1
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Cruz-Muñoz JR, Valdez-Morales EE, Barajas-Espinosa A, Barrios-García T, Liñán-Rico A, Guerrero-Alba R. Gene expression alterations of purinergic signaling components in obesity-associated intestinal low-grade inflammation in type 2 diabetes. Purinergic Signal 2024:10.1007/s11302-024-10006-1. [PMID: 38587723 DOI: 10.1007/s11302-024-10006-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 03/26/2024] [Indexed: 04/09/2024] Open
Abstract
Intestinal low-grade inflammation induced by a high-fat diet has been found to detonate chronic systemic inflammation, which is a hallmark of obesity, and precede the apparition of insulin resistance, a key factor for developing type 2 diabetes (T2D). Aberrant purinergic signaling pathways have been implicated in the pathogenesis of inflammatory bowel disease and other gastrointestinal diseases. However, their role in the gut inflammation associated with obesity and T2D remains unexplored. C57BL/6 J mice were fed a cafeteria diet for 21 weeks and received one injection of streptozotocin in their sixth week into the diet. The gene expression profile of purinergic signaling components in colon tissue was assessed by RT-qPCR. Compared to control mice, the treated group had a significant reduction in colonic length and mucosal and muscular layer thickness accompanied by increased NF-κB and IL-1β mRNA expression. Furthermore, colonic P2X2, P2X7, and A3R gene expression levels were lower, while the P2Y2, NT5E, and ADA expression levels increased. In conclusion, these data suggest that these purinergic signaling components possibly play a role in intestinal low-grade inflammation associated with obesity and T2D and thus could represent a novel therapeutic target for the treatment of the metabolic complications related to these diseases.
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Affiliation(s)
- José R Cruz-Muñoz
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags, México
| | - Eduardo E Valdez-Morales
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags, México
| | - Alma Barajas-Espinosa
- Escuela Superior de Huejutla, Universidad Autónoma del Estado de Hidalgo, Huejutla de Reyes, Hidalgo, México
| | - Tonatiuh Barrios-García
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags, México
| | - Andrómeda Liñán-Rico
- Centro Universitario de Investigaciones Biomédicas. Consejo Nacional de Humanidades, Ciencia y Tecnología (CONAHCYT), Universidad de Colima, Colima, México.
| | - Raquel Guerrero-Alba
- Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Ags, México.
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2
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Huang H, He YM, Lin MM, Wang Y, Zhang X, Liang L, He X. P2X7Rs: new therapeutic targets for osteoporosis. Purinergic Signal 2023; 19:207-219. [PMID: 35106736 PMCID: PMC9984661 DOI: 10.1007/s11302-021-09836-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 12/17/2021] [Indexed: 02/05/2023] Open
Abstract
Increasing evidence suggests that both the occurrence and progression of osteoporosis are associated with inflammation, especially in primary osteoporosis. The maintenance of skeletal homeostasis is dependent on the complex regulation of bone metabolism. Numerous evidence suggested that purinoceptor networks are essential for bone homeostasis. In this review, the relationship between inflammation and the development of osteoporosis and the role of P2X7 receptor (P2X7R) in regulating the dynamic regulation of bone reconstruction were covered. We also discussed how P2X7R regulates the balance between resorption and bone formation by osteoblasts and reviewed the relevance of P2X7R polymorphisms in skeletal physiology. Finally, we analyzed potential targets of P2X7R for osteoporosis.
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Affiliation(s)
- Haoyun Huang
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, China
| | - Yu-Mei He
- School of Sports Medicine and Health, Chengdu Sports University, Chengdu, 610041, China
| | - Miao-Miao Lin
- School of Sports Medicine and Health, Chengdu Sports University, Chengdu, 610041, China
| | - Yanchao Wang
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiaomei Zhang
- Laboratory Animal Center of Sichuan University, Chengdu, 610041, China
| | - Li Liang
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Xueling He
- Laboratory Animal Center of Sichuan University, Chengdu, 610041, China.
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3
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Janho dit Hreich S, Juhel T, Hofman P, Vouret-Craviari V. Protocol for Evaluating In Vivo the Activation of the P2RX7 Immunomodulator. Biol Proced Online 2023; 25:1. [PMID: 36600200 PMCID: PMC9811721 DOI: 10.1186/s12575-022-00188-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 12/13/2022] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND P2RX7 is a purinergic receptor with pleiotropic activities that is activated by high levels of extracellular ATP that are found in inflamed tissues. P2RX7 has immunomodulatory and anti-tumor proprieties and is therefore a therapeutic target for various diseases. Several compounds are developed to either inhibit or enhance its activation. However, studying their effect on P2RX7's activities is limited to in vitro and ex vivo studies that require the use of unphysiological media that could affect its activation. Up to now, the only way to assess the activity of P2RX7 modulators on the receptor in vivo was in an indirect manner. RESULTS We successfully developed a protocol allowing the detection of P2RX7 activation in vivo in lungs of mice, by taking advantage of its unique macropore formation ability. The protocol is based on intranasal delivery of TO-PRO™-3, a non-permeant DNA intercalating dye, and fluorescence measurement by flow cytometry. We show that ATP enhances TO-PRO™-3 fluorescence mainly in lung immune cells of mice in a P2RX7-dependant manner. CONCLUSIONS The described approach has allowed the successful analysis of P2RX7 activity directly in the lungs of WT and transgenic C57BL6 mice. The provided detailed guidelines and recommendations will support the use of this protocol to study the potency of pharmacologic or biologic compounds targeting P2RX7.
