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Pompa M, Panunzi S, Borri A, De Gaetano A. A comparison among three maximal mathematical models of the glucose-insulin system. PLoS One 2021; 16:e0257789. [PMID: 34570804 PMCID: PMC8476045 DOI: 10.1371/journal.pone.0257789] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/13/2021] [Indexed: 11/24/2022] Open
Abstract
The most well-known and widely used mathematical representations of the physiology of a diabetic individual are the Sorensen and Hovorka models as well as the UVAPadova Simulator. While the Hovorka model and the UVAPadova Simulator only describe the glucose metabolism of a subject with type 1 diabetes, the Sorensen model was formulated to simulate the behaviour of both normal and diabetic individuals. The UVAPadova model is the most known model, accepted by the FDA, with a high level of complexity. The Hovorka model is the simplest of the three models, well documented and used primarily for the development of control algorithms. The Sorensen model is the most complete, even though some modifications were required both to the model equations (adding useful compartments for modelling subcutaneous insulin delivery) and to the parameter values. In the present work several simulated experiments, such as IVGTTs and OGTTs, were used as tools to compare the three formulations in order to establish to what extent increasing complexity translates into richer and more correct physiological behaviour. All the equations and parameters used for carrying out the simulations are provided.
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Affiliation(s)
- Marcello Pompa
- CNR-IASI, Laboratorio di Biomatematica, Consiglio Nazionale delle Ricerche, Istituto di Analisi dei Sistemi ed Informatica, Rome, Italy
- Università Cattolica del Sacro Cuore Rome, Rome, Italy
| | - Simona Panunzi
- CNR-IASI, Laboratorio di Biomatematica, Consiglio Nazionale delle Ricerche, Istituto di Analisi dei Sistemi ed Informatica, Rome, Italy
| | - Alessandro Borri
- CNR-IASI, Laboratorio di Biomatematica, Consiglio Nazionale delle Ricerche, Istituto di Analisi dei Sistemi ed Informatica, Rome, Italy
| | - Andrea De Gaetano
- CNR-IASI, Laboratorio di Biomatematica, Consiglio Nazionale delle Ricerche, Istituto di Analisi dei Sistemi ed Informatica, Rome, Italy
- CNR-IRIB, Consiglio Nazionale delle Ricerche, Istituto per la Ricerca e l’Innovazione Biomedica Palermo, Palermo, Italy
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Scavuzzo CJ, Newman LA, Gold PE, Korol DL. Extracellular levels of glucose in the hippocampus and striatum during maze training for food or water reward in male rats. Behav Brain Res 2021; 411:113385. [PMID: 34048874 PMCID: PMC8238909 DOI: 10.1016/j.bbr.2021.113385] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 05/15/2021] [Accepted: 05/22/2021] [Indexed: 12/19/2022]
Abstract
Glucose potently enhances cognitive functions whether given systemically or directly to the brain. The present experiments examined changes in brain extracellular glucose levels while rats were trained to solve hippocampus-sensitive place or striatum-sensitive response learning tasks for food or water reward. Because there were no task-related differences in glucose responses, the glucose results were pooled across tasks to form combined trained groups. During the first 1-3 min of training for food reward, glucose levels in extracellular fluid (ECF) declined significantly in the hippocampus and striatum; the declines were not seen in untrained, rewarded rats. When trained for water reward, similar decreases were observed in both brain areas, but these findings were less consistent than those seen with food rewards. After the initial declines in ECF glucose levels, glucose increased in most groups, approaching asymptotic levels ∼15-30 min into training. Compared to untrained food controls, training with food reward resulted in significant glucose increases in the hippocampus but not striatum; striatal glucose levels exhibited large increases to food intake in both trained and untrained groups. In rats trained to find water, glucose levels increased significantly above the values seen in untrained rats in both hippocampus and striatum. The decreases in glucose early in training might reflect an increase in brain glucose consumption, perhaps triggering increased brain uptake of glucose from blood, as evident in the increases in glucose later in training. The increased brain uptake of glucose may provide additional neuronal metabolic substrate for metabolism or provide astrocytic substrate for production of glycogen and lactate.
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Affiliation(s)
- C J Scavuzzo
- Department of Psychology, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada.
| | - L A Newman
- Department of Psychological Science, Vassar College, 124 Raymond Avenue, Box 713, Poughkeepsie, NY, 12604, United States
| | - P E Gold
- Department of Biology, Syracuse University, Syracuse, NY, 13244, United States
| | - D L Korol
- Department of Biology, Syracuse University, Syracuse, NY, 13244, United States.
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Díaz-Granados VH, López-López JM, Flores-Sánchez J, Olguin-Alor R, Bedoya-López A, Dinkova TD, Salazar-Díaz K, Vázquez-Santana S, Vázquez-Ramos JM, Lara-Núñez A. Glucose modulates proliferation in root apical meristems via TOR in maize during germination. Plant Physiol Biochem 2020; 155:126-135. [PMID: 32745931 DOI: 10.1016/j.plaphy.2020.07.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/08/2020] [Accepted: 07/21/2020] [Indexed: 05/25/2023]
Abstract
The Glucose-Target of Rapamycin (Glc-TOR) pathway has been studied in different biological systems, but scarcely during early seed germination. This work examines its importance for cell proliferation, expression of cell cycle key genes, their protein levels, besides morphology and cellularization of the root apical meristem of maize (Zea mays) embryo axes during germination under the influence of two simple sugars, glucose and sucrose, and a specific inhibitor of TOR activity, AZD 8055. The two sugars promote germination similarly and to an extent, independently of TOR activity. However, the Glc-TOR pathway increases the number of cells committed to proliferation, increasing the expression of a cell cycle gene, ZmCycD4;2, a putative G1/S regulator. Also, Glc-TOR may have influence on the protein stability of another G1/S cyclin, ZmCycD3, but had no influence on ZmCDKA;1 or ZmKRP3 or their proteins. Results suggest that the Glc-TOR pathway participates in the regulation of proliferation through different mechanisms that, in the end, modify the timing of seed germination.
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Affiliation(s)
- Víctor Hugo Díaz-Granados
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Jorge Manuel López-López
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Jesús Flores-Sánchez
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Roxana Olguin-Alor
- Laboratorio Nacional de Citometría de Flujo, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Andrea Bedoya-López
- Laboratorio Nacional de Citometría de Flujo, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Tzvetanka D Dinkova
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Kenia Salazar-Díaz
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Sonia Vázquez-Santana
- Facultad de Ciencias, Departamento de Biología Comparada, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Jorge Manuel Vázquez-Ramos
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Aurora Lara-Núñez
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
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Sanchez‐Andres JV, Pomares R, Malaisse WJ. Adaptive short-term associative conditioning in the pancreatic β-cell. Physiol Rep 2020; 8:e14403. [PMID: 32232927 PMCID: PMC7105902 DOI: 10.14814/phy2.14403] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 01/21/2023] Open
Abstract
This study associates cholinergic stimulation of the pancreatic β-cell electrical activity with a short-term memory phenomenon. Glucose pulses applied to a basal glucose concentration induce depolarizing waves which are used to estimate the evolution of the β-cell glucose sensitivity. Exposure to carbamoylcholine (carbachol) increases the size of the glucose-induced depolarizing waves. This change appears after carbachol withdrawal and implies a temporal potentiation of sensitivity (TPS) lasting up to one hour. TPS induction requires the simultaneous action of carbachol and glucose. The substitution of glucose with the secretagogues glyceraldehyde or 2-ketoisocaproate mimics glucose-induced TPS, while palmitate does not. TPS is not produced if the membrane is kept hyperpolarized by diazoxide. Glucose can be replaced by tolbutamide, suggesting a role of depolarization and a subsequent increase in intracellular calcium concentration. A role for kinases is suggested because staurosporine prevents TPS induction. Cycloheximide does not impair TPS induction, indicating that de novo protein synthesis is not required. The fact that the two inputs acting simultaneously produce an effect that lasts up to one hour without requiring de novo protein synthesis suggests that TPS constitutes a case of short-term associative conditioning in non-neural tissue. The convergence of basal glucose levels and muscarinic activation happens physiologically during the cephalic phase of digestion, in order to later absorb incoming fuels. Our data reveals that the role of the cephalic phase may be extended, increasing nutrient sensitivity during meals while remaining low between them.
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Affiliation(s)
| | - Raquel Pomares
- Department of PhysiologyUniversidad Miguel HernandezAlicanteSpain
| | - Willy J. Malaisse
- Department of BiochemistryUniversité Libre de BruxellesBrusselsBelgium
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Samii SS, Rico JE, Mathews AT, Davis AN, Orndorff CL, Aromeh LO, McFadden JW. Effects of body condition score on direct and indirect measurements of insulin sensitivity in periparturient dairy cows. Animal 2019; 13:2547-2555. [PMID: 31104643 DOI: 10.1017/s175173111900065x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Reductions in insulin sensitivity in periparturient dairy cows develop as a means to support lactation; however, excessive mobilization of fatty acids (FA) increases the risk for peripartal metabolic disorders. Our objectives were to investigate the effect of prepartum body condition score (BCS) on systemic glucose and insulin tolerance, and to compare direct and indirect measurements of insulin sensitivity in peripartal lean and overweight dairy cows. Fourteen multiparous Holstein cows were allocated into two groups according to their BCS at day -28 prepartum: lean (n = 7; BCS ≤ 3.0) or overweight; (n = 7; BCS ≥ 4.0). Liver biopsies were performed on day -27, -14 and 4, relative to expected parturition. Intravenous insulin or glucose tolerances tests were performed following each liver biopsy. Relative to lean cows, overweight cows exhibited lower dry matter intake, lost more BCS and displayed increased plasma FA and β-hydroxybutyrate concentrations and elevated liver lipid content during peripartum. Glucose clearance rate was lower for all cows postpartum. Prepartum BCS had minimal effects on insulin and glucose tolerance; however, the ability of the cow to restore blood glucose levels following an insulin challenge was suppressed by increased BCS. Glucose-dependent parameters of insulin and glucose tolerance were not correlated with surrogate indices of insulin sensitivity. We conclude that prepartum BCS had minimal effect on systemic insulin sensitivity following parturition. The observed inconsistency between surrogate indices of insulin sensitivity and direct measurements of insulin and glucose tolerance adds support to growing concerns regarding their usefulness as tools to estimate systemic insulin action in periparturient cows.
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Affiliation(s)
- S Saed Samii
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV, USA
| | - J E Rico
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV, USA
- Department of Animal Science, Cornell University, Ithaca, NY, USA
| | - A T Mathews
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV, USA
| | - A N Davis
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV, USA
| | - C L Orndorff
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV, USA
| | - L O Aromeh
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV, USA
| | - J W McFadden
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV, USA
- Department of Animal Science, Cornell University, Ithaca, NY, USA
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Abstract
GH is one of the insulin counterregulatory hormones which acts in the opposite way to insulin, increasing the glucose production by the liver and kidneys and decreasing glucose uptake from peripheral tissues, thus being a hyperglycemic hormone. When in excess, as in acromegaly, it induces glucose intolerance and diabetes. As expected, patients with GH deficiency (GHD) have hypoglycemia, especially in early childhood, but as GH is also a lipolytic hormone, these patients are becoming obese with higher percentages of body fat. Although obesity in general is directly related to insulin resistance, in patients with GH secretion disorders this relationship may be altered. In acromegaly there is a decrease in fat mass with worsening insulin sensitivity and mice with isolated GHD are characterized by greater insulin sensitivity despite excess fat mass. In humans with GHD, body composition shows increased body fat and decreased free fat mass, but the results regarding insulin sensitivity are still controversial in these patients. These discrepant results regarding insulin sensitivity in patients with GHD suggest the existence of other variables influencing these results. In the present review, we will try to follow the path of the different researches conducted on this subject, both in animal and human models, with the goal of understanding the current knowledge of insulin sensitivity across the spectrum of GHD. Arch Endocrinol Metab. 2019;63(6):582-91.
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Affiliation(s)
- Heraldo Mendes Garmes
- Departamento de Clínica MédicaFaculdade de Ciências MédicasUniversidade Estadual de CampinasCampinasSPBrasil Divisão de Endocrinologia, Departamento de Clínica Médica, Faculdade de Ciências Médicas da Universidade Estadual de Campinas (FCM-Unicamp), Campinas, SP, Brasil
| | - Alejandro Rosell Castillo
- Departamento de Clínica MédicaFaculdade de Ciências MédicasUniversidade Estadual de CampinasCampinasSPBrasil Divisão de Endocrinologia, Departamento de Clínica Médica, Faculdade de Ciências Médicas da Universidade Estadual de Campinas (FCM-Unicamp), Campinas, SP, Brasil
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Zheng M, Yang T, Zhu C, Fu Y, Hsu YF. Arabidopsis GSM1 is involved in ABI4-regulated ABA signaling under high-glucose condition in early seedling growth. Plant Sci 2019; 287:110183. [PMID: 31481206 DOI: 10.1016/j.plantsci.2019.110183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 06/29/2019] [Accepted: 07/02/2019] [Indexed: 05/21/2023]
Abstract
In plants, sugar acts as an essential signaling molecule that modulates various aspects of metabolism, growth and development, which are also controlled by phytohormones. However, the molecular mechanism of cross-talk between sugar and phytohormones still remains to be elucidated. We have identified gsm1 (glucose-hypersensitive mutant 1) as a mutant with impaired cotyledon development that shows sensitivity to exogenous abscisic acid (ABA). The addition of fluridone can reverse the glucose (Glc) inhibitory effect in gsm1, implying that endogenous ABA is involved in the Glc response of gsm1. In 4.5% Glc, the expression of Glc-induced ABA-responsive genes in gsm1-1 was nearly two times higher than that in the wild type. Compared to gsm1-1, the gsm1-1 abi4-1 double mutant exhibited reduced sensitivity to Glc and ABA, which was similar to the Glc and ABA insensitive phenotype of abi4-1, suggesting that ABI4 is epistatic to GSM1. In the treatment with 4.5% Glc, the GSM1 transcript level was greatly increased in abi4-1 by almost 4-fold of that in the wild type. These data suggest that GSM1 plays an important role in the ABI4-regulated Glc-ABA signaling cascade during Arabidopsis early seedling growth.
