TLR4 and obesity due to melanocortin 4 receptor deficiency: Notably, berberine can promote the differentiation of brown preadipocytes via the AMPK-PRDM16 axis [20], inhibit TLR4/TNF-α-mediated inflammatory responses, and reduce the expression of iNOS and COX-2 [28,45,46], thereby enhancing thermogenesis and alleviating obesity through improved inflammation.