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Tojjari A, Saeed A, Sadeghipour A, Kurzrock R, Cavalcante L. Overcoming Immune Checkpoint Therapy Resistance with SHP2 Inhibition in Cancer and Immune Cells: A Review of the Literature and Novel Combinatorial Approaches. Cancers (Basel) 2023; 15:5384. [PMID: 38001644 PMCID: PMC10670368 DOI: 10.3390/cancers15225384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 10/13/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
SHP2 (Src Homology 2 Domain-Containing Phosphatase 2) is a protein tyrosine phosphatase widely expressed in various cell types. SHP2 plays a crucial role in different cellular processes, such as cell proliferation, differentiation, and survival. Aberrant activation of SHP2 has been implicated in multiple human cancers and is considered a promising therapeutic target for treating these malignancies. The PTPN11 gene and functions encode SHP2 as a critical signal transduction regulator that interacts with key signaling molecules in both the RAS/ERK and PD-1/PD-L1 pathways; SHP2 is also implicated in T-cell signaling. SHP2 may be inhibited by molecules that cause allosteric (bind to sites other than the active site and attenuate activation) or orthosteric (bind to the active site and stop activation) inhibition or via potent SHP2 degraders. These inhibitors have anti-proliferative effects in cancer cells and suppress tumor growth in preclinical models. In addition, several SHP2 inhibitors are currently in clinical trials for cancer treatment. This review aims to provide an overview of the current research on SHP2 inhibitors, including their mechanism of action, structure-activity relationships, and clinical development, focusing on immune modulation effects and novel therapeutic strategies in the immune-oncology field.
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Affiliation(s)
- Alireza Tojjari
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15232, USA
| | - Anwaar Saeed
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15232, USA
| | - Arezoo Sadeghipour
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modarres University, Tehran P.O. Box 14115-175, Iran
| | - Razelle Kurzrock
- Department of Medicine, Genome Sciences and Precision Medicine Center, Medical College of Wisconsin Cancer Center, Milwaukee, WI 53226, USA
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Beyond the Cell Surface: Targeting Intracellular Negative Regulators to Enhance T cell Anti-Tumor Activity. Int J Mol Sci 2019; 20:ijms20235821. [PMID: 31756921 PMCID: PMC6929154 DOI: 10.3390/ijms20235821] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 02/07/2023] Open
Abstract
It is well established that extracellular proteins that negatively regulate T cell function, such as Cytotoxic T-Lymphocyte-Associated protein 4 (CTLA-4) and Programmed Cell Death protein 1 (PD-1), can be effectively targeted to enhance cancer immunotherapies and Chimeric Antigen Receptor T cells (CAR-T cells). Intracellular proteins that inhibit T cell receptor (TCR) signal transduction, though less well studied, are also potentially useful therapeutic targets to enhance T cell activity against tumor. Four major classes of enzymes that attenuate TCR signaling include E3 ubiquitin kinases such as the Casitas B-lineage lymphoma proteins (Cbl-b and c-Cbl), and Itchy (Itch), inhibitory tyrosine phosphatases, such as Src homology region 2 domain-containing phosphatases (SHP-1 and SHP-2), inhibitory protein kinases, such as C-terminal Src kinase (Csk), and inhibitory lipid kinases such as Src homology 2 (SH2) domain-containing inositol polyphosphate 5-phosphatase (SHIP) and Diacylglycerol kinases (DGKs). This review describes the mechanism of action of eighteen intracellular inhibitory regulatory proteins in T cells within these four classes, and assesses their potential value as clinical targets to enhance the anti-tumor activity of endogenous T cells and CAR-T cells.
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Maruca A, Ambrosio FA, Lupia A, Romeo I, Rocca R, Moraca F, Talarico C, Bagetta D, Catalano R, Costa G, Artese A, Alcaro S. Computer-based techniques for lead identification and optimization I: Basics. PHYSICAL SCIENCES REVIEWS 2019. [DOI: 10.1515/psr-2018-0113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThis chapter focuses on computational techniques for identifying and optimizing lead molecules, with a special emphasis on natural compounds. A number of case studies have been specifically discussed, such as the case of the naphthyridine scaffold, discovered through a structure-based virtual screening (SBVS) and proposed as the starting point for further lead optimization process, to enhance its telomeric RNA selectivity. Another example is the case of Liphagal, a tetracyclic meroterpenoid extracted fromAka coralliphaga, known as PI3Kα inhibitor, provide an evidence for the design of new active congeners against PI3Kα using molecular dynamics (MD) simulations. These are only two of the numerous examples of the computational techniques’ powerful in drug design and drug discovery fields. Finally, the design of drugs that can simultaneously interact with multiple targets as a promising approach for treating complicated diseases has been reported. An example of polypharmacological agents are the compounds extracted from mushrooms identified by means of molecular docking experiments. This chapter may be a useful manual of molecular modeling techniques used in the lead-optimization and lead identification processes.
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Luo CT, Li MO. Foxo transcription factors in T cell biology and tumor immunity. Semin Cancer Biol 2018; 50:13-20. [PMID: 29684436 DOI: 10.1016/j.semcancer.2018.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 04/13/2018] [Accepted: 04/17/2018] [Indexed: 01/05/2023]
Abstract
The evolutionally conserved forkhead box O (Foxo) family of transcription factors is pivotal in the control of nutrient sensing and stress responses. Recent studies have revealed that the Foxo proteins have been rewired to regulate highly specialized T cell activities. Here, we review the latest advances in the understanding of how Foxo transcription factors control T cell biology, including T cell trafficking, naive T cell homeostasis, effector and memory responses, as well as the differentiation and function of regulatory T cells. We also discuss the emerging evidence on Foxo-mediated regulation in antitumor immunity. Future work will further explore how the Foxo-dependent programs in T cells can be exploited for cancer immunotherapy.
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Affiliation(s)
- Chong T Luo
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ming O Li
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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The potential role of in silico approaches to identify novel bioactive molecules from natural resources. Future Med Chem 2017; 9:1665-1686. [PMID: 28841048 DOI: 10.4155/fmc-2017-0124] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In recent years, integration of in silico approaches to natural product (NP) research reawakened the declined interest in NP-based drug discovery efforts. In particular, advancements in cheminformatics enabled comparison of NP databases with contemporary small-molecule libraries in terms of molecular properties and chemical space localizations. Virtual screening and target fishing approaches were successful in recognizing the untold macromolecular targets for NPs to exploit the unmet therapeutic needs. Developments in molecular docking and scoring methods along with molecular dynamics enabled to predict the target-ligand interactions more accurately taking into consideration the remarkable structural complexity of NPs. Hence, innovative in silico strategies have contributed valuably to the NP research in drug discovery processes as reviewed herein. [Formula: see text].
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Li F, Li L, Cheng M, Wang X, Hao J, Liu S, Duan H. SHIP, a novel factor to ameliorate extracellular matrix accumulation via suppressing PI3K/Akt/CTGF signaling in diabetic kidney disease. Biochem Biophys Res Commun 2016; 482:1477-1483. [PMID: 27965087 DOI: 10.1016/j.bbrc.2016.12.060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 12/08/2016] [Indexed: 01/05/2023]
Abstract
Tubular interstitial extracellular matrix accumulation, which plays a key role in the pathogenesis and progression of diabetic kidney disease (DKD), is believed to be mediated by activation of PI3K/Akt signal pathway. However, it is still not clear whether SH2 domain-containing inositol 5'-phosphatase (SHIP), known as a negative regulator of PI3K/Akt pathway is also involved in extracellular matrix metabolism of diabetic kidney. In the present study, decreased SHIP and increased phospho-Akt (Ser 473, Thr 308) were found in renal tubular cells of diabetic mice accompanied by overexpression of connective tissue growth factor (CTGF) and extracellular matrix deposition versus normal mice. Again, high glucose attenuated SHIP expression in a time-dependent manner, concomitant with activation of PI3K/Akt signaling and extracellular matrix production in human renal proximal tubular epithelial cells (HK2) cultured in vitro, which was significantly prevented by transfection of M90-SHIP vector. Furthermore, in vivo delivery of rAd-INPP5D vector (SHIP expression vector) via intraperitoneal injection in diabetic mice increased SHIP expression by 3.36 times followed by 65.26%, 70.38% and 46.71% decreases of phospho-Akt (Ser 473), phospho-Akt (Thr 308) and CTGF expression versus diabetic mice receiving rAd-EGFP vector. Meanwhile, increased renal extracellular matrix accumulation of diabetic mice was also inhibited with intraperitoneal injection of rAd-INPP5D vector. These above data suggested that overexpression of SHIP might be a potent method to lessen renal extracellular matrix accumulation via inactivation of PI3K/Akt pathway and suppression of CTGF expression in DKD.
