signalling was interrogated using the PI3K inhibitor LY294002. ResultsColonic fibroblasts from hGAS mice displayed stromal FAP and SMA expression, indicating fibroblast activation in vivo. In CCD18Co cells, progastrin increased FAP and SMA protein levels. Fibroblasts enhanced HCT116 cell migration. This effect was stronger when tumour cells expressed progastrin or when fibroblasts were preconditioned by progastrin-producing HCT116 cells. Progastrin induced CXCL12/SDF-1 and CXCL8/IL-8 expression and secretion by fibroblasts, and neutralization of either chemokine abrogated the additional migratory effect conferred by progastrin-activated fibroblasts. Progastrin triggered sustained Akt phosphorylation in fibroblasts, while PI3K inhibition suppressed CXCL12 and CXCL8 secretion and abolished fibroblast-dependent tumour cell migration. ConclusionThese data identify a stromal dimension of progastrin signalling in CRC and support a model in which tumour-derived progastrin activates colonic fibroblasts and elicits a PI3K/Akt-dependent paracrine programme that enhances CRC cell migration.

cancer biology↗

bioRxiv2025

Non-destructive assessment of multi-material micro-tissue mechanics reveals the critical role of rigidity gradients in tumour growth and pressure

Probing stiffness anisotropies in three-dimensional materials non-destructively is a major challenge in disciplines as diverse as aeronautics and medicine. While the former typically relies on various mechanical tests--such as tensile, compression, bending, and shear--performed on sample parts, the latter often employs acoustic techniques or wave propagation through matter. The choice of techniques will depends on the size of the sample of interest and the desired resolution. In our case, to probe the mechanical properties of sub-millimetre micro-tissues, it is necessary to use methods with high resolution and as furtive as possible. We present a method based, 1/ on imaging the displacement of microbeads within a hydrogel resulting from the growth of a three-dimensional micro-tissue and, 2/ on finite element modelling of the deformations underlying bead displacements. This approach allows us to determine the elastic properties of the hydrogel and, in particular, to show that beyond a certain thickness, incomplete cross-linking of the hydrogel results in a stiffness gradient. We show that when the micro-tissue contacts with an immediately rigid alginate wall, the pressure exerted over time increases very rapidly, whereas when the micro-tissue encounters a substrate with a stiffness gradient, the pressure increase is more gradual. Uncovering this could provide a better understanding of the role of tumour microenvironment stiffness in metastatic escape processes.

biophysics↗

bioRxiv2025

Human Colon Microphysiological System Reproducing Tissue Mechanical Microenvironment With Active Microfluidic Control and Imaging Capacity

In vitro artificial colonic micro-devices that better replicate complex in vivo systems are essential tools for advancing our understanding of human gut (patho)physiology. Micro-physiological systems (MPS) offer controlled environments, enabling precise manipulation of tissue topography, rigidity and nutrient flow. We present the EnView system configured as a human colon-based MPS that faithfully replicates the 3D topography and matrix stiffness of the human colonic environment using an interpenetrating network of polyacrylamide and collagen I hydrogels, and enabling the culture of human colonic epithelium for weeks. The EnView system integrates a microfluidic chamber with active control of apical/luminal and basal/stromal compartments, allowing for in situ imaging and monitoring. Human colonic epithelial Caco-2 cells cultured up to 21 days in this system follow the crypt topography and formed a polarized epithelial monolayer. This innovative MPS recapitulates in vitro a human colon epithelium with its 3D matrix topology and stiffness control, integrates a microfluidic chamber allowing active control of the apical/luminal and basal/stromal compartments by accurate injection, as well as in situ imaging. TeaserHuman gut-on-chip reproducing tissue mechanical properties with active microfluidic control for 3D tissue characterization.

bioengineering↗

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↗