Low Doses of EPO Activate MAP Kinases but Not JAK2–STAT5 in Rat Vascular Smooth Muscle Cells
Issue date
2001Suggested citation
Ammarguellat, Fatima;
Llovera i Tomàs, Marta;
Kelly, Paul A.;
Goffin, Vincent;
.
(2001)
.
Low Doses of EPO Activate MAP Kinases but Not JAK2–STAT5 in Rat Vascular Smooth Muscle Cells.
Biochemical and Biophysical Research Communications, 2001, vol. 284, núm. 4, p. 1031-1038.
https://doi.org/10.1006/bbrc.2001.5085.
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Show full item recordAbstract
Previous reports have shown a direct effect of erythropoietin
(Epo) on vascular smooth muscle cells
(VSMCs). Our aim was to assess expression of the Epo
receptor (EpoR) on VSMCs and to study the activation
of two major signaling cascades activated by Epo,
namely JAK2/STAT5 and MAPK pathways. All experiments
were performed in parallel using the Eporesponsive
UT7 cell line. From semiquantitative RTPCR
experiments, VSMCs were estimated to express
;30-fold less EpoR mRNA than UT7 cells. Epo-induced
phosphorylation of proteins involved in the EpoR/
JAK2/STAT5 cascade could not be detected in VSMCs,
even using pharmacological doses of Epo (250 IU/ml).
In contrast, a strong activation of MAP kinase pathway
was detected with as low as 10 IU/ml Epo. We
suggest that MAPK activation reflects a physiologically
relevant effect of Epo on VSMCs that may be
correlated to cell proliferation.