The role ofSox9in collagen hydrogel-mediated chondrogenic differentiation of adult mesenchymal stem cells (MSCs)

Abstract

Sox9 is a transcription factor that regulates chondrogenesis, but its role in the chondrogenic differentiation of mesenchymal stem cells (MSCs) triggered by materials is poorly understood. In this study, we investigated the effect of Sox9 interference on collagen-induced chondrogenesis and further collagen-based therapies for cartilage defects. In this paper, MSCs were infected with a vector carrying the Sox9 promoter and related markers were detected. A lentivirus-mediated vector targeting the silencing of the Sox9 gene was used in bone marrow-derived MSCs prior to being encapsulated in a collagen hydrogel. The collagen hydrogel as a sole inducer was also compared with transforming growth factor-β1 (TGF-β1). Before being implanted into the articular cartilage defect in rats, the cell-hydrogel pellets were cultured in vitro for 14 days. The effect of Sox9 transfection on cell proliferation was evaluated by measuring the total DNA content. Safranin-O staining and a biochemistry assay were performed to assess the synthesis and secretion of glycosaminoglycan (GAG) of MSCs. The real-time fluorescent quantitative polymerase chain reaction (RT-PCR) was performed to detect the gene expression levels of Col1a1, Col2a1, Acan and Sox9. The protein expression of collagen type II and collagen type I was analyzed by immunohistochemical analysis. Collagen alone significantly increased the luciferase activity of the Sox9 promoter, which was in parallel with the upregulation of cartilage specific markers. In vitro, the chondrogenic differentiation ability of MSCs was greatly inhibited after Sox9 interference, both in the collagen and TGF-β1-induced groups. In vivo, a further study showed that cartilage regeneration was arrested by using transfected MSCs with an injectable collagen gel or induced by TGF-β1. The results indicated that collagen may mediate Sox9 expression by providing a biomimetic microenvironment favoring cell condensation prior to chondrogenesis. The role of Sox9 regulation by materials is similar to that by growth factors, suggesting that well-designed scaffolds may replace growth factors in chondrogenesis. Thus, interventions targeting Sox9 may help improve articular cartilage repair.

Chondrogenic Commitment of human Bone Marrow Mesenchymal Stem Cells cultured under perfusion within a 3D collagen environment releasing hTGF\(\beta\)1

“…In the chondrogenic commitment of human MSCs, the transcription factorSox9 plays a key role and is considered as an early chondrogenic marker; its upregulation drives the correct chondrogenic phenotype, decreasing the hypertrophic drift of the cells (Jiang et al, 2018) which would gradually promote mineralization of hyaline cartilage and result in apoptosis and ossification (Mueller and Tuan, 2008). At day 16, supplementing 1 ng/mL of hTGFβ1, Sox9 levels doubled ( Figure 1a ); whereas, using 10 ng/mL, Sox9 showed a fourfold up-regulation ( Figure 1b ).…”

Tissue mimetic hyaluronan bioink containing collagen fibers with controlled orientation modulating cell morphology and alignment

“…In a minipig study colonization of the cell free Col matrix gave outcome comparable to matrix assisted chondrocyte implantation [48,49]. Jiang et al demonstrated superior chondrogenic differentiation of MSC embedded in Col compared to MSC only in a rat model [50]. On the other hand, HA has been combined with Col 1 or gelatin before with similar outcomes that chondrogenic differentiation is promoted in the composite compared to HA or Col only [51][52][53].…”

Advanced hydrogels for the repair of cartilage defects and regeneration

“…By using type I collagen as scaffold combined with stromal cell-derived factors-1 (SDF-1) as growth factor, Zhang et al successfully induced the migration and adhesion of C-MSCs and SM-MSCs and promoted the self-repair of partial thickness defects [ 30 ]. Another study conducted by Jiang et al indicated that collagen-based hydrogel encapsulated with MSCs could mediate the expression of Sox9 (a transcription factor regulates chondrogenesis), suggesting that appropriately designed hydrogel scaffold may work without growth factor [ 101 ]. Collagen can also be combined with other materials to form hybrid hydrogel scaffolds that have enhanced properties compared to the individual components.…”