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Chen X, Obukhov AG, Weisman GA, Seye CI. Basal ATP release signals through the P2Y 2 receptor to maintain the differentiated phenotype of vascular smooth muscle cells. Atherosclerosis 2024; 395:117613. [PMID: 38889566 PMCID: PMC11254552 DOI: 10.1016/j.atherosclerosis.2024.117613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 05/30/2024] [Accepted: 05/30/2024] [Indexed: 06/20/2024]
Abstract
BACKGROUND AND AIMS Vascular smooth muscle cell (VSMC) dedifferentiation contributes substantively to vascular disease. VSMCs spontaneously release low levels of ATP that modulate vessel contractility, but it is unclear if autocrine ATP signaling in VSMCs is critical to the maintenance of the VSMC contractile phenotype. METHODS We used pharmacological inhibitors to block ATP release in human aortic smooth muscle cells (HASMCs) for studying changes in VSMC differentiation marker gene expression. We employed RNA interference and generated mice with SMC-specific inducible deletion of the P2Y2 receptor (P2Y2R) gene to evaluate resulting phenotypic alterations. RESULTS HASMCs constitutively release low levels of ATP that when blocked results in a significant decrease in VSMC differentiation marker gene expression, including smooth muscle actin (SMA), smooth muscle myosin heavy chain (SMMHC), SM-22α and calponin. Basal release of ATP represses transcriptional activation of the Krüppel-Like Factor 4 (KFL4) thereby preventing platelet-derived growth factor-BB (PDGF-BB) from inhibiting expression of SMC contractile phenotype markers. SMC-restricted conditional deletion of P2Y2R evoked dedifferentiation characterized by decreases in aortic contractility and contractile phenotype markers expression. This loss was accompanied by a transition to the synthetic phenotype with the acquisition of extracellular matrix (ECM) proteins characteristic of dedifferentiation, such as osteopontin and vimentin. CONCLUSIONS Our data establish the first direct evidence that an autocrine ATP release mechanism maintains SMC cytoskeletal protein expression by inhibiting VSMCs from transitioning to a synthetic phenotype, and further demonstrate that activation of the P2Y2R by basally released ATP is required for maintenance of the differentiated VSMC phenotype.
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Affiliation(s)
- Xingjuan Chen
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, 710072, China; Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, 635 Barnhill Drive MS 360A, Indianapolis, IN, 46202, USA
| | - Alexander G Obukhov
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, 635 Barnhill Drive MS 360A, Indianapolis, IN, 46202, USA
| | - Gary A Weisman
- Department of Biochemistry, Christopher S. Bond Life Sciences Center, University of Missouri, 1201 Rollins Road, Columbia, MO, 65211, USA
| | - Cheikh I Seye
- Department of Biochemistry, Christopher S. Bond Life Sciences Center, University of Missouri, 1201 Rollins Road, Columbia, MO, 65211, USA.
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Zhou Q, Liu S, Kou Y, Yang P, Liu H, Hasegawa T, Su R, Zhu G, Li M. ATP Promotes Oral Squamous Cell Carcinoma Cell Invasion and Migration by Activating the PI3K/AKT Pathway via the P2Y2-Src-EGFR Axis. ACS OMEGA 2022; 7:39760-39771. [PMID: 36385800 PMCID: PMC9648055 DOI: 10.1021/acsomega.2c03727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Oral cancer is one of the most common malignancies of the head and neck, and approximately 90% of oral cancers are oral squamous cell carcinomas (OSCCs). The purinergic P2Y2 receptor is upregulated in breast cancer, pancreatic cancer, colorectal cancer, and liver cancer, but its role in OSCC is still unclear. Here, we examined the effects of P2Y2 on the invasion and migration of oral cancer cells (SCC15 and CAL27). The BALB/c mouse model was used to observe the involvement of P2Y2 with tumors in vivo. P2Y2, Src, and EGFR are highly expressed in OSCC tissues and cell lines. Stimulation with ATP significantly enhanced cell invasion and migration in oral cancer cells, and enhanced the activity of Src and EGFR protein kinases, which is mediated by the PI3K/AKT signaling pathway. P2Y2 knockdown attenuated the above ATP-driven events in vitro and in vivo. The PI3K/AKT signaling pathway was blocked by Src or EGFR inhibitor. Extracellular ATP activates the PI3K/AKT pathway through the P2Y2-Src-EGFR axis to promote OSCC invasion and migration, and thus, P2Y2 may be a potential novel target for antimetastasis therapy.
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Affiliation(s)
- Qin Zhou
- Department
of Bone Metabolism, School and Hospital of Stomatology, Cheeloo College
of Medicine, Shandong University and Shandong
Key Laboratory of Oral Tissue Regeneration and Shandong Engineering
Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250100, China
- Center
of Osteoporosis and Bone Mineral Research, Shandong University, Jinan 250100, China
| | - Shanshan Liu
- Department
of Bone Metabolism, School and Hospital of Stomatology, Cheeloo College
of Medicine, Shandong University and Shandong
Key Laboratory of Oral Tissue Regeneration and Shandong Engineering
Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250100, China
- Center
of Osteoporosis and Bone Mineral Research, Shandong University, Jinan 250100, China
| | - Yuying Kou
- Department
of Bone Metabolism, School and Hospital of Stomatology, Cheeloo College
of Medicine, Shandong University and Shandong
Key Laboratory of Oral Tissue Regeneration and Shandong Engineering
Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250100, China
- Center
of Osteoporosis and Bone Mineral Research, Shandong University, Jinan 250100, China
| | - Panpan Yang
- Department
of Bone Metabolism, School and Hospital of Stomatology, Cheeloo College
of Medicine, Shandong University and Shandong
Key Laboratory of Oral Tissue Regeneration and Shandong Engineering
Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250100, China
- Center
of Osteoporosis and Bone Mineral Research, Shandong University, Jinan 250100, China
| | - Hongrui Liu
- Department
of Bone Metabolism, School and Hospital of Stomatology, Cheeloo College
of Medicine, Shandong University and Shandong
Key Laboratory of Oral Tissue Regeneration and Shandong Engineering
Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250100, China
- Center
of Osteoporosis and Bone Mineral Research, Shandong University, Jinan 250100, China
| | - Tomoka Hasegawa
- Department
of Developmental Biology of Hard Tissue, Graduate School of Dental
Medicine, Hokkaido University, Sapporo 060-0808, Japan
| | - Rongjian Su
- College
of Basic Medicine of Jinzhou Medical University, Cell Biology and
Genetic Department of Jinzhou Medical University, Key Lab of Molecular
and Cellular Biology of the Education Department of Liaoning Province, Life Science Institute of Jinzhou Medical University, Jinzhou 121001, China
| | - Guoxiong Zhu
- Department
of Stomatology, No.960 Hospital of PLA, No. 25 Shifan Road, Jinan 250014, China
| | - Minqi Li
- Department
of Bone Metabolism, School and Hospital of Stomatology, Cheeloo College
of Medicine, Shandong University and Shandong
Key Laboratory of Oral Tissue Regeneration and Shandong Engineering
Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan 250100, China
- Center
of Osteoporosis and Bone Mineral Research, Shandong University, Jinan 250100, China
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Jasmer KJ, Muñoz Forti K, Woods LT, Cha S, Weisman GA. Therapeutic potential for P2Y 2 receptor antagonism. Purinergic Signal 2022:10.1007/s11302-022-09900-3. [PMID: 36219327 DOI: 10.1007/s11302-022-09900-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/22/2022] [Indexed: 10/17/2022] Open
Abstract
G protein-coupled receptors are the target of more than 30% of all FDA-approved drug therapies. Though the purinergic P2 receptors have been an attractive target for therapeutic intervention with successes such as the P2Y12 receptor antagonist, clopidogrel, P2Y2 receptor (P2Y2R) antagonism remains relatively unexplored as a therapeutic strategy. Due to a lack of selective antagonists to modify P2Y2R activity, studies using primarily genetic manipulation have revealed roles for P2Y2R in a multitude of diseases. These include inflammatory and autoimmune diseases, fibrotic diseases, renal diseases, cancer, and pathogenic infections. With the advent of AR-C118925, a selective and potent P2Y2R antagonist that became commercially available only a few years ago, new opportunities exist to gain a more robust understanding of P2Y2R function and assess therapeutic effects of P2Y2R antagonism. This review discusses the characteristics of P2Y2R that make it unique among P2 receptors, namely its involvement in five distinct signaling pathways including canonical Gαq protein signaling. We also discuss the effects of other P2Y2R antagonists and the pivotal development of AR-C118925. The remainder of this review concerns the mounting evidence implicating P2Y2Rs in disease pathogenesis, focusing on those studies that have evaluated AR-C118925 in pre-clinical disease models.
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Affiliation(s)
- Kimberly J Jasmer
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.,Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Kevin Muñoz Forti
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.,Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Lucas T Woods
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.,Department of Biochemistry, University of Missouri, Columbia, MO, USA
| | - Seunghee Cha
- Department of Oral and Maxillofacial Diagnostic Sciences, Center for Orphaned Autoimmune Disorders, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Gary A Weisman
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA. .,Department of Biochemistry, University of Missouri, Columbia, MO, USA.
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Purinergic P2Y2 and P2X4 Receptors Are Involved in the Epithelial-Mesenchymal Transition and Metastatic Potential of Gastric Cancer Derived Cell Lines. Pharmaceutics 2021; 13:pharmaceutics13081234. [PMID: 34452195 PMCID: PMC8398939 DOI: 10.3390/pharmaceutics13081234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/07/2021] [Accepted: 08/09/2021] [Indexed: 12/14/2022] Open
Abstract
Gastric cancer (GC) is a major health concern worldwide, presenting a complex pathophysiology that has hindered many therapeutic efforts so far. In this context, purinergic signaling emerges as a promising pathway for intervention due to its known role in cancer cell proliferation and migration. In this work, we explored in more detail the role of purinergic signaling in GC with several experimental approaches. First, we measured extracellular ATP concentrations on GC-derived cell lines (AGS, MKN-45, and MKN-74), finding higher levels of extracellular ATP than those obtained for the non-tumoral gastric cell line GES-1. Next, we established the P2Y2 and P2X4 receptors (P2Y2R and P2X4R) expression profile on these cells and evaluated their role on cell proliferation and migration after applying overexpression and knockdown strategies. In general, a P2Y2R overexpression and P2X4R downregulation pattern were observed on GC cell lines, and when these patterns were modified, concomitant changes in cell viability were observed. These modifications on gene expression also modified transepithelial electrical resistance (TEER), showing that higher P2Y2R levels decreased TEER, and high P2X4R expression had the opposite effect, suggesting that P2Y2R and P2X4R activation could promote and suppress epithelial-mesenchymal transition (EMT), respectively. These effects were confirmed after treating AGS cells with UTP, a P2Y2R-agonist that modified the expression patterns towards mesenchymal markers. To further characterize the effects of P2Y2R activation on EMT, we used cDNA microarrays and observed that UTP induced important transcriptional changes on several cell processes like cell proliferation induction, apoptosis inhibition, cell differentiation induction, and cell adhesion reduction. These results suggest that purinergic signaling plays a complex role in GC pathophysiology, and changes in purinergic balance can trigger tumorigenesis in non-tumoral gastric cells.
