151
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Bayir H, Kagan VE. Bench-to-bedside review: Mitochondrial injury, oxidative stress and apoptosis--there is nothing more practical than a good theory. Crit Care 2008; 12:206. [PMID: 18341705 PMCID: PMC2374589 DOI: 10.1186/cc6779] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Apoptosis contributes to cell death in common intensive care unit disorders such as traumatic brain injury and sepsis. Recent evidence suggests that this form of cell death is both clinically relevant and a potential therapeutic target in critical illness. Mitochondrial reactive oxygen species (ROS) have become a target for drug discovery in recent years since their production is characteristic of early stages of apoptosis. Among many antioxidant agents, stable nitroxide radicals targeted to mitochondria have attracted attention due to their ability to combine electron and free radical scavenging action with recycling capacities. Specific mechanisms of enhanced ROS generation in mitochondria and their translation into apoptotic signals are not well understood. This review focuses on several contemporary aspects of oxidative stress-mediated mitochondrial injury, particularly as they relate to oxidation of lipids and their specific signaling roles in apoptosis and phagocytosis of apoptotic cells.
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Affiliation(s)
- Hülya Bayir
- Safar Center for Resuscitation Research, Department of Critical Care Medicine, School of Medicine, University of Pittsburgh, PA, USA.
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152
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Churg A, Cosio M, Wright JL. Mechanisms of cigarette smoke-induced COPD: insights from animal models. Am J Physiol Lung Cell Mol Physiol 2008; 294:L612-31. [PMID: 18223159 DOI: 10.1152/ajplung.00390.2007] [Citation(s) in RCA: 222] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cigarette smoke-induced animal models of chronic obstructive pulmonary disease support the protease-antiprotease hypothesis of emphysema, although which cells and proteases are the crucial actors remains controversial. Inhibition of either serine or metalloproteases produces significant protection against emphysema, but inhibition is invariably accompanied by decreases in the inflammatory response to cigarette smoke, suggesting that these inhibitors do more than just prevent matrix degradation. Direct anti-inflammatory interventions are also effective against the development of emphysema, as are antioxidant strategies; the latter again decrease smoke-induced inflammation. There is increasing evidence for autoimmunity, perhaps directed against matrix components, as a driving force in emphysema. There is intriguing but controversial animal model evidence that failure to repair/failure of lung maintenance also plays a role in the pathogenesis of emphysema. Cigarette smoke produces small airway remodeling in laboratory animals, possibly by direct induction of fibrogenic growth factors in the airway wall, and also produces pulmonary hypertension, at least in part through direct upregulation of vasoactive mediators in the intrapulmonary arteries. Smoke exposure causes goblet cell metaplasia and excess mucus production in the small airways and proximal trachea, but these changes are not good models of either chronic bronchitis or acute exacerbations. Emphysema, small airway remodeling, pulmonary hypertension, and mucus production appear to be at least partially independent processes that may require different therapeutic approaches.
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Affiliation(s)
- Andrew Churg
- Department of Pathology, University of British Columbia, Vancouver, British Columbia, Canada.
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153
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Henson PM, Tuder RM. Apoptosis in the lung: induction, clearance and detection. Am J Physiol Lung Cell Mol Physiol 2008; 294:L601-11. [PMID: 18178675 DOI: 10.1152/ajplung.00320.2007] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Apoptosis and other forms of programmed cell death are important contributors to lung pathophysiology. In this brief review, we discuss some of the implications of finding apoptotic cells in the lung and methods for their detection. The balance between induction of apoptosis and the normally highly efficient clearance of such cells shows that these are highly dynamic processes and suggests that abnormalities of apoptotic cell clearance may be an alternative explanation for their detection. Because recognition of apoptotic cells by other lung cells has additional effects on inflammation, immunity, and tissue repair, local responses to the dying cells may also have important consequences in addition to the cell death itself.
