TNF and obesity due to melanocortin 4 receptor deficiency: During obesity, significantly increased macrophages accumulate in adipose tissue and form the so-called ‘crown-like structures' (CLSs) around the dead adipocytes.1, 2 Those macrophages exhibit M1 phenotype and produce various types of inflammatory cytokines, such as TNF-α, resulting in the propagation of obesity-related inflammation and the development of metabolic disorders, such as insulin resistance.3, 4, 5