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Woods LT, Forti KM, Shanbhag VC, Camden JM, Weisman GA. P2Y receptors for extracellular nucleotides: Contributions to cancer progression and therapeutic implications. Biochem Pharmacol 2021; 187:114406. [PMID: 33412103 DOI: 10.1016/j.bcp.2021.114406] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 12/31/2020] [Indexed: 12/16/2022]
Abstract
Purinergic receptors for extracellular nucleotides and nucleosides contribute to a vast array of cellular and tissue functions, including cell proliferation, intracellular and transmembrane ion flux, immunomodulation and thrombosis. In mammals, the purinergic receptor system is composed of G protein-coupled P1 receptors A1, A2A, A2B and A3 for extracellular adenosine, P2X1-7 receptors that are ATP-gated ion channels and G protein-coupled P2Y1,2,4,6,11,12,13 and 14 receptors for extracellular ATP, ADP, UTP, UDP and/or UDP-glucose. Recent studies have implicated specific P2Y receptor subtypes in numerous oncogenic processes, including cancer tumorigenesis, metastasis and chemotherapeutic drug resistance, where G protein-mediated signaling cascades modulate intracellular ion concentrations and activate downstream protein kinases, Src family kinases as well as numerous mitogen-activated protein kinases. We are honored to contribute to this special issue dedicated to the founder of the field of purinergic signaling, Dr. Geoffrey Burnstock, by reviewing the diverse roles of P2Y receptors in the initiation, progression and metastasis of specific cancers with an emphasis on pharmacological and genetic strategies employed to delineate cell-specific and P2Y receptor subtype-specific responses that have been investigated using in vitro and in vivo cancer models. We further highlight bioinformatic and empirical evidence on P2Y receptor expression in human clinical specimens and cover clinical perspectives where P2Y receptor-targeting interventions may have therapeutic relevance to cancer treatment.
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Affiliation(s)
- Lucas T Woods
- Department of Biochemistry, University of Missouri, Columbia, MO, USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Kevin Muñoz Forti
- Department of Biochemistry, University of Missouri, Columbia, MO, USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Vinit C Shanbhag
- Department of Biochemistry, University of Missouri, Columbia, MO, USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Jean M Camden
- Department of Biochemistry, University of Missouri, Columbia, MO, USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Gary A Weisman
- Department of Biochemistry, University of Missouri, Columbia, MO, USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.
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Woods LT, Jasmer KJ, Muñoz Forti K, Shanbhag VC, Camden JM, Erb L, Petris MJ, Weisman GA. P2Y 2 receptors mediate nucleotide-induced EGFR phosphorylation and stimulate proliferation and tumorigenesis of head and neck squamous cell carcinoma cell lines. Oral Oncol 2020; 109:104808. [PMID: 32540611 PMCID: PMC7736485 DOI: 10.1016/j.oraloncology.2020.104808] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 04/16/2020] [Accepted: 05/15/2020] [Indexed: 02/07/2023]
Abstract
OBJECTIVES To assess functional expression of the P2Y2 nucleotide receptor (P2Y2R) in head and neck squamous cell carcinoma (HNSCC) cell lines and define its role in nucleotide-induced epidermal growth factor receptor (EGFR) transactivation. The use of anti-EGFR therapeutics to treat HNSCC is hindered by intrinsic and acquired drug resistance. Defining novel pathways that modulate EGFR signaling could identify additional targets to treat HNSCC. MATERIALS AND METHODS In human HNSCC cell lines CAL27 and FaDu and the mouse oral cancer cell line MOC2, P2Y2R contributions to extracellular nucleotide-induced changes in intracellular free Ca2+ concentration and EGFR and extracellular signal-regulated kinase (ERK1/2) phosphorylation were determined using the ratiometric Ca2+ indicator fura-2 and immunoblot analysis, respectively. Genetic knockout of P2Y2Rs using CRISPR technology or pharmacological inhibition with P2Y2R-selective antagonist AR-C118925 defined P2Y2R contributions to in vivo tumor growth. RESULTS P2Y2R agonists UTP and ATP increased intracellular Ca2+ levels and ERK1/2 and EGFR phosphorylation in CAL27 and FaDu cells, responses that were inhibited by AR-C118925 or P2Y2R knockout. P2Y2R-mediated EGFR phosphorylation was also attenuated by inhibition of the adamalysin family of metalloproteases or Src family kinases. P2Y2R knockout reduced UTP-induced CAL27 cell proliferation in vitro and significantly reduced CAL27 and FaDu tumor xenograft volume in vivo. In a syngeneic mouse model of oral cancer, AR-C118925 administration reduced MOC2 tumor volume. CONCLUSION P2Y2Rs mediate HNSCC cell responses to extracellular nucleotides and genetic or pharmacological blockade of P2Y2R signaling attenuates tumor cell proliferation and tumorigenesis, suggesting that the P2Y2R represents a novel therapeutic target in HNSCC.
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Affiliation(s)
- Lucas T Woods
- Division of Biochemistry, University of Missouri, Columbia, MO 65211-7310 USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 USA
| | - Kimberly J Jasmer
- Division of Biochemistry, University of Missouri, Columbia, MO 65211-7310 USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 USA
| | - Kevin Muñoz Forti
- Division of Biochemistry, University of Missouri, Columbia, MO 65211-7310 USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 USA
| | - Vinit C Shanbhag
- Division of Biochemistry, University of Missouri, Columbia, MO 65211-7310 USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 USA
| | - Jean M Camden
- Division of Biochemistry, University of Missouri, Columbia, MO 65211-7310 USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 USA
| | - Laurie Erb
- Division of Biochemistry, University of Missouri, Columbia, MO 65211-7310 USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 USA
| | - Michael J Petris
- Division of Biochemistry, University of Missouri, Columbia, MO 65211-7310 USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 USA; Department of Ophthalmology, University of Missouri School of Medicine, Columbia, MO 65211-7310 USA
| | - Gary A Weisman
- Division of Biochemistry, University of Missouri, Columbia, MO 65211-7310 USA; Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 USA.
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7
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Thompson BJ. YAP/TAZ: Drivers of Tumor Growth, Metastasis, and Resistance to Therapy. Bioessays 2020; 42:e1900162. [DOI: 10.1002/bies.201900162] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/11/2020] [Indexed: 01/17/2023]
Affiliation(s)
- Barry J. Thompson
- EMBL AustraliaJohn Curtin School of Medical ResearchThe Australian National University 131 Garran Rd, Acton 2602 Canberra ACT Australia
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Role of Epidermal Growth Factor Receptor (EGFR) and Its Ligands in Kidney Inflammation and Damage. Mediators Inflamm 2018; 2018:8739473. [PMID: 30670929 PMCID: PMC6323488 DOI: 10.1155/2018/8739473] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/29/2018] [Accepted: 11/07/2018] [Indexed: 12/29/2022] Open
Abstract
Chronic kidney disease (CKD) is characterized by persistent inflammation and progressive fibrosis, ultimately leading to end-stage renal disease. Although many studies have investigated the factors involved in the progressive deterioration of renal function, current therapeutic strategies only delay disease progression, leaving an unmet need for effective therapeutic interventions that target the cause behind the inflammatory process and could slow down or reverse the development and progression of CKD. Epidermal growth factor receptor (EGFR) (ERBB1), a membrane tyrosine kinase receptor expressed in the kidney, is activated after renal damage, and preclinical studies have evidenced its potential as a therapeutic target in CKD therapy. To date, seven official EGFR ligands have been described, including epidermal growth factor (EGF) (canonical ligand), transforming growth factor-α, heparin-binding epidermal growth factor, amphiregulin, betacellulin, epiregulin, and epigen. Recently, the connective tissue growth factor (CTGF/CCN2) has been described as a novel EGFR ligand. The direct activation of EGFR by its ligands can exert different cellular responses, depending on the specific ligand, tissue, and pathological condition. Among all EGFR ligands, CTGF/CCN2 is of special relevance in CKD. This growth factor, by binding to EGFR and downstream signaling pathway activation, regulates renal inflammation, cell growth, and fibrosis. EGFR can also be “transactivated” by extracellular stimuli, including several key factors involved in renal disease, such as angiotensin II, transforming growth factor beta (TGFB), and other cytokines, including members of the tumor necrosis factor superfamily, showing another important mechanism involved in renal pathology. The aim of this review is to summarize the contribution of EGFR pathway activation in experimental kidney damage, with special attention to the regulation of the inflammatory response and the role of some EGFR ligands in this process. Better insights in EGFR signaling in renal disease could improve our current knowledge of renal pathology contributing to therapeutic strategies for CKD development and progression.
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Singh B, Modica-Napolitano JS, Singh KK. Defining the momiome: Promiscuous information transfer by mobile mitochondria and the mitochondrial genome. Semin Cancer Biol 2017; 47:1-17. [PMID: 28502611 PMCID: PMC5681893 DOI: 10.1016/j.semcancer.2017.05.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/20/2017] [Accepted: 05/07/2017] [Indexed: 12/30/2022]
Abstract
Mitochondria are complex intracellular organelles that have long been identified as the powerhouses of eukaryotic cells because of the central role they play in oxidative metabolism. A resurgence of interest in the study of mitochondria during the past decade has revealed that mitochondria also play key roles in cell signaling, proliferation, cell metabolism and cell death, and that genetic and/or metabolic alterations in mitochondria contribute to a number of diseases, including cancer. Mitochondria have been identified as signaling organelles, capable of mediating bidirectional intracellular information transfer: anterograde (from nucleus to mitochondria) and retrograde (from mitochondria to nucleus). More recently, evidence is now building that the role of mitochondria extends to intercellular communication as well, and that the mitochondrial genome (mtDNA) and even whole mitochondria are indeed mobile and can mediate information transfer between cells. We define this promiscuous information transfer function of mitochondria and mtDNA as "momiome" to include all mobile functions of mitochondria and the mitochondrial genome. Herein, we review the "momiome" and explore its role in cancer development, progression, and treatment.
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Affiliation(s)
- Bhupendra Singh
- Department of Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Keshav K Singh
- Department of Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Environmental Health, Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA; Center for Aging, University of Alabama at Birmingham, Birmingham, AL, USA; UAB Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA; Birmingham Veterans Affairs Medical Center, Birmingham, AL, USA.
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P2Y 2 receptor modulates shear stress-induced cell alignment and actin stress fibers in human umbilical vein endothelial cells. Cell Mol Life Sci 2016; 74:731-746. [PMID: 27652381 PMCID: PMC5272905 DOI: 10.1007/s00018-016-2365-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/28/2016] [Accepted: 09/12/2016] [Indexed: 10/25/2022]
Abstract
Endothelial cells release ATP in response to fluid shear stress, which activates purinergic (P2) receptor-mediated signaling molecules including endothelial nitric oxide (eNOS), a regulator of vascular tone. While P2 receptor-mediated signaling in the vasculature is well studied, the role of P2Y2 receptors in shear stress-associated endothelial cell alignment, cytoskeletal alterations, and wound repair remains ill defined. To address these aspects, human umbilical vein endothelial cell (HUVEC) monolayers were cultured on gelatin-coated dishes and subjected to a shear stress of 1 Pa. HUVECs exposed to either P2Y2 receptor antagonists or siRNA showed impaired fluid shear stress-induced cell alignment, and actin stress fiber formation as early as 6 h. Similarly, when compared to cells expressing the P2Y2 Arg-Gly-Asp (RGD) wild-type receptors, HUVECs transiently expressing the P2Y2 Arg-Gly-Glu (RGE) mutant receptors showed reduced cell alignment and actin stress fiber formation in response to shear stress as well as to P2Y2 receptor agonists in static cultures. Additionally, we observed reduced shear stress-induced phosphorylation of focal adhesion kinase (Y397), and cofilin-1 (S3) with receptor knockdown as well as in cells expressing the P2Y2 RGE mutant receptors. Consistent with the role of P2Y2 receptors in vasodilation, receptor knockdown and overexpression of P2Y2 RGE mutant receptors reduced shear stress-induced phosphorylation of AKT (S473), and eNOS (S1177). Furthermore, in a scratched wound assay, shear stress-induced cell migration was reduced by both pharmacological inhibition and receptor knockdown. Together, our results suggest a novel role for P2Y2 receptor in shear stress-induced cytoskeletal alterations in HUVECs.
