1
|
Hazlehurst MF, Dearborn LC, Sherris AR, Loftus CT, Adgent MA, Szpiro AA, Ni Y, Day DB, Kaufman JD, Thakur N, Wright RJ, Sathyanarayana S, Carroll KN, Moore PE, Karr CJ. Long-term ozone exposure and lung function in middle childhood. ENVIRONMENTAL RESEARCH 2024; 241:117632. [PMID: 37967704 PMCID: PMC11067856 DOI: 10.1016/j.envres.2023.117632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/17/2023]
Abstract
BACKGROUND Ozone (O3) exposure interrupts normal lung development in animal models. Epidemiologic evidence further suggests impairment with higher long-term O3 exposure across early and middle childhood, although study findings to date are mixed and few have investigated vulnerable subgroups. METHODS Participants from the CANDLE study, a pregnancy cohort in Shelby County, TN, in the ECHO-PATHWAYS Consortium, were included if children were born at gestational age >32 weeks, completed a spirometry exam at age 8-9, and had a valid residential history from birth to age 8. We estimated lifetime average ambient O3 exposure based on each child's residential history from birth to age 8, using a validated fine-resolution spatiotemporal model. Spirometry was performed at the age 8-9 year study visit to assess Forced Expiratory Volume in the first second (FEV1) and Forced Vital Capacity (FVC) as primary outcomes; z-scores were calculated using sex-and-age-specific reference equations. Linear regression with robust variance estimators was used to examine associations between O3 exposure and continuous lung function z-scores, adjusted for child, sociodemographic, and home environmental factors. Potential susceptible subgroups were explored using a product term in the regression model to assess effect modification by child sex, history of bronchiolitis in infancy, and allergic sensitization. RESULTS In our sample (n = 648), O3 exposure averaged from birth to age 8 was modest (mean 26.6 [SD 1.1] ppb). No adverse associations between long-term postnatal O3 exposure were observed with either FEV1 (β = 0.12, 95% CI: -0.04, 0.29) or FVC (β = 0.03, 95% CI: -0.13, 0.19). No effect modification by child sex, history of bronchiolitis in infancy, or allergic sensitization was detected for associations with 8-year average O3. CONCLUSIONS In this sample with low O3 concentrations, we did not observe adverse associations between O3 exposures averaged from birth to age 8 and lung function in middle childhood.
Collapse
Affiliation(s)
- Marnie F Hazlehurst
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA.
| | - Logan C Dearborn
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Allison R Sherris
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Christine T Loftus
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Margaret A Adgent
- Department of Health Policy, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Adam A Szpiro
- Department of Biostatistics, School of Public Health, University of Washington, Seattle, WA, USA
| | - Yu Ni
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA; School of Public Health, College of Health and Human Services, San Diego State University, San Diego, CA, USA
| | - Drew B Day
- Center for Child Health, Behavior, and Development of Child Health, Behavior, and Development, Seattle Children's Research Institute, Seattle, WA, USA
| | - Joel D Kaufman
- Departments of Epidemiology and of Environmental and Occupational Health Sciences, School of Public Health, and Department of Medicine, School of Medicine, University of Washington, Seattle, WA, USA
| | - Neeta Thakur
- Division of Pulmonary and Critical Care Medicine, School of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Rosalind J Wright
- Departments of Pediatrics and of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sheela Sathyanarayana
- Department of Pediatrics, School of Medicine and Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, and Seattle Children's Research Institute, Seattle, WA, USA
| | - Kecia N Carroll
- Departments of Pediatrics and of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Paul E Moore
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Catherine J Karr
- Department of Pediatrics, School of Medicine and Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| |
Collapse
|
2
|
Liang S, Lu Z, Cai L, Zhu M, Zhou H, Zhang J. Multi-Omics analysis reveals molecular insights into the effects of acute ozone exposure on lung tissues of normal and obese male mice. ENVIRONMENT INTERNATIONAL 2024; 183:108436. [PMID: 38219541 DOI: 10.1016/j.envint.2024.108436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 01/16/2024]
Abstract
Certain sub-groups, including men and obese individuals, are more susceptible to ozone (O3) exposure, but the underlying molecular mechanisms remain unclear. In this study, the male mice were divided into two dietary groups: one fed a high-fat diet (HFD), mimicking obesity conditions, and the other fed a normal diet (ND), then exposed to 0.5 ppm and 2 ppm O3 for 4 h per day over two days. The HFD mice exhibited significantly higher body weight and serum lipid biochemical indicators compared to the ND mice. Obese mice also exhibited more severe pulmonary inflammation and oxidative stress. Using a multi-omics approach including proteomics, metabolomics, and lipidomics, we observed that O3 exposure induced significant pulmonary molecular changes in both obese and normal mice, primarily arachidonic acid metabolism and lipid metabolism. Different molecular biomarker responses to acute O3 exposure were also observed between two dietary groups, with immune-related proteins impacted in obese mice and PPAR pathway-related proteins affected in normal mice. Furthermore, although not statistically significant, O3 exposure tended to aggravate HFD-induced disturbances in lung glycerophospholipid metabolism. Overall, this study provides valuable molecular insights into the responses of lung to O3 exposure and highlights the potential impact of O3 on obesity-induced metabolic changes.
