Simvastatin Enhances the Chondrogenesis But Not the Osteogenesis of Adipose-Derived Stem Cells in a Hyaluronan Microenvironment.

Shun-Cheng Wu,Ling-Hua Chang,Jhen-Wei Chen,Je-Ken Chang,Chung-Hwan Chen,Yi-Shan Lin,Mei-Ling Ho,Che-Wei Wu,Chih-Hsiang Chang

doi:10.3390/biomedicines9050559

Abstract

Directing adipose-derived stem cells (ADSCs) toward chondrogenesis is critical for ADSC-based articular cartilage regeneration. Simvastatin (SIM) was reported to promote both chondrogenic and osteogenic differentiation of ADSCs by upregulating bone morphogenetic protein-2 (BMP-2). We previously found that ADSC chondrogenesis is initiated and promoted in a hyaluronan (HA) microenvironment (HAM). Here, we further hypothesized that SIM augments HAM-induced chondrogenesis but not osteogenesis of ADSCs. ADSCs were treated with SIM in a HAM (SIM plus HAM) by HA-coated wells or HA-enriched fibrin (HA/Fibrin) hydrogel, and chondrogenic differentiation of ADSCs was evaluated. SIM plus HAM increased chondrogenesis more than HAM or SIM alone, including cell aggregation, chondrogenic gene expression (collagen type II and aggrecan) and cartilaginous tissue formation (collagen type II and sulfated glycosaminoglycan). In contrast, SIM-induced osteogenesis in ADSCs was reduced in SIM plus HAM, including mRNA expression of osteogenic genes, osteocalcin and alkaline phosphatase (ALP), ALP activity and mineralization. SIM plus HAM also showed the most effective increases in the mRNA expression of BMP-2 and transcription factors of SOX-9 and RUNX-2 in ADSCs, while these effects were reversed by CD44 blockade. HAM suppressed the levels of JNK, p-JNK, P38 and p-P38 in ADSCs, and SIM plus HAM also decreased SIM-induced phosphorylated JNK and p38 levels. In addition, SIM enhanced articular cartilage regeneration, as demonstrated by implantation of an ADSCs/HA/Fibrin construct in an ex vivo porcine articular chondral defect model. The results from this study indicate that SIM may be an enhancer of HAM-initiated MSC-based chondrogenesis and avoid osteogenesis.

Highlights

Damaged articular cartilage has a limited capacity for self-repair [1,2]
A similar effect on bone morphogenetic protein-2 (BMP-2) protein expression was observed in the four groups of Adipose-derived stem cells (ADSCs) on day 3 (Figure 5B). These results show that SIM plus HA microenvironment (HAM) further enhances SIM-induced bone morphogenetic protein (BMP)-2 expression in ADSCs, and the optimal effect was observed on day 3 (Figure 5A,B)
We proposed that the HAM-reduced osteogenic effect of SIM on ADSCs may be due to interference with RUNX-2-regulated expression of alkaline phosphatase (ALP) and OC and subsequent mineralization

Summary

Introduction

Cell-based tissue engineering may provide an alternative treatment method for cartilage defects [1,2], and chondrocytes or mesenchymal stem cells (MSCs) have been used to regenerate articular cartilage defects. Due to the poor proliferation capacity and de-differentiation of chondrocytes caused by in vitro expansion, using MSCs as the cell source is becoming an important approach for articular cartilage tissue engineering [3,4,5]. Adipose-derived stem cells (ADSCs) are thought to be a beneficial cell source for MSC-based articular cartilage tissue engineering due to their ease of harvest, high yield rate, and chondrogenic differentiation potential [6,7,8]. The important concern in applying BMP-2 to stimulate

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Discussion

Conclusion