1
|
Fujita H, Adachi C, Inoue T. Cholesterol-load evokes robust calcium response in macrophages: An early event toward cholesterol-induced macrophage death. Cell Calcium 2023; 113:102754. [PMID: 37196488 DOI: 10.1016/j.ceca.2023.102754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/27/2023] [Accepted: 05/09/2023] [Indexed: 05/19/2023]
Abstract
Macrophages in atherosclerotic lesions accumulate large amounts of unesterified cholesterol. Excess cholesterol load leads to cell death of macrophages, which is associated with the progression of atherosclerotic lesions. Calcium depletion in the endoplasmic reticulum (ER) and subsequent pro-apoptotic aberrant calcium signaling are key events in cholesterol-induced macrophage death. Although these concepts imply cytoplasmic calcium events in cholesterol-loaded macrophages, the mechanisms linking cholesterol accumulation to cytoplasmic calcium response have been poorly investigated. Based on our previous finding that extracellularly applied cholesterol evoked robust calcium oscillations in astrocytes, a type of glial cells in the brain, we hypothesized that cholesterol accumulation in macrophages triggers cytoplasmic calcium elevation. Here, we showed that cholesterol application induces calcium transients in THP-1-derived and peritoneal macrophages. Inhibition of inositol 1,4,5-trisphosphate receptors (IP3Rs) and l-type calcium channels (LTCCs) prevented cholesterol-induced calcium transients and ameliorated cholesterol-induced macrophage death. These results suggest that cholesterol-induced calcium transients through IP3Rs and LTCCs are crucial mechanisms underlying cholesterol-induced cell death of macrophages.
Collapse
Affiliation(s)
- Hirotaka Fujita
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo, 162-8480, Japan
| | - Chihiro Adachi
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo, 162-8480, Japan
| | - Takafumi Inoue
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo, 162-8480, Japan.
| |
Collapse
|
2
|
Katunin P, Zhou J, Shehata OM, Peden AA, Cadby A, Nikolaev A. An Open-Source Framework for Automated High-Throughput Cell Biology Experiments. Front Cell Dev Biol 2021; 9:697584. [PMID: 34631697 PMCID: PMC8498207 DOI: 10.3389/fcell.2021.697584] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022] Open
Abstract
Modern data analysis methods, such as optimization algorithms or deep learning have been successfully applied to a number of biotechnological and medical questions. For these methods to be efficient, a large number of high-quality and reproducible experiments needs to be conducted, requiring a high degree of automation. Here, we present an open-source hardware and low-cost framework that allows for automatic high-throughput generation of large amounts of cell biology data. Our design consists of an epifluorescent microscope with automated XY stage for moving a multiwell plate containing cells and a perfusion manifold allowing programmed application of up to eight different solutions. Our system is very flexible and can be adapted easily for individual experimental needs. To demonstrate the utility of the system, we have used it to perform high-throughput Ca2+ imaging and large-scale fluorescent labeling experiments.
Collapse
Affiliation(s)
- Pavel Katunin
- Fresco Labs, London, United Kingdom
- Information Technologies and Programming Faculty, ITMO University, St. Petersburg, Russia
| | - Jianbo Zhou
- Department of Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Ola M Shehata
- Department of Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Andrew A Peden
- Department of Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Ashley Cadby
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | - Anton Nikolaev
- Department of Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom
| |
Collapse
|
3
|
Schreuder WH, van der Wal JE, de Lange J, van den Berg H. Multiple versus solitary giant cell lesions of the jaw: Similar or distinct entities? Bone 2021; 149:115935. [PMID: 33771761 DOI: 10.1016/j.bone.2021.115935] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 02/27/2021] [Accepted: 03/17/2021] [Indexed: 02/06/2023]
Abstract
The majority of giant cell lesions of the jaw present as a solitary focus of disease in bones of the maxillofacial skeleton. Less frequently they occur as multifocal lesions. This raises the clinical dilemma if these should be considered distinct entities and therefore each need a specific therapeutic approach. Solitary giant cell lesions of the jaw present with a great diversity of symptoms. Recent molecular analysis revealed that these are associated with somatic gain-of-function mutations in KRAS, FGFR1 or TRPV4 in a large component of the mononuclear stromal cells which all act on the RAS/MAPK pathway. For multifocal lesions, a small group of neoplastic multifocal giant cell lesions of the jaw remain after ruling out hyperparathyroidism. Strikingly, most of these patients are diagnosed with jaw lesions before the age of 20 years, thus before the completion of dental and jaw development. These multifocal lesions are often accompanied by a diagnosis or strong clinical suspicion of a syndrome. Many of the frequently reported syndromes belong to the so-called RASopathies, with germline or mosaic mutations leading to downstream upregulation of the RAS/MAPK pathway. The other frequently reported syndrome is cherubism, with gain-of-function mutations in the SH3BP2 gene leading through assumed and unknown signaling to an autoinflammatory bone disorder with hyperactive osteoclasts and defective osteoblastogenesis. Based on this extensive literature review, a RAS/MAPK pathway activation is hypothesized in all giant cell lesions of the jaw. The different interaction between and contribution of deregulated signaling in individual cell lineages and crosstalk with other pathways among the different germline- and non-germline-based alterations causing giant cell lesions of the jaw can be explanatory for the characteristic clinical features. As such, this might also aid in the understanding of the age-dependent symptomatology of syndrome associated giant cell lesions of the jaw; hopefully guiding ideal timing when installing treatment strategies in the future.
