Matrix stiffness-dependent regulation of immunomodulatory genes in human MSCs is associated with the lncRNA CYTOR

Previous studies have demonstrated that the physical properties of biomaterials can be adjusted to program therapeutically relevant functions in encapsulated mesenchymal stromal cells (MSCs). However, the intracellular pathways affected by mechanical cues in this cell type are not well understood. An understanding of the pertinent factors involved would not only aid in the rational design of substrates but also uncover targetable mechanisms that can facilitate the engineering of MSCs for cell therapies. Here, a bone marrow-mimetic hydrogel is employed to systematically explore the stiffness-responsive transcriptome of MSCs. High matrix rigidity impedes integrin-collagen adhesions which yields changes in cell morphology that are characterized by a contractile network of actin proximal to the cell membrane. This results in a suppression of ECM-regulatory genes involved in the remodeling of collagen fibrils and an upregulation of secreted immunomodulatory factors. Moreover, an investigation of long non-coding RNAs reveals that CYTOR contributes to these stiffness-driven changes in gene abundance. A robust knockdown of CYTOR using antisense oligonucleotides enhances the expression of numerous mechanoresponsive cytokines and chemokines to levels exceeding what is achievable by modulating matrix stiffness alone. Taken together, these findings emphasize the utility in studying previously unexplored mechanisms of mechanotransduction to inform novel strategies for enhancing the efficacy of MSC-based therapies.