MicroRNA-1 (miR-1) has been found overexpressed in ischemic cardiac tissues.Down regulation of miR-1 could relieve apoptosis by the anti-miR-1 antisense oligonucleotides (AMO-1).However, the fact of AMO-1 lacking in vivo myocardial targeting and poor stability greatly limited the therapeutic effect.To increase the therapeutic efficiency and inhibit off-target effects of AMO-1, here we constructed a new gene vector based on dendrigraft poly-L-lysines (DGL) and polyethyleneglycol (PEG), modified with AT1, a functional peptides sequence of Angiotensin Ⅱ Type1, which could be targeted to the AT1 receptor in myocardial cells or tissues, yielding DGL-PEG-AT1.DGL-PEG-AT1 was Loaded with AMO-1 (DGL-PEG-AT1/AMO-1) to deliver the oligonucleotides to myocardial cells or tissues.The result of agarose gel electrophoresis showed that AMO-1 could be effectively encapsulated by DGL-PEG-AT1.DGL-PEG-AT1/ AMO-1 nanoparticles (NPs) were monodispersed, with a mean diameter of 130 ± 6.5nm.MTT results showed that no apparent cytotoxicity was observed when cells were treated with synthesized vectors.The immunofluorescent staining showed that the expression of the Angiotensin Ⅱ Type1 Receptor was obviously increased in cells subjected to hypoxia (1% O2,24h).The targeting abilities to hypoxic primary myocardial cells were evaluated by Bodipy-labelled DGL-PEG-AT1 and the results show that the conjugation of AT1 significantly enhanced the cellular uptake efficiency.The intracellular distribution in vitro were observed by confocal microscopy and flow cytometry,respectively, and DGL-PEG-AT 1/AMO-1-FAM was observed in the cytoplasm and perinuclear area.In addition, after DGL-PEG-AT1/AMO-1 incubated with hypoxic myocardial cells, the miR-1 expression was significantly down-regulated compared with untreated groups.All results demonstrated that DGL-PEG-AT 1/AMO-1 was an efficient gene vector of myocardial cells in vitro.It may be a potential non-viral platform for Myocardial ischemia therapy.