Collapse
Affiliation(s)
- Willem H Schreuder
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Center for Dentistry Amsterdam, University of Amsterdam, Amsterdam, the Netherlands; Department of Head and Neck Surgery and Oncology, Antoni van Leeuwenhoek / Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Jacqueline E van der Wal
- Department of Pathology, Antoni van Leeuwenhoek / Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Jan de Lange
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Center for Dentistry Amsterdam, University of Amsterdam, Amsterdam, the Netherlands
| | - Henk van den Berg
- Department of Pediatrics / Oncology, Amsterdam UMC, University of Amsterdam, Emma Children's Hospital, Amsterdam, the Netherlands
| |
Collapse
|
4
|
Nakagawa T, Takahashi C, Matsuzaki H, Kuroda Y, Higashi H. Regulation of membrane raft recruitment of the bradykinin B2 receptor by close association with the ATP/UTP receptor P2Y 2. Biochem Biophys Res Commun 2018; 505:36-39. [PMID: 30236981 DOI: 10.1016/j.bbrc.2018.09.072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 09/12/2018] [Indexed: 10/28/2022]
Abstract
Several G protein-coupled receptors are present in lipid rafts. We have shown that most of the P2Y2 receptor (P2Y2R) protein is fractionated into lipid rafts in COS 7 cells. In the same cells, about 25-30% of the bradykinin B2 receptor (B2R) protein is also fractionated into lipid rafts. When both P2Y2R and B2R are co-expressed, the distribution of P2Y2R remained unchanged, but more B2R shifted into the raft fraction. This indicates that the interaction between both receptors recruited B2R into the lipid rafts. After 15 min of UTP stimulation, both receptors almost completely disappeared from the cell surface by endocytosis as observed with a confocal fluorescence microscope. Furthermore, with bradykinin stimulation for 15 min, portions of both receptors disappeared from the cell surface and were endocytosed. As we reported previously with both CHO-K1 cells and HEK 293 cells, continuous stimulation of COS7 cells with GT1b and CSC resulted in the disappearance of both P2Y2R and B2R from the cell membrane surface. Thus, both P2Y2R and B2R migrate into membrane rafts and are endocytosed in parallel with signal crosstalk, clearly indicating that both closely interact on membrane rafts. The P2Y2R N-glycosylation deficient mutant does not migrate to the cell surface. It remains predominantly in the endoplasmic reticulum and is fractionated into raft fractions. In the presence of this glycosylation mutant, most of B2R remains in the endoplasmic reticulum, and is fractionated into the raft fraction. These findings demonstrate that in the membrane rafts of the endoplasmic reticulum, both receptors are already closely associated, and B2R shifts into the rafts by affinity with P2Y2R.
Collapse
Affiliation(s)
- Tetsuto Nakagawa
- Division of Glyco-Signal Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, 981-8558, Japan
| | - Chihiro Takahashi
- Division of Glyco-Signal Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, 981-8558, Japan
| | - Hitomi Matsuzaki
- Division of Glyco-Signal Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, 981-8558, Japan
| | - Yoshiyuki Kuroda
- Division of Glyco-Signal Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, 981-8558, Japan
| | - Hideyoshi Higashi
- Division of Glyco-Signal Research, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, 981-8558, Japan.
| |
Collapse
|
5
|
Casas J, Ibarguren M, Álvarez R, Terés S, Lladó V, Piotto SP, Concilio S, Busquets X, López DJ, Escribá PV. G protein-membrane interactions II: Effect of G protein-linked lipids on membrane structure and G protein-membrane interactions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1526-1535. [PMID: 28411171 DOI: 10.1016/j.bbamem.2017.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/21/2017] [Accepted: 04/09/2017] [Indexed: 10/19/2022]
Abstract
G proteins often bear myristoyl, palmitoyl and isoprenyl moieties, which favor their association with the membrane and their accumulation in G Protein Coupled Receptor-rich microdomains. These lipids influence the biophysical properties of membranes and thereby modulate G protein binding to bilayers. In this context, we showed here that geranylgeraniol, but neither myristate nor palmitate, increased the inverted hexagonal (HII) phase propensity of phosphatidylethanolamine-containing membranes. While myristate and palmitate preferentially associated with phosphatidylcholine membranes, geranylgeraniol favored nonlamellar-prone membranes. In addition, Gαi1 monomers had a higher affinity for lamellar phases, while Gβγ and Gαβγ showed a marked preference for nonlamellar prone membranes. Moreover, geranylgeraniol enhanced the binding of G protein dimers and trimers to phosphatidylethanolamine-containing membranes, yet it decreased that of monomers. By contrast, both myristate and palmitate increased the Gαi1 preference for lamellar membranes. Palmitoylation reinforced the binding of the monomer to PC membranes and myristoylation decreased its binding to PE-enriched bilayer. Finally, binding of dimers and trimers to lamellar-prone membranes was decreased by palmitate and myristate, but it was increased in nonlamellar-prone bilayers. These results demonstrate that co/post-translational G protein lipid modifications regulate the membrane lipid structure and that they influence the physico-chemical properties of membranes, which in part explains why G protein subunits sort to different plasma membrane domains. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
Collapse
Affiliation(s)
- Jesús Casas
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Maitane Ibarguren
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain; Lipopharma Therapeutics, S.L., ParcBit, 07121 Palma de Mallorca, Spain
| | - Rafael Álvarez
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Silvia Terés
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain; Lipopharma Therapeutics, S.L., ParcBit, 07121 Palma de Mallorca, Spain
| | - Victoria Lladó
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - Stefano P Piotto
- Department of Pharmacy, University of Salerno, Via Ponte don Melillo, 84084 Fisciano, SA, Italy
| | - Simona Concilio
- Department of Industrial Engineering, University of Salerno, Via Ponte don Melillo, 84084 Fisciano, SA, Italy
| | - Xavier Busquets
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| | - David J López
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain; Lipopharma Therapeutics, S.L., ParcBit, 07121 Palma de Mallorca, Spain.
