Insulin secretion in health and disease: genomics, proteomics and single vesicle dynamics

2006 ◽  
Vol 34 (2) ◽  
pp. 247-250 ◽  
Author(s):  
G.A. Rutter ◽  
A. Varadi ◽  
T. Tsuboi ◽  
L. Parton ◽  
M. Ravier
Keyword(s):  
Insulin Secretion ◽  
Plasma Membranes ◽  
In Vitro Models ◽  
Type Ii ◽  
Β Cell ◽  
Altered Expression ◽  
Protein Levels ◽  
Cell Gene Expression ◽  
Insulin Dependent

Defective insulin secretion from pancreatic islet β-cells is a sine qua non of Type II (non-insulin-dependent) diabetes. Digital imaging analysis of the nanomechanics of individual exocytotic events, achieved using total internal reflection fluorescence microscopy, has allowed us to demonstrate that insulin is released via transient or ‘cavicapture’ events whereby the vesicle and plasma membranes fuse transiently and reversibly. Such studies reveal that an increase in the number of abortive fusion events contributes to defective insulin secretion in in vitro models of Type II diabetes. Complementary analyses of genome-wide changes in β-cell gene expression, at both the mRNA and protein levels, are now facilitating the identification of key molecular players whose altered expression may contribute to the secretory defects in the diabetic β-cell.

scholarly journals Insulin secretion in health and disease: nutrients dictate the pace

2015 ◽  
Vol 75 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Romano Regazzi ◽  
Adriana Rodriguez-Trejo ◽  
Cécile Jacovetti
Keyword(s):  
Fatty Acids ◽  
Insulin Secretion ◽  
Cell Mass ◽  
Insulin Biosynthesis ◽  
Β Cells ◽  
Β Cell ◽  
Altered Expression ◽  
Cell Dysfunction ◽  
Dietary Nutrients ◽  
Underlying Mechanisms

Insulin is a key hormone controlling metabolic homeostasis. Loss or dysfunction of pancreatic β-cells lead to the release of insufficient insulin to cover the organism needs, promoting diabetes development. Since dietary nutrients influence the activity of β-cells, their inadequate intake, absorption and/or utilisation can be detrimental. This review will highlight the physiological and pathological effects of nutrients on insulin secretion and discuss the underlying mechanisms. Glucose uptake and metabolism in β-cells trigger insulin secretion. This effect of glucose is potentiated by amino acids and fatty acids, as well as by entero-endocrine hormones and neuropeptides released by the digestive tract in response to nutrients. Glucose controls also basal and compensatory β-cell proliferation and, along with fatty acids, regulates insulin biosynthesis. If in the short-term nutrients promote β-cell activities, chronic exposure to nutrients can be detrimental to β-cells and causes reduced insulin transcription, increased basal secretion and impaired insulin release in response to stimulatory glucose concentrations, with a consequent increase in diabetes risk. Likewise, suboptimal early-life nutrition (e.g. parental high-fat or low-protein diet) causes altered β-cell mass and function in adulthood. The mechanisms mediating nutrient-induced β-cell dysfunction include transcriptional, post-transcriptional and translational modifications of genes involved in insulin biosynthesis and secretion, carbohydrate and lipid metabolism, cell differentiation, proliferation and survival. Altered expression of these genes is partly caused by changes in non-coding RNA transcripts induced by unbalanced nutrient uptake. A better understanding of the mechanisms leading to β-cell dysfunction will be critical to improve treatment and find a cure for diabetes.

scholarly journals Biological Relevance of Colony Morphology and Phenotypic Switching by Burkholderia pseudomallei

2006 ◽  
Vol 189 (3) ◽  
pp. 807-817 ◽  
Author(s):  
Narisara Chantratita ◽  
Vanaporn Wuthiekanun ◽  
Khaemaporn Boonbumrung ◽  
Rachaneeporn Tiyawisutsri ◽  
Mongkol Vesaratchavest ◽  
...  
Keyword(s):  
Burkholderia Pseudomallei ◽  
Vaccine Development ◽  
Colony Morphology ◽  
Phenotypic Switching ◽  
Type I ◽  
Type Ii ◽  
Altered Expression ◽  
Replication Fitness