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Affiliation(s)
- Min Zheng
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing 400715, China
| | - Tingting Yang
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing 400715, China
| | - Chunyan Zhu
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing 400715, China
| | - Yufan Fu
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing 400715, China
| | - Yi-Feng Hsu
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing 400715, China.
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Jiang Z, Zhou J, Li T, Tian M, Lu J, Jia Y, Wan G, Chen K. Hepatic deficiency of Poldip2 in type 2 diabetes dampens lipid and glucose homeostasis. Metabolism 2019; 99:90-101. [PMID: 31351995 DOI: 10.1016/j.metabol.2019.153948] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 07/05/2019] [Indexed: 01/14/2023]
Abstract
Moderate or low level hydrogen peroxides has been shown to play an important role in vascular smooth muscle cell (VSMC) function, in which the polymerase DNA-directed interacting protein 2 (Poldip2), functioned as a key regulator of NOX4 activity. In current study, we unexpectedly found that type 2 diabetes mellitus (T2DM) substantially suppresses the hepatic Poldip2 expression, and that the hepatic deficiency of Poldip2 may be correlated with dysregulation of hepatic cholesterol and plasma triglycerides. In cultured hepatocytes, we found that both insulin and leptin may inhibit hepatic expression of Poldip2 under high glucose concentration, but these suppressions were totally abolished under normoglycemic condition. POLDIP2 siRNA knockdown significantly impaired the H2O2 induction by insulin or leptin under normoglycemic condition, contributing the accumulation of cholesterol in cultured liver cells. The in vivo restoration of hepatic Poldip2 expression in T2DM mice remarkably rescued the moderate H2O2 generation in livers versus control mice, resulting in significant amelioration of hepatic cholesterol accumulation and plasma triglyceride levels. Importantly, the moderate induction of H2O2 in livers dramatically improved the hepatic PI3K-C1/AKT signaling or dampened PI3K-C2γ/AKT signaling through suppression of PTEN and PTP1B activities, thereby inhibiting the hepatic expression of HMGCR and SREBP2 for cholesterol synthesis. Moreover, the restitution of hepatic Poldip2 expression in diabetic mice significantly lowered the VLDL-cholesterol production rate, and substantially suppressed PEPCK and G6Pase expressions for gluconeogenesis, thus significantly improving the plasma insulin and glucose levels, and ITT and GTT outcomes in diabetic mice. Our findings suggest that hepatic dysregulation of Poldip2 may contribute to diabetic dyslipidemia and hyperglycemia.
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Affiliation(s)
- Zhengxuan Jiang
- Department of Ophthalmology, Second Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China
| | - Jielin Zhou
- Department of Nutrition and Food Science, Anhui Medical University School of Public Health, Hefei, Anhui, China
| | - Tao Li
- Department of Nutrition and Food Science, Anhui Medical University School of Public Health, Hefei, Anhui, China
| | - Mengjun Tian
- Department of Nutrition and Food Science, Anhui Medical University School of Public Health, Hefei, Anhui, China
| | - Jing Lu
- Department of Nutrition and Food Science, Anhui Medical University School of Public Health, Hefei, Anhui, China
| | - Yajing Jia
- Department of Nutrition and Food Science, Anhui Medical University School of Public Health, Hefei, Anhui, China
| | - Guangming Wan
- Department of Ophthalmology, First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan, China.
| | - Keyang Chen
- Department of Ophthalmology, Second Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China; Department of Nutrition and Food Science, Anhui Medical University School of Public Health, Hefei, Anhui, China.
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Chen S, Chen M, Wei W, Qiu L, Zhang L, Cao Q, Ying Z. Glucose Homeostasis following Diesel Exhaust Particulate Matter Exposure in a Lung Epithelial Cell-Specific IKK2-Deficient Mouse Model. Environ Health Perspect 2019; 127:57009. [PMID: 31095431 PMCID: PMC6791567 DOI: 10.1289/ehp4591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 04/25/2019] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Pulmonary inflammation is believed to be central to the pathogenesis due to exposure to fine particulate matter with aerodynamic diameter [Formula: see text] ([Formula: see text]). This central role, however, has not yet been systemically examined. OBJECTIVE In the present study, we exploited a lung epithelial cell-specific inhibitor [Formula: see text] kinase 2 (IKK2) knockout mouse model to determine the role of pulmonary inflammation in the pathophysiology due to exposure to diesel exhaust particulate matter (DEP). METHODS [Formula: see text] (lung epithelial cell-specific IKK2 knockout, KO) and [Formula: see text] (wild-type, tgWT) mice were intratracheally instilled with either vehicle or DEP for 4 months, and their inflammatory response and glucose homeostasis were then assessed. RESULTS In comparison with tgWT mice, lung epithelial cell-specific IKK2-deficient mice had fewer DEP exposure-induced bronchoalveolar lavage fluid immune cells and proinflammatory cytokines as well as fewer DEP exposure-induced circulating proinflammatory cytokines. Glucose and insulin tolerance tests revealed that lung epithelial cell-specific IKK2 deficiency resulted in markedly less DEP exposure-induced insulin resistance and greater glucose tolerance. Akt phosphorylation analyses of insulin-responsive tissues showed that DEP exposure primarily targeted hepatic insulin sensitivity. Lung epithelial cell-specific IKK2-deficient mice had significantly lower hepatic insulin resistance than tgWT mice had. Furthermore, this difference in insulin resistance was accompanied by consistent differences in hepatic insulin receptor substrate 1 serine phosphorylation and inflammatory marker expression. DISCUSSION Our findings suggest that in a tissue-specific knockout mouse model, an IKK2-dependent pulmonary inflammatory response was essential for the development of abnormal glucose homeostasis due to exposure to DEP. https://doi.org/10.1289/EHP4591.
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Affiliation(s)
- Sufang Chen
- Department of Geriatric Endocrinology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Department of Medicine Cardiology Division, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Minjie Chen
- Department of Medicine Cardiology Division, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Wei Wei
- Department of Medicine Cardiology Division, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Bile Pancreatic Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lianglin Qiu
- Department of Medicine Cardiology Division, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Occupational and Environmental Health, School of Public Health, Nantong University, Nantong, China
| | - Li Zhang
- Department of Medicine Cardiology Division, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Qi Cao
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Zhekang Ying
- Department of Medicine Cardiology Division, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Gumus D, Yoruk E, Kalayci-Yuksek F, Uz G, Topal-Sarikaya A, Ang-Kucuker M. The Effects of Insulin and Glucose on Different Characteristics of a UPEC: Alterations in Growth Rate and Expression Levels of some Virulence Genes. Clin Lab 2019; 63:1589-1597. [PMID: 29035446 DOI: 10.7754/clin.lab.2017.170313] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Host factors are known to modulate virulence, antibiotic susceptibility, and growth rate of bacteria. The effect of human insulin and glucose on growth rate and expression of virulence genes (usp, sfa/foc, cnf1) of a uropathogenic E. coli (UPEC) strain were investigated in this study. METHODS E. coli C7 was grown in tryptic soy broth (TSB-control) and TSB containing 20 µU/mL insulin, 200 µU/mL insulin, 0.1% glucose, and 200 µU/mL insulin + 0.1% glucose. Growth rates were determined via optical density measurement in a spectrophotometer. Real-time polymerase chain reaction was used to determine the gene expression levels. Statistical analyses were performed via Tukey's post hoc-test. RESULTS Differences were found to be not statistically significant for bacterial growth rate in TSB and TSB with insulin and/or glucose. The expression levels of all three virulence genes were shown to be reduced significantly in the presence of insulin and/or glucose. The highest degree of repression was observed in 200 µU/mL insulin added to TSB. Also, the repression level of the gene expression was revealed to be reduced in 0.1% glucose supplemented TSB. CONCLUSIONS In the present study, it was shown that insulin and glucose can modulate UPEC's gene expression while the growth rate was not affected.
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Sami F, Siddiqui H, Hayat S. Interaction of glucose and phytohormone signaling in plants. Plant Physiol Biochem 2019; 135:119-126. [PMID: 30529977 DOI: 10.1016/j.plaphy.2018.11.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/31/2018] [Accepted: 11/06/2018] [Indexed: 05/23/2023]
Abstract
Energy acts as a primary prerequisite for plant growth like all the other organisms. Soluble sugars function in providing enough supply of nutrients which further helps in building macromolecules and energy to carry out specific and coordinated development. Sugars functions as nutrient as well as signaling molecule to promote cell division and differentiation in plants. Intriguingly, glucose has emerged as a crucial signaling molecule where hexokinase1 acts as the conserved glucose sensor. On the molecular scale, an extensive crosstalk between glucose and phytohormone signaling has been observed where glucose signals trigger multiple hexokinase1-dependent as well as hexokinase1-independent pathways to mediate diverse developmental, physiological and molecular mechanisms. Taken together, these findings this review focused on the glucose crosstalk with several classical plant hormonal-signaling pathways and the crucial role of hexokinase1 in modulating plant physiological processes.
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Affiliation(s)
- Fareen Sami
- Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh, 202002, India
| | - Husna Siddiqui
- Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh, 202002, India
| | - Shamsul Hayat
- Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh, 202002, India.
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Joseph B, Shimojo G, Li Z, Thompson-Bonilla MDR, Shah R, Kanashiro A, Salgado HC, Ulloa L. Glucose Activates Vagal Control of Hyperglycemia and Inflammation in Fasted Mice. Sci Rep 2019; 9:1012. [PMID: 30700738 PMCID: PMC6354016 DOI: 10.1038/s41598-018-36298-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/14/2018] [Indexed: 11/18/2022] Open
Abstract
Sepsis is a leading cause of death in hospitalized patients. Many experimental treatments may have failed in clinical trials for sepsis, in part, because they focused on immune responses of healthy animals that did not mimic the metabolic settings of septic patients. Epidemiological studies show an association between metabolic and immune alterations and over 1/3 of septic patients are diabetic, but the mechanism linking these systems is unknown. Here, we report that metabolic fasting increased systemic inflammation and worsened survival in experimental sepsis. Feeding and administration of glucose in fasted mice activated the vagal tone without affecting blood pressure. Vagal stimulation attenuated hyperglycemia and serum TNF levels in sham but only hyperglycemia in splenectomized mice. Vagal stimulation induced the production of dopamine from the adrenal glands. Experimental diabetes increased hyperglycemia and systemic inflammation in experimental sepsis. Fenoldopam, a specific dopaminergic type-1 agonist, attenuated hyperglycemia and systemic inflammation in diabetic endotoxemic mice. These results indicate that glucose activates vagal control of hyperglycemia and inflammation in fasted septic mice via dopamine.
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Affiliation(s)
- Biju Joseph
- Department of Surgery, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Guilherme Shimojo
- Department of Surgery, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Zhifeng Li
- Department of Surgery, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Maria Del Rocio Thompson-Bonilla
- Department of Surgery, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA
- Hospital "October 1st", ISSSTE", 1669 National Polytechnic Institute Ave, Mexico City, Mexico
| | - Roshan Shah
- Department of Surgery, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Alexandre Kanashiro
- Department of Surgery, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA
- Department of Physiology, Medical School - University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Helio C Salgado
- Department of Physiology, Medical School - University of São Paulo, Ribeirão Preto, SP, 14049-900, Brazil
| | - Luis Ulloa
- Department of Surgery, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA.
- Center for Immunity and Inflammation, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA.
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13
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Saijun Z, Xin L, Jie W, Shumin X, Shuaihui L, Pei Y. Reduced β2GPI Inhibiting Glomerular Mesangial Cells VEGF-NO Axis Uncoupling Induced by High Glucose. Biomed Res Int 2018; 2018:5484731. [PMID: 30112400 PMCID: PMC6077591 DOI: 10.1155/2018/5484731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 06/19/2018] [Indexed: 11/30/2022]
Abstract
VEGF-NO axis uncoupling is an important pathogenesis for DN. Reduced β2GPI could play a part in VEGF signaling pathway and has a protective effect on diabetic vascular disease. This study investigates the effect of reduced β2GPI on glomerular mesangial cells VEGF-NO axis uncoupling induced by high glucose. Compared to control group, glomerular mesangial cell line HBZY-1 cells treated with high glucose expressed higher levels of VEGF mRNA and protein and produced more ROS but less NO. The related proteins related to VEGF-NO axis were assayed. High glucose could significantly increase the expression of the level of VEGFR2 and obviously increase phosphorylation of Akt and eNOS but significantly decrease the expression of GTP cyclohydrolase 1 (GCH-1), reducing the production of eNOS dimer. Both β2GPI and reduced β2GPI partly reverse these effects caused by high glucose. Reduced β2GPI had stronger effect than β2GPI. GCH-1 is the speed limit of tetrahydrobiopterin (BH4) synthesis enzyme. As the key part of eNOS cofactors, BH4 could partly restore eNOS dimer induced by high glucose. Our results indicated that high glucose could interfere with eNOS dimer formation. β2GPI and reduced β2GPI can partly reverse the VEGF-NO axis uncoupling by restoring the GCH-1 expression level and then promote eNOS dimer formation.
