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Cai C, Sun H, Hu L, Fan Z. Visualization of integrin molecules by fluorescence imaging and techniques. ACTA ACUST UNITED AC 2021; 45:229-257. [PMID: 34219865 PMCID: PMC8249084 DOI: 10.32604/biocell.2021.014338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Integrin molecules are transmembrane αβ heterodimers involved in cell adhesion, trafficking, and signaling. Upon activation, integrins undergo dynamic conformational changes that regulate their affinity to ligands. The physiological functions and activation mechanisms of integrins have been heavily discussed in previous studies and reviews, but the fluorescence imaging techniques -which are powerful tools for biological studies- have not. Here we review the fluorescence labeling methods, imaging techniques, as well as Förster resonance energy transfer assays used to study integrin expression, localization, activation, and functions.
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Affiliation(s)
- Chen Cai
- Department of Immunology, School of Medicine, UConn Health, Farmington, 06030, USA
| | - Hao Sun
- Department of Medicine, University of California, San Diego, La Jolla, 92093, USA
| | - Liang Hu
- Cardiovascular Institute of Zhengzhou University, Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450051, China
| | - Zhichao Fan
- Department of Immunology, School of Medicine, UConn Health, Farmington, 06030, USA
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2
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Perez DR, Sklar LA, Chigaev A, Matlawska-Wasowska K. Drug repurposing for targeting cyclic nucleotide transporters in acute leukemias - A missed opportunity. Semin Cancer Biol 2020; 68:199-208. [PMID: 32044470 DOI: 10.1016/j.semcancer.2020.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/01/2019] [Accepted: 02/03/2020] [Indexed: 02/08/2023]
Abstract
While current treatment regimens for acute leukemia can dramatically improve patient survival, there remains room for improvement. Due to its roles in cell differentiation, cell survival, and apoptotic signaling, modulation of the cyclic AMP (cAMP) pathway has provided a meaningful target in hematological malignancies. Several studies have demonstrated that gene expression profiles associated with increased pro-survival cAMP activity or downregulation of various pro-apoptotic factors associated with the cAMP pathway are apparent in acute leukemia patients. Previous work to increase leukemia cell intracellular cAMP focused on the use of cAMP analogs, stimulating cAMP production via transmembrane-associated adenylyl cyclases, or decreasing cAMP degradation by inhibiting phosphodiesterase activity. However, targeting cyclic nucleotide efflux by ATP-binding cassette (ABC) transporters represents an unexplored approach for modulation of intracellular cyclic nucleotide levels. Preliminary studies have shown that inhibition of cAMP efflux can stimulate leukemia cell differentiation, cell growth arrest, and apoptosis, indicating that targeting cAMP efflux may show promise for future therapeutic development. Furthermore, inhibition of cyclic nucleotide transporter activity may also contribute multiple anticancer benefits by reducing extracellular pro-survival signaling in malignant cells. Hence, several opportunities for drug repurposing may exist for targeting cyclic nucleotide transporters.
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Affiliation(s)
- Dominique R Perez
- Department of Pathology, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA; Center for Molecular Discovery, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA
| | - Larry A Sklar
- Department of Pathology, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA; Center for Molecular Discovery, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA; University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
| | - Alexandre Chigaev
- Department of Pathology, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA; Center for Molecular Discovery, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA; University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA.
| | - Ksenia Matlawska-Wasowska
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA; Department of Pediatrics, Division of Hematology-Oncology, Health Sciences Center, University of New Mexico, Albuquerque, NM, USA.
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3
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Xie J, Wang X, Ge H, Peng F, Zheng N, Wang Q, Tao L. Cx32 mediates norepinephrine-promoted EGFR-TKI resistance in a gap junction-independent manner in non-small-cell lung cancer. J Cell Physiol 2019; 234:23146-23159. [PMID: 31152452 DOI: 10.1002/jcp.28881] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 05/07/2019] [Accepted: 05/09/2019] [Indexed: 01/10/2023]
Abstract
The second-generation EGFR-TKI Afatinib is an irreversible ErbB family blocker used to treat patients with non-small-cell lung cancer (NSCLC). Unfortunately, resistance to this drug develops over time, and patients are always under great psychological pressure. A previous study showed that chronic stress hormones participate in EGFR-TKI resistance via β2 -AR signaling via an IL-6 dependent mechanism. Our study further explores a novel potential underlying mechanism. In the present study, we show that the stress hormone norepinephrine (NE) promotes Afatinib resistance by upregulating Cx32 expression. Furthermore, we, for the first time, find that Cx32 is a target gene for transcription factor CREB and NE enhances Cx32 mRNA expression by activation of CREB. We also demonstrate that Cx32 promotes Afatinib resistance by decreasing the degradation of EGFR-TKI resistance-associated proteins (MET, IGF-1R) and by increasing their transcription levels. Together, these results reveal that the stress hormone NE accelerates Afatinib resistance by increasing the expression of Cx32, which augments MET and IGF-1R levels in cancer cells and provides a promising therapeutic strategy against EGFR-TKI Afatinib resistance in NSCLC.
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Affiliation(s)
- Jie Xie
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Xiyan Wang
- Tumor Research Institute, Xinjiang Medical University Affiliated Tumor Hospital, Urumqi, Xinjiang, China
| | - Hui Ge
- Tumor Research Institute, Xinjiang Medical University Affiliated Tumor Hospital, Urumqi, Xinjiang, China
| | - Fuhua Peng
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Ningze Zheng
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Qin Wang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Liang Tao
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
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4
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Regulation of cell adhesion: a collaborative effort of integrins, their ligands, cytoplasmic actors, and phosphorylation. Q Rev Biophys 2019; 52:e10. [PMID: 31709962 DOI: 10.1017/s0033583519000088] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Integrins are large heterodimeric type 1 membrane proteins expressed in all nucleated mammalian cells. Eighteen α-chains and eight β-chains can combine to form 24 different integrins. They are cell adhesion proteins, which bind to a large variety of cellular and extracellular ligands. Integrins are required for cell migration, hemostasis, translocation of cells out from the blood stream and further movement into tissues, but also for the immune response and tissue morphogenesis. Importantly, integrins are not usually active as such, but need activation to become adhesive. Integrins are activated by outside-in activation through integrin ligand binding, or by inside-out activation through intracellular signaling. An important question is how integrin activity is regulated, and this topic has recently drawn much attention. Changes in integrin affinity for ligand binding are due to allosteric structural alterations, but equally important are avidity changes due to integrin clustering in the plane of the plasma membrane. Recent studies have partially solved how integrin cell surface structures change during activation. The integrin cytoplasmic domains are relatively short, but by interacting with a variety of cytoplasmic proteins in a regulated manner, the integrins acquire a number of properties important not only for cell adhesion and movement, but also for cellular signaling. Recent work has shown that specific integrin phosphorylations play pivotal roles in the regulation of integrin activity. Our purpose in this review is to integrate the present knowledge to enable an understanding of how cell adhesion is dynamically regulated.
