131 research outputs found
Influence of long-range transported dust particles on local air quality: A case study on the Asian dust episodes in Taipei during the spring of 2002
No full textsj-xlsx-1-imr-10.1177_03000605221141312 - Supplemental material for CCK regulates osteogenic differentiation through TNFα/NF-κB in peri-implantitis
No full textSupplemental material, sj-xlsx-1-imr-10.1177_03000605221141312 for CCK regulates osteogenic differentiation through TNFα/NF-κB in peri-implantitis by LongHang Chou, YaTing Chang, KaiWen Lan, Meng Liu, YuKun Lu, XiaoLei Li, PeiRu Li and Yue Xu in Journal of International Medical Research</p
Novel Mechanism of Fatty Acid Sensing in Enteroendocrine Cells: Specific Structures in Oxo‐Fatty Acids Produced by Gut Bacteria Are Responsible for CCK Secretion in STC‐1 Cells via GPR40
Full text linkScope The secretion of gut hormones, such as cholecystokinin (CCK) is stimulated by fatty acids. Although a chain length?dependent mechanism has been proposed, other structural relationships to releasing activity remain unclear. We aimed to elucidate specific structures in fatty acids that are responsible for their CCK-releasing activity, and related sensing mechanisms in enteroendocrine cells. Methods and results CCK secretory activities were examined in a murine CCK-producing cell line STC-1 by exposing the cells to various modified fatty acids produced by gut lactic acid bacteria. The effects of fatty acids on gastric emptying rate as a CCK-mediated function were examined using acetaminophen and phenol red methods in rats. Out of more than 30 octadecanoic-derived fatty acids tested, 5 oxo-fatty acids potently stimulated CCK secretion without cytotoxic effects in STC-1 cells. Three fatty acids had a distinct specific structure containing one double bond, whereas the other two had two double bonds, nearby an oxo residue. CCK secretion induced by representative fatty acids (10-oxo-trans-11-18:1 and 13-oxo-cis-9,cis-15-18:2) was attenuated by a fatty acid receptor G-protein coupled receptor 40 antagonist. Oral administration of 13-oxo-cis-9,cis-15-18:2 lowered the gastric emptying rate in rats in a dose- and structure-dependent manner. Conclusion These results reveal a novel fatty acid-sensing mechanism in enteroendocrine cells
Cellular and subcellular localization of cholecystokinin (CCK)-1 receptors in the pancreas, gallbladder, and stomach of mice
Full text linkInformation concerning the cellular localization of cholecystokinin (CCK)-1 receptors has been discrepant and remained scanty at ultrastructural levels. The present immunohistochemical study at light and electron microscopic levels revealed the distinct localization of CCK1 receptors in visceral organs. Immunohistochemistry by use of a purified antibody against mouse CCK1 receptor was applied to fixed tissue sections of the pancreas, gallbladder, stomach, and intestine of mice. A silver-intensified immunogold method revealed the subcellular localization under electron microscope. The immunoreactivity for CCK1 receptors was selectively found in the basolateral membrane of pancreatic acinar cells and gastric chief cells but was absent in pancreatic islets and gastric D cells. Another intense expression in the gut was seen in the myenteric nerve plexus of the antro-duodenal region and some populations of c-Kit-expressing pacemaker cells in the duodenal musculature. The gallbladder contained smooth muscle fibers with an intense immunoreactivity of CCK1 receptors on cell surfaces. The restricted localization of CCK1 receptors on the basolateral membrane of pancreatic acinar cells and gastric chief cells, along with their absence in the islets of Langerhans and gastric D cells, provides definitive information concerning the regulatory mechanism by circulating CCK. Especially, the subcellular localization in the acinar cells completes the investigation for the detection of circulating CCK by the basolateral membrane
2-Arachidonoyl glycerol potently induces cholecystokinin secretion in murine enteroendocrine STC-1 cells via cannabinoid receptor CB1
