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Pomatto LCD, Cline M, Woodward N, Pakbin P, Sioutas C, Morgan TE, Finch CE, Forman HJ, Davies KJA. Aging attenuates redox adaptive homeostasis and proteostasis in female mice exposed to traffic-derived nanoparticles ('vehicular smog'). Free Radic Biol Med 2018; 121:86-97. [PMID: 29709705 PMCID: PMC5987225 DOI: 10.1016/j.freeradbiomed.2018.04.574] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 01/02/2023]
Abstract
Environmental toxicants are catalysts for protein damage, aggregation, and the aging process. Fortunately, evolution selected adaptive homeostasis as a system to mitigate such damage by expanding the normal capacity to cope with toxic stresses. Little is known about the subcellular degradative responses to proteins oxidatively damaged by air pollution. To better understand the impact of environmental toxicants upon the adaptive homeostatic response, female C57BL/6 mice were exposed for 10 weeks to filtered air or reaerosolized vehicular-derived nano-scale particulate matter (nPM), at which point tissues from young (6 month) and middle-aged (21 month) mice were studied. We found significant increases of proteolytic capacity in lung, liver, and heart. Up to two-fold increases were seen in the 20S Proteasome, the Immunoproteasome, the mitochondrial Lon protease, and NF-E2-related factor 2 (Nrf2), a major transcriptional factor for these and other stress-responsive genes. The responses were equivalent in all organs, despite the indirect input of inhaled particles to heart and liver which are downstream of lung. To our knowledge, this is the first exploration of proteostatic responses to oxidative damage by air pollution. Although, middle-aged mice had higher basal levels, their Nrf2-responsive-genes exhibited no response to nanoparticulate exposure. We also found a parallel age-associated rise in the Nrf2 transcriptional inhibitors, Bach1 and c-Myc which appear to attenuate adaptive responses in older mammals, possibly explaining the 'age-ceiling effect.' This report extends prior findings in male mice by demonstrating the involvement of proteolytic responses to traffic-related air pollution in lung, liver, and heart of female mice, with an age-dependent loss of adaptive homeostasis.
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Affiliation(s)
- Laura C D Pomatto
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Mayme Cline
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Nicholas Woodward
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Payam Pakbin
- Department of Civil and Environmental Engineering of the Viterbi School of Engineering, the University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Constantinos Sioutas
- Department of Civil and Environmental Engineering of the Viterbi School of Engineering, the University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Todd E Morgan
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Caleb E Finch
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 90089-0191, USA; Molecular and Computational Biology Program, Department of Biological Sciences of the Dornsife College of Letters, Arts & Sciences, the University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Henry Jay Forman
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 90089-0191, USA
| | - Kelvin J A Davies
- Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center, the University of Southern California, Los Angeles, CA 90089-0191, USA; Molecular and Computational Biology Program, Department of Biological Sciences of the Dornsife College of Letters, Arts & Sciences, the University of Southern California, Los Angeles, CA 90089-0191, USA; Department of Biochemistry & Molecular Medicine, Keck School of Medicine of USC, the University of Southern California, Los Angeles, CA 90089-0191, USA.
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