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Affiliation(s)
- Serena Janho dit Hreich
- grid.463830.a0000 0004 8340 3111Université Côte d’Azur, CNRS, INSERM, IRCAN, 28 avenue de Valombrose, 06108 Nice, France ,grid.464719.90000 0004 0639 4696FHU OncoAge, Pasteur Hospital, 30 voie Romaine, 06001 Nice, France
| | - Thierry Juhel
- grid.463830.a0000 0004 8340 3111Université Côte d’Azur, CNRS, INSERM, IRCAN, 28 avenue de Valombrose, 06108 Nice, France
| | - Paul Hofman
- grid.463830.a0000 0004 8340 3111Université Côte d’Azur, CNRS, INSERM, IRCAN, 28 avenue de Valombrose, 06108 Nice, France ,grid.464719.90000 0004 0639 4696FHU OncoAge, Pasteur Hospital, 30 voie Romaine, 06001 Nice, France ,grid.464719.90000 0004 0639 4696Laboratory of Clinical and Experimental Pathology and Biobank, Pasteur Hospital, 30 voie Romaine, 06001 Nice, France ,grid.464719.90000 0004 0639 4696Hospital-Related Biobank (BB-0033-00025), Pasteur Hospital, 30 voie Romaine, 06001 Nice, France
| | - Valérie Vouret-Craviari
- grid.463830.a0000 0004 8340 3111Université Côte d’Azur, CNRS, INSERM, IRCAN, 28 avenue de Valombrose, 06108 Nice, France ,grid.464719.90000 0004 0639 4696FHU OncoAge, Pasteur Hospital, 30 voie Romaine, 06001 Nice, France
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4
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Purohit R, Bera AK. Pannexin 1 plays a pro-survival role by attenuating P2X7 receptor-mediated Ca 2+ influx. Cell Calcium 2021; 99:102458. [PMID: 34479067 DOI: 10.1016/j.ceca.2021.102458] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 07/27/2021] [Accepted: 08/16/2021] [Indexed: 10/20/2022]
Abstract
Extracellular ATP works as an autocrine and/or paracrine signaling molecule by activating plasma membrane-localized purinergic receptors. Stimulation of purinergic P2X7 receptor (P2X7R) increases cytosolic Ca2+ ([Ca2+]c), which in turn activates Pannexin 1 (Panx1) channel. In earlier studies, Panx1 and P2X7R have been shown to interact physically. Also, both the channels have been implicated in similar pathophysiological processes. In this study, we investigated the effect of Panx1 on P2X7R-mediated Ca2+influx. Panx1 attenuated P2X7R-mediated [Ca2+]c rise in CHO-K1 and HEK-293 cells. [Ca2+]c rise was higher in Panx1 knockdown astrocytes. The inhibitory effect was unaffected in the presence of Panx1 blocker, carbenoxolone. The region between 350th and 386th amino acid residues in the carboxyl terminus (CT) of Panx1 was found to be crucial for inhibiting P2X7R. Like full-length Panx1, the CT (350th to 426th amino acids) alone was able to attenuate the [Ca2+]c rise. Further, CT prevented cell death caused by P2X7R overactivation. Based on our results, we propose a novel pro-survival role of Panx1 exerted by modulating P2X7R.
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Affiliation(s)
- Rutambhara Purohit
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Amal Kanti Bera
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600 036, India.
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5
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Osteoclast Multinucleation: Review of Current Literature. Int J Mol Sci 2020; 21:ijms21165685. [PMID: 32784443 PMCID: PMC7461040 DOI: 10.3390/ijms21165685] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/14/2022] Open
Abstract
Multinucleation is a hallmark of osteoclast maturation. The unique and dynamic multinucleation process not only increases cell size but causes functional alterations through reconstruction of the cytoskeleton, creating the actin ring and ruffled border that enable bone resorption. Our understanding of the molecular mechanisms underlying osteoclast multinucleation has advanced considerably in this century, especially since the identification of DC-STAMP and OC-STAMP as “master fusogens”. Regarding the molecules and pathways surrounding these STAMPs, however, only limited progress has been made due to the absence of their ligands. Various molecules and mechanisms other than the STAMPs are involved in osteoclast multinucleation. In addition, several preclinical studies have explored chemicals that may be able to target osteoclast multinucleation, which could enable us to control pathogenic bone metabolism more precisely. In this review, we will focus on recent discoveries regarding the STAMPs and other molecules involved in osteoclast multinucleation.
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6
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Weitz JR, Jacques-Silva C, Qadir MMF, Umland O, Pereira E, Qureshi F, Tamayo A, Dominguez-Bendala J, Rodriguez-Diaz R, Almaça J, Caicedo A. Secretory Functions of Macrophages in the Human Pancreatic Islet Are Regulated by Endogenous Purinergic Signaling. Diabetes 2020; 69:1206-1218. [PMID: 32245801 PMCID: PMC7243286 DOI: 10.2337/db19-0687] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 03/26/2020] [Indexed: 12/22/2022]
Abstract
Endocrine cells of the pancreatic islet interact with their microenvironment to maintain tissue homeostasis. Communication with local macrophages is particularly important in this context, but the homeostatic functions of human islet macrophages are not known. In this study, we show that the human islet contains macrophages in perivascular regions that are the main local source of the anti-inflammatory cytokine interleukin-10 (IL-10) and the metalloproteinase MMP9. Macrophage production and secretion of these homeostatic factors are controlled by endogenous purinergic signals. In obese and diabetic states, macrophage expression of purinergic receptors MMP9 and IL-10 is reduced. We propose that in those states, exacerbated β-cell activity due to increased insulin demand and increased cell death produce high levels of ATP that downregulate purinergic receptor expression. Loss of ATP sensing in macrophages may reduce their secretory capacity.
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Affiliation(s)
- Jonathan R Weitz
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Carol Jacques-Silva
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL
| | - Mirza Muhammed Fahd Qadir
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL
- Molecular Cell and Developmental Biology, University of Miami Miller School of Medicine, Miami, FL
| | - Oliver Umland
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL
| | - Elizabeth Pereira
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Farhan Qureshi
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Molecular Cell and Developmental Biology, University of Miami Miller School of Medicine, Miami, FL
| | - Alejandro Tamayo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Juan Dominguez-Bendala
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL
- Molecular Cell and Developmental Biology, University of Miami Miller School of Medicine, Miami, FL
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL
| | - Rayner Rodriguez-Diaz
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Joana Almaça
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
| | - Alejandro Caicedo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL
- Molecular Cell and Developmental Biology, University of Miami Miller School of Medicine, Miami, FL
- Program in Neuroscience, University of Miami Miller School of Medicine, Miami, FL
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL
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7
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Ye Q, Li G, Liu S, Guan Y, Li Y, Li J, Jia H, Li X, Li Q, Huang R, Wang H, Zhang Y. Targeted disruption of adenosine kinase in myeloid monocyte cells increases osteoclastogenesis and bone resorption in mice. Int J Mol Med 2018; 41:2177-2184. [PMID: 29344645 DOI: 10.3892/ijmm.2018.3394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/05/2018] [Indexed: 11/05/2022] Open
Abstract
Adenosine kinase (ADK) serves an important role in intracellular adenosine clearance via phosphorylating adenosine to AMP. The role of adenosine and its receptors in the maintenance of bone homeostasis is well studied, particularly in osteoclastogenesis and bone resorption; however, the function of ADK in bone metabolism is still unclear. In the present study, utilizing the cre/floxp recombination system, mice with conditional loss of ADK function in myeloid monocyte cells were used to assess the effect of ADK deficiency on bone metabolism. Mice were evaluated by means of gross observation and bone histomorphometric analysis. Ex vivo osteoclast differentiation and bone resorption were also examined using genetic deletion and pharmacologic inhibition of ADK in osteoclasts. Compared with control mice, the results of the present study demonstrate that adult mice lacking ADK in the myeloid monocyte cells had reduced body weight and nasoanal length. The results of bone histomorphometric analysis revealed that bone mass was significantly decreased and osteoclastic parameters were increased in the study mice. Furthermore, in vitro cell culture revealed that inhibition of ADK function promoted osteoclast differentiation and bone resorption. Osteoclast‑associated gene expression, including tartrate‑resistant acid phosphatase, nuclear factor of activated T‑cells, cytoplasmic 1, matrix metalloproteinase 9, Cathepsin K and calcitonin receptor, was also significantly increased. These results suggest that mice with ADK deficiency have reduced bone formation due to increased osteoclastogenesis and bone resorption. The present study provides further insight into the mechanism by which ADK serves a key role in bone metabolism.
