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Final Report: Genetic Differences in Induction of Acute Lung Injury and Inflammation in Mice
EPA Grant Number: R828112C105Subproject: this is subproject number 105 , established and managed by the Center Director under grant R828112
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Health Effects Institute
Center Director: Greenbaum, Daniel S.
Title: Genetic Differences in Induction of Acute Lung Injury and Inflammation in Mice
Investigators: Leikauf, George D.
Institution: University of Cincinnati
EPA Project Officer: Katz, Stacey
Project Period: April 1, 2000 through March 31, 2005
RFA: Health Effects Institute (1996)
Research Category: Particles and Diesel Engine Exhaust , Public/Private Partnership Center
Description:
Objective:Epidemiologic studies have indicated that small, short-term increases in the concentration of particulate matter (the complex and variable mixture of particles in the atmosphere) are associated with shortterm increases in morbidity and mortality in the population. Some individuals appear to be more at risk than others. Genetic differences among individuals may be one reason for their differing responses to particulate matter, but this mechanism is currently not well understood. One likely explanation for genetically determined differences in susceptibility is that some genes are present in the population as slightly different variations or alleles of a basic gene; as a result, these genes are expressed at higher or lower levels in some individuals than others. Identifying such genetic polymorphisms in individuals with a particular disease may help to identify those who are at risk of developing the disease, or alternatively who may respond best to treatment. An initial step in understanding the role of genetic control in responses to particulate matter is to study responses in mice because multiple animals of identical genetic composition (strains) can be generated easily. Summary/Accomplishments (Outputs/Outcomes):
Dr George Leikauf and colleagues at the University of Cincinnati Medical Center hypothesized that the mouse response to high concentrations of inhaled nickel particles was under genetic control. Nickel has been shown to cause adverse effects at high concentrations in humans and in other species and is one of the important group of transition metals (which includes iron, copper, and vanadium) found in ambient air. The investigators sought to identify the genes involved in controlling the inflammatory and toxic effects of continuous exposure to nickel particles. The primary endpoint measured was an exposed mouse?s survival time, or mean survival time for a group of exposed mice, but other endpoints related to lung inflammation and injury were also measured. Leikauf and colleagues evaluated responses in different mouse strains; in first-generation offspring that resulted from crosses of different strains (F1 mice); in backcross mice?that is, F1 mice crossed with mice of one of the parental strains; and in mice expressing different levels of the human gene for transforming growth factor-a (TGF-a), a factor associated with responses to lung injury. In the latter case, the TGF-a gene had been inserted into the mouse genome as a transgene, generating a transgenic mouse.
To identify the genes involved in the response to nickel, Leikauf and colleagues performed several complementary genetic and molecular analyses. The first was quantitative trait locus (QTL) analysis on backcross mice. This approach identified regions of individual chromosomes that were more or less closely associated with the trait or genetic characteristic of interest (namely, survival to nickel exposure). The second was haplotype analysis, which evaluated the contribution of one or several of these genetic regions to survival. The third was to use the novel microarray (or gene chip) technology; with this technique, the levels of expression of thousands of lung genes could be simultaneously evaluated during exposure to toxic levels of nickel.
Leikauf and colleagues showed convincingly that genetic factors play a key role in determining the acute response of mice to nickel toxicity. Initial experiments indicated that mice could be separated into susceptible or resistant strains according to how long they survived exposure to highly toxic levels of nickel sulfate particles (at the extremes were A strain [50 hours] and B6 strain [130 hours]). The A and B6 mouse strains showed a similar pattern of survival response to 2 other toxic agents, ozone and polytetrafluoroethylene, suggesting that similar mechanisms may govern survival of exposure to all these agents. The investigators also found little correlation between some of the hallmark parameters of lung inflammation (increased protein level and percentage of neutrophils) and survival time in response to nickel exposure. This suggests that either lung inflammation per se or the inflammatory parameters evaluated in the study are not linked to survival.
