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Journal ArticleDOI

Conversion of adult pancreatic α-cells to β-cells after extreme β-cell loss

22 Apr 2010-Nature (Nature Publishing Group)-Vol. 464, Iss: 7292, pp 1149-1154
TL;DR: In this article, a transgenic model of diphtheria-toxin-induced acute selective near-total beta-cell ablation was used to investigate whether adult mammals can differentiate (regenerate) new beta-cells after extreme, total β-cell loss, as in diabetes.
Abstract: Pancreatic insulin-producing beta-cells have a long lifespan, such that in healthy conditions they replicate little during a lifetime. Nevertheless, they show increased self-duplication after increased metabolic demand or after injury (that is, beta-cell loss). It is not known whether adult mammals can differentiate (regenerate) new beta-cells after extreme, total beta-cell loss, as in diabetes. This would indicate differentiation from precursors or another heterologous (non-beta-cell) source. Here we show beta-cell regeneration in a transgenic model of diphtheria-toxin-induced acute selective near-total beta-cell ablation. If given insulin, the mice survived and showed beta-cell mass augmentation with time. Lineage-tracing to label the glucagon-producing alpha-cells before beta-cell ablation tracked large fractions of regenerated beta-cells as deriving from alpha-cells, revealing a previously disregarded degree of pancreatic cell plasticity. Such inter-endocrine spontaneous adult cell conversion could be harnessed towards methods of producing beta-cells for diabetes therapies, either in differentiation settings in vitro or in induced regeneration.

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Citations
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Journal ArticleDOI
19 Aug 2011-Cell
TL;DR: It is shown that subpopulations of cells purified for a given phenotypic state return towards equilibrium proportions over time, and this findings contribute to the understanding of cancer heterogeneity and reveal how stochasticity in single-cell behaviors promotes phenotypesic equilibrium in populations of cancer cells.

1,391 citations

Journal ArticleDOI
14 Sep 2012-Cell
TL;DR: It is proposed that dedifferentiation trumps endocrine cell death in the natural history of β cell failure and suggested that treatment ofβ cell dysfunction should restore differentiation, rather than promoting β cell replication.

1,132 citations

Journal ArticleDOI
TL;DR: The transcription factor c‐Jun, although not required for Schwann cell development, is therefore central to the reprogramming of myelin and non‐myelin (Remak) Schwann cells to repair cells after injury.
Abstract: Nerve injury triggers the conversion of myelin and non-myelin (Remak) Schwann cells to a cell phenotype specialized to promote repair. Distal to damage, these repair Schwann cells provide the necessary signals and spatial cues for the survival of injured neurons, axonal regeneration and target reinnervation. The conversion to repair Schwann cells involves de-differentiation together with alternative differentiation, or activation, a combination that is typical of cell type conversions often referred to as (direct or lineage) reprogramming. Thus, injury-induced Schwann cell reprogramming involves down-regulation of myelin genes combined with activation of a set of repair-supportive features, including up-regulation of trophic factors, elevation of cytokines as part of the innate immune response, myelin clearance by activation of myelin autophagy in Schwann cells and macrophage recruitment, and the formation of regeneration tracks, Bungner's bands, for directing axons to their targets. This repair programme is controlled transcriptionally by mechanisms involving the transcription factor c-Jun, which is rapidly up-regulated in Schwann cells after injury. In the absence of c-Jun, damage results in the formation of a dysfunctional repair cell, neuronal death and failure of functional recovery. c-Jun, although not required for Schwann cell development, is therefore central to the reprogramming of myelin and non-myelin (Remak) Schwann cells to repair cells after injury. In future, the signalling that specifies this cell requires further analysis so that pharmacological tools that boost and maintain the repair Schwann cell phenotype can be developed.