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Affiliation(s)
- Fan Li
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Lisha Li
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Meijuan Cheng
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Xiumin Wang
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Jun Hao
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Shuxia Liu
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Huijun Duan
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China.
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Marijuana-derived Δ-9-tetrahydrocannabinol suppresses Th1/Th17 cell-mediated delayed-type hypersensitivity through microRNA regulation. J Mol Med (Berl) 2016; 94:1039-51. [PMID: 27038180 DOI: 10.1007/s00109-016-1404-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/10/2016] [Accepted: 03/07/2016] [Indexed: 10/22/2022]
Abstract
UNLABELLED ∆(9)-Tetrahydrocannabinol (THC) is one of the major bioactive cannabinoids derived from the Cannabis sativa plant and is known for its anti-inflammatory properties. Delayed-type hypersensitivity (DTH) is driven by proinflammatory T helper cells including the classic inflammatory Th1 lineage as well as the more recently discovered Th17 lineage. In the current study, we investigated whether THC can alter the induction of Th1/Th17 cells involved in mBSA-induced DTH response. THC treatment (20 mg/kg) of C57BL/6 mice with DTH caused decreased swelling and infiltration of immune cells at the site of antigen rechallenge. Additionally, THC treatment decreased lymphocyte activation as well as Th1/Th17 lineage commitment, including reduced lineage-specific transcription factors and cytokines. Interestingly, while DTH caused an overexpression of miR-21, which increases Th17 differentiation via SMAD7 inhibition, and downregulation of miR-29b, an IFN-γ inhibitor, THC treatment reversed this microRNA (miR) dysregulation. Furthermore, when we transfected primary cells from DTH mice with miR-21 inhibitor or miR-29b mimic, as seen with THC treatment, the expression of target gene message was directly impacted increasing SMAD7 and decreasing IFN-γ expression, respectively. In summary, the current study suggests that THC treatment during DTH response can simultaneously inhibit Th1/Th17 activation via regulation of microRNA (miRNA) expression. KEY MESSAGES • THC treatment inhibits simultaneous Th1/Th17 driven inflammation. • THC treatment corrects DTH-mediated microRNA dysregulation. • THC treatment regulates proinflammatory cytokines and transcription factors.
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Lupia E, Pigozzi L, Goffi A, Hirsch E, Montrucchio G. Role of phosphoinositide 3-kinase in the pathogenesis of acute pancreatitis. World J Gastroenterol 2014; 20:15190-15199. [PMID: 25386068 PMCID: PMC4223253 DOI: 10.3748/wjg.v20.i41.15190] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 06/12/2014] [Accepted: 07/22/2014] [Indexed: 02/06/2023] Open
Abstract
A large body of experimental and clinical data supports the notion that inflammation in acute pancreatitis has a crucial role in the pathogenesis of local and systemic damage and is a major determinant of clinical severity. Thus, research has recently focused on molecules that can regulate the inflammatory processes, such as phosphoinositide 3-kinases (PI3Ks), a family of lipid and protein kinases involved in intracellular signal transduction. Studies using genetic ablation or pharmacologic inhibitors of different PI3K isoforms, in particular the class I PI3Kδ and PI3Kγ, have contributed to a greater understanding of the roles of these kinases in the modulation of inflammatory and immune responses. Recent data suggest that PI3Ks are also involved in the pathogenesis of acute pancreatitis. Activation of the PI3K signaling pathway, and in particular of the class IB PI3Kγ isoform, has a significant role in those events which are necessary for the initiation of acute pancreatic injury, namely calcium signaling alteration, trypsinogen activation, and nuclear factor-κB transcription. Moreover, PI3Kγ is instrumental in modulating acinar cell apoptosis, and regulating local neutrophil infiltration and systemic inflammatory responses during the course of experimental acute pancreatitis. The availability of PI3K inhibitors selective for specific isoforms may provide new valuable therapeutic strategies to improve the clinical course of this disease. This article presents a brief summary of PI3K structure and function, and highlights recent advances that implicate PI3Ks in the pathogenesis of acute pancreatitis.
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Biethahn K, Orinska Z, Vigorito E, Goyeneche-Patino DA, Mirghomizadeh F, Föger N, Bulfone-Paus S. miRNA-155 controls mast cell activation by regulating the PI3Kγ pathway and anaphylaxis in a mouse model. Allergy 2014; 69:752-62. [PMID: 24734904 DOI: 10.1111/all.12407] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Mast cells (MCs) play a central role in allergic and inflammatory disorders by rapid degranulation and release of inflammatory mediators upon antigen-driven engagement of the FcεRI. Receptor-mediated MC responses are controlled by the activation of different isoforms of phosphoinositide-3-kinase (PI3K) and the downstream signaling processes. Recent evidence suggests that miRNAs are important molecular players regulating the PI3K/Akt pathway. METHODS The role of miR-155 in the regulation of MC functions in vivo was studied in the passive cutaneous anaphylaxis (PCA) MC-dependent model. WT and miR-155(-/-) mice were injected intradermally with anti-DNP-IgE and intravenously with the antigen DNP-HSA. Ear swelling was assessed to evaluate the anaphylactic response. All investigations, to characterize miR-155 specific activities in MCs, were conducted comparing WT and miR-155(-/-) bone marrow-derived MCs (BMMCs). RESULTS We report that miR-155(-/-) mice display enhanced anaphylaxis reactions. Although miR-155(-/-) BMMCs show normal development, proliferation, and survival, miR-155 deficiency enhances FcεRI-mediated degranulation and release of TNF-α, IL-13, and IL-6. Interestingly, the level of Akt phosphorylation on both of its regulatory residues Thr308 and Ser473 was increased in miR-155(-/-) compared to WT BMMCs. Gene expression profiling showed that miR-155(-/-) BMMCs exhibited significantly increased expression of the adapter PI3Kγ subunits Pik3r5 (p101) and Pik3r6 (p84, p87(PIKAP) ). Furthermore, selective blockade of the PI3Kγ pathway inhibited degranulation in miR-155(-/-) BMMCs. CONCLUSIONS Thus, we suggest that miR-155 plays a critical role in FcεRI-mediated MC responses by modulating components of the PI3Kγ pathway. This newly identified mechanism of miRNA-controlled MC activation may affect the initiation and maintenance of allergic disorders.
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Affiliation(s)
| | - Z. Orinska
- Research Center Borstel; Borstel Germany
| | | | | | | | - N. Föger
- Research Center Borstel; Borstel Germany
- Institute for Clinical Chemistry; Hannover Medical School; Hannover Germany
| | - S. Bulfone-Paus
- Research Center Borstel; Borstel Germany
- Faculty of Human and Medical Sciences; Institute for Inflammation and Repair and MCCIR; University of Manchester; Manchester UK
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Huang YY, Xia MZ, Wang H, Liu XJ, Hu YF, Chen YH, Zhang C, Xu DX. Cadmium selectively induces MIP-2 and COX-2 through PTEN-mediated Akt activation in RAW264.7 cells. Toxicol Sci 2014; 138:310-21. [PMID: 24449419 DOI: 10.1093/toxsci/kfu013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Increasing evidence demonstrates that cadmium (Cd) induces inflammation, but its mechanisms remain obscure. The present study showed that treatment with CdCl₂ selectively upregulates macrophage inflammatory protein (MIP)-2 and cyclooxygenase (COX)-2 in RAW264.7 cells. Concomitantly, Cd²⁺ markedly elevated the level of phosphorylated Akt in dose- and time-dependent manners. LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), blocked Cd²⁺-evoked Akt phosphorylation. Correspondingly, LY294002 significantly repressed Cd²⁺-induced upregulation of MIP-2 and COX-2 in RAW264.7 cells. Further experiments showed that treatment with Cd²⁺ significantly reduced the level of PTEN protein in RAW264.7 cells. MG132, a specific proteasome inhibitor, blocked Cd²⁺-induced reduction in PTEN protein as well as Akt phosphorylation, implicating the involvement of proteasome-mediated PTEN degradation. Of interest, Cd²⁺-induced degradation of PTEN protein appears to be associated with PTEN ubiquitination. N-acetylcysteine, a glutathione (GSH) precursor, blocked Cd²⁺-evoked PTEN degradation as well as Akt phosphorylation. By contrast, L-buthionine-S,R-sulfoximine, an inhibitor of cellular GSH synthesis, exacerbated Cd²⁺-induced PTEN degradation and Akt phosphorylation. Alpha-phenyl-N-tert-butylnitrone and vitamin C, two antioxidants, did not prevent from Cd²⁺-induced PTEN degradation and Akt phosphorylation. In conclusion, Cd²⁺ selectively induces MIP-2 and COX-2 through PTEN-mediated PI3K/Akt activation. Cellular GSH depletion mediates Cd²⁺-induced PTEN degradation and subsequent PI3K/Akt activation in macrophages.
