RESUMO
We carried out a 200 generation Evolve and Resequence (E&R) experiment initiated from an outbred diploid recombined 18-way synthetic base population. Replicate populations were evolved at large effective population sizes (>105 individuals), exposed to several different chemical challenges over 12 weeks of evolution, and whole-genome resequenced. Weekly forced outcrossing resulted in an average between adjacent-gene per cell division recombination rate of â¼0.0008. Despite attempts to force weekly sex, roughly half of our populations evolved cheaters and appear to be evolving asexually. Focusing on seven chemical stressors and 55 total evolved populations that remained sexual we observed large fitness gains and highly repeatable patterns of genome-wide haplotype change within chemical challenges, with limited levels of repeatability across chemical treatments. Adaptation appears highly polygenic with almost the entire genome showing significant and consistent patterns of haplotype change with little evidence for long-range linkage disequilibrium in a subset of populations for which we sequenced haploid clones. That is, almost the entire genome is under selection or drafting with selected sites. At any given locus adaptation was almost always dominated by one of the 18 founder's alleles, with that allele varying spatially and between treatments, suggesting that selection acts primarily on rare variants private to a founder or haplotype blocks harboring multiple mutations.
Assuntos
Adaptação Biológica , Genética Populacional , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Haplótipos , Reprodução Assexuada , Genoma Fúngico , Herança MultifatorialRESUMO
The Global Lung Function Initiative (GLI) has recently published international reference values for diffusing capacity of the lung for carbon monoxide (D LCO). Lower limit of normal (LLN), i.e. the 5th percentile, usually defines impaired D LCO We examined if the GLI LLN for D LCO differs from the LLN in a Swedish population of healthy, never-smoking individuals and how any such differences affect identification of subjects with respiratory burden.Spirometry, D LCO, chest high-resolution computed tomography (HRCT) and questionnaires were obtained from the first 15â040 participants, aged 50-64â
years, of the Swedish CArdioPulmonary bioImage Study (SCAPIS). Both GLI reference values and the lambda-mu-sigma (LMS) method were used to define the LLN in asymptomatic never-smokers without respiratory disease (n=4903, of which 2329 were women).Both the median and LLN for D LCO from SCAPIS were above the median and LLN from the GLI (p<0.05). The prevalence of D LCO
Assuntos
Pulmão , Adulto , Feminino , Volume Expiratório Forçado , Humanos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Valores de Referência , Espirometria , Suécia/epidemiologia , Capacidade VitalRESUMO
BACKGROUND: Differences in the expression of regulatory T cells (Tregs) have been suggested to explain why some smokers develop COPD and some do not. Upregulation of Tregs in response to smoking would restrain airway inflammation and thus the development of COPD; while the absense of such upregulation would over time lead to chronic inflammation and COPD. We hypothesized that-among COPD patients-the same mechanism would affect rate of decline in lung function; specifically, that a decreased expression of Tregs would be associated with a more rapid decline in FEV1. METHODS: Bronchoscopy with BAL was performed in 52 subjects recruited from the longitudinal OLIN COPD study; 12 with COPD and a rapid decline in lung function (loss of FEV1 ≥ 60 ml/year), 10 with COPD and a non-rapid decline in lung function (loss of FEV1 ≤ 30 ml/year), 15 current and ex-smokers and 15 non-smokers with normal lung function. BAL lymphocyte subsets were determined using flow cytometry. RESULTS: The proportions of Tregs with regulatory function (FoxP3+/CD4+CD25bright) were significantly lower in COPD subjects with a rapid decline in lung function compared to those with a non-rapid decline (p = 0.019). This result was confirmed in a mixed model regression analysis in which adjustments for inhaled corticosteroid usage, smoking, sex and age were evaluated. No significant difference was found between COPD subjects and smokers or non-smokers with normal lung function. CONCLUSIONS: COPD subjects with a rapid decline in lung function had lower proportions of T cells with regulatory function in BAL fluid, suggesting that an inability to suppress the inflammatory response following smoking might lead to a more rapid decline in FEV1. Trial registration Clinicaltrials.gov identifier NCT02729220.
