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2.
Endocr Connect ; 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32348957

RESUMO

Multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant disorder caused by MEN1 germline mutations, is characterised by parathyroid, pancreatic and pituitary tumours. MEN1 mutations also cause familial isolated primary hyperparathyroidism (FIHP), a milder condition causing hyperparathyroidism only. Identical mutations can cause either MEN1 or FIHP in different families, thereby implicating a role for genetic modifiers in altering phenotypic expression of tumours. We therefore investigated the effects of genetic background and potential for genetic modifiers on tumour development in adult Men1+/- mice, which develop tumours of the parathyroids, pancreatic islets, anterior pituitary, adrenal cortex, and gonads, that had been backcrossed to generate C57BL/6 and 129S6/SvEv congenic strains. A total of 275 Men1+/- mice, aged 5-26 months were macroscopically studied, and this revealed that genetic background significantly influenced the development of pituitary, adrenal and ovarian tumours, which occurred in mice over 12 months of age and more frequently in C57BL/6 females, 129S6/SvEv males, and 129S6/SvEv females, respectively. Moreover, pituitary and adrenal tumours developed earlier, in C57BL/6 males and 129S6/SvEv females, respectively, and pancreatic and testicular tumours developed earlier in 129S6/SvEv males. Furthermore, glucagon-positive staining pancreatic tumours occurred more frequently in 129S6/SvEv Men1+/- mice. Whole genome sequence analysis of 129S6/SvEv and C57BL/6 Men1+/- mice revealed >54,000 different variants in >300 genes. These included, Coq7, Dmpk, Ccne2, Kras, Wnt2b, Il3ra, and Tnfrsf10a, and qRT-PCR analysis revealed that Kras was significantly higher in pituitaries of male 129S6/SvEv mice. Thus, our results demonstrate that Kras and other genes could represent possible genetic modifiers of Men1.

3.
Genetics ; 214(2): 467-477, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31836612

RESUMO

XY C57BL/6J (B6) mice harboring a Mus musculus domesticus-type Y chromosome (Y POS ), known as B6.Y POS mice, commonly undergo gonadal sex reversal and develop as phenotypic females. In a minority of cases, B6.Y POS males are identified and a proportion of these are fertile. This phenotypic variability on a congenic B6 background has puzzled geneticists for decades. Recently, a B6.Y POS colony was shown to carry a non-B6-derived region of chromosome 11 that protected against B6.Y POS sex reversal. Here. we show that a B6.Y POS colony bred and archived at the MRC Harwell Institute lacks the chromosome 11 modifier but instead harbors an ∼37 Mb region containing non-B6-derived segments on chromosome 13. This region, which we call Mod13, protects against B6.Y POS sex reversal in a proportion of heterozygous animals through its positive and negative effects on gene expression during primary sex determination. We discuss Mod13's influence on the testis determination process and its possible origin in light of sequence similarities to that region in other mouse genomes. Our data reveal that the B6.Y POS sex reversal phenomenon is genetically complex and the explanation of observed phenotypic variability is likely dependent on the breeding history of any local colony.

4.
Curr Protoc Mouse Biol ; 9(3): e64, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31532925

RESUMO

Genetically modified mice are an essential tool for modeling disease-causing mechanisms and discovering gene function. SNP genotyping was traditionally used to associate candidate regions with traits in the mouse, but failed to reveal novel variants without further targeted sequencing. Using a robust set of computational protocols, we present a platform to enable scientists to detect variants arising from whole-genome and exome sequencing experiments. This article guides researchers on aligning reads to the mouse genome, quality-assurance strategies, mutation discovery, comparing mutations to previously discovered mouse SNPs, and the annotation of novel variants, in order to predict mutation consequences on the protein level. Challenges unique to the mouse are discussed, and two protocols use self-contained containers to maintain version control and allow users to adapt our approach to new techniques by upgrading container versions. Our protocols are suited for servers or office workstations and are usable by non-bioinformatics specialists. © 2019 by John Wiley & Sons, Inc.


