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Pharmacological activation of lysophosphatidic acid receptors regulates erythropoiesis. Sci Rep 2016; 6:27050. [PMID: 27244685 PMCID: PMC4886675 DOI: 10.1038/srep27050] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/13/2016] [Indexed: 12/11/2022] Open
Abstract
Lysophosphatidic acid (LPA), a growth factor-like phospholipid, regulates numerous physiological functions, including cell proliferation and differentiation. In a previous study, we have demonstrated that LPA activates erythropoiesis by activating the LPA 3 receptor subtype (LPA3) under erythropoietin (EPO) induction. In the present study, we applied a pharmacological approach to further elucidate the functions of LPA receptors during red blood cell (RBC) differentiation. In K562 human erythroleukemia cells, knockdown of LPA2 enhanced erythropoiesis, whereas knockdown of LPA3 inhibited RBC differentiation. In CD34+ human hematopoietic stem cells (hHSC) and K526 cells, the LPA3 agonist 1-oleoyl-2-methyl-sn-glycero-3-phosphothionate (2S-OMPT) promoted erythropoiesis, whereas the LPA2 agonist dodecyl monophosphate (DMP) and the nonlipid specific agonist GRI977143 (GRI) suppressed this process. In zebrafish embryos, hemoglobin expression was significantly increased by 2S-OMPT treatment but was inhibited by GRI. Furthermore, GRI treatment decreased, whereas 2S-OMPT treatment increased RBC counts and amount of hemoglobin level in adult BALB/c mice. These results indicate that LPA2 and LPA3 play opposing roles during RBC differentiation. The pharmacological activation of LPA receptor subtypes represent a novel strategies for augmenting or inhibiting erythropoiesis.
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Liu Y, An S, Ward R, Yang Y, Guo XX, Li W, Xu TR. G protein-coupled receptors as promising cancer targets. Cancer Lett 2016; 376:226-39. [PMID: 27000991 DOI: 10.1016/j.canlet.2016.03.031] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/14/2016] [Accepted: 03/14/2016] [Indexed: 02/07/2023]
Abstract
G protein-coupled receptors (GPCRs) regulate an array of fundamental biological processes, such as growth, metabolism and homeostasis. Specifically, GPCRs are involved in cancer initiation and progression. However, compared with the involvement of the epidermal growth factor receptor in cancer, that of GPCRs have been largely ignored. Recent findings have implicated many GPCRs in tumorigenesis, tumor progression, invasion and metastasis. Moreover, GPCRs contribute to the establishment and maintenance of a microenvironment which is permissive for tumor formation and growth, including effects upon surrounding blood vessels, signaling molecules and the extracellular matrix. Thus, GPCRs are considered to be among the most useful drug targets against many solid cancers. Development of selective ligands targeting GPCRs may provide novel and effective treatment strategies against cancer and some anticancer compounds are now in clinical trials. Here, we focus on tumor related GPCRs, such as G protein-coupled receptor 30, the lysophosphatidic acid receptor, angiotensin receptors 1 and 2, the sphingosine 1-phosphate receptors and gastrin releasing peptide receptor. We also summarize their tissue distributions, activation and roles in tumorigenesis and discuss the potential use of GPCR agonists and antagonists in cancer therapy.
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Affiliation(s)
- Ying Liu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Su An
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Richard Ward
- Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Yang Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Xiao-Xi Guo
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Wei Li
- Kidney Cancer Research, Diagnosis and Translational Technology Center of Yunnan Province, Department of Urology, The People's Hospital of Yunnan Province, Kunming, Yunnan 650032, China.
| | - Tian-Rui Xu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan 650500, China.
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Seo EJ, Kwon YW, Jang IH, Kim DK, Lee SI, Choi EJ, Kim KH, Suh DS, Lee JH, Choi KU, Lee JW, Mok HJ, Kim KP, Matsumoto H, Aoki J, Kim JH. Autotaxin Regulates Maintenance of Ovarian Cancer Stem Cells through Lysophosphatidic Acid-Mediated Autocrine Mechanism. Stem Cells 2016; 34:551-64. [PMID: 26800320 DOI: 10.1002/stem.2279] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 11/04/2015] [Indexed: 12/22/2022]
Abstract
Ovarian cancer shows high mortality due to development of resistance to chemotherapy and relapse. Cancer stem cells (CSCs) have been suggested to be a major contributor in developing drug resistance and relapse in ovarian cancer. In this study, we isolated CSCs through sphere culture of A2780, SKOV3, OVCAR3 epithelial ovarian cancer cells and primary ovarian cancer cells from patients. We identified heat-stable factors secreted from ovarian CSCs stimulated migration and proliferation of CSCs. Mass spectrometry and ELISA analysis revealed that lysophosphatidic acid (LPA) was significantly elevated in CSC culture media compared with non-CSC culture media. Treatment of CSCs with LPA resulted in augmented CSC characteristics such as sphere-forming ability, resistance to anticancer drugs, tumorigenic potential in xenograft transplantation, and high expression of CSC-associated genes, including OCT4, SOX2, and aldehyde dehydrogenase 1. Treatment of CSCs with LPA receptor 1-specific inhibitors or silencing of LPA receptor 1 expression abrogated the LPA-stimulated CSC properties. Autotaxin, an LPA-producing enzyme, is highly secreted from ovarian CSCs, and pharmacological inhibition or knockdown of autotaxin markedly attenuated the LPA-producing, tumorigenic, and drug resistance potentials of CSCs. Clinicopathological analysis showed a significant survival disadvantage of patients with positive staining of autotaxin. In addition, we further identified that AKT1 activity was upregulated in ovarian CSCs through an LPA-dependent mechanism and silencing of AKT1 expression led to suppression of CSC characteristics. These results suggest that autotaxin-LPA-LPA receptor 1-AKT1 signaling axis is critical for maintaining CSC characteristics through an autocrine loop and provide a novel therapeutic target for ovarian CSCs.
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Affiliation(s)
- Eun Jin Seo
- Department of Physiology, Pusan National University, Yangsan, Republic of Korea
| | - Yang Woo Kwon
- Department of Physiology, Pusan National University, Yangsan, Republic of Korea
| | - Il Ho Jang
- Department of Physiology, Pusan National University, Yangsan, Republic of Korea
| | - Dae Kyoung Kim
- Department of Physiology, Pusan National University, Yangsan, Republic of Korea
| | - Soo In Lee
- Department of Physiology, Pusan National University, Yangsan, Republic of Korea
| | - Eun Jung Choi
- Department of Physiology, Pusan National University, Yangsan, Republic of Korea
| | - Ki-Hyung Kim
- Department of Obstetrics and Gynecology, Pusan National University, Yangsan, Republic of Korea
| | - Dong-Soo Suh
- Department of Obstetrics and Gynecology, Pusan National University, Yangsan, Republic of Korea
| | - Jeong Hee Lee
- Department of Pathology, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Kyung Un Choi
- Department of Pathology, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Jae Won Lee
- Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin, Republic of Korea
| | - Hyuck Jun Mok
- Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin, Republic of Korea
| | - Kwang Pyo Kim
- Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin, Republic of Korea
| | - Hirotaka Matsumoto
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Junken Aoki
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Jae Ho Kim
- Department of Physiology, Pusan National University, Yangsan, Republic of Korea.,Research Institute of Convergence Biomedical Science and Technology, Pusan National University, Yangsan Hospital, Yangsan, Republic of Korea
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Wang XY, Fan XS, Cai L, Liu S, Cong XF, Chen X. Lysophosphatidic acid rescues bone mesenchymal stem cells from hydrogen peroxide-induced apoptosis. Apoptosis 2015; 20:273-84. [PMID: 25633408 DOI: 10.1007/s10495-014-1074-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The increase of reactive oxygen species in infracted heart significantly reduces the survival of donor mesenchymal stem cells, thereby attenuating the therapeutic efficacy for myocardial infarction. In our previous study, we demonstrated that lysophosphatidic acid (LPA) protects bone marrow-derived mesenchymal stem cells (BMSCs) against hypoxia and serum deprivation-induced apoptosis. However, whether LPA protects BMSCs from H2O2-induced apoptosis was not examined. In this study, we report that H2O2 induces rat BMSC apoptosis whereas LPA pre-treatment effectively protects BMSCs from H2O2-induced apoptosis. LPA protection of BMSC from the induced apoptosis is mediated mostly through LPA3 receptor. Furthermore, we found that membrane G protein Gi2 and Gi3 are involved in LPA-elicited anti-apoptotic effects through activation of ERK1/2- and PI3 K-pathways. Additionally, H2O2 increases levels of type II of light chain 3B (LC3B II), an autophagy marker, and H2O2-induced autophagy thus protected BMSCs from apoptosis. LPA further increases the expression of LC3B II in the presence of H2O2. In contrast, autophagy flux inhibitor bafilomycin A1 has no effect on LPA's protection of BMSC from H2O2-induced apoptosis. Taken together, our data suggest that LPA rescues H2O2-induced apoptosis mainly by interacting with Gi-coupled LPA3, resulting activation of the ERK1/2- and PI3 K/AKT-pathways and inhibition caspase-3 cleavage, and LPA protection of BMSCs against the apoptosis is independent of it induced autophagy.
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Affiliation(s)
- Xian-Yun Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Centre for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
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Biased signalling: the instinctive skill of the cell in the selection of appropriate signalling pathways. Biochem J 2015; 470:155-67. [DOI: 10.1042/bj20150358] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
GPCRs (G-protein-coupled receptors) are members of a family of proteins which are generally regarded as the largest group of therapeutic drug targets. Ligands of GPCRs do not usually activate all cellular signalling pathways linked to a particular seven-transmembrane receptor in a uniform manner. The fundamental idea behind this concept is that each ligand has its own ability, while interacting with the receptor, to activate different signalling pathways (or a particular set of signalling pathways) and it is this concept which is known as biased signalling. The importance of biased signalling is that it may selectively activate biological responses to favour therapeutically beneficial signalling pathways and to avoid adverse effects. There are two levels of biased signalling. First, bias can arise from the ability of GPCRs to couple to a subset of the available G-protein subtypes: Gαs, Gαq/11, Gαi/o or Gα12/13. These subtypes produce the diverse effects of GPCRs by targeting different effectors. Secondly, biased GPCRs may differentially activate G-proteins or β-arrestins. β-Arrestins are ubiquitously expressed and function to terminate or inhibit classic G-protein signalling and initiate distinct β-arrestin-mediated signalling processes. The interplay of G-protein and β-arrestin signalling largely determines the cellular consequences of the administration of GPCR-targeted drugs. In the present review, we highlight the particular functionalities of biased signalling and discuss its biological effects subsequent to GPCR activation. We consider that biased signalling is potentially allowing a choice between signalling through ‘beneficial’ pathways and the avoidance of ‘harmful’ ones.
