Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

At present, only islet cell lines of animal origin have been successfully generated (e.g. RIN, HIT). A fully differentiated human beta cell line would be advantageous for diabetes research. We now report the generation of a human endocrine pancreatic cell line obtained by transfection using a plasmid containing the early region of SV40 viral DNA. Viral integration and transcription was assessed by Southern and Northern blotting. This cell line has been growing continuously for more than 2 years and maintains several of the characteristics of the parental cells from which they were generated. The presence of Neuron Specific Enolase, Protein Gene Product 9.5, cytokeratin, microvilli, cytoplasmic electrodense granules and the secretion of insulin, glucagon and somatostatin supports the neuroendocrine origin of this cell line. However, hormone production progressively decreased and finally stopped at passage 8. Flow cytometric analysis showed that HLA expression in this cell line is readily induced by IFN-gamma and modulated by TNF-alpha. The establishment of this human endocrine cell line indicates the feasibility of immortalizing human islets by transfection with viral oncogenes. To obtain a fully differentiated cell line it may be necessary to use other DNA constructs which immortalize the cells without fully transforming their phenotype.
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PMID:Transfection with SV40 gene of human pancreatic endocrine cells. 168 Mar 32

We examined the chronic (72 h) effects of 30 ng/ml recombinant murine tumor necrosis factor (TNF)-alpha on release of immunoreactive growth hormone (GH), prolactin (PRL), thyrotropin (TSH), and TSH glycosylation, as assessed by lectin binding, in cultured rat anterior pituitary cells. In cultured cells from adult female rats, TNF-alpha significantly suppressed basal and GH-releasing hormone (GRH)-stimulated GH release. TNF-alpha also suppressed basal PRL release and completely abolished the PRL response to TRH (0.1-10 nM). Whereas TNF-alpha reduced basal TSH release, it significantly enhanced the maximal TSH response to TRH. TNF-alpha did not affect the concanavalin A and lentil lectin binding of TSH accumulated in the medium during the 4-day culture, but significantly decreased the lentil lectin binding of TSH released in response to acute TRH stimulation. TNF-alpha significantly enhanced the inhibitory effect of somatostatin on stimulated PRL release, but not on GH or TSH release. Compared to cell cultures from adult female rats, in anterior pituitary cell cultures from 12-day-old rats the effects of prolonged exposure to TNF-alpha on hormone release were diminished or absent. Pituitary hormone release was unaffected by acute (3 h) exposure to TNF-alpha. These results demonstrate a direct effect of TNF-alpha on anterior pituitary hormone release, which is cell-type specific and age dependent.
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PMID:Prolonged effects of tumor necrosis factor-alpha on anterior pituitary hormone release. 747 97

Somatostatin (Sms) and its agonist analogues inhibit the secretory activities of endocrine and neural cells. Recent studies have suggested that Sms has significant immunomodulatory properties. In this study, we examine the effects of two Sms octapeptide analogues on the inflammatory reaction in vivo. BIM 23014 (Somatulin) and Sandostatin were administered to male Sprague-Dawley rats subject to carrageenin-induced aseptic inflammation, at doses of 2-10 micrograms/rat, given either systemically or locally. Animals were killed 7 h after the induction of the inflammation, and the inflammatory exudates were aspirated and quantitated in terms of volume and leukocyte concentration. Sms analogues, administered via either route, significantly reduced the volume and the leukocyte concentration of the exudate in a time- and dose-dependent fashion. In corroboration of these, immunohistochemical evaluation of the levels of local inflammatory mediators, such as immunoreactive (Ir) TNF-alpha, Irsubstance P, and Ircorticotropin-releasing hormone, was inhibited significantly by Sms analogue treatment. These findings suggest that Sms analogues have significant antiinflammatory effects in vivo, associated with suppression of proinflammatory cytokines and neuropeptides. Furthermore, these data suggest that Sms agonists may be useful in the control of inflammatory reaction.
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PMID:Somatostatin analogues suppress the inflammatory reaction in vivo. 751 91

