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Hopp MT, Holze J, Lauber F, Holtkamp L, Rathod DC, Miteva MA, Prestes EB, Geyer M, Manoury B, Merle NS, Roumenina LT, Bozza MT, Weindl G, Imhof D. Insights into the molecular basis and mechanism of heme-triggered TLR4 signalling: The role of heme-binding motifs in TLR4 and MD2. Immunology 2024; 171:181-197. [PMID: 37885279 DOI: 10.1111/imm.13708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 10/06/2023] [Indexed: 10/28/2023] Open
Abstract
Haemolytic disorders, such as sickle cell disease, are accompanied by the release of high amounts of labile heme into the intravascular compartment resulting in the induction of proinflammatory and prothrombotic complications in affected patients. In addition to the relevance of heme-regulated proteins from the complement and blood coagulation systems, activation of the TLR4 signalling pathway by heme was ascribed a crucial role in the progression of these pathological processes. Heme binding to the TLR4-MD2 complex has been proposed recently, however, essential mechanistic information of the processes at the molecular level, such as heme-binding kinetics, the heme-binding capacity and the respective heme-binding sites (HBMs) is still missing. We report the interaction of TLR4, MD2 and the TLR4-MD2 complex with heme and the consequences thereof by employing biochemical, spectroscopic, bioinformatic and physiologically relevant approaches. Heme binding occurs transiently through interaction with up to four HBMs in TLR4, two HBMs in MD2 and at least four HBMs in their complex. Functional studies highlight that mutations of individual HBMs in TLR4 preserve full receptor activation by heme, suggesting that heme interacts with TLR4 through different binding sites independently of MD2. Furthermore, we confirm and extend the major role of TLR4 for heme-mediated cytokine responses in human immune cells.
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Affiliation(s)
- Marie-T Hopp
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, Bonn, Germany
- Department of Chemistry, Institute of Integrated Natural Sciences, University of Koblenz, Koblenz, Germany
| | - Janine Holze
- Pharmacology and Toxicology, Pharmaceutical Institute, University of Bonn, Bonn, Germany
| | - Felicitas Lauber
- Pharmacology and Toxicology, Pharmaceutical Institute, University of Bonn, Bonn, Germany
| | - Laura Holtkamp
- Pharmacology and Toxicology, Pharmaceutical Institute, University of Bonn, Bonn, Germany
| | - Dhruv C Rathod
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, Bonn, Germany
| | - Maria A Miteva
- CNRS UMR 8038 CiTCoM, Université de Paris, Faculté de Pharmacie de Paris, Paris, France
- INSERM U 1268 Medicinal Chemistry and Translational Research, Paris, France
| | - Elisa B Prestes
- Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, Bonn, Germany
| | - Bénédicte Manoury
- Institut Necker Enfants Malades, INSERM U1151-CNRS UMR8253, Université Paris Cité, Faculté de médecine Necker, Paris, France
| | - Nicolas S Merle
- Centre de Recherche des Cordeliers, UMR_S 1138, INSERM, Paris, France
- Centre de Recherche des Cordeliers, Sorbonne Universités, Paris, France
- Centre de Recherche des Cordeliers, Université Paris Descartes, Paris, France
| | - Lubka T Roumenina
- Centre de Recherche des Cordeliers, UMR_S 1138, INSERM, Paris, France
- Centre de Recherche des Cordeliers, Sorbonne Universités, Paris, France
- Centre de Recherche des Cordeliers, Université Paris Descartes, Paris, France
| | - Marcelo T Bozza
- Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Günther Weindl
- Pharmacology and Toxicology, Pharmaceutical Institute, University of Bonn, Bonn, Germany
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, Bonn, Germany
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Guo Y, Zhao H, Lin Z, Ye T, Xu D, Zeng Q. Heme in Cardiovascular Diseases: A Ubiquitous Dangerous Molecule Worthy of Vigilance. Front Cell Dev Biol 2022; 9:781839. [PMID: 35127704 PMCID: PMC8807526 DOI: 10.3389/fcell.2021.781839] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/13/2021] [Indexed: 12/20/2022] Open
Abstract