Assuntos
Pulmão/imunologia , Doença Pulmonar Obstrutiva Crônica/imunologia , Fumar/efeitos adversos , Linfócitos T Reguladores/imunologia , Idoso , Broncoscopia , Contagem de Linfócito CD4 , Estudos de Casos e Controles , Estudos Transversais , Progressão da Doença , Feminino , Volume Expiratório Forçado , Fatores de Transcrição Forkhead/análise , Humanos , Imunofenotipagem , Subunidade alfa de Receptor de Interleucina-2/análise , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fenótipo , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Fumar/imunologia , Fumar/fisiopatologiaRESUMO
BACKGROUND: The imbalance between proteases and anti-proteases is considered to contribute to the development of COPD. Our aim was to evaluate the protease MMP-9, the antiprotease TIMP-1 and the MMP-9/TIMP-1-ratio as biomarkers in relation to prognosis. Prognosis was assessed as lung function decline and mortality. This was done among subjects with COPD in a population-based cohort. METHODS: In 2005, clinical examinations including spirometry and peripheral blood sampling, were made in a longitudinal population-based cohort. In total, 1542 individuals participated, whereof 594 with COPD. In 2010, 1031 subjects participated in clinical examinations, and 952 subjects underwent spirometry in both 2005 and 2010. Serum MMP-9 and TIMP-1 concentrations were measured with enzyme linked immunosorbent assay (ELISA). Mortality data were collected from the Swedish national mortality register from the date of examination in 2005 until 31st December 2010. RESULTS: The correlation between biomarkers and lung function decline was similar in non-COPD and COPD, but only significant for MMP-9 and MMP-9/TIMP-1-ratio in non-COPD. Mortality was higher in COPD than non-COPD (16% vs. 10%, p = 0.008). MMP-9 concentrations and MMP-9/TIMP-1 ratios in 2005 were higher among those who died during follow up, as well as among those alive but not participating in 2010, when compared to those participating in the 2010-examination. In non-COPD, male sex, age, burden of smoking, heart disease and MMP-9/TIMP-1 ratio were associated with increased risk for death, while increased TIMP-1 was protective. Among those with COPD, age, current smoking, increased MMP-9 and MMP-9/TIMP-1 ratio were associated with an increased risk for death. CONCLUSIONS: The expected association between these biomarkers and lung function decline in COPD was not confirmed in this population-based study, probably due to a healthy survivor effect. Still, it is suggested that increased proteolytic imbalance may be of greater prognostic importance in COPD than in non-COPD.
Assuntos
Metaloproteinase 9 da Matriz/sangue , Vigilância da População , Doença Pulmonar Obstrutiva Crônica/sangue , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Relatório de Pesquisa , Inibidor Tecidual de Metaloproteinase-1/sangue , Idoso , Biomarcadores/sangue , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Proteólise , Testes de Função Respiratória/métodos , Espirometria/métodosRESUMO
BACKGROUND: Cytotoxic lymphocytes are increased in the airways of COPD patients. Whether this increase is driven primarily by the disease or by smoking is not clear, nor whether it correlates with the rate of decline in lung function. METHODS: Bronchoscopy with BAL was performed in 52 subjects recruited from the longitudinal OLIN COPD study according to pre-determined criteria; 12 with COPD and a rapid decline in lung function (loss of FEV1 ≥ 60 ml/year), 10 with COPD and a non-rapid decline in lung function (loss of FEV1 ≤ 30 ml/year), 15 current and ex-smokers and 15 non-smokers with normal lung function. BAL lymphocyte subsets were determined using flow cytometry. RESULTS: In BAL fluid, the proportions of NK, iNKT and NKT-like cells all increased with pack-years. Within the COPD group, NK cells - but not iNKT or NKT-like cells - were significantly elevated also in subjects that had quit smoking. In contrast, current smoking was associated with a marked increase in iNKT and NKT-like cells but not in NK cells. Rate of lung function decline did not significantly affect any of the results. CONCLUSIONS: In summary, increased proportions of NK cells in BAL fluid were associated with COPD; iNKT and NKT-like cells with current smoking but not with COPD. Interestingly, NK cell percentages did not normalize in COPD subjects that had quit smoking, indicating that these cells might play a role in the continued disease progression seen in COPD even after smoking cessation. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT02729220 .
