INS and obesity due to melanocortin 4 receptor deficiency: We have previously demonstrated that mice lacking endogenous OGG1 (Ogg1–/–) are prone to diet-induced obesity (DIO) and its sequelae, including insulin resistance, ectopic lipid accumulation in liver and skeletal muscle, gut dysbiosis, and chronic inflammation (Sampath et al., 2012b; Vartanian et al., 2017; Simon et al., 2020).