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Hu L, Yu Y, Shen Y, Huang H, Lin D, Wang K, Yu Y, Li K, Cao Y, Wang Q, Sun X, Qiu Z, Wei D, Shen B, Chen J, Fulton D, Ji Y, Wang J, Chen F. Ythdf2 promotes pulmonary hypertension by suppressing Hmox1-dependent anti-inflammatory and antioxidant function in alveolar macrophages. Redox Biol 2023; 61:102638. [PMID: 36801705 PMCID: PMC9975317 DOI: 10.1016/j.redox.2023.102638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/04/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Pulmonary hypertension (PH) is a devastating disease characterized by irreversible pulmonary vascular remodeling (PVR) that causes right ventricular failure and death. The early alternative activation of macrophages is a critical event in the development of PVR and PH, but the underlying mechanisms remain elusive. Previously we have shown that N6-methyladenosine (m6A) modifications of RNA contribute to phenotypic switching of pulmonary artery smooth muscle cells and PH. In the current study, we identify Ythdf2, an m6A reader, as an important regulator of pulmonary inflammation and redox regulation in PH. In a mouse model of PH, the protein expression of Ythdf2 was increased in alveolar macrophages (AMs) during the early stages of hypoxia. Mice with a myeloid specific knockout of Ythdf2 (Ythdf2Lyz2 Cre) were protected from PH with attenuated right ventricular hypertrophy and PVR compared to control mice and this was accompanied by decreased macrophage polarization and oxidative stress. In the absence of Ythdf2, heme oxygenase 1 (Hmox1) mRNA and protein expression were significantly elevated in hypoxic AMs. Mechanistically, Ythdf2 promoted the degradation of Hmox1 mRNA in a m6A dependent manner. Furthermore, an inhibitor of Hmox1 promoted macrophage alternative activation, and reversed the protection from PH seen in Ythdf2Lyz2 Cre mice under hypoxic exposure. Together, our data reveal a novel mechanism linking m6A RNA modification with changes in macrophage phenotype, inflammation and oxidative stress in PH, and identify Hmox1 as a downstream target of Ythdf2, suggesting that Ythdf2 may be a therapeutic target in PH.
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Affiliation(s)
- Li Hu
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China; Gusu School, Nanjing Medical University, Suzhou, China
| | - Yanfang Yu
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China
| | - Yueyao Shen
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China
| | - Huijie Huang
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China
| | - Donghai Lin
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China
| | - Kang Wang
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China
| | - Youjia Yu
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China
| | - Kai Li
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China
| | - Yue Cao
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China
| | - Qiang Wang
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xiaoxuan Sun
- Department of Rheumatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhibing Qiu
- Department of Thoracic and Cardiovascular Surgery, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Dong Wei
- Wuxi Lung Transplantation Center, Wuxi People's Hospital Affiliated with Nanjing Medical University, Wuxi, China
| | - Bin Shen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Jingyu Chen
- Wuxi Lung Transplantation Center, Wuxi People's Hospital Affiliated with Nanjing Medical University, Wuxi, China
| | - David Fulton
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Yong Ji
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Jie Wang
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China.
| | - Feng Chen
- Department of Forensic Medicine, Nanjing Medical University, Nanjing, China; Gusu School, Nanjing Medical University, Suzhou, China; Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA, USA; Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, China.
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Christou H, Khalil RA. Mechanisms of pulmonary vascular dysfunction in pulmonary hypertension and implications for novel therapies. Am J Physiol Heart Circ Physiol 2022; 322:H702-H724. [PMID: 35213243 PMCID: PMC8977136 DOI: 10.1152/ajpheart.00021.2022] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/22/2022] [Accepted: 02/22/2022] [Indexed: 12/21/2022]
Abstract
Pulmonary hypertension (PH) is a serious disease characterized by various degrees of pulmonary vasoconstriction and progressive fibroproliferative remodeling and inflammation of the pulmonary arterioles that lead to increased pulmonary vascular resistance, right ventricular hypertrophy, and failure. Pulmonary vascular tone is regulated by a balance between vasoconstrictor and vasodilator mediators, and a shift in this balance to vasoconstriction is an important component of PH pathology, Therefore, the mainstay of current pharmacological therapies centers on pulmonary vasodilation methodologies that either enhance vasodilator mechanisms such as the NO-cGMP and prostacyclin-cAMP pathways and/or inhibit vasoconstrictor mechanisms such as the endothelin-1, cytosolic Ca2+, and Rho-kinase pathways. However, in addition to the increased vascular tone, many patients have a "fixed" component in their disease that involves altered biology of various cells in the pulmonary vascular wall, excessive pulmonary artery remodeling, and perivascular fibrosis and inflammation. Pulmonary arterial smooth muscle cell (PASMC) phenotypic switch from a contractile to a synthetic and proliferative phenotype is an important factor in pulmonary artery remodeling. Although current vasodilator therapies also have some antiproliferative effects on PASMCs, they are not universally successful in halting PH progression and increasing survival. Mild acidification and other novel approaches that aim to reverse the resident pulmonary vascular pathology and structural remodeling and restore a contractile PASMC phenotype could ameliorate vascular remodeling and enhance the responsiveness of PH to vasodilator therapies.
