GPR120 Regulates Pancreatic Polypeptide Secretion From Male Mouse Islets via PLC-Mediated Calcium Mobilization

Endocrinology ◽  
2020 ◽  
Vol 161 (10) ◽  
Author(s):  
Yu-Feng Zhao ◽  
Xiao-Cheng Li ◽  
Xiang-Yan Liang ◽  
Yan-Yan Zhao ◽  
Rong Xie ◽  
...  
Keyword(s):  
Pancreatic Polypeptide ◽  
Quantitative Polymerase Chain Reaction ◽  
Chow Diet ◽  
Specific Cell ◽  
Obese Mice ◽  
Normal Chow ◽  
Mouse Islets ◽  
Normal Chow Diet

Abstract The free fatty acid receptor G protein-coupled receptor 120 (GPR120) is expressed in pancreatic islets, but its specific cell distribution and function have not been fully established. In this study, a GPR120-IRES-EGFP knockin (KI) mouse was generated to identify GPR120-expressing cells with enhanced green fluorescence proteins (EGFP). EGFP-positive cells collected from KI mouse islets by flow cytometry had a significantly higher expression of pancreatic polypeptide (PP) evidenced by reverse transcriptase (RT)-quantitative polymerase chain reaction (qPCR). Single-cell RT-PCR and immunocytochemical double staining also demonstrated the coexpression of GPR120 with PP in mouse islets. The GPR120-specific agonist TUG-891 significantly increased plasma PP levels in mice. TUG-891 significantly increased PP levels in islet medium in vitro, which was markedly attenuated by GPR120 small interfering RNA treatment. TUG-891–stimulated PP secretion in islets was fully blocked by pretreatment with YM-254890 (a Gq protein inhibitor), U73122 (a phospholipase C inhibitor), or thapsigargin (an inducer of endoplasmic reticulum Ca2+ depletion), respectively. TUG-891 triggered the increase in intracellular free Ca2+ concentrations ([Ca2+]i) in PP cells, which was also eliminated by YM-254890, U73122, or thapsigargin. GPR120 gene expression was significantly reduced in islets of high-fat diet (HFD)-induced obese mice. TUG-891–stimulated PP secretion was also significantly diminished in vivo and in vitro in HFD-induced obese mice compared with that in normal-chow diet control mice. In summary, this study demonstrated that GPR120 is expressed in mouse islet PP cells and GPR120 activation stimulated PP secretion via the Gq/PLC-Ca2+ signaling pathway in normal-chow diet mice but with diminished effects in HFD-induced obese mice.

scholarly journals Adipocyte PHLPP2 inhibition prevents obesity-induced fatty liver

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
KyeongJin Kim ◽  
Jin Ku Kang ◽  
Young Hoon Jung ◽  
Sang Bae Lee ◽  
Raffaela Rametta ◽  
...  
Keyword(s):  
Fatty Liver ◽  
Whole Body ◽  
Acid Oxidation ◽  
Chow Diet ◽  
Peroxisome Proliferator ◽  
Obese Mice ◽  
Ph Domain ◽  
Peroxisome Proliferator Activated Receptor

AbstractIncreased adiposity confers risk for systemic insulin resistance and type 2 diabetes (T2D), but mechanisms underlying this pathogenic inter-organ crosstalk are incompletely understood. We find PHLPP2 (PH domain and leucine rich repeat protein phosphatase 2), recently identified as the Akt Ser473 phosphatase, to be increased in adipocytes from obese mice. To identify the functional consequence of increased adipocyte PHLPP2 in obese mice, we generated adipocyte-specific PHLPP2 knockout (A-PHLPP2) mice. A-PHLPP2 mice show normal adiposity and glucose metabolism when fed a normal chow diet, but reduced adiposity and improved whole-body glucose tolerance as compared to Cre- controls with high-fat diet (HFD) feeding. Notably, HFD-fed A-PHLPP2 mice show increased HSL phosphorylation, leading to increased lipolysis in vitro and in vivo. Mobilized adipocyte fatty acids are oxidized, leading to increased peroxisome proliferator-activated receptor alpha (PPARα)-dependent adiponectin secretion, which in turn increases hepatic fatty acid oxidation to ameliorate obesity-induced fatty liver. Consistently, adipose PHLPP2 expression is negatively correlated with serum adiponectin levels in obese humans. Overall, these data implicate an adipocyte PHLPP2-HSL-PPARα signaling axis to regulate systemic glucose and lipid homeostasis, and suggest that excess adipocyte PHLPP2 explains decreased adiponectin secretion and downstream metabolic consequence in obesity.

