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Nagatake T, Shiogama Y, Inoue A, Kikuta J, Honda T, Tiwari P, Kishi T, Yanagisawa A, Isobe Y, Matsumoto N, Shimojou M, Morimoto S, Suzuki H, Hirata SI, Steneberg P, Edlund H, Aoki J, Arita M, Kiyono H, Yasutomi Y, Ishii M, Kabashima K, Kunisawa J. The 17,18-epoxyeicosatetraenoic acid-G protein-coupled receptor 40 axis ameliorates contact hypersensitivity by inhibiting neutrophil mobility in mice and cynomolgus macaques. J Allergy Clin Immunol 2017; 142:470-484.e12. [PMID: 29288079 DOI: 10.1016/j.jaci.2017.09.053] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 08/02/2017] [Accepted: 09/14/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND Metabolites of eicosapentaenoic acid exert various physiologic actions. 17,18-Epoxyeicosatetraenoic acid (17,18-EpETE) is a recently identified new class of antiallergic and anti-inflammatory lipid metabolite of eicosapentaenoic acid, but its effects on skin inflammation and the underlying mechanisms remain to be investigated. OBJECTIVE We evaluated the effectiveness of 17,18-EpETE for control of contact hypersensitivity in mice and cynomolgus macaques. We further sought to reveal underlying mechanisms by identifying the responsible receptor and cellular target of 17,18-EpETE. METHODS Contact hypersensitivity was induced by topical application of 2,4-dinitrofluorobenzene. Skin inflammation and immune cell populations were analyzed by using flow cytometric, immunohistologic, and quantitative RT-PCR analyses. Neutrophil mobility was examined by means of imaging analysis in vivo and neutrophil culture in vitro. The receptor for 17,18-EpETE was identified by using the TGF-α shedding assay, and the receptor's involvement in the anti-inflammatory effects of 17,18-EpETE was examined by using KO mice and specific inhibitor treatment. RESULTS We found that preventive or therapeutic treatment with 17,18-EpETE ameliorated contact hypersensitivity by inhibiting neutrophil mobility in mice and cynomolgus macaques. 17,18-EpETE was recognized by G protein-coupled receptor (GPR) 40 (also known as free fatty acid receptor 1) and inhibited chemoattractant-induced Rac activation and pseudopod formation in neutrophils. Indeed, the antiallergic inflammatory effect of 17,18-EpETE was abolished in the absence or inhibition of GPR40. CONCLUSION 17,18-EpETE inhibits neutrophil mobility through GPR40 activation, which is a potential therapeutic target to control allergic inflammatory diseases.
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Affiliation(s)
- Takahiro Nagatake
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Yumiko Shiogama
- Laboratory of Immunoregulation and Vaccine Research, Tsukuba Primate Research Center, NIBIOHN, Tsukuba, Japan
| | - Asuka Inoue
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Junichi Kikuta
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Japan
| | - Tetsuya Honda
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Prabha Tiwari
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Takayuki Kishi
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Atsushi Yanagisawa
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Japan
| | - Yosuke Isobe
- Laboratory for Metabolomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Naomi Matsumoto
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Michiko Shimojou
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Sakiko Morimoto
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Japan
| | - Hidehiko Suzuki
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Japan
| | - So-Ichiro Hirata
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Japan; Department of Microbiology and Immunology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Pär Steneberg
- Umea Center for Molecular Medicine, Umea University, Umea, Sweden
| | - Helena Edlund
- Umea Center for Molecular Medicine, Umea University, Umea, Sweden
| | - Junken Aoki
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Makoto Arita
- Laboratory for Metabolomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan; Graduate School of Medical Life Science, Yokohama City University, Tsurumi-ku, Yokohama, Japan; Division of Physiological Chemistry and Metabolism, Graduate School of Pharmaceutical Sciences, Keio University, Minato-ku, Tokyo, Japan
| | - Hiroshi Kiyono
- Division of Mucosal Immunology, Department of Microbiology and Immunology and International Research and Development Center for Mucosal Vaccines, Institute of Medical Science, University of Tokyo, Tokyo, Japan; Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yasuhiro Yasutomi
- Laboratory of Immunoregulation and Vaccine Research, Tsukuba Primate Research Center, NIBIOHN, Tsukuba, Japan; Division of Immunoregulation, Department of Molecular and Experimental Medicine, Mie University Graduate School of Medicine, Tsu, Japan
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Japan
| | - Kenji Kabashima
- Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Jun Kunisawa
- Laboratory of Vaccine Materials, Center for Vaccine and Adjuvant Research, and Laboratory of Gut Environmental System, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), Ibaraki, Japan; Department of Microbiology and Immunology, Kobe University Graduate School of Medicine, Kobe, Japan; Division of Mucosal Immunology, Department of Microbiology and Immunology and International Research and Development Center for Mucosal Vaccines, Institute of Medical Science, University of Tokyo, Tokyo, Japan; Graduate School of Medicine, Graduate School of Pharmaceutical Sciences, Graduate School of Dentistry, Osaka University, Suita, Japan.
