Abstract 16590: MiR-30e Reduces Plaque Burden in Atherogenic APOE-/- by Regulating VSMC Plasticity
Objective: Vascular smooth muscle cells (VSMCs) are implicated in the pathogenesis of proliferative vascular diseases like atherosclerosis. Identification of pathways that mediate dysfunction of these cells will identify new therapeutic targets.
Method and Results: In Situ Hybridization in mouse aortic (Ao) tissue showed that miR-30e is abundantly expressed in medial VSMCs. Using microrarrays and qPCR, we found that in mouse AoVSMCs, miR-30e lentiviral delivery increased (p<.05) gene and protein expression of SM lineage markers (SM22α, Cnn1, Vcl) and decreased (p<.05) chemokines (Cxcl1, Cxcl5, Cxcl15) - hallmarks of VSMC differentiation. Consistent with the differentiated phenotype, Electron Microscopy of VSMCs treated with miR-30e showed that the density of intracellular organelles, especially mitochondria was less (44% down; p=.003) in cells treated with miR-30e relative to the Scrambled (Scr) oligo group. Transfection of AoVSMCs from SM22α-LacZ mice with 10nM 2’F premiR-30e oligos or a blank control for 24hrs showed significant induction of SM22α and CNN1 transcripts (p=.03), and SM22α promoter activity (p=.0001), as measured by qPCR and β-Galactosidase assay, respectively. In young 6mo old APOE-/- mice on a HF diet, given a single dose (8.1x108 particles) of miR-30e (n=10) or a scr control (n=10) lentivirus via tail vein injection, thoracic Ao fat deposit was reduced as measured by Oil Red staining. Cholesterol and LDL levels were decreased significantly, by 40% and 50% respectively. Hepatic Hmgcr protein levels were reduced by 58% (p=.048). Using double luciferase assay in 293Ts, we identified Hmgcr as a novel target for miR-30e indicated by reduction (p<.05) of Firefly/Renilla luminescence. In 13.5 mo APOE mice on HF, injected with miR-30e (n=5) or scr oligo (n=5) lentivirus, miR-30e treatment caused significant plaque reduction in the thoracic aortas in the old APOE-/- mice compared to the control group. In the carotids, miR-30e reduced plaque not only significantly (p<.05) but to a level less than that of the age-matched group of APOE-/- mice on normal chow.
Conclusion: MiR-30e opposes the synthetic VSMC phenotype and promotes differentiation by activating the SM22a promoter. In atherogenic APOE-/- mice, miR-30e reduces plaque burden.
- © 2012 by American Heart Association, Inc.