Collapse
Affiliation(s)
- Shijia Liang
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Zhonghua Lu
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Lijing Cai
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Miao Zhu
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Haixia Zhou
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Jie Zhang
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen, Fujian, China.
| |
Collapse
|
3
|
Sundar IK, Duraisamy SK, Choudhary I, Saini Y, Silveyra P. Acute and Repeated Ozone Exposures Differentially Affect Circadian Clock Gene Expression in Mice. Adv Biol (Weinh) 2023; 7:e2300045. [PMID: 37204107 PMCID: PMC10657336 DOI: 10.1002/adbi.202300045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/20/2023] [Indexed: 05/20/2023]
Abstract
Circadian rhythms have an established role in regulating physiological processes, such as inflammation, immunity, and metabolism. Ozone, a common environmental pollutant with strong oxidative potential, is implicated in lung inflammation/injury in asthmatics. However, whether O3 exposure affects the expression of circadian clock genes in the lungs is not known. In this study, changes in the expression of core clock genes are analyzed in the lungs of adult female and male mice exposed to filtered air (FA) or O3 using qRT-PCR. The findings are confirmed using an existing RNA-sequencing dataset from repeated FA- and O3 -exposed mouse lungs and validated by qRT-PCR. Acute O3 exposure significantly alters the expression of clock genes in the lungs of females (Per1, Cry1, and Rora) and males (Per1). RNA-seq data revealing sex-based differences in clock gene expression in the airway of males (decreased Nr1d1/Rev-erbα) and females (increased Skp1), parenchyma of females and males (decreased Nr1d1 and Fbxl3 and increased Bhlhe40 and Skp1), and alveolar macrophages of males (decreased Arntl/Bmal1, Per1, Per2, Prkab1, and Prkab2) and females (increased Cry2, Per1, Per2, Csnk1d, Csnk1e, Prkab2, and Fbxl3). These findings suggest that lung inflammation caused by O3 exposure affects clock genes which may regulate key signaling pathways.
Collapse
Affiliation(s)
- Isaac Kirubakaran Sundar
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS, USA
| | - Santhosh Kumar Duraisamy
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS, USA
| | - Ishita Choudhary
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Yogesh Saini
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Patricia Silveyra
- Department of Environmental and Occupational Health, Indiana University, School of Public Health, Bloomington, IN, USA
| |
Collapse
|
4
|
Dearborn LC, Hazlehurst MF, Loftus CT, Szpiro AA, Carroll KN, Moore PE, Adgent MA, Barrett ES, Nguyen RHN, Sathyanarayana S, LeWinn KZ, Bush NR, Kaufman JD, Karr CJ. Role of Air Pollution in the Development of Asthma Among Children with a History of Bronchiolitis in Infancy. Epidemiology 2023; 34:554-564. [PMID: 37042935 PMCID: PMC10563986 DOI: 10.1097/ede.0000000000001613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 03/12/2023] [Indexed: 04/13/2023]
Abstract
BACKGROUND Infants experiencing bronchiolitis are at increased risk for asthma, but few studies have identified modifiable risk factors. We assessed whether early life air pollution influenced child asthma and wheeze at age 4-6 years among children with a history of bronchiolitis in the first postnatal year. METHODS Children with caregiver-reported physician-diagnosed bronchiolitis were drawn from ECHO-PATHWAYS, a pooled longitudinal cohort from six US cities. We estimated their air pollution exposure from age 1 to 3 years from validated spatiotemporal models of fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ), and ozone (O 3 ). Caregivers reported children's current wheeze and asthma at age 4-6 years. We used modified Poisson regression to estimate relative risks (RR) and 95% confidence intervals (CI), adjusting for child, maternal, and home environmental factors. We assessed effect modification by child sex and maternal history of asthma with interaction models. RESULTS A total of 224 children had caregiver-reported bronchiolitis. Median (interquartile range) 2-year pollutant concentrations were 9.3 (7.8-9.9) µg/m 3 PM 2.5 , 8.5 (6.4-9.9) ppb NO 2 , and 26.6 (25.6-27.7) ppb O 3 . RRs (CI) for current wheeze per 2-ppb higher O 3 were 1.3 (1.0-1.7) and 1.4 (1.1-1.8) for asthma. NO 2 was inversely associated with wheeze and asthma whereas associations with PM 2.5 were null. We observed interactions between NO 2 and PM 2.5 and maternal history of asthma, with lower risks observed among children with a maternal history of asthma. CONCLUSION Our results are consistent with the hypothesis that exposure to modest postnatal O 3 concentrations increases the risk of asthma and wheeze among the vulnerable subpopulation of infants experiencing bronchiolitis.
