IL-33 strongly induces Th2 cytokine production from innate immune cells and T helper 2 (Th2) cells. and can promote the pathogenesis of Th2-related disease such as asthma, atopic dermatitis and anaphylaxis. However, IL-33 has shown various protective effects in cardiovascular diseases such as atherosclerosis, obesity, type 2 diabetes and cardiac remodeling. Thus, the effects of IL-33 are either pro- or anti-inflammatory depending on the disease and the model.
Interleukin-33 (IL33) cytokine is a member of the Interleukin-1 family. It can be classified as an alarmin due to being stored in epithelial cells, endothelial cells and fibroblasts; and is released upon tissue damage to mediate local immune activation.
In mice, IL-33 was found to effect the production of methionine-enkephalin peptides in group 2 innate lymphocytes, in turn promoting the emergence of beige adipocytes, which leads to increased energy expenditure and decreased adiposity.
Administration of IL-33 to mice triggers a range of IL-13–dependent responses, but may also induce production of IL-4 and IL-5, either of which could modulate inflammation in adipose tissue. IL-33 has been shown to protect mice from the metabolic consequences of obesity.