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Characterisation of receptors for IGF-I and insulin; evidence for hybrid insulin/IGF-I receptor in human coronary artery endothelial cells

Chisalita, Simona I ; Dekker Nitert, Marloes LU and Arnqvist, Hans J (2006) In Growth Hormone & Igf Research 16(4). p.258-266
Abstract
OBJECTIVE: Coronary artery disease is a prevalent cause of morbidity and mortality in diabetes. Little is known about insulin-like growth factor-I receptors (IGF-IR) and insulin receptors (IR) in human coronary endothelium. Our aim was to characterize IGF-IR and IR in human coronary artery endothelial cells (HCAEC). DESIGN: Cultured human coronary artery endothelial cells were used. Gene expression was measured by quantitative real-time RT-PCR analysis and receptor affinity by ligand binding. Receptor protein, phosphorylation of IGF-IR and IR beta-subunit as well as the presence of hybrid insulin receptor/Insulin-like growth factor-I receptor (Hybrid IR/IGF-IR) was analyzed by immunoprecipitation and Western blot. Postreceptor effects of... (More)
OBJECTIVE: Coronary artery disease is a prevalent cause of morbidity and mortality in diabetes. Little is known about insulin-like growth factor-I receptors (IGF-IR) and insulin receptors (IR) in human coronary endothelium. Our aim was to characterize IGF-IR and IR in human coronary artery endothelial cells (HCAEC). DESIGN: Cultured human coronary artery endothelial cells were used. Gene expression was measured by quantitative real-time RT-PCR analysis and receptor affinity by ligand binding. Receptor protein, phosphorylation of IGF-IR and IR beta-subunit as well as the presence of hybrid insulin receptor/Insulin-like growth factor-I receptor (Hybrid IR/IGF-IR) was analyzed by immunoprecipitation and Western blot. Postreceptor effects of insulin and IGF-I were assed by (3)H-thymidine incorporation. RESULTS: The gene expression of IGF-IR was several folds higher than that of IR. and insulin receptor isoform A (IR-A) was 20-fold more expressed than insulin receptor isoform B (IR-B) in HCAEC. The specific binding of (125)I-IGF-I was higher than that of (125)I-insulin. Insulin and the new long acting insulin analog, glargine, interacted with the IGF-IR with over thousand and 100-fold less potency than IGF-I itself, whereas IGF-II had 6 times lower potency than IGF-I. Phosphorylation of the IGF-IR beta-subunit was obtained by concentrations of 10(-10)-10(-8)M IGF-I, 10(-6)M of insulin, inconsistently by 10(-8)M insulin and not at all by 10(-10)-10(-9)M insulin. The IR beta-subunit was phosphorylated by insulin and IGF-I at concentrations of 10(-9)-10(-8)M. When immunoprecipitating with specific monoclonal anti-IR or anti-IGF-IR alpha-subunit antibodies we found bands situated in slightly different positions suggesting the presence of Hybrid IR/IGF-IR. IGF-I, IGF-II and insulin (10(-9)-10(-7)M) had no significant effect on (3)H-thymidine incorporation into DNA. CONCLUSIONS: Human coronary endothelial cells express more IGF-IR than IR, mainly IR-A, and also Hybrid IR/IGF-IR. Both IGF-I and insulin phosphorylate their receptors, but only IGF-I seems to phosphorylate Hybrid IR/IGF-IR. Our study provides experimental evidence for a possible role of IGF-IR, IR and Hybrid IR/IGF-IR in human coronary artery endothelial cells. (Less)
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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Human endothelial cells, Insulin-like growth factor-I, Insulin
in
Growth Hormone & Igf Research
volume
16
issue
4
pages
258 - 266
publisher
Elsevier
external identifiers
  • pmid:16914341
  • scopus:33748169659
  • pmid:16914341
ISSN
1532-2238
DOI
10.1016/j.ghir.2006.06.003
language
English
LU publication?
yes
additional info
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Molecular Metabolism (013212001)
id
7fdd0868-56e2-421f-b062-235a9f202635 (old id 1137365)
date added to LUP
2016-04-01 11:58:03
date last changed
2022-01-26 20:54:58
@article{7fdd0868-56e2-421f-b062-235a9f202635,
  abstract     = {{OBJECTIVE: Coronary artery disease is a prevalent cause of morbidity and mortality in diabetes. Little is known about insulin-like growth factor-I receptors (IGF-IR) and insulin receptors (IR) in human coronary endothelium. Our aim was to characterize IGF-IR and IR in human coronary artery endothelial cells (HCAEC). DESIGN: Cultured human coronary artery endothelial cells were used. Gene expression was measured by quantitative real-time RT-PCR analysis and receptor affinity by ligand binding. Receptor protein, phosphorylation of IGF-IR and IR beta-subunit as well as the presence of hybrid insulin receptor/Insulin-like growth factor-I receptor (Hybrid IR/IGF-IR) was analyzed by immunoprecipitation and Western blot. Postreceptor effects of insulin and IGF-I were assed by (3)H-thymidine incorporation. RESULTS: The gene expression of IGF-IR was several folds higher than that of IR. and insulin receptor isoform A (IR-A) was 20-fold more expressed than insulin receptor isoform B (IR-B) in HCAEC. The specific binding of (125)I-IGF-I was higher than that of (125)I-insulin. Insulin and the new long acting insulin analog, glargine, interacted with the IGF-IR with over thousand and 100-fold less potency than IGF-I itself, whereas IGF-II had 6 times lower potency than IGF-I. Phosphorylation of the IGF-IR beta-subunit was obtained by concentrations of 10(-10)-10(-8)M IGF-I, 10(-6)M of insulin, inconsistently by 10(-8)M insulin and not at all by 10(-10)-10(-9)M insulin. The IR beta-subunit was phosphorylated by insulin and IGF-I at concentrations of 10(-9)-10(-8)M. When immunoprecipitating with specific monoclonal anti-IR or anti-IGF-IR alpha-subunit antibodies we found bands situated in slightly different positions suggesting the presence of Hybrid IR/IGF-IR. IGF-I, IGF-II and insulin (10(-9)-10(-7)M) had no significant effect on (3)H-thymidine incorporation into DNA. CONCLUSIONS: Human coronary endothelial cells express more IGF-IR than IR, mainly IR-A, and also Hybrid IR/IGF-IR. Both IGF-I and insulin phosphorylate their receptors, but only IGF-I seems to phosphorylate Hybrid IR/IGF-IR. Our study provides experimental evidence for a possible role of IGF-IR, IR and Hybrid IR/IGF-IR in human coronary artery endothelial cells.}},
  author       = {{Chisalita, Simona I and Dekker Nitert, Marloes and Arnqvist, Hans J}},
  issn         = {{1532-2238}},
  keywords     = {{Human endothelial cells; Insulin-like growth factor-I; Insulin}},
  language     = {{eng}},
  number       = {{4}},
  pages        = {{258--266}},
  publisher    = {{Elsevier}},
  series       = {{Growth Hormone & Igf Research}},
  title        = {{Characterisation of receptors for IGF-I and insulin; evidence for hybrid insulin/IGF-I receptor in human coronary artery endothelial cells}},
  url          = {{http://dx.doi.org/10.1016/j.ghir.2006.06.003}},
  doi          = {{10.1016/j.ghir.2006.06.003}},
  volume       = {{16}},
  year         = {{2006}},
}