ABSTRACT Melioidosis is a notoriously protracted illness and is difficult to cure. We hypothesize that the causative organism, Burkholderia pseudomallei, undergoes a process of adaptation involving altered expression of surface determinants which facilitates persistence in vivo and that this is reflected by changes in colony morphology. A colony morphotyping scheme and typing algorithm were developed using clinical B. pseudomallei isolates. Morphotypes were divided into seven types (denoted I to VII). Type I gave rise to other morphotypes (most commonly type II or III) by a process of switching in response to environmental stress, including starvation, iron limitation, and growth at 42°C. Switching was associated with complex shifts in phenotype, one of which (type I to type II) was associated with a marked increase in production of factors putatively associated with in vivo concealment. Isogenic types II and III, derived from type I, were examined using several experimental models. Switching between isogenic morphotypes occurred in a mouse model, where type II appeared to become adapted for persistence in a low-virulence state. Isogenic type II demonstrated a significant increase in intracellular replication fitness compared with parental type I after uptake by epithelial cells in vitro. Isogenic type III demonstrated a higher replication fitness following uptake by macrophages in vitro, which was associated with a switch to type II. Mixed B. pseudomallei morphologies were common in individual clinical specimens and were significantly more frequent in samples of blood, pus, and respiratory secretions than in urine and surface swabs. These findings have major implications for therapeutics and vaccine development.

scholarly journals Disruption of the Dopamine D2 Receptor Impairs Insulin Secretion and Causes Glucose Intolerance

Endocrinology ◽  
2010 ◽  
Vol 151 (4) ◽  
pp. 1441-1450 ◽  
Author(s):  
Isabel García-Tornadú ◽  
Ana M. Ornstein ◽  
Astrid Chamson-Reig ◽  
Michael B. Wheeler ◽  
David J. Hill ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Intolerance ◽  
Dopamine D2 Receptor ◽  
D2 Receptor ◽  
Insulin Response ◽  
Wild Type ◽  
Β Cell ◽  
Insulin Response To Glucose

The relationship between antidopaminergic drugs and glucose has not been extensively studied, even though chronic neuroleptic treatment causes hyperinsulinemia in normal subjects or is associated with diabetes in psychiatric patients. We sought to evaluate dopamine D2 receptor (D2R) participation in pancreatic function. Glucose homeostasis was studied in D2R knockout mice (Drd2−/−) mice and in isolated islets from wild-type and Drd2−/− mice, using different pharmacological tools. Pancreas immunohistochemistry was performed. Drd2−/− male mice exhibited an impairment of insulin response to glucose and high fasting glucose levels and were glucose intolerant. Glucose intolerance resulted from a blunted insulin secretory response, rather than insulin resistance, as shown by glucose-stimulated insulin secretion tests (GSIS) in vivo and in vitro and by a conserved insulin tolerance test in vivo. On the other hand, short-term treatment with cabergoline, a dopamine agonist, resulted in glucose intolerance and decreased insulin response to glucose in wild-type but not in Drd2−/− mice; this effect was partially prevented by haloperidol, a D2R antagonist. In vitro results indicated that GSIS was impaired in islets from Drd2−/− mice and that only in wild-type islets did dopamine inhibit GSIS, an effect that was blocked by a D2R but not a D1R antagonist. Finally, immunohistochemistry showed a diminished pancreatic β-cell mass in Drd2−/− mice and decreased β-cell replication in 2-month-old Drd2−/− mice. Pancreatic D2Rs inhibit glucose-stimulated insulin release. Lack of dopaminergic inhibition throughout development may exert a gradual deteriorating effect on insulin homeostasis, so that eventually glucose intolerance develops.

scholarly journals Determining the Effect of Pterostilbene on Insulin Secretion Using Chemoproteomics

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2885
Author(s):  
Chiara Cassiano ◽  
Daniela Eletto ◽  
Alessandra Tosco ◽  
Raffaele Riccio ◽  
Maria Chiara Monti ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Pancreatic Beta Cells ◽  
Metabolic Disorders ◽  
Therapeutic Potential ◽  
Pharmacological Profile ◽  
Biological Targets ◽  
Cell Assays ◽  
Potential Applications ◽  
Insulin Dependent

