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Luo G, Xiang L, Xiao L. Acetyl-CoA Deficiency Is Involved in the Regulation of Iron Overload on Lipid Metabolism in Apolipoprotein E Knockout Mice. Molecules 2022; 27:molecules27154966. [PMID: 35956917 PMCID: PMC9370536 DOI: 10.3390/molecules27154966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 11/16/2022] Open
Abstract
The role of dietary iron supplementation in the development of nonalcoholic fatty liver disease (NAFLD) remains controversial. This study aimed to investigate the effect of excess dietary iron on NAFLD development and the underlying mechanism. Apolipoprotein E knockout mice were fed a chow diet, a high-fat diet (HFD), or an HFD containing 2% carbonyl iron (HFD + Fe) for 16 weeks. The serum and liver samples were acquired for biochemical and histopathological examinations. Isobaric tags for relative and absolute quantitation were performed to identify differentially expressed proteins in different groups. Excess dietary iron alleviated HFD-induced NAFLD, as evidenced by significant decreases in serum/the hepatic accumulation of lipids and the NAFLD scores in HFD + Fe-fed mice compared with those in HFD-fed mice. The hepatic acetyl-CoA level was markedly decreased in the HFD + Fe group compared with that in the HFD group. Important enzymes involved in the source and destination of acetyl-CoA were differentially expressed between the HFD and HFD + Fe groups, including the enzymes associated with cholesterol metabolism, glycolysis, and the tricarboxylic acid cycle. Furthermore, iron overload-induced mitochondrial dysfunction and oxidative stress occurred in mouse liver, as evidenced by decreases in the mitochondrial membrane potential and antioxidant expression. Therefore, iron overload regulates lipid metabolism by leading to an acetyl-CoA shortage that reduces cholesterol biosynthesis and might play a role in NAFLD pathogenesis. Iron overload-induced oxidative stress and mitochondrial dysfunction may impair acetyl-CoA formation from pyruvate and β-oxidation. Our study provides acetyl-CoA as a novel perspective for investigating the pathogenesis of NAFLD.
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Affiliation(s)
- Gang Luo
- Department of Health Toxicology, Xiangya School of Public Health, Central South University, Changsha 410078, China
| | - Lu Xiang
- Department of Nutrition Science and Food Hygiene, Xiangya School of Public Health, Central South University, Changsha 410078, China
| | - Lin Xiao
- Department of Nutrition Science and Food Hygiene, Xiangya School of Public Health, Central South University, Changsha 410078, China
- Correspondence: ; Tel.: +86-731-8448-7130
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2
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High Iron Exposure from the Fetal Stage to Adulthood in Mice Alters Lipid Metabolism. Nutrients 2022; 14:nu14122451. [PMID: 35745181 PMCID: PMC9227341 DOI: 10.3390/nu14122451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 12/11/2022] Open
Abstract
Iron supplementation is recommended during pregnancy and fetal growth. However, excess iron exposure may increase the risk of abnormal fetal development. We investigated the potential side effects of high iron levels in fetuses and through their adult life. C57BL/6J pregnant mice from 2 weeks of gestation and their offspring until 30 weeks were fed a control (CTRL, FeSO4 0 g/1 kg) or high iron (HFe, FeSO4 9.9 g/1 kg) diets. HFe group showed higher iron accumulation in the liver with increased hepcidin, reduced TfR1/2 mRNAs, and lowered ferritin heavy chain (FTH) proteins in both liver and adipose tissues despite iron loading. HFe decreased body weight, fat weight, adipocyte size, and triglyceride levels in the blood and fat, along with downregulation of lipogenesis genes, including PPARγ, C/EBPα, SREBP1c, FASN, and SCD1, and fatty acid uptake and oxidation genes, such as CD36 and PPARα. UCP2, adiponectin, and mRNA levels of antioxidant genes such as GPX4, HO-1, and NQO1 were increased in the HFe group, while total glutathione was reduced. We conclude that prolonged exposure to high iron from the fetal stage to adulthood may decrease fat accumulation by altering ferritin expression, adipocyte differentiation, and triglyceride metabolism, resulting in an alteration in normal growth.