Full text linkCholecystokinin (CCK) is a peptide hormone secreted from enteroendocrine cells and regulates the exocrine pancreas, gastric motility, and appetite. Dietary triacylglycerols are hydrolyzed to fatty acids (FA) and 2-monoacylglycerols (2-MAG) in the small intestine. Although it is well known that FA stimulate CCK secretion, whether 2-MAG have the CCK-releasing activity remains unclear. We examined the CCK-releasing activity of four commercially available 2-MAG in a murine CCK-producing cell line, STC-1, and the molecular mechanism underlying 2-MAG-induced CCK secretion. CCK released from the cells was measured using ELISA. Among four 2-MAG (2-palmitoyl, 2-oleoyl, 2-linoleoyl, and 2-arachidonoyl monoacylglycerols) examined, 2-arachidonoyl glycerol (2-AG) potently stimulated CCK secretion in a dose-dependent manner. Structurally related compounds, such as 2-arachidonoyl glycerol ether and 1-arachidonoyl glycerol, did not stimulate CCK secretion. Both arachidonic acid and 2-AG stimulated CCK secretion at 100 mu M, but only 2-AG did at 50 mu M. 2-AG-induced CCK secretion but not arachidonic acid-induced CCK secretion was attenuated by treatment with a cannabinoid receptor 1 (CB1) antagonist. These results indicate that a specific 2-MAG, 2-AG, directly stimulates CCK secretion via CB1
Cholecystokinin secretion induced by β-conglycinin peptone depends on Gαq-mediated pathways in enteroendocrine cells
Full text linkBackground Intraduodenal administration of peptone prepared from soybean β-conglycinin (BconP) stimulates cholecystokinin (CCK) secretion from enteroendocrine cells, and suppresses food intake in rats. However, the sensing mechanism of BconP by CCK-producing cells is unknown. Aim of the study We investigated signal transduction pathways mediating CCK secretion in response to BconP in the murine CCK-producing cell line, STC-1. Methods STC-1 cells were seeded in 48-well culture plates until sub-confluent and CCK secretion was examined under various conditions. CCK concentration was determined by the enzyme immunoassay. Results BconP dose-dependently induced CCK secretion in STC-1 cells. Treatment with BAPTA-AM, an intracellular Ca2+ chelator, reduced BconP-induced CCK secretion, however, removal of extracellular Ca2+ did not affect the secretory response. Treatment with 2-amino borate (2-APB) reduced CCK releasing responses, suggesting the involvement of IP3. In addition, BconP failed to induce CCK secretion after treatment with the Gαq protein inhibitor (YM-254890). Conclusion These results indicate that Gαq pathway is responsible for BconP-induced CCK secretion in STC-1 cells, and suggest the involvement of a Gαq-coupled GPCR(s) in dietary peptide sensing in enteroendocrine cells
Zinc directly stimulates cholecystokinin secretion from enteroendocrine cells and reduces gastric emptying in rats
Full text linkZinc, an essential mineral element, regulates various physiological functions such as immune responses and hormone secretion. Cholecystokinin (CCK), a gut hormone, has a role in protective immunity through the regulation of gastrointestinal motility, appetite, and inflammatory response. Here, we examined the effect of zinc on CCK secretion in STC-1 cells, an enteroendocrine cell line derived from murine duodenum, and in rats. Extracellular zinc triggered CCK secretion accompanied with increased intracellular Ca2+ and Zn2+ mobilization in STC-1 cells. Zinc-induced CCK secretion was abolished in the absence of intracellular Zn2+ or extracellular calcium. Upon inhibition of transient receptor potential ankyrin 1 (TRPA1), extracellular zinc failed to increase intracellular Ca2+ and subsequent CCK secretion. In rats, oral zinc administration decreased gastric emptying through the activation of CCK signaling. These results suggest that zinc is a novel stimulant for CCK secretion through the activation of TRPA1 related to intracellular Zn2+ and Ca2+ mobilization
Calcium-sensing receptor mediates phenylalanine-induced cholecystokinin secretion in enteroendocrine STC-1 cells