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Affiliation(s)
- P M Henson
- Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206, USA.
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154
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Lipid homeostasis in macrophages – Implications for atherosclerosis. REVIEWS OF PHYSIOLOGY BIOCHEMISTRY AND PHARMACOLOGY 2008; 160:93-125. [DOI: 10.1007/112_2008_802] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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155
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Revascularization of Wounds: The Oxygen-Hypoxia Paradox. Angiogenesis 2008. [DOI: 10.1007/978-0-387-71518-6_46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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156
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Defective apoptotic cell clearance in asthma and COPD--a new drug target for statins? Trends Pharmacol Sci 2007; 29:6-11. [PMID: 18054798 DOI: 10.1016/j.tips.2007.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 10/08/2007] [Accepted: 11/19/2007] [Indexed: 10/22/2022]
Abstract
Asthma and chronic obstructive pulmonary disease represent increasingly common respiratory conditions with a clear unmet need for more effective and safer therapy. Airway inflammation is key to both asthma pathogenesis and exacerbations of symptoms in chronic obstructive pulmonary disease. Several lines of evidence are now emerging implicating the increased persistence of apoptotic cells in patients with chronic inflammatory lung diseases and that this is largely due to a combination of inhibition of, or defects in, the apoptotic process and/or impaired apoptotic cell removal mechanisms.
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157
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Cazzola M, Ciaprini C, Page CP, Matera MG. Targeting systemic inflammation: novel therapies for the treatment of chronic obstructive pulmonary disease. Expert Opin Ther Targets 2007; 11:1273-86. [PMID: 17907958 DOI: 10.1517/14728222.11.10.1273] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The increasing evidence that inflammation in the lungs leads to the structural changes observed in chronic obstructive pulmonary disease, whereas extrapulmonary symptoms and comorbidities may be systemic manifestations of these inflammatory processes, highlights an urgent need to discover novel, effective anti-inflammatory treatments for this disease. Some studies are suggesting that, by decreasing dynamic hyperinflation, bronchodilators might reduce systemic inflammation; inhaled corticosteroids and their combination with long-acting beta2-agonists might contribute to this goal. Even so, the opinion that suppression of the inflammatory response might improve systemic complications is stimulating a search for novel anti-inflammatory therapies. Many drugs include those that inhibit the recruitment and activation of inflammatory cells and/or antagonise their products. However, many of these therapeutic strategies are not specific for neutrophilic inflammation because they affect other cell types, thus, it is difficult to interpret whether any clinical benefit observed is a result of a reduction in airway neutrophils. In any case, there is some evidence that drugs used to treat a co-morbid condition, such as statins, angiotensin converting enzyme (ACE) inhibitors and angiontensin II type 1 (AT1) receptor blockers as well as glycosaminoglycans and peroxisome proliferator-activated receptor (PPAR) agonists, might benefit chronic obstructive pulmonary disease patients because they deal with the extrapulmonary, systemic component of chronic obstructive pulmonary disease.
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Affiliation(s)
- Mario Cazzola
- Associate Professor of Respiratory Medicine, Universitá di Roma Tor Vergata, Dipartimento di Medicina Interna, Via Montpellier 1, 00133 Roma, Italy.
