Substrate Stiffness Modulates Renal Progenitor Cell Properties via a ROCK-Mediated Mechanotransduction Mechanism

Abstract

Stem cell (SC)-based tissue engineering and regenerative medicine (RM) approaches may provide alternative therapeutic strategies for the rising number of patients suffering from chronic kidney disease. Embryonic SCs and inducible pluripotent SCs are the most frequently used cell types, but autologous patient-derived renal SCs, such as human CD133+CD24+ renal progenitor cells (RPCs), represent a preferable option. RPCs are of interest also for the RM approaches based on the pharmacological encouragement of in situ regeneration by endogenous SCs. An understanding of the biochemical and biophysical factors that influence RPC behavior is essential for improving their applicability. We investigated how the mechanical properties of the substrate modulate RPC behavior in vitro. We employed collagen I-coated hydrogels with variable stiffness to modulate the mechanical environment of RPCs and found that their morphology, proliferation, migration, and differentiation toward the podocyte lineage were highly dependent on mechanical stiffness. Indeed, a stiff matrix induced cell spreading and focal adhesion assembly trough a Rho kinase (ROCK)-mediated mechanism. Similarly, the proliferative and migratory capacity of RPCs increased as stiffness increased and ROCK inhibition, by either Y27632 or antisense LNA-GapmeRs, abolished these effects. The acquisition of podocyte markers was also modulated, in a narrow range, by the elastic modulus and involved ROCK activity. Our findings may aid in 1) the optimization of RPC culture conditions to favor cell expansion or to induce efficient differentiation with important implication for RPC bioprocessing, and in 2) understanding how alterations of the physical properties of the renal tissue associated with diseases could influenced the regenerative response of RPCs.

Electrospinning Fabrication Methods to Incorporate Laminin in Polycaprolactone for Kidney Tissue Engineering

“…This impact has been demonstrated with other proteins and polymers [34,46]. An increase in Young's modulus have been linked to positive effects such as cell proliferation and spreading, but also negative responses in particular apoptosis [47,48]. This fundamental also applies to decreased stiffness where studies have shown that there can be a positive influence such as increased focal adhesion properties and also some negatives with decreased cell motility [49,50].…”

Podocytopathies

“…The absence of APOL1 also promotes parietal epithelial cell quiescence; the microRNA miR-193a suppresses APOL1 translation 59 . Under conditions of mechanical stress 60 , impaired APOL1-miR-193a axis (for example, in those with the G1 or G2 genotype) 59 or persistent NOTCH expression 61 , activated parietal epithelial cells cannot properly differentiate into podocytes and contribute to the formation of hyperplastic lesions and fibrous lesions, including FSGS 58,62 , by synthesizing and releasing extracellular matrix 63 (FiG. 4).…”

Mechanotransduction as a major driver of cell behaviour: mechanisms, and relevance to cell organization and future research

“…However, it was rapidly recognized that substratum stiffness strongly influenced the outcome of cell receptor interaction with bound ligands [ 15 , 16 ]. Thus, when renal cells were deposited on collagen-coated hydrogels with an elastic modulus 2 ranging between 0.2 kPa and 50 kPa, cell proliferation rate increased proportionally to the substrate stiffness [ 17 ]. However, tendon-derived stem cells deposited on gelatin hydrogels with a stiffness ranging between about 2 kPa and 25 kPa displayed more active growth on softer surfaces [ 18 ].…”