| | - Pablo V Escribá
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain
| |
Collapse
|
6
|
N -glycan-dependent cell-surface expression of the P2Y 2 receptor and N -glycan-independent distribution to lipid rafts. Biochem Biophys Res Commun 2017; 485:427-431. [DOI: 10.1016/j.bbrc.2017.02.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 02/10/2017] [Indexed: 01/23/2023]
|
7
|
Wolf C, Qian Y, Brooke MA, Kelsell DP, Franzke CW. ADAM17/EGFR axis promotes transglutaminase-dependent skin barrier formation through phospholipase C γ1 and protein kinase C pathways. Sci Rep 2016; 6:39780. [PMID: 28004780 PMCID: PMC5177948 DOI: 10.1038/srep39780] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 11/28/2016] [Indexed: 12/21/2022] Open
Abstract
The vitally important skin barrier is formed by extensive cross-linking activity of transglutaminases (TGs) during terminal epidermal differentiation. We have previously shown that epidermal deficiency of a disintegrin and metalloproteinase 17 (ADAM17), the principal EGFR ligand sheddase, results in postnatal skin barrier defects in mice due to impeded TG activity. However, the mechanism by which ADAM17/EGFR signalling maintains TG activity during epidermal differentiation remains elusive. Here we demonstrate that ADAM17-dependent EGFR signalling promotes TG activity in keratinocytes committed to terminal differentiation by direct induction of TG1 expression. Restored TG1 expression of EGF-stimulated differentiated Adam17-/- keratinocytes was strongly repressed by inhibitors for PLCγ1 or protein kinase C (PKC) pathways, while treatment with the PKC stimulator 12-O-tetradecanoylphorbol-13-acetate restored TG activity in the epidermis of keratinocyte-specific Adam17-/- (AD17ΔKC) mice. Further investigations emphasized the expression of PKCη, a mediator of TGM1 transcription, to be sensitive to EGFR activation. In agreement, topical skin application of cholesterol sulfate, an activator of PKCη, significantly improved TG activity in epidermis of AD17ΔKC mice. Our results suggest ADAM17/EGFR-driven PLCγ1 and PKC pathways as important promoters of TG1 expression during terminal keratinocyte differentiation. These findings may help to identify new therapeutic targets for inflammatory skin diseases related to epidermal barrier defects.
Collapse
Affiliation(s)
- Cristina Wolf
- Department of Dermatology, Medical Center - University of Freiburg, Freiburg, Germany
| | - Yawen Qian
- Department of Dermatology, Medical Center - University of Freiburg, Freiburg, Germany
| | - Matthew A. Brooke
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - David P. Kelsell
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Claus-Werner Franzke
- Department of Dermatology, Medical Center - University of Freiburg, Freiburg, Germany
| |
Collapse
|
8
|
Chun YS, Oh HG, Park MK, Cho H, Chung S. Cholesterol regulates HERG K+ channel activation by increasing phospholipase C β1 expression. Channels (Austin) 2013; 7:275-87. [PMID: 23793622 DOI: 10.4161/chan.25122] [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] [Indexed: 01/26/2023] Open
Abstract
Human ether-a-go-go-related gene (HERG) K(+) channel underlies the rapidly activating delayed rectifier K(+) conductance (IKr) during normal cardiac repolarization. Also, it may regulate excitability in many neuronal cells. Recently, we showed that enrichment of cell membrane with cholesterol inhibits HERG channels by reducing the levels of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] due to the activation of phospholipase C (PLC). In this study, we further explored the effect of cholesterol enrichment on HERG channel kinetics. When membrane cholesterol level was mildly increased in human embryonic kidney (HEK) 293 cells expressing HERG channel, the inactivation and deactivation kinetics of HERG current were not affected, but the activation rate was significantly decelerated at all voltages tested. The application of PtdIns(4,5)P2 or inhibitor for PLC prevented the effect of cholesterol enrichment, while the presence of antibody against PtdIns(4,5)P2 in pipette solution mimicked the effect of cholesterol enrichment. These results indicate that the effect of cholesterol enrichment on HERG channel is due to the depletion of PtdIns(4,5)P2. We also found that cholesterol enrichment significantly increases the expression of β1 and β3 isoforms of PLC (PLCβ1, PLCβ3) in the membrane. Since the effects of cholesterol enrichment on HERG channel were prevented by inhibiting transcription or by inhibiting PLCβ1 expression, we conclude that increased PLCβ1 expression leads to the deceleration of HERG channel activation rate via downregulation of PtdIns(4,5)P2. These results confirm a crosstalk between two plasma membrane-enriched lipids, cholesterol and PtdIns(4,5)P2, in the regulation of HERG channels.
