451
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Kaczmarek A, Vandenabeele P, Krysko DV. Necroptosis: the release of damage-associated molecular patterns and its physiological relevance. Immunity 2013; 38:209-23. [PMID: 23438821 DOI: 10.1016/j.immuni.2013.02.003] [Citation(s) in RCA: 1093] [Impact Index Per Article: 99.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Indexed: 10/27/2022]
Abstract
Regulated necrosis, termed necroptosis, is negatively regulated by caspase-8 and is dependent on the kinase activity of RIPK1 and RIPK3. Necroptosis leads to rapid plasma membrane permeabilization and to the release of cell contents and exposure of damage-associated molecular patterns (DAMPs). We are only beginning to identify the necroptotic DAMPs, their modifications, and their potential role in the regulation of inflammation. In this review, we discuss the physiological relevance of necroptosis and its role in the modulation of inflammation. For example, during viral infection, RIPK3-mediated necroptosis acts as a backup mechanism to clear pathogens. Necroptosis is also involved in apparently immunologically silent maintenance of T cell homeostasis. In contrast, the induction of necroptosis in skin, intestine, systemic inflammatory response syndrome, and ischemia reperfusion injury provoke a strong inflammatory response, which might be triggered by emission of DAMPs from necroptotic cells, showing the detrimental side of necroptosis.
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Affiliation(s)
- Agnieszka Kaczmarek
- Molecular Signaling and Cell Death Unit, Department for Molecular Biomedical Research, VIB, 9052 Ghent, Belgium
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452
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Ouyang X, Ghani A, Mehal WZ. Inflammasome biology in fibrogenesis. Biochim Biophys Acta Mol Basis Dis 2013; 1832:979-88. [PMID: 23562491 DOI: 10.1016/j.bbadis.2013.03.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/20/2013] [Accepted: 03/23/2013] [Indexed: 12/20/2022]
Abstract
Pathogens and sterile insults both result in an inflammatory response. A significant part of this response is mediated by cytosolic machinery termed as the inflammasome which results in the activation and secretion of the cytokines interleukin-1β (IL-1β) and IL-18. Both of these are known to result in the activation of an acute inflammatory response, resulting in the production of downstream inflammatory cytokines such as tumor necrosis factor (TNF-α), interferon-gamma (IFN-γ), chemotaxis of immune cells, and induction of tissue injury. Surprisingly this very acute inflammatory pathway is also vital for the development of a full fibrogenic response in a number of organs including the lung, liver, and skin. There is evidence for the inflammasome having a direct role on tissue specific matrix producing cells such as the liver stellate cell, and also indirectly through the activation of resident tissue macrophage populations. The inflammasome requires stimulation of two pathways for full activation, and initiating stimuli include Toll-like receptor (TLR) agonists, adenosine triphosphate (ATP), particulates, and oxidative stress. Such a role for an acute inflammatory pathway in fibrosis runs counter to the prevailing association of TGF-β driven anti-inflammatory and pro-fibrotic pathways. This identifies new therapeutic targets which have the potential to simultaneously decrease inflammation, tissue injury and fibrosis. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.
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Affiliation(s)
- Xinshou Ouyang
- Section of Digestive Diseases, Yale University, New Haven, CT, USA; West Haven Veterans Medical Center, New Haven, CT, USA
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453
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Abstract
The classical Mendelian genetic perspective has failed to adequately explain the biology and genetics of common metabolic and degenerative diseases. This is because these diseases are primarily systemic bioenergetic diseases, and the most important energy genes are located in the cytoplasmic mitochondrial DNA (mtDNA). Therefore, to understand these "complex" diseases, we must investigate their bioenergetic pathophysiology and consider the genetics of the thousands of copies of maternally inherited mtDNA, the more than 1,000 nuclear DNA (nDNA) bioenergetic genes, and the epigenomic and signal transduction systems that coordinate these dispersed elements of the mitochondrial genome.
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Affiliation(s)
- Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-4302, USA.
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454
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Zager RA, Johnson AC, Becker K. Post-ischemic azotemia as a partial 'brake', slowing progressive kidney disease. Nephrol Dial Transplant 2013; 28:1455-62. [PMID: 23543590 DOI: 10.1093/ndt/gft040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Recent experimental work suggests a paradox: although uremia evokes systemic toxicities, in the setting of AKI, it can induce intrarenal cytoprotective and anti-inflammatory effects. Whether these influences can attenuate post-ischemic kidney disease progression remains unknown. METHODS To explore this possibility, male CD-1 mice were subjected to a 30-min unilateral (left) kidney ischemia model, previously shown to reduce renal mass by ∼50% over 2-3 weeks. Stepwise azotemia/acute uremia was superimposed by inducing different lengths of contralateral (right) kidney ischemia (0, 15, 18, 20 min). Subsequent loss of left renal mass (kidney weight) was assessed 2 weeks later and contrasted with the degree of initial azotemia 24-h BUN. RESULTS A striking correlation between 24-h BUNs and 2-week left renal mass was observed (r, 0.77; P < 0.001). With 20 min of right kidney ischemia, left kidney size was completely preserved. This preservation did not result from increased tubular cell proliferation or decreased microvascular loss, as gauged by KI-67 and CD-34 immunohistochemistry, respectively. Rather, an early reduction in proximal tubule cell dropout (as judged by renal cortical N-acetyl-glucosaminidase content), with a subsequent preservation of tubule mass, was observed. CONCLUSIONS In summary, these findings advance a novel concept: acute uremia can confer early post-ischemic cytoprotection resulting in a slowed progression of post-ischemic kidney disease.
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Affiliation(s)
- Richard A Zager
- Department of Medicine, University of Washington, and the Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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455
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Damage-associated molecular patterns derived from mitochondria may contribute to the hemodialysis-associated inflammation. Int Urol Nephrol 2013; 46:107-12. [PMID: 23515931 DOI: 10.1007/s11255-013-0417-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 03/11/2013] [Indexed: 01/08/2023]
Abstract
PURPOSE Inflammation is common in hemodialysis (HD) patients. Mitochondrial damage-associated molecular patterns (DAMPs) are released during cell necrosis or apoptosis and induce inflammation. Cell apoptosis is increased in HD patients. The mitochondrial protein cytochrome c, as a marker of released mitochondrial DAMPs, and interleukin-6 (IL-6), as a marker of inflammation, were evaluated in HD patients. METHODS Thirty-four HD patients and 20 controls were enrolled in the study. Serum cytochrome c and IL-6 were measured by means of enzyme-linked immunosorbent assay. RESULTS Compared to controls, cytochrome c was markedly increased in HD patients (1392.88 ± 905.24 pg/mL vs. 212.95 ± 91.71 pg/mL). IL-6 was also significantly increased in HD patients (50.32 ± 35.89 pg/mL vs. 14.27 ± 6.83 pg/mL). In HD patients serum IL-6 was positively related to serum cytochrome c (r = 0.458). CONCLUSION Both circulating cytochrome c and IL-6 are markedly increased in HD patients. Cytochrome c is positively related to IL-6.
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456
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Tintinger GR, Anderson R, Feldman C. Pharmacological approaches to regulate neutrophil activity. Semin Immunopathol 2013; 35:395-409. [PMID: 23494251 DOI: 10.1007/s00281-013-0366-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 02/07/2013] [Indexed: 12/14/2022]
Abstract
Although indispensable in host defense against microbial pathogens, misdirected hyperacute and chronic activation of neutrophils presents the potential hazard of tissue damage, organ dysfunction, and carcinogenesis. In many clinical settings, particularly inflammatory disorders of the airways, over-reactivity of neutrophils is exacerbated by their relative resistance to conventional, pharmacological anti-inflammatory therapies, including, but not limited to, corticosteroids. Notwithstanding their sheer numbers, which can increase rapidly and dramatically during inflammatory responses, these cells are not only pre-programmed to release reactive oxygen species, proteinases, and eicosanoids/prostanoids immediately on exposure to pro-inflammatory stimuli but may also subsequently undergo the process of netosis, thereby enhancing and protracting their inflammatory potential. All of these mechanisms are likely to underpin the resistance of neutrophils to pharmacological control and have triggered the search for alternatives to corticosteroids. In addition to macrolides and adenosine 3',5'-cyclic adenosine monophospate-elevating agents, more recent innovations in the control of neutrophilic inflammation include activators of histone deacetylases and antagonists of chemokine receptors, as well as monoclonal antibodies which target neutrophil-activating cytokines and their receptors. These and other neutrophil-targeted strategies represent the focus of the current review.
