Mesenchymal stem cell-derived microRNAs: Key immunomodulators to prevent ocular tissue degeneration

MicroRNAs (miRNAs) are small non-coding RNAs of 20-22 nucleotides in length. They have been identified as major regulators in the secretome of mesenchymal stem cells (MSCs) including adipose tissue, bone marrow, Wharton's jelly, and dental pulp. These MSCs and their secretome with specific miRNAs are known modulators of the immune response, angiogenesis, inflammation, and apoptosis. In this review, the application of MSC-derived miRNAs in treating several ocular conditions including dry eye, glaucoma, and retinal degenerative diseases has been compiled. In addition, the emerging role of MSC-derived extracellular vesicles carrying miRNAs as a major cargo, regulating the target cells in the human eye has been reviewed. Finally, the bioengineering of nanovesicles with specific MSC-derived miRNAs as novel drug therapy has been discussed.