Metabolic in Vivo Labeling Highlights Differences of Metabolically Active Microbes from the Mucosal Gastrointestinal Microbiome between High-Fat and Normal Chow Diet

2017 ◽  
Vol 16 (4) ◽  
pp. 1593-1604 ◽  
Author(s):  
Andreas Oberbach ◽  
Sven-Bastiaan Haange ◽  
Nadine Schlichting ◽  
Marco Heinrich ◽  
Stefanie Lehmann ◽  
...  
Keyword(s):  
Chow Diet ◽  
High Fat ◽  
Gastrointestinal Microbiome ◽  
In Vivo Labeling ◽  
Normal Chow ◽  
Normal Chow Diet

scholarly journals Cardiac mTOR rescues the detrimental effects of diet-induced obesity in the heart after ischemia-reperfusion

2015 ◽  
Vol 308 (12) ◽  
pp. H1530-H1539 ◽  
Author(s):  
Toshinori Aoyagi ◽  
Jason K. Higa ◽  
Hiroko Aoyagi ◽  
Naaiko Yorichika ◽  
Briana K. Shimada ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Ex Vivo ◽  
Ischemia Reperfusion ◽  
Chow Diet ◽  
In Vivo Models ◽  
Myocardial Scarring ◽  
Diet Induced Obesity ◽  
Normal Chow ◽  
Normal Chow Diet

Diet-induced obesity deteriorates the recovery of cardiac function after ischemia-reperfusion (I/R) injury. While mechanistic target of rapamycin (mTOR) is a key mediator of energy metabolism, the effects of cardiac mTOR in ischemic injury under metabolic syndrome remains undefined. Using cardiac-specific transgenic mice overexpressing mTOR (mTOR-Tg mice), we studied the effect of mTOR on cardiac function in both ex vivo and in vivo models of I/R injury in high-fat diet (HFD)-induced obese mice. mTOR-Tg and wild-type (WT) mice were fed a HFD (60% fat by calories) for 12 wk. Glucose intolerance and insulin resistance induced by the HFD were comparable between WT HFD-fed and mTOR-Tg HFD-fed mice. Functional recovery after I/R in the ex vivo Langendorff perfusion model was significantly lower in HFD-fed mice than normal chow diet-fed mice. mTOR-Tg mice demonstrated better cardiac function recovery and had less of the necrotic markers creatine kinase and lactate dehydrogenase in both feeding conditions. Additionally, mTOR overexpression suppressed expression of proinflammatory cytokines, including IL-6 and TNF-α, in both feeding conditions after I/R injury. In vivo I/R models showed that at 1 wk after I/R, HFD-fed mice exhibited worse cardiac function and larger myocardial scarring along myofibers compared with normal chow diet-fed mice. In both feeding conditions, mTOR overexpression preserved cardiac function and prevented myocardial scarring. These findings suggest that cardiac mTOR overexpression is sufficient to prevent the detrimental effects of diet-induced obesity on the heart after I/R, by reducing cardiac dysfunction and myocardial scarring.

scholarly journals Dietary Curcumin Systemically Maintains Insulin Homeostasis in Diet-Induced Aged Obese Mice via Liver-Pancreas-Brain Axis

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 29-29
Author(s):  
Yoo Kim ◽  
Caio Henrique Mazucanti ◽  
Jennifer F. O'Connell ◽  
Josephine M. Egan
Keyword(s):  
Insulin Clearance ◽  
Chow Diet ◽  
Obese Mice ◽  
High Fat ◽  
Insulin Degrading Enzyme ◽  
Insulin Levels ◽  
High Sugar ◽  
Insulin Homeostasis ◽  
Normal Chow ◽  
Normal Chow Diet