Assuntos
Biologia Computacional/métodos , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Camundongos/genética , Mutação , Animais , Análise de Sequência de DNA , Sequenciamento Completo do Genoma
6.
EMBO Mol Med ; 11(9): e10288, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31448880

RESUMO

Hearing relies on mechanically gated ion channels present in the actin-rich stereocilia bundles at the apical surface of cochlear hair cells. Our knowledge of the mechanisms underlying the formation and maintenance of the sound-receptive structure is limited. Utilizing a large-scale forward genetic screen in mice, genome mapping and gene complementation tests, we identified Clrn2 as a new deafness gene. The Clrn2clarinet/clarinet mice (p.Trp4* mutation) exhibit a progressive, early-onset hearing loss, with no overt retinal deficits. Utilizing data from the UK Biobank study, we could show that CLRN2 is involved in human non-syndromic progressive hearing loss. Our in-depth morphological, molecular and functional investigations establish that while it is not required for initial formation of cochlear sensory hair cell stereocilia bundles, clarin-2 is critical for maintaining normal bundle integrity and functioning. In the differentiating hair bundles, lack of clarin-2 leads to loss of mechano-electrical transduction, followed by selective progressive loss of the transducing stereocilia. Together, our findings demonstrate a key role for clarin-2 in mammalian hearing, providing insights into the interplay between mechano-electrical transduction and stereocilia maintenance.

7.
Am J Perinatol ; 36(11): 1097-1105, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30822800

RESUMO

OBJECTIVE: Our objective was to evaluate the efficacy of perioperative multimodal pain management in reducing opioid use after elective cesarean delivery (CD). STUDY DESIGN: A single-center, double-blinded, placebo-controlled randomized trial of women undergoing elective CD. Participants were allocated 1:1 to receive the multimodal protocol or matching placebos. The multimodal protocol consisted of a preoperative dose of intravenous acetaminophen, preincision injection of subcutaneous bupivacaine, and intraoperative injection of intramuscular ketorolac. Primary outcome was total opioid intake at 48 hours postoperatively. Secondary outcomes were pain scores, time to first opioid intake, neonatal outcomes, and total outpatient opioid intake on postoperative day (POD) 7. Data were analyzed using parametric and nonparametric tests and quantile regression as appropriate. RESULTS: A total of 242 women were screened with 120 randomized, 60 to the multimodal group and 60 to control group. There was no significant difference in the primary outcome of opioid use nor in the secondary outcomes. Smokers and patients with a history of drug use had higher median postoperative opiate use and earlier administration. On POD 7, only 40% of prescribed opioids had been used, and there was no difference between the groups. CONCLUSION: This perioperative multimodal pain regimen did not reduce opioid use in 48 hours after CD. Patients who smoke or with a history of drug use required more opioids in the postoperative period. Providers significantly overprescribed opioids after CD.

8.
J Bone Miner Res ; 34(7): 1324-1335, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30830987

RESUMO

Nephrolithiasis (NL) and nephrocalcinosis (NC), which comprise renal calcification of the collecting system and parenchyma, respectively, have a multifactorial etiology with environmental and genetic determinants and affect ∼10% of adults by age 70 years. Studies of families with hereditary NL and NC have identified >30 causative genes that have increased our understanding of extracellular calcium homeostasis and renal tubular transport of calcium. However, these account for <20% of the likely genes that are involved, and to identify novel genes for renal calcification disorders, we investigated 1745 12-month-old progeny from a male mouse that had been treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) for radiological renal opacities. This identified a male mouse with renal calcification that was inherited as an autosomal dominant trait with >80% penetrance in 152 progeny. The calcification consisted of calcium phosphate deposits in the renal papillae and was associated with the presence of the urinary macromolecules osteopontin and Tamm-Horsfall protein, which are features found in Randall's plaques of patients with NC. Genome-wide mapping located the disease locus to a ∼30 Mbp region on chromosome 17A3.3-B3 and whole-exome sequence analysis identified a heterozygous mutation, resulting in a missense substitution (Met149Thr, M149T), in the bromodomain-containing protein 4 (BRD4). The mutant heterozygous (Brd4+/M149T ) mice, when compared with wild-type (Brd4+/+ ) mice, were normocalcemic and normophosphatemic, with normal urinary excretions of calcium and phosphate, and had normal bone turnover markers. BRD4 plays a critical role in histone modification and gene transcription, and cDNA expression profiling, using kidneys from Brd4+/M149T and Brd4+/+ mice, revealed differential expression of genes involved in vitamin D metabolism, cell differentiation, and apoptosis. Kidneys from Brd4+/M149T mice also had increased apoptosis at sites of calcification within the renal papillae. Thus, our studies have established a mouse model, due to a Brd4 Met149Thr mutation, for inherited NC. © 2019 American Society for Bone and Mineral Research.