Collapse
Affiliation(s)
- Yoon Sun Chun
- Department of Physiology; Samsung Biomedical Research Institute; Sungkyunkwan University School of Medicine; Suwon, South Korea
| | | | | | | | | |
Collapse
|
9
|
Cellular functions regulated by phosphorylation of EGFR on Tyr845. Int J Mol Sci 2013; 14:10761-90. [PMID: 23702846 PMCID: PMC3709701 DOI: 10.3390/ijms140610761] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/06/2013] [Accepted: 05/13/2013] [Indexed: 11/17/2022] Open
Abstract
The Src gene product (Src) and the epidermal growth factor receptor (EGFR) are prototypes of oncogene products and function primarily as a cytoplasmic non-receptor tyrosine kinase and a transmembrane receptor tyrosine kinase, respectively. The identification of Src and EGFR, and the subsequent extensive investigations of these proteins have long provided cutting edge research in cancer and other molecular and cellular biological studies. In 1995, we reported that the human epidermoid carcinoma cells, A431, contain a small fraction of Src and EGFR in which these two kinase were in physical association with each other, and that Src phosphorylates EGFR on tyrosine 845 (Y845) in the Src-EGFR complex. Y845 of EGFR is located in the activation segment of the kinase domain, where many protein kinases contain kinase-activating autophosphorylation sites (e.g., cAMP-dependent protein kinase, Src family kinases, transmembrane receptor type tyrosine kinases) or trans-phosphorylation sites (e.g., cyclin-dependent protein kinase, mitogen-activated protein kinase, Akt protein kinase). A number of studies have demonstrated that Y845 phosphorylation serves an important role in cancer as well as normal cells. Here we compile the experimental facts involving Src phosphorylation of EGFR on Y845, by which cell proliferation, cell cycle control, mitochondrial regulation of cell metabolism, gamete activation and other cellular functions are regulated. We also discuss the physiological relevance, as well as structural insights of the Y845 phosphorylation.
Collapse
|
10
|
Hirte HW. Profile of erlotinib and its potential in the treatment of advanced ovarian carcinoma. Onco Targets Ther 2013; 6:427-35. [PMID: 23723710 PMCID: PMC3665572 DOI: 10.2147/ott.s30373] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The epidermal growth-factor receptor (EGFR) is overexpressed in the majority of epithelial ovarian cancers and promotes cell proliferation, migration and invasion, and angiogenesis, as well as resistance to apoptosis. This makes EGFR an attractive therapeutic target in this disease. A number of strategies to block EGFR activity have been developed, including small-molecular-weight tyrosine kinase inhibitors such as erlotinib. Erlotinib has been evaluated as a single agent in recurrent ovarian cancer, as well as in combination with chemotherapeutic agents in the first-line and recurrent settings, and in combination with the antiangiogenic agent bevacizumab in the recurrent setting, as well as in the maintenance setting after completion of first-line chemotherapy. Unfortunately, erlotinib has shown only minimal efficacy as a single agent, and it has not enhanced the effects of chemotherapy or bevacizumab when combined with these agents. Ongoing and future studies of erlotinib and other agents blocking EGFR will need to define mechanisms resulting in resistance to such interventions, and to validate biomarkers of response to identify patients most likely to benefit from such approaches.
Collapse
Affiliation(s)
- Hal W Hirte
- Department of Oncology, McMaster University, Hamilton, ON, Canada
| |
Collapse
|
11
|
Chun YS, Oh HG, Park MK, Kim TW, Chung S. Increasing Membrane Cholesterol Level Increases the Amyloidogenic Peptide by Enhancing the Expression of Phospholipase C. JOURNAL OF NEURODEGENERATIVE DISEASES 2013; 2013:407903. [PMID: 26316988 PMCID: PMC4437359 DOI: 10.1155/2013/407903] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 12/09/2012] [Indexed: 11/24/2022]
Abstract
Cerebral elevation of 42-residue amyloid β-peptide (Aβ42) triggers neuronal dysfunction in Alzheimer's disease (AD). Even though a number of cholesterol modulating agents have been shown to affect Aβ generation, the role of cholesterol in the pathogenesis of AD is not clear yet. Recently, we have shown that increased membrane cholesterol levels downregulates phosphatidylinositol 4,5-bisphosphate (PIP2) via activation of phospholipase C (PLC). In this study, we tested whether membrane cholesterol levels may affect the Aβ42 production via changing PIP2 levels. Increasing membrane cholesterol levels decreased PIP2 and increased secreted Aβ42. Supplying PIP2, by using a PIP2-carrier system, blocked the effect of cholesterol on Aβ42. We also found that cholesterol increased the expressions of β1 and β3 PLC isoforms (PLCβ1, PLCβ3). Silencing the expression of PLCβ1 prevented the effects of cholesterol on PIP2 levels as well as on Aβ42 production, suggesting that increased membrane cholesterol levels increased secreted Aβ42 by downregulating PIP2 via enhancing the expression of PLCβ1. Thus, cholesterol metabolism may be linked to Aβ42 levels via PLCβ1 expression and subsequent changes in PIP2 metabolism.
Collapse
Affiliation(s)
- Yoon Sun Chun
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
| | - Hyun Geun Oh
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
| | - Myoung Kyu Park
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
| | - Tae-Wan Kim
- Department of Pathology, Columbia University Medical Center, New York, NY 10032, USA
| | - Sungkwon Chung
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
| |
Collapse
|
12
|
Reichenberger EJ, Levine MA, Olsen BR, Papadaki ME, Lietman SA. The role of SH3BP2 in the pathophysiology of cherubism. Orphanet J Rare Dis 2012; 7 Suppl 1:S5. [PMID: 22640988 PMCID: PMC3359958 DOI: 10.1186/1750-1172-7-s1-s5] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cherubism is a rare bone dysplasia that is characterized by symmetrical bone resorption limited to the jaws. Bone lesions are filled with soft fibrous giant cell-rich tissue that can expand and cause severe facial deformity. The disorder typically begins in children at ages of 2-5 years and the bone resorption and facial swelling continues until puberty; in most cases the lesions regress spontaneously thereafter. Most patients with cherubism have germline mutations in the gene encoding SH3BP2, an adapter protein involved in adaptive and innate immune response signaling. A mouse model carrying a Pro416Arg mutation in SH3BP2 develops osteopenia and expansile lytic lesions in bone and some soft tissue organs. In this review we discuss the genetics of cherubism, the biological functions of SH3BP2 and the analysis of the mouse model. The data suggest that the underlying cause for cherubism is a systemic autoinflammatory response to physiologic challenges despite the localized appearance of bone resorption and fibrous expansion to the jaws in humans.
