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Everman ER, Macdonald SJ. Gene expression variation underlying tissue-specific responses to copper stress in Drosophila melanogaster. G3 (BETHESDA, MD.) 2024; 14:jkae015. [PMID: 38262701 PMCID: PMC11021028 DOI: 10.1093/g3journal/jkae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/25/2024]
Abstract
Copper is one of a handful of biologically necessary heavy metals that is also a common environmental pollutant. Under normal conditions, copper ions are required for many key physiological processes. However, in excess, copper results in cell and tissue damage ranging in severity from temporary injury to permanent neurological damage. Because of its biological relevance, and because many conserved copper-responsive genes respond to nonessential heavy metal pollutants, copper resistance in Drosophila melanogaster is a useful model system with which to investigate the genetic control of the heavy metal stress response. Because heavy metal toxicity has the potential to differently impact specific tissues, we genetically characterized the control of the gene expression response to copper stress in a tissue-specific manner in this study. We assessed the copper stress response in head and gut tissue of 96 inbred strains from the Drosophila Synthetic Population Resource using a combination of differential expression analysis and expression quantitative trait locus mapping. Differential expression analysis revealed clear patterns of tissue-specific expression. Tissue and treatment specific responses to copper stress were also detected using expression quantitative trait locus mapping. Expression quantitative trait locus associated with MtnA, Mdr49, Mdr50, and Sod3 exhibited both genotype-by-tissue and genotype-by-treatment effects on gene expression under copper stress, illuminating tissue- and treatment-specific patterns of gene expression control. Together, our data build a nuanced description of the roles and interactions between allelic and expression variation in copper-responsive genes, provide valuable insight into the genomic architecture of susceptibility to metal toxicity, and highlight candidate genes for future functional characterization.
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Affiliation(s)
- Elizabeth R Everman
- School of Biological Sciences, The University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA
| | - Stuart J Macdonald
- Molecular Biosciences, University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045, USA
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Everman ER, Macdonald SJ. Gene expression variation underlying tissue-specific responses to copper stress in Drosophila melanogaster. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548746. [PMID: 37503205 PMCID: PMC10370140 DOI: 10.1101/2023.07.12.548746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Copper is one of a handful of biologically necessary heavy metals that is also a common environmental pollutant. Under normal conditions, copper ions are required for many key physiological processes. However, in excess, copper quickly results in cell and tissue damage that can range in severity from temporary injury to permanent neurological damage. Because of its biological relevance, and because many conserved copper-responsive genes also respond to other non-essential heavy metal pollutants, copper resistance in Drosophila melanogaster is a useful model system with which to investigate the genetic control of the response to heavy metal stress. Because heavy metal toxicity has the potential to differently impact specific tissues, we genetically characterized the control of the gene expression response to copper stress in a tissue-specific manner in this study. We assessed the copper stress response in head and gut tissue of 96 inbred strains from the Drosophila Synthetic Population Resource (DSPR) using a combination of differential expression analysis and expression quantitative trait locus (eQTL) mapping. Differential expression analysis revealed clear patterns of tissue-specific expression, primarily driven by a more pronounced gene expression response in gut tissue. eQTL mapping of gene expression under control and copper conditions as well as for the change in gene expression following copper exposure (copper response eQTL) revealed hundreds of genes with tissue-specific local cis-eQTL and many distant trans-eQTL. eQTL associated with MtnA, Mdr49, Mdr50, and Sod3 exhibited genotype by environment effects on gene expression under copper stress, illuminating several tissue- and treatment-specific patterns of gene expression control. Together, our data build a nuanced description of the roles and interactions between allelic and expression variation in copper-responsive genes, provide valuable insight into the genomic architecture of susceptibility to metal toxicity, and highlight many candidate genes for future functional characterization.
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Affiliation(s)
- Elizabeth R Everman
- 1200 Sunnyside Ave, University of Kansas, Molecular Biosciences, Lawrence, KS 66045, USA
- 730 Van Vleet Oval, University of Oklahoma, Biology, Norman, OK 73019, USA
| | - Stuart J Macdonald
- 1200 Sunnyside Ave, University of Kansas, Molecular Biosciences, Lawrence, KS 66045, USA
- 1200 Sunnyside Ave, University of Kansas, Center for Computational Biology, Lawrence, KS 66045, USA
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Lee JB, Kang YJ, Kim SG, Woo JH, Shin MC, Park NG, Yang BC, Han SH, Han KM, Lim HT, Ryu YC, Park HB, Cho IC. GWAS and Post-GWAS High-Resolution Mapping Analyses Identify Strong Novel Candidate Genes Influencing the Fatty Acid Composition of the Longissimus dorsi Muscle in Pigs. Genes (Basel) 2021; 12:1323. [PMID: 34573305 PMCID: PMC8468772 DOI: 10.3390/genes12091323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 12/02/2022] Open
Abstract
Fatty acid (FA) composition is one of the most important parameters for the assessment of meat quality in pigs. The FA composition in pork can also affect human health. Our aim was to identify quantitative trait loci (QTLs) and positional candidate genes affecting the FA profile of the longissimus dorsi muscle in a large F2 intercross between Landrace and Korean native pigs comprising 1105 F2 progeny by genome-wide association studies (GWAS) and post-GWAS high-resolution mapping analyses. We performed GWAS using the PorcineSNP60K BeadChip and a linear mixed model. Four genome-wide significant QTL regions in SSC8, SSC12, SSC14, and SSC16 were detected (p < 2.53 × 10-7). Several co-localizations of QTLs in SSC12 for oleic acid, linoleic acid, arachidonic acid, monounsaturated FAs, polyunsaturated FAs, and the polyunsaturated/saturated FA ratio were observed. To refine the QTL region in SSC12, a linkage and linkage disequilibrium analysis was applied and could narrow down the critical region to a 0.749 Mb region. Of the genes in this region, GAS7, MYH2, and MYH3 were identified as strong novel candidate genes based on further conditional association analyses. These findings provide a novel insight into the genetic basis of FA composition in pork and could contribute to the improvement of pork quality.
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Affiliation(s)
- Jae-Bong Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Iksan 54531, Korea;
| | - Yong-Jun Kang
- Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, Jeju 63242, Korea; (Y.-J.K.); (S.-G.K.); (J.-H.W.); (M.-C.S.); (N.-G.P.); (B.-C.Y.)
| | - Sang-Geum Kim
- Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, Jeju 63242, Korea; (Y.-J.K.); (S.-G.K.); (J.-H.W.); (M.-C.S.); (N.-G.P.); (B.-C.Y.)
| | - Jae-Hoon Woo
- Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, Jeju 63242, Korea; (Y.-J.K.); (S.-G.K.); (J.-H.W.); (M.-C.S.); (N.-G.P.); (B.-C.Y.)
| | - Moon-Cheol Shin
- Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, Jeju 63242, Korea; (Y.-J.K.); (S.-G.K.); (J.-H.W.); (M.-C.S.); (N.-G.P.); (B.-C.Y.)
| | - Nam-Geon Park
- Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, Jeju 63242, Korea; (Y.-J.K.); (S.-G.K.); (J.-H.W.); (M.-C.S.); (N.-G.P.); (B.-C.Y.)
| | - Byoung-Chul Yang
- Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, Jeju 63242, Korea; (Y.-J.K.); (S.-G.K.); (J.-H.W.); (M.-C.S.); (N.-G.P.); (B.-C.Y.)
| | - Sang-Hyun Han
- Species Restoration Technology Institute, Korea National Park Service, Yeongju 36015, Korea;
| | - Kang-Min Han
- Department of Pathology, Dongguk University Ilsan Hospital, Goyang 10326, Korea;
| | - Hyun-Tae Lim
- Department of Animal Science, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju 52828, Korea;
- Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Korea
| | - Youn-Chul Ryu
- Division of Biotechnology, Jeju National University, SARI, Jeju 63243, Korea;
| | - Hee-Bok Park
- Department of Animal Resources Science, Kongju National University, Yesan 32439, Korea
| | - In-Cheol Cho
- Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, Jeju 63242, Korea; (Y.-J.K.); (S.-G.K.); (J.-H.W.); (M.-C.S.); (N.-G.P.); (B.-C.Y.)
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Rushing A, Sommer EC, Zhao S, Po'e EK, Barkin SL. Salivary epigenetic biomarkers as predictors of emerging childhood obesity. BMC MEDICAL GENETICS 2020; 21:34. [PMID: 32059710 PMCID: PMC7023819 DOI: 10.1186/s12881-020-0968-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 02/06/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Epigenetics could facilitate greater understanding of disparities in the emergence of childhood obesity. While blood is a common tissue used in human epigenetic studies, saliva is a promising tissue. Our prior findings in non-obese preschool-aged Hispanic children identified 17 CpG dinucleotides for which differential methylation in saliva at baseline was associated with maternal obesity status. The current study investigated to what extent baseline DNA methylation in salivary samples in these 3-5-year-old Hispanic children predicted the incidence of childhood obesity in a 3-year prospective cohort. METHODS We examined a subsample (n = 92) of Growing Right Onto Wellness (GROW) trial participants who were randomly selected at baseline, prior to randomization, based on maternal phenotype (obese or non-obese). Baseline saliva samples were collected using the Oragene DNA saliva kit. Objective data were collected on child height and weight at baseline and 36 months later. Methylation arrays were processed using standard protocol. Associations between child obesity at 36 months and baseline salivary methylation at the previously identified 17 CpG dinucleotides were evaluated using multivariable logistic regression models. RESULTS Among the n = 75 children eligible for analysis, baseline methylation of Cg1307483 (NRF1) was significantly associated with emerging childhood obesity at 36-month follow-up (OR = 2.98, p = 0.04), after adjusting for child age, gender, child baseline BMI-Z, and adult baseline BMI. This translates to a model-estimated 48% chance of child obesity at 36-month follow-up for a child at the 75th percentile of NRF1 baseline methylation versus only a 30% chance of obesity for a similar child at the 25th percentile. Consistent with other studies, a higher baseline child BMI-Z during the preschool period was associated with the emergence of obesity 3 years later, but baseline methylation of NRF1 was associated with later obesity even after adjusting for child baseline BMI-Z. CONCLUSIONS Saliva offers a non-invasive means of DNA collection and epigenetic analysis. Our proof of principle study provides sound empirical evidence supporting DNA methylation in salivary tissue as a potential predictor of subsequent childhood obesity for Hispanic children. NFR1 could be a target for further exploration of obesity in this population.