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Affiliation(s)
- Qiuying Ye
- Department of Food and Drugs, Qingyuan Polytechnic, Qingyuan, Guangdong 511510, P.R. China
| | - Ge Li
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Shuhua Liu
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Yalun Guan
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Yunfeng Li
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Jinling Li
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Huanhuan Jia
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Xuejiao Li
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Qingnan Li
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Ren Huang
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
| | - Hui Wang
- Department of Food and Drugs, Qingyuan Polytechnic, Qingyuan, Guangdong 511510, P.R. China
| | - Yu Zhang
- Guangdong Laboratory Animals Monitoring Institute, Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, Guangdong 510663, P.R. China
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8
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P2X7 receptor cross-talk regulates ATP-induced pannexin 1 internalization. Biochem J 2017; 474:2133-2144. [PMID: 28495860 DOI: 10.1042/bcj20170257] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/04/2017] [Accepted: 05/10/2017] [Indexed: 12/12/2022]
Abstract
In the nervous system, extracellular ATP levels transiently increase in physiological and pathophysiological circumstances, effecting key signalling pathways in plasticity and inflammation through purinergic receptors. Pannexin 1 (Panx1) forms ion- and metabolite-permeable channels that mediate ATP release and are particularly enriched in the nervous system. Our recent study demonstrated that elevation of extracellular ATP triggers Panx1 internalization in a concentration- and time-dependent manner. Notably, this effect was sensitive to inhibition of ionotropic P2X7 purinergic receptors (P2X7Rs). Here, we report our novel findings from the detailed investigation of the mechanism underlying P2X7R-Panx1 cross-talk in ATP-stimulated internalization. We demonstrate that extracellular ATP triggers and is required for the clustering of P2X7Rs and Panx1 on Neuro2a cells through an extracellular physical interaction with the Panx1 first extracellular loop (EL1). Importantly, disruption of P2X7R-Panx1 clustering by mutation of tryptophan 74 within the Panx1 EL1 inhibits Panx1 internalization. Notably, P2X7R-Panx1 clustering and internalization are independent of P2X7R-associated intracellular signalling pathways (Ca2+ influx and Src activation). Further analysis revealed that cholesterol is required for ATP-stimulated P2X7R-Panx1 clustering at the cell periphery. Taken together, our data suggest that extracellular ATP induces and is required for Panx1 EL1-mediated, cholesterol-dependent P2X7R-Panx1 clustering and endocytosis. These findings have important implications for understanding the role of Panx1 in the nervous system and provide important new insights into Panx1-P2X7R cross-talk.
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9
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Giannuzzo A, Pedersen SF, Novak I. The P2X7 receptor regulates cell survival, migration and invasion of pancreatic ductal adenocarcinoma cells. Mol Cancer 2015; 14:203. [PMID: 26607222 PMCID: PMC4660609 DOI: 10.1186/s12943-015-0472-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 11/18/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is presently one of the cancers with the worst survival rates and least effective treatments. Moreover, total deaths due to PDAC are predicted to increase in the next 15 years. Therefore, novel insights into basic mechanism of PDAC development and therapies are needed. PDAC is characterized by a complex microenvironment, in which cancer and stromal cells release different molecules, such as ATP. ATP can be transported and/or exocytosed from active cancer cells and released from dying cells in the necrotic core of the cancer. We hypothesized that one of the ATP receptors, the P2X7 receptor (P2X7R) could be an important player in PDAC behaviour. METHODS We determined the expression (real time PCR and Western blot) and localization (immunofluorescence) of P2X7R in human PDAC cell lines (AsPC-1, BxPC-3, Capan-1, MiaPaCa-2, Panc-1) and a "normal" human pancreatic duct epithelial cell line (HPDE). The function of P2X7R in proliferation (BrdU assay), migration (wound assay) and invasion (Boyden chamber with matrigel) was characterized. Furthermore, we studied P2X7R-dependent pore formation (YoPro-1 assay) and cell death (caspase and annexin V / propidium iodide assays). RESULTS We found higher expression of P2X7R protein in PDAC compared to HPDE cells. P2X7R had notable disparate effects on PDAC survival. Firstly, high concentrations of ATP or the specific P2X7R agonist, BzATP, had cytotoxic effects in all cell lines, and cell death was mediated by necrosis. Moreover, the P2X7R-pore antagonist, A438079, prevented ATP-induced pore formation and cell death. Second, in basal conditions and with low concentrations of ATP/BzATP, the P2X7R allosteric inhibitor AZ10606120 reduced proliferation in all PDAC cell lines. P2X7R also affected other key characteristics of cancer cell behavior. AZ10606120 reduced cell migration and invasion in PDAC cell lines compared to that of untreated/vehicle-treated control cells, and stimulation with sub-millimolar concentrations of ATP or BzATP substantially increased cell invasion. CONCLUSIONS PDAC cell lines overexpress P2X7R and the receptor plays crucial roles in cell survival, migration and invasion. Therefore, we propose that drugs targeting P2X7R could be exploited in therapy of pancreatic cancer.
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Affiliation(s)
- Andrea Giannuzzo
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, August Krogh Building, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
| | - Stine Falsig Pedersen
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, August Krogh Building, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
| | - Ivana Novak
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, August Krogh Building, Universitetsparken 13, DK-2100, Copenhagen, Denmark.
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10
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Moon SH, Latif M, Qasim M, Choi SW, Lee JY, Byun BJ, Saeed A, Kim SH. Synthesis, Characterization, and Biological Evaluation of Oxadiazole Derivatives Bearing 5-Phenyl-tetrazole as Osteoclast Differentiation Inhibitors. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Seong-Hee Moon
- Laboratory of Translational Therapeutics; Korea Research Institute of Chemical Technology; Daejeon 305-600 Republic of Korea
| | - Muhammad Latif
- Center for Catalytic Hydrocarbon Functionalization; Institute for Basic Science (IBS) and Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST); Daejeon 305-701 Korea
| | - Muhammad Qasim
- Department of Chemistry; Quaid-I-Azam University; Islamabad 45320 Pakistan
| | - Sik-Won Choi
- Laboratory of Translational Therapeutics; Korea Research Institute of Chemical Technology; Daejeon 305-600 Republic of Korea
| | - Joo Yun Lee
- Drug Discovery Platform Technology Group; Korea Research Institute of Chemical Technology; Daejeon 305-600 Republic of Korea
| | - Byung Jin Byun
- Drug Discovery Platform Technology Group; Korea Research Institute of Chemical Technology; Daejeon 305-600 Republic of Korea
| | - Aamer Saeed
- Department of Chemistry; Quaid-I-Azam University; Islamabad 45320 Pakistan
| | - Seong Hwan Kim
- Laboratory of Translational Therapeutics; Korea Research Institute of Chemical Technology; Daejeon 305-600 Republic of Korea
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11
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Abstract
Accumulating evidence now suggests that purinergic signalling exerts significant regulatory effects in the musculoskeletal system. In particular, it has emerged that extracellular nucleotides are key regulators of bone cell differentiation, survival and function. This review discusses our current understanding of the direct effects of purinergic signalling in bone, cartilage and muscle.
