TNF and metabolic dysfunction-associated steatotic liver disease: On the other hand, several abnormalities intrinsic to NAFLD impair insulin receptor signaling, especially FFAs, tumor necrosis factor-alpha (TNF-α), nuclear factor kappa B (NF-κB), ceramide, Jun N-terminal kinase 1 (JNK1), suppressors of cytokine signaling (SOCS) and cytochrome CYP2E1.