Differentiation of bone marrow-derived mesenchymal stem cells into chondrocytes using chondrocyte extract.

Reprogramming cells using cell extracts is an effective method for harvesting cells of interest. The aim of this study was to investigate the chondrogenic transdifferentiation potential of swine bone marrow-derived mesenchymal stem cells (BM-MSCs) by culturing with chondrocyte extract, using monolayer and micromass culture. Chondrogenic-specific markers were detected via reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence. After 7 days of induction in monolayer culture, BM-MSCs reversibly permeabilized with streptolysin O (SLO), a bacterial exotoxin that is capable of forming large pores in the plasma membrane of mammalian cells, and expressed chondrocyte‑specific genes such as type II collagen (COL II) and aggrecan. A positive protein expression of COL II was also observed. However, BM-MSCs treated without SLO did not express the related genes and proteins. The transition of reprogrammed BM-MSCs was lost 14 days later. By using micromass culture, reprogrammed BM-MSCs were able to maintain the change until the 14th day. In summary, permeabilized BM-MSCs were transiently transdifferentiated into chondrocytes by co-culturing with the chondrocyte extract. Moreover, a high-density culture method was able to increase the time in which the phenotypic change was maintained.