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Anindya R, Rutter GA, Meur G. New-onset type 1 diabetes and severe acute respiratory syndrome coronavirus 2 infection. Immunol Cell Biol 2023; 101:191-203. [PMID: 36529987 PMCID: PMC9877852 DOI: 10.1111/imcb.12615] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/09/2022] [Accepted: 12/16/2022] [Indexed: 12/23/2022]
Abstract
Type 1 diabetes (T1D) is a condition characterized by an absolute deficiency of insulin. Loss of insulin-producing pancreatic islet β cells is one of the many causes of T1D. Viral infections have long been associated with new-onset T1D and the balance between virulence and host immunity determines whether the viral infection would lead to T1D. Herein, we detail the dynamic interaction of pancreatic β cells with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the host immune system with respect to new-onset T1D. Importantly, β cells express the crucial entry receptors and multiple studies confirmed that β cells are infected by SARS-CoV-2. Innate immune system effectors, such as natural killer cells, can eliminate such infected β cells. Although CD4+ CD25+ FoxP3+ regulatory T (TREG ) cells provide immune tolerance to prevent the destruction of the islet β-cell population by autoantigen-specific CD8+ T cells, it can be speculated that SARS-CoV-2 infection may compromise self-tolerance by depleting TREG -cell numbers or diminishing TREG -cell functions by repressing Forkhead box P3 (FoxP3) expression. However, the expansion of β cells by self-duplication, and regeneration from progenitor cells, could effectively replace lost β cells. Appearance of islet autoantibodies following SARS-CoV-2 infection was reported in a few cases, which could imply a breakdown of immune tolerance in the pancreatic islets. However, many of the cases with newly diagnosed autoimmune response following SARS-CoV-2 infection also presented with significantly high HbA1c (glycated hemoglobin) levels that indicated progression of an already set diabetes, rather than new-onset T1D. Here we review the potential underlying mechanisms behind loss of functional β-cell mass as a result of SARS-CoV-2 infection that can trigger new-onset T1D.
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Affiliation(s)
- Roy Anindya
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Sangareddy, Telangana, India
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore City, Singapore.,Centre of Research of Centre Hospitalier de l'Université de Montréal (CRCHUM), Faculty of Medicine, University of Montréal, Montréal, QC, Canada
| | - Gargi Meur
- ICMR-National Institute of Nutrition, Hyderabad, Telangana, India
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2
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Sharma S, Aggarwal S, Kulkarni R, Kumar D, Mishra BK, Dwivedi GR, Devi KR, Mamidi RS, Singh KJ, Singh L, Sahu D, Adhikari T, Nair S, Kumar A, Juneja A, Sharma A, Begum S, Surve S, Prusty RK, Kumar S, Geddam JJB, Meur G, Mummadi MK, Kailash U, Palo SK, Kanungo S, Kshatri JS, Behera AK, Swain S, Singh R, Zaman K, Deval H, Pandey AK, Sarkar A, Kant R, Narain K, D’Aquino L, Gaym A, Singh VV, Rao MVV. Challenges in Accessing and Delivering Maternal and Child Health Services during the COVID-19 Pandemic: A Cross-Sectional Rapid Survey from Six States of India. Int J Environ Res Public Health 2023; 20:1538. [PMID: 36674296 PMCID: PMC9865999 DOI: 10.3390/ijerph20021538] [Citation(s) in RCA: 1] [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] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND/OBJECTIVES Globally, the COVID-19 pandemic and its prevention and control policies have impacted maternal and child health (MCH) services. This study documents the challenges faced by patients in accessing MCH services, and the experiences of health care providers in delivering those services during the COVID-19 outbreak, explicitly focusing on the lockdown period in India. METHODS A cross-sectional study (rapid survey) was conducted in 18 districts from 6 states of India during March to June, 2020. The sample size included 540 MCH patients, 18 gynaecologists, 18 paediatricians, 18 district immunisation officers and 108 frontline health workers. Bivariate analysis and multivariable analysis were used to assess the association between sociodemographic characteristics, and challenges faced by the patients. RESULTS More than one-third of patients (n = 212; 39%) reported that accessing MCH services was a challenge during the lockdown period, with major challenges being transportation-related difficulties (n = 99; 46%) unavailability of hospital-based services (n = 54; 23%) and interrupted outreach health services (n = 39; 18.4%). The supply-side challenges mainly included lack of infrastructural preparedness for outbreak situations, and a shortage of human resources. CONCLUSIONS/RECOMMENDATIONS A holistic approach is required that focuses on both preparedness and response to the outbreak, as well reassignment and reinforcement of health care professionals to continue catering to and maintaining essential MCH services during the pandemic.
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Affiliation(s)
- Saurabh Sharma
- National Institute of Medical Statistics, Ansari Nagar, New Delhi 110029, India
| | - Sumit Aggarwal
- Indian Council of Medical Research, Ansari Nagar, New Delhi 110029, India
| | - Ragini Kulkarni
- National Institute for Research in Reproductive Health, Mumbai 400012, India
| | - Dinesh Kumar
- National Institute for Research in Tribal Health, Jabalpur 482003, India
| | | | | | - K. Rekha Devi
- Regional Medical Research Centre, NE Region, Dibrugarh 751023, India
| | | | | | - Lucky Singh
- National Institute of Medical Statistics, Ansari Nagar, New Delhi 110029, India
| | - Damodar Sahu
- National Institute of Medical Statistics, Ansari Nagar, New Delhi 110029, India
| | - Tulsi Adhikari
- National Institute of Medical Statistics, Ansari Nagar, New Delhi 110029, India
| | - Saritha Nair
- National Institute of Medical Statistics, Ansari Nagar, New Delhi 110029, India
| | - Anil Kumar
- National Institute of Medical Statistics, Ansari Nagar, New Delhi 110029, India
| | - Atul Juneja
- National Institute of Medical Statistics, Ansari Nagar, New Delhi 110029, India
| | - Anshita Sharma
- National Institute of Medical Statistics, Ansari Nagar, New Delhi 110029, India
| | - Shahina Begum
- National Institute for Research in Reproductive Health, Mumbai 400012, India
| | - Suchitra Surve
- National Institute for Research in Reproductive Health, Mumbai 400012, India
| | - Ranjan Kumar Prusty
- National Institute for Research in Reproductive Health, Mumbai 400012, India
| | - Surendra Kumar
- National Institute for Research in Reproductive Health, Mumbai 400012, India
| | | | - Gargi Meur
- National Institute of Nutrition, Hyderabad 500007, India
| | | | - Uma Kailash
- National Institute of Nutrition, Hyderabad 500007, India
| | | | | | | | | | | | - Rajeev Singh
- Regional Medical Research Centre, Gorakhpur 273013, India
| | - Kamran Zaman
- Regional Medical Research Centre, Gorakhpur 273013, India
| | - Hirawati Deval
- Regional Medical Research Centre, Gorakhpur 273013, India
| | | | - Abu Sarkar
- Regional Medical Research Centre, NE Region, Dibrugarh 751023, India
| | - Rajni Kant
- Regional Medical Research Centre, Gorakhpur 273013, India
| | - Kanwar Narain
- Regional Medical Research Centre, NE Region, Dibrugarh 751023, India
| | | | - Asheber Gaym
- UNICEF, India Country Office, New Delhi 110003, India
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Surekha MV, Suneetha N, Balakrishna N, Putcha UK, Satyanarayana K, Geddam JJB, Sreenu P, Tulja B, Mamidi RS, Rutter GA, Meur G. Impact of COVID-19 during pregnancy on placental pathology, maternal and neonatal outcome - A cross-sectional study on anemic term pregnant women from a tertiary care hospital in southern India. Front Endocrinol (Lausanne) 2023; 14:1092104. [PMID: 37025411 PMCID: PMC10070875 DOI: 10.3389/fendo.2023.1092104] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 03/03/2023] [Indexed: 04/08/2023] Open
Abstract
BACKGROUND SARS-CoV-2 infection during pregnancy may cause adverse maternal, neonatal and placental outcomes. While tissue hypoxia is often reported in COVID-19 patients, pregnant women with anemia are suspected to be more prone to placental hypoxia-related injuries. METHODS This hospital-based cross-sectional study was conducted between August-November 2021, during COVID-19 second wave in India. Term pregnant women (N=212) admitted to hospital for delivery were enrolled consecutively. Since hospital admission mandated negative RT-PCR test for SARS-CoV-2 virus, none had active infection. Data on socio-demography, COVID-19 history, maternal, obstetric, and neonatal outcomes were recorded. Pre-delivery maternal and post-delivery cord blood samples were tested for hematological parameters and SARS-CoV-2 IgG. Placentae were studied for histology. RESULTS Of 212 women, 122 (58%) were seropositive for SARS-CoV-2 IgG, but none reported COVID-19 history; 134 (63.2%) were anemic. In seropositive women, hemoglobin (p=0.04), total WBC (p=0.009), lymphocytes (p=0.005) and neutrophils (p=0.02) were significantly higher, while ferritin was high, but not significant and neutrophils to lymphocytes (p=0.12) and platelets to lymphocytes ratios (p=0.03) were lower. Neonatal outcomes were similar. All RBC parameters and serum ferritin were significantly lower in anemic mothers but not in cord blood, except RDW that was significantly higher in both, maternal (p=0.007) and cord (p=0.008) blood from seropositive anemic group compared to other groups. Placental histology showed significant increase in villous hypervascularity (p=0.000), dilated villous capillaries (p=0.000), and syncytiotrophoblasts (p=0.02) in seropositive group, typically suggesting placental hypoxia. Maternal anemia was not associated with any histological parameters. Univariate and multivariate logistic regression analyses of placental histopathological adverse outcomes showed strong association with SARS-CoV-2 seropositivity but not with maternal anemia. When adjusted for several covariates, including anemia, SARS-CoV-2 seropositivity emerged as independent risk factor for severe chorangiosis (AOR 8.74, 95% CI 3.51-21.76, p<0.000), dilated blood vessels (AOR 12.74, 95% CI 5.46-29.75, p<0.000), syncytiotrophoblasts (AOR 2.86, 95% CI 1.36-5.99, p=0.005) and villus agglutination (AOR 9.27, 95% CI 3.68-23.32, p<0.000). CONCLUSION Asymptomatic COVID-19 during pregnancy seemed to be associated with various abnormal placental histopathologic changes related to placental hypoxia independent of maternal anemia status. Our data supports an independent role of SARS-CoV-2 in causing placental hypoxia in pregnant women.