728 citations

Journal ArticleDOI
TL;DR: Evidence that genetic and environmental factors can lead to hyperglycemia, dyslipidemia, inflammation, and autoimmunity, resulting in β-cell dysfunction, thereby triggering the pathogenesis of diabetes is presented.
Abstract: Pancreatic β-cell dysfunction plays an important role in the pathogenesis of both type 1 and type 2 diabetes. Insulin, which is produced in β-cells, is a critical regulator of metabolism. Insulin is synthesized as preproinsulin and processed to proinsulin. Proinsulin is then converted to insulin and C-peptide and stored in secretary granules awaiting release on demand. Insulin synthesis is regulated at both the transcriptional and translational level. The cis-acting sequences within the 5' flanking region and trans-activators including paired box gene 6 (PAX6), pancreatic and duodenal homeobox- 1(PDX-1), MafA, and β-2/Neurogenic differentiation 1 (NeuroD1) regulate insulin transcription, while the stability of preproinsulin mRNA and its untranslated regions control protein translation. Insulin secretion involves a sequence of events in β-cells that lead to fusion of secretory granules with the plasma membrane. Insulin is secreted primarily in response to glucose, while other nutrients such as free fatty acids and amino acids can augment glucose-induced insulin secretion. In addition, various hormones, such as melatonin, estrogen, leptin, growth hormone, and glucagon like peptide-1 also regulate insulin secretion. Thus, the β-cell is a metabolic hub in the body, connecting nutrient metabolism and the endocrine system. Although an increase in intracellular [Ca2+] is the primary insulin secretary signal, cAMP signaling- dependent mechanisms are also critical in the regulation of insulin secretion. This article reviews current knowledge on how β-cells synthesize and secrete insulin. In addition, this review presents evidence that genetic and environmental factors can lead to hyperglycemia, dyslipidemia, inflammation, and autoimmunity, resulting in β-cell dysfunction, thereby triggering the pathogenesis of diabetes.

712 citations

Journal ArticleDOI
TL;DR: Current research aims to understand how the processes of dedifferentiation, transdifferentiation or reprogramming work and to eventually harness them for use in regenerative medicine.
Abstract: The ultimate goal of regenerative medicine is to replace lost or damaged cells. This can potentially be accomplished using the processes of dedifferentiation, transdifferentiation or reprogramming. Recent advances have shown that the addition of a group of genes can not only restore pluripotency in a fully differentiated cell state (reprogramming) but can also induce the cell to proliferate (dedifferentiation) or even switch to another cell type (transdifferentiation). Current research aims to understand how these processes work and to eventually harness them for use in regenerative medicine.

607 citations

References
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Book
01 Jan 1986
TL;DR: Here are recorded the tech- niques for preparing, inserting and analysing DNA sequences, for retroviral infection of mice, for production and use of EC and EK cells as vehicles for engineered sequences and for nuclear transplantation - all against a background of the basic procedures required for pro- ducing and handling the em- bryos.
Abstract: Manipulating the Mouse Embryo: A Laboratory Manual by B. Hogan, F. Constantini and E. Lacy, Cold Spring Havi~ Laboratmy, 1986. $60.00 (332 pages) ISBN 0 87969 175 1 These are heady days for developmental biologists. Prob- lems that have puzzled scientists for centuries seem to be moving tom the realm of abstract philosophy towards practical solo ution. The power of recombinant DNA technology fuels this opti- mism; at last genes can be engineered, inserted, located, monitored, neutralized and their impact on development asses- sed. The prospect of interfering positively, rather than randomly, with the genetic basis for development is real. The prac- tical basis for this optimism, as recorded in this manual, is clearly well founded. It is impressive that so much pro- gress in the genetic manipulation of the mouse has been made so rapidly. Here are recorded the tech- niques for preparing, inserting and analysing DNA sequences, for retroviral infection of em- bryos, for production and use of EC and EK cells as vehicles for engineered sequences and for nuclear transplantation - all this against a background of the basic procedures required for pro- ducing and handling the em- bryos. If there is one critidsm, it is that the format and content of manual do reveal a fashionable, but perhaps a rather narrow, belief that it is by gene injection (or variants of it) alone that the problem of development will be solved. One might expect a laboratory manual entitled Manilmlating the Mouse Embryo to inform about more general practical aspects of mouse em- bryology than are contained here

5,615 citations

Journal ArticleDOI
TL;DR: In contrast to existing lacZ reporter lines, where lacZ expression cannot easily be detected in living tissue, the EYFP and ECFP reporter strains are useful for monitoring the expression of Cre and tracing the lineage of these cells and their descendants in cultured embryos or organs.
Abstract: Background Several Cre reporter strains of mice have been described, in which a lacZ gene is turned on in cells expressing Cre recombinase, as well as their daughter cells, following Cre-mediated excision of a loxP-flanked transcriptional "stop" sequence. These mice are useful for cell lineage tracing experiments as well as for monitoring the expression of Cre transgenes. The green fluorescent protein (GFP) and variants such as EYFP and ECFP offer an advantage over lacZ as a reporter, in that they can be easily visualized without recourse to the vital substrates required to visualize β-gal in living tissue.