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Affiliation(s)
- Helen Christou
- Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Raouf A Khalil
- Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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Targeting Heme Oxygenase-1 in the Arterial Response to Injury and Disease. Antioxidants (Basel) 2020; 9:antiox9090829. [PMID: 32899732 PMCID: PMC7554957 DOI: 10.3390/antiox9090829] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 02/06/2023] Open
Abstract
Heme oxygenase-1 (HO-1) catalyzes the degradation of heme into carbon monoxide (CO), iron, and biliverdin, which is rapidly metabolized to bilirubin. The activation of vascular smooth muscle cells (SMCs) plays a critical role in mediating the aberrant arterial response to injury and a number of vascular diseases. Pharmacological induction or gene transfer of HO-1 improves arterial remodeling in animal models of post-angioplasty restenosis, vascular access failure, atherosclerosis, transplant arteriosclerosis, vein grafting, and pulmonary arterial hypertension, whereas genetic loss of HO-1 exacerbates the remodeling response. The vasoprotection evoked by HO-1 is largely ascribed to the generation of CO and/or the bile pigments, biliverdin and bilirubin, which exert potent antioxidant and anti-inflammatory effects. In addition, these molecules inhibit vascular SMC proliferation, migration, apoptosis, and phenotypic switching. Several therapeutic strategies are currently being pursued that may allow for the targeting of HO-1 in arterial remodeling in various pathologies, including the use of gene delivery approaches, the development of novel inducers of the enzyme, and the administration of unique formulations of CO and bilirubin.
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Nath KA, Grande JP, Belcher JD, Garovic VD, Croatt AJ, Hillestad ML, Barry MA, Nath MC, Regan RF, Vercellotti GM. Antithrombotic effects of heme-degrading and heme-binding proteins. Am J Physiol Heart Circ Physiol 2020; 318:H671-H681. [PMID: 32004074 DOI: 10.1152/ajpheart.00280.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In the murine venous thrombosis model induced by ligation of the inferior vena cava (IVCL), genetic deficiency of heme oxygenase-1 (HO-1) increases clot size. This study examined whether induction of HO-1 or administration of its products reduces thrombosis. Venous HO-1 upregulation by gene delivery reduced clot size, as did products of HO activity, biliverdin, and carbon monoxide. Induction of HO-1 by hemin reduced clot formation, clot size, and upregulation of plasminogen activator inhibitor-1 (PAI-1) that occurs in the IVCL model, while leaving urokinase plasminogen activator (uPA) and tissue plasminogen activator (tPA) expression unaltered. The reductive effect of hemin on clot size required HO activity. The IVCL model exhibited relatively high concentrations of heme that peaked just before maximum clot size, then declined as clot size decreased. Administration of hemin decreased heme concentration in the IVCL model. HO-2 mRNA was induced twofold in the IVCL model (vs. 40-fold HO-1 induction), but clot size was not increased in HO-2-/- mice compared with HO-2+/+ mice. Hemopexin, the major heme-binding protein, was induced in the IVCL model, and clot size was increased in hemopexin-/- mice compared with hemopexin+/+ mice. We conclude that in the IVCL model, the heme-degrading protein HO-1 and HO products inhibit thrombus formation, as does the heme-binding protein, hemopexin. The reductive effects of hemin administration require HO activity and are mediated, in part, by reducing PAI-1 upregulation in the IVCL model. We speculate that HO-1, HO, and hemopexin reduce clot size by restraining the increase in clot concentration of heme (now recognized as a procoagulant) that otherwise occurs.NEW & NOTEWORTHY This study provides conclusive evidence that two proteins, one heme-degrading and the other heme-binding, inhibit clot formation. This may serve as a new therapeutic strategy in preventing and treating venous thromboembolic disease.
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Affiliation(s)
- Karl A Nath
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Joseph P Grande
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - John D Belcher
- Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, Minnesota
| | - Vesna D Garovic
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | - Anthony J Croatt
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | | | - Michael A Barry
- Division of Infectious Diseases, Mayo Clinic, Rochester, Minnesota
| | - Meryl C Nath
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Raymond F Regan
- Department of Emergency Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Gregory M Vercellotti
- Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, Minnesota
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Egemnazarov B, Crnkovic S, Nagy BM, Olschewski H, Kwapiszewska G. Right ventricular fibrosis and dysfunction: Actual concepts and common misconceptions. Matrix Biol 2018; 68-69:507-521. [PMID: 29343458 DOI: 10.1016/j.matbio.2018.01.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 12/25/2022]
Abstract
Fibrosis and remodeling of the right ventricle (RV) are associated with RV dysfunction and mortality of patients with pulmonary hypertension (PH) but it is unknown how much RV fibrosis contributes to RV dysfunction and mortality. RV fibrosis manifests as fibroblast accumulation and collagen deposition which may be excessive. Although extracellular matrix deposition leads to elevated ventricular stiffness, it is not known to which extent it affects RV function. Various animal models of pulmonary hypertension have been established to investigate the role of fibrosis in RV dysfunction and failure. However, they do not perfectly resemble the human disease. In the current review we describe the major characteristics of RV fibrosis, molecular mechanisms regulating the fibrotic process, and discuss how therapeutic targeting of fibrosis might affect RV function.
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Affiliation(s)
| | - Slaven Crnkovic
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Bence M Nagy
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Horst Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Grazyna Kwapiszewska
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Institute of Physiology, Medical University of Graz, Graz, Austria.
