The Role of MicroRNAs in Podocytes

Background: MicroRNAs (miRNAs) are small non-coding RNA species approximately 22 nucleotides in length. MicroRNAs repress the translation of target mRNAs or degrade target mRNAs. Studies have shown that miRNAs are implicated in extensive cellular processes and are important in the pathophysiology of many cell types, including podocytes. Summary: The essential role for miRNAs in podocytes was first demonstrated by a targeted deletion of Dicer, the enzyme involved in miRNA biogenesis, in the podocytes of mice; this deletion resulted in proteinuria, podocyte injury, glomerulosclerosis, and renal failure in the mice. Further studies revealed the roles of several miRNAs in the process of podocyte injury, including dedifferentiation, adhesion disruption, and apoptosis. miRNAs also play essential roles in mesangial and endothelial cells, which are two glomerular cell types that interact with podocytes during the process of podocytopathy. Studies have also shown the roles of miRNAs in mediating the therapeutic effect of existing drugs on podocytopathies, including glucocorticoids and ACE inhibitors. Among the miRNAs in podocytes, the miR-30 family appears to be particularly important. Key Messages: miRNAs play critical roles in podocyte homeostasis and podocytopathies. Fully understanding their roles and the molecular mechanisms will improve the diagnosis and treatment of podocytopathies, but further efforts are required to achieve this understanding. (C) 2014 S. Karger AG, Basel