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Affiliation(s)
- G R Tintinger
- Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa.
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457
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Vanden Berghe T, Grootjans S, Goossens V, Dondelinger Y, Krysko DV, Takahashi N, Vandenabeele P. Determination of apoptotic and necrotic cell death in vitro and in vivo. Methods 2013; 61:117-29. [PMID: 23473780 DOI: 10.1016/j.ymeth.2013.02.011] [Citation(s) in RCA: 165] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/14/2013] [Accepted: 02/18/2013] [Indexed: 02/08/2023] Open
Abstract
Cell death research during the last decades has revealed many molecular signaling cascades, often leading to distinct cell death modalities followed by immune responses. For historical reasons, the prototypic and best characterized cell death modes are apoptosis and necrosis (dubbed necroptosis, to indicate that it is regulated). There is mounting evidence for the interplay between cell death modalities and their redundant action when one of them is interfered with. This increase in cell death research points to the need for characterizing cell death pathways by different approaches at the biochemical, cellular and if possible, physiological level. In this review we present a selection of techniques to detect cell death and to distinguish necrosis from apoptosis. The distinction should be based on pharmacologic and transgenic approaches in combination with several biochemical and morphological criteria. A particular problem in defining necrosis is that in the absence of phagocytosis, apoptotic cells become secondary necrotic and develop morphologic and biochemical features of primary necrosis.
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Affiliation(s)
- Tom Vanden Berghe
- Molecular Signaling and Cell Death Unit, Department for Molecular Biomedical Research, VIB, 9052 Ghent, Belgium
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458
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Han D, Dara L, Win S, Than TA, Yuan L, Abbasi SQ, Liu ZX, Kaplowitz N. Regulation of drug-induced liver injury by signal transduction pathways: critical role of mitochondria. Trends Pharmacol Sci 2013; 34:243-53. [PMID: 23453390 DOI: 10.1016/j.tips.2013.01.009] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/23/2013] [Accepted: 01/30/2013] [Indexed: 12/13/2022]
Abstract
Drugs that cause liver injury often 'stress' mitochondria and activate signal transduction pathways important in determining cell survival or death. In most cases, hepatocytes adapt to the drug-induced stress by activating adaptive signaling pathways, such as mitochondrial adaptive responses and nuclear factor erythroid 2-related factor 2 (Nrf-2), a transcription factor that upregulates antioxidant defenses. Owing to adaptation, drugs alone rarely cause liver injury, with acetaminophen (APAP) being the notable exception. Drug-induced liver injury (DILI) usually involves other extrinsic factors, such as the adaptive immune system, that cause 'stressed' hepatocytes to become injured, leading to idiosyncratic DILI, the rare and unpredictable adverse drug reaction in the liver. Hepatocyte injury, due to drug and extrinsic insult, causes a second wave of signaling changes associated with adaptation, cell death, and repair. If the stress and injury reach a critical threshold, then death signaling pathways such as c-Jun N-terminal kinase (JNK) become dominant and hepatocytes enter a failsafe mode to undergo self-destruction. DILI can be seen as an active process involving recruitment of death signaling pathways that mediate cell death rather than a passive process due to overwhelming biochemical injury. In this review, we highlight the role of signal transduction pathways, which frequently involve mitochondria, in the development of DILI.
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Affiliation(s)
- Derick Han
- University of Southern California Research Center for Liver Diseases and Southern California Research Center for ALPD, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9121, USA.
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459
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Doyle T, Esposito E, Bryant L, Cuzzocrea S, Salvemini D. NADPH-oxidase 2 activation promotes opioid-induced antinociceptive tolerance in mice. Neuroscience 2013; 241:1-9. [PMID: 23454539 DOI: 10.1016/j.neuroscience.2013.02.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 02/04/2013] [Accepted: 02/18/2013] [Indexed: 12/18/2022]
Abstract
The analgesic effectiveness of long-term opioid therapies is compromised by the development of antinociceptive tolerance linked to the overt production of peroxynitrite (ONOO(-), PN), the product of the interaction between superoxide (O2(-), SO) and nitric oxide (NO), and to neuroinflammatory processes. We have recently reported that in addition to post-translational nitration and inactivation of mitochondrial manganese superoxide dismutase (MnSOD), activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase holoenzyme (NOX) in the spinal cord is a major source for the overt production of superoxide-derived PN during the development of morphine-induced antinociceptive tolerance. However, the NOX complex involved in these processes is not known. The objective of these studies is to identify a potential role for the NOX2 complex, an enzyme involved in inflammation. Mice lacking the catalytic subunit of NOX2 (Nox2(-/-)) or its regulatory subunit, p47(phox) (p47(phox)(-/-)), developed antinociceptive tolerance similar to wildtype (wt) mice after 3 days of continuous morphine. However, while wt mice continue to develop tolerance by day six, morphine analgesia was restored in both Nox2(-/-) and p47(phox)(-/-) mice. Moreover, the loss of Nox2 or p47 did not affect acute morphine analgesia in naïve mice. In wt mice, antinociceptive tolerance was associated with increased activation of NOX, nitration of MnSOD, and proinflammatory cytokines production in the spinal cord. These events were markedly attenuated in Nox2(-/-) and p47(phox)(-/-) mice and instead, there was enhanced formation of antiinflammatory cytokine (IL4 and IL10) production. These results suggest that NOX2 activity provides a significant source of superoxide-derived PN to undertake post-translational modifications of mitochondrial MnSOD and to engage neuroinflammatory signaling in the spinal cord associated with opioid-induced antinociceptive tolerance. Thus, NOX2 may provide a potential target for adjuvant therapy to protect opioid analgesia.
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Affiliation(s)
- T Doyle
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St. Louis, MO 63104, USA
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460
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Zhang Q, Kang R, Zeh HJ, Lotze MT, Tang D. DAMPs and autophagy: cellular adaptation to injury and unscheduled cell death. Autophagy 2013; 9:451-8. [PMID: 23388380 DOI: 10.4161/auto.23691] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Autophagy is a lysosome-mediated catabolic process involving the degradation of intracellular contents (e.g., proteins and organelles) as well as invading microbes (e.g., parasites, bacteria and viruses). Multiple forms of cellular stress can stimulate this pathway, including nutritional imbalances, oxygen deprivation, immunological response, genetic defects, chromosomal anomalies and cytotoxic stress. Damage-associated molecular pattern molecules (DAMPs) are released by stressed cells undergoing autophagy or injury, and act as endogenous danger signals to regulate the subsequent inflammatory and immune response. A complex relationship exists between DAMPs and autophagy in cellular adaption to injury and unscheduled cell death. Since both autophagy and DAMPs are important for pathogenesis of human disease, it is crucial to understand how they interplay to sustain homeostasis in stressful or dangerous environments.
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Affiliation(s)
- Qiuhong Zhang
- Department of Surgery, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA, USA
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461
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Abstract
Toll-like receptor (TLR) signaling is a well-characterized, innate immune cellular defense mechanism used to detect and respond to pathogen-associated molecular patterns (PAMPs). TLR signaling is highly conserved and has evolved to have both extracellular and endosomal receptors that recognize PAMPs from a wide range of microbial pathogens. Recent literature has emerged to show that activation of TLRs not only leads to the upregulation of cellular defense mechanisms, but also results in upregulation of DNA repair genes and increased functional DNA repair. Endosomal TLR agonists result in increased survival and repair after both ionizing and UV radiation, suggesting that the repair pathways for single- and double-strand breaks are affected. This review brings together these and other experimental findings to examine how DNA repair pathways may be linked to TLR signaling. Also discussed are the varied outcomes and related physiological implications that increased DNA repair after injury might have.