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Affiliation(s)
- Amanda Rushing
- Louisiana State University Health Sciences Center, School of Medicine, 1901 Perdido Street, New Orleans, LA, 70112, USA
| | - Evan C Sommer
- Department of Pediatrics, Vanderbilt University Medical Center, 2146 Belcourt Ave, Nashville, TN, 37232-9225, USA
| | - Shilin Zhao
- Department of Biostatistics, Vanderbilt University Medical Center, 571 Preston Research Building, 2220 Pierce Ave, Nashville, TN, 37232-6838, USA
| | - Eli K Po'e
- Department of Pediatrics, Vanderbilt University Medical Center, 2146 Belcourt Ave, Nashville, TN, 37232-9225, USA
| | - Shari L Barkin
- Department of Pediatrics, Vanderbilt University School of Medicine, 2200 Children's Way, Doctor's Office Tower 8232, Nashville, TN, 37232-9225, USA.
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Null mutation of the endothelin receptor type B gene causes embryonic death in the GK rat. PLoS One 2019; 14:e0217132. [PMID: 31170185 PMCID: PMC6553694 DOI: 10.1371/journal.pone.0217132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 05/06/2019] [Indexed: 12/28/2022] Open
Abstract
The Hirschsprung disease (HSCR) is an inherited disease that is controlled by multiple genes and has a complicated genetic mechanism. HSCR patients suffer from various extents of constipation due to dysplasia of the enteric nervous system (ENS), which can be so severe as to cause complete intestinal obstruction. Many genes have been identified as playing causative roles in ENS dysplasia and HSCR, among them the endothelin receptor type B gene (Ednrb) has been identified to play an important role. Mutation of Ednrb causes a series of symptoms that include deafness, pigmentary abnormalities, and aganglionosis. In our previous studies of three rat models carrying the same spotting lethal (sl) mutation on Ednrb, the haplotype of a region on chromosome (Chr) 2 was found to be responsible for the differing severities of the HSCR-like symptoms. To confirm that the haplotype of the responsible region on Chr 2 modifies the severity of aganglionosis caused by Ednrb mutation and to recreate a rat model with severe symptoms, we selected the GK inbred strain, whose haplotype in the responsible region on Chr 2 resembles that of the rat strain in which severe symptoms accompany the Ednrbsl mutation. An Ednrb mutation was introduced into the GK rat by crossing with F344-Ednrbsl and by genome editing. The null mutation of Ednrb was found to cause embryonic death in F2 progeny possessing the GK haplotype in the responsible region on Chr 2. The results of this study are unexpected, and they provide new clues and animal models that promise to contribute to studies on the genetic regulatory network in the development of ENS and on embryogenesis.
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Knudsen JG, Hamilton A, Ramracheya R, Tarasov AI, Brereton M, Haythorne E, Chibalina MV, Spégel P, Mulder H, Zhang Q, Ashcroft FM, Adam J, Rorsman P. Dysregulation of Glucagon Secretion by Hyperglycemia-Induced Sodium-Dependent Reduction of ATP Production. Cell Metab 2019; 29:430-442.e4. [PMID: 30415925 PMCID: PMC6370947 DOI: 10.1016/j.cmet.2018.10.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 07/23/2018] [Accepted: 10/13/2018] [Indexed: 01/21/2023]
Abstract
Diabetes is a bihormonal disorder resulting from combined insulin and glucagon secretion defects. Mice lacking fumarase (Fh1) in their β cells (Fh1βKO mice) develop progressive hyperglycemia and dysregulated glucagon secretion similar to that seen in diabetic patients (too much at high glucose and too little at low glucose). The glucagon secretion defects are corrected by low concentrations of tolbutamide and prevented by the sodium-glucose transport (SGLT) inhibitor phlorizin. These data link hyperglycemia, intracellular Na+ accumulation, and acidification to impaired mitochondrial metabolism, reduced ATP production, and dysregulated glucagon secretion. Protein succination, reflecting reduced activity of fumarase, is observed in α cells from hyperglycemic Fh1βKO and β-V59M gain-of-function KATP channel mice, diabetic Goto-Kakizaki rats, and patients with type 2 diabetes. Succination is also observed in renal tubular cells and cardiomyocytes from hyperglycemic Fh1βKO mice, suggesting that the model can be extended to other SGLT-expressing cells and may explain part of the spectrum of diabetic complications.
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Affiliation(s)
- Jakob G Knudsen
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Alexander Hamilton
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Reshma Ramracheya
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Melissa Brereton
- Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Elizabeth Haythorne
- Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Margarita V Chibalina
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Peter Spégel
- Centre for Analysis and Synthesis, Lund University Diabetes Centre, Department of Chemistry, Naturvetarvägen 14, Lund 221 00, Sweden
| | - Hindrik Mulder
- Unit of Molecular Metabolism, Lund University Diabetes Centre, Department of Clinical Research in Malmö, Jan Waldenströms Gata 35, Malmö 205 02, Sweden
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Frances M Ashcroft
- Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Julie Adam
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK; Nuffield Department of Clinical Medicine, University of Oxford, NDM Research Building, Oxford OX3 7FZ, UK.
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK; Metabolic Research, Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Göteborg, Box 433, Göteborg 405 30, Sweden.
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Gloaguen E, Bendelac N, Nicolino M, Julier C, Mathieu F. A systematic review of non-genetic predictors and genetic factors of glycated haemoglobin in type 1 diabetes one year after diagnosis. Diabetes Metab Res Rev 2018; 34:e3051. [PMID: 30063815 DOI: 10.1002/dmrr.3051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 07/20/2018] [Accepted: 07/23/2018] [Indexed: 12/13/2022]
Abstract
Type 1 diabetes (T1D) results from autoimmune destruction of the pancreatic βcells. Although all T1D patients require daily administration of exogenous insulin, their insulin requirement to achieve good glycaemic control may vary significantly. Glycated haemoglobin (HbA1c) level represents a stable indicator of glycaemic control and is a reliable predictor of long-term complications of T1D. The purpose of this article is to systematically review the role of non-genetic predictors and genetic factors of HbA1c level in T1D patients after the first year of T1D, to exclude the honeymoon period. A total of 1974 articles published since January 2011 were identified and 78 were finally included in the analysis of non-genetic predictors. For genetic factors, a total of 277 articles were identified and 14 were included. The most significantly associated factors with HbA1c level are demographic (age, ethnicity, and socioeconomic status), personal (family characteristics, parental care, psychological traits...) and features related to T1D (duration of T1D, adherence to treatment …). Only a few studies have searched for genetic factors influencing HbA1c level, most of which focused on candidate genes using classical genetic statistical methods, with generally limited power and incomplete adjustment for confounding factors and multiple testing. Our review shows the complexity of explaining HbA1c level variations, which involves numerous correlated predictors. Overall, our review underlines the lack of studies investigating jointly genetic and non-genetic factors and their interactions to better understand factors influencing glycaemic control for T1D patients.
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Affiliation(s)
- Emilie Gloaguen
- Inserm UMRS-958, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | | | - Marc Nicolino
- Hôpital Femme-Mère-Enfant, Hospices Civils de Lyon, Bron, France
| | - Cécile Julier
- Inserm UMRS-958, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
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Subkhangulova A, Malik AR, Hermey G, Popp O, Dittmar G, Rathjen T, Poy MN, Stumpf A, Beed PS, Schmitz D, Breiderhoff T, Willnow TE. SORCS1 and SORCS3 control energy balance and orexigenic peptide production. EMBO Rep 2018; 19:embr.201744810. [PMID: 29440124 PMCID: PMC5891432 DOI: 10.15252/embr.201744810] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 01/15/2018] [Accepted: 01/22/2018] [Indexed: 12/20/2022] Open
Abstract
SORCS1 and SORCS3 are two related sorting receptors expressed in neurons of the arcuate nucleus of the hypothalamus. Using mouse models with individual or dual receptor deficiencies, we document a previously unknown function of these receptors in central control of metabolism. Specifically, SORCS1 and SORCS3 act as intracellular trafficking receptors for tropomyosin-related kinase B to attenuate signaling by brain-derived neurotrophic factor, a potent regulator of energy homeostasis. Loss of the joint action of SORCS1 and SORCS3 in mutant mice results in excessive production of the orexigenic neuropeptide agouti-related peptide and in a state of chronic energy excess characterized by enhanced food intake, decreased locomotor activity, diminished usage of lipids as metabolic fuel, and increased adiposity, albeit at overall reduced body weight. Our findings highlight a novel concept in regulation of the melanocortin system and the role played by trafficking receptors SORCS1 and SORCS3 in this process.