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Affiliation(s)
- M. V. Surekha
- Pathology and Microbiology Division, Indian Council of Medical Research-National Institute of Nutrition, Hyderabad, India
- *Correspondence: M.V. Surekha, ; ; Gargi Meur,
| | - N. Suneetha
- Obstetrics & Gynecology Department, Government Area Hospital, Nampally, Hyderabad, India
| | - N. Balakrishna
- Department of Statistics, Apollo Hospitals Educational and Research Foundation (AHERF), Hyderabad, India
| | - Uday Kumar Putcha
- Pathology and Microbiology Division, Indian Council of Medical Research-National Institute of Nutrition, Hyderabad, India
| | - K. Satyanarayana
- Pathology and Microbiology Division, Indian Council of Medical Research-National Institute of Nutrition, Hyderabad, India
| | - J. J. Babu Geddam
- Clinical Epidemiology Division, Indian Council of Medical Research-National Institute of Nutrition, Hyderabad, India
| | - Pagidoju Sreenu
- Clinical Epidemiology Division, Indian Council of Medical Research-National Institute of Nutrition, Hyderabad, India
| | - B. Tulja
- Clinical Epidemiology Division, Indian Council of Medical Research-National Institute of Nutrition, Hyderabad, India
| | - Raja Sriswan Mamidi
- Clinical Division, Indian Council of Medical Research-National Institute of Nutrition, Hyderabad, India
| | - Guy A. Rutter
- Centre of Research of Centre Hospitalier de l'Université de Montréal (CRCHUM), Faculty of Medicine, University of Montreal, Montreal, QC, Canada
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Gargi Meur
- Cell Biology Division, Indian Council of Medical Research-National Institute of Nutrition, Hyderabad, India
- *Correspondence: M.V. Surekha, ; ; Gargi Meur,
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Mamidi RS, Banjara SK, Manchala S, Babu CK, Geddam JJB, Boiroju NK, Varanasi B, Neeraja G, Reddy GVR, Ramalakshmi BA, Hemalatha R, Meur G. Maternal Nutrition, Body Composition and Gestational Weight Gain on Low Birth Weight and Small for Gestational Age-A Cohort Study in an Indian Urban Slum. Children (Basel) 2022; 9:children9101460. [PMID: 36291396 PMCID: PMC9600910 DOI: 10.3390/children9101460] [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] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/10/2022] [Accepted: 09/13/2022] [Indexed: 01/16/2023]
Abstract
Maternal nutritional status and care during pregnancy are essential for adequate birth weight. In this prospective cohort study (N = 1061) in an urban slum, we investigated the association of maternal anthropometry, body composition, gestational weight gain and dietary intakes with low birthweight (LBW, <2.5 kg). About one-third of the women were short (<150 cm), 35% were underweight (<45 kg), 23% suffered from chronic energy deficiency (CED, BMI < 18.5 kg/m2) and another 30% were overweight/obese. The mean age and BMI were 23 years and 21.7 kg/m2, respectively, and haemoglobin was 10.73 g/dL. The mean birthweight (N = 605) was 2.81 ± 0.5 kg, and the average gestational age was 38 ± 2 weeks. About 15% of infants had LBW, and 48% were small for gestational age (SGA). Maternal body composition was assessed by skinfold thickness (SFT) in all trimesters. In the first trimester (N = 762), we found that mean fat-free mass (FFM), fat mass (FM) and body fat percentage (% BF) were 38.86 kg, 11.43 kg and 21.55%, respectively. Low birthweight was significantly associated with preterm deliveries (p < 0.001) and less fat free mass (p = 0.02) in the third trimester. Among other factors were age (p = 0.017), maternal anthropometry (height: p = 0.031; weight: p = 0.059) and fewer antenatal check-ups (p = 0.037). Small size (SGA) was consistently associated with maternal bodyweight at all trimesters (term I, p = 0.013, term II, p = 0.003 and term III, p < 0.001), fat mass in the third trimester (p < 0.001) and maternal height (p = 0.003).
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Affiliation(s)
- Raja Sriswan Mamidi
- Clinical Epidemiology Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | | | - Sridevi Manchala
- Clinical Epidemiology Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | - Ch Khadar Babu
- Clinical Epidemiology Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | - J. J. Babu Geddam
- Clinical Epidemiology Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | - Naveen Kumar Boiroju
- Clinical Epidemiology Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | - Bhaskar Varanasi
- Public Health Nutrition, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | - G. Neeraja
- Public Health Nutrition, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | - G. Venkat Raji Reddy
- Clinical Epidemiology Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | - B. A. Ramalakshmi
- Clinical Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
| | - R. Hemalatha
- Clinical Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
- Correspondence: (R.H.); (G.M.); Tel.: +91-4027197200 (R.H.); +91-4027197472 (G.M.)
| | - Gargi Meur
- Clinical Epidemiology Division, ICMR-National Institute of Nutrition, Hyderabad 500 007, India
- Correspondence: (R.H.); (G.M.); Tel.: +91-4027197200 (R.H.); +91-4027197472 (G.M.)
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5
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Pai SS, Ranjan S, Mathew AR, Anindya R, Meur G. Analysis of the long-read sequencing data using computational tools confirms the presence of 5-methylcytosine in the Saccharomyces cerevisiae genome. Access Microbiol 2022; 4:acmi000363. [PMID: 36004362 PMCID: PMC9394670 DOI: 10.1099/acmi.0.000363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/27/2022] [Indexed: 11/18/2022] Open
Abstract
Modification of DNA bases plays important roles in the epigenetic regulation of eukaryotic gene expression. Among the different types of DNA methylation, 5-methylcytosine (5mC) is common in higher eukaryotes. Although bisulfite sequencing is the established detection method for this modification, newer methods, such as Oxford nanopore sequencing, have been developed as quick and reliable alternatives. An earlier study using sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) indicated the presence of 5mC at very low concentration in Saccharomyces cerevisiae. More recently, a comprehensive study of the yeast genome found 40 5mC sites using the computational tool Nanopolish on nanopore sequencing output raw data. In the present study, we are trying to validate the prediction of the 5mC modifications in yeast with Nanopolish and two other nanopore software tools, Tombo and DeepSignal. Using publicly available genome sequencing data, we compared the open-access computational tools, including Tombo, Nanopolish and DeepSignal, for predicting 5mC. Our results suggest that these tools are indeed capable of predicting DNA 5mC modifications at a specific location from Oxford nanopore sequencing data. We also predicted that 5mC present in the S. cerevisiae genome might be located predominantly at the RDN locus of chromosome 12.
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Affiliation(s)
- Shruta Sandesh Pai
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy-502284, India
| | - Saumya Ranjan
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy-502284, India
| | - Aimee Rachel Mathew
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy-502284, India
| | - Roy Anindya
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy-502284, India
| | - Gargi Meur
- National Institute of Nutrition, Hyderabad-500007, India
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Mehta ZB, Fine N, Pullen TJ, Cane MC, Hu M, Chabosseau P, Meur G, Velayos-Baeza A, Monaco AP, Marselli L, Marchetti P, Rutter GA. Changes in the expression of the type 2 diabetes-associated gene VPS13C in the β-cell are associated with glucose intolerance in humans and mice. Am J Physiol Endocrinol Metab 2016; 311:E488-507. [PMID: 27329800 PMCID: PMC5005967 DOI: 10.1152/ajpendo.00074.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 06/20/2016] [Indexed: 12/31/2022]
Abstract
Single nucleotide polymorphisms (SNPs) close to the VPS13C, C2CD4A and C2CD4B genes on chromosome 15q are associated with impaired fasting glucose and increased risk of type 2 diabetes. eQTL analysis revealed an association between possession of risk (C) alleles at a previously implicated causal SNP, rs7163757, and lowered VPS13C and C2CD4A levels in islets from female (n = 40, P < 0.041) but not from male subjects. Explored using promoter-reporter assays in β-cells and other cell lines, the risk variant at rs7163757 lowered enhancer activity. Mice deleted for Vps13c selectively in the β-cell were generated by crossing animals bearing a floxed allele at exon 1 to mice expressing Cre recombinase under Ins1 promoter control (Ins1Cre). Whereas Vps13c(fl/fl):Ins1Cre (βVps13cKO) mice displayed normal weight gain compared with control littermates, deletion of Vps13c had little effect on glucose tolerance. Pancreatic histology revealed no significant change in β-cell mass in KO mice vs. controls, and glucose-stimulated insulin secretion from isolated islets was not altered in vitro between control and βVps13cKO mice. However, a tendency was observed in female null mice for lower insulin levels and β-cell function (HOMA-B) in vivo. Furthermore, glucose-stimulated increases in intracellular free Ca(2+) were significantly increased in islets from female KO mice, suggesting impaired Ca(2+) sensitivity of the secretory machinery. The present data thus provide evidence for a limited role for changes in VPS13C expression in conferring altered disease risk at this locus, particularly in females, and suggest that C2CD4A may also be involved.