Pterostilbene, the 3,5-dimethoxy derivative of resveratrol, is a well-known polyphenolic compound, mainly found in blueberries, grapevines, and Pterocarpus marsupium heartwood, which has recently attracted a great deal of attention due to its wide bio-pharmacological profile. Moreover, pterostilbene is more lipophilic than resveratrol, with a consequently better bioavailability and a more interesting therapeutic potential. In this work, a chemoproteomic approach, based on affinity chromatography, was applied on pterostilbene in the attempt to identify the biological targets responsible for its bioactivity. On this basis, syntaxins, a group of proteins involved in the formation of SNARE complexes mediating vesicles exocytosis, were selected among the most interesting pterostilbene interactors. In vitro and in cell assays gave evidence of the pterostilbene ability to reduce insulin secretion on glucose-stimulated pancreatic beta cells, opening the way to potential applications of pterostilbene as a supplement in the care of insulin-dependent metabolic disorders.

scholarly journals MANAGEMENT OF ENDOCRINE DISEASE: Cystic fibrosis-related diabetes: novel pathogenic insights opening new therapeutic avenues

2015 ◽  
Vol 172 (4) ◽  
pp. R131-R141 ◽  
Author(s):  
Raquel Barrio
Keyword(s):  
Cystic Fibrosis ◽  
Insulin Secretion ◽  
Synergistic Effects ◽  
Ionic Composition ◽  
Cell Mass ◽  
Β Cell ◽  
Gene Encoding ◽  
Mutant Proteins ◽  
Cf Transmembrane Conductance Regulator

Cystic fibrosis (CF) is a recessive genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR).CFTRis primarily present in epithelial cells of the airways, intestine and in cells with exocrine and endocrine functions. Mutations in the gene encoding the channel protein complex (CFTR) cause alterations in the ionic composition of secretions from the lung, gastrointestinal tract, liver, and also the pancreas. CF-related diabetes (CFRD), the most common complication of CF, has a major detrimental impact on pulmonary function, nutrition and survival. Glucose derangements in CF seem to start from early infancy and, even when the pathophysiology is multifactorial, insulin insufficiency is clearly a major component. Consistently, recent evidence has confirmed that CFTR is an important regulator of insulin secretion by islet β-cells. In addition, several other mechanisms were also recognized from cellular and animals models also contributing to either β-cell mass reduction or β-cell malfunction. Understanding such mechanisms is crucial for the development of the so-called ‘transformational’ therapies in CF, including the preservation of insulin secretion. Innovative therapeutic approaches aim to modify specific CFTR mutant proteins or positively modulate their function. CFTR modulators have recently shownin vitrocapacity to enhance insulin secretion and thereby potential clinical utility in CFDR, including synergistic effects between corrector and potentiator drugs. The introduction of incretins and the optimization of exocrine pancreatic replacement complete the number of therapeutic options of CFRD besides early diagnosis and implementation of insulin therapy. This review focuses on the recently identified pathogenic mechanisms leading to CFRD relevant for the development of novel pharmacological avenues in CFRD therapy.

scholarly journals Irisin Recovers Osteoarthritic Chondrocytes In Vitro

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1478 ◽  
Author(s):  
Gianluca Vadalà ◽  
Giuseppina Di Giacomo ◽  
Luca Ambrosio ◽  
Francesca Cannata ◽  
Claudia Cicione ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Protein Quantification ◽  
Saline Control ◽  
Collagen Gene ◽  
Type Ii ◽  
Protein Levels ◽  
Collagen Gene Expression ◽  
Osteoarthritic Chondrocytes

Physical exercise favors weight loss and ameliorates articular pain and function in patients suffering from osteoarthritis. Irisin, a myokine released upon muscle contraction, has demonstrated to yield anabolic effects on different cell types. This study aimed to investigate the effect of irisin on human osteoarthritic chondrocytes (hOAC) in vitro. Our hypothesis was that irisin would improve hOAC metabolism and proliferation. Cells were cultured in growing media and then exposed to either phosphate-buffered saline (control group) or human recombinant irisin (experimental group). Cell proliferation, glycosaminoglycan content, type II/X collagen gene expression and protein quantification as well as p38/extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK), protein kinase B (Akt), c-Jun N-terminal kinase (JNK), and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) involvement were evaluated. Furthermore, gene expression of interleukin (IL)-1 and -6, matrix metalloproteinase (MMP)-1 and -13, inducible nitric oxide synthase (iNOS), and tissue inhibitor of matrix metalloproteinases (TIMP)-1 and -3 were investigated following irisin exposure. Irisin increased hOAC cell content and both type II collagen gene expression and protein levels, while decreased type X collagen gene expression and protein levels. Moreover, irisin decreased IL-1, IL-6, MMP-1, MMP-13 and iNOS gene expression, while increased TIMP-1 and TIMP-3 levels. These effects seemed to be mediated by inhibition of p38, Akt, JNK and NFκB signaling pathways. The present study suggested that irisin may stimulate hOAC proliferation and anabolism inhibiting catabolism through p38, Akt, JNK, and NFκB inactivation in vitro, demonstrating the existence of a cross-talk between muscle and cartilage.