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Affiliation(s)
- Yin-Yin Huang
- Department of Toxicology, Anhui Medical University, Hefei, China
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Victorino F, Alper S. Identifying novel spatiotemporal regulators of innate immunity. Immunol Res 2013; 55:3-9. [PMID: 22926826 DOI: 10.1007/s12026-012-8344-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The innate immune response plays a critical role in pathogen clearance. However, dysregulation of innate immunity contributes to acute inflammatory diseases such as sepsis and many chronic inflammatory diseases including asthma, arthritis, and Crohn's disease. Pathogen recognition receptors including the Toll-like family of receptors play a pivotal role in the initiation of inflammation and in the pathogenesis of many diseases with an inflammatory component. Studies over the last 15 years have identified complex innate immune signal transduction pathways involved in inflammation that have provided many new potential therapeutic targets to treat disease. We are investigating several novel genes that exert spatial and in some cases temporal regulation on innate immunity signaling pathways. These novel genes include Tbc1d23, a RAB-GAP that inhibits innate immunity. In this review, we will discuss inflammation, the role of inflammation in disease, innate immune signal transduction pathways, and the use of spatiotemporal regulators of innate immunity as potential targets for discovery and therapeutics.
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Affiliation(s)
- Francisco Victorino
- Integrated Department of Immunology, National Jewish Health and the University of Colorado School of Medicine, Denver, CO 80206, USA
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Collazo MM, Paraiso KHT, Park MY, Hazen AL, Kerr WG. Lineage extrinsic and intrinsic control of immunoregulatory cell numbers by SHIP. Eur J Immunol 2012; 42:1785-95. [PMID: 22535653 DOI: 10.1002/eji.201142092] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We previously showed that germline or induced SHIP deficiency expands immuno-regulatory cell numbers in T lymphoid and myeloid lineages. We postulated these increases could be interrelated. Here, we show that myeloid-specific ablation of SHIP leads to the expansion of both myeloid-derived suppressor cell (MDSC) and regulatory T (Treg) cell numbers, indicating SHIP-dependent control of Treg-cell numbers by a myeloid cell type. Conversely, T-lineage specific ablation of SHIP leads to expansion of Treg-cell numbers, but not expansion of the MDSC compartment, indicating SHIP also has a lineage intrinsic role in limiting Treg-cell numbers. However, the SHIP-deficient myeloid cell that promotes MDSC and Treg-cell expansion is not an MDSC as they lack SHIP protein expression. Thus, regulation of MDSC numbers in vivo must be controlled in a cell-extrinsic fashion by another myeloid cell type. We had previously shown that G-CSF levels are profoundly increased in SHIP(-/-) mice, suggesting this myelopoietic growth factor could promote MDSC expansion in a cell-extrinsic fashion. Consistent with this hypothesis, we find that G-CSF is required for expansion of the MDSC splenic compartment in mice rendered SHIP-deficient as adults. Thus, SHIP controls MDSC numbers, in part, by limiting production of the myelopoietic growth factor G-CSF.
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Affiliation(s)
- Michelle M Collazo
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL, USA
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Foster JG, Blunt MD, Carter E, Ward SG. Inhibition of PI3K signaling spurs new therapeutic opportunities in inflammatory/autoimmune diseases and hematological malignancies. Pharmacol Rev 2012; 64:1027-54. [PMID: 23023033 DOI: 10.1124/pr.110.004051] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The phosphoinositide 3-kinase/mammalian target of rapamycin/protein kinase B (PI3K/mTOR/Akt) signaling pathway is central to a plethora of cellular mechanisms in a wide variety of cells including leukocytes. Perturbation of this signaling cascade is implicated in inflammatory and autoimmune disorders as well as hematological malignancies. Proteins within the PI3K/mTOR/Akt pathway therefore represent attractive targets for therapeutic intervention. There has been a remarkable evolution of PI3K inhibitors in the past 20 years from the early chemical tool compounds to drugs that are showing promise as anticancer agents in clinical trials. The use of animal models and pharmacological tools has expanded our knowledge about the contribution of individual class I PI3K isoforms to immune cell function. In addition, class II and III PI3K isoforms are emerging as nonredundant regulators of immune cell signaling revealing potentially novel targets for disease treatment. Further complexity is added to the PI3K/mTOR/Akt pathway by a number of novel signaling inputs and feedback mechanisms. These can present either caveats or opportunities for novel drug targets. Here, we consider recent advances in 1) our understanding of the contribution of individual PI3K isoforms to immune cell function and their relevance to inflammatory/autoimmune diseases as well as lymphoma and 2) development of small molecules with which to inhibit the PI3K pathway. We also consider whether manipulating other proximal elements of the PI3K signaling cascade (such as class II and III PI3Ks or lipid phosphatases) are likely to be successful in fighting off different immune diseases.
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Affiliation(s)
- John G Foster
- Inflammatory Cell Biology Laboratory, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, UK.
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Han JM, Patterson SJ, Levings MK. The Role of the PI3K Signaling Pathway in CD4(+) T Cell Differentiation and Function. Front Immunol 2012; 3:245. [PMID: 22905034 PMCID: PMC3417165 DOI: 10.3389/fimmu.2012.00245] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 07/23/2012] [Indexed: 12/15/2022] Open
Abstract
The relative activity of regulatory versus conventional CD4(+) T cells ultimately maintains the delicate balance between immune tolerance and inflammation. At the molecular level, the activity of phosphatidylinositol 3-kinase (PI3K) and its downstream positive and negative regulators has a major role in controlling the balance between immune regulation and activation of different subsets of effector CD4(+) T cells. In contrast to effector T cells which require activation of the PI3K to differentiate and mediate their effector function, regulatory T cells rely on minimal activation of this pathway to develop and maintain their characteristic phenotype, function, and metabolic state. In this review, we discuss the role of the PI3K signaling pathway in CD4(+) T cell differentiation and function, and focus on how modulation of this pathway in T cells can alter the outcome of an immune response, ultimately tipping the balance between tolerance and inflammation.
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Affiliation(s)
- Jonathan M Han
- Department of Surgery, Child and Family Research Institute, The University of British Columbia Vancouver, BC, Canada
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15
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Meimetis LG, Nodwell M, Yang L, Wang X, Wu J, Harwig C, Stenton GR, Mackenzie LF, MacRury T, Patrick BO, Ming-Lum A, Ong CJ, Krystal G, Mui ALF, Andersen RJ. Synthesis of SHIP1-Activating Analogs of the Sponge Meroterpenoid Pelorol. European J Org Chem 2012. [DOI: 10.1002/ejoc.201200631] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Blunt MD, Ward SG. Pharmacological targeting of phosphoinositide lipid kinases and phosphatases in the immune system: success, disappointment, and new opportunities. Front Immunol 2012; 3:226. [PMID: 22876243 PMCID: PMC3410520 DOI: 10.3389/fimmu.2012.00226] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 07/12/2012] [Indexed: 12/24/2022] Open
Abstract
The predominant expression of the γ and δ isoforms of PI3K in cells of hematopoietic lineage prompted speculation that inhibitors of these isoforms could offer opportunities for selective targeting of PI3K in the immune system in a range of immune-related pathologies. While there has been some success in developing PI3Kδ inhibitors, progress in developing selective inhibitors of PI3Kγ has been rather disappointing. This has prompted the search for alternative targets with which to modulate PI3K signaling specifically in the immune system. One such target is the SH2 domain-containing inositol-5-phosphatase-1 (SHIP-1) which de-phosphorylates PI(3,4,5)P3 at the D5 position of the inositol ring to create PI(3,4)P2. In this article, we first describe the current state of PI3K isoform-selective inhibitor development. We then focus on the structure of SHIP-1 and its function in the immune system. Finally, we consider the current state of development of small molecule compounds that potently and selectively modulate SHIP activity and which offer novel opportunities to manipulate PI3K mediated signaling in the immune system.
