Heme oxygenase 1 gene transfer prevents CD95/Fas ligand-mediated apoptosis and improves liver allograft survival via carbon monoxide signaling pathway.
Apoptosis via the CD95/FasL (CD95L) pathway plays an important role in allograft rejection. Heme oxygenase 1 (HO-1), a stress-responsive cytoprotective molecule, may be essential in preventing graft rejection. We used Ad-HO-1 gene transfer to analyze HO-1-mediated effects in a rat allogeneic orthotopic liver transplantation (OLT) model. The cytotoxicity to Fas-bearing YAC-1 target cells and frequency of terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling-positive (TUNEL(+)) cells in vitro were diminished in Ad-CD95L + Ad-HO-1-transfected cells, as compared with Ad-CD95L + Ad-beta-gal controls (p < 0.001). AdHO-1 gene transfer prevented <10-day rejection of dark agouti (DA) livers in Lewis (LEW) rats (survival >32 days), and diminished apoptosis. Unlike Ad-beta-gal OLTs, which showed signs of severe acute rejection, OLTs in the Ad-HO-1 group exhibited mild to moderate rejection and improved function. These beneficial effects were abrogated after adjunctive treatment with tin protoporphyrin (SnPP), an HO-1 antagonist. Intragraft expression of HO-1 and antiapoptotic gene products (Bcl-xl/Bag-1) was enhanced in Ad-HO-1-transduced OLTs, in association with selectively depressed expression of helper T cell type 1 cytokines (interleukin 2 and interferon gamma), as compared with Ad-beta-gal controls. To deliver CO, one of the downstream HO-1 mediators, allogeneic OLT recipients were exposed to methylene chloride. Such treatment prolonged survival to >47 days, diminished apoptosis, and preserved hepatic architecture/function. Thus, Ad-HO-1 gene transfer prevents CD95/FasL-mediated apoptosis, and significantly prolongs allogeneic OLT survival via a downstream HO-1-CO signaling pathway.
Dumont-UCLA Transplant Center, Division of Liver and Pancreas Transplantation, Department of Surgery, UCLA School of Medicine, Los Angeles, CA 90095, USA.
Bibo
B
Ke
Roland
R
Buelow
Xiu-Da
XD
Shen
Judy
J
Melinek
Farin
F
Amersi
Feng
F
Gao
Thomas
T
Ritter
Hans-Dieter
HD
Volk
Ronald W
RW
Busuttil
Jerzy W
JW
Kupiec-Weglinski
D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D053222:Fas Ligand Protein; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D006084:Graft Rejection / Q000517:prevention & control*; D006367:HeLa Cells; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics* / Q000502:physiology; D051547:Heme Oxygenase-1; D006801:Humans; D020287:In Situ Nick-End Labeling; D008099:Liver / Q000378:metabolism; D016031:Liver Transplantation / Q000502:physiology; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors* / Q000502:physiology; D008565:Membrane Proteins; D051381:Rats; D011917:Rats, Inbred Lew; D015398:Signal Transduction; D015854:Up-Regulation; D019014:fas Receptor / Q000502:physiology
C505661:FASLG protein, human; D053222:Fas Ligand Protein; C505662:Faslg protein, rat; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D019014:fas Receptor; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1