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Thin Air Resulting in High Pressure: Mountain Sickness and Hypoxia-Induced Pulmonary Hypertension. Can Respir J 2017; 2017:8381653. [PMID: 28522921 PMCID: PMC5385916 DOI: 10.1155/2017/8381653] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/15/2017] [Accepted: 02/28/2017] [Indexed: 12/31/2022] Open
Abstract
With rising altitude the partial pressure of oxygen falls. This phenomenon leads to hypobaric hypoxia at high altitude. Since more than 140 million people permanently live at heights above 2500 m and more than 35 million travel to these heights each year, understanding the mechanisms resulting in acute or chronic maladaptation of the human body to these circumstances is crucial. This review summarizes current knowledge of the body's acute response to these circumstances, possible complications and their treatment, and health care issues resulting from long-term exposure to high altitude. It furthermore describes the characteristic mechanisms of adaptation to life in hypobaric hypoxia expressed by the three major ethnic groups permanently dwelling at high altitude. We additionally summarize current knowledge regarding possible treatment options for hypoxia-induced pulmonary hypertension by reviewing in vitro, rodent, and human studies in this area of research.
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Pan M, Han Y, Si R, Guo R, Desai A, Makino A. Hypoxia-induced pulmonary hypertension in type 2 diabetic mice. Pulm Circ 2017; 7:175-185. [PMID: 28680577 PMCID: PMC5448524 DOI: 10.1086/690206] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 11/16/2016] [Indexed: 12/20/2022] Open
Abstract
Hypoxia-induced pulmonary hypertension (HPH) is a progressive disease that is mainly caused by chronic exposure to high altitude, chronic obstructive lung disease, and obstructive sleep apnea. The increased pulmonary vascular resistance and increased pulmonary arterial pressure result in increased right ventricular afterload, leading to right heart failure and increased morbidity. There are several clinical reports suggesting a link between PH and diabetes, insulin resistance, or obesity; however, it is unclear whether HPH is associated with diabetes as a progressive complication in diabetes. The major goal of this study is to examine the effect of diabetic "preconditioning" or priming effect on the progression of HPH and define the molecular mechanisms that explain the link between diabetes and HPH. Our data show that HPH is significantly enhanced in diabetic mice, while endothelium-dependent relaxation in pulmonary arteries is significantly attenuated in chronically hypoxic diabetic mice (DH). In addition, we demonstrate that mouse pulmonary endothelial cells (MPECs) isolated from DH mice exhibit a significant increase in mitochondrial reactive oxygen species (ROS) concentration and decreased SOD2 protein expression. Finally, scavenging mitochondrial ROS by mitoTempol restores endothelium-dependent relaxation in pulmonary arteries that is attenuated in DH mice. These data suggest that excessive mitochondrial ROS production in diabetic MPECs leads to the development of severe HPH in diabetic mice exposed to hypoxia.
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Affiliation(s)
- Minglin Pan
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ying Han
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - Rui Si
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - Rui Guo
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - Ankit Desai
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - Ayako Makino
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Physiology, University of Arizona, Tucson, AZ, USA
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53
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Peng JJ, Liu B, Xu JY, Peng J, Luo XJ. NADPH oxidase: its potential role in promotion of pulmonary arterial hypertension. Naunyn Schmiedebergs Arch Pharmacol 2017; 390:331-338. [PMID: 28190244 DOI: 10.1007/s00210-017-1359-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 02/03/2017] [Indexed: 12/27/2022]
Abstract
NADPH oxidases (NOXs) are a group of enzymes for superoxide anion (O2·- ) generation through transferring electrons from NADPH to molecular oxygen, which is rapidly converted into hydrogen peroxide (H2O2). There are seven members in NOX family, including NOX1 to NOX5, dual oxidase1, and dual oxidase 2. Recent studies have demonstrated that NOX subtypes may have different functions in different types of pulmonary arterial hypertension (PAH). The NOX-derived reactive oxygen species (ROS) are key factors that are involved in promoting the processes of pulmonary vascular remodeling, such as endothelial dysfunction, proliferation of pulmonary arterial smooth muscle cells (PASMCs), and cellular trans-differentiation, which are the basic pathologic characteristics of PAH. Inhibition of NOX shows beneficial effect on prevention of PAH development. Thus, NOX might be a potential target for PAH therapy. The main purpose of this review is to summarize recent findings on the role of NOX, particularly the NOX subtypes, in promotion of PAH development and to list recent progress regarding the NOX-based intervention for PAH.