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Affiliation(s)
- Isabel R Orriss
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, United Kingdom.
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12
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Macrophage P2X7 receptor function is reduced during schistosomiasis: putative role of TGF- β1. Mediators Inflamm 2014; 2014:134974. [PMID: 25276050 PMCID: PMC4158569 DOI: 10.1155/2014/134974] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 07/14/2014] [Accepted: 08/04/2014] [Indexed: 12/05/2022] Open
Abstract
Schistosomiasis is a chronic inflammatory disease whose macrophages are involved in immunopathology modulation. Although P2X7 receptor signaling plays an important role in inflammatory responses mediated by macrophages, no reports have examined the role of P2X7 receptors in macrophage function during schistosomiasis. Thus, we evaluated P2X7 receptor function in peritoneal macrophages during schistosomiasis using an ATP-induced permeabilization assay and measurements of the intracellular Ca2+ concentration. ATP treatment induced significantly less permeabilization in macrophages from S. mansoni-infected mice than in control cells from uninfected animals. Furthermore, P2X7-mediated increases in intracellular Ca2+ levels were also reduced in macrophages from infected mice. TGF-β1 levels were increased in the peritoneal cavity of infected animals, and pretreatment of control macrophages with TGF-β1 reduced ATP-induced permeabilization, mimicking the effect of S. mansoni infection. Western blot and qRT-PCR data showed no difference in P2X7 protein and mRNA between uninfected, infected, and TGF-β1-treated groups. However, immunofluorescence analysis revealed reduced cell surface localization of P2X7 receptors in macrophages from infected and TGF-β1-treated mice compared to controls. Therefore, our data suggest that schistosomiasis reduces peritoneal macrophage P2X7 receptor signaling. This effect is likely due to the fact that infected mice have increased levels of TGF-β1, which reduces P2X7 receptor cell surface expression.
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13
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Li P, Liu C, Hu M, Long M, Zhang D, Huo B. Fluid flow-induced calcium response in osteoclasts: signaling pathways. Ann Biomed Eng 2014; 42:1250-60. [PMID: 24710796 DOI: 10.1007/s10439-014-0984-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 01/25/2014] [Indexed: 01/07/2023]
Abstract
Intracellular calcium oscillation and its downstream signaling in osteoclasts is believed to play critical roles in regulating bone resorption. Our previous study demonstrated that fluid shear stress (FSS) induced more calcium responsive peaks in the late differentiated osteoclasts than the early ones. In this paper, the signaling pathways of FSS-induced calcium response for the osteoclasts in different differentiation stages were studied. RAW264.7 macrophage cells were induced to differentiate into osteoclasts with the conditioned medium from MC3T3-E1 osteoblasts. Furthermore pharmacological agents were added to block the specific signaling pathways. Finally the cells were exposed to FSS at different levels (1 or 10 dyne/cm(2)) after being induced for 4 or 8 days. The results showed that the mechanosensitive, cation-selective channels, phospholipase C (PLC) and endoplasmic reticulum constituted the major signaling pathway for mechanical stimulation-induced calcium response in osteoclasts. Extracellular calcium or ATP involved with calcium oscillation in a FSS magnitude-dependent manner. This pathway study may help to give insight into the molecular mechanism of mechanical stimulation-regulated bone remodeling.
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Affiliation(s)
- Ping Li
- Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Beijing, 100081, People's Republic of China
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Burnstock G, Arnett TR, Orriss IR. Purinergic signalling in the musculoskeletal system. Purinergic Signal 2013; 9:541-72. [PMID: 23943493 PMCID: PMC3889393 DOI: 10.1007/s11302-013-9381-4] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 07/12/2013] [Indexed: 12/11/2022] Open
Abstract
It is now widely recognised that extracellular nucleotides, signalling via purinergic receptors, participate in numerous biological processes in most tissues. It has become evident that extracellular nucleotides have significant regulatory effects in the musculoskeletal system. In early development, ATP released from motor nerves along with acetylcholine acts as a cotransmitter in neuromuscular transmission; in mature animals, ATP functions as a neuromodulator. Purinergic receptors expressed by skeletal muscle and satellite cells play important pathophysiological roles in their development or repair. In many cell types, expression of purinergic receptors is often dependent on differentiation. For example, sequential expression of P2X5, P2Y1 and P2X2 receptors occurs during muscle regeneration in the mdx model of muscular dystrophy. In bone and cartilage cells, the functional effects of purinergic signalling appear to be largely negative. ATP stimulates the formation and activation of osteoclasts, the bone-destroying cells. Another role appears to be as a potent local inhibitor of mineralisation. In osteoblasts, the bone-forming cells, ATP acts via P2 receptors to limit bone mineralisation by inhibiting alkaline phosphatase expression and activity. Extracellular ATP additionally exerts significant effects on mineralisation via its hydrolysis product, pyrophosphate. Evidence now suggests that purinergic signalling is potentially important in several bone and joint disorders including osteoporosis, rheumatoid arthritis and cancers. Strategies for future musculoskeletal therapies might involve modulation of purinergic receptor function or of the ecto-nucleotidases responsible for ATP breakdown or ATP transport inhibitors.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Kaczmarek-Hájek K, Lörinczi E, Hausmann R, Nicke A. Molecular and functional properties of P2X receptors--recent progress and persisting challenges. Purinergic Signal 2012; 8:375-417. [PMID: 22547202 PMCID: PMC3360091 DOI: 10.1007/s11302-012-9314-7] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 10/18/2011] [Indexed: 12/16/2022] Open
Abstract
ATP-gated P2X receptors are trimeric ion channels that assemble as homo- or heteromers from seven cloned subunits. Transcripts and/or proteins of P2X subunits have been found in most, if not all, mammalian tissues and are being discovered in an increasing number of non-vertebrates. Both the first crystal structure of a P2X receptor and the generation of knockout (KO) mice for five of the seven cloned subtypes greatly advanced our understanding of their molecular and physiological function and their validation as drug targets. This review summarizes the current understanding of the structure and function of P2X receptors and gives an update on recent developments in the search for P2X subtype-selective ligands. It also provides an overview about the current knowledge of the regulation and modulation of P2X receptors on the cellular level and finally on their physiological roles as inferred from studies on KO mice.