Collapse
Affiliation(s)
- Logan C Dearborn
- From the Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA
| | - Marnie F Hazlehurst
- From the Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA
| | - Christine T Loftus
- From the Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA
| | - Adam A Szpiro
- Department of Biostatistics, School of Public Health, University of Washington, Seattle, WA
| | - Kecia N Carroll
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, NY
| | - Paul E Moore
- Division of Allergy, Immunology, and Pulmonology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN
| | - Margaret A Adgent
- Department of Health Policy, Vanderbilt University Medical Center, Nashville, TN
| | - Emily S Barrett
- Department of Biostatistics and Epidemiology, Environmental and Occupational Health Sciences Institute, Rutgers School of Public Health, Piscataway, NJ
- Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Ruby HN Nguyen
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN
| | - Sheela Sathyanarayana
- From the Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA
- Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA
- Seattle Children’s Research Institute, Seattle, WA
| | - Kaja Z LeWinn
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, San Francisco, San Francisco, CA
| | - Nicole R Bush
- Department of Psychiatry and Pediatrics, School of Medicine, University of California, San Francisco, San Francisco, CA
| | - Joel D Kaufman
- From the Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA
- Department of Medicine, School of Medicine, University of Washington; Seattle, WA
| | - Catherine J Karr
- From the Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA
- Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA
| |
Collapse
|
5
|
Milillo C, Falcone L, Di Carlo P, Aruffo E, Del Boccio P, Cufaro MC, Patruno A, Pesce M, Ballerini P. Ozone effect on the inflammatory and proteomic profile of human macrophages and airway epithelial cells. Respir Physiol Neurobiol 2023; 307:103979. [PMID: 36243292 DOI: 10.1016/j.resp.2022.103979] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 10/04/2022] [Accepted: 10/09/2022] [Indexed: 11/15/2022]
Abstract
Ozone (O3) is one of the most harmful urban pollutants, but its biological mechanisms have not been fully elucidated yet. Human bronchial epithelial cells (HBEpC) and human macrophage cells (differentiated human monocytic cell line) were exposed to O3 at the concentration of 240 μg/m3 (120 ppb), corresponding to the European Union alert threshold. Cell viability, reactive oxygen species (ROS) production, and pro-inflammatory cytokines release (IL-8 and TNF-α) were evaluated. Results indicated that O3 exposure increases ROS production in both cell types and enhances cytokines release in macrophages. O3 stimulated IL-8 and TNF-α in HBEpC when the cells were pretreated with Lipopolysaccharide, used to mimic a pre-existing inflammatory condition. Proteomics analysis revealed that, in HBEpC, O3 caused the up-regulation of aldo-keto reductase family 1 member B10, a recognized critical protein in lung carcinogenesis. In conclusion, our results show that 120 ppb O3 can lead to potential damage to human health suggesting the need for a revision of the actual alert levels.
Collapse
Affiliation(s)
- C Milillo
- Department of Innovative Technologies in Medicine & Dentistry, University G. d'Annunzio, 66100 Chieti, Italy; Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - L Falcone
- Department of Innovative Technologies in Medicine & Dentistry, University G. d'Annunzio, 66100 Chieti, Italy
| | - P Di Carlo
- Department of Innovative Technologies in Medicine & Dentistry, University G. d'Annunzio, 66100 Chieti, Italy; Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - E Aruffo
- Department of Innovative Technologies in Medicine & Dentistry, University G. d'Annunzio, 66100 Chieti, Italy; Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - P Del Boccio
- Department of Pharmacy, University G. d'Annunzio, 66100 Chieti, Italy; Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - M C Cufaro
- Department of Pharmacy, University G. d'Annunzio, 66100 Chieti, Italy; Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - A Patruno
- Department of Medicine and Aging Sciences, University G. d'Annunzio, 66100 Chieti, Italy
| | - M Pesce
- Department of Medicine and Aging Sciences, University G. d'Annunzio, 66100 Chieti, Italy.