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Affiliation(s)
- Matthew D Blunt
- Inflammatory Cell Biology Laboratory, Department of Pharmacy and Pharmacology, University of Bath Bath, UK
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Carnevale D, Lembo G. PI3K in hypertension: a novel therapeutic target controlling vascular myogenic tone and target organ damage. Cardiovasc Res 2012; 95:403-8. [DOI: 10.1093/cvr/cvs166] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Blunt MD, Ward SG. Targeting PI3K isoforms and SHIP in the immune system: new therapeutics for inflammation and leukemia. Curr Opin Pharmacol 2012; 12:444-51. [PMID: 22483603 DOI: 10.1016/j.coph.2012.02.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 02/23/2012] [Indexed: 10/28/2022]
Abstract
PI3K is critical for the normal function of the immune system, however dysregulated PI3K mediated signaling has been linked to the development of many immune mediated pathologies. This review describes current progress in the development of isoform-specific PI3K inhibitors that hold promise for the treatment of hematopoietic malignancies as well as for inflammatory and autoimmune diseases. A SH2-domain containing inositol-5-phosphatase (SHIP) is a regulator of PI3K signaling, and is also discussed as a potential drug target for immunomodulation and the treatment of leukemia. Recent progress has been made in the development of small molecule compounds that potently and selectively modulate SHIP activity and hence provide a novel mechanism to alter PI3K mediated signaling.
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Affiliation(s)
- Matthew D Blunt
- Inflammatory Cell Biology Laboratory, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK
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Kang BN, Ha SG, Ge XN, Reza Hosseinkhani M, Bahaie NS, Greenberg Y, Blumenthal MN, Puri KD, Rao SP, Sriramarao P. The p110δ subunit of PI3K regulates bone marrow-derived eosinophil trafficking and airway eosinophilia in allergen-challenged mice. Am J Physiol Lung Cell Mol Physiol 2012; 302:L1179-91. [PMID: 22427531 DOI: 10.1152/ajplung.00005.2012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Trafficking and recruitment of eosinophils during allergic airway inflammation is mediated by the phosphatidylinositol 3-kinase (PI3K) family of signaling molecules. The role played by the p110δ subunit of PI3K (PI3K p110δ) in regulating eosinophil trafficking and recruitment was investigated using a selective pharmacological inhibitor (IC87114). Treatment with the PI3K p110δ inhibitor significantly reduced murine bone marrow-derived eosinophil (BM-Eos) adhesion to VCAM-1 as well as ICAM-1 and inhibited activation-induced changes in cell morphology associated with reduced Mac-1 expression and aberrant cell surface localization/distribution of Mac-1 and α4. Infused BM-Eos demonstrated significantly decreased rolling and adhesion in inflamed cremaster muscle microvessels of mice treated with IC87114 compared with vehicle-treated mice. Furthermore, inhibition of PI3K p110δ significantly attenuated eotaxin-1-induced BM-Eos migration and prevented eotaxin-1-induced changes in the cytoskeleton and cell morphology. Knockdown of PI3K p110δ with siRNA in BM-Eos resulted in reduced rolling, adhesion, and migration, as well as inhibition of activation-induced changes in cell morphology, validating its role in regulating trafficking and migration. Finally, in a mouse model of cockroach antigen-induced allergic airway inflammation, oral administration of the PI3K p110δ inhibitor significantly inhibited airway eosinophil recruitment, resulting in attenuation of airway hyperresponsiveness in response to methacholine, reduced mucus secretion, and expression of proinflammatory molecules (found in inflammatory zone-1 and intelectin-1). Overall, these findings indicate the important role played by PI3K p110δ in mediating BM-Eos trafficking and migration by regulating adhesion molecule expression and localization/distribution as well as promoting changes in cell morphology that favor recruitment during inflammation.
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Affiliation(s)
- Bit Na Kang
- Laboratory of Allergic Diseases and Inflammation, Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, 55108, USA
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20
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Phosphoinositide phosphatase SHIP-1 regulates apoptosis induced by edelfosine, Fas ligation and DNA damage in mouse lymphoma cells. Biochem J 2011; 440:127-35. [DOI: 10.1042/bj20110125] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
S49 mouse lymphoma cells undergo apoptosis in response to the ALP (alkyl-lysophospholipid) edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine), FasL (Fas ligand) and DNA damage. S49 cells made resistant to ALP (S49AR) are defective in sphingomyelin synthesis and ALP uptake, and also have acquired resistance to FasL and DNA damage. However, these cells can be re-sensitized following prolonged culturing in the absence of ALP. The resistant cells show sustained ERK (extracellular-signal-regulated kinase)/Akt activity, consistent with enhanced survival signalling. In search of a common mediator of the observed cross-resistance, we found that S49AR cells lacked the PtdIns(3,4,5)P3 phosphatase SHIP-1 [SH2 (Src homology 2)-domain-containing inositol phosphatase 1], a known regulator of the Akt survival pathway. Re-sensitization of the S49AR cells restored SHIP-1 expression as well as phosphoinositide and sphingomyelin levels. Knockdown of SHIP-1 mimicked the S49AR phenotype in terms of apoptosis cross-resistance, sphingomyelin deficiency and altered phosphoinositide levels. Collectively, the results of the present study suggest that SHIP-1 collaborates with sphingomyelin synthase to regulate lymphoma cell death irrespective of the nature of the apoptotic stimulus.
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Lu S, Kim TJ, Chen CE, Ouyang M, Seong J, Liao X, Wang Y. Computational analysis of the spatiotemporal coordination of polarized PI3K and Rac1 activities in micro-patterned live cells. PLoS One 2011; 6:e21293. [PMID: 21738630 PMCID: PMC3124492 DOI: 10.1371/journal.pone.0021293] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 05/24/2011] [Indexed: 12/31/2022] Open
Abstract
Polarized molecular activities play important roles in guiding the cell toward persistent and directional migration. In this study, the polarized distributions of the activities of phosphatidylinositol 3-kinase (PI3K) and the Rac1 small GTPase were monitored using chimeric fluorescent proteins (FPs) in cells constrained on micro-patterned strips, with one end connecting to a neighboring cell (junction end) and the other end free of cell-cell contact (free end). The recorded spatiotemporal dynamics of the fluorescent intensity from different cells was scaled into a uniform coordinate system and applied to compute the molecular activity landscapes in space and time. The results revealed different polarization patterns of PI3K and Rac1 activity induced by the growth factor stimulation. The maximal intensity of different FPs, and the edge position and velocity at the free end were further quantified to analyze their correlation and decipher the underlying signaling sequence. The results suggest that the initiation of the edge extension occurred before the activation of PI3K, which led to a stable extension of the free end followed by the Rac1 activation. Therefore, the results support a concerted coordination of sequential signaling events and edge dynamics, underscoring the important roles played by PI3K activity at the free end in regulating the stable lamellipodia extension and cell migration. Meanwhile, the quantification methods and accompanying software developed can provide a convenient and powerful computational analysis platform for the study of spatiotemporal molecular distribution and hierarchy in live cells based on fluorescence images.
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Affiliation(s)
- Shaoying Lu
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America
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22
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Li D, Carr G, Zhang Y, Williams DE, Amlani A, Bottriell H, Mui ALF, Andersen RJ. Turnagainolides A and B, cyclic depsipeptides produced in culture by a Bacillus sp.: isolation, structure elucidation, and synthesis. JOURNAL OF NATURAL PRODUCTS 2011; 74:1093-9. [PMID: 21539394 DOI: 10.1021/np200033y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Two new cyclic depsipeptides, turnagainolides A (1) and B (2), have been isolated from laboratory cultures of a marine isolate of Bacillus sp. The structures of 1 and 2, which are simply epimers at the site of macrolactonization, were elucidated by analysis of NMR data and chemical degradation. A total synthesis of the turnagainolides confirmed their structures. Turnagainolide B (2) showed activity in a SHIP1 activation assay.
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Affiliation(s)
- Dehai Li
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
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23
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Harris SJ, Parry RV, Foster JG, Blunt MD, Wang A, Marelli-Berg F, Westwick J, Ward SG. Evidence That the Lipid Phosphatase SHIP-1 Regulates T Lymphocyte Morphology and Motility. THE JOURNAL OF IMMUNOLOGY 2011; 186:4936-45. [DOI: 10.4049/jimmunol.1002350] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Ward SG, Westwick J, Harris S. Sat-Nav for T cells: Role of PI3K isoforms and lipid phosphatases in migration of T lymphocytes. Immunol Lett 2011; 138:15-8. [PMID: 21333676 DOI: 10.1016/j.imlet.2011.02.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Phosphoinositide 3-kinase (PI3K)-dependent signaling has been placed at the heart of conserved biochemical mechanisms that facilitate cell migration of leukocytes in response to a range of chemoattractant stimuli. This review assesses the evidence for and against PI3K-dependent mechanisms of T lymphocyte migration and whether pharmacological targeting of PI3K isoforms is likely to offer potential benefit for T cell mediated pathologies.