scholarly journals Insulinotropic and β-cell protective action of cuminaldehyde, cuminol and an inhibitor isolated from Cuminum cyminum in streptozotocin-induced diabetic rats

2013 ◽  
Vol 110 (8) ◽  
pp. 1434-1443 ◽  
Author(s):  
Swapnil B. Patil ◽  
Shreehari S. Takalikar ◽  
Madhav M. Joglekar ◽  
Vivek S. Haldavnekar ◽  
Akalpita U. Arvindekar
Keyword(s):  
Insulin Secretion ◽  
Protective Action ◽  
Diabetic Rats ◽  
Probable Mechanism ◽  
Bioactive Components ◽  
Β Cell ◽  
Cuminum Cyminum ◽  
Insulin Secretagogue ◽  
Ether Fraction

Cuminum cyminum, a commonly used spice, is known to have anti-diabetic action. The present study aims towards the isolation of bioactive components from C. cyminum and the evaluation of their insulin secretagogue potential with the probable mechanism and β-cell protective action. The anti-diabetic activity was detected in the petroleum ether (pet ether) fraction of the C. cyminum distillate and studied through in vivo and in vitro experiments. Bioactive components were identified through GC–MS, Fourier transform infrared spectroscopy and NMR analysis. The isolated components were evaluated for their insulin secretagogue action using rat pancreatic islets. Further, the probable mechanism of stimulation of islets was evaluated through in vitro studies using diazoxide, nifedipine and 3-isobutyl-1-methylxanthine. β-Cell protection was evaluated using the (1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan) (MTT) assay, the alkaline comet assay and nitrite production. The administration of the pet ether fraction for 45 d to streptozotocin-induced diabetic rats revealed an improved lipid profile. Cuminaldehyde and cuminol were identified as potent insulinotrophic components. Cuminaldehyde and cuminol (25 μg/ml) showed 3·34- and 3·85-fold increased insulin secretion, respectively, than the 11·8 mm-glucose control. The insulinotrophic action of both components was glucose-dependent and due to the closure of the ATP-sensitive K (K+-ATP) channel and the increase in intracellular Ca2+ concentration. An inhibitor of insulin secretion with potent β-cell protective action was also isolated from the same pet ether fraction. In conclusion, C. cyminum was able to lower blood glucose without causing hypoglycaemia or β-cell burn out. Hence, the commonly used spice, C. cyminum, has the potential to be used as a novel insulinotrophic therapy for prolonged treatment of diabetes.

scholarly journals Insulin secretion stimulated by l-arginine and its metabolite l-ornithine depends on Gαi2

2014 ◽  
Vol 307 (9) ◽  
pp. E800-E812 ◽  
Author(s):  
Veronika Leiss ◽  
Katarina Flockerzie ◽  
Ana Novakovic ◽  
Michaela Rath ◽  
Annika Schönsiegel ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Amino Acid ◽  
Metabolic Phenotype ◽  
Β Cells ◽  
Β Cell ◽  
Glucose Challenge ◽  
Intracellular Ca ◽  
Plasma Insulin Levels