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Affiliation(s)
| | - Anna R Malik
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Guido Hermey
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Oliver Popp
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Gunnar Dittmar
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Thomas Rathjen
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Matthew N Poy
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Alexander Stumpf
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | - Prateep Sanker Beed
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | - Dietmar Schmitz
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | | | - Thomas E Willnow
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany .,Berlin Institute of Health, Berlin, Germany
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Trafficking in Alzheimer's Disease: Modulation of APP Transport and Processing by the Transmembrane Proteins LRP1, SorLA, SorCS1c, Sortilin, and Calsyntenin. Mol Neurobiol 2017; 55:5809-5829. [PMID: 29079999 DOI: 10.1007/s12035-017-0806-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/17/2017] [Indexed: 12/11/2022]
Abstract
The amyloid precursor protein (APP), one key player in Alzheimer's disease (AD), is extensively processed by different proteases. This leads to the generation of diverging fragments including the amyloid β (Aβ) peptide, which accumulates in brains of AD patients. Subcellular trafficking of APP is an important aspect for its proteolytic conversion, since the various secretases which cleave APP are located in different cellular compartments. As a consequence, altered subcellular targeting of APP is thought to directly affect the degree to which Aβ is generated. The mechanisms underlying intracellular APP transport are critical to understand AD pathogenesis and can serve as a target for future pharmacological interventions. In the recent years, a number of APP interacting proteins were identified which are implicated in sorting of APP, thereby influencing APP processing at different angles of the secretory or endocytic pathway. This review provides an update on the proteolytic processing of APP and the interplay of the transmembrane proteins low-density lipoprotein receptor-related protein 1, sortilin-receptor with A-type repeats, SorCS1c, sortilin, and calsyntenin. We discuss the specific interactions with APP, the capacity to modulate the intracellular itinerary and the proteolytic conversion of APP, a possible involvement in the clearance of Aβ, and the implications of these transmembrane proteins in AD and other neurodegenerative diseases.
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10
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Ricard A, Robert C, Blouin C, Baste F, Torquet G, Morgenthaler C, Rivière J, Mach N, Mata X, Schibler L, Barrey E. Endurance Exercise Ability in the Horse: A Trait with Complex Polygenic Determinism. Front Genet 2017; 8:89. [PMID: 28702049 PMCID: PMC5488500 DOI: 10.3389/fgene.2017.00089] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/09/2017] [Indexed: 12/17/2022] Open
Abstract
Endurance horses are able to run at more than 20 km/h for 160 km (in bouts of 30-40 km). This level of performance is based on intense aerobic metabolism, effective body heat dissipation and the ability to endure painful exercise. The known heritabilities of endurance performance and exercise-related physiological traits in Arabian horses suggest that adaptation to extreme endurance exercise is influenced by genetic factors. The objective of the present genome-wide association study (GWAS) was to identify single nucleotide polymorphisms (SNPs) related to endurance racing performance in 597 Arabian horses. The performance traits studied were the total race distance, average race speed and finishing status (qualified, eliminated or retired). We used three mixed models that included a fixed allele or genotype effect and a random, polygenic effect. Quantile-quantile plots were acceptable, and the regression coefficients for actual vs. expected log10p-values ranged from 0.865 to 1.055. The GWAS revealed five significant quantitative trait loci (QTL) corresponding to 6 SNPs on chromosomes 6, 1, 7, 16, and 29 (two SNPs) with corrected p-values from 1.7 × 10-6 to 1.8 × 10-5. Annotation of these 5 QTL revealed two genes: sortilin-related VPS10-domain-containing receptor 3 (SORCS3) on chromosome 1 is involved in protein trafficking, and solute carrier family 39 member 12 (SLC39A12) on chromosome 29 is active in zinc transport and cell homeostasis. These two coding genes could be involved in neuronal tissues (CNS). The other QTL on chromosomes 6, 7, and 16 may be involved in the regulation of the gene expression through non-coding RNAs, CpG islands and transcription factor binding sites. On chromosome 6, a new candidate equine long non-coding RNA (KCNQ1OT1 ortholog: opposite antisense transcript 1 of potassium voltage-gated channel subfamily Q member 1 gene) was predicted in silico and validated by RT-qPCR in primary cultures of equine myoblasts and fibroblasts. This lncRNA could be one element of the cardiac rhythm regulation. Our GWAS revealed that equine performance during endurance races is a complex polygenic trait, and is partially governed by at least 5 QTL: two coding genes involved in neuronal tissues and three other loci with many regulatory functions such as slowing down heart rate.
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Affiliation(s)
- Anne Ricard
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
- Institut Français du Cheval et de l'Equitation, Département Recherche et InnovationExmes, France
| | - Céline Robert
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
- Ecole Nationale Vétérinaire d'AlfortMaisons Alfort, France
| | - Christine Blouin
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
| | - Fanny Baste
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
| | - Gwendoline Torquet
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
| | - Caroline Morgenthaler
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
| | - Julie Rivière
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
| | - Nuria Mach
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
| | - Xavier Mata
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
| | - Laurent Schibler
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
| | - Eric Barrey
- Institut National de la Recherche Agronomique, AgroParisTech, Université Paris Saclay, Département Sciences du Vivant, UMR 1313 Génétique Animale et Biologie IntégrativeJouy-en-Josas, France
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Eliasson L, Esguerra JLS, Wendt A. Lessons from basic pancreatic beta cell research in type-2 diabetes and vascular complications. Diabetol Int 2017; 8:139-152. [PMID: 30603317 DOI: 10.1007/s13340-017-0304-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 01/08/2017] [Indexed: 12/14/2022]
Abstract
The changes in life-style with increased access of food and reduced physical activity have resulted in the global epidemic of obesity. Consequently, individuals with type 2 diabetes and cardiovascular disease have also escalated. A central organ in the development of diabetes is the pancreas, and more specifically the pancreatic beta cells within the islets of Langerhans. Beta cells have been assigned the important task of secreting insulin when blood glucose is increased to lower the glucose level. An early sign of diabetes pathogenesis is lack of first phase insulin response and reduced second phase secretion. In this review, which is based on the foreign investigator award lecture given at the JSDC meeting in Sendai in October 2016, we discuss a possible cellular explanation for the reduced first phase insulin response and how this can be influenced by lipids. Moreover, since patients with cardiovascular disease and high levels of cholesterol are often treated with statins, we summarize recent data regarding effects on statins on glucose homeostasis and insulin secretion. Finally, we suggest microRNAs (miRNAs) as central players in the adjustment of beta cell function during the development of diabetes. We specifically discuss miRNAs regarding their involvement in insulin secretion regulation, differential expression in type 2 diabetes, and potential as biomarkers for prediction of diabetes and cardiovascular complications.
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Affiliation(s)
- Lena Eliasson
- Islet Cell Exocytosis, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Clinical Research Centre, SUS 91-11, Box 50332, 202 13 Malmö, Sweden
| | - Jonathan Lou S Esguerra
- Islet Cell Exocytosis, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Clinical Research Centre, SUS 91-11, Box 50332, 202 13 Malmö, Sweden
| | - Anna Wendt
- Islet Cell Exocytosis, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Clinical Research Centre, SUS 91-11, Box 50332, 202 13 Malmö, Sweden
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12
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Oelsner KT, Guo Y, To SBC, Non AL, Barkin SL. Maternal BMI as a predictor of methylation of obesity-related genes in saliva samples from preschool-age Hispanic children at-risk for obesity. BMC Genomics 2017; 18:57. [PMID: 28068899 PMCID: PMC5223358 DOI: 10.1186/s12864-016-3473-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 12/26/2016] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The study of epigenetic processes and mechanisms present a dynamic approach to assess complex individual variation in obesity susceptibility. However, few studies have examined epigenetic patterns in preschool-age children at-risk for obesity despite the relevance of this developmental stage to trajectories of weight gain. We hypothesized that salivary DNA methylation patterns of key obesogenic genes in Hispanic children would 1) correlate with maternal BMI and 2) allow for identification of pathways associated with children at-risk for obesity. RESULTS Genome-wide DNA methylation was conducted on 92 saliva samples collected from Hispanic preschool children using the Infinium Illumina HumanMethylation 450 K BeadChip (Illumina, San Diego, CA, USA), which interrogates >484,000 CpG sites associated with ~24,000 genes. The analysis was limited to 936 genes that have been associated with obesity in a prior GWAS Study. Child DNA methylation at 17 CpG sites was found to be significantly associated with maternal BMI, with increased methylation at 12 CpG sites and decreased methylation at 5 CpG sites. Pathway analysis revealed methylation at these sites related to homocysteine and methionine degradation as well as cysteine biosynthesis and circadian rhythm. Furthermore, eight of the 17 CpG sites reside in genes (FSTL1, SORCS2, NRF1, DLC1, PPARGC1B, CHN2, NXPH1) that have prior known associations with obesity, diabetes, and the insulin pathway. CONCLUSIONS Our study confirms that saliva is a practical human tissue to obtain in community settings and in pediatric populations. These salivary findings indicate potential epigenetic differences in Hispanic preschool children at risk for pediatric obesity. Identifying early biomarkers and understanding pathways that are epigenetically regulated during this critical stage of child development may present an opportunity for prevention or early intervention for addressing childhood obesity. TRIAL REGISTRATION The clinical trial protocol is available at ClinicalTrials.gov ( NCT01316653 ). Registered 3 March 2011.