Current evidence indicates that the neuroendocrine system is the highest regulator of immune/inflammatory reactions. Prolactin and growth hormone stimulate the production of leukocytes, including lymphocytes, and maintain immunocompetence. The hypothalamus-pituitary-adrenal axis constitutes the most powerful circuit regulating the immune system. The neuropeptides constituting this axis, namely corticotrophin releasing factor, adrenocorticotrophic hormone, alpha-melanocyte stimulating hormone, and beta-endorphin are powerful immunoregulators, which have a direct regulatory effect on lymphoid cells, regulating immune reactions by the stimulation of immunoregulatory hormones (glucocorticoids) and also by acting on the central nervous system which in turn generates immunoregulatory nerve impulses. Peptidergic nerves are major regulators of the inflammatory response. Substance P and calcitonin gene-related peptide are pro-inflammatory mediators and somatostatin is anti-inflammatory. The neuroendocrine regulation of the inflammatory response is of major significance from the point of view of immune homeostasis. Malfunction of this circuit leads to disease and often is life-threatening. The immune system emits signals towards the neuroendocrine system by cytokine mediators which reach significant blood levels (cytokine-hormones) during systemic immune/inflammatory reactions. Interleukin-1, -6, and TNF-alpha are the major cytokine hormones mediating the acute phase response. These cytokines induce profound neuroendocrine and metabolic changes by interacting with the central nervous system and with many other organs and tissues in the body. Corticotrophin releasing factor functions under these conditions as a major co-ordinator of the response and is responsible for activating the ACTH-adrenal axis for regulating fever and for other CNS effects leading to a sympathetic outflow. Increased ACTH secretion leads to glucocorticoid production. alpha-melanocyte stimulating hormone functions under these conditions as a cytokine antagonist and an anti-pyretic hormone. The sympathetic outflow, in conjunction with increased adrenal activity. leads to the elevation of catecholamines in the bloodstream and in tissues. Current evidence suggests that neuroimmune mechanisms are essential in normal physiology, such as tissue turnover, involution, atrophy, intestinal function, and reproduction. Host defence against infection, trauma and shock relies heavily on the neuroimmunoregulatory network. Moreover, abnormalities of neuroimmunoregulation contribute to the aetiology of autoimmune disease, chronic inflammatory disease, immunodeficiency, allergy, and asthma. Finally, neuroimmune mechanisms play an important role in regeneration and healing.
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PMID:The immune effects of neuropeptides. 891 48

The immunosuppressor effects of the widely distributed neuropeptide somatostatin were examined on purified peripheral blood human monocytes. Somatostatin, at concentrations thought to be physiologic (10(-10)-10(-7) M), regulated monocyte/macrophage responses to (LPS) stimulation, as reflected by interleukin production. In particular, somatostatin had direct inhibitory effects on TNF-alpha, IL-1 beta, and IL-6 secretion by LPS-activated monocytes, while the decrease on IL-8 synthesis was modulated mainly by the action of somatostatin on TNF-alpha and IL-1 beta. In fact, the addition of these two inflammatory cytokines to the monocyte culture medium was able to induce IL-8 expression, as demonstrated by mRNA analysis, also in presence of the neuropeptide. Although somatostatin affected IL-8 production in an indirect way, it suppressed directly the chemotactic response of neutrophils to IL-8. Finally, somatostatin downregulation of monocyte activation was confirmed by the decrease of HLA-DR expression on cell plasma membranes (52% versus 33%). Our results confirm that somatostatin exerts preferential effects on the suppression of immunoreactions by modulating cytokine production and activity.
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PMID:Modulation of cytokine production in activated human monocytes by somatostatin. 892 6

