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Wu K, Tian S, Zhou H, Wu Y. Statins protect human endothelial cells from TNF-induced inflammation via ERK5 activation. Biochem Pharmacol 2013; 85:1753-60. [PMID: 23608189 DOI: 10.1016/j.bcp.2013.04.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/09/2013] [Accepted: 04/12/2013] [Indexed: 12/21/2022]
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) exert pleiotropic effects on the cardiovascular system, in part through a decrease in reactive oxygen species (ROS) formation and reduction of vascular inflammation. To elucidate the molecular mechanisms involved in these effects, we investigated the effect of statins on TNF-α-induced ROS production, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) expression in human aortic endothelial cells (HAECs). Exposure of HAECs to TNF-α caused production of ROS via Rac-1 membrane translocation and activation. The Rac-1 activation and ROS liberation mediated TNF-stimulated NF-κB activation and the subsequent VCAM-1 and ICAM-1 expression. Extracellular-signal-regulated kinase 5 (ERK5) plays a central role in inhibiting endothelial inflammation. Immune complex kinase assay of protein extracts from HAECs treated with atorvastatin revealed increased ERK5 activity in a time- and dose-dependent manner. In addition, pretreatment with atorvastatin inhibited TNF-α-induced ROS production and VCAM-1 and ICAM-1 expression. Chemical or genetic inhibition of ERK5 ablated the statins inhibition of Rac-1 activation, ROS formation, NF-κB, VCAM-1 and ICAM-1 expression induced by TNF-α. Taken together, statins, via ERK5 activation, suppress TNF-stimulated Rac-1 activation, ROS generation, NF-κB activation and VCAM-1 and ICAM-1 expression in human ECs, which provides a novel explanation for the pleiotropic effects of statins that benefit the cardiovascular system.
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Affiliation(s)
- Ke Wu
- Center for Animal Experiment/ABSL-3 Laboratory, Wuhan University, Hubei 430071, China
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102
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Kim M, Kim S, Lim JH, Lee C, Choi HC, Woo CH. Laminar flow activation of ERK5 protein in vascular endothelium leads to atheroprotective effect via NF-E2-related factor 2 (Nrf2) activation. J Biol Chem 2012; 287:40722-31. [PMID: 23043106 DOI: 10.1074/jbc.m112.381509] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Laminar flow protects from atherosclerosis in endothelium. RESULTS Laminar flow induces Nrf2 activation dependent on ERK5 activation, leading to up-regulation of downstream genes of Nrf2. CONCLUSION ERK5 requires Nrf2 activation to exert cytoprotective effect on HUVEC. ERK5 inhibitor BIX02189 regulates Nrf2 activation in vivo. SIGNIFICANCE Identifying ERK5 as a molecular target for regulating flow-mediating Nrf2-dependent gene expression may have significant therapeutic potential for treating atherosclerosis. Atherosclerosis is often observed in areas where disturbed flow is formed, whereas atheroprotective region is found in areas where steady laminar flow is developed. It has been reported that some genes activated by blood flow play important roles in vascular function and pathogenesis of atherosclerosis. Extracellular signal-regulated kinase 5 (ERK5) has been reported to regulate endothelial integrity and protect from vascular dysfunction and disease under laminar flow. Krüppel-like factor 2 (KLF2) and NF-E2-related factor 2 (Nrf2) are major transcriptional factors that contribute to anti-atherogenic responses under laminar flow. Implication of ERK5 in laminar flow-mediated regulation of KLF2-dependent gene has been established, whereas the role of ERK5 in laminar flow-mediated activation of Nrf2 pathway has not been addressed yet. In this study, we found that the blockage of ERK5 either by genetic depletion with siRNA or by biochemical inactivation with a specific chemical compound inhibited laminar flow-induced up-regulation of Nrf2-dependent gene expressions, whereas activation of ERK5 increased transcriptional activity and nuclear translocation of Nrf2, which suggests that ERK5 mediates laminar flow-induced up-regulation of Nrf2-dependent gene expression. Further functional studies showed that ERK5 provides protection against oxidative stress-induced cytotoxicity dependent on Nrf2. Molecular interaction between ERK5 and Nrf2 was further induced by laminar flow. Finally, flow-dependent nuclear localization of Nrf2 was inhibited by BIX02189, a specific inhibitor of MEK5, in aorta of mice in vivo. Collectively, these data demonstrate that laminar flow-induced activation of ERK5-Nrf2 signal pathway plays a critical role for anti-inflammatory and anti-apoptotic mechanism in endothelial cells.
