1
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Dasetty S, Bidone TC, Ferguson AL. Data-driven prediction of α IIbβ 3 integrin activation paths using manifold learning and deep generative modeling. Biophys J 2024; 123:2716-2729. [PMID: 38098231 PMCID: PMC11393677 DOI: 10.1016/j.bpj.2023.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 01/06/2024] Open
Abstract
The integrin heterodimer is a transmembrane protein critical for driving cellular process and is a therapeutic target in the treatment of multiple diseases linked to its malfunction. Activation of integrin involves conformational transitions between bent and extended states. Some of the conformations that are intermediate between bent and extended states of the heterodimer have been experimentally characterized, but the full activation pathways remain unresolved both experimentally due to their transient nature and computationally due to the challenges in simulating rare barrier crossing events in these large molecular systems. An understanding of the activation pathways can provide new fundamental understanding of the biophysical processes associated with the dynamic interconversions between bent and extended states and can unveil new putative therapeutic targets. In this work, we apply nonlinear manifold learning to coarse-grained molecular dynamics simulations of bent, extended, and two intermediate states of αIIbβ3 integrin to learn a low-dimensional embedding of the configurational phase space. We then train deep generative models to learn an inverse mapping between the low-dimensional embedding and high-dimensional molecular space and use these models to interpolate the molecular configurations constituting the activation pathways between the experimentally characterized states. This work furnishes plausible predictions of integrin activation pathways and reports a generic and transferable multiscale technique to predict transition pathways for biomolecular systems.
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Affiliation(s)
- Siva Dasetty
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois
| | - Tamara C Bidone
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah
| | - Andrew L Ferguson
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois.
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2
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Li S, Sampson C, Liu C, Piao HL, Liu HX. Integrin signaling in cancer: bidirectional mechanisms and therapeutic opportunities. Cell Commun Signal 2023; 21:266. [PMID: 37770930 PMCID: PMC10537162 DOI: 10.1186/s12964-023-01264-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/09/2023] [Indexed: 09/30/2023] Open
Abstract
Integrins are transmembrane receptors that possess distinct ligand-binding specificities in the extracellular domain and signaling properties in the cytoplasmic domain. While most integrins have a short cytoplasmic tail, integrin β4 has a long cytoplasmic tail that can indirectly interact with the actin cytoskeleton. Additionally, 'inside-out' signals can induce integrins to adopt a high-affinity extended conformation for their appropriate ligands. These properties enable integrins to transmit bidirectional cellular signals, making it a critical regulator of various biological processes.Integrin expression and function are tightly linked to various aspects of tumor progression, including initiation, angiogenesis, cell motility, invasion, and metastasis. Certain integrins have been shown to drive tumorigenesis or amplify oncogenic signals by interacting with corresponding receptors, while others have marginal or even suppressive effects. Additionally, different α/β subtypes of integrins can exhibit opposite effects. Integrin-mediated signaling pathways including Ras- and Rho-GTPase, TGFβ, Hippo, Wnt, Notch, and sonic hedgehog (Shh) are involved in various stages of tumorigenesis. Therefore, understanding the complex regulatory mechanisms and molecular specificities of integrins are crucial to delaying cancer progression and suppressing tumorigenesis. Furthermore, the development of integrin-based therapeutics for cancer are of great importance.This review provides an overview of integrin-dependent bidirectional signaling mechanisms in cancer that can either support or oppose tumorigenesis by interacting with various signaling pathways. Finally, we focus on the future opportunities for emergent therapeutics based on integrin agonists. Video Abstract.
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Affiliation(s)
- Siyi Li
- Department of Thoracic Surgery, Cancer Research Institute, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang, 110042, China
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Chibuzo Sampson
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Changhao Liu
- Department of Thoracic Surgery, Cancer Research Institute, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang, 110042, China
| | - Hai-Long Piao
- Department of Thoracic Surgery, Cancer Research Institute, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang, 110042, China.
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
- Department of Biochemistry & Molecular Biology, School of Life Sciences, China Medical University, Shenyang, 110122, China.
| | - Hong-Xu Liu
- Department of Thoracic Surgery, Cancer Research Institute, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang, 110042, China.