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Kawashima Y, Kushida N, Kokubun S, Ogawa S, Shiomi H, Ishibashi K, Aikawa K, Ikegami K, Nomiya M, Yamaguchi O. Possible effect of lysophosphatidic acid on cell proliferation and involvement of lysophosphatidic acid and lysophosphatidic acid receptors in mechanical stretch-induced mitogen-activated protein kinase. Int J Urol 2015; 22:778-84. [DOI: 10.1111/iju.12799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 03/26/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Yohei Kawashima
- Department of Urology; Fukushima Medical University School of Medicine; Fukushima Japan
| | - Nobuhiro Kushida
- Department of Urology; Fukushima Medical University School of Medicine; Fukushima Japan
| | - Shuko Kokubun
- Department of Urology; Fukushima Medical University School of Medicine; Fukushima Japan
| | - Soichiro Ogawa
- Department of Urology; Fukushima Medical University School of Medicine; Fukushima Japan
| | - Homare Shiomi
- Department of Urology; Fukushima Medical University School of Medicine; Fukushima Japan
| | - Kei Ishibashi
- Department of Urology; Fukushima Medical University School of Medicine; Fukushima Japan
| | - Ken Aikawa
- Department of Urology; Fukushima Medical University School of Medicine; Fukushima Japan
| | - Kentaro Ikegami
- Division of Bioengineering and LUTD Research; Nihon University College of Engineering; Koriyama Japan
| | - Masanori Nomiya
- Division of Bioengineering and LUTD Research; Nihon University College of Engineering; Koriyama Japan
| | - Osamu Yamaguchi
- Division of Bioengineering and LUTD Research; Nihon University College of Engineering; Koriyama Japan
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Fukushima N, Ishii S, Tsujiuchi T, Kagawa N, Katoh K. Comparative analyses of lysophosphatidic acid receptor-mediated signaling. Cell Mol Life Sci 2015; 72:2377-94. [PMID: 25732591 PMCID: PMC11113652 DOI: 10.1007/s00018-015-1872-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/16/2015] [Accepted: 02/23/2015] [Indexed: 12/14/2022]
Abstract
Lysophosphatidic acid (LPA) is a bioactive lipid mediator that activates G protein-coupled LPA receptors to exert fundamental cellular functions. Six LPA receptor genes have been identified in vertebrates and are classified into two subfamilies, the endothelial differentiation genes (edg) and the non-edg family. Studies using genetically engineered mice, frogs, and zebrafish have demonstrated that LPA receptor-mediated signaling has biological, developmental, and pathophysiological functions. Computational analyses have also identified several amino acids (aa) critical for LPA recognition by human LPA receptors. This review focuses on the evolutionary aspects of LPA receptor-mediated signaling by comparing the aa sequences of vertebrate LPA receptors and LPA-producing enzymes; it also summarizes the LPA receptor-dependent effects commonly observed in mouse, frog, and fish.
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Affiliation(s)
- Nobuyuki Fukushima
- Division of Molecular Neurobiology, Department of Life Science, Kinki University, Higashiosaka, 577-8502 Japan
| | - Shoichi Ishii
- Division of Molecular Neurobiology, Department of Life Science, Kinki University, Higashiosaka, 577-8502 Japan
| | - Toshifumi Tsujiuchi
- Division of Cancer Biology and Bioinformatics, Department of Life Science, Kinki University, Higashiosaka, Japan
| | - Nao Kagawa
- Division of Animal Genetics, Department of Life Science, Kinki University, Higashiosaka, Japan
| | - Kazutaka Katoh
- Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871 Japan
- Computational Biology Research Center, The National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
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58
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Zhao C, Sardella A, Davis L, Poubelle PE, Bourgoin SG, Fernandes MJ. A transgenic mouse model for the in vivo bioluminescence imaging of the expression of the lysophosphatidic acid receptor 3: relevance for inflammation and uterine physiology research. Transgenic Res 2015; 24:625-34. [PMID: 25982332 DOI: 10.1007/s11248-015-9882-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 05/02/2015] [Indexed: 01/08/2023]
Abstract
Lysophosphatidic acid (LPA) is a lipid-derived signaling molecule that plays key roles in diverse biological processes including inflammation and uterine remodeling. Although the function of LPA and its receptors has been extensively studied using knock-out mice, the temporal-spatial expression of LPA receptors is less well-characterized. To gain further insight into the dynamic regulation of LPA receptor 3 (Lpar3) expression in vivo by bioluminescence imaging, we generated and characterized mice transgenic for a putative Lpar3 promoter fragment. A non-coding region of the Lpar3 gene immediately upstream of the start site was subcloned adjacent to the luciferase gene. Promoter activity was determined by in vitro luciferase assays, in vivo bioluminescent imaging or by semi-quantitative real-time PCR. The air-pouch model was used to investigate Lpar3 promoter activity in the context of inflammation. The putative Lpar3 promoter fragment behaved similarly to the endogenous promoter in vitro and in vivo. In male mice, elevated levels of Lpar3-induced luciferase activity were observed in the testis. In female mice, the basal level of luciferase activity in the uterus significantly increased during pseudopregnancy. Moreover, luciferase activity was upregulated by TNF-α in the air-pouch model. We report the identification of a functional Lpar3 promoter fragment and the generation of a transgenic mouse model to investigate the regulation of Lpar3 promoter activity non-invasively in vivo by bioluminescence imaging. This mouse model is a valuable tool for reproductive biology and inflammation research as well as other biological processes in which this receptor is involved.
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Affiliation(s)
- Chenqi Zhao
- Rheumatology and Immunology Research Center, Local T1-49, CHUQ-CHUL Research Center and Faculty of Medicine, Laval University, 2705, Boul. Laurier, Québec, QC, G1V 4G2, Canada
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59
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González de San Román E, Manuel I, Giralt MT, Chun J, Estivill-Torrús G, Rodríguez de Fonseca F, Santín LJ, Ferrer I, Rodríguez-Puertas R. Anatomical location of LPA1 activation and LPA phospholipid precursors in rodent and human brain. J Neurochem 2015; 134:471-85. [PMID: 25857358 DOI: 10.1111/jnc.13112] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/02/2015] [Accepted: 03/31/2015] [Indexed: 12/29/2022]
Abstract
Lysophosphatidic acid (LPA) is a signaling molecule that binds to six known G protein-coupled receptors: LPA1 -LPA6 . LPA evokes several responses in the CNS, including cortical development and folding, growth of the axonal cone and its retraction process. Those cell processes involve survival, migration, adhesion proliferation, differentiation, and myelination. The anatomical localization of LPA1 is incompletely understood, particularly with regard to LPA binding. Therefore, we have used functional [(35) S]GTPγS autoradiography to verify the anatomical distribution of LPA1 binding sites in adult rodent and human brain. The greatest activity was observed in myelinated areas of the white matter such as corpus callosum, internal capsule and cerebellum. MaLPA1 -null mice (a variant of LPA1 -null) lack [(35) S]GTPγS basal binding in white matter areas, where the LPA1 receptor is expressed at high levels, suggesting a relevant role of the activity of this receptor in the most myelinated brain areas. In addition, phospholipid precursors of LPA were localized by MALDI-IMS in both rodent and human brain slices identifying numerous species of phosphatides and phosphatidylcholines. Both phosphatides and phosphatidylcholines species represent potential LPA precursors. The anatomical distribution of these precursors in rodent and human brain may indicate a metabolic relationship between LPA and LPA1 receptors. Lysophosphatidic acid (LPA) is a signaling molecule that binds to six known G protein-coupled receptors (GPCR), LPA1 to LPA6 . LPA evokes several responses in the central nervous system (CNS), including cortical development and folding, growth of the axonal cone and its retraction process. We used functional [(35) S]GTPγS autoradiography to verify the anatomical distribution of LPA1 -binding sites in adult rodent and human brain. The distribution of LPA1 receptors in rat, mouse and human brains show the highest activity in white matter myelinated areas. The basal and LPA-evoked activities are abolished in MaLPA1 -null mice. The phospholipid precursors of LPA are localized by MALDI-IMS. The anatomical distribution of LPA precursors in rodent and human brain suggests a relationship with functional LPA1 receptors.
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Affiliation(s)
| | - Iván Manuel
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - María Teresa Giralt
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Jerold Chun
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California, USA
| | - Guillermo Estivill-Torrús
- UGC Intercentros de Neurociencias y UGC de Salud Mental, Instituto de Investigación Biomédica de Malaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, Universidad de Málaga, Spain
| | - Fernando Rodríguez de Fonseca
- UGC Intercentros de Neurociencias y UGC de Salud Mental, Instituto de Investigación Biomédica de Malaga (IBIMA), Hospitales Universitarios Regional de Málaga y Virgen de la Victoria, Universidad de Málaga, Spain
| | - Luis Javier Santín
- Departmento de Psicobiología y Metodología de las Ciencias del Comportamiento. Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad of Málaga, Málaga, Spain
| | - Isidro Ferrer
- Institute of Neuropathology, University Hospital Bellvitge, University of Barcelona, Ciberned, Spain
| | - Rafael Rodríguez-Puertas
- Department of Pharmacology, Faculty of Medicine and Odontology, University of the Basque Country, UPV/EHU, Leioa, Spain
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Wang C, Wang M, Han X. Comprehensive and quantitative analysis of lysophospholipid molecular species present in obese mouse liver by shotgun lipidomics. Anal Chem 2015; 87:4879-87. [PMID: 25860968 DOI: 10.1021/acs.analchem.5b00410] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Shotgun lipidomics exploits the unique chemical and physical properties of lipid classes and individual molecular species to facilitate the high-throughput analysis of a cellular lipidome on a large scale directly from the extracts of biological samples. A platform for comprehensive analysis of lysophospholipid (LPL) species based on shotgun lipidomics has not been established. Herein, after extensive characterization of the fragmentation pattern of individual LPL class and optimization of all experimental conditions including developing new methods for optimization of collision energy, and recovery and enrichment of LPL classes from the aqueous phase after solvent extraction, a new method for comprehensive and quantitative analysis of LPL species was developed. This newly developed method was applied for comprehensive analysis of LPL species present in mouse liver samples. Remarkably, the study revealed significant accumulation of LPL species in the liver of ob/ob mice. Taken together, by exploiting the principles of shotgun lipidomics in combination with a novel strategy of sample preparation, LPL species present in biological samples can be determined by the established method. We believe that this development is significant and useful for understanding the pathways of phospholipid metabolism and for elucidating the role of LPL species in signal transduction and other biological functions.
