Microenvironmental stiffness directs microtubule perturbation in chondrocyte mitosis via ILK-refilinB/Smad3 axis.

Cells actively sense and transduce microenvironmental mechanical inputs into chemical signals via cytoskeletal rearrangements. During these mechanosensation and mechanotransduction processes, the role of the actin cytoskeleton is well-understood, whereas the role of the tubulin cytoskeleton remains largely elusive. Here, we report the dynamic changes in microtubules in response to microenvironmental stiffness during chondrocyte mitosis. Mechanical stiffness was found to be coupled with microtubule generation, directing microtubule dynamics in mitotic chondrocytes. Refilin B was found to be a key regulator of microtubule assembly in chondrocytes in response to mechanical stiffness. It was found to play its role in microtubule formation via the p-Smad3 signaling pathway. Additionally, integrin-linked kinase (ILK), triggered by mechanical stiffness, was found to play an indispensable role in the process of microtubule dynamics mediated by refilin B. Our data emphasizes stiffness-mediated dynamic changes in the microtubules of chondrocytes in a quiescent state (G0) and at anaphase, which improves our understanding of the mechanical regulation of microtubule assembly during the chondrocyte cell cycle and provides insights into microenvironment mechanics during tissue maintenance, wound healing, and disease occurrence.