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Affiliation(s)
- Stephen G Ward
- Department Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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25
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Francischetti IMB, Calvo E, Andersen JF, Pham VM, Favreau AJ, Barbian KD, Romero A, Valenzuela JG, Ribeiro JMC. Insight into the Sialome of the Bed Bug, Cimex lectularius. J Proteome Res 2010; 9:3820-31. [PMID: 20441151 DOI: 10.1021/pr1000169] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The evolution of insects to a blood diet leads to the development of a saliva that antagonizes their hosts' hemostasis and inflammation. Hemostasis and inflammation are redundant processes, and thus a complex salivary potion composed of dozens or near 100 different polypeptides is commonly found by transcriptome or proteome analysis of these organisms. Several insect orders or families evolved independently to hematophagy, creating unique salivary potions in the form of novel pharmacological use of endogenous substances and in the form of unique proteins not matching other known proteins, these probably arriving by fast evolution of salivary proteins as they evade their hosts' immune response. In this work we present a preliminary description of the sialome (from the Greek Sialo = saliva) of the common bed bug Cimex lectularius, the first such work from a member of the Cimicidae family. This manuscript is a guide for the supplemental database files http://exon.niaid.nih.gov/transcriptome/C_lectularius/S1/Cimex-S1.zip and http://exon.niaid.nih.gov/transcriptome/C_lectularius/S2/Cimex-S2.xls.
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Affiliation(s)
- Ivo M B Francischetti
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland 20852, USA
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26
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Deng Y, Johnson DR, Guan X, Ang CY, Ai J, Perkins EJ. In vitro gene regulatory networks predict in vivo function of liver. BMC SYSTEMS BIOLOGY 2010; 4:153. [PMID: 21073692 PMCID: PMC2998496 DOI: 10.1186/1752-0509-4-153] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 11/12/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Evolution of toxicity testing is predicated upon using in vitro cell based systems to rapidly screen and predict how a chemical might cause toxicity to an organ in vivo. However, the degree to which we can extend in vitro results to in vivo activity and possible mechanisms of action remains to be fully addressed. RESULTS Here we use the nitroaromatic 2,4,6-trinitrotoluene (TNT) as a model chemical to compare and determine how we might extrapolate from in vitro data to in vivo effects. We found 341 transcripts differentially expressed in common among in vitro and in vivo assays in response to TNT. The major functional term corresponding to these transcripts was cell cycle. Similarly modulated common pathways were identified between in vitro and in vivo. Furthermore, we uncovered the conserved common transcriptional gene regulatory networks between in vitro and in vivo cellular liver systems that responded to TNT exposure, which mainly contain 2 subnetwork modules: PTTG1 and PIR centered networks. Interestingly, all 7 genes in the PTTG1 module were involved in cell cycle and downregulated by TNT both in vitro and in vivo. CONCLUSIONS The results of our investigation of TNT effects on gene expression in liver suggest that gene regulatory networks obtained from an in vitro system can predict in vivo function and mechanisms. Inhibiting PTTG1 and its targeted cell cycle related genes could be key mechanism for TNT induced liver toxicity.
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Affiliation(s)
- Youping Deng
- Rush University Medical Center, Chicago, IL 60612, USA.
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Hamilton MJ, Ho VW, Kuroda E, Ruschmann J, Antignano F, Lam V, Krystal G. Role of SHIP in cancer. Exp Hematol 2010; 39:2-13. [PMID: 21056081 DOI: 10.1016/j.exphem.2010.11.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 09/30/2010] [Accepted: 11/02/2010] [Indexed: 12/19/2022]
Abstract
The SH2-containing inositol-5'-phosphatase, SHIP (or SHIP1), is a hematopoietic-restricted phosphatidylinositide phosphatase that translocates to the plasma membrane after extracellular stimulation and hydrolyzes the phosphatidylinositol-3-kinase-generated second messenger PI-3,4,5-P(3) to PI-3,4-P(2). As a result, SHIP dampens down PI-3,4,5-P(3)-mediated signaling and represses the proliferation, differentiation, survival, activation, and migration of hematopoietic cells. There are multiple lines of evidence suggesting that SHIP may act as a tumor suppressor during leukemogenesis and lymphomagenesis. Because of its ability to skew macrophage progenitors toward M1 macrophages and naïve T cells toward T helper 1 and T helper 17 cells, SHIP may play a critical role in activating the immune system to eradicate solid tumors. In this review, we will discuss the role of SHIP in hematopoietic cells and its therapeutic potential in terms of suppressing leukemias and lymphomas and manipulating the immune system to combat cancer.
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Affiliation(s)
- Melisa J Hamilton
- The Terry Fox Laboratory, BC Cancer Agency, Vancouver, British Columbia, Canada
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28
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Abstract
Second messenger molecules relay, amplify, and diversify cell surface receptor signals. Two important examples are phosphorylated D-myo-inositol derivatives, such as phosphoinositide lipids within cellular membranes, and soluble inositol phosphates. Here, we review how phosphoinositide metabolism generates multiple second messengers with important roles in T-cell development and function. They include soluble inositol(1,4,5)trisphosphate, long known for its Ca(2+)-mobilizing function, and phosphatidylinositol(3,4,5)trisphosphate, whose generation by phosphoinositide 3-kinase and turnover by the phosphatases PTEN and SHIP control a key "hub" of TCR signaling. More recent studies unveiled important second messenger functions for diacylglycerol, phosphatidic acid, and soluble inositol(1,3,4,5)tetrakisphosphate (IP(4)) in immune cells. Inositol(1,3,4,5)tetrakisphosphate acts as a soluble phosphatidylinositol(3,4,5)trisphosphate analog to control protein membrane recruitment. We propose that phosphoinositide lipids and soluble inositol phosphates (IPs) can act as complementary partners whose interplay could have broadly important roles in cellular signaling.
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Affiliation(s)
- Yina H Huang
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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29
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Zhang J, Ravichandran KS, Garrison JC. A key role for the phosphorylation of Ser440 by the cyclic AMP-dependent protein kinase in regulating the activity of the Src homology 2 domain-containing Inositol 5'-phosphatase (SHIP1). J Biol Chem 2010; 285:34839-49. [PMID: 20810657 DOI: 10.1074/jbc.m110.128827] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The Src homology 2 domain-containing inositol 5'-phosphatase 1 (SHIP1) dephosphorylates phosphatidylinositol 3,4,5-trisphosphate to phophatidylinositol 3,4-bisphosphate in hematopoietic cells to regulate multiple cell signaling pathways. SHIP1 can be phosphorylated by the cyclic AMP-dependent protein kinase (PKA), resulting in an increase in SHIP1 activity (Zhang, J., Walk, S. F., Ravichandran, K. S., and Garrison, J. C. (2009) J. Biol. Chem. 284, 20070-20078). Using a combination of approaches, we identified the serine residue regulating SHIP1 activity. After mass spectrometric identification of 17 serine and threonine residues on SHIP1 as being phosphorylated by PKA in vitro, studies with truncation mutants of SHIP1 narrowed the phosphorylation site to the catalytic region between residues 400 and 866. Of the two candidate phosphorylation sites located in this region (Ser(440) and Ser(774)), only mutation of Ser(440) to Ala abolished the ability of PKA to phosphorylate the purified, catalytic domain of SHIP1 (residues 401-866). Mutation of Ser(440) to Ala in full-length SHIP1 abrogated the ability of PKA to increase the activity of SHIP1 in mammalian cells. Using flow cytometry, we found that the PKA activator, Sp-adenosine 3',5'-cyclic monophosphorothioate triethylammonium salt hydrate (Sp-cAMPS) blunted the phosphorylation of Akt downstream of B cell antigen receptor engagement in SHIP1-null DT40 B lymphocytes expressing native mouse SHIP1. The inhibitory effect of Sp-cAMPS was absent in cells expressing the S440A mutant of SHIP1. These results suggest that activation of SHIP1 by PKA via phosphorylation on Ser(440) is an important regulatory event in hematopoietic cells.