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Abstract
PURPOSE OF REVIEW This review describes the essential roles of platelets in neutrophil recruitment from the bloodstream into inflamed and infected tissues, with a focus on recent findings. RECENT FINDINGS Platelets are required for the recruitment of neutrophils to sites of inflammation and infection. They fulfil this role largely by enabling contacts of circulating neutrophils with the inflamed blood vessel wall prior to extravasation. Platelets promote both early stages of neutrophil recruitment (tethering, rolling, arrest, firm adhesion) and - as recent work has demonstrated - later stages (intravascular crawling and diapedesis). Recent studies have also begun to identify platelet-signaling pathways that can elicit the underlying interactions between platelets, neutrophils and vascular endothelial cells without stimulating concomitant platelet aggregation and thrombus formation. These pathways include Rho-guanine-nucleotide binding proteins and Rho-guanine-nucleotide exchange factors. SUMMARY Recent findings have contributed to our burgeoning understanding of the platelet-dependent mechanisms that control neutrophil recruitment to sites of inflammation and have opened up new avenues of research aimed at increasing our knowledge of these mechanisms further. These insights might lead to the development of novel anti-inflammatory drugs that will be useful in a wide range of inflammatory diseases without causing immunodeficiency.
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53
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Mascarenhas DD, Herndon DN, Arany I. Epigenetic memory of oxidative stress: does nephrilin exert its protective effects via Rac1? Biologics 2017; 11:97-106. [PMID: 28761330 PMCID: PMC5522666 DOI: 10.2147/btt.s136188] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aim Nephrilin peptide, a designed inhibitor of Rictor complex (mTORC2), exerts pleiotropic protective effects in metabolic, xenobiotic and traumatic stress models. Stress can generate enduring epigenetic changes in gene function. In this work we examine the possibility that nephrilin treatment protects against acute and enduring global changes in oxidative metabolism, with a focus on the Rictor-complex-mediated activation of Rac1, a subunit of NADPH oxidase (Nox) via PKCs, Prex1 and p66shc. Methods Given the wide range of animal models in which nephrilin peptide has previously demonstrated effectiveness in vivo, we chose three different experimental systems for this investigation: dermal fibroblasts, renal proximal tubule epithelial cells (PTECs), and kidney tissue and urine from an animal model of burn trauma in which nephrilin was previously shown to prevent loss of kidney function. Results (1) Nephrilin protects dermal fibroblasts from loss of viability and collagen synthesis after ultraviolet A (UV-A) or H2O2 insult. (2) Nephrilin reduces reactive oxygen species (ROS) formation by H2O2–treated (PTECs) with or without nicotine pretreatment. Using RNA arrays and pathway analysis we demonstrate that nicotine and H2O2-treated PTECs specifically induced Rac1 gene networks in these cells. (3) Using kidney tissue and urine from the burn trauma model we demonstrate significant elevations of [a] 8-aminoprostane in urine; [b] kidney tissue histone modification and DNA methylation; and [c] post-transcriptional phosphorylation events consistent with Rac1 activation in kidney tissue. Conclusion Nephrilin protects against oxidative stress, possibly by modulating the activation of Rac1.