Heme, the protoporphyrin IX iron complex is widely present in the human body and it is involved in oxygen storage, electron transfer, and enzymatic reactions. However, free heme can be toxic as it catalyzes the production of reactive oxygen species, oxidizes lipids and proteins, and causes DNA damage, thereby inducing a pro-inflammatory environment. The generation, metabolism, and degradation of heme in the human body are regulated by precise mechanisms to ensure that heme remains non-toxic. However, in several types of cardiovascular diseases, impaired metabolism and exposure to heme may occur in pathological processes, including neovascularization, internal hemorrhage, ischemia, and reperfusion. Based on years of research, in this review, we aimed to summarize the underlying mechanisms by which heme contributes to the development of cardiovascular diseases through oxidative stress, relative pathway gene expression regulation and phenotypic changes in cells. Excess heme plays a detrimental role in atherosclerosis, heart failure, myocardial ischemia-reperfusion injury, degenerative aortic valve stenosis, cardiac iron overload. Recent researches revealed that in some cases heme involved in cardiac damage though ferroptosis. Thus, heme concentrations beyond normal levels are dangerous. Further research on the role of heme in cardiovascular diseases is needed.
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Affiliation(s)
- Yuyang Guo
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Shock and Microcirculation, Southern Medical University, Guangzhou, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Hengli Zhao
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Shock and Microcirculation, Southern Medical University, Guangzhou, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Zhibin Lin
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Shock and Microcirculation, Southern Medical University, Guangzhou, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Taochun Ye
- Department of Cardiopulmonary Rehabilitation, First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Dingli Xu
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Shock and Microcirculation, Southern Medical University, Guangzhou, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
- *Correspondence: Qingchun Zeng, ; Dingli Xu,
| | - Qingchun Zeng
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Shock and Microcirculation, Southern Medical University, Guangzhou, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
- *Correspondence: Qingchun Zeng, ; Dingli Xu,
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Abstract
Sickle cell disease (SCD) is a genetic disease caused by a single mutation in the β-globin gene, leading to the production of an abnormal hemoglobin called hemoglobin S (HbS), which polymerizes under deoxygenation, and induces the sickling of red blood cells (RBCs). Sickled RBCs are very fragile and rigid, and patients consequently become anemic and develop frequent and recurrent vaso-occlusive crises. However, it is now evident that SCD is not only a RBC rheological disease. Accumulating evidence shows that SCD is also characterized by the presence of chronic inflammation and oxidative stress, participating in the development of chronic vasculopathy and several chronic complications. The accumulation of hemoglobin and heme in the plasma, as a consequence of enhanced intravascular hemolysis, decreases nitric oxide bioavailability and enhances the production of reactive oxygen species (ROS). Heme and hemoglobin also represent erythrocytic danger-associated molecular pattern molecules (eDAMPs), which may activate endothelial inflammation through TLR-4 signaling and promote the development of complications, such as acute chest syndrome. It is also suspected that heme may activate the innate immune complement system and stimulate neutrophils to release neutrophil extracellular traps. A large amount of microparticles (MPs) from various cellular origins (platelets, RBCs, white blood cells, endothelial cells) is also released into the plasma of SCD patients and participate in the inflammation and oxidative stress in SCD. In turn, this pro-inflammatory and oxidative stress environment further alters the RBC properties. Increased pro-inflammatory cytokine concentrations promote the activation of RBC NADPH oxidase and, thus, raise the production of intra-erythrocyte ROS. Such enhanced oxidative stress causes deleterious damage to the RBC membrane and further alters the deformability of the cells, modifying their aggregation properties. These RBC rheological alterations have been shown to be associated to specific SCD complications, such as leg ulcers, priapism, and glomerulopathy. Moreover, RBCs positive for the Duffy antigen receptor for chemokines may be very sensitive to various inflammatory molecules that promote RBC dehydration and increase RBC adhesiveness to the vascular wall. In summary, SCD is characterized by a vicious circle between abnormal RBC rheology and inflammation, which modulates the clinical severity of patients.