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3
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Mancuso RV, Schneider G, Hürzeler M, Gut M, Zurflüh J, Breitenstein W, Bouitbir J, Reisen F, Atz K, Ehrhardt C, Duthaler U, Gygax D, Schmidt AG, Krähenbühl S, Weitz-Schmidt G. Allosteric targeting resolves limitations of earlier LFA-1 directed modalities. Biochem Pharmacol 2023; 211:115504. [PMID: 36921634 DOI: 10.1016/j.bcp.2023.115504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/16/2023]
Abstract
Integrins are a family of cell surface receptors well-recognized for their therapeutic potential in a wide range of diseases. However, the development of integrin targeting medications has been impacted by unexpected downstream effects, reflecting originally unforeseen interference with the bidirectional signalling and cross-communication of integrins. We here selected one of the most severely affected target integrins, the integrin lymphocyte function-associated antigen-1 (LFA-1, αLβ2, CD11a/CD18), as a prototypic integrin to systematically assess and overcome these known shortcomings. We employed a two-tiered ligand-based virtual screening approach to identify a novel class of allosteric small molecule inhibitors targeting this integrin's αI domain. The newly discovered chemical scaffold was derivatized, yielding potent bis-and tris-aryl-bicyclic-succinimides which inhibit LFA-1 in vitro at low nanomolar concentrations. The characterisation of these compounds in comparison to earlier LFA-1 targeting modalities established that the allosteric LFA-1 inhibitors (i) are devoid of partial agonism, (ii) selectively bind LFA-1 versus other integrins, (iii) do not trigger internalization of LFA-1 itself or other integrins and (iv) display oral availability. This profile differentiates the new generation of allosteric LFA-1 inhibitors from previous ligand mimetic-based LFA-1 inhibitors and anti-LFA-1 antibodies, and is projected to support novel immune regulatory regimens selectively targeting the integrin LFA-1. The rigorous computational and experimental assessment schedule described here is designed to be adaptable to the preclinical discovery and development of novel allosterically acting compounds targeting integrins other than LFA-1, providing an exemplary approach for the early characterisation of next generation integrin inhibitors.
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Affiliation(s)
- Riccardo V Mancuso
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, Basel, Switzerland; Molecular Pharmacy, Department of Pharmaceutical Sciences, University of Basel
| | - Gisbert Schneider
- ETH Zurich, Department of Chemistry and Applied Biosciences, Zurich, Switzerland; ETH Singapore SEC Ltd, Singapore
| | - Marianne Hürzeler
- School of Life Sciences FHNW, Institute for Chemistry and Bioanalytics, Muttenz, Switzerland
| | - Martin Gut
- School of Life Sciences FHNW, Institute for Chemistry and Bioanalytics, Muttenz, Switzerland
| | - Jonas Zurflüh
- School of Life Sciences FHNW, Institute for Chemistry and Bioanalytics, Muttenz, Switzerland
| | - Werner Breitenstein
- School of Life Sciences FHNW, Institute for Chemistry and Bioanalytics, Muttenz, Switzerland
| | - Jamal Bouitbir
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, Basel, Switzerland
| | - Felix Reisen
- ETH Zurich, Department of Chemistry and Applied Biosciences, Zurich, Switzerland; ETH Singapore SEC Ltd, Singapore
| | - Kenneth Atz
- ETH Zurich, Department of Chemistry and Applied Biosciences, Zurich, Switzerland; ETH Singapore SEC Ltd, Singapore
| | | | - Urs Duthaler
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, Basel, Switzerland
| | - Daniel Gygax
- School of Life Sciences FHNW, Institute for Chemistry and Bioanalytics, Muttenz, Switzerland
| | | | - Stephan Krähenbühl
- Division of Clinical Pharmacology & Toxicology, University Hospital Basel, Basel, Switzerland; Swiss Centre for Applied Human Toxicology (SCAHT), Basel, Switzerland
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4
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Hlophe YN, Joubert AM. Vascular endothelial growth
factor‐C
in activating vascular endothelial growth factor receptor‐3 and chemokine receptor‐4 in melanoma adhesion. J Cell Mol Med 2022; 26:5743-5754. [DOI: 10.1111/jcmm.17571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/27/2022] [Accepted: 09/12/2022] [Indexed: 11/19/2022] Open
Affiliation(s)
- Yvette N. Hlophe
- Department of Physiology University of Pretoria Pretoria South Africa
| | - Anna M. Joubert
- Department of Physiology University of Pretoria Pretoria South Africa
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5
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He WZ, Yang M, Jiang Y, He C, Sun YC, Liu L, Huang M, Jiao YR, Chen KX, Hou J, Huang M, Xu YL, Feng X, Liu Y, Guo Q, Peng H, Huang Y, Su T, Xiao Y, Li Y, Zeng C, Lei G, Luo XH, Li CJ. miR-188-3p targets skeletal endothelium coupling of angiogenesis and osteogenesis during ageing. Cell Death Dis 2022; 13:494. [PMID: 35610206 PMCID: PMC9130327 DOI: 10.1038/s41419-022-04902-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 04/26/2022] [Accepted: 04/29/2022] [Indexed: 12/14/2022]
Abstract
A specific bone capillary subtype, namely type H vessels, with high expression of CD31 and endomucin, was shown to couple angiogenesis and osteogenesis recently. The number of type H vessels in bone tissue declines with age, and the underlying mechanism for this reduction is unclear. Here, we report that microRNA-188-3p (miR-188-3p) involves this process. miRNA-188-3p expression is upregulated in skeletal endothelium and negatively regulates the formation of type H vessels during ageing. Mice with depletion of miR-188 showed an alleviated age-related decline in type H vessels. In contrast, endothelial-specific overexpression of miR-188-3p reduced the number of type H vessels, leading to decreased bone mass and delayed bone regeneration. Mechanistically, we found that miR-188 inhibits type H vessel formation by directly targeting integrin β3 in endothelial cells. Our findings indicate that miR-188-3p is a key regulator of type H vessel formation and may be a potential therapeutic target for preventing bone loss and accelerating bone regeneration.
