title: Heme oxygenase 1 mediates the immunomodulatory and antiapoptotic effects of interleukin 13 gene therapy in vivo and in vitro.
abstract: This study analyzes mechanisms by which interleukin 13 (IL-13) affects "infectious tolerance" in rat recipients of cardiac allografts, with emphasis on interactions between intragraft Ad-IL-13 gene transfer and systemic infusion of regulatory cells. Although exogenous viral IL-13 was modestly effective on its own, adjunctive Ad-IL-13 gene therapy and adoptive transfer of suboptimal dose of regulatory T cells exerted synergistic effects, as evidenced by long-term cardiac allograft survival in test recipients. Local IL-13 induction (determined by enzyme-linked immunosorbent assay and immunohistology) diminished intragraft apoptosis, and upregulated antiapoptotic A20 and antioxidant heme oxygenase 1 (HO-1). Ad-IL-13 plus regulatory cells synergistically diminished the frequency of cells positive by TUNEL (TdT [terminal deoxynucleotidyltransferase]-mediated dUTP nick-end labeling) assay, and enhanced cytoprotective gene expression. These findings correlated with in vitro studies in which Ad-IL-13 decreased tumor necrosis factor alpha (TNF-alpha)-mediated cytotoxicity, conferred resistance to apoptosis, and increased HO-1/A20 expression in human umbilical vein endothelial cell (HUVEC) cultures. However, inhibition of HO-1 after treatment with tin protoporphyrin reversed the immunomodulatory/antiapoptotic effects of Ad-IL-13 both in vivo (infectious transplantation tolerance), and in vitro (HUVECs). Thus, by decreasing apoptosis/TNF-alpha-mediated cytotoxicity, and by facilitating induction of antiapoptotic/antioxidant molecules in HUVECs, this study documents the cytoprotective function of Ad-IL-13 in vitro, and points toward in vivo synergy between Ad-IL-13 and regulatory cells in the infectious transplantation tolerance pathway. Results of HO-1 neutralization studies suggest that HO-1 represents one of the putative IL-13 downstream effectors.
authors.affiliation: Dumont-UCLA Transplant Center, Department of Surgery, UCLA School of Medicine, Los Angeles, CA 90095, USA.
authors.forename: Bibo
authors.initials: B
authors.lastname: Ke
authors.forename: Xiu-Da
authors.initials: XD
authors.lastname: Shen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhai
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Busuttil
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Volk
authors.forename: Jerzy W
authors.initials: JW
authors.lastname: Kupiec-Weglinski
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000627:therapeutic use; D017209:Apoptosis / Q000502:physiology*; D015704:CD4 Antigens / Q000276:immunology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D015316:Genetic Therapy; D006084:Graft Rejection / Q000517:prevention & control; D016027:Heart Transplantation / Q000276:immunology*; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors / Q000502:physiology*; D051547:Heme Oxygenase-1; D006801:Humans; D007108:Immune Tolerance / Q000502:physiology; D016219:Immunotherapy, Adoptive; D018793:Interleukin-13 / Q000235:genetics / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins; D008665:Metalloporphyrins / Q000494:pharmacology; D011524:Protoporphyrins / Q000494:pharmacology; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D016038:Skin Transplantation; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014184:Transplantation, Homologous / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D014471:Umbilical Veins
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D004791:Enzyme Inhibitors; D018793:Interleukin-13; D008565:Membrane Proteins; D008665:Metalloporphyrins; D011524:Protoporphyrins; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; C032628:tin protoporphyrin IX; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1