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Li S, Huff RD, Rider CF, Yuen ACY, Carlsten C. Controlled human exposures to diesel exhaust or particle-depleted diesel exhaust with allergen modulates transcriptomic responses in the lung. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 945:173688. [PMID: 38851342 DOI: 10.1016/j.scitotenv.2024.173688] [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: 02/26/2024] [Revised: 05/13/2024] [Accepted: 05/30/2024] [Indexed: 06/10/2024]
Abstract
The evidence associating traffic-related air pollution (TRAP) with allergic asthma is growing, but the underlying mechanisms for this association remain unclear. The airway epithelium is the primary tissue exposed to TRAP, hence understanding its interactions with TRAP and allergen is important. Diesel exhaust (DE), a paradigm of TRAP, consists of particulate matter (PM) and gases. Modern diesel engines often have catalytic diesel particulate filters to reduce PM output, but these may increase gaseous concentrations, and their benefits on human health cannot be assumed. We conducted a randomized, double-blinded, crossover study using our unique in vivo human exposure system to investigate the effects of DE and allergen co-exposure, with or without particle depletion as a proxy for catalytic diesel particulate filters, on the airway epithelial transcriptome. Participants were exposed for 2 h before an allergen inhalation challenge, with each receiving filtered air and saline (FA-S), filtered air and allergen (FA-A), DE and allergen (DE-A), or particle-depleted DE and allergen (PDDE-A), over four different occasions, each separated by a 4-week washout period. Endobronchial brushings were collected 48 h after each exposure, and total RNA was sequenced. Differentially expressed genes (DEGs) were identified using DESeq2, followed by GO enrichment and pathway analysis. FA-A, DE-A, and PDDE-A exposures significantly modulated genes relative to FA-S, with 462 unique DEGs identified. FA-A uniquely modulated the highest number (↑178, ↓155), followed by DE-A (↑44, ↓23), and then PDDE-A exposure (↑15, ↓2); 6 DEGs (↑4, ↓2) were modulated by all three conditions. Exposure to PDDE-A resulted in modulation of 285 DEGs compared to DE-A exposure, further revealing 26 biological process GO terms, including "cellular response to chemokine" and "inflammatory response". The transcriptional epithelial response to diesel exhaust and allergen co-exposure is enriched in inflammatory mediators, the pattern of which is altered upon particle depletion.
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Affiliation(s)
- Shijia Li
- Air Pollution Exposure Laboratory (APEL), Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Ryan D Huff
- Air Pollution Exposure Laboratory (APEL), Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Christopher F Rider
- Air Pollution Exposure Laboratory (APEL), Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Agnes C Y Yuen
- Air Pollution Exposure Laboratory (APEL), Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Chris Carlsten
- Air Pollution Exposure Laboratory (APEL), Faculty of Medicine, University of British Columbia, Vancouver, Canada.
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Kunovac A, Hathaway QA, Thapa D, Durr AJ, Taylor AD, Rizwan S, Sharif D, Valentine SJ, Hollander JM. N 6-methyladenosine (M 6A) in fetal offspring modifies mitochondrial gene expression following gestational nano-TiO 2 inhalation exposure. Nanotoxicology 2023; 17:651-668. [PMID: 38180356 PMCID: PMC10988778 DOI: 10.1080/17435390.2023.2293144] [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: 07/26/2023] [Accepted: 12/06/2023] [Indexed: 01/06/2024]
Abstract
N6-methyladenosine (m6A) is the most prominent epitranscriptomic modification to RNA in eukaryotes, but it's role in adaptive changes within the gestational environment are poorly understood. We propose that gestational exposure to nano titanium dioxide (TiO2) contributes to cardiac m6A methylation in fetal offspring and influences mitochondrial gene expression. 10-week-old pregnant female FVB/NJ wild-type mice underwent 6 nonconsecutive days of whole-body inhalation exposure beginning on gestational day (GD) 5. Mice were exposed to filtered room air or nano-TiO2 with a target aerosol mass concentration of 12 mg/m3. At GD 15 mice were humanely killed and cardiac RNA and mitochondrial proteins extracted. Immunoprecipitation with m6A antibodies was performed followed by sequencing of immunoprecipitant (m6A) and input (mRNA) on the Illumina NextSeq 2000. Protein extraction, preparation, and LC-MS/MS were used for mitochondrial protein quantification. There were no differences in maternal or fetal pup weights, number of pups, or pup heart weights between exposure and control groups. Transcriptomic sequencing revealed 3648 differentially expressed mRNA in nano-TiO2 exposed mice (Padj ≤ 0.05). Transcripts involved in mitochondrial bioenergetics were significantly downregulated (83 of 85 genes). 921 transcripts revealed significant m6A methylation sites (Padj ≤ 0.10). 311 of the 921 mRNA were identified to have both 1) significantly altered expression and 2) differentially methylated sites. Mitochondrial proteomics revealed decreased expression of ATP Synthase subunits in the exposed group (P ≤ 0.05). The lack of m6A modifications to mitochondrial transcripts suggests a mechanism for decreased transcript stability and reduced protein expression due to gestational nano-TiO2 inhalation exposure.
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Affiliation(s)
- Amina Kunovac
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism & 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
| | - Quincy A. Hathaway
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Medical Education, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Dharendra Thapa
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism & Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Andrya J. Durr
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism & Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Andrew D. Taylor
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism & Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Saira Rizwan
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism & Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Daud Sharif
- Department of Chemistry, West Virginia University, Morgantown, WV, USA
| | | | - John M. Hollander
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
- Mitochondria, Metabolism & Bioenergetics Working Group, West Virginia University School of Medicine, Morgantown, WV, USA
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Xie L, Zhang X, Xie J, Xu Y, Li XJ, Lin L. Emerging Roles for DNA 6mA and RNA m6A Methylation in Mammalian Genome. Int J Mol Sci 2023; 24:13897. [PMID: 37762200 PMCID: PMC10531503 DOI: 10.3390/ijms241813897] [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: 08/10/2023] [Revised: 08/25/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Epigenetic methylation has been shown to play an important role in transcriptional regulation and disease pathogenesis. Recent advancements in detection techniques have identified DNA N6-methyldeoxyadenosine (6mA) and RNA N6-methyladenosine (m6A) as methylation modifications at the sixth position of adenine in DNA and RNA, respectively. While the distributions and functions of 6mA and m6A have been extensively studied in prokaryotes, their roles in the mammalian brain, where they are enriched, are still not fully understood. In this review, we provide a comprehensive summary of the current research progress on 6mA and m6A, as well as their associated writers, erasers, and readers at both DNA and RNA levels. Specifically, we focus on the potential roles of 6mA and m6A in the fundamental biological pathways of the mammalian genome and highlight the significant regulatory functions of 6mA in neurodegenerative diseases.
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Affiliation(s)
| | | | | | | | | | - Li Lin
- Guangdong Key Laboratory of Non-Human Primate Research, Laboratory of CNS Regeneration (Ministry of Education), Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou 510632, China; (L.X.); (X.Z.); (J.X.); (Y.X.); (X.-J.L.)
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