We investigated the effects of different neuropeptides on human dendritic cells (DC) maturation. Immature DC, derived from monocytes cultured for 6 days with IL-4 plus GM-CSF, have been exposed to somatostatin, substance P, or vasoactive intestinal peptide (VIP). Among these neuropeptides, only VIP induces the production of bioactive IL-12 and the neoexpression of CD83 on a fraction of the DC population, with an effect significant at 100 and 10 nM, respectively. These effects of VIP are dose-dependent, unaffected by polymixin B, and partly prevented by a VIP receptor antagonist. Although the effects of VIP alone remain modest, it synergizes with TNF-alpha to induce DC maturation. In the presence of a suboptimal concentration of TNF-alpha, which has no detectable effect on DC by itself, VIP induces the production of high levels of bioactive IL-12, the neoexpression of CD83 on almost all the DC population (with an effect significant at 10 and 0.1 nM, respectively), and the up-regulation of various adhesion and costimulatory molecule expression. Moreover, DC exposed to VIP plus a suboptimal concentration of TNF-alpha are as potent as mature DC obtained by treatment with an optimal concentration of TNF-alpha in stimulating allogenic T cell proliferation. Our data suggest that, in inflammatory sites, VIP may cooperate with proinflammatory mediators, such as TNF-alpha, to induce DC maturation.
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PMID:Vasoactive intestinal peptide synergizes with TNF-alpha in inducing human dendritic cell maturation. 1047 71

Intestinal epithelial cells secrete proinflammatory cytokines and chemokines that are crucial in mucosal defense. However, this secretion must be tightly regulated, because uncontrolled secretion of proinflammatory mediators may lead to chronic inflammation and mucosal damage. The aim of this study was to determine whether somatostatin, secreted within the intestinal mucosa, regulates secretion of cytokines from intestinal epithelial cells. The spontaneous as well as TNF-alpha- and Salmonella-induced secretion of IL-8 and IL-1beta derived from intestinal cell lines Caco-2 and HT-29 was measured after treatment with somatostatin or its synthetic analogue, octreotide. Somatostatin, at physiological nanomolar concentrations, markedly inhibited the spontaneous and TNF-alpha-induced secretion of IL-8 and IL-1beta. This inhibition was dose dependent, reaching >90% blockage at 3 nM. Furthermore, somatostatin completely abrogated the increased secretion of IL-8 and IL-1beta after invasion by Salmonella. Octreotide, which mainly stimulates somatostatin receptor subtypes 2 and 5, affected the secretion of IL-8 and IL-1beta similarly, and the somatostatin antagonist cyclo-somatostatin completely blocked the somatostatin- and octreotide-induced inhibitory effects. This inhibition was correlated to a reduction of the mRNA concentrations of IL-8 and IL-1beta. No effect was noted regarding cell viability. These results indicate that somatostatin, by directly interacting with its specific receptors that are expressed on intestinal epithelial cells, down-regulates proinflammatory mediator secretion by a mechanism involving the regulation of transcription. These findings suggest that somatostatin plays an active role in regulating the mucosal inflammatory response of intestinal epithelial cells after physiological and pathophysiological stimulations such as bacterial invasion.
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PMID:Somatostatin through its specific receptor inhibits spontaneous and TNF-alpha- and bacteria-induced IL-8 and IL-1 beta secretion from intestinal epithelial cells. 1097 2