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Abstract
Heme oxygenases are composed of two isozymes, Hmox1 and Hmox2, that catalyze the degradation of heme to carbon monoxide (CO), ferrous iron, and biliverdin, the latter of which is subsequently converted to bilirubin. While initially considered to be waste products, CO and biliverdin/bilirubin have been shown over the last 20 years to modulate key cellular processes, such as inflammation, cell proliferation, and apoptosis, as well as antioxidant defense. This shift in paradigm has led to the importance of heme oxygenases and their products in cell physiology now being well accepted. The identification of the two human cases thus far of heme oxygenase deficiency and the generation of mice deficient in Hmox1 or Hmox2 have reiterated a role for these enzymes in both normal cell function and disease pathogenesis, especially in the context of cardiovascular disease. This review covers the current knowledge on the function of both Hmox1 and Hmox2 at both a cellular and tissue level in the cardiovascular system. Initially, the roles of heme oxygenases in vascular health and the regulation of processes central to vascular diseases are outlined, followed by an evaluation of the role(s) of Hmox1 and Hmox2 in various diseases such as atherosclerosis, intimal hyperplasia, myocardial infarction, and angiogenesis. Finally, the therapeutic potential of heme oxygenases and their products are examined in a cardiovascular disease context, with a focus on how the knowledge we have gained on these enzymes may be capitalized in future clinical studies.
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Affiliation(s)
- Anita Ayer
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia; and Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham Veterans Administration Medical Center, Birmingham, Alabama
| | - Abolfazl Zarjou
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia; and Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham Veterans Administration Medical Center, Birmingham, Alabama
| | - Anupam Agarwal
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia; and Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham Veterans Administration Medical Center, Birmingham, Alabama
| | - Roland Stocker
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia; and Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham Veterans Administration Medical Center, Birmingham, Alabama
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Chan EC, Dusting GJ, Liu GS, Jiang F. Redox mechanisms of the beneficial effects of heme oxygenase in hypertension. J Hypertens 2014; 32:1379-86; discussion 1387. [DOI: 10.1097/hjh.0000000000000179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Duckles H, Boycott HE, Al-Owais MM, Elies J, Johnson E, Dallas ML, Porter KE, Giuntini F, Boyle JP, Scragg JL, Peers C. Heme oxygenase-1 regulates cell proliferation via carbon monoxide-mediated inhibition of T-type Ca2+ channels. Pflugers Arch 2014; 467:415-27. [PMID: 24744106 PMCID: PMC4293494 DOI: 10.1007/s00424-014-1503-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/14/2014] [Accepted: 03/14/2014] [Indexed: 11/24/2022]
Abstract
Induction of the antioxidant enzyme heme oxygenase-1 (HO-1) affords cellular protection and suppresses proliferation of vascular smooth muscle cells (VSMCs) associated with a variety of pathological cardiovascular conditions including myocardial infarction and vascular injury. However, the underlying mechanisms are not fully understood. Over-expression of Cav3.2 T-type Ca2+ channels in HEK293 cells raised basal [Ca2+]i and increased proliferation as compared with non-transfected cells. Proliferation and [Ca2+]i levels were reduced to levels seen in non-transfected cells either by induction of HO-1 or exposure of cells to the HO-1 product, carbon monoxide (CO) (applied as the CO releasing molecule, CORM-3). In the aortic VSMC line A7r5, proliferation was also inhibited by induction of HO-1 or by exposure of cells to CO, and patch-clamp recordings indicated that CO inhibited T-type (as well as L-type) Ca2+ currents in these cells. Finally, in human saphenous vein smooth muscle cells, proliferation was reduced by T-type channel inhibition or by HO-1 induction or CO exposure. The effects of T-type channel blockade and HO-1 induction were non-additive. Collectively, these data indicate that HO-1 regulates proliferation via CO-mediated inhibition of T-type Ca2+ channels. This signalling pathway provides a novel means by which proliferation of VSMCs (and other cells) may be regulated therapeutically.
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Affiliation(s)
- Hayley Duckles
- Division of Cardiovascular and Diabetes Research, LIGHT, Faculty of Medicine and Health, University of Leeds, Clarendon Way, Leeds, LS2 9JT, UK
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Parada E, Egea J, Buendia I, Negredo P, Cunha AC, Cardoso S, Soares MP, López MG. The microglial α7-acetylcholine nicotinic receptor is a key element in promoting neuroprotection by inducing heme oxygenase-1 via nuclear factor erythroid-2-related factor 2. Antioxid Redox Signal 2013; 19:1135-48. [PMID: 23311871 PMCID: PMC3785807 DOI: 10.1089/ars.2012.4671] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIMS We asked whether the neuroprotective effect of cholinergic microglial stimulation during an ischemic event acts via a mechanism involving the activation of nuclear factor erythroid-2-related factor 2 (Nrf2) and/or the expression of its target cytoprotective gene, heme oxygenase-1 (HO-1). Specifically, the protective effect of the pharmacologic alpha-7 nicotinic acetylcholine receptor (α7 nAChR) agonist PNU282987 was analyzed in organotypic hippocampal cultures (OHCs) subjected to oxygen and glucose deprivation (OGD) in vitro as well as in photothrombotic stroke in vivo. RESULTS OHCs exposed to OGD followed by reoxygenation elicited cell death, measured by propidium iodide and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide staining. Activation of α7 nAChR by PNU282987, after OGD, reduced cell death, reactive oxygen species production, and tumor necrosis factor release. This was associated with induction of HO-1 expression, an effect reversed by α-bungarotoxin and by tin-protoporphyrin IX. The protective effect of PNU282987 was lost in microglial-depleted OHCs as well as in OHCs from Nrf2-deficient-versus-wild-type mice, an effect associated with suppression of HO-1 expression in microglia. Administration of PNU282987 1 h after induction of photothrombotic stroke in vivo reduced the infarct size and improved motor skills in Hmox1(lox/lox) mice that express normal levels of HO-1, but not in LysM(Cre)Hmox1(Δ/Δ) in which HO-1 expression is inhibited in myeloid cells, including the microglia. INNOVATION This study suggests the participation of the microglial α7 nAChR in the brain cholinergic anti-inflammatory pathway. CONCLUSION Activation of the α7 nAChR/Nrf2/HO-1 axis in microglia regulates neuroinflammation and oxidative stress, affording neuroprotection under brain ischemic conditions.