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Affiliation(s)
- Zhou Saijun
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tongan Road No. 66, the District of Heping, Tianjin 300070, China
| | - Li Xin
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tongan Road No. 66, the District of Heping, Tianjin 300070, China
| | - Wang Jie
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tongan Road No. 66, the District of Heping, Tianjin 300070, China
| | - Xiao Shumin
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tongan Road No. 66, the District of Heping, Tianjin 300070, China
| | - Liu Shuaihui
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tongan Road No. 66, the District of Heping, Tianjin 300070, China
| | - Yu Pei
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tongan Road No. 66, the District of Heping, Tianjin 300070, China
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14
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Mach F, Ray KK, Wiklund O, Corsini A, Catapano AL, Bruckert E, De Backer G, Hegele RA, Hovingh GK, Jacobson TA, Krauss RM, Laufs U, Leiter LA, März W, Nordestgaard BG, Raal FJ, Roden M, Santos RD, Stein EA, Stroes ES, Thompson PD, Tokgözoğlu L, Vladutiu GD, Gencer B, Stock JK, Ginsberg HN, Chapman MJ. Adverse effects of statin therapy: perception vs. the evidence - focus on glucose homeostasis, cognitive, renal and hepatic function, haemorrhagic stroke and cataract. Eur Heart J 2018; 39:2526-2539. [PMID: 29718253 PMCID: PMC6047411 DOI: 10.1093/eurheartj/ehy182] [Citation(s) in RCA: 209] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/09/2017] [Accepted: 03/22/2018] [Indexed: 12/17/2022] Open
Abstract
Aims To objectively appraise evidence for possible adverse effects of long-term statin therapy on glucose homeostasis, cognitive, renal and hepatic function, and risk for haemorrhagic stroke or cataract. Methods and results A literature search covering 2000-2017 was performed. The Panel critically appraised the data and agreed by consensus on the categorization of reported adverse effects. Randomized controlled trials (RCTs) and genetic studies show that statin therapy is associated with a modest increase in the risk of new-onset diabetes mellitus (about one per thousand patient-years), generally defined by laboratory findings (glycated haemoglobin ≥6.5); this risk is significantly higher in the metabolic syndrome or prediabetes. Statin treatment does not adversely affect cognitive function, even at very low levels of low-density lipoprotein cholesterol and is not associated with clinically significant deterioration of renal function, or development of cataract. Transient increases in liver enzymes occur in 0.5-2% of patients taking statins but are not clinically relevant; idiosyncratic liver injury due to statins is very rare and causality difficult to prove. The evidence base does not support an increased risk of haemorrhagic stroke in individuals without cerebrovascular disease; a small increase in risk was suggested by the Stroke Prevention by Aggressive Reduction of Cholesterol Levels study in subjects with prior stroke but has not been confirmed in the substantive evidence base of RCTs, cohort studies and case-control studies. Conclusion Long-term statin treatment is remarkably safe with a low risk of clinically relevant adverse effects as defined above; statin-associated muscle symptoms were discussed in a previous Consensus Statement. Importantly, the established cardiovascular benefits of statin therapy far outweigh the risk of adverse effects.
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Affiliation(s)
- François Mach
- Division of Cardiology, Department of Medical Specialties, Foundation for Medical Researches, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4 1205 Geneva, Switzerland
| | - Kausik K Ray
- Imperial Centre for Cardiovascular Disease Prevention, Department of Primary Care and Public Health, School of Public Health, Imperial College London, London, UK
| | - Olov Wiklund
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
- Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Alberto Corsini
- Department of Pharmacological and Biomolecular Sciences, University of Milan and IRCCS Multimedica, Milan, Italy
| | - Alberico L Catapano
- Department of Pharmacological and Biomolecular Sciences, University of Milan and IRCCS Multimedica, Milan, Italy
| | - Eric Bruckert
- National Institute for Health and Medical Research (INSERM) UMRS1166, Department of Endocrinology-Metabolism, ICAN—Institute of CardioMetabolism and Nutrition, AP-HP, Hôpital de la Pitié, Paris, France
| | - Guy De Backer
- Department of Public Health, University Hospital Ghent, Ghent, Belgium
| | - Robert A Hegele
- Department of Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - G Kees Hovingh
- Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | | | - Ronald M Krauss
- Department of Atherosclerosis Research, Children's Hospital Oakland Research Institute, Oakland, CA, USA
| | - Ulrich Laufs
- Department of Cardiology, University of Leipzig, Leipzig, Germany
| | - Lawrence A Leiter
- Li Ka Shing Knowledge Institute of St Michael's Hospital, University of Toronto, Toronto, ON, Canada
| | - Winfried März
- Vth Department of Medicine (Nephrology, Hypertensiology, Endocrinology, Diabetology, Rheumatology), Medical Faculty of Mannheim, University of Heidelberg, Mannheim, Germany
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University Graz, Graz, Austria
| | - Børge G Nordestgaard
- Department of Clinical Biochemistry and The Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- The Copenhagen City Heart Study, Frederiksberg Hospital, Copenhagen University Hospital, Copenhagen, Denmark
| | - Frederick J Raal
- Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa
| | - Michael Roden
- German Center for Diabetes Research (DZD), München-Neuherberg, Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- Department of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Raul D Santos
- Hospital Israelita Albert Einstein, São Paulo, Brazil
- Heart Institute (InCor), University of São Paulo Medical School Hospital, São Paulo, Brazil
| | - Evan A Stein
- Metabolic and Atherosclerosis Research Center, Cincinnati, OH, USA
| | - Erik S Stroes
- Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | | | - Lale Tokgözoğlu
- Department of Cardiology, Hacettepe University, Ankara, Turkey
| | - Georgirene D Vladutiu
- Jacobs School of Medicine & Biomedical Sciences, University at Buffalo, The State University of New York, New York, USA
| | - Baris Gencer
- Division of Cardiology, Department of Medical Specialties, Foundation for Medical Researches, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4 1205 Geneva, Switzerland
| | - Jane K Stock
- European Atherosclerosis Society, Gothenburg, Sweden
| | - Henry N Ginsberg
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, USA
| | - M John Chapman
- National Institute for Health and Medical Research (INSERM), and University of Pierre and Marie Curie—Paris 6, Pitié Salpêtrière, Paris, France
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15
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Petrussa E, Boscutti F, Vianello A, Casolo V. 'Last In-First Out': seasonal variations of non-structural carbohydrates, glucose-6-phosphate and ATP in tubers of two Arum species. Plant Biol (Stuttg) 2018; 20:346-356. [PMID: 29181866 DOI: 10.1111/plb.12673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
Knowledge on the metabolism of polysaccharide reserves in wild species is still scarce. In natural sites we collected tubers of Arum italicum Mill. and A. maculatum L. - two geophytes with different apparent phenological timing, ecology and chorology - during five stages of the annual cycle in order to understand patterns of reserve accumulation and degradation. Both the entire tuber and its proximal and distal to shoot portion were utilised. Pools of non-structural carbohydrates (glucose, sucrose and starch), glucose-6-phosphate and ATP were analysed as important markers of carbohydrate metabolism. In both species, starch and glucose content of the whole tuber significantly increased from sprouting to the maturation/senescence stages, whereas sucrose showed an opposite trend; ATP and glucose-6-phosphate were almost stable and dropped only at the end of the annual cycle. Considering the two different portions of the tuber, both ATP and glucose-6-phosphate concentrations were higher in proximity to the shoot in all seasonal stages, except the flowering stage. Our findings suggest that seasonal carbon partitioning in the underground organ is driven by phenology and occurs independently of seasonal climate conditions. Moreover, our results show that starch degradation, sustained by elevated ATP and glucose-6-phosphate pools, starts in the peripheral, proximal-to-shoot portion of the tuber, consuming starch accumulated in the previous season, as a 'Last In-First Out' mechanism of carbohydrate storage.
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Affiliation(s)
- E Petrussa
- Laboratory of Plant Biology, Department of Agricultural, Food, Animal and Environmental Sciences, University of Udine, Udine, Italy
| | - F Boscutti
- Laboratory of Plant Biology, Department of Agricultural, Food, Animal and Environmental Sciences, University of Udine, Udine, Italy
| | - A Vianello
- Laboratory of Plant Biology, Department of Agricultural, Food, Animal and Environmental Sciences, University of Udine, Udine, Italy
| | - V Casolo
- Laboratory of Plant Biology, Department of Agricultural, Food, Animal and Environmental Sciences, University of Udine, Udine, Italy
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16
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Tang DM, Qin SJ, Zhu ZT, Lyu DG. [Effects of exogenous glucose on growth and root nitrogen metabolism in Malus baccata]. Ying Yong Sheng Tai Xue Bao 2018; 29:797-804. [PMID: 29722221 DOI: 10.13287/j.1001-9332.201803.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
To examine the effects of external glucose on growth, root architecture and nitrogen metabolism of Malus baccata seedlings in low carbon soil condition, Malus baccata seedlings were grown in sandy soil with the concentration of soil organic matter being 0.65%. The experiment consisted of three treatments: Control, with 2 g·kg-1 glucose that equal to the ambient microbial biomass carbon (MBC), and with 10 g·kg-1 glucose that was five times higher than the ambient MBC. The plant height, biomass, total root length and superficial area of the five times MBC group were 12.3%, 26.4%, 23.2% and 14.6% higher than that of the control, respectively. Root diameter, root volume and average diameter exhibited no significant difference under glucose treatments. The root activity was significantly increased under equal and five times MBC-glucose treatments, and reached its peak at 3 d and 15 d, about 119.1% and 75.7% higher than the control, respectively. Exogenous glucose addition significantly enhanced the concentrations of NO3-, NO2- and NH4+ in roots. The activities of nitrate reductase, glutamine synthetase, glutamate dehydrogenase, glutamate synthase, glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase were substantially increased in the roots, especially under five times MBC treatment. Five times higher than the ambient MBC of external carbon source promoted biomass accumulation, root growth, morphogenesis and N absorption of plants in low carbon sandy soil.
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Affiliation(s)
- Dong Mei Tang
- College of Horticulture, Shenyang Agricultural University/Liaoning Province Key Laboratory of Fruit Quality Development and Regulation, Shenyang 110866, China
| | - Si Jun Qin
- College of Horticulture, Shenyang Agricultural University/Liaoning Province Key Laboratory of Fruit Quality Development and Regulation, Shenyang 110866, China
| | - Zi Tan Zhu
- College of Horticulture, Shenyang Agricultural University/Liaoning Province Key Laboratory of Fruit Quality Development and Regulation, Shenyang 110866, China
| | - De Guo Lyu
- College of Horticulture, Shenyang Agricultural University/Liaoning Province Key Laboratory of Fruit Quality Development and Regulation, Shenyang 110866, China
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17
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Sun P, Esquivel-Elizondo S, Zhao Y, Wu Y. Glucose triggers the cytotoxicity of Citrobacter sp. R1 against Microcystis aeruginosa. Sci Total Environ 2017; 603-604:18-25. [PMID: 28614737 DOI: 10.1016/j.scitotenv.2017.06.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/01/2017] [Accepted: 06/07/2017] [Indexed: 06/07/2023]
Abstract
Algicidal bacteria offer a promising option for killing Microcystis aeruginosa, one notorious cyanobacteria causing harmful algal blooms. In this study, Citrobacter sp. R1 presented high algicidal activity (81.6±2.2%, 72h) against M. aeruginosa when cultured using glucose, while it showed no algicidal activity (0±3.4%) when cultured using wheat bran, suggesting that appropriate carbon source is crucial for algicidal bacteria in killing M. aeruginosa. The underlying algicidal mechanism of strain R1 was explored by studying the effect of different carbon sources (glucose and wheat bran) on its key algicidal gene expression and total protein translation. While the glycogen synthase gene (glgA), cloned from strain R1 via transposon mutagenesis, was for the first time related to algicidal activity, its transcriptional level was not positively correlated with the algicidal activity of strain R1. We found that, the translation of total protein of strain R1 was relatively less when cultured with glucose, compared to growth with wheat bran. This indicated that the functional algicidal gene of strain R1 exerts its algicidal activity at protein translational level. These findings not only reveal the importance of appropriate carbon source for strain R1 for controlling M. aeruginosa, but also bring insights into its underlying algicidal mechanism.
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Affiliation(s)
- Pengfei Sun
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China; College of Life Sciences, Zhejiang University, 310058 Hangzhou, Zhejiang, PR China
| | - Sofia Esquivel-Elizondo
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 South McAllister Avenue, Tempe, AZ 85287-5701, USA
| | - Yuhua Zhao
- College of Life Sciences, Zhejiang University, 310058 Hangzhou, Zhejiang, PR China.
| | - Yonghong Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China; Biodesign Swette Center for Environmental Biotechnology, Arizona State University, 1001 South McAllister Avenue, Tempe, AZ 85287-5701, USA.
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18
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Abbasi NA, Akan OB. An Information Theoretical Analysis of Human Insulin-Glucose System Toward the Internet of Bio-Nano Things. IEEE Trans Nanobioscience 2017; 16:783-791. [PMID: 29028203 DOI: 10.1109/tnb.2017.2762160] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Molecular communication is an important tool to understand biological communications with many promising applications in Internet of Bio-Nano Things (IoBNT). The insulin-glucose system is of key significance among the major intra-body nanonetworks, since it fulfills metabolic requirements of the body. The study of biological networks from information and communication theoretical (ICT) perspective is necessary for their introduction in the IoBNT framework. Therefore, the objective of this paper is to provide and analyze for the first time in the literature, a simple molecular communication model of the human insulin-glucose system from ICT perspective. The data rate, channel capacity, and the group propagation delay are analyzed for a two-cell network between a pancreatic beta cell and a muscle cell that are connected through a capillary. The results point out a correlation between an increase in insulin resistance and a decrease in the data rate and channel capacity, an increase in the insulin transmission rate, and an increase in the propagation delay. We also propose applications for the introduction of the system in the IoBNT framework. Multi-cell insulin glucose system models may be based on this simple model to help in the investigation, diagnosis, and treatment of insulin resistance by means of novel IoBNT applications.