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Affiliation(s)
- Kathryn Tully Oelsner
- College of Medicine, Medical University of South Carolina, 96 Jonathan Lucas St, Suite 601, MSC 617, Charleston, SC 29425 USA
| | - Yan Guo
- Center for Quantitative Research, School of Medicine, Vanderbilt University, 2220 Pierce Ave, 571 Preston Research Building, Nashville, TN USA
| | - Sophie Bao-Chieu To
- Department of Biological Sciences, Vanderbilt University, 1210 BSB, 465 21st Ave S, Nashville, TN USA
| | - Amy L. Non
- Department of Anthropology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 USA
| | - Shari L. Barkin
- Department of Pediatrics, Vanderbilt University School of Medicine, 2200 Children’s Way, Doctor’s Office Tower 8232, Nashville, TN 37232-9225 USA
- Pediatric Obesity Research, Diabetes Research and Training Center, Vanderbilt University School of Medicine, 2200 Children’s Way, Doctor’s Office Tower 8232, Nashville, TN 37232-9225 USA
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13
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Knight EM, Ruiz HH, Kim SH, Harte JC, Hsieh W, Glabe C, Klein WL, Attie AD, Buettner C, Ehrlich ME, Gandy S. Unexpected partial correction of metabolic and behavioral phenotypes of Alzheimer's APP/PSEN1 mice by gene targeting of diabetes/Alzheimer's-related Sorcs1. Acta Neuropathol Commun 2016; 4:16. [PMID: 26916443 PMCID: PMC4766719 DOI: 10.1186/s40478-016-0282-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/25/2016] [Indexed: 02/06/2023] Open
Abstract
Introduction Insulin resistance and type 2 diabetes mellitus (T2D) are associated with increased risk for cognitive impairment, Alzheimer’s disease (AD) and vascular dementia. SORCS1 encodes a protein-sorting molecule genetically linked to both T2D and AD. The association of SORCS1 with both AD and T2D is sexually dimorphic in humans, with both disease associations showing more robust effects in females. Based on published evidence that manipulation of the mouse genome combining multiple genes related to cerebral amyloidosis, to T2D, or both, might provide novel mouse models with exacerbated amyloid and/or diabetes phenotypes, we assessed memory, glucose homeostasis, and brain biochemistry and pathology in male and female wild-type, Sorcs1 -/-, APP/PSEN1, and Sorcs1 -/- X APP/PSEN1 mice. Results Male mice with either the APP/PSEN1 or Sorcs1 -/- genotype displayed earlier onset and persistent impairment in both learning behavior and glucose homeostasis. Unlike prior examples in the literature, the behavioral and metabolic abnormalities in male mice were not significantly exacerbated when the two disease model mice (Sorcs1 -/- models T2D; APP/PSEN1 models AD) were crossed. However, female Sorcs1 -/- X APP/PSEN1 mice exhibited worse metabolic dysfunction than Sorcs1 -/- knockout mice and worse memory than wild-type mice. The deletion of Sorcs1 from APP/PSEN1 mutant mice led to no obvious changes in brain levels of total or oligomeric amyloid-beta (Aβ) peptide. Conclusions In general, unexpectedly, there was a trend for gene targeting of Sorcs1-/- to partially mitigate, not exacerbate, the metabolic and amyloid pathologies. These results indicate that crossing AD model mice and T2D model mice may not always cause exacerbation of both the amyloidosis phenotype and the metabolic phenotype and highlight the unexpected pitfalls of creating mixed models of disease. Electronic supplementary material The online version of this article (doi:10.1186/s40478-016-0282-y) contains supplementary material, which is available to authorized users.
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14
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Schmidt V, Willnow TE. Protein sorting gone wrong – VPS10P domain receptors in cardiovascular and metabolic diseases. Atherosclerosis 2016; 245:194-9. [DOI: 10.1016/j.atherosclerosis.2015.11.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/04/2015] [Accepted: 11/23/2015] [Indexed: 01/02/2023]
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15
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Petri V, Hayman GT, Tutaj M, Smith JR, Laulederkind S, Wang SJ, Nigam R, De Pons J, Shimoyama M, Dwinell MR. Disease, Models, Variants and Altered Pathways-Journeying RGD Through the Magnifying Glass. Comput Struct Biotechnol J 2015; 14:35-48. [PMID: 27602200 PMCID: PMC4700298 DOI: 10.1016/j.csbj.2015.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/28/2015] [Accepted: 11/20/2015] [Indexed: 12/12/2022] Open
Abstract
Understanding the pathogenesis of disease is instrumental in delineating its progression mechanisms and for envisioning ways to counteract it. In the process, animal models represent invaluable tools for identifying disease-related loci and their genetic components. Amongst them, the laboratory rat is used extensively in the study of many conditions and disorders. The Rat Genome Database (RGD—http://rgd.mcw.edu) has been established to house rat genetic, genomic and phenotypic data. Since its inception, it has continually expanded the depth and breadth of its content. Currently, in addition to rat genes, QTLs and strains, RGD houses mouse and human genes and QTLs and offers pertinent associated data, acquired through manual literature curation and imported via pipelines. A collection of controlled vocabularies and ontologies is employed for the standardized extraction and provision of biological data. The vocabularies/ontologies allow the capture of disease and phenotype associations of rat strains and QTLs, as well as disease and pathway associations of rat, human and mouse genes. A suite of tools enables the retrieval, manipulation, viewing and analysis of data. Genes associated with particular conditions or with altered networks underlying disease pathways can be retrieved. Genetic variants in humans or in sequenced rat strains can be searched and compared. Lists of rat strains and species-specific genes and QTLs can be generated for selected ontology terms and then analyzed, downloaded or sent to other tools. From many entry points, data can be accessed and results retrieved. To illustrate, diabetes is used as a case study to initiate and embark upon an exploratory journey.
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Affiliation(s)
- Victoria Petri
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - G Thomas Hayman
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - Marek Tutaj
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - Jennifer R Smith
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - Stan Laulederkind
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - Shur-Jen Wang
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - Rajni Nigam
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - Jeff De Pons
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - Mary Shimoyama
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
| | - Melinda R Dwinell
- Human and Molecular Genetics Center, Medical College of Wisconsin, USA
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16
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Comparative Genome of GK and Wistar Rats Reveals Genetic Basis of Type 2 Diabetes. PLoS One 2015; 10:e0141859. [PMID: 26529237 PMCID: PMC4631338 DOI: 10.1371/journal.pone.0141859] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 10/14/2015] [Indexed: 12/12/2022] Open
Abstract
The Goto-Kakizaki (GK) rat, which has been developed by repeated inbreeding of glucose-intolerant Wistar rats, is the most widely studied rat model for Type 2 diabetes (T2D). However, the detailed genetic background of T2D phenotype in GK rats is still largely unknown. We report a survey of T2D susceptible variations based on high-quality whole genome sequencing of GK and Wistar rats, which have generated a list of GK-specific variations (228 structural variations, 2660 CNV amplification and 2834 CNV deletion, 1796 protein affecting SNVs or indels) by comparative genome analysis and identified 192 potential T2D-associated genes. The genes with variants are further refined with prior knowledge and public resource including variant polymorphism of rat strains, protein-protein interactions and differential gene expression. Finally we have identified 15 genetic mutant genes which include seven known T2D related genes (Tnfrsf1b, Scg5, Fgb, Sell, Dpp4, Icam1, and Pkd2l1) and eight high-confidence new candidate genes (Ldlr, Ccl2, Erbb3, Akr1b1, Pik3c2a, Cd5, Eef2k, and Cpd). Our result reveals that the T2D phenotype may be caused by the accumulation of multiple variations in GK rat, and that the mutated genes may affect biological functions including adipocytokine signaling, glycerolipid metabolism, PPAR signaling, T cell receptor signaling and insulin signaling pathways. We present the genomic difference between two closely related rat strains (GK and Wistar) and narrow down the scope of susceptible loci. It also requires further experimental study to understand and validate the relationship between our candidate variants and T2D phenotype. Our findings highlight the importance of sequenced-based comparative genomics for investigating disease susceptibility loci in inbreeding animal models.
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17
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Abstract
The genetic basis of type 2 diabetes remains incompletely defined despite the use of multiple genetic strategies. Multiparental populations such as heterogeneous stocks (HS) facilitate gene discovery by allowing fine mapping to only a few megabases, significantly decreasing the number of potential candidate genes compared to traditional mapping strategies. In the present work, we employed expression and sequence analysis in HS rats (Rattus norvegicus) to identify Tpcn2 as a likely causal gene underlying a 3.1-Mb locus for glucose and insulin levels. Global gene expression analysis on liver identified Tpcn2 as the only gene in the region that is differentially expressed between HS rats with glucose intolerance and those with normal glucose regulation. Tpcn2 also maps as a cis-regulating expression QTL and is negatively correlated with fasting glucose levels. We used founder sequence to identify variants within this region and assessed association between 18 variants and diabetic traits by conducting a mixed-model analysis, accounting for the complex family structure of the HS. We found that two variants were significantly associated with fasting glucose levels, including a nonsynonymous coding variant within Tpcn2. Studies in Tpcn2 knockout mice demonstrated a significant decrease in fasting glucose levels and insulin response to a glucose challenge relative to those in wild-type mice. Finally, we identified variants within Tpcn2 that are associated with fasting insulin in humans. These studies indicate that Tpcn2 is a likely causal gene that may play a role in human diabetes and demonstrate the utility of multiparental populations for positionally cloning genes within complex loci.
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The role of the retromer complex in aging-related neurodegeneration: a molecular and genomic review. Mol Genet Genomics 2014; 290:413-27. [PMID: 25332075 DOI: 10.1007/s00438-014-0939-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 10/10/2014] [Indexed: 10/24/2022]
Abstract
The retromer coat complex is a vital component of the intracellular trafficking mechanism sorting cargo from the endosomes to the trans-Golgi network or to the cell surface. In recent years, genes encoding components of the retromer coat complex and members of the vacuolar protein sorting 10 (Vps10) family of receptors, which play pleiotropic functions in protein trafficking and intracellular/intercellular signaling in neuronal and non-neuronal cells and are primary cargos of the retromer complex, have been implicated as genetic risk factors for sporadic and autosomal dominant forms of several neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and frontotemporal lobar degeneration. In addition to their functions in protein trafficking, the members of the Vps10 receptor family (sortilin, SorL1, SorCS1, SorCS2, and SorCS3) modulate neurotrophic signaling pathways. Both sortilin and SorCS2 act as cell surface receptors to mediate acute responses to proneurotrophins. In addition, sortilin can modulate the intracellular response to brain-derived neurotrophic factor (BDNF) by direct control of BDNF levels and regulating anterograde trafficking of Trk receptors to the synapse. This review article summarizes the emerging data from this rapidly growing field of intracellular trafficking signaling in the pathogenesis of neurodegeneration.