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Affiliation(s)
- Esther Parada
- 1 Instituto Teófilo Hernando and Department of Pharmacology, School of Medicine, Universidad Autónoma de Madrid , Madrid, Spain
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Belhaj A, Dewachter L, Kerbaul F, Brimioulle S, Dewachter C, Naeije R, Rondelet B. Heme oxygenase-1 and inflammation in experimental right ventricular failure on prolonged overcirculation-induced pulmonary hypertension. PLoS One 2013; 8:e69470. [PMID: 23936023 PMCID: PMC3723896 DOI: 10.1371/journal.pone.0069470] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 06/10/2013] [Indexed: 01/30/2023] Open
Abstract
Heme oxygenase (HO)-1 is a stress response enzyme which presents with cardiovascular protective and anti-inflammatory properties. Six-month chronic overcirculation-induced pulmonary arterial hypertension (PAH) in piglets has been previously reported as a model of right ventricular (RV) failure related to the RV activation of apoptotic and inflammatory processes. We hypothesized that altered HO-1 signalling could be involved in both pulmonary vascular and RV changes. Fifteen growing piglets were assigned to a sham operation (n = 8) or to an anastomosis of the left innominate artery to the pulmonary arterial trunk (n = 7). Six months later, hemodynamics was evaluated after closure of the shunt. After euthanasia of the animals, pulmonary and myocardial tissue was sampled for pathobiological evaluation. Prolonged shunting was associated with a tendency to decreased pulmonary gene and protein expressions of HO-1, while pulmonary gene expressions of interleukin (IL)-33, IL-19, intercellular adhesion molecule (ICAM)-1 and -2 were increased. Pulmonary expressions of constitutive HO-2 and pro-inflammatory tumor necrosis factor (TNF)-α remained unchanged. Pulmonary vascular resistance (evaluated by pressure/flow plots) was inversely correlated to pulmonary HO-1 protein and IL-19 gene expressions, and correlated to pulmonary ICAM-1 gene expression. Pulmonary arteriolar medial thickness and PVR were inversely correlated to pulmonary IL-19 expression. RV expression of HO-1 was decreased, while RV gene expressions TNF-α and ICAM-2 were increased. There was a correlation between RV ratio of end-systolic to pulmonary arterial elastances and RV HO-1 expression. These results suggest that downregulation of HO-1 is associated to PAH and RV failure.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD/immunology
- Disease Models, Animal
- Down-Regulation
- Familial Primary Pulmonary Hypertension
- Gene Expression
- Heme Oxygenase-1/genetics
- Heme Oxygenase-1/immunology
- Hemodynamics
- Hypertension, Pulmonary/complications
- Hypertension, Pulmonary/genetics
- Hypertension, Pulmonary/immunology
- Hypertension, Pulmonary/physiopathology
- Inflammation/complications
- Inflammation/genetics
- Inflammation/immunology
- Inflammation/physiopathology
- Intercellular Adhesion Molecule-1/genetics
- Intercellular Adhesion Molecule-1/immunology
- Interleukins/genetics
- Interleukins/immunology
- Signal Transduction
- Swine
- Tumor Necrosis Factor-alpha/genetics
- Tumor Necrosis Factor-alpha/immunology
- Ventricular Dysfunction, Right/complications
- Ventricular Dysfunction, Right/genetics
- Ventricular Dysfunction, Right/immunology
- Ventricular Dysfunction, Right/physiopathology
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Affiliation(s)
- Asmae Belhaj
- Laboratory of Physiology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
- Service de Chirurgie Cardiovasculaire et Thoracique, Hôpital Mont-Godinne, Université Catholique de Louvain, Yvoir, Belgium
- Service de Chirurgie Thoracique, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Laurence Dewachter
- Laboratory of Physiology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - François Kerbaul
- Laboratory of Physiology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
- Département d’Anesthésie et Réanimation, Hôpital La Timone, Université de Marseille, Marseille, France
| | - Serge Brimioulle
- Laboratory of Physiology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
- Service des Soins Intensifs, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Céline Dewachter
- Laboratory of Physiology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Robert Naeije
- Laboratory of Physiology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Benoît Rondelet
- Laboratory of Physiology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
- Service de Chirurgie Cardiovasculaire et Thoracique, Hôpital Mont-Godinne, Université Catholique de Louvain, Yvoir, Belgium
- Service de Chirurgie Thoracique, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
