Svoboda | Graniru | BBC Russia | Golosameriki | Facebook

TREM-like transcript-1 protects against inflammation-associated hemorrhage by facilitating platelet aggregation in mice and humans

J Clin Invest. 2009 Jun;119(6):1489-501. doi: 10.1172/JCI36175. Epub 2009 May 11.

Abstract

Triggering receptor expressed on myeloid cells-like (TREM-like) transcript-1 (TLT-1), a type 1 single Ig domain orphan receptor specific to platelet and megakaryocyte alpha-granules, relocates to the platelet surface upon platelet stimulation. We found here that patients diagnosed with sepsis, in contrast to healthy individuals, had substantial levels of soluble TLT-1 (sTLT-1) in their plasma that correlated with the presence of disseminated intravascular coagulation. sTLT-1 bound to fibrinogen and augmented platelet aggregation in vitro. Furthermore, the cytoplasmic domain of TLT-1 could also bind ezrin/radixin/moesin family proteins, suggesting its ability to link fibrinogen to the platelet cytoskeleton. Accordingly, platelets of Treml1-/- mice failed to aggregate efficiently, extending tail-bleeding times. Lipopolysaccharide-treated Treml1-/- mice developed higher plasma levels of TNF and D-dimers than wild-type mice and were more likely to succumb during challenge. Finally, Treml1-/- mice were predisposed to hemorrhage associated with localized inflammatory lesions. Taken together, our findings suggest that TLT-1 plays a protective role during inflammation by dampening the inflammatory response and facilitating platelet aggregation at sites of vascular injury. Therefore, therapeutic modulation of TLT-1-mediated effects may provide clinical benefit to patients with hypercoagulatory conditions, including those associated with inflammation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Fibrinogen / metabolism
  • Hemorrhage / complications
  • Hemorrhage / genetics
  • Hemorrhage / metabolism*
  • Humans
  • Inflammation / complications
  • Inflammation / genetics
  • Inflammation / metabolism
  • Lipopolysaccharides / pharmacology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Platelet Aggregation* / drug effects
  • Protein Binding
  • Receptors, Immunologic / blood*
  • Receptors, Immunologic / deficiency
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Recombinant Proteins / pharmacology
  • Sepsis / blood
  • Solubility

Substances

  • Lipopolysaccharides
  • Receptors, Immunologic
  • Recombinant Proteins
  • TREML1 protein, human
  • Treml1 protein, mouse
  • Fibrinogen