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Affiliation(s)
- Erin Harberts
- Department of Molecular Microbiology and Immunology, University of Maryland Medical School, Baltimore
| | - Anthony Gaspari
- Department of Molecular Microbiology and Immunology, University of Maryland Medical School, Baltimore
- Department of Dermatology, University of Maryland, Baltimore
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462
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Krishnaswamy JK, Chu T, Eisenbarth SC. Beyond pattern recognition: NOD-like receptors in dendritic cells. Trends Immunol 2013; 34:224-33. [PMID: 23352728 DOI: 10.1016/j.it.2012.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 12/12/2012] [Accepted: 12/26/2012] [Indexed: 12/11/2022]
Abstract
Innate instruction of adaptive immunity was proposed more than 20 years ago as a mechanism by which long-lived lymphocyte responses are targeted to appropriate antigens. At the time Charles Janeway proposed this theory, most of the innate immune receptors were unknown, and the pivotal role of the dendritic cell in instructing T cell priming was debated. There is now overwhelming evidence that the innate and adaptive branches of the immune system must interact to generate immunity. Much of this work has focused on families of innate immune receptors called pattern recognition receptors (PRRs) on dendritic cells, which translate these inflammatory triggers into productive T cell responses. Nevertheless, we are only beginning to understand how these defence molecules shape the generation of immunity. We review the varied roles of one class of PRRs, the NOD-like receptors (NLRs), in immune responses and propose a new model in which adaptive immunity requires coordinated PRR activation within the dendritic cell.
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Affiliation(s)
- Jayendra Kumar Krishnaswamy
- Department of Laboratory Medicine, Section of Allergy and Immunology, Yale University School of Medicine, New Haven, CT 06520, USA
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463
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López-Armada MJ, Riveiro-Naveira RR, Vaamonde-García C, Valcárcel-Ares MN. Mitochondrial dysfunction and the inflammatory response. Mitochondrion 2013; 13:106-18. [PMID: 23333405 DOI: 10.1016/j.mito.2013.01.003] [Citation(s) in RCA: 354] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 11/30/2012] [Accepted: 01/07/2013] [Indexed: 12/18/2022]
Abstract
Inflammation has been linked to multiple degenerative and acute diseases as well as the aging process. Moreover, mitochondrial alterations play a central role in these processes. Mitochondria have an important role in pro-inflammatory signaling; similarly, pro-inflammatory mediators may also alter mitochondrial function. Both of these processes increase mitochondrial oxidative stress, promoting a vicious inflammatory cycle. Additionally, damage-associated molecular patterns derived from mitochondria could contribute to inflammasome formation and caspase-1 activation, while alterations in mitochondrial autophagy may cause inflammation. Strategies aimed at controlling excessive oxidative stress within mitochondria may represent both preventive and therapeutic interventions in inflammation.
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Affiliation(s)
- María J López-Armada
- Aging and Inflammation Research Laboratory, Instituto de Investigación Biomédica A Coruña (INIBIC)-Complexo Hospitalario Universitario A Coruña (CHUAC)-SERGAS, Xubias 84, 15006, A Coruña, Spain.
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464
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David BT, Ratnayake A, Amarante MA, Reddy NP, Dong W, Sampath S, Heary RF, Elkabes S. A toll-like receptor 9 antagonist reduces pain hypersensitivity and the inflammatory response in spinal cord injury. Neurobiol Dis 2013; 54:194-205. [PMID: 23313320 DOI: 10.1016/j.nbd.2012.12.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 11/11/2012] [Accepted: 12/28/2012] [Indexed: 12/20/2022] Open
Abstract
Toll-like receptors (TLRs) are mediators of the innate immune response to exogenous pathogens. They have also been implicated in sterile inflammation associated with systemic injury and non-infectious diseases via binding of endogenous ligands, possibly released by damaged cells. Emerging evidence indicates that some TLRs play a role in nervous system injury and especially in injury-elicited pain and sterile inflammation. However, no information is available about the contribution of TLR9, a member of the TLR family, to traumatic spinal cord injury (SCI). Moreover, the therapeutic potential of TLR9 ligands in the functional outcomes of SCI, including pain, has not been explored. We report, for the first time, that the intrathecal administration of a TLR9 antagonist, cytidine-phosphate-guanosine oligodeoxynucleotide 2088 (CpG ODN 2088), to mice sustaining a severe contusion SCI, diminishes injury-induced heat hypersensitivity. Investigations on the potential mechanisms underlying the reduction in pain sensitivity indicated an attenuation of the inflammatory reaction manifested by a decrease in the number of CD11b-, CD45- and CD3-immunoreactive cells and a reduction in tumor necrosis factor-α (TNF-α) expression at the epicenter. Conversely, intrathecal delivery of a TLR9 agonist, CpG ODN 1826, increased inflammatory cell numbers and TNF-α expression in the epicenter. The CpG ODN 2088 treatment did not appear to induce systemic adverse effects as shown by spleen histology and serum cytokine levels. We propose that CpG ODN 2088 dampens injury-induced heat hypersensitivity by suppressing the inflammatory response and TNF-α expression. This investigation defines a previously unreported therapeutic role for CpG ODN 2088 in SCI-induced pain.
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Affiliation(s)
- Brian T David
- Department of Neurological Surgery, New Jersey Medical School, Newark, NJ 07103, USA
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465
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Abstract
Chronic hyperglycemia (HG)-associated reactive oxygen/nitrogen species (ROS/RNS) stress and low grade inflammation are considered to play critical roles in the development of diabetic retinopathy (DR). Excess glucose metabolic flux through the aldose reductase/polyol pathway, advanced glycation end product (AGE) formation, elevated hexosamine biosynthesis pathway (HBP), diacyl glycerol/PKC activation, and mitochondrial ROS generation are all implicated in DR. In addition, endoplasmic reticulum stress/unfolded protein response (er-UPR) and deregulation of mitochondrial quality control by autophagy/mitophagy are observed causing cellular bioenergetic deficiency and injury. Recently, a pro-oxidant and pro-apoptotic thioredoxin interacting protein (TXNIP) was shown to be highly upregulated in DR and by HG in retinal cells in culture. TXNIP binds to thioredoxin (Trx) inhibiting its oxidant scavenging and thiolreducing capacity. Hence, prolonged overexpression of TXNIP causes ROS/RNS stress, mitochondrial dysfunction, inflammation and premature cell death in DR. Initially, DR was considered as microvascular complications of endothelial dysfunction and pericyte loss characterized by capillary basement membrane thickening, pericyte ghost, blood retinal barrier leakage, acellular capillary and neovascularization. However, it is currently acknowledged that neuro-glia are also affected by HG in diabetes and that neuronal injury, glial activation, innate immunity/sterile inflammation, and ganglion apoptosis occur early in DR. In addition, retinal pigment epithelium (RPE) becomes dysfunctional in DR. Since TXNIP is induced by HG in most cells, its effects are not restricted to a particular cell type in DR. However, depending on the metabolic activity and anti-oxidant capacity, some cells may be affected earlier by TXNIP than others. Identification of TXNIP sensitive cells and elucidating the underlying mechanism(s) will be critical for preventing pre-mature cell death and progression of DR.
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Affiliation(s)
- Lalit P Singh
- Departments of Anatomy and Cell Biology and Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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466
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Krysko DV, Garg AD, Kaczmarek A, Krysko O, Agostinis P, Vandenabeele P. Immunogenic cell death and DAMPs in cancer therapy. Nat Rev Cancer 2012; 12:860-75. [PMID: 23151605 DOI: 10.1038/nrc3380] [Citation(s) in RCA: 1919] [Impact Index Per Article: 159.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although it was thought that apoptotic cells, when rapidly phagocytosed, underwent a silent death that did not trigger an immune response, in recent years a new concept of immunogenic cell death (ICD) has emerged. The immunogenic characteristics of ICD are mainly mediated by damage-associated molecular patterns (DAMPs), which include surface-exposed calreticulin (CRT), secreted ATP and released high mobility group protein B1 (HMGB1). Most DAMPs can be recognized by pattern recognition receptors (PRRs). In this Review, we discuss the role of endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) in regulating the immunogenicity of dying cancer cells and the effect of therapy-resistant cancer microevolution on ICD.