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Affiliation(s)
- Karina Kaczmarek-Hájek
- Max Planck Institute for Experimental Medicine, Hermann Rein Str. 3, 37075, Göttingen, Germany
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16
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Modulating P2X7 Receptor Signaling during Rheumatoid Arthritis: New Therapeutic Approaches for Bisphosphonates. J Osteoporos 2012; 2012:408242. [PMID: 22830074 PMCID: PMC3399340 DOI: 10.1155/2012/408242] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 05/28/2012] [Accepted: 05/30/2012] [Indexed: 11/17/2022] Open
Abstract
P2X7 receptor-mediated purinergic signaling is a well-known mechanism involved in bone remodeling. The P2X7 receptor has been implicated in the pathophysiology of various bone and cartilage diseases, including rheumatoid arthritis (RA), a widespread and complex chronic inflammatory disorder. The P2X7 receptor induces the release into the synovial fluid of the proinflammatory factors (e.g., interleukin-1β, prostaglandins, and proteases) responsible for the clinical symptoms of RA. Thus, the P2X7 receptor is emerging as a novel anti-inflammatory therapeutic target, and various selective P2X7 receptor antagonists are under clinical trials. Extracellular ATP signaling acting through the P2X7 receptor is a complex and dynamic scenario, which varies over the course of inflammation. This signaling is partially modulated by the activity of ectonucleotidases, which degrade extracellular ATP to generate other active molecules such as adenosine or pyrophosphates. Recent evidence suggests differential extracellular metabolism of ATP during the resolution of inflammation to generate pyrophosphates. Extracellular pyrophosphate dampens proinflammatory signaling by promoting alternative macrophage activation. Our paper shows that bisphosphonates are metabolically stable pyrophosphate analogues that are able to mimic the anti-inflammatory function of pyrophosphates. Bisphosphonates are arising per se as promising anti-inflammatory drugs to treat RA, and this therapy could be improved when administrated in combination with P2X7 receptor antagonists.
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Genetic Background Strongly Influences the Bone Phenotype of P2X7 Receptor Knockout Mice. J Osteoporos 2012; 2012:391097. [PMID: 22934234 PMCID: PMC3425798 DOI: 10.1155/2012/391097] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 06/28/2012] [Accepted: 07/02/2012] [Indexed: 11/25/2022] Open
Abstract
The purinergic P2X7 receptor is expressed by bone cells and has been shown to be important in both bone formation and bone resorption. In this study we investigated the importance of the genetic background of the mouse strains on which the P2X7 knock-out models were based by comparing bone status of a new BALB/cJ P2X7(-/-) strain with a previous one based on the C57BL/6 strain. Female four-month-old mice from both strains were DXA scanned on a PIXImus densitometer; femurs were collected for bone strength measurements and serum for bone marker analysis. Bone-related parameters that were altered only slightly in the B6 P2X7(-/-) became significantly altered in the BALB/cJ P2X7(-/-) when compared to their wild type littermates. The BALB/cJ P2X7(-/-) showed reduced levels of serum C-telopeptide fragment (s-CTX), higher bone mineral density, and increased bone strength compared to the wild type littermates. In conclusion, we have shown that the genetic background of P2X7(-/-) mice strongly influences the bone phenotype of the P2X7(-/-) mice and that P2X7 has a more significant regulatory role in bone remodeling than found in previous studies.
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Association between P2X7 Receptor Polymorphisms and Bone Status in Mice. J Osteoporos 2012; 2012:637986. [PMID: 22919543 PMCID: PMC3420134 DOI: 10.1155/2012/637986] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 05/28/2012] [Indexed: 11/17/2022] Open
Abstract
Macrophages from mouse strains with the naturally occurring mutation P451L in the purinergic receptor P2X7 have impaired responses to agonists (1). Because P2X7 receptors are expressed in bone cells and are implicated in bone physiology, we asked whether strains with the P451L mutation have a different bone phenotype. By sequencing the most common strains of inbred mice, we found that only a few strains (BALB, NOD, NZW, and 129) were harboring the wild allelic version of the mutation (P451) in the gene for the purinergic receptor P2X7. The strains were compared by means of dual energy X-ray absorptiometry (DXA), bone markers, and three-point bending. Cultured osteoclasts were used in the ATP-induced pore formation assay. We found that strains with the P451 allele (BALB/cJ and 129X1/SvJ) had stronger femurs and higher levels of the bone resorption marker C-telopeptide collagen (CTX) compared to C57Bl/6 (B6) and DBA/2J mice. In strains with the 451L allele, pore-formation activity in osteoclasts in vitro was lower after application of ATP. In conclusion, two strains with the 451L allele of the naturally occurring mutation P451L, have weaker bones and lower levels of CTX, suggesting lower resorption levels in these animals, which could be related to the decreased ATP-induced pore formation observed in vitro. The importance of these findings for the interpretation of the earlier reported effects of P2X7 in mice is discussed, along with strategies in developing a murine model for testing the therapeutic effects of P2X7 agonists and antagonists upon postmenopausal osteoporosis.
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Lemaire I, Falzoni S, Zhang B, Pellegatti P, Di Virgilio F. The P2X7 receptor and Pannexin-1 are both required for the promotion of multinucleated macrophages by the inflammatory cytokine GM-CSF. THE JOURNAL OF IMMUNOLOGY 2011; 187:3878-87. [PMID: 21865551 DOI: 10.4049/jimmunol.1002780] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The P2X(7) receptor (P2X(7)R), an ATP-gated ion channel, has been implicated in the process of cell-to-cell fusion into multinucleated macrophages (MA), but its contribution to MA fusion driven by physiological/pathological stimuli is not clearly established. Based on several lines of evidence, we demonstrate that P2X(7)R is critical for the induction of multinucleated MA by the inflammatory cytokine GM-CSF: 1) pharmacological inhibition of P2X(7)R with oxidized ATP (oATP), KN-62, and the selective antagonist A740003 abrogated GM-CSF action on rat alveolar MA and murine peritoneal MA; 2) a murine J774 P2X(7) low MA clone, selected for defective P2X(7)R function, was unresponsive; 3) MA from mice lacking P2X(7)R failed to respond to GM-CSF, in contrast to wild-type. GM-CSF also stimulated ATP-induced membrane permeabilization in J774 P2X(7) high MA and rat alveolar MA, an effect absent in the P2X(7) low MA clone and inhibited by the P2X(7) blockers oATP and KN-62. Notably, the stimulatory effects of GM-CSF on pore formation and MA fusion were both inhibited by blocking functional Pannexin-1 (Panx-1), and GM-CSF failed to stimulate MA fusion in cells from Panx-1 knockout mice. We provide further evidence that extracellular ATP release from peritoneal MA is dependent on P2X(7) but not on Panx-1 expression and that its metabolism to adenosine mediates P2X(7)-dependent MA fusion. These data demonstrate that both P2X(7) and Panx-1 are required for GM-CSF promotion of MA fusion but likely act independently through different signaling pathway(s).
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Affiliation(s)
- Irma Lemaire
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada.