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Affiliation(s)
- Chunyan Wang
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, Florida 32827, United States
| | - Miao Wang
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, Florida 32827, United States
| | - Xianlin Han
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, Florida 32827, United States
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61
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Llona-Minguez S, Ghassemian A, Helleday T. Lysophosphatidic acid receptor (LPAR) modulators: The current pharmacological toolbox. Prog Lipid Res 2015; 58:51-75. [DOI: 10.1016/j.plipres.2015.01.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 01/15/2015] [Accepted: 01/20/2015] [Indexed: 12/17/2022]
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62
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RHOA inactivation enhances Wnt signalling and promotes colorectal cancer. Nat Commun 2014; 5:5458. [PMID: 25413277 PMCID: PMC4255233 DOI: 10.1038/ncomms6458] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 10/02/2014] [Indexed: 12/23/2022] Open
Abstract
Activation of the small GTPase RHOA has strong oncogenic effects in many tumour types, although its role in colorectal cancer remains unclear. Here we show that RHOA inactivation contributes to colorectal cancer progression/metastasis, largely through the activation of Wnt/β-catenin signalling. RhoA inactivation in the murine intestine accelerates the tumorigenic process and in human colon cancer cells leads to the redistribution of β-catenin from the membrane to the nucleus and enhanced Wnt/β-catenin signalling, resulting in increased proliferation, invasion and de-differentiation. In mice, RHOA inactivation contributes to colon cancer metastasis and reduced RHOA levels were observed at metastatic sites compared with primary human colon tumours. Therefore, we have identified a new mechanism of activation of Wnt/β-catenin signalling and characterized the role of RHOA as a novel tumour suppressor in colorectal cancer. These results constitute a shift from the current paradigm and demonstrate that RHO GTPases can suppress tumour progression and metastasis.
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63
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Morimoto Y, Ishii S, Ishibashi JI, Katoh K, Tsujiuchi T, Kagawa N, Fukushima N. Functional lysophosphatidic acid receptors expressed in Oryzias latipes. Gene 2014; 551:189-200. [PMID: 25173740 DOI: 10.1016/j.gene.2014.08.056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 08/11/2014] [Accepted: 08/27/2014] [Indexed: 10/24/2022]
Abstract
Lysophosphatidic acid (LPA) signaling is known to play biological and pathophysiological roles in many types of animals. Medaka (Oryzias latipes) is an experimental fish that can be easily maintained, propagated, and analyzed, and whose genome has been completely sequenced. However, there is limited information available regarding medaka LPA receptors. Here, using information from the medaka genome database, we examine the genomic structures, expression, and functions of six LPA receptor genes, Lpar1-Lpar6. Our analyses reveal that the genomic structures of Lpar1 and Lpar4 are different from those deduced from the database. Functional analyses using a heterologous expression system demonstrate that all medaka LPA receptors except for LPA5b respond to LPA treatment with cytoskeletal changes. These findings provide useful information on the structure and function of medaka LPA receptor genes, and identify medaka as a useful experimental model for exploration of the biological significance of LPA signaling.
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Affiliation(s)
- Yuji Morimoto
- Division of Molecular Neurobiology, Department of Life Science, Kinki University, Higashiosaka, Japan
| | - Shoichi Ishii
- Division of Molecular Neurobiology, Department of Life Science, Kinki University, Higashiosaka, Japan
| | - Jun-Ichi Ishibashi
- Division of Molecular Neurobiology, Department of Life Science, Kinki University, Higashiosaka, Japan
| | - Kazutaka Katoh
- Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan; Computational Biology Research Center, The National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Toshifumi Tsujiuchi
- Division of Cancer Biology and Bioinformatics, Department of Life Science, Kinki University, Higashiosaka, Japan
| | - Nao Kagawa
- Division of Animal Genetics, Department of Life Science, Kinki University, Higashiosaka, Japan
| | - Nobuyuki Fukushima
- Division of Molecular Neurobiology, Department of Life Science, Kinki University, Higashiosaka, Japan.
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64
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Kihara Y, Maceyka M, Spiegel S, Chun J. Lysophospholipid receptor nomenclature review: IUPHAR Review 8. Br J Pharmacol 2014; 171:3575-94. [PMID: 24602016 PMCID: PMC4128058 DOI: 10.1111/bph.12678] [Citation(s) in RCA: 253] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/03/2014] [Accepted: 02/12/2014] [Indexed: 12/11/2022] Open
Abstract
Lysophospholipids encompass a diverse range of small, membrane-derived phospholipids that act as extracellular signals. The signalling properties are mediated by 7-transmembrane GPCRs, constituent members of which have continued to be identified after their initial discovery in the mid-1990s. Here we briefly review this class of receptors, with a particular emphasis on their protein and gene nomenclatures that reflect their cognate ligands. There are six lysophospholipid receptors that interact with lysophosphatidic acid (LPA): protein names LPA1 - LPA6 and italicized gene names LPAR1-LPAR6 (human) and Lpar1-Lpar6 (non-human). There are five sphingosine 1-phosphate (S1P) receptors: protein names S1P1 -S1P5 and italicized gene names S1PR1-S1PR5 (human) and S1pr1-S1pr5 (non-human). Recent additions to the lysophospholipid receptor family have resulted in the proposed names for a lysophosphatidyl inositol (LPI) receptor - protein name LPI1 and gene name LPIR1 (human) and Lpir1 (non-human) - and three lysophosphatidyl serine receptors - protein names LyPS1 , LyPS2 , LyPS3 and gene names LYPSR1-LYPSR3 (human) and Lypsr1-Lypsr3 (non-human) along with a variant form that does not appear to exist in humans that is provisionally named LyPS2L . This nomenclature incorporates previous recommendations from the International Union of Basic and Clinical Pharmacology, the Human Genome Organization, the Gene Nomenclature Committee, and the Mouse Genome Informatix.
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Affiliation(s)
- Yasuyuki Kihara
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research InstituteLa Jolla, CA, USA
| | - Michael Maceyka
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, School of Medicine, Virginia Commonwealth UniversityRichmond, VA, USA
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, School of Medicine, Virginia Commonwealth UniversityRichmond, VA, USA
| | - Jerold Chun
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research InstituteLa Jolla, CA, USA
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Zhao J, Wei J, Bowser RK, Dong S, Xiao S, Zhao Y. Molecular regulation of lysophosphatidic acid receptor 1 trafficking to the cell surface. Cell Signal 2014; 26:2406-11. [PMID: 25025571 DOI: 10.1016/j.cellsig.2014.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/09/2014] [Indexed: 01/20/2023]
Abstract
The lysophosphatidic acid receptor 1 (LPA1), a G-protein coupled receptor, regulates cell proliferation, migration, and cytokine release. Here, we investigate the molecular signature of LPA1 trafficking to the cell surface. The overexpressed LPA1 with a C-terminal V5 tag (LPA1-V5) is majorly expressed on the cell surface, while two deletion mutants (C320 and ∆84-87) failed to be trafficked to the cell surface. Further, site-directed mutagenesis analysis of the LPA1 revealed that Ile325, Tyr85, and Leu87 within these two fragments regulate LPA1 maturation and trafficking to the cell surface. Over-expression of Sar1, a component of coat protein complex II (COPII), enhances glycosylation of LPA1 wild type, but not these mutants. The mutants of LPA1 are majorly localized in the endoplasmic reticulum (ER) and exhibit a higher binding affinity to heat shock protein 70 (Hsp70), when compared to the LPA1 wild type. Further, we found that all these mutants failed to increase phosphorylation of Erk, and the cytokine release in response to LPA treatment. These results suggest that Ile325, Tyr85, and Leu87 within LPA1 are essential for LPA1 protein properly folding in the ER.
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Affiliation(s)
- Jing Zhao
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jianxin Wei
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Rachel K Bowser
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Su Dong
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States; Department of Anesthesia, First Hospital of Jilin University, Changchun, China
| | - Shuqi Xiao
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States
| | - Yutong Zhao
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Vascular and Medical Institute, University of Pittsburgh, Pittsburgh, PA, United States.
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Kuriyama S, Theveneau E, Benedetto A, Parsons M, Tanaka M, Charras G, Kabla A, Mayor R. In vivo collective cell migration requires an LPAR2-dependent increase in tissue fluidity. J Cell Biol 2014; 206:113-27. [PMID: 25002680 PMCID: PMC4085712 DOI: 10.1083/jcb.201402093] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 06/02/2014] [Indexed: 11/22/2022] Open
Abstract
Collective cell migration (CCM) and epithelial-mesenchymal transition (EMT) are common to cancer and morphogenesis, and are often considered to be mutually exclusive in spite of the fact that many cancer and embryonic cells that have gone through EMT still cooperate to migrate collectively. Here we use neural crest (NC) cells to address the question of how cells that have down-regulated cell-cell adhesions can migrate collectively. NC cell dissociation relies on a qualitative and quantitative change of the cadherin repertoire. We found that the level of cell-cell adhesion is precisely regulated by internalization of N-cadherin downstream of lysophosphatidic acid (LPA) receptor 2. Rather than promoting the generation of single, fully mesenchymal cells, this reduction of membrane N-cadherin only triggers a partial mesenchymal phenotype. This intermediate phenotype is characterized by an increase in tissue fluidity akin to a solid-like-to-fluid-like transition. This change of plasticity allows cells to migrate under physical constraints without abolishing cell cooperation required for collectiveness.