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Affiliation(s)
- Miso Kim
- Department of Pharmacology, Yeungnam University College of Medicine, 317-1 Daemyung-dong, Daegu 705-717, Korea
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103
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Alaiti MA, Orasanu G, Tugal D, Lu Y, Jain MK. Kruppel-like factors and vascular inflammation: implications for atherosclerosis. Curr Atheroscler Rep 2012; 14:438-49. [PMID: 22850980 PMCID: PMC4410857 DOI: 10.1007/s11883-012-0268-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Mohamad Amer Alaiti
- Harrington Heart and Vascular Institute and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, 2103 Cornell Road, Room 4-522, Cleveland, OH 44106, USA
| | - Gabriela Orasanu
- Harrington Heart and Vascular Institute and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, 2103 Cornell Road, Room 4-522, Cleveland, OH 44106, USA
| | - Derin Tugal
- Harrington Heart and Vascular Institute and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, 2103 Cornell Road, Room 4-522, Cleveland, OH 44106, USA
| | - Yuan Lu
- Harrington Heart and Vascular Institute and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, 2103 Cornell Road, Room 4-522, Cleveland, OH 44106, USA
| | - Mukesh K. Jain
- Harrington Heart and Vascular Institute and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, 2103 Cornell Road, Room 4-522, Cleveland, OH 44106, USA
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Salmon M, Gomez D, Greene E, Shankman L, Owens GK. Cooperative binding of KLF4, pELK-1, and HDAC2 to a G/C repressor element in the SM22α promoter mediates transcriptional silencing during SMC phenotypic switching in vivo. Circ Res 2012; 111:685-96. [PMID: 22811558 DOI: 10.1161/circresaha.112.269811] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
RATIONALE We previously identified conserved G/C Repressor elements in the promoters of most smooth muscle cell (SMC) marker genes and demonstrated that mutation of this element within the SM22α promoter nearly abrogated repression of this transgene after vascular wire injury or within lesions of ApoE-/- mice. However, the mechanisms regulating the activity of the G/C Repressor are unknown, although we have previously shown that phenotypic switching of cultured SMC is dependent on Krupple-like factor (KLF)4. OBJECTIVE The goals of the present studies were to ascertain if (1) injury-induced repression of SM22α gene after vascular injury is mediated through KLF4 binding to the G/C Repressor element and (2) the transcriptional repressor activity of KLF4 on SMC marker genes is dependent on cooperative binding with pELK-1 (downstream activator of the mitogen-activated protein kinase pathway) and subsequent recruitment of histone de-acetylase 2 (HDAC2), which mediates epigenetic gene silencing. METHODS AND RESULTS Chromatin immunoprecipitation (ChIP) assays were performed on chromatin derived from carotid arteries of mice having either a wild-type or G/C Repressor mutant SM22α promoter-LacZ transgene. KLF4 and pELK-1 binding to the SM22α promoter was markedly increased after vascular injury and was G/C Repressor dependent. Sequential ChIP assays and proximity ligation analyses in cultured SMC treated with platelet-derived growth factor BB or oxidized phospholipids showed formation of a KLF4, pELK-1, and HDAC2 multiprotein complex dependent on the SM22α G/C Repressor element. CONCLUSIONS Silencing of SMC marker genes during phenotypic switching is partially mediated by sequential binding of pELK-1 and KLF4 to G/C Repressor elements. The pELK-1-KLF4 complex in turn recruits HDAC2, leading to reduced histone acetylation and epigenetic silencing.
