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Morais MA, Franco BS, Holanda ASS, de Paula Simino LA, Veras ACC, Torsoni MA, Manconi M, Torsoni AS, Esteves AM. Protein tyrosine phosphatase receptor type delta (PTPRD) gene in an animal model of restless legs syndrome. J Sleep Res 2023; 32:e13716. [PMID: 36053904 DOI: 10.1111/jsr.13716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/21/2022] [Accepted: 07/27/2022] [Indexed: 11/28/2022]
Abstract
The pathophysiology of the restless legs syndrome (RLS) is related to dopaminergic dysfunction, reduced iron and variations in gene expression, such as the protein tyrosine phosphatase receptor type delta gene (PTPRD). Animal models could be key to achieving a mechanistic understanding of RLS and to facilitate efficient platforms for evaluating new therapeutics. Thus, the aim of this study was to evaluate the expression of PTPRD, of genes and proteins associated with RLS, the sleep patterns and the cardiovascular parameters in an animal model of RLS (spontaneously hypertensive rat [SHR]). Rats were divided into two groups: (i) Wistar-Kyoto and (ii) SHR. Cardiovascular parameters were assessed by tail plethysmography. Polysomnography was used to analyse the sleep pattern (24 h). For the PTPRD analyses, quantitative polymerase chain reaction (qPCR) and indirect enzyme-linked immunosorbent assay (ELISA) techniques were used. To evaluate the tyrosine hydroxylase enzyme, dopamine transporter (DAT) and type 2 dopaminergic receptor, qPCR and Western Blotting techniques were used. For the quantification of iron, ferritin and transferrin, the ELISA method was used. SHRs had higher blood pressure, alterations in sleep pattern, lower expression of protein content of PTPRD, lower expression of DAT, and lower serum concentrations of ferritin. These data suggest that the behavioural, physiological, and molecular changes observed in SHRs provide a useful animal model of RLS, reinforcing the importance of this strain as an animal model of this sleep disorder.
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Affiliation(s)
- Milca Abda Morais
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, Brazil
| | - Beatriz Silva Franco
- Faculdade de Educação Física, Universidade Estadual de Campinas, Campinas, Brazil
| | | | | | | | | | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano (EOC), Lugano, Switzerland
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Kim J, Woo HW, Shin MH, Kim YM, Lim JE, Oh B, Song DS, Koh I, Kim MK. Genome-wide gene and serum ferritin interaction in the development of type 2 diabetes in adults aged 40 years or older. Nutr Metab Cardiovasc Dis 2022; 32:231-240. [PMID: 34916119 DOI: 10.1016/j.numecd.2021.09.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 09/23/2021] [Accepted: 09/23/2021] [Indexed: 11/18/2022]
Abstract
BACKGROUND AND AIMS Elevated serum ferritin is associated with incident Type 2 diabetes (T2D), but the interactions between serum ferritin and genetic factors which may improve understanding underlying mechanism in the development of T2D are still unclear. We determined the gene-ferritin interactions on the development of T2D by genome-wide gene-ferritin interaction analyses. METHODS AND RESULTS A total of 3405 participants from two prospective cohorts of community living residents were included, and the median follow-time was 3.99 years. Genome-wide gene-ferritin interactions were analyzed using the joint test with two degrees of freedom and the interaction test with one degree of freedom. There were 18 SNPs selected in the joint test. Finally, four independent variants [rs355140 (LINC00312), rs4075576 (nearby PDGFA), rs1332202 (PTPRD), and rs713157 (nearby LINC00900)] with low pairwise linkage disequilibrium (r2<0.2) and located at least 1000 kb from the index SNP showed interactions with serum ferritin level. In the association analyses between serum ferritin levels (tertiles of ferritin and ferritin status) and the incidence of T2D according to genotype, the Incidence Rate Ratios (IRRs) in the highest tertile of ferritin level (vs. the lowest tertile) were greater for participants with heterozygotes of risk alleles of each of the four SNP than IRRs for those with wild type. Compared with the normal group, the elevated ferritin group also had a higher risk of T2D for all genetic variants of risk alleles, particularly its homozygotes. CONCLUSION Serum ferritin level interacts with genetic variants (rs355140, rs4075576, rs1332202, and rs713157) in the development of T2D.
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Affiliation(s)
- Jihye Kim
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea; Institute for Health and Society, Hanyang University, Seoul, South Korea
| | - Hye Won Woo
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea; Institute for Health and Society, Hanyang University, Seoul, South Korea
| | - Min-Ho Shin
- Department of Preventive Medicine, Chonnam National University Medical School, Gwangju, South Korea
| | - Yu-Mi Kim
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea; Institute for Health and Society, Hanyang University, Seoul, South Korea
| | - Ji Eun Lim
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul, South Korea
| | - Bermseok Oh
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul, South Korea
| | - Dae Sub Song
- Division of Epidemiology and Health Index, Center for Genome Science, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Osong, South Korea
| | - Insong Koh
- Department of Physiology, College of Medicine, Hanyang University, Seoul, South Korea
| | - Mi Kyung Kim
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea; Institute for Health and Society, Hanyang University, Seoul, South Korea.