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Affiliation(s)
- Desmond D Mascarenhas
- Mayflower Organization for Research & Education, Sunnyvale, CA.,Transporin, Inc., Sunnyvale, CA
| | - David N Herndon
- Department of Surgery, The University of Texas Medical Branch, and Shriners Hospitals for Children, Galveston, TX
| | - Istvan Arany
- Department of Pediatrics, Division of Pediatric Nephrology, University of Mississippi Medical Center, Jackson, MS, USA
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54
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P-Rex1 and P-Rex2 RacGEFs and cancer. Biochem Soc Trans 2017; 45:963-77. [PMID: 28710285 DOI: 10.1042/bst20160269] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/01/2017] [Accepted: 06/05/2017] [Indexed: 12/15/2022]
Abstract
Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger (P-Rex) proteins are RacGEFs that are synergistically activated by phosphatidylinositol 3,4,5-trisphosphate and Gβγ subunits of G-protein-coupled receptors. P-Rex1 and P-Rex2 share similar amino acid sequence homology, domain structure, and catalytic function. Recent evidence suggests that both P-Rex proteins may play oncogenic roles in human cancers. P-Rex1 and P-Rex2 are altered predominantly via overexpression and mutation, respectively, in various cancer types, including breast cancer, prostate cancer, and melanoma. This review compares the similarities and differences between P-Rex1 and P-Rex2 functions in human cancers in terms of cellular effects and signalling mechanisms. Emerging clinical data predict that changes in expression or mutation of P-Rex1 and P-Rex2 may lead to changes in tumour outcome, particularly in breast cancer and melanoma.
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55
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TCR-CXCR4 signaling stabilizes cytokine mRNA transcripts via a PREX1-Rac1 pathway: implications for CTCL. Blood 2017; 130:982-994. [PMID: 28694325 DOI: 10.1182/blood-2017-03-770982] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 07/05/2017] [Indexed: 02/06/2023] Open
Abstract
As with many immunopathologically driven diseases, the malignant T cells of cutaneous T-cell lymphomas (CTCLs), such as Sézary syndrome, display aberrant cytokine secretion patterns that contribute to pathology and disease progression. Targeting this disordered release of cytokines is complicated by the changing cytokine milieu that drives the phenotypic changes of CTCLs. Here, we characterize a novel signaling pathway that can be targeted to inhibit the secretion of cytokines by modulating either CXCR4 or CXCR4-mediated signaling. We demonstrate that upon ligation of the T-cell antigen receptor (TCR), the TCR associates with and transactivates CXCR4 via phosphorylation of S339-CXCR4 in order to activate a PREX1-Rac1-signaling pathway that stabilizes interleukin-2(IL-2), IL-4, and IL-10 messenger RNA (mRNA) transcripts. Pharmacologic inhibition of either TCR-CXCR4 complex formation or PREX1-Rac1 signaling in primary human T cells decreased mRNA stability and inhibited secretion of IL-2, IL-4, and IL-10. Applying this knowledge to Sézary syndrome, we demonstrate that targeting various aspects of this signaling pathway blocks both TCR-dependent and TCR-independent cytokine secretion from a Sézary syndrome-derived cell line and patient isolates. Together, these results identify multiple aspects of a novel TCR-CXCR4-signaling pathway that could be targeted to inhibit the aberrant cytokine secretion that drives the immunopathogenesis of Sézary syndrome and other immunopathological diseases.
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56
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Knafo S, Esteban JA. PTEN: Local and Global Modulation of Neuronal Function in Health and Disease. Trends Neurosci 2017; 40:83-91. [PMID: 28081942 DOI: 10.1016/j.tins.2016.11.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 11/23/2016] [Accepted: 11/29/2016] [Indexed: 11/27/2022]
Abstract
Phosphatase and tensin homolog deleted on chromosome ten (PTEN) was recently revealed to be a synaptic player during plasticity events in addition to its well-established role as a general controlling factor in cell proliferation and neuronal growth during development. Alterations of these direct actions of PTEN at synapses may lead to synaptic dysfunction with behavioral and cognitive consequences. A recent paradigmatic example of this situation, Alzheimer's disease (AD), is associated with excessive recruitment of PTEN into synapses leading to pathological synaptic depression. By contrast, some forms of autism are characterized by failure to weaken synaptic connections, which may be related to insufficient PTEN signaling. Understanding the modulation of synaptic function by PTEN in these pathologies may contribute to the development of new therapies.