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Affiliation(s)
- Elie Nader
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team Vascular Biology and Red Blood Cell, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France.,Laboratoire d'Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France
| | - Marc Romana
- Laboratoire d'Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France.,Université des Antilles, UMR_S1134, BIGR, Pointe-à-Pitre, France.,Université de Paris, UMR_S1134, BIGR, INSERM, Paris, France
| | - Philippe Connes
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team Vascular Biology and Red Blood Cell, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France.,Laboratoire d'Excellence du Globule Rouge (Labex GR-Ex), PRES Sorbonne, Paris, France
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Choi SH, Park JY. Regulation of the hypoxic tumor environment in hepatocellular carcinoma using RNA interference. Cancer Cell Int 2017; 17:3. [PMID: 28053598 PMCID: PMC5209894 DOI: 10.1186/s12935-016-0374-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 12/21/2016] [Indexed: 12/15/2022] Open
Abstract
Objectives Hypoxia is the condition where tumor cells have been deprived of oxygen and has been shown to have a role of tumor development in the hepatocellular carcinoma (HCC). Methods Using PubMed online database and Google scholar web site, the terms “angiogenesis”, “apoptosis”, “RNA interference” and/or “hepatocellular carcinoma (HCC)” were searched and analyzed. Results The hypoxia inducible factors (HIFs) are transcriptional regulators that affect a homeostatic response to oxidative stress and have been identified as a key transcription activator of angiogenesis, survival, and metabolism. Cytokines, such as IL-8, also controlled endothelia cells survival and angiogenesis. IL-8 was also overexpressed under hypoxia and induced tumor angiogenesis and growth. Conclusion Therefore, regulation of HIFs and IL-8 controlled the tumor microenvironment in terms of tumor angiogenesis and apoptosis. The review summarizes the results of regulation of the hypoxic tumor environment.
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Affiliation(s)
- Sung Hoon Choi
- Division of Bioconvergence Analysis, Drug and Disease Target Group, Korea Basic Science Institute, Daejeon, Korea
| | - Jun Yong Park
- Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea
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Zhang P, Zhu D, Chen X, Li Y, Li N, Gao Q, Li L, Zhou X, Lv J, Sun M, Mao C, Xu Z. Prenatal hypoxia promotes atherosclerosis via vascular inflammation in the offspring rats. Atherosclerosis 2015; 245:28-34. [PMID: 26691907 DOI: 10.1016/j.atherosclerosis.2015.11.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/06/2015] [Accepted: 11/24/2015] [Indexed: 12/17/2022]
Abstract
BACKGROUND Hypoxia is a critical contributor to increased risks of cardiovascular diseases, including atherosclerosis, but the detailed mechanism that hypoxia leads to atherosclerosis remains unknown. METHODS Pregnant rats were treated with hypoxia (10.5% oxygen) during pregnancy, and HUVEC cells treated with 1% of oxygen. Blood lipids were tested at fetal stage and adult stage of offspring rats; the level of pro-inflammatory cytokines of HUVEC and offspring rats were investigated, and HIF-1α and NFκB mRNA level were also measured by Q-PCR and Elisa. RESULTS We found that TC, LDL-C, ox-LDL-C, and the receptors of ox-LDL-C (lox-1) of the adult offspring were significantly higher than that of the control, while HDL-C was significantly reduced in hypoxia group. The internal elastic lamina was blocked by smooth muscle cells; and the migration of smooth muscle cells into the intima were observed in hypoxia offspring. Luciferase reporter gene experiment showed that HIF-1α activated NFκB transcription at four discrete binding sites of NFκBp65 promoter, although there was no obvious difference among the four discrete binding sites. Using transfection of pCDNA3.1-HIF-1α on HUVEC cells, HIF-1α significantly activated NFκB transcription at hypoxic conditions (1% O2), and concurrent with increased expression of IL-1β and TNF-α. CONCLUSION Hypoxia during pregnancy activated NFκB transcription to induce pro-inflammatory cytokines, leading to the early stage of atherosclerosis.