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158
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Bianchi SM, Prince LR, McPhillips K, Allen L, Marriott HM, Taylor GW, Hellewell PG, Sabroe I, Dockrell DH, Henson PW, Whyte MKB. Impairment of apoptotic cell engulfment by pyocyanin, a toxic metabolite of Pseudomonas aeruginosa. Am J Respir Crit Care Med 2007; 177:35-43. [PMID: 17916805 DOI: 10.1164/rccm.200612-1804oc] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Cystic fibrosis lung disease is characterized by accumulation of apoptotic neutrophils, indicating impaired clearance of dying cells. Pseudomonas aeruginosa, the principal microbial pathogen in cystic fibrosis, manipulates apoptosis induction via production of toxic metabolites. Whether these metabolites, particularly pyocyanin, can also modulate apoptotic cell engulfment is unknown. OBJECTIVES To assess the effects of pyocyanin on apoptotic cell engulfment by macrophages in vitro and in vivo and to investigate potential mechanisms of the observed effects. METHODS Human monocyte-derived macrophages were treated with pyocyanin before challenge with apoptotic neutrophils, apoptotic Jurkat cells, or latex beads, and phagocytosis was assessed by light microscopy and flow cytometry. Effects of pyocyanin production on apoptotic cell clearance in vivo were assessed in a murine model, comparing infection by wild-type or pyocyanin-deficient P. aeruginosa. Oxidant production was investigated using fluorescent probes and pharmacologic inhibition and Rho GTPase signaling by immunoblotting and inhibitor studies. MEASUREMENTS AND MAIN RESULTS Pyocyanin treatment impaired macrophage engulfment of apoptotic cells in vitro, without inducing significant macrophage apoptosis, whereas latex bead uptake was preserved. Macrophage ingestion of apoptotic cells was reduced and late apoptotic/necrotic cells were increased in mice infected with pyocyanin-producing P. aeruginosa compared with the pyocyanin-deficient strain. Inhibition of apoptotic cell uptake involved intracellular generation of reactive oxygen species (ROS) and effects on Rho GTPase signaling. Antioxidants or blockade of Rho signaling substantially restored apoptotic cell engulfment. CONCLUSIONS These studies demonstrate that P. aeruginosa can manipulate the inflammatory microenvironment through inhibition of apoptotic cell engulfment, and suggest potential strategies to limit pulmonary inflammation in cystic fibrosis.
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Affiliation(s)
- Stephen M Bianchi
- Academic Unit of Respiratory Medicine, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield S10 2JF, UK
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159
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Cazzola M, Matera MG, Rogliani P, Page C. Treating systemic effects of COPD. Trends Pharmacol Sci 2007; 28:544-50. [PMID: 17897727 DOI: 10.1016/j.tips.2007.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Accepted: 09/10/2007] [Indexed: 11/21/2022]
Abstract
The emerging recognition that chronic obstructive pulmonary disease (COPD) is a complex disorder, characterized not only by local pulmonary inflammation, but also by systemic inflammation that might have an adverse impact on various extrapulmonary organs, such as the blood vessels and the heart, among others, emphasizes the need for new and more effective forms of therapy for this debilitating disorder. Fortunately, many of the 'standard' therapeutic options used to treat COPD have the potential to influence systemic inflammation. Moreover, several new therapeutic strategies aimed at controlling the underlying inflammatory processes of COPD more specifically are under development. Unfortunately, we still do not know whether treatment of lung inflammation decreases, for example, the risk of acute cardiac events, progression of atherosclerosis or thrombotic events. It is also unclear whether, alternatively, treatment of heart disease can affect the progression of lung disease. Nonetheless, initial data seem to indicate that drugs, such as statins, ACE inhibitors, AT1 receptor blockers and PPAR agonists, used to treat a co-morbid condition have the potential to benefit COPD patients.
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Affiliation(s)
- Mario Cazzola
- Unit of Respiratory Diseases, Department of Internal Medicine, University of Rome Tor Vergata, Rome, Italy.