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Affiliation(s)
- Jun Zhang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
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30
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Obar JJ, Lefrançois L. Early events governing memory CD8+ T-cell differentiation. Int Immunol 2010; 22:619-25. [PMID: 20504887 PMCID: PMC2908475 DOI: 10.1093/intimm/dxq053] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 05/07/2010] [Indexed: 01/10/2023] Open
Abstract
Understanding the regulation of the CD8(+) T-cell response and how protective memory cells are generated has been intensely studied. It is now appreciated that a naive CD8(+) T cell requires at least three signals to mount an effective immune response: (i) TCR triggering, (ii) co-stimulation and (iii) inflammatory cytokines. Only recently have we begun to understand the molecular integration of those signals and how early events regulate the fate decisions of the responding CD8(+) T cells. This review will discuss the recent findings about both the extracellular and intracellular factors that regulate the destiny of responding CD8(+) T cells.
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Affiliation(s)
- Joshua J Obar
- Center for Integrated Immunology and Vaccine Research, Department of Immunology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-1319, USA
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31
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Willox I, Mirkina I, Westwick J, Ward SG. Evidence for PI3K-dependent CXCR3 agonist-induced degranulation of human cord blood-derived mast cells. Mol Immunol 2010; 47:2367-77. [PMID: 20627397 DOI: 10.1016/j.molimm.2010.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Accepted: 05/05/2010] [Indexed: 11/18/2022]
Abstract
The chemokine receptor CXCR3, which has three known variants (CXCR3-A, CXCR3-B and CXCR3-Alt), has been implicated in the recruitment of mast cells to tissues in many different chronic diseases with its agonists found in elevated levels in several pulmonary diseases. All three variants of CXCR3 were detected in cord blood-derived mast cells at the mRNA level. Using an antibody that is unable to distinguish individual CXCR3 isoforms, we detected a marked down-regulation of intracellular protein during maturation from progenitor cells, with no concomitant changes in the modest surface expression of CXCR3. The known CXCR3 agonists CXCL9, CXCL10 and CXCL11 as well as the reported CXCR3-B agonist CXCL4, were able to induce Akt and ERK1/2 phosphorylation, as well as partial degranulation. Responses to all agonists were inhibited by pre-treatment with selective CXCR3 antagonists and pertussis toxin. Use of novel isoform-selective inhibitors, indicates that the p110 gamma isoform of PI3K is required for degranulation and signaling responses to CXCR3 agonists.
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Affiliation(s)
- Ian Willox
- Inflammatory Cell Biology Laboratory, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
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Zhang H, He J, Kutateladze TG, Sakai T, Sasaki T, Markadieu N, Erneux C, Prestwich GD. 5-Stabilized phosphatidylinositol 3,4,5-trisphosphate analogues bind Grp1 PH, inhibit phosphoinositide phosphatases, and block neutrophil migration. Chembiochem 2010; 11:388-95. [PMID: 20052709 DOI: 10.1002/cbic.200900545] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Metabolically stabilized analogues of PtdIns(3,4,5)P3 have shown long-lived agonist activity for cellular events and selective inhibition of lipid phosphatase activity. We describe an efficient asymmetric synthesis of two 5-phosphatase-resistant analogues of PtdIns(3,4,5)P3, the 5-methylene phosphonate (MP) and 5-phosphorothioate (PT). Furthermore, we illustrate the biochemical and biological activities of five stabilized PtdIns(3,4,5)P3 analogues in four contexts. First, the relative binding affinities of the 3-MP, 3-PT, 5-MP, 5-PT, and 3,4,5-PT3 analogues to the Grp1 PH domain are shown, as determined by NMR spectroscopy. Second, the enzymology of the five analogues is explored, showing the relative efficiency of inhibition of SHIP1, SHIP2, and phosphatase and tensin homologue deleted on chromosome 10 (PTEN), as well as the greatly reduced ability of these phosphatases to process these analogues as substrates as compared to PtdIns(3,4,5)P3. Third, exogenously delivered analogues severely impair complement factor C5a-mediated polarization and migration of murine neutrophils. Finally, the new analogues show long-lived agonist activity in mimicking insulin action in sodium transport in A6 cells.
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Affiliation(s)
- Honglu Zhang
- Department of Medicinal Chemistry, The University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, UT 84108-1257, USA
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Charlier E, Condé C, Zhang J, Deneubourg L, Di Valentin E, Rahmouni S, Chariot A, Agostinis P, Pang PC, Haslam SM, Dell A, Penninger J, Erneux C, Piette J, Gloire G. SHIP-1 inhibits CD95/APO-1/Fas-induced apoptosis in primary T lymphocytes and T leukemic cells by promoting CD95 glycosylation independently of its phosphatase activity. Leukemia 2010; 24:821-32. [PMID: 20147977 DOI: 10.1038/leu.2010.9] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 12/14/2009] [Accepted: 12/30/2009] [Indexed: 12/16/2022]
Abstract
SHIP-1 (SH2 (Src homology 2)-containing inositol 5'-phosphatase-1) functions as a negative regulator of immune responses by hydrolyzing phosphatidylinositol-3,4,5-triphosphate generated by phosphoinositide-3 (PI 3)-kinase activity. As a result, SHIP-1 deficiency in mice results in myeloproliferation and B-cell lymphoma. On the other hand, SHIP-1-deficient mice have a reduced T-cell population, but the underlying mechanisms are unknown. In this work, we hypothesized that SHIP-1 plays anti-apoptotic functions in T cells upon stimulation of the death receptor CD95/APO-1/Fas. Using primary T cells from SHIP-1(-/-) mice and T leukemic cell lines, we report that SHIP-1 is a potent inhibitor of CD95-induced death. We observed that a small fraction of the SHIP-1 pool is localized to the endoplasmic reticulum (ER), in which it promotes CD95 glycosylation. This post-translational modification requires an intact SH2 domain of SHIP-1, but is independent of its phosphatase activity. The glycosylated CD95 fails to oligomerize upon stimulation, resulting in impaired death-inducing signaling complex (DISC) formation and downstream apoptotic cascade. These results uncover an unanticipated inhibitory function for SHIP-1 and emphasize the role of glycosylation in the regulation of CD95 signaling in T cells. This work may also provide a new basis for therapeutic strategies using compounds inducing apoptosis through the CD95 pathway on SHIP-1-negative leukemic T cells.
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Affiliation(s)
- E Charlier
- Grappe Interdisciplinaire de Génoprotéomique Appliquée (GIGA)-Research, Signal Transduction Unit, Faculty of Sciences, University of Liège, Liège, Belgium
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Sauer K, Cooke MP. Regulation of immune cell development through soluble inositol-1,3,4,5-tetrakisphosphate. Nat Rev Immunol 2010; 10:257-71. [PMID: 20336153 PMCID: PMC2922113 DOI: 10.1038/nri2745] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The membrane lipid phosphatidylinositol-3,4,5-trisphosphate (PtdInsP(3)) regulates membrane receptor signalling in many cells, including immunoreceptor signalling. Here, we review recent data that have indicated essential roles for the soluble PtdInsP(3) analogue inositol-1,3,4,5-tetrakisphosphate (InsP(4)) in T cell, B cell and neutrophil development and function. Decreased InsP(4) production in leukocytes causes immunodeficiency in mice and might contribute to inflammatory vasculitis in Kawasaki disease in humans. InsP(4)-producing kinases could therefore provide attractive drug targets for inflammatory and infectious diseases.
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Affiliation(s)
- Karsten Sauer
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037, USA.
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35
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Finlay D, Cantrell D. Phosphoinositide 3-kinase and the mammalian target of rapamycin pathways control T cell migration. Ann N Y Acad Sci 2010; 1183:149-57. [PMID: 20146713 PMCID: PMC3520021 DOI: 10.1111/j.1749-6632.2009.05134.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The established role for phosphatidylinositol (3,4,5) triphosphate (PI(3,4,5)P3) signaling pathways is to regulate cell metabolism. More recently it has emerged that PI(3,4,5)P3 signaling via mammalian target of rapamycin and Foxo transcription factors also controls lymphocyte trafficking by determining the repertoire of adhesion and chemokine receptors expressed by T lymphocytes. In quiescent T cells, nonphosphorylated active Foxos maintain expression of KLF2, a transcription factor that regulates expression of the chemokine receptors CCR7 and sphingosine 1 phosphate receptor, and the adhesion receptor CD62L that together control T-cell transmigration into secondary lymphoid tissues. PI(3,4,5)P3 mediates activation of protein kinase B, which phosphorylates and inactivates Foxos, thereby terminating expression of KLF2 and its target genes. The correct localization of lymphocytes is essential for effective immune responses, and the ability of phosphoinositide 3-kinase and mammalian target of rapamycin to regulate expression of chemokine receptors and adhesion molecules puts these signaling molecules at the core of the molecular mechanisms that control lymphocyte trafficking.
