Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Islet-like cells derived from embryonic stem (ES) cells may be a promising therapeutic option for future diabetes treatment. Here, we demonstrated a five-stage protocol with adding exendin-4 instead of nicotinamide finally could generate islet-like cells from human embryonic stem (ES) cells. Immunofluorescence analysis revealed a high percentage of c-peptide positive cells in the derivation. However, in addition to insulin/c-peptide, most cells also coexpressed PDX-1 (pancreas duodenum homeobox-1), glucagon, somatostatin or pancreatic polypeptide. Insulin and other pancreatic beta-cell-specific genes were all present in the differentiated cells. Insulin secretion could be detected and increased significantly by adding KCL in high glucose concentration in vitro. Furthermore, subcutaneous transplantation of scaffolds seeded with the islet-like cells or cell transplantation under kidney capsules for further differentiation in vivo could improve 6h fasted blood glucose levels and diabetic phenotypes in streptozotocin-induced diabetic SCID mice. More interestingly, blood vessels of host origin, characterized by mouse CD31 immunostaining, invaded the cell-scaffold complexes. This work reveals a five-stage protocol with adding exendin-4 may be an effective protocol on the differentiation of human ES cells into islet-like cells, and suggests scaffolds can serve as vehicles for islet-like cell transplantation.
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PMID:The reversal of hyperglycaemia in diabetic mice using PLGA scaffolds seeded with islet-like cells derived from human embryonic stem cells. 1913 50

Pancreatic islets and acinar tissue develop from duct epithelium and share expression of several transcription factors and other molecular markers also involved with the development of neural tissues. We examined rat pancreatic tissue from fetal life until adulthood for the expression of N-myc downstream regulated gene 4 (Ndrg4), a gene shown to be expressed during neuronal cell differentiation. Isolated pancreatic ducts from neonatal rats were maintained in culture and gave rise to clusters of cells expressing nestin (NES) and PDX-1, which subsequently contained immunoreactive glucagon. Using reverse transcription PCR (RT-PCR), we identified mRNA expression and immunoreactive protein presence for NDRG4 in cultured duct-derived cells, and brain of neonatal rats. By PCR cloning of the ductal cell-derived DNA the molecular form of NDRG4 expressed in pancreatic ducts and ARIP rat pancreatic cells was identified as NDRG4A2, and its presence in intact pancreas of fetal and neonatal rats was demonstrated by immunohistochemistry. Incubation of ARIP cells with glucagon-like polypeptide-1 (GLP-1), increased the expression of NDRG4A2 and PDX-1, while decreasing DNA synthesis and promoting the appearance of glucagon-positive cells. This inhibitory effect of GLP-1 on DNA synthesis and the stimulatory effect on endocrine differentiation were reversed when the translation of NDRG4A2 was prevented using siRNA. These findings indicate that NDRG4A2 is expressed in pancreatic duct cells under GLP-1 control and may be related to a reduction in proliferation and the onset of the pancreas cell differentiation.
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PMID:Identification and action of N-myc downstream regulated gene 4 A2 in rat pancreas. 1919 16

To facilitate the immunological reaction of antibodies with antigens in fixed tissues, it is necessary to unmask or retrieve the antigens through pretreatment of the specimens. However, adjustment of heat-induced antigen retrieval is always required for different tissues and antigens. Using a low-power antigen retrieval technique, with appropriate dilution of antibodies, we successfully immunostained key antigens in the pancreas such as insulin, PDX-1, glucagon, cytokeratin, and CD31, which have presented a particular challenge for investigators in the past, because of the rapid autodigestion and high nonspecific antibody binding in the tissue. Satisfactory results were obtained when immunohistochemistry and fluorescence in situ hybridization analysis were combined in the same slides.
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PMID:Fluorescent immunohistochemistry and in situ hybridization analysis of pancreas. 1950 51

It was recently reported that pluripotent mesenchymal stem cells (MSCs) in rodent bone marrow (BM) have the capacity to generate insulin-producing cells (IPCs) in vitro. However, little is known about this capacity in human BM-MSCs. We developed a nongenetic method to induce human BM-MSCs to transdifferentiate into IPCs both phenotypically and functionally. BM-MSCs from 12 human donors were sequentially cultured in specially defined conditions. Their differentiation extent toward beta-cell phenotype was evaluated systemically. Specifically, after induction human BM-MSCs formed spheroid islet-like clusters containing IPCs, which was further confirmed by dithizone (DTZ) staining and electron microscopy. These IPCs expressed multiple genes related to the development or function of pancreatic beta cells (including NKX6.1, ISL-1, Beta2/Neurod, Glut2, Pax6, nestin, PDX-1, ngn3, insulin and glucagon). The coexpression of insulin and c-peptide was observed in IPCs by immunofluorescence. Moreover, they were able to release insulin in a glucose-dependent manner and ameliorate the diabetic conditions of streptozotocin (STZ)-treated nude mice. These results indicate that human BM-MSCs might be an available candidate to overcome limitations of islet transplantation.
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PMID:Human bone marrow mesenchymal stem cells differentiate into insulin-producing cells upon microenvironmental manipulation in vitro. 1950 29