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Anderson GJ, Bardou-Jacquet E. Revisiting hemochromatosis: genetic vs. phenotypic manifestations. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:731. [PMID: 33987429 PMCID: PMC8106074 DOI: 10.21037/atm-20-5512] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Iron overload disorders represent an important class of human diseases. Of the primary iron overload conditions, by far the most common and best studied is HFE-related hemochromatosis, which results from homozygosity for a mutation leading to the C282Y substitution in the HFE protein. This disease is characterized by reduced expression of the iron-regulatory hormone hepcidin, leading to increased dietary iron absorption and iron deposition in multiple tissues including the liver, pancreas, joints, heart and pituitary. The phenotype of HFE-related hemochromatosis is quite variable, with some individuals showing little or no evidence of increased body iron, yet others showing severe iron loading, tissue damage and clinical sequelae. The majority of genetically predisposed individuals show at least some evidence of iron loading (increased transferrin saturation and serum ferritin), but a minority show clinical symptoms and severe consequences are rare. Thus, the disorder has a high biochemical penetrance, but a low clinical prevalence. Nevertheless, it is such a common condition in Caucasian populations (1:100–200) that it remains an important clinical entity. The phenotypic variability can largely be explained by a range of environmental, genetic and physiological factors. Men are far more likely to manifest significant disease than women, with the latter losing iron through menstrual blood loss and childbirth. Other forms of blood loss, immune system influences, the amount of bioavailable iron in the diet and lifestyle factors such as high alcohol intake can also contribute to iron loading and disease expression. Polymorphisms in a range of genes have been linked to variations in body iron levels, both in the general population and in hemochromatosis. Some of the genes identified play well known roles in iron homeostasis, yet others are novel. Other factors, including both co-morbidities and genetic polymorphisms, do not affect iron levels per se, but determine the propensity for tissue pathology.
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Affiliation(s)
- Gregory J Anderson
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute and School of Chemistry and Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Edouard Bardou-Jacquet
- Liver Disease Department, University of Rennes and French Reference Center for Hemochromatosis and Iron Metabolism Disease, Rennes, France
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4
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In silico mapping of quantitative trait loci (QTL) regulating the milk ionome in mice identifies a milk iron locus on chromosome 1. Mamm Genome 2018; 29:632-655. [DOI: 10.1007/s00335-018-9762-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Indexed: 01/06/2023]
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5
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McLachlan S, Page KE, Lee SM, Loguinov A, Valore E, Hui ST, Jung G, Zhou J, Lusis AJ, Fuqua B, Ganz T, Nemeth E, Vulpe CD. Hamp1 mRNA and plasma hepcidin levels are influenced by sex and strain but do not predict tissue iron levels in inbred mice. Am J Physiol Gastrointest Liver Physiol 2017; 313:G511-G523. [PMID: 28798083 PMCID: PMC5792216 DOI: 10.1152/ajpgi.00307.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 07/17/2017] [Accepted: 07/24/2017] [Indexed: 01/31/2023]
Abstract
Iron homeostasis is tightly regulated, and the peptide hormone hepcidin is considered to be a principal regulator of iron metabolism. Previous studies in a limited number of mouse strains found equivocal sex- and strain-dependent differences in mRNA and serum levels of hepcidin and reported conflicting data on the relationship between hepcidin (Hamp1) mRNA levels and iron status. Our aim was to clarify the relationships between strain, sex, and hepcidin expression by examining multiple tissues and the effects of different dietary conditions in multiple inbred strains. Two studies were done: first, Hamp1 mRNA, liver iron, and plasma diferric transferrin levels were measured in 14 inbred strains on a control diet; and second, Hamp1 mRNA and plasma hepcidin levels in both sexes and iron levels in the heart, kidneys, liver, pancreas, and spleen in males were measured in nine inbred/recombinant inbred strains raised on an iron-sufficient or high-iron diet. Both sex and strain have a significant effect on both hepcidin mRNA (primarily a sex effect) and plasma hepcidin levels (primarily a strain effect). However, liver iron and diferric transferrin levels are not predictors of Hamp1 mRNA levels in mice fed iron-sufficient or high-iron diets, nor are the Hamp1 mRNA and plasma hepcidin levels good predictors of tissue iron levels, at least in males. We also measured plasma erythroferrone, performed RNA-sequencing analysis of liver samples from six inbred strains fed the iron-sufficient, low-iron, or high-iron diets, and explored differences in gene expression between the strains with the highest and lowest hepcidin levels.NEW & NOTEWORTHY Both sex and strain have a significant effect on both hepcidin mRNA (primarily a sex effect) and plasma hepcidin levels (primarily a strain effect). Liver iron and diferric transferrin levels are not predictors of Hamp1 mRNA levels in mice, nor are the Hamp1 mRNA and plasma hepcidin levels good predictors of tissue iron levels, at least in males.