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Affiliation(s)
- Jing-Jie Peng
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410078, China
- Department of Laboratory Medicine, Xiangya School of Medicine, Central South University, Changsha, 410013, China
| | - Bin Liu
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410078, China
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Jin-Yun Xu
- Department of Laboratory Medicine, Xiangya School of Medicine, Central South University, Changsha, 410013, China
| | - Jun Peng
- Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410078, China.
- Hunan Provincial Key Laboratory of Cardiovascular Research, School of Pharmaceutical Sciences, Central South University, Changsha, 410078, China.
| | - Xiu-Ju Luo
- Department of Laboratory Medicine, Xiangya School of Medicine, Central South University, Changsha, 410013, China.
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54
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Mitochondrial-Targeted Catalase: Extended Longevity and the Roles in Various Disease Models. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 146:203-241. [PMID: 28253986 DOI: 10.1016/bs.pmbts.2016.12.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The free-radical theory of aging was proposed more than 50 years ago. As one of the most popular mechanisms explaining the aging process, it has been extensively studied in several model organisms. However, the results remain controversial. The mitochondrial version of free-radical theory of aging proposes that mitochondria are both the primary sources of reactive oxygen species (ROS) and the primary targets of ROS-induced damage. One critical ROS is hydrogen peroxide, which is naturally degraded by catalase in peroxisomes or glutathione peroxidase within mitochondria. Our laboratory developed mice-overexpressing catalase targeted to mitochondria (mCAT), peroxisomes (pCAT), or the nucleus (nCAT) in order to investigate the role of hydrogen peroxide in different subcellular compartments in aging and age-related diseases. The mCAT mice have demonstrated the largest effects on life span and healthspan extension. This chapter will discuss the mCAT phenotype and review studies using mCAT to investigate the roles of mitochondrial oxidative stresses in various disease models, including metabolic syndrome and atherosclerosis, cardiac aging, heart failure, skeletal muscle pathology, sensory defect, neurodegenerative diseases, and cancer. As ROS has been increasingly recognized as essential signaling molecules that may be beneficial in hormesis, stress response and immunity, the potential pleiotropic, or adverse effects of mCAT are also discussed. Finally, the development of small-molecule mitochondrial-targeted therapeutic approaches is reviewed.
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55
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Adesina SE, Wade BE, Bijli KM, Kang BY, Williams CR, Ma J, Go YM, Hart CM, Sutliff RL. Hypoxia inhibits expression and function of mitochondrial thioredoxin 2 to promote pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2017; 312:L599-L608. [PMID: 28130258 PMCID: PMC5451594 DOI: 10.1152/ajplung.00258.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 02/08/2023] Open
Abstract
Pulmonary hypertension (PH) is characterized by increased pulmonary vascular resistance, pulmonary vascular remodeling, and increased pulmonary vascular pressures that often result in right ventricular dysfunction, leading to right heart failure. Evidence suggests that reactive oxygen species (ROS) contribute to PH pathogenesis by altering pulmonary vascular cell proliferation and intracellular signaling pathways. However, the role of mitochondrial antioxidants and oxidant-derived stress signaling in the development of hypoxia-induced PH is largely unknown. Therefore, we examined the role of the major mitochondrial redox regulator thioredoxin 2 (Trx2). Levels of Trx2 mRNA and protein were examined in human pulmonary arterial endothelial cells (HPAECs) and smooth muscle cells (HPASMCs) exposed to hypoxia, a common stimulus for PH, for 72 h. Hypoxia decreased Trx2 mRNA and protein levels. In vitro overexpression of Trx2 reduced hypoxia-induced H2O2 production. The effects of increased Trx2 protein level were examined in transgenic mice expressing human Trx2 (TghTrx2) that were exposed to hypoxia (10% O2) for 3 wk. TghTrx2 mice exposed to hypoxia had exacerbated increases in right ventricular systolic pressures, right ventricular hypertrophy, and increased ROS in the lung tissue. Trx2 overexpression did not attenuate hypoxia-induced increases in Trx2 oxidation or Nox4 expression. Expression of a dominant negative C93S Trx2 mutant that mimics Trx2 oxidation exacerbated hypoxia-induced increases in HPASMC H2O2 levels and cell proliferation. In conclusion, Trx2 overexpression failed to attenuate hypoxia-induced HPASMC proliferation in vitro or hypoxia-induced PH in vivo. These findings indicate that strategies to enhance Trx2 expression are unlikely to exert therapeutic effects in PH pathogenesis.