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Affiliation(s)
- Shira Knafo
- Biophysics Institute, CSIC-UPV/EHU, Campus Universidad del País Vasco, Barrio Sarriena s/n, 48940 Leioa, Spain; Ikerbasque, Basque Foundation for Science, Bilbao, Basque Country, Spain.
| | - José A Esteban
- Department of Molecular Neurobiology, Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas (CSIC)/Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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Zandvakili I, Lin Y, Morris JC, Zheng Y. Rho GTPases: Anti- or pro-neoplastic targets? Oncogene 2016; 36:3213-3222. [PMID: 27991930 PMCID: PMC5464989 DOI: 10.1038/onc.2016.473] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/04/2016] [Accepted: 11/07/2016] [Indexed: 02/06/2023]
Abstract
Rho GTPases are critical signal transducers of multiple pathways. They have been proposed to be useful anti-neoplastic targets for over two decades, especially in Ras-driven cancers. Until recently, however, few in vivo studies had been carried out to test this premise. Several recent mouse model studies have verified that Rac1, RhoA, and some of their effector proteins such as PAK and ROCK, are likely anti-cancer targets for treating K-Ras-driven tumors. Other seemingly contradictory studies have suggested that at least in certain instances inhibition of individual Rho GTPases may paradoxically result in pro-neoplastic effects. Significantly, both RhoA GTPase gain- and loss-of-function mutations have been discovered in primary leukemia/lymphoma and gastric cancer by human cancer genome sequencing efforts, suggesting both pro- and anti-neoplastic roles. In this review we summarize and integrate these unexpected findings and discuss the mechanistic implications in the design and application of Rho GTPase targeting strategies in future cancer therapies.
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Affiliation(s)
- I Zandvakili
- Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Molecular and Developmental Biology Graduate Program, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Medical-Scientist Training Program, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Y Lin
- Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - J C Morris
- Division of Hematology-Oncology, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio USA
| | - Y Zheng
- Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Molecular and Developmental Biology Graduate Program, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Medical-Scientist Training Program, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
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58
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Vázquez-Prado J, Bracho-Valdés I, Cervantes-Villagrana RD, Reyes-Cruz G. Gβγ Pathways in Cell Polarity and Migration Linked to Oncogenic GPCR Signaling: Potential Relevance in Tumor Microenvironment. Mol Pharmacol 2016; 90:573-586. [DOI: 10.1124/mol.116.105338] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/14/2016] [Indexed: 12/16/2022] Open
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59
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Small GTPases and their guanine-nucleotide exchange factors and GTPase-activating proteins in neutrophil recruitment. Curr Opin Hematol 2016; 23:44-54. [PMID: 26619317 DOI: 10.1097/moh.0000000000000199] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW The review describes the roles of Rho- and Rap-guanosine triphosphatases (GTPases) and of their activators, guanine-nucleotide exchange factors (GEFs), and inhibitors, GTPase activating proteins (GAPs), in neutrophil recruitment from the blood stream into inflamed tissues, with a focus on recently identified roles in neutrophils, endothelial cells, and platelets. RECENT FINDINGS Recent studies have identified important roles of Rho- and Rap-GTPases, and of their GEFs and GAPs, in the neutrophil recruitment cascade. These proteins control the upregulation and/or activation of adhesion molecules on the surface of neutrophils, endothelial cells, and platelets, and they alter cell/cell adhesion in the vascular endothelium. This enables the capture of neutrophils from the blood stream, their migration along and through the vessel wall, and their passage into the inflamed tissue. In particular, it has recently become clear that P-Rex and Vav family Rac-GEFs in platelets are crucial for neutrophil recruitment. SUMMARY These recent findings have contributed greatly to our understanding of the signalling pathways that control neutrophil recruitment to sites of inflammation and have opened up new avenues of research in this field.