Collapse
Affiliation(s)
- Ernst J Reichenberger
- Department of Reconstructive Sciences, Center for Regenerative Medicine and Skeletal Development, University of Connecticut Health Center, Farmington, CT, USA.
| | | | | | | | | |
Collapse
|
13
|
Xu L, Zhang Y, Liu J, Qu J, Hu X, Zhang F, Zheng H, Qu X, Liu Y. TRAIL-activated EGFR by Cbl-b-regulated EGFR redistribution in lipid rafts antagonises TRAIL-induced apoptosis in gastric cancer cells. Eur J Cancer 2012; 48:3288-99. [PMID: 22456178 DOI: 10.1016/j.ejca.2012.03.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/17/2012] [Accepted: 03/03/2012] [Indexed: 12/30/2022]
Abstract
Most gastric cancer cells are resistant to tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Since TRAIL resistance is associated with lipid rafts, in which both death receptors and epidermal growth factor receptors (EGFR) are enriched, our aim is to identify how lipid raft-regulated receptor redistribution influences the sensitivity of TRAIL in gastric cancer cells. In TRAIL-resistant gastric cancer cells, TRAIL did not induce effective death-inducing signalling complex (DISC) formation in lipid rafts, accompanied with EGFR translocation into lipid rafts, and activation of EGFR pathway. Knockdown of casitas B-lineage lymphoma-b (Cbl-b) enhanced TRAIL-induced apoptosis by promoting DISC formation in lipid rafts. However, knockdown of Cbl-b also enhanced EGFR translocation into lipid rafts and EGFR pathway activation induced by TRAIL. Either using inhibitors of EGFR or depletion of EGFR with small interfering RNA (siRNA) prevented EGFR pathway activation, and thus increased TRAIL-induced apoptosis, especially in Cbl-b knockdown clones. Taken together, TRAIL-induced EGFR activation through Cbl-b-regulated EGFR redistribution in lipid rafts antagonised TRAIL-induced apoptosis. The contribution of DISC formation and the inhibition of EGFR signal triggered in lipid rafts are both essential for increasing the sensitivity of gastric cancer cells to TRAIL.
Collapse
Affiliation(s)
- Ling Xu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang 110001, China
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Irwin ME, Bohin N, Boerner JL. Src family kinases mediate epidermal growth factor receptor signaling from lipid rafts in breast cancer cells. Cancer Biol Ther 2011; 12:718-26. [PMID: 21775822 DOI: 10.4161/cbt.12.8.16907] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Activation of the epidermal growth factor receptor (EGFR) regulates cellular proliferation, survival, and migration of breast cancer cells. In particular, EGFR recruits signaling proteins to the cell membrane leading to their phosphorylation and activation. However, EGFR also localizes to other cellular structures, including endosomes, mitochondrion, and nuclei. Recently, we demonstrated that lipid raft localization of EGFR in triple-negative breast cancer cell lines promotes EGFR protein-dependent, EGFR kinase-independent activation of Akt. Here, we further define the mechanism by which lipid rafts regulate EGFR signaling to Akt. Specifically, we show that the non-receptor tyrosine kinase c-Src co-localizes and co-associates with EGFR and lipid rafts. Breast cancer cells resistant to treatment with EGFR inhibitors, were also resistant to treatment with Src family kinase (SFK) inhibitors; however, the combination of EGFR and SFK inhibitors synergistically decreases cell viability. We found that this decrease in cell viability observed with EGFR and SFK inhibitor co-treatment correlates with loss of Akt phosphorylation. In addition, we found that in breast cancer cell lines with EGFR and c-Src co-localized to lipid rafts, phospho-inositide 3 kinase (PI3K) was also associated with lipid rafts. Together, the data herein suggest that lipid rafts provide a platform for the interaction of EGFR, c-Src, and PI3K, leading to activation of cellular survival signaling in breast cancer cells.
Collapse
Affiliation(s)
- Mary E Irwin
- Department of Pharmacology, Karmanos Cancer Institute, Wayne State University, Detroit, MI, USA
| | | | | |
Collapse
|
15
|
The effects of membrane compartmentalization of csk on TCR signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:367-76. [PMID: 21167217 DOI: 10.1016/j.bbamcr.2010.12.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 11/16/2010] [Accepted: 12/06/2010] [Indexed: 12/29/2022]
Abstract
The TCR signal transduction is initiated by the activation of Src-family kinases (SFK) which phosphorylate Immunoreceptor tyrosine-based activation motifs (ITAM) present in the intracellular parts of the T-cell receptor (TCR) signaling subunits. Numerous data suggest that after stimulation TCR interacts with membrane rafts and thus it gains access to SFK and other important molecules involved in signal transduction. However, the precise mechanism of this process is unclear. One of the key questions is how SFK access TCR and what is the importance of non-raft and membrane raft-associated SFK for the initiation and maintenance of the TCR signaling. To answer this question we targeted a negative regulator of SFK, C-terminal Src kinase (Csk) to membrane rafts, recently described "heavy rafts" or non-raft membrane. Our data show that only Csk targeted into "classical" raft but not to "heavy raft" or non-raft membrane effectively inhibits TCR signaling, demonstrating the critical role of membrane raft-associated SFK in this process.