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5
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Perez DR, Sklar LA, Chigaev A. Clioquinol: To harm or heal. Pharmacol Ther 2019; 199:155-163. [PMID: 30898518 DOI: 10.1016/j.pharmthera.2019.03.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/14/2019] [Indexed: 12/13/2022]
Abstract
Clioquinol, one of the first mass-produced drugs, was considered safe and efficacious for many years. It was used as an antifungal and an antiprotozoal drug until it was linked to an outbreak of subacute myelo-optic neuropathy (SMON), a debilitating disease almost exclusively confined to Japan. Today, new information regarding clioquinol targets and its mechanism of action, as well as genetic variation (SNPs) in efflux transporters in the Japanese population, provide a unique interpretation of the existing phenomena. Further understanding of clioquinol's role in the inhibition of cAMP efflux and promoting apoptosis might offer promise for the treatment of cancer and/or neurodegenerative diseases. Here, we highlight recent developments in the field and discuss possible connections, hypotheses and perspectives in clioquinol-related research.
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Affiliation(s)
- Dominique R Perez
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM 87131, USA; Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Larry A Sklar
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM 87131, USA; University of New Mexico Comprehensive Cancer Center, Albuquerque, NM 87131, USA; Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Alexandre Chigaev
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM 87131, USA; University of New Mexico Comprehensive Cancer Center, Albuquerque, NM 87131, USA; Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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6
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Dimitrov S, Lange T, Gouttefangeas C, Jensen ATR, Szczepanski M, Lehnnolz J, Soekadar S, Rammensee HG, Born J, Besedovsky L. Gα s-coupled receptor signaling and sleep regulate integrin activation of human antigen-specific T cells. J Exp Med 2019; 216:517-526. [PMID: 30755455 PMCID: PMC6400544 DOI: 10.1084/jem.20181169] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 12/03/2018] [Accepted: 01/11/2019] [Indexed: 12/26/2022] Open
Abstract
This study demonstrates a regulatory role of Gαs-coupled receptor agonists (catecholamines, prostaglandins, and adenosine) and sleep on integrin activation on T cells in humans. The findings point to a mechanism by which T cell responses are altered in several conditions characterized by aberrant levels of these substances. Efficient T cell responses require the firm adhesion of T cells to their targets, e.g., virus-infected cells, which depends on T cell receptor (TCR)–mediated activation of β2-integrins. Gαs-coupled receptor agonists are known to have immunosuppressive effects, but their impact on TCR-mediated integrin activation is unknown. Using multimers of peptide major histocompatibility complex molecules (pMHC) and of ICAM-1—the ligand of β2-integrins—we show that the Gαs-coupled receptor agonists isoproterenol, epinephrine, norepinephrine, prostaglandin (PG) E2, PGD2, and adenosine strongly inhibit integrin activation on human CMV- and EBV-specific CD8+ T cells in a dose-dependent manner. In contrast, sleep, a natural condition of low levels of Gαs-coupled receptor agonists, up-regulates integrin activation compared with nocturnal wakefulness, a mechanism possibly underlying some of the immune-supportive effects of sleep. The findings are also relevant for several pathologies associated with increased levels of Gαs-coupled receptor agonists (e.g., tumor growth, malaria, hypoxia, stress, and sleep disturbances).
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Affiliation(s)
- Stoyan Dimitrov
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany .,German Center for Diabetes Research (DZD), Tübingen, Germany.,Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich, University of Tübingen, Tübingen, Germany
| | - Tanja Lange
- Clinic for Rheumatology and Clinical Immunology, University of Lübeck, Lübeck, Germany
| | - Cécile Gouttefangeas
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Anja T R Jensen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Szczepanski
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jannik Lehnnolz
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Surjo Soekadar
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Clinical Neurotechnology Laboratory, Department of Psychiatry and Psychotherapy, Neuroscience Research Center, Charité - University Medicine Berlin, Berlin, Germany
| | - Hans-Georg Rammensee
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Tübingen, Germany.,Partner Site Tübingen, German Cancer Consortium, Tübingen, Germany
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD), Tübingen, Germany.,Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich, University of Tübingen, Tübingen, Germany
| | - Luciana Besedovsky
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
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7
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Avci S, Gur-Cohen S, Avemaria F, Lapidot T. Adhesion Assay for Murine Bone Marrow Hematopoietic Stem Cells. Bio Protoc 2017; 7:e2135. [PMID: 34458456 DOI: 10.21769/bioprotoc.2135] [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: 08/24/2016] [Revised: 11/22/2016] [Accepted: 01/21/2017] [Indexed: 11/02/2022] Open
Abstract
Hematopoietic stem cells (HSCs) are defined by their functional abilities to self-renew and to give rise to all mature blood and immune cell types throughout life. Most HSCs are retained in a non-motile quiescent state within a specialized protective microenvironment in the bone marrow (BM) termed the niche. HSCs are typically distinguished from other adult stem cells by their motility capacity. Movement of HSCs across the physical barrier of the marrow extracellular matrix and blood vessel endothelial cells is facilitated by suppression of adhesion interactions, which are essential to preserve the stem cells retained within their BM niches. Importantly, homing of HSCs to the BM following clinical transplantation is a crucial first step for the repopulation of ablated BM as in the case of curative treatment strategies for hematologic malignancies. The homing process ends with selective access and anchorage of HSCs to their specialized niches within the BM. Adhesion molecules are targets to either enhance homing in cases of stem cell transplantation or reduce BM retention to harvest mobilized HSCs from the blood of matched donors. A major adhesion protein which is functionally expressed on HSCs and is involved in their homing and retention is the integrin alpha4beta1 (Very late antigen-4; VLA4). In this protocol we introduce an adhesion assay optimized for VLA4 expressing murine bone marrow stem cells. This assay quantifies adherent HSCs by flow cytometry with HSC enriching cell surface markers subsequent to the isolation of VLA4 expressing adherent cells.