Assuntos
Células Matadoras Naturais/metabolismo , Células T Matadoras Naturais/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Fumar/efeitos adversos , Fumar/metabolismo , Idoso , Estudos Transversais , Feminino , Seguimentos , Humanos , Células Matadoras Naturais/patologia , Linfócitos/metabolismo , Linfócitos/patologia , Masculino , Pessoa de Meia-Idade , Células T Matadoras Naturais/patologia , Doença Pulmonar Obstrutiva Crônica/patologia , Fumar/patologia , Abandono do Hábito de FumarRESUMO
BACKGROUND: Chronic obstructive pulmonary disease, COPD, is an increasing cause of morbidity and mortality worldwide, and an imbalance between proteases and antiproteases has been implicated to play a role in COPD pathogenesis. Matrix metalloproteinases (MMP) are important proteases that along with their inhibitors, tissue inhibitors of metalloproteinases (TIMP), affect homeostasis of elastin and collagen, of importance for the structural integrity of human airways. Small observational studies indicate that these biomarkers are involved in the pathogenesis of COPD. The aim of this study was to investigate serum levels of MMP-9 and TIMP-1 in a large Swedish population-based cohort, and their association with disease severity and important clinical symptoms of COPD such as productive cough. METHODS: Spirometry was performed and peripheral blood samples were collected in a populations-based cohort (median age 67 years) comprising subjects with COPD (n = 594) and without COPD (n = 948), in total 1542 individuals. Serum MMP-9 and TIMP-1 concentrations were measured with enzyme linked immunosorbant assay (ELISA) and related to lung function data and symptoms. RESULTS: Median serum MMP-9 values were significantly higher in COPD compared with non-COPD 535 vs. 505 ng/ml (P = 0.017), without any significant differences in serum TIMP-1-levels or MMP-9/TIMP-1-ratio. In univariate analysis, productive cough and decreasing FEV1% predicted correlated significantly with increased MMP-9 among subjects with COPD (P = 0.004 and P = 0.001 respectively), and FEV1% predicted remained significantly associated to MMP-9 in a multivariate model adjusting for age, sex, pack years and productive cough (P = 0.033). CONCLUSION: Productive cough and decreasing FEV1 were each associated with MMP-9 in COPD, and decreasing FEV1 remained significantly associated with MMP-9 also after adjustment for common confounders in this population-based COPD cohort. The increased serum MMP-9 concentrations in COPD indicate an enhanced proteolytic activity that is related to disease severity, and further longitudinal studies are important for the understanding of MMP-9 in relation to the disease process and the pathogenesis of different COPD phenotypes.
Assuntos
Metaloproteinase 9 da Matriz/sangue , Doença Pulmonar Obstrutiva Crônica/sangue , Idoso , Biomarcadores/sangue , Estudos de Casos e Controles , Distribuição de Qui-Quadrado , Tosse/etiologia , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Volume Expiratório Forçado , Humanos , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Valor Preditivo dos Testes , Doença Pulmonar Obstrutiva Crônica/complicações , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/enzimologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Fatores de Risco , Índice de Gravidade de Doença , Suécia , Inibidor Tecidual de Metaloproteinase-1/sangue , Regulação para CimaRESUMO
The ability to adapt to acute oxidative stress (e.g. H(2)O(2), peroxynitrite, menadione, and paraquat) through transient alterations in gene expression is an important component of cellular defense mechanisms. We show that such adaptation includes Nrf2-dependent increases in cellular capacity to degrade oxidized proteins that are attributable to increased expression of the 20 S proteasome and the Pa28αß (11 S) proteasome regulator. Increased cellular levels of Nrf2, translocation of Nrf2 from the cytoplasm to the nucleus, and increased binding of Nrf2 to antioxidant response elements (AREs) or electrophile response elements (EpREs) in the 5'-untranslated region of the proteasome ß5 subunit gene (demonstrated by chromatin immunoprecipitation (or ChIP) assay) are shown to be necessary requirements for increased proteasome/Pa28αß levels, and for maximal increases in proteolytic capacity and stress resistance; Nrf2 siRNA and the Nrf2 inhibitor retinoic acid both block these adaptive changes and the Nrf2 inducers DL-sulforaphane, lipoic acid, and curcumin all replicate them without oxidant exposure. The immunoproteasome is also induced during oxidative stress adaptation, contributing to overall capacity to degrade oxidized proteins and stress resistance. Two of the three immunoproteasome subunit genes, however, contain no ARE/EpRE elements, and Nrf2 inducers, inhibitors, and siRNA all have minimal effects on immunoproteasome expression during adaptation to oxidative stress. Thus, immunoproteasome appears to be (at most) minimally regulated by the Nrf2 signal transduction pathway.