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Affiliation(s)
- Morgan Salmon
- University of Virginia, School of Medicine, Robert M. Berne Cardiovascular Research Center, PO Box 801394, Charlottesville, VA 22908-1394, USA
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105
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Min KW, Zhang X, Imchen T, Baek SJ. A peroxisome proliferator-activated receptor ligand MCC-555 imparts anti-proliferative response in pancreatic cancer cells by PPARgamma-independent up-regulation of KLF4. Toxicol Appl Pharmacol 2012; 263:225-32. [PMID: 22750490 DOI: 10.1016/j.taap.2012.06.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/19/2012] [Accepted: 06/22/2012] [Indexed: 12/20/2022]
Abstract
MCC-555 is a novel PPARα/γ dual ligand of the thiazolidinedione class and was recently developed as an anti-diabetic drug with unique properties. MCC-555 also has anti-proliferative activity through growth inhibition and apoptosis induction in several cancer cell types. Our group has shown that MCC-555 targets several proteins in colorectal tumorigenesis including nonsteroidal anti-inflammatory drug (NSAID)-activated gene (NAG-1) which plays an important role in chemoprevention responsible for chemopreventive compounds. NAG-1 is a member of the TGF-β superfamily and is involved in tumor progression and development; however, NAG-1's roles in pancreatic cancer have not been studied. In this report, we found that MCC-555 alters not only NAG-1 expression, but also p21 and cyclin D1 expression. NAG-1 and p21 expression was not blocked by PPARγ-specific antagonist GW9662, suggesting that MCC-555-induced NAG-1 and p21 expression is independent of PPARγ activation. However, decreasing cyclin D1 by MCC-555 seems to be affected by PPARγ activation. Further, we found that the GC box located in the NAG-1 promoter play an important role in NAG-1 transactivation by MCC-555. Subsequently, we screened several transcription factors that may bind to the GC box region in the NAG-1 promoter and found that KLF4 potentially binds to this region. Expression of KLF4 precedes NAG-1 and p21 expression in the presence of MCC-555, whereas blocking KLF4 expression using specific KLF4 siRNA showed that both NAG-1 and p21 expression by MCC-555 was blocked. In conclusion, MCC-555's actions on anti-proliferation involve both PPARγ-dependent and -independent pathways, thereby enhancing anti-tumorigenesis in pancreatic cancer cells.
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Affiliation(s)
- Kyung-Won Min
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA
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106
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Mechanotransduction in embryonic vascular development. Biomech Model Mechanobiol 2012; 11:1149-68. [PMID: 22744845 DOI: 10.1007/s10237-012-0412-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 06/09/2012] [Indexed: 12/25/2022]
Abstract
A plethora of biochemical signals provides spatial and temporal cues that carefully orchestrate the complex process of vertebrate embryonic development. The embryonic vasculature develops not only in the context of these biochemical cues, but also in the context of the biomechanical forces imparted by blood flow. In the mature vasculature, different blood flow regimes induce distinct genetic programs, and significant progress has been made toward understanding how these forces are perceived by endothelial cells and transduced into biochemical signals. However, it cannot be assumed that paradigms that govern the mature vasculature are pertinent to the developing embryonic vasculature. The embryonic vasculature can respond to the mechanical forces of blood flow, and these responses are critical in vascular remodeling, certain aspects of sprouting angiogenesis, and maintenance of arterial-venous identity. Here, we review data regarding mechanistic aspects of endothelial cell mechanotransduction, with a focus on the response to shear stress, and elaborate upon the multifarious effects of shear stress on the embryonic vasculature. In addition, we discuss emerging predictive vascular growth models and highlight the prospect of combining signaling pathway information with computational modeling. We assert that correlation of precise measurements of hemodynamic parameters with effects on endothelial cell gene expression and cell behavior is required for fully understanding how blood flow-induced loading governs normal vascular development and shapes congenital cardiovascular abnormalities.
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107
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108
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Abstract
Mss4 (mammalian suppressor of Sec4) is an evolutionarily highly conserved protein and shows high sequence and structural similarity to nucleotide exchange factors. Although Mss4 tightly binds a series of exocytic Rab GTPases, it exercises only a low catalytic activity. Therefore Mss4 was proposed to work rather as a chaperone, protecting nucleotide free Rabs from degradation than as a nucleotide exchange factor. Here we provide further evidence for chaperone-like properties of Mss4. We show that expression levels of cellular Mss4 mRNA and protein are rapidly changed in response to a broad range of extracellular stress stimuli. The alterations are regulated mostly via the (c-jun NH2-terminal kinase) JNK stress MAPK signaling pathway and the mode of regulation resembles that of heat shock proteins. Similar to heat shock proteins, upregulation of Mss4 after stress stimulation functions protectively against the programmed cell death. Molecular analysis of the Mss4-mediated inhibition of apoptosis showed that interaction of Mss4 with eIF3f (eukaryotic translation initiation factor 3 subunit f), a member of the translation initiation complex and a protein with distinct pro-apoptotic properties, is the critical event in the anti-apoptotic action of Mss4.
