TNF and obesity due to melanocortin 4 receptor deficiency: LCN2 participated in obesity and its metabolic complications such as T2DM, and cardiovascular diseases, which may relate to the activation of LCN2 signaling (such as TNF-α/NLRP3/LCN2) inducing mitochondrial dysfunction, oxidative stress, insulin resistance, and macrophage activation in adipocytes [34–36].