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Vizcarra EA, Ulu A, Landrith TA, Qiu X, Godzik A, Wilson EH. Group 1 metabotropic glutamate receptor expression defines a T cell memory population during chronic Toxoplasma infection that enhances IFN-gamma and perforin production in the CNS. Brain Behav Immun 2023; 114:131-143. [PMID: 37604212 DOI: 10.1016/j.bbi.2023.08.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 08/23/2023] Open
Abstract
Within the brain, a pro-inflammatory response is essential to prevent clinical disease due to Toxoplasma gondii reactivation. Infection in the immunocompromised leads to lethal Toxoplasmic encephalitis while in the immunocompetent, there is persistent low-grade inflammation which is devoid of clinical symptoms. This signifies that there is a well-balanced and regulated inflammatory response to T. gondii in the brain. T cells are the dominant immune cells that prevent clinical disease, and this is mediated through the secretion of effector molecules such as perforins and IFN-γ. The presence of cognate antigen, the expression of survival cytokines, and the alteration of the epigenetic landscape drive the development of memory T cells. However, specific extrinsic signals that promote the formation and maintenance of memory T cells within tissue are poorly understood. During chronic infection, there is an increase in extracellular glutamate that, due to its function as an excitatory neurotransmitter, is normally tightly controlled in the CNS. Here we demonstrate that CD8+ T cells from the T. gondii-infected brain parenchyma are enriched for metabotropic glutamate receptors (mGluR's). Characterization studies determined that mGluR+ expression by CD8+ T cells defines a distinct memory population at the transcriptional and protein level. Finally, using receptor antagonists and agonists we demonstrate mGluR signaling is required for optimal CD8+ T cell production of the effector cytokine IFNγ. This work suggests that glutamate is an important environmental signal of inflammation that promotes T cell function. Understanding glutamate's influence on T cells in the brain can provide insights into the mechanisms that govern protective immunity against CNS-infiltrating pathogens and neuroinflammation.
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Affiliation(s)
- Edward A Vizcarra
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, United States
| | - Arzu Ulu
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, United States
| | - Tyler A Landrith
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, United States
| | - Xinru Qiu
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, United States
| | - Adam Godzik
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, United States
| | - Emma H Wilson
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, United States.
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2
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Vizcarra EA, Goerner AL, Ulu A, Hong DD, Bergersen KV, Talavera MA, Le Roch K, Wilson EH, White MW. An ex vivo model of Toxoplasma recrudescence reveals developmental plasticity of the bradyzoite stage. mBio 2023; 14:e0183623. [PMID: 37675999 PMCID: PMC10653814 DOI: 10.1128/mbio.01836-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 09/08/2023] Open
Abstract
IMPORTANCE The classical depiction of the Toxoplasma lifecycle is bradyzoite excystation conversion to tachyzoites, cell lysis, and immune control, followed by the reestablishment of bradyzoites and cysts. In contrast, we show that tachyzoite growth slows independent of the host immune response at a predictable time point following excystation. Furthermore, we demonstrate a host cell-dependent pathway of continuous amplification of the cyst-forming bradyzoite population. The developmental plasticity of the excysted bradyzoites further underlines the critical role the cyst plays in the flexibility of the lifecycle of this ubiquitous parasite. This revised model of Toxoplasma recrudescence uncovers previously unknown complexity in the clinically important bradyzoite stage of the parasite, which opens the door to further study these novel developmental features of the Toxoplasma intermediate life cycle.