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Genetic differences in ethanol consumption: effects on iron, copper, and zinc regulation in mouse hippocampus. Biometals 2021; 34:1059-1066. [PMID: 34176056 PMCID: PMC9833394 DOI: 10.1007/s10534-021-00327-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/21/2021] [Indexed: 01/13/2023]
Abstract
One common characteristic of neurodegenerative diseases is dysregulation of iron, usually with observed increases in its concentration in various regions. Heavy alcohol consumption is believed to contribute to such iron dysregulation in the brain with accompanying dementia. To examine this effect and related genetic-based individual differences in an animal model, we subjected female mice from 12 BXD recombinant inbred strains to 16 weeks of alcohol consumption using the drinking in the dark (DID) method. Daily consumption was recorded and at the end of 16 weeks hippocampus tissues harvested. Concentrations of iron, copper and zinc were measured using X-ray fluorescence technology. The results showed that, DID increased iron overall across all strains, ranging from 3 to 68%. Copper and Zinc both decreased, ranging from 0.4-42 and 5-35% respectively. Analysis of variance revealed significant strain by treatment interactions for all three metals. Additionally, in the DID group, we observed strain differences in reduction of hippocampus mass. These findings are particularly interesting to us because high alcohol consumption in humans has been associated with neurodegeneration and dementia related to disruption of iron regulation. The findings of alcohol consumption associated decreases in copper and zinc are novel. The role of copper regulation and neurological function related to alcohol consumption is as yet largely unexplored. The role of zinc is better known as a neuromodulator in the hippocampus and appears to be protective against neurological damage. It would seem then, that the alcohol-related decrease in zinc in the hippocampus would be of concern and warrants further study.
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Bae H, Cho YW, Kim KT, Allen RP, Earley CJ. Randomized, placebo-controlled trial of ferric carboxymaltose in restless legs syndrome patients with iron deficiency anemia. Sleep Med 2021; 84:179-186. [PMID: 34157632 DOI: 10.1016/j.sleep.2021.05.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/20/2021] [Accepted: 05/31/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Intravenous ferric carboxymaltose (FCM) has been shown to be efficacious in treating restless legs syndrome (RLS) symptoms in non-anemic patients. The aim of this study was to evaluate the effectiveness of FCM in treating RLS symptoms in patients who also had an iron deficiency anemia (IDA). METHODS This is a randomized, double-blinded, placebo-controlled study. Subjects with RLS and IDA were enrolled. Subjects received an infusion of either 1500 mg FCM or placebo in Phase I. The primary outcomes were a change-from-baseline at week six on the International Restless Legs Syndrome Study Group scale (IRLS). Phase II of the study involved long-term (52 weeks) follow-up, for those who responded to treatment in the prior phase, with the potential for further treatment if symptoms returned. RESULTS We enrolled 29 RLS patients with IDA (15 FCM and 14 placebo). At week six post-infusion, FCM compared to placebo group showed significant improvement from baseline in IRLS score (-13.47 ± 7.38 vs. 1.36 ± 3.59). Among secondary outcome variables, quality of sleep showed significant improvement from baseline in the FCM group. 61% of subjects remained off RLS medications at the Phase II, week-52 endpoint. There were no serious adverse events observed in the study. CONCLUSION The study showed significant efficacy and safety of FCM 1500 mg treatment both in the short term (6 weeks) and long term (52 weeks) in RLS patients with IDA.
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Affiliation(s)
- Hyoeun Bae
- Department of Neurology, Keimyung University School of Medicine, Daegu, South Korea
| | - Yong Won Cho
- Department of Neurology, Keimyung University School of Medicine, Daegu, South Korea.
| | - Keun Tae Kim
- Department of Neurology, Keimyung University School of Medicine, Daegu, South Korea
| | - Richard P Allen
- Department of Neurology, Johns Hopkins University, Hopkins Bayview Medical Center, Baltimore, MD, USA
| | - Christopher J Earley
- Department of Neurology, Johns Hopkins University, Hopkins Bayview Medical Center, Baltimore, MD, USA
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Roy A, Earley CJ, Allen RP, Kaminsky ZA. Developing a biomarker for restless leg syndrome using genome wide DNA methylation data. Sleep Med 2020; 78:120-127. [PMID: 33422814 DOI: 10.1016/j.sleep.2020.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 12/31/2022]
Abstract
This study reports on an epigenetic biomarker for restless leg syndrome (RLS) developed using whole genome DNA methylation data. Lymphocyte-derived DNA methylation was examined in 15 subjects with and without RLS (discovery cohort). T-tests and linear regressions were used followed by a principal component analysis (PCA). The principal component model from the discovery cohort was used to predict RLS status in a peripheral blood (N = 24; including 12 cases and 12 controls) and a post-mortem neural tissue (N = 71; including 36 cases and 35 controls) replication cohort as well as iron deficiency anemia status in a publicly available dataset (N = 71, 59 cases with iron deficiency anemia, 12 controls). Using receiver-operating characteristic analysis the optimum biomarker model - that included 49 probes - predicted RLS status in the blood-based replication cohort with an area under the curve (AUC) of 87.5% (confidence interval = 71.9%-100%). In the neural tissue samples, the model predicted RLS status with an AUC of 73.4% (confidence interval = 61.5%-85.3%). An AUC of 83% was found for predictions of iron deficiency anemia. Thus, the blood-based biomarker model reported here and built with epigenome-wide data showed reasonable replicability in lymphocytes and neural tissue samples. A limitation of this study is that we could not determine the metabolic or neurobiological pathways linking epigenetic changes with RLS. Further research is needed to fine-tune this model for prospective predictions of RLS and to enable translation for clinical use.