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11
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Dissmore T, Seye CI, Medeiros DM, Weisman GA, Bradford B, Mamedova L. The P2Y2 receptor mediates uptake of matrix-retained and aggregated low density lipoprotein in primary vascular smooth muscle cells. Atherosclerosis 2016; 252:128-135. [PMID: 27522265 PMCID: PMC5060008 DOI: 10.1016/j.atherosclerosis.2016.07.927] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/25/2016] [Accepted: 07/27/2016] [Indexed: 01/29/2023]
Abstract
BACKGROUND AND AIMS The internalization of aggregated low-density lipoproteins (agLDL) mediated by low-density lipoprotein receptor related protein (LRP1) may involve the actin cytoskeleton in ways that differ from the endocytosis of soluble LDL by the LDL receptor (LDLR). This study aims to define novel mechanisms of agLDL uptake through modulation of the actin cytoskeleton, to identify molecular targets involved in foam cell formation in vascular smooth muscle cells (VSMCs). The critical observation that formed the basis for these studies is that under pathophysiological conditions, nucleotide release from blood-derived and vascular cells activates SMC P2Y2 receptors (P2Y2Rs) leading to rearrangement of the actin cytoskeleton and cell motility. Therefore, we tested the hypothesis that P2Y2R activation mediates agLDL uptake by VSMCs. METHODS Primary VSMCs were isolated from aortas of wild type (WT) C57BL/6 and.P2Y2R-/- mice to investigate whether P2Y2R activation modulates LRP1 expression. Cells were transiently transfected with cDNA encoding a hemagglutinin-tagged (HA-tagged) WT P2Y2R, or a mutant P2Y2R that unlike the WT P2Y2R does not bind the cytoskeletal actin-binding protein filamin-A (FLN-A). RESULTS P2Y2R activation significantly increased agLDL uptake, and LRP1 mRNA expression decreased in P2Y2R-/- VSMCs versus WT. SMCs, expressing P2Y2R defective in FLN-A binding, exhibit 3-fold lower LDLR expression levels than SMCs expressing WT P2Y2R, while cells transfected with WT P2Y2R show greater agLDL uptake in both WT and P2Y2R-/- VSMCs versus cells transfected with the mutant P2Y2R. CONCLUSIONS Together, these results show that both LRP1 and LDLR expression and agLDL uptake are regulated by P2Y2R in VSMCs, and that agLDL uptake due to P2Y2R activation is dependent upon cytoskeletal reorganization mediated by P2Y2R binding to FLN-A.
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Affiliation(s)
| | - Cheikh I Seye
- Indiana University School of Medicine, Indianapolis, IN, United States
| | - Denis M Medeiros
- School of Graduate Studies, University of Missouri, Kansas City, MO, United States
| | - Gary A Weisman
- Department of Biochemistry and Bond Life Sciences Center, University of Missouri, Columbia, United States
| | - Barry Bradford
- Animal Sciences and Industry, Kansas State University, Manhattan, KS, United States
| | - Laman Mamedova
- Animal Sciences and Industry, Kansas State University, Manhattan, KS, United States.
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12
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P2Y2R activation by nucleotides released from the highly metastatic breast cancer cell MDA-MB-231 contributes to pre-metastatic niche formation by mediating lysyl oxidase secretion, collagen crosslinking, and monocyte recruitment. Oncotarget 2015; 5:9322-34. [PMID: 25238333 PMCID: PMC4253437 DOI: 10.18632/oncotarget.2427] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Tumor microenvironmental hypoxia induces hypoxia inducible factor-1α (HIF-1α) overexpression, leading to the release of lysyl oxidase (LOX), which crosslinks collagen at distant sites to facilitate environmental changes that allow cancer cells to easily metastasize. Our previous study showed that activation of the P2Y2 receptor (P2Y2R) by ATP released from MDA-MB-231 cells increased MDA-MB-231 cell invasion through endothelial cells. Therefore, in this study, we investigated the role of P2Y2R in breast cancer cell metastasis to distant sites. ATP or UTP released from hypoxia-treated MDA-MB-231 cells induced HIF-1α expression and LOX secretion by the activation of P2Y2R, and this phenomenon was significantly reduced in P2Y2R-depleted MDA-MB-231 cells. Furthermore, P2Y2R-mediated LOX release induced collagen crosslinking in an in vitro model. Finally, nude mice injected with MDA-MB-231 cells showed high levels of LOX secretion, crosslinked collagen and CD11b+ BMDC recruitment in the lung; however, mice that were injected with P2Y2R-depleted MDA-MB-231 cells did not exhibit these changes. These results demonstrate that P2Y2R plays an important role in activation of the HIF-1α-LOX axis, the induction of collagen crosslinking and the recruitment of CD11b+ BMDCs. Furthermore, P2Y2R activation by nucleotides recruits THP-1 monocytes, resulting in primary tumor progression and pre-metastatic niche formation.
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Burnstock G, Di Virgilio F. Purinergic signalling and cancer. Purinergic Signal 2014; 9:491-540. [PMID: 23797685 DOI: 10.1007/s11302-013-9372-5] [Citation(s) in RCA: 234] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Accepted: 06/06/2013] [Indexed: 01/24/2023] Open
Abstract
Receptors for extracellular nucleotides are widely expressed by mammalian cells. They mediate a large array of responses ranging from growth stimulation to apoptosis, from chemotaxis to cell differentiation and from nociception to cytokine release, as well as neurotransmission. Pharma industry is involved in the development and clinical testing of drugs selectively targeting the different P1 nucleoside and P2 nucleotide receptor subtypes. As described in detail in the present review, P2 receptors are expressed by all tumours, in some cases to a very high level. Activation or inhibition of selected P2 receptor subtypes brings about cancer cell death or growth inhibition. The field has been largely neglected by current research in oncology, yet the evidence presented in this review, most of which is based on in vitro studies, although with a limited amount from in vivo experiments and human studies, warrants further efforts to explore the therapeutic potential of purinoceptor targeting in cancer.
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Rotfeld H, Hillman P, Ickowicz D, Breitbart H. PKA and CaMKII mediate PI3K activation in bovine sperm by inhibition of the PKC/PP1 cascade. Reproduction 2014; 147:347-56. [DOI: 10.1530/rep-13-0560] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To enable fertilization, spermatozoa must undergo several biochemical processes in the female reproductive tract, collectively called capacitation. These processes involve protein kinase A (PKA)-dependent protein tyrosine phosphorylation including phosphatidylinositol-3-kinase (PI3K). It is not known how PKA, a serine/threonine (S/T) kinase, mediates tyrosine phosphorylation of proteins. We recently showed that inhibition of S/T phosphatase 1 (PP1) causes a significant increase in phospho-PI3K. In this study, we propose a mechanism by which PKA and PP1 mediate an increase in PI3K tyrosine phosphorylation and implicate calmodulin-dependent kinase II (CaMKII) in this process. Inhibition of sperm PP1 or PKC, stimulated CaMKII phosphorylation/activation, and inhibition of PKC enhanced PP1 phosphorylation/inactivation. Inhibition of CaMKII, using KN-93, caused significant reduction in phospho-PP1, indicating its activation. Moreover, KN-93 prevented the dephosphorylation/inactivation of PKC. We therefore suggest that CaMKII inhibits PKC, leading to PP1 inhibition and the reciprocal auto-activation of CaMKII. Thus, CaMKII can regulate its own activation by inhibiting the PKC/PP1 cascade. Inhibition of Src family kinases (SFK) caused significant inhibition of CaMKII and PP1 phosphorylation, suggesting that SFK activity results in PP1 inhibition and CaMKII activation. Activation of sperm PKA by 8Br-cAMP revealed an increase in phospho-CaMKII, which was inhibited by PKA inhibitor. Tyrosine phosphorylation of PI3K was stimulated by 8Br-cAMP and by PKC or PP1 inhibition and was abrogated by CaMKII inhibition. Furthermore, phosphorylation/activation of the tyrosine kinase Pyk2 was enhanced by PP1 inhibition, and this activation is blocked by CaMKII inhibition. Thus, PKA activates Src, which inhibits PP1, leading to CaMKII and Pyk2 activation, resulting in PI3K tyrosine phosphorylation/activation.
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Non-canonical signalling and roles of the vasoactive peptides angiotensins and kinins. Clin Sci (Lond) 2014; 126:753-74. [DOI: 10.1042/cs20130414] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
GPCRs (G-protein-coupled receptors) are among the most important targets for drug discovery due to their ubiquitous expression and participation in cellular events under both healthy and disease conditions. These receptors can be activated by a plethora of ligands, such as ions, odorants, small ligands and peptides, including angiotensins and kinins, which are vasoactive peptides that are classically involved in the pathophysiology of cardiovascular events. These peptides and their corresponding GPCRs have been reported to play roles in other systems and under pathophysiological conditions, such as cancer, central nervous system disorders, metabolic dysfunction and bone resorption. More recently, new mechanisms have been described for the functional regulation of GPCRs, including the transactivation of other signal transduction receptors and the activation of G-protein-independent pathways. The existence of such alternative mechanisms for signal transduction and the discovery of agonists that can preferentially trigger one signalling pathway over other pathways (called biased agonists) have opened new perspectives for the discovery and development of drugs with a higher specificity of action and, therefore, fewer side effects. The present review summarizes the current knowledge on the non-canonical signalling and roles of angiotensins and kinins.
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Soltoff SP, Lannon WA. Activation of ERK1/2 by store-operated calcium entry in rat parotid acinar cells. PLoS One 2013; 8:e72881. [PMID: 24009711 PMCID: PMC3756958 DOI: 10.1371/journal.pone.0072881] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 07/15/2013] [Indexed: 12/23/2022] Open
Abstract
The regulation of intracellular Ca2+ concentration ([Ca2+]i) plays a critical role in a variety of cellular processes, including transcription, protein activation, vesicle trafficking, and ion movement across epithelial cells. In many cells, the activation of phospholipase C-coupled receptors hydrolyzes membrane phosphoinositides and produces the depletion of endoplasmic reticulum Ca2+ stores, followed by the sustained elevation of [Ca2+]i from Ca2+ entry across the plasma membrane via store-operated Ca2+ entry (SOCE). Ca2+ entry is also increased in a store-independent manner by arachidonate-regulated Ca2+ (ARC) channels. Using rat parotid salivary gland cells, we examined multiple pathways of Ca2+ entry/elevation to determine if they activated cell signaling proteins and whether this occurred in a pathway-dependent manner. We observed that SOCE activates extracellular signal-related kinases 1 and 2 (ERK1/2) to ∼3-times basal levels via a receptor-independent mechanism when SOCE was initiated by depleting Ca2+ stores using the endoplasmic reticulum Ca2+-ATPase inhibitor thapsigargin (TG). TG-initiated ERK1/2 phosphorylation increased as rapidly as that initiated by the muscarinic receptor agonist carbachol, which promoted an increase to ∼5-times basal levels. Notably, ERK1/2 phosphorylation was not increased by the global elevation of [Ca2+]i by Ca2+ ionophore or by Ca2+ entry via ARC channels in native cells, although ERK1/2 phosphorylation was increased by Ca2+ ionophore in Par-C10 and HSY salivary cell lines. Agents and conditions that blocked SOCE in native cells, including 2-aminoethyldiphenyl borate (2-APB), SKF96363, and removal of extracellular Ca2+, also reduced TG- and carbachol-stimulated ERK1/2 phosphorylation. TG-promoted ERK1/2 phosphorylation was blocked when SRC and Protein Kinases C (PKC) were inhibited, and it was blocked in cells pretreated with β-adrenergic agonist isoproterenol. These observations demonstrate that ERK1/2 is activated by a selective mechanism of Ca2+ entry (SOCE) in these cells, and suggest that ERK1/2 may contribute to events downstream of SOCE.
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Affiliation(s)
- Stephen P Soltoff
- Beth Israel Deaconess Medical Center, Department of Medicine, Division of Signal Transduction, Harvard Medical School, Boston, Massachussetts, USA.