9.
J Bone Miner Res ; 34(3): 497-507, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30395686

RESUMO

Renal calcification (RCALC) resulting in nephrolithiasis and nephrocalcinosis, which affects ∼10% of adults by 70 years of age, involves environmental and genetic etiologies. Thus, nephrolithiasis and nephrocalcinosis occurs as an inherited disorder in ∼65% of patients, and may be associated with endocrine and metabolic disorders including: primary hyperparathyroidism, hypercalciuria, renal tubular acidosis, cystinuria, and hyperoxaluria. Investigations of families with nephrolithiasis and nephrocalcinosis have identified some causative genes, but further progress is limited as large families are unavailable for genetic studies. We therefore embarked on establishing mouse models for hereditary nephrolithiasis and nephrocalcinosis by performing abdominal X-rays to identify renal opacities in N-ethyl-N-nitrosourea (ENU)-mutagenized mice. This identified a mouse with RCALC inherited as an autosomal dominant trait, designated RCALC type 2 (RCALC2). Genomewide mapping located the Rcalc2 locus to a ∼16-Mbp region on chromosome 11D-E2 and whole-exome sequence analysis identified a heterozygous mutation in the DNA polymerase gamma-2, accessory subunit (Polg2) resulting in a nonsense mutation, Tyr265Stop (Y265X), which co-segregated with RCALC2. Kidneys of mutant mice (Polg2+ / Y265X ) had lower POLG2 mRNA and protein expression, compared to wild-type littermates (Polg2+/+ ). The Polg2+/Y265X and Polg2+ / + mice had similar plasma concentrations of sodium, potassium, calcium, phosphate, chloride, urea, creatinine, glucose, and alkaline phosphatase activity; and similar urinary fractional excretion of calcium, phosphate, oxalate, and protein. Polg2 encodes the minor subunit of the mitochondrial DNA (mtDNA) polymerase and the mtDNA content in Polg2+ / Y265X kidneys was reduced compared to Polg2+/+ mice, and cDNA expression profiling revealed differential expression of 26 genes involved in several biological processes including mitochondrial DNA function, apoptosis, and ubiquitination, the complement pathway, and inflammatory pathways. In addition, plasma of Polg2+ / Y265X mice, compared to Polg2+ / + littermates had higher levels of reactive oxygen species. Thus, our studies have identified a mutant mouse model for inherited renal calcification associated with a Polg2 nonsense mutation. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc.

10.
Cell Rep ; 25(12): 3315-3328.e6, 2018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30566859

RESUMO

Mutations in genes essential for mitochondrial function have pleiotropic effects. The mechanisms underlying these traits yield insights into metabolic homeostasis and potential therapies. Here we report the characterization of a mouse model harboring a mutation in the tryptophanyl-tRNA synthetase 2 (Wars2) gene, encoding the mitochondrial-localized WARS2 protein. This hypomorphic allele causes progressive tissue-specific pathologies, including hearing loss, reduced adiposity, adipose tissue dysfunction, and hypertrophic cardiomyopathy. We demonstrate the tissue heterogeneity arises as a result of variable activation of the integrated stress response (ISR) pathway and the ability of certain tissues to respond to impaired mitochondrial translation. Many of the systemic metabolic effects are likely mediated through elevated fibroblast growth factor 21 (FGF21) following activation of the ISR in certain tissues. These findings demonstrate the potential pleiotropy associated with Wars2 mutations in patients.