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Affiliation(s)
- Arunima Roy
- The Royal's Institute of Mental Health Research, University of Ottawa, Canada
| | - Christopher J Earley
- Department of Neurology, The Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD, 21209, USA
| | - Richard P Allen
- Department of Neurology, The Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD, 21209, USA
| | - Zachary A Kaminsky
- The Royal's Institute of Mental Health Research, University of Ottawa, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa Ontario Canada; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Mental Health, Bloomberg School of Public Health, Baltimore, MD, USA.
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Allen RP, Earley CJ, Jones BC, Unger EL. Iron-deficiency and dopaminergic treatment effects on RLS-Like behaviors of an animal model with the brain iron deficiency pattern of the restless legs syndrome. Sleep Med 2020; 71:141-148. [PMID: 32094092 PMCID: PMC7302997 DOI: 10.1016/j.sleep.2020.01.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND Brain iron deficiency (BID), especially for the substantia nigra (SN), without peripheral iron deficiency (ID) has been well documented as a ubiquitous finding for restless legs syndrome (RLS) patients. This close association suggests the biology of RLS BID can produce RLS symptoms. Association, however, cannot establish such a direct relationship. Instead, the BID of RLS could be experimentally produced to determine if it then produces significant RLS-like biological or behavioral features. Forward genetics approach led to identification from the BXD strains the BXD40 females (BXD40f) as a putative animal model for the RLS BID. The BXD40f on an iron-sufficient diet have a lower iron in the VMB (containing the SN) during the active but not inactive period. This was not found for the other BXD strains evaluated. The BXD40f on an ID diet uniquely have even greater reduced VMB but not peripheral iron, matching the RLS BID pathophysiology. A prior report found that the BXD40f on an iron-sufficient diet had an RLS-like behavior of increased activity occurring only in the last part of the active period that was not present in the other strains without the low VMB iron. This increased activity matches the circadian pattern of symptoms in RLS patients with increased urge or drive to move in the last part of the day. This study asks first: if you decrease the VMB iron by an iron deficient diet do the RLS-like behaviors worsen; and second will the dopaminergic treatments effective for RLS also reduce the worsened RLSlike behaviors. METHODS In sum, 13 BXD40f mice post weaning were randomly assigned for 100 days to either a iron-sufficient diet (n = 6) or an ID diet (N = 7). They were then evaluated for 24-h activity in their home cage using implanted G2 EMitter telemetry device. At 3 h before the end of the active period IP doses were given every other day of either: saline (vehicle only), 12.5 mg levodopa, 25 mg levodopa, 0.5 mg quinpirole, or 1 0.0 mg quinpirole. RESULTS The ID compared to irons-sufficient diet produced earlier onset of the RLS-like behavior matching the earlier onset of symptoms with increasing severity of RLS. The dopaminergic treatments significantly reduced the RLS-like behavior. Added analyses of the RLS-like behaviors as decreased resting times showed similar results to activity increases. CONCLUSIONS These data demonstrate both that The BXD40f provide a useful animal model of RLS and also strongly support the hypothesis that the biology of RLS BID can produce RLS symptoms.
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Affiliation(s)
- Richard P Allen
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
| | - Christopher J Earley
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Byron C Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee, Memphis, TN, USA
| | - Erica L Unger
- Department of Biology, Lebanon Valley College, Annville, PA, USA
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Earley CJ, Allen RP, Jones BC, Unger EL. Developing a behavioral model of Restless Legs Syndrome utilizing mice with natural variances in ventral midbrain iron. Sleep Med 2020; 71:135-140. [PMID: 32044226 PMCID: PMC10598803 DOI: 10.1016/j.sleep.2019.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/25/2019] [Accepted: 12/13/2019] [Indexed: 01/26/2023]
Abstract
BACKGROUND The primary symptoms of Restless Legs Syndrome (RLS) are circadian-dependent, leading to increased activity or decreased rest, especially at night. The primary pathology in RLS is brain iron insufficiency despite normal systemic iron stores. Natural variances in brain and peripheral iron concentrations across recombinant inbred (RI) murine strains provide a biological model of RLS. The question is whether these RI mice strains show a behavioral analog to circadian-dependent clinical phenotype of RLS. METHODS The home cage activity of eight female RI strains was measured over a 72-h period. The ratio of the average activity in the last 2 h of the active period relative to that in the total 12-h active period (late active period activity ratio, LAPAR) was the primary outcome variable. The relation of average LAPAR scores to measures of ventral midbrain (VMB) iron was evaluated across strains in this study. RESULTS RI strain 40 (LAPAR = 1.28) and RI strain 21 (LAPAR = 1.02) were the only strains to show an increased activity in the last part of the active period. ANOVA showed the increased activity was significantly greater during the last 2 h compared to the preceding 10 h of the active phase only for the RI strain 40. Average LAPAR across the eight strains did not significantly correlate with the VMB iron content (r = -0.27, p < 0.10) but did correlate with changes in VMB iron with iron deficiency (r = 0.71, p < 0.05) and diurnal change in VMB iron (r = 0.65, p < 0.05). CONCLUSION The female RI strain 40 mice exhibited a distinct end-of-active-period behavior analogous to circadian-dependent clinical phenotype of RLS.