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Affiliation(s)
- Stela McLachlan
- Centre for Population Health Sciences, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, United Kingdom;
| | - Kathryn E. Page
- 2Department of Nutritional Science & Toxicology, University of California, Berkeley, California;
| | - Seung-Min Lee
- 3Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, Korea;
| | - Alex Loguinov
- 5Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Erika Valore
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Simon T. Hui
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Grace Jung
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Jie Zhou
- 5Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Aldons J. Lusis
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Brie Fuqua
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Tomas Ganz
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Elizabeta Nemeth
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Chris D. Vulpe
- 2Department of Nutritional Science & Toxicology, University of California, Berkeley, California; ,5Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
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Heidari M, Johnstone DM, Bassett B, Graham RM, Chua ACG, House MJ, Collingwood JF, Bettencourt C, Houlden H, Ryten M, Olynyk JK, Trinder D, Milward EA. Brain iron accumulation affects myelin-related molecular systems implicated in a rare neurogenetic disease family with neuropsychiatric features. Mol Psychiatry 2016; 21:1599-1607. [PMID: 26728570 PMCID: PMC5078858 DOI: 10.1038/mp.2015.192] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 10/01/2015] [Accepted: 10/26/2015] [Indexed: 11/25/2022]
Abstract
The 'neurodegeneration with brain iron accumulation' (NBIA) disease family entails movement or cognitive impairment, often with psychiatric features. To understand how iron loading affects the brain, we studied mice with disruption of two iron regulatory genes, hemochromatosis (Hfe) and transferrin receptor 2 (Tfr2). Inductively coupled plasma atomic emission spectroscopy demonstrated increased iron in the Hfe-/- × Tfr2mut brain (P=0.002, n ≥5/group), primarily localized by Perls' staining to myelinated structures. Western immunoblotting showed increases of the iron storage protein ferritin light polypeptide and microarray and real-time reverse transcription-PCR revealed decreased transcript levels (P<0.04, n ≥5/group) for five other NBIA genes, phospholipase A2 group VI, fatty acid 2-hydroxylase, ceruloplasmin, chromosome 19 open reading frame 12 and ATPase type 13A2. Apart from the ferroxidase ceruloplasmin, all are involved in myelin homeostasis; 16 other myelin-related genes also showed reduced expression (P<0.05), although gross myelin structure and integrity appear unaffected (P>0.05). Overlap (P<0.0001) of differentially expressed genes in Hfe-/- × Tfr2mut brain with human gene co-expression networks suggests iron loading influences expression of NBIA-related and myelin-related genes co-expressed in normal human basal ganglia. There was overlap (P<0.0001) of genes differentially expressed in Hfe-/- × Tfr2mut brain and post-mortem NBIA basal ganglia. Hfe-/- × Tfr2mut mice were hyperactive (P<0.0112) without apparent cognitive impairment by IntelliCage testing (P>0.05). These results implicate myelin-related systems involved in NBIA neuropathogenesis in early responses to iron loading. This may contribute to behavioral symptoms in NBIA and hemochromatosis and is relevant to patients with abnormal iron status and psychiatric disorders involving myelin abnormalities or resistant to conventional treatments.