Abstract Objectives Aging is a condition in which we gradually lose the ability to maintain homeostasis due to dysfunction. There continues to be a knowledge gap in implicating how dietary intervention affects the mechanisms delaying or preventing aging-related chronic diseases. Although curcumin (CUR), a natural antioxidant, shows the putative therapeutic properties such as reinstating insulin homeostasis in obese mice, an aging-associated mechanism in which CUR regulates insulin levels largely remains unclear. Thus, the objective of this study is to determine effects of CUR on anti-aging under obese condition mediated by maintaining insulin homeostasis via cross-talk among liver, pancreas and brain. Methods We examine how dietary CUR improves insulin clearance and maintains a proper range of circulating insulin level in the aged diet-induced obesity (DIO) mouse model. Old male C57BL/6J mice were fed a normal chow diet (NCD) or a NCD containing 0.4% (w/w) curcumin (NCD + CUR), a high fat/high sugar diet (HFHSD) or a HFHSD + CUR (N = 7–9 per group) for 16 weeks. Results Old male C57BL/6J mice were fed a normal chow diet (NCD) or a NCD containing 0.4% (w/w) curcumin (NCD + CUR), a high fat/high sugar diet (HFHSD) or a HFHSD + CUR (N = 7–9 per group) for 16 weeks. Mice given HFHSD + CUR had reduced body weight gain (4.7 ± 1.8 vs 7.8 ± 1.6g) and had lower blood insulin levels (2.24 ± 0.3 vs. 1.53 ± 0.3 ng/ml) under fasting conditions compared to mice on HFHSD alone, resulting from significantly improved insulin clearance via upregulation of hepatic insulin-degrading enzyme (IDE) and circulating IDE levels in serum. On the other hand, the expression of IDE gene in hypothalamus was significantly lower in HFHSD + CUR mice (1.3 folds) than HFHSD animals. Obesity induces hyperglycemic condition in brain by higher IDE expression to excessively break down insulin. We also observed significantly smaller islets of Langerhans (4.53 ± 0.72 vs 7.90 ± 0.34 a.u.) in HFSD + CUR fed mice and increased glucagon contents compared to HFS fed mice, indicating less secretion of insulin in pancreas under obese condition. Conclusions The conclusion of this study is that curcumin is a potent, natural therapeutic agent that can systemically regulate insulin levels in a multifaceted manner to protect against insulin resistance in aged mice. Funding Sources Intramural Research Program of NIAThe OTTOGI HAM TAIHO Foundation

Epithelial Organotypic Cultures: A Viable Model to Address Mechanisms of Carcinogenesis by Epitheliotropic Viruses

2018 ◽  
Vol 18 (4) ◽  
pp. 246-255 ◽  
Author(s):  
Lara Termini ◽  
Enrique Boccardo
Keyword(s):  
Three Dimensional ◽  
Cell Types ◽  
Experimental Models ◽  
Biological Research ◽  
Specific Gene ◽  
Specific Cell ◽  
Organotypic Cultures ◽  
Skin Physiology

In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.

scholarly journals Akt kinase LANCL2 functions as a key driver in EGFR-mutant lung adenocarcinoma tumorigenesis

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Yuqing Lou ◽  
Jianlin Xu ◽  
Yanwei Zhang ◽  
Wei Zhang ◽  
Xueyan Zhang ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Cell Line ◽  
Quantitative Polymerase Chain Reaction ◽  
Mutant Cell ◽  
A549 Cells ◽  
The Cancer Genome Atlas ◽  
Akt Kinase ◽  
Egfr Expression

AbstractEpidermal growth factor receptor (EGFR) is a key oncogene in lung adenocarcinoma (LUAD). Resistance to EGFR tyrosine kinase inhibitors is a major obstacle for EGFR-mutant LUAD patients. Our gene chip array, quantitative polymerase chain reaction validation, and shRNA-based high-content screening identified the Akt kinase lanthionine synthetase C-like protein 2 (LANCL2) as a pro-proliferative gene in the EGFR-mutant LUAD cell line PC9. Therefore, we investigated whether LANCL2 plays a role in promoting cell proliferation and drug resistance in EGFR-mutant LUAD. In silico clinical correlation analysis using the Cancer Genome Atlas Lung Adenocarcinoma dataset revealed a positive correlation between LANCL2 and EGFR expression and an inverse relationship between LANCL2 gain-of-function and survival in LUAD patients. The EGFR-mutant LUAD cell lines PC9 and HCC827 displayed higher LANCL2 expression than the non-EGFR-mutant cell line A549. In addition, LANCL2 was downregulated following gefitinib+pemetrexed combination therapy in PC9 cells. LANCL2 knockdown reduced proliferation and enhanced apoptosis in PC9, HCC827, and A549 cells in vitro and suppressed murine PC9 xenograft tumor growth in vivo. Notably, LANCL2 overexpression rescued these effects and promoted gefitinib + pemetrexed resistance in PC9 and HCC827 cells. Pathway analysis and co-immunoprecipitation followed by mass spectrometry of differentially-expressed genes in LANCL2 knockdown cells revealed enrichment of several cancer signaling pathways. In addition, Filamin A and glutathione S-transferase Mu 3 were identified as two novel protein interactors of LANCL2. In conclusion, LANCL2 promotes tumorigenic proliferation, suppresses apoptosis, and promotes gefitinib+pemetrexed resistance in EGFR-mutant LUAD cells. Based on the positive association between LANCL2, EGFR, and downstream Akt signaling, LANCL2 may be a promising new therapeutic target for EGFR-mutant LUAD.

scholarly journals Hepatic HuR protects against the pathogenesis of non-alcoholic fatty liver disease by targeting PTEN

2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Mi Tian ◽  
Jingjing Wang ◽  
Shangming Liu ◽  
Xinyun Li ◽  
Jingyuan Li ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Hepatic Steatosis ◽  
Chow Diet ◽  
Alcoholic Fatty Liver ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Pten Mrna ◽  
Normal Chow ◽  
Mice Liver