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Affiliation(s)
- Christopher J Earley
- Department of Neurology, The Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD, 21209, USA.
| | - Richard P Allen
- Department of Neurology, The Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD, 21209, USA
| | - Byron C Jones
- Department of Biobehavioral Health, The Pennsylvania State University, 219 Behavioral Health Building, University Park, PA, 16802, USA
| | - Erica L Unger
- Department of Nutritional Sciences, The Pennsylvania State University, 110 Chandlee Lab, University Park, PA, 16802, USA
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Zhu XY, Wu TT, Wang HM, Li X, Ni LY, Chen TJ, Qiu MY, Shen J, Liu T, Ondo WG, Wu YC. Correlates of Nonanemic Iron Deficiency in Restless Legs Syndrome. Front Neurol 2020; 11:298. [PMID: 32425874 PMCID: PMC7205016 DOI: 10.3389/fneur.2020.00298] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 03/30/2020] [Indexed: 01/23/2023] Open
Abstract
Objective: Iron deficiency anemia (IDA) is a well-known cause of secondary restless legs syndrome (RLS). Iron deficiency without anemia (IDNA) is insidious, and its association with RLS is less evaluated. We investigate prevalence and features of IDNA in a consecutive cohort of patients with RLS. Methods: We included sequential primary RLS patients and RLS patients with IDA. We also recruited age- and gender-matched healthy controls. RLS mimics and other comorbidities were carefully excluded. Results: One-hundred and ninety-six RLS patients without anemia, 26 RLS patients with IDA, and 63 controls were included. 42.3% of RLS patients without anemia had iron deficiency. Women were much more susceptible for IDNA with a relative risk of 5.51 (p < 0.0001). Women with IDNA and RLS had younger age both at interview and at RLS onset compared to women with RLS without iron deficiency (NID) (P < 0.01). IDNA RLS patients showed a tendency to higher risk of severe/very severe tiredness or sleepiness during the day as compared to NID RLS patients. Furthermore, IDNA RLS patients had longer duration of RLS (P < 0.01 in men, P < 0.05 in women) and younger age at onset (only in men, P < 0.05) compared to IDA RLS patients. Conclusion: IDNA is frequent in RLS and iron deficiency may be severe despite a normal hemoglobin level. Women are at much higher risk for IDNA, and IDNA in women presents some specific clinical features. Features of IDNA RLS are different from IDA RLS. Regular screening of peripheral iron parameters even in patients with normal blood counts is recommended for timely optimal management.
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Affiliation(s)
- Xiao-Ying Zhu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ting-Ting Wu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hong-Ming Wang
- Department of Clinical Laboratory Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuan Li
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ling-Yan Ni
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tian-Jiao Chen
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Meng-Yao Qiu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Shen
- Department of Clinical Laboratory Medicine, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Te Liu
- Geriatric Laboratory, Shanghai Geriatric Institute of Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - William G Ondo
- Department of Neurology, Methodist Neurological Institute, Weill Cornell Medical School, Houston, TX, United States
| | - Yun-Cheng Wu
- Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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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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Kell DB, Pretorius E. No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases. Biol Rev Camb Philos Soc 2018; 93:1518-1557. [PMID: 29575574 PMCID: PMC6055827 DOI: 10.1111/brv.12407] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/12/2018] [Accepted: 02/15/2018] [Indexed: 12/11/2022]
Abstract
Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.
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Affiliation(s)
- Douglas B. Kell
- School of ChemistryThe University of Manchester, 131 Princess StreetManchesterLancsM1 7DNU.K.
- The Manchester Institute of BiotechnologyThe University of Manchester, 131 Princess StreetManchesterLancsM1 7DNU.K.
- Department of Physiological SciencesStellenbosch University, Stellenbosch Private Bag X1Matieland7602South Africa
| | - Etheresia Pretorius
- Department of Physiological SciencesStellenbosch University, Stellenbosch Private Bag X1Matieland7602South Africa
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Abstract
In this contribution, we demonstrate the utility of the systems genetics-systems biology approach to the study of iron regulation while employing a comprehensive database. We describe our work in iron regulation in the brain and periphery under normal iron and iron-restricted dietary conditions in the BXD family of recombinant inbred mouse strains. Using multiple measures, we showed wide variation among the strains in the effect of being fed an iron-restricted diet for 100 days in every measure from brain and from the periphery. All data were entered into GeneNetwork ( www.genenetwork.org ), a database that contains genotypic, phenotypic, and gene expression data (Rosen et al., Methods Mol Biol 401:287-303, 2007). Using this resource, we were able to ask the following four questions concerning possible candidate genes underlying our measures: (1) what is the range of response for each of the measures? (2) Does the pattern of variability show continuous (additive genetic) or discrete (Mendelian) distribution across strains? (3) Are there genetic markers that are associated with the variability in the measures? (4) Are there genes in near the markers that contain associated allelic differences, and whose expression is related to the variability in the measures? Other questions that we could address include: (5) what is the association among the measures between the sexes? (6) What is the association among the measures, e.g., is liver iron status under the diets related to brain iron? (7) What is the relationship between our measures and other phenotypic parameters-i.e., is there an association between our brain iron measures and neurochemical phenotypes extant in the database? And finally, (8) are there gene networks that underlie single or combined measures?