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Pellegatti P, Falzoni S, Donvito G, Lemaire I, Di Virgilio F. P2X7 receptor drives osteoclast fusion by increasing the extracellular adenosine concentration. FASEB J 2011; 25:1264-74. [PMID: 21233486 DOI: 10.1096/fj.10-169854] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Defects in bone homeostasis are a major health problem. Osteoclast differentiation and activation have a crucial role in bone remodeling in health and disease. Osteoclasts are bone-resorbing cells derived from mononuclear phagocyte progenitors. The key event in osteoclast formation is fusion of mononucleate precursors to form mature multinucleated osteclasts. Here we provide evidence of an absolute requirement for the P2X7 receptor, ATP release, and adenosine signaling in human osteoclast formation, as shown by the following findings: macrophage-colony stimulating factor/receptor activator for nuclear factor-κB ligand (M-CSF/RANKL)-stimulated fusion of human monocytes is fully prevented by an anti-P2X7 mAb, by specific P2X7 pharmacological antagonists, or by inhibition of CD39/NTPDase; fusion-competent monocytes release ATP via the P2X7 receptor; accelerated degradation of released ATP by addition of either apyrase or hexokinase strongly increases fusion; removal of extracellular adenosine by adenosine deaminase blocks, while addition of exogenous adenosine strongly potentiates, fusion; and pharmacologic stimulation of the adenosine A2A receptor increases, while selective A2A blockade inhibits, fusion. These results show that the purinergic axis plays a crucial and as yet undescribed role in osteoclast formation and reconcile previous evidence advocating a key role for either ATP or adenosine receptors in multinucleated giant cell formation.
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Affiliation(s)
- Patrizia Pellegatti
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, Interdisciplinary Center for the Study of Inflammation, University of Ferrara, Ferrara, Italy
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Rosenthal AK, Hempel D, Kurup IV, Masuda I, Ryan LM. Purine receptors modulate chondrocyte extracellular inorganic pyrophosphate production. Osteoarthritis Cartilage 2010; 18:1496-501. [PMID: 20709180 PMCID: PMC2975862 DOI: 10.1016/j.joca.2010.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 08/05/2010] [Accepted: 08/10/2010] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Extracellular inorganic pyrophosphate (ePPi) plays a key role in the regulation of normal and pathologic mineralization. The purpose of this work was to evaluate the role of P1 and P2 purine receptors in modulating ePPi production by articular chondrocytes. METHODS Porcine cartilage explants and chondrocyte monolayers were cultured in the presence of P1 agonists, or a P2 agonist or antagonist and inhibitors of P2 signaling. Ambient media ePPi concentrations were measured after 48-96h. RESULTS The P1 agonists NECA and CGS 21680 significantly decreased ePPi concentrations surrounding chondrocytes and cartilage explants. The P2 agonist, ADP, increased ePPi levels, and the P2 antagonist, suramin, decreased ePPi concentrations. Thapsigargin and 1,2 bis-(2-aminophenoxy)ethane-N,N,N'N'-tetra acetic acid (BAPTA), which dampen Ca(2+)-related P2 signaling, suppressed the response to ADP. CONCLUSIONS Purine receptors are important regulators of ePPi production by chondrocytes. P1 receptor stimulation diminishes and P2 receptor stimulation enhances ePPi production. Alterations in receptor signaling or aberrations of extracellular purine nucleotide metabolism resulting in abnormal quantities or proportions of P1 and P2 receptor ligands could foster changes in ePPi production that in turn affect mineralization. We propose a homeostatic role for extracellular purine nucleotides and purine receptors in stabilizing ePPi concentrations.
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Nissen N, Madsen JS, Bladbjerg EM, Beck Jensen JE, Jørgensen NR, Langdahl B, Abrahamsen B, Brixen K. No association between hip geometry and four common polymorphisms associated with fracture: the Danish osteoporosis prevention study. Calcif Tissue Int 2009; 84:276-85. [PMID: 19225709 DOI: 10.1007/s00223-009-9219-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2008] [Accepted: 01/16/2009] [Indexed: 10/21/2022]
Abstract
Both osteoporosis and hip geometry are independently associated with fracture risk. There is a significant genetic contribution to the risk of osteoporosis, and evidence provided by twin studies has suggested that hip geometry may also in part be genetically programmed. Polymorphisms in a number of genes, including those coding for methylene-tetrahydrofolate reductase (MTHFR c.677C > T), the purinergic P2X(7) receptor (Glu496Ala and Ile568Asn), and the low-density lipoprotein receptor-related protein 5 (LRP5 exon 9 [c.266A > G]), have been associated with an increased fracture incidence and/or reduced bone mineral density (BMD). The aim of the present study was to test whether these polymorphisms influence hip structural geometry in perimenopausal women. The four polymorphisms were genotyped in 800 healthy recently perimenopausal women never using hormone replacement therapy. BMD of the femoral neck was measured using a Hologic QDR-2000 densitometer and femoral neck axis length, neck width, neck shaft angle, and femoral head diameter were measured from the screen images. Genotype frequencies were compatible with Hardy-Weinberg equilibrium. No significant differences between homozygotes for the minor allele and carriers of the common allele regarding parameters of hip geometry were demonstrated. According to the anthropometric characteristics of the subjects, only body height in the MTHFR TT genotype group was significantly different from the combined CT/CC genotype group (P < 0.05). The geometric dimensions of the proximal femur in perimenopausal women are not associated with the MTHFR c.677C > T, P2X(7) (Glu496Ala), P2X(7) (Ile568Asn), and LRP5 exon 9 (c.266A > G) polymorphisms.
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Affiliation(s)
- N Nissen
- Department of Endocrinology, Odense University Hospital, University of Southern Denmark, Odense, 5000, Odense C, Denmark.
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Expression, signaling, and function of P2X7 receptors in bone. Purinergic Signal 2009; 5:205-21. [PMID: 19224395 DOI: 10.1007/s11302-009-9139-1] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Accepted: 09/16/2008] [Indexed: 01/01/2023] Open
Abstract
Nucleotides released from cells in response to mechanical stimulation or injury may serve as paracrine regulators of bone cell function. Extracellular nucleotides bind to multiple subtypes of P2 receptors on osteoblasts (the cells responsible for bone formation) and osteoclasts (cells with the unique ability to resorb mineralized tissues). Both cell lineages express the P2X7 receptor subtype. The skeletal phenotype of mice with targeted disruption of P2rx7 points to interesting roles for this receptor in the regulation of bone formation and resorption, as well as the response of the skeleton to mechanical stimulation. This paper reviews recent work on the expression of P2X7 receptors in bone, their associated signal transduction mechanisms and roles in regulating bone formation and resorption. Areas for future research in this field are also discussed.
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Kuehnel MP, Reiss M, Anand PK, Treede I, Holzer D, Hoffmann E, Klapperstueck M, Steinberg TH, Markwardt F, Griffiths G. Sphingosine-1-phosphate receptors stimulate macrophage plasma-membrane actin assembly via ADP release, ATP synthesis and P2X7R activation. J Cell Sci 2009; 122:505-12. [PMID: 19174470 DOI: 10.1242/jcs.034207] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Eukaryotic plasma membranes assemble actin filaments within seconds of activation of many receptors, especially during chemotaxis. Here, serum or sphingosine-1-phosphate stimulation of J774 and RAW macrophages released ADP within seconds into the extracellular medium, along with an adenylate kinase activity that converted ADP to ATP. ATP then activated the P2X7 receptor (P2X7R) that was necessary for a peak of plasma-membrane actin assembly within 5 to 10 seconds in P2X7R-expressing J774, RAW and primary macrophages. Neither actin assembly nor characteristic P2X7R channel activity was seen in response to ATP in P2X7R-knockout macrophages, as detected by patch-clamp analysis. Since P2X7R has been shown previously to form a macromolecular complex with actin we propose that it is involved in the membrane assembly of actin. Our data reveal a surprisingly rapid and complex relay of signaling and externalization events that precede and control actin assembly induced by sphingosine-1-phosphate. The overall model we present is strongly supported by the data presented in the accompanying paper that focuses on latex bead phagosomes.
