In Vitro Evaluation of the Anti-Inflammatory Effect of KMUP-1 and In Vivo Analysis of Its Therapeutic Potential in Osteoarthritis.

Shang-En Huang,Bin-Nan Wu,Erna Sulistyowati,Jong-Hau Hsu,Jwu-Lai Yeh,Zen-Kong Dai,Yu-Ying Chao

doi:10.3390/biomedicines9060615

Abstract

Osteoarthritis is a degenerative arthropathy that is mainly characterized by dysregulation of inflammatory responses. KMUP-1, a derived chemical synthetic of xanthine, has been shown to have anti-inflammatory and antioxidant properties. Here, we aimed to investigate the in vitro anti-inflammatory and in vivo anti-osteoarthritis effects of KMUP-1. Protein and gene expressions of inflammation markers were determined by ELISA, Western blotting and microarray, respectively. RAW264.7 mouse macrophages were cultured and pretreated with KMUP-1 (1, 5, 10 μM). The productions of TNF-α, IL-6, MMP-2 and MMP- 9 were reduced by KMUP-1 pretreatment in LPS-induced inflammation of RAW264.7 cells. The expressions of iNOS, TNF-α, COX-2, MMP-2 and MMP-9 were also inhibited by KMUP-1 pretreatment. The gene expression levels of TNF and COX families were also downregulated. In addition, KMUP-1 suppressed the activations of ERK, JNK and p38 as well as phosphorylation of IκBα/NF-κB signaling pathways. Furthermore, SIRT1 inhibitor attenuated the inhibitory effect of KMUP-1 in LPS-induced NF-κB activation. In vivo study showed that KMUP-1 reduced mechanical hyperalgesia in monoiodoacetic acid (MIA)-induced rats OA. Additionally, KMUP-1 pretreatment reduced the serum levels of TNF-α and IL-6 in MIA-injected rats. Moreover, macroscopic and histological observation showed that KMUP-1 reduced articular cartilage erosion in rats. Our results demonstrated that KMUP-1 inhibited the inflammatory responses and restored SIRT1 in vitro, alleviated joint-related pain and cartilage destruction in vivo. Taken together, KMUP-1 has the potential to improve MIA-induced articular cartilage degradation by inhibiting the levels and expression of inflammatory mediators suggesting that KMUP-1 might be a potential therapeutic agent for OA.

Highlights

Osteoarthritis (OA) has long been defined as a degenerative disease characterized by continuously articular cartilage damage, formation of osteophyte, and subchondral bones alteration, resulting in devastating chronic pain in affected individuals [1]
Initiation of the NF-κB signaling increases the production of nitric oxide (NO), cyclooxygenase-2 (COX-2) and matrix metalloproteinases (MMPs), which account for the articular cartilage breakdown [4,5,6]
Various concentrations of KMUP-1 increased cells viability in LPS-induced cytotoxicity in RAW264.7 cells. The inflammatory markers, such as NO, inducible nitric oxide synthase (iNOS), Tumor necrosis factor-α (TNF-α), COX-2, MMP-2, and MMP-9 were reduced by various concentrations of KMUP-1 pretreatment

Summary

Introduction

Osteoarthritis (OA) has long been defined as a degenerative disease characterized by continuously articular cartilage damage, formation of osteophyte, and subchondral bones alteration, resulting in devastating chronic pain in affected individuals [1]. Biomedicines 2021, 9, 615 cytokines have a primarily destructive impact on articular cartilage. It is a multilevel im-pact that involves the induction of aging and apoptosis of chondrocytes, and a decrease in the synthesis of the key components of extracellular matrix, such as proteo-glycans, and type II collagen [2]. There are several factors such as aging, genetic, and mechanical-associated factors that are involved in the pathogenesis of OA. These factors lead to synovitis, apoptosis, and cartilage destruction [4]

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