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Affiliation(s)
- Edward A. Vizcarra
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California, USA
| | - Amber L. Goerner
- Division of Infectious Disease and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Arzu Ulu
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California, USA
| | - David D. Hong
- Division of Infectious Disease and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Kristina V. Bergersen
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California, USA
| | - Michael A. Talavera
- Division of Infectious Disease and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Karine Le Roch
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, California, USA
| | - Emma H. Wilson
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California, USA
| | - Michael W. White
- Division of Infectious Disease and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
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3
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Agnew-Svoboda W, Ubina T, Figueroa Z, Wong YC, Vizcarra EA, Roebini B, Wilson EH, Fiacco TA, Riccomagno MM. A genetic tool for the longitudinal study of a subset of post-inflammatory reactive astrocytes. Cell Rep Methods 2022; 2:100276. [PMID: 36046623 PMCID: PMC9421582 DOI: 10.1016/j.crmeth.2022.100276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 06/01/2022] [Accepted: 07/22/2022] [Indexed: 11/29/2022]
Abstract
Astrocytes are vital support cells that ensure proper brain function. In brain disease, astrocytes reprogram into a reactive state that alters many of their cellular roles. A long-standing question in the field is whether downregulation of reactive astrocyte (RA) markers during resolution of inflammation is because these astrocytes revert back to a non-reactive state or die and are replaced. This has proven difficult to answer mainly because existing genetic tools cannot distinguish between healthy versus RAs. Here we describe the generation of an inducible genetic tool that can be used to specifically target and label a subset of RAs. Longitudinal analysis of an acute inflammation model using this tool revealed that the previously observed downregulation of RA markers after inflammation is likely due to changes in gene expression and not because of cell death. Our findings suggest that cellular changes associated with astrogliosis after acute inflammation are largely reversible.
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Affiliation(s)
- William Agnew-Svoboda
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Teresa Ubina
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Zoe Figueroa
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Yiu-Cheung Wong
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Edward A. Vizcarra
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA 92521, USA
- Biomedical Sciences Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Bryan Roebini
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Emma H. Wilson
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA 92521, USA
- Biomedical Sciences Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Todd A. Fiacco
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, Riverside, CA 92521, USA
- Biomedical Sciences Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Martin M. Riccomagno
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, Riverside, CA 92521, USA
- Biomedical Sciences Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
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4
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Carlin AF, Wen J, Vizcarra EA, McCauley M, Chaillon A, Akrami K, Kim C, Ngono AE, Lara-Marquez ML, Smith DM, Glass CK, Schooley RT, Benner C, Shresta S. A longitudinal systems immunologic investigation of acute Zika virus infection in an individual infected while traveling to Caracas, Venezuela. PLoS Negl Trop Dis 2018; 12:e0007053. [PMID: 30596671 PMCID: PMC6329527 DOI: 10.1371/journal.pntd.0007053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 01/11/2019] [Accepted: 12/05/2018] [Indexed: 12/29/2022] Open
Abstract
Zika virus (ZIKV) is an emerging mosquito-borne flavivirus linked to devastating neurologic diseases. Immune responses to flaviviruses may be pathogenic or protective. Our understanding of human immune responses to ZIKV in vivo remains limited. Therefore, we performed a longitudinal molecular and phenotypic characterization of innate and adaptive immune responses during an acute ZIKV infection. We found that innate immune transcriptional and genomic responses were both cell type- and time-dependent. While interferon stimulated gene induction was common to all innate immune cells, the upregulation of important inflammatory cytokine genes was primarily limited to monocyte subsets. Additionally, genomic analysis revealed substantial chromatin remodeling at sites containing cell-type specific transcription factor binding motifs that may explain the observed changes in gene expression. In this dengue virus-experienced individual, adaptive immune responses were rapidly mobilized with T cell transcriptional activity and ZIKV neutralizing antibody responses peaking 6 days after the onset of symptoms. Collectively this study characterizes the development and resolution of an in vivo human immune response to acute ZIKV infection in an individual with pre-existing flavivirus immunity. Zika virus (ZIKV) is an emerging flaviviral infection that causes significant clinical disease. It is estimated that approximately one half of the world’s population is at risk for ZIKV infection. There are only a limited number of studies describing the human immune response to ZIKV infection. Carlin et al. combined conventional and genomic approaches to longitudinally analyze the innate and adaptive immune responses to acute ZIKV infection and its resolution in a person who was infected while traveling in Venezuela during the 2016 ZIKV epidemic year. Genome-wide sequencing in individual cell types revealed that although many populations respond to interferon stimulation, only specific cell populations within peripheral blood mononuclear cells upregulate important inflammatory cytokine gene expression. Additionally, analysis of open chromatin using ATAC-seq suggests that chromatin remodeling at sites containing cell-type specific transcription factor binding motifs may help us understand changes in gene expression. Consistent with previous reports, this individual with prior exposure to dengue virus (DENV), rapidly developed neutralizing anti-ZIKV responses that were cross-reactive with multiple DENV serotypes. Collectively this study combines traditional and genomic approaches to characterize the cell-type specific development of an in vivo human immune response to acute ZIKV infection.