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Pelegrin P, Barroso-Gutierrez C, Surprenant A. P2X7 receptor differentially couples to distinct release pathways for IL-1beta in mouse macrophage. THE JOURNAL OF IMMUNOLOGY 2008; 180:7147-57. [PMID: 18490713 DOI: 10.4049/jimmunol.180.11.7147] [Citation(s) in RCA: 339] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The proinflammatory IL-1 cytokines IL-1alpha, IL-1beta, and IL-18 are key mediators of the acute immune response to injury and infection. Mechanisms underlying their cellular release remain unclear. Activation of purinergic P2X(7) receptors (P2X(7)R) by extracellular ATP is a key physiological inducer of rapid IL-1beta release from LPS-primed macrophage. We investigated patterns of ATP-mediated release of IL-1 cytokines from three macrophage types in attempts to provide direct evidence for or against distinct release mechanisms. We used peritoneal macrophage from P2X(7)R(-/-) mice and found that release of IL-1alpha, IL-18, as well as IL-1beta, by ATP resulted exclusively from activation of P2X(7)R, release of all these IL-1 cytokines involved pannexin-1 (panx1), and that there was both a panx1-dependent and -independent component to IL-1beta release. We compared IL-1-release patterns from LPS-primed peritoneal macrophage, RAW264.7 macrophage, and J774A.1 macrophage. We found RAW264.7 macrophage readily release pro-IL-1beta independently of panx1 but do not release mature IL-1beta because they do not express apoptotic speck-like protein with a caspase-activating recruiting domain and so have no caspase-1 inflammasome activity. We delineated two distinct release pathways: the well-known caspase-1 cascade mediating release of processed IL-1beta that was selectively blocked by inhibition of caspase-1 or panx1, and a calcium-independent, caspase-1/panx1-independent release of pro-IL-1beta that was selectively blocked by glycine. None of these release responses were associated with cell damage or cytolytic effects. This provides the first direct demonstration of a distinct signaling mechanism responsible for ATP-induced release of pro-IL-1beta.
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Affiliation(s)
- Pablo Pelegrin
- Faculty of Life Science, University of Manchester, Manchester, United Kingdom
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Murrell-Lagnado RD, Qureshi OS. Assembly and trafficking of P2X purinergic receptors (Review). Mol Membr Biol 2008; 25:321-31. [PMID: 18446618 DOI: 10.1080/09687680802050385] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
P2X receptors are cation selective ion channels gated by the binding of extracellular ATP. Seven subtypes have been identified and they have widespread and overlapping distributions throughout the body. They form homo- and heterotrimeric complexes that differ in their functional properties and subcellular localization. They form part of larger signalling complexes, interacting with unrelated ion channels and other membrane and cytosolic proteins. Up- or down-regulation of their expression is associated with several disease states. This review aims to summarize recent work on the assembly and trafficking of this family of receptors.
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Supanchart C, Kornak U. Ion channels and transporters in osteoclasts. Arch Biochem Biophys 2008; 473:161-5. [PMID: 18406337 DOI: 10.1016/j.abb.2008.03.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Revised: 03/21/2008] [Accepted: 03/25/2008] [Indexed: 11/27/2022]
Abstract
The resorbing osteoclast is an exceptional cell that secretes large amounts of acid through the coupled activity of a v-type H+-ATPase and a chloride channel that both reside in the ruffled membrane. Impairment of this acid secretion machinery by genetic mutations can abolish bone resorption activity, resulting in osteopetrotic phenotypes. Another key feature of osteoclasts is the transport of high amounts of calcium and phosphate from the resorption lacuna to the basolateral plasma membrane. Evidence exists that this occurs in part through entry of these ions into the osteoclast cytosol. Handling of such large amounts of a cellular messenger requires elaborate mechanisms. Membrane proteins that regulate osteoclast calcium homeostasis and the effect of calcium on osteoclast function and survival are therefore the second main focus of this review.
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Affiliation(s)
- Chayarop Supanchart
- Institut fuer Medizinische Genetik, Charité Universitaetsmedizin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin, Germany
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Ohlendorff SD, Tofteng CL, Jensen JEB, Petersen S, Civitelli R, Fenger M, Abrahamsen B, Hermann AP, Eiken P, Jørgensen NR, Jrgensen NR. Single nucleotide polymorphisms in the P2X7 gene are associated to fracture risk and to effect of estrogen treatment. Pharmacogenet Genomics 2007; 17:555-67. [PMID: 17558311 DOI: 10.1097/fpc.0b013e3280951625] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The purinergic P2RX7 receptor (P2RX7) has been shown to play a role in the regulation of osteoblast and osteoclast activity. The aim of this study was to determine the presence of polymorphisms in exon 13 of the P2X7 gene and the association with osteoclast apoptosis in vitro and bone status in vivo. METHODS A total of 1764 postmenopausal women were genotyped for three single nucleotide polymorphisms detected after sequencing of exon 13 of P2X7. Bone markers, bone mineral density of the hip and lumbar spine were determined at baseline and after 10 years, and vertebral fracture incidence after 10 years. In-vitro ATP-induced caspase-1 determinations were performed on osteoclasts from the different genotypes. RESULTS Three polymorphisms were detected (Gln460Arg, Glu496Ala, and Ile568Asn). None of the polymorphisms was related to bone mineral density or changes in bone mineral density over 10 years in hormone replacement therapy naïve women. The Ile568Asn polymorphism was however, associated with effect of hormone replacement therapy. Furthermore, the 10-year fracture incidence was significantly associated with both the Glu496Ala and the Ile568Asn. The Glu496Ala polymorphism was closely related to ATP-induced osteoclast apoptosis in vitro, as osteoclasts from individuals homozygous for the C allele had significantly decreased apoptotic activity. CONCLUSION The P2X7 Glu496Ala and the Ile568Asn single nucleotide polymorphisms are associated with 10-year fracture risk in postmenopausal women and response to hormone replacement therapy treatment. Further, the Glu496Ala polymorphism is strongly influencing osteoclast apoptosis in vitro, which could contribute to increased fracture risk.