| | - P Ballerini
- Department of Innovative Technologies in Medicine & Dentistry, University G. d'Annunzio, 66100 Chieti, Italy; Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| |
Collapse
|
6
|
Du X, Niu Y, Wang C, Wang W, Liu C, Meng X, Chu C, Chen R, Kan H. Ozone exposure and blood transcriptome: A randomized, controlled, crossover trial among healthy adults. ENVIRONMENT INTERNATIONAL 2022; 163:107242. [PMID: 35430440 DOI: 10.1016/j.envint.2022.107242] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/01/2022] [Accepted: 04/10/2022] [Indexed: 06/14/2023]
Abstract
RATIONALE Transcriptome-wide analysis is powerful in studying systemic RNA changes following environmental exposures. However, impacts of ozone inhalation on circulating transcriptome have not yet been examined. OBJECTIVES To explore the impact of acute ozone exposure on circulating transcriptome using RNA sequencing (RNA-seq). METHODS We recruited 32 healthy young adults in a randomized, crossover, controlled exposure trial. Each participant completed two 2-h exposure sessions of ozone (200 ppb) and clean air, respectively. Blood samples were collected at the end of each session and were used for RNA-seq. The differentially expressed genes associated with ozone exposure were assessed using Bayesian adjusted statistics from linear models in the limma R package. RESULTS A total of 29 participants finished this trial and donated their blood samples for transcriptome analysis. The average concentration of ozone was 7.8 ± 2.6 ppb under clean air and 201.1 ± 1.7 ppb under ozone exposure session. A total of 1899 genes were significantly changed (1067 up-regulated and 832 down-regulated) by ozone exposure at a false discovery rate < 0.05, in which 403 genes had a fold change of > 1.2 or < 0.8. The top 10 terms of biological processes showed that most of the differentially expressed genes were related to various functions, such as neutrophil degranulation, immune response, and neutrophil activation. Pathway enrichment analysis showed dozens of pathways were dysregulated after ozone exposure, including mitochondrial dysfunction, and glucocorticoid receptor signaling. CONCLUSION For the first time this trial characterized the genome-wide changes of mRNA in response to ozone exposure. We identified a range of differentially expressed genes that were involved in dozens of biological processes and pathways, providing novel biological insights into the systemic health effects of ozone.
Collapse
Affiliation(s)
- Xihao Du
- School of Public Health, Shanghai Institute of Infectious Disease and Biosecurity, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology Assessment, Fudan University, Shanghai 200032, China
| | - Yue Niu
- School of Public Health, Shanghai Institute of Infectious Disease and Biosecurity, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology Assessment, Fudan University, Shanghai 200032, China
| | - Cuiping Wang
- School of Public Health, Shanghai Institute of Infectious Disease and Biosecurity, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology Assessment, Fudan University, Shanghai 200032, China
| | - Weidong Wang
- School of Public Health, Shanghai Institute of Infectious Disease and Biosecurity, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology Assessment, Fudan University, Shanghai 200032, China
| | - Cong Liu
- School of Public Health, Shanghai Institute of Infectious Disease and Biosecurity, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology Assessment, Fudan University, Shanghai 200032, China
| | - Xia Meng
- School of Public Health, Shanghai Institute of Infectious Disease and Biosecurity, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology Assessment, Fudan University, Shanghai 200032, China
| | - Chen Chu
- Heart Center, Children's Hospital of Fudan University, National Center for Children's Health, Shanghai 201102, China.
| | - Renjie Chen
- School of Public Health, Shanghai Institute of Infectious Disease and Biosecurity, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology Assessment, Fudan University, Shanghai 200032, China.
| | - Haidong Kan
- School of Public Health, Shanghai Institute of Infectious Disease and Biosecurity, Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology Assessment, Fudan University, Shanghai 200032, China
| |
Collapse
|
7
|
Hathaway QA, Majumder N, Goldsmith WT, Kunovac A, Pinti MV, Harkema JR, Castranova V, Hollander JM, Hussain S. Transcriptomics of single dose and repeated carbon black and ozone inhalation co-exposure highlight progressive pulmonary mitochondrial dysfunction. Part Fibre Toxicol 2021; 18:44. [PMID: 34911549 PMCID: PMC8672524 DOI: 10.1186/s12989-021-00437-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 11/26/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Air pollution is a complex mixture of particles and gases, yet current regulations are based on single toxicant levels failing to consider potential interactive outcomes of co-exposures. We examined transcriptomic changes after inhalation co-exposure to a particulate and a gaseous component of air pollution and hypothesized that co-exposure would induce significantly greater impairments to mitochondrial bioenergetics. A whole-body inhalation exposure to ultrafine carbon black (CB), and ozone (O3) was performed, and the impact of single and multiple exposures was studied at relevant deposition levels. C57BL/6 mice were exposed to CB (10 mg/m3) and/or O3 (2 ppm) for 3 h (either a single exposure or four independent exposures). RNA was isolated from lungs and mRNA sequencing performed using the Illumina HiSeq. Lung pathology was evaluated by histology and immunohistochemistry. Electron transport chain (ETC) activities, electron flow, hydrogen peroxide production, and ATP content were assessed. RESULTS Compared to individual exposure groups, co-exposure induced significantly greater neutrophils and protein levels in broncho-alveolar lavage fluid as well as a significant increase in mRNA expression of oxidative stress and inflammation related genes. Similarly, a significant increase in hydrogen peroxide production was observed after co-exposure. After single and four exposures, co-exposure revealed a greater number of differentially expressed genes (2251 and 4072, respectively). Of these genes, 1188 (single exposure) and 2061 (four exposures) were uniquely differentially expressed, with 35 mitochondrial ETC mRNA transcripts significantly impacted after four exposures. Both O3 and co-exposure treatment significantly reduced ETC maximal activity for complexes I (- 39.3% and - 36.2%, respectively) and IV (- 55.1% and - 57.1%, respectively). Only co-exposure reduced ATP Synthase activity (- 35.7%) and total ATP content (30%). Further, the ability for ATP Synthase to function is limited by reduced electron flow (- 25%) and translation of subunits, such as ATP5F1, following co-exposure. CONCLUSIONS CB and O3 co-exposure cause unique transcriptomic changes in the lungs that are characterized by functional deficits to mitochondrial bioenergetics. Alterations to ATP Synthase function and mitochondrial electron flow underly a pathological adaptation to lung injury induced by co-exposure.
