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Inflammation-Related Risk Loci in Genome-Wide Association Studies of Coronary Artery Disease. Cells 2021; 10:cells10020440. [PMID: 33669721 PMCID: PMC7921935 DOI: 10.3390/cells10020440] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/02/2021] [Accepted: 02/17/2021] [Indexed: 12/13/2022] Open
Abstract
Although the importance of inflammation in atherosclerosis is now well established, the exact molecular processes linking inflammation to the development and course of the disease are not sufficiently understood. In this context, modern genetics—as applied by genome-wide association studies (GWAS)—can serve as a comprehensive and unbiased tool for the screening of potentially involved pathways. Indeed, a considerable proportion of loci discovered by GWAS is assumed to affect inflammatory processes. Despite many well-replicated association findings, however, translating genomic hits to specific molecular mechanisms remains challenging. This review provides an overview of the currently most relevant inflammation-related GWAS findings in coronary artery disease and explores their potential clinical perspectives.
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Singh PK, Khatri I, Jha A, Pretto CD, Spindler KR, Arumugaswami V, Giri S, Kumar A, Bhasin MK. Determination of system level alterations in host transcriptome due to Zika virus (ZIKV) Infection in retinal pigment epithelium. Sci Rep 2018; 8:11209. [PMID: 30046058 PMCID: PMC6060127 DOI: 10.1038/s41598-018-29329-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/10/2018] [Indexed: 12/26/2022] Open
Abstract
Previously, we reported that Zika virus (ZIKV) causes ocular complications such as chorioretinal atrophy, by infecting cells lining the blood-retinal barrier, including the retinal pigment epithelium (RPE). To understand the molecular basis of ZIKV-induced retinal pathology, we performed a meta-analysis of transcriptome profiles of ZIKV-infected human primary RPE and other cell types infected with either ZIKV or other related flaviviruses (Japanese encephalitis, West Nile, and Dengue). This led to identification of a unique ZIKV infection signature comprising 43 genes (35 upregulated and 8 downregulated). The major biological processes perturbed include SH3/SH2 adaptor activity, lipid and ceramide metabolism, and embryonic organ development. Further, a comparative analysis of some differentially regulated genes (ABCG1, SH2B3, SIX4, and TNFSF13B) revealed that ZIKV induced their expression relatively more than dengue virus did in RPE. Importantly, the pharmacological inhibition of ABCG1, a membrane transporter of cholesterol, resulted in reduced ZIKV infectivity. Interestingly, the ZIKV infection signature revealed the downregulation of ALDH5A1 and CHML, genes implicated in neurological (cognitive impairment, expressive language deficit, and mild ataxia) and ophthalmic (choroideremia) disorders, respectively. Collectively, our study revealed that ZIKV induces differential gene expression in RPE cells, and the identified genes/pathways (e.g., ABCG1) could potentially contribute to ZIKV-associated ocular pathologies.
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Affiliation(s)
- Pawan Kumar Singh
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, Detroit, MI, USA
| | - Indu Khatri
- BIDMC Genomics, Proteomics, Bioinformatics and Systems Biology Centre, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Alokkumar Jha
- BIDMC Genomics, Proteomics, Bioinformatics and Systems Biology Centre, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Carla D Pretto
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Katherine R Spindler
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | | | - Shailendra Giri
- Department of Neurology, Henry Ford Health System, Detroit, MI, USA
| | - Ashok Kumar
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, Detroit, MI, USA.
- Department of Biochemistry, Microbiology, and Immunology, Wayne State University, Detroit, MI, USA.
| | - Manoj K Bhasin
- BIDMC Genomics, Proteomics, Bioinformatics and Systems Biology Centre, Beth Israel Deaconess Medical Center, Boston, MA, USA.