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Li WH, Qiu Y, Zhang HQ, Liu Y, You JF, Tian XX, Fang WG. P2Y2 receptor promotes cell invasion and metastasis in prostate cancer cells. Br J Cancer 2013; 109:1666-75. [PMID: 23969730 PMCID: PMC3776994 DOI: 10.1038/bjc.2013.484] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/11/2013] [Accepted: 07/26/2013] [Indexed: 01/03/2023] Open
Abstract
Background: Our previous study demonstrated that extracellular adenosine 5′-triphosphate (ATP) stimulated prostate cancer cell invasion via P2Y receptors. However, the purinergic receptor subtype(s) involved in this process remains unclear. Here we aimed to determine whether P2Y2, one subtype of P2Y receptors, was involved in the invasion and metastasis of prostate cancer cells, and elucidated the underlying mechanism. Methods: RNAi was introduced to silence the expression of P2Y2. In vitro invasion and migration assays and in vivo experiments were carried out to examine the role of P2Y2 receptor in cell invasion and metastasis. cDNA microarray was performed to identify the differentially expressed genes downstream of ATP treatment. Results: P2Y2 was significantly expressed in the prostate cancer cells. Knockdown of P2Y2 receptor suppressed cell invasion and metastasis in vitro and in vivo. Further experiments identified that ATP could promote IL-8 and Snail expression and inhibit E-cadherin and Claudin-1 expression. Knockdown of P2Y2 receptor affected the expression of these EMT/invasion-related genes in vitro and in vivo. Conclusion: P2Y2 receptor promotes cell invasion and metastasis in prostate cancer cells via some EMT/invasion-related genes. Thereby, P2Y2 receptor could be a potential therapeutic target for the treatment of prostate cancer.
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Affiliation(s)
- W-H Li
- 1] Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Peking University Health Science Center, Beijing 100191, China [2] Department of Pathology, Peking University Health Science Center, Beijing 100191, China
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Weisman GA, Woods LT, Erb L, Seye CI. P2Y receptors in the mammalian nervous system: pharmacology, ligands and therapeutic potential. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2013; 11:722-38. [PMID: 22963441 DOI: 10.2174/187152712803581047] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 06/14/2012] [Accepted: 06/14/2012] [Indexed: 11/22/2022]
Abstract
P2Y receptors for extracellular nucleotides are coupled to activation of a variety of G proteins and stimulate diverse intracellular signaling pathways that regulate functions of cell types that comprise the central nervous system (CNS). There are 8 different subtypes of P2Y receptor expressed in cells of the CNS that are activated by a select group of nucleotide agonists. Here, the agonist selectivity of these 8 P2Y receptor subtypes is reviewed with an emphasis on synthetic agonists with high potency and resistance to degradation by extracellular nucleotidases that have potential applications as therapeutic agents. In addition, the recent identification of a wide variety of subtype-selective antagonists is discussed, since these compounds are critical for discerning cellular responses mediated by activation of individual P2Y receptor subtypes. The functional expression of P2Y receptor subtypes in cells that comprise the CNS is also reviewed and the role of each subtype in the regulation of physiological and pathophysiological responses is considered. Other topics include the role of P2Y receptors in the regulation of blood-brain barrier integrity and potential interactions between different P2Y receptor subtypes that likely impact tissue responses to extracellular nucleotides in the CNS. Overall, current research suggests that P2Y receptors in the CNS regulate repair mechanisms that are triggered by tissue damage, inflammation and disease and thus P2Y receptors represent promising targets for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Gary A Weisman
- Department of Biochemistry, 540E Life Sciences Center, 1201 Rollins Road, University of Missouri, Columbia, MO 65211-7310, USA.
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Faure E, Garrouste F, Parat F, Monferran S, Leloup L, Pommier G, Kovacic H, Lehmann M. P2Y2 receptor inhibits EGF-induced MAPK pathway to stabilise keratinocyte hemidesmosomes. J Cell Sci 2012; 125:4264-77. [PMID: 22718344 DOI: 10.1242/jcs.097600] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
α6β4 integrin is the main component of hemidesmosomes (HD) that stably anchor the epithelium to the underlying basement membrane. Epithelial cell migration requires HD remodelling, which can be promoted by epidermal growth factor (EGF). We previously showed that extracellular nucleotides inhibit growth factor-induced keratinocyte migration. Here, we investigate the effect of extracellular nucleotides on α6β4 integrin localisation in HD during EGF-induced cell migration. Using a combination of pharmacological inhibition and gene silencing approaches, we found that UTP activates the P2Y2 purinergic receptor and Gαq protein to inhibit EGF/ERK1/2-induced cell migration in keratinocytes. Using a keratinocyte cell line expressing an inducible form of the Raf kinase, we show that UTP inhibits the EGF-induced ERK1/2 pathway activation downstream of Raf. Moreover, we established that ERK1/2 activation by EGF leads to the mobilisation of α6β4 integrin from HD. Importantly, activation of P2Y2R and Gαq by UTP promotes HD formation and protects these structures from EGF-triggered dissolution as revealed by confocal analysis of the distribution of α6β4 integrin, plectin, BPAG1, BPAG2 and CD151 in keratinocytes. Finally, we demonstrated that the activation of p90RSK, downstream of ERK1/2, is sufficient to promote EGF-mediated HD dismantling and that UTP does not stabilise HD in cells expressing an activated form of p90RSK. Our data underline an unexpected role of P2Y2R and Gαq in the inhibition of the ERK1/2 signalling pathway and in the modulation of hemidesmosome dynamics and keratinocyte migration.
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Affiliation(s)
- Emilie Faure
- Aix-Marseille Université, INSERM UMR 911, Centre de Recherche en Oncologie Biologique et en Oncopharmacologie, Marseille 13005, France
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Weisman GA, Ajit D, Garrad R, Peterson TS, Woods LT, Thebeau C, Camden JM, Erb L. Neuroprotective roles of the P2Y(2) receptor. Purinergic Signal 2012; 8:559-78. [PMID: 22528682 DOI: 10.1007/s11302-012-9307-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 10/04/2011] [Indexed: 02/07/2023] Open
Abstract
Purinergic signaling plays a unique role in the brain by integrating neuronal and glial cellular circuits. The metabotropic P1 adenosine receptors and P2Y nucleotide receptors and ionotropic P2X receptors control numerous physiological functions of neuronal and glial cells and have been implicated in a wide variety of neuropathologies. Emerging research suggests that purinergic receptor interactions between cells of the central nervous system (CNS) have relevance in the prevention and attenuation of neurodegenerative diseases resulting from chronic inflammation. CNS responses to chronic inflammation are largely dependent on interactions between different cell types (i.e., neurons and glia) and activation of signaling molecules including P2X and P2Y receptors. Whereas numerous P2 receptors contribute to functions of the CNS, the P2Y(2) receptor is believed to play an important role in neuroprotection under inflammatory conditions. While acute inflammation is necessary for tissue repair due to injury, chronic inflammation contributes to neurodegeneration in Alzheimer's disease and occurs when glial cells undergo prolonged activation resulting in extended release of proinflammatory cytokines and nucleotides. This review describes cell-specific and tissue-integrated functions of P2 receptors in the CNS with an emphasis on P2Y(2) receptor signaling pathways in neurons, glia, and endothelium and their role in neuroprotection.
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Affiliation(s)
- Gary A Weisman
- Department of Biochemistry, University of Missouri, 540E Life Sciences Center, 1201 Rollins Road, Columbia, MO 65211-7310, USA.
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Weisman GA, Camden JM, Peterson TS, Ajit D, Woods LT, Erb L. P2 receptors for extracellular nucleotides in the central nervous system: role of P2X7 and P2Y₂ receptor interactions in neuroinflammation. Mol Neurobiol 2012; 46:96-113. [PMID: 22467178 DOI: 10.1007/s12035-012-8263-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 03/21/2012] [Indexed: 12/16/2022]
Abstract
Extracellular nucleotides induce cellular responses in the central nervous system (CNS) through the activation of ionotropic P2X and metabotropic P2Y nucleotide receptors. Activation of these receptors regulates a wide range of physiological and pathological processes. In this review, we present an overview of the current literature regarding P2X and P2Y receptors in the CNS with a focus on the contribution of P2X7 and P2Y(2) receptor-mediated responses to neuroinflammatory and neuroprotective mechanisms.
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Affiliation(s)
- Gary A Weisman
- Department of Biochemistry, University of Missouri, 540E Life Sciences Center, 1201 Rollins Road, Columbia, MO 65211-7310, USA.
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Interaction of purinergic receptors with GPCRs, ion channels, tyrosine kinase and steroid hormone receptors orchestrates cell function. Purinergic Signal 2011; 8:91-103. [PMID: 21887492 DOI: 10.1007/s11302-011-9260-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 08/16/2011] [Indexed: 01/26/2023] Open
Abstract
Extracellular purines and pyrimidines have emerged as key regulators of a wide range of physiological and pathophysiological cellular processes acting through P1 and P2 cell surface receptors. Increasing evidence suggests that purinergic receptors can interact with and/or modulate the activity of other classes of receptors and ion channels. This review will focus on the interactions of purinergic receptors with other GPCRs, ion channels, receptor tyrosine kinases, and steroid hormone receptors. Also, the signal transduction pathways regulated by these complexes and their new functional properties are discussed.
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Ding L, Ma W, Littmann T, Camp R, Shen J. The P2Y(2) nucleotide receptor mediates tissue factor expression in human coronary artery endothelial cells. J Biol Chem 2011; 286:27027-38. [PMID: 21652710 DOI: 10.1074/jbc.m111.235176] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The discovery of the role of P2Y(12) receptor in platelet aggregation leads to a new anti-thrombotic drug Plavix; however, little is known about non-platelet P2Y receptors in thrombosis. This study tested the hypothesis that endothelial P2Y receptor(s) mediates up-regulation of tissue factor (TF), the initiator of coagulation cascade. Stimulation of human coronary artery endothelial cells (HCAEC) by UTP/ATP increased the mRNA level of TF but not of its counterpart-tissue factor pathway inhibitor, which was accompanied by up-regulation of TF protein and cell surface activity. RT-PCR revealed a selective expression of P2Y(2) and P2Y(11) receptors in HCAEC. Consistent with this, TF up-regulation was inhibited by suramin or by siRNA silencing of P2Y(2) receptor, but not by NF-157, a P2Y(11)-selective antagonist, suggesting a role for the P2Y(2) receptor. In addition, P2Y(2) receptor activated ERK1/2, JNK, and p38 MAPK pathways without affecting the positive NF-κB and negative AKT regulatory pathways of TF expression. Furthermore, TF up-regulation was abolished or partially suppressed by inhibition of p38 or JNK but not ERK1/2. Interestingly, blockade of the PLC/Ca(2+) pathway did not affect P2Y(2) receptor activation of p38, JNK, and TF induction. However, blockade of Src kinase reduced phosphorylation of p38 but not JNK, eliminating TF induction. In contrast, inhibition of Rho kinase reduced phosphorylation of JNK but not p38, decreasing TF expression. These findings demonstrate that P2Y(2) receptor mediates TF expression in HCAEC through new mechanisms involving Src/p38 and Rho/JNK pathways, possibly contributing to a pro-thrombotic status after vascular injury.
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Affiliation(s)
- Ling Ding
- Division of Pharmacology, Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, Alabama 36849, USA
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The metabotropic glutamate receptor activates the lipid kinase PI3K in Drosophila motor neurons through the calcium/calmodulin-dependent protein kinase II and the nonreceptor tyrosine protein kinase DFak. Genetics 2011; 188:601-13. [PMID: 21515581 DOI: 10.1534/genetics.111.128561] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Ligand activation of the metabotropic glutamate receptor (mGluR) activates the lipid kinase PI3K in both the mammalian central nervous system and Drosophila motor nerve terminal. In several subregions of the mammalian brain, mGluR-mediated PI3K activation is essential for a form of synaptic plasticity termed long-term depression (LTD), which is implicated in neurological diseases such as fragile X and autism. In Drosophila larval motor neurons, ligand activation of DmGluRA, the sole Drosophila mGluR, similarly mediates a PI3K-dependent downregulation of neuronal activity. The mechanism by which mGluR activates PI3K remains incompletely understood in either mammals or Drosophila. Here we identify CaMKII and the nonreceptor tyrosine kinase DFak as critical intermediates in the DmGluRA-dependent activation of PI3K at Drosophila motor nerve terminals. We find that transgene-induced CaMKII inhibition or the DFak(CG1) null mutation each block the ability of glutamate application to activate PI3K in larval motor nerve terminals, whereas transgene-induced CaMKII activation increases PI3K activity in motor nerve terminals in a DFak-dependent manner, even in the absence of glutamate application. We also find that CaMKII activation induces other PI3K-dependent effects, such as increased motor axon diameter and increased synapse number at the larval neuromuscular junction. CaMKII, but not PI3K, requires DFak activity for these increases. We conclude that the activation of PI3K by DmGluRA is mediated by CaMKII and DFak.
