Leucine improves α-amylase secretion through the general secretory signaling pathway in pancreatic acinar cells of dairy calves

2020 ◽  
Vol 318 (6) ◽  
pp. C1284-C1293
Author(s):  
Long Guo ◽  
Huibin Tian ◽  
Junhu Yao ◽  
Hao Ren ◽  
Qinyan Yin ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Signaling Pathway ◽  
Citrate Synthase ◽  
Secretory Protein ◽  
Pancreatic Acinar Cells ◽  
Exocrine Function ◽  
Amylase Secretion ◽  
Label Free ◽  
Leucine Supplementation ◽  
Treatment Groups

The present study aimed to elucidate the mechanisms by which leucine impacts the secretion of pancreatic enzymes, especially amylase, by studying the proteomics profiles of pancreatic acinar (PA) cells from dairy cows. PA cells, the experimental model, were treated with four concentrations of leucine (0, 0.23, 0.45, and 0.90 mM). The abundance of different proteins in the four leucine treatment groups was detected. Label-free proteomic analysis enabled the identification of 1,906 proteins in all four treatment groups, and 1,350 of these proteins showed common expression across the groups. The primary effects of leucine supplementation were increased ( P < 0.05) citrate synthase and ATPase activity, which enlarged the cytosolic ATP pool, and the upregulation of secretory protein 61 (Sec61) expression, which promoted protein secretion. In summary, these results suggest that leucine increases citrate synthase in the TCA cycle and ATPase activity and promotes the Sec signaling pathway to increase the exocrine function of PA cells.

scholarly journals Anemoside B4 ameliorates TNBS-induced colitis through S100A9/MAPK/NF-κB signaling pathway

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yong Zhang ◽  
Zhengxia Zha ◽  
Wenhua Shen ◽  
Dan Li ◽  
Naixin Kang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Signaling Pathway ◽  
Tca Cycle ◽  
Mapk Signaling ◽  
Enzyme Linked Immunosorbent Assay ◽  
Trinitrobenzene Sulfonic Acid ◽  
Therapeutic Effects ◽  
Triterpenoid Saponin ◽  
Label Free

Abstract Background Despite the increased morbidity of ulcerative colitis (UC) in the developing countries, available treatments remain unsatisfactory. Therefore, it is urgent to discover more effective therapeutic strategies. Pulsatilla chinensis was widely used for the treatment of inflamed intestinal diseases including UC for thousands of years in China. Anemoside B4, the most abundant triterpenoid saponin isolated from P. chinensis, exerts anti-inflammatory and antioxidant effects and may be the most active compounds, which is responsible for the therapeutic effects. However, the mechanism how anemoside B4 executes its biological functions is still elusive. Methods Here, we used the 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis rat model to evaluate the therapeutic effect of anemoside B4. Blood samples of colitis rats were collected for hematology analysis. The inflammation-associated factors were investigated by enzyme-linked immunosorbent assay (ELISA). Cell proliferation and apoptosis was determined with EdU cell proliferation assay and TUNEL assay. The proteins regulated by anemoside B4 were identified by label-free quantitative proteomics. The significantly down-regulated proteins were verified by Western blotting analysis. mRNA expression was analyzed by quantitative real-time RT-PCR. Results The results showed that anemoside B4 ameliorated TNBS-induced colitis symptoms, including tissue damage, inflammatory cell infiltration, and pro-inflammatory cytokine production, apoptosis and slowed proliferation in colon. Quantitative proteomic analyses discovered that 56 proteins were significantly altered by anemoside B4 in the TNBS-induced rats. These proteins mainly clustered in tricarboxylic acid (TCA) cycle and respiratory electron transport chain. Among the altered proteins, S100A9 is one of the most significantly down-regulated proteins and associated with NF-κB and MAPK signaling pathways in the pathogenesis of UC. Further experiments revealed that anemoside B4 suppressed the expression of S100A9 and its downstream genes including TLR4 and NF-κB in colon. In vitro, anemoside B4 could inhibit the NF-κB signaling pathway induced by recombinant S100A9 protein in human intestinal epithelial Caco-2 cells. Moreover, anemoside B4 inhibits neutrophils recruitment and activation in colon induced by TNBS. Conclusions Our results demonstrate that anemoside B4 prevents TNBS-induced colitis by inhibiting the NF-κB signaling pathway through deactivating S100A9, suggesting that anemoside B4 is a promising therapeutic candidate for colitis.