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Affiliation(s)
- Wen-Zhen He
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Mi Yang
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Yangzi Jiang
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Chen He
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Yu-Chen Sun
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Ling Liu
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Mei Huang
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Yu-Rui Jiao
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Kai-Xuan Chen
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Jing Hou
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Min Huang
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Yi-Li Xu
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Xu Feng
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Ya Liu
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Qi Guo
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Hui Peng
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Yan Huang
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Tian Su
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Ye Xiao
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
| | - Yusheng Li
- Department of Orthopaedics, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Joint Degeneration and Injury, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Chao Zeng
- Department of Orthopaedics, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Joint Degeneration and Injury, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Guanghua Lei
- Department of Orthopaedics, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
- Hunan Key Laboratory of Joint Degeneration and Injury, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Xiang-Hang Luo
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, 410008, Hunan, China
| | - Chang-Jun Li
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, 410008, Hunan, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
- Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, 410008, Hunan, China.
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6
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Rios De La Rosa JM, Spadea A, Donno R, Lallana E, Lu Y, Puri S, Caswell P, Lawrence MJ, Ashford M, Tirelli N. Microfluidic-assisted preparation of RGD-decorated nanoparticles: exploring integrin-facilitated uptake in cancer cell lines. Sci Rep 2020; 10:14505. [PMID: 32879363 PMCID: PMC7468293 DOI: 10.1038/s41598-020-71396-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 08/06/2020] [Indexed: 12/21/2022] Open
Abstract
This study is about fine tuning the targeting capacity of peptide-decorated nanoparticles to discriminate between cells that express different integrin make-ups. Using microfluidic-assisted nanoprecipitation, we have prepared poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles with a PEGylated surface decorated with two different arginine-glycine-aspartic acid (RGD) peptides: one is cyclic (RGDFC) and has specific affinity towards αvβ3 integrin heterodimers; the other is linear (RGDSP) and is reported to bind equally αvβ3 and α5β1. We have then evaluated the nanoparticle internalization in two cell lines with a markedly different integrin fingerprint: ovarian carcinoma A2780 (almost no αvβ3, moderate in α5β1) and glioma U87MG (very high in αvβ3, moderate/high in α5β1). As expected, particles with cyclic RGD were heavily internalized by U87MG (proportional to the peptide content and abrogated by anti-αvβ3) but not by A2780 (same as PEGylated particles). The linear peptide, on the other hand, did not differentiate between the cell lines, and the uptake increase vs. control particles was never higher than 50%, indicating a possible low and unselective affinity for various integrins. The strong preference of U87MG for cyclic (vs. linear) peptide-decorated nanoparticles was shown in 2D culture and further demonstrated in spheroids. Our results demonstrate that targeting specific integrin make-ups is possible and may open the way to more precise treatment, but more efforts need to be devoted to a better understanding of the relation between RGD structure and their integrin-binding capacity.
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Affiliation(s)
- Julio M Rios De La Rosa
- North West Centre for Advanced Drug Delivery (NoWCADD), School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
- Cambridge Enterprise Limited, University of Cambridge, The Hauser Forum, 3 Charles Babbage Road, Cambridge, CB3 0GT, UK.
| | - Alice Spadea
- North West Centre for Advanced Drug Delivery (NoWCADD), School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Roberto Donno
- North West Centre for Advanced Drug Delivery (NoWCADD), School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
- Laboratory for Polymers and Biomaterials, Fondazione Istituto Italiano di Tecnologia, 16163, Genova, Italy
| | - Enrique Lallana
- North West Centre for Advanced Drug Delivery (NoWCADD), School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Yu Lu
- North West Centre for Advanced Drug Delivery (NoWCADD), School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Sanyogitta Puri
- Advanced Drug Delivery, Pharmaceutical Sciences, R & D, AstraZeneca, Cambridge, UK
| | - Patrick Caswell
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, UK
| | - M Jayne Lawrence
- North West Centre for Advanced Drug Delivery (NoWCADD), School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Marianne Ashford
- Advanced Drug Delivery, Pharmaceutical Sciences, R & D, AstraZeneca, Macclesfield, UK
| | - Nicola Tirelli
- North West Centre for Advanced Drug Delivery (NoWCADD), School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
- Laboratory for Polymers and Biomaterials, Fondazione Istituto Italiano di Tecnologia, 16163, Genova, Italy.
