Cytokines
Signalling proteins such as IL-1β and TNF-α that drive joint inflammation and cartilage matrix breakdown.
Cytokines are secreted signalling proteins that coordinate the inflammatory component of osteoarthritis, with interleukin-1 beta, tumour necrosis factor alpha and interleukin-6 among the most important [1]. In the joint they are produced by chondrocytes, synoviocytes and infiltrating immune cells, and adipose-derived sources help link obesity to joint inflammation [1]. Acting on chondrocytes, they drive the expression of matrix metalloproteinases and aggrecanases while suppressing collagen and proteoglycan synthesis, shifting the tissue toward degradation [1]. They also raise reactive oxygen species, so cytokine signalling and oxidative stress amplify one another [2].
Much of this activity is transmitted through nuclear factor kappa B, which propagates the inflammatory programme and pushes chondrocytes toward hypertrophic and senescent states [3]. Because they sit upstream of so much matrix damage, cytokines are studied both as biomarkers and as therapeutic targets [2]. Their controlled use in the laboratory also provides a way to model osteoarthritic stress, which is how they feature in Jessica's experimental work [3].
References
- [1] T. Wang and C. He, "Pro-inflammatory cytokines: The link between obesity and osteoarthritis," Cytokine Growth Factor Rev., vol. 44, pp. 38–50, 2018.
- [2] M. Y. Ansari, N. Ahmad, and T. M. Haqqi, "Oxidative stress and inflammation in osteoarthritis pathogenesis: Role of polyphenols," Biomed. Pharmacother., vol. 129, art. no. 110452, 2020.
- [3] E. Horváth, Á. Sólyom, J. Székely, E. E. Nagy, and H. Popoviciu, "Inflammatory and metabolic signaling interfaces of the hypertrophic and senescent chondrocyte phenotypes associated with osteoarthritis," Int. J. Mol. Sci., vol. 24, no. 22, art. no. 16468, 2023.