Animals, Bone Morphogenetic Protein 3, Cell Line, Tumor, Down-Regulation, Frameshift Mutation, Gene Expression Profiling, Hepatocyte Nuclear Factor 1-alpha, Humans, Insulin, Insulin-Secreting Cells, Mice, Oligonucleotide Array Sequence Analysis, Promoter Regions, Genetic, Rats
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.).
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.
Physics | Physiology
Bonner 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.
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