We previously found that senescence of cluster of differentiation 4 (CD4) T cells is accelerated in the visceral adipose tissue (VAT) of mice with diet-induced obesity (DIO) due to a high-fat diet (HFD), and that these senescent-associated T cells cause chronic inflammation of visceral adipose tissue through secretion of osteopontin, provoking systemic insulin resistance. Here, SPP1 is linked to obesity due to melanocortin 4 receptor deficiency.