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Angiotensin II type 1 receptors stimulate protein synthesis in human cardiac fibroblasts via a Ca2+-sensitive PKC-dependent tyrosine kinase pathway

Hou, M; Pantev, E; Moller, S; Erlinge, David LU and Edvinsson, Lars LU (2000) In Acta Physiologica Scandinavica 168(2). p.301-309
Abstract
The aim of the present study was to investigate the proliferative effects of Ang II in human cardiac fibroblasts. The effects of Ang II in human cardiac fibroblasts on the 3H-thymidine incorporation, the cell number, the 3H-leucine incorporation and the total protein content were measured. The expression of receptor mRNA was performed by reverse transcription-polymerase chain reaction (RT-PCR). Ang II increased 3H-leucine incorporation in a concentration-dependent manner but not 3H-thymidine incorporation in primary cultures of human cardiac fibroblasts. The maximum effect (24 +/- 3% over control) was obtained at a concentration of 10 nM. There were no significant alterations of cell number or total protein content, suggesting that Ang II... (More)
The aim of the present study was to investigate the proliferative effects of Ang II in human cardiac fibroblasts. The effects of Ang II in human cardiac fibroblasts on the 3H-thymidine incorporation, the cell number, the 3H-leucine incorporation and the total protein content were measured. The expression of receptor mRNA was performed by reverse transcription-polymerase chain reaction (RT-PCR). Ang II increased 3H-leucine incorporation in a concentration-dependent manner but not 3H-thymidine incorporation in primary cultures of human cardiac fibroblasts. The maximum effect (24 +/- 3% over control) was obtained at a concentration of 10 nM. There were no significant alterations of cell number or total protein content, suggesting that Ang II stimulated protein synthesis but did not induce hypertrophy. The accumulation of 3H-leucine was blocked by the AT1 receptor antagonist candesartan but not by the AT2 receptor antagonist PD123319. By using RT-PCR, both AT1 and AT2 receptors mRNA were found to be expressed in human cardiac fibroblasts. The selective MAPKK inhibitor PD098059, the protein kinase C inhibitor K252a or the phospholipase C inhibitor U73122 did not significantly inhibit Ang II augmented 3H-leucine incorporation. However, this was significantly blocked by the Ca2+-dependent protein kinase C inhibitor GO6976, the non-selective protein kinase inhibitor staurosporine and the tyrosine kinase inhibitor tyrphostin 25. The effects of Ang II were unaffected by the Gi-protein blocker pertussis toxin, indicating a Gi-protein-independent pathway. Ang II was synergistic with insulin but showed no significant increase on 3H-leucine incorporation when combined with PDGF or EGF. In summary, Ang II stimulates protein synthesis through AT1 receptors in human cardiac fibroblasts, but has no hypertrophic or hyperplastic effect. The response is mediated by a MAPKK-independent and Ca2+-sensitive PKC-dependent pathway. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
PKC, MAPKK, human cardiac fibroblasts, angiotensin II, AT1 and AT2 receptors, RT-PCR, tyrosine kinase
in
Acta Physiologica Scandinavica
volume
168
issue
2
pages
301 - 309
publisher
Wiley-Blackwell
external identifiers
  • pmid:10712568
  • scopus:0034010299
ISSN
0001-6772
language
English
LU publication?
yes
id
80101353-c3ff-4a30-b53c-ccfe530dc06e (old id 1117328)
date added to LUP
2008-07-03 11:14:35
date last changed
2017-01-01 06:46:56
@article{80101353-c3ff-4a30-b53c-ccfe530dc06e,
  abstract     = {The aim of the present study was to investigate the proliferative effects of Ang II in human cardiac fibroblasts. The effects of Ang II in human cardiac fibroblasts on the 3H-thymidine incorporation, the cell number, the 3H-leucine incorporation and the total protein content were measured. The expression of receptor mRNA was performed by reverse transcription-polymerase chain reaction (RT-PCR). Ang II increased 3H-leucine incorporation in a concentration-dependent manner but not 3H-thymidine incorporation in primary cultures of human cardiac fibroblasts. The maximum effect (24 +/- 3% over control) was obtained at a concentration of 10 nM. There were no significant alterations of cell number or total protein content, suggesting that Ang II stimulated protein synthesis but did not induce hypertrophy. The accumulation of 3H-leucine was blocked by the AT1 receptor antagonist candesartan but not by the AT2 receptor antagonist PD123319. By using RT-PCR, both AT1 and AT2 receptors mRNA were found to be expressed in human cardiac fibroblasts. The selective MAPKK inhibitor PD098059, the protein kinase C inhibitor K252a or the phospholipase C inhibitor U73122 did not significantly inhibit Ang II augmented 3H-leucine incorporation. However, this was significantly blocked by the Ca2+-dependent protein kinase C inhibitor GO6976, the non-selective protein kinase inhibitor staurosporine and the tyrosine kinase inhibitor tyrphostin 25. The effects of Ang II were unaffected by the Gi-protein blocker pertussis toxin, indicating a Gi-protein-independent pathway. Ang II was synergistic with insulin but showed no significant increase on 3H-leucine incorporation when combined with PDGF or EGF. In summary, Ang II stimulates protein synthesis through AT1 receptors in human cardiac fibroblasts, but has no hypertrophic or hyperplastic effect. The response is mediated by a MAPKK-independent and Ca2+-sensitive PKC-dependent pathway.},
  author       = {Hou, M and Pantev, E and Moller, S and Erlinge, David and Edvinsson, Lars},
  issn         = {0001-6772},
  keyword      = {PKC,MAPKK,human cardiac fibroblasts,angiotensin II,AT1 and AT2 receptors,RT-PCR,tyrosine kinase},
  language     = {eng},
  number       = {2},
  pages        = {301--309},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Physiologica Scandinavica},
  title        = {Angiotensin II type 1 receptors stimulate protein synthesis in human cardiac fibroblasts via a Ca2+-sensitive PKC-dependent tyrosine kinase pathway},
  volume       = {168},
  year         = {2000},
}