CST3 and kidney disorder: The TGF-β pathway has been associated with the development of a wide array of kidney diseases and may regulate both miRNA-mediated renal injury (38) and the expression of CST3 (cystatin C gene), which is positively controlled by 2 transcription factors: IRF-8 and PU.1 (39, 40), which are both activated by TGF-β/SMAD4 (41, 42), while IRF-8 is negatively regulated by SMAD7.