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19
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Kebede MA, Attie AD. Insights into obesity and diabetes at the intersection of mouse and human genetics. Trends Endocrinol Metab 2014; 25:493-501. [PMID: 25034129 PMCID: PMC4177963 DOI: 10.1016/j.tem.2014.06.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 06/06/2014] [Accepted: 06/06/2014] [Indexed: 11/25/2022]
Abstract
Many of our insights into obesity and diabetes come from studies in mice carrying natural or induced mutations. In parallel, genome-wide association studies (GWAS) in humans have identified numerous genes that are causally associated with obesity and diabetes, but discovering the underlying mechanisms required in-depth studies in mice. We discuss the advantages of studying natural variation in mice and summarize several examples where the combination of human and mouse genetics opened windows into fundamental physiological pathways. A noteworthy example is the melanocortin-4 receptor (MC4R) and its role in energy balance. The pathway was delineated by discovering the gene responsible for the Agouti mutation in mice. With more targeted phenotyping, we predict that additional pathways relevant to human pathophysiology will be discovered.
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Affiliation(s)
- Melkam A Kebede
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Alan D Attie
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Fine mapping reveals that promotion susceptibility locus 1 (Psl1) is a compound locus with multiple genes that modify susceptibility to skin tumor development. G3-GENES GENOMES GENETICS 2014; 4:1071-9. [PMID: 24700353 PMCID: PMC4065250 DOI: 10.1534/g3.113.009688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although it is well known that the majority of human cancers occur as the result of exposure to environmental carcinogens, it is clear that not all individuals exposed to a specific environmental carcinogen have the same risk of developing cancer. Considerable evidence indicates that common allelic variants of low-penetrance, tumor susceptibility genes are responsible for this interindividual variation in risk. We previously reported a skin tumor promotion susceptibility locus, Psl1, which maps to the distal portion of chromosome 9, that modified skin tumor promotion susceptibility in the mouse. Furthermore, Psl1 was shown to consist of at least two subloci (i.e., Psl1.1 and Psl1.2) and that glutathione S-transferase alpha 4 (Gsta4), which maps to Psl1.2, is a skin tumor promotion susceptibility gene. Finally, variants of human GSTA4 were found to be associated with risk of nonmelanoma skin cancer. In the current study, a combination of nested and contiguous C57BL/6 congenic mouse strains, each inheriting a different portion of the Psl1 locus from DBA/2, were tested for susceptibility to skin tumor promotion with 12-O-tetradecanoylphorbol-13-acetate. These analyses indicate that Psl1 is a compound locus with at least six genes, including Gsta4, that modify skin tumor promotion susceptibility. More than 550 protein-coding genes map within the Psl1 locus. Fine mapping of the Psl1 locus, along with two-strain haplotype analysis, gene expression analysis, and the identification of genes with amino acid variants, has produced a list of fewer than 25 candidate skin tumor promotion susceptibility genes.
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Linkage relationships among multiple QTL for horticultural traits and late blight (P. infestans) resistance on chromosome 5 introgressed from wild tomato Solanum habrochaites. G3-GENES GENOMES GENETICS 2013; 3:2131-46. [PMID: 24122052 PMCID: PMC3852376 DOI: 10.1534/g3.113.007195] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
When the allele of a wild species at a quantitative trait locus (QTL) conferring a desirable trait is introduced into cultivated species, undesirable effects on other traits may occur. These negative phenotypic effects may result from the presence of wild alleles at other closely linked loci that are transferred along with the desired QTL allele (i.e., linkage drag) and/or from pleiotropic effects of the desired allele. Previously, a QTL for resistance to Phytophthora infestans on chromosome 5 of Solanum habrochaites was mapped and introgressed into cultivated tomato (S. lycopersicum). Near-isogenic lines (NILs) were generated and used for fine-mapping of this resistance QTL, which revealed coincident or linked QTL with undesirable effects on yield, maturity, fruit size, and plant architecture traits. Subsequent higher-resolution mapping with chromosome 5 sub-NILs revealed the presence of multiple P. infestans resistance QTL within this 12.3 cM region. In our present study, these sub-NILs were also evaluated for 17 horticultural traits, including yield, maturity, fruit size and shape, fruit quality, and plant architecture traits in replicated field experiments over the course of two years. Each previously detected single horticultural trait QTL fractionated into two or more QTL. A total of 41 QTL were detected across all traits, with ∼30% exhibiting significant QTL × environment interactions. Colocation of QTL for multiple traits suggests either pleiotropy or tightly linked genes control these traits. The complex genetic architecture of horticultural and P. infestans resistance trait QTL within this S. habrochaites region of chromosome 5 presents challenges and opportunities for breeding efforts in cultivated tomato.
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Lazar J, O'Meara CC, Sarkis AB, Prisco SZ, Xu H, Fox CS, Chen MH, Broeckel U, Arnett DK, Moreno C, Provoost AP, Jacob HJ. SORCS1 contributes to the development of renal disease in rats and humans. Physiol Genomics 2013; 45:720-8. [PMID: 23780848 PMCID: PMC3742914 DOI: 10.1152/physiolgenomics.00089.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 06/14/2013] [Indexed: 12/14/2022] Open
Abstract
Many lines of evidence demonstrate that genetic variability contributes to chronic kidney disease susceptibility in humans as well as rodent models. Little progress has been made in discovering causal kidney disease genes in humans mainly due to genetic complexity. Here, we use a minimal congenic mapping strategy in the FHH (fawn hooded hypertensive) rat to identify Sorcs1 as a novel renal disease candidate gene. We investigated the hypothesis that genetic variation in Sorcs1 influences renal disease susceptibility in both rat and human. Sorcs1 is expressed in the kidney, and knocking out this gene in a rat strain with a sensitized genome background produced increased proteinuria. In vitro knockdown of Sorcs1 in proximal tubule cells impaired protein trafficking, suggesting a mechanism for the observed proteinuria in the FHH rat. Since Sorcs1 influences renal function in the rat, we went on to test this gene in humans. We identified associations between single nucleotide polymorphisms in SORCS1 and renal function in large cohorts of European and African ancestry. The experimental data from the rat combined with association results from different ethnic groups indicates a role for SORCS1 in maintaining proper renal function.
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Affiliation(s)
- Jozef Lazar
- Department of Dermatology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Vps10 family proteins and the retromer complex in aging-related neurodegeneration and diabetes. J Neurosci 2013; 32:14080-6. [PMID: 23055476 DOI: 10.1523/jneurosci.3359-12.2012] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Members of the vacuolar protein sorting 10 (Vps10) family of receptors (including sortilin, SorL1, SorCS1, SorCS2, and SorCS3) play pleiotropic functions in protein trafficking and intracellular and intercellular signaling in neuronal and non-neuronal cells. Interactions have been documented between Vps10 family members and the retromer coat complex, a key component of the intracellular trafficking apparatus that sorts cargo from the early endosome to the trans-Golgi network. In recent years, genes encoding several members of the Vps10 family of proteins, as well as components of the retromer coat complex, have been implicated as genetic risk factors for sporadic and autosomal dominant forms of neurodegenerative diseases, including Alzheimer's disease, frontotemporal lobar degeneration, and Parkinson's disease, with risk for type 2 diabetes mellitus and atherosclerosis. In addition to their functions in protein trafficking, the Vps10 family proteins modulate neurotrophic signaling pathways. Sortilin can impact the intracellular response to brain-derived neurotrophic factor (BDNF) by regulating anterograde trafficking of Trk receptors to the synapse and direct control of BDNF levels, while both sortilin and SorCS2 function as cell surface receptors to mediate acute responses to proneurotrophins. This mini-review and symposium will highlight the emerging data from this rapidly growing area of research implicating the Vps10 family of receptors and the retromer in physiological intracellular trafficking signaling by neurotrophins and in the pathogenesis of neurodegeneration.
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He Y, Fang Z, Yu G. Sortilin-related VPS10 domain containing receptor 1 and Alzheimer's disease-associated allelic variations preferentially exist in female or type 2 diabetes mellitus patients in southern Han Chinese. Psychogeriatrics 2012; 12:215-25. [PMID: 23279143 DOI: 10.1111/j.1479-8301.2012.00405.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Both in vitro and in vivo, overexpression of the sortilin-related VPS10 domain containing receptor 1 (SORCS1) protein lowers amyloid-β generation. Recent studies have shown that SORCS1 variations in intron 1 are associated with sporadic Alzheimer's disease (SAD), but the results remain inconsistent. METHODS In order to clarify the role of the SORCS1 gene in southern Han Chinese, we genotyped eight single nucleotide polymorphisms (SNP) of SORCS1 in 128 SAD patients and 92 healthy controls. RESULTS By dividing patients and controls according to apolipoprotein status, sex and whether they had type 2 diabetes mellitus, we found that rs7907690 C allele frequencies were significantly higher in the Alzheimer's disease (AD) patients with type 2 diabetes mellitus than in the controls (P=0.041). Also, the rs600879 GG genotype and G allele worked as protective factors of SAD in women (GG genotype, P=0.007; G allele, P=0.009). In multilocus analysis, the frequency of an eight-single nucleotide polymorphism rs601883/rs7907690/rs600879/rs17277986/rs2900717/rs10884399/rs11193170/rs4918280 CCGGACGG haplotype was significantly higher in AD patients (6.3%), especially in female AD patients (9.5%), than in the controls (0.5%) (P=0.003; P=0.0002). However, the CTGGACGG haplotype was significantly lower in AD patients (9.3%) than in controls (20.3%) (P=0.001). The association remained significant even after Bonferroni correction for the number of haplotypes. CONCLUSION This study provides evidence that variations in the SORCS1 gene influence susceptibility to SAD in southern Han Chinese. The genetic link between AD and SORCS1 gene variations are influenced by ethnic background, sex and whether an individual has type 2 diabetes mellitus.