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Affiliation(s)
- Seymen Avci
- Weizmann Institute of Science, Immunology department, Rehovot, Israel
| | - Shiri Gur-Cohen
- Weizmann Institute of Science, Immunology department, Rehovot, Israel
| | | | - Tsvee Lapidot
- Weizmann Institute of Science, Immunology department, Rehovot, Israel
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8
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Weber MR, Zuka M, Lorger M, Tschan M, Torbett BE, Zijlstra A, Quigley JP, Staflin K, Eliceiri BP, Krueger JS, Marchese P, Ruggeri ZM, Felding BH. Activated tumor cell integrin αvβ3 cooperates with platelets to promote extravasation and metastasis from the blood stream. Thromb Res 2017; 140 Suppl 1:S27-36. [PMID: 27067975 DOI: 10.1016/s0049-3848(16)30095-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Metastasis is the main cause of death in cancer patients, and understanding mechanisms that control tumor cell dissemination may lead to improved therapy. Tumor cell adhesion receptors contribute to cancer spreading. We noted earlier that tumor cells can expressing the adhesion receptor integrin αvβ3 in distinct states of activation, and found that cells which metastasize from the blood stream express it in a constitutively high affinity form. Here, we analyzed steps of the metastatic cascade in vivo and asked, when and how the affinity state of integrin αvβ3 confers a critical advantage to cancer spreading. Following tumor cells by real time PCR, non-invasive bioluminescence imaging, intravital microscopy and histology allowed us to identify tumor cell extravasation from the blood stream as a rate-limiting step supported by high affinity αvβ3. Successful transendothelial migration depended on cooperation between tumor cells and platelets involving the high affinity tumor cell integrin and release of platelet granules. Thus, this study identifies the high affinity conformer of integrin αvβ3 and its interaction with platelets as critical for early steps during hematogenous metastasis and target for prevention of metastatic disease.
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Affiliation(s)
- Martin R Weber
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Masahiko Zuka
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Mihaela Lorger
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Mario Tschan
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Bruce E Torbett
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Andries Zijlstra
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, USA
| | - James P Quigley
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Karin Staflin
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Brian P Eliceiri
- Department of Surgery, University of California San Diego, San Diego, CA 92103, USA
| | - Joseph S Krueger
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Patrizia Marchese
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Zaverio M Ruggeri
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Brunhilde H Felding
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA; Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, USA.
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9
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Perez DR, Smagley Y, Garcia M, Carter MB, Evangelisti A, Matlawska-Wasowska K, Winter SS, Sklar LA, Chigaev A. Cyclic AMP efflux inhibitors as potential therapeutic agents for leukemia. Oncotarget 2016; 7:33960-82. [PMID: 27129155 PMCID: PMC5085131 DOI: 10.18632/oncotarget.8986] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 04/16/2016] [Indexed: 12/24/2022] Open
Abstract
Apoptotic evasion is a hallmark of cancer. We propose that some cancers may evade cell death by regulating 3'-5'-cyclic adenosine monophosphate (cAMP), which is associated with pro-apoptotic signaling. We hypothesize that leukemic cells possess mechanisms that efflux cAMP from the cytoplasm, thus protecting them from apoptosis. Accordingly, cAMP efflux inhibition should result in: cAMP accumulation, activation of cAMP-dependent downstream signaling, viability loss, and apoptosis. We developed a novel assay to assess cAMP efflux and performed screens to identify inhibitors. In an acute myeloid leukemia (AML) model, several identified compounds reduced cAMP efflux, appropriately modulated pathways that are responsive to cAMP elevation (cAMP-responsive element-binding protein phosphorylation, and deactivation of Very Late Antigen-4 integrin), and induced mitochondrial depolarization and caspase activation. Blocking adenylyl cyclase activity was sufficient to reduce effects of the most potent compounds. These compounds also decreased cAMP efflux and viability of B-lineage acute lymphoblastic leukemia (B-ALL) cell lines and primary patient samples, but not of normal primary peripheral blood mononuclear cells. Our data suggest that cAMP efflux is a functional feature that could be therapeutically targeted in leukemia. Furthermore, because some of the identified drugs are currently used for treating other illnesses, this work creates an opportunity for repurposing.
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Affiliation(s)
- Dominique R. Perez
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM, USA
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Yelena Smagley
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM, USA
| | - Matthew Garcia
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM, USA
| | - Mark B. Carter
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM, USA
| | - Annette Evangelisti
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM, USA
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Ksenia Matlawska-Wasowska
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- Department of Pediatrics, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Stuart S. Winter
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- Department of Pediatrics, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Larry A. Sklar
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM, USA
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Alexandre Chigaev
- University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, USA
- University of New Mexico Center for Molecular Discovery, Albuquerque, NM, USA
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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10
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Felouzis V, Hermand P, de Laissardière GT, Combadière C, Deterre P. Comprehensive analysis of chemokine-induced cAMP-inhibitory responses using a real-time luminescent biosensor. Cell Signal 2015; 28:120-9. [PMID: 26515128 DOI: 10.1016/j.cellsig.2015.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 10/23/2015] [Indexed: 01/29/2023]
Abstract
Chemokine receptors are members of the G-protein-coupled receptor (GPCR) family coupled to members of the Gi class, whose primary function is to inhibit the cellular adenylate cyclase. We used a cAMP-related and PKA-based luminescent biosensor (GloSensor™ F-22) to monitor the real-time downstream response of chemokine receptors, especially CX3CR1 and CXCR4, after activation with their cognate ligands CX3CL1 and CXCL12. We found that the amplitudes and kinetic profiles of the chemokine responses were conserved in various cell types and were independent of the nature and concentration of the molecules used for cAMP prestimulation, including either the adenylate cyclase activator forskolin or ligands mediating Gs-mediated responses like prostaglandin E2 or beta-adrenergic agonist. We conclude that the cAMP chemokine response is robustly conserved in various inflammatory conditions. Moreover, the cAMP-related luminescent biosensor appears as a valuable tool to analyze the details of Gi-mediated cAMP-inhibitory cellular responses, even in native conditions and could help to decipher their precise role in cell function.
