Additionally, obese subjects often display elevated levels of inflammatory mediators, such as tumor necrosis factor-alpha (TNF-α)—a key cytokine in obesity-related inflammation—which activates intracellular signaling cascades like IκB kinase (IKKβ) and c-Jun N-terminal kinase (JNK), both of which contribute to insulin resistance. Here, TNF is linked to obesity due to melanocortin 4 receptor deficiency.