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Affiliation(s)
- Sherry E Adesina
- Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia; and
| | - Brandy E Wade
- Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia; and
| | - Kaiser M Bijli
- Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia; and
| | - Bum-Yong Kang
- Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia; and
| | | | | | - Young-Mi Go
- Department of Medicine, Emory University, Atlanta, Georgia
| | - C Michael Hart
- Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia; and.,Department of Medicine, Emory University, Atlanta, Georgia
| | - Roy L Sutliff
- Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia; and .,Department of Medicine, Emory University, Atlanta, Georgia
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56
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Ward JPT. Physiological redox signalling and regulation of ion channels: implications for pulmonary hypertension. Exp Physiol 2017; 102:1078-1082. [PMID: 28004868 DOI: 10.1113/ep086040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/13/2016] [Indexed: 12/13/2022]
Abstract
NEW FINDINGS What is the topic of this review? The review concerns the role of reactive oxygen species as physiological second messengers in potentiating G-protein-coupled receptor-mediated vasoconstriction and its potential dysregulation by oxidant stress in pulmonary hypertension. What advances does it highlight? The review highlights the concept that physiological signalling by reactive oxygen species must normally be highly compartmentalized to prevent self-regenerating oxidant stress and promiscuous and uncontrolled signalling, which contribute to the aetiology. Pulmonary hypertension is associated with oxidant stress and increased generation of reactive oxygen species (ROS) by NADPH oxidases (NOX), mitochondria and other sources. There is considerable evidence that these contribute to the aetiology via promotion of pulmonary vascular remodelling, endothelial dysfunction and enhanced vasoreactivity. However, it is now recognized that ROS act as important signalling mediators and second messengers in normal physiological conditions. Many ion channels and protein kinases crucial to pulmonary vascular function are directly or indirectly affected by redox/ROS, including K+ , Ca2+ and non-selective cation channels and Rho kinase. However, the inherent difficulties in quantifying ROS, particularly in subcellular compartments, make it uncertain whether these reported effects are of relevance in physiological rather than pathological conditions. In an attempt to address such issues, we have focused on the role of physiologically generated ROS in the regulation of G-protein-coupled receptor (GPCR)-activated vasoconstrictor pathways. We have recently reported a novel mechanism whereby low concentrations of GPCR-linked vasoconstrictors greatly potentiate Ca2+ entry via a NOX1- and ROS-mediated pathway parallel to the classical vasoconstrictor pathways of Ca2+ mobilization and activation of Rho kinase. Our findings imply that ROS signalling is highly compartmentalized in physiological conditions, but that this may be compromised by pathological increases in oxidant production, for example in pulmonary hypertension, leading to promiscuous actions that contribute to the aetiology. This model is consistent with the proposal that targeted antioxidants could prove to be an effective therapy for pulmonary hypertension.