Collapse
Affiliation(s)
- Quincy A Hathaway
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism and Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
- Center for Inhalation Toxicology (iTOX), West Virginia University School of Medicine, Morgantown, WV, USA
| | - Nairrita Majumder
- Center for Inhalation Toxicology (iTOX), West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, 64 Medical Center Drive, PO Box 9229, Morgantown, WV, 26506-9229, USA
| | - William T Goldsmith
- Center for Inhalation Toxicology (iTOX), West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, 64 Medical Center Drive, PO Box 9229, Morgantown, WV, 26506-9229, USA
| | - Amina Kunovac
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism and Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
- Center for Inhalation Toxicology (iTOX), West Virginia University School of Medicine, Morgantown, WV, USA
| | - Mark V Pinti
- Mitochondria, Metabolism and Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
- West Virginia University School of Pharmacy, Morgantown, WV, USA
| | - Jack R Harkema
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Vince Castranova
- Center for Inhalation Toxicology (iTOX), West Virginia University School of Medicine, Morgantown, WV, USA
| | - John M Hollander
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism and Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
- Center for Inhalation Toxicology (iTOX), West Virginia University School of Medicine, Morgantown, WV, USA
| | - Salik Hussain
- Mitochondria, Metabolism and Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA.
- Center for Inhalation Toxicology (iTOX), West Virginia University School of Medicine, Morgantown, WV, USA.
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, 64 Medical Center Drive, PO Box 9229, Morgantown, WV, 26506-9229, USA.
| |
Collapse
|
8
|
Transcriptomics Underlying Pulmonary Ozone Pathogenesis Regulated by Inflammatory Mediators in Mice. Antioxidants (Basel) 2021; 10:antiox10091489. [PMID: 34573120 PMCID: PMC8466999 DOI: 10.3390/antiox10091489] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022] Open
Abstract
Ozone (O3) is the predominant oxidant air pollutant associated with airway inflammation, lung dysfunction, and the worsening of preexisting respiratory diseases. We previously demonstrated the injurious roles of pulmonary immune receptors, tumor necrosis factor receptor (TNFR), and toll-like receptor 4, as well as a transcription factor NF-κB, in response to O3 in mice. In the current study, we profiled time-dependent and TNFR- and NF-κB-regulated lung transcriptome changes by subacute O3 to illuminate the underlying molecular events and downstream targets. Mice lacking Tnfr1/Tnfr2 (Tnfr-/-) or Nfkb1 (Nfkb1-/-) were exposed to air or O3. Lung RNAs were prepared for cDNA microarray analyses, and downstream and upstream mechanisms were predicted by pathway analyses of the enriched genes. O3 significantly altered the genes involved in inflammation and redox (24 h), cholesterol biosynthesis and vaso-occlusion (48 h), and cell cycle and DNA repair (48–72 h). Transforming growth factor-β1 was a predicted upstream regulator. Lack of Tnfr suppressed the immune cell proliferation and lipid-related processes and heightened epithelial cell integrity, and Nfkb1 deficiency markedly suppressed lung cell cycle progress during O3 exposure. Common differentially regulated genes by TNFR and NF-κB1 (e.g., Casp8, Il6, and Edn1) were predicted to protect the lungs from cell death, connective tissue injury, and inflammation. Il6-deficient mice were susceptible to O3-induced protein hyperpermeability, indicating its defensive role, while Tnf-deficient mice were resistant to overall lung injury caused by O3. The results elucidated transcriptome dynamics and provided new insights into the molecular mechanisms regulated by TNFR and NF-κB1 in pulmonary subacute O3 pathogenesis.
