Although the expression of miR-21 is downregulated in early DKD (Zhang et al., 2009b), it is upregulated in TECs and MCs stimulated by TGF-β1 or HG and in the renal biopsies of DKD patients (Zhong et al., 2011; Wang et al., 2013; Zhong et al., 2013; Wang et al., 2014; Lai et al., 2015; Mcclelland et al., 2015; Kölling et al., 2017; Chen et al., 2018). The gene discussed is TGFB1; the disease is diabetic kidney disease.