Subchondral bone influences chondrogenic differentiation and collagen production of human bone marrow-derived mesenchymal stem cells and articular chondrocytes

Abstract

IntroductionOsteoarthritis (OA) is characterized by an imbalance in cartilage and underlying subchondral bone homeostasis. We hypothesized that signals from the subchondral bone may modulate production of matrix components, alter chondrogenic differentiation potential of cocultured bone marrow-derived mesenchymal stem cells (BMSC) and induce a phenotypic shift in differentiated OA chondrocytes.MethodsWe established a novel coculture model between BMSC, mixed cultures (BMSC and chondrocytes) and chondrocytes embedded in fibrin gel with OA and normal subchondral bone explants (OAB and NB). Tissues and cells were either derived from OA or trauma patients. In addition, we used adipose-derived stem cells (ASC) from liposuction. With gene expression analysis, biochemical assays, immunofluorescence and biomechanical tests we characterized the properties of newly generated extracellular matrix (ECM) from chondrocytes and chondrogenically differentiating BMSC cocultured with OAB or NB in comparison with monocultures (cultures without bone explants).ResultsOverall, gene expression of collagens of OAB and NB cocultured cells was reduced compared to monocultures. Concomitantly, we observed significantly lower collagen I, II and III and glycosaminoglycan (GAG) production in OAB cocultured cell lysates. In parallel, we detected increased concentrations of soluble GAGs and basic fibroblast growth factor (bFGF), interleukin (IL)-6 and IL-8 in supernatants of OAB and NB cocultures mainly at early time points. IL-1ß concentration was increased in supernatants of OAB cocultures, but not in NB cocultures. Cell-free NB or OAB explants released different amounts of IL-1ß, bFGF and soluble GAG into cell culture supernatants. In comparison to cocultures, monocultures exhibited higher Young’s modulus and equilibrium modulus. Stimulation of monocultures with IL-1ß led to a downregulation of aggrecan (ACAN) gene expression and in general to induced matrix metalloprotease (MMP)2, MMP3 and MMP-13 gene expression while IL-6 and IL-8 stimulation partly reduced ACAN, MMP3 and MMP-13 gene expression.ConclusionsOur results suggest an alteration of molecular composition and mechanical properties of the newly formed ECM in subchondral bone cocultures. We suggest that soluble factors, that is interleukins and bFGF, released in cocultures exert inhibitory effects on collagen and temporary effects on proteoglycan production, which finally results in a reduction of mechanical strength of newly formed fibrillar networks.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-014-0453-9) contains supplementary material, which is available to authorized users.

Comparative effectiveness of two methods for inducing osteoarthritis in a novel animal model, the Diannan small-ear pig1

“…The Diannan small-ear pig can be used as an animal model for OA research because it is easy to obtain enough pathological tissues, and it is convenient for gross observation. Although two methods can induce obvious cartilage degeneration in pigs, an interesting and signi cant discovery of this study was that the chemical injection exhibited more and faster cartilage erosion, proteoglycan loss, and more serious synovial in ammation, which were all similar to those seen in human OA [26]. To sum up, intraarticular injection of papain is a better choice to induce OA due to less trauma and more e cient simulation of OA pathological processes.…”

Role of proteoglycans on the biochemical and biomechanical properties of dentin organic matrix

“…Correlations between an imbalance of PGs synthesis or concentration with tissue strength and biodegradability are reported in cartilage and bone (Leyh et al, 2014; Martel-Pelletier, Kwan Tat, & Pelletier, 2010), while it is unclear if PGs have any role in this aspect in dentin. Moreover, there is a lack of knowledge in the specific mechanisms involved in the participation of these biomacromolecules on the bulk tissue mechanical behavior and overall ECM biostability.…”

Effects of intra-articular injection of mesenchymal stem cells associated with platelet-rich plasma in a rabbit model of osteoarthritis

“…This effect can be regulated by different signaling factors secreted by the resident chondrocytes or osteoblasts (Birmingham et al, 2012). In vivo MSC differentiation is triggered by the interactions between signaling molecules emitted by local and neighboring cells, which are transduced via extracellular or intracellular pathways associated with MSC membrane receptors, cytokines and soluble growth factors, extracellular matrix proteins such as collagen and proteoglycans, or by direct interactions with resident chondrocytes (Leyh et al, 2014). Furthermore, Van Pham et al (2013) stated that PRP not only stimulates MSC proliferation, but can also induce its differentiation into chondrogenic cells.…”