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Kazanietz MG, Barrio-Real L, Casado-Medrano V, Baker MJ, Lopez-Haber C. The P-Rex1/Rac signaling pathway as a point of convergence for HER/ErbB receptor and GPCR responses. Small GTPases 2016; 9:297-303. [PMID: 27588611 DOI: 10.1080/21541248.2016.1221273] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Guanine nucleotide Exchange Factors (GEFs) are responsible for mediating GDP/GTP exchange for specific small G proteins, such as Rac. There has been substantial evidence for the involvement of Rac-GEFs in the control of cancer cell migration and metastatic progression. We have previously established that the Rac-GEF P-Rex1 is a mediator of actin cytoskeleton rearrangements and cell motility in breast cancer cells downstream of HER/ErbB receptors and the G-Protein Coupled Receptor (GPCR) CXCR4. P-Rex1 is highly expressed in luminal A and B breast cancer compared to normal mammary tissue, whereas expression is very low in basal breast cancer, and its expression correlates with the appearance of metastasis in patients. Here, we discuss the involvement of P-Rex1 as an effector of oncogenic/metastatic receptors in breast cancer and underscore its relevance in the convergence of receptor-triggered motile signals. In addition, we provide an overview of our recent findings describing a cross-talk between HER/ErbB receptors and CXCR4, and how this impacts on the activation of P-Rex1/Rac1 signaling, as well as highlight challenges that lie ahead. We propose a model in which P-Rex1 acts as a crucial node for the integration of upstream inputs from HER/ErbB receptors and CXCR4 in luminal breast cancer cells.
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Affiliation(s)
- Marcelo G Kazanietz
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Laura Barrio-Real
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Victoria Casado-Medrano
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Martin J Baker
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Cynthia Lopez-Haber
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
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Barrows D, He JZ, Parsons R. PREX1 Protein Function Is Negatively Regulated Downstream of Receptor Tyrosine Kinase Activation by p21-activated Kinases (PAKs). J Biol Chem 2016; 291:20042-54. [PMID: 27481946 DOI: 10.1074/jbc.m116.723882] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Indexed: 12/15/2022] Open
Abstract
Downstream of receptor tyrosine kinase and G protein-coupled receptor (GPCR) stimulation, the phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchange factor (PREX) family of guanine nucleotide exchange factors (GEFs) activates Rho GTPases, leading to important roles for PREX proteins in numerous cellular processes and diseases, including cancer. PREX1 and PREX2 GEF activity is activated by the second messengers PIP3 and Gβγ, and further regulation of PREX GEF activity occurs by phosphorylation. Stimulation of receptor tyrosine kinases by neuregulin and insulin-like growth factor 1 (IGF1) leads to the phosphorylation of PREX1; however, the kinases that phosphorylate PREX1 downstream of these ligands are not known. We recently reported that the p21-activated kinases (PAKs), which are activated by GTP-bound Ras-related C3 botulinum toxin substrate 1 (Rac1), mediate the phosphorylation of PREX2 after insulin receptor activation. Here we show that certain phosphorylation events on PREX1 after insulin, neuregulin, and IGF1 treatment are PAK-dependent and lead to a reduction in PREX1 binding to PIP3 Like PREX2, PAK-mediated phosphorylation also negatively regulates PREX1 GEF activity. Furthermore, the onset of PREX1 phosphorylation was delayed compared with the phosphorylation of AKT, supporting a model of negative feedback downstream of PREX1 activation. We also found that the phosphorylation of PREX1 after isoproterenol and prostaglandin E2-mediated GPCR activation is partially PAK-dependent and likely also involves protein kinase A, which is known to reduce PREX1 function. Our data point to multiple mechanisms of PREX1 negative regulation by PAKs within receptor tyrosine kinase and GPCR-stimulated signaling pathways that have important roles in diseases such as diabetes and cancer.