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Suyama S, Lei W, Kubota N, Kadowaki T, Yada T. Adiponectin at physiological level glucose-independently enhances inhibitory postsynaptic current onto NPY neurons in the hypothalamic arcuate nucleus. Neuropeptides 2017; 65:1-9. [PMID: 28606559 DOI: 10.1016/j.npep.2017.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/17/2017] [Accepted: 03/17/2017] [Indexed: 12/13/2022]
Abstract
Adiponectin regulates glucose and lipid metabolism, acting against atherosclerosis and metabolic syndrome. Accumulating evidences suggest that adiponectin acts on the brain including the arcuate nucleus of hypothalamus (ARC). The ARC contains orexigenic neuropeptide Y (NPY)/agouti related peptide (AgRP) neurons and anorexigenic proopiomelanocortin (POMC) neurons, the first order neurons for feeding regulation. We recently reported that intracerebroventricular injection of adiponectin at low glucose level suppressed food intake, while at elevated glucose level it promoted food intake, exhibiting glucose-dependent reciprocal effects. As an underlying neuronal mechanism, physiological level of adiponectin at low glucose activated ARC POMC neurons and at high glucose inactivated them. Now, whether physiological level of adiponectin also affects NPY/AgRP neurons is essential for fully understanding the adiponectin action, but it remains to be clarified. We here report that a physiological dose of adiponectin, in both high and low glucose conditions, attenuated action potential firing without altering resting membrane potential in ARC NPY neurons. This adiponectin effect was abolished by GABAA receptor blockade. Adiponectin enhanced amplitude but not frequency of inhibitory postsynaptic current (IPSC) onto NPY neurons. These results demonstrate that adiponectin enhances IPSC onto NPY neurons to attenuate action potential firing in NPY neurons in a glucose-independent manner, being contrasted to its glucose-dependent effect on POMC neurons.
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Affiliation(s)
- Shigetomo Suyama
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan
| | - Wang Lei
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan
| | - Naoto Kubota
- Department of Diabetes and Metabolic Diseases, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Takashi Kadowaki
- Department of Diabetes and Metabolic Diseases, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Toshihiko Yada
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 320-0498, Japan.
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20
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Brar GS, Barrow BM, Watson M, Griesbach R, Choung E, Welch A, Ruzsicska B, Raleigh DP, Zraika S. Neprilysin Is Required for Angiotensin-(1-7)'s Ability to Enhance Insulin Secretion via Its Proteolytic Activity to Generate Angiotensin-(1-2). Diabetes 2017; 66:2201-2212. [PMID: 28559246 PMCID: PMC5521860 DOI: 10.2337/db16-1318] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 05/17/2017] [Indexed: 12/13/2022]
Abstract
Recent work has renewed interest in therapies targeting the renin-angiotensin system (RAS) to improve β-cell function in type 2 diabetes. Studies show that generation of angiotensin-(1-7) by ACE2 and its binding to the Mas receptor (MasR) improves glucose homeostasis, partly by enhancing glucose-stimulated insulin secretion (GSIS). Thus, islet ACE2 upregulation is viewed as a desirable therapeutic goal. Here, we show that, although endogenous islet ACE2 expression is sparse, its inhibition abrogates angiotensin-(1-7)-mediated GSIS. However, a more widely expressed islet peptidase, neprilysin, degrades angiotensin-(1-7) into several peptides. In neprilysin-deficient mouse islets, angiotensin-(1-7) and neprilysin-derived degradation products angiotensin-(1-4), angiotensin-(5-7), and angiotensin-(3-4) failed to enhance GSIS. Conversely, angiotensin-(1-2) enhanced GSIS in both neprilysin-deficient and wild-type islets. Rather than mediating this effect via activation of the G-protein-coupled receptor (GPCR) MasR, angiotensin-(1-2) was found to signal via another GPCR, namely GPCR family C group 6 member A (GPRC6A). In conclusion, in islets, intact angiotensin-(1-7) is not the primary mediator of beneficial effects ascribed to the ACE2/angiotensin-(1-7)/MasR axis. Our findings warrant caution for the concurrent use of angiotensin-(1-7) compounds and neprilysin inhibitors as therapies for diabetes.
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Affiliation(s)
- Gurkirat S Brar
- Veterans Affairs Puget Sound Health Care System, Seattle, WA
| | | | - Matthew Watson
- Department of Chemistry, Stony Brook University, Stony Brook, NY
| | - Ryan Griesbach
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA
| | - Edwina Choung
- Veterans Affairs Puget Sound Health Care System, Seattle, WA
| | - Andrew Welch
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA
| | - Bela Ruzsicska
- Institute for Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, NY
| | - Sakeneh Zraika
- Veterans Affairs Puget Sound Health Care System, Seattle, WA
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, WA
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21
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Sun EW, de Fontgalland D, Rabbitt P, Hollington P, Sposato L, Due SL, Wattchow DA, Rayner CK, Deane AM, Young RL, Keating DJ. Mechanisms Controlling Glucose-Induced GLP-1 Secretion in Human Small Intestine. Diabetes 2017; 66:2144-2149. [PMID: 28385801 PMCID: PMC5860185 DOI: 10.2337/db17-0058] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/12/2017] [Indexed: 12/25/2022]
Abstract
Intestinal glucose stimulates secretion of the incretin hormone glucagon-like peptide 1 (GLP-1). The mechanisms underlying this pathway have not been fully investigated in humans. In this study, we showed that a 30-min intraduodenal glucose infusion activated half of all duodenal L cells in humans. This infusion was sufficient to increase plasma GLP-1 levels. With an ex vivo model using human gut tissue specimens, we showed a dose-responsive GLP-1 secretion in the ileum at ≥200 mmol/L glucose. In ex vivo tissue from the duodenum and ileum, but not the colon, 300 mmol/L glucose potently stimulated GLP-1 release. In the ileum, this response was independent of osmotic influences and required delivery of glucose via GLUT2 and mitochondrial metabolism. The requirement of voltage-gated Na+ and Ca2+ channel activation indicates that membrane depolarization occurs. KATP channels do not drive this, as tolbutamide did not trigger release. The sodium-glucose cotransporter 1 (SGLT1) substrate α-MG induced secretion, and the response was blocked by the SGLT1 inhibitor phlorizin or by replacement of extracellular Na+ with N-methyl-d-glucamine. This is the first report of the mechanisms underlying glucose-induced GLP-1 secretion from human small intestine. Our findings demonstrate a dominant role of SGLT1 in controlling glucose-stimulated GLP-1 release in human ileal L cells.
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Affiliation(s)
- Emily W Sun
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Dayan de Fontgalland
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Philippa Rabbitt
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Paul Hollington
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Luigi Sposato
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Steven L Due
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - David A Wattchow
- Discipline of Surgery, Flinders University, Adelaide, South Australia, Australia
| | - Christopher K Rayner
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Adam M Deane
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Intensive Care Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Richard L Young
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
- National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Damien J Keating
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
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Bouckenooghe T, Vandewalle B, Lukowiak B, Kerr-Conte J, Belaïch S, Gmyr V, Dubois M, Riachy R, Pattou F. Modulation of Specific Beta Cell Gene (Re)Expression during In Vitro Expansion of Human Pancreatic Islet Cells. Cell Transplant 2017; 12:799-807. [PMID: 14653626 DOI: 10.3727/000000003108747271] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The need for transplantable beta cells with a stable phenotype has given rise to several strategies including the expansion of existing pancreatic islets and/or growth of new ones. In vitro studies of beta cell proliferation on extracellular matrices plus growth factors have highlighted a possible cell expansion technique; however, the technique was accompanied with loss of insulin secretion. Herein we showed that human islet cell proliferation was marked by a decreased expression of specific differentiation markers, particularly insulin, insulin promoting factor-1 (IPF-1), and glucokinase. After a 6-day expansion period, we tried to reexpress the beta cell differentiation markers with compounds known for their differentiation and/or insulin-secreting properties. Sodium butyrate was a potent factor of IPF-1, insulin, and glucokinase gene reexpression; it also clearly induced secretion of gastrin, a known neogenic factor. Other compounds, namely TGF-β, calcitriol, GLP-1, and activin A, efficiently enhanced the glucose sensor machinery, particularly Glut-1 and glucokinase, thus triggering glucose responsiveness. Our results indicate that specific beta cell gene expression may be induced after expansion and dedifferentiation. This rekindles interest in human beta cell expansion. The possible stabilization of specialized genes needed by beta cells to fulfill their role as nutrient sensors and metabolic regulators may also be of interest to ensure graft maintenance and efficiency.
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Affiliation(s)
- Thomas Bouckenooghe
- Thérapie Cellulaire du Diabète, INSERM, ERIM 0106, Faculté de Médecine, Place de Verdun, 59045 Lille, France
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Gachon F, Loizides-Mangold U, Petrenko V, Dibner C. Glucose Homeostasis: Regulation by Peripheral Circadian Clocks in Rodents and Humans. Endocrinology 2017; 158:1074-1084. [PMID: 28324069 DOI: 10.1210/en.2017-00218] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 03/10/2017] [Indexed: 12/15/2022]
Abstract
Most organisms, including humans, have developed an intrinsic system of circadian oscillators, allowing the anticipation of events related to the rotation of Earth around its own axis. The mammalian circadian timing system orchestrates nearly all aspects of physiology and behavior. Together with systemic signals, emanating from the central clock that resides in the hypothalamus, peripheral oscillators orchestrate tissue-specific fluctuations in gene expression, protein synthesis, and posttranslational modifications, driving overt rhythms in physiology and behavior. There is increasing evidence on the essential roles of the peripheral oscillators, operative in metabolically active organs in the regulation of body glucose homeostasis. Here, we review some recent findings on the molecular and cellular makeup of the circadian timing system and its implications in the temporal coordination of metabolism in health and disease.
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Affiliation(s)
- Frédéric Gachon
- Department of Diabetes and Circadian Rhythms, Nestlé Institute of Health Sciences, CH-1015 Lausanne, Switzerland
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ursula Loizides-Mangold
- Division of Endocrinology, Diabetes, Hypertension and Nutrition, Department of Internal Medicine Specialties, University Hospital of Geneva, CH-1211 Geneva, Switzerland
- Department of Cell Physiology and Metabolism, Diabetes Center, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Volodymyr Petrenko
- Division of Endocrinology, Diabetes, Hypertension and Nutrition, Department of Internal Medicine Specialties, University Hospital of Geneva, CH-1211 Geneva, Switzerland
- Department of Cell Physiology and Metabolism, Diabetes Center, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Charna Dibner
- Division of Endocrinology, Diabetes, Hypertension and Nutrition, Department of Internal Medicine Specialties, University Hospital of Geneva, CH-1211 Geneva, Switzerland
- Department of Cell Physiology and Metabolism, Diabetes Center, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
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Dickerson MT, Vierra NC, Milian SC, Dadi PK, Jacobson DA. Osteopontin activates the diabetes-associated potassium channel TALK-1 in pancreatic β-cells. PLoS One 2017; 12:e0175069. [PMID: 28403169 PMCID: PMC5389796 DOI: 10.1371/journal.pone.0175069] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/20/2017] [Indexed: 12/17/2022] Open
Abstract
Glucose-stimulated insulin secretion (GSIS) relies on β-cell Ca2+ influx, which is modulated by the two-pore-domain K+ (K2P) channel, TALK-1. A gain-of-function polymorphism in KCNK16, the gene encoding TALK-1, increases risk for developing type-2 diabetes. While TALK-1 serves an important role in modulating GSIS, the regulatory mechanism(s) that control β-cell TALK-1 channels are unknown. Therefore, we employed a membrane-specific yeast two-hybrid (MYTH) assay to identify TALK-1-interacting proteins in human islets, which will assist in determining signaling modalities that modulate TALK-1 function. Twenty-one proteins from a human islet cDNA library interacted with TALK-1. Some of these interactions increased TALK-1 activity, including intracellular osteopontin (iOPN). Intracellular OPN is highly expressed in β-cells and is upregulated under pre-diabetic conditions to help maintain normal β-cell function; however, the functional role of iOPN in β-cells is poorly understood. We found that iOPN colocalized with TALK-1 in pancreatic sections and coimmunoprecipitated with human islet TALK-1 channels. As human β-cells express two K+ channel-forming variants of TALK-1, regulation of these TALK-1 variants by iOPN was assessed. At physiological voltages iOPN activated TALK-1 transcript variant 3 channels but not TALK-1 transcript variant 2 channels. Activation of TALK-1 channels by iOPN also hyperpolarized resting membrane potential (Vm) in HEK293 cells and in primary mouse β-cells. Intracellular OPN was also knocked down in β-cells to test its effect on β-cell TALK-1 channel activity. Reducing β-cell iOPN significantly decreased TALK-1 K+ currents and increased glucose-stimulated Ca2+ influx. Importantly, iOPN did not affect the function of other K2P channels or alter Ca2+ influx into TALK-1 deficient β-cells. These results reveal the first protein interactions with the TALK-1 channel and found that an interaction with iOPN increased β-cell TALK-1 K+ currents. The TALK-1/iOPN complex caused Vm hyperpolarization and reduced β-cell glucose-stimulated Ca2+ influx, which is predicted to inhibit GSIS.
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Affiliation(s)
- Matthew T. Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Nicholas C. Vierra
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Sarah C. Milian
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Prasanna K. Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
| | - David A. Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States of America
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McIsaac W, Ferguson AV. Glucose concentrations modulate brain-derived neurotrophic factor responsiveness of neurones in the paraventricular nucleus of the hypothalamus. J Neuroendocrinol 2017; 29. [PMID: 28258626 DOI: 10.1111/jne.12464] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/07/2017] [Accepted: 02/20/2017] [Indexed: 11/30/2022]
Abstract
The hypothalamic paraventricular nucleus (PVN) is critical for normal energy balance and has been shown to contain high levels of both brain-derived neurotrophic factor (BDNF) and tropomyosin-receptor kinase B mRNA. Microinjections of BDNF into the PVN increase energy expenditure, suggesting that BDNF plays an important role in energy homeostasis through direct actions in this nucleus. The present study aimed to examine the postsynaptic effects of BDNF on the membrane potential of PVN neurones, and also to determine whether extracellular glucose concentrations modulated these effects. We used hypothalamic PVN slices from male Sprague-Dawley rats to perform whole cell current-clamp recordings from PVN neurones. BDNF was bath applied at a concentration of 2 nmol L-1 and the effects on membrane potential determined. BDNF caused depolarisations in 54% of neurones (n=25; mean±SEM, 8.9±1.2 mV) and hyperpolarisations in 23% (n=11; -6.7±1.4 mV), whereas the remaining cells were unaffected. These effects were maintained in the presence of tetrodotoxin (n=9; 56% depolarised, 22% hyperpolarised, 22% nonresponders), or the GABAa antagonist bicuculline (n=12; 42% depolarised, 17% hyperpolarised, 41% nonresponders), supporting the conclusion that these effects on membrane potential were postsynaptic. Current-clamp recordings from PVN neurones next examined the effects of BDNF on these neurones at varying extracellular glucose concentrations. Larger proportions of PVN neurones hyperpolarised in response to BDNF as the glucose concentrations decreased [10 mmol L-1 glucose 23% (n=11) of neurones hyperpolarised, whereas, at 0.2 mmol L-1 glucose, 71% showed hyperpolarising effects (n=12)]. Our findings reveal that BDNF has direct GABAA independent effects on PVN neurones, which are modulated by local glucose concentrations. The latter observation further emphasises the critical importance of using physiologically relevant conditions in an investigation of the central pathways involved in the regulation of energy homeostasis.
