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Jo G, Bae J, Hong HJ, Han AR, Kim DK, Hong SP, Kim JA, Lee S, Koh GY, Kim HM. Structural insights into the clustering and activation of Tie2 receptor mediated by Tie2 agonistic antibody. Nat Commun 2021; 12:6287. [PMID: 34725372 PMCID: PMC8560823 DOI: 10.1038/s41467-021-26620-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 10/15/2021] [Indexed: 01/09/2023] Open
Abstract
Angiopoietin (Angpt)-Tie receptor 2 (Tie2) plays key roles in vascular development and homeostasis as well as pathological vascular remodeling. Therefore, Tie2-agonistic antibody and engineered Angpt1 variants have been developed as potential therapeutics for ischemic and inflammatory vascular diseases. However, their underlying mechanisms for Tie2 clustering and activation remain elusive and the poor manufacturability and stability of Angpt1 variants limit their clinical application. Here, we develop a human Tie2-agonistic antibody (hTAAB), which targets the membrane proximal fibronectin type III domain of Tie2 distinct from the Angpt-binding site. Our Tie2/hTAAB complex structures reveal that hTAAB tethers the preformed Tie2 homodimers into polygonal assemblies through specific binding to Tie2 Fn3 domain. Notably, the polygonal Tie2 clustering induced by hTAAB is critical for Tie2 activation and are resistant to antagonism by Angpt2. Our results provide insight into the molecular mechanism of Tie2 clustering and activation mediated by hTAAB, and the structure-based humanization of hTAAB creates a potential clinical application.
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Affiliation(s)
- Gyunghee Jo
- grid.37172.300000 0001 2292 0500Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea ,grid.410720.00000 0004 1784 4496Center for Biomolecular & Cellular Structure, Institute for Basic Science (IBS), Daejeon, 34126 Republic of Korea
| | - Jeomil Bae
- grid.410720.00000 0004 1784 4496Center for Vascular Research, IBS, Daejeon, 34141 Republic of Korea
| | - Ho Jeong Hong
- grid.410720.00000 0004 1784 4496Center for Biomolecular & Cellular Structure, Institute for Basic Science (IBS), Daejeon, 34126 Republic of Korea
| | - Ah-reum Han
- grid.410720.00000 0004 1784 4496Center for Biomolecular & Cellular Structure, Institute for Basic Science (IBS), Daejeon, 34126 Republic of Korea
| | - Do-Kyun Kim
- grid.410720.00000 0004 1784 4496Center for Biomolecular & Cellular Structure, Institute for Basic Science (IBS), Daejeon, 34126 Republic of Korea
| | - Seon Pyo Hong
- grid.410720.00000 0004 1784 4496Center for Vascular Research, IBS, Daejeon, 34141 Republic of Korea
| | - Jung A Kim
- grid.37172.300000 0001 2292 0500Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea
| | - Sangkyu Lee
- grid.410720.00000 0004 1784 4496Center for Cognition and Sociality, IBS, Daejeon, 34126 Republic of Korea
| | - Gou Young Koh
- grid.37172.300000 0001 2292 0500Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea ,grid.410720.00000 0004 1784 4496Center for Vascular Research, IBS, Daejeon, 34141 Republic of Korea
| | - Ho Min Kim
- grid.37172.300000 0001 2292 0500Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 Republic of Korea ,grid.410720.00000 0004 1784 4496Center for Biomolecular & Cellular Structure, Institute for Basic Science (IBS), Daejeon, 34126 Republic of Korea
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2
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Sudhadevi T, Jafri A, Ha AW, Basa P, Thomas JM, Fu P, Wary K, Mehta D, Natarajan V, Harijith A. Hyperoxia-induced S1P 1 signaling reduced angiogenesis by suppression of TIE-2 leading to experimental bronchopulmonary dysplasia. Cell Biochem Biophys 2021; 79:561-573. [PMID: 34176100 DOI: 10.1007/s12013-021-01014-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2021] [Indexed: 01/16/2023]
Abstract
INTRODUCTION We have earlier shown that hyperoxia (HO)-induced sphingosine kinase 1 (SPHK1)/sphingosine-1-phosphate (S1P) signaling contribute to bronchopulmonary dysplasia (BPD). S1P acts through G protein-coupled receptors, S1P1 through S1P5. Further, we noted that heterozygous deletion of S1pr1 ameliorated the HO-induced BPD in the murine model. The mechanism by which S1P1 signaling contributes to HO-induced BPD was explored. METHODS S1pr1+/+ and S1pr1+/- mice pups were exposed to either room air (RA) or HO (75% oxygen) for 7 days from PN 1-7. Lung injury and alveolar simplification was evaluated. Lung protein expression was determined by Western blotting and immunohistochemistry (IHC). In vitro experiments were performed using human lung microvascular endothelial cells (HLMVECs) with S1P1 inhibitor, NIBR0213 to interrogate the S1P1 signaling pathway. RESULTS HO increased the expression of S1pr1 gene as well as S1P1 protein in both neonatal lungs and HLMVECs. The S1pr1+/- neonatal mice showed significant protection against HO-induced BPD which was accompanied by reduced inflammation markers in the bronchoalveolar lavage fluid. HO-induced reduction in ANG-1, TIE-2, and VEGF was rescued in S1pr1+/- mouse, accompanied by an improvement in the number of arterioles in the lung. HLMVECs exposed to HO increased the expression of KLF-2 accompanied by reduced expression of TIE-2, which was reversed with S1P1 inhibition. CONCLUSION HO induces S1P1 followed by reduced expression of angiogenic factors. Reduction of S1P1 signaling restores ANG-1/ TIE-2 signaling leading to improved angiogenesis and alveolarization thus protecting against HO-induced neonatal lung injury.