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Affiliation(s)
- Aaron F. Carlin
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
- * E-mail: (AFC); (SS)
| | - Jinsheng Wen
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, California, United States of America
| | - Edward A. Vizcarra
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, California, United States of America
| | - Melanie McCauley
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, California, United States of America
| | - Antoine Chaillon
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States of America
| | - Kevan Akrami
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Cheryl Kim
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, California, United States of America
| | - Annie Elong Ngono
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, California, United States of America
| | - Maria Luz Lara-Marquez
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Davey M. Smith
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
- Veterans Affairs San Diego Healthcare System, San Diego, California, United States of America
| | - Christopher K. Glass
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Robert T. Schooley
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Christopher Benner
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Sujan Shresta
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, California, United States of America
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, California, United States of America
- * E-mail: (AFC); (SS)
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5
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Carlin AF, Plummer EM, Vizcarra EA, Sheets N, Joo Y, Tang W, Day J, Greenbaum J, Glass CK, Diamond MS, Shresta S. An IRF-3-, IRF-5-, and IRF-7-Independent Pathway of Dengue Viral Resistance Utilizes IRF-1 to Stimulate Type I and II Interferon Responses. Cell Rep 2018; 21:1600-1612. [PMID: 29117564 DOI: 10.1016/j.celrep.2017.10.054] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 07/25/2017] [Accepted: 10/13/2017] [Indexed: 01/19/2023] Open
Abstract
Interferon-regulatory factors (IRFs) are a family of transcription factors (TFs) that translate viral recognition into antiviral responses, including type I interferon (IFN) production. Dengue virus (DENV) and other clinically important flaviviruses are suppressed by type I IFN. While mice lacking the type I IFN receptor (Ifnar1-/-) succumb to DENV infection, we found that mice deficient in three transcription factors controlling type I IFN production (Irf3-/-Irf5-/-Irf7-/- triple knockout [TKO]) survive DENV challenge. DENV infection of TKO mice resulted in minimal type I IFN production but a robust type II IFN (IFN-γ) response. Using loss-of-function approaches for various molecules, we demonstrate that the IRF-3-, IRF-5-, IRF-7-independent pathway predominantly utilizes IFN-γ and, to a lesser degree, type I IFNs. This pathway signals via IRF-1 to stimulate interleukin-12 (IL-12) production and IFN-γ response. These results reveal a key antiviral role for IRF-1 by activating both type I and II IFN responses during DENV infection.
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Affiliation(s)
- Aaron F Carlin
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Emily M Plummer
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA, USA
| | - Edward A Vizcarra
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA, USA
| | - Nicholas Sheets
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA, USA
| | - Yunichel Joo
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA, USA
| | - William Tang
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA, USA
| | - Jeremy Day
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA, USA
| | - Jay Greenbaum
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA, USA
| | - Christopher K Glass
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Michael S Diamond
- Departments of Medicine, Pathology and Immunology, and Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sujan Shresta
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, CA, USA.
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6
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Ngono AE, Vizcarra EA, Tang WW, Sheets N, Joo Y, Kim K, Gorman MJ, Diamond MS, Shresta S. Investigation of CD8+ T Cell Immunity in Zika Virus Infection Using Mouse Models. The Journal of Immunology 2017. [DOI: 10.4049/jimmunol.198.supp.78.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
CD8+ T cells may play a dual role in both protection against and pathogenesis of Flaviviruses, including Zika virus (ZIKV). However, virtually nothing is currently known about the role CD8+ T cells play during ZIKV infection in humans and animal models. The goal of our study is to investigate the role of CD8+ T cells during primary ZIKV infection in mice. Using LysMCre+IFNARfl/fl C57BL/6 (H-2b) mice that lack type I IFN receptor in a subset of myeloid cells, we characterized a new mouse model susceptible to infection with both East African lineage (MR766) and Asian lineage (FSS13025) ZIKV strains. A screening of 244 ZIKV epitopes predicted to bind H-2b class I molecules, defined a specific map of 26 and 15 peptides for MR766 and FSS13025 ZIKV strains, respectively. Intracellular cytokine staining confirmed the identity of these epitopes and demonstrated induction of polyfunctional ZIKV-specific CD8+ T cells. Furthermore, adoptive transfer of ZIKV-immune CD8+ T cells reduced viral burdens, whereas depletion of CD8+ T cells led to higher tissue burdens and mortality was increased in ZIKV-infected CD8−/− mice compared to Wild-type. These results demonstrate that CD8+ T cells are important mediators of protection during primary ZIKV infection and provide a H-2b mouse model for investigating ZIKV-specific CD8+ T cell responses. Based on these findings, studies are in progress towards defining the role of resident memory CD8+ T cells in protection against ZIKV infection using our recently developed mouse models of ZIKV systemic infection and sexual transmission.
