A Human Osteochondral Tissue Model Mimicking Cytokine-Induced Key Features of Arthritis In Vitro.

Alexandra Damerau,Gerd-Rüdiger Burmester,Annemarie Lang,Moritz Pfeiffenberger,Frank Buttgereit,Timo Gaber,Marie-Christin Weber

doi:10.3390/ijms22010128

Abstract

Adequate tissue engineered models are required to further understand the (patho)physiological mechanism involved in the destructive processes of cartilage and subchondral bone during rheumatoid arthritis (RA). Therefore, we developed a human in vitro 3D osteochondral tissue model (OTM), mimicking cytokine-induced cellular and matrix-related changes leading to cartilage degradation and bone destruction in order to ultimately provide a preclinical drug screening tool. To this end, the OTM was engineered by co-cultivation of mesenchymal stromal cell (MSC)-derived bone and cartilage components in a 3D environment. It was comprehensively characterized on cell, protein, and mRNA level. Stimulating the OTM with pro-inflammatory cytokines, relevant in RA (tumor necrosis factor α, interleukin-6, macrophage migration inhibitory factor), caused cell- and matrix-related changes, resulting in a significantly induced gene expression of lactate dehydrogenase A, interleukin-8 and tumor necrosis factor α in both, cartilage and bone, while the matrix metalloproteases 1 and 3 were only induced in cartilage. Finally, application of target-specific drugs prevented the induction of inflammation and matrix-degradation. Thus, we here provide evidence that our human in vitro 3D OTM mimics cytokine-induced cell- and matrix-related changes—key features of RA—and may serve as a preclinical tool for the evaluation of both new targets and potential drugs in a more translational setup.

Highlights

The osteochondral unit is an essential part of the joint and commits the functional association of the articular cartilage, calcified cartilage and the subchondral bone
Scanning electron microscopy revealed that both mesenchymal stromal cell (MSC) and or pre-differentiated MSCs (oMSC) became adherent to the tricalcium phosphate (TCP) scaffold and invaded the TCP scaffold within 21 days (Figure 2B)
MSCs and oMSCs colonized the TCP scaffold within 21 days without any sign of cytotoxicity as demonstrated by the lack of differences in LDH release when compared to the spontaneous release of a TCP-free monolayer (ML), but a significant lower release compared to the positive control (Figure 2C)

Summary

Introduction

The osteochondral unit is an essential part of the joint and commits the functional association of the articular cartilage, calcified cartilage and the subchondral bone. Several pathologies have been demonstrated to affect the osteochondral unit e.g., microcracks, microedema, microbleeding, the development of subchondral bone cysts and osteophytes co-localizing with regions of articular cartilage damage [2,3,4]. All these changes are attributed to the degenerative joint disease osteoarthritis (OA) or chronic autoimmune-mediated joint inflammation such as found in rheumatoid arthritis (RA), which is a systemic autoimmune disease. During RA, MMP1, MMP3, MMP8, and MMP13 are predominantly involved in the extracellular matrix remodeling and degradation of cartilage collagens and proteoglycans but may affect bone (e.g., MMP3, MMP13) [8,9]

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