Both QTL and haplotype analysis indicated that genes on 5 or 6 chromosomes, and a region on chromosome 6 in particular, were linked to survival to nickel exposure. The identified region on chromosome 6 contains genes for TGF-a, surfactant-associated protein B (SP-B), and aquaporin-1, genes that play a key protective role in lung responses to injury. Therefore, genes in this region are likely to be important in the response to nickel toxicity. Even after identifying a QTL or QTLs associated with a particular trait, however, definitively identifying the specific gene or genes responsible for the trait is a lengthy and complex task. The results of experiments in transgenic mice expressing human TGF-a also suggested the possible involvement of a mechanism involving both TGF-a and SP-B in survival: mice expressing the highest levels of the human TGF-a gene were the most resistant to nickel toxicity and showed the smallest decline in lung levels of SP-B.
Results from the microarray analysis indicated that a small fraction (about 200) of the more than 8,000 genes (examined in lung cells derived from either nickel-sensitive or nickel-resistant mice) changed their level of expression during exposure to nickel. The expression of some genes changed in both sensitive and resistant mice, whereas the expression of other genes changed only in sensitive mice or only in resistant mice. Genes whose levels of expression changed could be grouped functionally (for example, those involved in cellular metabolism and signal transduction) or temporally (those that showed steady or delayed increases or steady or delayed decreases in expression levels). Some changes in expression were detected in genes of unknown function, indicating that some of these unidentified genes may be important in the response to nickel toxicity. The investigators enhanced the credibility of the findings from the microarray analysis by showing that selected genes with changed expression level when analyzed by other methods had similar patterns of change.
Generally, though, results from the microarray analysis could not be easily compared with those from the other genetic and molecular approaches because many genes of interest in inflammatory and injury responses were not present on the gene chip used. The use of microarrays has other limitations: It does not provide information about levels of proteins so it is not clear how detected changes in gene expression correlate with protein levels in the cell. In addition, the technique cannot distinguish in which cells, of the many found in the lung, gene expression changes are occurring. At least some of the gene expression changes detected at later times during the response to nickel probably occurred in cells that migrated into the lung as a consequence of the inflammatory response, rather than in lung cells per se.
Overall, Leikauf and colleagues have shown that mice respond to high toxic levels of inhaled nickel particles by altering gene expression. They have also preliminarily identified a small number of genes involved in susceptibility in this response. Similar genes may be involved in human responses to nickel particles in high concentrations. Additional studies are required to determine whether similar genes are involved in responses to low, ambient levels of nickel and other airborne pollutants. Further characterization of the genes involved in these responses will assist in efforts to understand the mechanisms by which pollutants act, characterize similarities and differences in gene expression among individuals? responses to a stimulus, and ultimately identify individuals who may be particularly susceptible to pollutant effects.
Supplemental Keywords:Air, ambient air quality, air toxics, epidemiology, health effects, particulate matter, biochemistry, motor vehicle emissions, diesel exhaust, animal model, genetics, susceptibility. , Air, Scientific Discipline, Health, RFA, Susceptibility/Sensitive Population/Genetic Susceptibility, Toxicology, Risk Assessments, genetic susceptability, Health Risk Assessment, air toxics, Atmospheric Sciences, Biochemistry, particulate matter, Environmental Chemistry, mobile sources, automotive exhaust, exposure assessment, risk assessment, environmentally caused disease, exposure and effects, Acute health effects, ambient air quality, cardiovascular vulnerability, indoor air quality, mortality, air quality, diesel exhaust, cardiopulmonary responses, human health risk, lung inflammation, lung injury, genetic susceptibility, air pollutants, chronic health effects, human health effects, particulates, respiratory, sensitive populations, subpopulations, diesel exhaust particles, ambient particle health effects, acute lung injury, air pollution, airway disease, environmental risks, gentics, exposure, human health, human susceptibility, human exposure, morbidity, PM, pulmonary disease, animal model
Progress and Final Reports:
Original Abstract
Main Center Abstract and Reports:
R828112 Health Effects Institute
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R828112C042 Does Inhalation of Methanol Vapor Affect Human Neurobehavior?