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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Naudin C, Chevalier C, Roche S. The role of small adaptor proteins in the control of oncogenic signalingr driven by tyrosine kinases in human cancer. Oncotarget 2017; 7:11033-55. [PMID: 26788993 PMCID: PMC4905456 DOI: 10.18632/oncotarget.6929] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/01/2016] [Indexed: 12/15/2022] Open
Abstract
Protein phosphorylation on tyrosine (Tyr) residues has evolved as an important mechanism to coordinate cell communication in multicellular organisms. The importance of this process has been revealed by the discovery of the prominent oncogenic properties of tyrosine kinases (TK) upon deregulation of their physiological activities, often due to protein overexpression and/or somatic mutation. Recent reports suggest that TK oncogenic signaling is also under the control of small adaptor proteins. These cytosolic proteins lack intrinsic catalytic activity and signal by linking two functional members of a catalytic pathway. While most adaptors display positive regulatory functions, a small group of this family exerts negative regulatory functions by targeting several components of the TK signaling cascade. Here, we review how these less studied adaptor proteins negatively control TK activities and how their loss of function induces abnormal TK signaling, promoting tumor formation. We also discuss the therapeutic consequences of this novel regulatory mechanism in human oncology.
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Affiliation(s)
- Cécile Naudin
- CNRS UMR5237, University Montpellier, CRBM, Montpellier, France.,Present address: INSERM U1016, CNRS UMR8104, Institut Cochin, Paris, France
| | - Clément Chevalier
- CNRS UMR5237, University Montpellier, CRBM, Montpellier, France.,Present address: SFR Biosit (UMS CNRS 3480/US INSERM 018), MRic Photonics Platform, University Rennes, Rennes, France
| | - Serge Roche
- CNRS UMR5237, University Montpellier, CRBM, Montpellier, France.,Equipe Labellisée LIGUE 2014, Ligue Contre le Cancer, Paris, France
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Christiansen MK, Larsen SB, Nyegaard M, Neergaard-Petersen S, Würtz M, Grove EL, Hvas AM, Jensen HK, Kristensen SD. The SH2B3 and KCNK5 loci may be implicated in regulation of platelet count, volume, and maturity. Thromb Res 2017; 158:86-92. [PMID: 28865245 DOI: 10.1016/j.thromres.2017.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/21/2017] [Accepted: 08/17/2017] [Indexed: 01/11/2023]
Abstract
INTRODUCTION In recent genome-wide association studies, coronary artery disease (CAD) and myocardial infarction (MI) have been linked to a number of genetic variants, but their role in thrombopoiesis is largely unknown. AIM We investigated the association between CAD and MI-associated genetic variants and five thrombopoiesis-related indices: platelet count (PC), mean platelet volume (MPV), immature platelet count (IPC), immature platelet fraction (IPF), and serum thrombopoietin (TPO). METHODS We genotyped 45 genome-wide significant CAD/MI-markers in 879 stable CAD patients. A genetic risk score was calculated to assess the combined risk associated with all the genetic variants. Platelet indices were analysed using the Sysmex XE-2100 haematology analyser. TPO was measured by ELISA. RESULTS Two variants were nominally associated with several indices; for rs10947789 (KCNK5), the adjusted geometric mean was 2% higher for MPV (95% confidence interval: 1-2%, p=0.002), 6% for IPC (0-12%, p=0.033), and 9% for IPF (3-16%, p=0.004) per CAD risk allele. Moreover, an 11% lower TPO (3-19%, p=0.010) was observed. Rs3184504 (SH2B3) was associated with a higher adjusted geometric mean of 3% (1-6%, p=0.003) per CAD risk allele for PC, and an 11% (5-17%, p<0.001) lower TPO. Furthermore, the adjusted IPC was 5% (0-9%, p=0.037) lower per CAD risk allele for PC, whereas IPF levels did not vary across genotypes. CONCLUSION As a novel finding, our study suggests a role for KCNK5 in the regulation of platelet size and maturity. Furthermore, our findings confirm an association between the SH2B3-locus and platelet count.
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Affiliation(s)
- Morten K Christiansen
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark; Faculty of Health, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Sanne B Larsen
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.
