title: The development of cardiac fibrosis in low tissue factor mice is gender-dependent and is associated with differential regulation of urokinase plasminogen activator.
abstract: Tissue factor (TF) initiates the protease coagulation cascade in response to tissue injury. Homozygous deficiency of murine TF results in embryonic lethality, which is rescued by low-level expression of human TF. These low-TF mice have been shown to develop cardiac fibrosis. We tested the hypothesis that the development of cardiac fibrosis in low-TF mice results from dysregulated protease expression and is affected by gender. Mice were divided into the age groups 2-5, 6-12, 13-18 and 19+ weeks. Fibrosis was assessed by trichrome staining. Protease expression was measured in male and female mice by RT-PCR for mRNA and zymography, ELISA or immunoblot for protein. Urokinase plasminogen activator (uPA) activity was determined by zymography and chromogenic substrate assay. A marked gender effect was noted for the development of fibrosis, with interstitial collagen deposition occurring from 9 weeks in male low-TF mice, but not until 19 weeks in low-TF females. This delayed onset in females was accompanied by delayed up-regulation of molecular markers of injury. Matrix metalloproteinase (MMP)-3 and tissue inhibitor of metalloproteinase (TIMP)-1 expression were up-regulated in the hearts of male low-TF mice from 6 to 12 weeks and in females from 19 weeks. MMP/TIMP dysregulation was not seen prior to cardiac fibrosis and did not appear to explain the gender differences. However, uPA expression and activity were down-regulated prior to cardiac fibrosis in low-TF females, but were up-regulated in age-matched males. This suggests that the down-regulation of uPA in female low-TF mice protects them from more severe cardiac fibrosis.
authors.affiliation: Renal Research Laboratory, University of New South Wales, Level 2, Clinical Sciences Building, Prince of Wales Hospital, Randwick, NSW 2031, Australia. dr.darrendavis@gmail.com <dr.darrendavis@gmail.com>
authors.forename: Darren R
authors.initials: DR
authors.lastname: Davis
authors.forename: Kate
authors.initials: K
authors.lastname: Wilson
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Sam
authors.forename: Sean E
authors.initials: SE
authors.lastname: Kennedy
authors.forename: Nigel
authors.initials: N
authors.lastname: Mackman
authors.forename: John A
authors.initials: JA
authors.lastname: Charlesworth
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Erlich
mesh_terms: D000818:Animals; D015415:Biomarkers; D055513:Connective Tissue Growth Factor; D015536:Down-Regulation; D004719:Endomyocardial Fibrosis / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D008297:Male; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018384:Oxidative Stress; D012333:RNA, Messenger / Q000235:genetics; D012727:Sex Characteristics; D013925:Thromboplastin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000378:metabolism*
chemical_list: D015415:Biomarkers; C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D019714:Tissue Inhibitor of Metalloproteinases; D055513:Connective Tissue Growth Factor; D013925:Thromboplastin; D014568:Urokinase-Type Plasminogen Activator; D020782:Matrix Metalloproteinases