Collapse
|
9
|
Choudhary I, Vo T, Paudel K, Patial S, Saini Y. Compartment-specific transcriptomics of ozone-exposed murine lungs reveals sex- and cell type-associated perturbations relevant to mucoinflammatory lung diseases. Am J Physiol Lung Cell Mol Physiol 2020; 320:L99-L125. [PMID: 33026818 DOI: 10.1152/ajplung.00381.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ozone is known to cause lung injury, and resident cells of the respiratory tract (i.e., epithelial cells and macrophages) respond to inhaled ozone in a variety of ways that affect their survival, morphology, and functioning. However, a complete understanding of the sex-associated and the cell type-specific gene expression changes in response to ozone exposure is still limited. Through transcriptome profiling, we aimed to analyze gene expression alterations and associated enrichment of biological pathways in three distinct cell type-enriched compartments of ozone-exposed murine lungs. We subchronically exposed adult male and female mice to 0.8 ppm ozone or filtered air. RNA-Seq was performed on airway epithelium-enriched airways, parenchyma, and purified airspace macrophages. Differential gene expression and biological pathway analyses were performed and supported by cellular and immunohistochemical analyses. While a majority of differentially expressed genes (DEGs) in ozone-exposed versus air-exposed groups were common between both sexes, sex-specific DEGs were also identified in all of the three tissue compartments. As compared with ozone-exposed males, ozone-exposed females had significant alterations in gene expression in three compartments. Pathways relevant to cell division and DNA repair were enriched in the ozone-exposed airways, indicating ozone-induced airway injury and repair, which was further supported by immunohistochemical analyses. In addition to cell division and DNA repair pathways, inflammatory pathways were also enriched within the parenchyma, supporting contribution by both epithelial and immune cells. Further, immune response and cytokine-cytokine receptor interactions were enriched in macrophages, indicating ozone-induced macrophage activation. Finally, our analyses also revealed the overall upregulation of mucoinflammation- and mucous cell metaplasia-associated pathways following ozone exposure.
Collapse
Affiliation(s)
- Ishita Choudhary
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Thao Vo
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Kshitiz Paudel
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Sonika Patial
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Yogesh Saini
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| |
Collapse
|
10
|
Tovar A, Smith GJ, Thomas JM, Crouse WL, Harkema JR, Kelada SNP. Transcriptional Profiling of the Murine Airway Response to Acute Ozone Exposure. Toxicol Sci 2020; 173:114-130. [PMID: 31626304 PMCID: PMC6944221 DOI: 10.1093/toxsci/kfz219] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ambient ozone (O3) exposure has serious consequences on respiratory health, including airway inflammation and injury. Decades of research have yielded thorough descriptions of these outcomes; however, less is known about the molecular processes that drive them. The aim of this study was to further describe the cellular and molecular responses to O3 exposure in murine airways, with a particular focus on transcriptional responses in 2 critical pulmonary tissue compartments: conducting airways (CA) and airway macrophages (AM). After exposing adult, female C57BL/6J mice to filtered air, 1 or 2 ppm O3, we assessed hallmark responses including airway inflammation (cell counts and cytokine secretion) and injury (epithelial permeability), followed by gene expression profiling of CA and AM by RNA-seq. As expected, we observed concentration-dependent increases in airway inflammation and injury. Conducting airways and AM both exhibited changes in gene expression to both 1 and 2 ppm O3 that were largely compartment-specific. In CA, genes associated with epithelial barrier function, detoxification processes, and cellular proliferation were altered, while O3 affected genes involved in innate immune signaling, cytokine production, and extracellular matrix remodeling in AM. Further, CA and AM also exhibited notable differences in concentration-response expression patterns for large numbers of genes. Overall, our study has described transcriptional responses to acute O3 exposure, revealing both shared and unique gene expression patterns across multiple concentrations of O3 and in 2 important O3-responsive tissues. These profiles provide broad mechanistic insight into pulmonary O3 toxicity, and reveal a variety of targets for focused follow-up studies.
Collapse
Affiliation(s)
- Adelaide Tovar
- Department of Genetics
- Curriculum in Genetics & Molecular Biology
| | - Gregory J Smith
- Department of Genetics
- Curriculum in Toxicology & Environmental Medicine
| | | | - Wesley L Crouse
- Department of Genetics
- Curriculum in Bioinformatics & Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Jack R Harkema
- Department of Pathology & Diagnostic Investigation and Institute for Integrated Toxicology, Michigan State University, East Lansing, Michigan 48824
| | - Samir N P Kelada
- Department of Genetics
- Curriculum in Genetics & Molecular Biology
- Curriculum in Toxicology & Environmental Medicine
- Curriculum in Bioinformatics & Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| |
Collapse
|
11
|
Jilling T, Ren C, Yee A, Aggarwal S, Halloran B, Ambalavanan N, Matalon S. Exposure of neonatal mice to bromine impairs their alveolar development and lung function. Am J Physiol Lung Cell Mol Physiol 2017; 314:L137-L143. [PMID: 28912380 DOI: 10.1152/ajplung.00315.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The halogen bromine (Br2) is used extensively in industry and stored and transported in large quantities. Its accidental or malicious release into the atmosphere has resulted in significant casualties. The pathophysiology of Br2-induced lung injury has been studied in adult animals, but the consequences of Br2 exposure to the developing lung are completely unknown. We exposed neonatal mouse littermates on postnatal day 3 (P3) to either Br2 at 400 ppm for 30 min (400/30), to Br2 at 600 ppm for 30 min (600/30), or to room air, then returned them to their dams and observed until P14. Mice exposed to Br2 had decreased survival (S) and had decreased weight (W) at P14 in the 400/30 group (S = 63.5%, W = 6.67 ± 0.08) and in the 600/30 group (S = 36.1%, W = 5.13 ± 0.67) as compared with air breathing mice (S = 100%, W = 7.96 ± 0.30). Alveolar development was impaired, as evidenced by increased mean linear intercept at P14. At P14, Br2 exposed mice also exhibited a decrease of arterial partial pressure of oxygen, decreased quasi-static lung compliance, as well as increased alpha smooth muscle actin mRNA and protein and increased mRNA for IL-1β, IL-6, CXCL1, and TNFα. Global gene expression, evaluated by RNA sequencing and Ingenuity Pathway Analysis, revealed persistent abnormalities in gene expression profiles at P14 involving pathways of "formation of lung" and "pulmonary development." The data indicate that Br2 inhalation injury early in life results in severe lung developmental consequences, wherein persistent inflammation and global altered developmental gene expression are likely mechanistic contributors.