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Affiliation(s)
- Yanqin He
- Department of Geriatrics, the Second Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, Nanjing, China
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Solberg Woods LC, Holl KL, Oreper D, Xie Y, Tsaih SW, Valdar W. Fine-mapping diabetes-related traits, including insulin resistance, in heterogeneous stock rats. Physiol Genomics 2012; 44:1013-26. [PMID: 22947656 DOI: 10.1152/physiolgenomics.00040.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Type 2 diabetes (T2D) is a disease of relative insulin deficiency resulting from both insulin resistance and beta cell failure. We have previously used heterogeneous stock (HS) rats to fine-map a locus for glucose tolerance. We show here that glucose intolerance in the founder strains of the HS colony is mediated by different mechanisms: insulin resistance in WKY and an insulin secretion defect in ACI, and we demonstrate a high degree of variability for measures of insulin resistance and insulin secretion in HS rats. As such, our goal was to use HS rats to fine-map several diabetes-related traits within a region on rat chromosome 1. We measured blood glucose and plasma insulin levels after a glucose tolerance test in 782 male HS rats. Using 97 SSLP markers, we genotyped a 68 Mb region on rat chromosome 1 previously implicated in glucose and insulin regulation. We used linkage disequilibrium mapping by mixed model regression with inferred descent to identify a region from 198.85 to 205.9 that contains one or more quantitative trait loci (QTL) for fasting insulin and a measure of insulin resistance, the quantitative insulin sensitivity check index. This region also encompasses loci identified for fasting glucose and Insulin_AUC (area under the curve). A separate <3 Mb QTL was identified for body weight. Using a novel penalized regression method we then estimated effects of alternative haplotype pairings under each locus. These studies highlight the utility of HS rats for fine-mapping genetic loci involved in the underlying causes of T2D.
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Affiliation(s)
- Leah C Solberg Woods
- Department of Pediatrics, Human and Molecular Genetics Center and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Reitz C. The role of intracellular trafficking and the VPS10d receptors in Alzheimer's disease. FUTURE NEUROLOGY 2012; 7:423-431. [PMID: 23264752 DOI: 10.2217/fnl.12.31] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In Alzheimer's disease, the key pathological culprit is the amyloid-β protein, which is generated through β- and γ-secretase cleavage of the amyloid-β precursor protein (APP). Both the secretases and amyloid-β precursor protein are transmembrane proteins that are sorted via the trans-Golgi network and the endosome through multiple membranous compartments of the cell. The coat complex clathrin controls the sorting from the cell surface and the trans-Golgi network to the endosome. Instead, the retromer controls the reverse transport from the endosome to the trans-Golgi network. The retromer contains two subprotein complexes: the cargo-selective subcomplex consisting of VPS35, VPS29 and VPS26 and the membrane deformation subcomplex consisting of Vps5p, Vps17p, SNX 1/2 and possibly SNX 5/6 or SNX 32 in mammals. Cargo molecules of the retromer include the VPS10 receptor proteins SORL1, SORT1, SORCS1, SORCS2 and SORCS3. There is increasing evidence through cell biology and animal and genetic studies that components of the retromer and the VPS10d receptor family play a role in the etiology of Alzheimer's disease. This article reviews and summarizes this current evidence.
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Affiliation(s)
- Christiane Reitz
- The Taub Institute for Research on Alzheimer's Disease & the Aging Brain, The Gertrude H. Sergievsky Center, Columbia University, 630 W 168th Street, New York, NY 10032, USA ; The Department of Neurology, College of Physicians & Surgeons, Columbia University, 630 W 168th Street, New York, NY 10032, USA
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Does Familial Clustering of Risk Factors for Long-Term Diabetic Complications Leave Any Place for Genes That Act independently? J Cardiovasc Transl Res 2012; 5:388-98. [DOI: 10.1007/s12265-012-9385-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 05/30/2012] [Indexed: 10/28/2022]
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Olgiati P, Politis AM, Papadimitriou GN, De Ronchi D, Serretti A. Genetics of late-onset Alzheimer's disease: update from the alzgene database and analysis of shared pathways. Int J Alzheimers Dis 2011; 2011:832379. [PMID: 22191060 PMCID: PMC3235576 DOI: 10.4061/2011/832379] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 09/21/2011] [Indexed: 12/13/2022] Open
Abstract
The genetics of late-onset Alzheimer's disease (LOAD) has taken impressive steps forwards in the last few years. To date, more than six-hundred genes have been linked to the disorder. However, only a minority of them are supported by a sufficient level of evidence. This review focused on such genes and analyzed shared biological pathways. Genetic markers were selected from a web-based collection (Alzgene). For each SNP in the database, it was possible to perform a meta-analysis. The quality of studies was assessed using criteria such as size of research samples, heterogeneity across studies, and protection from publication bias. This produced a list of 15 top-rated genes: APOE, CLU, PICALM, EXOC3L2, BIN1, CR1, SORL1, TNK1, IL8, LDLR, CST3, CHRNB2, SORCS1, TNF, and CCR2. A systematic analysis of gene ontology terms associated with each marker showed that most genes were implicated in cholesterol metabolism, intracellular transport of beta-amyloid precursor, and autophagy of damaged organelles. Moreover, the impact of these genes on complement cascade and cytokine production highlights the role of inflammatory response in AD pathogenesis. Gene-gene and gene-environment interactions are prominent issues in AD genetics, but they are not specifically featured in the Alzgene database.
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Affiliation(s)
- Paolo Olgiati
- Institute of Psychiatry, University of Bologna, Viale Carlo Pepoli 5, 40123 Bologna, Italy
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Ohsakaya S, Fujikawa M, Hisabori T, Yoshida M. Knockdown of DAPIT (diabetes-associated protein in insulin-sensitive tissue) results in loss of ATP synthase in mitochondria. J Biol Chem 2011; 286:20292-6. [PMID: 21345788 DOI: 10.1074/jbc.m110.198523] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It was found recently that a diabetes-associated protein in insulin-sensitive tissue (DAPIT) is associated with mitochondrial ATP synthase. Here, we report that the suppressed expression of DAPIT in DAPIT-knockdown HeLa cells causes loss of the population of ATP synthase in mitochondria. Consequently, DAPIT-knockdown cells show smaller mitochondrial ATP synthesis activity, slower growth in normal medium, and poorer viability in glucose-free medium than the control cells. The mRNA levels of α- and β-subunits of ATP synthase remain unchanged by DAPIT knockdown. These results indicate a critical role of DAPIT in maintaining the ATP synthase population in mitochondria and raise an intriguing possibility of active role of DAPIT in cellular energy metabolism.
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Affiliation(s)
- Shigenori Ohsakaya
- International Cooperative Research Project ATP-Synthesis Regulation Project, Japan Science and Technology Agency, 2-3-6 Aomi, Koto-Ku, Tokyo 135-0064, Japan
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Hertel JK, Johansson S, Ræder H, Platou CGP, Midthjell K, Hveem K, Molven A, Njølstad PR. Evaluation of four novel genetic variants affecting hemoglobin A1c levels in a population-based type 2 diabetes cohort (the HUNT2 study). BMC MEDICAL GENETICS 2011; 12:20. [PMID: 21294870 PMCID: PMC3044669 DOI: 10.1186/1471-2350-12-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 02/04/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND Chronic hyperglycemia confers increased risk for long-term diabetes-associated complications and repeated hemoglobin A1c (HbA1c) measures are a widely used marker for glycemic control in diabetes treatment and follow-up. A recent genome-wide association study revealed four genetic loci, which were associated with HbA1c levels in adults with type 1 diabetes. We aimed to evaluate the effect of these loci on glycemic control in type 2 diabetes. METHODS We genotyped 1,486 subjects with type 2 diabetes from a Norwegian population-based cohort (HUNT2) for single-nucleotide polymorphisms (SNPs) located near the BNC2, SORCS1, GSC and WDR72 loci. Through regression models, we examined their effects on HbA1c and non-fasting glucose levels individually and in a combined genetic score model. RESULTS No significant associations with HbA1c or glucose levels were found for the SORCS1, BNC2, GSC or WDR72 variants (all P-values > 0.05). Although the observed effects were non-significant and of much smaller magnitude than previously reported in type 1 diabetes, the SORCS1 risk variant showed a direction consistent with increased HbA1c and glucose levels, with an observed effect of 0.11% (P = 0.13) and 0.13 mmol/l (P = 0.43) increase per risk allele for HbA1c and glucose, respectively. In contrast, the WDR72 risk variant showed a borderline association with reduced HbA1c levels (β = -0.21, P = 0.06), and direction consistent with decreased glucose levels (β = -0.29, P = 0.29). The allele count model gave no evidence for a relationship between increasing number of risk alleles and increasing HbA1c levels (β = 0.04, P = 0.38). CONCLUSIONS The four recently reported SNPs affecting glycemic control in type 1 diabetes had no apparent effect on HbA1c in type 2 diabetes individually or by using a combined genetic score model. However, for the SORCS1 SNP, our findings do not rule out a possible relationship with HbA1c levels. Hence, further studies in other populations are needed to elucidate whether these novel sequence variants, especially rs1358030 near the SORCS1 locus, affect glycemic control in type 2 diabetes.
