title: Suppression of NF-kappaB p65 expression attenuates delayed xenograft rejection.
abstract: BACKGROUND
  Delayed xenograft rejection (DXR) involves type II vascular endothelial cell (VEC) activation including upregulation of pro-inflammatory genes, which contributes to infiltration into the graft and a complex process of cytokine production. Approaches to prevent DXR have shown limited success. In this study, we modified heart donors using siRNA in an attempt to attenuate DXR and to improve xenograft survival in the mouse-to-rat heterotopic heart transplant model.
  
  
  METHODS
  siRNA technology was used to inhibit NF-kappaB p65 gene expression in vivo in mice. After the donor was transfected with siRNA, the effects of NF-kappaB siRNA on DXR and expression of NF-kappaB and pro-inflammatory genes were evaluated in a concordant mouse-to-rat cardiac xenograft model.
  
  
  RESULTS
  Treatment of NF-kappaB siRNA prolonged median heart graft survival time in the recipient rats from 1.7 days in a PBS control group to 5.4 days in the NF-kappaB siRNA-treated group (P < 0.05). Compared with normal mouse hearts, the NF-kappaB p65 mRNA relative levels following siRNA injection in the donors decreased significantly (approximately 70% reduction) in grafts harvested 12 h after transplantation. The mRNA levels of VCAM-1, ICAM-1, and interleukin-1 displayed a similar reduction. Histological evaluation using light and electron microscopy showed that damage of endothelial cells after NF-kappaB siRNA treament occured at a later time.
  
  
  CONCLUSIONS
  Transfection of NF-kappaB p65 siRNA in donor animals can delay the emergence of DXR. This treatment may be used as part of strategies to minimize the complex and multi-faceted rejection responses in vascularized xenografts.
authors.affiliation: Department of Cardiovascular Surgery of the First affiliated Hospital, Institute for Cardiovascular Science of Soochow University, Suzhou, Jiangsu 215006, China. shenjs2010@yahoo.com.cn
authors.forename: Zhenya
authors.initials: Z
authors.lastname: Shen
authors.forename: Wenxue
authors.initials: W
authors.lastname: Ye
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Ten
mesh_terms: D000818:Animals; D015316:Genetic Therapy / Q000379:methods*; D006084:Graft Rejection / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D006085:Graft Survival / Q000276:immunology; D016027:Heart Transplantation / Q000009:adverse effects / Q000276:immunology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D007375:Interleukin-1 / Q000235:genetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D051996:Transcription Factor RelA / Q000235:genetics* / Q000276:immunology; D014162:Transfection; D014183:Transplantation, Heterologous / Q000009:adverse effects / Q000276:immunology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics
chemical_list: D007375:Interleukin-1; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051996:Transcription Factor RelA; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1