Collapse
Affiliation(s)
- Tamas Jilling
- Department of Pediatrics (Neonatology), University of Alabama at Birmingham , Birmingham, Alabama
| | - Changchun Ren
- Department of Pediatrics (Neonatology), University of Alabama at Birmingham , Birmingham, Alabama
| | - Aaron Yee
- Department of Pediatrics (Neonatology), University of Alabama at Birmingham , Birmingham, Alabama
| | - Saurabh Aggarwal
- Department of Anesthesiology and Perioperative Medicine (Molecular and Translational Biomedicine), University of Alabama at Birmingham , Birmingham, Alabama
| | - Brian Halloran
- Department of Pediatrics (Neonatology), University of Alabama at Birmingham , Birmingham, Alabama
| | - Namasivayam Ambalavanan
- Department of Pediatrics (Neonatology), University of Alabama at Birmingham , Birmingham, Alabama
| | - Sadis Matalon
- Department of Anesthesiology and Perioperative Medicine (Molecular and Translational Biomedicine), University of Alabama at Birmingham , Birmingham, Alabama
| |
Collapse
|
12
|
Ciencewicki JM, Verhein KC, Gerrish K, McCaw ZR, Li J, Bushel PR, Kleeberger SR. Effects of mannose-binding lectin on pulmonary gene expression and innate immune inflammatory response to ozone. Am J Physiol Lung Cell Mol Physiol 2016; 311:L280-91. [PMID: 27106289 DOI: 10.1152/ajplung.00205.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 04/20/2016] [Indexed: 02/07/2023] Open
Abstract
Ozone is a common, potent oxidant pollutant in industrialized nations. Ozone exposure causes airway hyperreactivity, lung hyperpermeability, inflammation, and cell damage in humans and laboratory animals, and exposure to ozone has been associated with exacerbation of asthma, altered lung function, and mortality. The mechanisms of ozone-induced lung injury and differential susceptibility are not fully understood. Ozone-induced lung inflammation is mediated, in part, by the innate immune system. We hypothesized that mannose-binding lectin (MBL), an innate immunity serum protein, contributes to the proinflammatory events caused by ozone-mediated activation of the innate immune system. Wild-type (Mbl(+/+)) and MBL-deficient (Mbl(-/-)) mice were exposed to ozone (0.3 ppm) for up to 72 h, and bronchoalveolar lavage fluid was examined for inflammatory markers. Mean numbers of eosinophils and neutrophils and levels of the neutrophil attractants C-X-C motif chemokines 2 [Cxcl2 (major intrinsic protein 2)] and 5 [Cxcl5 (limb expression, LIX)] in the bronchoalveolar lavage fluid were significantly lower in Mbl(-/-) than Mbl(+/+) mice exposed to ozone. Using genome-wide mRNA microarray analyses, we identified significant differences in transcript response profiles and networks at baseline [e.g., nuclear factor erythroid-related factor 2 (NRF2)-mediated oxidative stress response] and after exposure (e.g., humoral immune response) between Mbl(+/+) and Mbl(-/-) mice. The microarray data were further analyzed to discover several informative differential response patterns and subsequent gene sets, including the antimicrobial response and the inflammatory response. We also used the lists of gene transcripts to search the LINCS L1000CDS(2) data sets to identify agents that are predicted to perturb ozone-induced changes in gene transcripts and inflammation. These novel findings demonstrate that targeted deletion of Mbl caused differential levels of inflammation-related gene sets at baseline and after exposure to ozone and significantly reduced pulmonary inflammation, thus indicating an important innate immunomodulatory role of the gene in this model.
