Native cartilage has low capacity for regeneration because it has very few progenitor cells. Mesenchymal stem cells (MSCs) derived from both human umbilical cord blood (hUCB) and human umbilical cord (hUC) have been used as stem cell sources for cartilage injury repair. However, production of hyaline cartilage from MSCs remains problematic. The paracrine factors released by chondrocytes could induce chondrogenic differentiation of MSCs. We induced chondrogenesis of hUCB-derived MSCs (hUCB-MSCs) and hUC-derived MSCs (hUC-MSCs) using culture medium from chondrocytes. We analyzed the expression of collagen type I alpha 1 (Col1a1), collagen type II alpha 1 (Col2a1), and SRY-box 9 (SOX 9), by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and immunofluorescence assays. To elucidate the differentiation mechanism, we further analyzed the transforming growth factor-β1 (TGF-β1) concentration in the culture medium of chondrocytes by enzyme-linked immunosorbent assay (ELISA). Meanwhile, Cell Counting Kit-8 (CCK-8) assays were used to evaluate cell viability. The hUC-MSCs had higher chondrogenic differentiation potential than hUCB-MSCs. We found that the culture medium of chondrocytes contained TGF-β1, which was the likely cause of chondrogenic differentiation. In addition, we found that hUC-MSCs had higher proliferation ability than hUCB-MSCs by testing the cell viability after differentiation. Overall, we compared the chondrogenic potential of hUCB-MSCs and hUC-MSCs after induction with chondrocyte culture medium and found that hUC-MSCs showed higher differentiation potential and higher proliferation ability than hUCB-MSCs. So, compared to hUCB-MSCs, hUC-MSCs are a better source of chondrocytes for cartilage repair under induction with chondrocyte culture medium.
Abstract
Background
Native cartilage has low capacity for regeneration because it has very few progenitor cells. Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) and human umbilical cord-derived MSCs (hUC-MSCs) have been employed as promising sources of stem cells for cartilage injury repair. Reproduction of hyaline cartilage from MSCs remains a challenging endeavor. The paracrine factors secreted by chondrocytes possess the capability to induce chondrogenesis from MSCs.
Methods
The conditioned medium derived from chondrocytes was utilized to induce chondrogenic differentiation of hUCB-MSCs and hUC-MSCs. The expression levels of collagen type I alpha 1 chain (Col1a1), collagen type II alpha 1 chain (Col2a1), and SRY-box transcription factor 9 (SOX9) were assessed through quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB), and immunofluorescence (IF) assays. To elucidate the mechanism of differentiation, the concentration of transforming growth factor-β1 (TGF-β1) in the conditioned medium of chondrocytes was quantified using enzyme-linked immunosorbent assay (ELISA). Meanwhile, the viability of cells was assessed using Cell Counting Kit-8 (CCK-8) assays.
Results
The expression levels of Col2a1 and SOX9 were found to be higher in induced hUC-MSCs compared to those in induced hUCB-MSCs. The conditioned medium of chondrocytes contained TGF-β1. The CCK-8 assays revealed that the proliferation rate of hUC-MSCs was significantly higher compared to that of hUCB-MSCs.
Conclusions
The chondrogenic potential and proliferation capacity of hUC-MSCs surpass those of hUCB-MSCs, thereby establishing hUC-MSCs as a superior source of seed cells for cartilage tissue engineering.
Animal Models and Experimental Medicine, EarlyView. Read More