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Matrix molecule influence on chondrocyte phenotype and proteoglycan 4 expression by alginate‐embedded zonal chondrocytes and mesenchymal stem cells
Author(s) -
Coates Emily E.,
Riggin Corinne N.,
Fisher John P.
Publication year - 2012
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.22166
Subject(s) - chondrogenesis , chondrocyte , mesenchymal stem cell , microbiology and biotechnology , cartilage , chemistry , aggrecan , messenger rna , extracellular matrix , matrix (chemical analysis) , proteoglycan , cartilage oligomeric matrix protein , sox9 , type ii collagen , stem cell , biology , gene expression , anatomy , pathology , biochemistry , articular cartilage , medicine , osteoarthritis , gene , alternative medicine , chromatography
Articular cartilage resists load and provides frictionless movement at joint surfaces. The tissue is organized into the superficial, middle, deep, and calcified zones throughout its depth, each which serve distinct functions. Proteoglycan 4 (PRG4), found in the superficial zone, is a critical component of the joint's lubricating mechanisms. Maintenance of both the chondrocyte and zonal chondrocyte phenotype remain challenges for in vitro culture and tissue engineering. Here we investigate the expression of PRG4 mRNA and protein by primary bovine superficial zone chondrocytes, middle/deep zone chondrocytes, and mesenchymal stem cells encapsulated in alginate hydrogels with hyaluronic acid (HA) and chondroitin sulfate (CS) additives. Chondrogenic phenotype and differentiation markers are evaluated by mRNA expression, histochemical, and immunohistochemical staining. Results show middle/deep cells express no measurable PRG4 mRNA by day 7. In contrast, superficial zone cells express elevated PRG4 mRNA throughout culture time. This expression can be significantly enhanced up to 15‐fold by addition of both HA and CS to scaffolds. Conversely, PRG4 mRNA expression is downregulated (up to 5‐fold) by CS and HA in differentiating MSCs, possibly due to build up of entrapped protein. HA and CS demonstrate favorable effects on chondrogenesis by upregulating transcription factor Sox9 mRNA (up to 4.6‐fold) and downregulating type I collagen mRNA (up to 18‐fold). Results highlight the important relationship between matrix components and expression of critical lubricating proteins in an engineered cartilage scaffold. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1886–1897, 2012