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Affiliation(s)
- Sei Kuriyama
- Cell and Developmental Biology Department, University College London, London WC1E 6BT, England, UK Department of Molecular Medicine and Biochemistry, Akita University Graduate School of Medicine and Faculty of Medicine, Akita City, Akita 010-8543, Japan
| | - Eric Theveneau
- Cell and Developmental Biology Department, University College London, London WC1E 6BT, England, UK
| | - Alexandre Benedetto
- London Centre for Nanotechnology, University College London, London WC1H 0AH, England, UK
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, Kings College London, London SE11UL, England, UK
| | - Masamitsu Tanaka
- Department of Molecular Medicine and Biochemistry, Akita University Graduate School of Medicine and Faculty of Medicine, Akita City, Akita 010-8543, Japan
| | - Guillaume Charras
- Cell and Developmental Biology Department, University College London, London WC1E 6BT, England, UK London Centre for Nanotechnology, University College London, London WC1H 0AH, England, UK
| | - Alexandre Kabla
- Engineering Department, Mechanics and Materials Division, Cambridge University, Cambridge CB2 1PZ, England, UK
| | - Roberto Mayor
- Cell and Developmental Biology Department, University College London, London WC1E 6BT, England, UK
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Tiftik RN, Başkurt OK, Kul S, Büyükafşar K. The functional significance of the rho/rho-kinase pathway in human erythrocytes. Turk J Haematol 2014; 31:168-74. [PMID: 25035675 PMCID: PMC4102045 DOI: 10.4274/tjh.2013.0115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 07/19/2013] [Indexed: 01/16/2023] Open
Abstract
Objective: Erythrocyte deformability, which can be influenced by various intracellular signaling mechanisms, such as nitric oxide, cAMP, cGMP, and protein kinases, is the most important physiological factor providing the blood flow in microcirculation. However, the functional significance of the Rho/Rho-kinase pathway, which contributes cell shape changes and the reorganization of the actin cytoskeleton, has yet to be explored in erythrocytes. Therefore, we examined the influence of several activators and inhibitors of Rho/Rho-kinase signaling on human erythrocyte deformability. Materials and Methods: RhoA and ROCK-2 proteins were studied by western blotting. Influences of 2 Rho-kinase inhibitors, fasudil and Y-27632 (both 10-7 to 10-4 M), on erythrocyte deformability was determined by ektacytometer at various shear stresses (0-30 Pa) in the presence or absence of a known Rho activator, lysophosphatidic acid (LPA, 10-5 to 5x10-5 M, 1-15 min). Results: LPA incubation reduced deformability with concomitant RhoA-GTP inhibition. Y-27632 and fasudil also decreased deformability, but had no effect on LPA-induced reduction of deformability. Rho inhibitor C3 had no effect on RhoA activation. Reduction in RhoA activation was induced by sub-hemolytic mechanical stress. Conclusion: Our findings may indicate that the Rho/Rho-kinase pathway could contribute to the regulation of deformability of human erythrocytes.
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Affiliation(s)
- R Nalan Tiftik
- Mersin University Faculty of Medicine, Department of Pharmacology, Mersin, Turkey
| | | | - Seval Kul
- Gaziantep University Faculty of Medicine, Department of Biostatistics, Gaziantep, Turkey
| | - Kansu Büyükafşar
- Mersin University Faculty of Medicine, Department of Pharmacology, Mersin, Turkey
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68
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Araki M, Kitayoshi M, Dong Y, Hirane M, Ozaki S, Mori S, Fukushima N, Honoki K, Tsujiuchi T. Inhibitory effects of lysophosphatidic acid receptor-5 on cellular functions of sarcoma cells. Growth Factors 2014; 32:117-22. [PMID: 24798396 DOI: 10.3109/08977194.2014.911294] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lysophosphatidic acid (LPA) is a bioactive lipid that interacts with G protein-coupled LPA receptors (LPA receptor-1 (LPA1) to LPA6). Here, we investigated the effects of LPA signaling via LPA5 on cellular functions of sarcoma cells by generating Lpar5 overexpressing and Lpar5 knockdown cells from rat osteosarcoma and malignant fibrous histiocytoma cells, respectively. The cell motility activity of Lpar5 overexpressing cells was significantly lower, while Lpar5 knockdown cells showed high cell motility, compared with respective controls. Gelatin zymography showed that LPA5 suppressed the activation of matrix metalloproteinase-2. LPA5 also inhibited the cell motility activity of endothelial cells, correlating with the expression levels of vascular endothelial growth factor genes. These results suggest that LPA signaling via LPA5 negatively regulates the cellular functions of rat sarcoma cells.
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69
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Enrichment of phosphatidylinositols with specific acyl chains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1501-8. [DOI: 10.1016/j.bbamem.2013.10.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 09/25/2013] [Accepted: 10/03/2013] [Indexed: 12/21/2022]
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Tsou PS, Haak AJ, Khanna D, Neubig RR. Cellular mechanisms of tissue fibrosis. 8. Current and future drug targets in fibrosis: focus on Rho GTPase-regulated gene transcription. Am J Physiol Cell Physiol 2014; 307:C2-13. [PMID: 24740541 DOI: 10.1152/ajpcell.00060.2014] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tissue fibrosis occurs with excessive extracellular matrix deposition from myofibroblasts, resulting in tissue scarring and inflammation. It is driven by multiple mediators, such as the G protein-coupled receptor ligands lysophosphatidic acid and endothelin, as well as signaling by transforming growth factor-β, connective tissue growth factor, and integrins. Fibrosis contributes to 45% of deaths in the developed world. As current therapeutic options for tissue fibrosis are limited and organ transplantation is the only effective treatment for end-stage disease, there is an imminent need for efficacious antifibrotic therapies. This review discusses the various molecular pathways involved in fibrosis. It highlights the Rho GTPase signaling pathway and its downstream gene transcription output through myocardin-related transcription factor and serum response factor as a convergence point for targeting this complex set of diseases.
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Affiliation(s)
- Pei-Suen Tsou
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Scleroderma Program, Ann Arbor, Michigan
| | - Andrew J Haak
- Department of Pharmacology, University of Michigan Medical Center, Ann Arbor, Michigan; and
| | - Dinesh Khanna
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Scleroderma Program, Ann Arbor, Michigan
| | - Richard R Neubig
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
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Yung YC, Stoddard NC, Chun J. LPA receptor signaling: pharmacology, physiology, and pathophysiology. J Lipid Res 2014; 55:1192-214. [PMID: 24643338 DOI: 10.1194/jlr.r046458] [Citation(s) in RCA: 523] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Indexed: 12/18/2022] Open
Abstract
Lysophosphatidic acid (LPA) is a small ubiquitous lipid found in vertebrate and nonvertebrate organisms that mediates diverse biological actions and demonstrates medicinal relevance. LPA's functional roles are driven by extracellular signaling through at least six 7-transmembrane G protein-coupled receptors. These receptors are named LPA1-6 and signal through numerous effector pathways activated by heterotrimeric G proteins, including Gi/o, G12/13, Gq, and Gs LPA receptor-mediated effects have been described in numerous cell types and model systems, both in vitro and in vivo, through gain- and loss-of-function studies. These studies have revealed physiological and pathophysiological influences on virtually every organ system and developmental stage of an organism. These include the nervous, cardiovascular, reproductive, and pulmonary systems. Disturbances in normal LPA signaling may contribute to a range of diseases, including neurodevelopmental and neuropsychiatric disorders, pain, cardiovascular disease, bone disorders, fibrosis, cancer, infertility, and obesity. These studies underscore the potential of LPA receptor subtypes and related signaling mechanisms to provide novel therapeutic targets.
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Affiliation(s)
- Yun C Yung
- Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037
| | - Nicole C Stoddard
- Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037 Biomedical Sciences Graduate Program, University of California, San Diego School of Medicine, La Jolla, CA 92037
| | - Jerold Chun
- Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA 92037
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Daino K, Imaoka T, Morioka T, Tani S, Iizuka D, Nishimura M, Shimada Y. Loss of the BRCA1-interacting helicase BRIP1 results in abnormal mammary acinar morphogenesis. PLoS One 2013; 8:e74013. [PMID: 24040146 PMCID: PMC3765252 DOI: 10.1371/journal.pone.0074013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 07/25/2013] [Indexed: 11/19/2022] Open
Abstract
BRIP1 is a DNA helicase that directly interacts with the C-terminal BRCT repeat of the breast cancer susceptibility protein BRCA1 and plays an important role in BRCA1-dependent DNA repair and DNA damage-induced checkpoint control. Recent studies implicate BRIP1 as a moderate/low-penetrance breast cancer susceptibility gene. However, the phenotypic effects of BRIP1 dysfunction and its role in breast cancer tumorigenesis remain unclear. To explore the function of BRIP1 in acinar morphogenesis of mammary epithelial cells, we generated BRIP1-knockdown MCF-10A cells by short hairpin RNA (shRNA)-mediated RNA interference and examined its effect in a three-dimensional culture model. Genome-wide gene expression profiling by microarray and quantitative RT-PCR were performed to identify alterations in gene expression in BRIP1-knockdown cells compared with control cells. The microarray data were further investigated using the pathway analysis and Gene Set Enrichment Analysis (GSEA) for pathway identification. BRIP1 knockdown in non-malignant MCF-10A mammary epithelial cells by RNA interference induced neoplastic-like changes such as abnormal cell adhesion, increased cell proliferation, large and irregular-shaped acini, invasive growth, and defective lumen formation. Differentially expressed genes, including MCAM, COL8A1, WIPF1, RICH2, PCSK5, GAS1, SATB1, and ELF3, in BRIP1-knockdown cells compared with control cells were categorized into several functional groups, such as cell adhesion, polarity, growth, signal transduction, and developmental process. Signaling-pathway analyses showed dysregulation of multiple cellular signaling pathways, involving LPA receptor, Myc, Wnt, PI3K, PTEN as well as DNA damage response, in BRIP1-knockdown cells. Loss of BRIP1 thus disrupts normal mammary morphogenesis and causes neoplastic-like changes, possibly via dysregulating multiple cellular signaling pathways functioning in the normal development of mammary glands.
