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Figure 2: Roles of miR-126, miR-155, miR-221, and miR-222 in endothelial cell inflammation and maintenance of vascular integrity. (a) miR-126 regulates EC permeability through inhibition of PI3K and MAPK signaling pathways. miR-126 regulation of SPRED1 also indirectly regulates phosphorylation of cofilin and protein involved in maintenance of EC junctions. (b) Increased miR-126 levels result in a decrease in VCAM-1 levels, providing an anti-inflammatory effect. (c) miR-155 inhibits eNOS synthesis and thereby regulates EC permeability. Additionally, miR-155 inhibits Angiotensin-1 Receptor (AT1R) signaling, decreasing the expression of proinflammatory factors in EC. (d) HIV protein Tat can reduce transcription of miR-221 and miR-222, releasing their blockade on ICAM-1 translation and resulting in an inflammatory response.