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Megakaryocytic cells synthesize and platelets secrete alpha5-laminins, and the endothelial laminin isoform laminin 10 (alpha5beta1gamma1) strongly promotes adhesion but not activation of platelets

Nigatu, Ayele ; Sime, Wondossen LU ; Gorfu, Gezahegn ; Geberhiwot, Tarekegn ; Andurén, Ingegerd ; Ingerpuu, Sulev ; Doi, Masayuki ; Tryggvason, Karl ; Hjemdahl, Paul and Patarroyo, Manuel (2006) In Thrombosis and Haemostasis 95(1). p.85-93
Abstract

Following vascular injury, basement membrane (BM) components of the blood vessels are exposed to circulating cells and may contribute to hemostasis and/or thrombosis. Laminins 8 (LN-8) (alpha4beta1gamma1) and 10 (LN-10) (alpha5beta1gamma1) are major laminin isoforms of the endothelial BM, and LN-8 is also secreted by activated platelets. In the present study, we demonstrate synthesis of alpha5-laminins LN-10 and LN-11 (alpha5beta2gamma1) by megakaryocytic cells, and intracellular expression of these laminin isoforms in blood platelets. In contrast to platelet LN alpha4 chain that had an apparent molecular weight of 180 kDa and associated mostly to LNbeta1 chain, platelet LNalpha5 consisted of 300/350 kDa polypeptides and associated... (More)

Following vascular injury, basement membrane (BM) components of the blood vessels are exposed to circulating cells and may contribute to hemostasis and/or thrombosis. Laminins 8 (LN-8) (alpha4beta1gamma1) and 10 (LN-10) (alpha5beta1gamma1) are major laminin isoforms of the endothelial BM, and LN-8 is also secreted by activated platelets. In the present study, we demonstrate synthesis of alpha5-laminins LN-10 and LN-11 (alpha5beta2gamma1) by megakaryocytic cells, and intracellular expression of these laminin isoforms in blood platelets. In contrast to platelet LN alpha4 chain that had an apparent molecular weight of 180 kDa and associated mostly to LNbeta1 chain, platelet LNalpha5 consisted of 300/350 kDa polypeptides and associated mainly to LNbeta2. Both alpha4- and alpha5-laminins were secreted by platelets following stimulation. When compared to recombinant human (rh) LN-8, rhLN-10 was much more adhesive to platelets, though adhesion to both proteins was largely mediated via alpha6beta1 integrin. In spite of their adhesive properties, rhLN-8 and rhLN-10 induced neither P-selectin expression nor cell aggregation, two signs of platelet activation. This study demonstrates synthesis/expression of heterotrimeric alpha5-laminins in hematopoietic/blood cells, and provides evidence for the adhesive, but not activating, role of endothelial laminin isoforms in platelet biology.

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author
; ; ; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
keywords
Blood Platelets/drug effects, Cell Adhesion, Cell Line, Tumor, Humans, Laminin/chemistry, Megakaryocytes/metabolism, Molecular Weight, Protein Structure, Quaternary, Recombinant Proteins/metabolism
in
Thrombosis and Haemostasis
volume
95
issue
1
pages
9 pages
publisher
Schattauer GmbH
external identifiers
  • scopus:33645534906
  • pmid:16543966
ISSN
0340-6245
DOI
10.1160/TH05-04-0281
language
English
LU publication?
no
id
9711563a-c4d1-4c84-8f83-bcfa4e30bffd
date added to LUP
2024-09-30 20:19:57
date last changed
2024-10-01 08:05:09
@article{9711563a-c4d1-4c84-8f83-bcfa4e30bffd,
  abstract     = {{<p>Following vascular injury, basement membrane (BM) components of the blood vessels are exposed to circulating cells and may contribute to hemostasis and/or thrombosis. Laminins 8 (LN-8) (alpha4beta1gamma1) and 10 (LN-10) (alpha5beta1gamma1) are major laminin isoforms of the endothelial BM, and LN-8 is also secreted by activated platelets. In the present study, we demonstrate synthesis of alpha5-laminins LN-10 and LN-11 (alpha5beta2gamma1) by megakaryocytic cells, and intracellular expression of these laminin isoforms in blood platelets. In contrast to platelet LN alpha4 chain that had an apparent molecular weight of 180 kDa and associated mostly to LNbeta1 chain, platelet LNalpha5 consisted of 300/350 kDa polypeptides and associated mainly to LNbeta2. Both alpha4- and alpha5-laminins were secreted by platelets following stimulation. When compared to recombinant human (rh) LN-8, rhLN-10 was much more adhesive to platelets, though adhesion to both proteins was largely mediated via alpha6beta1 integrin. In spite of their adhesive properties, rhLN-8 and rhLN-10 induced neither P-selectin expression nor cell aggregation, two signs of platelet activation. This study demonstrates synthesis/expression of heterotrimeric alpha5-laminins in hematopoietic/blood cells, and provides evidence for the adhesive, but not activating, role of endothelial laminin isoforms in platelet biology.</p>}},
  author       = {{Nigatu, Ayele and Sime, Wondossen and Gorfu, Gezahegn and Geberhiwot, Tarekegn and Andurén, Ingegerd and Ingerpuu, Sulev and Doi, Masayuki and Tryggvason, Karl and Hjemdahl, Paul and Patarroyo, Manuel}},
  issn         = {{0340-6245}},
  keywords     = {{Blood Platelets/drug effects; Cell Adhesion; Cell Line, Tumor; Humans; Laminin/chemistry; Megakaryocytes/metabolism; Molecular Weight; Protein Structure, Quaternary; Recombinant Proteins/metabolism}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{85--93}},
  publisher    = {{Schattauer GmbH}},
  series       = {{Thrombosis and Haemostasis}},
  title        = {{Megakaryocytic cells synthesize and platelets secrete alpha5-laminins, and the endothelial laminin isoform laminin 10 (alpha5beta1gamma1) strongly promotes adhesion but not activation of platelets}},
  url          = {{http://dx.doi.org/10.1160/TH05-04-0281}},
  doi          = {{10.1160/TH05-04-0281}},
  volume       = {{95}},
  year         = {{2006}},
}