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Affiliation(s)
- Pengjie Zhang
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Di Zhu
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Xionghui Chen
- Emergency Department, First Hospital of Soochow University, Suzhou, China
| | - Yongmei Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Na Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Qinqin Gao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Lingjun Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Xiuwen Zhou
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Juanxiu Lv
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Miao Sun
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Caiping Mao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Zhice Xu
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China; Center for Prenatal Biology, Loma Linda University, CA, USA.
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Hidalgo MA, Carretta MD, Teuber SE, Zárate C, Cárcamo L, Concha II, Burgos RA. fMLP-Induced IL-8 Release Is Dependent on NADPH Oxidase in Human Neutrophils. J Immunol Res 2015; 2015:120348. [PMID: 26634216 DOI: 10.1155/2015/120348] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 09/30/2015] [Accepted: 10/07/2015] [Indexed: 12/11/2022] Open
Abstract
N-Formyl-methionyl-leucyl-phenylalanine (fMLP) and platelet-activating factor (PAF) induce similar intracellular signalling profiles; but only fMLP induces interleukin-8 (IL-8) release and nicotinamide adenine dinucleotide phosphate reduced (NADPH) oxidase activity in neutrophils. Because the role of ROS on IL-8 release in neutrophils is until now controversial, we assessed if NADPH oxidase is involved in the IL-8 secretions and PI3K/Akt, MAPK, and NF-κB pathways activity induced by fMLP. Neutrophils were obtained from healthy volunteers. IL-8 was measured by ELISA, IL-8 mRNA by qPCR, and ROS production by luminol-amplified chemiluminescence, reduction of ferricytochrome c, and FACS. Intracellular pH changes were detected by spectrofluorescence. ERK1/2, p38 MAPK, and Akt phosphorylation were analysed by immunoblotting and NF-κB was analysed by immunocytochemistry. Hydroxy-3-methoxyaceto-phenone (HMAP), diphenyleneiodonium (DPI), and siRNA Nox2 reduced the ROS and IL-8 release in neutrophils treated with fMLP. HMAP, DPI, and amiloride (a Na+/H+ exchanger inhibitor) inhibited the Akt phosphorylation and did not affect the p38 MAPK and ERK1/2 activity. DPI and HMAP reduced NF-κB translocation induced by fMLP. We showed that IL-8 release induced by fMLP is dependent on NADPH oxidase, and ROS could play a redundant role in cell signalling, ultimately activating the PI3K/Akt and NF-κB pathways in neutrophils.
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Abstract
Heme is an essential molecule expressed ubiquitously all through our tissues. Heme plays major functions in cellular physiology and metabolism as the prosthetic group of diverse proteins. Once released from cells and from hemeproteins free heme causes oxidative damage and inflammation, thus acting as a prototypic damage-associated molecular pattern. In this context, free heme is a critical component of the pathological process of sterile and infectious hemolytic conditions including malaria, hemolytic anemias, ischemia-reperfusion, and hemorrhage. The plasma scavenger proteins hemopexin and albumin reduce heme toxicity and are responsible for transporting free heme to intracellular compartments where it is catabolized by heme-oxygenase enzymes. Upon hemolysis or severe cellular damage the serum capacity to scavenge heme may saturate and increase free heme to sufficient amounts to cause tissue damage in various organs. The mechanism by which heme causes reactive oxygen generation, activation of cells of the innate immune system and cell death are not fully understood. Although heme can directly promote lipid peroxidation by its iron atom, heme can also induce reactive oxygen species generation and production of inflammatory mediators through the activation of selective signaling pathways. Heme activates innate immune cells such as macrophages and neutrophils through activation of innate immune receptors. The importance of these events has been demonstrated in infectious and non-infectious diseases models. In this review, we will discuss the mechanisms behind heme-induced cytotoxicity and inflammation and the consequences of these events on different tissues and diseases.