Throughout the body, immune cells of various types, both classical (such as T-cells) and less recognized (such as intestinal epithelial cells) are exposed to a variety of neurotransmitters secreted from local nerve fibers. Moreover, immune cells express specific neurotransmitter receptors. Based on the above we asked whether neurotransmitters. by direct interaction with their receptors, can either evoke or block immune functions in general, and cytokine secretion in particular. We found that several neuropeptides (SOM, Sub P, CGRP and NPY), in nM concentration and in the absence of any additional stimulatory molecules, induced a significant secretion of cytokines from Th0, Th1 and Th2 antigen specific T-cells. Moreover, some neuropeptides surprisingly drove committed Thl and Th2 populations to a 'forbidden' cytokine secretion: secretion of Th2 cytokines from Th1 cells, and vice versa. We further found that SOM by itself markedly affected the secretion of proinflammatory cytokines from intestinal epithelial cells, which play a major role in the gut immunity in the mucosal defense against invading microorganisms. Thus, somatostatin, through its specific receptor, inhibits (> 90%) of the spontaneous, TNF-alpha or bacteria (Salmonella)-induced secretion of IL-8 and IL-1beta from two intestinal epithelial cell lines. Taken together, these observations suggest that neuropeptides can by themselves induce both typical and atypical cytokine secretion from T-cells and intestinal epithelial cells. Since a myriad of immune reactivities are mediated by, and dependent on, specific cytokines secreted from immune cells, the neuropeptide-induced effects may have important implications for numerous physiological and pathological conditions, including autoimmune diseases, chronic inflammation and neoplasias.
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PMID:Nerve-driven immunity: neuropeptides regulate cytokine secretion of T cells and intestinal epithelial cells in a direct, powerful and contextual manner. 1176 46

Pancreatic periacinar myofibroblasts are considered to be therapeutic targets for the suppression of acute pancreatitis. To elucidate the mechanisms mediating the therapeutic actions of somatostatin on acute pancreatitis, we investigated how somatostatin affects the tumor necrosis factor (TNF)-alpha-induced interleukin (IL)-6 and IL-8 secretion from pancreatic myofibroblasts. Cytokine secretion was determined by enzyme-linked immunosorbent assay (ELISA) and Northern blotting. Nuclear factor (NF)-kappaB DNA-binding activity was evaluated by electrophoretic mobility shift assay (EMSAs). The expression of somatostatin receptor (SSTR) mRNA was evaluated by reverse transcription-polymerase chain reaction (RT-PCR). Somatostatin dose-dependently inhibited the TNF-alpha-induced IL-6 secretion. In comparison, the effects on IL-8 secretion were modest. Northern blot analysis demonstrated that somatostatin decreased the TNF-alpha-induced IL-6 mRNA expression, and that this effect was completely blocked by the somatostatin antagonist cyclo-somatostatin. Furthermore, somatostatin suppressed TNF-alpha-induced NF-kappaB activation. These cells bear SSTR subtypes 1 and 2. Somatostatin down-regulated the TNF-alpha-induced IL-6 secretion in human pancreatic periacinar myofibroblasts. These findings suggest that some of the therapeutic actions of somatostatin on acute pancreatitis might be mediated by reducing local IL-6 secretion in the pancreas.
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PMID:Inhibitory effects of somatostatin on tumor necrosis factor-alpha-induced interleukin-6 secretion in human pancreatic periacinar myofibroblasts. 1206 Aug 57

Islet amyloid polypeptide (IAPP or amylin) is co-secreted with insulin from the pancreatic beta-cells. Transcription of the IAPP gene is controlled by a complex promoter region, spanning from -2798 to +450 relative to the transcriptional start site. In the present study, we have used reporter gene analysis and semi-quantitative RT-PCR to establish that insulin, glucagon, glucagon-like peptide-1 (GLP-1) and the GLP-1 derivatives GLP(7-36)Amide and Exendin-4 all stimulate IAPP promoter activity, as well as endogenous IAPP mRNA levels in isolated islets of Langerhans. In contrast, somatostatin had no effect, and whilst the inflammatory cytokines TNF-alpha, IL-1alpha and IL-1beta had no effect on promoter activity, they all decreased IAPP mRNA levels in isolated islets. Finally, utilising a series of deletion reporter gene constructs of the human IAPP gene promoter, we used overexpression studies to establish that HNF-3beta (FoxA2) negatively regulates the IAPP promoter, whilst the MODY3 transcription factor HNF-1alpha positively regulates promoter activity.
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PMID:Transcriptional regulation of the IAPP gene in pancreatic beta-cells. 1556 41


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