Elena Martinez, E. | Search bioRxiv

bioRxiv2022

Soft topographical patterns trigger a stiffness-dependent cellular response to contact guidance

Directional migration is involved in multiple physiological and pathological processes. Among other external signals, the architecture of the extracellular matrix can trigger directed cell migration through a phenomenon known as contact guidance: cells elongate, align, and migrate along the direction set by aligned extracellular matrix fibers. This process involves the orientation of focal adhesions, actin, and tubulin cytoskeleton along the direction of those fibers. Contact guidance has been extensively studied on stiff materials with topographical grooved patterns. However, how it translates to softer physiologically relevant compliances is not known. Here we show that substrate stiffness modulates the cellular response to topographical contact guidance. We found that for fibroblasts, while focal adhesions and actin responded to topography independently of the stiffness, microtubules showed a stiffness-dependent response that regulates contact guidance. On the other hand, both clusters and single breast carcinoma epithelial cells displayed stiffness-dependent contact guidance migration, leading to more directional and efficient migration when increasing substrate stiffness. These results suggest that both matrix stiffening and alignment of extracellular matrix fibers cooperate during directional cell migration, and both should be accounted when studying processes such as cancer cell invasion. TeaserChanges in the stiffness of topographical patterns modify how mesenchymal and epithelial cells perform contact guidance.

biophysics↗

bioRxiv2021

Subepithelial Myofibroblasts Are Critical Regulators of Intestinal Epithelial Restoration

Fibroblasts reside underneath most epithelial tissues. In the intestine, recent studies have shown that fibroblast migration contributes to tissue morphogenesis and wound healing. Yet, whether physical interactions between epithelial cells and fibroblasts contribute to epithelial movement remains elusive. Here, we show that subepithelial fibroblast alignment enhances directed and persistent migration of organoid-derived intestinal epithelia. Using a reconstituted epithelial-stromal gap-closure model, we demonstrate that direct contact with fibroblasts improves gap closure by promoting cell alignment, sustaining tissue integrity, and synchronizing crypt-villus migration. Fibroblasts undergo long-range ordering to align perpendicularly to the epithelial front and deposit protein paths that act as guidance features to direct epithelial migration. In parallel, epithelial cells acquire a wound-associated epithelial-like phenotype, but insufficient to explain the effects of fibroblast contact. Our findings uncover a dual role for intestinal fibroblasts in epithelial repair, coordinating both biochemical and physical cues to ensure efficient and cohesive migration.

cell biology↗