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Affiliation(s)
- Zenobia B Mehta
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
| | - Nicholas Fine
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
| | - Timothy J Pullen
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
| | - Matthew C Cane
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
| | - Ming Hu
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
| | - Gargi Meur
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
| | | | - Anthony P Monaco
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom; and
| | - Lorella Marselli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom;
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7
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Seillier M, Pouyet L, N'Guessan P, Nollet M, Capo F, Guillaumond F, Peyta L, Dumas JF, Varrault A, Bertrand G, Bonnafous S, Tran A, Meur G, Marchetti P, Ravier MA, Dalle S, Gual P, Muller D, Rutter GA, Servais S, Iovanna JL, Carrier A. Defects in mitophagy promote redox-driven metabolic syndrome in the absence of TP53INP1. EMBO Mol Med 2016; 7:802-18. [PMID: 25828351 PMCID: PMC4459819 DOI: 10.15252/emmm.201404318] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The metabolic syndrome covers metabolic abnormalities including obesity and type 2 diabetes (T2D). T2D is characterized by insulin resistance resulting from both environmental and genetic factors. A genome-wide association study (GWAS) published in 2010 identified TP53INP1 as a new T2D susceptibility locus, but a pathological mechanism was not identified. In this work, we show that mice lacking TP53INP1 are prone to redox-driven obesity and insulin resistance. Furthermore, we demonstrate that the reactive oxygen species increase in TP53INP1-deficient cells results from accumulation of defective mitochondria associated with impaired PINK/PARKIN mitophagy. This chronic oxidative stress also favors accumulation of lipid droplets. Taken together, our data provide evidence that the GWAS-identified TP53INP1 gene prevents metabolic syndrome, through a mechanism involving prevention of oxidative stress by mitochondrial homeostasis regulation. In conclusion, this study highlights TP53INP1 as a molecular regulator of redox-driven metabolic syndrome and provides a new preclinical mouse model for metabolic syndrome clinical research.
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Affiliation(s)
- Marion Seillier
- Inserm, U1068, CRCM, Marseille, France Institut Paoli-Calmettes, Marseille, France Aix-Marseille Université, Marseille, France CNRS, UMR7258, CRCM, Marseille, France
| | - Laurent Pouyet
- Inserm, U1068, CRCM, Marseille, France Institut Paoli-Calmettes, Marseille, France Aix-Marseille Université, Marseille, France CNRS, UMR7258, CRCM, Marseille, France
| | - Prudence N'Guessan
- Inserm, U1068, CRCM, Marseille, France Institut Paoli-Calmettes, Marseille, France Aix-Marseille Université, Marseille, France CNRS, UMR7258, CRCM, Marseille, France
| | - Marie Nollet
- Inserm, U1068, CRCM, Marseille, France Institut Paoli-Calmettes, Marseille, France Aix-Marseille Université, Marseille, France CNRS, UMR7258, CRCM, Marseille, France
| | - Florence Capo
- Inserm, U1068, CRCM, Marseille, France Institut Paoli-Calmettes, Marseille, France Aix-Marseille Université, Marseille, France CNRS, UMR7258, CRCM, Marseille, France
| | - Fabienne Guillaumond
- Inserm, U1068, CRCM, Marseille, France Institut Paoli-Calmettes, Marseille, France Aix-Marseille Université, Marseille, France CNRS, UMR7258, CRCM, Marseille, France
| | - Laure Peyta
- Inserm, U1069 Nutrition, Croissance et Cancer (N2C), Tours, France
| | | | - Annie Varrault
- CNRS, UMR5203, Inserm, U661 Universités de Montpellier 1 & 2, IGF, Montpellier, France
| | - Gyslaine Bertrand
- CNRS, UMR5203, Inserm, U661 Universités de Montpellier 1 & 2, IGF, Montpellier, France
| | - Stéphanie Bonnafous
- Inserm, U1065, C3M Team 8 "Hepatic Complications in Obesity", Nice, France Université de Nice-Sophia-Antipolis, Nice, France Centre Hospitalier Universitaire de Nice, Pôle Digestif Hôpital L'Archet, Nice, France
| | - Albert Tran
- Inserm, U1065, C3M Team 8 "Hepatic Complications in Obesity", Nice, France Université de Nice-Sophia-Antipolis, Nice, France Centre Hospitalier Universitaire de Nice, Pôle Digestif Hôpital L'Archet, Nice, France
| | - Gargi Meur
- Cell Biology, Department of Medicine, Imperial College, London, UK
| | - Piero Marchetti
- Islet Cell Laboratory, University of Pisa - Cisanello Hospital, Pisa, Italy
| | - Magalie A Ravier
- CNRS, UMR5203, Inserm, U661 Universités de Montpellier 1 & 2, IGF, Montpellier, France
| | - Stéphane Dalle
- CNRS, UMR5203, Inserm, U661 Universités de Montpellier 1 & 2, IGF, Montpellier, France
| | - Philippe Gual
- Inserm, U1065, C3M Team 8 "Hepatic Complications in Obesity", Nice, France Université de Nice-Sophia-Antipolis, Nice, France Centre Hospitalier Universitaire de Nice, Pôle Digestif Hôpital L'Archet, Nice, France
| | - Dany Muller
- CNRS, UMR5203, Inserm, U661 Universités de Montpellier 1 & 2, IGF, Montpellier, France
| | - Guy A Rutter
- Cell Biology, Department of Medicine, Imperial College, London, UK
| | - Stéphane Servais
- Inserm, U1069 Nutrition, Croissance et Cancer (N2C), Tours, France
| | - Juan L Iovanna
- Inserm, U1068, CRCM, Marseille, France Institut Paoli-Calmettes, Marseille, France Aix-Marseille Université, Marseille, France CNRS, UMR7258, CRCM, Marseille, France
| | - Alice Carrier
- Inserm, U1068, CRCM, Marseille, France Institut Paoli-Calmettes, Marseille, France Aix-Marseille Université, Marseille, France CNRS, UMR7258, CRCM, Marseille, France
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Mitchell RK, Hu M, Chabosseau PL, Cane MC, Meur G, Bellomo EA, Carzaniga R, Collinson LM, Li WH, Hodson DJ, Rutter GA. Molecular Genetic Regulation of Slc30a8/ZnT8 Reveals a Positive Association With Glucose Tolerance. Mol Endocrinol 2015; 30:77-91. [PMID: 26584158 PMCID: PMC4995240 DOI: 10.1210/me.2015-1227] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Zinc transporter 8 (ZnT8), encoded by SLC30A8, is chiefly expressed within pancreatic islet cells, where it mediates zinc (Zn2+) uptake into secretory granules. Although a common nonsynonymous polymorphism (R325W), which lowers activity, is associated with increased type 2 diabetes (T2D) risk, rare inactivating mutations in SLC30A8 have been reported to protect against T2D. Here, we generate and characterize new mouse models to explore the impact on glucose homeostasis of graded changes in ZnT8 activity in the β-cell. Firstly, Slc30a8 was deleted highly selectively in these cells using the novel deleter strain, Ins1Cre. The resultant Ins1CreZnT8KO mice displayed significant (P < .05) impairments in glucose tolerance at 10 weeks of age vs littermate controls, and glucose-induced increases in circulating insulin were inhibited in vivo. Although insulin release from Ins1CreZnT8KO islets was normal, Zn2+ release was severely impaired. Conversely, transgenic ZnT8Tg mice, overexpressing the transporter inducibly in the adult β-cell using an insulin promoter-dependent Tet-On system, showed significant (P < .01) improvements in glucose tolerance compared with control animals. Glucose-induced insulin secretion from ZnT8Tg islets was severely impaired, whereas Zn2+ release was significantly enhanced. Our findings demonstrate that glucose homeostasis in the mouse improves as β-cell ZnT8 activity increases, and remarkably, these changes track Zn2+ rather than insulin release in vitro. Activation of ZnT8 in β-cells might therefore provide the basis of a novel approach to treating T2D.