Collapse
|
16
|
Thuringer D, Hammann A, Benikhlef N, Fourmaux E, Bouchot A, Wettstein G, Solary E, Garrido C. Transactivation of the epidermal growth factor receptor by heat shock protein 90 via Toll-like receptor 4 contributes to the migration of glioblastoma cells. J Biol Chem 2010; 286:3418-28. [PMID: 21127066 DOI: 10.1074/jbc.m110.154823] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Extracellular heat shock protein HSP90α was reported to participate in tumor cell growth, invasion, and metastasis formation through poorly understood signaling pathways. Herein, we show that extracellular HSP90α favors cell migration of glioblastoma U87 cells. More specifically, externally applied HSP90α rapidly induced endocytosis of EGFR. This response was accompanied by a transient increase in cytosolic Ca(2+) appearing after 1-3 min of treatment. In the presence of EGF, U87 cells showed HSP90α-induced Ca(2+) oscillations, which were reduced by the ATP/ADPase, apyrase, and inhibited by the purinergic P(2) inhibitor, suramin, suggesting that ATP release is requested. Disruption of lipid rafts with methyl β-cyclodextrin impaired the Ca(2+) rise induced by extracellular HSP90α combined with EGF. Specific inhibition of TLR4 expression by blocking antibodies suppressed extracellular HSP90α-induced Ca(2+) signaling and the associated cell migration. HSPs are known to bind lipopolysaccharides (LPSs). Preincubating cells with Polymyxin B, a potent LPS inhibitor, partially abrogated the effects of HSP90α without affecting Ca(2+) oscillations observed with EGF. Extracellular HSP90α induced EGFR phosphorylation at Tyr-1068, and this event was prevented by both the protein kinase Cδ inhibitor, rottlerin, and the c-Src inhibitor, PP2. Altogether, our results suggest that extracellular HSP90α transactivates EGFR/ErbB1 through TLR4 and a PKCδ/c-Src pathway, which induces ATP release and cytosolic Ca(2+) increase and finally favors cell migration. This mechanism could account for the deleterious effects of HSPs on high grade glioma when released into the tumor cell microenvironment.
Collapse
Affiliation(s)
- Dominique Thuringer
- INSERM U866, Faculty of Medicine, 7 Boulevard Jeanne d'Arc, 21000 Dijon, France.
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Kwiatkowska K. One lipid, multiple functions: how various pools of PI(4,5)P(2) are created in the plasma membrane. Cell Mol Life Sci 2010; 67:3927-46. [PMID: 20559679 PMCID: PMC11115911 DOI: 10.1007/s00018-010-0432-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 06/01/2010] [Accepted: 06/02/2010] [Indexed: 01/25/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)] is a minor lipid of the inner leaflet of the plasma membrane that controls the activity of numerous proteins and serves as a source of second messengers. This multifunctionality of PI(4,5)P(2) relies on mechanisms ensuring transient appearance of PI(4,5)P(2) clusters in the plasma membrane. One such mechanism involves phosphorylation of PI(4)P to PI(4,5)P(2) by the type I phosphatidylinositol-4-phosphate 5-kinases (PIP5KI) at discrete membrane locations coupled with PI(4)P delivery/synthesis at the plasma membrane. Simultaneously, both PI(4)P and PI(4,5)P(2) participate in anchoring PIP5KI at the plasma membrane via electrostatic bonds. PIP5KI isoforms are also selectively recruited and activated at the plasma membrane by Rac1, talin, or AP-2 to generate PI(4,5)P(2) in ruffles and lamellipodia, focal contacts, and clathrin-coated pits. In addition, PI(4,5)P(2) can accumulate at sphingolipid/cholesterol-based rafts following activation of distinct membrane receptors or be sequestered in a reversible manner due to electrostatic constrains posed by proteins like MARCKS.
Collapse
Affiliation(s)
- Katarzyna Kwiatkowska
- Laboratory of Plasma Membrane Receptors, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
| |
Collapse
|
18
|
Popa N, Cedile O, Pollet-Villard X, Bagnis C, Durbec P, Boucraut J. RAE-1 is expressed in the adult subventricular zone and controls cell proliferation of neurospheres. Glia 2010; 59:35-44. [DOI: 10.1002/glia.21074] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
19
|
Abstract
To determine the mechanism for the increased osteoclastogenesis in the jaw of cherubism patients with SH3BP2 mutations we evaluated the effect of mutant compared to wild-type SH3BP2 on activation of osteoclast signaling pathways. Indeed mutant forms of SH3BP2 do induce greater osteoclastogenesis. Heterozygous activating mutations in exon 9 of SH3BP2 have been found in most patients with cherubism, an unusual genetic syndrome characterized by excessive remodeling of the mandible and maxilla due to spontaneous and excessive osteoclastic bone resorption. Here we have investigated the functional consequences of SH3BP2 mutations on sRANKL-induced osteoclastogenesis in RAW 264.7 pre-osteoclast cells. sRANKL-stimulated RAW 264.7 cells were transfected with wild-type or mutant SH3BP2 plasmids. NFAT-luciferase and tartrate resistant acid phosphatase (TRAP), a marker of osteoclastic differentiation, levels were evaluated. Western immunoblots were also performed to determine phosphorylation of key proteins involved in the PI-PLC pathway leading to NFATc1 translocation. Our results indicate that forced expression of mutant forms of SH3BP2, found in cherubism patients, in RAW 264.7 cells induce greater NFAT activity and greater expression of TRAP than forced expression of wild-type SH3BP2. These findings indicate that missense SH3BP2 mutations cause a gain of protein function. Moreover, over expression of SH3BP2 in RAW 264.7 cells potentiates sRANKL-stimulated phosphorylation of PLCγ1 and PLCγ2. Our studies demonstrate that cherubism is due to gain-of-function mutations in SH3BP2 that stimulate RANKL-induced activation of PLCγ. The consequent activation of calcineurin and NFAT proteins induces the excessive osteoclastic phenotype of cherubism.
