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Platelet-derived growth factor receptors expressed in response to injury of differentiated vascular smooth muscle in vitro: effects on Ca2+ and growth signals

Lindqvist, A; Nilsson, Bengt-Olof LU ; Ekblad, Eva LU and Hellstrand, Per LU (2001) In Acta Physiologica Scandinavica1888-12-31+01:002006-01-01+01:00 173(2). p.175-175
Abstract
Vascular smooth muscle cells (VSMCs) in the intact vascular wall are differentiated for contraction, whereas the response to vascular injury involves transition towards a synthetic phenotype, with increased tendency for proliferation. Platelet-derived growth factor (PDGF) is thought to be important for this process. We investigated expression and functional coupling of PDGF receptors (PDGFRs) alpha and beta in rat tail arterial rings kept in organ culture, in order to capture early events in the phenotypic transition. In freshly dissected rings no PDGFR immunoreactivity was found in medial VSMCs, whereas PDGFR alpha was detected in nerve fibres. After organ culture for 1-4 days PDGFR alpha and beta as well as phospholipase Cgamma2... (More)
Vascular smooth muscle cells (VSMCs) in the intact vascular wall are differentiated for contraction, whereas the response to vascular injury involves transition towards a synthetic phenotype, with increased tendency for proliferation. Platelet-derived growth factor (PDGF) is thought to be important for this process. We investigated expression and functional coupling of PDGF receptors (PDGFRs) alpha and beta in rat tail arterial rings kept in organ culture, in order to capture early events in the phenotypic transition. In freshly dissected rings no PDGFR immunoreactivity was found in medial VSMCs, whereas PDGFR alpha was detected in nerve fibres. After organ culture for 1-4 days PDGFR alpha and beta as well as phospholipase Cgamma2 (PLCgamma2), known to couple to PDGFR, were expressed in VSMCs within 100 microm of the cut ends. Calponin, a marker for the contractile phenotype, was decreased near the injured area, suggesting that cells were in transition towards synthetic phenotype. In these cells, which showed functional Ca2+-release from the sarcoplasmic reticulum, PDGF-AB (100 ng x mL(-1)) had no effect on [Ca2+]i, whereas cultured VSMCs obtained from explants of rat tail arterial rings responded to PDGF-AB with an increase in [Ca2+]i. However, PDGFR within the cultured rings coupled to growth signalling pathways, as PDGF-AB caused a tyrphostin AG1295-sensitive activation of extracellular signal-regulated kinases 1 and 2 and of [3H]-thymidine incorporation. Thus, early expression of PDGFR in VSMC adjacent to sites of vascular injury coincides with signs of dedifferentiation. These receptors couple to growth signalling, but do not activate intracellular Ca2+ release. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
Acta Physiologica Scandinavica1888-12-31+01:002006-01-01+01:00
volume
173
issue
2
pages
175 - 175
publisher
Wiley-Blackwell
external identifiers
  • pmid:11683675
  • scopus:0034781921
ISSN
0001-6772
language
English
LU publication?
yes
id
d5178946-78c2-401f-9cc0-28a2ade50cb0 (old id 1122011)
date added to LUP
2008-07-03 13:40:07
date last changed
2018-05-29 09:38:54
@article{d5178946-78c2-401f-9cc0-28a2ade50cb0,
  abstract     = {Vascular smooth muscle cells (VSMCs) in the intact vascular wall are differentiated for contraction, whereas the response to vascular injury involves transition towards a synthetic phenotype, with increased tendency for proliferation. Platelet-derived growth factor (PDGF) is thought to be important for this process. We investigated expression and functional coupling of PDGF receptors (PDGFRs) alpha and beta in rat tail arterial rings kept in organ culture, in order to capture early events in the phenotypic transition. In freshly dissected rings no PDGFR immunoreactivity was found in medial VSMCs, whereas PDGFR alpha was detected in nerve fibres. After organ culture for 1-4 days PDGFR alpha and beta as well as phospholipase Cgamma2 (PLCgamma2), known to couple to PDGFR, were expressed in VSMCs within 100 microm of the cut ends. Calponin, a marker for the contractile phenotype, was decreased near the injured area, suggesting that cells were in transition towards synthetic phenotype. In these cells, which showed functional Ca2+-release from the sarcoplasmic reticulum, PDGF-AB (100 ng x mL(-1)) had no effect on [Ca2+]i, whereas cultured VSMCs obtained from explants of rat tail arterial rings responded to PDGF-AB with an increase in [Ca2+]i. However, PDGFR within the cultured rings coupled to growth signalling pathways, as PDGF-AB caused a tyrphostin AG1295-sensitive activation of extracellular signal-regulated kinases 1 and 2 and of [3H]-thymidine incorporation. Thus, early expression of PDGFR in VSMC adjacent to sites of vascular injury coincides with signs of dedifferentiation. These receptors couple to growth signalling, but do not activate intracellular Ca2+ release.},
  author       = {Lindqvist, A and Nilsson, Bengt-Olof and Ekblad, Eva and Hellstrand, Per},
  issn         = {0001-6772},
  language     = {eng},
  number       = {2},
  pages        = {175--175},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Physiologica Scandinavica1888-12-31+01:002006-01-01+01:00},
  title        = {Platelet-derived growth factor receptors expressed in response to injury of differentiated vascular smooth muscle in vitro: effects on Ca2+ and growth signals},
  volume       = {173},
  year         = {2001},
}