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Affiliation(s)
- Jeremy P T Ward
- Division of Asthma, Allergy and Lung Biology, King's College London, London, UK
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57
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Sweetwyne MT, Pippin JW, Eng DG, Hudkins KL, Chiao YA, Campbell MD, Marcinek DJ, Alpers CE, Szeto HH, Rabinovitch PS, Shankland SJ. The mitochondrial-targeted peptide, SS-31, improves glomerular architecture in mice of advanced age. Kidney Int 2017; 91:1126-1145. [PMID: 28063595 DOI: 10.1016/j.kint.2016.10.036] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 10/09/2016] [Accepted: 10/27/2016] [Indexed: 01/12/2023]
Abstract
Although age-associated changes in kidney glomerular architecture have been described in mice and man, the mechanisms are unknown. It is unclear if these changes can be prevented or even reversed by systemic therapies administered at advanced age. Using light microscopy and transmission electron microscopy, our results showed glomerulosclerosis with injury to mitochondria in glomerular epithelial cells in mice aged 26 months (equivalent to a 79-year-old human). To test the hypothesis that reducing mitochondrial damage in late age would result in lowered glomerulosclerosis, we administered the mitochondrial targeted peptide, SS-31, to aged mice. Baseline (24-month-old) mice were randomized to receive 8 weeks of SS-31, or saline, and killed at 26 months of age. SS-31 treatment improved age-related mitochondrial morphology and glomerulosclerosis. Assessment of glomeruli revealed that SS-31 reduced senescence (p16, senescence-associated-ß-Gal) and increased the density of parietal epithelial cells. However, SS-31 treatment reduced markers of parietal epithelial cell activation (Collagen IV, pERK1/2, and α-smooth muscle actin). SS-31 did not impact podocyte density, but it reduced markers of podocyte injury (desmin) and improved cytoskeletal integrity (synaptopodin). This was accompanied by higher glomerular endothelial cell density (CD31). Thus, despite initiating therapy in late-age mice, a short course of SS-31 has protective benefits on glomerular mitochondria, accompanied by temporal changes to the glomerular architecture. This systemic pharmacological intervention in old-aged animals limits glomerulosclerosis and senescence, reduces parietal epithelial cell activation, and improves podocyte and endothelial cell integrity.
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Affiliation(s)
| | - Jeffrey W Pippin
- Division of Nephrology, University of Washington, Seattle, WA, USA
| | - Diana G Eng
- Division of Nephrology, University of Washington, Seattle, WA, USA
| | - Kelly L Hudkins
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Ying Ann Chiao
- Department of Pathology, University of Washington, Seattle, WA, USA
| | | | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, WA, USA
| | - Charles E Alpers
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Hazel H Szeto
- Department of Pharmacology, Weill Cornell Medical College, New York, NY, USA
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58
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Sutliff RL. New insights into mechanisms regulating pulmonary adventitial fibroblast proliferation. Acta Physiol (Oxf) 2017; 219:17-19. [PMID: 27420025 DOI: 10.1111/apha.12753] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Roy L. Sutliff
- Department of Medicine; Emory University/Atlanta VAMC; Decatur GA USA
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59
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Jernigan NL, Resta TC, Gonzalez Bosc LV. Altered Redox Balance in the Development of Chronic Hypoxia-induced Pulmonary Hypertension. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 967:83-103. [PMID: 29047083 DOI: 10.1007/978-3-319-63245-2_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Normally, the pulmonary circulation is maintained in a low-pressure, low-resistance state with little resting tone. Pulmonary arteries are thin-walled and rely heavily on pulmonary arterial distension and recruitment for reducing pulmonary vascular resistance when cardiac output is elevated. Under pathophysiological conditions, however, active vasoconstriction and vascular remodeling lead to enhanced pulmonary vascular resistance and subsequent pulmonary hypertension (PH). Chronic hypoxia is a critical pathological factor associated with the development of PH resulting from airway obstruction (COPD, sleep apnea), diffusion impairment (interstitial lung disease), developmental lung abnormalities, or high altitude exposure (World Health Organization [WHO]; Group III). The rise in pulmonary vascular resistance increases right heart afterload causing right ventricular hypertrophy that can ultimately lead to right heart failure in patients with chronic lung disease. PH is typically characterized by diminished paracrine release of vasodilators, antimitogenic factors, and antithrombotic factors (e.g., nitric oxide and protacyclin) and enhanced production of vasoconstrictors and mitogenic factors (e.g., reactive oxygen species and endothelin-1) from the endothelium and lung parenchyma. In addition, phenotypic changes to pulmonary arterial smooth muscle cells (PASMC), including alterations in Ca2+ homeostasis, Ca2+ sensitivity, and activation of transcription factors are thought to play prominent roles in the development of both vasoconstrictor and arterial remodeling components of hypoxia-associated PH. These changes in PASMC function are briefly reviewed in Sect. 1 and the influence of altered reactive oxygen species homeostasis on PASMC function discussed in Sects. 2-4.