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Affiliation(s)
- Douglas Barrows
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029 and the Department of Pharmacology, Columbia University, New York, New York 10032
| | - John Z He
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029 and
| | - Ramon Parsons
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029 and
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62
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Ryan MB, Finn AJ, Pedone KH, Thomas NE, Der CJ, Cox AD. ERK/MAPK Signaling Drives Overexpression of the Rac-GEF, PREX1, in BRAF- and NRAS-Mutant Melanoma. Mol Cancer Res 2016; 14:1009-1018. [PMID: 27418645 DOI: 10.1158/1541-7786.mcr-16-0184] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/01/2016] [Indexed: 12/14/2022]
Abstract
Recently, we identified that PREX1 overexpression is critical for metastatic but not tumorigenic growth in a mouse model of NRAS-driven melanoma. In addition, a PREX1 gene signature correlated with and was dependent on ERK MAPK activation in human melanoma cell lines. In the current study, the underlying mechanism of PREX1 overexpression in human melanoma was assessed. PREX1 protein levels were increased in melanoma tumor tissues and cell lines compared with benign nevi and normal melanocytes, respectively. Suppression of PREX1 by siRNA impaired invasion but not proliferation in vitro PREX1-dependent invasion was attributable to PREX1-mediated activation of the small GTPase RAC1 but not the related small GTPase CDC42. Pharmacologic inhibition of ERK signaling reduced PREX1 gene transcription and additionally regulated PREX1 protein stability. This ERK-dependent upregulation of PREX1 in melanoma, due to both increased gene transcription and protein stability, contrasts with the mechanisms identified in breast and prostate cancers, in which PREX1 overexpression was driven by gene amplification and HDAC-mediated gene transcription, respectively. Thus, although PREX1 expression is aberrantly upregulated and regulates RAC1 activity and invasion in these three different tumor types, the mechanisms of its upregulation are distinct and context dependent. IMPLICATIONS This study identifies an ERK-dependent mechanism that drives PREX1 upregulation and subsequent RAC1-dependent invasion in BRAF- and NRAS-mutant melanoma. Mol Cancer Res; 14(10); 1009-18. ©2016 AACR.
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Affiliation(s)
- Meagan B Ryan
- Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Alexander J Finn
- Department of Dermatology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Katherine H Pedone
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Nancy E Thomas
- Department of Dermatology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Channing J Der
- Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
| | - Adrienne D Cox
- Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
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Heregulin/ErbB3 Signaling Enhances CXCR4-Driven Rac1 Activation and Breast Cancer Cell Motility via Hypoxia-Inducible Factor 1α. Mol Cell Biol 2016; 36:2011-26. [PMID: 27185877 DOI: 10.1128/mcb.00180-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/06/2016] [Indexed: 01/11/2023] Open
Abstract
The growth factor heregulin (HRG), a ligand of ErbB3 and ErbB4 receptors, contributes to breast cancer development and the promotion of metastatic disease, and its expression in breast tumors has been associated with poor clinical outcome and resistance to therapy. In this study, we found that breast cancer cells exposed to sustained HRG treatment show markedly enhanced Rac1 activation and migratory activity in response to the CXCR4 ligand SDF-1/CXCL12, effects mediated by P-Rex1, a Rac-guanine nucleotide exchange factor (GEF) aberrantly expressed in breast cancer. Notably, HRG treatment upregulates surface expression levels of CXCR4, a G protein-coupled receptor (GPCR) implicated in breast cancer metastasis and an indicator of poor prognosis in breast cancer patients. A detailed mechanistic analysis revealed that CXCR4 upregulation and sensitization of the Rac response/motility by HRG are mediated by the transcription factor hypoxia-inducible factor 1α (HIF-1α) via ErbB3 and independently of ErbB4. HRG caused prominent induction in the nuclear expression of HIF-1α, which transcriptionally activates the CXCR4 gene via binding to a responsive element located in positions -1376 to -1372 in the CXCR4 promoter, as revealed by mutagenesis analysis and chromatin immunoprecipitation (ChIP). Our results uncovered a novel function for ErbB3 in enhancing breast cancer cell motility and sensitization of the P-Rex1/Rac1 pathway through HIF-1α-mediated transcriptional induction of CXCR4.