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Affiliation(s)
- Ryan K Mitchell
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Ming Hu
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Pauline L Chabosseau
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Matthew C Cane
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Gargi Meur
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Elisa A Bellomo
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Raffaella Carzaniga
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Lucy M Collinson
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Wen-Hong Li
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - David J Hodson
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics (R.K.M., M.H., P.L.C., M.C.C., G.M., E.A.B., D.J.H., G.A.R.), Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom; Electron Microscopy Unit (R.C., L.M.C.), Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, United Kingdom; and Department of Cell Biology and Biochemistry (W.-H.L.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390
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Meur G, Shukla P, Dutta-Gupta A, Kirti P. Characterization of Brassica juncea–Alternaria brassicicola interaction and jasmonic acid carboxyl methyl transferase expression. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.plgene.2015.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Solomou A, Meur G, Bellomo E, Hodson DJ, Tomas A, Li SM, Philippe E, Herrera PL, Magnan C, Rutter GA. The Zinc Transporter Slc30a8/ZnT8 Is Required in a Subpopulation of Pancreatic α-Cells for Hypoglycemia-induced Glucagon Secretion. J Biol Chem 2015; 290:21432-42. [PMID: 26178371 PMCID: PMC4571871 DOI: 10.1074/jbc.m115.645291] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Indexed: 12/02/2022] Open
Abstract
SLC30A8 encodes a zinc transporter ZnT8 largely restricted to pancreatic islet β- and α-cells, and responsible for zinc accumulation into secretory granules. Although common SLC30A8 variants, believed to reduce ZnT8 activity, increase type 2 diabetes risk in humans, rare inactivating mutations are protective. To investigate the role of Slc30a8 in the control of glucagon secretion, Slc30a8 was inactivated selectively in α-cells by crossing mice with alleles floxed at exon 1 to animals expressing Cre recombinase under the pre-proglucagon promoter. Further crossing to Rosa26:tdRFP mice, and sorting of RFP+: glucagon+ cells from KO mice, revealed recombination in ∼30% of α-cells, of which ∼50% were ZnT8-negative (14 ± 1.8% of all α-cells). Although glucose and insulin tolerance were normal, female αZnT8KO mice required lower glucose infusion rates during hypoglycemic clamps and displayed enhanced glucagon release (p < 0.001) versus WT mice. Correspondingly, islets isolated from αZnT8KO mice secreted more glucagon at 1 mm glucose, but not 17 mm glucose, than WT controls (n = 5; p = 0.008). Although the expression of other ZnT family members was unchanged, cytoplasmic (n = 4 mice per genotype; p < 0.0001) and granular (n = 3, p < 0.01) free Zn2+ levels were significantly lower in KO α-cells versus control cells. In response to low glucose, the amplitude and frequency of intracellular Ca2+ increases were unchanged in α-cells of αZnT8KO KO mice. ZnT8 is thus important in a subset of α-cells for normal responses to hypoglycemia and acts via Ca2+-independent mechanisms.
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Affiliation(s)
- Antonia Solomou
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Gargi Meur
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Elisa Bellomo
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - David J Hodson
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Alejandra Tomas
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom, the Department of Cell Biology, Institute of Ophthalmology, University College London, Greater London EC1V 9EL, United Kingdom
| | - Stéphanie Migrenne Li
- the University Paris Diderot-Paris 7, Unit of Functional and Adaptive Biology (BFA) EAC 7059 CNRS, 75013 Paris, France, and
| | - Erwann Philippe
- the University Paris Diderot-Paris 7, Unit of Functional and Adaptive Biology (BFA) EAC 7059 CNRS, 75013 Paris, France, and
| | - Pedro L Herrera
- the Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, 1 rue Michel-Servet, 1211 Geneva-4, Switzerland
| | - Christophe Magnan
- the University Paris Diderot-Paris 7, Unit of Functional and Adaptive Biology (BFA) EAC 7059 CNRS, 75013 Paris, France, and
| | - Guy A Rutter
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom,
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11
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Chabosseau P, Tuncay E, Meur G, Bellomo EA, Hessels A, Hughes S, Johnson PRV, Bugliani M, Marchetti P, Turan B, Lyon AR, Merkx M, Rutter GA. Mitochondrial and ER-targeted eCALWY probes reveal high levels of free Zn2+. ACS Chem Biol 2014; 9:2111-20. [PMID: 25011072 PMCID: PMC6101202 DOI: 10.1021/cb5004064] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Zinc (Zn2+) ions are increasingly recognized as playing an important role in cellular physiology. Whereas the free Zn2+ concentration in the cytosol has been established to be 0.1-1 nM, the free Zn2+ concentration in subcellular organelles is not well-established. Here, we extend the eCALWY family of genetically encoded Förster Resonance Energy Transfer (FRET) Zn2+ probes to permit measurements in the endo(sarco)plasmic reticulum (ER) and mitochondrial matrix. Deployed in a variety of mammalian cell types, these probes reveal resting mitochondrial free [Zn2+] values of ∼300 pM, somewhat lower than in the cytosol but 3 orders of magnitude higher than recently reported using an alternative FRET-based sensor. By contrast, free ER [Zn2+] was found to be ≥5 nM, which is >5000-fold higher than recently reported but consistent with the proposed role of the ER as a mobilizable Zn2+ store. Treatment of β-cells or cardiomyocytes with sarco(endo)plasmic reticulum Ca2+-ATPase inhibitors, mobilization of ER Ca2+ after purinergic stimulation with ATP, or manipulation of ER redox, exerted no detectable effects on [Zn2+]ER. These findings question the previously proposed role of Ca2+ in Zn2+ mobilization from the ER and suggest that high ER Zn2+ levels may be an important aspect of cellular homeostasis.
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Affiliation(s)
- Pauline Chabosseau
- Section of Cell Biology, Division of Medicine, and ‡National Heart and Lung Institute, Imperial College London , London, United Kingdom
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12
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Gerber PA, Bellomo EA, Hodson DJ, Meur G, Solomou A, Mitchell RK, Hollinshead M, Chimienti F, Bosco D, Hughes SJ, Johnson PRV, Rutter GA. Hypoxia lowers SLC30A8/ZnT8 expression and free cytosolic Zn2+ in pancreatic beta cells. Diabetologia 2014; 57:1635-44. [PMID: 24865615 PMCID: PMC4079946 DOI: 10.1007/s00125-014-3266-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [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: 01/13/2014] [Accepted: 04/23/2014] [Indexed: 12/16/2022]
Abstract
AIMS/HYPOTHESIS Hypoxic damage complicates islet isolation for transplantation and may contribute to beta cell failure in type 2 diabetes. Polymorphisms in the SLC30A8 gene, encoding the secretory granule zinc transporter 8 (ZnT8), influence type 2 diabetes risk, conceivably by modulating cytosolic Zn(2+) levels. We have therefore explored the role of ZnT8 and cytosolic Zn(2+) in the response to hypoxia of pancreatic islet cells. METHODS Human, mouse or rat islets were isolated and exposed to varying O2 tensions. Cytosolic free zinc was measured using the adenovirally expressed recombinant targeted zinc probe eCALWY4. Gene expression was measured using quantitative (q)RT-PCR, western (immuno-) blotting or immunocytochemistry. Beta cells were identified by insulin immunoreactivity. RESULTS Deprivation of O2 (1% vs 5% or 21%) for 24 h lowered free cytosolic Zn(2+) concentrations by ~40% (p < 0.05) and ~30% (p < 0.05) in mouse and human islet cells, respectively. Hypoxia similarly decreased SLC30A8 mRNA expression in islets, and immunoreactivity in beta cells. Implicating lowered ZnT8 levels in the hypoxia-induced fall in cytosolic Zn(2+), genetic ablation of Slc30a8 from mouse islets lowered cytosolic Zn(2+) by ~40% (p < 0.05) and decreased the induction of metallothionein (Mt1, Mt2) genes. Cell survival in the face of hypoxia was enhanced in small islets of older (>12 weeks) Slc30a8 null mice vs controls, but not younger animals. CONCLUSIONS/INTERPRETATION The response of pancreatic beta cells to hypoxia is characterised by decreased SLC30A8 expression and lowered cytosolic Zn(2+) concentrations. The dependence on ZnT8 of hypoxia-induced changes in cell survival may contribute to the actions of SLC30A8 variants on diabetes risk in humans.
