Shinichi Tsumaru1, Hidetoshi Masumoto2, Kenji Minakata3, Masayasu Izuhara4, Kazuhiro Yamazaki1, Tadashi Ikeda1, Koh Ono5, Ryuzo Sakata6, Kenji Minatoya1. 1. Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 2. Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. Electronic address: masumoto@kuhp.kyoto-u.ac.jp. 3. Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Division of Cardiovascular Surgery, Temple University Lewis Katz School of Medicine, Philadelphia, Pa. 4. Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Department of Cardiology, Kishiwada City Hospital, Kishiwada, Japan. 5. Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 6. Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Department of Cardiovascular Surgery, Kobe City Medical Center General Hospital, Kobe, Japan.
Abstract
OBJECTIVE: Recent studies demonstrate that microRNAs show promising potential, including angiogenesis, in therapeutic intervention. MicroRNA-126 (miR-126) is reported to regulate angiogenesis by blocking Sprouty-related EVH1 domain-containing protein 1 (SPRED1), an endogenous inhibitor of vascular endothelial cell growth factor. In this study, we investigated the angiogenic effects of the sustained release of miR-126 loaded with poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) in a murine hindlimb ischemia model. METHODS: We induced mice hindlimb ischemia through femoral artery excision. We randomly assigned the mice to two groups and performed an intramuscular injection of miR-126-loaded PLGA NPs (miR-126) or scrambled miR-loaded PLGA NPs (control) shortly after induction of ischemia. RESULTS: The miR-126 expression levels in the ischemic limb at 3 days after treatment were significantly higher in mice treated with miR-126-loaded PLGA NPs than in those with scrambled miR, indicating the fair efficiency of local miR transduction (control vs miR-126: 0.33 ± 0.12 vs 0.74 ± 0.42; P < .05; n = 6). Laser Doppler perfusion imaging revealed that limb blood flow in mice treated with miR-126-loaded PLGA NPs was significantly higher at 14 days after treatment (sham vs control vs miR-126: 0.62 ± 0.09 vs 0.58 ± 0.05 vs 0.72 ± 0.07; P < .001; n = 12). Immunohistochemical analysis indicated that CD31-positive cell density and α-smooth muscle actin-positive vessel density were significantly higher in miR-126-treated mice (control vs miR-126: 0.33 ± 0.12 vs 0.74 ± 0.42; P < .05; n = 6). SPRED1 messenger RNA expression levels were significantly lower in miR-126-treated mice (control vs miR-126: 1.00 ± 0.05 vs 0.81 ± 0.07; P < .05; n = 6). Western blotting indicated that protein levels of pERK/ERK mediated by SPRED1 were significantly higher in miR-126-treated mice (control vs miR-126: 0.29 ± 0.10 vs 0.54 ± 0.21; P < .05; n = 6). CONCLUSIONS: This study suggests that sustained release of miR-126-loaded PLGA NPs might be an effective method in therapeutic angiogenesis for hindlimb ischemia.
OBJECTIVE: Recent studies demonstrate that microRNAs show promising potential, including angiogenesis, in therapeutic intervention. MicroRNA-126 (miR-126) is reported to regulate angiogenesis by blocking Sprouty-related EVH1 domain-containing protein 1 (SPRED1), an endogenous inhibitor of vascular endothelial cell growth factor. In this study, we investigated the angiogenic effects of the sustained release of miR-126 loaded with poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) in a murine hindlimb ischemia model. METHODS: We induced mice hindlimb ischemia through femoral artery excision. We randomly assigned the mice to two groups and performed an intramuscular injection of miR-126-loaded PLGA NPs (miR-126) or scrambled miR-loaded PLGA NPs (control) shortly after induction of ischemia. RESULTS: The miR-126 expression levels in the ischemic limb at 3 days after treatment were significantly higher in mice treated with miR-126-loaded PLGA NPs than in those with scrambled miR, indicating the fair efficiency of local miR transduction (control vs miR-126: 0.33 ± 0.12 vs 0.74 ± 0.42; P < .05; n = 6). Laser Doppler perfusion imaging revealed that limb blood flow in mice treated with miR-126-loaded PLGA NPs was significantly higher at 14 days after treatment (sham vs control vs miR-126: 0.62 ± 0.09 vs 0.58 ± 0.05 vs 0.72 ± 0.07; P < .001; n = 12). Immunohistochemical analysis indicated that CD31-positive cell density and α-smooth muscle actin-positive vessel density were significantly higher in miR-126-treated mice (control vs miR-126: 0.33 ± 0.12 vs 0.74 ± 0.42; P < .05; n = 6). SPRED1 messenger RNA expression levels were significantly lower in miR-126-treated mice (control vs miR-126: 1.00 ± 0.05 vs 0.81 ± 0.07; P < .05; n = 6). Western blotting indicated that protein levels of pERK/ERK mediated by SPRED1 were significantly higher in miR-126-treated mice (control vs miR-126: 0.29 ± 0.10 vs 0.54 ± 0.21; P < .05; n = 6). CONCLUSIONS: This study suggests that sustained release of miR-126-loaded PLGA NPs might be an effective method in therapeutic angiogenesis for hindlimb ischemia.