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Identification of P-Rex1 as an anti-inflammatory and anti-fibrogenic target for pulmonary fibrosis. Sci Rep 2016; 6:25785. [PMID: 27173636 PMCID: PMC4865757 DOI: 10.1038/srep25785] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/13/2016] [Indexed: 12/15/2022] Open
Abstract
Pulmonary fibrosis (PF) leads to progressive and often irreversible loss of lung functions, posing a health threat with no effective cure. We examined P-Rex1, a PI3K- and G protein βγ-regulated guanine nucleotide exchange factor (GEF) of the Rac small GTPase, for its potential involvement in PF. In a bleomycin-induced PF model, mice deficient in p-rex1 had well-preserved alveolar structure and survived significantly better than their wild type (WT) littermates. The p-rex1−/− mice expressed significantly less proinflammatory cytokines and chemokines and had reduced leukocyte infiltration in the lung tissue than their WT littermates. P-Rex1 was detected in lung fibroblasts of WT mice, and its genetic deletion attenuated TGFβ-1-stimulated lung fibroblast migration, Rac1 activation and p38 MAPK phosphorylation. The p-rex1−/− mice showed significantly reduced pathological changes including the expression of α-smooth muscle actin, fibronectin and TGFβ-1 compared with their WT controls. Expression of a GEF-deficient P-Rex1 mutant effectively blocked Smads-dependent transcriptional activation, suggesting that P-Rex1 is a downstream mediator of TGFβ-1 signaling. These findings identify P-Rex1 as a novel player of PF, suggesting that targeting P-Rex1 may simultaneously block the inflammatory and fibrogenic processes of PF.
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Hotulainen P, Saarikangas J. The initiation of post-synaptic protrusions. Commun Integr Biol 2016; 9:e1125053. [PMID: 27489575 PMCID: PMC4951170 DOI: 10.1080/19420889.2015.1125053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 11/20/2015] [Accepted: 11/20/2015] [Indexed: 02/02/2023] Open
Abstract
The post-synaptic spines of neuronal dendrites are highly elaborate membrane protrusions. Their anatomy, stability and density are intimately linked to cognitive performance. The morphological transitions of spines are powered by coordinated polymerization of actin filaments against the plasma membrane, but how the membrane-associated polymerization is spatially and temporally regulated has remained ill defined. Here, we discuss our recent findings showing that dendritic spines can be initiated by direct membrane bending by the I-BAR protein MIM/Mtss1. This lipid phosphatidylinositol (PI(4,5)P2) signaling-activated membrane bending coordinated spatial actin assembly and promoted spine formation. From recent advances, we formulate a general model to discuss how spatially concentrated protein-lipid microdomains formed by multivalent interactions between lipids and actin/membrane regulatory proteins might launch cell protrusions.
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Affiliation(s)
- Pirta Hotulainen
- Neuroscience Center, University of Helsinki, Helsinki, Finland; Minerva Foundation Institute for Medical Research, Helsinki, Finland
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Chávez-Vargas L, Adame-García SR, Cervantes-Villagrana RD, Castillo-Kauil A, Bruystens JGH, Fukuhara S, Taylor SS, Mochizuki N, Reyes-Cruz G, Vázquez-Prado J. Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor: EFFECT ON PKA LOCALIZATION AND P-Rex1 SIGNALING. J Biol Chem 2016; 291:6182-99. [PMID: 26797121 DOI: 10.1074/jbc.m115.712216] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 12/15/2022] Open
Abstract
Morphology of migrating cells is regulated by Rho GTPases and fine-tuned by protein interactions and phosphorylation. PKA affects cell migration potentially through spatiotemporal interactions with regulators of Rho GTPases. Here we show that the endogenous regulatory (R) subunit of type I PKA interacts with P-Rex1, a Rac guanine nucleotide exchange factor that integrates chemotactic signals. Type I PKA holoenzyme interacts with P-Rex1 PDZ domains via the CNB B domain of RIα, which when expressed by itself facilitates endothelial cell migration. P-Rex1 activation localizes PKA to the cell periphery, whereas stimulation of PKA phosphorylates P-Rex1 and prevents its activation in cells responding to SDF-1 (stromal cell-derived factor 1). The P-Rex1 DEP1 domain is phosphorylated at Ser-436, which inhibits the DH-PH catalytic cassette by direct interaction. In addition, the P-Rex1 C terminus is indirectly targeted by PKA, promoting inhibitory interactions independently of the DEP1-PDZ2 region. A P-Rex1 S436A mutant construct shows increased RacGEF activity and prevents the inhibitory effect of forskolin on sphingosine 1-phosphate-dependent endothelial cell migration. Altogether, these results support the idea that P-Rex1 contributes to the spatiotemporal localization of type I PKA, which tightly regulates this guanine exchange factor by a multistep mechanism, initiated by interaction with the PDZ domains of P-Rex1 followed by direct phosphorylation at the first DEP domain and putatively indirect regulation of the C terminus, thus promoting inhibitory intramolecular interactions. This reciprocal regulation between PKA and P-Rex1 might represent a key node of integration by which chemotactic signaling is fine-tuned by PKA.