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Affiliation(s)
- Byron C Jones
- Department of Genetics, Genomics, and Informatics, The University of Tennessee Health Science Center, 410J Translational Research, 71 South Manassas St., Memphis, TN, 38163, USA.
| | - Leslie C Jellen
- Department of Genetics, Genomics, and Informatics, The University of Tennessee Health Science Center, 410J Translational Research, 71 South Manassas St., Memphis, TN, 38163, USA
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Allen RP, Picchietti DL, Auerbach M, Cho YW, Connor JR, Earley CJ, Garcia-Borreguero D, Kotagal S, Manconi M, Ondo W, Ulfberg J, Winkelman JW. Evidence-based and consensus clinical practice guidelines for the iron treatment of restless legs syndrome/Willis-Ekbom disease in adults and children: an IRLSSG task force report. Sleep Med 2017; 41:27-44. [PMID: 29425576 DOI: 10.1016/j.sleep.2017.11.1126] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 11/09/2017] [Accepted: 11/13/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Brain iron deficiency has been implicated in the pathophysiology of RLS, and current RLS treatment guidelines recommend iron treatment when peripheral iron levels are low. In order to assess the evidence on the oral and intravenous (IV) iron treatment of RLS and periodic limb movement disorder (PLMD) in adults and children, the International Restless Legs Syndrome Study Group (IRLSSG) formed a task force to review these studies and provide evidence-based and consensus guidelines for the iron treatment of RLS in adults, and RLS and PLMD in children. METHODS A literature search was performed to identify papers appearing in MEDLINE from its inception to July 2016. The following inclusion criteria were used: human research on the treatment of RLS or periodic limb movements (PLM) with iron, sample size of at least five, and published in English. Two task force members independently evaluated each paper and classified the quality of evidence provided. RESULTS A total of 299 papers were identified, of these 31 papers met the inclusion criteria. Four studies in adults were given a Class I rating (one for IV iron sucrose, and three for IV ferric carboxymaltose); only Class IV studies have evaluated iron treatment in children. Ferric carboxymaltose (1000 mg) is effective for treating moderate to severe RLS in those with serum ferritin <300 μg/l and could be used as first-line treatment for RLS in adults. Oral iron (65 mg elemental iron) is possibly effective for treating RLS in those with serum ferritin ≤75 μg/l. There is insufficient evidence to make conclusions on the efficacy of oral iron or IV iron in children. CONCLUSIONS Consensus recommendations based on clinical practice are presented, including when to use oral iron or IV iron, and recommendations on repeated iron treatments. New iron treatment algorithms, based on evidence and consensus opinion have been developed.
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Affiliation(s)
- Richard P Allen
- Department of Neurology, Johns Hopkins University, Hopkins Bayview Medical Center, Baltimore, MD, USA.
| | - Daniel L Picchietti
- University of Illinois College of Medicine at Urbana-Champaign and Carle Foundation Hospital, Urbana, IL, USA
| | - Michael Auerbach
- Department of Medicine, Georgetown University, Washington DC, USA
| | - Yong Won Cho
- Department of Neurology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Republic of Korea
| | - James R Connor
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey PA, USA
| | - Christopher J Earley
- Department of Neurology, Johns Hopkins University, Hopkins Bayview Medical Center, Baltimore, MD, USA
| | | | - Suresh Kotagal
- Department of Neurology and the Center for Sleep Medicine, Mayo Clinic, Rochester, MN, USA
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital of Lugano, Lugano, Switzerland
| | - William Ondo
- Methodist Neurological Institute, Weill Cornell Medical School Houston, TX, USA
| | - Jan Ulfberg
- Sleep Disorders Department, Capio Health Center, Örebro, Sweden
| | - John W Winkelman
- Departments of Psychiatry and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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13
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Struebing FL, Lee RK, Williams RW, Geisert EE. Genetic Networks in Mouse Retinal Ganglion Cells. Front Genet 2016; 7:169. [PMID: 27733864 PMCID: PMC5039302 DOI: 10.3389/fgene.2016.00169] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/06/2016] [Indexed: 01/17/2023] Open
Abstract
Retinal ganglion cells (RGCs) are the output neuron of the eye, transmitting visual information from the retina through the optic nerve to the brain. The importance of RGCs for vision is demonstrated in blinding diseases where RGCs are lost, such as in glaucoma or after optic nerve injury. In the present study, we hypothesize that normal RGC function is transcriptionally regulated. To test our hypothesis, we examine large retinal expression microarray datasets from recombinant inbred mouse strains in GeneNetwork and define transcriptional networks of RGCs and their subtypes. Two major and functionally distinct transcriptional networks centering around Thy1 and Tubb3 (Class III beta-tubulin) were identified. Each network is independently regulated and modulated by unique genomic loci. Meta-analysis of publically available data confirms that RGC subtypes are differentially susceptible to death, with alpha-RGCs and intrinsically photosensitive RGCs (ipRGCs) being less sensitive to cell death than other RGC subtypes in a mouse model of glaucoma.
