The expression of NAMPT in patients with NAFLD has decreased systemically both in serum and within the hepatic tissue, which is regulated by PPARα activation and glucose.469 Meanwhile, the NAMPT is also a target of FoxO transcription factors that control the NAD+ signaling in the regulation of hepatic triglyceride homeostasis.470 Additionally, the hepatic microRNA-34a, which is increased in obesity, reduces NAD+ levels and SIRT1 activity by targeting NAMPT. Here, NAMPT is linked to obesity due to melanocortin 4 receptor deficiency.