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Kandasamy J, Li R, Vamesu BM, Olave N, Halloran B, Jilling T, Ballinger SW, Ambalavanan N. Mitochondrial DNA Variations Modulate Alveolar Epithelial Mitochondrial Function and Oxidative Stress in Newborn Mice Exposed to Hyperoxia. bioRxiv 2023:2023.05.17.541177. [PMID: 37292719 PMCID: PMC10245974 DOI: 10.1101/2023.05.17.541177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Oxidative stress is an important contributor to bronchopulmonary dysplasia (BPD), a form of chronic lung disease that is the most common morbidity in very preterm infants. Mitochondrial functional differences due to inherited and acquired mutations influence the pathogenesis of disorders in which oxidative stress plays a critical role. We previously showed using mitochondrial-nuclear exchange (MNX) mice that mitochondrial DNA (mtDNA) variations modulate hyperoxia-induced lung injury severity in a model of BPD. In this study, we studied the effects of mtDNA variations on mitochondrial function including mitophagy in alveolar epithelial cells (AT2) from MNX mice. We also investigated oxidant and inflammatory stress as well as transcriptomic profiles in lung tissue in mice and expression of proteins such as PINK1, Parkin and SIRT3 in infants with BPD. Our results indicate that AT2 from mice with C57 mtDNA had decreased mitochondrial bioenergetic function and inner membrane potential, increased mitochondrial membrane permeability and were exposed to higher levels of oxidant stress during hyperoxia compared to AT2 from mice with C3H mtDNA. Lungs from hyperoxia-exposed mice with C57 mtDNA also had higher levels of pro-inflammatory cytokines compared to lungs from mice with C3H mtDNA. We also noted changes in KEGG pathways related to inflammation, PPAR and glutamatergic signaling, and mitophagy in mice with certain mito-nuclear combinations but not others. Mitophagy was decreased by hyperoxia in all mice strains, but to a greater degree in AT2 and neonatal mice lung fibroblasts from hyperoxia-exposed mice with C57 mtDNA compared to C3H mtDNA. Finally, mtDNA haplogroups vary with ethnicity, and Black infants with BPD had lower levels of PINK1, Parkin and SIRT3 expression in HUVEC at birth and tracheal aspirates at 28 days of life when compared to White infants with BPD. These results indicate that predisposition to neonatal lung injury may be modulated by variations in mtDNA and mito-nuclear interactions need to be investigated to discover novel pathogenic mechanisms for BPD.
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Vamesu BM, Nicola T, Li R, Hazra S, Matalon S, Kaminski N, Ambalavanan N, Kandasamy J. Thyroid hormone modulates hyperoxic neonatal lung injury and mitochondrial function. JCI Insight 2023; 8:e160697. [PMID: 36917181 PMCID: PMC10243814 DOI: 10.1172/jci.insight.160697] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 03/08/2023] [Indexed: 03/15/2023] Open
Abstract
Mitochondrial dysfunction at birth predicts bronchopulmonary dysplasia (BPD) in extremely low-birth weight (ELBW) infants. Recently, nebulized thyroid hormone (TH), given as triiodothyronine (T3), was noted to decrease pulmonary fibrosis in adult animals through improved mitochondrial function. In this study, we tested the hypothesis that TH may have similar effects on hyperoxia-induced neonatal lung injury and mitochondrial dysfunction by testing whether i.n. T3 decreases neonatal hyperoxic lung injury in newborn mice; whether T3 improves mitochondrial function in lung homogenates, neonatal murine lung fibroblasts (NMLFs), and umbilical cord-derived mesenchymal stem cells (UC-MSCs) obtained from ELBW infants; and whether neonatal hypothyroxinemia is associated with BPD in ELBW infants. We found that inhaled T3 (given i.n.) attenuated hyperoxia-induced lung injury and mitochondrial dysfunction in newborn mice. T3 also reduced bioenergetic deficits in UC-MSCs obtained from both infants with no or mild BPD and those with moderate to severe BPD. T3 also increased the content of peroxisome proliferator-activated receptor γ coactivator 1α in lung homogenates of mice exposed to hyperoxia as well as mitochondrial potential in both NMLFs and UC-MSCs. ELBW infants who died or developed moderate to severe BPD had lower total T4 (TT4) compared with survivors with no or mild BPD. In conclusion, TH signaling and function may play a critical role in neonatal lung injury, and inhaled T3 supplementation may be useful as a therapeutic strategy for BPD.