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109
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Masud R, Shameer K, Dhar A, Ding K, Kullo IJ. Gene expression profiling of peripheral blood mononuclear cells in the setting of peripheral arterial disease. J Clin Bioinforma 2012; 2:6. [PMID: 22409835 PMCID: PMC3381689 DOI: 10.1186/2043-9113-2-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 03/12/2012] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Peripheral arterial disease (PAD) is a relatively common manifestation of systemic atherosclerosis that leads to progressive narrowing of the lumen of leg arteries. Circulating monocytes are in contact with the arterial wall and can serve as reporters of vascular pathology in the setting of PAD. We performed gene expression analysis of peripheral blood mononuclear cells (PBMC) in patients with PAD and controls without PAD to identify differentially regulated genes. METHODS PAD was defined as an ankle brachial index (ABI) ≤0.9 (n = 19) while age and gender matched controls had an ABI > 1.0 (n = 18). Microarray analysis was performed using Affymetrix HG-U133 plus 2.0 gene chips and analyzed using GeneSpring GX 11.0. Gene expression data was normalized using Robust Multichip Analysis (RMA) normalization method, differential expression was defined as a fold change ≥1.5, followed by unpaired Mann-Whitney test (P < 0.05) and correction for multiple testing by Benjamini and Hochberg False Discovery Rate. Meta-analysis of differentially expressed genes was performed using an integrated bioinformatics pipeline with tools for enrichment analysis using Gene Ontology (GO) terms, pathway analysis using Kyoto Encyclopedia of Genes and Genomes (KEGG), molecular event enrichment using Reactome annotations and network analysis using Ingenuity Pathway Analysis suite. Extensive biocuration was also performed to understand the functional context of genes. RESULTS We identified 87 genes differentially expressed in the setting of PAD; 40 genes were upregulated and 47 genes were downregulated. We employed an integrated bioinformatics pipeline coupled with literature curation to characterize the functional coherence of differentially regulated genes. CONCLUSION Notably, upregulated genes mediate immune response, inflammation, apoptosis, stress response, phosphorylation, hemostasis, platelet activation and platelet aggregation. Downregulated genes included several genes from the zinc finger family that are involved in transcriptional regulation. These results provide insights into molecular mechanisms relevant to the pathophysiology of PAD.
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Affiliation(s)
- Rizwan Masud
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester MN 55905, USA
| | - Khader Shameer
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester MN 55905, USA
| | - Aparna Dhar
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester MN 55905, USA
| | - Keyue Ding
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester MN 55905, USA
| | - Iftikhar J Kullo
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester MN 55905, USA
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110
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García-Hoz C, Sánchez-Fernández G, García-Escudero R, Fernández-Velasco M, Palacios-García J, Ruiz-Meana M, Díaz-Meco MT, Leitges M, Moscat J, García-Dorado D, Boscá L, Mayor F, Ribas C. Protein kinase C (PKC)ζ-mediated Gαq stimulation of ERK5 protein pathway in cardiomyocytes and cardiac fibroblasts. J Biol Chem 2012; 287:7792-802. [PMID: 22232556 PMCID: PMC3293562 DOI: 10.1074/jbc.m111.282210] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Gq-coupled G protein-coupled receptors (GPCRs) mediate the actions of a variety of messengers that are key regulators of cardiovascular function. Enhanced Gα(q)-mediated signaling plays an important role in cardiac hypertrophy and in the transition to heart failure. We have recently described that Gα(q) acts as an adaptor protein that facilitates PKCζ-mediated activation of ERK5 in epithelial cells. Because the ERK5 cascade is known to be involved in cardiac hypertrophy, we have investigated the potential relevance of this pathway in cardiovascular Gq-dependent signaling using both cultured cardiac cell types and chronic administration of angiotensin II in mice. We find that PKCζ is required for the activation of the ERK5 pathway by Gq-coupled GPCR in neonatal and adult murine cardiomyocyte cultures and in cardiac fibroblasts. Stimulation of ERK5 by angiotensin II is blocked upon pharmacological inhibition or siRNA-mediated silencing of PKCζ in primary cultures of cardiac cells and in neonatal cardiomyocytes isolated from PKCζ-deficient mice. Moreover, upon chronic challenge with angiotensin II, these mice fail to promote the changes in the ERK5 pathway, in gene expression patterns, and in hypertrophic markers observed in wild-type animals. Taken together, our results show that PKCζ is essential for Gq-dependent ERK5 activation in cardiomyocytes and cardiac fibroblasts and indicate a key cardiac physiological role for the Gα(q)/PKCζ/ERK5 signaling axis.
