Background: Diabetes Mellitus is a multifactorial disease encompassing various pathogenic
pathways. To avoid morbidity and mortality related to diabetic complications, early detection of
disease complications as well as targeted therapeutic strategies, are essential.
Introduction: MicroRNAs (miRs) are short non-coding RNA molecules that regulate eukaryotic
post-transcriptional gene expression. MicroRNA-21 has diverse gene regulatory functions and plays a
significant role in various complications of Type 2 diabetes mellitus (T2DM).
Methods: The study included electronic database searches on Pubmed, Embase, and Web of Science
with the search items MicroRNA21 and each of the diabetic complications. The search was carried
out up to November, 2019.
Result: MicroRNA-21 modulates diabetic cardiomyopathy by affecting vascular smooth muscle cell
proliferation and apoptosis, cardiac cell growth and death, and cardiac fibroblast functions. At the
renal tubules, miR-21 can regulate the mesangial expansion, interstitial fibrosis, macrophage
infiltration, podocyte loss, albuminuria and fibrotic and inflammatory gene expression related to
diabetic nephropathy. Overexpression of miR-21 has been seen to play a pivotal role in the
pathogenesis of diabetic retinopathy by contributing to diabetes-induced endothelial dysfunction as
well as the low-grade inflammation.
Conclusion: Considering the raised levels of miR-21 in various diabetic complications, it may prove
to be a candidate biomarker for diabetic complications. Further, miR-21 antagonists have shown great
potential in the treatment of diabetic cardiomyopathy, diabetic nephropathy, diabetic retinopathy, and
diabetic neuropathy related complications in the future. The current review is the first of its kind
encompassing the roles miR-21 plays in various diabetic complications, with a critical discussion of
its future potential role as a biomarker and therapeutic target.