Prospective Isolation of Chondroprogenitors from Human iPSCs Based on Cell Surface Markers Identified using a CRISPR-Cas9-Generated Reporter

SUMMARY Articular cartilage shows little or no capacity for intrinsic repair, generating a critical need for regenerative therapies for joint injuries and diseases such as osteoarthritis. Human induced pluripotent stem cells (hiPSCs) offer a promising cell source for cartilage tissue engineering and in vitro human disease modeling; however, heterogeneity and off-target differentiation remain a challenge. We used a CRISPR-Cas9-edited COL2A1-GFP knock-in reporter hiPSC line, coupled with a surface marker screen, to identify a novel chondroprogenitor population expressing CD146, CD166, and PDGFRβ, but not CD45. Under chondrogenic culture conditions, these triple positive chondroprogenitor cells demonstrated decreased heterogeneity as measured by single cell RNA sequencing, as well as more robust and homogenous matrix production with significantly higher chondrogenic gene expression. Overall, this study has identified a unique hiPSC-derived subpopulation of chondroprogenitors that are CD146 + /CD166 + /PDGFRβ + /CD45 - and exhibit high chondrogenic potential, providing a purified cell source for cartilage tissue engineering or disease modeling studies.