Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P61278 (somatostatin)
22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Well-orchestrated transcriptional regulation of pancreatic beta cells is essential for insulin production and glucose homeostasis. Pancreas duodenum homeobox-1 (PDX-1) is a key regulator of glucose-dependent insulin production and glucose metabolism. We find that PDX-1 interacts with the PDZ-domain coactivator Bridge-1 in yeast interaction trap assays. Rat Bridge-1 and PDX-1 interact directly in GST pull-down assays via Bridge-1 interactions with the amino-terminal transactivation domain of PDX-1. Bridge-1 also interacts with wild-type and mutant human PDX-1 (IPF-1) proteins and strongly interacts with the amino-terminal PDX-1 P63fsdelC (MODY4) mutant protein. Transcriptional activation by PDX-1 is increased by addition of Bridge-1 in multiple contexts, including synergistic activation of a Gal4 reporter by Gal4-Bridge-1 and Gal4-PDX-1 fusion proteins, activation of the somatostatin promoter TAAT1 enhancer, and synergistic activation of the rat insulin I promoter FarFlat enhancer by PDX-1, E12, and E47. We propose that the coactivator Bridge-1 modulates PDX-1 functions in the regulation of its target genes.
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PMID:The coactivator Bridge-1 increases transcriptional activation by pancreas duodenum homeobox-1 (PDX-1). 1588 79

Pancreas development relies on a network of transcription factors belonging mainly to the Homeodomain and basic Helix-Loop-Helix families. We show in this study that, in zebrafish, sox4, a member of the SRY-like HMG-box (SOX) family, is required for proper endocrine cell differentiation. We found that two genes orthologous to mammalian Sox4 are present in zebrafish and that only one of them, sox4b, is strongly expressed in the pancreatic anlage. Transcripts of sox4b were detected in mid-trunk endoderm from the 5-somite stage, well before the onset of expression of the early pancreatic gene pdx-1. Furthermore, by fluorescent double in situ hybridization, we found that expression of sox4b is mostly restricted to precursors of the endocrine compartment. This expression is not maintained in differentiated cells although transient expression can be detected in alpha cells and some beta cells. That sox4b-expressing cells belong to the endocrine lineage is further illustrated by their absence from the pancreata of slow-muscle-omitted mutant embryos, which specifically lack all early endocrine markers while retaining expression of exocrine markers. The involvement of sox4b in cell differentiation is suggested firstly by its up-regulation in mind bomb mutant embryos displaying accelerated pancreatic cell differentiation. In addition, sox4b knock-down leads to a drastic reduction in glucagon expression, while other pancreatic markers including insulin, somatostatin, and trypsin are not significantly affected. This disruption of alpha cell differentiation is due to down-regulation of the homeobox arx gene specifically in the pancreas. Taken together, these data demonstrate that, in zebrafish, sox4b is expressed transiently during endocrine cell differentiation and plays a crucial role in the generation of alpha endocrine cells.
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PMID:sox4b is a key player of pancreatic alpha cell differentiation in zebrafish. 1605 12

The ATP-sensitive K(+) channel (K(ATP) channel) in pancreatic beta-cells is a critical regulator in insulin secretion. We previously reported that transgenic mice expressing a dominant-negative form (Kir6.2G132S) of Kir6.2, a subunit of the K(ATP) channel, specifically in beta-cells develop severe hyperglycemia in adults (8 weeks of age). In this study, we conducted a long-term investigation of the phenotype of these transgenic mice. Surprisingly, hyperglycemia was spontaneously improved with concomitant improvement of pancreatic insulin content in the transgenic mice at >25 weeks of age. Insulin-positive cells and pancreatic duodenal homeobox 1 (PDX1)-positive cells both were clearly increased in the older compared with the younger transgenic mice. Interestingly, cells labeled with the lectin Dolichos biflorus agglutinin (DBA), a potential indicator of uncommitted pancreatic epithelial/ductal cells, were detected in the islets of the transgenic mice but not in those of wild-type mice. In addition, a subset of the DBA-labeled cells was positive for PDX1, insulin, glucagon, somatostatin, or pancreatic polypeptide. Moreover, some of the DBA-labeled cells were also positive for a proliferating cell marker. These results show that the Kir6.2G132S transgenic mouse is a useful model for studying beta-cell regeneration and that DBA-labeled cells participate in the process.
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PMID:Spontaneous recovery from hyperglycemia by regeneration of pancreatic beta-cells in Kir6.2G132S transgenic mice. 1680 60

