The EndoC-βH1 cell line is a valid model of human beta cells and applicable for screenings to identify novel drug target candidates.

Objective: To characterize the EndoC-βH1 cell line as a model for human beta cells and evaluate its beta cell functionality, focusing on insulin secretion, proliferation, apoptosis and ER stress, with the objective to assess its potential as a screening platform for identification of novel anti-diabetic drug candidates.

Methods: EndoC-βH1 was transplanted into mice for validation of in vivo functionality. Insulin secretion was evaluated in cells cultured as monolayer and as pseudoislets, as well as in diabetic mice.

Pancreatic α-cell hyperplasia and hyperglucagonemia due to a glucagon receptor splice mutation.

Unlabelled: Glucagon stimulates hepatic glucose production by activating specific glucagon receptors in the liver, which in turn increase hepatic glycogenolysis as well as gluconeogenesis and ureagenesis from amino acids. Conversely, glucagon secretion is regulated by concentrations of glucose and amino acids. Disruption of glucagon signaling in rodents results in grossly elevated circulating glucagon levels but no hypoglycemia.

Long-Term GABA Administration Induces Alpha Cell-Mediated Beta-like Cell Neogenesis.

The recent discovery that genetically modified α cells can regenerate and convert into β-like cells in vivo holds great promise for diabetes research. However, to eventually translate these findings to human, it is crucial to discover compounds with similar activities. Herein, we report the identification of GABA as an inducer of α-to-β-like cell conversion in vivo.

Xenotropic retrovirus Bxv1 in human pancreatic β cell lines.

It has been reported that endogenous retroviruses can contaminate human cell lines that have been passaged as xenotransplants in immunocompromised mice. We previously developed and described 2 human pancreatic β cell lines (EndoC-βH1 and EndoC-βH2) that were generated in this way. Here, we have shown that B10 xenotropic virus 1 (Bxv1), a xenotropic endogenous murine leukemia virus (MuLV), is present in these 2 recently described cell lines.

Research Resource: A Dual Proteomic Approach Identifies Regulated Islet Proteins During β-Cell Mass Expansion In Vivo.

Diabetes is characterized by insulin insufficiency due to a relative paucity of functional β-cell mass. Thus, strategies for increasing β-cell mass in situ are sought-after for therapeutic purposes. Pregnancy is a physiological state capable of inducing robust β-cell mass expansion, however, the mechanisms driving this expansion are not fully understood.

Autocrine Action of IGF2 Regulates Adult β-Cell Mass and Function.

Insulin-like growth factor 2 (IGF2), produced and secreted by adult β-cells, functions as an autocrine activator of the β-cell insulin-like growth factor 1 receptor signaling pathway. Whether this autocrine activity of IGF2 plays a physiological role in β-cell and whole-body physiology is not known. Here, we studied mice with β-cell-specific inactivation of Igf2 (βIGF2KO mice) and assessed β-cell mass and function in aging, pregnancy, and acute induction of insulin resistance.

Analysis artefacts of the INS-IGF2 fusion transcript.

Background: In gene expression analysis, overlapping genes, splice variants, and fusion transcripts are potential sources of data analysis artefacts, depending on how the observed intensity is assigned to one, or more genes. We here exemplify this by an in-depth analysis of the INS-IGF2 fusion transcript, which has recently been reported to be among the highest expressed transcripts in human pancreatic beta cells and its protein indicated as a novel autoantigen in Type 1 Diabetes.

Results: Through RNA sequencing and variant specific qPCR analyses we demonstrate that the true abundance of INS-IGF2 is >20,000 fold lower than INS in human beta cells, and we suggest an explanation to the nature of the artefacts which have previously led to overestimation of the gene expression level in selected studies.

Betatrophin.

Regenerative therapy in diabetes with the capacity to reconstitute a functional β-cell mass sufficient for glycemic control holds the promise to effectively prevent the development of devastating late complications due to the unique ability of the β-cell to sense and regulate blood-glucose levels. An ability that cannot be mimicked by insulin replacement therapy or any other means of current treatment regiments for very large patient populations. Recently, Douglas A.

Beta cell workshop 2013 Kyoto.

