The importance of the insulin receptor (IR) and the insulin-like growth factor-1 receptor (IGF-1R) for glucose-regulated insulin secretion and gene expression in pancreatic islet β-cells is at present unresolved. Here, we have used small interfering RNAs (siRNAs) to silence the expression of each receptor selectively in clonal MIN6 β-cells. Reduction of IR levels by >90% completely inhibited glucose (30 mM compared with 3 mM)-induced insulin secretion, but had no effect on depolarization-stimulated secretion. IR depletion also blocked the accumulation of preproinsulin (PPI), pancreatic duodenum homoeobox-1 (PDX-1) and glucokinase (GK) mRNAs at elevated glucose concentrations, as assessed by quantitative real-time PCR analysis (TaqMan®). Similarly, depletion of IGF-1R inhibited glucose-induced insulin secretion but, in contrast with the effects of IR silencing, had little impact on the regulation of gene expression by glucose. Moreover, loss of IGF-1R, but not IR, markedly inhibited glucose-stimulated increases in cytosolic and mitochondrial ATP, suggesting a role for IGF-1R in the maintenance of oxidative metabolism and in the generation of mitochondrial coupling factors. RNA silencing thus represents a useful tool for the efficient and selective inactivation of receptor tyrosine kinases in isolated β-cells. By inhibiting glucose-stimulated insulin secretion through the inactivation of IGF-1R, this approach also demonstrates the existence of insulin-independent mechanisms whereby elevated glucose concentrations regulate PPI, PDX-1 and GK gene expression in β-cells.
Skip Nav Destination
Article navigation
January 2004
- PDF Icon PDF LinkFront Matter
Research Article|
January 01 2004
Distinct roles for insulin and insulin-like growth factor-1 receptors in pancreatic beta-cell glucose sensing revealed by RNA silencing
Gabriela da SILVA XAVIER;
Gabriela da SILVA XAVIER
1
Henry Wellcome Laboratories for Integrated Cell Signalling and Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, U.K.
Search for other works by this author on:
Qingwen QIAN;
Qingwen QIAN
1
Henry Wellcome Laboratories for Integrated Cell Signalling and Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, U.K.
Search for other works by this author on:
Peter J. CULLEN;
Peter J. CULLEN
Henry Wellcome Laboratories for Integrated Cell Signalling and Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, U.K.
Search for other works by this author on:
Guy A. RUTTER
Guy A. RUTTER
2
Henry Wellcome Laboratories for Integrated Cell Signalling and Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, U.K.
2To whom correspondence should be addressed (e-mail G.A.Rutter@bristol.ac.uk).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
August 18 2003
Revision Received:
October 15 2003
Accepted:
October 17 2003
Accepted Manuscript online:
October 17 2003
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London ©2004
2004
Biochem J (2004) 377 (1): 149–158.
Article history
Received:
August 18 2003
Revision Received:
October 15 2003
Accepted:
October 17 2003
Accepted Manuscript online:
October 17 2003
Connected Content
A correction has been published:
Distinct roles for insulin and insulin-like growth factor-1 receptors in pancreatic β-cell glucose sensing revealed by RNA silencing
Citation
Gabriela da SILVA XAVIER, Qingwen QIAN, Peter J. CULLEN, Guy A. RUTTER; Distinct roles for insulin and insulin-like growth factor-1 receptors in pancreatic beta-cell glucose sensing revealed by RNA silencing. Biochem J 1 January 2004; 377 (1): 149–158. doi: https://doi.org/10.1042/bj20031260
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.