The development of cardiac fibrosis in low tissue factor mice is gender-dependent and is associated with differential regulation of urokinase plasminogen activator.
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.
Davis
Darren R
DR
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>
Wilson
Kate
K
Sam
Melissa J
MJ
Kennedy
Sean E
SE
Mackman
Nigel
N
Charlesworth
John A
JA
Erlich
Jonathan H
JH
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*
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