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Affiliation(s)
- M Heidari
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
| | - D M Johnstone
- Bosch Institute and Discipline of Physiology, University of Sydney, Sydney, NSW, Australia
| | - B Bassett
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
| | - R M Graham
- School of Biomedical Sciences and Curtin Health Innovation Research Institute - Biosciences, Curtin University of Technology, Bentley, WA, Australia
| | - A C G Chua
- School of Medicine and Pharmacology, University of Western Australia, Fiona Stanley Hospital, Murdoch, WA, Australia,Harry Perkins Institute of Medical Research, Murdoch, WA, Australia
| | - M J House
- School of Physics, University of Western Australia, Crawley, WA, Australia
| | - J F Collingwood
- Warwick Engineering in Biomedicine, School of Engineering, University of Warwick, Coventry, UK
| | - C Bettencourt
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK,Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - H Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - M Ryten
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK,Department of Medical and Molecular Genetics, King's College London, London, UK
| | - J K Olynyk
- School of Biomedical Sciences and Curtin Health Innovation Research Institute - Biosciences, Curtin University of Technology, Bentley, WA, Australia,Institute for Immunology and Infectious Diseases, Murdoch University, Perth, WA, Australia,Department of Gastroenterology and Hepatology, Fiona Stanley Hospital, The University of Western Australia, Murdoch, WA, Australia,Department of Gastroenterology and Hepatology, Fremantle Hospital, Fremantle, WA, Australia
| | - D Trinder
- School of Medicine and Pharmacology, University of Western Australia, Fiona Stanley Hospital, Murdoch, WA, Australia,Harry Perkins Institute of Medical Research, Murdoch, WA, Australia
| | - E A Milward
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia,School of Biomedical Sciences and Pharmacy MSB, University of Newcastle, Callaghan, NSW 2308, Australia. E-mail:
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7
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Heritability of in vitro phenotypes exhibited by murine adipose-derived stromal cells. Mamm Genome 2016; 27:460-8. [PMID: 27393554 DOI: 10.1007/s00335-016-9655-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/27/2016] [Indexed: 01/17/2023]
Abstract
Adipose-derived stromal cells (ADSCs) exhibit significant potential as therapeutic agents to promote tissue regeneration. Success of ADSC-based therapies is dependent upon efficient cell expansion in vitro as well as postinjection survival in the caustic milieu of damaged tissue. Genetic background regulates ADSC proliferative capacity and stress resistance, but the extent of the genetic effect size is not completely defined. The present study aimed to quantify phenotypic ranges and heritability of in vitro ADSC characteristics. ADSCs were isolated from mice representing 16 genetically diverse inbred mouse strains, including 12 classical inbred strains and four wild-derived strains. Cells were grown in vitro, and proliferative capacity and oxidative stress resistance were assessed. The fold change for ADSC growth ranged from 0.87 (BALB/cByJ) to 23.60 (POHN/DehJ), relative to original seeding density. The heritability of proliferative capacity was estimated to be 0.6462 (p = 9.967 × 10(-15)), and this phenotype was not associated with other ADSC traits. Cell viability following H2O2 treatment ranged from 39.81 % (CAST/EiJ) to 91.60 % (DBA/2 J), and the heritability of this phenotype was calculated as 0.6146 (p = 1.22 × 10(-12)). Relationships between cell viability and weight of the donor fat pad were also discovered. Donor genetic background is a major determinant of in vitro ADSC phenotypes. This study supports the development of forward genetics strategies to identify genes that underlie ADSC phenotypic diversity, which will inform efforts to improve cell-based therapies.
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8
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Bettencourt C, Forabosco P, Wiethoff S, Heidari M, Johnstone DM, Botía JA, Collingwood JF, Hardy J, Milward EA, Ryten M, Houlden H. Gene co-expression networks shed light into diseases of brain iron accumulation. Neurobiol Dis 2016; 87:59-68. [PMID: 26707700 PMCID: PMC4731015 DOI: 10.1016/j.nbd.2015.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 11/18/2015] [Accepted: 12/14/2015] [Indexed: 12/21/2022] Open
Abstract
Aberrant brain iron deposition is observed in both common and rare neurodegenerative disorders, including those categorized as Neurodegeneration with Brain Iron Accumulation (NBIA), which are characterized by focal iron accumulation in the basal ganglia. Two NBIA genes are directly involved in iron metabolism, but whether other NBIA-related genes also regulate iron homeostasis in the human brain, and whether aberrant iron deposition contributes to neurodegenerative processes remains largely unknown. This study aims to expand our understanding of these iron overload diseases and identify relationships between known NBIA genes and their main interacting partners by using a systems biology approach. We used whole-transcriptome gene expression data from human brain samples originating from 101 neuropathologically normal individuals (10 brain regions) to generate weighted gene co-expression networks and cluster the 10 known NBIA genes in an unsupervised manner. We investigated NBIA-enriched networks for relevant cell types and pathways, and whether they are disrupted by iron loading in NBIA diseased tissue and in an in vivo mouse model. We identified two basal ganglia gene co-expression modules significantly enriched for NBIA genes, which resemble neuronal and oligodendrocytic signatures. These NBIA gene networks are enriched for iron-related genes, and implicate synapse and lipid metabolism related pathways. Our data also indicates that these networks are disrupted by excessive brain iron loading. We identified multiple cell types in the origin of NBIA disorders. We also found unforeseen links between NBIA networks and iron-related processes, and demonstrate convergent pathways connecting NBIAs and phenotypically overlapping diseases. Our results are of further relevance for these diseases by providing candidates for new causative genes and possible points for therapeutic intervention.
