Abstract
Introduction
Osteoarthritis (OA) is a predominant chronic degenerative disease exerting a deep impact on quality of life and healthcare systems. Recent evidences suggest that pyroptosis, a programmed cell death characterized by inflammatory cytokine release, may play a significant role in modulating OA pain. The aim of the study is to investigate the potential role of extracellular vesicles derived from umbilical cord Wharton's jelly (WJ-MSC EVs) in the attenuation of the pyroptotic process on human chondrocytes (hOAC) pre-treated with synovial fluid in a 3D in vitro model.
Method
EVs isolated by tangential filtration of the conditioned medium of WJ-MSCs were characterized for: morphology by TEM, surface markers by WB and size by NTA. Confocal microscopy was used to identify PKH26-labelled EVs and monitor their incorporation into hOACs. The hOACs from surgical waste material of patients undergoing knee replacement, expanded, encapsulated in alginate beads were pre-treated with synovial fluid for 24 h (SF) and subsequently co-incubated with WJ-MSC EVs. We examined viability (CCK-8), metabolic activity (MTT), nitrite production (Griess) activation of the pyroptotis (IF), DNA quantification (PicoGreen) and gene expression levels of extracellular matrix (ECM) components (qPCR). One-way ANOVA analysis was used to compare the groups under exam and data were expressed as mean ± S.D
Result
WJ-MSC EVs increased hOACs viability and metabolic activity. The production of nitrites is significantly decreased compared sample group treated with SF. WJ-MSC EVs inhibited inflammasomes NLRP3 (nucleotide-binding domain, leucine-rich repeat pyrin domain containing 3) activation. The ECM catabolic genes decreased compared to the inflamed SF group for ADAMTS-5 and MMP-1.
Conclusion
Our results supported the potential use of WJ-MSC EVs as a cell-free strategy for OA, overcoming the side effects of cell-therapy. Moreover, WJ-MSC EVs are able to mitigate SF-treated hOACs pyroptotic death, attenuate ECM degradation and oxidative stress counteracting the inflamed status in OA development and progression.