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Affiliation(s)
- Virginia Felouzis
- Sorbonne Universités, UPMC Université Paris 06, Inserm U 1135, CNRS ERL 8255, Centre d'Immunologie et des Maladies Infectieuses, 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Patricia Hermand
- Sorbonne Universités, UPMC Université Paris 06, Inserm U 1135, CNRS ERL 8255, Centre d'Immunologie et des Maladies Infectieuses, 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Guy Trambly de Laissardière
- Université de Cergy-Pontoise, CNRS, UMR 8089, Laboratoire de Physique Théorique et Modélisation, 2 Avenue A. Chauvin, F-95302 Cergy-Pontoise, France
| | - Christophe Combadière
- Sorbonne Universités, UPMC Université Paris 06, Inserm U 1135, CNRS ERL 8255, Centre d'Immunologie et des Maladies Infectieuses, 91 Boulevard de l'Hôpital, F-75013 Paris, France
| | - Philippe Deterre
- Sorbonne Universités, UPMC Université Paris 06, Inserm U 1135, CNRS ERL 8255, Centre d'Immunologie et des Maladies Infectieuses, 91 Boulevard de l'Hôpital, F-75013 Paris, France.
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11
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Rossi FW, Napolitano F, Pesapane A, Mascolo M, Staibano S, Matucci-Cerinic M, Guiducci S, Ragno P, di Spigna G, Postiglione L, Marone G, Montuori N, de Paulis A. Upregulation of the N-Formyl Peptide Receptors in Scleroderma Fibroblasts Fosters the Switch to Myofibroblasts. THE JOURNAL OF IMMUNOLOGY 2015; 194:5161-73. [DOI: 10.4049/jimmunol.1402819] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 03/30/2015] [Indexed: 01/11/2023]
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12
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Schlesinger M, Bendas G. Contribution of very late antigen-4 (VLA-4) integrin to cancer progression and metastasis. Cancer Metastasis Rev 2015; 34:575-91. [DOI: 10.1007/s10555-014-9545-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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13
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Abstract
Leukocyte migration through activated venular walls is a fundamental immune response that is prerequisite to the entry of effector cells such as neutrophils, monocytes, and effector T cells to sites of infection, injury, and stress within the interstitium. Stimulation of leukocytes is instrumental in this process with enhanced temporally controlled leukocyte adhesiveness and shape-changes promoting leukocyte attachment to the inner wall of blood vessels under hydrodynamic forces. This initiates polarized motility of leukocytes within and through venular walls and transient barrier disruption facilitated sequentially by stimulated vascular cells, i.e., endothelial cells and their associated pericytes. Perivascular cells such as macrophages and mast cells that act as tissue inflammatory sentinels can also directly and indirectly regulate the exit of leukocytes from the vascular lumen. In this review, we discuss current knowledge and open questions regarding the mechanisms involved in the interactions of different effector leukocytes with peripheral vessels in extralymphoid organs.
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Affiliation(s)
- Sussan Nourshargh
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
| | - Ronen Alon
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100 Israel.
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14
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Chigaev A, Smagley Y, Haynes MK, Ursu O, Bologa CG, Halip L, Oprea T, Waller A, Carter MB, Zhang Y, Wang W, Buranda T, Sklar LA. FRET detection of lymphocyte function-associated antigen-1 conformational extension. Mol Biol Cell 2014; 26:43-54. [PMID: 25378583 PMCID: PMC4279228 DOI: 10.1091/mbc.e14-06-1050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Lymphocyte function–associated antigen 1 (LFA-1) and its ligands are essential for immune cell interactions. LFA-1 is regulated through conformational changes. The relationship between molecular conformation and function is unclear. Förster resonance energy transfer is used to assess LFA-1 conformation under real-time signaling conditions. Lymphocyte function–associated antigen 1 (LFA-1, CD11a/CD18, αLβ2-integrin) and its ligands are essential for adhesion between T-cells and antigen-presenting cells, formation of the immunological synapse, and other immune cell interactions. LFA-1 function is regulated through conformational changes that include the modulation of ligand binding affinity and molecular extension. However, the relationship between molecular conformation and function is unclear. Here fluorescence resonance energy transfer (FRET) with new LFA-1–specific fluorescent probes showed that triggering of the pathway used for T-cell activation induced rapid unquenching of the FRET signal consistent with extension of the molecule. Analysis of the FRET quenching at rest revealed an unexpected result that can be interpreted as a previously unknown LFA-1 conformation.
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Affiliation(s)
| | | | - Mark K Haynes
- University of New Mexico Center for Molecular Discovery, and
| | - Oleg Ursu
- University of New Mexico Center for Molecular Discovery, and Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Cristian G Bologa
- University of New Mexico Center for Molecular Discovery, and Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Liliana Halip
- Department of Computational Chemistry, Institute of Chemistry, Romanian Academy, Timisoara 300223, Romania
| | - Tudor Oprea
- University of New Mexico Center for Molecular Discovery, and Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Anna Waller
- University of New Mexico Center for Molecular Discovery, and
| | - Mark B Carter
- University of New Mexico Center for Molecular Discovery, and
| | - Yinan Zhang
- Department of Pharmaceutical Science, College of Pharmacy, University of Kentucky, Lexington, KY 40506
| | - Wei Wang
- Department of Chemistry, University of New Mexico, Albuquerque, NM 87131
| | | | - Larry A Sklar
- Department of Pathology and Cancer Center, University of New Mexico Center for Molecular Discovery, and
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15
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Chigaev A, Smagley Y, Sklar LA. Carbon monoxide down-regulates α4β1 integrin-specific ligand binding and cell adhesion: a possible mechanism for cell mobilization. BMC Immunol 2014; 15:52. [PMID: 25367365 PMCID: PMC4221689 DOI: 10.1186/s12865-014-0052-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/21/2014] [Indexed: 01/13/2023] Open
Abstract
Background Carbon monoxide (CO), a byproduct of heme degradation, is attracting growing attention from the scientific community. At physiological concentrations, CO plays a role as a signal messenger that regulates a number of physiological processes. CO releasing molecules are under evaluation in preclinical models for the management of inflammation, sepsis, ischemia/reperfusion injury, and organ transplantation. Because of our discovery that nitric oxide signaling actively down-regulates integrin affinity and cell adhesion, and the similarity between nitric oxide and CO-dependent signaling, we studied the effects of CO on integrin signaling and cell adhesion. Results We used a cell permeable CO releasing molecule (CORM-2) to elevate intracellular CO, and a fluorescent Very Late Antigen-4 (VLA-4, α4β1-integrin)-specific ligand to evaluate the integrin state in real-time on live cells. We show that the binding of the ligand can be rapidly down-modulated in resting cells and after inside-out activation through several Gαi-coupled receptors. Moreover, cell treatment with hemin, a natural source of CO, resulted in comparable VLA-4 ligand dissociation. Inhibition of VLA-4 ligand binding by CO had a dramatic effect on cell-cell interaction in a VLA-4/VCAM-1-dependent cell adhesion system. Conclusions We conclude that the CO signaling pathway can rapidly down-modulate binding of the VLA-4 -specific ligand. We propose that CO-regulated integrin deactivation provides a basis for modulation of immune cell adhesion as well as rapid cell mobilization, for example as shown for splenic monocytes in response to surgically induced ischemia of the myocardium.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and University of New Mexico Cancer Center, Albuquerque 87131, NM, USA.