Type 1 diabetes is caused by the destruction of pancreatic beta-cells by T cells of the immune system. Islet transplantation is a promising therapy for diabetes mellitus. Bone marrow stem cells (BMSC) have the capacity to differentiate into various cell lineages including endocrine cells of the pancreas. To investigate the conditions that allow BMSC to differentiate into insulin-producing cells, a novel in vitro method was developed by using the histone deacetylase inhibitor, trichostatin A (TSA). BMSC, cultured in presence of TSA, differentiated into islet-like clusters under appropriate culture conditions. These islet-like clusters were similar to the cells of the islets of the pancreas. The islet-like clusters showed endocrine gene expression typical for pancreatic beta-cell development and function, such as insulin (I and II), glucagon, somatostatin, GLUT-2, pancreatic duodenal homeobox-1 (PDX-1), and Pax 4. Immunocytochemistry confirmed islet-like clusters contained pancreatic hormones. The colocalization of insulin and C-peptide was also observed. Enzyme-linked immunosorbent assay analysis demonstrated that insulin secretion was regulated by glucose. Western blot analysis demonstrated the presence of stored insulin. Electron microscopy of the islet-like cells revealed an ultrastructure similar to that of pancreatic beta-cells, which contain insulin granules within secretory vesicles. These findings suggest that histone-deacetylating agents could allow the differentiation of BMSC into insulin-producing beta-cells.
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PMID:Chromatin-remodeling factors allow differentiation of bone marrow cells into insulin-producing cells. 1699 May 88

Distinct subtypes of cortical GABAergic interneurons provide inhibitory signals that are indispensable for neural network function. The Dlx homeobox genes have a central role in regulating their development and function. We have characterized the activity of three cis-regulatory sequences involved in forebrain expression of vertebrate Dlx genes: upstream regulatory element 2 (URE2), I12b, and I56i. The three regulatory elements display regional and temporal differences in their activities within the lateral ganglionic eminence (LGE), medial ganglionic eminence (MGE), and caudal ganglionic eminence (CGE) and label distinct populations of tangentially migrating neurons at embryonic day 12.5 (E12.5) and E13.5. We provide evidence that the dorsomedial and ventral MGE are distinct sources of tangentially migrating neurons during midgestation. In the adult cortex, URE2 and I12b/I56i are differentially expressed in parvalbumin-, calretinin-, neuropeptide Y-, and neuronal nitric oxide synthase-positive interneurons; I12b and I56i were specifically active in somatostatin-, vasoactive intestinal peptide-, and calbindin-positive interneurons. These data suggest that interneuron subtypes use distinct combinations of Dlx1/Dlx2 enhancers from the time they are specified through adulthood.
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PMID:Distinct cis-regulatory elements from the Dlx1/Dlx2 locus mark different progenitor cell populations in the ganglionic eminences and different subtypes of adult cortical interneurons. 1749 87

