USP4 and pulmonary fibrosis: MiR-148a-3p, part of the miR-148/-152 family, plays a key role in regulating fibrosis.54 MiR-148a inhibits liver fibrosis by targeting USP4,55 while miR-148a-3p suppresses alcoholic liver fibrosis by regulating ERBB3.56 In gastric cancer cells, the SMAD2 gene is a direct target of miR-148a.57 Notably, miR-148a-3p, delivered via hucMSC-derived extracellular vesicles, has been shown to target Hsp90b1 and prevent silica-induced pulmonary fibrosis.58 Based on these findings, we proposed that the delivery of miR-148a-3p to LECs by hucMSC-Exo may contribute to its anti-fibrotic effects.