A human in vitro 3D neo-cartilage model to explore the response of OA risk genes to hyper-physiological mechanical stress. Issue 1 (March 2022)

• Record Type: Journal Article
• Authors: Timmermans, Ritchie G.M.; Bloks, Niek G.C.; Tuerlings, Margo; van Hoolwerff, Marcella; Nelissen, Rob G.H.H.; van der Wal, Robert J.P.; van der Kraan, Peter M.; Blom, Arjen B.; van den Bosch, Martijn H.J.; Ramos, Yolande F.M.; Meulenbelt, Ingrid
• Is Part Of: Osteoarthritis and cartilage open. Volume 4:Issue 1(2022)
• Publication Date: 2022-03
• Subjects: Mechanical stress -- Human neo-cartilage -- Osteoarthritis -- OA risk genes; Osteoarthritis -- Periodicals; Cartilage -- Periodicals; 616.7223005
• DOI: 10.1016/j.ocarto.2021.100231
• Languages: English
• ISSNs: 2665-9131

Abstract

Abstract: Objective: Due to the complexity and heterogeneity of osteoarthritis (OA) pathophysiology, studying the interaction between intrinsic molecular changes in chondrocytes after hyper-physiological mechanical stress (MS) and aberrant signalling of OA risk genes remains a challenge. In this study we set out to set up an in vitro 3D neo cartilage pellet model that enables us to explore the responses of OA risk genes to hyper-physiological MS. Design: Human primary chondrocyte neo-cartilage pellets were exposed for 2 days to 2 ​× ​10 ​min of hyper-physiological dynamic MS attained by a 20% strain and a frequency of 5 ​Hz. In order to assess cartilage damage, sulphated glycosaminoglycan (sGAG) content in the neo-cartilage was quantified using Alcian blue staining and a dimethyl methylene blue (DMMB) assay, while cleavage of aggrecan was visualized by immunohistochemical staining of aggrecan neo-epitope NITEGE. In addition, changes in expression levels of catabolic, anabolic and hypertrophic genes, and of three OA risk genes; IL11, MGP and TGFA were determined. Results: Hyper-physiological MS induced cartilage damage, as reflected by decreased sGAG content. mRNA levels of aggrecanase ADAMTS5 were increased, while hypertrophic gene RUNX2 was downregulated. MS increased expression of pro-apoptotic marker NOXA . Furthermore, 20% MS led to increased expression of all three OA risk genes IL11, MGP and TGFA . Conclusions: We established a human in vitro model in which hyper-physiological MS induced cartilage damage and catabolic signalling. Next, we demonstrated its usage to study OA risk genes and their response to the mechanical aspects of OA pathophysiology.