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 posttranscriptional
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.
Results: 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 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.