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Affiliation(s)
- W McIsaac
- Centre for Neuroscience, Queens University, Kingston, ON, Canada
| | - A V Ferguson
- Centre for Neuroscience, Queens University, Kingston, ON, Canada
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26
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Lara-Núñez A, García-Ayala BB, Garza-Aguilar SM, Flores-Sánchez J, Sánchez-Camargo VA, Bravo-Alberto CE, Vázquez-Santana S, Vázquez-Ramos JM. Glucose and sucrose differentially modify cell proliferation in maize during germination. Plant Physiol Biochem 2017; 113:20-31. [PMID: 28157579 DOI: 10.1016/j.plaphy.2017.01.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 12/19/2016] [Accepted: 01/20/2017] [Indexed: 05/21/2023]
Abstract
Glucose and sucrose play a dual role: as carbon and energy sources and as signaling molecules. In order to address the impact that sugars may have on maize seeds during germination, embryo axes were incubated with or without either of the two sugars. Expression of key cell cycle markers and protein abundance, cell patterning and de novo DNA synthesis in root meristem zones were analyzed. Embryo axes without added sugars in imbibition medium were unable to grow after 7 days; in sucrose, embryo axes developed seminal and primary roots with numerous root hairs, whereas in glucose axes showed a twisted morphology, no root hair formation but callus-like structures on adventitious and primary seminal roots. More and smaller cells were observed with glucose treatment in root apical meristems. de novo DNA synthesis was stimulated more by glucose than by sucrose. At 24 h of imbibition, expression of ZmCycD2;2a and ZmCycD4;2 was increased by sucrose and reduced by glucose. CDKA1;1 and CDKA2;1 expression was stimulated equally by both sugars. Protein abundance patterns were modified by sugars: ZmCycD2 showed peaks on glucose at 12 and 36 h of imbibition whereas sucrose promoted ZmCycD3 protein accumulation. In presence of glucose ZmCycD3, ZmCycD4 and ZmCycD6 protein abundance was reduced after 24 h. Finally, both sugars stimulated ZmCDKA protein accumulation but at different times. Overall, even though glucose appears to act as a stronger mitogen stimulator, sucrose stimulated the expression of more cell cycle markers during germination. This work provides evidence of a differential response of cell cycle markers to sucrose and glucose during maize germination that may affect the developmental program during plantlet establishment.
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Affiliation(s)
- Aurora Lara-Núñez
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Brendy B García-Ayala
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Sara M Garza-Aguilar
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Jesús Flores-Sánchez
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Victor A Sánchez-Camargo
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Carlos E Bravo-Alberto
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Sonia Vázquez-Santana
- Facultad de Ciencias, Departamento de Biología Comparada, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Jorge M Vázquez-Ramos
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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Eliakim A. Endocrinology and Pediatric Exercise Science-2016. Pediatr Exerc Sci 2017; 29:45-48. [PMID: 28271805 DOI: 10.1123/pes.2017-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Pediatric Exercise Science Year That Was section aims to highlight the most important (to the author's opinion) manuscripts that were published in 2016 in the field of endocrinology and pediatric exercise science. This year's selection includes studies showing that 1) Induction of T4 to T3 conversion by type 2 deiodinase following aerobic exercise in skeletal muscles was associated with concomitant increase in peroxisome proliferatoractivated receptor-γ coactivator-1α, and mitochondrial oxidative capacity and therefore plays an important mechanistic role in the muscle adaptation to exercise training. 2) Hypothyroidism in fetal and early postnatal life was associated with impaired spatial learning and memory and with reduced hippocampal brain-derived neurotrophic factor in male and female rat pups. Forced (treadmill) and voluntary (wheel) exercise alleviated all these biochemical and neuro-cognitive deficits. 3) The relationship between different exercise intensities and carbohydrate requirements to maintain euglycemia at basal insulin levels among adolescent and young adults with Type 1 diabetes are nonlinear but rather inverted- U with no exogenous glucose required to maintain stable glucose level at high-intensity exercise (80%). The implication of these studies to the pediatric population, their importance and the new research avenues that were opened by these studies is emphasized.
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28
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Holland WL, Xia JY, Johnson JA, Sun K, Pearson MJ, Sharma AX, Quittner-Strom E, Tippetts TS, Gordillo R, Scherer PE. Inducible overexpression of adiponectin receptors highlight the roles of adiponectin-induced ceramidase signaling in lipid and glucose homeostasis. Mol Metab 2017; 6:267-275. [PMID: 28271033 PMCID: PMC5323887 DOI: 10.1016/j.molmet.2017.01.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 12/27/2016] [Accepted: 01/05/2017] [Indexed: 02/06/2023] Open
Abstract
Objective Adiponectin and the signaling induced by its cognate receptors, AdipoR1 and AdipoR2, have garnered attention for their ability to promote insulin sensitivity and oppose steatosis. Activation of these receptors promotes the deacylation of ceramide, a lipid metabolite that appears to play a causal role in impairing insulin signaling. Methods Here, we have developed transgenic mice that overexpress AdipoR1 or AdipoR2 under the inducible control of a tetracycline response element. These represent the first inducible genetic models that acutely manipulate adiponectin receptor signaling in adult mouse tissues, which allows us to directly assess AdipoR signaling on glucose and lipid metabolism. Results Overexpression of either adiponectin receptor isoform in the adipocyte or hepatocyte is sufficient to enhance ceramidase activity, whole body glucose metabolism, and hepatic insulin sensitivity, while opposing hepatic steatosis. Importantly, metabolic improvements fail to occur in an adiponectin knockout background. When challenged with a leptin-deficient genetic model of type 2 diabetes, AdipoR2 expression in adipose or liver is sufficient to reverse hyperglycemia and glucose intolerance. Conclusion These observations reveal that adiponectin is critical for AdipoR-induced ceramidase activation which enhances hepatic glucose and lipid metabolism via rapidly acting “cross-talk” between liver and adipose tissue sphingolipids. Adiponectin receptor signaling in adipose prompts beneficial effects on whole-body glucose and lipid metabolism. The small molecule adiponectin receptor antagonist AdipoRon lowers hepatic ceramides. Depletion of ceramides in adipocytes results in diminished hepatic ceramide accumulation. Depletion of ceramides in hepatocytes results in diminished adipose sphingolipid accumulation. Adiponectin is essential for the beneficial effects of adiponectin receptors on glucose, ceramide, and lipid metabolism.
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Affiliation(s)
- William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA.
| | - Jonathan Y Xia
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Joshua A Johnson
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Kai Sun
- Center for Metabolic and Degenerative Diseases, Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Mackenzie J Pearson
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Ankit X Sharma
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Ezekiel Quittner-Strom
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Trevor S Tippetts
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Ruth Gordillo
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
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29
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Kakei M, Yoshida M, Dezaki K, Ito K, Yamada H, Funazaki S, Kawakami M, Sugawara H, Yada T. Glucose and GTP-binding protein-coupled receptor cooperatively regulate transient receptor potential-channels to stimulate insulin secretion [Review]. Endocr J 2016; 63:867-876. [PMID: 27321586 DOI: 10.1507/endocrj.ej16-0262] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In pancreatic β-cells, glucose-induced closure of the ATP-sensitive K+ (KATP) channel is an initial process triggering glucose-stimulated insulin secretion (GSIS). This KATP-channel dependent pathway has been believed to be a central mechanism for GSIS. However, since the resting membrane potential of cells is determined by the balance of the net result of current amplitudes in outward and inward directions, it must be taken into consideration that not only KATP channel inhibition but also inward current via the basal opening of non-selective cation channels (NSCCs) plays a crucial role in membrane potential regulation. The basal activity of NSCCs is essential to effectively evoke depolarization in concert with KATP channel closure that is dependent on glucose metabolism. The present study summarizes recent findings regarding the roles of NSCCs in GSIS and GTP-binding protein coupled receptor-(GPCR) operated potentiation of GSIS.
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Affiliation(s)
- Masafumi Kakei
- Internal Medicine, Saitama Medical Center, Jichi Medical University, Saitama 330-8503, Japan
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30
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Wang W, Wang WH, Azadzoi KM, Dai P, Wang Q, Sun JB, Zhang WT, Shu Y, Yang JH, Yan Z. Alu RNA accumulation in hyperglycemia augments oxidative stress and impairs eNOS and SOD2 expression in endothelial cells. Mol Cell Endocrinol 2016; 426:91-100. [PMID: 26891959 DOI: 10.1016/j.mce.2016.02.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/04/2016] [Accepted: 02/11/2016] [Indexed: 11/16/2022]
Abstract
Endothelial dysfunction resulting from oxidative stress and inflammation plays a dominant role in hyperglycemia-induced vasculopathy. While double-stranded RNA (dsRNA) accumulates in redox and inflammatory conditions, its precise role in hyperglycemia-associated endothelial dysfunction remains unclear. This study aimed to investigate whether and how endogenous dsRNA contributes to endothelial dysfunction via oxidative stress. We used a dsRNA-specific antibody J2 to detect and immunoprecipitate cellular dsRNA. Acquired dsRNA was recognized by cDNA library construction and DNA sequencing. Quantitative PCR, ELISA and immunoassays were performed to identify changes induced by acquired dsRNA in primary human umbilical vein endothelial cells (HUVEC). Our data showed that endogenous dsRNA homologous to Alu Sc subfamily accumulated in hyperglycemic HUVEC. Comparing Alu-transfected HUVEC with high-glucose treated HUVEC, we found that Alu RNA elicited the production of reactive oxygen species (ROS) and up-regulated interleukin-1β (IL-1β) expression and secretion in a similar manner as high-glucose treatment. Moreover, Alu RNA impeded the expression of endothelial nitric oxide synthase (eNOS) and superoxide dismutase 2 (SOD2), increased ROS production and activated nuclear factor NFκB by chemically scavenging ROS and inactivation of NFκB. The repressed expression of eNOS and SOD2 resulted from Alu RNA-mediated negative regulatory mechanisms. Our study uncovered endogenous Alu RNA accumulation in hyperglycemic endothelial cells that provoked endothelial oxidative stress and dysfunction by suppressing SOD2 and eNOS expression at both transcription and translation levels via NFκB signaling pathway. These findings suggest a novel regulatory mechanism that involves endogenous dsRNA in endothelial oxidative stress and dysfunction.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Wei-Hua Wang
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Kazem M Azadzoi
- Departments of Urology and Surgery, VA Boston Healthcare System, Boston University School of Medicine, Boston 510660, MA, USA
| | - Peng Dai
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Qin Wang
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Jian-Bin Sun
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Wen-Tao Zhang
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Yi Shu
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Jing-Hua Yang
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China; Departments of Urology and Surgery, VA Boston Healthcare System, Boston University School of Medicine, Boston 510660, MA, USA.
| | - Zhen Yan
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
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Zhou F, Huo J, Liu Y, Liu H, Liu G, Chen Y, Chen B. Elevated glucose levels impair the WNT/β-catenin pathway via the activation of the hexosamine biosynthesis pathway in endometrial cancer. J Steroid Biochem Mol Biol 2016; 159:19-25. [PMID: 26923859 DOI: 10.1016/j.jsbmb.2016.02.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 01/04/2016] [Accepted: 02/18/2016] [Indexed: 12/12/2022]
Abstract
Endometrial cancer (EC) is one of the most common gynecological malignancies in the world. Associations between fasting glucose levels (greater than 5.6mmol/L) and the risk of cancer fatality have been reported. However, the underlying link between glucose metabolic disease and EC remains unclear. In the present study, we explored the influence of elevated glucose levels on the WNT/β-catenin pathway in EC. Previous studies have suggested that elevated concentrations of glucose can drive the hexosamine biosynthesis pathway (HBP) flux, thereby enhancing the O-GlcNAc modification of proteins. Here, we cultured EC cell lines, AN3CA and HEC-1-B, with various concentrations of glucose. Results showed that when treated with high levels of glucose, both lines showed increased expression of β-catenin and O-GlcNAcylation levels; however, these effects could be abolished by the HBP inhibitors, Azaserine and 6-Diazo-5-oxo-l-norleucine, and be restored by glucosamine. Moreover the AN3CA and HEC-1-B cells that were cultured with or without PUGNAc, an inhibitor of the O-GlcNAcase, showed that PUGNAc increased β-catenin levels. The results suggest that elevated glucose levels increase β-catenin expression via the activation of the HBP in EC cells. Subcellular fractionation experiments showed that AN3CA cells had a higher expression of intranuclear β-catenin in high glucose medium. Furthermore, TOP/FOP-Flash and RT-PCR results showed that glucose-induced increased expression of β-catenin triggered the transcription of target genes. In conclusion, elevated glucose levels, via HBP, increase the O-GlcNAcylation level, thereby inducing the over expression of β-catenin and subsequent transcription of the target genes in EC cells.