beta1 integrin and collagen matrix interactions regulate the survival of cells by associating with focal adhesion kinase (FAK) and initiating MAPK/ERK signalling, but little is known about these signalling pathways during human fetal islet ontogeny. The purpose of this study was to investigate whether beta1 integrin/FAK activation of the MAPK/ERK pathway regulates human fetal islet cell expression of endocrine cell markers and survival. Isolated human (18-21 weeks fetal age) islet-epithelial cell clusters, cultured on collagen I, were examined using beta1 integrin blocking antibody, beta1 integrin siRNA and FAK expression vector. Perturbing beta1 integrin function in the human fetal islet-epithelial cell clusters resulted in a marked decrease in cell adhesion, in parallel with a reduction in the number of cells expressing PDX-1, insulin and glucagon (p < 0.05). beta1 integrin blockade disorganized focal adhesion contacts in the PDX-1(+) cells and decreased activation of FAK and ERK1/2 signalling in parallel with an increase in expression of cleaved caspases 9 and 3 (p < 0.01). Similar results were obtained following an siRNA knock-down of beta1 integrin expression. In contrast, over-expression of FAK not only increased phospho-ERK and the expression of PDX-1, insulin and glucagon (p < 0.05) but also abrogated the decreases in phospho-ERK and PDX-1 by beta1 integrin blockade. This study demonstrates that activation of the FAK/ERK signalling cascade by beta1 integrin is involved in the differentiation and survival of human fetal pancreatic islet cells.
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PMID:beta1 integrin/FAK/ERK signalling pathway is essential for human fetal islet cell differentiation and survival. 1954 55

The success of cell replacement therapy for diabetes depends on the availability and generation of an adequate number of islets, preferably from an autologous origin. Stem cells are now being probed for the generation of physiologically competent, insulin-producing cells. In this investigation, we explored the potential of adipose tissue-derived stem cells (ASCs) to differentiate into pancreatic hormone-expressing islet-like cell aggregates (ICAs). We initiated ASC culture from epididymal fat pads of Swiss albino mice to obtain mesenchymal cells, murine epididymal (mE)-ASCs. Subsequent single-cell cloning resulted in a homogeneous cell population with a CD29(+)CD44(+)Sca-1(+) surface antigen expression profile. We formulated a 10-day differentiation protocol to generate insulin-expressing ICAs from mE-ASCs by progressively changing the differentiation cocktail on day 1, day 3, and day 5. Our stage-specific approach successfully differentiated mesodermic mE-ASCs into definitive endoderm (cells expressing Sox17, Foxa2, GATA-4, and cytokeratin [CK]-19), then into pancreatic endoderm (cells expressing pancreatic and duodenal homeobox [PDX]-1, Ngn3, NeuroD, Pax4, and glucose transporter 2), and finally into cells expressing pancreatic hormones (insulin, glucagon, somatostatin). Fluorescence-activated cell sorting analysis showed that day 5 ICAs contained 64.84% +/- 7.03% PDX-1(+) cells, and in day 10 mature ICAs, 48.17% +/- 3% of cells expressed C-peptide. Day 10 ICAs released C-peptide in a glucose-dependent manner, exhibiting in vitro functionality. Electron microscopy of day 10 ICAs revealed the presence of numerous secretory granules within the cell cytoplasm. Calcium alginate-encapsulated day 10 ICAs (1,000-1,200), when transplanted i.p. into streptozotocin-induced diabetic mice, restored normoglycemia within 2 weeks. The data presented here demonstrate the feasibility of using ASCs as a source of autologous stem cells to differentiate into the pancreatic lineage.
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PMID:Generation of pancreatic hormone-expressing islet-like cell aggregates from murine adipose tissue-derived stem cells. 1954 26

beta-Cell replacement therapy via islet transplantation is a promising possibility for the optimal treatment of type 1 diabetes. However, such an approach is severely limited by the shortage of donor organs. Pancreatic stem/progenitor cells could become a useful target for beta-cell replacement therapy in diabetic patients because the cells are abundantly available in the pancreas of these patients and in donor organs. In this study, we established a mouse pancreatic stem cell line without genetic manipulation. The duct-rich population after islet isolation was inoculated into 96-well plates in limiting dilution. From over 200 clones, 15 clones were able to be cultured for over 3 months. The HN#13 cells, which had the highest expression of insulin mRNA after induction, expressed PDX-1 transcription factor, glucagon-like peptide-1 (GLP-1) receptor, and cytokeratin-19 (duct-like cells). These cells continue to divide actively beyond the population doubling level (PDL) of 300. Exendin-4 treatment and transduction of PDX-1 and NeuroD proteins by protein transduction technology in HN#13 cells induced insulin and pancreas-related gene expression. This cell line could be useful for analyzing pancreatic stem cell differentiation. Moreover, the isolation technique might be useful for identification and isolation of human pancreatic stem/progenitor cells.
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PMID:Establishment of mouse pancreatic stem cell line. 1977 18