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Affiliation(s)
- Conceição Bettencourt
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.
| | - Paola Forabosco
- Istituto di Ricerca Genetica e Biomedica CNR, Cagliari, Italy
| | - Sarah Wiethoff
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK; Center for Neurology and Hertie Institute for Clinical Brain Research, Eberhard-Karls-University, Tübingen, Germany
| | - Moones Heidari
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia; Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, NSW, Australia
| | - Daniel M Johnstone
- Bosch Institute and Discipline of Physiology, University of Sydney, NSW, Australia
| | - Juan A Botía
- Department of Medical and Molecular Genetics, King's College London, London, UK
| | | | - John Hardy
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Elizabeth A Milward
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia; Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, NSW, Australia
| | - Mina Ryten
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK; Department of Medical and Molecular Genetics, King's College London, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
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Church RJ, Wu H, Mosedale M, Sumner SJ, Pathmasiri W, Kurtz CL, Pletcher MT, Eaddy JS, Pandher K, Singer M, Batheja A, Watkins PB, Adkins K, Harrill AH. A systems biology approach utilizing a mouse diversity panel identifies genetic differences influencing isoniazid-induced microvesicular steatosis. Toxicol Sci 2014; 140:481-92. [PMID: 24848797 DOI: 10.1093/toxsci/kfu094] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Isoniazid (INH), the mainstay therapeutic for tuberculosis infection, has been associated with rare but serious hepatotoxicity in the clinic. However, the mechanisms underlying inter-individual variability in the response to this drug have remained elusive. A genetically diverse mouse population model in combination with a systems biology approach was utilized to identify transcriptional changes, INH-responsive metabolites, and gene variants that contribute to the liver response in genetically sensitive individuals. Sensitive mouse strains developed severe microvesicular steatosis compared with corresponding vehicle control mice following 3 days of oral treatment with INH. Genes involved in mitochondrial dysfunction were enriched among liver transcripts altered with INH treatment. Those associated with INH treatment and susceptibility to INH-induced steatosis in the liver included apolipoprotein A-IV, lysosomal-associated membrane protein 1, and choline phosphotransferase 1. These alterations were accompanied by metabolomic changes including reduced levels of glutathione and the choline metabolites betaine and phosphocholine, suggesting that oxidative stress and reduced lipid export may additionally contribute to INH-induced steatosis. Finally, genome-wide association mapping revealed that polymorphisms in perilipin 2 were linked to increased triglyceride levels following INH treatment, implicating a role for inter-individual differences in lipid packaging in the susceptibility to INH-induced steatosis. Taken together, our data suggest that INH-induced steatosis is caused by not one, but multiple events involving lipid retention in the livers of genetically sensitive individuals. This work also highlights the value of using a mouse diversity panel to investigate drug-induced responses across a diverse population.
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Affiliation(s)
- Rachel J Church
- Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709
| | - Hong Wu
- Drug Safety Research and Development, Pfizer Global Research and Development, Groton, Connecticut 06340
| | - Merrie Mosedale
- Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709
| | - Susan J Sumner
- Discovery Sciences, RTI International, Research Triangle Park, North Carolina 27709
| | - Wimal Pathmasiri
- Discovery Sciences, RTI International, Research Triangle Park, North Carolina 27709
| | - Catherine L Kurtz
- Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709
| | - Mathew T Pletcher
- Drug Safety Research and Development, Pfizer Global Research and Development, Groton, Connecticut 06340
| | - John S Eaddy
- Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709
| | - Karamjeet Pandher
- Drug Safety Research and Development, Pfizer Global Research and Development, Groton, Connecticut 06340
| | - Monica Singer
- Janssen Research and Development, Drug Safety Sciences, Raritan, New Jersey 08869
| | - Ameesha Batheja
- Janssen Research and Development, Drug Safety Sciences, Raritan, New Jersey 08869
| | - Paul B Watkins
- Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709 Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Karissa Adkins
