Influence of Cartilage Extracellular Matrix Molecules on Cell Phenotype and Neocartilage Formation

Abstract

Interaction between chondrocytes and the cartilage extracellular matrix (ECM) is essential for maintaining the cartilage's role as a low-friction and load-bearing tissue. In this study, we examined the influence of cartilage zone-specific ECM on human articular chondrocytes (HAC) in two-dimensional and three-dimensional (3D) environments. Two culture systems were used. SYSTEM 1: HAC were cultured on cell-culture plates that had been precoated with the following ECM molecules for 7 days: decorin, biglycan, tenascin C (superficial zone), collagen type II, hyaluronan (HA) (middle and deep zones), and osteopontin (deep zone). Uncoated standard culture plates were used as controls. Expanded cells were examined for phenotypic changes using real-time polymerase chain reaction. In addition, expanded cells were placed into high-density pellet cultures for 14 days. Neocartilage formation was assessed via gene expression and histology evaluations. SYSTEM 2: HAC that were cultured on untreated plates and encapsulated in a 3D alginate scaffold were mixed with one of the zone-specific ECM molecules. Cell viability, gene expression, and histology assessments were conducted on 14-day-old tissues. In HAC monolayer culture, exposure to decorin, HA, and osteopontin increased COL2A1 and aggrecan messenger RNA (mRNA) levels compared with controls. Biglycan up-regulated aggrecan without a significant impact on COL2A1 expression; Tenascin C reduced COL2A1 expression. Neocartilage formed after preculture on tenascin C and collagen type II expressed higher COL2A1 mRNA compared with control pellets. Preculture of HAC on HA decreased both COL2A1 and aggrecan expression levels compared with controls, which was consistent with histology. Reduced proteoglycan 4 (PRG4) mRNA levels were observed in HAC pellets that had been precultured with biglycan and collagen type II. Exposing HAC to HA directly in 3D-alginate culture most effectively induced neocartilage formation, showing increased COL2A1 and aggrecan, and reduced COL1A1 compared with controls. Decorin treatments increased HAC COL2A1 mRNA levels. These data indicate that an appropriate exposure to cartilage-specific ECM proteins could be used to enhance cartilage formation and to even induce the formation of zone-specific phenotypes to improve cartilage regeneration.

Protocatechuic acid benefits proliferation and phenotypic maintenance of rabbit articular chondrocytes: An in vitro study

“…Proteoglycans are crucial components of the ECM (19). The ECM is responsible for maintaining the cartilage load-bearing capacity (20), and also plays a vital role in chondrocyte phenotype (21). Consistent with the increase in GAG production, PCA was demonstrated to upregulate the gene expression of Sox9, collagen II and aggrecan (Fig.…”

Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

“…and other additives (e.g., ITS+ and Ham’s F-12 medium) to promote cell growth and proliferation (158-160). Matrix-coated culture flasks have also been used to promote cell adhesion and provide chondroinductive cues (161, 162). …”

Matricellular Proteins in the Trabecular Meshwork: Review and Update

“…160,161,[165][166][167] Like its fellow matricellular proteins SPARC and TSP-1, tenascin-C regulates cellular adhesion and migration in a tissue-dependent manner. 168 One mechanism by which this occurs may include interference with integrin-mediated cellular interaction with fibronectin.…”