Assuntos
Especificidade de Órgãos , Fosforilação Oxidativa , Estresse Fisiológico , Triptofano-tRNA Ligase/genética , Tecido Adiposo Marrom/patologia , Tecido Adiposo Branco/patologia , Adiposidade , Alelos , Processamento Alternativo/genética , Animais , Sequência de Bases , Peso Corporal , Encéfalo/patologia , Cardiomiopatia Hipertrófica/sangue , Cardiomiopatia Hipertrófica/complicações , Cardiomiopatia Hipertrófica/fisiopatologia , Modelos Animais de Doenças , Transporte de Elétrons , Potenciais Evocados Auditivos do Tronco Encefálico , Éxons/genética , Fatores de Crescimento de Fibroblastos/sangue , Fibroblastos/metabolismo , Perda Auditiva/sangue , Perda Auditiva/complicações , Perda Auditiva/genética , Perda Auditiva/fisiopatologia , Camundongos , Camundongos Mutantes , Músculo Esquelético/metabolismo , Mutação/genética , Biogênese de Organelas , Triptofano-tRNA Ligase/metabolismo , Regulação para Cima
11.
Environ Model Softw ; 109: 368-379, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30505208

RESUMO

Decision-support tools (DSTs) are often produced from collaborations between technical experts and stakeholders to address environmental problems and inform decision making. Studies in the past two decades have provided key insights on the use of DSTs and the importance of bidirectional information flows among technical experts and stakeholders - a process that is variously referred to as co-production, participatory modeling, structured decision making, or simply stakeholder participation. Many of these studies have elicited foundational insights for the broad field of water resources management; however, questions remain on approaches for balancing co-production with uncertainty specifically for watershed modeling decision support tools. In this paper, we outline a simple conceptual model that focuses on the DST development process. Then, using watershed modeling case studies found in the literature, we discuss successful outcomes and challenges associated with embedding various forms of co-production into each stage of the conceptual model. We also emphasize the "3 Cs" (i.e., characterization, calculation, communication) of uncertainty and provide evidence-based suggestions for their incorporation in the watershed modeling DST development process. We conclude by presenting a list of best practices derived from current literature for achieving effective and robust watershed modeling decision-support tools.

12.
Dis Model Mech ; 11(12)2018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30478029

RESUMO

Isocitrate dehydrogenase (IDH) is an enzyme required for the production of α-ketoglutarate from isocitrate. IDH3 generates the NADH used in the mitochondria for ATP production, and is a tetramer made up of two α, one ß and one γ subunit. Loss-of-function and missense mutations in both IDH3A and IDH3B have previously been implicated in families exhibiting retinal degeneration. Using mouse models, we investigated the role of IDH3 in retinal disease and mitochondrial function. We identified mice with late-onset retinal degeneration in a screen of ageing mice carrying an ENU-induced mutation, E229K, in Idh3a Mice homozygous for this mutation exhibit signs of retinal stress, indicated by GFAP staining, as early as 3 months, but no other tissues appear to be affected. We produced a knockout of Idh3a and found that homozygous mice do not survive past early embryogenesis. Idh3a-/E229K compound heterozygous mutants exhibit a more severe retinal degeneration compared with Idh3aE229K/E229K homozygous mutants. Analysis of mitochondrial function in mutant cell lines highlighted a reduction in mitochondrial maximal respiration and reserve capacity levels in both Idh3aE229K/E229K and Idh3a-/E229K cells. Loss-of-function Idh3b mutants do not exhibit the same retinal degeneration phenotype, with no signs of retinal stress or reduction in mitochondrial respiration. It has previously been reported that the retina operates with a limited mitochondrial reserve capacity and we suggest that this, in combination with the reduced reserve capacity in mutants, explains the degenerative phenotype observed in Idh3a mutant mice.This article has an associated First Person interview with the first author of the paper.


