TGF-β can mediate RNA processing through the Smad2/3 pathway, activate the secretion of miR-140-3P and miR-143-3P,[17] reduce the number and activity of islet cells, and ultimately mediate the apoptosis of islet cells, which can lead to type 1 diabetes. The gene discussed is TGFB1; the disease is type 1 diabetes mellitus.