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16
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Differential TNF production by monocyte subsets under physical stress: blunted mobilization of proinflammatory monocytes in prehypertensive individuals. Brain Behav Immun 2013; 27:101-8. [PMID: 23046723 PMCID: PMC3518602 DOI: 10.1016/j.bbi.2012.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 09/25/2012] [Accepted: 10/01/2012] [Indexed: 01/12/2023] Open
Abstract
Elevated blood pressure (BP) and infiltration of the vasculature by monocytes contribute to vascular pathology; but, monocyte migratory characteristics based on differing inflammatory potential under adrenergic activation remains unclear. We compared nonclassical (CD14(+)CD16(++); HLA-DR(+)), intermediate (CD14(++)CD16(+); HLA-DR(++)), and classical (CD14(++)CD16(-); HLA-DR(+/-)) monocyte trafficking and their LPS-stimulated TNF production in response to a physical stressor (20-min treadmill exercise at 65-70% VO(2peak)) in participants with high prehypertension (PHT), mild PHT or normal BP (NBP). To determine adrenergic receptor (AR) sensitivity, pre-exercise cells were also treated with isoproterenol (Iso). When cells were stimulated with LPS, the CD16 molecules were downregulated, and monocyte subsets were differentiated based on HLA-DR expression. Monocyte subpopulations (as % of total monocytes) and intracellular TNF production were evaluated by flow cytometry. TNF production in all subsets decreased post-exercise and with ex-vivo incubation with Iso, irrespective of BP (p<0.001), with nonclassical and intermediate monocytes being a major source of TNF production. Overall, % nonclassical monocytes increased, % intermediate did not change, whereas % classical decreased post-exercise (p<0.001). However, % increase in nonclassical monocytes under exercise-induced adrenergic activation was blunted in high PHT individuals (p<0.05), but not in individuals with mild PHT and NBP. These findings extend our previous reports by showing that the mobilization of proinflammatory monocytes under physical stress is attenuated with even mild BP elevation. This may be indicative of monocytic AR desensitization and/or greater adhesion of "proinflammatory" monocytes to the vascular endothelium in hypertension with potential clinical implications of vascular pathology.
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17
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Chigaev A, Sklar LA. Aspects of VLA-4 and LFA-1 regulation that may contribute to rolling and firm adhesion. Front Immunol 2012; 3:242. [PMID: 22876249 PMCID: PMC3410440 DOI: 10.3389/fimmu.2012.00242] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 07/18/2012] [Indexed: 01/21/2023] Open
Abstract
Very Late Antigen-4 (CD49d/CD29, alpha4 beta1) and Lymphocyte Function-associated Antigen-1 (CD11a/CD18, alphaL beta2) integrins are representatives of a large family of adhesion receptors widely expressed on immune cells. They participate in cell recruitment to sites of inflammation, as well as multiple immune cell interactions. A unique feature of integrins is that integrin-dependent cell adhesion can be rapidly and reversibly modulated in response to cell signaling, because of a series of conformational changes within the molecule, which include changes in the affinity of the ligand binding pocket, molecular extension (unbending) and others. Here, we provide a concise comparative analysis of the conformational regulation of the two integrins with specific attention to the physiological differences between these molecules. We focus on recent data obtained using a novel technology, based on small fluorescent ligand-mimicking probes for the detection of integrin conformation in real-time on live cells at natural receptor abundance.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque NM, USA
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18
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Abstract
Integrins play critical adhesion and signaling roles during development, wound healing, immunity, and cancer. Central to their function is a unique ability to dynamically modulate their adhesiveness and signaling properties through changes in conformation, both homo- and heterotypic protein-protein interactions and cellular distribution. Genetic, biochemical and structural studies have been instrumental in uncovering overall functions, describing ligand and regulatory protein interactions and elucidating the molecular architecture of integrins. However, such approaches alone are inadequate to describe how dynamic integrin behaviors are orchestrated in intact cells. To fill this void, a wide array of distinct light microscopy (largely fluorescence-based) imaging approaches have been developed and employed. Various microscopy technologies, including wide-field, optical sectioning (laser-scanning confocal, spinning-disk confocal, and multiphoton), TIRF and range of novel "Super-Resolution" techniques have been used in combination with diverse imaging modalities (such as IRM, FRET, FRAP, CALI, and fluorescence speckle imaging) to address distinct aspects of integrin function and regulation. This chapter provides an overview of these imaging approaches and how they have advanced our understanding of integrins.