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Hedden L, Benes CH, Soltoff SP. P2X(7) receptor antagonists display agonist-like effects on cell signaling proteins. Biochim Biophys Acta Gen Subj 2011; 1810:532-42. [PMID: 21397667 DOI: 10.1016/j.bbagen.2011.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/14/2011] [Accepted: 03/07/2011] [Indexed: 11/17/2022]
Abstract
BACKGROUND The activation of various P2 receptors (P2R) by extracellular nucleotides promotes diverse cellular events, including the stimulation of cell signaling protein and increases in [Ca(2+)](i). We report that some agents that can block P2X(7)R receptors also promote diverse P2X(7)R-independent effects on cell signaling. METHODS We exposed native rat parotid acinar cells, salivary gland cell lines (Par-C10, HSY, HSG), and PC12 cells to suramin, DIDS (4,4'-diisothiocyano stilbene-2,2'-disulfonic acid), Cibacron Blue 3GA, Brilliant Blue G, and the P2X(7)R-selective antagonist A438079, and examined the activation/phosphorylation of ERK1/2, PKCδ, Src, CDCP1, and other signaling proteins. RESULTS With the exception of suramin, these agents blocked the phosphorylation of ERK1/2 by BzATP in rat parotid acinar cells; but higher concentrations of suramin blocked ATP-stimulated (45)Ca(2+) entry. Aside from A438079, these agents increased the phosphorylation of ERK1/2, Src, PKCδ, and other proteins (including Dok-1) within minutes in an agent- and cell type-specific manner in the absence of a P2X(7)R ligand. The stimulatory effect of these compounds on the tyrosine phosphorylation of CDCP1 and its Src-dependent association with PKCδ was blocked by knockdown of CDCP1, which also blocked Src and PKCδ phosphorylation. CONCLUSIONS Several agents used as P2X(7)R blockers promote the activation of various signaling proteins and thereby act more like receptor agonists than antagonists. GENERAL SIGNIFICANCE Some compounds used to block P2 receptors have complicated effects that may confound their use in blocking receptor activation and other biological processes for which they are employed, including their use as blockers of various ion transport proteins.
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Affiliation(s)
- Lee Hedden
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Lee KL, Dai Q, Hansen EL, Saner CN, Price TM. Modulation of ATP-induced calcium signaling by progesterone in T47D-Y breast cancer cells. Mol Cell Endocrinol 2010; 319:109-15. [PMID: 20079401 PMCID: PMC2837125 DOI: 10.1016/j.mce.2010.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 01/06/2010] [Accepted: 01/06/2010] [Indexed: 11/28/2022]
Abstract
Extracellular ATP activates purinergic (P(2)) receptors with an increase in intracellular calcium and phosphorylation of MAPK. In this study we have investigated the effect of progesterone/progestin on ATP-induced calcium mobilization and phosphorylation of the kinase ERK in the T47D-Y breast cancer cell line that exhibits no detectable nuclear progesterone receptor expression. Brief pretreatment with progesterone/progestin results in a dose dependent inhibition of ATP-induced intracellular calcium mobilization, and inhibition of ERK phosphorylation. Response to a cell impermeable ligand and inhibition of the response by an inactivating antibody suggests a mechanism of action at the plasma membrane. These results in T47D-Y cells strongly suggest that progesterone can act in a rapid non-nuclear manner to inhibit extracellular ATP effects on intracellular calcium mobilization and ERK activation. This research provides an example of progesterone action in a breast cancer cell line lacking expression of the classical nuclear progesterone receptors.
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Affiliation(s)
| | | | | | | | - Thomas M Price
- Corresponding author: Thomas M. Price, MD, Box 3928, DUMC, Durham, NC 27710, Tel: 919 681-3579, Fax: 919 484-0461,
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Peterson TS, Camden JM, Wang Y, Seye CI, Wood WG, Sun GY, Erb L, Petris MJ, Weisman GA. P2Y2 nucleotide receptor-mediated responses in brain cells. Mol Neurobiol 2010; 41:356-66. [PMID: 20387013 DOI: 10.1007/s12035-010-8115-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 03/01/2010] [Indexed: 01/14/2023]
Abstract
Acute inflammation is important for tissue repair; however, chronic inflammation contributes to neurodegeneration in Alzheimer's disease (AD) and occurs when glial cells undergo prolonged activation. In the brain, stress or damage causes the release of nucleotides and activation of the G(q) protein-coupled P2Y(2) nucleotide receptor subtype (P2Y(2)R) leading to pro-inflammatory responses that can protect neurons from injury, including the stimulation and recruitment of glial cells. P2Y(2)R activation induces the phosphorylation of the epidermal growth factor receptor (EGFR), a response dependent upon the presence of a SH3 binding domain in the intracellular C terminus of the P2Y(2)R that promotes Src binding and transactivation of EGFR, a pathway that regulates the proliferation of cortical astrocytes. Other studies indicate that P2Y(2)R activation increases astrocyte migration. P2Y(2)R activation by UTP increases the expression in astrocytes of alpha(V)beta(3/5) integrins that bind directly to the P2Y(2)R via an Arg-Gly-Asp (RGD) motif in the first extracellular loop of the P2Y(2)R, an interaction required for G(o) and G(12) protein-dependent astrocyte migration. In rat primary cortical neurons (rPCNs) P2Y(2)R expression is increased by stimulation with interleukin-1beta (IL-1beta), a pro-inflammatory cytokine whose levels are elevated in AD, in part due to nucleotide-stimulated release from glial cells. Other results indicate that oligomeric beta-amyloid peptide (Abeta(1-42)), a contributor to AD, increases nucleotide release from astrocytes, which would serve to activate upregulated P2Y(2)Rs in neurons. Data with rPCNs suggest that P2Y(2)R upregulation by IL-1beta and subsequent activation by UTP are neuroprotective, since this increases the non-amyloidogenic cleavage of amyloid precursor protein. Furthermore, activation of IL-1beta-upregulated P2Y(2)Rs in rPCNs increases the phosphorylation of cofilin, a cytoskeletal protein that stabilizes neurite outgrowths. Thus, activation of pro-inflammatory P2Y(2)Rs in glial cells can promote neuroprotective responses, suggesting that P2Y(2)Rs represent a novel pharmacological target in neurodegenerative and other pro-inflammatory diseases.
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Affiliation(s)
- Troy S Peterson
- Department of Biochemistry, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
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Myers TJ, Brennaman LH, Stevenson M, Higashiyama S, Russell WE, Lee DC, Sunnarborg SW. Mitochondrial reactive oxygen species mediate GPCR-induced TACE/ADAM17-dependent transforming growth factor-alpha shedding. Mol Biol Cell 2010; 20:5236-49. [PMID: 19846666 DOI: 10.1091/mbc.e08-12-1256] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Epidermal growth factor receptor (EGFR) activation by GPCRs regulates many important biological processes. ADAM metalloprotease activity has been implicated as a key step in transactivation, yet the regulatory mechanisms are not fully understood. Here, we investigate the regulation of transforming growth factor-alpha (TGF-alpha) shedding by reactive oxygen species (ROS) through the ATP-dependent activation of the P2Y family of GPCRs. We report that ATP stimulates TGF-alpha proteolysis with concomitant EGFR activation and that this process requires TACE/ADAM17 activity in both murine fibroblasts and CHO cells. ATP-induced TGF-alpha shedding required calcium and was independent of Src family kinases and PKC and MAPK signaling. Moreover, ATP-induced TGF-alpha shedding was completely inhibited by scavengers of ROS, whereas calcium-stimulated shedding was partially inhibited by ROS scavenging. Hydrogen peroxide restored TGF-alpha shedding after calcium chelation. Importantly, we also found that ATP-induced shedding was independent of the cytoplasmic NADPH oxidase complex. Instead, mitochondrial ROS production increased in response to ATP and mitochondrial oxidative complex activity was required to activate TACE-dependent shedding. These results reveal an essential role for mitochondrial ROS in regulating GPCR-induced growth factor shedding.
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Affiliation(s)
- Timothy J Myers
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
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Gill RS, Hsiung MS, Sum CS, Lavine N, Clark SD, Van Tol HH. The dopamine D4 receptor activates intracellular platelet-derived growth factor receptor β to stimulate ERK1/2. Cell Signal 2010; 22:285-90. [DOI: 10.1016/j.cellsig.2009.09.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 09/14/2009] [Indexed: 01/09/2023]
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Ratchford AM, Baker OJ, Camden JM, Rikka S, Petris MJ, Seye CI, Erb L, Weisman GA. P2Y2 nucleotide receptors mediate metalloprotease-dependent phosphorylation of epidermal growth factor receptor and ErbB3 in human salivary gland cells. J Biol Chem 2010; 285:7545-55. [PMID: 20064929 DOI: 10.1074/jbc.m109.078170] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The G protein-coupled receptor P2Y(2) nucleotide receptor (P2Y(2)R) has been shown to be up-regulated in a variety of tissues in response to stress or injury. Recent studies have suggested that P2Y(2)Rs may play a role in immune responses, wound healing, and tissue regeneration via their ability to activate multiple signaling pathways, including activation of growth factor receptors. Here, we demonstrate that in human salivary gland (HSG) cells, activation of the P2Y(2)R by its agonist induces phosphorylation of ERK1/2 via two distinct mechanisms, a rapid, protein kinase C-dependent pathway and a slower and prolonged, epidermal growth factor receptor (EGFR)-dependent pathway. The EGFR-dependent stimulation of UTP-induced ERK1/2 phosphorylation in HSG cells is inhibited by the adamalysin inhibitor tumor necrosis factor-alpha protease inhibitor or by small interfering RNA that selectively silences ADAM10 and ADAM17 expression, suggesting that ADAM metalloproteases are required for P2Y(2)R-mediated activation of the EGFR. G protein-coupled receptors have been shown to promote proteolytic release of EGFR ligands; however, neutralizing antibodies to known ligands of the EGFR did not inhibit UTP-induced EGFR phosphorylation. Immunoprecipitation experiments indicated that UTP causes association of the EGFR with another member of the EGF receptor family, ErbB3. Furthermore, stimulation of HSG cells with UTP induced phosphorylation of ErbB3, and silencing of ErbB3 expression inhibited UTP-induced phosphorylation of both ErbB3 and EGFR. UTP-induced phosphorylation of ErbB3 and EGFR was also inhibited by silencing the expression of the ErbB3 ligand neuregulin 1 (NRG1). These results suggest that P2Y(2)R activation in salivary gland cells promotes the formation of EGFR/ErbB3 heterodimers and metalloprotease-dependent neuregulin 1 release, resulting in the activation of both EGFR and ErbB3.