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Affiliation(s)
- Fuxing Zhou
- Department of Gynecology and Obstetrics, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Junwei Huo
- Department of Gynecology and Obstetrics, The First Hospital of Yulin, Yulin, Shaanxi 718000, China
| | - Yu Liu
- Department of Gynecology and Obstetrics, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Haixia Liu
- Department of Gynecology and Obstetrics, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Gaowei Liu
- Department of Gynecology and Obstetrics, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Ying Chen
- Department of Natural Medicine, School of Pharmacy, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Biliang Chen
- Department of Gynecology and Obstetrics, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
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Abstract
The incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are secreted from enteroendocrine cells in the intestine along with other gut hormones (PYY, CCK and neurotensin) shown to affect metabolism and/or appetite. The secretion of many gut hormones is highly increased after gastric bypass operations, which have turned out to be an effective therapy of not only obesity but also type 2 diabetes. These effects are likely to be due, at least in part, to increases in the secretion of these gut hormones (except GIP). Therefore, stimulation of the endogenous hormone represents an appealing therapeutic strategy, which has spurred an interest in understanding the regulation of gut hormone secretion and a search for particularly GLP-1 and PYY secretagogues. The secretion of the gut hormones is stimulated by oral intake of nutrients often including carbohydrate, protein and lipid. This review focuses on stimulators of gut hormone secretion, the mechanisms involved, and in particular models used to investigate secretion. A major break-through in this field was the development of methods to identify and isolate specific hormone producing cells, which allow detailed mapping of the expression profiles of these cells, whereas they are less suitable for physiological studies of secretion. Isolated perfused preparations of mouse and rat intestines have proven to be reliable models for dynamic hormone secretion and should be able to bridge the gap between the molecular details derived from the single cells to the integrated patterns observed in the intact animals.
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Affiliation(s)
- Berit Svendsen
- Department of Biomedical Sciences, Faculty of health Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of health Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
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Abstract
Glucose metabolism is subjected to diurnal variation, which might be mediated by alterations in the transcription pattern of clock genes and regulated by hormonal factors, as has been demonstrated for insulin. However, whether also glucagon is involved in the diurnal variation of glucose homeostasis is not known. We therefore examined glucagon secretion after meal ingestion (meal tolerance test) and during hypoglycemia (hyperinsulinemic hypoglycemic clamp at 2.5mmol/L glucose) and in vitro from isolated islets at ZT3 versus ZT15 in normal C57BL/6J mice and, furthermore, glucose levels and the insulin response to meal ingestion were also examined at these time points in glucagon receptor knockout mice (GCGR-/-) and their wildtype (wt) littermates. We found in normal mice that whereas the glucagon response to meal ingestion was not different between ZT3 and ZT15, the glucagon response to hypoglycemia was lower at ZT3 than at ZT15 and glucagon secretion from isolated islets was higher at ZT3 than at ZT15. GCGR-/- mice displayed lower basal glucose, a lower insulin response to meal and a higher insulin sensitivity than wt mice at ZT3 but not at ZT15. We conclude that there is a time dependent variation in glucagon secretion in normal mice, which is dependent both on intraislet and extraislet regulatory mechanisms and that the phenotype characteristics of a lower glucose and reduced insulin response to meal in GCGR-/- mice are evident only during the light phase. These findings suggest that glucagon signaling is a plausible contributor to the diurnal variation in glucose homeostasis which may explain that the phenotype of the GCGR-/- mice is dependent on the time of the day when it is examined.
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Affiliation(s)
- Siri Malmgren
- Department of Clinical Sciences in Lund, Section of Medicine, Lund University, Lund, Sweden
| | - Bo Ahrén
- Department of Clinical Sciences in Lund, Section of Medicine, Lund University, Lund, Sweden.
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Mrschtik M, O'Prey J, Lao LY, Long JS, Beaumatin F, Strachan D, O'Prey M, Skommer J, Ryan KM. DRAM-3 modulates autophagy and promotes cell survival in the absence of glucose. Cell Death Differ 2015; 22:1714-26. [PMID: 25929859 PMCID: PMC4563785 DOI: 10.1038/cdd.2015.26] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 02/15/2015] [Accepted: 02/16/2015] [Indexed: 12/27/2022] Open
Abstract
Macroautophagy is a membrane-trafficking process that delivers cytoplasmic constituents to lysosomes for degradation. The process operates under basal conditions as a mechanism to turnover damaged or misfolded proteins and organelles. As a result, it has a major role in preserving cellular integrity and viability. In addition to this basal function, macroautophagy can also be modulated in response to various forms of cellular stress, and the rate and cargoes of macroautophagy can be tailored to facilitate appropriate cellular responses in particular situations. The macroautophagy machinery is regulated by a group of evolutionarily conserved autophagy-related (ATG) proteins and by several other autophagy regulators, which either have tissue-restricted expression or operate in specific contexts. We report here the characterization of a novel autophagy regulator that we have termed DRAM-3 due to its significant homology to damage-regulated autophagy modulator (DRAM-1). DRAM-3 is expressed in a broad spectrum of normal tissues and tumor cells, but different from DRAM-1, DRAM-3 is not induced by p53 or DNA-damaging agents. Immunofluorescence studies revealed that DRAM-3 localizes to lysosomes/autolysosomes, endosomes and the plasma membrane, but not the endoplasmic reticulum, phagophores, autophagosomes or Golgi, indicating significant overlap with DRAM-1 localization and with organelles associated with macroautophagy. In this regard, we further proceed to show that DRAM-3 expression causes accumulation of autophagosomes under basal conditions and enhances autophagic flux. Reciprocally, CRISPR/Cas9-mediated disruption of DRAM-3 impairs autophagic flux confirming that DRAM-3 is a modulator of macroautophagy. As macroautophagy can be cytoprotective under starvation conditions, we also tested whether DRAM-3 could promote survival on nutrient deprivation. This revealed that DRAM-3 can repress cell death and promote long-term clonogenic survival of cells grown in the absence of glucose. Interestingly, however, this effect is macroautophagy-independent. In summary, these findings constitute the primary characterization of DRAM-3 as a modulator of both macroautophagy and cell survival under starvation conditions.
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Affiliation(s)
- M Mrschtik
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - J O'Prey
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - L Y Lao
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - J S Long
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - F Beaumatin
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - D Strachan
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - M O'Prey
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - J Skommer
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - K M Ryan
- Tumour Cell Death Laboratory, Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
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Guo S, Yao Q, Ke Z, Chen H, Wu J, Liu C. Resveratrol attenuates high glucose-induced oxidative stress and cardiomyocyte apoptosis through AMPK. Mol Cell Endocrinol 2015; 412:85-94. [PMID: 26054749 DOI: 10.1016/j.mce.2015.05.034] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND Diabetic cardiomyopathy (DCM) suggests a direct cellular insult to myocardium. Hyperglycemia-induced oxidative stress and apoptosis have been implicated in the pathogenesis of DCM. NADPH oxidase is a major source of reactive oxygen species (ROS) generation in cardiomyocytes. Resveratrol, a naturally occurring polyphenol, has shown beneficial effects on some cardiovascular complications associated with diabetes. OBJECTIVES We aimed to examine the role of resveratrol on high glucose-induced NADPH oxidase-derived ROS production and cardiac apoptosis, together with modulation of protein signaling pathways in cardiomyocytes. METHODS Primary cultures of neonatal rat cardiomyocytes were exposed to 30 mmol/L high glucose with or without resveratrol. Cell viability, apoptosis, superoxide formation, NADPH oxidase activity and its subunits expression, antioxidant enzymes activities, as well as the potential regulatory molecules AMPK, Akt and GSK-3β were assessed in cardiac cells. RESULTS Elevated ROS production induced by 30 mmol/L high glucose was inhibited with the addition of resveratrol in primary cultured neonatal rat cardiomyocytes. Consistently, resveratrol markedly suppressed the increased activity of NADPH oxidase and Rac1, as well as the enhanced expression of p67(phox), p47(phox), and gp91(phox) induced by high glucose. Lipid peroxidation, SOD, catalase, GSH-px activity and GSH content was reversed in the presence of resveratrol. Moreover, the expression of pro-apoptotic protein Bax was down regulated while anti-apoptotic protein Bcl-2 was up regulated. And cardiac cell injury and apoptosis were markedly rescued by resveratrol. In addition, resveratrol significantly increased phosphorylation of AMP-activated protein kinase (AMPK) at Thr172 in cardiomyocytes exposed to high glucose. Compound C, the pharmacologic inhibitor of AMPK, could mostly abrogate roles of resveratrol on cardiomyocytes in high glucose. In contrast, Akt and GSK-3β were little influenced by resveratrol. CONCLUSIONS Our data demonstrated that resveratrol protected cardiomyocytes against high glucose-induced apoptosis through suppression NADPH oxidase-derived ROS generation and maintenance endogenous antioxidant defenses. And the protective effects of resveratrol are mostly mediated by AMPK related pathway.
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Affiliation(s)
- Shuang Guo
- Hubei Province Key Laboratory on Cardiovascular, Cerebrovascular, and Metabolic Disorders, Hubei University of Science and Technology, Xianning, China
| | - Qing Yao
- Hubei Province Key Laboratory on Cardiovascular, Cerebrovascular, and Metabolic Disorders, Hubei University of Science and Technology, Xianning, China
| | - Zhiqiang Ke
- Hubei Province Key Laboratory on Cardiovascular, Cerebrovascular, and Metabolic Disorders, Hubei University of Science and Technology, Xianning, China
| | - Hongguang Chen
- Hubei Province Key Laboratory on Cardiovascular, Cerebrovascular, and Metabolic Disorders, Hubei University of Science and Technology, Xianning, China
| | - Jiliang Wu
- Hubei Province Key Laboratory on Cardiovascular, Cerebrovascular, and Metabolic Disorders, Hubei University of Science and Technology, Xianning, China.
| | - Chao Liu
- Hubei Province Key Laboratory on Cardiovascular, Cerebrovascular, and Metabolic Disorders, Hubei University of Science and Technology, Xianning, China.
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Meng Z, Wang Y, Lin Y, Nan S, Xu W, Hu B, Shen E. [MicroRNA-182 modulates high glucose-induced cardiomyocyte hypertrophy via targeting Rac1]. Zhonghua Xin Xue Guan Bing Za Zhi 2015; 43:619-624. [PMID: 26420324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To investigate the role and signalling of microRNA(miR)-182 on regulating high glucose-induced cardiomyocyte hypertrophy. METHODS The candidates of miR which might potentially be involved on targeting Rac1 were predicted by applying bioinformatics analysis. The expression of all related candidates miRs was verified by real-time reverse transcription-PCR (RT-PCR) in cardiac tissues of db/db mice and db/m mice. Then the relationship between candidates miR and Rac1 was investigated with Pearson relevant analysis. Neonatal mice cardiomyocytes were cultured and divided into 2 groups: normal glucose group and high glucose group. The level of selected miR and Rac1 in two groups was detected by RT-PCR. Neonatal mice cardiomyocytes were then randomly divided into 4 groups: normal glucose group, selected microRNA mimics control group, high glucose group, high glucose plus selected miR mimics control group. The morphology of cardiomyocyte in each group was detected under light microscope. Furthermore, Rac1, β-MHC and α-SMA expressions were detected in cultured cardiomyocyte treated by high glucose for 48 h after transfecting selected miR mimics by RT-PCR and Western blot. RESULTS A total of 6 miR candidates potentially targeting Rac1 were screened by bioinformatics, which were miR-182, miR-142-3p, miR-140, miR-101a, miR-429 and miR-200b. Among these candidates, miR-182 and miR-142-3p expression was significantly downregulated in cardiac tissues of db/db mice compared with db/m controls (P < 0.05). MiR-182 was negatively correlated with Rac1 by person analysis (r = -0.891 02). Downregulation of miR-182 and upregulation of Rac1, β-MHC, α-SMA were found in high glucose-induced cardiomyocyte. After transfection of miR-182 mimics, hypertrophic changes were significantly reduced and Rac1 as well β-MHC expression was significantly downregulated in cardiomyocyte incubated with high glucose. CONCLUSION MiR-182 might be involved in the regulation of high glucose-induced myocardial hypertrophy process via targeting Rac1.
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Affiliation(s)
- Zheying Meng
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, China
| | - Yu Wang
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, China
| | - Yanduan Lin
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, China
| | - Shuliang Nan
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, China
| | - Weiping Xu
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, China
| | - Bing Hu
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, China
| | - E Shen
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai 200233, China;
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Abstract
Diabetes and osteoporosis are both common diseases with increasing prevalences in the aging population. There is increasing evidence corroborating an association between diabetes mellitus and bone. This review will discuss the disease complications of diabetes on the skeleton, highlighting findings from epidemiological, molecular, and imaging studies in animal models and humans. Compared to control subjects, decreased bone mineral density (BMD) has been observed in type 1 diabetes mellitus, while on average, higher BMD has been found in type 2 diabetes; nonetheless, patients with both types of diabetes are seemingly at increased risk of fractures. Conventional diagnostics such as DXA measurements and the current fracture risk assessment tool (FRAX) risk prediction algorithm for estimating risk of osteoporotic fractures are not sufficient in the case of diabetes. A deterioration in bone microarchitecture and an inefficient distribution of bone mass with insufficiency of repair and adaptation mechanisms appear to be factors of relevance. A highly complex and heterogeneous molecular pathophysiology underlies diabetes-related bone disease, involving hormonal, immune, and perhaps genetic pathways. The detrimental effects of chronically elevated glucose levels on bone should be added to the more well-known complications of diabetes.
