MicroRNA signature and function in retinal neovascularization

Figure 1 Schematic representation of microRNA (miRNA) biogenesis. miRNA genes are transcribed into large pre-miRNA (capital R) that are cleaved by a protein complex containing the endonuclease Drosha into shorter pre-miRNAs. The latter are then transported to the cytoplasm by exportin-5. A complex containing the endonuclease, Dicer, then cleaves the loop portion of the pre-miRNA (capital R) to form a short duplex molecule that is unwound, and the single-stranded mature mirNA is then passed to Argonaute to from a functional mature, approximately 22 nucleotide, miRNA that inhibit translation after base-pairing with the 3’ UTR of the miRNA (capital R) target.

Figure 2 Overview of major angiogenic and antiangiogenic miRNAs and their targets in promoting or suppressing retinal neovascularization. VEGF: Vascular endothelial growth factor; IGFs: Insulin-like growth factors; HIF-1α: Hypoxia-inducible factor 1α; bFGF: Basic fibroblast growth factor; PDGF: Platelet derived growth factor; IL-8: Interleukin 8; MMP: Matrix metalloproteinase; ICAM-1: Intercellular adhesion molecule-1; TNF-α: Tumour necrosis factor-alpha; MAPK: Mitogen-activated protein kinase.