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Affiliation(s)
- Fabianno F. Dutra
- Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de JaneiroRio de Janeiro, Brazil
| | - Marcelo T. Bozza
- Laboratório de Inflamação e Imunidade, Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de JaneiroRio de Janeiro, Brazil
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Mumby S, Ramakrishnan L, Evans TW, Griffiths MJD, Quinlan GJ. Methemoglobin-induced signaling and chemokine responses in human alveolar epithelial cells. Am J Physiol Lung Cell Mol Physiol 2013; 306:L88-100. [PMID: 24142518 DOI: 10.1152/ajplung.00066.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Diffuse alveolar hemorrhage is characterized by the presence of red blood cells and free hemoglobin in the alveoli and complicates a number of serious medical and surgical lung conditions including the pulmonary vasculitides and acute respiratory distress syndrome. In this study we investigated the hypothesis that exposure of human alveolar epithelial cells to hemoglobin and its breakdown products regulates chemokine release via iron- and oxidant-mediated activation of the transcription factor NF-κB. Methemoglobin alone stimulated the release of IL-8 and MCP-1 from A549 cells via activation of the NF-κB pathway; additionally, IL-8 required ERK activation and MCP-1 required JNK activation. Neither antioxidants nor iron chelators and knockdown of ferritin heavy and light chains affected these responses, indicating that iron and reactive oxygen species are not involved in the response of alveolar epithelial cells to methemoglobin. Incubation of primary cultures of human alveolar type 2 cells with methemoglobin resulted in a similar pattern of chemokine release and signaling pathway activation. In summary, we have shown for the first time that methemoglobin induced chemokine release from human lung epithelial cells independent of iron- and redox-mediated signaling involving the activation of the NF-κB and MAPK pathways. Decompartmentalization of hemoglobin may be a significant proinflammatory stimulus in a variety of lung diseases.
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Affiliation(s)
- Sharon Mumby
- Unit of Critical Care, Royal Brompton and Harefield NHS Foundation Trust Hospital, Sydney St., London SW3 6NP, UK.
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Sakurai A, Kinoshita K, Furukawa M, Noda A, Yamaguchi J, Kogawa R, Tanjoh K. Implication for long-term hypothermia on degradation of interleukin-8 mRNA in endothelial cells stimulated with lipopolysaccharides. Ther Hypothermia Temp Manag 2012; 2:67-72. [PMID: 23667775 PMCID: PMC3621332 DOI: 10.1089/ther.2012.0010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This experimental study investigated the effects of long-term hypothermia on the production of interleukin (IL)-8 protein and its mRNA expression in endothelial cells stimulated by lipopolysaccharides (LPS). Human umbilical vein endothelial cells were separated into a non-cooling group (N group: 37°C) and a cooling group (C group: 30°C). These groups were incubated with LPS (1 μg/mL) for 0, 2, 6, 24, 48, 72, and 96 hours. Production of the IL-8 protein secreted into the supernatant and mRNA expression in the cells were measured using enzyme-linked immunoabsorbent assay (ELISA) and real-time reverse transcription polymerase chain reaction (RT-PCR) analysis. To evaluate mRNA stability, both groups were incubated with actinomycin D at 6 hours after incubation with LPS for 24 hours. The degradation ratio was calculated by comparing the total expression of mRNA at 6 hours versus 0 hours. The protein levels in the C group were significantly lower than the N group between 6 and 96 hours. The mRNA expression in the C group was also significantly lower than in the N group up to 48 hours, but at 72 hours it was significantly higher than N group. IL-8 mRNA was less degraded in the C group compared to the N group. Under long-term hypothermia, IL-8 protein production was suppressed, while IL-8 mRNA was stabilized after LPS treatment. The potential of IL-8 to produce an inflammatory response in endothelial cells may persist even during long-term hypothermia.