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Affiliation(s)
- Christopher V Carman
- Center for Vascular Biology Research, Division of Molecular and Vascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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19
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Abstract
Interaction of the integrin receptors with ligands determines the molecular basis of integrin-dependent cell adhesion. Integrin ligands are typically large proteins with relatively low binding affinities. This makes direct ligand-binding kinetic measurements somewhat difficult. Here we examine several real-time methods, aimed to overcome these experimental limitations and to distinguish the regulation of integrin conformation and affinity. This chapter includes: the use of a small ligand-mimetic probe for studies of inside-out regulation of integrin affinity and unbending, real-time cell aggregation and disaggregation kinetics to probe integrin conformational states and the number of integrin-ligand bonds, as well as the real-time monitoring of ligand-induced epitopes under signaling through G-protein-coupled receptors, and others. Experimental data obtained using these novel methods are summarized in terms of the current model of integrin activation.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
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20
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Chemokine triggered integrin activation and actin remodeling events guiding lymphocyte migration across vascular barriers. Exp Cell Res 2011; 317:632-41. [PMID: 21376176 DOI: 10.1016/j.yexcr.2010.12.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 12/07/2010] [Accepted: 12/07/2010] [Indexed: 01/13/2023]
Abstract
Chemokine signals activate leukocyte integrins and actin remodeling machineries critical for leukocyte adhesion and motility across vascular barriers. The arrest of leukocytes at target blood vessel sites depends on rapid conformational activation of their α4 and β2 integrins by the binding of endothelial-displayed chemokines to leukocyte Gi-protein coupled receptors (GPCRs). A universal regulator of this event is the integrin-actin adaptor, talin1. Chemokine-stimulated GPCRs can transmit within fractions of seconds signals via multiple Rho GTPases, which locally raise plasma membrane levels of the talin activating phosphatidyl inositol, PtdIns(4,5)P2 (PIP2). Additional pools of GPCR stimulated Rac-1 and Rap-1 GTPases together with GPCR stimulated PLC and PI3K family members regulate the turnover of focal contacts of leukocyte integrins, induce the collapse of leukocyte microvilli, and promote polarized leukocyte crawling in search of exit cues. Concomitantly, other leukocyte GTPases trigger invasive protrusions into and between endothelial cells in search of basolateral chemokine exit cues. We will review here major findings and open questions related to these sequential guiding activities of endothelial presented chemokines, focusing mainly on lymphocyte-endothelial interactions as a paradigm for other leukocytes.
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21
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Chigaev A, Smagley Y, Sklar LA. Nitric oxide/cGMP pathway signaling actively down-regulates α4β1-integrin affinity: an unexpected mechanism for inducing cell de-adhesion. BMC Immunol 2011; 12:28. [PMID: 21586157 PMCID: PMC3125286 DOI: 10.1186/1471-2172-12-28] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 05/17/2011] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Integrin activation in response to inside-out signaling serves as the basis for rapid leukocyte arrest on endothelium, migration, and mobilization of immune cells. Integrin-dependent adhesion is controlled by the conformational state of the molecule, which is regulated by seven-transmembrane Guanine nucleotide binding Protein-Coupled Receptors (GPCRs). α4β1-integrin (CD49d/CD29, Very Late Antigen-4, VLA-4) is expressed on leukocytes, hematopoietic progenitors, stem cells, hematopoietic cancer cells, and others. VLA-4 conformation is rapidly up-regulated by inside-out signaling through Gαi-coupled GPCRs and down-regulated by Gαs-coupled GPCRs. However, other signaling pathways, which include nitric oxide-dependent signaling, have been implicated in the regulation of cell adhesion. The goal of the current report was to study the effect of nitric oxide/cGMP signaling pathway on VLA-4 conformational regulation. RESULTS Using fluorescent ligand binding to evaluate the integrin activation state on live cells in real-time, we show that several small molecules, which specifically modulate nitric oxide/cGMP signaling pathway, as well as a cell permeable cGMP analog, can rapidly down-modulate binding of a VLA-4 specific ligand on cells pre-activated through three Gαi-coupled receptors: wild type CXCR4, CXCR2 (IL-8RB), and a non-desensitizing mutant of formyl peptide receptor (FPR ΔST). Upon signaling, we detected rapid changes in the ligand dissociation rate. The dissociation rate after inside-out integrin de-activation was similar to the rate for resting cells. In a VLA-4/VCAM-1-specific myeloid cell adhesion system, inhibition of the VLA-4 affinity change by nitric oxide had a statistically significant effect on real-time cell aggregation. CONCLUSIONS We conclude that nitric oxide/cGMP signaling pathway can rapidly down-modulate the affinity state of the VLA-4 binding pocket, especially under the condition of sustained Gαi-coupled GPCR signaling, generated by a non-desensitizing receptor mutant. This suggests a fundamental role of this pathway in de-activation of integrin-dependent cell adhesion.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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22
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Chigaev A, Smagley Y, Zhang Y, Waller A, Haynes MK, Amit O, Wang W, Larson RS, Sklar LA. Real-time analysis of the inside-out regulation of lymphocyte function-associated antigen-1 revealed similarities to and differences from very late antigen-4. J Biol Chem 2011; 286:20375-86. [PMID: 21515675 PMCID: PMC3121518 DOI: 10.1074/jbc.m110.206185] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Ten years ago, we introduced a fluorescent probe that shed light on the inside-out regulation of one of the major leukocyte integrins, very late antigen-4 (VLA-4, CD49d/CD29). Here we describe the regulation of another leukocyte integrin, lymphocyte function-associated antigen-1 (LFA-1, CD11a/CD18) using a novel small fluorescent probe in real time on live cells. We found that multiple signaling mechanisms regulate LFA-1 conformation in a manner analogous to VLA-4. LFA-1 can be rapidly activated by Gαi-coupled G protein-coupled receptors (GPCRs) and deactivated by Gαs-coupled GPCRs. The effects of Gαs-coupled GPCR agonists can be reversed in real time by receptor-specific antagonists. The specificity of the fluorescent probe binding has been assessed in a competition assay using the natural LFA-1 ligand ICAM-1 and the LFA-1-specific α I allosteric antagonist BIRT0377. Similar to VLA-4 integrin, modulation of the ligand dissociation rate can be observed for different LFA-1 affinity states. However, we also found a striking difference in the binding of the small fluorescent ligand. In the absence of inside-out activation ligand, binding to LFA-1 is extremely slow, at least 10 times slower than expected for diffusion-limited binding. This implies that an additional structural mechanism prevents ligand binding to inactive LFA-1. We propose that such a mechanism explains the inability of LFA-1 to support cell rolling, where the absence of its rapid engagement by a counterstructure in the inactive state leads to a requirement for a selectin-mediated rolling step.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA.