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Affiliation(s)
- Ann M Ratchford
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211, USA
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Paz-y-Miño C, López-Cortés A, Muñoz MJ, Cabrera A, Castro B, Sánchez ME. Incidence of the L858R and G719S mutations of the epidermal growth factor receptor oncogene in an Ecuadorian population with lung cancer. ACTA ACUST UNITED AC 2010; 196:201-3. [DOI: 10.1016/j.cancergencyto.2009.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Buzzi N, Bilbao PS, Boland R, de Boland AR. Extracellular ATP activates MAP kinase cascades through a P2Y purinergic receptor in the human intestinal Caco-2 cell line. Biochim Biophys Acta Gen Subj 2009; 1790:1651-9. [PMID: 19836435 DOI: 10.1016/j.bbagen.2009.10.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 09/14/2009] [Accepted: 10/08/2009] [Indexed: 11/26/2022]
Abstract
BACKGROUND ATP exerts diverse effects on various cell types via specific purinergic P2Y receptors. Intracellular signaling cascades are the main routes of communication between P2Y receptors and regulatory targets in the cell. METHODS AND RESULTS We examined the role of ATP in the modulation of ERK1/2, JNK1/2, and p38 MAP kinases (MAPKs) in human colon cancer Caco-2 cells. Immunoblot analysis showed that ATP induces the phosphorylation of MAPKs in a time- and dose-dependent manner, peaking at 5 min at 10 microM ATP. Moreover, ATPgammaS, UTP, and UDP but not ADP or ADPbetaS increased phosphorylation of MAPKs, indicating the involvement of, at least, P2Y2/P2Y4 and P2Y6 receptor subtypes. RT-PCR studies and PCR product sequencing supported the expression of P2Y2 and P2Y4 receptors in this cell line. Spectrofluorimetric measurements showed that cell stimulation with ATP induced transient elevations in intracellular calcium concentration. In addition, ATP-induced phosphorylation of MAPKs in Caco-2 cells was dependent on Src family tyrosine kinases, calcium influx, and intracellular Ca2+ release and was partially dependent on the cAMP/PKA and PKC pathways and the EGFR. GENERAL SIGNIFICANCE These findings provide new molecular basis for further understanding the mechanisms involved in ATP functions, as a signal transducer and activator of MAP kinase cascades, in colon adenocarcinoma Caco-2 cells.
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Affiliation(s)
- Natalia Buzzi
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina
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Luke TM, Hexum TD. UTP and ATP increase extracellular signal-regulated kinase 1/2 phosphorylation in bovine chromaffin cells through epidermal growth factor receptor transactivation. Purinergic Signal 2008; 4:323-30. [PMID: 18777108 PMCID: PMC2583213 DOI: 10.1007/s11302-008-9098-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Accepted: 03/14/2008] [Indexed: 01/07/2023] Open
Abstract
Adenosine triphosphate (ATP) is coreleased with catecholamines from adrenal medullary chromaffin cells in response to sympathetic nervous system stimulation and may regulate these cells in an autocrine or paracrine manner. Increases in extracellular signal-regulated kinase (ERK) 1/2 phosphorylation were observed in response to ATP stimulation of bovine chromaffin cells. The signaling pathway involved in ATP-mediated ERK1/2 phosphorylation was investigated via Western blot analysis. ATP and uridine 5′-triphosphate (UTP) increased ERK1/2 phosphorylation potently, peaking between 5 and 15 min. The mitogen-activated protein kinase (MAPK/ERK)-activating kinase (MEK) inhibitor PD98059 blocked this response. UTP, which is selective for G-protein-coupled P2Y receptors, was the most potent agonist among several nucleotides tested. Adenosine 5′-O-(3-thio) triphosphate (ATPγS) and ATP were also potent agonists, characteristic of the P2Y2 or P2Y4 receptor subtypes, whereas agonists selective for P2X receptors or other P2Y receptor subtypes were weakly effective. The receptor involved was further characterized by the nonspecific P2 antagonists suramin and reactive blue 2, which each partially inhibited ATP-mediated ERK1/2 phosphorylation. Inhibitors of protein kinase C (PKC), protein kinase A (PKA), Ca2+/calmodulin-dependent protein kinase II (CaMKII), and phosphoinositide-3 kinase (PI3K) had no effect on ATP-mediated ERK1/2 phosphorylation. The Src inhibitor PP2, epidermal growth factor receptor (EGFR) inhibitor AG1478, and metalloproteinase inhibitor GM6001 decreased ATP-mediated ERK1/2 phosphorylation. These results suggest nucleotide-mediated ERK1/2 phosphorylation is mediated by a P2Y2 or P2Y4 receptor, which stimulates metalloproteinase-dependent transactivation of the EGFR.
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Affiliation(s)
- Toni M. Luke
- University of Nebraska Medical Center, 985800 Nebraska Medical Center, Omaha, NE 68198–5800 USA
| | - Terry D. Hexum
- University of Nebraska Medical Center, 985800 Nebraska Medical Center, Omaha, NE 68198–5800 USA
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Sanabria P, Ross E, Ramirez E, Colon K, Hernandez M, Maldonado HM, Silva WI, Jimenez-Rivera CA, Gonzalez FA. P2Y2 receptor desensitization on single endothelial cells. ACTA ACUST UNITED AC 2008; 15:43-51. [PMID: 18568944 DOI: 10.1080/10623320802092294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Receptor desensitization, or decreased responsiveness of a receptor to agonist stimulation, represents a regulatory process with the potential to have a significant impact on cell behavior. P2Y(2), a G-protein-coupled receptor activated by extracellular nucleotides, undergoes desensitization at many tissues, including the vascular endothelium. Endothelial cells from a variety of vascular beds are normally exposed to extracellular nucleotides released from damaged cells and activated platelets. The purpose of the present study was to compare P2Y(2) receptor desensitization observed in endothelial cells derived from bovine retina, a model of microvascular endothelium, and human umbilical vein endothelial cells (HUVECs), a model of a large blood vessel endothelium. P2Y(2) receptor desensitization was monitored by following changes in UTP-stimulated intracellular free Ca(2 +) in single cells using fura-2 microfluorometry. Both endothelial cell models exhibited desensitization of the P2Y(2) receptor after stimulation with UTP. However, the cells differed in the rate, dependence on agonist concentration, and percentage of maximal desensitization. These results suggest differential mechanisms of P2Y(2) receptor desensitization and favors heterogeneity in extracellular nucleotide activity in endothelial cells according to its vascular bed origin.
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Affiliation(s)
- Priscila Sanabria
- Department of Physiology, Universidad Central del Caribe, Bayamon, Puerto Rico
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Panigone S, Hsieh M, Fu M, Persani L, Conti M. Luteinizing hormone signaling in preovulatory follicles involves early activation of the epidermal growth factor receptor pathway. Mol Endocrinol 2008; 22:924-36. [PMID: 18187604 DOI: 10.1210/me.2007-0246] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
LH activates a cascade of signaling events that are propagated throughout the ovarian preovulatory follicle to promote ovulation of a mature egg. Critical to LH-induced ovulation is the induction of epidermal growth factor (EGF)-like growth factors and transactivation of EGF receptor (EGFR) signaling. Because the timing of this transactivation has not been well characterized, we investigated the dynamics of LH regulation of the EGF network in cultured follicles. Preovulatory follicles were cultured with or without recombinant LH and/or specific inhibitors. EGFR and MAPK phosphorylation were examined by immunoprecipitation and Western blot analyses. By semiquantitative RT-PCR, increases in amphiregulin and epiregulin mRNAs were detected 30 min after recombinant LH stimulation of follicles and were maximal after 2 h. LH-induced EGFR phosphorylation also increased after 30 min and reached a maximum at 2 h. EGFR activation precedes oocyte maturation and is cAMP dependent, because forskolin similarly activated EGFR. LH-induced EGFR phosphorylation was sensitive to AG1478, an EGFR kinase inhibitor, and to inhibitors of matrix metalloproteases GM6001 and TNFalpha protease inhibitor-1 (TAPI-1), suggesting the involvement of EGF-like growth factor shedding. LH- but not amphiregulin-induced oocyte maturation and EGFR phosphorylation were sensitive to protein synthesis inhibition. When granulosa cells were cultured with a combination of neutralizing antibodies against amphiregulin, epiregulin, and betacellulin, EGFR phosphorylation and MAPK activation were inhibited. In cultured follicles, LH-induced MAPK activation was partially inhibited by AG1478 and GM6001, indicating that this pathway is regulated in part by the EGF network but also involves additional pathways. Thus, complex mechanisms are involved in the rapid amplification and propagation of the LH signal within preovulatory follicles and include the early activation of the EGF network.
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Affiliation(s)
- Sara Panigone
- Division of Reproductive Biology, Department of Obstetrics and Gynecology, Stanford, University School of Medicine, Stanford, California 94305, USA
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Heo JS, Lee MY, Han HJ. Sonic hedgehog stimulates mouse embryonic stem cell proliferation by cooperation of Ca2+/protein kinase C and epidermal growth factor receptor as well as Gli1 activation. Stem Cells 2007; 25:3069-80. [PMID: 17901397 DOI: 10.1634/stemcells.2007-0550] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hedgehog signaling has an essential role in the control of stem cell growth in embryonic tissues. Therefore, this study examined the effect of sonic hedgehog (Shh) on the self-renewal of mouse embryonic stem (ES) cells and its related mechanisms. Shh increased DNA synthesis blocked by the inhibition of the smoothened receptor. Shh required Gli1 activation to induce the increases in Notch/Hes-1 and Wnt/beta-catenin. Shh increased the intracellular calcium concentration ([Ca(2+)](i)) and protein kinase C (PKC) activity. We show that the Shh-induced increase in the Gli1 mRNA level requires [Ca(2+)](i) and PKC. Shh increased the phosphorylation of epidermal growth factor receptor (EGFR), which is blocked by the matrix metalloproteinase inhibitor. Subsequently, Shh increased the nuclear factor (NF)-kappaB p65 phosphorylation, which was inhibited by blocking PKC and EGFR tyrosine kinase. Shh also increased the level of the cell cycle regulatory proteins in a dose-dependent manner. However, Shh decreased the levels of the cyclin-dependent kinase inhibitory proteins. The effect of Shh on these proteins was inhibited by blocking PKC, EGFR, and NF-kappaB as well as transfection of Gli1 small interfering RNA (siRNA). Finally, Shh-induced progression of the G1/S-phase was blocked by the inhibition of PKC and EGFR tyrosine kinase. In conclusion, Shh stimulates mouse ES cell proliferation through Gli1 activation as well as Ca(2+)/PKC and EGFR. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Jung Sun Heo
- Department of Veterinary Physiology, Biotherapy Human Resources Center, College of Veterinary Medicine, Chonnam National University, Gwangju, Korea
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Abstract
G proteins provide signal-coupling mechanisms to heptahelical cell surface receptors and are critically involved in the regulation of different mitogen-activated protein kinase (MAPK) networks. The four classes of G proteins, defined by the G(s), G(i), G(q) and G(12) families, regulate ERK1/2, JNK, p38MAPK, ERK5 and ERK6 modules by different mechanisms. The alpha- as well as betagamma-subunits are involved in the regulation of these MAPK modules in a context-specific manner. While the alpha- and betagamma-subunits primarily regulate the MAPK pathways via their respective effector-mediated signaling pathways, recent studies have unraveled several novel signaling intermediates including receptor tyrosine kinases and small GTPases through which these G-protein subunits positively as well as negatively regulate specific MAPK modules. Multiple mechanisms together with specific scaffold proteins that can link G-protein-coupled receptors or G proteins to distinct MAPK modules contribute to the context-specific and spatio-temporal regulation of mitogen-activated protein signaling networks by G proteins.
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Affiliation(s)
- Z G Goldsmith
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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Boucher I, Yang L, Mayo C, Klepeis V, Trinkaus-Randall V. Injury and nucleotides induce phosphorylation of epidermal growth factor receptor: MMP and HB-EGF dependent pathway. Exp Eye Res 2007; 85:130-41. [PMID: 17490650 PMCID: PMC2577227 DOI: 10.1016/j.exer.2007.03.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Revised: 02/22/2007] [Accepted: 03/19/2007] [Indexed: 11/30/2022]
Abstract
The early events that occur rapidly after injury trigger signal cascades that are essential for proper wound closure of corneal epithelial cells. We hypothesize that injury releases ATP, which stimulates purinergic receptors and elicits the phosphorylation of epidermal growth factor receptor (EGFR) tyrosine residues and subsequent cell migration by a MMP and HB-EGF dependent pathway. We demonstrated that the inhibition of purinergic receptors with the antagonist, Reactive Blue 2, abrogated the phosphorylation of EGFR and ERK. Pre-incubation of cells with the EGFR kinase inhibitor, AG1478, and subsequent stimulation by injury or ATP resulted in a decrease in phosphorylation of EGFR and migration. Furthermore, downregulation of EGFR by siRNA, inhibited the EGF-induced intracellular Ca(2+) wave. However, the response to injury and ATP was retained indicating the presence of two signaling pathways. Inhibition with either CRM197 or TIMP-3 decreased injury and nucleotide-induced phosphorylation of both EGFR and ERK. Incubation in the presence of a functional blocking antibody to HB-EGF also resulted in a decrease in the phosphorylation of EGFR. In addition, cell migration was inhibited by CRM197 and rescued when cells were incubated with HB-EGF. We showed that injury-induced phosphorylation of specific tyrosine residues and found that a similar pattern of phosphorylation was induced by trinucleotides. These studies indicate that injury-induced purinergic receptor activation leads to phosphorylation of EGFR, ERK and migration.