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Lundvig DMS, Immenschuh S, Wagener FADTG. Heme oxygenase, inflammation, and fibrosis: the good, the bad, and the ugly? Front Pharmacol 2012; 3:81. [PMID: 22586396 PMCID: PMC3345581 DOI: 10.3389/fphar.2012.00081] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/13/2012] [Indexed: 12/13/2022] Open
Abstract
Upon injury, prolonged inflammation and oxidative stress may cause pathological wound healing and fibrosis, leading to formation of excessive scar tissue. Fibrogenesis can occur in most organs and tissues and may ultimately lead to organ dysfunction and failure. The underlying mechanisms of pathological wound healing still remain unclear, and are considered to be multifactorial, but so far, no efficient anti-fibrotic therapies exist. Extra- and intracellular levels of free heme may be increased in a variety of pathological conditions due to release from hemoproteins. Free heme possesses pro-inflammatory and oxidative properties, and may act as a danger signal. Effects of free heme may be counteracted by heme-binding proteins or by heme degradation. Heme is degraded by heme oxygenase (HO) that exists as two isoforms: inducible HO-1 and constitutively expressed HO-2. HO generates the effector molecules biliverdin/bilirubin, carbon monoxide, and free iron/ferritin. HO deficiency in mouse and man leads to exaggerated inflammation following mild insults, and accumulating epidemiological and preclinical studies support the widely recognized notion of the cytoprotective, anti-oxidative, and anti-inflammatory effects of the activity of the HO system and its effector molecules. In this review, we address the potential effects of targeted HO-1 induction or administration of HO-effector molecules as therapeutic targets in fibrotic conditions to counteract inflammatory and oxidative insults. This is exemplified by various clinically relevant conditions, such as hypertrophic scarring, chronic inflammatory liver disease, chronic pancreatitis, and chronic graft rejection in transplantation.
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Affiliation(s)
- Ditte M S Lundvig
- Department of Orthodontics and Craniofacial Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre Nijmegen, Netherlands
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Martinez-Outschoorn UE, Whitaker-Menezes D, Lin Z, Flomenberg N, Howell A, Pestell RG, Lisanti MP, Sotgia F. Cytokine production and inflammation drive autophagy in the tumor microenvironment: role of stromal caveolin-1 as a key regulator. Cell Cycle 2011; 10:1784-93. [PMID: 21566463 DOI: 10.4161/cc.10.11.15674] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recently, we proposed a new paradigm for understanding the role of the tumor microenvironment in breast cancer onset and progression. In this model, cancer cells induce oxidative stress in adjacent fibroblasts. This, in turn, results in the onset of stromal autophagy, which produces recycled nutrients to "feed" anabolic cancer cells. However, it remains unknown how autophagy in the tumor microenvironment relates to inflammation, another key driver of tumorigenesis. To address this issue, here we employed a well-characterized co-culture system in which cancer cells induce autophagy in adjacent fibroblasts via oxidative stress and NFκB-activation. We show, using this co-culture system, that the same experimental conditions that result in an autophagic microenvironment, also drive in the production of numerous inflammatory mediators (including IL-6, IL-8, IL-10, MIP1a, IFNg, RANTES (CCL5) and GMCSF). Furthermore, we demonstrate that most of these inflammatory mediators are individually sufficient to directly induce the onset of autophagy in fibroblasts. To further validate the in vivo relevance of these findings, we assessed the inflammatory status of Cav-1 (-/-) null mammary fat pads, which are a model of a bonafide autophagic microenvironment. Notably, we show that Cav-1 (-/-) mammary fat pads undergo infiltration with numerous inflammatory cell types, including lymphocytes, T-cells, macrophages and mast cells. Taken together, our results suggest that cytokine production and inflammation are key drivers of autophagy in the tumor microenvironment. These results may explain why a loss of stromal Cav-1 is a powerful predictor of poor clinical outcome in breast cancer patients, as it is a marker of both (1) autophagy and (2) inflammation in the tumor microenvironment. Lastly, hypoxia in fibroblasts was not sufficient to induce the full-blown inflammatory response that we observed during the co-culture of fibroblasts with cancer cells, indicating that key reciprocal interactions between cancer cells and fibroblasts may be required.