Shortening velocity and ATPase activity of rat skeletal muscle fibers: effects of endurance exercise training

1994 ◽  
Vol 266 (6) ◽  
pp. C1699-C1713 ◽  
Author(s):  
J. M. Schluter ◽  
R. H. Fitts
Keyword(s):  
Atpase Activity ◽  
Endurance Exercise ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Treadmill Running ◽  
Type I ◽  
Marker Enzyme ◽  
Shortening Velocity

Mechanical properties were measured in single skinned fibers from rat hindlimb muscle to test the hypothesis that the fast type IIb fiber exhibits a higher maximal shortening velocity (Vo) than the fast type IIa fiber and that the difference is directly attributable to a higher myofibrillar adenosinetriphosphatase (ATPase) activity in the type IIb fiber. Additional measurements were made to test the hypotheses that regular endurance exercise increases and decreases the Vo of the type I and IIa fiber, respectively, and that the altered Vo is associated with a corresponding change in the fiber ATPase activity. Rats were exercised by 8-12 wk of treadmill running for 2 h/day, 5 day/wk, up a 15% grade at a speed of 27 m/min. Fiber Vo was determined by the slack test, and the ATPase was measured fluorometrically in the same fiber. The myosin isozyme profile of each fiber was subsequently determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The mean +/- SE Vo (7.9 +/- 0.22 fiber lengths/s) of the type IIb fiber was significantly greater than the type IIa fiber (4.4 +/- 0.21 fiber lengths/s), and the higher Vo was associated with a higher ATPase activity (927 +/- 70 vs. 760 +/- 60 microM.min-1.mm-3). The exercise program induced cardiac hypertrophy and an approximately twofold increase in the mitochondrial marker enzyme citrate synthase. Exercise had no effect on fiber diameter or peak tension per cross-sectional area in any fiber type, but, importantly, it significantly increased (23%) both the Vo and the ATPase activity of the slow type I fiber of the soleus.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Inhibitory effect of high leucine concentration on α-amylase secretion by pancreatic acinar cells: possible key factor of proteasome

2018 ◽  
Vol 38 (6) ◽  
Author(s):  
Long Guo ◽  
Baolong Liu ◽  
Chen Zheng ◽  
Hanxun Bai ◽  
Hao Ren ◽  
...  
Keyword(s):  
Amylase Activity ◽  
Acinar Cells ◽  
Inhibitory Effect ◽  
Proteasome Activity ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
High Concentration ◽  
Amylase Release ◽  
Cholecystokinin Receptor ◽  
Key Factor

The present study aimed to investigate whether leucine affects the pancreatic exocrine by controlling the antisecretory factor (AF) and cholecystokinin receptor (CCKR) expression as well as the proteasome activity in pancreatic acinar cells of dairy calves. The pancreatic acinar cells were isolated from newborn Holstein bull calves and cultured using the Dulbecco’s modified Eagle’s medium/nutrient mixture F12 Ham’s liquid (DMEM/F12). There were six treatments of leucine dosage including 0 (control), 0.23, 0.45, 1.35, 4.05, and 12.15 mM, respectively. After culture for 3 h, the samples were collected for subsequent analysis. As the leucine concentration increased from 0 to 1.35 mM, the α-amylase activity in media decreased significantly (P<0.05), while further increase in leucine concentration did not show any decrease in α-amylase activity. Addition of leucine inhibited (P<0.05) the expression of AF and CCKR, and decreased the activity of proteasome (P<0.05) by 76%, 63%, 24%, 7%, and 9%, respectively. Correlation analysis results showed α-amylase secretion was negatively correlated with leucine concentration (P<0.01), and positively correlated with proteasome activity (P<0.01) and the expression of CCK1R (P<0.01) and AF (P<0.05). The biggest regression coefficient was showed between α-amylase activity and proteasome (0.7699, P<0.001). After inhibition of proteasome by MG-132, low dosage leucine decreased (P<0.05) the activity of proteasome and α-amylase, as well as the expression of CCK1R. In conclusion, we demonstrated that the high-concentration leucine induced decrease in α-amylase release was mainly by decreasing proteasome activity.