- Drug Safety Research and Development, Pfizer Global Research and Development, Groton, Connecticut 06340
| | - Alison H Harrill
- Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709 Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 The University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
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10
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Delaby C, Oustric V, Schmitt C, Muzeau F, Robreau AM, Letteron P, Couchi E, Yu A, Lyoumi S, Deybach JC, Puy H, Karim Z, Beaumont C, Grandchamp B, Demant P, Gouya L. Epistasis in iron metabolism: complex interactions between Cp, Mon1a, and Slc40a1 loci and tissue iron in mice. Mamm Genome 2013; 24:427-38. [PMID: 24121729 DOI: 10.1007/s00335-013-9479-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 08/29/2013] [Indexed: 11/29/2022]
Abstract
Disorders of iron metabolism are among the most common acquired and constitutive diseases. Hemochromatosis has a solid genetic basis and in Northern European populations it is usually associated with homozygosity for the C282Y mutation in the HFE protein. However, the penetrance of this mutation is incomplete and the clinical presentation is highly variable. The rare and common variants identified so far as genetic modifiers of HFE-related hemochromatosis are unable to account for the phenotypic heterogeneity of this disorder. There are wide variations in the basal iron status of common inbred mouse strains, and this diversity may reflect the genetic background of the phenotypic diversity under pathological conditions. We therefore examined the genetic basis of iron homeostasis using quantitative trait loci mapping applied to the HcB-15 recombinant congenic strains for tissue and serum iron indices. Two highly significant QTL containing either the N374S Mon1a mutation or the Ferroportin locus were found to be major determinants in spleen and liver iron loading. Interestingly, when considering possible epistatic interactions, the effects of Mon1a on macrophage iron export are conditioned by the genotype at the Slc40a1 locus. Only mice that are C57BL/10ScSnA homozygous at both loci display a lower spleen iron burden. Furthermore, the liver-iron lowering effect of the N374S Mon1a mutation is observed only in mice that display a nonsense mutation in the Ceruloplasmin (Cp) gene. This study highlights the existence of genetic interactions between Cp, Mon1a, and the Slc40a1 locus in iron metabolism, suggesting that epistasis may be a crucial determinant of the variable biological and clinical presentations in iron disorders.
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11
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Guo X, Zhang Z, Zhang F, Tao Y, An P, Wu Q, Wang CY, Knutson MD, Wang F. Fine-mapping and genetic analysis of the loci affecting hepatic iron overload in mice. PLoS One 2013; 8:e63280. [PMID: 23675470 PMCID: PMC3651197 DOI: 10.1371/journal.pone.0063280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 03/29/2013] [Indexed: 12/12/2022] Open
Abstract
The liver, as the major organ for iron storage and production of hepcidin, plays pivotal roles in maintaining mammalian iron homeostasis. A previous study showed that Quantitative Trait Loci (QTLs) on chromosome 7 (Chr7) and 16 (Chr16) may control hepatic non-heme iron overload in an F2 intercross derived from C57BL/6J (B6) and SWR/J (SWR) mice. In this study, we aimed to validate the existence of these loci and identify the genes responsible for the phenotypic variations by generating congenic mice carrying SWR chromosome segments expanding these QTLs (D7Mit68-D7Mit71 and D16Mit125-D16Mit185, respectively). We excluded involvement of Chr7 based on the lack of iron accumulation in congenic mice. In contrast, liver iron accumulation was observed in Chr16 congenic mice. Through use of a series of subcongenic murine lines the interval on Chr16 was further fine-mapped to a 0.8 Mb segment spanning 11 genes. We found that the mRNA expression pattern in the liver remained unchanged for all 11 genes tested. Most importantly, we detected 4 missense mutations in 3 candidate genes including Sidt1 (P172R), Spice1(R708S), Boc (Q1051R) and Boc (S450-insertion in B6 allele) in the liver of SWR homozygous congenic mice. To further delineate potential modifier gene(s), we reconstituted seven candidate genes, Sidt1, Boc, Zdhhc23, Gramd1c, Atp6v1a, Naa50 and Gtpbp8, in mouse liver through hydrodynamic transfection. However, we were unable to detect significant changes in liver iron levels upon reconstitution of these candidate genes. Taken together, our work provides strong genetic evidence of the existence of iron modifiers on Chr16. Moreover, we were able to delineate the phenotypically responsible region to a 0.8 Mb region containing 11 coding genes, 3 of which harbor missense mutations, using a series of congenic mice.
