title: Transgenic overexpression of a stable Plasminogen Activator Inhibitor-1 variant.
abstract: BACKGROUND
  Plasminogen Activator Inhibitor-1 (PAI-1) is a member of the Serine Protease Inhibitor (SERPIN) gene family and a key regulator of fibrinolysis. PAI-1 is unique among SERPINs in its spontaneous transition to a latent, inactive state, with a half-life of approximately 2 hours under physiologic conditions. The biologic importance of the PAI-1 transition to latency is unknown. This study aimed to engineer transgenic overexpression of a stable murine PAI-1 variant to examine the physiologic effects in vivo from delayed transition of PAI-1 to latency.
  
  
  METHODS
  Ten independent transgenic lines were generated with expression of a stable PAI-1 variant driven by the hybrid CMV/chicken beta-actin promoter.
  
  
  RESULTS
  Plasma PAI-1 levels in the transgenic founders ranged from 3.1+/-0.1 ng/mL to 1268.8+/-717.0 ng/mL. Quantitative PCR analysis in 3 transgenic lines demonstrated elevated PAI-1 mRNA in multiple tissues, with the highest increases observed in liver, brain, heart, and kidney. The fold-increase in PAI-1 mRNA over wild-type ranged from 2-fold to >2000-fold. Immunohistochemistry showed increased PAI-1 in liver, kidney, heart, spleen, and lung. Histologic examination of transgenic mice showed no evidence of thrombosis. The two founders with the highest plasma PAI-1 levels failed to produce any transgenic offspring that survived to weaning, although genotyping of expired pups revealed successful transmission of the transgene.
  
  
  CONCLUSIONS
  These results suggest that high expression of a stable variant of PAI-1 may be lethal in mice, while more moderate expression is generally well tolerated and produces no apparent thrombosis.
authors.affiliation: Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Abigail T
authors.initials: AT
authors.lastname: Fahim
authors.forename: He
authors.initials: H
authors.lastname: Wang
authors.forename: Jining
authors.initials: J
authors.lastname: Feng
authors.forename: David
authors.initials: D
authors.lastname: Ginsburg
mesh_terms: D000818:Animals; D008168:Lung / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D019076:Transgenes
chemical_list: D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger
references.citation: Blood. 1996 Jun 1;87(11):4718-22
references.pmid: 8639841
references.citation: J Thromb Haemost. 2005 Jan;3(1):35-45
references.pmid: 15634264
references.citation: Dev Biol. 1986 Nov;118(1):9-18
references.pmid: 3770310
references.citation: Nature. 1992 Jan 16;355(6357):270-3
references.pmid: 1731226
references.citation: J Biol Chem. 1994 Jun 10;269(23):15957-60
references.pmid: 8206889
references.citation: N Engl J Med. 1992 Dec 10;327(24):1729-33
references.pmid: 1435917
references.citation: Curr Opin Pharmacol. 2005 Apr;5(2):149-54
references.pmid: 15780823
references.citation: Blood. 2000 Jan 15;95(2):577-80
references.pmid: 10627465
references.citation: Nature. 1991 Oct 10;353(6344):576-8
references.pmid: 1922367
references.citation: J Biol Chem. 1992 Apr 15;267(11):7588-95
references.pmid: 1559996
references.citation: Transgenic Res. 1993 Jan;2(1):29-32
references.pmid: 8513336
references.citation: J Clin Invest. 1996 Jan 1;97(1):232-7
references.pmid: 8550840
references.citation: J Biol Chem. 1994 Nov 4;269(44):27657-62
references.pmid: 7961684
references.citation: Mol Reprod Dev. 1999 Sep;54(1):43-8
references.pmid: 10423296
references.citation: Thromb Haemost. 1995 Nov;74(5):1305-9
references.pmid: 8607114
references.citation: Gene. 1991 Dec 15;108(2):193-9
references.pmid: 1660837
references.citation: Nature. 1994 Mar 31;368(6470):419-24
references.pmid: 8133887
references.citation: Bone. 2007 Dec;41(6):995-1004
references.pmid: 17888748
references.citation: Nature. 1990 Jul 5;346(6279):74-6
references.pmid: 2366866
references.citation: Blood. 1997 Jul 1;90(1):204-8
references.pmid: 9207454
references.citation: Exp Cell Res. 1998 Oct 10;244(1):367-9
references.pmid: 9770380
references.citation: Circulation. 2002 Jul 23;106(4):491-6
references.pmid: 12135951
references.citation: Diabet Med. 1993 Aug-Sep;10(7):638-42
references.pmid: 8403825
references.citation: Eur J Biochem. 1989 Dec 22;186(3):523-33
references.pmid: 2514093
references.citation: Blood. 1991 Feb 1;77(3):528-32
references.pmid: 1899347
references.citation: Biochem Biophys Res Commun. 2004 Mar 5;315(2):363-8
references.pmid: 14766216
references.citation: J Biol Chem. 1988 Oct 25;263(30):15454-61
references.pmid: 2459123
references.citation: J Clin Invest. 1993 Dec;92(6):2756-60
references.pmid: 8254029
references.citation: FEBS Lett. 1997 May 5;407(3):313-9
references.pmid: 9175875
references.citation: J Mol Biol. 2001 Jan 26;305(4):773-83
references.pmid: 11162091
references.citation: Arterioscler Thromb Vasc Biol. 2003 Jan 1;23(1):78-84
references.pmid: 12524228
references.citation: Genesis. 2000 Nov-Dec;28(3-4):167-74
references.pmid: 11105060
references.citation: J Mol Endocrinol. 2007 Jul;39(1):9-16
references.pmid: 17601881
references.citation: Nucleic Acids Res. 1997 Jul 15;25(14):2745-51
references.pmid: 9207020
references.citation: Lancet. 1987 Jul 4;2(8549):3-9
references.pmid: 2885513
references.citation: N Engl J Med. 1985 Dec 19;313(25):1557-63
references.pmid: 3934538
references.citation: EMBO J. 1995 Jul 3;14(13):2969-77
references.pmid: 7621813