R828112C043 Human Responses to Nitrogen Dioxide
R828112C044 The Role of Inflammation in Ozone-Induced Lung Injury
R828112C045 How Does Exercise Affect the Dose of Inhaled Air Pollutants?
R828112C046 How Do Chemicals in Diesel Engine Exhaust Damage DNA?
R828112C047 Effect of Nitrogen Dioxide on Bacterial Respiratory infection
in Mice
R828112C048 Effects of Ozone Exposure on Airway Epithelium
R828112C049 Inhalation of Aldehydes and Effects on Breathing
R828112C050 Does Ozone Cause Precancerous Changes in Cells?
R828112C051 Effects of Formaldehyde on Human Airway Epithelial Cells Exposed in a Novel Culture System
R828112C052 Carbon Monoxide and Cardiac Arrhythmias
R828112C053 Effects of Formaldehyde and Particle-Bound Formaldehyde on Lung Macrophage Functions
R828112C054 Mechanisms for Protecting Lung Epithelial Cells Against Oxidant Injury
R828112C055 Relationship of Nitropyrene-Derived DNA Adducts to Carcinogenesis
R828112C056 Particle Trap Effects on Heavy-Duty Diesel Engine Emissions
R828112C057 Carbon Monoxide and Atherosclerosis
R828112C058 Nitrogen Dioxide and Respiratory Illness in Children
R828112C059 Noninvasive Methods for Measuring Ventilation in Mobile Subjects
R828112C060 Oxidant Air Pollutants and Lung Cancer: An Animal Model
R828112C061 Detection of Carcinogen-DNA Adducts: Development of New Methods
R828112C062 Effects of Carbon Monoxide on Heart Muscle Cells
R828112C063 Development of Personal Ozone Samplers: Three Approaches
R828112C064 Development of Biomarkers to Monitor Carcinogen Exposure
R828112C065 Effects of Prolonged Ozone Inhalation on Collagen Structure and Content in Rat Lungs
R828112C065II Prolonged Ozone Exposure and the Contractile Properties of Isolated Rat Airways
R828112C065III Changes in Complex Carbohydrate Content and Structure in Rat Lungs Caused by Prolonged Ozone Inhalation
R828112C065IV Genetic Control of Connective Tissue Protein Synthesis After Prolonged Ozone Inhalation
R828112C065V Pulmonary Function Alterations in Rats After Chronic Ozone Inhalation
R828112C065VII Prolonged Ozone Exposure Leads to Functional and Structural Changes in the Rat Nose
R828112C065VIII - IX Studies of Changes in Lung Structure and Enzyme Activities
in Rats After Prolonged Exposure to Ozone
R828112C065X An Innovative Approach to Analyzing Multiple Experimental Outcomes: A Case Study of Rats Exposed to Ozone
R828112C065XI The Consequences of Prolonged Inhalation of Ozone on Rats:
An Integrative Summary of the Results of Eight Collaborative Studies
R828112C066 Interactive Effects of Nitropyrenes in Diesel Exhaust
R828112C067 Detection of Formaldehyde–DNA Adducts: Development of New Methods
R828112C068I Comparison of the Carcinogenicity of Diesel Exhaust and Carbon Black in Rat Lungs
R828112C068II An Investigation of DNA Damage in the Lungs of Rats Exposed to Diesel Exhaust
R828112C068III No Evidence For Genetic Mutations Found In Lung Tumors From Rats Exposed To Diesel Exhaust or Carbon Black
R828112C069 Noninvasive Determination of Respiratory Ozone Absorption: The Bolus-Response Method
R828112C070 The Effects of Inhaled Oxidants and Acid Aerosols on Pulmonary Function
R828112C071 Biochemical Consequences of Ozone Reacting with Membrane Fatty Acids
R828112C072 DNA Mutations in Rats Treated with a Carcinogen Present in Diesel Exhaust
R828112C073 Developmental Neurotoxicity of Inhaled Methanol in Rats
R828112C074 Methanol Distribution in Non Pregnant and Pregnant Rodents
R828112C075 Is Increased Mortality Associated with Ozone Exposure in Mexico City?