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Affiliation(s)
- Philipp A. Gerber
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 ONN UK
- Division of Endocrinology, Diabetes and Clinical Nutrition, University Hospital Zurich, Zurich, Switzerland
| | - Elisa A. Bellomo
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 ONN UK
| | - David J. Hodson
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 ONN UK
| | - Gargi Meur
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 ONN UK
| | - Antonia Solomou
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 ONN UK
| | - Ryan K. Mitchell
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 ONN UK
| | - Michael Hollinshead
- Section of Microscopy, Department of Medicine, Imperial College London, London, UK
| | | | - Domenico Bosco
- Cell Isolation and Transplantation Centre, Department of Surgery, Geneva University Hospital, Geneva, Switzerland
| | - Stephen J. Hughes
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
- DRWF Human Islet Isolation Facility, Oxford Centre for Diabetes, Endocrinology and Metabolism, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Oxford, UK
| | - Paul R. V. Johnson
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
- DRWF Human Islet Isolation Facility, Oxford Centre for Diabetes, Endocrinology and Metabolism, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Oxford, UK
| | - Guy A. Rutter
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 ONN UK
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Abstract
Carbohydrate-responsive element binding protein (ChREBP (MLXIPL)) is emerging as an important mediator of glucotoxity both in the liver and in the pancreatic β-cells. Although the regulation of its nuclear translocation and transcriptional activation by glucose has been the subject of intensive research, it is still not fully understood. We have recently uncovered a novel mechanism in the excitable pancreatic β-cell where ChREBP interacts with sorcin, a penta-EF-hand Ca(2)(+)-binding protein, and is sequestered in the cytosol at low glucose concentrations. Upon stimulation with glucose and activation of Ca(2)(+) influx, or application of ATP as an intracellular Ca(2)(+)-mobilising agent, ChREBP rapidly translocates to the nucleus. In sorcin-silenced cells, ChREBP is constitutively present in the nucleus, and both glucose and Ca(2)(+) are ineffective in stimulating further ChREBP nuclear shuttling. Whether an active Ca(2)(+)-sorcin element of ChREBP activation also exists in non-excitable cells is discussed.
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Affiliation(s)
- Isabelle Leclerc
- Division of Diabetes, Endocrinology and Metabolism, Section of Cell Biology, Department of Medicine, Imperial College London, SW7 2AZ London, UK.
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14
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Abstract
Carbohydrate-responsive element-binding protein (ChREBP) is a regulator of pancreatic β-cell gene expression and an important mediator of glucotoxicity. Glucose increases the activity and nuclear localization of ChREBP by still ill-defined mechanisms. Here we reveal, using both MIN6 and primary mouse β-cells, a unique mechanism behind ChREBP nuclear translocation. At low glucose concentrations, ChREBP interacts with sorcin, a penta EF hand Ca(2+) binding protein, and is sequestered in the cytosol. Sorcin overexpression inhibits ChREBP nuclear accumulation at high glucose and reduced the activity of L-type pyruvate kinase (L-PK) and TxNIP promoters, two well-characterized ChREBP target genes. Sorcin inactivation by RNA interference increases ChREBP nuclear localization and in vivo binding to the L-PK promoter at low glucose concentrations. Ca(2+) influx was essential for this process since Ca(2+) chelation with EGTA, or pharmacological inhibition with diazoxide and nifedipine, blocked the effects of glucose. Conversely, mobilization of intracellular Ca(2+) with ATP caused the nuclear accumulation of ChREBP. Finally, sorcin silencing inhibited ATP-induced increases in intracellular Ca(2+) and glucose-stimulated insulin secretion. We therefore conclude that sorcin retains ChREBP in the cytosol at low glucose concentrations and may act as a Ca(2+) sensor for glucose-induced nuclear translocation and the activation of ChREBP-dependent genes.
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Affiliation(s)
| | | | - Guy A. Rutter
- Corresponding authors: Guy A. Rutter, , and Isabelle Leclerc,
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15
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Semplici F, Vaxillaire M, Fogarty S, Semache M, Bonnefond A, Fontés G, Philippe J, Meur G, Diraison F, Sessions RB, Rutter J, Poitout V, Froguel P, Rutter GA. Human mutation within Per-Arnt-Sim (PAS) domain-containing protein kinase (PASK) causes basal insulin hypersecretion. J Biol Chem 2011; 286:44005-44014. [PMID: 22065581 PMCID: PMC3243507 DOI: 10.1074/jbc.m111.254995] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PAS kinase (PASK) is a glucose-regulated protein kinase involved in the control of pancreatic islet hormone release and insulin sensitivity. We aimed here to identify mutations in the PASK gene that may be associated with young-onset diabetes in humans. We screened 18 diabetic probands with unelucidated maturity-onset diabetes of the young (MODY). We identified two rare nonsynonymous mutations in the PASK gene (p.L1051V and p.G1117E), each of which was found in a single MODY family. Wild type or mutant PASKs were expressed in HEK 293 cells. Kinase activity of the affinity-purified proteins was assayed as autophosphorylation at amino acid Thr307 or against an Ugp1p-derived peptide. Whereas the PASK p.G1117E mutant displayed a ∼25% increase with respect to wild type PASK in the extent of autophosphorylation, and a ∼2-fold increase in kinase activity toward exogenous substrates, the activity of the p.L1051V mutant was unchanged. Amino acid Gly1117 is located in an α helical region opposing the active site of PASK and may elicit either: (a) a conformational change that increases catalytic efficiency or (b) a diminished inhibitory interaction with the PAS domain. Mouse islets were therefore infected with adenoviruses expressing wild type or mutant PASK and the regulation of insulin secretion was examined. PASK p.G1117E-infected islets displayed a 4-fold decrease in glucose-stimulated (16.7 versus 3 mM) insulin secretion, chiefly reflecting a 4.5-fold increase in insulin release at low glucose. In summary, we have characterized a rare mutation (p.G1117E) in the PASK gene from a young-onset diabetes family, which modulates glucose-stimulated insulin secretion.
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Affiliation(s)
- Francesca Semplici
- Department of Medicine, Section of Cell Biology, Division of Diabetes Endocrinology and Metabolism, Imperial College London, London SW7 2AZ, United Kingdom
| | - Martine Vaxillaire
- CNRS-UMR-8199, Pasteur Institute of Lille, BP245 59019 Lille Cedex, France; Lille Nord de France University, BP245 59019 Lille Cedex, France
| | - Sarah Fogarty
- University of Utah School of Medicine, Salt Lake City, Utah 84132-3201
| | - Meriem Semache
- Montreal Diabetes Research Center, CRCHUM, University of Montréal, Québec, Canada
| | - Amélie Bonnefond
- CNRS-UMR-8199, Pasteur Institute of Lille, BP245 59019 Lille Cedex, France; Lille Nord de France University, BP245 59019 Lille Cedex, France
| | - Ghislaine Fontés
- Montreal Diabetes Research Center, CRCHUM, University of Montréal, Québec, Canada
| | - Julien Philippe
- CNRS-UMR-8199, Pasteur Institute of Lille, BP245 59019 Lille Cedex, France; Lille Nord de France University, BP245 59019 Lille Cedex, France
| | - Gargi Meur
- Department of Medicine, Section of Cell Biology, Division of Diabetes Endocrinology and Metabolism, Imperial College London, London SW7 2AZ, United Kingdom
| | - Frederique Diraison
- Centre for Research in Biomedicine, Faculty of Health and Life Sciences, University of the West of England, Bristol BS16 1QY, United Kingdom
| | - Richard B Sessions
- Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Jared Rutter
- University of Utah School of Medicine, Salt Lake City, Utah 84132-3201
| | - Vincent Poitout
- Montreal Diabetes Research Center, CRCHUM, University of Montréal, Québec, Canada; Department of Medicine, University of Montréal, Montréal QC H1W 4A4 Québec, Canada
| | - Philippe Froguel
- CNRS-UMR-8199, Pasteur Institute of Lille, BP245 59019 Lille Cedex, France; Lille Nord de France University, BP245 59019 Lille Cedex, France; Department of Genomics of Common Disease, School of Public Health, Imperial College London, London SW7 2AZ, United Kingdom
| | - Guy A Rutter
- Department of Medicine, Section of Cell Biology, Division of Diabetes Endocrinology and Metabolism, Imperial College London, London SW7 2AZ, United Kingdom.
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16
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Bellomo EA, Meur G, Rutter GA. Glucose regulates free cytosolic Zn²⁺ concentration, Slc39 (ZiP), and metallothionein gene expression in primary pancreatic islet β-cells. J Biol Chem 2011; 286:25778-89. [PMID: 21613223 PMCID: PMC3138249 DOI: 10.1074/jbc.m111.246082] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [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] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 05/13/2011] [Indexed: 12/15/2022] Open
Abstract
Zn²⁺ is an important cofactor for insulin biosynthesis and storage in pancreatic β-cells. Correspondingly, polymorphisms in the SLC30A8 gene, encoding the secretory granule Zn²⁺ transporter ZnT8, are associated with type 2 diabetes risk. Using a genetically engineered (FRET)-based sensor (eCALWY-4), we show here that elevated glucose time-dependently increases free cytosolic Zn²⁺ ([Zn²⁺](cyt)) in mouse pancreatic β-cells. These changes become highly significant (853 ± 96 pm versus 452 ± 42 pm, p < 0.001) after 24 h and are associated with increased expression of the Zn²⁺ importer family members Slc39a6, Slc39a7, and Slc39a8, and decreased expression of metallothionein 1 and 2. Arguing that altered expression of the above genes is not due to altered [Zn²⁺](cyt), elevation of extracellular (and intracellular) [Zn²⁺] failed to mimic the effects of high glucose. By contrast, increases in intracellular cAMP prompted by 3-isobutyl-1-methylxanthine and forskolin partially mimicked the effects of glucose on metallothionein, although not ZiP, gene expression. Modulation of intracellular Ca²⁺ and insulin secretion with pharmacological agents (tolbutamide and diazoxide) suggested a possible role for changes in these parameters in the regulation of Slc39a6 and Slc39a7 but not Slc39a8, nor metallothionein expression. In summary, 1) glucose induces increases in [Zn²⁺](cyt), which are then likely to facilitate the processing and/or the storage of insulin and its cocrystallization with Zn²⁺, and 2) these increases are associated with elevated expression of zinc importers. Conversely, a chronic increase in [Zn²⁺](cyt) following sustained hyperglycemia may contribute to β-cell dysfunction and death in some forms of diabetes.