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Affiliation(s)
- Dmitri V Krysko
- Molecular Signalling and Cell Death Unit, Department for Molecular Biomedical Research, VIB, VIB-Ghent University Technologiepark 927, B-9052 Ghent (Zwijnaarde), Belgium. Dmitri.Krysko@dmbr. ugent.be
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467
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Hill BG, Benavides GA, Lancaster JR, Ballinger S, Dell’Italia L, Zhang J, Darley-Usmar VM. Integration of cellular bioenergetics with mitochondrial quality control and autophagy. Biol Chem 2012; 393:1485-1512. [PMID: 23092819 PMCID: PMC3594552 DOI: 10.1515/hsz-2012-0198] [Citation(s) in RCA: 346] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 06/22/2012] [Indexed: 02/06/2023]
Abstract
Bioenergetic dysfunction is emerging as a cornerstone for establishing a framework for understanding the pathophysiology of cardiovascular disease, diabetes,cancer and neurodegeneration. Recent advances in cellular bioenergetics have shown that many cells maintain a substantial bioenergetic reserve capacity, which is a prospective index of ‘ healthy ’ mitochondrial populations.The bioenergetics of the cell are likely regulated by energy requirements and substrate availability. Additionally,the overall quality of the mitochondrial population and the relative abundance of mitochondria in cells and tissues also impinge on overall bioenergetic capacity and resistance to stress. Because mitochondria are susceptible to damage mediated by reactive oxygen/nitrogen and lipid species, maintaining a ‘ healthy ’ population of mitochondria through quality control mechanisms appears to be essential for cell survival under conditions of pathological stress. Accumulating evidence suggest that mitophagy is particularly important for preventing amplification of initial oxidative insults, which otherwise would further impair the respiratory chain or promote mutations in mitochondrial DNA (mtDNA). The processes underlying the regulation of mitophagy depend on several factors, including the integrity of mtDNA, electron transport chain activity, and the interaction and regulation of the autophagic machinery. The integration and interpretation of cellular bioenergetics in the context of mitochondrial quality control and genetics is the theme of this review.
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Affiliation(s)
- Bradford G. Hill
- Diabetes and Obesity Center, Institute of Molecular Cardiology, and Department of Medicine, University of Louisville, Louisville, KY
- Departments of Biochemistry and Molecular Biology and Physiology and Biophysics, University of Louisville, Louisville, KY
| | - Gloria A. Benavides
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Jack R. Lancaster
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Scott Ballinger
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Medicine, Center for Heart Failure Research, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Lou Dell’Italia
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Medicine, Center for Heart Failure Research, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Veteran Affairs Medical Center, Birmingham, AL 35294
| | - Jianhua Zhang
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Veteran Affairs Medical Center, Birmingham, AL 35294
| | - Victor M. Darley-Usmar
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Medicine, Center for Heart Failure Research, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
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468
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Lauring AS, Lee TH, Martin JN, Hunt PW, Deeks SG, Busch M. Lack of evidence for mtDNA as a biomarker of innate immune activation in HIV infection. PLoS One 2012; 7:e50486. [PMID: 23209754 PMCID: PMC3510194 DOI: 10.1371/journal.pone.0050486] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 10/22/2012] [Indexed: 11/19/2022] Open
Abstract
Many human immunodeficiency virus (HIV) infected individuals suffer from persistent immune activation. Chronic inflammation and immune dysregulation have been associated with an increased risk of age-related diseases even among patients on highly active antiretroviral therapy. The factors leading to immune activation are complex, but have been hypothesized to include persistent viral replication with cellular death as well as microbial translocation across the gastrointestinal tract. Both processes may trigger innate immune responses since many native molecules released from dying cells are similar in structure to pathogen associated molecular patterns. These damage associated molecular patterns include mitochondrial DNA and formylated peptides. We hypothesized that circulating mitochondrial nucleic acid could serve as a biomarker for HIV-associated cell death and drive innate immune activation in infected individuals. We developed a quantitative polymerase chain reaction assay for plasma mitochondrial DNA and validated it on normal blood donors. We then measured mitochondrial DNA levels in acute and chronic HIV infection. While the assay proved to be accurate with a robust dynamic range, we did not find a significant association between HIV disease status and circulating mitochondrial DNA. We did, however, observe a negative correlation between age and plasma mitochondrial DNA levels in individuals with well-controlled HIV.
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Affiliation(s)
- Adam S. Lauring
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
- Blood Systems Research Institute, San Francisco, California, United States of America
- * E-mail:
| | - Tzong-Hae Lee
- Blood Systems Research Institute, San Francisco, California, United States of America
| | - Jeffrey N. Martin
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Peter W. Hunt
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Steven G. Deeks
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Michael Busch
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, California, United States of America
- Blood Systems Research Institute, San Francisco, California, United States of America
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469
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470
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Kubes P, Mehal WZ. Sterile inflammation in the liver. Gastroenterology 2012; 143:1158-1172. [PMID: 22982943 DOI: 10.1053/j.gastro.2012.09.008] [Citation(s) in RCA: 493] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 08/10/2012] [Accepted: 09/13/2012] [Indexed: 12/13/2022]
Abstract
Inflammation In the absence of pathogens occurs in all tissues in response to a wide range of stimuli that cause tissue stress and injury. Such sterile inflammation (SI) is a key process in drug-induced liver injury, nonalcoholic steatohepatitis, and alcoholic steatohepatitis and is a major determinant of fibrosis and carcinogenesis. In SI, endogenous damage-associated molecular patterns (DAMPS), which are usually hidden from the extracellular environment, are released on tissue injury and activate receptors on immune cells. More than 20 such DAMPS have been identified and activate cellular pattern recognition receptors, which were originally identified as sensors of pathogen-associated molecular patterns. Activation of pattern recognition receptors by DAMPS results in a wide range of immune responses, including production of proinflammatory cytokines and localization of immune cells to the site of injury. DAMPS result in the assembly of a cytosolic protein complex termed the inflammasome, which activates the serine protease caspase-1, resulting in activation and secretion of interleukin-1β and other cytokines. SI-driven liver diseases are responsible for the majority of liver pathology in industrially developed countries and lack specific therapy. Identification of DAMPS, their receptors, signaling pathways, and cytokines now provides a wide range of therapeutic targets for which many antagonists are already available.
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Affiliation(s)
- Paul Kubes
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Wajahat Z Mehal
- Section of Digestive Diseases, Yale University, and West Haven Veterans Medical Center, New Haven, Connecticut.
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471
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Salminen A, Ojala J, Kaarniranta K, Kauppinen A. Mitochondrial dysfunction and oxidative stress activate inflammasomes: impact on the aging process and age-related diseases. Cell Mol Life Sci 2012; 69:2999-3013. [PMID: 22446749 PMCID: PMC11114788 DOI: 10.1007/s00018-012-0962-0] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/23/2012] [Accepted: 03/12/2012] [Indexed: 12/20/2022]
Abstract
Oxidative stress and low-grade inflammation are the hallmarks of the aging process and are even more enhanced in many age-related degenerative diseases. Mitochondrial dysfunction and oxidative stress can provoke and potentiate inflammatory responses, but the mechanism has remained elusive. Recent studies indicate that oxidative stress can induce the assembly of multiprotein inflammatory complexes called the inflammasomes. Nod-like receptor protein 3 (NLRP3) is the major immune sensor for cellular stress signals, e.g., reactive oxygen species, ceramides, and cathepsin B. NLRP3 activation triggers the caspase-1-mediated maturation of the precursors of IL-1β and IL-18 cytokines. During aging, the autophagic clearance of mitochondria declines and dysfunctional mitochondria provoke chronic oxidative stress, which disturbs the cellular redox balance. Moreover, increased NF-κB signaling observed during aging could potentiate the expression of NLRP3 and cytokine proforms enhancing the priming of NLRP3 inflammasomes. Recent studies have demonstrated that NLRP3 activation is associated with several age-related diseases, e.g., the metabolic syndrome. We will review here the emerging field of inflammasomes in the appearance of the proinflammatory phenotype during the aging process and in age-related diseases.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211, Kuopio, Finland.