Assuntos
Isocitrato Desidrogenase/genética , Mitocôndrias/patologia , Mutação/genética , Degeneração Retiniana/genética , Degeneração Retiniana/fisiopatologia , Animais , Fibroblastos/metabolismo , Genótipo , Isocitrato Desidrogenase/metabolismo , Mutação com Perda de Função/genética , Camundongos , Mutação de Sentido Incorreto/genética , Fenótipo , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras de Vertebrados/patologia , Retina/patologia , Retina/fisiopatologia
13.
JBMR Plus ; 2(3): 154-163, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-30283900

RESUMO

Kyphosis and scoliosis are common spinal disorders that occur as part of complex syndromes or as nonsyndromic, idiopathic diseases. Familial and twin studies implicate genetic involvement, although the causative genes for idiopathic kyphoscoliosis remain to be identified. To facilitate these studies, we investigated progeny of mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) and assessed them for morphological and radiographic abnormalities. This identified a mouse with kyphoscoliosis due to fused lumbar vertebrae, which was inherited as an autosomal dominant trait; the phenotype was designated as hereditary vertebral fusion (HVF) and the locus as Hvf. Micro-computed tomography (µCT) analysis confirmed the occurrence of nonsyndromic kyphoscoliosis due to fusion of lumbar vertebrae in HVF mice, consistent with a pattern of blocked vertebrae due to failure of segmentation. µCT scans also showed the lumbar vertebral column of HVF mice to have generalized disc narrowing, displacement with compression of the neural spine, and distorted transverse processes. Histology of lumbar vertebrae revealed HVF mice to have irregularly shaped vertebral bodies and displacement of intervertebral discs and ossification centers. Genetic mapping using a panel of single nucleotide polymorphic (SNP) loci arranged in chromosome sets and DNA samples from 23 HVF (eight males and 15 females) mice, localized Hvf to chromosome 4A3 and within a 5-megabase (Mb) region containing nine protein coding genes, two processed transcripts, three microRNAs, five small nuclear RNAs, three large intergenic noncoding RNAs, and 24 pseudogenes. However, genome sequence analysis in this interval did not identify any abnormalities in the coding exons, or exon-intron boundaries of any of these genes. Thus, our studies have established a mouse model for a monogenic form of nonsyndromic kyphoscoliosis due to fusion of lumbar vertebrae, and further identification of the underlying genetic defect will help elucidate the molecular mechanisms involved in kyphoscoliosis. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

14.
Conserv Genet ; 19(4): 995-1005, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30100824

RESUMO

The International Mouse Phenotyping Consortium (IMPC) is building a catalogue of mammalian gene function by producing and phenotyping a knockout mouse line for every protein-coding gene. To date, the IMPC has generated and characterised 5186 mutant lines. One-third of the lines have been found to be non-viable and over 300 new mouse models of human disease have been identified thus far. While current bioinformatics efforts are focused on translating results to better understand human disease processes, IMPC data also aids understanding genetic function and processes in other species. Here we show, using gorilla genomic data, how genes essential to development in mice can be used to help assess the potentially deleterious impact of gene variants in other species. This type of analyses could be used to select optimal breeders in endangered species to maintain or increase fitness and avoid variants associated to impaired-health phenotypes or loss-of-function mutations in genes of critical importance. We also show, using selected examples from various mammal species, how IMPC data can aid in the identification of candidate genes for studying a condition of interest, deliver information about the mechanisms involved, or support predictions for the function of genes that may play a role in adaptation. With genotyping costs decreasing and the continued improvements of bioinformatics tools, the analyses we demonstrate can be routinely applied.

