Metabolic tissue-resident CD8+ T cells: A key player in obesity-related diseases.

Obesity-induced low-grade chronic inflammation in the metabolic tissues, such as adipose tissue (AT) and liver tissue, in individuals with obesity is a major etiological factor for several diseases, such as insulin resistance, type 2 diabetes, fatty liver disease, atherosclerosis and cardiovascular problems, as well as cancer and autoimmune diseases. Previous studies have revealed that tissue-resident macrophages play a crucial role in this process. However, the mechanisms responsible for recruiting and activating macrophages and initiating chronic inflammation in the metabolic tissues have not yet been clearly elucidated. In the most recent decade, there has been a growing emphasis on the critical role of the adaptive CD8+ T cells in obesity-induced chronic inflammation and related metabolic diseases. In this review, we will summarize the relevant studies in both mice and human regarding the role of metabolic tissue-resident CD8+ T cells in obesity-related inflammation and diseases, as well as the possible mechanisms underlying the regulation of CD8+ T cell recruitment, activation and function in the metabolic tissues, and discuss their potential as therapeutic targets for obesity-related diseases.