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Song S, Wang S, Ma J, Yao L, Xing H, Zhang L, Liao L, Zhu D. Biliverdin reductase/bilirubin mediates the anti-apoptotic effect of hypoxia in pulmonary arterial smooth muscle cells through ERK1/2 pathway. Exp Cell Res 2013; 319:1973-1987. [PMID: 23722043 DOI: 10.1016/j.yexcr.2013.05.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 05/13/2013] [Accepted: 05/14/2013] [Indexed: 10/26/2022]
Abstract
Inhibition of pulmonary arterial smooth muscle cell (PASMC) apoptosis induced by hypoxia plays an important role in pulmonary arterial remodeling leading to aggravate hypoxic pulmonary arterial hypertension. However, the mechanisms of hypoxia acting on PASMC apoptosis remain exclusive. Biliverdin reductase (BVR) has many essential biologic roles in physiological and pathological processes. Nevertheless, it is unclear whether the hypoxia-induced inhibition on PASMC apoptosis is mediated by BVR. In the present work, we found BVR majorly localized in PASMCs and was up-regulated in levels of protein and mRNA by hypoxia. Then we studied the contribution of BVR to anti-apoptotic response of hypoxia in PASMCs. Our results showed that siBVR, blocking generation of bilirubin, reversed the effect of hypoxia on enhancing cell survival and apoptotic protein (Bcl-2, procasepase-9, procasepase-3) expression, preventing nuclear shrinkage, DNA fragmentation and mitochondrial depolarization in starved PASMCs, which were recovered by exogenous bilirubin. Moreover, the inhibitory effect of bilirubin on PASMC apoptosis under hypoxic condition was blocked by the inhibitor of ERK1/2 pathway. Taken together, our data indicate that BVR contributes to the inhibitory process of hypoxia on PASMC apoptosis, which is mediated by bilirubin through ERK1/2 pathway.
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Affiliation(s)
- Shasha Song
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319, China
| | - Shuang Wang
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319, China; Biopharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150081, China
| | - Jun Ma
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319, China
| | - Lan Yao
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319, China
| | - Hao Xing
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319, China
| | - Lei Zhang
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319, China
| | - Lin Liao
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319, China
| | - Daling Zhu
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319, China; Biopharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150081, China.
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Lee C, Mitsialis SA, Aslam M, Vitali SH, Vergadi E, Konstantinou G, Sdrimas K, Fernandez-Gonzalez A, Kourembanas S. Exosomes mediate the cytoprotective action of mesenchymal stromal cells on hypoxia-induced pulmonary hypertension. Circulation 2012; 126:2601-11. [PMID: 23114789 DOI: 10.1161/circulationaha.112.114173] [Citation(s) in RCA: 600] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Hypoxia induces an inflammatory response in the lung manifested by alternative activation of macrophages with elevation of proinflammatory mediators that are critical for the later development of hypoxic pulmonary hypertension. Mesenchymal stromal cell transplantation inhibits lung inflammation, vascular remodeling, and right heart failure and reverses hypoxic pulmonary hypertension in experimental models of disease. In this study, we aimed to investigate the paracrine mechanisms by which mesenchymal stromal cells are protective in hypoxic pulmonary hypertension. METHODS AND RESULTS We fractionated mouse mesenchymal stromal cell-conditioned media to identify the biologically active component affecting in vivo hypoxic signaling and determined that exosomes, secreted membrane microvesicles, suppressed the hypoxic pulmonary influx of macrophages and the induction of proinflammatory and proproliferative mediators, including monocyte chemoattractant protein-1 and hypoxia-inducible mitogenic factor, in the murine model of hypoxic pulmonary hypertension. Intravenous delivery of mesenchymal stromal cell-derived exosomes (MEX) inhibited vascular remodeling and hypoxic pulmonary hypertension, whereas MEX-depleted media or fibroblast-derived exosomes had no effect. MEX suppressed the hypoxic activation of signal transducer and activator of transcription 3 (STAT3) and the upregulation of the miR-17 superfamily of microRNA clusters, whereas it increased lung levels of miR-204, a key microRNA, the expression of which is decreased in human pulmonary hypertension. MEX produced by human umbilical cord mesenchymal stromal cells inhibited STAT3 signaling in isolated human pulmonary artery endothelial cells, demonstrating a direct effect of MEX on hypoxic vascular cells. CONCLUSION This study indicates that MEX exert a pleiotropic protective effect on the lung and inhibit pulmonary hypertension through suppression of hyperproliferative pathways, including STAT3-mediated signaling induced by hypoxia.
