TGFB1 and obesity due to melanocortin 4 receptor deficiency: When the liver is stimulated by alcohol, obesity, virus, and schistosomiasis hepatitis, furin-like protease in liver immune cells cleaves and activates TGF-β molecules (Shi et al., 2011), allowing the C-terminal of TGF-β molecules to bind to the N-terminal of Latency associated protein (LAP) to form latent TGF-β complexes.