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Affiliation(s)
- Ilene Boucher
- Department of Biochemistry, Boston University School of Medicine Boston, MA 02118
| | - LingLing Yang
- Department of Biochemistry, Boston University School of Medicine Boston, MA 02118
| | - Courtney Mayo
- Department of Biochemistry, Boston University School of Medicine Boston, MA 02118
| | - Veronica Klepeis
- Department of Ophthalmology Boston University School of Medicine Boston, MA 02118
| | - Vickery Trinkaus-Randall
- Department of Biochemistry, Boston University School of Medicine Boston, MA 02118
- Department of Ophthalmology Boston University School of Medicine Boston, MA 02118
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Maudsley S, Naor Z, Bonfil D, Davidson L, Karali D, Pawson AJ, Larder R, Pope C, Nelson N, Millar RP, Brown P. Proline-rich tyrosine kinase 2 mediates gonadotropin-releasing hormone signaling to a specific extracellularly regulated kinase-sensitive transcriptional locus in the luteinizing hormone beta-subunit gene. Mol Endocrinol 2007; 21:1216-33. [PMID: 17327421 PMCID: PMC1951533 DOI: 10.1210/me.2006-0053] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
G protein-coupled receptor regulation of gene transcription primarily occurs through the phosphorylation of transcription factors by MAPKs. This requires transduction of an activating signal via scaffold proteins that can ultimately determine the outcome by binding signaling kinases and adapter proteins with effects on the target transcription factor and locus of activation. By investigating these mechanisms, we have elucidated how pituitary gonadotrope cells decode an input GnRH signal into coherent transcriptional output from the LH beta-subunit gene promoter. We show that GnRH activates c-Src and multiple members of the MAPK family, c-Jun NH2-terminal kinase 1/2, p38MAPK, and ERK1/2. Using dominant-negative point mutations and chemical inhibitors, we identified that calcium-dependent proline-rich tyrosine kinase 2 specifically acts as a scaffold for a focal adhesion/cytoskeleton-dependent complex comprised of c-Src, Grb2, and mSos that translocates an ERK-activating signal to the nucleus. The locus of action of ERK was specifically mapped to early growth response-1 (Egr-1) DNA binding sites within the LH beta-subunit gene proximal promoter, which was also activated by p38MAPK, but not c-Jun NH2-terminal kinase 1/2. Egr-1 was confirmed as the transcription factor target of ERK and p38MAPK by blockade of protein expression, transcriptional activity, and DNA binding. We have identified a novel GnRH-activated proline-rich tyrosine kinase 2-dependent ERK-mediated signal transduction pathway that specifically regulates Egr-1 activation of the LH beta-subunit proximal gene promoter, and thus provide insight into the molecular mechanisms required for differential regulation of gonadotropin gene expression.
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Affiliation(s)
- Stuart Maudsley
- Medical Research Council Human Reproductive Sciences Unit, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, Scotland, United Kingdom
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Park SY, Li H, Avraham S. RAFTK/Pyk2 regulates EGF-induced PC12 cell spreading and movement. Cell Signal 2007; 19:289-300. [PMID: 16945503 DOI: 10.1016/j.cellsig.2006.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 06/29/2006] [Accepted: 07/04/2006] [Indexed: 01/13/2023]
Abstract
The protein tyrosine kinase RAFTK, also termed Pyk2, is a member of the focal adhesion kinase (FAK) subfamily. In this report, we show the role of RAFTK in neuroendocrine PC12 cells upon epidermal growth factor (EGF) stimulation. Following EGF treatment, we observed that RAFTK was tyrosine-phosphorylated in a time- and dose-dependent manner, while FAK was constitutively phosphorylated and primarily regulated by cell adhesion. Moreover, we found that RAFTK associated with the phosphorylated EGF receptor (EGFR) upon EGF stimulation. RAFTK phosphorylation was mediated primarily through PLCgamma-IP3-Ca(2+) signaling and partially through PI3-Kinase. Furthermore, overexpression of PRNK, a specific dominant-negative construct of RAFTK, was sufficient to block EGF-induced cell spreading and movement. Paxillin, a key modulator of the actin cytoskeleton and an RAFTK substrate, was also phosphorylated following EGF treatment. EGF induced a dynamic reorganization of RAFTK and paxillin at neuronal adhesion sites, with the specific localization of paxillin at the inner juxtaposition of RAFTK. Additionally, we observed that RAFTK associated with the scaffold protein c-Cbl and mediated its phosphorylation. Our data demonstrate that while FAK mediated cell adhesion, RAFTK was localized at the cytoplasm where it mediated inside-out signaling through intracellular Ca(2+), thus leading to cell spreading and movement upon EGF stimulation.
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Affiliation(s)
- Shin-Young Park
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Harvard Institutes of Medicine, 4 Blackfan Circle, Boston, MA 02215, USA
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Abbracchio MP, Burnstock G, Boeynaems JM, Barnard EA, Boyer JL, Kennedy C, Knight GE, Fumagalli M, Gachet C, Jacobson KA, Weisman GA. International Union of Pharmacology LVIII: update on the P2Y G protein-coupled nucleotide receptors: from molecular mechanisms and pathophysiology to therapy. Pharmacol Rev 2006; 58:281-341. [PMID: 16968944 PMCID: PMC3471216 DOI: 10.1124/pr.58.3.3] [Citation(s) in RCA: 987] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
There have been many advances in our knowledge about different aspects of P2Y receptor signaling since the last review published by our International Union of Pharmacology subcommittee. More receptor subtypes have been cloned and characterized and most orphan receptors de-orphanized, so that it is now possible to provide a basis for a future subdivision of P2Y receptor subtypes. More is known about the functional elements of the P2Y receptor molecules and the signaling pathways involved, including interactions with ion channels. There have been substantial developments in the design of selective agonists and antagonists to some of the P2Y receptor subtypes. There are new findings about the mechanisms underlying nucleotide release and ectoenzymatic nucleotide breakdown. Interactions between P2Y receptors and receptors to other signaling molecules have been explored as well as P2Y-mediated control of gene transcription. The distribution and roles of P2Y receptor subtypes in many different cell types are better understood and P2Y receptor-related compounds are being explored for therapeutic purposes. These and other advances are discussed in the present review.
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Affiliation(s)
- Maria P Abbracchio
- Department of Pharmacological Sciences, University of Milan, Milan, Italy
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Lakshmi S, Joshi PG. Activation of Src/kinase/phospholipase C/mitogen-activated protein kinase and induction of neurite expression by ATP, independent of nerve growth factor. Neuroscience 2006; 141:179-89. [PMID: 16730415 DOI: 10.1016/j.neuroscience.2006.03.074] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 03/27/2006] [Accepted: 03/29/2006] [Indexed: 12/18/2022]
Abstract
Extracellular ATP has been reported to potentiate the neurite outgrowth induced by nerve growth factor. In the present study the neurotrophic effect of ATP and other nucleotides was examined in mouse neuroblastoma neuro2a cells which lack nerve growth factor receptor. Exposure of neuro2a cells to ATP resulted in a dramatic increase in neurite bearing cells as compared with untreated control cells. Experiments performed with purinergic receptor agonists and antagonists suggest that the ATP stimulates neurite outgrowth via P2 receptors. Neurite outgrowth was completely blocked by P2 receptor antagonist suramin whereas the P1 receptor antagonist CGS15943 was ineffective. P1 receptor agonist 5'-(N-ethylcarboxamido)adenosine failed to induce neurite outgrowth. The potency order of different P2 receptor agonists was ATP=ATPgammaS>ADP>>2Me-S-ATP. It was insensitive to UTP and antagonist pyridoxal phosphate-6-azo (benzene-2,4-disulfonic acid) suggesting the involvement of P2Y11 receptor in the observed neuritogenic effect. The signaling pathway leading to ATP-induced neuritogenesis was investigated. The neuritogenic effect of ATP is independent of rise in intracellular Ca(2+) as pharmacological profile of neuritogenic P2Y receptor does not match with that of P2Y2 receptor associated with [Ca(2+)](i) signaling cascade. Exposure of cells to ATP caused activation of Src kinase, phospholipase Cgamma and extracellular signal-regulated kinases ERK1/2. Mitogen-activated protein kinase (MAPK) inhibitor U0126 drastically reduced the number of neurite bearing cells in ATP-treated cultures implying that the neurotrophic effect of ATP is mediated by MAPK. Our results demonstrate that ATP can stimulate neurite outgrowth independent of other neurotrophic factors and can be an effective trophic agent.
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Affiliation(s)
- S Lakshmi
- Department of Biophysics, National Institute of Mental Health and Neurosciences, Bangalore 560 029, India
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Zimmermann H. Nucleotide signaling in nervous system development. Pflugers Arch 2006; 452:573-88. [PMID: 16639549 DOI: 10.1007/s00424-006-0067-4] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2006] [Accepted: 03/06/2006] [Indexed: 11/24/2022]
Abstract
The development of the nervous system requires complex series of cellular programming and intercellular communication events that lead from the early neural induction to the formation of a highly structured central and peripheral nervous system. Neurogenesis continuously takes place also in select regions of the adult mammalian brain. During the past years, a multiplicity of cellular control mechanisms has been identified, ranging from differential transcriptional mediators to inducers or inhibitors of cell specification or neurite outgrowth. While the identification of transcription factors typical for the stage-specific progression has been a topic of key interest for many years, less is known concerning the potential multiplicity of relevant intercellular signaling pathways and the fine tuning of epigenetic gene regulation. Nucleotide receptors can induce a multiplicity of cellular signaling pathways and are involved in multiple molecular interactions, thus opening the possibility of cross talk between several signaling pathways, including growth factors, cytokines, and extracellular matrix components. An increasing number of studies provides evidence for a role of nucleotide signaling in nervous system development. This includes progenitor cell proliferation, cell migration, neuronal and glial cellular interaction and differentiation, and synaptic network formation.
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Affiliation(s)
- Herbert Zimmermann
- Institut fuer Zellbiologie und Neurowissenschaft, Biozentrum der J.W. Goethe-Universitaet, Max-von-Lane-Str. 9, 60438, Frankfurt am Main, Germany.
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Kim JH, Kim HJ. Direct involvement of G protein alpha(q/11) subunit in regulation of muscarinic receptor-mediated sAPPalpha release. Arch Pharm Res 2006; 28:1275-81. [PMID: 16350855 DOI: 10.1007/bf02978212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The G(q/11) protein-coupled receptors, such as muscarinic (M1 & M3) receptors, have been shown to regulate the release of a soluble amyloid precursor protein (sAPPalpha) produced from alpha-secretase processing. However, there is no direct evidence for the precise characteristics of G proteins, and the signaling mechanism for the regulation of G(q/11) protein-coupled receptor-mediated sAPPalpha release is not clearly understood. This study examined whether the muscarinic receptor-mediated release of sAPPalpha is directly regulated by Galpha(q/11) proteins. The HEK293 cells were transiently cotransfected with muscarinic M3 receptors and a dominant-negative minigene construct of the G protein alpha subunit. The sAPPalpha release in the media was measured using an antibody specific for sAPP. The sAPPalpha release enhancement induced by muscarinic receptor stimulation was decreased by a G(q/11) minigene construct, whereas it was not blocked by a control minigene construct (the Galpha carboxy peptide in random order, Galpha(q)R) or Galpha(i) constructs. This indicated a direct role of the Galpha(q/11) protein in the regulation of muscarinic M3 receptor-mediated sAPPalpha release. We also investigated whether the transactivation of the epidermal growth factor receptor (EGFR) by a muscarinic agonist could regulate the sAPPalpha release in SH-SY5Y cells. Pretreatment of a specific EGFR kinase inhibitor, tyrophostin AG1478 (250 nM), blocked the EGF-stimulated sAPPalpha release, but did not block the oxoM-stimulated sAPPalpha release. This demonstrated that the transactivation of the EGFR by muscarinic receptor activation was not involved in the muscarinic receptor-mediated sAPPalpha release.