Regulation of CCK-induced amylase release by PKC-δ in rat pancreatic acinar cells

2004 ◽  
Vol 287 (4) ◽  
pp. G764-G771 ◽  
Author(s):  
Chenwei Li ◽  
Xuequn Chen ◽  
John A. Williams
Keyword(s):  
Acinar Cells ◽  
Adenoviral Vectors ◽  
Dominant Negative ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
Wild Type ◽  
Amylase Release ◽  
Pkc Isoforms ◽  
Chemical Inhibitors ◽  
Dominant Negative Variant

PKC is known to be activated by pancreatic secretagogues such as CCK and carbachol and to participate along with calcium in amylase release. Four PKC isoforms, α, δ, ε, and ζ, have been identified in acinar cells, but which isoforms participate in amylase release are unknown. To identify the responsible isoforms, we used translocation assays, chemical inhibitors, and overexpression of individual isoforms and their dominant-negative variants by means of adenoviral vectors. CCK stimulation caused translocation of PKC-α, -δ, and -ε, but not -ζ from soluble to membrane fraction. CCK-induced amylase release was inhibited ∼30% by GF109203X, a broad spectrum PKC inhibitor, and by rottlerin, a PKC-δ inhibitor, but not by Gö6976, a PKC-α inhibitor, at concentrations from 1 to 5 μM. Neither overexpression of wild-type or dominant-negative PKC-α affected CCK-induced amylase release. Overexpression of PKC-δ and -ε enhanced amylase release, whereas only dominant-negative PKC-δ inhibited amylase release by 25%. PKC-δ overexpression increased amylase release at all concentrations of CCK, but dominant-negative PKC-δ only inhibited the maximal concentration; both similarly affected carbachol and JMV-180-induced amylase release. Overexpression of both PKC-δ and its dominant-negative variant affected the late but not the early phase of amylase release. GF109203X totally blocked the enhancement of amylase release by PKC-δ but had no further effect in the presence of dominant-negative PKC-δ. These results indicate that PKC-δ is the PKC isoform involved with amylase secretion.

scholarly journals Proteomic Analysis of Radiation-Induced Acute Liver Damage in a Rabbit Model

Dose-Response ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 155932581988950 ◽  
Author(s):  
Lingong Jiang ◽  
Huimin Jia ◽  
Zhicheng Tang ◽  
Xiaofei Zhu ◽  
Yangsen Cao ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Liver Damage ◽  
Rabbit Model ◽  
Mapk Signaling ◽  
Differentially Expressed ◽  
Mitogen Activated Protein Kinase ◽  
Differentially Expressed Proteins ◽  
Label Free ◽  
Radiation Induced ◽  
Liver Tissues

Radiation-induced liver damage (RILD) has become a limitation in radiotherapy for hepatocellular carcinoma. We established a rabbit model of RILD by CyberKnife. Electron microscopy analysis revealed obvious nuclear atrophy and disposition of fat in the nucleus after irradiation. We then utilized a mass spectrometry-based label-free relative quantitative proteomics approach to compare global proteomic changes of rabbit liver in response to radiation. In total, 2365 proteins were identified, including 338 proteins that were significantly dysregulated between irradiated and nonirradiated liver tissues. These differentially expressed proteins included USP47, POLR2A, CSTB, MCFD2, and CSNK2A1. Real-time polymerase chain reaction confirmed that USP47 and CABLES1 transcripts were significantly higher in irradiated liver tissues, whereas MCFD2 and CSNK2A1 expressions were significantly reduced. In Clusters of Orthologous Groups of proteins analysis, differentially expressed proteins were annotated and divided into 24 categories, including posttranslational modification, protein turnover, and chaperones. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the enriched pathways in dysregulated proteins included the vascular endothelial growth factors (VEGF) signaling pathway, the mitogen-activated protein kinase (MAPK) signaling pathway, and the adipocytokine signaling pathway. The identification of proteins and pathways is crucial toward elucidating the radiation response process of the liver, which may facilitate the discovery of novel therapeutic targets.