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Affiliation(s)
- Nikki L Jernigan
- Department Cell Biology and Physiology, Vascular Physiology Group, University of New Mexico Health Sciences Center, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Thomas C Resta
- Department Cell Biology and Physiology, Vascular Physiology Group, University of New Mexico Health Sciences Center, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Laura V Gonzalez Bosc
- Department Cell Biology and Physiology, Vascular Physiology Group, University of New Mexico Health Sciences Center, University of New Mexico, Albuquerque, NM, 87131, USA.
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60
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Afolayan AJ, Alexander M, Holme RL, Michalkiewicz T, Rana U, Teng RJ, Zemanovic S, Sahoo D, Pritchard KA, Konduri GG. Domain Mapping of Heat Shock Protein 70 Reveals That Glutamic Acid 446 and Arginine 447 Are Critical for Regulating Superoxide Dismutase 2 Function. J Biol Chem 2016; 292:2369-2378. [PMID: 28028182 DOI: 10.1074/jbc.m116.756122] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 12/19/2016] [Indexed: 12/15/2022] Open
Abstract
Stress-inducible heat shock protein 70 (hsp70) interacts with superoxide dismutase 2 (SOD2) in the cytosol after synthesis to transfer the enzyme to the mitochondria for subsequent activation. However, the structural basis for this interaction remains to be defined. To map the SOD2-binding site in hsp70, mutants of hsp70 were made and tested for their ability to bind SOD2. These studies showed that SOD2 binds in the amino acid 393-537 region of the chaperone. To map the hsp70-binding site in SOD2, we used a series of pulldown assays and showed that hsp70 binds to the amino-terminal domain of SOD2. To better define the binding site, we used a series of decoy peptides derived from the primary amino acid sequence in the SOD2-binding site in hsp70. This study shows that SOD2 specifically binds to hsp70 at 445GERAMT450 Small peptides containing GERAMT inhibited the transfer of SOD2 to the mitochondria and decreased SOD2 activity in vitro and in vivo To determine the amino acid residues in hsp70 that are critical for SOD2 interactions, we substituted each amino acid residue for alanine or more conservative residues, glutamine or asparagine, in the GERAMT-binding site. Substitutions of E446A/Q and R447A/Q inhibited the ability of the GERAMT peptide to bind SOD2 and preserved SOD2 function more than other substitutions. Together, these findings indicate that the GERAMT sequence is critical for hsp70-mediated regulation of SOD2 and that Glu446 and Arg447 cooperate with other amino acid residues in the GERAMT-binding site for proper chaperone-dependent regulation of SOD2 antioxidant function.
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Affiliation(s)
- Adeleye J Afolayan
- From the Department of Pediatrics, Cardiovascular Research Center, .,Children's Research Institute
| | - Maxwell Alexander
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Rebecca L Holme
- Children's Research Institute.,Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Teresa Michalkiewicz
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Ujala Rana
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Ru-Jeng Teng
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Sara Zemanovic
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Daisy Sahoo
- Children's Research Institute.,Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Kirkwood A Pritchard
- Children's Research Institute.,Department of Surgery, Division of Pediatric Surgery, and
| | - Girija G Konduri
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
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61
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Kim SJ, Cheresh P, Jablonski RP, Morales-Nebreda L, Cheng Y, Hogan E, Yeldandi A, Chi M, Piseaux R, Ridge K, Michael Hart C, Chandel N, Scott Budinger GR, Kamp DW. Mitochondrial catalase overexpressed transgenic mice are protected against lung fibrosis in part via preventing alveolar epithelial cell mitochondrial DNA damage. Free Radic Biol Med 2016; 101:482-490. [PMID: 27840320 PMCID: PMC5928521 DOI: 10.1016/j.freeradbiomed.2016.11.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/31/2016] [Accepted: 11/01/2016] [Indexed: 12/27/2022]
Abstract