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7
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Huang R, Rofstad EK. Integrins as therapeutic targets in the organ-specific metastasis of human malignant melanoma. J Exp Clin Cancer Res 2018; 37:92. [PMID: 29703238 PMCID: PMC5924434 DOI: 10.1186/s13046-018-0763-x] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 04/16/2018] [Indexed: 02/07/2023] Open
Abstract
Integrins are a large family of adhesion molecules that mediate cell-cell and cell-extracellular matrix interactions. Among the 24 integrin isoforms, many have been found to be associated with tumor angiogenesis, tumor cell migration and proliferation, and metastasis. Integrins, especially αvβ3, αvβ5 and α5β1, participate in mediating tumor angiogenesis by interacting with the vascular endothelial growth factor and angiopoietin-Tie signaling pathways. Melanoma patients have a poor prognosis when the primary tumor has generated distant metastases, and the melanoma metastatic site is an independent predictor of the survival of these patients. Different integrins on the melanoma cell surface preferentially direct circulating melanoma cells to different organs and promote the development of metastases at specific organ sites. For instance, melanoma cells expressing integrin β3 tend to metastasize to the lungs, whereas those expressing integrin β1 preferentially generate lymph node metastases. Moreover, tumor cell-derived exosomes which contain different integrins may prepare a pre-metastatic niche in specific organs and promote organ-specific metastases. Because of the important role that integrins play in tumor angiogenesis and metastasis, they have become promising targets for the treatment of advanced cancer. In this paper, we review the integrin isoforms responsible for angiogenesis and organ-specific metastasis in malignant melanoma and the inhibitors that have been considered for the future treatment of metastatic disease.
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Affiliation(s)
- Ruixia Huang
- Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Ullernchausseen 70, 0379, Oslo, Norway.
| | - Einar K Rofstad
- Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Ullernchausseen 70, 0379, Oslo, Norway
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8
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Yue J, Zhang K, Chen J. Role of integrins in regulating proteases to mediate extracellular matrix remodeling. CANCER MICROENVIRONMENT 2012; 5:275-83. [PMID: 22437309 DOI: 10.1007/s12307-012-0101-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 03/01/2012] [Indexed: 01/09/2023]
Abstract
The extracellular matrix (ECM) is an extracellular scaffold composed of complex mixtures of proteins that plays a pivotal role in tumor progression. ECM remodeling is crucial for tumor migration and invasion during the process of metastasis. ECM can be remodeled by several processes including synthesis, contraction and proteolytic degradation. In order to cross through the ECM barriers, malignant cells produce a spectrum of extracellular proteinases including matrix metalloproteinases (MMPs), serine proteases (mainly the urokinase plasminogen activator (uPA) system) and cysteine proteases to degrade ECM components. As major adhesion molecules to support cell attachment to ECM, integrins play critical roles in tumor progression by enhancing tumor cell survival, migration and invasion. Previous studies have shown that integrins can regulate the expression and activity of these proteases through different pathways. This review summarizes the roles of MMPs and uPA system in ECM remodeling and discusses the regulatory functions of integrins on these proteases in invasive tumors.
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Affiliation(s)
- Jiao Yue
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 YueYang Road, Shanghai, 200031, China
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9
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Wu X, Reddy DS. Integrins as receptor targets for neurological disorders. Pharmacol Ther 2011; 134:68-81. [PMID: 22233753 DOI: 10.1016/j.pharmthera.2011.12.008] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 12/15/2011] [Indexed: 12/18/2022]
Abstract
This review focuses on the neurobiology of integrins, pathophysiological roles of integrins in neuroplasticity and nervous system disorders, and therapeutic implications of integrins as potential drug targets and possible delivery pathways. Neuroplasticity is a central phenomenon in many neurological conditions such as seizures, trauma, and traumatic brain injury. During the course of many brain diseases, in addition to intracellular compartment changes, alterations in non-cell compartments such as extracellular matrix (ECM) are recognized as an essential process in forming and reorganizing neural connections. Integrins are heterodimeric transmembrane receptors that mediate cell-ECM and cell-cell adhesion events. Although the mechanisms of neuroplasticity remain unclear, it has been suggested that integrins undergo plasticity including clustering through interactions with ECM proteins, modulating ion channels, intracellular Ca(2+) and protein kinase signaling, and reorganization of cytoskeletal filaments. As cell surface receptors, integrins are central to the pathophysiology of many brain diseases, such as epilepsy, and are potential targets for the development of new drugs for neurological disorders.
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Affiliation(s)
- Xin Wu
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center College of Medicine, Bryan, TX 77807, USA
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10
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Jannat RA, Dembo M, Hammer DA. Neutrophil adhesion and chemotaxis depend on substrate mechanics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:194117. [PMID: 20473350 PMCID: PMC2867619 DOI: 10.1088/0953-8984/22/19/194117] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Neutrophil adhesion to the vasculature and chemotaxis within tissues play critical roles in the inflammatory response to injury and pathogens. Unregulated neutrophil activity has been implicated in the progression of numerous chronic and acute diseases such as rheumatoid arthritis, asthma, and sepsis. Cell migration of anchorage-dependent cells is known to depend on both chemical and mechanical interactions. Although neutrophil responses to chemical cues have been well characterized, little is known about the effect of underlying tissue mechanics on neutrophil adhesion and migration. To address this question, we quantified neutrophil migration and traction stresses on compliant hydrogel substrates with varying elasticity in a micro-machined gradient chamber in which we could apply either a uniform concentration or a precise gradient of the bacterial chemoattractant fMLP. Neutrophils spread more extensively on substrates of greater stiffness. In addition, increasing the stiffness of the substrate leads to a significant increase in the chemotactic index for each fMLP gradient tested. As the substrate becomes stiffer, neutrophils generate higher traction forces without significant changes in cell speed. These forces are often displayed in pairs and focused in the uropod. Increases in the mean fMLP concentration beyond the K(D) of the receptor lead to a decrease in chemotactic index on all surfaces. Blocking with an antibody against beta(2)-integrins leads to a significant reduction but not an elimination of directed motility on stiff materials, but no change in motility on soft materials, suggesting neutrophils can display both integrin-dependent and integrin-independent motility. These findings are critical for understanding how neutrophil migration may change in different mechanical environments in vivo and can be used to guide the design of migration inhibitors that more efficiently target inflammation.