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472
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Vaamonde-García C, Riveiro-Naveira RR, Valcárcel-Ares MN, Hermida-Carballo L, Blanco FJ, López-Armada MJ. Mitochondrial dysfunction increases inflammatory responsiveness to cytokines in normal human chondrocytes. ACTA ACUST UNITED AC 2012; 64:2927-36. [DOI: 10.1002/art.34508] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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473
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Chapple ILC, Matthews JB, Wright HJ, Scott AE, Griffiths HR, Grant MM. Ascorbate and α-tocopherol differentially modulate reactive oxygen species generation by neutrophils in response to FcγR and TLR agonists. Innate Immun 2012; 19:152-9. [DOI: 10.1177/1753425912455207] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Periodontitis, a ubiquitous chronic inflammatory disease, is associated with reduced antioxidant defences and neutrophil hyperactivity in terms of reactive oxygen species (ROS) generation. Its phenotype is thus characterized by oxidative stress. We have determined the effect of antioxidant micronutrients ascorbate and α-tocopherol on neutrophil ROS generation. Peripheral neutrophils from periodontally-healthy individuals ( n = 20) were challenged with phorbol myristate acetate, IgG-opsonised Staphylococcus aureus, Fusobacterium nucleatum or PBS in the presence and absence of micronutrients (50 µM). Total and extracellular ROS were measured by luminol and isoluminol chemiluminescence respectively. Total and extracellular unstimulated, baseline ROS generation was unaffected by α-tocopherol, but inhibited by ascorbate and a combination of both micronutrients. Fcγ-receptor (Fcγ-R)-stimulated total or extracellular ROS generation was not affected by the presence of individual micronutrients. However, the combination significantly reduced extracellular FcγR-stimulated ROS release. Neither micronutrient inhibited TLR-stimulated total ROS, but the combination caused inhibition. Ascorbate and the micronutrient combination, but not α-tocopherol, inhibited extracellular ROS release by TLR-stimulated cells. Such micronutrient effects in vivo could be beneficial in reducing collateral tissue damage in chronic inflammatory diseases, such as periodontitis, while retaining immune-mediated neutrophil function.
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Affiliation(s)
- Iain LC Chapple
- School of Dentistry and MRC Centre for Immune Regulation, University of Birmingham, St Chads Queensway, Birmingham, UK
| | - John B Matthews
- School of Dentistry and MRC Centre for Immune Regulation, University of Birmingham, St Chads Queensway, Birmingham, UK
| | - Helen J Wright
- School of Dentistry and MRC Centre for Immune Regulation, University of Birmingham, St Chads Queensway, Birmingham, UK
| | - Ann E Scott
- Unilever Oral Care UK, Port Sunlight, Quarry Road East, Bebington, UK
| | | | - Melissa M Grant
- School of Dentistry and MRC Centre for Immune Regulation, University of Birmingham, St Chads Queensway, Birmingham, UK
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474
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Salminen A, Kaarniranta K, Kauppinen A. Inflammaging: disturbed interplay between autophagy and inflammasomes. Aging (Albany NY) 2012; 4:166-75. [PMID: 22411934 PMCID: PMC3348477 DOI: 10.18632/aging.100444] [Citation(s) in RCA: 323] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Inflammaging refers to a low-grade pro-inflammatory phenotype which accompanies aging in mammals. The aging process is associated with a decline in autophagic capacity which impairs cellular housekeeping, leading to protein aggregation and accumulation of dysfunctional mitochondria which provoke reactive oxygen species (ROS) production and oxidative stress. Recent studies have clearly indicated that the ROS production induced by damaged mitochondria can stimulate intracellular danger-sensing multiprotein platforms called inflammasomes. Nod-like receptor 3 (NLRP3) can be activated by many danger signals, e.g. ROS, cathepsin B released from destabilized lysosomes and aggregated proteins, all of which evoke cellular stress and are involved in the aging process. NLRP3 activation is also enhanced in many age-related diseases, e.g. atherosclerosis, obesity and type 2 diabetes. NLRP3 activates inflammatory caspases, mostly caspase-1, which cleave the inactive precursors of IL-1β and IL-18 and stimulate their secretion. Consequently, these cytokines provoke inflammatory responses and accelerate the aging process by inhibiting autophagy. In conclusion, inhibition of autophagic capacity with aging generates the inflammaging condition via the activation of inflammasomes, in particular NLRP3. We will provide here a perspective on the current research of the ROS-dependent activation of inflammasomes triggered by the decline in autophagic cleansing of dysfunctional mitochondria.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
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475
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Russell SE, Walsh PT. Sterile inflammation - do innate lymphoid cell subsets play a role? Front Immunol 2012; 3:246. [PMID: 22891068 PMCID: PMC3413015 DOI: 10.3389/fimmu.2012.00246] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 07/24/2012] [Indexed: 01/13/2023] Open
Abstract
The recent identification of several novel innate lymphoid cell (iLC) subsets has increased our understanding of the mechanisms which link the innate and adaptive immune systems. While the contribution of these subsets toward the pathogenesis of human disease remains largely to be determined, it seems likely that they will play a particularly important role in sterile inflammatory settings where the innate response is seen as a critical mediator of inflammation. Several recent studies have highlighted the role of endogenous damage-associated molecular patterns such as IL-33, IL-1α, and IL-1β in promoting lymphoid cell responses. This review discusses the influence of such endogenous danger signals on novel iLCs such as lymphoid tissue-inducer cells, innate type 2 helper cells, and γδ T cells and explores how these responses may contribute to the development of an inflammatory response in a sterile setting.
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Affiliation(s)
- Shane E Russell
- Department of Clinical Medicine, School of Medicine, Trinity College Dublin, Dublin, Ireland
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476
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Zorov DB, Plotnikov EY, Jankauskas SS, Isaev NK, Silachev DN, Zorova LD, Pevzner IB, Pulkova NV, Zorov SD, Morosanova MA. The phenoptosis problem: What is causing the death of an organism? Lessons from acute kidney injury. BIOCHEMISTRY (MOSCOW) 2012; 77:742-53. [DOI: 10.1134/s0006297912070073] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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477
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Pugin J. How tissue injury alarms the immune system and causes a systemic inflammatory response syndrome. Ann Intensive Care 2012; 2:27. [PMID: 22788849 PMCID: PMC3488542 DOI: 10.1186/2110-5820-2-27] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 04/15/2012] [Indexed: 01/26/2023] Open
Abstract
Systemic inflammation is very prevalent among critically ill patients, particularly those with extensive tissue injury. Although downstream mediators (cytokines) and effector cells (phagocytes) have been identified, proximal mediators originating from injured tissues remained elusive. Alarmins (“danger signals”) released by necrotic/injured cells have been identified recently and certainly play a role in triggering local and systemic inflammation in critically ill patients. The most promising alarmin candidates are of mitochondrial origin, i.e. mitochondrial DNA and the chemotactic factor fMet-Leu-Phe (fMLP). ATP also is released from necrotic tissues and stimulates the assembly of the inflammasome, leading to the production of proinflammatory cytokines, such as interleukin (IL)-1ß. The identification of novel alarmins opens new therapeutic avenues for the treatment of severe SIRS, and SIRS-dependent organ dysfunction.
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Affiliation(s)
- Jérôme Pugin
- Intensive Care - SIRS Unit, University Hospitals of Geneva, 1211, Geneva 14, Switzerland.