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Affiliation(s)
| | | | | | | | | | | | - Matthew J Gorman
- 2Department of Medicine, Molecular Microbiology, Pathology, and Immunology, Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael S Diamond
- 2Department of Medicine, Molecular Microbiology, Pathology, and Immunology, Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA
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7
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Elong Ngono A, Vizcarra EA, Tang WW, Sheets N, Joo Y, Kim K, Gorman MJ, Diamond MS, Shresta S. Mapping and Role of the CD8 + T Cell Response During Primary Zika Virus Infection in Mice. Cell Host Microbe 2017; 21:35-46. [PMID: 28081442 PMCID: PMC5234855 DOI: 10.1016/j.chom.2016.12.010] [Citation(s) in RCA: 192] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/15/2016] [Accepted: 12/15/2016] [Indexed: 11/26/2022]
Abstract
CD8+ T cells may play a dual role in protection against and pathogenesis of flaviviruses, including Zika virus (ZIKV). We evaluated the CD8+ T cell response in ZIKV-infected LysMCre+IFNARfl/fl C57BL/6 (H-2b) mice lacking the type I interferon receptor in a subset of myeloid cells. In total, 26 and 15 CD8+ T cell-reactive peptides for ZIKV African (MR766) and Asian (FSS13025) lineage strains, respectively, were identified and validated. CD8+ T cells from infected mice were polyfunctional and mediated cytotoxicity. Adoptive transfer of ZIKV-immune CD8+ T cells reduced viral burdens, whereas their depletion led to higher tissue burdens, and CD8-/- mice displayed higher mortality with ZIKV infection. Collectively, these results demonstrate that CD8+ T cells protect against ZIKV infection. Further, this study provides a T cell competent mouse model for investigating ZIKV-specific T cell responses.
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Affiliation(s)
- Annie Elong Ngono
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - Edward A Vizcarra
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - William W Tang
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - Nicholas Sheets
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - Yunichel Joo
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - Kenneth Kim
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - Matthew J Gorman
- Department of Medicine, Molecular Microbiology, Pathology, and Immunology, Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael S Diamond
- Department of Medicine, Molecular Microbiology, Pathology, and Immunology, Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sujan Shresta
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA.
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Abstract
The transcription factor Twist1 induces epithelial-mesenchymal transition and extracellular matrix degradation to promote tumor metastasis. Although Twist1 also plays a role in embryonic vascular development and tumor angiogenesis, the molecular mechanisms that underlie these processes are not as well understood. Here, we report a novel function for Twist1 in modifying the tumor microenvironment to promote progression. We found that expression of Twist1 in human mammary epithelial cells potently promoted angiogenesis. Surprisingly, Twist1 expression did not increase the secretion of the common proangiogenic factors VEGF and basic fibroblast growth factor but rather induced expression of the macrophage chemoattractant CCL2. Attenuation of endogenous Twist1 in vivo blocked macrophage recruitment and angiogenesis, whereas exogenous CCL2 rescued the ability of tumor cells lacking Twist1 to attract macrophages and promote angiogenesis. Macrophage recruitment also was essential for the ability of Twist1-expressing cells to elicit a strong angiogenic response. Together, our findings show that how Twist1 recruits stromal macrophages through CCL2 induction to promote angiogenesis and tumor progression. As Twist1 expression has been associated with poor survival in many human cancers, this finding suggests that anti-CCL2 therapy may offer a rational strategy to treat Twist1-positive metastatic cancers.
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Affiliation(s)
- Janine M Low-Marchelli
- Biomedical Sciences Program, Department of Pharmacology, University of California, San Diego, CA 92093, USA
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