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Affiliation(s)
- Kazuhiro Daino
- Radiobiology for Children’s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan
- Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, Chiba, Japan
- * E-mail: (KD); (YS)
| | - Tatsuhiko Imaoka
- Radiobiology for Children’s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan
- Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, Chiba, Japan
| | - Takamitsu Morioka
- Radiobiology for Children’s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan
- Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, Chiba, Japan
| | - Shusuke Tani
- Radiobiology for Children’s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan
| | - Daisuke Iizuka
- Radiobiology for Children’s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan
- Department of Experimental Oncology, Division of Genome Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Mayumi Nishimura
- Radiobiology for Children’s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan
- Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, Chiba, Japan
| | - Yoshiya Shimada
- Radiobiology for Children’s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan
- Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, Chiba, Japan
- * E-mail: (KD); (YS)
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Tanabe E, Kitayoshi M, Hirane M, Araki M, Dong Y, Fukushima N, Tsujiuchi T. Downregulation of activation factors of endothelia and fibroblasts via lysophosphatidic acid signaling in a mouse lung cancer LL/2 cell line. J Recept Signal Transduct Res 2013; 33:286-90. [PMID: 23909436 DOI: 10.3109/10799893.2013.823998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Angiogenesis stimulates the invasive and metastatic process of cancer cells. It is also known that activated fibroblasts promote cancer cell growth and enhance invasive and metastatic potential. Lysophosphatidic acid (LPA) is a biological mediator and interacts with G protein-coupled transmembrane LPA receptors (LPA1 to LPA6). In this study, to assess an involvement of LPA3 on angiogenesis and fibroblast activation, the Lpar3-expressing cells were generated from mouse lung cancer LL/2 cells, which unexpressed LPA3. The Lpar3-expressing cells were maintained in serum-free Dulbecco's modified Eagle's medium for 48 h, and cell motility assay was performed with a cell culture Insert. When endothelial F-2 cells and 3T3 fibroblasts were cultured with conditioned medium from the Lpar3-expressing cells, their cell motile activities were significantly lower than the Lpar3-unexpressing (control) cells. Expression levels of vascular endothelial growth factor (Vegf) and fibroblast growth factor (Fgf) genes in the Lpar3-expressing cells were measured by quantitative real time reverse transcription polymerase chain reaction analysis. The expressions of Vegf-A. Fgfa and Fgfb genes in the Lpar3-expressing cells were significantly lower than those in control cells, correlating with the effects on cell motile activities of F-2 and 3T3 cells. These results suggest that LPA signaling through LPA3 may inhibit angiogenesis and fibroblast activation in mouse lung cancer cells.
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Affiliation(s)
- Eriko Tanabe
- Division of Cancer Biology and Bioinformatics and
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Pedraza C, Sánchez-López J, Castilla-Ortega E, Rosell-Valle C, Zambrana-Infantes E, García-Fernández M, Rodriguez de Fonseca F, Chun J, Santín LJ, Estivill-Torrús G. Fear extinction and acute stress reactivity reveal a role of LPA(1) receptor in regulating emotional-like behaviors. Brain Struct Funct 2013; 219:1659-72. [PMID: 23775489 DOI: 10.1007/s00429-013-0592-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 06/01/2013] [Indexed: 10/26/2022]
Abstract
LPA1 receptor is one of the six characterized G protein-coupled receptors (LPA1-6) through which lysophosphatidic acid acts as an intercellular signaling molecule. It has been proposed that this receptor has a role in controlling anxiety-like behaviors and in the detrimental consequences of stress. Here, we sought to establish the involvement of the LPA1 receptor in emotional regulation. To this end, we examined fear extinction in LPA1-null mice, wild-type and LPA1 antagonist-treated animals. In LPA1-null mice we also characterized the morphology and GABAergic properties of the amygdala and the medial prefrontal cortex. Furthermore, the expression of c-Fos protein in the amygdala and the medial prefrontal cortex, and the corticosterone response following acute stress were examined in both genotypes. Our data indicated that the absence of the LPA1 receptor significantly inhibited fear extinction. Treatment of wild-type mice with the LPA1 antagonist Ki16425 mimicked the behavioral phenotype of LPA1-null mice, revealing that the LPA1 receptor was involved in extinction. Immunohistochemistry studies revealed a reduction in the number of neurons, GABA+ cells, calcium-binding proteins and the volume of the amygdala in LPA1-null mice. Following acute stress, LPA1-null mice showed increased corticosterone and c-Fos expression in the amygdala. In conclusion, LPA1 receptor is involved in emotional behaviors and in the anatomical integrity of the corticolimbic circuit, the deregulation of which may be a susceptibility factor for anxiety disorders and a potential therapeutic target for the treatment of these diseases.
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Affiliation(s)
- C Pedraza
- Departamento de Psicobiología y Metodología de las CC, Universidad de Málaga and Instituto de Investigación Biomédica de Málaga (IBIMA), Málaga, 29071, Spain,
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75
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Choi SH, Lee BH, Kim HJ, Hwang SH, Lee SM, Nah SY. Activation of lysophosphatidic Acid receptor is coupled to enhancement of ca(2+)-activated potassium channel currents. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2013; 17:223-8. [PMID: 23776399 PMCID: PMC3682083 DOI: 10.4196/kjpp.2013.17.3.223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 05/07/2013] [Accepted: 05/22/2013] [Indexed: 11/15/2022]
Abstract
The calcium-activated K(+) (BKCa) channel is one of the potassium-selective ion channels that are present in the nervous and vascular systems. Ca(2+) is the main regulator of BKCa channel activation. The BKCa channel contains two high affinity Ca(2+) binding sites, namely, regulators of K(+) conductance, RCK1 and the Ca(2+) bowl. Lysophosphatidic acid (LPA, 1-radyl-2-hydroxy-sn-glycero-3-phosphate) is one of the neurolipids. LPA affects diverse cellular functions on many cell types through G protein-coupled LPA receptor subtypes. The activation of LPA receptors induces transient elevation of intracellular Ca(2+) levels through diverse G proteins such as Gαq/11, Gαi, Gα12/13, and Gαs and the related signal transduction pathway. In the present study, we examined LPA effects on BKCa channel activity expressed in Xenopus oocytes, which are known to endogenously express the LPA receptor. Treatment with LPA induced a large outward current in a reversible and concentration-dependent manner. However, repeated treatment with LPA induced a rapid desensitization, and the LPA receptor antagonist Ki16425 blocked LPA action. LPA-mediated BKCa channel activation was also attenuated by the PLC inhibitor U-73122, IP3 inhibitor 2-APB, Ca(2+) chelator BAPTA, or PKC inhibitor calphostin. In addition, mutations in RCK1 and RCK2 also attenuated LPA-mediated BKCa channel activation. The present study indicates that LPA-mediated activation of the BKCa channel is achieved through the PLC, IP3, Ca(2+), and PKC pathway and that LPA-mediated activation of the BKCa channel could be one of the biological effects of LPA in the nervous and vascular systems.
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Affiliation(s)
- Sun-Hye Choi
- Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Korea
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Mehedint MG, Zeisel SH. Choline's role in maintaining liver function: new evidence for epigenetic mechanisms. Curr Opin Clin Nutr Metab Care 2013; 16:339-45. [PMID: 23493015 PMCID: PMC3729018 DOI: 10.1097/mco.0b013e3283600d46] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PURPOSE OF REVIEW Humans eating diets low in choline develop fatty liver and liver damage. Rodents fed choline-methionine-deficient diets not only develop fatty liver, but also progress to develop fibrosis and hepatocarcinoma. This review focuses on the role of choline in liver function, with special emphasis on the epigenetic mechanisms of action. RECENT FINDINGS Dietary intake of methyl donors like choline influences the methylation of DNA and histones, thereby altering the epigenetic regulation of gene expression. The liver is the major organ within which methylation reactions occur, and many of the hepatic genes involved in pathways for the development of fatty liver, hepatic fibrosis, and hepatocarcinomas are epigenetically regulated. SUMMARY Dietary intake of choline varies over a three-fold range and many humans have genetic polymorphisms that increase their demand for choline. Choline is an important methyl donor needed for the generation of S-adenosylmethionine. Dietary choline intake is an important modifier of epigenetic marks on DNA and histones, and thereby modulates the gene expression in many of the pathways involved in liver function and dysfunction.
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Affiliation(s)
- Mihai G Mehedint
- Nutrition Research Institute at Kannapolis, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Nam YS, Suh JS, Song HJ, Sohn UD. Signaling pathway of lysophosphatidic Acid-induced contraction in feline esophageal smooth muscle cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2013; 17:139-47. [PMID: 23626476 PMCID: PMC3634091 DOI: 10.4196/kjpp.2013.17.2.139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 02/24/2013] [Accepted: 03/06/2013] [Indexed: 12/16/2022]
Abstract
Lysolipids such as LPA, S1P and SPC have diverse biological activities including cell proliferation, differentiation, and migration. We investigated signaling pathways of LPA-induced contraction in feline esophageal smooth muscle cells. We used freshly isolated smooth muscle cells and permeabilized cells from cat esophagus to measure the length of cells. Maximal contraction occurred at 10-6 M and the response peaked at 30s. To identify LPA receptor subtypes in cells, western blot analysis was performed with antibodies to LPA receptor subtypes. LPA1 and LPA3 receptor were detected at 50 kDa and 44 kDa. LPA-induced contraction was almost completely blocked by LPA receptor (1/3) antagonist KI16425. Pertussis toxin (PTX) inhibited the contraction induced by LPA, suggesting that the contraction is mediated by a PTX-sensitive G protein. Phospholipase C (PLC) inhibitors U73122 and neomycin, and protein kinase C (PKC) inhibitor GF109203X also reduced the contraction. The PKC-mediated contraction may be isozyme-specific since only PKCε antibody inhibited the contraction. MEK inhibitor PD98059 and JNK inhibitor SP600125 blocked the contraction. However, there is no synergistic effect of PKC and MAPK on the LPA-induced contraction. In addition, RhoA inhibitor C3 exoenzyme and ROCK inhibitor Y27632 significantly, but not completely, reduced the contraction. The present study demonstrated that LPA-induced contraction seems to be mediated by LPA receptors (1/3), coupled to PTX-sensitive G protein, resulting in activation of PLC, PKC-ε pathway, which subsequently mediates activation of ERK and JNK. The data also suggest that RhoA/ROCK are involved in the LPA-induced contraction.