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478
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Acute phase proteins in ruminants. J Proteomics 2012; 75:4207-31. [DOI: 10.1016/j.jprot.2012.04.004] [Citation(s) in RCA: 307] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/29/2012] [Accepted: 04/02/2012] [Indexed: 01/03/2023]
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479
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Kool M, Fierens K, Lambrecht BN. Alum adjuvant: some of the tricks of the oldest adjuvant. J Med Microbiol 2012; 61:927-934. [DOI: 10.1099/jmm.0.038943-0] [Citation(s) in RCA: 201] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Mirjam Kool
- Department of Pulmonary Medicine, Erasmus MC, Rotterdam, The Netherlands
- Laboratory of Immunoregulation and Mucosal Immunology, University Hospital Ghent, Ghent, Belgium
| | - Kaat Fierens
- Laboratory of Immunoregulation and Mucosal Immunology, University Hospital Ghent, Ghent, Belgium
| | - Bart N. Lambrecht
- Department of Pulmonary Medicine, Erasmus MC, Rotterdam, The Netherlands
- Laboratory of Immunoregulation and Mucosal Immunology, University Hospital Ghent, Ghent, Belgium
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480
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ATP release from dying autophagic cells and their phagocytosis are crucial for inflammasome activation in macrophages. PLoS One 2012; 7:e40069. [PMID: 22768222 PMCID: PMC3386917 DOI: 10.1371/journal.pone.0040069] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 05/31/2012] [Indexed: 12/22/2022] Open
Abstract
Pathogen-activated and damage-associated molecular patterns activate the inflammasome in macrophages. We report that mouse macrophages release IL-1β while co-incubated with pro-B (Ba/F3) cells dying, as a result of IL-3 withdrawal, by apoptosis with autophagy, but not when they are co-incubated with living, apoptotic, necrotic or necrostatin-1 treated cells. NALP3-deficient macrophages display reduced IL-1β secretion, which is also inhibited in macrophages deficient in caspase-1 or pre-treated with its inhibitor. This finding demonstrates that the inflammasome is activated during phagocytosis of dying autophagic cells. We show that activation of NALP3 depends on phagocytosis of dying cells, ATP release through pannexin-1 channels of dying autophagic cells, P2X7 purinergic receptor activation, and on consequent potassium efflux. Dying autophagic Ba/F3 cells injected intraperitoneally in mice recruit neutrophils and thereby induce acute inflammation. These findings demonstrate that NALP3 performs key upstream functions in inflammasome activation in mouse macrophages engulfing dying autophagic cells, and that these functions lead to pro-inflammatory responses.
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481
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Uzhachenko R, Issaeva N, Boyd K, Ivanov SV, Carbone DP, Ivanova AV. Tumour suppressor Fus1 provides a molecular link between inflammatory response and mitochondrial homeostasis. J Pathol 2012; 227:456-69. [PMID: 22513871 DOI: 10.1002/path.4039] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 04/04/2012] [Accepted: 04/07/2012] [Indexed: 02/04/2023]
Abstract
Fus1, encoded by a 3p21.3 tumour suppressor gene, is down-regulated, mutated or lost in the majority of inflammatory thoracic malignancies. The mitochondrial localization of Fus1 stimulated us to investigate how Fus1 modulates inflammatory response and mitochondrial function in a mouse model of asbestos-induced peritoneal inflammation. Asbestos treatment resulted in a decreased Fus1 expression in wild-type (WT) peritoneal immune cells, suggesting that asbestos exposure may compromise the Fus1-mediated inflammatory response. Untreated Fus1(-/-) mice had an ~eight-fold higher proportion of peritoneal granulocytes than Fus1(+/+) mice, pointing at ongoing chronic inflammation. Fus1(-/-) mice exhibited a perturbed inflammatory response to asbestos, reflected in decreased immune organ weight and peritoneal fluid protein concentration, along with an increased proportion of peritoneal macrophages. Fus1(-/-) immune cells showed augmented asbestos-induced activation of key inflammatory, anti-oxidant and genotoxic stress response proteins ERK1/2, NFκB, SOD2, γH2AX, etc. Moreover, Fus1(-/-) mice demonstrated altered dynamics of pro- and anti-inflammatory cytokine expression, such as IFNγ, TNFα, IL-1A, IL-1B and IL-10. 'Late' response cytokine Ccl5 was persistently under-expressed in Fus1(-/-) immune cells at both basal and asbestos-activated states. We observed an asbestos-related difference in the size of CD3(+) CD4(-) CD8(-) DN T cell subset that was expanded four-fold in Fus1(-/-) mice. Finally, we demonstrated Fus1-dependent basal and asbestos-induced changes in major mitochondrial parameters (ROS production, mitochondrial potential and UCP2 expression) in Fus1(-/-) immune cells and in Fus1-depleted cancer cells, thus supporting our hypothesis that Fus1 establishes its immune- and tumour-suppressive activities via regulation of mitochondrial homeostasis.
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Affiliation(s)
- Roman Uzhachenko
- Department of Medicine, Division of Hematology/Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
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482
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Denk S, Perl M, Huber-Lang M. Damage- and Pathogen-Associated Molecular Patterns and Alarmins: Keys to Sepsis? Eur Surg Res 2012; 48:171-9. [DOI: 10.1159/000338194] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 03/16/2012] [Indexed: 12/19/2022]
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483
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David S, Greenhalgh AD, López-Vales R. Role of phospholipase A2s and lipid mediators in secondary damage after spinal cord injury. Cell Tissue Res 2012; 349:249-67. [PMID: 22581384 DOI: 10.1007/s00441-012-1430-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/05/2012] [Indexed: 11/26/2022]
Abstract
Inflammation is considered to be an important contributor to secondary damage after spinal cord injury (SCI). This secondary damage leads to further exacerbation of tissue loss and functional impairments. The immune responses that are triggered by injury are complex and are mediated by a variety of factors that have both detrimental and beneficial effects. In this review, we focus on the diverse effects of the phospholipase A(2) (PLA(2)) superfamily and the downstream pathways that generate a large number of bioactive lipid mediators, some of which have pro-inflammatory and demyelinating effects, whereas others have anti-inflammatory and pro-resolution properties. For each of these lipid mediators, we provide an overview followed by a discussion of their expression and role in SCI. Where appropriate, we have compared the latter with their role in other neurological conditions. The PLA(2) pathway provides a number of targets for therapeutic intervention for the treatment of SCI and other neurological conditions.
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Affiliation(s)
- Samuel David
- Center for Research in Neuroscience, The Research Institute of the McGill University Health Center, Livingston Hall, Room L7-210, 1650 Cedar Ave., Montreal, Quebec, Canada, H3G 1A4,
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484
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Manson J, Thiemermann C, Brohi K. Trauma alarmins as activators of damage-induced inflammation. Br J Surg 2012; 99 Suppl 1:12-20. [PMID: 22441851 DOI: 10.1002/bjs.7717] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND A systemic inflammatory response syndrome (SIRS) is frequently observed after traumatic injury. The response is sterile and the activating stimulus is tissue damage. Endogenous molecules, called alarmins, are reputed to be released by injured tissues but the precise identity of these mediators is unclear. This review summarizes current preclinical and clinical evidence for trauma alarmins and their role in innate immune activation. METHODS A comprehensive literature review of putative alarmins in tissue damage after traumatic injury was conducted. RESULTS The presence of SIRS at admission is an independent predictor of mortality after trauma. The primary initiators of the human immune response are unclear. Several endogenous substances display alarmin characteristics in vitro. Preclinical studies demonstrate that blockade of certain endogenous substances can reduce adverse clinical sequelae after traumatic injury. Human evidence for trauma alarmins is extremely limited. CONCLUSION The magnitude of acute inflammation is predictive of outcome after trauma, suggesting that an early opportunity for immune modulation may exist. An understanding of the mechanisms of innate immune activation following trauma may lead to new therapeutic agents and improved patient survival.
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Affiliation(s)
- J Manson
- Trauma Sciences, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London E1 2AT, UK.
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485
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Abstract
Immunity is based on self/nonself discrimination. In vertebrates, two major systems, innate and adaptive immune systems, constitute host defense against invading microbes. Adaptive immunity is characterized by specific immune responses through B- or T-cell antigen receptors that are generated by somatic recombination, whereas nonspecific responses to microbes had been accentuated in innate immunity. However, the discovery of pattern recognition receptors (PRRs) that are encoded in the germ-line, including Toll-like receptors, RIG-I-like receptors, NOD-like receptors and AIM2-like receptors, advanced our understanding of a mechanism for innate immune recognition. These types of PRR recognize pathogen- or damage-associated molecular patterns (PAMPs or DAMPs) during infection or tissue damage, and commonly evoke the downstream gene induction programme, such as expression of type I interferons, inflammatory cytokines and chemokines. Dysregulation of PRR-triggered signal activation leads to pathologic inflammatory responses. In this regard, it has been shown that many of "autoinflammatory diseases", recently defined clinical entity, have putatively causative mutations in the genes that encode PRRs or their signaling mediators. In this review article, we describe recent overview of PRRs as innate sensors and update knowledge of "autoinflammatory diseases" particularly by focusing on their association with innate signaling.