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Affiliation(s)
- Ling Oei
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- Netherlands Genomics Initiative (NGI)-sponsored Netherlands Consortium for Healthy Aging (NCHA), Rotterdam, The Netherlands
- Department of Internal Medicine, IJsselland Hospital, Capelle aan den IJssel, The Netherlands
| | - Fernando Rivadeneira
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- Netherlands Genomics Initiative (NGI)-sponsored Netherlands Consortium for Healthy Aging (NCHA), Rotterdam, The Netherlands
| | - M. Carola Zillikens
- Department of Internal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- Netherlands Genomics Initiative (NGI)-sponsored Netherlands Consortium for Healthy Aging (NCHA), Rotterdam, The Netherlands
| | - Edwin H. G. Oei
- Department of Radiology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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Yu H, Yang J, Xiao Q, Lü Y, Zhou X, Xia L, Nie D. Regulation of high glucose-mediated mucin expression by matrix metalloproteinase-9 in human airway epithelial cells. Exp Cell Res 2015; 333:127-35. [PMID: 25704757 DOI: 10.1016/j.yexcr.2015.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 02/02/2015] [Accepted: 02/10/2015] [Indexed: 11/15/2022]
Abstract
Mucus hypersecretion is the key manifestation in patients with chronic inflammatory airway diseases and mucin 5AC (MUC5AC) is a major component of airway mucus. Matrix metalloproteinases (MMP)-9, have been found to be involved in the pathogenesis of inflammatory airway diseases. Hyperglycemia has been shown to be an independent risk factor for respiratory infections. We hypothesize that high glucose (HG)-regulates MMP-9 production and MMP-9 activity through nicotinamide adenine dinucleotide phosphate (NADPH)/reactive oxygen species (ROS) cascades pathways, leading to mucin production in human airway epithelial cells (16HBE). We show that HG increases MMP-9 production, MMP-9 activity and MUC5AC expression. These effects are prevented by small interfering RNA (siRNA) for MMP-9, indicating that HG-induced mucin production is MMP-9-dependent. HG activates MMP-9 production, MMP-9 activity and MUC5AC overproduction, which is inhibited by nPG, DMSO and DPI (inhibitors of ROS and NADPH), suggesting that HG-activated mucin synthesis is mediated by NADPH/ROS in 16HBE cells. These observations demonstrate an important role for MMP-9 activated by NADPH/ROS signaling pathways in regulating HG-induced MUC5AC expression. These findings may bring new insights into the molecular pathogenesis of the infections related to diabetes mellitus and lead to novel therapeutic intervention for mucin overproduction in chronic inflammatory airway diseases.
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Affiliation(s)
- Hongmei Yu
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China.
| | - Juan Yang
- Division of Respiratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qian Xiao
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China
| | - Yang Lü
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China
| | - Xiangdong Zhou
- Division of Respiratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Li Xia
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China
| | - Daijing Nie
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuzhong District, Chongqing 400016, China
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He T, Guan X, Wang S, Xiao T, Yang K, Xu X, Wang J, Zhao J. Resveratrol prevents high glucose-induced epithelial-mesenchymal transition in renal tubular epithelial cells by inhibiting NADPH oxidase/ROS/ERK pathway. Mol Cell Endocrinol 2015; 402:13-20. [PMID: 25540919 DOI: 10.1016/j.mce.2014.12.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 12/11/2014] [Accepted: 12/11/2014] [Indexed: 11/28/2022]
Abstract
Resveratrol (RSV) is reported to have renoprotective activity against diabetic nephropathy, while the mechanisms underlying its function have not been fully elucidated. In this study, we investigate the effect and related mechanism of RSV against high glucose-induced epithelial to mesenchymal transition (EMT) in human tubular epithelial cells (HK-2). A typical EMT is induced by high glucose in HK-2 cells, accompanied by increased levels of reactive oxygen species (ROS). RSV exhibits a strong ability to inhibit high glucose-induced EMT by decreasing intracellular ROS levels via down-regulation of NADPH oxidase subunits NOX1 and NOX4. The activation of extracellular signal-regulated kinase (ERK1/2) is found to be involved in high glucose-induced EMT in HK-2 cells. RSV, like NADPH oxidase inhibitor diphenyleneiodonium, can block ERK1/2 activation induced by high glucose. Our results demonstrate that RSV is a potent agent against high glucose-induced EMT in renal tubular cells via inhibition of NADPH oxidase/ROS/ERK1/2 pathway.
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Affiliation(s)
- Ting He
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Xu Guan
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Song Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury of PLA, Third Military Medical University, Chongqing 400038, China
| | - Tangli Xiao
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Ke Yang
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Xinli Xu
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Junping Wang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury of PLA, Third Military Medical University, Chongqing 400038, China
| | - Jinghong Zhao
- Department of Nephrology, Institute of Nephrology of Chongqing and Kidney Center of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
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Abstract
MicroRNAs (miRNAs) have been implicated in a variety of physiological processes, however, the function of miRNAs in insulin secretion and type 2 diabetes is still unclear. Stxbp1 plays an essential role in exocytosis, and is crucial for insulin secretion. In this study, we focused on the molecular mechanism of Stxbp1 in insulin secretion by identifying its upstream regulators: miR-218 and miR-322. The expression of Stxbp1 was significantly increased in isolated mouse islets exposed to high levels of glucose within 1 h; while two of its predicted upstream miRNAs were found to be downregulated. Further study found that miR-218 and miR-322 directly interact with Stxbp1 by targeting the 3'UTR of its mRNA. MIN6 cells overexpressing the two miRNAs showed a sharp decline in insulin secretion and a decreased sensitivity to glucose; while the inhibition of the two miRNAs promoted insulin secretion. However, islets treated with prolonged high levels of glucose, which is known as glucolipotoxicity, displayed relatively high expression of miR-218 and miR-322, and a reduced level of expression of Stxbp1 accompanied by the blocking of insulin secretion. In summary, this study identified a pathway consisting of miR-218/322 and Stxbp1 in insulin secretion, contributing to a network of β-cell function involving miRNA.
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Affiliation(s)
- Hongmei Lang
- Departments of EndocrinologyBlood TransfusionChengdu Military General Hospital, Rongdu Road 270, Chengdu, Sichuan 610083, China
| | - Zhihua Ai
- Departments of EndocrinologyBlood TransfusionChengdu Military General Hospital, Rongdu Road 270, Chengdu, Sichuan 610083, China
| | - Zhiqing You
- Departments of EndocrinologyBlood TransfusionChengdu Military General Hospital, Rongdu Road 270, Chengdu, Sichuan 610083, China
| | - Yong Wan
- Departments of EndocrinologyBlood TransfusionChengdu Military General Hospital, Rongdu Road 270, Chengdu, Sichuan 610083, China
| | - Wei Guo
- Departments of EndocrinologyBlood TransfusionChengdu Military General Hospital, Rongdu Road 270, Chengdu, Sichuan 610083, China
| | - Jie Xiao
- Departments of EndocrinologyBlood TransfusionChengdu Military General Hospital, Rongdu Road 270, Chengdu, Sichuan 610083, China
| | - Xiaolan Jin
- Departments of EndocrinologyBlood TransfusionChengdu Military General Hospital, Rongdu Road 270, Chengdu, Sichuan 610083, China williamsjin@sinacom
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Venturelli OS, Zuleta I, Murray RM, El-Samad H. Population diversification in a yeast metabolic program promotes anticipation of environmental shifts. PLoS Biol 2015; 13:e1002042. [PMID: 25626086 PMCID: PMC4307983 DOI: 10.1371/journal.pbio.1002042] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 12/03/2014] [Indexed: 01/28/2023] Open
Abstract
Detailed study of the dynamic response of yeast to combinations of sugars reveals an anticipatory population diversification strategy that allows rapid adaptation to shifts in environmental carbon source availability. To survive in resource-limited and dynamic environments, microbial populations implement a diverse repertoire of regulatory strategies. These strategies often rely on anticipating impending environmental shifts, enabling the population to be prepared for a future change in conditions. It has long been known that cells optimize nutritional value from mixtures of carbon sources, for example glucose and galactose, by sequential activation of regulatory programs that allow for metabolizing the preferred carbon source first before metabolizing the secondary carbon source. Using automated flow-cytometry, we mapped the dynamical behavior of populations simultaneously presented with a large panel of different glucose and galactose concentrations. We show that, counter to expectations, in populations presented with glucose and galactose simultaneously, the galactose regulatory pathway is activated in a fraction of the cell population hours before glucose is fully consumed. We demonstrate that the size of this fraction of cells is tuned by the concentration of the two sugars. This population diversification may constitute a tradeoff between the benefit of rapid galactose consumption once glucose is depleted and the cost of expressing the galactose pathway. Delineating the strategies by which cells contend with combinatorial changing environments is crucial for understanding cellular regulatory organization. When presented with two carbon sources, microorganisms first consume the carbon substrate that supports the highest growth rate (e.g., glucose) and then switch to the secondary carbon source (e.g., galactose), a paradigm known as the Monod model. Sequential sugar utilization has been attributed to transcriptional repression of the secondary metabolic pathway, followed by activation of this pathway upon depletion of the preferred carbon source. In this work, we demonstrate that although Saccharomyces cerevisiae cells consume glucose before galactose, the galactose regulatory pathway is activated in a fraction of the cell population hours before glucose is fully consumed. This early activation reduces the time required for the population to transition between the two metabolic programs and provides a fitness advantage that might be crucial in competitive environments.
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Affiliation(s)
- Ophelia S. Venturelli
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- The California Institute for Quantitative Biosciences, University of California San Francisco, San Francisco, California, United States of America
| | - Ignacio Zuleta
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- The California Institute for Quantitative Biosciences, University of California San Francisco, San Francisco, California, United States of America
| | - Richard M. Murray
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Hana El-Samad
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- The California Institute for Quantitative Biosciences, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Wang HT, Yao CH, Ai JN, Cao XP, Xue S, Wang WL. Identification of carbohydrates as the major carbon sink of the marine microalga Isochrysis zhangjiangensis (Haptophyta) and optimization of its productivity by nitrogen manipulation. Bioresour Technol 2014; 171:298-304. [PMID: 25216035 DOI: 10.1016/j.biortech.2014.08.090] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 08/16/2014] [Accepted: 08/21/2014] [Indexed: 06/03/2023]
Abstract
Microalgae represent a potential feedstock for biofuel production. During cultivation under nitrogen-depleted conditions, carbohydrates, rather than neutral lipids, were the major carbon sink of the marine microalga Isochrysis zhangjiangensis (Haptophyta). Carbohydrates reached maximum levels of 21.2 pg cell(-1) on day 5, which was an increase of more than 7-fold from day 1, while neutral lipids simultaneously increased 1.9-fold from 4.0 to 7.6 pg cell(-1) during the ten-day nitrogen-depleted cultivation. The carbohydrate productivity of I. zhangjiangensis was improved by optimization of the nitrate supply mode. The maximum carbohydrate concentration was 0.95 g L(-1) under batch cultivation, with an initial nitrogen concentration of 31.0 mg L(-1), which was 2.4-fold greater than that achieved under nitrogen-depleted conditions. High performance liquid chromatography (HPLC) analysis showed that the accumulated carbohydrate in I. zhangjiangensis was composed of glucose. These results show that I. zhangjiangensis represents an ideal carbohydrate-enriched bioresource for biofuel production.
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Affiliation(s)
- Hai-Tao Wang
- Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chang-Hong Yao
- Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Jiang-Ning Ai
- Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xu-Peng Cao
- Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Song Xue
- Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Wei-liang Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
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Mishiro K, Imai T, Sugitani S, Kitashoji A, Suzuki Y, Takagi T, Chen H, Oumi Y, Tsuruma K, Shimazawa M, Hara H. Diabetes mellitus aggravates hemorrhagic transformation after ischemic stroke via mitochondrial defects leading to endothelial apoptosis. PLoS One 2014; 9:e103818. [PMID: 25133692 PMCID: PMC4136737 DOI: 10.1371/journal.pone.0103818] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 07/04/2014] [Indexed: 12/26/2022] Open
Abstract
Diabetes is a crucial risk factor for stroke and is associated with increased frequency and poor prognosis. Although endothelial dysfunction is a known contributor of stroke, the underlying mechanisms have not been elucidated. The aim of this study was to elucidate the mechanism by which chronic hyperglycemia may contribute to the worsened prognosis following stroke, especially focusing on mitochondrial alterations. We examined the effect of hyperglycemia on hemorrhagic transformation at 24 hours after middle cerebral artery occlusion (MCAO) in streptozotocin (STZ) -induced diabetic mice. We also examined the effects of high-glucose exposure for 6 days on cell death, mitochondrial functions and morphology in human brain microvascular endothelial cells (HBMVECs) or human endothelial cells derived from induced pluripotent stem cells (iCell endothelial cells). Hyperglycemia aggravated hemorrhagic transformation, but not infarction following stroke. High-glucose exposure increased apoptosis, capase-3 activity, and release of apoptosis inducing factor (AIF) and cytochrome c in HBMVECs as well as affected mitochondrial functions (decreased cell proliferation, ATP contents, mitochondrial membrane potential, and increased matrix metalloproteinase (MMP)-9 activity, but not reactive oxygen species production). Furthermore, morphological aberration of mitochondria was observed in diabetic cells (a great deal of fragmentation, vacuolation, and cristae disruption). A similar phenomena were seen also in iCell endothelial cells. In conclusion, chronic hyperglycemia aggravated hemorrhagic transformation after stroke through mitochondrial dysfunction and morphological alteration, partially via MMP-9 activation, leading to caspase-dependent apoptosis of endothelial cells of diabetic mice. Mitochondria-targeting therapy may be a clinically innovative therapeutic strategy for diabetic complications in the future.
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Affiliation(s)
- Keisuke Mishiro
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Takahiko Imai
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Sou Sugitani
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Akira Kitashoji
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Yukiya Suzuki
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Toshinori Takagi
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
- Departments of Neurosurgery, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Huayue Chen
- Department of Anatomy, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Yasunori Oumi
- Division of Instrument Analysis, Life Science Research Center, Gifu University, Gifu, Japan
| | - Kazuhiro Tsuruma
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
- * E-mail:
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Huang JS, Chuang CT, Liu MH, Lin SH, Guh JY, Chuang LY. Klotho attenuates high glucose-induced fibronectin and cell hypertrophy via the ERK1/2-p38 kinase signaling pathway in renal interstitial fibroblasts. Mol Cell Endocrinol 2014; 390:45-53. [PMID: 24721634 DOI: 10.1016/j.mce.2014.04.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 03/12/2014] [Accepted: 04/01/2014] [Indexed: 12/19/2022]
Abstract
Although exogenous klotho attenuates renal fibrosis, it is not known if exogenous klotho attenuates diabetic nephropathy (DN). Thus, we studied the anti-fibrotic mechanisms of klotho in terms of transforming growth factor-β (TGF-β) and signaling pathways in high glucose (HG, 30 mM)-cultured renal interstitial fibroblast (NRK-49F) cells. We found that HG increased klotho mRNA and protein expression. HG also activated TGF-β Smad2/3 signaling and activated extracellular signal-regulated kinase (ERK1/2) and p38 kinase signaling. Exogenous klotho (400 pM) attenuated HG-induced TGF-β bioactivity, type II TGF-β receptor (TGF-βRII) protein expression and TGF-β Smad2/3 signaling. Klotho also attenuated HG-activated ERK1/2 and p38 kinase. Additionally, klotho and inhibitors of ERK1/2 or p38 kinase attenuated HG-induced fibronectin and cell hypertrophy. Finally, renal tubular expression of klotho decreased in the streptozotin-diabetic rats at 8 weeks. Thus, exogenous klotho attenuates HG-induced profibrotic genes, TGF-β signaling and cell hypertrophy in NRK-49F cells. Moreover, klotho attenuates HG-induced fibronectin expression and cell hypertrophy via the ERK1/2 and p38 kinase-dependent pathways.
