Thrombin-activatable fibrinolysis inhibitor (TAFI) deficiency is compatible with murine life
Mariko Nagashima, … , William P. Fay, John Morser
Mariko Nagashima, … , William P. Fay, John Morser
Published January 1, 2002
Citation Information: J Clin Invest. 2002;109(1):101-110. https://doi.org/10.1172/JCI12119.
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Article

Thrombin-activatable fibrinolysis inhibitor (TAFI) deficiency is compatible with murine life

Abstract

To investigate the consequence of deficiency in thrombin-activatable fibrinolysis inhibitor (TAFI), we generated homozygous TAFI-deficient mice by targeted gene disruption. Intercrossing of heterozygous TAFI mice produced offspring in the expected Mendelian ratio, indicating that transmission of the mutant TAFI allele did not lead to embryonic lethality. TAFI-deficient mice developed normally, reached adulthood, and were fertile. No gross physical abnormalities were observed up to 24 months of age. Hematological analysis of TAFI-deficient mice did not show any major differences including plasma fibrinogen level, prothrombin time, and activated partial thromboplastin time. TAFI-deficient mice did not suffer from excess bleeding as determined by blood loss following tail transection, although their plasma failed to prolong clot lysis time in vitro. In vivo, TAFI deficiency did not influence occlusion time in either an arterial or a venous injury model. TAFI deficiency did not improve survival rate compared with the wild-type in thrombin-induced thromboembolism, factor X coagulant protein–induced thrombosis, and endotoxin-induced disseminated intravascular coagulation. Furthermore, TAFI deficiency did not alter kaolin-induced writhing response, implying that TAFI does not play a major role in bradykinin catabolism. The current study demonstrates that TAFI deficiency does not change normal responses to acute challenges.

Authors

Mariko Nagashima, Zheng-Feng Yin, Lei Zhao, Kathy White, Yanhong Zhu, Nina Lasky, Meredith Halks-Miller, George J. Broze Jr., William P. Fay, John Morser

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Figure 1

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TAFI gene-disruption in mice. (a) TAFI replacement construct and partial...
TAFI gene-disruption in mice. (a) TAFI replacement construct and partial restriction map of the endogenous locus. Exon 8 and 9 encodes some of the zinc and substrate binding sites of TAFI. (b) Southern blot analysis of TAFI gene disruption. The probe indicated in a was used to detect 9.2-kb DNA fragment in the wild-type allele and 7.0-kb DNA fragment in the mutant allele following Sac1 digestion of genomic DNA. (c) Western blot analysis of plasma TAFI from the wild-type, heterozygous, and homozygous TAFI mice. Ab raised against TAFI peptide (CGIHAREWISPAF) hybridized to a band with a molecular weight similar to that of murine albumin only in the plasma from the wild-type and heterozygous mice. (d) RT-PCR analysis of liver mRNA isolated from TAFI+/+, TAFI+/–, and TAFI–/– mice. RT-PCR products obtained with primers that span the entire coding region of TAFI cDNA in the presence of reverse transcriptase (RT) are shown on the left-hand side and those in the absence of reverse transcriptase are on the right-hand side. Neo, neomycin phosphotransferase gene; tk, thymidine kinase gene; probe, TAFI-specific probe used in Southern blot analysis (which encodes exon 6).