TNF and obesity due to melanocortin 4 receptor deficiency: For instance, some clinical observations have shown that OCN is inversely correlated with systemic inflammatory markers (e.g., IL-6 and CRP) in patients with diabetes, obesity, or metabolic syndrome [30,31,32,33,34,35,36], while OCN treatment could substantially downregulate inflammatory related genes and transcription factors in an obese mice model [37] and in TNFα-stimulated primary cultured adipocytes [37,38].