Changes in the exocrine pancreas secondary to altered small intestinal function in the CF mouse

2001 ◽  
Vol 281 (4) ◽  
pp. G899-G906 ◽  
Author(s):  
Robert C. De Lisle ◽  
Kathryn S. Isom ◽  
Donna Ziemer ◽  
Calvin U. Cotton
Keyword(s):  
Exocrine Pancreas ◽  
Exocrine Function ◽  
Amylase Secretion ◽  
Mrna Levels ◽  
Intestinal Function ◽  
Small Intestinal ◽  
First Time ◽  
Camp Levels

The exocrine pancreas of the cystic fibrosis (CF) mouse ( cftrm1UNC ) is only mildly affected compared with the human disease, providing a useful model to study alterations in exocrine function. The CF mouse pancreas has ∼50% of normal amylase levels and ∼200% normal Muclin levels, the major sulfated glycoprotein of the pancreas. Protein biosynthetic rates and mRNA levels for amylase were not altered in CF compared with normal mice, and increases in Muclin biosynthesis and mRNA paralleled the increased protein content. Stimulated pancreatic amylase secretion in vitro and in vivo tended to be increased in CF mice but was not statistically significant compared with normal mice. We show for the first time that the CF mouse duodenum is abnormally acidic (normal intestinal pH = 6.47 ± 0.05; CF intestinal pH = 6.15 ± 0.07) and hypothesize that this may result in increased signaling to the exocrine pancreas. There were significant increases in CF intestinal mRNA levels for secretin (310% of normal, P < 0.001) and vasoactive intestinal peptide (148% of normal, P < 0.05). Furthermore, CF pancreatic cAMP levels were 147% of normal ( P < 0.01). These data suggest that the CF pancreas may be chronically stimulated by cAMP-mediated signals, which in turn may exacerbate protein plugging in the acinar/ductal lumen, believed to be the primary cause of destruction of the pancreas in CF.

scholarly journals Mechanism and regulation of folate uptake by pancreatic acinar cells: effect of chronic alcohol consumption

2010 ◽  
Vol 298 (6) ◽  
pp. G985-G993 ◽  
Author(s):  
Hamid M. Said ◽  
Lisa Mee ◽  
V. Thillai Sekar ◽  
Balasubramaniem Ashokkumar ◽  
Stephen J. Pandol
Keyword(s):  
Acinar Cells ◽  
Pancreatic Acinar Cell ◽  
Pancreatic Acinar Cells ◽  
Exocrine Function ◽  
Acid Uptake ◽  
Human Pancreas ◽  
Chronic Alcohol ◽  
Transport Inhibitors ◽  
Pancreatic Exocrine ◽  
One Carbon Metabolism

