SP1 and Peritoneal Fibrosis: Although there are several mechanisms by which miR-29b might inhibit peritoneal fibrosis, the authors focused on the transcription factor specificity protein 1 (Sp1), which is a putative target of miR-29b that plays an important role in TGF-β1/Smad3 pathway and may be a mechanism by which miR-29b inhibited peritoneal fibrosis [20, 42, 43].