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Affiliation(s)
- David Finlay
- Division of Immunology and Cell Biology, University of Dundee, Dundee, UK
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Best MD, Zhang H, Prestwich GD. Inositol polyphosphates, diphosphoinositol polyphosphates and phosphatidylinositol polyphosphate lipids: Structure, synthesis, and development of probes for studying biological activity. Nat Prod Rep 2010; 27:1403-30. [DOI: 10.1039/b923844c] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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37
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Activation of SHIP via a small molecule agonist kills multiple myeloma cells. Exp Hematol 2009; 37:1274-83. [DOI: 10.1016/j.exphem.2009.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Revised: 08/04/2009] [Accepted: 08/18/2009] [Indexed: 11/22/2022]
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Zhu W, Trivedi CM, Zhou D, Yuan L, Lu MM, Epstein JA. Inpp5f is a polyphosphoinositide phosphatase that regulates cardiac hypertrophic responsiveness. Circ Res 2009; 105:1240-7. [PMID: 19875726 DOI: 10.1161/circresaha.109.208785] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Cardiac hypertrophy occurs in response to a variety of extrinsic and intrinsic stimuli that impose increased biomechanical stress. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway has previously been strongly associated with hypertrophic signaling in the heart, and with the control of cell size in multiple contexts. This pathway is tightly regulated by many factors, including a host of kinases and phosphatases that function at multiple steps in the signaling cascade. For example, the PTEN (phosphatase and tensin homolog) tumor suppressor protein is a phosphoinositide 3-phosphatase that, by metabolizing phosphatidylinositol 3,4,5-trisphosphate (PtdIns[3,4,5]P(3), PIP3), acts in direct antagonism to growth factor-stimulated PI3K. Inhibition of PTEN leads to cardiomyocyte hypertrophy. Another polyphoinositide phosphatase, inositol polyphosphate-5-phosphatase F (Inpp5f) has recently been implicated in regulation of cardiac hypertrophy. Like PTEN, this phosphatase can degrade PtdIns(3,4,5)P(3) and thus modulates the PI3K/Akt pathway. OBJECTIVE To characterize the role of Inpp5f in regulating cardiac hypertrophy. METHODS AND RESULTS We generated homozygous Inpp5f knockout mice and cardiac specific Inpp5f overexpression transgenic mice. We evaluated their hearts for biochemical, structural and functional changes. Inpp5f knockout mice have augmented hypertrophy and reactivation of the fetal gene program in response to stress when compared to wild-type littermates. Furthermore, cardiac overexpression of Inpp5f in transgenic mice reduces hypertrophic responsiveness. CONCLUSIONS Our results suggest that Inpp5f is a functionally important endogenous modulator of cardiac myocyte size and of the cardiac response to stress.
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Affiliation(s)
- Wenting Zhu
- 1154 BRB II, University of Pennsylvania, 421 Curie Blvd, Philadelphia PA 19104.
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Abstract
Chronic urticaria is a common skin disease without an etiology in the majority of cases. The similarity of symptoms and pathology to allergen-induced skin reactions supports the idea that skin mast cell and blood basophil IgE receptor activation is involved; however, no exogenous allergen trigger has been identified. Recent evidence supports a role for blood basophils in disease expression. Specifically, blood basopenia is noted in active disease with the recruitment of blood basophils to skin lesional sites. In addition, blood basophils display altered IgE receptor-mediated degranulation that reverts in disease remission. In active chronic idiopathic urticaria (CIU) subjects, changes in IgE receptor-signaling molecule expression levels accompany the altered degranulation function in blood basophils. The arrival of therapies targeting IgE has further shown that altered blood basophil degranulation behavior has potential use as a disease biomarker in CIU.
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Abstract
SUMMARY Programmed death-1 (PD-1) is a cell surface molecule that regulates the adaptive immune response. Engagement of PD-1 by its ligands PD-L1 or PD-L2 transduces a signal that inhibits T-cell proliferation, cytokine production, and cytolytic function. While a great deal is known concerning the biologic roles PD-1 plays in regulating the primary immune response and in T-cell exhaustion, comparatively little is known regarding how PD-1 ligation alters signaling pathways. PD-1 ligation is known to inhibit membrane-proximal T-cell signaling events, while ligation of the related inhibitory molecule cytotoxic T-lymphocyte antigen-4 appears to target more downstream signaling pathways. A major obstacle to an in-depth understanding of PD-1 signaling is the lack of physiologic models in which to study signal transduction. This review focuses on: (i) signaling pathways altered by PD-1 ligation, (ii) factors recruited upon PD-1 phosphorylation, and (iii) exploring the hypothesis that PD-1 ligation induces distinct signals during various stages of immune-cell differentiation. Lastly, we describe models to dissect the function of the PD-1 cytoplasmic tail using primary cells in the absence of agonist antibodies.
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Affiliation(s)
- James L Riley
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, The University of Pennsylvania, Philadelphia, PA, USA.
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Locke NR, Patterson SJ, Hamilton MJ, Sly LM, Krystal G, Levings MK. SHIP Regulates the Reciprocal Development of T Regulatory and Th17 Cells. THE JOURNAL OF IMMUNOLOGY 2009; 183:975-83. [DOI: 10.4049/jimmunol.0803749] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Li L, Saga N, Mikami K. Ca2+ influx and phosphoinositide signalling are essential for the establishment and maintenance of cell polarity in monospores from the red alga Porphyra yezoensis. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:3477-89. [PMID: 19531546 PMCID: PMC2724695 DOI: 10.1093/jxb/erp183] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 05/12/2009] [Accepted: 05/13/2009] [Indexed: 05/16/2023]
Abstract
The asymmetrical distribution of F-actin directed by cell polarity has been observed during the migration of monospores from the red alga Porphyra yezoensis. The significance of Ca2+ influx and phosphoinositide signalling during the formation of cell polarity in migrating monospores was analysed pharmacologically. The results indicate that the inhibition of the establishment of cell polarity, as judged by the ability of F-actin to localize asymmetrically, cell wall synthesis, and development into germlings, occurred when monospores were treated with inhibitors of the Ca2+ permeable channel, phospholipase C (PLC), diacylglycerol kinase, and inositol-1,4,5-trisphosphate receptor. Moreover, it was also found that light triggered the establishment of cell polarity via photosynthetic activity but not its direction, indicating that the Ca2+ influx and PLC activation required for the establishment of cell polarity are light dependent. By contrast, inhibition of phospholipase D (PLD) prevented the migration of monospores but not the asymmetrical localization of F-actin. Taken together, these findings suggest that there is functional diversity between the PLC and PLD signalling systems in terms of the formation of cell polarity; the former being critical for the light-dependent establishment of cell polarity and the latter playing a role in the maintenance of established cell polarity.
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Affiliation(s)
- Lin Li
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
| | - Naotsune Saga
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan
| | - Koji Mikami
- Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan
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Saini SS, Paterniti M, Vasagar K, Gibbons SP, Sterba PM, Vonakis BM. Cultured peripheral blood mast cells from chronic idiopathic urticaria patients spontaneously degranulate upon IgE sensitization: Relationship to expression of Syk and SHIP-2. Clin Immunol 2009; 132:342-8. [PMID: 19477690 DOI: 10.1016/j.clim.2009.05.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 05/01/2009] [Accepted: 05/02/2009] [Indexed: 11/25/2022]
Abstract
Recently, signaling changes in the FcvarepsilonRI pathway involving inositol lipid phosphatases have been identified in the basophils of chronic idiopathic urticaria (CIU) subjects. Based on the profile of basophil FcvarepsilonRI-mediated histamine degranulation, we have segregated CIU subjects into two groups, CIU Responder (CIU R) or CIU Nonresponder (CIU NR). In the present study, we compared expression of SHIP-1, SHIP-2, and Syk protein to histamine release (HR) from mast cells (MC) cultured from the peripheral blood of CIU R, CIU NR, and normal subjects. The MC of CIU R donors contained significantly increased Syk and decreased SHIP-2 as compared to CIU NR (Syk: p=0.038, SHIP-2: p=0.038) and normals (Syk: p=0.042, SHIP-2: p=0.027). Spontaneous HR from CIU donors was increased two-fold compared to normals (p=0.04). In summary, our results suggest a possible predilection for urticarial MC to spontaneously degranulate upon IgE sensitization contributing to the increased pruritus associated with CIU.