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Affiliation(s)
- Changjin Lee
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
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13
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Anversa P, Perrella MA, Kourembanas S, Choi AMK, Loscalzo J. Regenerative pulmonary medicine: potential and promise, pitfalls and challenges. Eur J Clin Invest 2012; 42:900-13. [PMID: 22435680 PMCID: PMC3513384 DOI: 10.1111/j.1365-2362.2012.02667.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Chronic lung diseases contribute significantly to the morbidity and mortality of the population. There are few effective treatments for many chronic lung diseases, and even fewer therapies that can arrest or reverse the progress of the disease. DESIGN In this review, we present the current state of regenerative therapies for the treatment of chronic lung diseases. We focus on endothelial progenitor cells, mesenchymal stem cells, and endogenous lung stem/progenitor cells; summarize the work to date in models of lung diseases for each of these therapies; and consider their potential benefits and risks as viable therapies for patients with lung diseases. CONCLUSIONS Cell-based regenerative therapies for lung diseases offer great promise, with preclinical studies suggesting that the next decade should provide the evidence necessary for their ultimate application to our therapeutic armamentarium.
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Affiliation(s)
- Piero Anversa
- Brigham and Women's Hospital Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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14
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Cheng C, Haasdijk RA, Tempel D, den Dekker WK, Chrifi I, Blonden LAJ, van de Kamp EHM, de Boer M, Bürgisser PE, Noorderloos A, Rens JAP, ten Hagen TLM, Duckers HJ. PDGF-induced migration of vascular smooth muscle cells is inhibited by heme oxygenase-1 via VEGFR2 upregulation and subsequent assembly of inactive VEGFR2/PDGFRβ heterodimers. Arterioscler Thromb Vasc Biol 2012; 32:1289-98. [PMID: 22426130 DOI: 10.1161/atvbaha.112.245530] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE In cardiovascular regulation, heme oxygenase-1 (HO-1) activity has been shown to inhibit vascular smooth muscle cell (VSMC) proliferation by promoting cell cycle arrest at the G1/S phase. However, the effect of HO-1 on VSMC migration remains unclear. We aim to elucidate the mechanism by which HO-1 regulates PDGFBB-induced VSMC migration. METHODS AND RESULTS Transduction of HO-1 cDNA adenoviral vector severely impeded human VSMC migration in a scratch, transmembrane, and directional migration assay in response to PDGFBB stimulation. Similarly, HO-1 overexpression in the remodeling process during murine retinal vasculature development attenuated VSMC coverage over the major arterial branches as compared with sham vector-transduced eyes. HO-1 expression in VSMCs significantly upregulated VEGFA and VEGFR2 expression, which subsequently promoted the formation of inactive PDGFRβ/VEGFR2 complexes. This compromised PDGFRβ phosphorylation and impeded the downstream cascade of FAK-p38 signaling. siRNA-mediated silencing of VEGFA or VEGFR2 could reverse the inhibitory effect of HO-1 on VSMC migration. CONCLUSIONS These findings identify a potent antimigratory function of HO-1 in VSMCs, a mechanism that involves VEGFA and VEGFR2 upregulation, followed by assembly of inactive VEGFR2/PDGFRβ complexes that attenuates effective PDGFRβ signaling.
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Affiliation(s)
- Caroline Cheng
- Molecular Cardiology Laboratory, Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands
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15
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Christou H, Reslan OM, Mam V, Tanbe AF, Vitali SH, Touma M, Arons E, Mitsialis SA, Kourembanas S, Khalil RA. Improved pulmonary vascular reactivity and decreased hypertrophic remodeling during nonhypercapnic acidosis in experimental pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2012; 302:L875-90. [PMID: 22287610 DOI: 10.1152/ajplung.00293.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Pulmonary hypertension (PH) is characterized by pulmonary arteriolar remodeling with excessive pulmonary vascular smooth muscle cell (VSMC) proliferation. This results in decreased responsiveness of pulmonary circulation to vasodilator therapies. We have shown that extracellular acidosis inhibits VSMC proliferation and migration in vitro. Here we tested whether induction of nonhypercapnic acidosis in vivo ameliorates PH and the underlying pulmonary vascular remodeling and dysfunction. Adult male Sprague-Dawley rats were exposed to hypoxia (8.5% O(2)) for 2 wk, or injected subcutaneously with monocrotaline (MCT, 60 mg/kg) to develop PH. Acidosis was induced with NH(4)Cl (1.5%) in the drinking water 5 days prior to and during the 2 wk of hypoxic exposure (prevention protocol), or after MCT injection from day 21 to 28 (reversal protocol). Right ventricular systolic pressure (RVSP) and Fulton's index were measured, and pulmonary arteriolar remodeling was analyzed. Pulmonary and mesenteric artery contraction to phenylephrine (Phe) and high KCl, and relaxation to acetylcholine (ACh) and sodium nitroprusside (SNP) were examined ex vivo. Hypoxic and MCT-treated rats demonstrated increased RVSP, Fulton's index, and pulmonary arteriolar thickening. In pulmonary arteries of hypoxic and MCT rats there was reduced contraction to Phe and KCl and reduced vasodilation to ACh and SNP. Acidosis prevented hypoxia-induced PH, reversed MCT-induced PH, and resulted in reduction in all indexes of PH including RVSP, Fulton's index, and pulmonary arteriolar remodeling. Pulmonary artery contraction to Phe and KCl was preserved or improved, and relaxation to ACh and SNP was enhanced in NH(4)Cl-treated PH animals. Acidosis alone did not affect the hemodynamics or pulmonary vascular function. Phe and KCl contraction and ACh and SNP relaxation were not different in mesenteric arteries of all groups. Thus nonhypercapnic acidosis ameliorates experimental PH, attenuates pulmonary arteriolar thickening, and enhances pulmonary vascular responsiveness to vasoconstrictor and vasodilator stimuli. Together with our finding that acidosis decreases VSMC proliferation, the results are consistent with the possibility that nonhypercapnic acidosis promotes differentiation of pulmonary VSMCs to a more contractile phenotype, which may enhance the effectiveness of vasodilator therapies in PH.