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Affiliation(s)
- Elisa A. Bellomo
- From the Section of Cell Biology, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Gargi Meur
- From the Section of Cell Biology, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Guy A. Rutter
- From the Section of Cell Biology, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, London SW7 2AZ, United Kingdom
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Meur G, Qian Q, da Silva Xavier G, Pullen TJ, Tsuboi T, McKinnon C, Fletcher L, Tavaré JM, Hughes S, Johnson P, Rutter GA. Nucleo-cytosolic shuttling of FoxO1 directly regulates mouse Ins2 but not Ins1 gene expression in pancreatic beta cells (MIN6). J Biol Chem 2011; 286:13647-56. [PMID: 21335550 PMCID: PMC3075709 DOI: 10.1074/jbc.m110.204248] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [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] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 02/14/2011] [Indexed: 01/26/2023] Open
Abstract
The Forkhead box transcription factor FoxO1 regulates metabolic gene expression in mammals. FoxO1 activity is tightly controlled by phosphatidylinositol 3-kinase (PI3K) signaling, resulting in its phosphorylation and nuclear exclusion. We sought here to determine the mechanisms involved in glucose and insulin-stimulated nuclear shuttling of FoxO1 in pancreatic β cells and its consequences for preproinsulin (Ins1, Ins2) gene expression. Nuclear-localized endogenous FoxO1 translocated to the cytosol in response to elevated glucose (3 versus 16.7 mM) in human islet β cells. Real-time confocal imaging of nucleo-cytosolic shuttling of a FoxO1-EGFP chimera in primary mouse and clonal MIN6 β cells revealed a time-dependent glucose-responsive nuclear export, also mimicked by exogenous insulin, and blocked by suppressing insulin secretion. Constitutively active PI3K or protein kinase B/Akt exerted similar effects, while inhibitors of PI3K, but not of glycogen synthase kinase-3 or p70 S6 kinase, blocked nuclear export. FoxO1 overexpression reversed the activation by glucose of pancreatic duodenum homeobox-1 (Pdx1) transcription. Silencing of FoxO1 significantly elevated the expression of mouse Ins2, but not Ins1, mRNA at 3 mM glucose. Putative FoxO1 binding sites were identified in the distal promoter of rodent Ins2 genes and direct binding of FoxO1 to the Ins2 promoter was demonstrated by chromatin immunoprecipitation. A 915-bp glucose-responsive Ins2 promoter was inhibited by constitutively active FoxO1, an effect unaltered by simultaneous overexpression of PDX1. We conclude that nuclear import of FoxO1 contributes to the suppression of Pdx1 and Ins2 gene expression at low glucose, the latter via a previously unsuspected and direct physical interaction with the Ins2 promoter.
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Affiliation(s)
- Gargi Meur
- From the Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Qingwen Qian
- From the Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Gabriela da Silva Xavier
- From the Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Timothy J. Pullen
- From the Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
| | - Takashi Tsuboi
- the Department of Life Sciences, University of Tokyo, Tokyo 153-8902, Japan
| | - Caroline McKinnon
- From the Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
- the Henry Wellcome Laboratories for Integrated Cell Signalling and Department of Biochemistry, School of Medical Sciences, University Walk, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Laura Fletcher
- the Henry Wellcome Laboratories for Integrated Cell Signalling and Department of Biochemistry, School of Medical Sciences, University Walk, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Jeremy M. Tavaré
- the Henry Wellcome Laboratories for Integrated Cell Signalling and Department of Biochemistry, School of Medical Sciences, University Walk, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Stephen Hughes
- the Nuffield Department of Surgery, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom, and
| | - Paul Johnson
- the Nuffield Department of Surgery, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom, and
| | - Guy A. Rutter
- From the Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
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Meur G, Simon A, Harun N, Virally M, Dechaume A, Bonnefond A, Fetita S, Tarasov AI, Guillausseau PJ, Boesgaard TW, Pedersen O, Hansen T, Polak M, Gautier JF, Froguel P, Rutter GA, Vaxillaire M. Insulin gene mutations resulting in early-onset diabetes: marked differences in clinical presentation, metabolic status, and pathogenic effect through endoplasmic reticulum retention. Diabetes 2010; 59:653-61. [PMID: 20007936 PMCID: PMC2828668 DOI: 10.2337/db09-1091] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [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] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Heterozygous mutations in the human preproinsulin (INS) gene are a cause of nonsyndromic neonatal or early-infancy diabetes. Here, we sought to identify INS mutations associated with maturity-onset diabetes of the young (MODY) or nonautoimmune diabetes in mid-adult life, and to explore the molecular mechanisms involved. RESEARCH DESIGN AND METHODS The INS gene was sequenced in 16 French probands with unexplained MODY, 95 patients with nonautoimmune early-onset diabetes (diagnosed at <35 years) and 292 normoglycemic control subjects of French origin. Three identified insulin mutants were generated by site-directed mutagenesis of cDNA encoding a preproinsulin-green fluorescent protein (GFP) (C-peptide) chimera. Intracellular targeting was assessed in clonal beta-cells by immunocytochemistry and proinsulin secretion, by radioimmunoassay. Spliced XBP1 and C/EBP homologous protein were quantitated by real-time PCR. RESULTS A novel coding mutation, L30M, potentially affecting insulin multimerization, was identified in five diabetic individuals (diabetes onset 17-36 years) in a single family. L30M preproinsulin-GFP fluorescence largely associated with the endoplasmic reticulum (ER) in MIN6 beta-cells, and ER exit was inhibited by approximately 50%. Two additional mutants, R55C (at the B/C junction) and R6H (in the signal peptide), were normally targeted to secretory granules, but nonetheless caused substantial ER stress. CONCLUSIONS We describe three INS mutations cosegregating with early-onset diabetes whose clinical presentation is compatible with MODY. These led to the production of (pre)proinsulin molecules with markedly different trafficking properties and effects on ER stress, demonstrating a range of molecular defects in the beta-cell.
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Affiliation(s)
- Gargi Meur
- Section of Cell Biology, Division of Medicine, Imperial College London, London, U.K
| | - Albane Simon
- Universite Paris Descartes, INSERM U845, Pediatric Endocrinology, Hopital Necker Enfants Malades Paris, Paris, France
| | - Nasret Harun
- Section of Cell Biology, Division of Medicine, Imperial College London, London, U.K
| | - Marie Virally
- Department of Endocrinology and Diabetes, Lariboisière Hospital, University Paris-Diderot Paris-7, Paris, France
| | - Aurélie Dechaume
- Centre National de la Recherche Scientifique-UMR8090, Lille Institute of Biology, Lille 2 University, Pasteur Institute, Lille, France
| | - Amélie Bonnefond
- Centre National de la Recherche Scientifique-UMR8090, Lille Institute of Biology, Lille 2 University, Pasteur Institute, Lille, France
| | - Sabrina Fetita
- Department of Endocrinology and Diabetes, Clinical Investigation Center CIC9504, Saint-Louis Hospital, INSERM, U872, University Paris-Diderot Paris-7, Paris, France
| | - Andrei I. Tarasov
- Section of Cell Biology, Division of Medicine, Imperial College London, London, U.K
| | - Pierre-Jean Guillausseau
- Department of Endocrinology and Diabetes, Lariboisière Hospital, University Paris-Diderot Paris-7, Paris, France
| | | | - Oluf Pedersen
- Hagedorn Research Institute and Steno Diabetes Center, Gentofte, Denmark
- Faculty of Health Science, University of Aarhus, Aarhus, Denmark
- Institute of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Torben Hansen
- Hagedorn Research Institute and Steno Diabetes Center, Gentofte, Denmark
- Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Michel Polak
- Universite Paris Descartes, INSERM U845, Pediatric Endocrinology, Hopital Necker Enfants Malades Paris, Paris, France
| | - Jean-François Gautier
- Department of Endocrinology and Diabetes, Clinical Investigation Center CIC9504, Saint-Louis Hospital, INSERM, U872, University Paris-Diderot Paris-7, Paris, France
| | - Philippe Froguel
- Centre National de la Recherche Scientifique-UMR8090, Lille Institute of Biology, Lille 2 University, Pasteur Institute, Lille, France
- Genomic Medicine, Hammersmith Hospital, Imperial College, London, U.K
| | - Guy A. Rutter
- Section of Cell Biology, Division of Medicine, Imperial College London, London, U.K
- Corresponding authors: Guy A. Rutter, , or Philippe Froguel,
| | - Martine Vaxillaire
- Centre National de la Recherche Scientifique-UMR8090, Lille Institute of Biology, Lille 2 University, Pasteur Institute, Lille, France
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Srinivasan T, Kumar KRR, Meur G, Kirti PB. Heterologous expression of Arabidopsis NPR1 (AtNPR1) enhances oxidative stress tolerance in transgenic tobacco plants. Biotechnol Lett 2009; 31:1343-51. [PMID: 19466562 DOI: 10.1007/s10529-009-0022-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 04/01/2009] [Accepted: 05/07/2009] [Indexed: 12/25/2022]
Abstract
In Arabidopsis, NPR1 (non-expressor of pathogenesis related genes 1, AtNPR1) functions downstream of salicylic acid (SA) and modulates the SA mediated systemic acquired resistance. It is also involved in a cross talk with the jasmonate pathway that is essential for resistance against herbivores and necrotrophic pathogens. Overexpression of AtNPR1 in transgenic plants resulted in enhanced disease resistance. Recently, tobacco transgenic plants expressing AtNPR1 were shown to be tolerant to the early instars of Spodoptera litura (Meur et al., Physiol Plant 133:765-775, 2008). In this communication, we show that the heterologous expression of AtNPR1 in tobacco has also enhanced the oxidative stress tolerance. The transgenic plants exhibited enhanced tolerance to the treatment with methyl viologen. This tolerance was associated with the constitutive upregulation of PR1, PR2 (glucanase), PR5 (thaumatin like protein), ascorbate peroxidase (APX) and Cu(2+)/Zn(2+) superoxide dismutase (SOD). This is the first demonstration of the novel function of heterologous expression of AtNPR1 in oxidative stress tolerance in transgenic tobacco.
