Water-soluble lipopolymer as an efficient carrier for gene delivery to myocardium

Abstract

Water-soluble lipopolymer (WSLP), which consisted of polyethylenimine (PEI, 1800 Da) and cholesterol, was characterized as a gene carrier to smooth muscle cells and myocardium. Acid-base titration showed that WSLP had a proton-buffering effect. The size of WSLP/plasmid DNA (pDNA) complex was around 70 nm. WSLP/pDNA complex was transfected to A7R5 cells, a smooth muscle cell line. WSLP showed the highest transfection at a 40/1 N/P ratio. WSLP has higher transfection efficiency than PEI (1800 and 25 000 Da), SuperFect, and lipofectamine. In addition, WSLP has less cytotoxicity than PEI (25 000 Da), SuperFect, and lipofectamine. Since WSLP has cholesterol moiety, it may utilize cellular cholesterol uptake pathway, in which lowdensity lipoprotein (LDL) is involved. An inhibition study with free cholesterol or low-density lipoprotein (LDL) showed that transfection was inhibited by cholesterol or LDL, suggesting that WSLP/pDNA complex is transfected to the cells through the cholesterol uptake pathway. To evaluate the transfection efficiency to myocardium, WSLP/pDNA complex was injected into the rabbit myocardium. WSLP showed higher transfection than PEI and naked pDNA. WSLP expressed the transgene for more than 2 weeks. In conclusion, WSLP is an efficient carrier for local gene transfection to myocardium, and useful in in vivo gene therapy.

Reducible poly(amido ethylenediamine) for hypoxia-inducible VEGF delivery

“…Previous work in our lab using water soluble lipopolymer (WSLP) produced significantly higher gene expression than naked pDNA and bPEI/pDNA in the same model [36]. WSLP also mediated higher transgene expression in ischemic rabbit myocardium as apposed to healthy myocardium using the hypoxia inducible pEpo-SV-VEGF plasmid [23].…”

“…Previous work in our lab was performed by injecting 200 μg pDNA complexed with WSLP into rabbit myocardium [23,36]. We initially decided to perform dose response injections with our SS-PAED/RTP-VEGF system starting at 100 μg RTP-VEGF and then increasing the dose until VEGF expression was apparent.…”

Polymeric gene delivery of ischemia-inducible VEGF significantly attenuates infarct size and apoptosis following myocardial infarct

“…The use of this polymer has been used to deliver genes to several different cancers, myocardium and corpus cavernosum. [45][46][47][48][49] In summary, we have demonstrated that ischemiainducible VEGF gene therapy improves the efficacy of VEGF gene therapy for myocardial infarction through decreased apoptosis and increased angiogenesis.…”

“…44,45 The WSLP gene carrier forms self-assembling lipopolymer/DNA complexes with the therapeutic gene. The multifunctional characteristics of these novel polymers include DNA condensation, protection of DNA integrity, cell membrane adhesion and endosomal disruption capabilities with minimal toxicity.…”

“…12,44,45 In vitro analysis H9c2 and A7R5 cells were grown in 24-well plates with 500 ml complete media (DMEM+10% FBS). At 50% In vitro viability under hypoxia was accomplished by transfecting H9c2 or A7R5 cells with 1 mg of WSLP/ pRTP801-VEGF at similar N/P ratios as described above.…”