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160
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Minematsu N, Shapiro SD. To live and die in the LA (lung airway): mode of neutrophil death and progression of chronic obstructive pulmonary disease. Am J Respir Cell Mol Biol 2007; 37:129-30. [PMID: 17634347 DOI: 10.1165/rcmb.2007-0002ed] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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161
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Ishida W, Kajiwara T, Ishii M, Fujiwara F, Taneichi H, Takebe N, Takahashi K, Kaneko Y, Segawa I, Inoue H, Satoh J. Decrease in mortality rate of chronic obstructive pulmonary disease (COPD) with statin use: a population-based analysis in Japan. TOHOKU J EXP MED 2007; 212:265-73. [PMID: 17592214 DOI: 10.1620/tjem.212.265] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It has been well established that statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, reduce mortality from cardiovascular diseases. Statins, a class of cholesterol-lowering drug, may also affect mortality from various diseases by their pleiotropic effects of anti-inflammatory and anti-oxidative activities. However, there are only few reports concerning the effects of statins on diseases other than cardiovascular diseases. We therefore designed a population-based analysis, using the data from marketing surveys on statin sales and government reports on mortalities. We compared the statin use as expressed by statin sales per capita in the aged (> or = 65-year-old) population with mortality from major causes of death among 47 prefectures in Japan. As expected, there were significant negative correlations between statin sales per capita and mortality from cardiovascular diseases (p < 0.05). In addition, we found that there was a correlation between statin sales and the decrease in mortality from chronic obstructive pulmonary disease (COPD) (p < 0.0001), senility (p < 0.01), pneumonia (p < 0.05), accidents (p < 0.05), or all death causes (p < 0.05). However, statin sales were not associated with mortalities from renal failure, liver diseases, suicide, and malignant diseases. These results suggest a broad spectrum of beneficial effects of statins, including reduction of mortality rate of COPD as well as cardiovascular diseases. It will be worthy to confirm the protective effect of statins on COPD by prospective randomized clinical trials.
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Affiliation(s)
- Wataru Ishida
- Department of Diabetes and Metabolism, Iwate Medical University, Morioka, Japan
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162
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Muchova L, Wong RJ, Hsu M, Morioka I, Vitek L, Zelenka J, Schröder H, Stevenson DK. Statin treatment increases formation of carbon monoxide and bilirubin in mice: a novel mechanism of in vivo antioxidant protection. Can J Physiol Pharmacol 2007; 85:800-10. [PMID: 17901890 DOI: 10.1139/y07-077] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Heme oxygenase (HO) has a central role in cellular antioxidant defences and vascular protection, and it may mediate pleiotropic actions of drugs used in cardiovascular therapy. We investigated whether long-term use of statins upregulates HO activity and increases carbon monoxide (CO) and bilirubin levels in vivo. Adult FvB mice were given atorvastatin or rosuvastatin (5 mg/kg) daily by i.p. injections for 1, 2, or 3 weeks. HO activity, tissue CO, bilirubin, and antioxidant levels, total plasma bilirubin, and carboxyhemoglobin (COHb) were measured. Fold changes in heart HO activity significantly increased after 1, 2, and 3 weeks of atorvastatin (1.24 ± 0.06 (p ≤ 0.05); 1.29 ± 0.26 (p ≤ 0.03); 1.33 ± 0.08 (p < 0.01), respectively) and 2 and 3 weeks of rosuvastatin (1.23 ± 0.20 (p ≤ 0.03); 1.63 ± 0.42 (p < 0.01), respectively). Heart tissue CO and COHb levels also increased after 3 weeks with atorvastatin (1.30 ± 0.24 (p ≤ 0.05); 1.92 ± 0.17 (p ≤ 0.001), respectively) and rosuvastatin (1.47 ± 0.13 (p ≤ 0.004); 1.63 ± 0.12 (p ≤ 0.001), respectively). Significant increases in heart antioxidant levels were observed after statin treatment and corroborated by heart bilirubin content elevations. Antioxidant level increases were abolished by treatment with an HO inhibitor. These findings suggest that the induction of HO and the production of its products, CO and bilirubin, may be a mechanism by which statins exert antioxidant actions and confer cardioprotection in vivo.