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Affiliation(s)
- Takaya Hayashi
- Research Center of Infection-Associated Cancer, Hokkaido University, Sapporo, Japan
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486
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RIP kinase-dependent necrosis drives lethal systemic inflammatory response syndrome. Immunity 2012; 35:908-18. [PMID: 22195746 DOI: 10.1016/j.immuni.2011.09.020] [Citation(s) in RCA: 529] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 09/07/2011] [Accepted: 09/18/2011] [Indexed: 11/20/2022]
Abstract
Engagement of tumor necrosis factor receptor 1 signals two diametrically opposed pathways: survival-inflammation and cell death. An additional switch decides, depending on the cellular context, between caspase-dependent apoptosis and RIP kinase (RIPK)-mediated necrosis, also termed necroptosis. We explored the contribution of both cell death pathways in TNF-induced systemic inflammatory response syndrome (SIRS). Deletion of apoptotic executioner caspases (caspase-3 or -7) or inflammatory caspase-1 had no impact on lethal SIRS. However, deletion of RIPK3 conferred complete protection against lethal SIRS and reduced the amounts of circulating damage-associated molecular patterns. Pretreatment with the RIPK1 kinase inhibitor, necrostatin-1, provided a similar effect. These results suggest that RIPK1-RIPK3-mediated cellular damage by necrosis drives mortality during TNF-induced SIRS. RIPK3 deficiency also protected against cecal ligation and puncture, underscoring the clinical relevance of RIPK kinase inhibition in sepsis and identifying components of the necroptotic pathway that are potential therapeutic targets for treatment of SIRS and sepsis.
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487
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Zornetta I, Caccin P, Fernandez J, Lomonte B, Gutierrez JM, Montecucco C. Envenomations by Bothrops and Crotalus snakes induce the release of mitochondrial alarmins. PLoS Negl Trop Dis 2012; 6:e1526. [PMID: 22363828 PMCID: PMC3283552 DOI: 10.1371/journal.pntd.0001526] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/23/2011] [Indexed: 12/20/2022] Open
Abstract
Skeletal muscle necrosis is a common manifestation of viperid snakebite envenomations. Venoms from snakes of the genus Bothrops, such as that of B. asper, induce muscle tissue damage at the site of venom injection, provoking severe local pathology which often results in permanent sequelae. In contrast, the venom of the South American rattlesnake Crotalus durissus terrificus, induces a clinical picture of systemic myotoxicity, i.e., rhabdomyolysis, together with neurotoxicity. It is known that molecules released from damaged muscle might act as ‘danger’ signals. These are known as ‘alarmins’, and contribute to the inflammatory reaction by activating the innate immune system. Here we show that the venoms of B. asper and C. d. terrificus release the mitochondrial markers mtDNA (from the matrix) and cytochrome c (Cyt c) from the intermembrane space, from ex vivo mouse tibialis anterior muscles. Cyt c was released to a similar extent by the two venoms whereas B. asper venom induced the release of higher amounts of mtDNA, thus reflecting hitherto some differences in their pathological action on muscle mitochondria. At variance, injection of these venoms in mice resulted in a different time-course of mtDNA release, with B. asper venom inducing an early onset increment in plasma levels and C. d. terrificus venom provoking a delayed release. We suggest that the release of mitochondrial ‘alarmins’ might contribute to the local and systemic inflammatory events characteristic of snakebite envenomations. Every year, hundreds of thousands of people in tropical and sub-tropical areas of the world are bitten by poisonous snakes and may develop permanent damages. This is a major tropical disease which is largely neglected by scientific and clinical investigators. Snakes of Bothrops and Crotalus genus are responsible of most cases in Latin America. Here for the first time, we have shown that these venoms cause the release of both mitochondrial DNA and cytochrome c, two well known alarmins. Moreover, the kinetic of these processes are in agreement with the different pathophysiological profiles exhibited by Bothrops and Crotalus envenomations. These elements suggest a correlation between snake evenomations and sterile inflammatory syndrome. Alarmins are reported to have a fundamental role in innate immune response and inflammation; they might contribute to the local and systemic inflammatory events characteristic of these envenomations opening a new prospective in the study of these complex pathologies.
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Affiliation(s)
- Irene Zornetta
- Dipartimento di Scienze Biomediche, Università degli Studi di Padova, Padova, Italy
| | - Paola Caccin
- Dipartimento di Scienze Biomediche, Università degli Studi di Padova, Padova, Italy
| | - Julián Fernandez
- Dipartimento di Scienze Biomediche, Università degli Studi di Padova, Padova, Italy
| | - Bruno Lomonte
- Facultad de Microbiología, Instituto Clodomiro Picado, Universidad de Costa Rica, San José, Costa Rica
| | - José María Gutierrez
- Facultad de Microbiología, Instituto Clodomiro Picado, Universidad de Costa Rica, San José, Costa Rica
| | - Cesare Montecucco
- Dipartimento di Scienze Biomediche, Università degli Studi di Padova, Padova, Italy
- * E-mail:
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488
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Vandenesch F, Lina G, Henry T. Staphylococcus aureus hemolysins, bi-component leukocidins, and cytolytic peptides: a redundant arsenal of membrane-damaging virulence factors? Front Cell Infect Microbiol 2012; 2:12. [PMID: 22919604 PMCID: PMC3417661 DOI: 10.3389/fcimb.2012.00012] [Citation(s) in RCA: 233] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Accepted: 01/31/2012] [Indexed: 12/17/2022] Open
Abstract
One key aspect of the virulence of Staphylococcus aureus lies in its ability to target the host cell membrane with a large number of membrane-damaging toxins and peptides. In this review, we describe the hemolysins, the bi-component leukocidins (which include the Panton Valentine leukocidin, LukAB/GH, and LukED), and the cytolytic peptides (phenol soluble modulins). While at first glance, all of these factors might appear redundant, it is now clear that some of these factors play specific roles in certain S. aureus life stages and diseases or target specific cell types or species. In this review, we present an update of the literature on toxin receptors and their cell type and species specificities. Furthermore, we review epidemiological studies and animal models illustrating the role of these membrane-damaging factors in various diseases. Finally, we emphasize the interplay of these factors with the host immune system and highlight all their non-lytic functions.
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Affiliation(s)
- François Vandenesch
- Bacterial Pathogenesis and Innate Immunity Laboratory, INSERM U851 "Immunity, Infection and Vaccination," Lyon, France
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489
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Borges AM, Healey GD, Sheldon IM. Explants of intact endometrium to model bovine innate immunity and inflammation ex vivo. Am J Reprod Immunol 2012; 67:526-39. [PMID: 22324889 DOI: 10.1111/j.1600-0897.2012.01106.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/15/2012] [Indexed: 12/28/2022] Open
Abstract
PROBLEM Bacterial infections commonly cause bovine endometritis and infertility via innate immune pathways. However, mechanistic studies using isolated cells or chopped tissue may be compromised by the disruption of endometrial architecture and release of damage-associated molecular patterns. So, this study aimed to establish an ex vivo model of intact bovine endometrium to study innate immunity and inflammation. METHOD OF STUDY Intact bovine endometrium explants were collected using a sterile 8-mm punch biopsy and cultured ex vivo with bacteria or pathogen-associated molecules. Interleukin accumulation was measured, and tissue viability was assessed by microscopy, TdT-mediated biotin-dUTP nick-end labelling and lactate dehydrogenase assay. RESULTS Intact endometrium explants accumulated IL-6, IL-1β and IL-8 in response to Gram-negative or Gram-positive bacteria, and their purified pathogen-associated molecules; inflammatory responses were dependent on the stage of oestrous cycle. Explants of intact endometrium maintained viability and tissue architecture, and had lower basal accumulation of interleukins compared with explants using chopped endometrium. CONCLUSION This study established a tractable ex vivo model of intact endometrium to explore the mechanisms of immunity and inflammation in the bovine endometrium.