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Affiliation(s)
- Risat A. Jannat
- Department of Bioengineering University of Pennsylvania 240 Skirkanich Hall 210 S. 33 Street Philadelphia, PA 19104
| | - Micah Dembo
- Department of Biomedical Engineering Boston University 44 Cummington St. Boston, MA 02215
| | - Daniel A. Hammer
- Department of Bioengineering University of Pennsylvania 240 Skirkanich Hall 210 S. 33 Street Philadelphia, PA 19104
- Department of Chemical and Biomolecular Engineering University of Pennsylvania 311A Towne Building 220 South 33 Street Philadelphia, PA 19104
- To whom correspondence should be addressed at: Department of Bioengineering University of Pennsylvania 240 Skirkanich Hall 210 S. 33 Street Philadelphia, PA 19104 Office: 215-573-6761 Fax: 215-573-2071
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11
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Complement disorders and hereditary angioedema. J Allergy Clin Immunol 2010; 125:S262-71. [DOI: 10.1016/j.jaci.2009.10.063] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 10/01/2009] [Accepted: 10/07/2009] [Indexed: 01/28/2023]
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12
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Hu X, Wohler JE, Dugger KJ, Barnum SR. beta2-integrins in demyelinating disease: not adhering to the paradigm. J Leukoc Biol 2009; 87:397-403. [PMID: 20007244 DOI: 10.1189/jlb.1009654] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The beta(2)-integrins are a subfamily of integrins expressed on leukocytes that play an essential role in leukocyte trafficking, activation, and many other functions. Studies in EAE, the animal model for multiple sclerosis, show differential requirements for beta(2)-integrins in this disease model, ranging from critical in the case of LFA-1 (CD11a/CD18) to unimportant in the case of CD11d/CD18. Importantly, expression of beta(2)-integrins on T cell subsets provides some clues as to the function(s) these adhesion molecules play in disease development. For example, transferred EAE studies have shown that Mac-1 (CD11b/CD18) expression on alphabeta T cells is critical for disease development, and the absence of LFA-1 on Tregs in recipient mice results in exacerbated disease. In this review, we summarize recent findings regarding the role of beta(2)-integrins in demyelinating disease and new information about the role of beta(2)-integrins with respect to alterations in Treg numbers and function. In addition, we discuss the potential for targeting beta(2)-integrins in human demyelinating disease in light of the recent animal model studies.
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Affiliation(s)
- Xianzhen Hu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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13
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Lin EYS, Guckian KM, Silvian L, Chin D, Ann Boriack-Sjodin P, van Vlijmen H, Friedman JE, Scott DM. Structure–activity relationship of ortho- and meta-phenol based LFA-1 ICAM inhibitors. Bioorg Med Chem Lett 2008; 18:5245-8. [DOI: 10.1016/j.bmcl.2008.08.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 08/14/2008] [Accepted: 08/18/2008] [Indexed: 11/28/2022]
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14
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Design and synthesis of a series of meta aniline-based LFA-1 ICAM inhibitors. Bioorg Med Chem Lett 2008; 18:5249-51. [DOI: 10.1016/j.bmcl.2008.08.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 08/14/2008] [Accepted: 08/18/2008] [Indexed: 11/20/2022]
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15
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Woodside DG, Vanderslice P. Cell adhesion antagonists: therapeutic potential in asthma and chronic obstructive pulmonary disease. BioDrugs 2008; 22:85-100. [PMID: 18345706 DOI: 10.2165/00063030-200822020-00002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) and asthma are inflammatory diseases of the lung where a hallmark feature is excessive leukocyte infiltration that leads to tissue injury. Cell adhesion molecules (e.g. selectins and integrins) play a key role in cell trafficking, and in the lung they regulate leukocyte extravasation, migration within the interstitium, cellular activation, and tissue retention. All selectin family members (including L-selectin, P-selectin, and E-selectin) and many of the beta1 and beta2 integrins appear to be important therapeutic targets, as numerous animal studies have demonstrated essential roles for these cell adhesion molecules in lung inflammation. Not surprisingly, these families of adhesion molecules have been under intense investigation by the pharmaceutical industry for the development of novel therapeutics. Integrins are validated drug targets, as drugs that antagonize integrin alphaIIbbeta3 (e.g. abciximab), integrin alphaLbeta2 (efalizumab), and integrin alpha4beta1 (natalizumab) are currently US FDA-approved for acute coronary syndromes, psoriasis, and multiple sclerosis, respectively. However, none has been approved for indications related to asthma or COPD. Here, we provide an overview of roles played by selectins and integrins in lung inflammation. We also describe recent clinical results (both failures and successes) in developing adhesion molecule antagonists, with specific emphasis on those targets that may have potential benefit in asthma and COPD. Early clinical trials using selectin and integrin antagonists have met with limited success. However, recent positive phase II clinical trials with a small-molecule selectin antagonist (bimosiamose) and a small-molecule integrin alpha4beta1 antagonist (valategrast [R411]), have generated enthusiastic anticipation that novel strategies to treat asthma and COPD may be forthcoming.