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Affiliation(s)
- Felix L Struebing
- Department of Ophthalmology, Emory University School of Medicine Atlanta, GA, USA
| | - Richard K Lee
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine Miami, FL, USA
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center Memphis, TN, USA
| | - Eldon E Geisert
- Department of Ophthalmology, Emory University School of Medicine Atlanta, GA, USA
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14
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Abstract
Restless legs syndrome (RLS) is a complex disorder that involves sensory and motor systems. The major pathophysiology of RLS is low iron concentration in the substantia nigra containing the cell bodies of dopamine neurons that project to the striatum, an area that is crucial for modulating movement. People who have RLS often present with normal iron values outside the brain; recent studies implicate several genes are involved in the syndrome. Like most complex diseases, animal models usually do not faithfully capture the full phenotypic spectrum of "disease," which is a uniquely human construct. Nonetheless, animal models have proven useful in helping to unravel the complex pathophysiology of diseases such as RLS and suggesting novel treatment paradigms. For example, hypothesis-independent genome-wide association studies (GWAS) have identified several genes as increasing the risk for RLS, including BTBD9. Independently, the murine homolog Btbd9 was identified as a candidate gene for iron regulation in the midbrain in mice. The relevance of the phenotype of another of the GWAS identified genes, MEIS1, has also been explored. The role of Btbd9 in iron regulation and RLS-like behaviors has been further evaluated in mice carrying a null mutation of the gene and in fruit flies when the BTBD9 protein is degraded. The BTBD9 and MEIS1 stories originate from human GWAS research, supported by work in a genetic reference population of mice (forward genetics) and further verified in mice, fish flies, and worms. Finally, the role of genetics is further supported by an inbred mouse strain that displays many of the phenotypic characteristics of RLS. The role of animal models of RLS phenotypes is also extended to include periodic limb movements.
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15
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Ndfip2 is a potential regulator of the iron transporter DMT1 in the liver. Sci Rep 2016; 6:24045. [PMID: 27048792 PMCID: PMC4822147 DOI: 10.1038/srep24045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/21/2016] [Indexed: 02/07/2023] Open
Abstract
The regulation of divalent metal ion transporter DMT1, the primary non-heme iron importer in mammals, is critical for maintaining iron homeostasis. Previously we identified ubiquitin-dependent regulation of DMT1 involving the Nedd4 family of ubiquitin ligases and the Ndfip1 and Ndfip2 adaptors. We also established the in vivo function of Ndfip1 in the regulation of DMT1 in the duodenum of mice. Here we have studied the function of Ndfip2 using Ndfip2-deficient mice. The DMT1 protein levels in the duodenum were comparable in wild type and Ndfip2−/− mice, as was the transport activity of isolated enterocytes. A complete blood examination showed no significant differences between wild type and Ndfip2−/− mice in any of the hematological parameters measured. However, when fed a low iron diet, female Ndfip2−/− mice showed a decrease in liver iron content, although they maintained normal serum iron levels and transferrin saturation, compared to wild type female mice that showed a reduction in serum iron and transferrin saturation. Ndfip2−/− female mice also showed an increase in DMT1 expression in the liver, with no change in male mice. We suggest that Ndfip2 controls DMT1 in the liver with female mice showing a greater response to altered dietary iron than the male mice.
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16
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O'Connell KE, Mikkola AM, Stepanek AM, Vernet A, Hall CD, Sun CC, Yildirim E, Staropoli JF, Lee JT, Brown DE. Practical murine hematopathology: a comparative review and implications for research. Comp Med 2015; 65:96-113. [PMID: 25926395 PMCID: PMC4408895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 11/09/2014] [Accepted: 12/25/2014] [Indexed: 06/04/2023]
Abstract
Hematologic parameters are important markers of disease in human and veterinary medicine. Biomedical research has benefited from mouse models that recapitulate such disease, thus expanding knowledge of pathogenetic mechanisms and investigative therapies that translate across species. Mice in health have many notable hematologic differences from humans and other veterinary species, including smaller erythrocytes, higher percentage of circulating reticulocytes or polychromasia, lower peripheral blood neutrophil and higher peripheral blood and bone marrow lymphocyte percentages, variable leukocyte morphologies, physiologic splenic hematopoiesis and iron storage, and more numerous and shorter-lived erythrocytes and platelets. For accurate and complete hematologic analyses of disease and response to investigative therapeutic interventions, these differences and the unique features of murine hematopathology must be understood. Here we review murine hematology and hematopathology for practical application to translational investigation.
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Affiliation(s)
- Karyn E O'Connell
- Department of Comparative Pathology, New England Primate Research Center, Harvard Medical School, Southboro, Massachusetts, USA
| | - Amy M Mikkola
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Aaron M Stepanek
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Public Health and Professional Degree Program, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Andyna Vernet
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, Massachusetts, USA
| | - Christopher D Hall
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Chia C Sun
- Program in Anemia Signaling Research, Nephrology Division, Massachusetts General Hospital, Boston, Massachusetts, USA; Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Boston, Massachusetts, Cellular and Translational Immunology, EMD Serono Research and Development Institute, Billerica, Massachusetts, USA
| | - Eda Yildirim
- Department of Molecular Biology, Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - John F Staropoli
- Molecular Neurogenetics Unit, Center for Human Genetic Research, Department of Pathology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA; Biogen Idec, Cambridge, Massachusetts, USA
| | - Jeannie T Lee
- Department of Molecular Biology, Center for Human Genetic Research, Department of Pathology, Harvard Medical School, Howard Hughes Medical Institute, Harvard Medical School, Massachusetts General Hospital, Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Diane E Brown
- Center for Comparative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Pathology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA.
