Li et al. found that the exosomes derived from human umbilical cord MSCs (hucMSC) ameliorate liver fibrosis by inhibiting both the epithelial-mesenchymal transition of hepatocytes and collagen production, significantly restore the serum aspartate aminotransferase activity and inactivate the TGF-β1/Smad2 signaling pathway by decreasing collagen type I/III and TGF-β1 and the phosphorylation of Smad2 [30]. Here, SMAD2 is linked to Hepatic fibrosis.