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Affiliation(s)
- Darren G Woodside
- Department of Drug Discovery, Biological Sciences, Encysive Pharmaceuticals Inc., Houston, Texas, USA.
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16
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Waldeck-Weiermair M, Zoratti C, Osibow K, Balenga N, Goessnitzer E, Waldhoer M, Malli R, Graier WF. Integrin clustering enables anandamide-induced Ca2+ signaling in endothelial cells via GPR55 by protection against CB1-receptor-triggered repression. J Cell Sci 2008; 121:1704-1717. [PMID: 18445684 PMCID: PMC4067516 DOI: 10.1242/jcs.020958] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Although the endocannabinoid anandamide is frequently described to act predominantly in the cardiovascular system, the molecular mechanisms of its signaling remained unclear. In human endothelial cells, two receptors for anandamide were found, which were characterized as cannabinoid 1 receptor (CB1R; CNR1) and G-protein-coupled receptor 55 (GPR55). Both receptors trigger distinct signaling pathways. It crucially depends on the activation status of integrins which signaling cascade becomes promoted upon anandamide stimulation. Under conditions of inactive integrins, anandamide initiates CB1R-derived signaling, including Gi-protein-mediated activation of spleen tyrosine kinase (Syk), resulting in NFkappaB translocation. Furthermore, Syk inhibits phosphoinositide 3-kinase (PI3K) that represents a key protein in the transduction of GPR55-originated signaling. However, once integrins are clustered, CB1R splits from integrins and, thus, Syk cannot further inhibit GPR55-triggered signaling resulting in intracellular Ca2+ mobilization from the endoplasmic reticulum (ER) via a PI3K-Bmx-phospholipase C (PLC) pathway and activation of nuclear factor of activated T-cells. Altogether, these data demonstrate that the physiological effects of anandamide on endothelial cells depend on the status of integrin clustering.
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Affiliation(s)
| | - Cristina Zoratti
- Institute of Molecular Biology and Biochemistry, Medical University Graz, Graz, A8010, Austria
| | - Karin Osibow
- Institute of Molecular Biology and Biochemistry, Medical University Graz, Graz, A8010, Austria
| | - Nariman Balenga
- Institute of Experimental and Clinical Pharmacology, Medical University Graz, Graz, A8010, Austria
| | - Edith Goessnitzer
- Institute of Pharmaceutical Chemistry, University Graz, Graz Austria
| | - Maria Waldhoer
- Institute of Experimental and Clinical Pharmacology, Medical University Graz, Graz, A8010, Austria
| | - Roland Malli
- Institute of Molecular Biology and Biochemistry, Medical University Graz, Graz, A8010, Austria
| | - Wolfgang F. Graier
- Institute of Molecular Biology and Biochemistry, Medical University Graz, Graz, A8010, Austria
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17
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Sadhu C, Hendrickson L, Dick KO, Potter TG, Staunton DE. Novel tools for functional analysis of CD11c: activation-specific, activation-independent, and activating antibodies. J Immunoassay Immunochem 2008; 29:42-57. [PMID: 18080879 DOI: 10.1080/15321810701735062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Functions and binding properties of four CD11c-specific mAbs are described here. The mAb 496B stimulated, while 496K inhibited ligand binding of CD11c. The stimulatory mAb, 496B, as well as the inhibitory mAbs BU15 and 496 K appear to act allosterically, as they do not bind the CD11c I domain. The mAb 3.9 bound preferentially to activated forms of CD11c and the binding was divalent cation dependent. CD11c binding to 3.9 recapitulates many of the integrin-ligand interactions. Our data suggest that 3.9 is a competitive antagonist, BU15 and 496K are allosteric antagonists, and 496B is an allosteric agonist of CD11c. These mAbs provide a set of tools to study the functions of the dendritic cell marker, CD11c.