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Affiliation(s)
- Jens K Hertel
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
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Lagerholm S, Park HB, Luthman H, Nilsson M, McGuigan F, Swanberg M, Akesson K. Genetic loci for bone architecture determined by three-dimensional CT in crosses with the diabetic GK rat. Bone 2010; 47:1039-47. [PMID: 20699128 DOI: 10.1016/j.bone.2010.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 07/30/2010] [Accepted: 08/04/2010] [Indexed: 10/19/2022]
Abstract
The F344 rat carries alleles contributing to bone fragility while the GK rat spontaneously develops type-2 diabetes. These characteristics make F344×GK crosses well suited for the identification of genes related to bone size and allow for future investigation on the association with type-2 diabetes. The aim of this study was to identify quantitative trait loci (QTLs) for bone size phenotypes measured by a new application of three-dimensional computed tomography (3DCT) and to investigate the effects of sex- and reciprocal cross. Tibia from male and female GK and F344 rats, representing the parental, F1 and F2 generations, were examined with 3DCT and analyzed for: total and cortical volumetric BMD, straight and curved length, peri- and endosteal area at mid-shaft. F2 progeny (108 male and 98 female) were genotyped with 192 genome-wide microsatellite markers (average distance 10 cM). Sex- and reciprocal cross-separated QTL analyses were performed for the identification of QTLs linked to 3DCT phenotypes and true interactions were confirmed by likelihood ratio analysis in all F2 animals. Several genome-wide significant QTLs were found in the sex- and reciprocal cross-separated progeny on chromosomes (chr) 1, 3, 4, 9, 10, 14, and 17. Overlapping QTLs for both males and females in the (GK×F344)F2 progeny were located on chr 1 (39-67 cM). This region confirms previously reported pQCT QTLs and overlaps loci for fasting glucose. Sex separated linkage analysis confirmed a male specific QTL on chr 9 (67-82 cM) for endosteal area at the fibula site. Analyses separating the F2 population both by sex and reciprocal cross identified cross specific QTLs on chr 14 (males) and chr 3 and 4 (females). Two loci, chr 4 and 6, are unique to 3DCT and separate from pQCT generated loci. The 3DCT method was highly reproducible and provided high precision measurements of bone size in the rat enabling identification of new sex- and cross-specific loci. The QTLs on chr 1 indicate potential genetic association between bone-related phenotypes and traits affecting type-2 diabetes. The results illustrate the complexity of the genetic architecture of bone size phenotypes and demonstrate the importance of complementary methods for bone analysis.
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Affiliation(s)
- Sofia Lagerholm
- Lund University, Department of Clinical Sciences-Malmö, Clinical and Molecular Osteoporosis Unit, Malmö, Sweden.
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Analyses of copy number variation of GK rat reveal new putative type 2 diabetes susceptibility loci. PLoS One 2010; 5:e14077. [PMID: 21124896 PMCID: PMC2990713 DOI: 10.1371/journal.pone.0014077] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 10/31/2010] [Indexed: 01/15/2023] Open
Abstract
Large efforts have been taken to search for genes responsible for type 2 diabetes (T2D), but have resulted in only about 20 in humans due to its complexity and heterogeneity. The GK rat, a spontanous T2D model, offers us a superior opportunity to search for more diabetic genes. Utilizing array comparative genome hybridization (aCGH) technology, we identifed 137 non-redundant copy number variation (CNV) regions from the GK rats when using normal Wistar rats as control. These CNV regions (CNVRs) covered approximately 36 Mb nucleotides, accounting for about 1% of the whole genome. By integrating information from gene annotations and disease knowledge, we investigated the CNVRs comprehensively for mining new T2D genes. As a result, we prioritized 16 putative protein-coding genes and two microRNA genes (rno-mir-30b and rno-mir-30d) as good candidates. The catalogue of CNVRs between GK and Wistar rats identified in this work served as a repository for mining genes that might play roles in the pathogenesis of T2D. Moreover, our efforts in utilizing bioinformatics methods to prioritize good candidate genes provided a more specific set of putative candidates. These findings would contribute to the research into the genetic basis of T2D, and thus shed light on its pathogenesis.
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Diabetes-associated SorCS1 regulates Alzheimer's amyloid-beta metabolism: evidence for involvement of SorL1 and the retromer complex. J Neurosci 2010; 30:13110-5. [PMID: 20881129 DOI: 10.1523/jneurosci.3872-10.2010] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SorCS1 and SorL1/SorLA/LR11 belong to the sortilin family of vacuolar protein sorting-10 (Vps10) domain-containing proteins. Both are genetically associated with Alzheimer's disease (AD), and SORL1 expression is decreased in the brains of patients suffering from AD. SORCS1 is also genetically associated with types 1 and 2 diabetes mellitus (T1DM, T2DM). We have undertaken a study of the possible role(s) for SorCS1 in metabolism of the Alzheimer's amyloid-β peptide (Aβ) and the Aβ precursor protein (APP), to test the hypothesis that Sorcs1 deficiency might be a common genetic risk factor underlying the predisposition to AD that is associated with T2DM. Overexpression of SorCS1cβ-myc in cultured cells caused a reduction (p = 0.002) in Aβ generation. Conversely, endogenous murine Aβ(40) and Aβ(42) levels were increased (Aβ(40), p = 0.044; Aβ(42), p = 0.007) in the brains of female Sorcs1 hypomorphic mice, possibly paralleling the sexual dimorphism that is characteristic of the genetic associations of SORCS1 with AD and DM. Since SorL1 directly interacts with Vps35 to modulate APP metabolism, we investigated the possibility that SorCS1cβ-myc interacts with APP, SorL1, and/or Vps35. We readily recovered SorCS1:APP, SorCS1:SorL1, and SorCS1:Vps35 complexes from nontransgenic mouse brain. Notably, total Vps35 protein levels were decreased by 49% (p = 0.009) and total SorL1 protein levels were decreased by 29% (p = 0.003) in the brains of female Sorcs1 hypomorphic mice. From these data, we propose that dysfunction of SorCS1 may contribute to both the APP/Aβ disturbance underlying AD and the insulin/glucose disturbance underlying DM.
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Affiliation(s)
- Jose C Florez
- Massachusetts General Hospital/Harvard Medical School, Center for Human Genetic Research and Diabetes Research Center (Diabetes Unit), Boston, Massachusetts, USA.
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35
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Paterson AD, Waggott D, Boright AP, Hosseini SM, Shen E, Sylvestre MP, Wong I, Bharaj B, Cleary PA, Lachin JM, Below JE, Nicolae D, Cox NJ, Canty AJ, Sun L, Bull SB. A genome-wide association study identifies a novel major locus for glycemic control in type 1 diabetes, as measured by both A1C and glucose. Diabetes 2010; 59:539-49. [PMID: 19875614 PMCID: PMC2809960 DOI: 10.2337/db09-0653] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Glycemia is a major risk factor for the development of long-term complications in type 1 diabetes; however, no specific genetic loci have been identified for glycemic control in individuals with type 1 diabetes. To identify such loci in type 1 diabetes, we analyzed longitudinal repeated measures of A1C from the Diabetes Control and Complications Trial. RESEARCH DESIGN AND METHODS We performed a genome-wide association study using the mean of quarterly A1C values measured over 6.5 years, separately in the conventional (n = 667) and intensive (n = 637) treatment groups of the DCCT. At loci of interest, linear mixed models were used to take advantage of all the repeated measures. We then assessed the association of these loci with capillary glucose and repeated measures of multiple complications of diabetes. RESULTS We identified a major locus for A1C levels in the conventional treatment group near SORCS1 (10q25.1, P = 7 x 10(-10)), which was also associated with mean glucose (P = 2 x 10(-5)). This was confirmed using A1C in the intensive treatment group (P = 0.01). Other loci achieved evidence close to genome-wide significance: 14q32.13 (GSC) and 9p22 (BNC2) in the combined treatment groups and 15q21.3 (WDR72) in the intensive group. Further, these loci gave evidence for association with diabetic complications, specifically SORCS1 with hypoglycemia and BNC2 with renal and retinal complications. We replicated the SORCS1 association in Genetics of Diabetes in Kidneys (GoKinD) study control subjects (P = 0.01) and the BNC2 association with A1C in nondiabetic individuals. CONCLUSIONS A major locus for A1C and glucose in individuals with diabetes is near SORCS1. This may influence the design and analysis of genetic studies attempting to identify risk factors for long-term diabetic complications.
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Affiliation(s)
- Andrew D Paterson
- Program in Genetics and Genome Biology, Hospital for Sick Children, Toronto, Canada.
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Solberg Woods LC, Holl K, Tschannen M, Valdar W. Fine-mapping a locus for glucose tolerance using heterogeneous stock rats. Physiol Genomics 2010; 41:102-8. [PMID: 20068026 DOI: 10.1152/physiolgenomics.00178.2009] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Heterogeneous stock (HS) animals provide the ability to map quantitative trait loci at high resolution [<5 Megabase (Mb)] in a relatively short time period. In the current study, we hypothesized that the HS rat colony would be useful for fine-mapping a region on rat chromosome 1 that has previously been implicated in glucose regulation. We administered a glucose tolerance test to 515 HS rats and genotyped these animals with 69 microsatellite markers, spaced an average distance of <1 Mb apart, on a 67 Mb region of rat chromosome 1. Using regression modeling of inferred haplotypes based on a hidden Markov model reconstruction and mixed model analysis in which we accounted for the complex family structure of the HS, we identified one sharp peak within this region. Using positional bootstrapping, we determined the most likely location of this locus is from 205.04 to 207.48 Mb. This work demonstrates the utility of HS rats for fine-mapping complex traits and emphasizes the importance of taking into account family structure when using highly recombinant populations.
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Affiliation(s)
- Leah C Solberg Woods
- Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Solberg Woods LC, Ahmadiyeh N, Baum A, Shimomura K, Li Q, Steiner DF, Turek FW, Takahashi JS, Churchill GA, Redei EE. Identification of genetic loci involved in diabetes using a rat model of depression. Mamm Genome 2009; 20:486-97. [PMID: 19697080 DOI: 10.1007/s00335-009-9211-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Accepted: 07/22/2009] [Indexed: 11/29/2022]
Abstract
While diabetic patients often present with comorbid depression, the underlying mechanisms linking diabetes and depression are unknown. The Wistar Kyoto (WKY) rat is a well-known animal model of depression and stress hyperreactivity. In addition, the WKY rat is glucose intolerant and likely harbors diabetes susceptibility alleles. We conducted a quantitative trait loci (QTL) analysis in the segregating F(2) population of a WKY x Fischer 344 (F344) intercross. We previously published QTL analyses for depressive behavior and hypothalamic-pituitary-adrenal (HPA) activity in this cross. In this study we report results from the QTL analysis for multiple metabolic phenotypes, including fasting glucose, post-restraint stress glucose, postprandial glucose and insulin, and body weight. We identified multiple QTLs for each trait and many of the QTLs overlap with those previously identified using inbred models of type 2 diabetes (T2D). Significant correlations were found between metabolic traits and HPA axis measures, as well as forced swim test behavior. Several metabolic loci overlap with loci previously identified for HPA activity and forced swim behavior in this F(2) intercross, suggesting that the genetic mechanisms underlying these traits may be similar. These results indicate that WKY rats harbor diabetes susceptibility alleles and suggest that this strain may be useful for dissecting the underlying genetic mechanisms linking diabetes, HPA activity, and depression.