AbstractThe liver plays an important role in lipid and glucose metabolism. Here, we show the role of human antigen R (HuR), an RNA regulator protein, in hepatocyte steatosis and glucose metabolism. We investigated the level of HuR in the liver of mice fed a normal chow diet (NCD) and a high-fat diet (HFD). HuR was downregulated in the livers of HFD-fed mice. Liver-specific HuR knockout (HuRLKO) mice showed exacerbated HFD-induced hepatic steatosis along with enhanced glucose tolerance as compared with control mice. Mechanistically, HuR could bind to the adenylate uridylate-rich elements of phosphatase and tensin homolog deleted on the chromosome 10 (PTEN) mRNA 3′ untranslated region, resulting in the increased stability of Pten mRNA; genetic knockdown of HuR decreased the expression of PTEN. Finally, lentiviral overexpression of PTEN alleviated the development of hepatic steatosis in HuRLKO mice in vivo. Overall, HuR regulates lipid and glucose metabolism by targeting PTEN.

scholarly journals Rho GTPases as Key Molecular Players within Intestinal Mucosa and GI Diseases

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 66
Author(s):  
Rashmita Pradhan ◽  
Phuong A. Ngo ◽  
Luz d. C. Martínez-Sánchez ◽  
Markus F. Neurath ◽  
Rocío López-Posadas
Keyword(s):  
Intestinal Mucosa ◽  
Rho Gtpases ◽  
Current Knowledge ◽  
Cell Types ◽  
Effector Proteins ◽  
Special Focus ◽  
Specific Cell ◽  
Rho Proteins

Rho proteins operate as key regulators of the cytoskeleton, cell morphology and trafficking. Acting as molecular switches, the function of Rho GTPases is determined by guanosine triphosphate (GTP)/guanosine diphosphate (GDP) exchange and their lipidation via prenylation, allowing their binding to cellular membranes and the interaction with downstream effector proteins in close proximity to the membrane. A plethora of in vitro studies demonstrate the indispensable function of Rho proteins for cytoskeleton dynamics within different cell types. However, only in the last decades we have got access to genetically modified mouse models to decipher the intricate regulation between members of the Rho family within specific cell types in the complex in vivo situation. Translationally, alterations of the expression and/or function of Rho GTPases have been associated with several pathological conditions, such as inflammation and cancer. In the context of the GI tract, the continuous crosstalk between the host and the intestinal microbiota requires a tight regulation of the complex interaction between cellular components within the intestinal tissue. Recent studies demonstrate that Rho GTPases play important roles for the maintenance of tissue homeostasis in the gut. We will summarize the current knowledge on Rho protein function within individual cell types in the intestinal mucosa in vivo, with special focus on intestinal epithelial cells and T cells.

scholarly journals Discovery of novel mechanosensitive genes in vivo using mouse carotid artery endothelium exposed to disturbed flow

Blood ◽  
2010 ◽  
Vol 116 (15) ◽  
pp. e66-e73 ◽  
Author(s):  
Chih-Wen Ni ◽  
Haiwei Qiu ◽  
Amir Rezvan ◽  
Kihwan Kwon ◽  
Douglas Nam ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Ex Vivo ◽  
Expression Profiles ◽  
Quantitative Polymerase Chain Reaction ◽  
Gene Expression Profiles ◽  
Disturbed Flow ◽  
A Genome ◽  
Pattern Comparison

Abstract Recently, we showed that disturbed flow caused by a partial ligation of mouse carotid artery rapidly induces atherosclerosis. Here, we identified mechanosensitive genes in vivo through a genome-wide microarray study using mouse endothelial RNAs isolated from the flow-disturbed left and the undisturbed right common carotid artery. We found 62 and 523 genes that changed significantly by 12 hours and 48 hours after ligation, respectively. The results were validated by quantitative polymerase chain reaction for 44 of 46 tested genes. This array study discovered numerous novel mechanosensitive genes, including Lmo4, klk10, and dhh, while confirming well-known ones, such as Klf2, eNOS, and BMP4. Four genes were further validated for protein, including LMO4, which showed higher expression in mouse aortic arch and in human coronary endothelium in an asymmetric pattern. Comparison of in vivo, ex vivo, and in vitro endothelial gene expression profiles indicates that numerous in vivo mechanosensitive genes appear to be lost or dysregulated during culture. Gene ontology analyses show that disturbed flow regulates genes involved in cell proliferation and morphology by 12 hours, followed by inflammatory and immune responses by 48 hours. Determining the functional importance of these novel mechanosensitive genes may provide important insights into understanding vascular biology and atherosclerosis.

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