16.
BMC Biol ; 16(1): 70, 2018 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-29925374

RESUMO

BACKGROUND: Recent advances in clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) genome editing have led to the use of long single-stranded DNA (lssDNA) molecules for generating conditional mutations. However, there is still limited available data on the efficiency and reliability of this method. RESULTS: We generated conditional mouse alleles using lssDNA donor templates and performed extensive characterization of the resulting mutations. We observed that the use of lssDNA molecules as donors efficiently yielded founders bearing the conditional allele, with seven out of nine projects giving rise to modified alleles. However, rearranged alleles including nucleotide changes, indels, local rearrangements and additional integrations were also frequently generated by this method. Specifically, we found that alleles containing unexpected point mutations were found in three of the nine projects analyzed. Alleles originating from illegitimate repairs or partial integration of the donor were detected in eight projects. Furthermore, additional integrations of donor molecules were identified in four out of the seven projects analyzed by copy counting. This highlighted the requirement for a thorough allele validation by polymerase chain reaction, sequencing and copy counting of the mice generated through this method. We also demonstrated the feasibility of using lssDNA donors to generate thus far problematic point mutations distant from active CRISPR cutting sites by targeting two distinct genes (Gckr and Rims1). We propose a strategy to perform extensive quality control and validation of both types of mouse models generated using lssDNA donors. CONCLUSION: lssDNA donors reproducibly generate conditional alleles and can be used to introduce point mutations away from CRISPR/Cas9 cutting sites in mice. However, our work demonstrates that thorough quality control of new models is essential prior to reliably experimenting with mice generated by this method. These advances in genome editing techniques shift the challenge of mutagenesis from generation to the validation of new mutant models.


Assuntos
DNA de Cadeia Simples , Edição de Genes/métodos , Marcação de Genes , Camundongos/genética , Alelos , Animais , Sistemas CRISPR-Cas , Mutação , Reprodutibilidade dos Testes
17.
Nat Genet ; 50(4): 572-580, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29632379

RESUMO

Individual risk of type 2 diabetes (T2D) is modified by perturbations to the mass, distribution and function of adipose tissue. To investigate the mechanisms underlying these associations, we explored the molecular, cellular and whole-body effects of T2D-associated alleles near KLF14. We show that KLF14 diabetes-risk alleles act in adipose tissue to reduce KLF14 expression and modulate, in trans, the expression of 385 genes. We demonstrate, in human cellular studies, that reduced KLF14 expression increases pre-adipocyte proliferation but disrupts lipogenesis, and in mice, that adipose tissue-specific deletion of Klf14 partially recapitulates the human phenotype of insulin resistance, dyslipidemia and T2D. We show that carriers of the KLF14 T2D risk allele shift body fat from gynoid stores to abdominal stores and display a marked increase in adipocyte cell size, and that these effects on fat distribution, and the T2D association, are female specific. The metabolic risk associated with variation at this imprinted locus depends on the sex both of the subject and of the parent from whom the risk allele derives.


Assuntos
Adipócitos/patologia , Composição Corporal/genética , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patologia , Fatores de Transcrição Sp/genética , Alelos , Animais , Distribuição da Gordura Corporal , Tamanho Celular , Elementos Facilitadores Genéticos , Feminino , Expressão Gênica , Estudo de Associação Genômica Ampla , Impressão Genômica , Humanos , Fatores de Transcrição Kruppel-Like/deficiência , Fatores de Transcrição Kruppel-Like/genética , Lipogênese/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Fatores de Risco , Caracteres Sexuais
18.
Hum Mol Genet ; 27(10): 1723-1731, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29509900

RESUMO

Polyglutamine expansions in the huntingtin gene cause Huntington's disease (HD). Huntingtin is ubiquitously expressed, leading to pathological alterations also in peripheral organs. Variations in the length of the polyglutamine tract explain up to 70% of the age-at-onset variance, with the rest of the variance attributed to genetic and environmental modifiers. To identify novel disease modifiers, we performed an unbiased mutagenesis screen on an HD mouse model, identifying a mutation in the skeletal muscle voltage-gated sodium channel (Scn4a, termed 'draggen' mutation) as a novel disease enhancer. Double mutant mice (HD; Scn4aDgn/+) had decreased survival, weight loss and muscle atrophy. Expression patterns show that the main tissue affected is skeletal muscle. Intriguingly, muscles from HD; Scn4aDgn/+ mice showed adaptive changes similar to those found in endurance exercise, including AMPK activation, fibre type switching and upregulation of mitochondrial biogenesis. Therefore, we evaluated the effects of endurance training on HD mice. Crucially, this training regime also led to detrimental effects on HD mice. Overall, these results reveal a novel role for skeletal muscle in modulating systemic HD pathogenesis, suggesting that some forms of physical exercise could be deleterious in neurodegeneration.