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17
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Unger EL, Bianco LE, Jones BC, Allen RP, Earley CJ. Low brain iron effects and reversibility on striatal dopamine dynamics. Exp Neurol 2014; 261:462-8. [PMID: 24999026 DOI: 10.1016/j.expneurol.2014.06.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 06/09/2014] [Accepted: 06/26/2014] [Indexed: 11/18/2022]
Abstract
Iron deficiency (ID) in rodents leads to decreased ventral midbrain (VMB) iron concentrations and to changes in the dopamine (DA) system that mimic many of the dopaminergic changes seen in RLS patient where low substantia nigra iron is a known pathology of the disease. The ID-rodent model, therefore, has been used to explore the effects that low VMB iron can have on striatal DA dynamics with the hopes of better understanding the nature of iron-dopamine interaction in Restless Legs Syndrome (RLS). Using a post-weaning, diet-induced, ID condition in rats, the No-Net-Flux microdialysis technique was used to examine the effect of ID on striatal DA dynamics and it reversibility with acute infusion of physiological concentrations of iron into the VMB. This study replicated prior findings by showing that the ID condition is associated with increased extracellular striatal DA, reduced striatal DA uptake, and blunted DA-2-receptor-agonist feedback enhancement of striatal DA uptake. Despite the increase in extracellular striatal DA, intracellular striatal DA, as determined in tissue homogenates, was decrease in the ID rat. The study's key finding was that an infusion of physiological concentrations of iron into the VMB reversed the ID-induced increase in extracellular striatal DA and the ID-induced decrease in intracellular striatal DA but had no effect on the ID-induced changes in DA uptake or on the blunted DA-uptake response to quinpirole. In summary, the ID-rodent model provides highly reproducible changes in striatal DA dynamics that remarkably parallel dopaminergic changes seen in RLS patients. Some but not all of these ID-induced changes in striatal DA dynamics were reversible with physiological increases in VMB iron. The small changes in VMB iron induced by iron infusion likely represent biologically relevant changes in the non-transferrin-bound labile iron pool and may mimic circadian-dependent changes that have been found in VBM extracellular iron.
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Affiliation(s)
- Erica L Unger
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Laura E Bianco
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Byron C Jones
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA 16802, USA
| | - Richard P Allen
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
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18
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Waldvogel-Abramowski S, Waeber G, Gassner C, Buser A, Frey BM, Favrat B, Tissot JD. Physiology of iron metabolism. Transfus Med Hemother 2014; 41:213-21. [PMID: 25053935 DOI: 10.1159/000362888] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 12/04/2013] [Indexed: 12/12/2022] Open
Abstract
A revolution occurred during the last decade in the comprehension of the physiology as well as in the physiopathology of iron metabolism. The purpose of this review is to summarize the recent knowledge that has accumulated, allowing a better comprehension of the mechanisms implicated in iron homeostasis. Iron metabolism is very fine tuned. The free molecule is very toxic; therefore, complex regulatory mechanisms have been developed in mammalian to insure adequate intestinal absorption, transportation, utilization, and elimination. 'Ironomics' certainly will be the future of the understanding of genes as well as of the protein-protein interactions involved in iron metabolism.
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Affiliation(s)
| | - Gérard Waeber
- Service de médecine interne, CHUV, Lausanne, Switzerland
| | | | | | | | - Bernard Favrat
- Department of Ambulatory Care and Community Medicine, Lausanne, Switzerland
| | - Jean-Daniel Tissot
- Service régional vaudois de transfusion sanguine, Epalinges, Switzerland
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19
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Jellen LC, Lu L, Wang X, Unger EL, Earley CJ, Allen RP, Williams RW, Jones BC. Iron deficiency alters expression of dopamine-related genes in the ventral midbrain in mice. Neuroscience 2013; 252:13-23. [PMID: 23911809 DOI: 10.1016/j.neuroscience.2013.07.058] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/24/2013] [Accepted: 07/24/2013] [Indexed: 12/01/2022]
Abstract
A clear link exists between iron deficiency (ID) and nigrostriatal dopamine malfunction. This link appears to play an important role in at least restless legs syndrome (RLS) if not several other neurological diseases. Yet, the underlying mechanisms remain unclear. The effects of ID on gene expression in the brain have not been studied extensively. Here, to better understand how exactly ID alters dopamine functioning, we investigated the effects of ID on gene expression in the brain, seeking to identify any potential transcription-based mechanisms. We used six strains of recombinant inbred mice (BXD type) known to differ in susceptibility to ID in the brain. Upon weaning, we subjected mice from each strain to either an iron-deficient or iron-adequate diet. After 100 days of dietary treatment, we measured the effects of ID on gene expression in the ventral midbrain, a region containing the substantia nigra. The substantia nigra is the base of the nigrostriatal dopamine pathway and a region particularly affected by iron loss in RLS. We screened for ID-induced changes in expression, including changes in that of both iron-regulating and dopamine-related genes. Results revealed a number of expression changes occurring in ID, with large strain-dependent differences in the genes involved and number of expression changes occurring. In terms of dopamine-related genes, results revealed ID-induced expression changes in three genes with direct ties to nigrostriatal dopamine functioning, two of which have never before been implicated in an iron-dopamine pathway. These were stromal cell-derived factor 1 (Cxcl12, or SDF-1), a ferritin regulator and potent dopamine neuromodulator, and hemoglobin, beta adult chain 1 (Hbb-b1), a gene recently shown to play a functional role in dopaminergic neurons. The extent of up-regulation of these genes varied by strain. This work not only demonstrates a wide genetic variation in the transcriptional response to ID in the brain, but also reveals two novel biochemical pathways by which iron may potentially alter dopamine function.
