Bone morphogenetic protein 3 controls insulin gene expression and is down-regulated in INS-1 cells inducibly expressing a hepatocyte nuclear factor 1A-maturity-onset diabetes of the young mutation.
Inactivating mutations in the transcription factor hepatocyte nuclear factor (HNF) 1A cause HNF1A-maturity-onset diabetes of the young (HNF1A-MODY), the most common monogenic form of diabetes. To examine HNF1A-MODY-induced defects in gene expression, we performed a microarray analysis of the transcriptome of rat INS-1 cells inducibly expressing the common hot spot HNF1A frameshift mutation, Pro291fsinsC-HNF1A. Real-time quantitative PCR (qPCR), Western blotting, immunohistochemistry, reporter assays, and chromatin immunoprecipitation (ChIP) were used to validate alterations in gene expression and to explore biological activities of target genes. Twenty-four hours after induction of the mutant HNF1A protein, we identified a prominent down-regulation of the bone morphogenetic protein 3 gene (Bmp-3) mRNA expression. Reporter assays, qPCR, and Western blot analysis validated these results. In contrast, inducible expression of wild-type HNF1A led to a time-dependent increase in Bmp-3 mRNA and protein levels. Moreover, reduced protein levels of BMP-3 and insulin were detected in islets of transgenic HNF1A-MODY mice. Interestingly, treatment of naïve INS-1 cells or murine organotypic islet cultures with recombinant human BMP-3 potently increased their insulin levels and restored the decrease in SMAD2 phosphorylation and insulin gene expression induced by the HNF1A frameshift mutation. Our study suggests a critical link between HNF1A-MODY-induced alterations in Bmp-3 expression and insulin gene levels in INS-1 cells and indicates that the reduced expression of growth factors involved in tissue differentiation may play an important role in the pathophysiology of HNF1A-MODY.
This work was supported by Health Research Board Grant RP/2008/14 and Science Foundation Ireland Grant 08/IN1/1949 (to J. H. M. P.) and Health Research Board Grants RP/2004/220 and RP/2007/316 (to M. M. B.).
CommentsThis article is also available at http://www.jbc.org/content/286/29/25719.full.pdf
Published CitationBonner C, Farrelly AM, Concannon CG, Dussmann H, Baquié M, Virard I, Wobser H, Kögel D, Wollheim CB, Rupnik M, Byrne MM, König HG, Prehn JH. Bone morphogenetic protein 3 controls insulin gene expression and is down-regulated in INS-1 cells inducibly expressing a hepatocyte nuclear factor 1A-maturity-onset diabetes of the young mutation. Journal of Biological Chemistry. 2011;286(29):25719-28.
- Physiology and Medical Physics