Altered Expression of Wnt Signaling Pathway Components in Osteogenesis of Mesenchymal Stem Cells in Osteoarthritis Patients

Abstract

IntroductionOsteoarthritis (OA) is characterized by altered homeostasis of joint cartilage and bone, whose functional properties rely on chondrocytes and osteoblasts, belonging to mesenchymal stem cells (MSCs). WNT signaling acts as a hub integrating and crosstalking with other signaling pathways leading to the regulation of MSC functions. The aim of this study was to evaluate the existence of a differential signaling between Healthy and OA-MSCs during osteogenesis.MethodsMSCs of seven OA patients and six healthy controls were isolated, characterised and expanded. During in vitro osteogenesis, cells were recovered at days 1, 10 and 21. RNA and protein content was obtained. Expression of WNT pathway genes was evaluated using RT-qPCR. Functional studies were also performed to study the MSC osteogenic commitment and functional and post-traslational status of β-catenin and several receptor tyrosine kinases.ResultsSeveral genes were downregulated in OA-MSCs during osteogenesis in vitro. These included soluble Wnts, inhibitors, receptors, co-receptors, several kinases and transcription factors. Basal levels of β-catenin were higher in OA-MSCs, but calcium deposition and expression of osteogenic genes was similar between Healthy and OA-MSCs. Interestingly an increased phosphorylation of p44/42 MAPK (ERK1/2) signaling node was present in OA-MSCs.ConclusionOur results point to the existence in OA-MSCs of alterations in expression of Wnt pathway components during in vitro osteogenesis that are partially compensated by post-translational mechanisms modulating the function of other pathways. We also point the relevance of other signaling pathways in OA pathophysiology suggesting their role in the maintenance of joint homeostasis through modulation of MSC osteogenic potential.

The Role of Wnt Pathway in the Pathogenesis of OA and Its Potential Therapeutic Implications in the Field of Regenerative Medicine

“…The most common conservative management of OA is by intra-articular injection: in recent times, traditional products such as corticosteroids and hyaluronic acid have been flanked by novel therapies based on immunomodulatory molecules and also on “autologous” derivatives such as PRP and MSCs that have the potential advantage of minimizing side effects due to their autologous nature [ 52 ]. Although limited evidence suggests that these biologic products could exert a modulation on the Wnt pathway [ 3 , 45 , 46 , 53 ], further studies are needed to understand which mechanisms are involved in Wnt-pathway modulation and how to take full advantage of PRP and MSCs concentrate in the control of OA progression. These powerful biologic products can be regarded as a reservoir of many bioactive molecules: understanding their role and the pathways they can influence will open the possibility of manipulating these products to obtain “autologous” drugs with specific biologic actions within the joint.…”

Excessive Activation of TLR4/NF-κB Interactively Suppresses the Canonical Wnt/β-catenin Pathway and Induces SANFH in SD Rats

“…For instance, Wnt-5A plays an essential role in IL-1β-mediated cartilage destruction 39 . Other evidence suggested that the genesis of SANFH is closely connected with its degradation and that of its secondary cascade target genes related to osteogenesis, angiogenesis, and adipocyte 40 – 42 . In the present experiment in vivo , PDTC administration blocked NF-κB activation, relieved inflammatory response and necrosis incidence, and upregulated the Wnt pathway and subsequent osteogenesis and angiogenesis concurrently.…”

Molecular Mechanisms of Obesity-Induced Osteoporosis and Muscle Atrophy

“…The Wnt family of highly conserved secreted glycoproteins is rich in cysteine residues and controls not only the vital developmental processes of cell fate and polarity but also some cell maintenance processes. In humans, more than 19 Wnts, 10 FZD receptors, and 2 co-receptors (LRP-5, LRP-6) have been identified so far (Tornero et al, 2015 ). Among several Wnt signaling pathways, the Wnt/β-cat dependent (canonical) pathway has been well-characterized (Kim J. H. et al, 2013 ).…”