Folate plays an essential role in one-carbon metabolism, and a relationship exists between methyl group metabolism and pancreatic exocrine function. Little, however, is known about the mechanism(s) and regulation of folate uptake by pancreatic acinar cells and the effect of chronic alcohol use on the process. We addressed these issues using the rat-derived pancreatic acinar cell line AR42J and freshly isolated primary rat pancreatic acinar cells as models. We found [3H]folic acid uptake to be 1) temperature and pH dependent with a higher uptake at acidic than at neutral/alkaline pH; 2) saturable as a function of substrate concentration at both buffer pH 7.4 and 6.0; 3) inhibited by folate structural analogs and by anion transport inhibitors at both buffer pH 7.4 and 6.0; 4) trans-stimulated by unlabeled folate; 5) adaptively regulated by the prevailing extracellular folate level, and 6) inhibited by modulators of the cAMP/PKA-mediated pathway. Both the reduced folate carrier (RFC) and the proton-coupled folate transporter (PCFT) were found to be expressed in AR42J and in primary pancreatic acinar cells, as well as in native human pancreas with expression of RFC being higher than PCFT. Chronic alcohol feeding of rats (4 wk; 36% of calories from ethanol) led to a significant decrease in folate uptake by freshly isolated primary pancreatic acinar cells compared with cells from pair-fed controls; this effect was associated with a parallel decrease in the level of expression of RFC and PCFT. These studies reveal that folate uptake by pancreatic acinar cells is via a regulated carrier-mediated process which may involve RFC and PCFT. In addition, chronic alcohol feeding leads to a marked inhibition in folate uptake by pancreatic acinar cells, an effect that is associated with reduction in level of expression of RFC and PCFT.

Stimulus–secretion coupling in exocrine pancreas: possible role of calmodulin

1981 ◽  
Vol 59 (9) ◽  
pp. 994-1001 ◽  
Author(s):  
Seymour Heisler ◽  
Laurence Chauvelot ◽  
Diane Desjardins ◽  
Christiane Noel ◽  
Herman Lambert ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Pancreatic Enzyme ◽  
Antidepressant Drugs ◽  
Enzyme Secretion ◽  
Pancreatic Acinar Cells ◽  
Secretory Process ◽  
Amylase Secretion ◽  
Enzyme Release ◽  
Mediated Effects ◽  
Pancreatic Enzyme Secretion

Many calcium-mediated effects in mammalian cells may be activated by calcium-calmodulin stimulated enzymes. These effects are inhibited by various antidepressant drugs which bind to and inactivate calmodulin. In the current study, calmodulin was identified by affinity chromatography and gel electrophoresis in the cytoplasm of dispersed rat pancreatic acinar cells. Its role in enzyme secretion was assessed by evaluating the effects of various antidepressant drugs on the enzyme secretory process. Chlorpromazine, trifluoperazine, thioridazine, chlorprothixene and amitriptyline inhibited amylase secretion stimulated by carbacol, A-23187, and cholecystokinin-pancreozymin but not that elicitied by dibutyryl cyclic AMP secretin or vasoactive intestinal peptide (VIP). Haloperidol, sulpiride, phenobarbital, and ethanol were without effect on secretagogue-stimulated enzyme release. Only those agents which blocked secretion also inhibited 45Ca release stimulated by carbachol from isotope preloaded cells. The data suggest that calmodulin may have a functional role in pancreatic enzyme secretion.

Influence of ractopamine hydrochloride supplementation on pancreatic digestive enzyme activity in finishing steers

2020 ◽  
Author(s):  
Ronald Trotta ◽  
Kasey Maddock Carlin ◽  
Kendall Swanson
Keyword(s):  
Digestive Enzyme ◽  
Serum Glucose ◽  
Exocrine Function ◽  
Blood Collection ◽  
Final Body Weight ◽  
Treatment Groups ◽  
Finishing Steers ◽  
Pancreatic Exocrine ◽  
Digestive Enzyme Activities ◽  
Ractopamine Hydrochloride

Sixty-nine finishing steers were randomly assigned to one of two treatment groups: supplementation to provide 0 (CON) or 267 mg d-1 of ractopamine hydrochloride (RAC) for 42 d. Twelve steers were slaughtered for tissue and blood collection. Final body weight (BW) tended to be greater with RAC supplementation. Ractopamine hydrochloride supplementation decreased liver mass as a percentage of BW. Pancreatic protein concentration, digestive enzyme activities, serum glucose and insulin concentrations were not influenced by RAC supplementation. Ractopamine hydrochloride supplementation decreased the pancreatic: α-amylase:trypsin and serum urea-N concentrations. These data suggest that RAC may influence pancreatic exocrine function in cattle.

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