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Affiliation(s)
- Helen Christou
- Harvard Medical School, Brigham and Women's Hospital, Division of Vascular Surgery, Boston, MA 02115, USA
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16
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Fernandez-Gonzalez A, Alex Mitsialis S, Liu X, Kourembanas S. Vasculoprotective effects of heme oxygenase-1 in a murine model of hyperoxia-induced bronchopulmonary dysplasia. Am J Physiol Lung Cell Mol Physiol 2012; 302:L775-84. [PMID: 22287607 DOI: 10.1152/ajplung.00196.2011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Bronchopulmonary dysplasia (BPD) is characterized by simplified alveolarization and arrested vascular development of the lung with associated evidence of endothelial dysfunction, inflammation, increased oxidative damage, and iron deposition. Heme oxygenase-1 (HO-1) has been reported to be protective in the pathogenesis of diseases of inflammatory and oxidative etiology. Because HO-1 is involved in the response to oxidative stress produced by hyperoxia and is critical for cellular heme and iron homeostasis, it could play a protective role in BPD. Therefore, we investigated the effect of HO-1 in hyperoxia-induced lung injury using a neonatal transgenic mouse model with constitutive lung-specific HO-1 overexpression. Hyperoxia triggered an increase in pulmonary inflammation, arterial remodeling, and right ventricular hypertrophy that was attenuated by HO-1 overexpression. In addition, hyperoxia led to pulmonary edema, hemosiderosis, and a decrease in blood vessel number, all of which were markedly improved in HO-1 overexpressing mice. The protective vascular response may be mediated at least in part by carbon monoxide, due to its anti-inflammatory, antiproliferative, and antiapoptotic properties. HO-1 overexpression, however, did not prevent alveolar simplification nor altered the levels of ferritin and lactoferrin, proteins involved in iron binding and transport. Thus the protective mechanisms elicited by HO-1 overexpression primarily preserve vascular growth and barrier function through iron-independent, antioxidant, and anti-inflammatory pathways.
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17
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Digoxin inhibits development of hypoxic pulmonary hypertension in mice. Proc Natl Acad Sci U S A 2012; 109:1239-44. [PMID: 22232678 DOI: 10.1073/pnas.1120385109] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chronic hypoxia is an inciting factor for the development of pulmonary arterial hypertension. The mechanisms involved in the development of hypoxic pulmonary hypertension (HPH) include hypoxia-inducible factor 1 (HIF-1)-dependent transactivation of genes controlling pulmonary arterial smooth muscle cell (PASMC) intracellular calcium concentration ([Ca(2+)](i)) and pH. Recently, digoxin was shown to inhibit HIF-1 transcriptional activity. In this study, we tested the hypothesis that digoxin could prevent and reverse the development of HPH. Mice were injected daily with saline or digoxin and exposed to room air or ambient hypoxia for 3 wk. Treatment with digoxin attenuated the development of right ventricle (RV) hypertrophy and prevented the pulmonary vascular remodeling and increases in PASMC [Ca(2+)](i), pH, and RV pressure that occur in mice exposed to chronic hypoxia. When started after pulmonary hypertension was established, digoxin attenuated the hypoxia-induced increases in RV pressure and PASMC pH and [Ca(2+)](i). These preclinical data support a role for HIF-1 inhibitors in the treatment of HPH.
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18
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Liang OD, Mitsialis SA, Chang MS, Vergadi E, Lee C, Aslam M, Fernandez-Gonzalez A, Liu X, Baveja R, Kourembanas S. Mesenchymal stromal cells expressing heme oxygenase-1 reverse pulmonary hypertension. Stem Cells 2011; 29:99-107. [PMID: 20957739 DOI: 10.1002/stem.548] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Pulmonary arterial hypertension (PAH) remains a serious disease, and although current treatments may prolong and improve quality of life, search for novel and effective therapies is warranted. Using genetically modified mouse lines, we tested the ability of bone marrow-derived stromal cells (mesenchymal stem cells [MSCs]) to treat chronic hypoxia-induced PAH. Recipient mice were exposed for 5 weeks to normobaric hypoxia (8%-10% O(2)), MSC preparations were delivered through jugular vein injection and their effect on PAH was assessed after two additional weeks in hypoxia. Donor MSCs derived from wild-type (WT) mice or heme oxygenase-1 (HO-1) null mice (Hmox1(KO)) conferred partial protection from PAH when transplanted into WT or Hmox1(KO) recipients, whereas treatment with MSCs isolated from transgenic mice harboring a human HO-1 transgene under the control of surfactant protein C promoter (SH01 line) reversed established disease in WT recipients. SH01-MSC treatment of Hmox1(KO) animals, which develop right ventricular (RV) infarction under prolonged hypoxia, resulted in normal RV systolic pressure, significant reduction of RV hypertrophy and prevention of RV infarction. Donor MSCs isolated from a bitransgenic mouse line with doxycycline-inducible, lung-specific expression of HO-1 exhibited similar therapeutic efficacy only on doxycycline treatment of the recipients. In vitro experiments indicate that potential mechanisms of MSC action include modulation of hypoxia-induced lung inflammation and inhibition of smooth muscle cell proliferation. Cumulatively, our results demonstrate that MSCs ameliorate chronic hypoxia-induced PAH and their efficacy is highly augmented by lung-specific HO-1 expression in the transplanted cells, suggesting an interplay between HO-1-dependent and HO-1-independent protective pathways.
