For example, β-HB increases the histone acetylation of genes that encode resistance factors against oxidative stress;145 (3) activates GPR109A, which is widely expressed in various types of immune cells and exerts anti-inflammatory effects in many diseases, including obesity, inflammatory bowel disease, and cancer;109,146 (4) inhibits NLRP3,147 a key inflammasome that activates pro-inflammatory cytokines, such as IL-1β and IL-18, which closely correlate with obesity and T2DM pathogenesis.148. The gene discussed is HCAR2; the disease is obesity due to melanocortin 4 receptor deficiency.