title: Local gene silencing of monocyte chemoattractant protein-1 prevents vulnerable plaque disruption in apolipoprotein E-knockout mice.
abstract: Monocyte chemoattractant protein-1 (MCP-1), a CC chemokine (CCL2), has been demonstrated to play important roles in atherosclerosis and becoming an important therapeutic target for atherosclerosis. The present study was undertaken to test the hypothesis that local RNAi of MCP-1 by site-specific delivery of adenovirus-mediated small hairpin RNA (shRNA) may enhance plaque stability and prevent plaque disruption in ApoE-/- mice. We designed an adenovirus-mediated shRNA against mouse MCP-1 (rAd5-MCP-1-shRNA). Male apolipoprotein E-knockout (ApoE-/-) mice (n = 120) were fed a high-fat diet and vulnerable plaques were induced by perivascular placement of constrictive collars around the carotid artery, intraperitoneal injection of lipopolysaccharide and stress stimulation. Mice were randomly divided into RNA interference (Ad-MCP-1i) group receiving local treatment of rAd5-MCP-1-shRNA suspension, Ad-EGFP group receiving treatment of rAd5-mediated negative shRNA and mock group receiving treatment of saline. Two weeks after treatment, plaque disruption rates were significantly lower in the Ad-MCP-1i group than in the Ad-EGFP group (13.3% vs. 60.0%, P = 0.01), and local MCP-1 expression was significantly inhibited in the Ad-MCP-1i group confirmed by immunostaining, qRT-PCR and western blot (P<0.001). Compared with the Ad-EGFP group, carotid plaques in the Ad-MCP-1i group showed increased levels of collagen and smooth muscle cells, and decreased levels of lipid and macrophages. The expression of inflammatory cytokines and activities of matrix metalloproteinases (MMPs) were lower in the Ad-MCP-1i group than in the Ad-EGFP group. In conclusion, site-specific delivery of adenoviral-mediated shRNA targeting mouse MCP-1 downregulated MCP-1 expression, turned a vulnerable plaque into a more stable plaque phenotype and prevented plaque disruption. A marked suppression of the local inflammatory cytokine expression may be the central mechanism involved.
authors.affiliation: Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Qilu Hospital, Shandong University, Jinan, Shandong, China.
authors.forename: Xiao Ling
authors.initials: XL
authors.lastname: Liu
authors.forename: Peng Fei
authors.initials: PF
authors.lastname: Zhang
authors.forename: Shi Fang
authors.initials: SF
authors.lastname: Ding
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.forename: Yu Xia
authors.initials: YX
authors.lastname: Zhao
authors.forename: Mei
authors.initials: M
authors.lastname: Ni
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D054058:Acute Coronary Syndrome / Q000517:prevention & control*; D000818:Animals; D001057:Apolipoproteins E / Q000235:genetics; D015153:Blotting, Western; D016022:Case-Control Studies; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D058226:Plaque, Atherosclerotic / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D001057:Apolipoproteins E; D018932:Chemokine CCL2; D016207:Cytokines; D034741:RNA, Small Interfering; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D020782:Matrix Metalloproteinases