The very modern Kyoto International Conference Center provided the site for the 8th workshop on Beta cells on April 23-26, 2013. The preceding workshops were held in Boston, USA (1991); Kyoto, Japan (1994); Helsingør, Denmark (1997); Helsinki, Finland (2003); El Perello, Spain (2006); Peebles, Scotland (2009); and Helsingør, Denmark (2011). The Kyoto meeting drew more than 200 attendees from 18 different countries.

Ptf1a-mediated control of Dll1 reveals an alternative to the lateral inhibition mechanism.

Neurog3-induced Dll1 expression in pancreatic endocrine progenitors ostensibly activates Hes1 expression via Notch and thereby represses Neurog3 and endocrine differentiation in neighboring cells by lateral inhibition. Here we show in mouse that Dll1 and Hes1 expression deviate during regionalization of early endoderm, and later during early pancreas morphogenesis. At that time, Ptf1a activates Dll1 in multipotent pancreatic progenitor cells (MPCs), and Hes1 expression becomes Dll1 dependent over a brief time window.

Intracranial ectopic pancreatic tissue.

In 2007 a young Japanese female was reported to suffer from a congenital brain malformation with a non-functioning pancreatic endocrine tumor arising from intracranial ectopic pancreatic tissue. Ectopic pancreas is normally confined to other endodermally-derived organs and not previously reported to be found in the brain. Therefore, we sought to better understand the true pancreatic nature of the tissue and to further understand the mechanism by which ectopic pancreas could appear in the brain.

[From stem cells to functional beta cells in type 1 diabetes].

Although the reconstitution of a functional β-cell mass by transplantation of isolated islets can restore euglycaemia in the absence of insulin treatment, a shortage of donor material is preventing the use of cell replacement therapy for treatment of type 1 diabetes. Advances in directed differentiation of stem cells towards β-cells via stepwise recapitulation of embryonic development demonstrate that stem cells may be an appropriate source for the generation of therapeutic cells. In the present article, we highlight some of the critical issues impeding the translation of stem cell-based therapies to the clinic.

Pluripotent stem cells, a potential source of beta-cells for diabetes therapy.

Although the reconstitution of a functional beta-cell mass by transplantation of isolated islets can restore euglycemia in the absence of insulin treatment, a shortage of donor material is one of the factors preventing the general use of cell replacement therapy for the treatment of type 1 diabetes mellitus (T1DM). Advances in the directed differentiation of pluripotent stem cells toward beta-cells via the stepwise recapitulation of embryonic development have generated proof of concept demonstrating that stem cells may be an appropriate source of cells for the generation of therapeutic beta-cells. However, progress toward a clinical application of this technology is slow and challenging.

The ectopic expression of Pax4 in the mouse pancreas converts progenitor cells into alpha and subsequently beta cells.

We have previously reported that the loss of Arx and/or Pax4 gene activity leads to a shift in the fate of the different endocrine cell subtypes in the mouse pancreas, without affecting the total endocrine cell numbers. Here, we conditionally and ectopically express Pax4 using different cell-specific promoters and demonstrate that Pax4 forces endocrine precursor cells, as well as mature alpha cells, to adopt a beta cell destiny. This results in a glucagon deficiency that provokes a compensatory and continuous glucagon+ cell neogenesis requiring the re-expression of the proendocrine gene Ngn3.

G protein-coupled receptor 39 deficiency is associated with pancreatic islet dysfunction.

G protein-coupled receptor (GPR)-39 is a seven-transmembrane receptor expressed mainly in endocrine and metabolic tissues that acts as a Zn(++) sensor signaling mainly through the G(q) and G(12/13) pathways. The expression of GPR39 is regulated by hepatocyte nuclear factor (HNF)-1alpha and HNF-4alpha, and in the present study, we addressed the importance of GPR39 for glucose homeostasis and pancreatic islets function. The expression and localization of GPR39 were characterized in the endocrine pancreas and pancreatic cell lines.

The morphology of islets of Langerhans is only mildly affected by the lack of Pdx-1 in the pancreas of adult Meriones jirds.