Assuntos
Adaptação Fisiológica/fisiologia , Núcleo Celular/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/fisiologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Transporte Ativo do Núcleo Celular/fisiologia , Adaptação Fisiológica/efeitos dos fármacos , Animais , Anticarcinógenos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Núcleo Celular/genética , Células Cultivadas , Curcumina/farmacologia , Citoplasma/genética , Citoplasma/metabolismo , Indução Enzimática/efeitos dos fármacos , Indução Enzimática/fisiologia , Isotiocianatos , Camundongos , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/genética , Elementos de Resposta/fisiologia , Sulfóxidos , Ácido Tióctico/farmacologia , Tiocianatos/farmacologia , Tretinoína/farmacologiaRESUMO
Advanced-generation multiparent populations (MPPs) are a valuable tool for dissecting complex traits, having more power than genome-wide association studies to detect rare variants and higher resolution than F2 linkage mapping. To extend the advantages of MPPs in budding yeast, we describe the creation and characterization of two outbred MPPs derived from 18 genetically diverse founding strains. We carried out de novo assemblies of the genomes of the 18 founder strains, such that virtually all variation segregating between these strains is known, and represented those assemblies as Santa Cruz Genome Browser tracks. We discovered complex patterns of structural variation segregating among the founders, including a large deletion within the vacuolar ATPase VMA1, several different deletions within the osmosensor MSB2, a series of deletions and insertions at PRM7 and the adjacent BSC1, as well as copy number variation at the dehydrogenase ALD2 Resequenced haploid recombinant clones from the two MPPs have a median unrecombined block size of 66 kb, demonstrating that the population is highly recombined. We pool-sequenced the two MPPs to 3270× and 2226× coverage and demonstrated that we can accurately estimate local haplotype frequencies using pooled data. We further downsampled the pool-sequenced data to â¼20-40× and showed that local haplotype frequency estimates remained accurate, with median error rates 0.8 and 0.6% at 20× and 40×, respectively. Haplotypes frequencies are estimated much more accurately than SNP frequencies obtained directly from the same data. Deep sequencing of the two populations revealed that 10 or more founders are present at a detectable frequency for > 98% of the genome, validating the utility of this resource for the exploration of the role of standing variation in the architecture of complex traits.
Assuntos
Proteínas Fúngicas/genética , Genética Populacional , Genoma Fúngico , Herança Multifatorial , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Saccharomycetales/genética , Cruzamentos Genéticos , Diploide , Estudo de Associação Genômica Ampla , FenótipoRESUMO
Although chromosomal duplications are often deleterious, in some cases they enhance cells' abilities to tolerate specific genetic or environmental challenges. Identifying the genes that confer these conditionally beneficial effects to particular chromosomal duplications can improve our understanding of the genetic and molecular mechanisms that enable certain aneuploidies to persist in cell populations and contribute to disease and evolution. Here, we perform a screen for spontaneous mutations that improve the tolerance of haploid Saccharomyces cerevisiae to hydrogen peroxide. Chromosome IV duplication is the most frequent mutation, as well as the only change in chromosomal copy number seen in the screen. Using a genetic mapping strategy that involves systematically deleting segments of a duplicated chromosome, we show that the chromosome IV's duplication effect is largely due to the generation of a second copy of the stress-inducible cytoplasmic thioredoxin peroxidase TSA2 Our findings add to a growing body of literature that shows the conditionally beneficial effects of chromosomal duplication are typically mediated by a small number of genes that enhance tolerance to specific stresses when their copy numbers are increased.