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Affiliation(s)
- Jau-Shyang Huang
- Department of Biological Science and Technology, Chung Hwa University of Medical Technology, Tainan, Taiwan
| | - Chao-Tang Chuang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Mei-Hsin Liu
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Sheng-Hsuan Lin
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jinn-Yuh Guh
- Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Department of Internal Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
| | - Lea-Yea Chuang
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
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Abstract
The link between chronic psychosocial and metabolic stress and the pathogenesis of disease has been extensively documented. Nevertheless, the cellular mechanisms by which stressful life experiences and their associated primary neuroendocrine mediators cause biological damage and increase disease risk remain poorly understood. The allostatic load model of chronic stress focuses on glucocorticoid dysregulation. In this Perspectives, we expand upon the metabolic aspects of this model-particularly glucose imbalance-and propose that mitochondrial dysfunction constitutes an early, modifiable target of chronic stress and stress-related health behaviours. Central to this process is mitochondrial regulation of energy metabolism and cellular signalling. Chronically elevated glucose levels damage both mitochondria and mitochondrial DNA, generating toxic products that can promote systemic inflammation, alter gene expression and hasten cell ageing. Consequently, the concept of 'mitochondrial allostatic load' defines the deleterious structural and functional changes that mitochondria undergo in response to elevated glucose levels and stress-related pathophysiology.
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Affiliation(s)
- Martin Picard
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia and the University of Pennsylvania, 3501 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Robert-Paul Juster
- Integrated Program in Neuroscience, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Bruce S McEwen
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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Diaz HL, Karnati SKR, Lyons MA, Dehority BA, Firkins JL. Chemotaxis toward carbohydrates and peptides by mixed ruminal protozoa when fed, fasted, or incubated with polyunsaturated fatty acids. J Dairy Sci 2014; 97:2231-43. [PMID: 24534499 DOI: 10.3168/jds.2013-7428] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 11/25/2013] [Indexed: 12/16/2023]
Abstract
In contrast to the well-characterized chemotaxis and migratory behavior between the dorsal and ventral locations of the rumen by isotrichids, we hypothesized that chemotaxis toward soluble nutrients maintains entodiniomorphid protozoa in the particulate fraction. The objectives of these experiments were to compare the dose-responsive chemotaxis (1) toward different glucose concentrations when ruminal samples were harvested from fed versus fasted cows; (2) toward increasing concentrations of glucose compared with xylose when protozoa were harvested from a fed cow; (3) toward peptides of bacterial, protozoal, and soy origin; and (4) toward glucose when mixed ruminal protozoa were previously incubated for 0, 3, or 6h in the presence of emulsified polyunsaturated fatty acids (PUFA; Liposyn II, Hospira, Lake Forest, IL). In experiment 1, isotrichid protozoa decreased chemotaxis toward increasing glucose concentration when cows were fasted. Entodiniomorphids exhibited chemotaxis to similar concentrations of glucose as did isotrichids, but to a lesser magnitude of response. In experiment 2, xylose was chemotactic to both groups. Xylose might draw fibrolytic entodiniomorphid protozoa toward newly ingested feed. In contrast, even though isotrichids should not use xylose as an energy source, they were highly chemoattracted to xylose. In experiment 3, entodiniomorphids were not selectively chemoattracted toward bacterial or protozoal peptides compared with soy peptides. In experiment 4, despite isotrichid populations decreasing in abundance with increasing time of incubation in PUFA, chemotaxis to glucose remained unchanged. In contrast, entodiniomorphids recovered chemotaxis to glucose with increased time of PUFA incubation. Current results support isotrichid chemotaxis to sugars but also our hypothesis that a more moderate chemotaxis toward glucose and peptides explains how they swim in the fluid but pass from the rumen with the potentially digestible fraction of particulates.
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Affiliation(s)
- H L Diaz
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - S K R Karnati
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - M A Lyons
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - B A Dehority
- Department of Animal Sciences, The Ohio State University, Columbus 43210
| | - J L Firkins
- Department of Animal Sciences, The Ohio State University, Columbus 43210.
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Bernsmeier C, Meyer-Gerspach AC, Blaser LS, Jeker L, Steinert RE, Heim MH, Beglinger C. Glucose-induced glucagon-like Peptide 1 secretion is deficient in patients with non-alcoholic fatty liver disease. PLoS One 2014; 9:e87488. [PMID: 24489924 PMCID: PMC3906180 DOI: 10.1371/journal.pone.0087488] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 12/26/2013] [Indexed: 02/06/2023] Open
Abstract
Background & Aims The incretins glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are gastrointestinal peptide hormones regulating postprandial insulin release from pancreatic β-cells. GLP-1 agonism is a treatment strategy in Type 2 diabetes and is evaluated in Non-alcoholic fatty liver disease (NAFLD). However, the role of incretins in its pathophysiology is insufficiently understood. Studies in mice suggest improvement of hepatic steatosis by GLP-1 agonism. We determined the secretion of incretins after oral glucose administration in non-diabetic NAFLD patients. Methods N = 52 patients (n = 16 NAFLD and n = 36 Non-alcoholic steatohepatitis (NASH) patients) and n = 50 matched healthy controls were included. Standardized oral glucose tolerance test was performed. Glucose, insulin, glucagon, GLP-1 and GIP plasma levels were measured sequentially for 120 minutes after glucose administration. Results Glucose induced GLP-1 secretion was significantly decreased in patients compared to controls (p<0.001). In contrast, GIP secretion was unchanged. There was no difference in GLP-1 and GIP secretion between NAFLD and NASH subgroups. All patients were insulin resistant, however HOMA2-IR was highest in the NASH subgroup. Fasting and glucose-induced insulin secretion was higher in NAFLD and NASH compared to controls, while the glucose lowering effect was diminished. Concomitantly, fasting glucagon secretion was significantly elevated in NAFLD and NASH. Conclusions Glucose-induced GLP-1 secretion is deficient in patients with NAFLD and NASH. GIP secretion is contrarily preserved. Insulin resistance, with hyperinsulinemia and hyperglucagonemia, is present in all patients, and is more severe in NASH compared to NAFLD. These pathophysiologic findings endorse the current evaluation of GLP-1 agonism for the treatment of NAFLD.
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Affiliation(s)
- Christine Bernsmeier
- Division of Gastroenterology and Hepatology, University Hospital Basel, Basel, Switzerland
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- * E-mail:
| | | | - Lea S. Blaser
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Lia Jeker
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Robert E. Steinert
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Markus H. Heim
- Division of Gastroenterology and Hepatology, University Hospital Basel, Basel, Switzerland
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Christoph Beglinger
- Division of Gastroenterology and Hepatology, University Hospital Basel, Basel, Switzerland
- Department of Biomedicine, University Hospital Basel, Basel, Switzerland
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Xiao F, Zimpelmann J, Agaybi S, Gurley SB, Puente L, Burns KD. Characterization of angiotensin-converting enzyme 2 ectodomain shedding from mouse proximal tubular cells. PLoS One 2014; 9:e85958. [PMID: 24454948 PMCID: PMC3893316 DOI: 10.1371/journal.pone.0085958] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 12/02/2013] [Indexed: 01/15/2023] Open
Abstract
Angiotensin-converting enzyme 2 (ACE2) is highly expressed in the kidney proximal tubule, where it cleaves angiotensin (Ang) II to Ang-(1-7). Urinary ACE2 levels increase in diabetes, suggesting that ACE2 may be shed from tubular cells. The aim of this study was to determine if ACE2 is shed from proximal tubular cells, to characterize ACE2 fragments, and to study pathways for shedding. Studies involved primary cultures of mouse proximal tubular cells, with ACE2 activity measured using a synthetic substrate, and analysis of ACE2 fragments by immunoblots and mass spectrometry. The culture media from mouse proximal tubular cells demonstrated a time-dependent increase in ACE2 activity, suggesting constitutive ACE2 shedding. ACE2 was detected in media as two bands at ∼90 kDa and ∼70 kDa on immunoblots. By contrast, full-length ACE2 appeared at ∼100 kDa in cell lysates or mouse kidney cortex. Mass spectrometry of the two deglycosylated fragments identified peptides matching mouse ACE2 at positions 18-706 and 18-577, respectively. The C-terminus of the 18-706 peptide fragment contained a non-tryptic site, suggesting that Met706 is a candidate ACE2 cleavage site. Incubation of cells in high D-glucose (25 mM) (and to a lesser extent Ang II) for 48–72 h increased ACE2 activity in the media (p<0.001), an effect blocked by inhibition of a disintegrin and metalloproteinase (ADAM)17. High D-glucose increased ADAM17 activity in cell lysates (p<0.05). These data indicate that two glycosylated ACE2 fragments are constitutively shed from mouse proximal tubular cells. ACE2 shedding is stimulated by high D-glucose, at least partly via an ADAM17-mediated pathway. The results suggest that proximal tubular shedding of ACE2 may increase in diabetes, which could enhance degradation of Ang II in the tubular lumen, and increase levels of Ang-(1-7).
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Affiliation(s)
- Fengxia Xiao
- Division of Nephrology, Department of Medicine, Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Joseph Zimpelmann
- Division of Nephrology, Department of Medicine, Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Samih Agaybi
- Division of Nephrology, Department of Medicine, Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Susan B. Gurley
- Division of Nephrology, Department of Medicine, Duke University Medical Centre, Durham, North Carolina, United States of America
| | - Lawrence Puente
- Sprott Center for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Kevin D. Burns
- Division of Nephrology, Department of Medicine, Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
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Afrazi S, Esmaeili-Mahani S, Sheibani V, Abbasnejad M. Neurosteroid allopregnanolone attenuates high glucose-induced apoptosis and prevents experimental diabetic neuropathic pain: in vitro and in vivo studies. J Steroid Biochem Mol Biol 2014; 139:98-103. [PMID: 24176764 DOI: 10.1016/j.jsbmb.2013.10.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 10/14/2013] [Accepted: 10/17/2013] [Indexed: 01/23/2023]
Abstract
Hyperglycemia plays a critical role in the development of diabetic neuropathy. Hyperglycemia induces oxidative stress in neurons, resulting in neuronal cell apoptosis and dysfunction. Anti-apoptotic properties of neurosteroids have been demonstrated in numerous cellular models of neurodegenerative studies. Here, the protective effects of neurosteroid allopregnanolone were investigated in in vitro and in vivo models of diabetic neuropathy. The data show that glucose decreased the viability of PC12 cells in a concentration-dependent manner. Allopregnanolone at concentrations of 2.5, 5 and 10μM markedly prevented high glucose-induced toxicity in naïve and NGF-treated (neuron-like) PC12 cells. Furthermore, treatment of diabetic rats with allopregnanolone (5 and 20mg/kg) significantly ameliorated diabetic-induced thermal hyperalgesia. Moreover, this neurosteroid inhibited caspase 3 and decreased Bax/Bcl2 ratio in high glucose-treated cells and spinal cord of diabetic rats. In conclusion, the data revealed that allopregnanolone has protective effects against hyperglycemic-induced cellular damage and prevention of cell apoptosis is involved in its mechanisms. Our findings suggest that allopregnanolone has protective effect against pro-apoptotic challenges such as diabetes and hyperglycemia and propose therapeutic potential of neurosteroids in attenuation of diabetic side effects such as neuropathy.
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Affiliation(s)
- Samira Afrazi
- Laboratory of Molecular Neuroscience, Kerman Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran; Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran
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Kooptiwut S, Mahawong P, Hanchang W, Semprasert N, Kaewin S, Limjindaporn T, Yenchitsomanus PT. Estrogen reduces endoplasmic reticulum stress to protect against glucotoxicity induced-pancreatic β-cell death. J Steroid Biochem Mol Biol 2014; 139:25-32. [PMID: 24120916 DOI: 10.1016/j.jsbmb.2013.09.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 09/27/2013] [Accepted: 09/30/2013] [Indexed: 02/07/2023]
Abstract
Estrogen can improve glucose homeostasis not only in diabetic rodents but also in humans. However, the molecular mechanism by which estrogen prevents pancreatic β-cell death remains unclear. To investigate this issue, INS-1 cells, a rat insulinoma cell line, were cultured in medium with either 11.1mM or 40mM glucose in the presence or the absence of estrogen. Estrogen significantly reduced apoptotic β-cell death by decreasing nitrogen-induced oxidative stress and the expression of the ER stress markers GRP 78, ATF6, P-PERK, PERK, uXBP1, sXBP1, and CHOP in INS-1 cells after prolonged culture in medium with 40mM glucose. In contrast, estrogen increased the expression of survival proteins, including sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA-2), Bcl-2, and P-p38, in INS-1 cells after prolonged culture in medium with 40mM glucose. The cytoprotective effect of estrogen was attenuated by addition of the estrogen receptor (ERα and ERβ) antagonist ICI 182,780 and the estrogen membrane receptor inhibitor G15. We showed that estrogen decreases not only oxidative stress but also ER stress to protect against 40mM glucose-induced pancreatic β-cell death.
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Affiliation(s)
- Suwattanee Kooptiwut
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Prannok Road, Bangkok 10700, Thailand.
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