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18
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FARJO RAFAL, FLIESLER STEVENJ, NAASH MUNAI. Effect of Rds abundance on cone outer segment morphogenesis, photoreceptor gene expression, and outer limiting membrane integrity. J Comp Neurol 2008; 504:619-30. [PMID: 17722028 PMCID: PMC2072815 DOI: 10.1002/cne.21476] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We examined the molecular, structural, and functional consequences on cone photoreceptors of the neural retinal leucine zipper knockout (Nrl(-/-)) mice when only one allele of retinal degeneration slow (Rds) is present (Rds(+/-)/Nrl(-/-)). Quantitative RT-PCR and immunoblot analysis were used to assess the expression levels of several phototransduction genes; electroretinography was used to assess quantitatively the retinal responsiveness to light; and immunohistochemistry and ultrastructural analysis were used to examine retinal protein distribution and morphology, respectively. In Rds/Nrl double-null mice, S-cones form dysmorphic outer segments that lack lamellae and fail to associate properly with the cone matrix sheath and the outer limiting membrane. In Rds(+/-)/Nrl(-/-) mice, cones form oversized and disorganized outer segment lamellae; although outer limiting membrane associations are maintained, normal interactions with cone matrix sheaths are not, and photoreceptor rosette formation is observed. These retinas produce significantly higher photopic a-wave and b-wave amplitudes than do those of Rds(-/-)/Nrl(-/-) mice, and the levels of several cone phototransduction genes are significantly increased coincidently with the presence of Rds and partial lamellae formation. Thus, as in rod photoreceptors, expression of only one Rds allele is unable to support normal outer segment morphogenesis in cones. However, cone lamellae assembly, albeit disorganized, concomitantly permits outer limiting membrane association, and this appears to be linked to photoreceptor rosette formation in the rodless (cone-only) Nrl(-/-) retina. In addition, photoreceptor gene expression alterations occur in parallel with changes in Rds levels.
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Affiliation(s)
- RAFAL FARJO
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - STEVEN J. FLIESLER
- Departments of Ophthalmology and Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri 63104
| | - MUNA I. NAASH
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
- *Correspondence to: Muna I. Naash, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., BMSB 781, Oklahoma City, OK 73104. E-mail:
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19
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Cell integrins: commonly used receptors for diverse viral pathogens. Trends Microbiol 2007; 15:500-7. [DOI: 10.1016/j.tim.2007.10.001] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Revised: 08/13/2007] [Accepted: 10/19/2007] [Indexed: 01/23/2023]
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20
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Smith SS, Barnum SR. Differential expression of beta 2-integrins and cytokine production between gammadelta and alphabeta T cells in experimental autoimmune encephalomyelitis. J Leukoc Biol 2007; 83:71-9. [PMID: 17928460 DOI: 10.1189/jlb.0407263] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The expression of beta 2-integrins on gammadelta T cells in naïve mice or those with experimental autoimmune encephalomyelitis (EAE) remains poorly characterized. We compared beta 2-integrin expression and cytokine production between gammadelta and alphabeta T cells over the acute course of EAE. We observed that unlike in alphabeta T cells, beta 2-integrin expression on gammadelta T cells increased significantly from baseline, peaked at Day 10, and remained unchanged in the draining lymph nodes or declined in the spleen and CNS by Day 15. In addition, IFN-gamma- and TNF-alpha-producing gammadelta T cells infiltrated the CNS rapidly and produced significantly more of these cytokines than alphabeta T cells throughout the course of EAE. These results suggest unique roles for beta 2-integrins in the trafficking of gammadelta versus alphabeta T cells during EAE and that gammadelta T cells infiltrate the CNS rapidly, producing cytokines, which modulate acute disease.
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Affiliation(s)
- Sherry S Smith
- Department of Microbiology, University of Alabama at Birmingham, 845 19th St. S., BBRB/842, Birmingham, AL 35294, USA
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21
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Shi M, Foo SY, Tan SM, Mitchell EP, Law SKA, Lescar J. A structural hypothesis for the transition between bent and extended conformations of the leukocyte beta2 integrins. J Biol Chem 2007; 282:30198-206. [PMID: 17673459 DOI: 10.1074/jbc.m701670200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Integrins mediate cell adhesion in response to activation signals that trigger conformational changes within their ectodomain. It is thought that a compact bent conformation of the molecule represents its physiological low affinity state and extended conformations its active state. We have determined the structure of two integrin fragments of the beta2 subunit. The first structure, consisting of the plexin-semaphorin-integrin domain, hybrid, integrin-epidermal growth factor 1 (I-EGF1), and I-EGF2 domains (PHE2), showed an L-shaped conformation with the bend located between the I-EGF1 and I-EGF2 domains. The second structure, which includes, in addition, the I-EGF3 domain, showed an extended conformation. The major reorientation of I-EGF2 with respect to the other domains in the two structures is accompanied by a change of torsion angle of the disulfide bond between Cys(461)-Cys(492) by 180 degrees and the conversion of a short alpha-helix (residues Ser(468)-Cys(475)) into a flexible coil. Based on the PHE2 structure, we introduced a disulfide bond between the plexin-semaphorin-integrin domain and I-EGF2 domains in the beta2 subunit. The resultant alphaLbeta2 integrin (leukocyte function-associated antigen-1) variant was locked in a bent state and could not be detected with the monoclonal antibody KIM127 in Mg(2+)/EGTA. However, it retained the binding activity to ICAM-1. These results provide a structural hypothesis for our understanding of the transition between the resting and active states of leukocyte function-associated antigen-1.
