title: Expansion of adult beta-cell mass in response to increased metabolic demand is dependent on HNF-4alpha.
abstract: The failure to expand functional pancreatic beta-cell mass in response to increased metabolic demand is a hallmark of type 2 diabetes. Lineage tracing studies indicate that replication of existing beta-cells is the principle mechanism for beta-cell expansion in adult mice. Here we demonstrate that the proliferative response of beta-cells is dependent on the orphan nuclear receptor hepatocyte nuclear factor-4alpha (HNF-4alpha), the gene that is mutated in Maturity-Onset Diabetes of the Young 1 (MODY1). Computational analysis of microarray expression profiles from isolated islets of mice lacking HNF-4alpha in pancreatic beta-cells reveals that HNF-4alpha regulates selected genes in the beta-cell, many of which are involved in proliferation. Using a physiological model of beta-cell expansion, we show that HNF-4alpha is required for beta-cell replication and the activation of the Ras/ERK signaling cascade in islets. This phenotype correlates with the down-regulation of suppression of tumorigenicity 5 (ST5) in HNF-4alpha mutants, which we identify as a novel regulator of ERK phosphorylation in beta-cells and a direct transcriptional target of HNF-4alpha in vivo. Together, these results indicate that HNF-4alpha is essential for the physiological expansion of adult beta-cell mass in response to increased metabolic demand.
authors.affiliation: Department of Genetics and Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Rana K
authors.initials: RK
authors.lastname: Gupta
authors.forename: Nan
authors.initials: N
authors.lastname: Gao
authors.forename: Regina K
authors.initials: RK
authors.lastname: Gorski
authors.forename: Peter
authors.initials: P
authors.lastname: White
authors.forename: Olga T
authors.initials: OT
authors.lastname: Hardy
authors.forename: Kiran
authors.initials: K
authors.lastname: Rafiq
authors.forename: John E
authors.initials: JE
authors.lastname: Brestelli
authors.forename: Guang
authors.initials: G
authors.lastname: Chen
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Stoeckert
authors.forename: Klaus H
authors.initials: KH
authors.lastname: Kaestner
mesh_terms: D000818:Animals; D001483:Base Sequence; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D051557:Hepatocyte Nuclear Factor 4 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011247:Pregnancy; D015398:Signal Transduction / Q000235:genetics; D014158:Transcription, Genetic; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; C486188:St5 protein, mouse; D025521:Tumor Suppressor Proteins; D048049:Extracellular Signal-Regulated MAP Kinases; D018631:ras Proteins