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Affiliation(s)
- Alan Maia Borges
- College of Medicine, Institute of Life Science, Swansea University, UK
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490
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Garg AD, Krysko DV, Vandenabeele P, Agostinis P. Hypericin-based photodynamic therapy induces surface exposure of damage-associated molecular patterns like HSP70 and calreticulin. Cancer Immunol Immunother 2012; 61:215-221. [PMID: 22193987 PMCID: PMC11029694 DOI: 10.1007/s00262-011-1184-2] [Citation(s) in RCA: 223] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 12/04/2011] [Indexed: 12/29/2022]
Abstract
Surface-exposed HSP70 and calreticulin are damage-associated molecular patterns (DAMPs) crucially involved in modulating the success of cancer therapy. Photodynamic therapy (PDT) involves the administration of a photosensitising (PTS) agent followed by visible light-irradiation. The reactive oxygen species that are thus generated directly kill tumours by damaging their microvasculature and inducing a local inflammatory reaction. PDT with the PTS photofrin is associated with DAMPs exposure, but the same is not true for other PTSs. Here, we show that when cancer cells are treated with hypericin-based PDT (Hyp-PDT), they surface-expose both HSP70 and calreticulin (CRT). Induction of CRT exposure was not accompanied by co-exposure of ERp57, but this did not compromise the ability of the exposed CRT to regulate the phagocytosis of Hyp-PDT-treated cancer cells by dendritic cells. Interestingly, we found that Hyp-PDT-induced CRT exposure (in contrast to anthracycline-induced CRT exposure) was independent of the presence of ERp57. Our results indicate that Hyp-PDT is a potential anti-cancer immunogenic modality.
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Affiliation(s)
- Abhishek D Garg
- Cell Death Research and Therapy Unit, Department of Molecular Cell Biology, Faculty of Medicine, Catholic University of Leuven, Campus Gasthuisberg O&N1, Herestraat 49, 3000, Leuven, Belgium
| | - Dmitri V Krysko
- Molecular Signaling and Cell Death Unit, Department for Molecular Biomedical Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Peter Vandenabeele
- Molecular Signaling and Cell Death Unit, Department for Molecular Biomedical Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Patrizia Agostinis
- Cell Death Research and Therapy Unit, Department of Molecular Cell Biology, Faculty of Medicine, Catholic University of Leuven, Campus Gasthuisberg O&N1, Herestraat 49, 3000, Leuven, Belgium.
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491
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Tsuda H, Ning Z, Yamaguchi Y, Suzuki N. Programmed cell death and its possible relationship with periodontal disease. J Oral Sci 2012; 54:137-49. [DOI: 10.2334/josnusd.54.137] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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492
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Mitochondria: commanders of innate immunity and disease? Curr Opin Immunol 2011; 24:32-40. [PMID: 22138315 DOI: 10.1016/j.coi.2011.11.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 10/27/2011] [Accepted: 11/08/2011] [Indexed: 12/13/2022]
Abstract
Mitochondrial dysfunction is associated with the manifestation and origin of a plethora of diseases and disorders. Whilst classically the role of these archetypical 'powerhouses' in many disease phenotypes has been attributed to their ability to regulate cell metabolism and cell death pathways, emerging data posit that mitochondria may also act as powerful initiators and masters of the innate immune response. This new paradigm complements the current mitochondrial dogma, whereby molecules endogenously present on or inside the mitochondria may act as immune regulators in response to stress or pathogens and may also be responsible for the initiation and/or manifestation of chronic inflammation observed in many diseases and disorders.
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493
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Wang LF, Walker PJ, Poon LLM. Mass extinctions, biodiversity and mitochondrial function: are bats 'special' as reservoirs for emerging viruses? Curr Opin Virol 2011; 1:649-57. [PMID: 22440923 PMCID: PMC7102786 DOI: 10.1016/j.coviro.2011.10.013] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 10/16/2011] [Accepted: 10/17/2011] [Indexed: 01/11/2023]
Abstract
For the past 10-15 years, bats have attracted growing attention as reservoirs of emerging zoonotic viruses. This has been due to a combination of factors including the emergence of highly virulent zoonotic pathogens, such as Hendra, Nipah, SARS and Ebola viruses, and the high rate of detection of a large number of previously unknown viral sequences in bat specimens. As bats have ancient evolutionary origins and are the only flying mammals, it has been hypothesized that some of their unique biological features may have made them especially suitable hosts for different viruses. So the question 'Are bats different, special or exceptional?' has become a focal point in the field of virology, bat biology and virus-host co-evolution. In this brief review, we examine the topic in a relatively unconventional way, that is, our discussion will be based on both scientific discoveries and theoretical predictions. This approach was chosen partially because the data in this field are so limited that it is impossible to conduct a useful review based on published results only and also because we believe it is important to provoke original, speculative or even controversial ideas or theories in this important field of research.
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Affiliation(s)
- Lin-Fa Wang
- CSRIO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3216, Australia.
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494
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Kozlov AV, Bahrami S, Calzia E, Dungel P, Gille L, Kuznetsov AV, Troppmair J. Mitochondrial dysfunction and biogenesis: do ICU patients die from mitochondrial failure? Ann Intensive Care 2011; 1:41. [PMID: 21942988 PMCID: PMC3224479 DOI: 10.1186/2110-5820-1-41] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 09/26/2011] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial functions include production of energy, activation of programmed cell death, and a number of cell specific tasks, e.g., cell signaling, control of Ca2+ metabolism, and synthesis of a number of important biomolecules. As proper mitochondrial function is critical for normal performance and survival of cells, mitochondrial dysfunction often leads to pathological conditions resulting in various human diseases. Recently mitochondrial dysfunction has been linked to multiple organ failure (MOF) often leading to the death of critical care patients. However, there are two main reasons why this insight did not generate an adequate resonance in clinical settings. First, most data regarding mitochondrial dysfunction in organs susceptible to failure in critical care diseases (liver, kidney, heart, lung, intestine, brain) were collected using animal models. Second, there is no clear therapeutic strategy how acquired mitochondrial dysfunction can be improved. Only the benefit of such therapies will confirm the critical role of mitochondrial dysfunction in clinical settings. Here we summarized data on mitochondrial dysfunction obtained in diverse experimental systems, which are related to conditions seen in intensive care unit (ICU) patients. Particular attention is given to mechanisms that cause cell death and organ dysfunction and to prospective therapeutic strategies, directed to recover mitochondrial function. Collectively the data discussed in this review suggest that appropriate diagnosis and specific treatment of mitochondrial dysfunction in ICU patients may significantly improve the clinical outcome.
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Affiliation(s)
- Andrey V Kozlov
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, A-1200 Vienna, Austria.
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495
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Cossarizza A, Pinti M, Nasi M, Gibellini L, Manzini S, Roat E, De Biasi S, Bertoncelli L, Montagna JP, Bisi L, Manzini L, Trenti T, Borghi V, Mussini C. Increased plasma levels of extracellular mitochondrial DNA during HIV infection: a new role for mitochondrial damage-associated molecular patterns during inflammation. Mitochondrion 2011; 11:750-5. [PMID: 21722755 DOI: 10.1016/j.mito.2011.06.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 05/02/2011] [Accepted: 06/15/2011] [Indexed: 12/13/2022]
Abstract
HIV infection is characterized by a chronic inflammatory state. Recently, it has been shown that mitochondrial DNA (mtDNA) released from damaged or dead cells can bind Toll like receptor-9 (TLR9), an intracellular receptor that responds to bacterial or viral DNA molecules. The activation of TLR9 present within monocytes or neutrophils results in a potent inflammatory reaction, with the production of proinflammatory cytokines. We measured plasma levels of mtDNA in different groups of HIV(+) patients, i.e., those experiencing an acute HIV infection (AHI), long term non progressors (LTNP), late presenters (LP) taking antiretroviral therapy for the first time, and healthy controls. We found that in AHI and LP mtDNA plasma levels were significantly higher than in healthy individuals or in LTNP. Plasma mtDNA levels were not correlated to peripheral blood CD4(+) T cell count, nor to markers of immune activation, but had a significant correlation with plasma viral load, revealing a possible role for mtDNA in inflammation, or as a biomarker of virus-induced damage.
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Affiliation(s)
- Andrea Cossarizza
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, via Campi 287, 41125 Modena, Italy.
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