| | - Mette Nyegaard
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Morten Würtz
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Erik L Grove
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark; Faculty of Health, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Anne-Mette Hvas
- Faculty of Health, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
| | - Henrik K Jensen
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark; Faculty of Health, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Steen D Kristensen
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark; Faculty of Health, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Blass G, Mattson DL, Staruschenko A. The function of SH2B3 (LNK) in the kidney. Am J Physiol Renal Physiol 2016; 311:F682-F685. [PMID: 27440780 DOI: 10.1152/ajprenal.00373.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 07/13/2016] [Indexed: 01/11/2023] Open
Abstract
Recent evidence indicates the adaptor protein SH2B3 has a major role in the progression of renal diseases. SH2B3 is highly expressed by hematopoietic cells and regulates cytokine signaling, inducing cell-specific effects. Additionally, its expression in other cell types suggests that SH2B3 may have a more extensive role within the kidney. Ex vivo studies have determined targets of SH2B3 cell-specific signaling, while in vivo studies have observed the SH2B3 overall affects in the progression of renal diseases. This mini-review covers the function of SH2B3-expressing cell types that contribute to renal pathologies and their regulation by SH2B3.
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Affiliation(s)
- Gregory Blass
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - David L Mattson
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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Velazquez L. The Lnk adaptor protein: a key regulator of normal and pathological hematopoiesis. Arch Immunol Ther Exp (Warsz) 2012; 60:415-29. [PMID: 22990499 DOI: 10.1007/s00005-012-0194-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 08/06/2012] [Indexed: 01/24/2023]
Abstract
The development and function of blood cells are regulated by specific growth factors/cytokines and their receptors' signaling pathways. In this way, these factors influence cell survival, proliferation and differentiation of hematopoietic cells. Central to this positive and/or negative control are the adaptor proteins. Since their identification 10 years ago, members of the Lnk adaptor protein family have proved to be important activators and/or inhibitors in the hematopoietic, immune and vascular system. In particular, the generation of animal and cellular models for the Lnk and APS proteins has helped establish the physiological role of these molecules through the identification of their specific signaling pathways and the characterization of their binding partners. Moreover, the recent identification of mutations in the LNK gene in myeloproliferative disorders, as well as the correlation of a single nucleotide polymorphism on LNK with hematological, immune and vascular diseases have suggested its involvement in the pathophysiology of these malignancies. The latter findings have thus raised the possibility of addressing Lnk signaling for the treatment of certain human diseases. This review therefore describes the pathophysiological role of this adaptor protein in hematological malignancies and the potential benefits of Lnk therapeutic targeting.
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Affiliation(s)
- Laura Velazquez
- UMR U978 Inserm/Université Paris 13, UFR SMBH, Bobigny, France.
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Devallière J, Chatelais M, Fitau J, Gérard N, Hulin P, Velazquez L, Turner CE, Charreau B. LNK (SH2B3) is a key regulator of integrin signaling in endothelial cells and targets α-parvin to control cell adhesion and migration. FASEB J 2012; 26:2592-606. [PMID: 22441983 DOI: 10.1096/fj.11-193383] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Focal adhesion (FA) formation and disassembly play an essential role in adherence and migration of endothelial cells. These processes are highly regulated and involve various signaling molecules that are not yet completely identified. Lnk [Src homology 2-B3 (SH2B3)] belongs to a family of SH2-containing proteins with important adaptor functions. In this study, we showed that Lnk distribution follows that of vinculin, localizing Lnk in FAs. Inhibition of Lnk by RNA interference resulted in decreased spreading, whereas sustained expression dramatically increases the number of focal and cell-matrix adhesions. We demonstrated that Lnk expression impairs FA turnover and cell migration and regulates β1-integrin-mediated signaling via Akt and GSK3β phosphorylation. Moreover, the α-parvin protein was identified as one of the molecular targets of Lnk responsible for impaired FA dynamics and cell migration. Finally, we established the ILK protein as a new molecular partner for Lnk and proposed a model in which Lnk regulates α-parvin expression through its interaction with ILK. Collectively, our results underline the adaptor Lnk as a novel and effective key regulator of integrin-mediated signaling controlling endothelial cell adhesion and migration.