Cortical pyramidal cells are generated from pallial neuroepithelial precursors, whereas GABAergic interneurons originate in subpallial germinal zones and migrate tangentially to reach the cortex. Using Cre-lox technology in transgenic mice and a series of molecular markers that subdivide the subpallial neuroepithelium into small domains, we fate-map precursor pools and identify interneurons generated from each domain. Cortical interneurons expressing calbindin, parvalbumin, and somatostatin are generated exclusively from Lhx6 (Lim homeobox 6)-expressing precursors in the medial ganglionic eminence (MGE). Martinotti cells that coexpress calretinin and somatostatin are generated from the dorsal region of the MGE neuroepithelium that expresses Nkx6.2 (NK2 transcription factor-related 6.2). Most neuropeptide Y-expressing cells and all bipolar calretinin-expressing interneurons are generated outside the MGE, from the germinal zones of the lateral/caudal ganglionic eminences that express Gsh2 (genomic screened homeobox 2). Our data demonstrate that subpallial neuroepithelial domains defined by expression of genetic determinants generate distinct interneuron subtypes, thereby contributing to the generation of cortical interneuron heterogeneity observed in the adult cortex.
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PMID:Spatial genetic patterning of the embryonic neuroepithelium generates GABAergic interneuron diversity in the adult cortex. 1792 35

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

The En2 gene, coding for the homeobox-containing transcription factor Engrailed-2 (EN2), has been associated to autism spectrum disorder (ASD). Due to neuroanatomical and behavioral abnormalities, which partly resemble those observed in ASD patients, En2 knockout (En2(-/-)) mice have been proposed as a model for ASD. In the mouse embryo, En2 is involved in the specification of midbrain/hindbrain regions, being predominantly expressed in the developing cerebellum and ventral midbrain, and its expression is maintained in these structures until adulthood. Here we show that in the adult mouse brain, En2 mRNA is expressed also in the hippocampus and cerebral cortex. Hippocampal En2 mRNA content decreased after seizures induced by kainic acid (KA). This suggests that En2 might also influence the functioning of forebrain areas during adulthood and in response to seizures. Indeed, a reduced expression of parvalbumin and somatostatin was detected in the hippocampus of En2(-/-) mice as compared to wild-type (WT) mice, indicating an altered GABAergic innervation of limbic circuits in En2(-/-) mice. In keeping with these results, En2(-/-) mice displayed an increased susceptibility to KA-induced seizures. KA (20 mg/kg) determined more severe and prolonged generalized seizures in En2(-/-) mice, when compared to WT animals. Seizures were accompanied by a widespread c-fos and c-jun mRNA induction in the brain of En2(-/-) but not WT mice. Long-term histopathological changes (CA1 cell loss, upregulation of neuropeptide Y) also occurred in the hippocampus of KA-treated En2(-/-) but not WT mice. These findings suggest that En2(-/-) mice might be used as a novel tool to study the link between epilepsy and ASD.
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PMID:Increased susceptibility to kainic acid-induced seizures in Engrailed-2 knockout mice. 1918 8

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

Dlx5 and Dlx6 homeobox genes are expressed in developing and mature cortical interneurons. Simultaneous deletion of Dlx5 and 6 results in exencephaly of the anterior brain; despite this defect, prenatal basal ganglia differentiation appeared largely intact, while tangential migration of Lhx6(+) and Mafb(+) interneurons to the cortex was reduced and disordered. The migration deficits were associated with reduced CXCR4 expression. Transplantation of mutant immature interneurons into a wild-type brain demonstrated that loss of either Dlx5 or Dlx5&6 preferentially reduced the number of mature parvalbumin(+) interneurons; those parvalbumin(+) interneurons that were present had increased dendritic branching. Dlx5/6(+/-) mice, which appear normal histologically, show spontaneous electrographic seizures and reduced power of gamma oscillations. Thus, Dlx5&6 appeared to be required for development and function of somal innervating (parvalbumin(+)) neocortical interneurons. This contrasts with Dlx1, whose function is required for dendrite innervating (calretinin(+), somatostatin(+), and neuropeptide Y(+)) interneurons (Cobos et al., 2005).
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PMID:Dlx5 and Dlx6 regulate the development of parvalbumin-expressing cortical interneurons. 2039 55


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