2,941 citations

Journal ArticleDOI
06 May 2004-Nature
TL;DR: This work introduces a method for genetic lineage tracing to determine the contribution of stem cells to a tissue of interest and suggests that terminally differentiated β-cells retain a significant proliferative capacity in vivo and casts doubt on the idea that adult stem cells have a significant role in β-cell replenishment.
Abstract: How tissues generate and maintain the correct number of cells is a fundamental problem in biology. In principle, tissue turnover can occur by the differentiation of stem cells, as is well documented for blood, skin and intestine, or by the duplication of existing differentiated cells. Recent work on adult stem cells has highlighted their potential contribution to organ maintenance and repair. However, the extent to which stem cells actually participate in these processes in vivo is not clear. Here we introduce a method for genetic lineage tracing to determine the contribution of stem cells to a tissue of interest. We focus on pancreatic beta-cells, whose postnatal origins remain controversial. Our analysis shows that pre-existing beta-cells, rather than pluripotent stem cells, are the major source of new beta-cells during adult life and after pancreatectomy in mice. These results suggest that terminally differentiated beta-cells retain a significant proliferative capacity in vivo and cast doubt on the idea that adult stem cells have a significant role in beta-cell replenishment.

2,103 citations

Journal ArticleDOI
02 Oct 2008-Nature
TL;DR: This study identifies a specific combination of three transcription factors (Ngn3) Pdx1 and Mafa that reprograms differentiated pancreatic exocrine cells in adult mice into cells that closely resemble β-cells, and suggests a general paradigm for directing cell reprogramming without reversion to a pluripotent stem cell state.
Abstract: One goal of regenerative medicine is to instructively convert adult cells into other cell types for tissue repair and regeneration. Although isolated examples of adult cell reprogramming are known, there is no general understanding of how to turn one cell type into another in a controlled manner. Here, using a strategy of re-expressing key developmental regulators in vivo, we identify a specific combination of three transcription factors (Ngn3 (also known as Neurog3) Pdx1 and Mafa) that reprograms differentiated pancreatic exocrine cells in adult mice into cells that closely resemble beta-cells. The induced beta-cells are indistinguishable from endogenous islet beta-cells in size, shape and ultrastructure. They express genes essential for beta-cell function and can ameliorate hyperglycaemia by remodelling local vasculature and secreting insulin. This study provides an example of cellular reprogramming using defined factors in an adult organ and suggests a general paradigm for directing cell reprogramming without reversion to a pluripotent stem cell state.

1,990 citations

Journal ArticleDOI
01 Dec 1999-Diabetes
TL;DR: It is reported that exendin-4, a long-acting GLP-I agonist, stimulates both the differentiation of beta-cells from ductal progenitor cells (neogenesis) and proliferation of Beta-cells when administered to rats and holds promise as a novel therapy to stimulate beta-cell growth and differentiation when administer to diabetic individuals with reduced beta- cell mass.
Abstract: Diabetes is a disease of increasing prevalence in the general population and of unknown cause. Diabetes is manifested as hyperglycemia due to a relative deficiency of the production of insulin by the pancreatic beta-cells. One determinant in the development of diabetes is an inadequate mass of beta-cells, either absolute (type 1, juvenile diabetes) or relative (type 2, maturity-onset diabetes). Earlier, we reported that the intestinal hormone glucagon-like peptide I (GLP-I) effectively augments glucose-stimulated insulin secretion. Here we report that exendin-4, a long-acting GLP-I agonist, stimulates both the differentiation of beta-cells from ductal progenitor cells (neogenesis) and proliferation of beta-cells when administered to rats. In a partial pancreatectomy rat model of type 2 diabetes, the daily administration of exendin-4 for 10 days post-pancreatectomy attenuates the development of diabetes. We show that exendin-4 stimulates the regeneration of the pancreas and expansion of beta-cell mass by processes of both neogenesis and proliferation of beta-cells. Thus, GLP-I and analogs thereof hold promise as a novel therapy to stimulate beta-cell growth and differentiation when administered to diabetic individuals with reduced beta-cell mass.

1,253 citations

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