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Affiliation(s)
- Julie Devallière
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 643, Nantes, France
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Devallière J, Charreau B. The adaptor Lnk (SH2B3): an emerging regulator in vascular cells and a link between immune and inflammatory signaling. Biochem Pharmacol 2011; 82:1391-402. [PMID: 21723852 DOI: 10.1016/j.bcp.2011.06.023] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 12/20/2022]
Abstract
A better knowledge of the process by which inflammatory extracellular signals are relayed from the plasma membrane to specific intracellular sites is a key step to understand how inflammation develops and how it is regulated. This review focuses on Lnk (SH2B3) a member, with SH2B1 and SH2B2, of the SH2B family of adaptor proteins that influences a variety of signaling pathways mediated by Janus kinase and receptor tyrosine kinases. SH2B adaptor proteins contain conserved dimerization, pleckstrin homology, and SH2 domains. Initially described as a regulator of hematopoiesis and lymphocyte differentiation, Lnk now emerges as a key regulator in hematopoeitic and non hematopoeitic cells such as endothelial cells (EC) moderating growth factor and cytokine receptor-mediated signaling. In EC, Lnk is a negative regulator of TNF signaling that reduce proinflammatory phenotype and prevent EC from apoptosis. Lnk is a modulator in integrin signaling and actin cytoskeleton organization in both platelets and EC with an impact on cell adhesion, migration and thrombosis. In this review, we discuss some recent insights proposing Lnk as a key regulator of bone marrow-endothelial progenitor cell kinetics, including the ability to cell growth, endothelial commitment, mobilization, and recruitment for vascular regeneration. Finally, novel findings also provided evidences that mutations in Lnk gene are strongly linked to myeloproliferative disorders but also autoimmune and inflammatory syndromes where both immune and vascular cells display a role. Overall, these studies emphasize the importance of the Lnk adaptor molecule not only as prognostic marker but also as potential therapeutic target.
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Chatelais M, Devallière J, Galli C, Charreau B. Gene transfer of the adaptor Lnk (SH2B3) prevents porcine endothelial cell activation and apoptosis: implication for xenograft’s cytoprotection. Xenotransplantation 2011; 18:108-20. [DOI: 10.1111/j.1399-3089.2011.00629.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Quillard T, Devallière J, Coupel S, Charreau B. Inflammation dysregulates Notch signaling in endothelial cells: implication of Notch2 and Notch4 to endothelial dysfunction. Biochem Pharmacol 2010; 80:2032-41. [PMID: 20643108 DOI: 10.1016/j.bcp.2010.07.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 07/02/2010] [Accepted: 07/08/2010] [Indexed: 12/30/2022]
Abstract
Although the involvement of the Notch pathway in several areas of vascular biology is now clearly established, its role in vascular inflammation at the endothelial level remains to be elucidated. In this study, we demonstrated that pro-inflammatory cytokines drive a specific regulation of the Notch pathway in vascular endothelial cells (ECs). In arterial ECs, TNFα strongly modulates the pattern of Notch expression by decreasing Notch4 expression while increasing Notch2 expression. Changes in Notch expression were associated with a reduction in hes1 and hey2 expression and in CBF1 reporter gene activity, suggesting that TNFα regulates both Notch expression and activity. Notch2 and Notch4 regulations occurred independently and were found to be mostly mediated by the NFκB signaling pathways and PI3-kinase signaling pathways, respectively. Functionally, TNF-mediated Notch regulation promotes caspase-dependent EC apoptosis. Finally, our findings confirmed that dysregulated Notch signaling also occurs upon inflammation in vivo and correlates with caspase activation and apoptosis. In conclusion, inflammatory cytokines elicit a switch in Notch expression characterized by Notch2 predominance over Notch4 leading to a reduced Notch activity and promoting apoptosis. Thus, here we provide evidence for a role of soluble mediators of inflammation (i.e. cytokines) in the regulation of Notch signaling and for the implication of a dysregulated Notch pathway to endothelial and vascular dysfunction.
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Gueller S, Goodridge HS, Niebuhr B, Xing H, Koren-Michowitz M, Serve H, Underhill DM, Brandts CH, Koeffler HP. Adaptor protein Lnk inhibits c-Fms-mediated macrophage function. J Leukoc Biol 2010; 88:699-706. [PMID: 20571037 DOI: 10.1189/jlb.0309185] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The M-CSFR (c-Fms) participates in proliferation, differentiation, and survival of macrophages and is involved in the regulation of distinct macrophage functions. Interaction with the ligand M-CSF results in phosphorylation of tyrosine residues on c-Fms, thereby creating binding sites for molecules containing SH2 domains. Lnk is a SH2 domain adaptor protein that negatively regulates hematopoietic cytokine receptors. Here, we show that Lnk binds to c-Fms. Biological and functional effects of this interaction were examined in macrophages from Lnk-deficient (KO) and WT mice. Clonogenic assays demonstrated an elevated number of M-CFUs in the bone marrow of Lnk KO mice. Furthermore, the M-CSF-induced phosphorylation of Akt in Lnk KO macrophages was increased and prolonged, whereas phosphorylation of Erk was diminished. Zymosan-stimulated production of ROS was increased dramatically in a M-CSF-dependent manner in Lnk KO macrophages. Lastly, Lnk inhibited M-CSF-induced migration of macrophages. In summary, we show that Lnk binds to c-Fms and can blunt M-CSF stimulation. Modulation of levels of Lnk in macrophages may provide a unique therapeutic approach to increase innate host defenses.
