Thromb Haemost 2005; 94(05): 1019-1027
DOI: 10.1160/TH05-02-0115
Platelets and Blood Cells
Schattauer GmbH

Shiga toxin 2 and lipopolysaccharide cause monocytic THP-1 cells to release factors which activate platelet function

Fadila Guessous
1   Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
,
Marek Marcinkiewicz
1   Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
,
Renata Polanowska-Grabowska
1   Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
,
Tiffany R. Keepers
2   Division of Nephrology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
,
Tom Obrig
2   Division of Nephrology, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
,
Adrian R. L. Gear
1   Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
› Author Affiliations

Financial support: This study was supported by Public Health Service Grants DK59004 (to A.R.L. Gear) and AI 24431 (to T. Obrig).
Further Information

Publication History

Received: 16 February 2005

Accepted after resubmission: 08 August 2005

Publication Date:
14 December 2017 (online)

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Summary

Platelet and monocyte activation may contribute to hemolytic anemia, thrombocytopenia and renal failure associated with the hemolytic uremic syndrome (HUS) caused by Escherichia coli O157:H7. Since Shiga toxins (Stxs) and lipopolysaccharide (LPS) from this bacterium are implicated in the pathogenesis of HUS, we examined whether stimulation of THP-1 human monocytic cells by Shiga toxin 2 (Stx2) and LPS can lead to the activation of platelet function. We now show that Stx2 caused THP-1 cells to release the chemokines IL-8, MDC, and RANTES and that the presence of LPS further stimulated this release. IL-8 was produced in greatest amount and was an effective co-agonist for inducing platelet aggregation. Primary human monocytes also released large amounts of IL-8 in response to LPS and Stx2. Factors released by THP-1 cells exposed to Stx2 and LPS activated platelet function as evidenced by increased aggregation, serotonin secretion, P-selectin exposure and by the formation of stable platelet-monocyte aggregates. Our data therefore show that monocytes exposed to E. coli-derived Stx2 and LPS release factors which activate platelet function.