Cartilage Homeostasis and Osteoarthritis

Abstract

Healthy limb joints are important for maintaining health and attaining longevity. Endochondral ossification (the replacement of cartilage with bone, occurring during skeletal development) is essential for bone formation, especially in long-axis bones. In contrast to endochondral ossification, chondrocyte populations in articular cartilage persist and maintain joint tissue into adulthood. Articular cartilage, a connective tissue consisting of chondrocytes and their surrounding extracellular matrices, plays an essential role in the mechanical cushioning of joints in postnatal locomotion. Osteoarthritis (OA) pathology relates to disruptions in the balance between anabolic and catabolic signals, that is, the loss of chondrocyte homeostasis due to aging or overuse of cartilages. The onset of OA increases with age, shortening a person’s healthy life expectancy. Although many people with OA experience pain, the mainstay of treatment is symptomatic therapy, and no fundamental treatment has yet been established. To establish regenerative or preventative therapies for cartilage diseases, further understanding of the mechanisms of cartilage development, morphosis, and homeostasis is required. In this review, we describe the general development of cartilage and OA pathology, followed by a discussion on anabolic and catabolic signals in cartilage homeostasis, mainly microRNAs.

Dihydrocaffeic acid improves IL-1β-induced inflammation and cartilage degradation via inhibiting NF-κB and MAPK signalling pathways

“…Cartilage degeneration includes the imbalance of anabolism and catabolism in chondrocytes, such as the weakening of anabolism and/or enhancement of catabolism, which will lead to the increased degradation of ECM on the surface of cartilage and contribute to cartilage deterioration and OA formation. 52,53 MMPs, such as MMP1, MMP3, and MMP13, are important catabolic enzymes, the overexpression of which target collagen II and aggrecan for degradation. [54][55][56] However, the most important enzymes of anabolism are collagen II and aggrecan, which could maintain the physiological structure of ECM.…”

Siraitia grosvenorii Residual Extract Inhibits Inflammation in RAW264.7 Macrophages and Attenuates Osteoarthritis Progression in a Rat Model

“…Cartilage is composed of chondrocytes and ECM. SOX9 plays an important role in chondrocyte differentiation and chondrogenesis, and type II collagen (COL2A1) and proteoglycans such as aggrecan are major components of the ECM [ 40 ]. MMPs are enzymes responsible for ECM degradation and are expressed in the joint tissues of patients with OA.…”

Autophagy inhibition mediated by intrauterinemiR‐1912‐3p/CTSDprogramming participated in the susceptibility to osteoarthritis induced by prenatal dexamethasone exposure in male adult offspring rats

“…Collagen and aggrecan make up the main components of the extracellular matrix, which are the structural basis for maintaining articular cartilage's support and lubrication function. Increased catabolism is the key mechanism in the development and progression of adult osteoarthritis 53,54 . MMP13 is an important degradation enzyme of the cartilage matrix, which has a stronger effect on hydrolyzing collagen fibers than other MMPs 55 .…”