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Affiliation(s)
- Lucie Muchova
- Department of Pediatrics, Stanford University School of Medicine, 300 Pasteur Drive, Rm. S230, Stanford, CA 94305-5208, USA
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163
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Yoshida T, Tuder RM. Pathobiology of cigarette smoke-induced chronic obstructive pulmonary disease. Physiol Rev 2007; 87:1047-82. [PMID: 17615396 DOI: 10.1152/physrev.00048.2006] [Citation(s) in RCA: 375] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chronic obstructive pulmonary diseases (COPD), comprised of pulmonary emphysema, chronic bronchitis, and structural and inflammatory changes of small airways, is a leading cause of morbidity and mortality in the world. A better understanding of the pathobiology of COPD is critical for the developing of novel therapies, as the majority of patients with the disease have little therapeutic options at the present time. The pathobiology of COPD encompasses multiple injurious processes including inflammation (excessive or inappropriate innate and adaptive immunity), cellular apoptosis, altered cellular and molecular alveolar maintenance program, abnormal cell repair, extracellular matrix destruction (protease and anti-protease imbalance), and oxidative stress (oxidant and antioxidant imbalance). These processes are triggered by urban and rural air pollutants and active and/or passive cigarette smoke and modified by cellular senescence and infection. A series of receptor-mediated signal transduction pathways are activated by reactive oxygen species and tobacco components, resulting in impairment of a variety of cell signaling and cytokine networks, subsequently leading to chronic airway responses with mucus production, airway remodeling, and alveolar destruction. The authors provide an updated insight into the molecular and cellular pathobiology of COPD based on human and/or animal data.
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Affiliation(s)
- Toshinori Yoshida
- Division of Cardiopulmonary Pathology, Department of Pathology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
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164
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Abstract
Chronic lung diseases like COPD, severe progressive pulmonary hypertension (PH), and interstitial lung diseases all have a lung vascular disease component. Cellular and molecular mechanisms of pulmonary vascular remodeling have been experimentally explored in many animal models, and it is now clear that microvessels are involved. In emphysema patients, there is a loss of lung microvessels, and in many forms of severe PH there is obliteration of precapillary arterioles by angioproliferation. Thus, COPD/emphysema and severe angioproliferative PH are on the opposite ends of a spectrum of vascular biology responses. Animal experiments have provided insight regarding some of the initiating events that shape the various forms of pulmonary vascular remodeling. In pulmonary fibrosis and in the postinjury phase of acute lung injury, the angiogenic/angiostatic balance is also affected. This review will therefore discuss angiogenesis in several chronic lung diseases and will speculate on how altered vascular homeostasis may contribute to lung disease development.
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Affiliation(s)
- Norbert F Voelkel
- The Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado at Denver Health Sciences Center, Denver CO.
| | - Ivor S Douglas
- The Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado at Denver Health Sciences Center, Denver CO
| | - Mark Nicolls
- The Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado at Denver Health Sciences Center, Denver CO
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165
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Sigal LH. Basic science for the clinician 42: handling the corpses: apoptosis, necrosis, nucleosomes and (quite possibly) the immunopathogenesis of SLE. J Clin Rheumatol 2007; 13:44-8. [PMID: 17278952 DOI: 10.1097/01.rhu.0000256288.09733.22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Death happens. It is, in essence, part of life. Humans deal with death in a variety of different ways, but often by keeping it at arms' length. At the cellular level, there are many forms of death, part of the development of organs and tissues (apoptosis) and part of pathologic processes (necrosis). The former, as has been described in an earlier paper in this series, is designed to eliminate the corpse with no evidence that it was ever there. Clearance is usually swift and effective, avoiding inflammation and specific immune interventions or responses. However, there is gathering evidence that autoimmunity leading to systemic lupus erythematosus may be due to ineffective or improper clearance of apoptotic debris, making it proinflammatory and allowing it to become highly immunogenic. This formulation also suggests therapeutic options that have already been demonstrated effective in controlling models of human autoimmune disease. This article reviews some aspects of this theory and some of the molecular biologic features of necrosis, apoptosis, and other forms of cell death.
