Targeting twist to promote stem cell based cartilage repair

Rapid induction of Mesenchymal stem cells (MSCs) chondrogenic differentiation during therapeutic transplantation remains extremely challenging. Here the author undertook a study to determine if twist1 inhibition by shRNA could be utilized to accelerate human Placenta-derived MSCmediated cartilage repair in a mouse cartilage defect model. Our data clearly indicated that silencing twist1 significantly enhanced chondrogenesis by showing increased alcian blue staining enhanced Col-II expression when compared to control wild type PMSCs. Importantly, the in vivo transplantation of twist1 deficient PMSCs into knee joint cartilage defects had a significantly enhanced cartilage formation by showing stronger alcian blue and Col-II staining in cartilage defect area. Finally, the PCR data further confirmed an increased expression of chondrogenic markers Sox9, Col-II and aggrecan in knee joint tissue with transplantation of twist1 deficient PMSCs. Collectively; these findings demonstrate that PMSCs are a favourable cell source for cartilage repair and silencing transcript factor twist1 could accelerate PMSC differentiation into chondrocyte under the cartilage micro-environment in vivo.