Collapse
Affiliation(s)
- Steven A. Lietman
- Department of Orthopaedic Surgery, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195
,Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195
| | - Lihong Yin
- Department of Orthopaedic Surgery, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195
,Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195
| | - Michael A. Levine
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195
,Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| |
Collapse
|
20
|
Modulation of brain-derived neurotrophic factor (BDNF) actions in the nervous system by adenosine A(2A) receptors and the role of lipid rafts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:1340-9. [PMID: 20603099 DOI: 10.1016/j.bbamem.2010.06.028] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 06/23/2010] [Accepted: 06/27/2010] [Indexed: 12/11/2022]
Abstract
In this paper we review some novel aspects related to the way adenosine A(2A) receptors (A(2A)R) modulate the action of BDNF or its high-affinity receptors, the TrkB receptors, on synaptic transmission and plasticity, as well as upon cholinergic currents and GABA transporters. Evidence has been accumulating that adenosine A(2A)Rs are required for most of the synaptic actions of BDNF. In some cases, where A(2A)Rs are constitutively activated (e.g. by endogenous extracellular adenosine), the need for A(2A)R activation for the maintenance of the synaptic influences of BDNF can be envisaged from the loss of BDNF effects upon blockade of adenosine A(2A)Rs or upon removal of extracellular adenosine with adenosine deaminase. In some other cases, it is necessary to enhance extracellular adenosine levels (e.g. depolarization) or to further activate A(2A)Rs (e.g. with selective agonists) to trigger a BDNF neuromodulatory role at the synapses. Age- and cell-dependent differences may determine the above two possibilities, but in all cases it is quite clear that there is close interplay between adenosine A(2A)Rs and BDNF TrkB receptors at synapses. The role of lipid rafts in this cross-talk will be discussed. This article is part of a Special Issue entitled: "Adenosine Receptors".
Collapse
|
21
|
Ohkawa Y, Miyazaki S, Hamamura K, Kambe M, Miyata M, Tajima O, Ohmi Y, Yamauchi Y, Furukawa K, Furukawa K. Ganglioside GD3 enhances adhesion signals and augments malignant properties of melanoma cells by recruiting integrins to glycolipid-enriched microdomains. J Biol Chem 2010; 285:27213-27223. [PMID: 20581115 DOI: 10.1074/jbc.m109.087791] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ganglioside GD3 is widely expressed in human malignant melanoma cell lines and tumors. Previously, we reported that GD3+ cells show stronger tyrosine phosphorylation of focal adhesion kinase (FAK), p130(Cas), and paxillin when treated with fetal calf serum than GD3- cells. In this study, we analyzed the changes in the signals mediated by the interaction between integrins and extracellular matrices (ECM) to clarify how GD3 enhances cell signals in the vicinity of the cell membrane. An adhesion assay with a real time cell electronic sensing system revealed that GD3+ cells had stronger adhesion to all extracellular matrices examined. In particular, GD3+ cells attached more strongly to collagen type I and type IV than controls. Correspondingly, they showed stronger tyrosine phosphorylation of FAK and paxillin during adhesion to collagen type I. In the floating pattern of detergent extracts, a high level of integrin beta1 was found in glycolipid-enriched microdomain (GEM)/rafts in GD3+ cells before adhesion, whereas a smaller amount of integrin beta1 was detected in the GEM/rafts of controls. Some phosphorylated forms of FAK as well as total FAK were found in GEM/rafts during cell adhesion only in GD3+ cells. Another signal consisting of integrin-linked kinase/Akt was also activated during adhesion more strongly in GD3+ cells than in controls. In double stained GD3+ cells, GD3 and integrin beta1 co-localized at the focal adhesion with a punctate pattern. All these results suggested that integrins assembled and formed a cluster in GEM/rafts, leading to the enhanced signaling and malignant properties under GD3 expression.
Collapse
Affiliation(s)
- Yuki Ohkawa
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065
| | - Sayaka Miyazaki
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065
| | - Kazunori Hamamura
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065
| | - Mariko Kambe
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan; Health Science Hills, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan
| | - Maiko Miyata
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan
| | - Orie Tajima
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065; Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan
| | - Yuhsuke Ohmi
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065
| | - Yoshio Yamauchi
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065
| | - Koichi Furukawa
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065.
| | - Keiko Furukawa
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065; Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan; Health Science Hills, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan.
| |
Collapse
|
22
|
Vitiello M, Finamore E, Raieta K, Kampanaraki A, Mignogna E, Galdiero E, Galdiero M. Cellular cholesterol involvement in Src, PKC, and p38/JNK transduction pathways by porins. J Interferon Cytokine Res 2010; 29:791-800. [PMID: 19929574 DOI: 10.1089/jir.2009.0010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Biological membranes are described as a mosaic of different domains where interactions between membrane components induce the formation of subdomains with different characteristics and functions. Lipids play an important role in the formation of lipid-enriched microdomains where they dynamically associate to form platforms important for membrane protein sorting and construction of signaling complexes. Cholesterol confined in lipid domains is a crucial component required by microorganisms, directly or indirectly, to enter or exit the intracellular compartment. Cellular activation mediated by superficial bacterial component may be modified by local cholesterol depletion. Therefore, new perspectives for unconventional therapeutic intervention in Gram-negative infections may be envisaged. We tested this hypothesis by using methyl-beta-cyclodextrin (mbetaCD) as a cholesterol-complexing agent to alter the U937 plasma membrane cholesterol content. Our results demonstrate that cholesterol depletion of U937 cells inhibited Salmonella enterica serovar Typhimurium porins-mediated phosphorylation of Src kinase family, protein kinase C (PKC), JNK, and p38, while cholesterol repletion restored the phosphorylation. Lipopolysaccharide (LPS) extracted from the same bacterial strain has been used as a control. Our data demonstrate that the lack of activation of signal transduction pathway observed following cholesterol depletion differently modulates the release of interleukin-6 (IL-6) or tumor necrosis factor-alpha (TNF-alpha), suggesting that Src, associated to lipid domains, may represent an important pathway in Gram-negative-induced cellular signal.
