title: Transgenic expression of the human A20 gene in cloned pigs provides protection against apoptotic and inflammatory stimuli.
abstract: BACKGROUND
  Porcine organs with transgenic expression of anti-apoptotic and anti-inflammatory genes like the human A20 gene (hA20), a tumor necrosis factor-alpha (TNF-alpha)-inducible gene, may control the acute vascular rejection (AVR) of porcine xenografts. The human A20 molecule possesses protective features against inflammatory and apoptotic stimuli in various cell types including endothelial cells, rendering it a promising candidate for transgenic pig production in the context of xenotransplantation. Here, we produced pigs transgenic for hA20 and investigated whether hA20-transgenic porcine aortic endothelial cells (PAECs) were resistant against the induction of apoptosis in vitro and to what extent hA20-transgenic porcine hearts were protected against ischemia/reperfusion (I/R) injury.
  
  
  METHODS
  Porcine fetal fibroblasts (PFFs) were transfected with the vector pCAGGSEhA20-IRESNEO containing a chicken beta-actin/rabbit beta-globin (CAGGS)-promoter element, known to provide ubiquitous gene expression in both mice and pigs. Transfected PFFs were then used in somatic cell nuclear transfer (SCNT). Three hA20-transgenic pigs were killed for PAEC isolation and organ mRNA and protein expression analysis by reverse transcriptase-polymerase chain reaction (RT-PCR), Northern and Western Blotting. PAECs were tested for susceptibility to apoptosis after TNF-alpha challenging and triggering of the CD95(Fas)/CD95Ligand pathway. Five transgenic and three wild type animals were subjected to an I/R experiment followed by measurement of infarct size, myeloperoxidase (MPO) activity and subendocardial segmental shortening (SES) to assess protective effects of hA20 in the porcine myocardium.
  
  
  RESULTS
  The hA20-transgenic pigs developed normally and expression of hA20 was found in skeletal muscle, heart and PAECs. Cultured human A20-transgenic PAECs showed significantly reduced apoptosis when compared to their wild type counterparts and were less susceptible to the induction of cell death by CD95(Fas)L. Only partial protection of hA20-transgenic pig hearts was observed after I/R. While infarct size did not differ between the two groups after ischemic assault, hA20-transgenic porcine hearts showed significantly lower MPO activity and better hemodynamic performance (determined as SES) than their wild type counterparts.
  
  
  CONCLUSIONS
  The hA20 gene was for the first time functionally expressed in transgenic pigs. Although the CAGGS is a ubiquitous promoter element, expression was restricted to heart, skeletal muscle and PAECs of transgenic animals. Cultivated hA20-transgenic PAECs were protected against TNF-alpha-mediated apoptosis, and partially protected against CD95(Fas)L-mediated cell death; cardiomyocytes were partially protected in I/R. These findings reveal hA20 as a promising molecule for controlling AVR in multi-transgenic pigs for xenotransplantation studies.
authors.affiliation: Institute of Farm Animal Genetics, Mariensee, Neustadt, Germany.
authors.forename: Marianne
authors.initials: M
authors.lastname: Oropeza
authors.forename: Björn
authors.initials: B
authors.lastname: Petersen
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Carnwath
authors.forename: Andrea
authors.initials: A
authors.lastname: Lucas-Hahn
authors.forename: Erika
authors.initials: E
authors.lastname: Lemme
authors.forename: Petra
authors.initials: P
authors.lastname: Hassel
authors.forename: Doris
authors.initials: D
authors.lastname: Herrmann
authors.forename: Brigitte
authors.initials: B
authors.lastname: Barg-Kues
authors.forename: Stephanie
authors.initials: S
authors.lastname: Holler
authors.forename: Anna-Lisa
authors.initials: AL
authors.lastname: Queisser
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schwinzer
authors.forename: Rabea
authors.initials: R
authors.lastname: Hinkel
authors.forename: Christian
authors.initials: C
authors.lastname: Kupatt
authors.forename: Heiner
authors.initials: H
authors.lastname: Niemann
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis / Q000276:immunology*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D053222:Fas Ligand Protein / Q000276:immunology; D005260:Female; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000276:immunology*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009203:Myocardial Infarction / Q000276:immunology / Q000473:pathology; D017202:Myocardial Ischemia; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D053652:Nuclear Transfer Techniques; D011247:Pregnancy; D013552:Swine; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D004268:DNA-Binding Proteins; D053222:Fas Ligand Protein; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D014409:Tumor Necrosis Factor-alpha; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3