Bordetella pertussis toxin (PTx), also known as islet-activating protein, induces insulin secretion by ADP-ribosylation of inhibitory G proteins. PTx-induced insulin secretion may result either from inactivation of Gαo proteins or from combined inactivation of Gαo, Gαi1, Gαi2, and Gαi3 isoforms. However, the specific role of Gαi2 in pancreatic β-cells still remains unknown. In global (Gαi2−/−) and β-cell-specific (Gαi2βcko) gene-targeted Gαi2 mouse models, we studied glucose homeostasis and islet functions. Insulin secretion experiments and intracellular Ca2+ measurements were used to characterize Gαi2 function in vitro. Gαi2−/− and Gαi2βcko mice showed an unexpected metabolic phenotype, i.e., significantly lower plasma insulin levels upon intraperitoneal glucose challenge in Gαi2−/− and Gαi2βcko mice, whereas plasma glucose concentrations were unchanged in Gαi2−/− but significantly increased in Gαi2βcko mice. These findings indicate a novel albeit unexpected role for Gαi2 in the expression, turnover, and/or release of insulin from islets. Detection of insulin secretion in isolated islets did not show differences in response to high (16 mM) glucose concentrations between control and β-cell-specific Gαi2-deficient mice. In contrast, the two- to threefold increase in insulin secretion evoked by l-arginine or l-ornithine (in the presence of 16 mM glucose) was significantly reduced in islets lacking Gαi2. In accord with a reduced level of insulin secretion, intracellular calcium concentrations induced by the agonistic amino acid l-arginine did not reach control levels in β-cells. The presented analysis of gene-targeted mice provides novel insights in the role of β-cell Gαi2 showing that amino acid-induced insulin-release depends on Gαi2.

Effect of gliclazide treatment on insulin secretion and β-cell mass in non-insulin dependent diabetic Goto–Kakisaki rats

1998 ◽  
Vol 361 (2-3) ◽  
pp. 243-251 ◽  
Author(s):  
Nathalie Dachicourt ◽  
Danielle Bailbé ◽  
Marie-Noelle Gangnerau ◽  
Patricia Serradas ◽  
Denis Ravel ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Cell Mass ◽  
Β Cell ◽  
Insulin Dependent ◽  
Insulin Dependent Diabetic

Effects of overexpression of pancreatic derived factor (FAM3B) in isolated mouse islets and insulin-secreting βTC3 cells

2005 ◽  
Vol 289 (4) ◽  
pp. E543-E550 ◽  
Author(s):  
Xiaopei Cao ◽  
Jichun Yang ◽  
Brant R. Burkhardt ◽  
Zhiyong Gao ◽  
Ryan K. Wong ◽  
...  
Keyword(s):  
Propidium Iodide ◽  
Annexin V ◽  
Full Length ◽  
Β Cell ◽  
High Potassium ◽  
Fluorescent Intensity ◽  
Fourfold Increase ◽  
Protein Levels ◽  
Mouse Islets

PANcreatic DERived factor (PANDER, FAM3B) is a recently discovered islet-specific cytokine. We have previously shown that, in vitro, truncated recombinant PANDER isoforms (20 and 21 kDa) are cytotoxic to β-cell lines but the effects of full-length PANDER on islet biology remain unclear. In this study, we used adenovirus (Ad-PANDER) to overexpress full-length cDNA of PANDER in islets and βTC3 cells. βTC3 cells were infected with Ad-PANDER or control vector. After 48 h, cell viability was significantly decreased as evaluated by MTT assay. The number of dead cells was significantly increased as indicated by the fluorescent intensity of the propidium iodide-stained cells (160 ± 13 vs. control 100 ± 7%, P = 0.001). Flow cytometric Tunel assay showed that overexpressing PANDER induced a significant fourfold increase in β-cell apoptosis (19.4 ± 6.3 vs. control 4.1 ± 0.8%, P < 0.05). There was a significant increase in the number of annexin V-positive (apoptotic) cells and propidium iodide-positive (dead) cells in mouse islets infected with Ad-PANDER compared with control cells infected with Ad-LacZ. Addition of 4 nM recombinant PANDER protein to βTC3 cells or infection of Ad-PANDER did not affect Akt and STAT1 phosphorylation, Bcl-2, Fas, and NF-κB protein levels. However, activation of caspase-3 was observed in βTC3 and islets infected with Ad-PANDER. Overexpression of PANDER in mouse islets or addition of recombinant PANDER decreased insulin secretion induced by carbachol plus glucose or high potassium but not that by glucose alone. Culture with recombinant PANDER did not affect glucose-induced NAD(P)H elevation in mouse islets. In conclusion, Ad-PANDER infection is as effective as truncated recombinant PANDER to induce βTC3 cell and mouse islet apoptosis.

Sign in / Sign up

Export Citation Format

Share Document