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Affiliation(s)
- Bianca M. Vamesu
- Department of Pediatrics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Pediatrics, College of Medicine, University of South Alabama, Mobile, Alabama, USA
| | - Teodora Nicola
- Department of Pediatrics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rui Li
- Department of Pediatrics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Snehashis Hazra
- Department of Pediatrics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Sadis Matalon
- Division of Molecular and Translational Biomedicine, Department of Anesthesiology and Perioperative Medicine, and Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Naftali Kaminski
- Section of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Namasivayam Ambalavanan
- Department of Pediatrics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Pathology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jegen Kandasamy
- Department of Pediatrics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Hazra S, Li R, Vamesu BM, Jilling T, Ballinger SW, Ambalavanan N, Kandasamy J. Mesenchymal stem cell bioenergetics and apoptosis are associated with risk for bronchopulmonary dysplasia in extremely low birth weight infants. Sci Rep 2022; 12:17484. [PMID: 36261501 PMCID: PMC9582007 DOI: 10.1038/s41598-022-22478-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 10/14/2022] [Indexed: 01/12/2023] Open
Abstract
Oxidant stress contributes significantly to the pathogenesis of bronchopulmonary dysplasia (BPD) in extremely low birth weight (ELBW) infants. Mitochondrial function regulates oxidant stress responses as well as pluripotency and regenerative ability of mesenchymal stem cells (MSCs) which are critical mediators of lung development. This study was conducted to test whether differences in endogenous MSC mitochondrial bioenergetics, proliferation and survival are associated with BPD risk in ELBW infants. Umbilical cord-derived MSCs of ELBW infants who later died or developed moderate/severe BPD had lower oxygen consumption and aconitase activity but higher extracellular acidification-indicative of mitochondrial dysfunction and increased oxidant stress-when compared to MSCs from infants who survived with no/mild BPD. Hyperoxia-exposed MSCs from infants who died or developed moderate/severe BPD also had lower PINK1 expression but higher TOM20 expression and numbers of mitochondria/cell, indicating that these cells had decreased mitophagy. Finally, these MSCs were also noted to proliferate at lower rates but undergo more apoptosis in cell cultures when compared to MSCs from infants who survived with no/mild BPD. These results indicate that mitochondrial bioenergetic dysfunction and mitophagy deficit induced by oxidant stress may lead to depletion of the endogenous MSC pool and subsequent disruption of lung development in ELBW infants at increased risk for BPD.
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Affiliation(s)
- Snehashis Hazra
- Department of Pediatrics, University of Alabama at Birmingham School of Medicine, 1700 6th Avenue South, Birmingham, AL, 35233, USA
| | - Rui Li
- Department of Pediatrics, University of Alabama at Birmingham School of Medicine, 1700 6th Avenue South, Birmingham, AL, 35233, USA
| | - Bianca M Vamesu
- Department of Pediatrics, University of Alabama at Birmingham School of Medicine, 1700 6th Avenue South, Birmingham, AL, 35233, USA
| | - Tamas Jilling
- Department of Pediatrics, University of Alabama at Birmingham School of Medicine, 1700 6th Avenue South, Birmingham, AL, 35233, USA
| | - Scott W Ballinger
- Department of Pathology, University of Alabama at Birmingham School of Medicine, Birmingham, USA
| | - Namasivayam Ambalavanan
- Department of Pediatrics, University of Alabama at Birmingham School of Medicine, 1700 6th Avenue South, Birmingham, AL, 35233, USA
- Department of Pathology, University of Alabama at Birmingham School of Medicine, Birmingham, USA
| | - Jegen Kandasamy
- Department of Pediatrics, University of Alabama at Birmingham School of Medicine, 1700 6th Avenue South, Birmingham, AL, 35233, USA.
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