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Affiliation(s)
- Yun Sung Nam
- Department of Pharmacology, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
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78
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Lancaster S, Mansell JP. The role of lysophosphatidic acid on human osteoblast formation, maturation and the implications for bone health and disease. ACTA ACUST UNITED AC 2013. [DOI: 10.2217/clp.12.86] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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79
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Kim EK, Yun SJ, Ha JM, Kim YW, Jin IH, Woo DH, Lee HS, Ha HK, Bae SS. Synergistic induction of cancer cell migration regulated by Gβγ and phosphatidylinositol 3-kinase. Exp Mol Med 2013; 44:483-91. [PMID: 22627809 PMCID: PMC3429812 DOI: 10.3858/emm.2012.44.8.055] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Phosphatidylinositol 3-kinase (PI3K) is essential for both G protein-coupled receptor (GPCR)- and receptor tyrosine kinase (RTK)-mediated cancer cell migration. Here, we have shown that maximum migration is achieved by full activation of phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) in the presence of Gβγ and PI3K signaling pathways. Lysophosphatidic acid (LPA)- induced migration was higher than that of epidermal growth factor (EGF)-induced migration; however, LPA-induced activation of Akt was lower than that stimulated by EGF. LPA-induced migration was partially blocked by either Gβγ or RTK inhibitor and completely blocked by both inhibitors. LPA-induced migration was synergistically increased in the presence of EGF and vice versa. In correlation with these results, sphingosine-1-phosphate (S1P)-induced migration was also synergistically induced in the presence of insulin-like growth factor-1 (IGF-1). Finally, silencing of P-Rex1 abolished the synergism in migration as well as in Rac activation. Moreover, synergistic activation of MMP-2 and cancer cell invasion was attenuated by silencing of P-Rex1. Given these results, we suggest that P-Rex1 requires both Gβγ and PI3K signaling pathways for synergistic activation of Rac, thereby inducing maximum cancer cell migration and invasion.
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Affiliation(s)
- Eun Kyoung Kim
- MRC for Ischemic Tissue Regeneration, Medical Research Institute, Department of Pharmacology, Pusan National University, Yangsan 626-870, Korea
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80
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Yang D, Yang W, Zhang Q, Hu Y, Bao L, Damirin A. Migration of gastric cancer cells in response to lysophosphatidic acid is mediated by LPA receptor 2. Oncol Lett 2013; 5:1048-1052. [PMID: 23426604 PMCID: PMC3576385 DOI: 10.3892/ol.2013.1107] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 12/31/2012] [Indexed: 12/12/2022] Open
Abstract
Lysophosphatidic acid (LPA), a natural phospholipid, is able to modulate diverse cellular responses through LPA receptors (LPARs). Several studies have reported that LPAR2 gene expression is increased in a variety of cancer cells, suggesting that LPAR2 is involved in gastric cancer. The present study investigated the expression profiles of the LPAR and involvement of the receptor subtypes in the LPA-induced migration of gastric cancer cells using cell migration assays, RNA interference, quantitative real-time PCR and western blotting. LPAR2 was observed to be highly expressed in SGC-7901 cells, a human gastric cancer cell line, while LPAR1 and LPAR3 were not. Transient transfection with LPAR2 siRNA was observed to reduce LPAR2 mRNA in SGC-7901 cells and eliminate the LPA-induced cell migration. It was also observed that LPA-induced SGC-7901 cell migration was inhibited by the inhibitor for Gq/11 protein and p38. The results suggest that the LPAR2/Gq/11/p38 pathway regulates LPA-induced SGC-7901 cell migration. The present findings suggest that LPAR2 may be a potential target for the clinical treatment of gastric cancer.
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Affiliation(s)
- Dezhi Yang
- College of Life Sciences, Inner Mongolia University, Huhhot, Inner Mongolia 010021, P.R. China
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81
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Mansell JP, Blackburn J. Lysophosphatidic acid, human osteoblast formation, maturation and the role of 1α,25-Dihydroxyvitamin D3 (calcitriol). Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:105-8. [DOI: 10.1016/j.bbalip.2012.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 04/16/2012] [Accepted: 04/17/2012] [Indexed: 11/30/2022]
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82
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Lysoglycerophospholipids in chronic inflammatory disorders: The PLA2/LPC and ATX/LPA axes. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:42-60. [DOI: 10.1016/j.bbalip.2012.07.019] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 07/20/2012] [Accepted: 07/24/2012] [Indexed: 02/08/2023]
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83
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Participation of analogues of lysophosphatidic acid (LPA): oleoyl-sn-glycero-3-phosphate (L-α-LPA) and 1-oleoyl-2-O-methyl-rac-glycerophosphothionate (OMPT) in uterine smooth muscle contractility of the pregnant pigs. Pol J Vet Sci 2012; 15:635-43. [DOI: 10.2478/v10181-012-0100-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract
Recent studies show that a representative of phospholipids, namely lysophosphatidic acid (LPA) and its receptors (LPA1-3) play a significant role in the reproductive processes, i. a, in the modulation of the uterine contractility. The participation of LPA3 in the reproductive processes has been revealed in mice and has not been studied in gilts. Therefore, in the present study we investigated the role/action of LPA and its receptors LPA1, LPA2 and LPA3 on the contraction activity in the porcine uterus. The study was conducted on an experimental model in which the pig uterus consisted of the one whole uterine horn and a part of the second horn, both connected with the uterine corpus. Uterine strips consisting of the endometrium with the myometrium (ENDO/MYO) and myometrium (MYO) alone were collected on days 12-14 of the estrous cycle (control group; n = 5) or pregnancy (experimental group; n = 5). Two analogues of LPA at increasing doses were used: oleoyl-sn-glycero- 3-phosphate (L-α-LPA, a selective agonist of LPA1 and LPA2 receptors; 10-7 M; 10-6 M and 10-5 M) and 1-oleoyl-2-O-methyl-rac-glycerophosphothionate (OMPT, a selective agonist of LPA3 receptor; 68 nM; 136 nM and 680 nM). L-α-LPA caused an increase in the contraction tension, amplitude and frequency of ENDO/MYO from the uterine horn with the developing embryos. This effect was not observed in MYO in both groups examined. In the ENDO/MYO strips of the uterine horn with developing embryos, OMPT significantly increased the contraction tension at the highest dose (680 nM) and amplitude at all doses examined, while frequency of contractions was decreased at doses of 136 nM and 680 nM. In the MYO strips of the uterine horn with embryos a significant increase in the contraction tension and amplitude after the highest dose of OMPT was observed. The results obtained imply the important role of receptors LPA1 , LPA2 and LPA3 in the contraction activity of the porcine uterus during early pregnancy.
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84
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Tanabe E, Kitayoshi M, Yoshikawa K, Shibata A, Honoki K, Fukushima N, Tsujiuchi T. Loss of lysophosphatidic acid receptor-3 suppresses cell migration activity of human sarcoma cells. J Recept Signal Transduct Res 2012; 32:328-34. [DOI: 10.3109/10799893.2012.738689] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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85
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Varsano T, Taupin V, Guo L, Baterina OY, Farquhar MG. The PDZ protein GIPC regulates trafficking of the LPA1 receptor from APPL signaling endosomes and attenuates the cell's response to LPA. PLoS One 2012; 7:e49227. [PMID: 23145131 PMCID: PMC3493537 DOI: 10.1371/journal.pone.0049227] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 10/07/2012] [Indexed: 12/21/2022] Open
Abstract
Lysophosphatidic acid (LPA) mediates diverse cellular responses through the activation of at least six LPA receptors – LPA1–6, but the interacting proteins and signaling pathways that mediate the specificity of these receptors are largely unknown. We noticed that LPA1 contains a PDZ binding motif (SVV) identical to that present in two other proteins that interact with the PDZ protein GIPC. GIPC is involved in endocytic trafficking of several receptors including TrkA, VEGFR2, lutropin and dopamine D2 receptors. Here we show that GIPC binds directly to the PDZ binding motif of LPA1 but not that of other LPA receptors. LPA1 colocalizes and coimmunoprecipitates with GIPC and its binding partner APPL, an activator of Akt signaling found on APPL signaling endosomes. GIPC depletion by siRNA disturbed trafficking of LPA1 to EEA1 early endosomes and promoted LPA1 mediated Akt signaling, cell proliferation, and cell motility. We propose that GIPC binds LPA1 and promotes its trafficking from APPL-containing signaling endosomes to EEA1 early endosomes and thus attenuates LPA-mediated Akt signaling from APPL endosomes.
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Affiliation(s)
- Tal Varsano
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Vanessa Taupin
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Lixia Guo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Oscar Y. Baterina
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Marilyn G. Farquhar
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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86
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Tanabe E, Shibata A, Inoue S, Kitayoshi M, Fukushima N, Tsujiuchi T. Regulation of cell motile activity through the different induction of LPA receptors by estrogens in liver epithelial WB-F344 cells. Biochem Biophys Res Commun 2012; 428:105-9. [PMID: 23058922 DOI: 10.1016/j.bbrc.2012.10.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 10/02/2012] [Indexed: 01/15/2023]
Abstract
Lysophosphatidic acid (LPA) interacts with G protein-coupled transmembrane LPA receptors (LPA receptors; LPA(1)-LPA(6)). Recently, we demonstrated that each LPA receptor acts as a positive or negative regulator of cell migration ability. It is known that estrogens indicate a variety of biological functions, including cell motility. In the present study, to assess whether LPA signaling is involved in cell motile activity stimulated by estrogens, we measured cell motile activity and LPA receptor expressions of rat liver epithelial WB-F344 cells treated with 17β-estradiol (E(2)), ethinyl estradiol (EE) and diethylstilbestrol (DES) at concentrations of 0.1 and 1.0 μM for 48 h. The cell motility of E(2) and EE treated cells was significantly higher than that of untreated cells. By contrast, DES markedly inhibited cell motile activity. Using quantitative real time RT-PCR analysis, Lpar1 and Lpar3 expressions in E(2) treated cells were significantly higher than those in untreated cells. In EE treated cells, Lpar3 expression was markedly elevated, whereas Lpar1 expression was decreased. On the other hand, Lpar1 expression was significantly increased in DES treated cells. Interestingly, the effects of E(2), EE and DES on cell motility were suppressed by Lpar1 or Lpar3 knockdown. These results suggest that the different induction of LPA receptors by estrogens may regulate cell motile activity of WB-F344 cells.
