Chondrogenic differentiation of embryonic stem cells using mechanotransductive 3-D PDMS scaffolds

Abstract

Embryonic stem cells (ESCs) are an ideal source for cell therapy and regenerative medicine.  ESCs must be differentiated prior to their use for therapeutic applications.  However, homogeneous differentiation of ESCs in vitro has proven to be challenging.  We hypothesized that both biological and mechanical cues contribute to the specific differentiation of ESCs in vivo . This was tested by mimicking the in vivo microenvironment to differentiate ESCs into chondrogenic lineage using highly elastic polydimethylsiloxane (PDMS) scaffolds and the application of mechanical compression in vitro . ESCs seeded in PDMS scaffolds subjected to static compressive stress resulted in significant upregulation of genes, Sox9, Col2, and Acan , involved in early chondrogenic differentiation . However, the compressive stress did not affect expression of the late hypertrophic markers, Runx2 , Col10, and Mmp13 , signifying induction of ESCs into early chondroprogenitors. Application of mechanical stress increased expression of mechanical signaling genes, Rhoa , Yap, and Taz . The chondroinductive role of Rhoa was confirmed by the inhibition of RhoA signaling by CCG-1423, which resulted in decreased transcriptional and translational expression of chondrogenic markers. Based on these findings, we proposed a strategy for compression induced chondrogenic differentiation in mechanotransductive 3-D PDMS scaffolds.