R828112C076 Effects of Fuel Modification and Emission Control Devices on Heavy-Duty Diesel Engine Emissions
R828112C077 Metabolic Studies in Monkeys Exposed to Methanol Vapors
R828112C078 Effects of Ozone on Pulmonary Function and Airway Inflammation in Normal and Potentially Sensitive Human Subjects
R828112C079 Improvement of a Respiratory Ozone Analyzer
R828112C080 Mechanism of Oxidative Stress from Low Levels of Carbon Monoxide
R828112C081 Long-Term Exposure to Ozone: Development of Methods to Estimate Past Exposures and Health Outcomes
R828112C082 Effects of Ambient Ozone on Healthy, Wheezy, and Asthmatic Children
R828112C083 Daily Changes in Oxygen Saturation and Pulse Rate Associated with Particulate Air Pollution and Barometric Pressure
R828112C084 Evaluation of The Potential Health Effects of the Atmospheric Reaction Products of Polycyclic Aromatic Hydrocarbons
R828112C085 Mechanisms of Response to Ozone Exposure: The Role of Mast Cells in Mice
R828112C086 Statistical Methods for Epidemiologic Studies of the Health Effects of Air Pollution
R828112C087 Development of New Methods to Measure Benzene Biomarkers
R828112C088 Alveolar Changes in Rat Lungs After Long-Term Exposure to Nitric Oxide
R828112C089 Effects of Prenatal Exposure to Inhaled Methanol on Nonhuman Primates and Their Infant Offspring
R828112C090 A Pilot Study of Potential Biomarkers of Ozone Exposure
R828112C091 Effects of Concentrated Ambient Particles on the Cardiac and Pulmonary Systems of Dogs
R828112C092 Cancer, Mutations, and Adducts in Rats and Mice Exposed to Butadiene and Its Metabolites
R828112C093 Effects of Concentrated Ambient Particles in Rats and Hamsters: An Exploratory Study
R828112C094I The National Morbidity, Mortality, and Air Pollution Study: Methods and Methodologic Issues
R828112C094II The National Morbidity, Mortality, and Air Pollution Study: Morbidity and Mortality from Air Pollution in the United States
R828112C095 Association of Particulate Matter Components with Daily Mortality and Morbidity in Urban Populations
R828112C096 Acute Pulmonary Effects of Ultrafine Particles in Rats and Mice
R828112C097 Identifying Subgroups of the General Population That May Be Susceptible to Short-Term Increases in Particulate Air Pollution
R828112C098 Daily Mortality and Fine and Ultrafine Particles in Erfurt, Germany
R828112C099 A Case-Crossover Analysis of Fine Particulate Matter Air Pollution and Out-of-Hospital Sudden Cardiac Arrest
R828112C100 Effects of Mexico City Air on Rat Nose
R828112C101 Penetration of Lung Lining and Clearance of Particles Containing Benzo[a]pyrene
R828112C102 Metabolism of Ether Oxygenates Added to Gasoline
R828112C103 Characterization and Mechanisms of Chromosomal Alterations Induced by Benzene in Mice and Humans
R828112C104 Acute Cardiovascular Effects in Rats from Exposure to Urban Ambient Particles
R828112C105 Genetic Differences in Induction of Acute Lung Injury and Inflammation in Mice
R828112C106 Effects on Mice of Exposure to Ozone and Ambient Particle Pollution
R828112C107 Emissions from Diesel and Gasoline Engines Measured in Highway Tunnels