The Meriones Jirds belong to the genus of Gerbillinae (Rodentia: Muridae). We and others have previously reported the lack of the pancreatic beta-cell transcription factor, Pdx-1 in the fat sand rat, Psammomys obesus. The aim of the study was to investigate the expression and localization of Pdx-1 in phylogenetically related members of the Gerbillinae subfamily.

Investigation and characterization of the duct cell-enriching process during serum-free suspension and monolayer culture using the human exocrine pancreas fraction.

Objectives: We aimed to characterize a serum-free culture system resulting in highly enriched duct cells from human exocrine pancreas. In addition, we tested the effect of vascular endothelial growth factor (VEGF) on endothelial cell proliferation and endocrine differentiation of the duct cells.

Methods: The exocrine pellet fraction was cultivated in suspension followed by monolayer culture.

Generation and characterization of Ptf1a antiserum and localization of Ptf1a in relation to Nkx6.1 and Pdx1 during the earliest stages of mouse pancreas development.

Ptf1a and Pdx1 are critical transcription factors of early pancreatic development, as shown by loss of function studies where lack of each gene alone causes almost complete pancreas agenesis. Ptf1a is particularly interesting because it is linked to a recently reported signature gene expression profile associated with the multipotent condition. Few useful antibody reagents have been available for consistent and reliable immunohistochemical visualization of Ptf1a protein expression in the early developing pancreas in which the level of production of this critical regulator seems to be very low.

Specificity of four monoclonal anti-NKx6-1 antibodies.

The homeodomain transcription factor Nkx6-1 is essential for proper motor neuron development and development of insulin-producing pancreatic beta-cells. Nkx6-1 is closely related to Nkx6-2 and Nkx6-3, and all three are expressed in the developing central nervous system and in the developing foregut. Immunohistochemical detection of protein expression is an important tool for description of the temporal differences in expression patterns.

An illustrated review of early pancreas development in the mouse.

Pancreas morphogenesis and cell differentiation are highly conserved among vertebrates during fetal development. The pancreas develops through simple budlike structures on the primitive gut tube to a highly branched organ containing many specialized cell types. This review presents an overview of key molecular components and important signaling sources illustrated by an extensive three-dimensional (3D) imaging of the developing mouse pancreas at single cell resolution.

Pancreas phylogeny and ontogeny in relation to a 'pancreatic stem cell'.

Blood glucose regulation has likely evolved during early vertebrate evolution to allow and secure the concurrent evolution of complex brains and nervous systems: an inner milieu of constant blood glucose levels through millions of years has provided an extra degree of freedom for the brain to evolve without having to think of getting energy supply. Key regulators of blood glucose, insulin, and glucagon are produced by the dominating cell types of the pancreatic islet of Langerhans: the insulin producing beta cells and the glucagon producing alpha cells. Interestingly, it appears that the beta cell pioneered the formation or the foundation of the pancreatic organ according to current phylogenetic insights.

An improved method for three-dimensional reconstruction of protein expression patterns in intact mouse and chicken embryos and organs.

We have developed a wholemount immunofluorescence protocol for the simultaneous detection of up to three proteins in mouse and chicken embryos. Combined with Murray's clearing reagent (BABB) and microscope objectives with long working ranges and high numerical apertures mounted on a confocal microscope, cellular resolution can be obtained in depths offering the possibility of examining expression patterns in entire organs or embryos. Three-dimensional projections of the optical confocal sections can be computed with computer software allowing rotation around any axis.

Association between neuromedin U gene variants and overweight and obesity.

Background: Neuromedin U (NMU) is an anorexic neuropeptide expressed in the hypothalamus. Mice lacking the NmU gene are hyperphagic and obese, whereas mice overexpressing Nmu are hypophagic and lean.

Objective: Our objective was to investigate whether variants in NMU are associated with human obesity.

Stem cells and diabetes treatment.

Diabetes mellitus types 1 and 2 are characterized by absolute versus relative lack of insulin-producing beta cells, respectively. Reconstitution of a functional beta-cell mass by cell therapy--using organ donor islets of Langerhans--has been demonstrated to restore euglycaemia in the absence of insulin treatment. This remarkable achievement has stimulated the search for appropriate stem cell sources from which adequate expansion and maturation of therapeutic beta cells can be achieved.