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Craig Dorrell,
Laura Erker,
Jonathan Schug,
Janel L Kopp,
Pamela S Canaday, Alan J Fox,
Olga Smirnova,
Andrew W Duncan,
Milton J Finegold,
Maike Sander,
Klaus H Kaestner,
Markus Grompe
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ABSTRACT: The molecular identification of adult hepatic stem/progenitor cells has been hampered by the lack of truly specific markers. To isolate putative adult liver progenitor cells, we used cell surface-marking antibodies, including MIC1-1C3, to isolate subpopulations of liver cells from normal adult mice or those undergoing an oval cell response and tested their capacity to form bilineage colonies in vitro. Robust clonogenic activity was found to be restricted to a subset of biliary duct cells antigenically defined as CD45(-)/CD11b(-)/CD31(-)/MIC1-1C3(+)/CD133(+)/CD26(-), at a frequency of one of 34 or one of 25 in normal or oval cell injury livers, respectively. Gene expression analyses revealed that Sox9 was expressed exclusively in this subpopulation of normal liver cells and was highly enriched relative to other cell fractions in injured livers. In vivo lineage tracing using Sox9creER(T2)-R26R(YFP) mice revealed that the cells that proliferate during progenitor-driven liver regeneration are progeny of Sox9-expressing precursors. A comprehensive array-based comparison of gene expression in progenitor-enriched and progenitor-depleted cells from both normal and DDC (3,5-diethoxycarbonyl-1,4-dihydrocollidine or diethyl1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate)-treated livers revealed new potential regulators of liver progenitors.
Genes & development 06/2011; 25(11):1193-203. · 12.08 Impact Factor
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ABSTRACT: Foxa1 and Foxa2 play both redundant and distinct roles in early pancreas development. We demonstrate here that inducible ablation of both transcription factors in mature mouse beta-cells leads to impaired glucose homeostasis and insulin secretion. The defects in both glucose-stimulated insulin secretion and intracellular calcium oscillation are more pronounced than those in beta-cells lacking only Foxa2. Unexpectedly, in contrast to the severe reduction of beta-cell-enriched factors contributing to metabolic and secretory pathways, expression of a large number of genes that are involved in neural differentiation and function is significantly elevated. We further demonstrate that expression of carbohydrate response element-binding protein (ChREBP or Mlxipl), an important transcriptional regulator of carbohydrate metabolism, is significantly affected in compound Foxa1/a2 mutant beta-cells. ChREBP expression is directly controlled by Foxa1 and Foxa2 in both the fetal endocrine pancreas as well as mature islets. These data demonstrate that Foxa1 and Foxa2 play crucial roles in the development and maintenance of beta-cell-specific secretory and metabolic pathways.
Molecular Endocrinology 08/2010; 24(8):1594-604. · 4.54 Impact Factor
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Sebastian Rieck,
Peter White,
Jonathan Schug, Alan J Fox,
Olga Smirnova,
Nan Gao,
Rana K Gupta,
Zhao V Wang,
Philipp E Scherer,
Mark P Keller,
Alan D Attie,
Klaus H Kaestner
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ABSTRACT: The inability of the ss-cell to meet the demand for insulin brought about by insulin resistance leads to type 2 diabetes. In adults, ss-cell replication is one of the mechanisms thought to cause the expansion of ss-cell mass. Efforts to treat diabetes require knowledge of the pathways that drive facultative ss-cell proliferation in vivo. A robust physiological stimulus of ss-cell expansion is pregnancy and identifying the mechanisms underlying this stimulus may provide therapeutic leads for the treatment of type 2 diabetes. The peak in ss-cell proliferation during pregnancy occurs on d 14.5 of gestation in mice. Using advanced genomic approaches, we globally characterize the gene expression signature of pancreatic islets on d 14.5 of gestation during pregnancy. We identify a total of 1907 genes as differentially expressed in the islet during pregnancy. The islet's ability to compensate for relative insulin deficiency during metabolic stress is associated with the induction of both proliferative and survival pathways. A comparison of the genes induced in three different models of islet expansion suggests that diverse mechanisms can be recruited to expand islet mass. The identification of many novel genes involved in islet expansion during pregnancy provides an important resource for diabetes researchers to further investigate how these factors contribute to the maintenance of not only islet mass, but ultimately ss-cell mass.
Molecular Endocrinology 08/2009; 23(10):1702-12. · 4.54 Impact Factor