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Affiliation(s)
- Tara Sudhadevi
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Anjum Jafri
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Alison W Ha
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Prathima Basa
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Jaya M Thomas
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Panfeng Fu
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Kishore Wary
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Dolly Mehta
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Viswanathan Natarajan
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Anantha Harijith
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA.
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Issa E, Moss AJ, Fischer M, Kang M, Ahmed S, Farah H, Bate N, Giakomidi D, Brindle NP. Development of an Orthogonal Tie2 Ligand Resistant to Inhibition by Ang2. Mol Pharm 2018; 15:3962-3968. [PMID: 30036484 DOI: 10.1021/acs.molpharmaceut.8b00409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Angiopoietin-1 (Ang1) is a vascular protective ligand that acts through the receptor tyrosine kinase Tie2 to enhance endothelial survival and quiescence. In sepsis, diabetic retinopathy, and a range of other diseases, Ang2, an antagonist of Tie2, increases markedly. This antagonist suppresses Ang1 protective effects leading to vascular destabilization, inflammation, and endothelial death. Administration of recombinant Ang1 can counter Ang2 antagonism and restore vascular function. However, recombinant Ang1 is needed at sufficiently high concentrations to block Ang2, and the protein is difficult to produce, requires mammalian expression systems, and is prone to aggregation. Here we present an engineered synthetic Tie2 ligand that is not antagonized by Ang2 but is easy to produce and more robust than Ang1. Using a peptide phage display, we isolated a heptameric sequence that binds Tie2-ectodomain and fused this to the coiled:coil domain of cartilage oligomeric matrix protein. This pentameric protein is 60 kDa in size, expressed in E. coli, and facile to purify. The protein, designated TSL1, binds to Tie2-ectodomain in vitro and on the cell surface. TSL1 inhibits endothelial apoptosis. Crucially, TSL1 binds at a site on Tie2 distinct from the angiopoietin-binding site and is resistant to antagonism by Ang2. This engineered ligand has several advantages over recombinant Ang1 for potential therapeutic applications. The study also highlights the value of orthogonal ligands for regulating cellular receptors without being subject to antagonism or modulation by endogenous ligands.
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Affiliation(s)
- Eyad Issa
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
| | - Andrew J Moss
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
| | - Marlies Fischer
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
| | - Mandeep Kang
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
| | - Sultan Ahmed
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
| | - Hussein Farah
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
| | - Neil Bate
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
| | - Despoina Giakomidi
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
| | - Nicholas Pj Brindle
- Department of Cardiovascular Sciences and Department of Molecular and Cell Biology , University of Leicester , Henry Wellcome Building, Lancaster Road , Leicester LE1 7RH , U.K
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Review of the endothelial pathogenic mechanism of TIE2-related venous malformation. J Vasc Surg Venous Lymphat Disord 2017; 5:740-748. [DOI: 10.1016/j.jvsv.2017.05.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 03/11/2017] [Indexed: 11/20/2022]
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Sarabipour S. Parallels and Distinctions in FGFR, VEGFR, and EGFR Mechanisms of Transmembrane Signaling. Biochemistry 2017. [DOI: 10.1021/acs.biochem.7b00399] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Sarvenaz Sarabipour
- Institute for Computational
Medicine and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Wang S, Wang X, Boone J, Wie J, Yip KP, Zhang J, Wang L, Liu R. Application of Hanging Drop Technique for Kidney Tissue Culture. Kidney Blood Press Res 2017; 42:220-231. [PMID: 28478441 PMCID: PMC6050513 DOI: 10.1159/000476018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 02/07/2017] [Indexed: 12/13/2022] Open
Abstract
Background/Aims The hanging drop technique is a well-established method used in culture of animal tissues. However, this method has not been used in adult kidney tissue culture yet. This study was to explore the feasibility of using this technique for culturing adult kidney cortex to study the time course of RNA viability in the tubules and vasculature, as well as the tissue structural integrity. Methods In each Petri dish with the plate covered with sterile buffer, a section of mouse renal cortex was cultured within a drop of DMEM culture medium on the inner surface of the lip facing downward. The tissue were then harvested at each specific time points for Real-time PCR analysis and histological studies. Results The results showed that the mRNA level of most Na+ related transporters and cotransporters were stably maintained within 6 hours in culture, and that the mRNA level of most receptors found in the vasculature and glomeruli were stably maintained for up to 9 days in culture. Paraffin sections of the cultured renal cortex indicated that the tubules began to lose tubular integrity after 6 hours, but the glomeruli and vasculatures were still recognizable up to 9 days in culture. Conclusions We concluded that adult kidney tissue culture by hanging drop method can be used to study gene expressions in vasculature and glomeruli.