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Affiliation(s)
- T Srinivasan
- Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India
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Abstract
Ryanodine receptors (RyR) are Ca2+ channels that mediate
Ca2+ release from intracellular stores in response to diverse
intracellular signals. In RINm5F insulinoma cells, caffeine, and
4-chloro-m-cresol (4CmC), agonists of RyR, stimulated Ca2+
entry that was independent of store-operated Ca2+ entry, and
blocked by prior incubation with a concentration of ryanodine that inactivates
RyR. Patch-clamp recording identified small numbers of large-conductance
(γK = 169 pS) cation channels that were activated by
caffeine, 4CmC or low concentrations of ryanodine. Similar channels were
detected in rat pancreatic β-cells. In RINm5F cells, the channels were
blocked by cytosolic, but not extracellular, ruthenium red. Subcellular
fractionation showed that type 3 IP3 receptors (IP3R3)
were expressed predominantly in endoplasmic reticulum, whereas RyR2 were
present also in plasma membrane fractions. Using RNAi selectively to reduce
expression of RyR1, RyR2, or IP3R3, we showed that RyR2 mediates
both the Ca2+ entry and the plasma membrane currents evoked by
agonists of RyR. We conclude that small numbers of RyR2 are selectively
expressed in the plasma membrane of RINm5F pancreatic β-cells, where they
mediate Ca2+ entry.
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Affiliation(s)
- Christian Rosker
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom
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Srinivasan T, Kumar KR, Meur G, Kirti P. Heterologous expression of Arabidopsis Npr1 modulates insect resistance and abiotic stress tolerance also in tobacco transgenic plants. J Biotechnol 2008. [DOI: 10.1016/j.jbiotec.2008.07.501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Meur G, Budatha M, Srinivasan T, Rajesh Kumar KR, Dutta Gupta A, Kirti PB. Constitutive expression of Arabidopsis NPR1 confers enhanced resistance to the early instars of Spodoptera litura in transgenic tobacco. Physiol Plant 2008; 133:765-75. [PMID: 18397206 DOI: 10.1111/j.1399-3054.2008.01098.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In Arabidopsis, NPR1 (AtNPR1) regulates salicylic acid (SA)-mediated activation of PR genes at the onset of systemic acquired resistance. AtNPR1 also modulates SA-induced suppression of jasmonic acid-responsive gene expression, and npr1 mutants manifest enhanced herbivore resistance. We have raised stable transgenic tobacco lines, expressing AtNPR1 constitutively, which showed elevated expression of PR1 and PR2 genes upon SA treatment. Herbivore bioassays with a generalist polyphagous pest, Spodoptera litura, revealed that the transgenic lines exhibited enhanced resistance compared to the wild-type plants, particularly with respect to younger larval populations. Insect-mediated injury induced several protease inhibitors (PIs), more significantly a 40-kDa serine PI in all the tobacco lines, but the induction was higher in the transgenic plants. We show in this communication that heterologous expression of AtNPR1 provides enhanced resistance to early larval populations of the herbivore, Spodoptera in transgenic tobacco plants.
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Affiliation(s)
- Gargi Meur
- School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
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Budatha M, Meur G, Vimala Devi PS, Kirti PB, Dutta-Gupta A. Characterization of Bacillus thuringiensis strain DOR4 toxic to castor semilooper Achaea janata: proteolytic processing and binding of toxins to receptors. Curr Microbiol 2008; 57:72-7. [PMID: 18437459 DOI: 10.1007/s00284-008-9155-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2007] [Accepted: 01/18/2008] [Indexed: 11/24/2022]
Abstract
We have isolated a strain of Bacillus thuringiensis (Bt) from Indian soil samples that was shown to be toxic to Achaea janata larvae. The isolate, named B. thuringiensis DOR4, serotypically identified with the standard subspecies kurstaki (H3a3b3c) and produced bipyramidal inclusions along with an amorphous type. Although the plasmid pattern of DOR4 was different from that of the reference strain, a crystal protein profile showed the presence of two major bands (130 and 65 kDa) similar to those of Bt subsp. kurstaki HD-1. To verify the cry gene content of DOR4, triplex PCR analysis was performed; it showed amplification of the cry1C gene in addition to cry1Aa, cry1Ac, cry2A, and cry2B genes, but not the cry1Ab gene. RT-PCR analysis showed the expression of cry1Aa and cry1Ac genes. In vitro proteolysis of DOR4 protoxin with midgut extract generated products of different sizes. Zymogram analysis of DOR4 protoxin as substrate pointed to a number of distinct proteases that were responsible for activation of protoxins. Furthermore, toxin overlay analysis revealed the presence of multiple toxin-binding proteins in midgut epithelium. Based on all these characterizations, we suggest that the Bt DOR4 strain can be exploited for an A. janata control program.
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Budatha M, Meur G, Dutta-Gupta A. Identification and characterization of midgut proteases in Achaea janata and their implications. Biotechnol Lett 2007; 30:305-10. [PMID: 17891457 DOI: 10.1007/s10529-007-9539-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 08/30/2007] [Accepted: 08/31/2007] [Indexed: 11/28/2022]
Abstract
Insect midgut proteases are excellent targets for insecticidal agents such as Bacillus thuringiensis Cry toxins and protease inhibitors. The midgut proteases of Achaea janata have been characterized and Casein zymograms indicated at least five distinct activities corresponding to approx 17, 20, 29 and 80, and 90 kDa. Using a combination of synthetic substrates and specific inhibitors in casein zymograms, photometric assays and activity blots, three trypsin-like and one elastase-like serine proteases were identified but no chymotrypsin-like activity. Various proteinase inhibitors displayed differential inhibitory effects towards the midgut proteases.
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Budatha M, Meur G, Dutta-Gupta A. A novel aminopeptidase in the fat body of the moth Achaea janata as a receptor for Bacillus thuringiensis Cry toxins and its comparison with midgut aminopeptidase. Biochem J 2007; 405:287-97. [PMID: 17402938 PMCID: PMC1904524 DOI: 10.1042/bj20070054] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [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: 11/17/2022]
Abstract
Bacillus thuringiensis insecticidal crystal proteins bind to cell-surface receptors which represent a family of aminopeptidases [APN (aminopeptidase N)] present on the brush border membrane of insect midgut cells of susceptible insects leading to pore formation and death of the insect. We report here for the first time the presence of a novel APN in the fat body of the moth Achaea janata. Northern blotting detected at least one APN-specific transcript in the fat body, whereas two transcripts of different sizes were detected in the midgut. We have cloned two full-length APN cDNAs of 3015 bp and 2850 bp from fat body and midgut respectively, which encode proteins of 1004 and 950 amino acids. These two APNs share only 33% amino acid sequence identity, but both display the typical APN features, such as the N-terminal signal peptide, several putative glycosylation sites, C-terminal glycosylphosphatidylinositol anchor signal, the APN-specific zinc-binding/gluzincin motif HEXXHX(18)E and gluzincin motif GAMENWG. The fat body APN manifested a variation in its expression with respect to tissue and developmental stage. In spite of the abundance of the APN transcript in the fat body, fairly low APN activity was detected in this tissue. The fat-body- and midgut-specific APNs showed differential interaction with various Cry1A toxins. Besides, the level of toxicity of different Cry subtypes varied enormously with mode/site of delivery, such as intrahaemocoelic injections and feeding bioassays. These data indicate that the fat body might be a potential alternative Cry toxin target site in the moth.