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Affiliation(s)
- Carlota García-Hoz
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
| | - Guzmán Sánchez-Fernández
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
| | - Ramón García-Escudero
- the Molecular Oncology Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, 28040 Madrid, Spain
| | | | - Julia Palacios-García
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
| | - Marisol Ruiz-Meana
- the Vall d'Hebron University Hospital and Research Institute, Universitat Autonoma de Barcelona, 08035 Barcelona, Spain
| | - Maria Teresa Díaz-Meco
- the Tumor Microenvironment Program, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - Michael Leitges
- The Biotechnology Centre of Oslo, University of Oslo, 0317 Oslo, Norway, and
| | - Jorge Moscat
- the Tumor Microenvironment Program, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - David García-Dorado
- the Vall d'Hebron University Hospital and Research Institute, Universitat Autonoma de Barcelona, 08035 Barcelona, Spain
| | - Lisardo Boscá
- the Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, 28029 Madrid, Spain
| | - Federico Mayor
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
- To whom correspondence may be addressed: Centro de Biología Molecular “Severo Ochoa,” Universidad Autónoma de Madrid, 28049 Madrid, Spain. Tel.: 34-91-1964626; Fax: 34-91-1964420; E-mail:
| | - Catalina Ribas
- From the Departamento de Biología Molecular and Centro de Biología Molecular “Severo Ochoa,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), 28049 Madrid, Universidad Autónoma de Madrid, Spain
- the Instituto de Investigación Sanitaria La Princesa, 28006 Madrid, Spain
- To whom correspondence may be addressed: Centro de Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid, 28049 Madrid, Spain. Tel.: 34-91-1964640; Fax: 34-91-1964420; E-mail:
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Abstract
PURPOSE OF REVIEW Statins have diverse effects on the cellular mediators of inflammation and immunity that may be partially responsible for their efficacy in preventing cardiovascular disease, and which have encouraged their use in treating immune/inflammatory diseases. We discuss a selection of recently published studies that provide new insights into the mechanisms by which statins exert anti-inflammatory effects. RECENT FINDINGS Statins have a variety of direct effects on the gene expression and function of cells of both the innate and adaptive immune systems, including endothelial cells, macrophages, dendritic cells and T cells. Many of these effects are related to statin blockade of GTPase isoprenylation, as has been shown in older literature, although newly identified cell type-specific downstream pathways of GTPase have been described. Recently published analyses of data from clinical trials have also provided further evidence that statin therapy has anti-inflammatory effects and benefits independent of lowering cholesterol. SUMMARY Ongoing research continues to strengthen the case that statins can modulate immune responses by several mechanisms, independent of lowering blood cholesterol. A major challenge for investigators will be to determine how to take advantage of these new mechanistic insights to improve treatment of cardiovascular disease and primary immune/inflammatory disorders.
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Affiliation(s)
- De-xiu Bu
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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112
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Current world literature. Curr Opin Lipidol 2011; 22:231-6. [PMID: 21562387 DOI: 10.1097/mol.0b013e328347aeca] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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113
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Endothelial cell activation by antiphospholipid antibodies is modulated by Kruppel-like transcription factors. Blood 2011; 117:6383-91. [PMID: 21482710 DOI: 10.1182/blood-2010-10-313072] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Antiphospholipid syndrome is characterized by thrombosis and/or recurrent pregnancy loss in the presence of antiphospholipid antibodies (APLAs). The majority of APLAs are directed against phospholipid-binding proteins, particularly β₂-glycoprotein I (β₂GPI). Anti-β₂GPI antibodies activate endothelial cells in a β₂GPI-dependent manner through a pathway that involves NF-κB. Krüppel-like factors (KLFs) play a critical role in regulating the endothelial response to inflammatory stimuli. We hypothesized that activation of endothelial cells by APLA/anti-β₂GPI antibodies might be associated with decreased expression of KLFs, which in turn might facilitate cellular activation mediated through NF-κB. Our experimental results confirmed this hypothesis, demonstrating markedly decreased expression of KLF2 and KLF4 after incubation of cells with APLA/anti-β₂GPI antibodies. Restoration of KLF2 or KLF4 levels inhibited NF-κB transcriptional activity and blocked APLA/anti-β₂GPI-mediated endothelial activation despite NF-κB p65 phosphorylation. Chromatin immunoprecipitation analysis demonstrated that inhibition of NF-κB transcriptional activity by KLFs reflects sequestration of the cotranscriptional activator CBP/p300, making this cofactor unavailable to NF-κB. These findings suggest that the endothelial response to APLA/anti-β₂GPI antibodies reflects competition between KLFs and NF-κB for their common cofactor, CBP/p300. Taken together, these observations are the first to implicate the KLFs as novel participants in the endothelial proinflammatory response to APLA/anti-β₂GPI antibodies.
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