Assuntos
Duplicação Cromossômica , Cromossomos Fúngicos , Regulação Fúngica da Expressão Gênica , Peroxidases/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Estresse Fisiológico/genética , Adaptação Biológica/genética , Aneuploidia , Dosagem de Genes , Expressão Gênica , Genoma Fúngico , Peróxido de Hidrogênio/farmacologia , Mutação , Estresse Oxidativo/genética , Fenótipo , Plasmídeos/genética , Saccharomyces cerevisiae/metabolismoRESUMO
Background: Chronic obstructive pulmonary disease (COPD) is a largely underdiagnosed disease including several phenotypes. In this report, the design of a study intending to evaluate the pathophysiological mechanism in COPD in relation to the specific phenotypes non-rapid and rapid decline in lung function is described together with the recruitment process of the study population derived from a population based study. Method: The OLIN COPD study includes a population-based COPD cohort and referents without COPD identified in 2002-04 (n = 1986), and thereafter followed annually since 2005. Lung function decline was estimated from baseline in 2002-2004 to 2010 (first recruitment phase) or to 2012/2013 (second recruitment phase). Individuals who met the predefined criteria for the following four groups were identified; group A) COPD grade 2-3 with rapid decline in FEV1 and group B) COPD grade 2-3 without rapid decline in FEV1 (≥60 and ≤30 ml/year, respectively), group C) ever-smokers, and group D) non-smokers with normal lung function. Groups A-C included ever-smokers with >10 pack years. The intention was to recruit 15 subjects in each of the groups A-D. Results: From the database groups A-D were identified; group A n = 37, group B n = 29, group C n = 41, and group D n = 55. Fifteen subjects were recruited from groups C and D, while this goal was not reached in the groups A (n = 12) and B (n = 10). The most common reasons for excluding individuals identified as A or B were comorbidities contraindicating bronchoscopy, or inflammatory diseases/immune suppressive medication expected to affect the outcome. Conclusion: The study is expected to generate important results regarding pathophysiological mechanisms associated with rate of decline in lung function among subjects with COPD and the in-detail described recruitment process, including reasons for non-participation, is a strength when interpreting the results in forthcoming studies.
RESUMO
Quantitative traits are often influenced by many loci with small effects. Identifying most of these loci and resolving them to specific genes or genetic variants is challenging. Yet, achieving such a detailed understanding of quantitative traits is important, as it can improve our knowledge of the genetic and molecular basis of heritable phenotypic variation. In this study, we use a genetic mapping strategy that involves recurrent backcrossing with phenotypic selection to obtain new insights into an ecologically, industrially, and medically relevant quantitative trait-tolerance of oxidative stress, as measured based on resistance to hydrogen peroxide. We examine the genetic basis of hydrogen peroxide resistance in three related yeast crosses and detect 64 distinct genomic loci that likely influence the trait. By precisely resolving or cloning a number of these loci, we demonstrate that a broad spectrum of cellular processes contribute to hydrogen peroxide resistance, including DNA repair, scavenging of reactive oxygen species, stress-induced MAPK signaling, translation, and water transport. Consistent with the complex genetic and molecular basis of hydrogen peroxide resistance, we show two examples where multiple distinct causal genetic variants underlie what appears to be a single locus. Our results improve understanding of the genetic and molecular basis of a highly complex, model quantitative trait.
Assuntos
Modelos Genéticos , Estresse Oxidativo/genética , Locos de Características Quantitativas , Mapeamento Cromossômico , Cruzamentos Genéticos , Estudos de Associação Genética , Variação Genética , Peróxido de Hidrogênio/metabolismo , Endogamia , Modelos Moleculares , Saccharomyces cerevisiae/genética , Saccharomycetales/genéticaRESUMO
Genetic heterogeneity occurs when individuals express similar phenotypes as a result of different underlying mechanisms. Although such heterogeneity is known to be a potential source of unexplained heritability in genetic mapping studies, its prevalence and molecular basis are not fully understood. Here we show that substantial genetic heterogeneity underlies a model phenotype--the ability to grow invasively--in a cross of two Saccharomyces cerevisiae strains. The heterogeneous basis of this trait across genotypes and environments makes it difficult to detect causal loci with standard genetic mapping techniques. However, using selective genotyping in the original cross, as well as in targeted backcrosses, we detected four loci that contribute to differences in the ability to grow invasively. Identification of causal genes at these loci suggests that they act by changing the underlying regulatory architecture of invasion. We verified this point by deleting many of the known transcriptional activators of invasion, as well as the gene encoding the cell surface protein Flo11 from five relevant segregants and showing that these individuals differ in the genes they require for invasion. Our work illustrates the extensive genetic heterogeneity that can underlie a trait and suggests that regulatory rewiring is a basic mechanism that gives rise to this heterogeneity.