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Affiliation(s)
- Olin D Liang
- Division of Newborn Medicine, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA
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19
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Vergadi E, Chang MS, Lee C, Liang OD, Liu X, Fernandez-Gonzalez A, Mitsialis SA, Kourembanas S. Early macrophage recruitment and alternative activation are critical for the later development of hypoxia-induced pulmonary hypertension. Circulation 2011; 123:1986-95. [PMID: 21518986 DOI: 10.1161/circulationaha.110.978627] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Lung inflammation precedes the development of hypoxia-induced pulmonary hypertension (HPH); however, its role in the pathogenesis of HPH is poorly understood. We sought to characterize the hypoxic inflammatory response and to elucidate its role in the development of HPH. We also aimed to investigate the mechanisms by which heme oxygenase-1, an anti-inflammatory enzyme, is protective in HPH. METHODS AND RESULTS We generated bitransgenic mice that overexpress human heme oxygenase-1 under doxycycline control in an inducible, lung-specific manner. Hypoxic exposure of mice in the absence of doxycycline resulted in early transient accumulation of monocytes/macrophages in the bronchoalveolar lavage. Alveolar macrophages acquired an alternatively activated phenotype (M2) in response to hypoxia, characterized by the expression of found in inflammatory zone-1, arginase-1, and chitinase-3-like-3. A brief 2-day pulse of doxycycline delayed, but did not prevent, the peak of hypoxic inflammation, and could not protect against HPH. In contrast, a 7-day doxycycline treatment sustained high heme oxygenase-1 levels during the entire period of hypoxic inflammation, inhibited macrophage accumulation and activation, induced macrophage interleukin-10 expression, and prevented the development of HPH. Supernatants from hypoxic M2 macrophages promoted the proliferation of pulmonary artery smooth muscle cells, whereas treatment with carbon monoxide, a heme oxygenase-1 enzymatic product, abrogated this effect. CONCLUSIONS Early recruitment and alternative activation of macrophages in hypoxic lungs are critical for the later development of HPH. Heme oxygenase-1 may confer protection from HPH by effectively modifying the macrophage activation state in hypoxia.
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Affiliation(s)
- Eleni Vergadi
- Division of Newborn Medicine, Children's Hospital Boston, Harvard Medical School, MA 02115, USA
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20
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Mam V, Tanbe AF, Vitali SH, Arons E, Christou HA, Khalil RA. Impaired vasoconstriction and nitric oxide-mediated relaxation in pulmonary arteries of hypoxia- and monocrotaline-induced pulmonary hypertensive rats. J Pharmacol Exp Ther 2009; 332:455-62. [PMID: 19915069 DOI: 10.1124/jpet.109.160119] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pulmonary hypertension (PH) is a life-threatening disease with unclear vascular mechanisms. We tested whether PH involves abnormal pulmonary vasoconstriction and impaired vasodilation. Male Sprague-Dawley rats were exposed to hypoxia (9% O(2)) for 2 weeks or injected with single dose of monocrotaline (MCT, 60 mg/kg s.c.). Control rats were normoxic or injected with saline. After the hemodynamic measurements were performed, pulmonary and mesenteric arteries were isolated for measurement of vascular function. Hematocrit was elevated in hypoxic rats. Right ventricular systolic pressure and Fulton's Index [right/(left + septum) ventricular weight] were greater in hypoxic and MCT-treated rats than in normoxic rats. Pulmonary artery contraction by phenylephrine and 96 mM KCl was less in hypoxic and MCT-treated rats than in normoxic rats. Acetylcholine-induced relaxation was less in the pulmonary arteries of hypoxic and MCT-treated rats than of normoxic rats, suggesting reduced effects of endothelium-derived vasodilators. The nitric oxide synthase inhibitor, N(omega)-nitro-l-arginine methyl ester, and the guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, inhibited acetylcholine relaxation, suggesting that it was mediated by nitric oxide (NO)-cGMP. The NO donor sodium nitroprusside caused less relaxation in the pulmonary arteries of hypoxic and MCT-treated than of normoxic rats, suggesting decreased responsiveness of vascular smooth muscle cells (VSMCs) to vasodilators. Phenylephrine and KCl contraction and acetylcholine and sodium nitroprusside relaxation were not different in the mesenteric arteries from all groups. In lung tissue sections, the wall thickness of pulmonary arterioles was greater in hypoxic and MCT-treated rats than in normoxic rats. The specific reductions in pulmonary, but not systemic, arterial vasoconstriction and vasodilation in hypoxia- and MCT-induced PH are consistent with the possibility of de-differentiation of pulmonary VSMCs to a more proliferative/synthetic and less contractile phenotype in PH.
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Affiliation(s)
- Virak Mam
- Division of Vascular Surgery, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA
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