RATIONALE Alveolar epithelial cell (AEC) injury and mitochondrial dysfunction are important in the development of lung fibrosis. Our group has shown that in the asbestos exposed lung, the generation of mitochondrial reactive oxygen species (ROS) in AEC mediate mitochondrial DNA (mtDNA) damage and apoptosis which are necessary for lung fibrosis. These data suggest that mitochondrial-targeted antioxidants should ameliorate asbestos-induced lung. OBJECTIVE To determine whether transgenic mice that express mitochondrial-targeted catalase (MCAT) have reduced lung fibrosis following exposure to asbestos or bleomycin and, if so, whether this occurs in association with reduced AEC mtDNA damage and apoptosis. METHODS Crocidolite asbestos (100µg/50µL), TiO2 (negative control), bleomycin (0.025 units/50µL), or PBS was instilled intratracheally in 8-10 week-old wild-type (WT - C57Bl/6J) or MCAT mice. The lungs were harvested at 21d. Lung fibrosis was quantified by collagen levels (Sircol) and lung fibrosis scores. AEC apoptosis was assessed by cleaved caspase-3 (CC-3)/Surfactant protein C (SFTPC) immunohistochemistry (IHC) and semi-quantitative analysis. AEC (primary AT2 cells from WT and MCAT mice and MLE-12 cells) mtDNA damage was assessed by a quantitative PCR-based assay, apoptosis was assessed by DNA fragmentation, and ROS production was assessed by a Mito-Sox assay. RESULTS Compared to WT, crocidolite-exposed MCAT mice exhibit reduced pulmonary fibrosis as measured by lung collagen levels and lung fibrosis score. The protective effects in MCAT mice were accompanied by reduced AEC mtDNA damage and apoptosis. Similar findings were noted following bleomycin exposure. Euk-134, a mitochondrial SOD/catalase mimetic, attenuated MLE-12 cell DNA damage and apoptosis. Finally, compared to WT, asbestos-induced MCAT AT2 cell ROS production was reduced. CONCLUSIONS Our finding that MCAT mice have reduced pulmonary fibrosis, AEC mtDNA damage and apoptosis following exposure to asbestos or bleomycin suggests an important role for AEC mitochondrial H2O2-induced mtDNA damage in promoting lung fibrosis. We reason that strategies aimed at limiting AEC mtDNA damage arising from excess mitochondrial H2O2 production may be a novel therapeutic target for mitigating pulmonary fibrosis.
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Affiliation(s)
- Seok-Jo Kim
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Paul Cheresh
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Renea P Jablonski
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Luisa Morales-Nebreda
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Yuan Cheng
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Erin Hogan
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Anjana Yeldandi
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Monica Chi
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Raul Piseaux
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Karen Ridge
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - C Michael Hart
- Atlanta VA Medical Center, Decatur, GA, United States; Department of Medicine, Emory University, Atlanta, GA, United States
| | - Navdeep Chandel
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - G R Scott Budinger
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - David W Kamp
- Department of Medicine, Division of Pulmonary & Critical Care Medicine, Jesse Brown VA Medical Center, Chicago, IL, United States; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States.
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62
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Li MS, Adesina SE, Ellis CL, Gooch JL, Hoover RS, Williams CR. NADPH oxidase-2 mediates zinc deficiency-induced oxidative stress and kidney damage. Am J Physiol Cell Physiol 2016; 312:C47-C55. [PMID: 27806940 DOI: 10.1152/ajpcell.00208.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/24/2016] [Indexed: 01/08/2023]
Abstract
Zn2+ deficiency (ZnD) is comorbid with chronic kidney disease and worsens kidney complications. Oxidative stress is implicated in the detrimental effects of ZnD. However, the sources of oxidative stress continue to be identified. Since NADPH oxidases (Nox) are the primary enzymes that contribute to renal reactive oxygen species generation, this study's objective was to determine the role of these enzymes in ZnD-induced oxidative stress. We hypothesized that ZnD promotes NADPH oxidase upregulation, resulting in oxidative stress and kidney damage. To test this hypothesis, wild-type mice were pair-fed a ZnD or Zn2+-adequate diet. To further investigate the effects of Zn2+ bioavailability on NADPH oxidase regulation, mouse tubular epithelial cells were exposed to the Zn2+ chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) or vehicle followed by Zn2+ supplementation. We found that ZnD diet-fed mice develop microalbuminuria, electrolyte imbalance, and whole kidney hypertrophy. These markers of kidney damage are accompanied by elevated Nox2 expression and H2O2 levels. In mouse tubular epithelial cells, TPEN-induced ZnD stimulates H2O2 generation. In this in vitro model of ZnD, enhanced H2O2 generation is prevented by NADPH oxidase inhibition with diphenyleneiodonium. Specifically, TPEN promotes Nox2 expression and activation, which are reversed when intracellular Zn2+ levels are restored following Zn2+ supplementation. Finally, Nox2 knockdown by siRNA prevents TPEN-induced H2O2 generation and cellular hypertrophy in vitro. Together, these findings reveal that Nox2 is a Zn2+-regulated enzyme that mediates ZnD-induced oxidative stress and kidney hypertrophy. Understanding the specific mechanisms by which ZnD contributes to kidney damage may have an important impact on the treatment of chronic kidney disease.
