IL20

Interleukin-20 (IL-20), also termed IL-20A or cytokine ZCYTO10, is a member of the IL-10 cytokine family. It signals through two heterodimeric receptor complexes: IL-20R1/IL-20R2 and IL-22R1/IL-20R2, activating JAK-STAT pathways, particularly STAT3 phosphorylation. This cytokine regulates epithelial cell functions, keratinocyte proliferation, and osteoclastogenesis, with roles in tissue remodeling and inflammatory responses. Key pathways include JAK-STAT, MAPK, and PI3K/Akt cascades, intersecting with immune regulation and cellular differentiation processes. Dysregulation of IL-20 is implicated in psoriasis, rheumatoid arthritis, and atherosclerosis, driven by its pro-inflammatory effects on endothelial cells and synoviocytes.
Elevated IL-20 expression correlates with psoriasis pathogenesis, where it promotes epidermal hyperplasia and immune cell infiltration. It also contributes to bone resorption in osteoporosis via RANKL-independent osteoclast activation. Therapeutic strategies targeting IL-20 or its receptors include monoclonal antibodies like fletikumab (Phase II) and bispecific agents such as bimekizumab (approved for psoriasis/psoriatic arthritis). Small-molecule inhibitors blocking IL-20R dimerization are under preclinical evaluation. Recent studies highlight its potential role in cancer-associated cachexia and diabetic nephropathy, expanding its clinical relevance beyond classical inflammatory disorders.