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Affiliation(s)
- L C Jellen
- Neuroscience Institute, The Pennsylvania State University, University Park, PA, USA
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20
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Brown DE, Libby SJ, Moreland SM, McCoy MW, Brabb T, Stepanek A, Fang FC, Detweiler CS. Salmonella enterica causes more severe inflammatory disease in C57/BL6 Nramp1G169 mice than Sv129S6 mice. Vet Pathol 2013; 50:867-76. [PMID: 23446432 DOI: 10.1177/0300985813478213] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) causes systemic inflammatory disease in mice by colonizing cells of the mononuclear leukocyte lineage. Mouse strains resistant to S. Typhimurium, including Sv129S6, have an intact Nramp1 (Slc11a1) allele and survive acute infection, whereas C57/BL6 mice, homozygous for a mutant Nramp1 allele, Nramp1(G169D) , develop lethal infections. Restoration of Nramp1 (C57/BL6 Nramp1(G169) ) reestablishes resistance to S. Typhimurium; mice survive at least 3 to 4 weeks postinfection. Since many transgenic mouse strains are on a C57/BL6 genetic background, C57/BL6 Nramp1(G169) mice provide a model to examine host genetic determinants of resistance to infection. To further evaluate host immune response to S. Typhimurium, we performed comparative analyses of Sv129S6 and C57/BL6 Nramp1(G169) mice 3 weeks following oral S. Typhimurium infection. C57/BL6 Nramp1(G169) mice developed more severe inflammatory disease with splenic bacterial counts 1000-fold higher than Sv129S6 mice and relatively greater splenomegaly and blood neutrophil and monocyte counts. Infected C57/BL6 Nramp1(G169) mice developed higher proinflammatory serum cytokine and chemokine responses (interferon-γ, tumor necrosis factor-α, interleukin [IL]-1β, and IL-2 and monocyte chemotactic protein-1 and chemokine [C-X-C motif] ligand 1, respectively) and marked decreases in anti-inflammatory serum cytokine concentrations (IL-10, IL-4) compared with Sv129S6 mice postinfection. Splenic dendritic cells and macrophages in infected compared with control mice increased to a greater extent in C57/BL6 Nramp1(G169) mice than in Sv129S6 mice. Overall, data show that despite the Nramp1 gene present in both strains, C57/BL6 Nramp1(G169) mice develop more severe, Th1-skewed, acute inflammatory responses to S. Typhimurium infection compared with Sv129S6 mice. Both strains are suitable model systems for studying inflammation in the context of adaptive immunity.
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Affiliation(s)
- D E Brown
- Massachusetts General Hospital, Harvard Medical School, 149 13th St, Boston, MA 02129, USA.
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21
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Jellen LC, Unger EL, Lu L, Williams RW, Rousseau S, Wang X, Earley CJ, Allen RP, Miles MF, Jones BC. Systems genetic analysis of the effects of iron deficiency in mouse brain. Neurogenetics 2012; 13:147-57. [PMID: 22457016 DOI: 10.1007/s10048-012-0321-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 03/10/2012] [Indexed: 01/16/2023]
Abstract
Iron regulation in the brain is both necessary and highly complex. Too little or too much iron can compromise neurological function, yet we still do not know all of the regulatory processes. In our research, we seek to identify genes and gene networks underlying individual differences in brain iron regulation. To this end, we fed mice from 20+ inbred strains a diet low in iron from weaning to 4 months of age. At sacrifice, we measured iron content in the ventral midbrain (VMB). The VMB contains the substantia nigra, a region particularly vulnerable to iron imbalance. The results showed high, inter-strain variability in dietary iron reduction, from almost no loss to more than 40 % vs. control. When we performed quantitative trait loci (QTL) analysis, we observed a significant area on chromosome 2. Within this QTL, we selected glial high-affinity glutamate transporter 1 (Glt1) as the leading candidate. Expression of this gene is both correlated with VMB iron and is also cis-modulated by local sequence variants that segregate in the BXD family. VMB expression differences of Glt1 in six strains covary with differential susceptibility to VMB iron loss.
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Affiliation(s)
- Leslie C Jellen
- Intercollege Graduate Degree Program in Neuroscience, The Pennsylvania State University, University Park, PA 16802, USA
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