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Affiliation(s)
- Eriko Tanabe
- Division of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502, Japan
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87
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Yoshikawa K, Tanabe E, Shibata A, Inoue S, Kitayoshi M, Okimoto S, Fukushima N, Tsujiuchi T. Involvement of oncogenic K-ras on cell migration stimulated by lysophosphatidic acid receptor-2 in pancreatic cancer cells. Exp Cell Res 2012; 319:105-12. [PMID: 23041208 DOI: 10.1016/j.yexcr.2012.09.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/25/2012] [Accepted: 09/27/2012] [Indexed: 12/30/2022]
Abstract
Lysophosphatidic acid (LPA) mediates a variety of cellular responses with atleast six G protein-coupled transmembrane receptors (LPA receptor-1 (LPA(1)-LPA(6))). The interaction between LPA receptors and other cellular molecules on the biological function is not fully understood. Recently, we have reported that LPA(1) suppressed and LPA(3) stimulated cell migration of pancreatic cancer cells. In the present study, to evaluate the function of LPA(2) on motile and invasive activities of pancreatic cancer cells, we generated Lpar2 knockdown (HPD-sh2) cells from hamster pancreatic cancer cells and measured their cell migration ability. In cell motility and invasive assays with an uncoated Cell Culture Insert, HPD-sh2 cells showed significantly lower intrinsic activity than control (HPD-GFP) cells. Since K-ras mutations were frequently detected in pancreatic cancer, we next investigated whether oncogenic K-ras is involved in cell migration induced by LPA(2) using K-ras knockdown (HPD-K2) cells. The cell motile ability of HPD-K2 cells was significantly lower than that of control cells. To confirm LPA(2) increases cell migration activity, cells were pretreated with dioctylglycerol pyrophosphate (DGPP) which is the antagonist of LPA(1)/LPA(3). The cell motile and invasive abilities of DGPP -treated HPD-GFP cells were markedly higher than those of untreated cells, but DGPP did not stimulate cell migration of HPD-K2 cells. These results suggest that cell migration activity of pancreatic cancer cells stimulated by LPA(2) may be enhanced by oncogenic K-ras.
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Affiliation(s)
- Kyohei Yoshikawa
- Division of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, Higashiosaka, Osaka, Japan
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88
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Fukui R, Kato K, Okabe K, Kitayoshi M, Tanabe E, Fukushima N, Tsujiuchi T. Enhancement of Drug Resistance by Lysophosphatidic Acid Receptor-3 in Mouse Mammary Tumor FM3A Cells. J Toxicol Pathol 2012; 25:225-8. [PMID: 22988342 PMCID: PMC3434339 DOI: 10.1293/tox.25.225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/01/2012] [Indexed: 11/19/2022] Open
Abstract
Lysophosphatidic acid (LPA) acts as a simple phospholipid that interacts with G protein-coupled transmembrane LPA receptors. Recently, it has been reported that each LPA receptor plays different biological roles in acquisition of the malignant property of tumor cells. In this study, to assess the involvement of LPA receptor-3 (LPA(3)) in cell survival after treatment with anticancer drugs, we generated Lpar3-expressing FM3A-a3A9 cells from mouse mammary tumor FM3A cells and examined the cell survival rate after treatment with anticancer drugs compared with Lpar3-unexpressing cells. Cells were treated with 0.005 to 10 μM of cisplatin (CDDP) or doxorubicin (DOX) for 3 days. For the CDDP and DOX treatments, the cell survival rate of FM3A-a3A9 cells was significantly higher than that of Lpar3-unexpressing cells. The expression level of the Mdr1a gene in FM3A-a3A9 cells was higher than that of Lpar3-unexpressing cells, whereas no significant difference in multidrug resistance 1b (Mdr1b) and glutathione S-transferase mu1 (Gstm1) expressions was found. These results suggest that LPA(3) may enhance the cell survival rate after treatment with anticancer drugs in mouse mammary tumor cells, correlating with increased expression of the Mdr1 gene.
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Affiliation(s)
- Rie Fukui
- Division of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502, Japan
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89
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Marshall JCA, Collins JW, Nakayama J, Horak CE, Liewehr DJ, Steinberg SM, Albaugh M, Vidal-Vanaclocha F, Palmieri D, Barbier M, Murone M, Steeg PS. Effect of inhibition of the lysophosphatidic acid receptor 1 on metastasis and metastatic dormancy in breast cancer. J Natl Cancer Inst 2012; 104:1306-19. [PMID: 22911670 DOI: 10.1093/jnci/djs319] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Previous studies identified the human nonmetastatic gene 23 (NME1, hereafter Nm23-H1) as the first metastasis suppressor gene. An inverse relationship between Nm23-H1 and expression of lysophosphatidic acid receptor 1 gene (LPAR1, also known as EDG2 or hereafter LPA1) has also been reported. However, the effects of LPA1 inhibition on primary tumor size, metastasis, and metastatic dormancy have not been investigated. METHODS The LPA1 inhibitor Debio-0719 or LPA1 short hairpinned RNA (shRNA) was used. Primary tumor size and metastasis were investigated using the 4T1 spontaneous metastasis mouse model and the MDA-MB-231T experimental metastasis mouse model (n = 13 mice per group). Proliferation and p38 intracellular signaling in tumors and cell lines were determined by immunohistochemistry and western blot to investigate the effects of LPA1 inhibition on metastatic dormancy. An analysis of variance-based two-tailed t test was used to determine a statistically significant difference between treatment groups. RESULTS In the 4T1 spontaneous metastasis mouse model, Debio-0719 inhibited the metastasis of 4T1 cells to the liver (mean = 25.2 liver metastases per histologic section for vehicle-treated mice vs 6.8 for Debio-0719-treated mice, 73.0% reduction, P < .001) and lungs (mean = 6.37 lesions per histologic section for vehicle-treated mice vs 0.73 for Debio-0719-treated mice, 88.5% reduction, P < .001), with no effect on primary tumor size. Similar results were observed using the MDA-MB-231T experimental pulmonary metastasis mouse model. LPA1 shRNA also inhibited metastasis but did not affect primary tumor size. In 4T1 metastases, but not primary tumors, expression of the proliferative markers Ki67 and pErk was reduced by Debio-0719, and phosphorylation of the p38 stress kinase was increased, indicative of metastatic dormancy. CONCLUSION The data identify Debio-0719 as a drug candidate with metastasis suppressor activity, inducing dormancy at secondary tumor sites.
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Affiliation(s)
- Jean-Claude A Marshall
- The Women's Cancers Section, Laboratory of Molecular Pharmacology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892, USA
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90
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Lee JH, Kim DG, Bae TJ, Rho K, Kim JT, Lee JJ, Jang Y, Kim BC, Park KM, Kim S. CDA: combinatorial drug discovery using transcriptional response modules. PLoS One 2012; 7:e42573. [PMID: 22905152 PMCID: PMC3414439 DOI: 10.1371/journal.pone.0042573] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 07/09/2012] [Indexed: 11/18/2022] Open
Abstract
Background Anticancer therapies that target single signal transduction pathways often fail to prevent proliferation of cancer cells because of overlapping functions and cross-talk between different signaling pathways. Recent research has identified that balanced multi-component therapies might be more efficacious than highly specific single component therapies in certain cases. Ideally, synergistic combinations can provide 1) increased efficacy of the therapeutic effect 2) reduced toxicity as a result of decreased dosage providing equivalent or increased efficacy 3) the avoidance or delayed onset of drug resistance. Therefore, the interest in combinatorial drug discovery based on systems-oriented approaches has been increasing steadily in recent years. Methodology Here we describe the development of Combinatorial Drug Assembler (CDA), a genomics and bioinformatics system, whereby using gene expression profiling, multiple signaling pathways are targeted for combinatorial drug discovery. CDA performs expression pattern matching of signaling pathway components to compare genes expressed in an input cell line (or patient sample data), with expression patterns in cell lines treated with different small molecules. Then it detects best pattern matching combinatorial drug pairs across the input gene set-related signaling pathways to detect where gene expression patterns overlap and those predicted drug pairs could likely be applied as combination therapy. We carried out in vitro validations on non-small cell lung cancer cells and triple-negative breast cancer (TNBC) cells. We found two combinatorial drug pairs that showed synergistic effect on lung cancer cells. Furthermore, we also observed that halofantrine and vinblastine were synergistic on TNBC cells. Conclusions CDA provides a new way for rational drug combination. Together with phExplorer, CDA also provides functional insights into combinatorial drugs. CDA is freely available at http://cda.i-pharm.org.
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Affiliation(s)
- Ji-Hyun Lee
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
- Information Center for Bio-pharmacological Network, Seoul National University, Suwon, South Korea
| | - Dae Gyu Kim
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
| | - Tae Jeong Bae
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
- Information Center for Bio-pharmacological Network, Seoul National University, Suwon, South Korea
| | - Kyoohyoung Rho
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
- Information Center for Bio-pharmacological Network, Seoul National University, Suwon, South Korea
| | - Ji-Tae Kim
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
- Information Center for Bio-pharmacological Network, Seoul National University, Suwon, South Korea
| | - Jong-Jun Lee
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
| | - Yeongjun Jang
- Korean BioInformation Center (KOBIC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Deajeon, South Korea
| | - Byung Cheol Kim
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
| | - Kyoung Mii Park
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
- Information Center for Bio-pharmacological Network, Seoul National University, Suwon, South Korea
| | - Sunghoon Kim
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, South Korea
- WCU Department of Molecular Medicine and Biopharmaceutical Sciences, Seoul National University, Seoul, South Korea
- * E-mail:
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91
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Choi JW, Chun J. Lysophospholipids and their receptors in the central nervous system. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:20-32. [PMID: 22884303 DOI: 10.1016/j.bbalip.2012.07.015] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 07/17/2012] [Accepted: 07/18/2012] [Indexed: 02/05/2023]
Abstract
Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), two of the best-studied lysophospholipids, are known to influence diverse biological events, including organismal development as well as function and pathogenesis within multiple organ systems. These functional roles are due to a family of at least 11 G protein-coupled receptors (GPCRs), named LPA(1-6) and S1P(1-5), which are widely distributed throughout the body and that activate multiple effector pathways initiated by a range of heterotrimeric G proteins including G(i/o), G(12/13), G(q) and G(s), with actual activation dependent on receptor subtypes. In the central nervous system (CNS), a major locus for these signaling pathways, LPA and S1P have been shown to influence myriad responses in neurons and glial cell types through their cognate receptors. These receptor-mediated activities can contribute to disease pathogenesis and have therapeutic relevance to human CNS disorders as demonstrated for multiple sclerosis (MS) and possibly others that include congenital hydrocephalus, ischemic stroke, neurotrauma, neuropsychiatric disorders, developmental disorders, seizures, hearing loss, and Sandhoff disease, based upon the experimental literature. In particular, FTY720 (fingolimod, Gilenya, Novartis Pharma, AG) that becomes an analog of S1P upon phosphorylation, was approved by the FDA in 2010 as a first oral treatment for MS, validating this class of receptors as medicinal targets. This review will provide an overview and update on the biological functions of LPA and S1P signaling in the CNS, with a focus on results from studies using genetic null mutants for LPA and S1P receptors. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.