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Affiliation(s)
- Xin Guo
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Zhuzhen Zhang
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Fan Zhang
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Yunlong Tao
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Peng An
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Qian Wu
- Key Laboratory of Nutrition and Metabolism, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, China
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
| | - Chia-Yu Wang
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, Florida, United States of America
| | - Mitchell D. Knutson
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, Florida, United States of America
| | - Fudi Wang
- Department of Nutrition, Institute of
Nutrition and Food Safety, School of Public Health, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou,
P.R. China
- * E-mail:
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Acikyol B, Graham RM, Trinder D, House MJ, Olynyk JK, Scott RJ, Milward EA, Johnstone DM. Brain transcriptome perturbations in the transferrin receptor 2 mutant mouse support the case for brain changes in iron loading disorders, including effects relating to long-term depression and long-term potentiation. Neuroscience 2013; 235:119-28. [PMID: 23333676 DOI: 10.1016/j.neuroscience.2013.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 12/14/2012] [Accepted: 01/02/2013] [Indexed: 11/16/2022]
Abstract
Iron abnormalities within the brain are associated with several rare but severe neurodegenerative conditions. There is growing evidence that more common systemic iron loading disorders such as hemochromatosis can also have important effects on the brain. To identify features that are common across different forms of hemochromatosis, we used microarray and real-time reverse transcription polymerase chain reaction (RT-PCR) to assess brain transcriptome profiles of transferrin receptor 2 mutant mice (Tfr2(mut)), a model of a rare type of hereditary hemochromatosis, relative to wildtype control mice. The results were compared with our previous findings in dietary iron-supplemented wildtype mice and Hfe(-/-) mice, a model of a common type of hereditary hemochromatosis. For transcripts showing significant changes relative to controls across all three models, there was perfect (100%) directional concordance (i.e. transcripts were increased in all models or decreased in all models). Comparison of the two models of hereditary hemochromatosis, which showed more pronounced changes than the dietary iron-supplemented mice, revealed numerous common molecular effects. Pathway analyses highlighted changes for genes relating to long-term depression (6.8-fold enrichment, p=5.4×10(-7)) and, to a lesser extent, long-term potentiation (3.7-fold enrichment, p=0.01), with generalized reductions in transcription of key genes from these pathways, which are involved in modulating synaptic strength and efficacy and are essential for memory and learning. The agreement across the models suggests the findings are robust and strengthens previous evidence that iron loading disorders affect the brain. Perturbations of brain phenomena such as long-term depression and long-term potentiation might partly explain neurologic symptoms reported for some hemochromatosis patients.
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Affiliation(s)
- B Acikyol
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
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13
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Delima RD, Chua ACG, Tirnitz-Parker JEE, Gan EK, Croft KD, Graham RM, Olynyk JK, Trinder D. Disruption of hemochromatosis protein and transferrin receptor 2 causes iron-induced liver injury in mice. Hepatology 2012; 56:585-93. [PMID: 22383097 DOI: 10.1002/hep.25689] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 02/19/2012] [Indexed: 12/21/2022]
Abstract
UNLABELLED Mutations in hemochromatosis protein (HFE) or transferrin receptor 2 (TFR2) cause hereditary hemochromatosis (HH) by impeding production of the liver iron-regulatory hormone, hepcidin (HAMP). This study examined the effects of disruption of Hfe or Tfr2, either alone or together, on liver iron loading and injury in mouse models of HH. Iron status was determined in Hfe knockout (Hfe(-/-)), Tfr2 Y245X mutant (Tfr2(mut)), and double-mutant (Hfe(-/-) ×Tfr2(mut) ) mice by measuring plasma and liver iron levels. Plasma alanine transaminase (ALT) activity, liver histology, and collagen deposition were evaluated to assess liver injury. Hepatic oxidative stress was assessed by measuring superoxide dismutase (SOD) activity and F(2)-isoprostane levels. Gene expression was measured by real-time polymerase chain reaction. Hfe(-/-) ×Tfr2(mut) mice had elevated hepatic iron with a periportal distribution and increased plasma iron, transferrin saturation, and non-transferrin-bound iron, compared with Hfe(-/-), Tfr2(mut), and wild-type (WT) mice. Hamp1 expression was reduced to 40% (Hfe(-/-) and Tfr2(mut) ) and 1% (Hfe(-/-) ×Tfr2(mut)) of WT values. Hfe(-/-) ×Tfr2(mut) mice had elevated plasma ALT activity and mild hepatic inflammation with scattered aggregates of infiltrating inflammatory cluster of differentiation 45 (CD45)-positive cells. Increased hepatic hydoxyproline levels as well as Sirius red and Masson's Trichrome staining demonstrated advanced portal collagen deposition. Hfe(-/-) and Tfr2(mut) mice had less hepatic inflammation and collagen deposition. Liver F(2) -isoprostane levels were elevated, and copper/zinc and manganese SOD activities decreased in Hfe(-/-) ×Tfr2(mut), Tfr2(mut), and Hfe(-/-) mice, compared with WT mice. CONCLUSION Disruption of both Hfe and Tfr2 caused more severe hepatic iron overload with more advanced lipid peroxidation, inflammation, and portal fibrosis than was observed with the disruption of either gene alone. The Hfe(-/-) ×Tfr2(mut) mouse model of iron-induced liver injury reflects the liver injury phenotype observed in human HH.