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Hao K, Hanawa H, Ding L, Ota Y, Yoshida K, Toba K, Ogura M, Ito H, Kodama M, Aizawa Y. Free heme is a danger signal inducing expression of proinflammatory proteins in cultured cells derived from normal rat hearts. Mol Immunol 2011; 48:1191-202. [PMID: 21470686 DOI: 10.1016/j.molimm.2011.02.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 02/07/2011] [Accepted: 02/28/2011] [Indexed: 12/31/2022]
Abstract
Endogenous molecules from damaged tissue act as danger signals to trigger or amplify the immune/inflammatory response. In this study, we examined whether free heme induced pro-inflammatory proteins in cultured cells derived from normal hearts and investigated the cells targeted by heme, together with its mechanism of action in these cells. We cultured collagenase-isolated heart-derived cells from normal rats and examined whether free heme induced pro-inflammatory proteins, reactive oxygen species (ROS) production and NF-κB activation, by quantitative RT-PCR, ELISA and flow cytometry. Free heme increased mRNA of various pro-inflammatory proteins in cultured cardiac resident cells (CCRC) (at least 100-fold) and induced intracellular ROS formation. Approximately 85-90% of CCRC are fibroblast/smooth muscle cells and 10-15% are CD11bc-positive macrophages; therefore to examine individual target cells, macrophage-deleted (CD11bc-negative) CCRC, primary cultured cells (cardiac fibroblasts, arterial smooth muscle cells and cardiac microvascular endothelial cells) and macrophage cells lines (NR8383) were similarly treated. Free heme activated NF-κB and induced expression of some pro-inflammatory proteins, including IL-1 and TNF-α in NR8383. On the other hand, macrophage-deleted CCRC strongly increased expression of these proteins on treatment with IL-1 or TNF-α, but not free heme. Induction of expression of pro-inflammatory proteins by free heme was not inhibited by intracellular ROS reduction, but by protease and proteasome inhibitors capable of regulating NF-κB. These data suggest that free heme strongly induces various pro-inflammatory proteins in injured hearts through NF-κB activation in cardiac resident macrophages and through cross-talk between macrophages and fibroblast/smooth muscle cells mediated inter alia by IL-1, TNF-α.
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Affiliation(s)
- Kazuhisa Hao
- Division of Cardiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Niigata 951-8120, Japan
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Abstract
The hypoxia-inducible factor (HIF) family of transcription factors is responsible for coordinating the cellular response to low oxygen levels in animals. By regulating the expression of a large array of target genes during hypoxia, these proteins also direct adaptive changes in the hematopoietic, cardiovascular, and respiratory systems. They also play roles in pathological processes, including tumorogenesis. In recent years, several oxygenases have been identified as key molecular oxygen sensors within the HIF system. The HIF hydroxylases regulate the stability and transcriptional activity of the HIF-alpha subunit by catalyzing hydroxylation of specific proline and asparaginyl residues, respectively. They require oxygen and 2-oxoglutarate (2OG) as co-substrates, and depend upon non-heme ferrous iron (Fe(II)) as a cofactor. This article summarizes current understanding of the biochemistry of the HIF hydroxylases, identifies targets for their pharmacological manipulation, and discusses their potential in the therapeutic manipulation of the HIF system.