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Affiliation(s)
- Stine D Ohlendorff
- Department of Endocrinology, The Osteoporosis and Metabolic Research Unit, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
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Le Stunff H, Raymond MN. P2X7 receptor-mediated phosphatidic acid production delays ATP-induced pore opening and cytolysis of RAW 264.7 macrophages. Cell Signal 2007; 19:1909-18. [PMID: 17540539 DOI: 10.1016/j.cellsig.2007.04.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 04/30/2007] [Indexed: 12/19/2022]
Abstract
In macrophages, extracellular ATP (ATPe) stimulation of P2X7 receptors (P2X7R) results in cation channel opening, non-specific pore formation, secretion of cytokines, killing of intracellular bacteria and cytolysis. Signaling pathways controlling these diverse responses are currently under investigation. Among these pathways, phospholipase D (PLD) has been implicated in P2X7R-activated macrophages killing of intracellular pathogenic bacteria. Here we present evidence that early P2X7R-mediated PLD activation reduces pore opening and delays cytolysis of RAW 267.4 macrophages induced by ATPe. Use of inhibitors of PA metabolic enzymes suggests that PA, and not one of its metabolites, is the bioactive lipid. This is strengthened by the observation that addition of exogenous PA also reduces pore formation and cytolysis of RAW 264.7 macrophages. However, the beneficial effects of PA are only transient, due to its conversion into diacylglycerol through PA phosphatase-1 activity during prolonged P2X7R stimulation. Revealing that the PLD/PA pathway mediates survival of macrophages provides a potent strategy to inhibit P2X7R-mediated cytolysis by controlling PA metabolism. This will be important in the case of P2X7R-induced killing of intracellular bacteria which is lately associated with macrophage death, limiting the potency of ATPe to eliminate pathogenic bacteria.
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Affiliation(s)
- Hervé Le Stunff
- Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, CNRS UMR 8619, Université Paris Sud, 91405 Orsay cedex, France.
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P2 receptors in macrophage fusion and osteoclast formation. Purinergic Signal 2007; 3:53-7. [PMID: 18404418 PMCID: PMC2096767 DOI: 10.1007/s11302-006-9036-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Accepted: 05/30/2006] [Indexed: 11/05/2022] Open
Abstract
Cells of the mononuclear phagocyte lineage fuse to form multinucleated giant cells and osteoclasts. Several lines of evidence suggest that P2 receptors, in particular P2X7, are involved in this process, although P2X7 is not absolutely required for fusion because P2X7-null mice form multinucleated osteoclasts. Extracellular ATP may be an important regulator of macrophage fusion.
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Lemaire I, Falzoni S, Leduc N, Zhang B, Pellegatti P, Adinolfi E, Chiozzi P, Di Virgilio F. Involvement of the purinergic P2X7 receptor in the formation of multinucleated giant cells. THE JOURNAL OF IMMUNOLOGY 2007; 177:7257-65. [PMID: 17082644 DOI: 10.4049/jimmunol.177.10.7257] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Multinucleated giant cells (MGC), a hallmark of chronic inflammatory reactions, remain an enigma of cell biology. There is evidence implicating the purinergic P2X7 receptor in the fusion process leading to MGC. To investigate this, we used HEK 293 cells stably transfected with either 1) the full-length rat P2X7 receptor (P2X7 cells), 2) a rat P2X7 receptor lacking the C-terminal domain (P2X7TC), or 3) a mock vector, and rat alveolar macrophages (MA) expressing the native receptor. P2X7 cells cultured in serum-free medium formed increased numbers of MGC and displayed a higher fusion index compared with mock transfectants. Stimulation of P2X7 pore-forming activity in P2X7 cells by polymyxin B (PMB) further increased significantly the formation of MGC. Conversely, blockers of P2X-receptors including oxidized ATP, brilliant blue G, and pyridoxal phosphate-6-azophenyl-2'-4'-disulfonic acid inhibited significantly MGC formation in both unstimulated and PMB-stimulated P2X7-transfected cells. In contrast, cells transfected with the truncated P2X7TC were devoid of pore-forming activity, did not respond to PMB stimulation, and failed to form enhanced numbers of MGC, thus behaving as mock transfectants. As found for P2X7-transfected cells, PMB also potentiated dose-dependently the formation of multinucleated MA by rat alveolar MA. Pretreatment with oxidized ATP abrogated the PMB stimulatory effects. Together, these data demonstrate unequivocally the participation of P2X7 receptor in the process of MGC formation. Our study also provides evidence suggesting that stimulation of the P2X7 receptor pathway in MA may mediate increased formation of MGC during chronic inflammatory reactions.
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Affiliation(s)
- Irma Lemaire
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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33
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Mager PP, Illes P. The h-P2X3 glycoprotein receptor as an example of integrating bioinformatics and structural research. Expert Opin Drug Discov 2006; 1:303-9. [DOI: 10.1517/17460441.1.4.303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Li J, Liu D, Ke HZ, Duncan RL, Turner CH. The P2X7 nucleotide receptor mediates skeletal mechanotransduction. J Biol Chem 2005; 280:42952-9. [PMID: 16269410 DOI: 10.1074/jbc.m506415200] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The P2X7 nucleotide receptor (P2X7R) is an ATP-gated ion channel expressed in many cell types including osteoblasts and osteocytes. Mice with a null mutation of P2X7R have osteopenia in load bearing bones, suggesting that the P2X7R may be involved in the skeletal response to mechanical loading. We found the skeletal sensitivity to mechanical loading was reduced by up to 73% in P2X7R null (knock-out (KO)) mice. Release of ATP in the primary calvarial osteoblasts occurred within 1 min of onset of fluid shear stress (FSS). After 30 min of FSS, P2X7R-mediated pore formation was observed in wild type (WT) cells but not in KO cells. FSS increased prostaglandin (PG) E2 release in WT cells but did not alter PGE2 release in KO cells. Studies using MC3T3-E1 osteoblasts and MLO-Y4 osteocytes confirmed that PGE2 release was suppressed by P2X7R blockade, whereas the P2X7R agonist BzATP enhanced PGE2 release. We conclude that ATP signaling through P2X7R is necessary for mechanically induced release of prostaglandins by bone cells and subsequent osteogenesis.
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MESH Headings
- Adenosine Triphosphate/metabolism
- Animals
- Apoptosis
- Blotting, Western
- Bone Diseases, Metabolic/pathology
- Bone Regeneration
- Bone and Bones/metabolism
- Caspase 3
- Caspases/metabolism
- Dinoprostone/metabolism
- Ion Channels/chemistry
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Models, Biological
- Osteoblasts/metabolism
- Osteocytes/metabolism
- Radius/metabolism
- Receptors, Prostaglandin E/metabolism
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2/physiology
- Receptors, Purinergic P2X7
- Signal Transduction
- Stress, Mechanical
- Time Factors
- Ulna/metabolism
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Affiliation(s)
- Jiliang Li
- Department of Anatomy and Cell Biology and Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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Davis PH, Zhang Z, Chen M, Zhang X, Chakraborty S, Stanley SL. Identification of a family of BspA like surface proteins of Entamoeba histolytica with novel leucine rich repeats. Mol Biochem Parasitol 2005; 145:111-6. [PMID: 16199101 PMCID: PMC1382194 DOI: 10.1016/j.molbiopara.2005.08.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 07/26/2005] [Accepted: 08/29/2005] [Indexed: 11/25/2022]
Affiliation(s)
- Paul H Davis
- Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA
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