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Affiliation(s)
- Ji Woong Choi
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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92
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Zhao Y, Natarajan V. Lysophosphatidic acid (LPA) and its receptors: role in airway inflammation and remodeling. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:86-92. [PMID: 22809994 DOI: 10.1016/j.bbalip.2012.06.014] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 06/27/2012] [Accepted: 06/29/2012] [Indexed: 12/14/2022]
Abstract
Lysophosphatidic acid (LPA), a simple bioactive phospholipid, is present in biological fluids such as plasma and bronchoalveolar lavage (BAL). It appears to have both pro- and anti-inflammatory roles in inflammatory lung diseases. Exogenous LPA promotes inflammatory responses by regulating the expression of chemokines, cytokines, and cytokine receptors in lung epithelial cells. In addition to the modulation of inflammatory responses, LPA regulates cytoskeleton rearrangement and confers protection against lung injury by enhancing lung epithelial cell barrier integrity and remodeling. The biological effects of LPA are mediated through its cell surface G-protein coupled LPA(1-7) receptors. The roles of LPA receptors in lung fibrosis, asthma, and acute lung injury have been investigated using genetically engineered LPA receptor deficient mice and there appears to be a definitive role for endogenous LPA and its receptors in the pathogenesis of pulmonary inflammatory diseases. This review summarizes recent reports on the role of LPA and its receptors in the regulation of lung epithelial inflammatory responses and remodeling. This article is part of a Special Issue entitled: Advances in Lysophospholipid Research.
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Affiliation(s)
- Yutong Zhao
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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93
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Fukui R, Tanabe E, Kitayoshi M, Yoshikawa K, Fukushima N, Tsujiuchi T. Negative regulation of cell motile and invasive activities by lysophosphatidic acid receptor-3 in colon cancer HCT116 cells. Tumour Biol 2012; 33:1899-905. [DOI: 10.1007/s13277-012-0450-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 06/22/2012] [Indexed: 01/11/2023] Open
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94
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Kitayoshi M, Fukui R, Tanabe E, Kato K, Yoshikawa K, Fukushima N, Tsujiuchi T. Different effects on cell proliferation and migration abilities of endothelial cells by LPA1and LPA3in mammary tumor FM3A cells. J Recept Signal Transduct Res 2012; 32:209-13. [DOI: 10.3109/10799893.2012.692121] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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95
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Opposite roles of LPA1 and LPA3 on cell motile and invasive activities of pancreatic cancer cells. Tumour Biol 2012; 33:1739-44. [DOI: 10.1007/s13277-012-0433-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 05/28/2012] [Indexed: 12/30/2022] Open
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96
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Kitayoshi M, Kato K, Tanabe E, Yoshikawa K, Fukui R, Fukushima N, Tsujiuchi T. Enhancement of endothelial cell migration by constitutively active LPA1-expressing tumor cells. Biochem Biophys Res Commun 2012; 422:339-43. [DOI: 10.1016/j.bbrc.2012.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 05/02/2012] [Indexed: 12/27/2022]
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97
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Sato T, Sugimoto K, Inoue A, Okudaira S, Aoki J, Tokuyama H. Synthesis and biological evaluation of optically active Ki16425. Bioorg Med Chem Lett 2012; 22:4323-6. [PMID: 22658556 DOI: 10.1016/j.bmcl.2012.05.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 05/02/2012] [Accepted: 05/04/2012] [Indexed: 11/30/2022]
Abstract
An enantionselective synthesis of both enantiomers of Ki16425, which possesses selective LPA antagonistic activity, was achieved. The isoxazole core was constructed by a 1,3-dipolar cycloaddition of nitrile oxide with alkyne and condensation with the optically active α-phenethyl alcohol segment, which was prepared by an enantioselective reduction of arylmethylketone. Biological evaluation of both enantiomers of Ki16425 revealed that the (R)-isomer showed much higher antagonistic activity for LPA(1) and LPA(3) receptors.
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Affiliation(s)
- Takanao Sato
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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98
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Choi HJ, Han JS. Overexpression of phospholipase D enhances Bcl-2 expression by activating STAT3 through independent activation of ERK and p38MAPK in HeLa cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1082-91. [PMID: 22504301 DOI: 10.1016/j.bbamcr.2012.03.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 03/06/2012] [Accepted: 03/26/2012] [Indexed: 11/17/2022]
Abstract
The purpose of this study was to identify the role of phospholipase D (PLD) isozymes in Bcl-2 expression. Overexpression of PLD1 or PLD2 increased Bcl-2 expression and phosphatidic acid (PA), the product of PLDs, also upregulated Bcl-2 expression. Treatment with PA activated the phospholipase A(2) (PLA(2))/G(i)/ERK1/2, RhoA/Rho-associated kinase (ROCK)/p38 MAPK, and Rac1/p38 MAPK pathways. PA-induced phosphorylation of ERK1/2 was attenuated by a PLA(2) inhibitor (mepacrine) and, a G(i) protein inhibitor (pertussis toxin, PTX). On the other hand, p38 MAPK phosphorylation was attenuated by a dominant negative Rac1 and a specific Rho-kinase inhibitor (Y-27632). These results suggest that PLA(2)/G(i) acts at the upstream of ERK1/2, while Rac1 and RhoA/ROCK act upstream of p38 MAPK. We next, tried to determine which transcription factor is involved in PLD-related Bcl-2 expression. When signal transducer and activator of transcription 3 (STAT3) activity was blocked by a STAT3 specific siRNA, PA-induced Bcl-2 expression was remarkably decreased, suggesting that STAT3 is an essential transcription factor linking PLD to Bcl-2 upregulation. Taken together, these findings indicate that PLD acts as an important regulator in Bcl-2 expression by activating STAT3 involving the phosphorylation of Ser727 through the PLA(2)/G(i)/ERK1/2, RhoA/ROCK/p38 MAPK, and Rac1/p38 MAPK pathways.
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Affiliation(s)
- Hye-Jin Choi
- Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, Seoul, Republic of Korea
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99
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Furuta D, Yamane M, Tsujiuchi T, Moriyama R, Fukushima N. Lysophosphatidic acid induces neurite branch formation through LPA3. Mol Cell Neurosci 2012; 50:21-34. [PMID: 22465231 DOI: 10.1016/j.mcn.2012.03.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 02/03/2012] [Accepted: 03/14/2012] [Indexed: 01/13/2023] Open
Abstract
Although neurite branching is crucial for neuronal network formation after birth, its underlying mechanisms remain unclear. Here, we demonstrate that lysophosphatidic acid (LPA) stimulates neurite branching through a novel signaling pathway. Treatment of neuronal cell lines with LPA resulted in neurite branch formation when LPA(3) receptor was introduced. The effects of LPA were blocked by inhibition of G(q) signaling. Furthermore, expression of inhibitory mutants of the small GTPase Rnd2/Rho7 or an Rnd2 effector rapostlin abolished LPA(3)-mediated neurite branching. The LPA(3) agonist 2(S)-OMPT or LPA also induced axonal branch formation in hippocampal neurons, which was blocked by G(q) and Rnd2 pathway inhibition or LPA(3) knockdown. These findings suggest that the novel signaling pathway involving LPA(3), G(q), and Rnd2 may play an important role in neuronal network formation.
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Affiliation(s)
- Daisuke Furuta
- Division of Molecular Neurobiology, Department of Life Science, Kinki University, Higashiosaka, Japan
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100
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Singla A, Kumar A, Priyamvada S, Tahniyath M, Saksena S, Gill RK, Alrefai WA, Dudeja PK. LPA stimulates intestinal DRA gene transcription via LPA2 receptor, PI3K/AKT, and c-Fos-dependent pathway. Am J Physiol Gastrointest Liver Physiol 2012; 302:G618-27. [PMID: 22159277 PMCID: PMC3311307 DOI: 10.1152/ajpgi.00172.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
DRA (downregulated in adenoma) or SLC26A3 is the major apical anion exchanger mediating Cl(-) absorption in intestinal epithelial cells. Disturbances in DRA function and expression have been implicated in diarrheal conditions such as congenital chloride diarrhea and inflammatory bowel diseases. Previous studies have shown that DRA is subject to regulation by short-term and transcriptional mechanisms. In this regard, we have recently shown that short-term treatment by lysophosphatidic acid (LPA), an important bioactive phospholipid, stimulates Cl(-)/HCO(3)(-)(OH(-)) exchange activity via an increase in DRA surface levels in human intestinal epithelial cells. However, the long-term effects of LPA on DRA at the level of gene transcription have not been examined. The present studies were aimed at investigating the effects of LPA on DRA function and expression as well as elucidating the mechanisms underlying its transcriptional regulation. Long-term LPA treatment increased the Cl(-)/HCO(3)(-) exchange activity in Caco-2 cells. LPA treatment (50-100 μM) of Caco-2 cells significantly stimulated DRA mRNA levels and DRA promoter activity (-1183/+114). This increase in DRA promoter activity involved the LPA2 receptor and phosphatidylinositol 3-kinase (PI3K)/AKT pathways. Progressive deletions from -1183/+114 to -790/+114 abrogated the stimulatory effects of LPA, indicating that the -1183/-790 promoter region harbors LPA response elements. Utilizing EMSA and mutational studies, our results showed that LPA induced the DRA promoter activity in a c-Fos-dependent manner. LPA also increased the protein expression of c-Fos and c-Jun in Caco-2 cells. Furthermore, overexpression of c-Fos but not c-Jun enhanced the DRA promoter activity. This increase in DRA transcription in response to LPA indicates that LPA may act as an antidiarrheal agent and could be exploited for the treatment of diarrhea associated with inflammatory or infectious diseases of the gut.
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Affiliation(s)
- Amika Singla
- 1Section of Digestive Diseases and Nutrition, Dept. of Medicine and ,2Department of Physiology and Biophysics, University of Illinois at Chicago and
| | - Anoop Kumar
- 1Section of Digestive Diseases and Nutrition, Dept. of Medicine and
| | | | - Maliha Tahniyath
- 1Section of Digestive Diseases and Nutrition, Dept. of Medicine and
| | - Seema Saksena
- 1Section of Digestive Diseases and Nutrition, Dept. of Medicine and
| | - Ravinder K. Gill
- 1Section of Digestive Diseases and Nutrition, Dept. of Medicine and
| | - Waddah A. Alrefai
- 1Section of Digestive Diseases and Nutrition, Dept. of Medicine and ,3Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Pradeep K. Dudeja
- 1Section of Digestive Diseases and Nutrition, Dept. of Medicine and ,3Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
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