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Affiliation(s)
- Mirandy S Li
- School of Medicine, Emory University, Atlanta, Georgia
| | - Sherry E Adesina
- School of Medicine, Emory University, Atlanta, Georgia.,Atlanta Veterans Affairs Medical Center, Atlanta, Georgia
| | - Carla L Ellis
- School of Medicine, Emory University, Atlanta, Georgia
| | - Jennifer L Gooch
- School of Medicine, Emory University, Atlanta, Georgia.,Pharmaceutical Sciences, Philadelphia College of Osteopathic Medicine, Suwanee, Georgia; and.,Atlanta Veterans Affairs Medical Center, Atlanta, Georgia
| | - Robert S Hoover
- School of Medicine, Emory University, Atlanta, Georgia.,Atlanta Veterans Affairs Medical Center, Atlanta, Georgia
| | - Clintoria R Williams
- School of Medicine, Emory University, Atlanta, Georgia; .,Atlanta Veterans Affairs Medical Center, Atlanta, Georgia
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Veith C, Kraut S, Wilhelm J, Sommer N, Quanz K, Seeger W, Brandes RP, Weissmann N, Schröder K. NADPH oxidase 4 is not involved in hypoxia-induced pulmonary hypertension. Pulm Circ 2016; 6:397-400. [PMID: 27683617 DOI: 10.1086/687756] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- C Veith
- Universities of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Excellence Cluster Cardio-Pulmonary System (ECCPS), Giessen, Germany
| | - S Kraut
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - J Wilhelm
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - N Sommer
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - K Quanz
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - W Seeger
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - R P Brandes
- Institute for Cardiovascular Physiology, Goethe University Frankfurt, ECCPS, Frankfurt, Germany
| | - N Weissmann
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - K Schröder
- Institute for Cardiovascular Physiology, Goethe University Frankfurt, ECCPS, Frankfurt, Germany
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64
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Zhang L, Ma C, Zhang C, Ma M, Zhang F, Zhang L, Chen Y, Cao F, Li S, Zhu D. Reactive oxygen species effect PASMCs apoptosis via regulation of dynamin-related protein 1 in hypoxic pulmonary hypertension. Histochem Cell Biol 2016; 146:71-84. [DOI: 10.1007/s00418-016-1424-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2016] [Indexed: 01/27/2023]
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Abstract
Mitochondria are a distinguishing feature of eukaryotic cells. Best known for their critical function in energy production via oxidative phosphorylation (OXPHOS), mitochondria are essential for nutrient and oxygen sensing and for the regulation of critical cellular processes, including cell death and inflammation. Such diverse functional roles for organelles that were once thought to be simple may be attributed to their distinct heteroplasmic genome, exclusive maternal lineage of inheritance, and ability to generate signals to communicate with other cellular organelles. Mitochondria are now thought of as one of the cell's most sophisticated and dynamic responsive sensing systems. Specific signatures of mitochondrial dysfunction that are associated with disease pathogenesis and/or progression are becoming increasingly important. In particular, the centrality of mitochondria in the pathological processes and clinical phenotypes associated with a range of lung diseases is emerging. Understanding the molecular mechanisms regulating the mitochondrial processes of lung cells will help to better define phenotypes and clinical manifestations associated with respiratory disease and to identify potential diagnostic and therapeutic targets.
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