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Affiliation(s)
| | - Gargi Meur
- School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Aparna Dutta-Gupta
- School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
- To whom correspondence should be addressed (email )
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Budatha M, Meur G, Kirti PB, Dutta Gupta A. Characterization of Bacillus thuringiensis Cry toxin binding novel GPI anchored aminopeptidase from fat body of the moth Spodoptera litura. Biotechnol Lett 2007; 29:1651-7. [PMID: 17609853 DOI: 10.1007/s10529-007-9453-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 06/12/2007] [Accepted: 06/13/2007] [Indexed: 11/28/2022]
Abstract
Aminopeptidase N (APN) isoforms were identified as candidate receptors for Bacillus thuringiensis Cry toxins from the midgut of several insect species. In this study a partial cDNA encoding aminopeptidase (slfbAPN) was cloned from fat body of the moth Spodoptera litura. In the deduced amino acid sequence the characteristic metallopeptidase sequences, HEXXHX(18)E and GAMENWG were conserved but the sequence showed only 33-39% identity to other insect APNs, which were also reported to be Cry toxin receptors. The presence of a putative GPI anchor signal sequence at the C-terminus indicated that it is a membrane-anchored protein. The slfbAPN expression was restricted to the fat body as suggested by northern blot analysis of different tissues. Biochemical analyses including immunoblotting, ligand blotting and lectin blotting, demonstrated that slfbAPN is a membrane-anchored glycoprotein in the fat body and it binds to Cry toxins.
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Abstract
Most ryanodine receptors and their relatives, inositol 1,4,5-trisphosphate receptors, are expressed in the sarcoplasmic or endoplasmic reticulum (ER), where they mediate Ca(2+) release. We expressed fragments of ryanodine receptor type 1 (RyR1) in COS cells alone or fused to intercellular adhesion molecule-1 (ICAM-1), each tagged with yellow fluorescent protein, and used confocal imaging and glycoprotein analysis to identify the determinants of ER targeting and retention. Single transmembrane domains (TMD) of RyR1 taken from the first (TMD1-TMD2) or last (TMD5-TMD6) pair were expressed in the ER membrane. TMD3-TMD4 was expressed in the outer mitochondrial membrane. The TMD outer pairs (TMD1-TMD2 and TMD5-TMD6) retained ICAM-1, a plasma membrane-targeted protein, within the ER membrane. TMD1 alone provided a strong ER retention signal and TMD6 a weaker signal, but the other single TMD were unable to retain ICAM-1 in the ER. We conclude that TMD1 provides the first and sufficient signal for ER targeting of RyR1. The TMD outer pairs include redundant ER retention signals, with TMD1 providing the strongest signal.
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Affiliation(s)
- Gargi Meur
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
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Meur G, Gaikwad K, Bhat SR, Prakash S, Kirti PB. Homeotic-like modification of stamens to petals is associated with aberrant mitochondrial gene expression in cytoplasmic male sterile Ogura Brassica juncea. J Genet 2006; 85:133-9. [PMID: 17072082 DOI: 10.1007/bf02729019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [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: 10/22/2022]
Abstract
We have previously reported correction of severe leaf chlorosis in the cytoplasmic male sterile Ogura (also called Ogu) Brassica juncea line carrying Ogura cytoplasm by plastid substitution via protoplast fusion. Two cybrids obtained from the fusion experiment, Og1 and Og2, were green and carried the plastid genome of B. juncea cv. RLM198. While Og1 displayed normal flower morphology comparable to that of its euplasmic B. juncea counterpart except for sterile anthers, Og2 retained homeotic-like floral modification of stamens to petal-like structures and several other floral deformities observed in the chlorotic (Ogu) B. juncea cv. RLM198 (or OgRLM). With respect to the mitochondrial genome, Og1 showed 81% genetic similarity to the fertile cultivar RLM while Og2 showed 93% similarity to OgRLM. In spite of recombination and rearrangements in the mitochondrial genomes in the cybrids, expression patterns of 10 out of 11 mitochondrial genes were similar in all the three CMS lines; the only exception was atp6, whose expression was altered. While Og1 showed normal atp6 transcript similar to that in RLM, in Og2 and OgRLM weak expression of a longer transcript was detected. These results suggest that the homeotic-like changes in floral patterning leading to petaloid stamens in Og2 and OgRLM may be associated with aberrant mitochondrial gene expression.
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Affiliation(s)
- Gargi Meur
- Department of Plant Sciences, University of Hyderabad, Hyderabad 500 046, India
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Meur G. [The artificial lens: the folly of yesterday, the standard of today]. Bull Mem Acad R Med Belg 2000; 154:273-8; discussion 278-80. [PMID: 10687245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Traditional cataract operation (dislocation of the crystalline lens into the vitreous body by external pressure or by needling) is nearly as old as mankind. The idea of implanting an artificial lenticulus is not new but this was only performed for the first time in 1949. In the last 50 years, a better knowledge of corneal and retinal physiology, as well as the improvements of intraocular lens material and design, have led to very safe routine surgery.
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Meur G, Meur-Terfve L. [Peri-ocular anesthesia by unique caruncular injection in surgery of the anterior segment]. Bull Soc Belge Ophtalmol 1998; 268:111-3. [PMID: 9810091] [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: 02/09/2023]
Abstract
PURPOSE To evaluate the efficacy and safety of medial canthus local anesthesia in anterior segment surgery. METHODS From December 1st 1996 to October 24th 1997, 234 patients underwent anterior segment surgery under caruncular single injection anesthesia: cataract, phacotrabeculectomy, corneal graft and triple procedure. RESULTS The technique achieved good globe anesthesia and lid and orbital muscle akinesia. Neither globe perforation nor lid ecchymoses were observed. CONCLUSION Caruncular single injection appears to be a good alternative to classical peribulbar block.
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Affiliation(s)
- G Meur
- Institut Edith Cavell, Bruxelles
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Metge P, Meur G. About encircling haptics. J Cataract Refract Surg 1998; 24:1170. [PMID: 9768386 DOI: 10.1016/s0886-3350(98)80004-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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32
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Maenhaut M, Meur G. [Incidence of cystoid macular edema in the implant of retro-pupillary lenses]. Ophtalmologie 1987; 1:431-3. [PMID: 3153910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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33
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Meur G. A new capsule supported intraocular lens. Ophthalmic Surg 1987; 18:395-6. [PMID: 3601350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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34
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Meur G, Maenhaut M, Szyper C. [Implantation of an intra-ocular lens in a case of crystallin ectopy]. Ophtalmologie 1987; 1:257-60. [PMID: 3153864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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35
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Meur G, Frankental D. [Ocular hypotension and cataract in pregnancy, apropos of a case]. Bull Soc Belge Ophtalmol 1980; 187:83-87. [PMID: 7470711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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36
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Lawwill T, Meur G. Retinal rivalry in functional amblyopia. Arch Ophthalmol 1979; 97:1100-2. [PMID: 444142 DOI: 10.1001/archopht.1979.01020010554009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Thirteen patients with varying degrees of amblyopia were examined for perception of retinal rivalry with the use of the phase difference haploscope. Visual acuity was varied in the fixing eye by the addition of plus lenses, equalizing ocular dominance. Retinal rivalry could be detected over wide ranges of visual acuity disparity by amblyopic patients with visual acuity better than 20/50. Rivalry could not be detected, however, by patients with less than 20/50 visual acuity in their amblyopic eye.
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37
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Meur G. [Character of perimetric defects in retinal diseases]. J Fr Ophtalmol 1978; 1:163-9. [PMID: 149814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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38
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Meur G. [Injuries of the uvea]. Arch Ophtalmol (Paris) 1976; 36:349-52. [PMID: 135550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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39
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40
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Meur G, Conreur L. [Influence of dazzle in an eye on the state of adaptation of the contralateral eye in a normal subject]. Vision Res 1973; 13:1005-8. [PMID: 4713915 DOI: 10.1016/0042-6989(73)90139-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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41
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Lawwill T, Cox WE, Tuttle D, Meur G, Burian HM. Lateral inhibition and the VER in the central field of an amblyopic subject. Invest Ophthalmol 1973; 12:154-6. [PMID: 4683667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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42
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Meur G, Flament-Durand J, Denis R, Verougstraete C. [Retinal tumor and cerebral tumor: a case]. Bull Soc Belge Ophtalmol 1971; 159:661-70. [PMID: 5151377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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43
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Danis P, Meur G. [Lowe's oculo-cerebro-renal syndrome (histologic ocular study of 2 cases)]. Bull Soc Belge Ophtalmol 1971; 159:555-64. [PMID: 5151371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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44
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Danis P, Meur G. [The summation phenomenon in strabismic amblyopia]. Doc Ophthalmol 1967; 23:203-9. [PMID: 5583477 DOI: 10.1007/bf02550748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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45
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Meur G, Detilleux JM. [Statistical analysis of various sensory characteristics in healthy and amblyopic patients]. Bull Soc Belge Ophtalmol 1967; 147:438-45. [PMID: 5621797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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46
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Conreur L, Meur G. [Influence of wavelength of the light stimulus in the phenomenon of retinal spacial summation]. Bull Soc Belge Ophtalmol 1966; 143:532-541. [PMID: 5981999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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47
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48
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Meur G. [Contribution to the study of retinal space summations]. Ann Ocul (Paris) 1965; 198:436-47. [PMID: 5833859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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