Heterotopic ossification (HO), the pathologic formation of extraskeletal bone, can be disabling and lethal. However, the underlying molecular mechanisms were largely unknown. The present study aimed to clarify the involvement of secreted protein acidic and rich in cysteine (SPARC) and the underlying mechanism in rat model of HO. The mechanistic investigation on roles of SPARC in HO was examined through gain- and loss-of-function approaches of SPARC, with alkaline-phosphatase (ALP) activity, mineralized nodules, and osteocalcin (OCN) content measured. To further confirm the regulatory role of SPARC, levels of mitogen-activated protein kinase (MAPK) signaling pathways-related proteins (extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), p38, nuclear factor κ-B (NF-κB), and IkB kinase β (IKKβ)) were determined. Bone marrow mesenchymal stem cells were treated with pathway inhibitor to investigate the relationship among SPARC, MAPK signaling pathway, and HO. The results suggested that SPARC expression was up-regulated in Achilles tendon tissues of HO rats. Silencing of SPARC could decrease phosphorylation of ERK, JNK, p38, NF-κB, and IKKβ. Additionally, silencing of SPARC or inhibition of MAPK signaling pathway could reduce the ALP activity, the number of mineralized nodules, and OCN content, thus impeding HO. To sum up, our study identifies the inhibitory role of SPARC gene silencing in HO via the MAPK signaling pathway, suggesting SPARC presents a potential target for HO therapy.
Li (2019) Paeonol prevents IL-1β-induced inflammatory response and degradation of type II collagen in human primary chondrocytes, Artificial ABSTRACT Osteoarthritis (OA) is a common joint disease for which a safe and reliable treatment has yet to be developed. Here, we demonstrated the potential benefit of treatment with paeonol, a derivative of Paeonia suffruticosa, in the treatment and prevention of OA. Chondrogenic cell line ATDC5 cells were cultured with IL-1b and the effects of paeonol were assessed through qRT-PCR, western blot analysis, MTT, ELISA, and NF-jB luciferase reporter gene assay. Our findings demonstrate a novel ability of paeonol to inhibit numerous factors of OA, including expressions of IL-6, TNF-a, NOX2, PTGS2, NUCB2/nesfatin-1, ICAM-1, VCAM-1, MMP-3/13, degradation of type II collagen, and NF-jB activation through the rescue of IjBa. Additionally, we assessed the effects of paeonol on cell viability to confirm its safety. These findings implicate a valuable potential role of paeonol in the treatment and prevention of OA.
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