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23
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Chigaev A, Wu Y, Williams DB, Smagley Y, Sklar LA. Discovery of very late antigen-4 (VLA-4, alpha4beta1 integrin) allosteric antagonists. J Biol Chem 2011; 286:5455-63. [PMID: 21131351 PMCID: PMC3037658 DOI: 10.1074/jbc.m110.162636] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 11/19/2010] [Indexed: 11/06/2022] Open
Abstract
Integrins are cell adhesion receptors that mediate cell-to-cell, or cell-to-extracellular matrix adhesion. They represent an attractive target for treatment of multiple diseases. Two classes of small molecule integrin inhibitors have been developed. Competitive antagonists bind directly to the integrin ligand binding pocket and thus disrupt the ligand-receptor interaction. Allosteric antagonists have been developed primarily for α(L)β(2)- integrin (LFA-1, lymphocyte function-associated antigen-1). Here we present the results of screening the Prestwick Chemical Library using a recently developed assay for the detection of α(4)β(1)-integrin allosteric antagonists. Secondary assays confirmed that the compounds identified: 1) do not behave like competitive (direct) antagonists; 2) decrease ligand binding affinity for VLA-4 ∼2 orders of magnitude; 3) exhibit antagonistic properties at low temperature. In a cell based adhesion assay in vitro, the compounds rapidly disrupted cellular aggregates. In accord with reports that VLA-4 antagonists in vivo induce mobilization of hematopoietic progenitors into the peripheral blood, we found that administration of one of the compounds significantly increased the number of colony-forming units in mice. This effect was comparable to AMD3100, a well known progenitor mobilizing agent. Because all the identified compounds are structurally related, previously used, or currently marketed drugs, this result opens a range of therapeutic possibilities for VLA-4-related pathologies.
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Affiliation(s)
- Alexandre Chigaev
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Yang Wu
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - D. Bart Williams
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Yelena Smagley
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Larry A. Sklar
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
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24
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Zwartz GJ, Chigaev A, Foutz TD, Edwards B, Sklar LA. A miniature Couette to generate shear for flow cytometry: studying real-time modulation of intracellular calcium in monocytic cells. Cytometry A 2011; 79:233-40. [PMID: 22045643 DOI: 10.1002/cyto.a.21027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 12/17/2010] [Accepted: 01/03/2011] [Indexed: 11/07/2022]
Abstract
Extracellular hydrodynamic forces may be transmitted to the interior of cells through the alteration of integrin conformation and affinity. Integrin activation regulates leukocyte recruitment, cell activation, and transmigration. The cellular and molecular mechanisms for integrin activation are not precisely known, although intracellular calcium signaling is involved. Flow cytometry offers a versatile way to study intracellular calcium signaling in real-time. We report a novel method to generate defined shear by using a miniature Couette. Testing involved measuring shear-induced intracellular calcium signals of human monoblastoid U937 cells in suspension. The Couette was connected externally to a flow cytometer and pressurized at 6 PSI (4.1 N/m(2) ). Cells were subjected to a well-defined shear between 0 and 1,000 s(-1) and delivered continuously within 10 s to a FACScan at 1 μl/s. Intracellular calcium levels and the percentage of cells activated increased as shear increased in duration and intensity.
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Affiliation(s)
- Gordon J Zwartz
- Department of Physics, University of New Mexico Health Science Center, Albuquerque, NM 87131, USA.
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25
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Abstract
Interaction of the integrin receptors with ligands determines the molecular basis of integrin-dependent cell adhesion. Integrin ligands are typically large proteins with relatively low binding affinities. This makes direct ligand-binding kinetic measurements somewhat difficult. Here we examine several real-time methods, aimed to overcome these experimental limitations and to distinguish the regulation of integrin conformation and affinity. This chapter includes: the use of a small ligand-mimetic probe for studies of inside-out regulation of integrin affinity and unbending, real-time cell aggregation and disaggregation kinetics to probe integrin conformational states and the number of integrin-ligand bonds, as well as the real-time monitoring of ligand-induced epitopes under signaling through G-protein-coupled receptors, and others. Experimental data obtained using these novel methods are summarized in terms of the current model of integrin activation.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
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26
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Cunningham BT. Photonic Crystal Surfaces as a General Purpose Platform for Label-Free and Fluorescent Assays. ACTA ACUST UNITED AC 2010; 15:120-135. [PMID: 20383277 DOI: 10.1016/j.jala.2009.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Photonic crystal surfaces can be designed to provide a wide range of functions that are used to perform biochemical and cell-based assays. Detection of the optical resonant reflections from photonic crystal surfaces enables high sensitivity label-free biosensing, while the enhanced electromagnetic fields that occur at resonant wavelengths can be used to enhance the detection sensitivity of any surface-based fluorescence assay. Fabrication of photonic crystals from inexpensive plastic materials over large surface areas enables them to be incorporated into standard formats that include microplates, microarrays, and microfluidic channels. This report reviews the design of photonic crystal biosensors, their associated detection instrumentation, and biological applications. Applications including small molecule high throughput screening, cell membrane integrin activation, gene expression analysis, and protein biomarker detection are highlighted. Recent results in which photonic crystal surfaces are used for enhancing the detection of Surface-Enhanced Raman Spectroscopy, and the development of high resolution photonic crystal-based laser biosensors are also described.
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Affiliation(s)
- Brian T Cunningham
- Department of Electrical and Computer Engineering Department of Bioengineering University of Illinois at Urbana-Champaign
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27
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Dimitrov S, Lange T, Born J. Selective mobilization of cytotoxic leukocytes by epinephrine. THE JOURNAL OF IMMUNOLOGY 2009; 184:503-11. [PMID: 19949113 DOI: 10.4049/jimmunol.0902189] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
It is well-known that acute stress, presumably as a first defense against pathogens, enhances PBMC counts by mobilizing these beta2-adrenoceptor positive cells from the marginal pool. Yet, only select leukocyte subsets participate in this phenomenon of adrenergic leukocytosis and underlying mechanisms are obscure. In this study, we analyzed in human blood adhesion molecule and chemokine receptor profiles in 14 leukocyte subsets, and responsiveness of subsets to epinephrine in vivo and in vitro. Five subsets, namely, CCR7(-)CD45RA(+)CD8(+) effector T cells, CD4(-)CD8(-) gamma/delta T cells, CD3(+)CD56(+) NKT-like cells, CD16(+)CD56(dim) cytotoxic NK cells, and CD14(dim)CD16(+) proinflammatory monocytes showed a rapid and transient increase after infusion of epinephrine at physiological concentrations. These cells were characterized by a CD62L(-)CD11a(bright)CX3CR(bright) phenotype, whereby expression of both CD11a and CX3CR1 was strongly correlated with adrenergic leukocytosis in vivo (r = 0.86 and 0.78, p < 0.005). The same subsets showed highest adherence to activated endothelium in vitro, which (except for proinflammatory monocytes) was reversed by epinephrine. We conclude that these five cytotoxic effector leukocyte subsets comprise the marginal pool by a CD11a/CX3CR1-mediated attachment to the endothelium. Epinephrine rapidly attenuates this attachment to allow demargination and release of the cells into the circulation that, because of their cytotoxic effector function, provide immediate protection from invading pathogens.