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Affiliation(s)
- Leonard H Sigal
- Pharmaceutical Research Institute, Bristol-Myers Squibb, Princeton, NJ 08543-4000, USA.
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166
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Henson PM, Cosgrove GP, Vandivier RW. State of the art. Apoptosis and cell homeostasis in chronic obstructive pulmonary disease. Ann Am Thorac Soc 2006; 3:512-6. [PMID: 16921132 PMCID: PMC2647642 DOI: 10.1513/pats.200603-072ms] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Peter M Henson
- Department of Pediatrics, Division of Cell Biology, National Jewish Medical and Research Center, 1400 Jackson Street, Denver CO 80206, USA.
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167
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Jehle AW, Gardai SJ, Li S, Linsel-Nitschke P, Morimoto K, Janssen WJ, Vandivier RW, Wang N, Greenberg S, Dale BM, Qin C, Henson PM, Tall AR. ATP-binding cassette transporter A7 enhances phagocytosis of apoptotic cells and associated ERK signaling in macrophages. ACTA ACUST UNITED AC 2006; 174:547-56. [PMID: 16908670 PMCID: PMC2064260 DOI: 10.1083/jcb.200601030] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The mammalian ATP-binding cassette transporters A1 and A7 (ABCA1 and -A7) show sequence similarity to CED-7, a Caenorhabditis elegans gene that mediates the clearance of apoptotic cells. Using RNA interference or gene targeting, we show that knock down of macrophage ABCA7 but not -A1 results in defective engulfment of apoptotic cells. In response to apoptotic cells, ABCA7 moves to the macrophage cell surface and colocalizes with the low-density lipoprotein receptor–related protein 1 (LRP1) in phagocytic cups. The cell surface localization of ABCA7 and LRP1 is defective in ABCA7-deficient cells. C1q is an opsonin of apoptotic cells that acts via phagocyte LRP1 to induce extracellular signal–regulated kinase (ERK) signaling. We show that ERK signaling is required for phagocytosis of apoptotic cells and that ERK phosphorylation in response to apoptotic cells or C1q is defective in ABCA7-deficient cells. These studies reveal a major role of ABCA7 and not -A1 in the clearance of apoptotic cells and therefore suggest that ABCA7 is an authentic orthologue of CED-7.
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Affiliation(s)
- Andreas W Jehle
- Department of Medicine, Columbia University, New York, NY 10032, USA.
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168
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Vandivier RW, Henson PM, Douglas IS. Burying the dead: the impact of failed apoptotic cell removal (efferocytosis) on chronic inflammatory lung disease. Chest 2006; 129:1673-82. [PMID: 16778289 DOI: 10.1378/chest.129.6.1673] [Citation(s) in RCA: 329] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Apoptosis and the removal of apoptotic cells (termed efferocytosis) are tightly coupled with the regulation of normal lung structure, both in the developing and adult organism. Processes that disrupt or uncouple this balance have the potential to alter normal cell turnover, ultimately resulting in the induction of lung pathology and disease. Apoptotic cells are increased in several chronic inflammatory lung diseases, including cystic fibrosis (CF), non-CF bronchiectasis, COPD, and asthma. While this may well be due to the enhanced induction of apoptosis, increasing data suggest that the clearance of dying cells is also impaired. Because efferocytosis appears to be a key regulatory checkpoint for the innate immune system, the adaptive immune system, and cell proliferation, the failure of this highly conserved process may contribute to disease pathogenesis by impeding both the resolution of inflammation and the maintenance of alveolar integrity. The recognition of impaired efferocytosis as a contributor to chronic inflammation may ultimately direct us toward the identification of new disease biomarkers, as well as novel therapeutic approaches.
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Affiliation(s)
- R William Vandivier
- University of Colorado at Denver Health Sciences Center, COPD Center, Division of Pulmonary Sciences and Critical Care Medicine, 4200 E Ninth Ave, Box C272, Denver, CO 80220, USA.
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