title: Dexamethasone-conjugated polyethylenimine as an efficient gene carrier with an anti-apoptotic effect to cardiomyocytes.
abstract: BACKGROUND
  Dexamethasone is a potent glucocorticoid with anti-inflammatory effects. Dexamethasone can protect ischemic cardiomyocytes from apoptosis. To apply the anti-apoptotic effect of dexamethasone to ischemic disease gene therapy, dexamethasone-conjugated polyethylenimine (PEI-Dexa) was synthesized and evaluated as an anti-apoptotic gene carrier.
  
  
  METHODS
  PEI-Dexa was synthesized with low molecular weight polyethylenimine (PEI2K, 2 kDa). The transfection efficiency and cytotoxicity of PEI-Dexa were evaluated by luciferase assay and the MTT assay. To evaluate the anti-apoptotic effect, PEI-Dexa/DNA complex was transfected into cells and the cells were treated with H(2)O(2). Cell viability and apoptosis level were measured by the MTT assay and caspase-3 assay, respectively.
  
  
  RESULTS
  A transfection assay into H9C2 rat cardiomyocytes showed that PEI-Dexa had the highest transfection efficiency at an 8 : 1 weight ratio (PEI-Dexa/DNA). At this ratio, PEI-Dexa had higher transfection efficiency than high molecular polyethylenimine (PEI25K, 25 kDa) and PEI2K. In addition, the cytotoxicity of PEI-Dexa was lower than that of PEI25K. To evaluate the anti-apoptotic effect, PEI-Dexa/pSV-Luc or PEI2K/pSV-Luc was transfected into H9C2 cells and the cells were treated with H(2)O(2). PEI-Dexa was found to reduce caspase-3 activity and increase cell viability compared to PEI2K. Heme oxygenase-1 (HO-1) can protect ischemic cardiomyocytes from apoptosis. Therefore, pSV-HO-1 was cloned and transfected into H9C2 cells using PEI-Dexa. The cells transfected with PEI-Dexa/pSV-HO-1 complex had lower caspase-3 activity and higher viability than the cells transfected with PEI-Dexa/pSV-Luc complex after the H(2)O(2) treatment.
  
  
  CONCLUSIONS
  PEI-Dexa is an efficient gene carrier with an anti-apoptotic effect and may be useful for anti-apoptotic gene therapy in combination with pSV-HO-1.
authors.affiliation: Department of Bioengineering, College of Engineering, Hanyang University, Seoul, Korea.
authors.forename: Hyunjung
authors.initials: H
authors.lastname: Kim
authors.forename: Hyun Ah
authors.initials: HA
authors.lastname: Kim
authors.forename: Yun Mi
authors.initials: YM
authors.lastname: Bae
authors.forename: Joon Sig
authors.initials: JS
authors.lastname: Choi
authors.forename: Minhyung
authors.initials: M
authors.lastname: Lee
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D003907:Dexamethasone / Q000008:administration & dosage*; D004797:Enzyme-Linked Immunosorbent Assay; D018014:Gene Transfer Techniques; D032383:Myocytes, Cardiac / Q000378:metabolism*; D011094:Polyethyleneimine / Q000737:chemistry* / Q000633:toxicity; D051381:Rats; D014162:Transfection
chemical_list: D000893:Anti-Inflammatory Agents; D003907:Dexamethasone; D011094:Polyethyleneimine; D053148:Caspase 3