Previous studies have reported that miR-330-5p may be involved in the synaptic loss of hippocampal neuron during Alzheimer's disease pathogenesis [38]; miR-346 negatively regulates Smad3/4 expression by binding to its 3'-UTR, ameliorating the kidney function and histology in diabetic nephropathy [39]. Here, SMAD3 is linked to diabetic kidney disease.