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Affiliation(s)
- Simon Nagel
- Acute Stroke Programme, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Headington, Oxford, United Kingdom
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16
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Fernandes AF, Bian Q, Jiang JK, Thomas CJ, Taylor A, Pereira P, Shang F. Proteasome inactivation promotes p38 mitogen-activated protein kinase-dependent phosphatidylinositol 3-kinase activation and increases interleukin-8 production in retinal pigment epithelial cells. Mol Biol Cell 2009; 20:3690-9. [PMID: 19570915 DOI: 10.1091/mbc.e08-10-1068] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Oxidative stress and inflammation are implicated in the pathogenesis of many age-related diseases. We have demonstrated previously that oxidative inactivation of the proteasome is a molecular link between oxidative stress and overexpression of interleukin (IL)-8. Here, we elucidated a novel signaling cascade that leads to up-regulation of IL-8 in response to proteasome inactivation. The sequence of events in this cascade includes proteasome inactivation, activation of mitogen-activated protein kinase kinase (MKK)3/MKK6, activation of p38 mitogen-activated protein kinase (MAPK), epidermal growth factor receptor phosphorylation, phosphatidylinositol 3-kinase (PI3K) activation and increased IL-8 expression. Blocking any of these signaling pathways abolished the up-regulation of IL-8 induced by proteasome inhibition. Although Akt is also activated in response to proteasome inactivation, we found that the PI3K-dependent up-regulation of IL-8 is independent of 3-phosphoinositide-dependent protein kinase (PDK)1 and Akt. Inhibition of PDK1 and Akt with chemical inhibitors or expression of constitutive active Akt had little effects on IL-8 expression in response to proteasome inactivation. In contrast, inhibition of interleukin 2-inducible T cell kinase, a kinase downstream of PI3K, significantly reduced the expression and secretion of IL-8 in response to proteasome inactivation. Together, these data elucidate a novel signaling network that leads to increased IL-8 production in response to proteasome inactivation.
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Affiliation(s)
- Alexandre F Fernandes
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA
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17
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Mitchell RM, Lee SY, Randazzo WT, Simmons Z, Connor JR. Influence of HFE variants and cellular iron on monocyte chemoattractant protein-1. J Neuroinflammation 2009; 6:6. [PMID: 19228389 PMCID: PMC2656486 DOI: 10.1186/1742-2094-6-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Accepted: 02/19/2009] [Indexed: 08/30/2023] Open
Abstract
Background Polymorphisms in the MHC class 1-like gene known as HFE have been proposed as genetic modifiers of neurodegenerative diseases that include neuroinflammation as part of the disease process. Variants of HFE are relatively common in the general population and are most commonly associated with iron overload, but can promote subclinical cellular iron loading even in the absence of clinically identified disease. The effects of the variants as well as the resulting cellular iron dyshomeostasis potentially impact a number of disease-associated pathways. We tested the hypothesis that the two most common HFE variants, H63D and C282Y, would affect cellular secretion of cytokines and trophic factors. Methods We screened a panel of cytokines and trophic factors using a multiplexed immunoassay in human neuroblastoma SH-SY5Y cells expressing different variants of HFE. The influence of cellular iron secretion on the potent chemokine monocyte chemoattractant protein-1 (MCP-1) was assessed using ferric ammonium citrate and the iron chelator, desferroxamine. Additionally, an antioxidant, Trolox, and an anti-inflammatory, minocycline, were tested for their effects on MCP-1 secretion in the presence of HFE variants. Results Expression of the HFE variants altered the labile iron pool in SH-SY5Y cells. Of the panel of cytokines and trophic factors analyzed, only the release of MCP-1 was affected by the HFE variants. We further examined the relationship between iron and MCP-1 and found MCP-1 secretion tightly associated with intracellular iron status. A potential direct effect of HFE is considered because, despite having similar levels of intracellular iron, the association between HFE genotype and MCP-1 expression was different for the H63D and C282Y HFE variants. Moreover, HFE genotype was a factor in the effect of minocycline, a multifaceted antibiotic used in treating a number of neurologic conditions associated with inflammation, on MCP-1 secretion. Conclusion Our results demonstrate that HFE polymorphisms influence the synthesis and release of MCP-1. The mechanism of action involves cellular iron status but it appears there could be additional influences such as ER stress. Finally, these data demonstrate a pharmacogenetic effect of HFE polymorphisms on the ability of minocycline to inhibit MCP-1 secretion.
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Affiliation(s)
- Ryan M Mitchell
- George M Leader Family Laboratory, Department of Neurosurgery, Pennsylvania State University College of Medicine/Milton S Hershey Medical Center, Hershey, PA 17033, USA.
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