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Affiliation(s)
- Shaohui Wang
- Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Ximing Wang
- Present Address: Shandong Medical Imaging Research Institute, Shandong provincial key laboratory of diagnosis and treatment of cardio-cerebral vascular disease, Shandong University, Jinan, China
| | - Jasmine Boone
- Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Jin Wie
- Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Kay-Pong Yip
- Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Jie Zhang
- Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Lei Wang
- Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
| | - Ruisheng Liu
- Department of Molecular Pharmacology & Physiology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA
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Abstract
Tie1 and Tie2, members of the tyrosine kinase family with immunoglobulin and EGF homology domains, are receptor tyrosine kinases found primarily in endothelial cells with key roles in development and maintenance of the vasculature and in angiogenesis. They are attractive targets for therapeutic intervention in tumor angiogenesis, inflammation, and sepsis. Tie2 is regulated directly by the multimeric angiopoietin (Ang) ligands, with Ang1 being its primary activator. Structural studies have shown how Angs bind to the Tie2 ligand-binding region, but do not explain Tie2 activation and suggest a passive role for the Tie2 extracellular region (ECR) in ligand-induced receptor dimerization. Here we show that the Tie2 ECR forms strong dimers even in the absence of bound ligand. Dimerization is mediated by membrane-proximal fibronectin type III (FNIII) domains that were omitted in previous structural studies. We describe a 2.5-Å resolution X-ray crystal structure of the membrane-proximal three Tie2 FNIII domains, Tie2(FNIIIa-c), revealing two possible dimerization modes that primarily involve the third FNIII domain, FNIIIc. Mutating these dimer interfaces implicates one of them (dimer 1) in soluble Tie2 (sTie2) dimerization in solution but suggests that both could play a role in Ang1-induced Tie2 activation, possibly modulated by Tie1. Through small-angle X-ray scattering studies of sTie2 dimers in solution and modeling based on crystal structures, we suggest that Ang1 binding may cross-link Tie2 dimers into higher-order oligomers, potentially explaining how Tie2 is differentially clustered following ligand engagement in different cellular contexts. Our results also firmly implicate FNIII domain-mediated interactions in Tie2 activation, identifying a potential Achilles' heel for therapeutic inhibition.
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8
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Kanemaru K, Noguchi E, Tokunaga T, Nagai K, Hiroyama T, Nakamura Y, Tahara-Hanaoka S, Shibuya A. Tie2 Signaling Enhances Mast Cell Progenitor Adhesion to Vascular Cell Adhesion Molecule-1 (VCAM-1) through α4β1 Integrin. PLoS One 2015; 10:e0144436. [PMID: 26659448 PMCID: PMC4687632 DOI: 10.1371/journal.pone.0144436] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/18/2015] [Indexed: 12/21/2022] Open
Abstract
Mast cell (MC) activation contributes considerably to immune responses, such as host protection and allergy. Cell surface immunoreceptors expressed on MCs play an important role in MC activation. Although various immunoreceptors on MCs have been identified, the regulatory mechanism of MC activation is not fully understood. To understand the regulatory mechanisms of MC activation, we used gene expression analyses of human and mouse MCs to identify a novel immunoreceptor expressed on MCs. We found that Tek, which encodes Tie2, was preferentially expressed in the MCs of both humans and mice. However, Tie2 was not detected on the cell surface of the mouse MCs of the peritoneal cavity, ear skin, or colon lamina propria. In contrast, it was expressed on mouse bone marrow–derived MCs and bone marrow MC progenitors (BM-MCps). Stimulation of Tie2 by its ligand angiopoietin-1 induced tyrosine phosphorylation of Tie2 in MEDMC-BRC6, a mouse embryonic stem cell-derived mast cell line, and enhanced MEDMC-BRC6 and mouse BM-MCp adhesion to vascular cell adhesion molecule-1 (VCAM-1) through α4β1 integrin. These results suggest that Tie2 signaling induces α4β1 integrin activation on BM-MCps for adhesion to VCAM-1.
