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)

During fetal development, paired/homeodomain transcription factor Pax4 controls the formation of the insulin-producing beta cells and the somatostatin-producing delta cells in the islets of Langerhans in the pancreas. Targeting of Pax4 expression to the islet lineage in the fetal pancreas depends on a short sequence located approximately 2 kb upstream of the transcription initiation site of the PAX4 gene. This short sequence contains binding sites for homeodomain transcription factors PDX1 and hepatic nuclear factor (HNF)1, nuclear receptor HNF4alpha, and basic helix-loop-helix factor Neurogenin3. In the current study we demonstrate that the HNF1alpha and Neurogenin3 binding sites are critical for activity of the region through synergy between the two proteins. Synergy involves a physical interaction between the factors and requires the activation domains of both factors. Furthermore, exogenous expression of Neurogenin3 is sufficient to induce expression of the endogenous pax4 gene in the mouse pancreatic ductal cell line mPAC, which already expresses HNF1alpha, whereas expression of both Neurogenin3 and HNF1alpha are necessary to activate the pax4 gene in the fibroblast cell line NIH3T3. These data demonstrate how Neurogenin3 and HNF1alpha activate the pax4 gene during the cascade of gene expression events that control pancreatic endocrine cell development.
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PMID:Neurogenin3 and hepatic nuclear factor 1 cooperate in activating pancreatic expression of Pax4. 1283 60

The COUP-TFII nuclear receptor, also known as NR2F2, is expressed in the developing ventral telencephalon and modulates the tangential migration of a set of subpallial neuronal progenitors during forebrain development. Little information is available about its expression patterns in the adult brain. We have identified the cell populations expressing COUP-TFII and the contribution of some of them to network activity in vivo. Expression of COUP-TFII by hippocampal pyramidal and dentate granule cells, as well as neurons in the neocortex, formed a gradient increasing from undetectable in the dorsal to very strong in the ventral sectors. In the dorsal hippocampal CA1 area, COUP-TFII was restricted to GABAergic interneurons and expressed in several, largely nonoverlapping neuronal populations. Immunoreactivity was present in calretinin-, neuronal nitric oxide synthase-, and reelin-expressing cells, as well as in subsets of cholecystokinin- or calbindin-expressing or radiatum-retrohippocampally projecting GABAergic cells, but not in parvalbumin- and/or somatostatin-expressing interneurons. In vivo recording and juxtacellular labeling of COUP-TFII-expressing cells revealed neurogliaform cells, basket cells in stratum radiatum and tachykinin-expressing radiatum dentate innervating interneurons, identified by their axodendritic distributions. They showed cell type-selective phase-locked firing to the theta rhythm but no activation during sharp wave/ripple oscillations. These basket cells in stratum radiatum and neurogliaform cells fired at the peak of theta oscillations detected extracellularly in stratum pyramidale, unlike previously reported ivy cells, which fired at the trough. The characterization of COUP-TFII-expressing neurons suggests that this developmentally important transcription factor plays cell type-specific role(s) in the adult hippocampus.
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PMID:Expression of COUP-TFII nuclear receptor in restricted GABAergic neuronal populations in the adult rat hippocampus. 2013 Jan 70

In the present work, we have evaluated the possibility of preventing liver carcinogenesis in rats at two stages of development. In the first series of experiments, we induced foci of altered hepatocytes, (FAH) which represent the first events in rodent liver carcinogenesis, using the chemical mutagens diethylnitrosamine (DEN) and acetylaminofluorene (AAF). In the second part of the work, we used repeated weekly injections of DEN only that gave rise to significant fibrosis at 11 weeks and the development of malignant tumours at 16 weeks. We chose to assess the chemopreventive effect of three different drugs: pioglitazone, lanreotide and S-trans-trans-farnesylthiosalicylic acid (FTS). Pioglitazone (PGZ) is an agonist of peroxisome proliferator-activated receptor gamma (PPARg), itself a member of the nuclear receptor superfamily, responsible for the modulation of a number of metabolic pathways, including cell differentiation, metabolism of lipids and inflammation. Lanreotide (LAN) is a somatostatin analogue that has an inhibitory effect on the release of several hormones, such as growth hormone and serotonine. FTS is a specific antagonist of the protoocogene Ras, tested here based on the rationale that Ras is activated in many hepatocellular carcinomas (HCC). We showed that both PGZ and LAN were efficient in the first, pre-neoplastic model, by reducing the size of FAH, decreasing proliferation specifically in FAH by interacting with proteins of the cell cycle. We could also demonstrate that LAN increased apoptosis. In the second model, LAN was able to diminish the number of established HCC by decreasing proliferation, in parallel with an anti-fibrotic action. Furthermore, enhanced apoptosis and antiangiogenic effects were observed when LAN was given from the start of the carcinogenic induction by DEN. The cellular mechanisms leading to its effects warrant further investigations. FTS also strongly inhibited the appearance of FAH and HCC in the second model, through a complete inhibition of Ras activation and the induction of pro-apoptotic pathways. On the contrary, PGZ did not prevent the appearance of neoplastic lesions. For these reasons, we did not analyse further its mechanism of action in the second model. Altogether, the results we obtained demonstrate an activity of both LAN and FTS, at the early onset of liver carcinogenesis, and later on when advanced fibrosis, cirrhosis and HCC are induced. These anti-tumoural effects could be complementary and will be tested in combination in the future.
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PMID:Chemoprevention of hepatocellular carcinoma. Proof of concept in animal models. 2156 52