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Affiliation(s)
- Jin Hyoung Kim
- Division of Pharmaceutical Bioscience, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
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Weisman GA, Wang M, Kong Q, Chorna NE, Neary JT, Sun GY, González FA, Seye CI, Erb L. Molecular determinants of P2Y2 nucleotide receptor function: implications for proliferative and inflammatory pathways in astrocytes. Mol Neurobiol 2006; 31:169-83. [PMID: 15953819 DOI: 10.1385/mn:31:1-3:169] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2004] [Accepted: 11/15/2004] [Indexed: 01/05/2023]
Abstract
In the mammalian nervous system, P2 nucleotide receptors mediate neurotransmission, release of proinflammatory cytokines, and reactive astrogliosis. Extracellular nucleotides activate multiple P2 receptors in neurons and glial cells, including G protein-coupled P2Y receptors and P2X receptors, which are ligand-gated ion channels. In glial cells, the P2Y2 receptor subtype, distinguished by its ability to be equipotently activated by ATP and UTP, is coupled to pro-inflammatory signaling pathways. In situ hybridization studies with rodent brain slices indicate that P2Y2 receptors are expressed primarily in the hippocampus and cerebellum. Astrocytes express several P2 receptor subtypes, including P2Y2 receptors whose activation stimulates cell proliferation and migration. P2Y2 receptors, via an RGD (Arg-Gly-Asp) motif in their first extracellular loop, bind to alphavbeta3/beta5 integrins, whereupon P2Y2 receptor activation stimulates integrin signaling pathways that regulate cytoskeletal reorganization and cell motility. The C-terminus of the P2Y2 receptor contains two Src-homology-3 (SH3)-binding domains that upon receptor activation, promote association with Src and transactivation of growth factor receptors. Together, our results indicate that P2Y2 receptors complex with both integrins and growth factor receptors to activate multiple signaling pathways. Thus, P2Y2 receptors present novel targets to control reactive astrogliosis in neurodegenerative diseases.
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Affiliation(s)
- Gary A Weisman
- Department of Biochemistry and Neuroscience Program, University of Missouri-Columbia, Columbia, MO, USA.
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Sak K, Illes P. Neuronal and glial cell lines as model systems for studying P2Y receptor pharmacology. Neurochem Int 2005; 47:401-12. [PMID: 16081187 DOI: 10.1016/j.neuint.2005.05.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Accepted: 05/31/2005] [Indexed: 11/18/2022]
Abstract
Investigation of the role of extracellular nucleotides in nervous system has been one of the main topics of the P2Y receptor research throughout the years. In parallel to numerous studies on primary culture systems, various neuronal and non-neuronal cell lines have been used to model in vitro the processes mediated by extracellular nucleotides. In this review article, a survey of expression profiles of G protein-coupled P2Y receptor subtypes in nervous-system-derived cell lines is presented, by analysing the receptor expression at the mRNA, protein, and functional level. The variability of receptor expression profiles in established cell lines is further discussed, bringing forward some general properties for neuronal and glial malignant cell lines.
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Affiliation(s)
- Katrin Sak
- Rudolf-Boehm Institute of Pharmacology and Toxicology, and Interdisciplinary Center for Clinical Research, Medical Faculty, University of Leipzig, D-04107 Leipzig, Germany.
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Baker OJ, Camden JM, Ratchford AM, Seye CI, Erb L, Weisman GA. Differential coupling of the P2Y1 receptor to Galpha14 and Galphaq/11 proteins during the development of the rat salivary gland. Arch Oral Biol 2005; 51:359-70. [PMID: 16336941 DOI: 10.1016/j.archoralbio.2005.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 10/11/2005] [Accepted: 10/14/2005] [Indexed: 02/06/2023]
Abstract
UNLABELLED In rat submandibular gland (SMG), the P2Y1 receptor (P2Y1R) mediates increases in the intracellular calcium concentration, [Ca2+]i that diminish as the animal ages from 1 to 4-6 weeks. However, P2Y1R mRNA levels do not change with age, suggesting that the age-dependent decrease in the [Ca2+]i response to P2Y1R agonists may be due to alterations in the activity of a component of the P2Y1R signalling pathway. OBJECTIVES To assess whether the decrease in P2Y1R-mediated intracellular calcium signalling in SMG cells as rats age is due to a decrease in P2Y1R coupling to G proteins or to a decrease in the expression of a cognate G protein. DESIGN SMG cells were isolated from Sprague-Dawley rats. P2Y1R function was assessed by measuring 2-MeSADP-induced increases in [Ca2+]i and ERK1/2 activation. P2Y(1)R-mediated activation of G proteins was determined by the [35S]GTPgammaS binding assay. Gq protein expression was determined by RT-PCR, Northern, and Western analysis. RESULTS In SMG cells from 1-week-old rats, two bands (52 and 42kDa) were detected using anti-Galpha14 antibody, whereas in SMG cells from 4- to 6-week-old rats only the 42 kDa band was detected. Furthermore, 2-MeSADP-induced GTPgamma35S binding to Galpha14 and Galphaq/11 decreases in SMG cells from 4- to 6-week-old rats as compared to 1-week-old rats. CONCLUSIONS These findings suggest that the age-dependent decrease in P2Y1R-mediated intracellular calcium signalling in rat SMG cells is due to a loss of 52 kDa Galpha14 and indicate the differential coupling of the P2Y1R to Galpha14 and Galphaq/11 as the gland develops.
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Affiliation(s)
- Olga J Baker
- Department of Biochemistry, University of Missouri-Columbia, 540E Life Sciences Center, 1201 Rollins Road, Columbia, MO 65211-7310, USA
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48
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Kaczmarek E, Erb L, Koziak K, Jarzyna R, Wink MR, Guckelberger O, Blusztajn JK, Trinkaus-Randall V, Weisman GA, Robson SC. Modulation of endothelial cell migration by extracellular nucleotides: involvement of focal adhesion kinase and phosphatidylinositol 3-kinase-mediated pathways. Thromb Haemost 2005; 93:735-42. [PMID: 15841322 PMCID: PMC2830093 DOI: 10.1160/th04-09-0576] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Extracellular nucleotides bind to type-2 purinergic/pyrimidinergic (P2) receptors that mediate various responses, such as cell activation, proliferation and apoptosis, implicated in inflammatory processes. The role of P2 receptors and their associated signal transduction pathways in endothelial cell responses has not been fully investigated. Here, it is shown that stimulation of human umbilical vein endothelial cells (HUVEC) with extracellular ATP or UTP increased intracellular free calcium ion concentrations ([Ca(2+)](i)), induced phosphorylation of focal adhesion kinase (FAK), p130(cas) and paxillin, and caused cytoskeletal rearrangements with consequent cell migration. Furthermore, UTP increased migration of HUVEC in a phosphatidylinositol 3-kinase (PI3-K)-dependent manner. BAPTA or thapsigargin inhibited the extracellular nucleotide-induced increase in [Ca(2+)](i), a response crucial for both FAK phosphorylation and cell migration. Furthermore, long-term exposure of HUVEC to ATP and UTP, agonists of the G protein-coupled P2Y2 and P2Y4 receptor subtypes, caused upregulation of alpha(v) integrin expression, a cell adhesion molecule known to directly interact with P2Y2 receptors. Our results suggest that extracellular nucleotides modulate signaling pathways in HUVEC influencing cell functions, such as cytoskeletal changes, cellular adhesion and motility, typically associated with integrin-activation and the action of growth factors. We propose that P2Y2 and possibly P2Y4 receptors mediate those responses that are important in vascular inflammation, atherosclerosis and angiogenesis.
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Affiliation(s)
- Elzbieta Kaczmarek
- Beth Israel Deaconess Medical Center, Department of Medicine, Harvard Medical School, Boston, MA 02215, USA.
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Wang M, Kong Q, Gonzalez FA, Sun G, Erb L, Seye C, Weisman GA. P2Y nucleotide receptor interaction with alpha integrin mediates astrocyte migration. J Neurochem 2005; 95:630-40. [PMID: 16135088 DOI: 10.1111/j.1471-4159.2005.03408.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Astrocytes become activated in response to brain injury, as characterized by increased expression of glial fibrillary acidic protein (GFAP) and increased rates of cell migration and proliferation. Damage to brain cells causes the release of cytoplasmic nucleotides, such as ATP and uridine 5'-triphosphate (UTP), ligands for P2 nucleotide receptors. Results in this study with primary rat astrocytes indicate that activation of a G protein-coupled P2Y(2) receptor for ATP and UTP increases GFAP expression and both chemotactic and chemokinetic cell migration. UTP-induced astrocyte migration was inhibited by silencing of P2Y(2) nucleotide receptor (P2Y(2)R) expression with siRNA of P2Y(2)R (P2Y(2)R siRNA). UTP also increased the expression in astrocytes of alpha(V)beta(3/5) integrins that are known to interact directly with the P2Y(2)R to modulate its function. Anti-alpha(V) integrin antibodies prevented UTP-stimulated astrocyte migration, suggesting that P2Y(2)R/alpha(V) interactions mediate the activation of astrocytes by UTP. P2Y(2)R-mediated astrocyte migration required the activation of the phosphatidylinositol-3-kinase (PI3-K)/protein kinase B (Akt) and the mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) signaling pathways, responses that also were inhibited by anti-alpha(V) integrin antibody. These results suggest that P2Y(2)Rs and their associated signaling pathways may be important factors regulating astrogliosis in brain disorders.
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Affiliation(s)
- Min Wang
- Interdisciplinary Neuroscience Program, University of Missouri-Columbia, Missouri 65211, USA
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50
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Kawanabe Y, Nauli SM. Involvement of extracellular Ca2+ influx through voltage-independent Ca2+ channels in endothelin-1 function. Cell Signal 2005; 17:911-6. [PMID: 15894164 DOI: 10.1016/j.cellsig.2005.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Accepted: 01/07/2005] [Indexed: 11/20/2022]
Abstract
This article reviews the types and roles of voltage-independent Ca(2+) channels involved in the endothelin-1 (ET-1)-induced functional responses such as vascular contraction, cell proliferation, and intracellular Ca(2+)-dependent signaling pathways and discusses the molecular mechanisms for the activation of voltage-independent Ca(2+) channels by ET-1. ET-1 activates some types of voltage-independent Ca(2+) channels, such as Ca(2+)-permeable nonselective cation channels (NSCCs) and store-operated Ca(2+) channels (SOCC). Extracellular Ca(2+) influx through these voltage-independent Ca(2+) channels plays essential roles in ET-1-induced vascular contraction, cell proliferation, activation of epidermal growth factor receptor tyrosine kinase, regulation of proline-rich tyrosine kinase, and release of arachidonic acid. The experiments using various constructs of endothelin receptors reveal the importance of G(q) and G(12) families in activation of these Ca(2+) channels by ET-1. These findings provide a potential therapeutic mechanism of a functional interrelationship between G(q)/G(12) proteins and voltage-independent Ca(2+) channels in the pathophysiology of ET-1, such as in chronic heart failure, hypertension, and cerebral vasospasm.
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Affiliation(s)
- Yoshifumi Kawanabe
- Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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