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Affiliation(s)
- Kazumasa Kanemaru
- Department of Immunology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Emiko Noguchi
- Department of Medical Genetics, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Takahiro Tokunaga
- Department of Medical Genetics, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Department of Otorhinolaryngology Head and Neck Surgery, University of Fukui, Fukui, Japan
| | - Kei Nagai
- Department of Immunology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takashi Hiroyama
- Cell Engineering Division, RIKEN BioResource Center, Kounodai, Tsukuba, Ibaraki, Japan
| | - Yukio Nakamura
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Cell Engineering Division, RIKEN BioResource Center, Kounodai, Tsukuba, Ibaraki, Japan
| | - Satoko Tahara-Hanaoka
- Department of Immunology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, Japan
- Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
| | - Akira Shibuya
- Department of Immunology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, Japan
- Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo, Japan
- * E-mail:
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Classification and Tie2 mutations in spinal and soft tissue vascular anomalies. Gene 2015; 571:91-6. [DOI: 10.1016/j.gene.2015.06.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/09/2015] [Accepted: 06/19/2015] [Indexed: 11/24/2022]
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Nätynki M, Kangas J, Miinalainen I, Sormunen R, Pietilä R, Soblet J, Boon LM, Vikkula M, Limaye N, Eklund L. Common and specific effects of TIE2 mutations causing venous malformations. Hum Mol Genet 2015; 24:6374-89. [PMID: 26319232 DOI: 10.1093/hmg/ddv349] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 08/24/2015] [Indexed: 01/09/2023] Open
Abstract
Venous malformations (VMs) are localized defects in vascular morphogenesis frequently caused by mutations in the gene for the endothelial tyrosine kinase receptor TIE2. Here, we report the analysis of a comprehensive collection of 22 TIE2 mutations identified in patients with VM, either as single amino acid substitutions or as double-mutations on the same allele. Using endothelial cell (EC) cultures, mouse models and ultrastructural analysis of tissue biopsies from patients, we demonstrate common as well as mutation-specific cellular and molecular features, on the basis of which mutations cluster into categories that correlate with data from genetic studies. Comparisons of double-mutants with their constituent single-mutant forms identified the pathogenic contributions of individual changes, and their compound effects. We find that defective receptor trafficking and subcellular localization of different TIE2 mutant forms occur via a variety of mechanisms, resulting in attenuated response to ligand. We also demonstrate, for the first time, that TIE2 mutations cause chronic activation of the MAPK pathway resulting in loss of normal EC monolayer due to extracellular matrix (ECM) fibronectin deficiency and leading to upregulation of plasminogen/plasmin proteolytic pathway. Corresponding EC and ECM irregularities are observed in affected tissues from mouse models and patients. Importantly, an imbalance between plasminogen activators versus inhibitors would also account for high d-dimer levels, a major feature of unknown cause that distinguishes VMs from other vascular anomalies.
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Affiliation(s)
- Marjut Nätynki
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Jaakko Kangas
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | | | - Raija Sormunen
- Biocenter Oulu, University of Oulu, Oulu, Finland, Department of Pathology and Oulu University Hospital, University of Oulu, Oulu, Finland
| | - Riikka Pietilä
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Julie Soblet
- Human Molecular Genetics, de Duve Institute, and
| | - Laurence M Boon
- Human Molecular Genetics, de Duve Institute, and Center for Vascular Anomalies, Division of Plastic Surgery, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | | | - Nisha Limaye
- Human Molecular Genetics, de Duve Institute, and
| | - Lauri Eklund
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland,
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Emerging concepts in the regulation of the EGF receptor and other receptor tyrosine kinases. Trends Biochem Sci 2014; 39:437-46. [DOI: 10.1016/j.tibs.2014.08.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/04/2014] [Accepted: 08/07/2014] [Indexed: 11/21/2022]
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Abstract
Dynamic changes in microvascular endothelial structure and function are pivotal in the acute inflammatory response, the body's rapid, coordinated effort to localize, sequester, and eliminate microbial invaders at their portal of entry. To achieve this, the endothelium becomes leaky and inflamed, providing innate immune cells and humoral effector molecules access to the site of infection. During sepsis this locally adaptive response becomes manifest throughout the body, leading to dangerous host consequences. Increased leakiness in the pulmonary circulation contributes to acute respiratory distress syndrome (ARDS), a complication of sepsis associated with 40% mortality. Understanding the molecular governance of vascular leak and inflammation has major diagnostic, prognostic, and potentially therapeutic implications for this common and pernicious disease. This review summarizes results from cell-based experiments, animal models, and observational human studies; together, these studies suggest that an endothelial receptor called Tie2 and its ligands, called angiopoietins, form a signaling axis key to the vascular dyshomeostasis that underlies sepsis.
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