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Affiliation(s)
- Roheeth D Delima
- School of Medicine and Pharmacology, Fremantle Hospital, University of Western Australia, Fremantle, Western Australia, Australia
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14
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Hadsell DL, Wei J, Olea W, Hadsell LA, Renwick A, Thomson PC, Shariflou M, Williamson P. In silico QTL mapping of maternal nurturing ability with the mouse diversity panel. Physiol Genomics 2012; 44:787-98. [PMID: 22759921 DOI: 10.1152/physiolgenomics.00159.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Significant variation exists for maternal nurturing ability in inbred mice. Although classical mapping approaches have identified quantitative trait loci (QTL) that may account for this variation, the underlying genes are unknown. In this study, lactation performance data among the mouse diversity panel were used to map genomic regions associated with this variation. Females from each of 32 inbred strains (n = 8-19 dams/strain) were studied during the first 8 days of lactation by allowing them to raise weight- and size-normalized cross-foster litters (10 pups/litter). Average daily weight gain (ADG) of litters served as the primary indicator of milk production. The number of pups successfully reared to 8 days (PNUM8) also served as a related indicator of maternal performance. Initial haplotype association analysis using a Bonferroni-corrected, genome-wide threshold revealed 10 and 15 associations encompassing 11 and 13 genes for ADG and PNUM8, respectively. The most significant of these associated haplotype blocks were found on MMU 8, 11, and 19 and contained the genes Nr3c2, Egfr, Sec61g, and Gnaq. Lastly, two haplotype blocks on MMU9 were detected in association with PNUM8. These overlapped with the previously described maternal performance QTL, Neogq1. These results suggest that the application of in silico QTL mapping is a useful tool in discovering the presence of novel candidate genes involved in determining lactation capacity in mice.
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Affiliation(s)
- D L Hadsell
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030-2600, USA.
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15
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Yin L, Unger EL, Jellen LC, Earley CJ, Allen RP, Tomaszewicz A, Fleet JC, Jones BC. Systems genetic analysis of multivariate response to iron deficiency in mice. Am J Physiol Regul Integr Comp Physiol 2012; 302:R1282-96. [PMID: 22461179 DOI: 10.1152/ajpregu.00634.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to identify genes that influence iron regulation under varying dietary iron availability. Male and female mice from 20+ BXD recombinant inbred strains were fed iron-poor or iron-adequate diets from weaning until 4 mo of age. At death, the spleen, liver, and blood were harvested for the measurement of hemoglobin, hematocrit, total iron binding capacity, transferrin saturation, and liver, spleen and plasma iron concentration. For each measure and diet, we found large, strain-related variability. A principal-components analysis (PCA) was performed on the strain means for the seven parameters under each dietary condition for each sex, followed by quantitative trait loci (QTL) analysis on the factors. Compared with the iron-adequate diet, iron deficiency altered the factor structure of the principal components. QTL analysis, combined with PosMed (a candidate gene searching system) published gene expression data and literature citations, identified seven candidate genes, Ptprd, Mdm1, Picalm, lip1, Tcerg1, Skp2, and Frzb based on PCA factor, diet, and sex. Expression of each of these is cis-regulated, significantly correlated with the corresponding PCA factor, and previously reported to regulate iron, directly or indirectly. We propose that polymorphisms in multiple genes underlie individual differences in iron regulation, especially in response to dietary iron challenge. This research shows that iron management is a highly complex trait, influenced by multiple genes. Systems genetics analysis of iron homeostasis holds promise for developing new methods for prevention and treatment of iron deficiency anemia and related diseases.
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Affiliation(s)
- Lina Yin
- Graduate Program in Neuroscience,The Pennsylvania State University, PA 16802, USA
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