Assuntos
Doença de Huntington/genética , Atrofia Muscular/genética , Canal de Sódio Disparado por Voltagem NAV1.4/genética , Animais , Modelos Animais de Doenças , Treino Aeróbico , Elementos Facilitadores Genéticos , Humanos , Proteína Huntingtina/genética , Doença de Huntington/fisiopatologia , Doença de Huntington/terapia , Camundongos , Atrofia Muscular/fisiopatologia , Atrofia Muscular/terapia , Mutação , Neurônios/patologia , Neurônios/fisiologia , Biogênese de Organelas , Peptídeos/genética , Condicionamento Físico Animal , Expansão das Repetições de Trinucleotídeos/genética
19.
Mol Metab ; 6(11): 1419-1428, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29107289

RESUMO

OBJECTIVE: Genetic studies in obese rodents and humans can provide novel insights into the mechanisms involved in energy homeostasis. METHODS: In this study, we genetically mapped the chromosomal region underlying the development of severe obesity in a mouse line identified as part of a dominant N-ethyl-N-nitrosourea (ENU) mutagenesis screen. We characterized the metabolic and behavioral phenotype of obese mutant mice and examined changes in hypothalamic gene expression. In humans, we examined genetic data from people with severe early onset obesity. RESULTS: We identified an obese mouse heterozygous for a missense mutation (pR108W) in orthopedia homeobox (Otp), a homeodomain containing transcription factor required for the development of neuroendocrine cell lineages in the hypothalamus, a region of the brain important in the regulation of energy homeostasis. OtpR108W/+ mice exhibit increased food intake, weight gain, and anxiety when in novel environments or singly housed, phenotypes that may be partially explained by reduced hypothalamic expression of oxytocin and arginine vasopressin. R108W affects the highly conserved homeodomain, impairs DNA binding, and alters transcriptional activity in cells. We sequenced OTP in 2548 people with severe early-onset obesity and found a rare heterozygous loss of function variant in the homeodomain (Q153R) in a patient who also had features of attention deficit disorder. CONCLUSIONS: OTP is involved in mammalian energy homeostasis and behavior and appears to be necessary for the development of hypothalamic neural circuits. Further studies will be needed to investigate the contribution of rare variants in OTP to human energy homeostasis.


Assuntos
Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Sequência de Aminoácidos , Animais , Ansiedade/metabolismo , Sequência de Bases , Encéfalo/metabolismo , Mapeamento Cromossômico , Bases de Dados Genéticas , Feminino , Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento/genética , Genes Homeobox , Proteínas de Homeodomínio/fisiologia , Humanos , Hipotálamo/metabolismo , Masculino , Camundongos , Proteínas do Tecido Nervoso/fisiologia , Sistemas Neurossecretores/metabolismo , Obesidade/metabolismo , Fatores de Transcrição/genética , Transcriptoma/genética
20.
Nat Commun ; 8(1): 886, 2017 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-29026089

RESUMO

The developmental and physiological complexity of the auditory system is likely reflected in the underlying set of genes involved in auditory function. In humans, over 150 non-syndromic loci have been identified, and there are more than 400 human genetic syndromes with a hearing loss component. Over 100 non-syndromic hearing loss genes have been identified in mouse and human, but we remain ignorant of the full extent of the genetic landscape involved in auditory dysfunction. As part of the International Mouse Phenotyping Consortium, we undertook a hearing loss screen in a cohort of 3006 mouse knockout strains. In total, we identify 67 candidate hearing loss genes. We detect known hearing loss genes, but the vast majority, 52, of the candidate genes were novel. Our analysis reveals a large and unexplored genetic landscape involved with auditory function.The full extent of the genetic basis for hearing impairment is unknown. Here, as part of the International Mouse Phenotyping Consortium, the authors perform a hearing loss screen in 3006 mouse knockout strains and identify 52 new candidate genes for genetic hearing loss.


Assuntos
Perda Auditiva/genética , Mapas de Interação de Proteínas/genética , Animais , Conjuntos de Dados como Assunto , Testes Genéticos , Perda Auditiva/epidemiologia , Testes Auditivos , Camundongos , Camundongos Knockout , Fenótipo
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