Collapse
Affiliation(s)
- Jonathan M Ciencewicki
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Kirsten C Verhein
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Kevin Gerrish
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina; and
| | - Zachary R McCaw
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Jianying Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Pierre R Bushel
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Steven R Kleeberger
- Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina;
| |
Collapse
|
13
|
Gabehart K, Correll KA, Loader JE, White CW, Dakhama A. The lung response to ozone is determined by age and is partially dependent on toll-Like receptor 4. Respir Res 2015; 16:117. [PMID: 26410792 PMCID: PMC4583721 DOI: 10.1186/s12931-015-0279-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 09/17/2015] [Indexed: 12/25/2022] Open
Abstract
Background Ozone pollution has adverse effects on respiratory health in children and adults. This study was carried out in the mouse model to investigate the influence of age and to define the role of toll-like receptor four (TLR4) in the lung response to ozone exposure during postnatal development. Methods Female mice (1 to 6 weeks of age) were exposed for 3 h to ozone (1 part per million) or filtered air. Analyses were carried out at six and 24 h after completion of exposure, to assess the effects on lung permeability, airway neutrophilia, expression of antioxidants and chemokines, and mucus production. The role of TLR4 was defined by examining TLR4 expression in the lung during development, and by investigating the response to ozone in tlr4-deficient mice. Results Metallothionein-1, calcitonin gene-related product, and chemokine C-X-C ligand (CXCL) five were consistent markers induced by ozone throughout development. Compared with adults, neonates expressed lower levels of pulmonary TLR4 and responded with increased mucus production, and developed an attenuated response to ozone characterized by reduced albumin leakage and neutrophil influx into the airways, and lower expression of CXCL1 and CXCL2 chemokines. Examination of the responses in tlr4-deficient mice indicated that ozone-mediated airway neutrophilia, but not albumin leakage or mucus production were dependent on TLR4. Conclusions Collectively, the data demonstrate that the response to ozone is determined by age and is partially dependent on TLR4 signaling. The reduced responsiveness of the neonatal lung to ozone may be due at least in part to insufficient pulmonary TLR4 expression. Electronic supplementary material The online version of this article (doi:10.1186/s12931-015-0279-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Kelsa Gabehart
- Department of Pediatrics, National Jewish Health, 1400 Jackson Street, Denver, 80206, CO, USA
| | - Kelly A Correll
- Department of Pediatrics, National Jewish Health, 1400 Jackson Street, Denver, 80206, CO, USA
| | - Joan E Loader
- Department of Pediatrics, National Jewish Health, 1400 Jackson Street, Denver, 80206, CO, USA.,Current address: University of Colorado Denver, Children's Hospital, Aurora, CO, USA
| | - Carl W White
- Department of Pediatrics, National Jewish Health, 1400 Jackson Street, Denver, 80206, CO, USA.,Current address: University of Colorado Denver, Children's Hospital, Aurora, CO, USA
| | - Azzeddine Dakhama
- Department of Pediatrics, National Jewish Health, 1400 Jackson Street, Denver, 80206, CO, USA.
| |
Collapse
|
14
|
Inflammatory and repair pathways induced in human bronchoalveolar lavage cells with ozone inhalation. PLoS One 2015; 10:e0127283. [PMID: 26035830 PMCID: PMC4452717 DOI: 10.1371/journal.pone.0127283] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 04/14/2015] [Indexed: 02/07/2023] Open
Abstract
Background Inhalation of ambient levels of ozone causes airway inflammation and epithelial injury. Methods To examine the responses of airway cells to ozone-induced oxidative injury, 19 subjects (7 with asthma) were exposed to clean air (0ppb), medium (100ppb), and high (200ppb) ambient levels of ozone for 4h on three separate occasions in a climate-controlled chamber followed by bronchoscopy with bronchoalveolar lavage (BAL) 24h later. BAL cell mRNA expression was examined using Affymetrix GeneChip Microarray. The role of a differentially expressed gene (DEG) in epithelial injury was evaluated in an in vitro model of injury [16HBE14o- cell line scratch assay]. Results Ozone exposure caused a dose-dependent up-regulation of several biologic pathways involved in inflammation and repair including chemokine and cytokine secretion, activity, and receptor binding; metalloproteinase and endopeptidase activity; adhesion, locomotion, and migration; and cell growth and tumorigenesis regulation. Asthmatic subjects had 1.7- to 3.8-fold higher expression of many DEGs suggestive of increased proinflammatory and matrix degradation and remodeling signals. The most highly up-regulated gene was osteopontin, the protein level of which in BAL fluid increased in a dose-dependent manner after ozone exposure. Asthmatic subjects had a disproportionate increase in non-polymerized osteopontin with increasing exposure to ozone. Treatment with polymeric, but not monomeric, osteopontin enhanced the migration of epithelial cells and wound closure in an α9β1 integrin-dependent manner. Conclusions Expression profiling of BAL cells after ozone exposure reveals potential regulatory genes and pathways activated by oxidative stress. One DEG, osteopontin, promotes epithelial wound healing in an in vitro model of injury.
Collapse
|