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Affiliation(s)
- Stoyan Dimitrov
- Department of Neuroendocrinology, University of Lübeck, Lübeck, Germany
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28
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Njus BH, Chigaev A, Waller A, Wlodek D, Ostopovici-Halip L, Ursu O, Wang W, Oprea TI, Bologa CG, Sklar LA. Conformational mAb as a tool for integrin ligand discovery. Assay Drug Dev Technol 2009; 7:507-15. [PMID: 19754304 PMCID: PMC3096548 DOI: 10.1089/adt.2009.0203] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
alpha(4)beta(1)-Integrin (very late antigen-4 (VLA-4)) mediates cell adhesion to cell surface ligands (VCAM-1). Binding of VLA-4 to VCAM-1 initiates rolling and firm adhesion of leukocytes to vascular endothelium followed by the extravasation into the tissue. VLA-4-dependent adhesion plays a key role in controlling leukocyte adhesive events. Small molecules that bind to the integrin ligand-binding site and block its interaction with natural ligands represent promising candidates for treatment of several diseases. Following a flow cytometric screen for small molecule discovery, we took advantage of a conformationally sensitive anti-beta(1)-integrin antibody (HUTS-21) and a small LDV-containing ligand (LDV-FITC) with known affinity to study binding affinities of several known and recently discovered integrin ligands. We found that binding of the LDV-containing small molecule induced exposure of HUTS-21 epitope and that the EC(50) for antibody binding was equal to previously reported K(d) for fluorescent LDV (LDV-FITC). Thus, binding of HUTS-21 can be used to report ligand-binding site occupancy. We studied binding of two known integrin ligands (YLDV and TR14035), as well as of two novel compounds. EC(50) values for HUTS-21 binding showed good correlation with K(i)s determined in the competition assay with LDV-FITC for all ligands. A docking model suggests a common mode of binding for the small molecule VLA-4 ligands. This novel approach described here can be used to determine ligand-binding affinities for unlabeled integrin ligands, and can be adapted to a high-throughput screening format for identification of unknown integrin ligands.
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Affiliation(s)
- Ben H. Njus
- Department of Chemistry, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Anna Waller
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Danuta Wlodek
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Liliana Ostopovici-Halip
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
- Romanian Academy—Institute of Chemistry, Timisoara, Romania.
| | - Oleg Ursu
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Wei Wang
- Department of Chemistry, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Tudor I. Oprea
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Cristian G. Bologa
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
| | - Larry A. Sklar
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico.
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Abstract
Pronounced circadian rhythms in numbers of circulating T cells reflect a systemic control of adaptive immunity whose mechanisms are obscure. Here, we show that circadian variations in T cell subpopulations in human blood are differentially regulated via release of cortisol and catecholamines. Within the CD4(+) and CD8(+) T cell subsets, naive cells show pronounced circadian rhythms with a daytime nadir, whereas (terminally differentiated) effector CD8(+) T cell counts peak during daytime. Naive T cells were negatively correlated with cortisol rhythms, decreased after low-dose cortisol infusion, and showed highest expression of CXCR4, which was up-regulated by cortisol. Effector CD8(+) T cells were positively correlated with epinephrine rhythms, increased after low-dose epinephrine infusion, and showed highest expression of beta-adrenergic and fractalkine receptors (CX3CR1). Daytime increases in cortisol via CXCR4 probably act to redistribute naive T cells to bone marrow, whereas daytime increases in catecholamines via beta-adrenoceptors and, possibly, a suppression of fractalkine signaling promote mobilization of effector CD8(+) T cells from the marginal pool. Thus, activation of the major stress hormones during daytime favor immediate effector defense but diminish capabilities for initiating adaptive immune responses.
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Chigaev A, Waller A, Amit O, Halip L, Bologa CG, Sklar LA. Real-time analysis of conformation-sensitive antibody binding provides new insights into integrin conformational regulation. J Biol Chem 2009; 284:14337-46. [PMID: 19251697 PMCID: PMC2682882 DOI: 10.1074/jbc.m901178200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Integrins are heterodimeric adhesion receptors that regulate immune cell
adhesion. Integrin-dependent adhesion is controlled by multiple conformational
states that include states with different affinity to the ligand, states with
various degrees of molecule unbending, and others. Affinity change and
molecule unbending play major roles in the regulation of cell adhesion. The
relationship between different conformational states of the integrin is
unclear. Here we have used conformationally sensitive antibodies and a small
LDV-containing ligand to study the role of the inside-out signaling through
formyl peptide receptor and CXCR4 in the regulation of
α4β1 integrin conformation. We found that in
the absence of ligand, activation by formyl peptide or SDF-1 did not result in
a significant exposure of HUTS-21 epitope. Occupancy of the ligand binding
pocket without cell activation was sufficient to induce epitope exposure.
EC50 for HUTS-21 binding in the presence of LDV was identical to a
previously reported ligand equilibrium dissociation constant at rest and after
activation. Furthermore, the rate of HUTS-21 binding was also related to the
VLA-4 activation state even at saturating ligand concentration. We propose
that the unbending of the integrin molecule after guanine nucleotide-binding
protein-coupled receptor-induced signaling accounts for the enhanced rate of
HUTS-21 binding. Taken together, current results support the existence of
multiple conformational states independently regulated by both inside-out
signaling and ligand binding. Our data suggest that VLA-4 integrin hybrid
domain movement does not depend on the affinity state of the ligand binding
pocket.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA.
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Lefort CT, Kim M. Chapter 12 Fluorescence Resonance Energy Transfer in the Studies of Integrin Activation. CURRENT TOPICS IN MEMBRANES 2009. [DOI: 10.1016/s1063-5823(09)64012-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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