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Affiliation(s)
| | - Sendi Rafael Adame-García
- Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico
| | | | - Alejandro Castillo-Kauil
- Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico
| | | | - Shigetomo Fukuhara
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute (NCVC), Osaka, 565-8565 Japan, and
| | - Susan S Taylor
- Departments of Chemistry and Biochemistry and Pharmacology, University of California San Diego, La Jolla, California 92093
| | - Naoki Mochizuki
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute (NCVC), Osaka, 565-8565 Japan, and
| | - Guadalupe Reyes-Cruz
- Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico
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Pan D, Barber MA, Hornigold K, Baker MJ, Toth JM, Oxley D, Welch HCE. Norbin Stimulates the Catalytic Activity and Plasma Membrane Localization of the Guanine-Nucleotide Exchange Factor P-Rex1. J Biol Chem 2016; 291:6359-75. [PMID: 26792863 PMCID: PMC4813545 DOI: 10.1074/jbc.m115.686592] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Indexed: 12/15/2022] Open
Abstract
P-Rex1 is a guanine-nucleotide exchange factor (GEF) that activates the small G protein (GTPase) Rac1 to control Rac1-dependent cytoskeletal dynamics, and thus cell morphology. Three mechanisms of P-Rex1 regulation are currently known: (i) binding of the phosphoinositide second messenger PIP3, (ii) binding of the Gβγ subunits of heterotrimeric G proteins, and (iii) phosphorylation of various serine residues. Using recombinant P-Rex1 protein to search for new binding partners, we isolated the G-protein-coupled receptor (GPCR)-adaptor protein Norbin (Neurochondrin, NCDN) from mouse brain fractions. Coimmunoprecipitation confirmed the interaction between overexpressed P-Rex1 and Norbin in COS-7 cells, as well as between endogenous P-Rex1 and Norbin in HEK-293 cells. Binding assays with purified recombinant proteins showed that their interaction is direct, and mutational analysis revealed that the pleckstrin homology domain of P-Rex1 is required. Rac-GEF activity assays with purified recombinant proteins showed that direct interaction with Norbin increases the basal, PIP3- and Gβγ-stimulated Rac-GEF activity of P-Rex1. Pak-CRIB pulldown assays demonstrated that Norbin promotes the P-Rex1-mediated activation of endogenous Rac1 upon stimulation of HEK-293 cells with lysophosphatidic acid. Finally, immunofluorescence microscopy and subcellular fractionation showed that coexpression of P-Rex1 and Norbin induces a robust translocation of both proteins from the cytosol to the plasma membrane, as well as promoting cell spreading, lamellipodia formation, and membrane ruffling, cell morphologies generated by active Rac1. In summary, we have identified a novel mechanism of P-Rex1 regulation through the GPCR-adaptor protein Norbin, a direct P-Rex1 interacting protein that promotes the Rac-GEF activity and membrane localization of P-Rex1.
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Affiliation(s)
| | | | | | | | | | - David Oxley
- the Mass Spectrometry Facility, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
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Affiliation(s)
| | - Nicolas Bourmeyster
- Laboratoire Signalisation et Transports Ioniques Membranaires (STIM); Université de Poitiers Poitiers Cédex, France
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