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Affiliation(s)
- Saskia Gueller
- Department of Hematology and Oncology, Johann Wolfgang Goethe University, Frankfurt, Germany.
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Wan M, Li Y, Xue H, Li Q, Li J. Eicosapentaenoic acid inhibits TNF-α-induced Lnk expression in human umbilical vein endothelial cells: involvement of the PI3K/Akt pathway. J Nutr Biochem 2007; 18:17-22. [PMID: 16784840 DOI: 10.1016/j.jnutbio.2006.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Revised: 02/04/2006] [Accepted: 02/06/2006] [Indexed: 10/24/2022]
Abstract
n-3 Polyunsaturated fatty acids (PUFAs) exert anti-inflammatory properties by influencing inflammatory cell activation processes. Lnk is an adaptor protein involving endothelial cell (EC) activation because it is induced by tumor necrosis factor-alpha (TNF-alpha). This study was conducted to evaluate the role of eicosapentaenoic acid (EPA), an n-3 PUFA, in the regulation of Lnk expression in human umbilical vein endothelial cells (HUVECs). Primary HUVECs were pretreated with EPA for 12 h at various concentrations (0-40 muM) and then exposed for another 12 h in the presence or absence of TNF-alpha (10 ng/ml). Lnk mRNA and protein were detected using reverse transcriptase polymerase chain reaction, immunoprecipitation and Western blot analysis. Results showed that pretreatment of HUVEC with EPA inhibited TNF-alpha-induced expression of Lnk in a dose-dependent manner. TNF-alpha-induced Lnk was also inhibited by a phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002. Thus, we investigated the role of PI3K/Akt signaling pathway in this process. Phosphorylation of Akt was assessed by Western blot analysis. We found that EPA treatment decreased the amount of activated Akt. These results showed that EPA inhibited TNF-alpha-induced Lnk expression in HUVECs through the PI3K/Akt pathway. This may be a potential mechanism by which EPA protects ECs under inflammatory conditions.
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Affiliation(s)
- Meifang Wan
- Nanjing University School of Medicine, Nanjing 210093, P.R. China
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Wan M, Li Y, Xue H, Li Q, Li J. TNF-alpha induces Lnk expression through PI3K-dependent signaling pathway in human umbilical vein endothelial cells. J Surg Res 2006; 136:53-7. [PMID: 17007883 DOI: 10.1016/j.jss.2006.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 06/30/2006] [Accepted: 07/05/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND A better understanding of activation process of endothelial cells (ECs) might reveal new ways of controlling inflammation. Adaptor proteins play crucial roles in ECs activation. Lnk is a newly discovered adaptor protein that has been proposed as a negative regulator of cytokine signaling. While limited information is available about Lnk in human ECs. This study was conducted to investigate the effect of TNF-alpha on Lnk expression in ECs and to identify the signal transduction pathway that is associated with Lnk regulation. MATERIALS AND METHODS Primary human umbilical vein endothelial cells (HUVECs) were cultured with designated doses of TNF-alpha and harvested at designated time points. Then Lnk mRNA and protein were detected using real-time polymerase chain reaction, immunoprecipitation and Western blot analysis, respectively. RESULTS The data demonstrated that Lnk mRNA and protein expression are induced significantly (P < 0.05) by TNF-alpha in a dose- and time-dependent manner. This inductive effect was abolished while phosphatidylinositol 3-kinase (PI3K) pathway was blocked by the PI3K inhibitor LY294002 and Wortmannin. CONCLUSION These results suggest that TNF-alpha induces Lnk expression through PI3K-dependent signaling pathway in HUVEC. This may indicate a role for this new adaptor protein in the regulation of TNF-alpha-induced ECs activation.