Full text linkIntraluminal l-phenylalanine (Phe) stimulates cholecystokinin (CCK) secretion in vivo and in vitro. However, the cellular mechanism by which CCK-producing enteroendocrine cells sense Phe is unknown. The calcium-sensing receptor (CaR) can sense amino acids, and is expressed in the gastrointestinal tract. In the present study, we examined whether CaR functions as a receptor for Phe in CCK-producing enteroendocrine cells. CCK secretion and intracellular Ca2+ concentration in response to Phe were measured in the murine CCK-producing enteroendocrine cell line STC-1 at various extracellular Ca2+ concentrations or after treatment with a CaR antagonist. At more than 20 mm, Phe induced dose-dependent CCK secretion and intracellular Ca2+ mobilization in STC-1 cells. In the presence of 3.0 mm extracellular Ca2+, 10 and 20 mm Phe induced significantly higher CCK secretion than under normal conditions (1.2 mm extracellular Ca2+). Intracellular Ca2+ mobilization, induced by 10 or 20 mm Phe, was also enhanced by increasing extracellular Ca2+ concentrations. In addition, intracellular Ca2+ mobilization induced by addition of extracellular Ca2+ was augmented by the presence of Phe. These results closely match the known CaR properties. Treatment with a specific CaR antagonist (NPS2143) completely inhibited Phe-induced CCK secretion and the latter phase of intracellular Ca2+ mobilization. CaR mRNA expression was demonstrated by RT-PCR in STC-1 cells, as well as in other mouse tissues including the kidney, thyroid, stomach and intestine. In conclusion, CaR functions as a receptor for Phe, stimulating CCK secretion in enteroendocrine STC-1 cells
Additional file 1: of Augmented antitumor activity by olaparib plus AZD1775 in gastric cancer through disrupting DNA damage repair pathways and DNA damage checkpoint
No full textFigure S1. Synergistic growth-inhibition between AZD1775 and olaparib in GC cells. After GC cells were treated with combination of AZD1775 and olaparib at a fixed ratio of 1:200 (AZD1775: olaparib) for 48 h, cell viability were measured by CCK-8 assays and Fa-CI plots were made using the Chou-Talalay method. CI 1 indicated synergism, additivity, and antagonism, respectively. (TIF 206 kb
Soybean β51–63 peptide stimulates cholecystokinin secretion via a calcium-sensing receptor in enteroendocrine STC-1 cells
Full text linkWe previously demonstrated that intraduodenal administration of an arginine-rich β51-63 peptide in soybean β-conglycinin suppresses food intake via cholecystokinin (CCK) secretion in rats. However, the cellular mechanisms by which the β51-63 peptide induces CCK secretion remain to be clarified. In the present study, we examined whether the extracellular calcium-sensing receptor (CaR) mediates β51-63-induced CCK secretion in murine CCK-producing enteroendocrine cell line STC-1. CCK secretion and changes in intracellular Ca2+ concentration in response to β51-63 peptide were measured in STC-1 cells under various extracellular Ca2+ concentrations and after treatment with a CaR antagonist. Intracellular Ca2+ concentrations in response to β51-63 peptide and extracellular Ca2+ were also measured in CaR-expressing human embryonic kidney (HEK-293) cells. The β51-63 peptide induced CCK secretion and intracellular Ca2+ mobilization in STC-1 cells under normal (1.2 mM) extracellular Ca2+ conditions in a dose-dependent manner. These responses to β51-63 peptide were reduced by the removal of intra- or extracellular Ca2+ but enhanced by increasing extracellular Ca2+ concentrations. Intracellular Ca2+ mobilization induced by extracellular Ca2+ was also increased by the pretreatment with β51-63 peptide. Treatment with a specific CaR antagonist (NPS2143) inhibited β51-63-induced CCK secretion and intracellular Ca2+ mobilization. In addition, HEK-293 cells transfected with CaR acquired sensitivity to the β51-63 peptide. From these results, we conclude that CaR is the β51-63 peptide sensor responsible for the stimulation of CCK secretion in enteroendocrine STC-1 cells
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