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Affiliation(s)
- Sarbjit S Saini
- Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, Baltimore MD 21224, USA
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Lo TCT, Barnhill LM, Kim Y, Nakae EA, Yu AL, Diccianni MB. Inactivation of SHIP1 in T-cell acute lymphoblastic leukemia due to mutation and extensive alternative splicing. Leuk Res 2009; 33:1562-6. [PMID: 19473701 DOI: 10.1016/j.leukres.2009.04.032] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 04/16/2009] [Accepted: 04/23/2009] [Indexed: 11/17/2022]
Abstract
To understand the mechanism behind aberrant Akt activation in T-ALL, PIK3CA, PTEN and SHIP1 expression and genotype were assessed. No cell lines or primary ALLs harbored PIK3CA mutations. PTEN was expressed in just one-third of the cell lines, but in two-thirds of the primary ALLs, though in the inactivated (phosphorylated) form. SHIP1 was undetectable in most primary ALL and in the T-ALL cell line Jurkat, which harbored a bi-allelic null mutation and a frame-shift deletion; primary ALL harbored the frame-shift as well as other translationally-inactivating deletions and insertions. The inactivation of SHIP1 could play a central role in the deregulation of Akt pathway and tumorigenesis, perhaps in conjunction with PTEN inactivation.
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Affiliation(s)
- Tony C T Lo
- Department of Pediatrics Hematology/Oncology, University of California at San Diego, San Diego, CA 92103-8447, United States
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The role of the inositol polyphosphate 5-phosphatases in cellular function and human disease. Biochem J 2009; 419:29-49. [PMID: 19272022 DOI: 10.1042/bj20081673] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Phosphoinositides are membrane-bound signalling molecules that regulate cell proliferation and survival, cytoskeletal reorganization and vesicular trafficking by recruiting effector proteins to cellular membranes. Growth factor or insulin stimulation induces a canonical cascade resulting in the transient phosphorylation of PtdIns(4,5)P(2) by PI3K (phosphoinositide 3-kinase) to form PtdIns(3,4,5)P(3), which is rapidly dephosphorylated either by PTEN (phosphatase and tensin homologue deleted on chromosome 10) back to PtdIns(4,5)P(2), or by the 5-ptases (inositol polyphosphate 5-phosphatases), generating PtdIns(3,4)P(2). The 5-ptases also hydrolyse PtdIns(4,5)P(2), forming PtdIns4P. Ten mammalian 5-ptases have been identified, which share a catalytic mechanism similar to that of the apurinic/apyrimidinic endonucleases. Gene-targeted deletion of 5-ptases in mice has revealed that these enzymes regulate haemopoietic cell proliferation, synaptic vesicle recycling, insulin signalling, endocytosis, vesicular trafficking and actin polymerization. Several studies have revealed that the molecular basis of Lowe's syndrome is due to mutations in the 5-ptase OCRL (oculocerebrorenal syndrome of Lowe). Futhermore, the 5-ptases SHIP [SH2 (Src homology 2)-domain-containing inositol phosphatase] 2, SKIP (skeletal muscle- and kidney-enriched inositol phosphatase) and 72-5ptase (72 kDa 5-ptase)/Type IV/Inpp5e (inositol polyphosphate 5-phosphatase E) are implicated in negatively regulating insulin signalling and glucose homoeostasis in specific tissues. SHIP2 polymorphisms are associated with a predisposition to insulin resistance. Gene profiling studies have identified changes in the expression of various 5-ptases in specific cancers. In addition, 5-ptases such as SHIP1, SHIP2 and 72-5ptase/Type IV/Inpp5e regulate macrophage phagocytosis, and SHIP1 also controls haemopoietic cell proliferation. Therefore the 5-ptases are a significant family of signal-modulating enzymes that govern a plethora of cellular functions by regulating the levels of specific phosphoinositides. Emerging studies have implicated their loss or gain of function in human disease.
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Abstract
T-lymphocyte trafficking is targeted to specific organs by selective molecular interactions depending on their differentiation and functional properties. Specific chemokine receptors have been associated with organ-specific trafficking of memory and effector T-cells, as well as the recirculation of naïve T-cells to secondary lymphoid organs. In addition to the acquisition of tissue-selective integrins and chemokine receptors, an additional level of specificity for T-cell trafficking into the tissue is provided by specific recognition of antigen displayed by the endothelium involving the TCRs (T-cell antigen receptors) and co-stimulatory receptors. Activation of PI3K (phosphoinositide 3-kinase) is a robust signalling event shared by most chemokine receptors as well as the TCR and co-stimulatory receptors, contributing to several aspects of T-lymphocyte homing as well as actin reorganization and other components of the general migratory machinery. Accordingly, inhibition of PI3K has been considered seriously as a potential therapeutic strategy by which to combat various T-lymphocyte-dependent pathologies, including autoimmune and inflammatory diseases, as well as to prevent transplant rejection. However, there is substantial evidence for PI3K-independent mechanisms that facilitate T-lymphocyte migration. In this regard, several other signalling-pathway components, including small GTPases, PLC (phospholipase C) and PKC (protein kinase C) isoforms, have also been implicated in T-lymphocyte migration in response to chemokine stimulation. The present review will therefore examine the PI3K-dependent and -independent signal-transduction pathways involved in T-cell migration during distinct modes of T-cell trafficking in response to either chemokines or the TCR and co-stimulatory molecules.
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Acuto O, Di Bartolo V, Michel F. Tailoring T-cell receptor signals by proximal negative feedback mechanisms. Nat Rev Immunol 2009; 8:699-712. [PMID: 18728635 DOI: 10.1038/nri2397] [Citation(s) in RCA: 196] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The T-cell receptor (TCR) signalling machinery is central in determining the response of a T cell (establishing immunity or tolerance) following exposure to antigen. This process is made difficult by the narrow margin of self and non-self discrimination, and by the complexity of the genetic programmes that are induced for each outcome. Recent studies have identified novel negative feedback mechanisms that are rapidly induced by TCR engagement and that have key roles in the regulation of signal triggering and propagation. In vitro and in vivo data suggest that they are important in determining ligand discrimination by the TCR and in regulating signal output in response to antigen.
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Affiliation(s)
- Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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Kim HJ, Triplett B. Involvement of extracellular Cu/Zn superoxide dismutase in cotton fiber primary and secondary cell wall biosynthesis. PLANT SIGNALING & BEHAVIOR 2008; 3:1119-21. [PMID: 19704453 PMCID: PMC2634474 DOI: 10.4161/psb.3.12.7039] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 09/17/2008] [Indexed: 05/24/2023]
Abstract
Extracellular Cu/Zn superoxide dismutases (CSDs) that catalyze the conversion of superoxide to hydrogen peroxide have been suggested to be involved in lignification of secondary walls in spinach, pine and aspen. In cotton fibers, hydrogen peroxide was proposed to be involved in the induction of secondary cell wall biosynthesis. Recently, we identified extracellular CSDs from developing cotton fibers using both immunological and epitope tagging techniques. Since cotton fibers are not lignified, we suggested that extracellular CSDs may be involved in plant cell wall growth and development processes other than lignification. In this addendum, we have further characterized the extracellular CSD in cotton fiber. Immunoblots, enzyme activity assays, and transcript levels show that an extracellular CSD is present in elongating primary walls as well as thickening secondary walls of cotton fibers. Our working model proposes that extracellular hydrogen peroxide levels, regulated by redox status-related enzymes including extracellular CSDs and peroxidases, may affect the processes of wall loosening and wall tightening.
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Affiliation(s)
- Hee Jin Kim
- University of New Orleans; New Orleans, Louisiana USA
| | - Barbara Triplett
- United States Department of Agriculture—Agricultual Research Service; Southern Regional Research Center; New Orleans, Louisiana USA
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50
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Vonakis BM, Saini SS. New concepts in chronic urticaria. Curr Opin Immunol 2008; 20:709-16. [PMID: 18832031 DOI: 10.1016/j.coi.2008.09.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 09/19/2008] [Indexed: 12/19/2022]
Abstract
Chronic urticaria is a common skin disease without a clear etiology in the vast majority of cases. The similarity of symptoms and lesion pathology to allergen-induced skin reactions supports the idea that skin mast cell and blood basophil IgE receptor activation is involved; however, no exogenous allergen trigger has been identified. The presence of serum IgG autoantibodies targeting IgE or the IgE receptor in approximately 40% of CIU cases supports the theory of an autoimmune basis for the disease. However, issues remain with the assays to detect autoantibodies among other serum factors, the relationship of autoantibodies to CIU disease activity, and the occurrence of autoantibodies in healthy subjects. Other studies have identified altered IgE receptor degranulation that reverts in disease remission and is accompanied by changes in signaling molecule expression and function in mast cells and basophils in active CIU subjects. The arrival of therapies targeting IgE and the IgE receptor pathway elements has potential use in CIU.
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Affiliation(s)
- Becky M Vonakis
- Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, United States
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