Shigatoxin triggers thrombotic thrombocytopenic purpura in genetically susceptible ADAMTS13-deficient mice
David G. Motto, Anil K. Chauhan, Guojing Zhu, Jonathon Homeister, Colin B. Lamb, Karl C. Desch, Weirui Zhang, Han-Mou Tsai, Denisa D. Wagner, David Ginsburg
David G. Motto, Anil K. Chauhan, Guojing Zhu, Jonathon Homeister, Colin B. Lamb, Karl C. Desch, Weirui Zhang, Han-Mou Tsai, Denisa D. Wagner, David Ginsburg
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Research Article Hematology

Shigatoxin triggers thrombotic thrombocytopenic purpura in genetically susceptible ADAMTS13-deficient mice

Abstract

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening illness caused by deficiency of the vWF-cleaving protease ADAMTS13. Here we show that ADAMTS13-deficient mice are viable and exhibit normal survival, although vWF-mediated platelet-endothelial interactions are significantly prolonged. Introduction of the genetic background CASA/Rk (a mouse strain with elevated plasma vWF) resulted in the appearance of spontaneous thrombocytopenia in a subset of ADAMTS13-deficient mice and significantly decreased survival. Challenge of these mice with shigatoxin (derived from bacterial pathogens associated with the related human disease hemolytic uremic syndrome) resulted in a striking syndrome closely resembling human TTP. Surprisingly, no correlation was observed between plasma vWF level and severity of TTP, implying the existence of TTP-modifying genes distinct from vWF. These data suggest that microbe-derived toxins (or possibly other sources of endothelial injury), together with additional genetic susceptibility factors, are required to trigger TTP in the setting of ADAMTS13 deficiency.

Authors

David G. Motto, Anil K. Chauhan, Guojing Zhu, Jonathon Homeister, Colin B. Lamb, Karl C. Desch, Weirui Zhang, Han-Mou Tsai, Denisa D. Wagner, David Ginsburg

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Figure 1

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Generation of ADAMTS13-deficient mice. (A) Schematic diagrams of the wil...
Generation of ADAMTS13-deficient mice. (A) Schematic diagrams of the wild-type and targeted Adamts13 alleles and the targeting vector. Exons are indicated as numbered boxes. The locations of PCR primers used in B are indicated by lower-case letters and arrows. The locations of selected restriction sites are indicated by upper-case letters (E, EcoRI; H, HindIII; and S, SpeI). (B) Genomic PCR demonstrating correct targeting of the Adamts13 gene. Lanes 1, 4, and 7: primers a + b; lanes 2, 5, and 8: primers c + d + e; and lanes 3, 6, and 9: primers f + g. A 240-bp band specific for the Neo insertion is seen only in Adamts13+/– and Adamts13–/– mice (lanes 4 and 7); a 280-bp band specific for the targeting vector is seen only in Adamts13+/– and Adamts13–/– mice (lanes 5 and 8); a 370-bp specific for the wild-type allele is seen only in Adamts13+/+ and Adamts13+/– mice (lanes 2 and 5); and a 400-bp band specific for deleted exon 6 is seen only in Adamts13+/+ and Adamts13+/– mice (lanes 3 and 6) and is not seen in Adamts13–/– mice (lane 9). (C) RT-PCR of liver mRNA prepared from Adamts13B/129+/+, Adamts13B/129+/–, and Adamts13B/129–/– mice. Primers specific for exons 1–6 of Adamts13 (upper panel) or vWF (lower panel) were used. Adamts13 exons 1–6 were readily detected in mRNA from Adamts13B/129+/+ and Adamts13B/129+/– mice but were absent in mRNA from Adamts13B/129–/– mice.