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Affiliation(s)
- Minlong Shi
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, Singapore 637551
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22
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Qiu P, Kurpakus-Wheater M, Sosne G. Matrix metalloproteinase activity is necessary for thymosin beta 4 promotion of epithelial cell migration. J Cell Physiol 2007; 212:165-73. [PMID: 17348036 DOI: 10.1002/jcp.21012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Studies from our laboratory provide substantial evidence that thymosin beta 4, (Tbeta(4)), an actin-sequestering protein, promotes corneal wound healing through its ability to stimulate epithelial cell migration. Matrix metalloproteinases (MMPs), which are expressed in a wide variety of tissues including the cornea, also play a key role in epithelial cell migration and wound healing. In this study we investigated the role of MMPs in Tbeta(4)-stimulated corneal epithelial cell migration. In Boyden chamber assays, XG076, an inhibitor of the conversion of pro- to active MMPs, had no effect on epithelial cell migration stimulated by exogenous activated MMP-1. However, in in vitro migration assays where the activation of pro-MMPs was blocked, XG076 significantly inhibited cell migration and wound healing in the presence or absence of Tbeta(4). GM6001, a broad-spectrum inhibitor of active MMPs and selective MMP inhibitors, also suppressed Tbeta(4)-stimulated cell migration. Tbeta(4) upregulated MMP-1 gene and protein expression in primary human corneal epithelial cells and in transformed human corneal epithelial cells following scrape wounding. From these results we conclude that MMP catalytic activity is necessary for Tbeta(4) promotion of epithelial cell migration. These novel findings are the first to demonstrate a functional link between the two.
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Affiliation(s)
- Ping Qiu
- Department of Ophthalmology, Kresge Eye Institute, Detroit, Michigan 48201, USA
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23
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Sadhu C, Ting HJ, Lipsky B, Hensley K, Garcia-Martinez LF, Simon SI, Staunton DE. CD11c/CD18: novel ligands and a role in delayed-type hypersensitivity. J Leukoc Biol 2007; 81:1395-403. [PMID: 17389580 DOI: 10.1189/jlb.1106680] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
CD11c, a member of the leukointegrin family, is expressed prominently on tissue macrophages and dendritic cells and binds to complement fragment (iC3b), provisional matrix molecules (fibrinogen), and the Ig superfamily cell adhesion molecule, ICAM-1. CD11c has been proposed to function in phagocytosis, cell migration, and cytokine production by monocytes/macrophages as well as induction of T cell proliferation by Langerhans cells. Using assays to quantify CD11c-mediated cell adhesion, we demonstrate that CD11c recognizes ICAM-2 and VCAM-1. The CD11c-binding site on VCAM-1 appears to be different from that used by the integrin alpha4. CD11c and alpha4beta1 contributed to monocyte capture and transmigration on inflamed human aortic endothelial cells. We discovered that the anti-mouse CD11c mAb N418 blocks CD11c binding to iC3b, ICAM-1, and VCAM-1. Treatment of mice with N418 reduced SRBC-induced delayed-type hypersensitivity significantly. CD11c appeared to contribute predominantly to the sensitization phase and somewhat less to the response to SRBC challenge. This suggests a novel role for CD11c during leukocyte recruitment, antigen uptake, and the survival of APC.
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Affiliation(s)
- Chanchal Sadhu
- ICOS Corporation, 22021 20th Ave., S.E., Bothell, WA 98021, USA.
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24
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Kinashi T. Integrin Regulation of Lymphocyte Trafficking: Lessons from Structural and Signaling Studies. Adv Immunol 2007; 93:185-227. [PMID: 17383542 DOI: 10.1016/s0065-2776(06)93005-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
High trafficking capability of lymphocytes is crucial in immune surveillance and antigen responses. Central to this regulatory process is a dynamic control of lymphocyte adhesion behavior regulated by chemokines and adhesion receptors such as integrins. Modulation of lymphocyte adhesive responses occurs in a wide range of time window from less than a second to hours, enabling rolling lymphocyte to attach to and migrate through endothelium and interact with antigen-presenting cells. While there has been a rapid progress in the understanding of integrin structure, elucidation of signaling events to relay extracellular signaling to integrins in physiological contexts has recently emerged from studies using gene-targeting and gene-silencing technique. Regulatory molecules critical for integrin activity control distribution of integrins, polarized cell morphology and motility, suggesting a signaling network that coordinates integrin function with lymphocyte migration. Here, I review recent studies of integrin structural changes and intracellular signal molecules that trigger integrin activation (inside-out signals), and discuss molecular mechanisms that control lymphocyte integrins and how inside-out signals coordinately modulate adhesive reactions and cell shape and migration.
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Affiliation(s)
- Tatsuo Kinashi
- Department of Molecular Genetics, Institute of Biomedical Science, Kansai Medical University, Kyoto 606, Japan
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25
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Abstract
Integrins are large modular cell-surface receptors that regulate almost every aspect of cellular function through bidirectional signals transmitted across the lipid bilayer. Regulation of integrin activity is accomplished by complex and still incompletely understood biochemical pathways that modify integrin ligand binding, clustering, trafficking, and signaling functions. The dynamic tertiary and quaternary changes required to channel some of these activities have hampered, until recently, the crystal structure determination of these heterodimeric receptors. In this chapter, we review the methods used to purify and characterize these proteins biophysically and functionally, and to derive their three-dimensional structures.
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Affiliation(s)
- Jian-Ping Xiong
- Structural Biology Program, Leukocyte Biology and Inflammation Program, Nephrology Division, Massachusetts General Hospital and Harvard Medical School, Charlestown, USA
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