Endocannabinoid system is involved in food intake and energy balance. Beside the hypothalamus, pancreatic islet also expresses CB1 cannabinoid receptor, however little is known about its physiological role and regulation. Since gene expression of many specific proteins of the islet depends on the concentration of glucose, we studied CB1 receptor expression in response to fasting and feeding. Whole pancreas or islets were isolated from food-deprived adult Wistar rats, with or without a previous 1.5 g/kg glucose oral-intake. CB1, insulin and glucagon expressions were analyzed by confocal immunofluorescence and PCR. In vitro, rat islets were cultured at different glucose concentrations, in the presence of anandamide, or with Rimonabant analog BAR-1. CB1, insulin, glucagon, glucokinase, and PDX-1 expression were determined by real-time RT-PCR, and insulin secretion and islet content by ELISA. CB1 expression in pancreatic islets is upregulated during food restriction, and decreases in response to glucose intake or feeding. In cultured islets, 16 mmol/l glucose, BAR-1, and anandamide at low glucose reduced CB1 mRNA. Insulin, glucagon, glucokinase and PDX-1 expression increased in islets treated with anandamide at low glucose, while BAR-1 modified PDX-1 and glucagon mRNA at high glucose. Basal insulin secretion and insulin content in islets increased with anandamide, but not the glucose-stimulated response. Our results suggest that the endocannabinoid system has an important role in gene expression on islets and its close relationship with glucose response.
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PMID:CB1 cannabinoid receptor expression is regulated by glucose and feeding in rat pancreatic islets. 2045 64

Stem cells are critical in maintaining adult homeostasis and have been proposed to be the origin of many solid tumors, including pancreatic cancer. Here we demonstrate the expression patterns of the putative intestinal stem cell marker DCAMKL-1 in the pancreas of uninjured C57BL/6 mice compared with other pancreatic stem/progenitor cell markers. We then determined the viability of isolated pancreatic stem/progenitor cells in isotransplantation assays following DCAMKL-1 antibody-based cell sorting. Sorted cells were grown in suspension culture and injected into the flanks of athymic nude mice. Here we report that DCAMKL-1 is expressed in the main pancreatic duct epithelia and islets, but not within acinar cells. Coexpression was observed with somatostatin, NGN3, and nestin, but not glucagon or insulin. Isolated DCAMKL-1+ cells formed spheroids in suspension culture and induced nodule formation in isotransplantation assays. Analysis of nodules demonstrated markers of early pancreatic development (PDX-1), glandular epithelium (cytokeratin-14 and Ep-CAM), and isletlike structures (somatostatin and secretin). These data taken together suggest that DCAMKL-1 is a novel putative stem/progenitor marker, can be used to isolate normal pancreatic stem/progenitors, and potentially regenerates pancreatic tissues. This may represent a novel tool for regenerative medicine and a target for anti-stem cell-based therapeutics in pancreatic cancer.
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PMID:Identification of a novel putative pancreatic stem/progenitor cell marker DCAMKL-1 in normal mouse pancreas. 2053 4

Recent evidence has shown that stem cell factor (SCF) and its receptor, c-Kit, have an important role in pancreatic islet development by promoting islet cell differentiation and proliferation. In this study, we examined the role of c-Kit and SCF in the differentiation and proliferation of insulin- and glucagon-producing cells using a human pancreatic duct cell line (PANC-1). Our study showed that increased expression of endocrine cell markers (such as insulin and glucagon) and transcription factors (such as PDX-1 and PAX-6) coincided with a decrease in CK19(+) and c-Kit(+) cells (P<0.001) during PANC-1 cell differentiation, determined by immunofluorescence and qRT-PCR. Cells cultured with exogenous SCF showed an increase in insulin(+) (26%) and glucagon(+) (35%) cell differentiation (P<0.01), an increase in cell proliferation (P<0.05) and a decrease in cell apoptosis (P<0.01). siRNA knockdown of c-Kit resulted in a decrease in endocrine cell differentiation with a reduction in PDX-1 and insulin mRNA, as well as the number of cells immunostaining for PDX-1 and insulin. Taken together, these results show that c-Kit/SCF interactions are involved in mediating islet-like cluster formation and islet-like cell differentiation in a human pancreatic duct cell line.
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PMID:c-Kit and stem cell factor regulate PANC-1 cell differentiation into insulin- and glucagon-producing cells. 2053 Dec 94


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