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Affiliation(s)
- Meifang Wan
- Nanjing University School of Medicine, Nanjing, China
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Fitau J, Boulday G, Coulon F, Quillard T, Charreau B. The adaptor molecule Lnk negatively regulates tumor necrosis factor-alpha-dependent VCAM-1 expression in endothelial cells through inhibition of the ERK1 and -2 pathways. J Biol Chem 2006; 281:20148-59. [PMID: 16644735 DOI: 10.1074/jbc.m510997200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Lnk, with APS and SH2-B (Src homology 2-B), belongs to a family of SH2-containing proteins with potential adaptor functions. Lnk regulates growth factor and cytokine receptor-mediated pathways implicated in lymphoid, myeloid, and platelet homeostasis. We have previously shown that Lnk is expressed and up-regulated in vascular endothelial cells (ECs) in response to tumor necrosis factor-alpha (TNFalpha). In this study, we have shown that, in ECs, Lnk down-regulates the expression, at both mRNA and protein levels, of the proinflammatory molecules VCAM-1 and E-selectin induced by TNFalpha. Mechanistically, our data indicated that, in response to TNFalpha, NFkappaB/p65 phosphorylation and translocation as well as IkappaBalpha phosphorylation and degradation were unchanged, suggesting that Lnk does not modulate NFkappaB activity. However, Lnk activates phosphatidylinositol 3-kinase (PI3K) as reflected by Akt phosphorylation. Our results identify endothelial nitric-oxide synthase as a downstream target of Lnk-mediated activation of the PI3K/Akt pathway and HO-1 as a new substrate of Akt. We found that sustained Lnk-mediated activation of PI3K in TNFalpha-activated ECs correlated with the inhibition of ERK1/2 phosphorylation, whereas phosphorylation of p38 and c-Jun NH(2)-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs) was unchanged. ERK1/2 inhibition decreases VCAM-1 expression in TNFalpha-treated ECs. Collectively, our results identify the adaptor Lnk as a negative regulator in the TNFalpha-signaling pathway mediating ERK inhibition and suggest a role for Lnk in the interplay between PI3K and ERK triggered by TNFalpha in ECs.
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Fitau J, Boulday G, Coulon F, Charreau B. La protéine adaptatrice Lnk module l'activation des cellules endothéliales. Nephrol Ther 2005; 1:228-33. [PMID: 16895689 DOI: 10.1016/j.nephro.2005.06.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Revised: 06/13/2005] [Accepted: 06/20/2005] [Indexed: 11/19/2022]
Abstract
Lnk is an adaptator protein involved in B lymphocytes and platelet differentiation and in T lymphocyte activation. We previously reported on Lnk expression and regulation in endothelial cells (ECs) upon activation. In the present study, the involvement of Lnk in the tumor necrosis factor alpha (TNFalpha) pathway was investigated in vitro through Lnk overexpression in primary cultures of human endothelial cells. Using a recombinant adenovirus encoding human Lnk, we first demonstrated that Lnk overexpression does not induce vascular cell adhesion molecule-1 (VCAM-1) suggesting that Lnk does not promote ECs activation. However, Lnk overexpression significantly reduced TNFalpha-mediated expression of VCAM-1 (at mRNA and protein levels) in activated EC as compared with controls. Western blot analysis showed that Lnk overexpression in HUVEC was associated with phosphorylation of Akt kinase (at Ser 473) with no effect on IkappaBalpha, the specific inhibitor of NFkappaB, indicating that Lnk promotes activation of the phosphatidylinositol 3-kinase (PI3-kinase) pathway in ECs. Altogether, these results suggest that, in ECs, Lnk may participate to a regulatory pathway involving the PI3-kinase and modulating the inflammatory response.
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Affiliation(s)
- Juliette Fitau
- Institut national de la santé et de la recherche médicale, UMR 643, Immunointervention en allo et xénotransplantation, et institut de transplantation et de recherche en transplantation, CHU Hôtel-Dieu, 44093 Nantes cedex 01, France
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