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Affiliation(s)
- Leah C Solberg Woods
- Department of Psychiatry and Behavioral Science, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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Hermey G. The Vps10p-domain receptor family. Cell Mol Life Sci 2009; 66:2677-89. [PMID: 19434368 PMCID: PMC11115710 DOI: 10.1007/s00018-009-0043-1] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 04/21/2009] [Accepted: 04/21/2009] [Indexed: 12/24/2022]
Abstract
The family of mammalian type-I transmembrane receptors containing a Vps10p domain contains five members, Sortilin, SorCS1, SorCS2, SorCS3, and SorLA. The common characteristic of these receptors is an N-terminal Vps10p domain, which either represents the only module of the luminal/extracellular moiety or is combined with additional domains. Family members play roles in protein transport and signal transduction. The individual receptors bind and internalize a variety of ligands, such as neuropeptides and trophic factors, and Sortilin and SorLA mediate trans-Golgi network-to-endosome sorting. Their prominent neuronal expression, several of the identified ligands, and recent results support the notion that members of this receptor family have important functions in neurogenesis, plasticity-related processes, and functional maintenance of the nervous system. For instance, it has been demonstrated that Sortilin partakes in the transduction of proapoptotic effects, and there is converging biochemical and genetic evidence that implies that SorLA is an Alzheimer's disease risk factor.
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Affiliation(s)
- Guido Hermey
- Institute of Molecular and Cellular Cognition, Zentrum für Molekulare Neurobiologie Hamburg, Hamburg, Germany.
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Nobrega MA, Solberg Woods LC, Fleming S, Jacob HJ. Distinct genetic regulation of progression of diabetes and renal disease in the Goto-Kakizaki rat. Physiol Genomics 2009; 39:38-46. [PMID: 19584172 DOI: 10.1152/physiolgenomics.90389.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Goto-Kakizaki (GK) rats develop early-onset type 2 diabetes (T2D) symptoms, with signs of diabetic nephropathy becoming apparent with aging. To determine whether T2D and renal disease share similar genetic architecture, we ran a quantitative trait locus (QTL) analysis in the F2 progeny of a GK x Brown Norway (BN) rat cross. Further, to determine whether genetic components change over time, we ran the QTL analysis on phenotypes collected longitudinally, at 3, 6, 9 and 12 mo, from the same animals. We confirmed three chromosomal regions that are linked to early diabetes phenotypes (chromosomes 1, 5, and 10) and a single region involved in the late progression of the disorder (chromosome 4). A single region was identified for the onset of the renal phenotype proteinuria (chromosome 5). This region overlaps the diabetic QTL, although it is not certain whether similar genes are involved in both phenotypes. A second QTL linked to the progression of the renal phenotype was found on chromosome 7. Linkage for triglyceride and cholesterol levels were also identified (chromosomes 7 and 8, respectively). These results demonstrate that, in general, different genetic components control diabetic and renal phenotypes in a diabetic nephropathy model. Furthermore, these results demonstrate that, over time, different genetic components are involved in progression of disease from those that were involved in disease onset. This observation would suggest that clinical studies collecting participants over a wide age distribution may be diluting genetic effects and reducing power to detect true effects.
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Affiliation(s)
- Marcelo A Nobrega
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53266, USA.
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VPS10P-domain receptors — regulators of neuronal viability and function. Nat Rev Neurosci 2008; 9:899-909. [DOI: 10.1038/nrn2516] [Citation(s) in RCA: 189] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Gulcher J, Stefansson K. The clinical utility of genetic risk variants in type 2 diabetes. EXPERT OPINION ON MEDICAL DIAGNOSTICS 2008; 2:991-1002. [PMID: 23495871 DOI: 10.1517/17530059.2.8.991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Type 2 diabetes is one of the first success stories in the application of genome-wide linkage and association studies to find genetic variants contributing to its risk. OBJECTIVE Are the genetic markers found so far useful in predicting which individuals are more likely to develop type 2 diabetes? Can they find which patients with prediabetes are more likely to convert to type 2 diabetes and therefore may benefit the most from lifestyle or pharmacologic prevention strategies? METHODS The literature pertaining to the discovery and replications of genes contributing to type 2 diabetes was focused on. RESULTS/CONCLUSION Substantial risk for type 2 diabetes is represented by the top 8 genes, including TCF7L2, and in certain circumstances may be useful for prevention strategies targeted to those with highest risk.
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Affiliation(s)
- Jeff Gulcher
- Decode Genetics, Inc., Sturlugata 8, 101 Reykjavik, Iceland
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Hasstedt SJ, Chu WS, Das SK, Wang H, Elbein SC. Type 2 diabetes susceptibility genes on chromosome 1q21-24. Ann Hum Genet 2008; 72:163-9. [PMID: 18269685 DOI: 10.1111/j.1469-1809.2007.00416.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Type 2 diabetes (T2D) has been linked to chromosome 1q21-24 in multiple samples, including a Utah family sample. Variants in 13 of the numerous candidate genes in the 1q region were tested for association with T2D in a Utah case-control sample. The most promising, 19 variants in 6 candidates, were genotyped on the Utah family sample. Herein, we tested the 19 variants individually and in pairs for an effect on T2D risk in family members using a logistic regression model that accounted for gender, age, and BMI and attributed residual genetic effects to a polygenic component. Seven variants increased risk significantly through 5 pairs of interactions. The significant variant pairs were apolipoprotein A-II (APOA2) rs6413453 interacting with calsequestrin 1 (CASQ1) rs617698, dual specificity phosphatase 12 (DUSP12) rs1503814, and retinoid X receptor gamma (RXRG) rs10918169, a poly-T insertion-deletion polymorphism in liver pyruvate kinase (PKLR) interacting with APOA2 rs12143180, and DUSP12 rs1027702 interacting with RXRG rs10918169. Genotypes of these 5 variant pairs accounted for 25.8% of the genetic variance in T2D in these pedigrees.
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Affiliation(s)
- S J Hasstedt
- Department of Human Genetics, University of Utah, 15 N. 2030 E., Salt Lake City, UT 84112, USA.
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Mitchell-Olds T, Willis JH, Goldstein DB. Which evolutionary processes influence natural genetic variation for phenotypic traits? Nat Rev Genet 2007; 8:845-56. [DOI: 10.1038/nrg2207] [Citation(s) in RCA: 384] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Prashar A, Guggenheim JA, Erichsen JT, Hocking PM, Morgan JE. Measurement of intraocular pressure (IOP) in chickens using a rebound tonometer: quantitative evaluation of variance due to position inaccuracies. Exp Eye Res 2007; 85:563-71. [PMID: 17719031 DOI: 10.1016/j.exer.2007.07.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 06/12/2007] [Accepted: 07/06/2007] [Indexed: 11/13/2022]
Abstract
Intraocular pressure (IOP), an important risk factor for glaucoma, is a continuous trait determined by a complex set of genetic and environmental factors that are largely unknown. Genetic studies in laboratory animals may facilitate the identification of genes that affect IOP. We examined the use of the rebound tonometer for measuring IOP in non-anaesthetised birds, along with the device's robustness to alignment errors. Calibration curves were obtained by measuring the IOP of cannulated chicken eyes with the rebound tonometer over a range of pressures. To simulate different types of alignment errors that might be expected with measurement of IOP in alert chickens, for some calibrations the tonometer was positioned (1) at various distances from the cornea, (2) laterally displaced from the visual axis, or (3) angled away from the visual axis. In vivo measurements were taken on three-week-old alert chickens from a layer line, a broiler line, and a layer-broiler "advanced intercross line" (AIL) designed to facilitate QTL mapping. The rebound tonometer showed excellent linearity (R2=0.95-0.99) during calibration, as well as robustness to variation in the probe-to-cornea distance over the range 3-5mm and to lateral displacement over the range 0-2mm. However, the tonometer appeared less robust to off-axis misalignment over the range 0-20 degrees (P<0.05). Also, the slope of calibration curves sometimes differed between eyes (P<0.001), presumably reflecting differences in ocular structure. The IOP measured in non-anaesthetised three-week-old AIL chickens was 17.51+/-0.13 mmHg (mean+/-S.E.; N=105 birds). IOP was significantly associated with corneal thickness (P<0.05) and body weight (P<0.001) in a regression model. Replicate measurements were necessary in order to gauge IOP accurately in individual birds; a series of seven tonometry sessions over a 12-h period during the light phase of the light/dark cycle permitted IOP to be measured with a 95% CI of +/-0.7 mmHg. IOP did not differ significantly between the broiler and layer chicken lines which served as the progenitor lines for the AIL. In conclusion, the rebound tonometer permits rapid estimation of IOP in chickens and is well tolerated. The small alignment errors that are expected when taking measurements in non-anaesthetised animals are unlikely to affect accuracy. Since high IOP is a major risk factor for glaucoma, identifying QTL controlling IOP may offer future health benefits. However, our preliminary findings highlight several obstacles to mapping such QTL using the chicken advanced intercross line evaluated here.
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Affiliation(s)
- A Prashar
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
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Luft FC. A high mobility group box-containing transcription factor leads to diabetes risk. J Mol Med (Berl) 2006; 84:985-7. [PMID: 17091236 DOI: 10.1007/s00109-006-0124-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Accepted: 10/06/2006] [Indexed: 10/23/2022]
Affiliation(s)
- Friedrich C Luft
- Franz Volhard Clinic, HELIOS Kliniken Berlin, Medical Faculty of the Charité, Humboldt University, Berlin-Buch, Germany.
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