Collapse
Affiliation(s)
- Mariateresa Vitiello
- Department of Experimental Medicine, Section of Microbiology and Clinical Microbiology, Second University of Naples, Naples 80138, Italy
| | | | | | | | | | | | | |
Collapse
|
23
|
Targeting the epidermal growth factor receptor in epithelial ovarian cancer: current knowledge and future challenges. JOURNAL OF ONCOLOGY 2010; 2010:568938. [PMID: 20037743 PMCID: PMC2796463 DOI: 10.1155/2010/568938] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Accepted: 08/31/2009] [Indexed: 02/03/2023]
Abstract
The epidermal growth factor receptor is overexpressed in up to 60% of ovarian epithelial malignancies. EGFR regulates complex cellular events due to the large number of ligands, dimerization partners, and diverse signaling pathways engaged. In ovarian cancer, EGFR activation is associated with increased malignant tumor phenotype and poorer patient outcome. However, unlike some other EGFR-positive solid tumors, treatment of ovarian tumors with anti-EGFR agents has induced minimal response. While the amount of information regarding EGFR-mediated signaling is considerable, current data provides little insight for the lack of efficacy of anti-EGFR agents in ovarian cancer. More comprehensive, systematic, and well-defined approaches are needed to dissect the roles that EGFR plays in the complex signaling processes in ovarian cancer as well as to identify biomarkers that can accurately predict sensitivity toward EGFR-targeted therapeutic agents. This new knowledge could facilitate the development of rational combinatorial therapies to sensitize tumor cells toward EGFR-targeted therapies.
Collapse
|
24
|
Chun YS, Shin S, Kim Y, Cho H, Park MK, Kim TW, Voronov SV, Di Paolo G, Suh BC, Chung S. Cholesterol modulates ion channels via down-regulation of phosphatidylinositol 4,5-bisphosphate. J Neurochem 2009; 112:1286-94. [PMID: 20015154 DOI: 10.1111/j.1471-4159.2009.06545.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ubiquitously expressed Mg(2+)-inhibitory cation (MIC) channels are permeable to Ca2+ and Mg2+ and are essential for cell viability. When membrane cholesterol level was increased by pre-incubating cells with a water-soluble form of cholesterol, the endogenous MIC current in HEK293 cells was negatively regulated. The application of phosphatidylinositol 4,5-bisphosphate (PIP2) recovered MIC current from cholesterol effect. As PIP2 is the direct modulator for MIC channels, high cholesterol content may cause down-regulation of PIP2. To test this possibility, we examined the effect of cholesterol on two exogenously expressed PIP2-sensitive K+ channels: human Ether-a-go-go related gene (HERG) and KCNQ. Enrichment with cholesterol inhibited HERG currents, while inclusion of PIP2 in the pipette solution blocked the cholesterol effect. KCNQ channel was also inhibited by cholesterol. The effects of cholesterol on these channels were blocked by pre-incubating cells with inhibitors for phospholipase C, which may indicate that cholesterol enrichment induces the depletion of PIP2 via phospholipase C activation. Lipid analysis showed that cholesterol enrichment reduced gamma-(32)P incorporation into PIP2 by approximately 35%. Our results suggest that cholesterol may modulate ion channels by changing the levels of PIP2. Thus, an important cross-talk exists among two plasma membrane-enriched lipids, cholesterol and PIP2.
Collapse
Affiliation(s)
- Yoon Sun Chun
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Oldfield S, Hancock J, Mason A, Hobson SA, Wynick D, Kelly E, Randall AD, Marrion NV. Receptor-mediated suppression of potassium currents requires colocalization within lipid rafts. Mol Pharmacol 2009; 76:1279-89. [PMID: 19726551 DOI: 10.1124/mol.109.058008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Expression of KCNQ2/3 (Kv7.2 and -7.3) heteromers underlies the neuronal M current, a current that is suppressed by activation of a variety of receptors that couple to the hydrolysis of phosphatidylinositol 4,5-bisphosphate. Expression of Kv7.2/7.3 channels in human embryonic kidney (HEK) 293 cells produced a noninactivating potassium current characteristic of M current. Muscarinic receptors endogenous to HEK293 cells were identified as being M3 by pharmacology and Western blotting, producing a rise of intracellular calcium ([Ca2+](i)) upon activation. Activation of these endogenous muscarinic receptors however, failed to suppress expressed Kv7.2/7.3 current. Current suppression was reconstituted by coexpression of HA-tagged muscarinic m1 or m3 receptors. Examination of membrane fractions showed that both expressed receptors and Kv7.2 and -7.3 channel subunits resided within lipid rafts. Disruption of lipid rafts by pretreatment of cells expressing either m1 or m3 muscarinic receptors with methyl-beta-cyclodextrin produced a loss of localization of proteins within lipid raft membrane fractions. This pretreatment also abolished both the increase of [Ca2+](i) and suppression of expressed Kv7.2/7.3 current evoked by activation of expressed m1 or m3 muscarinic receptors. A similar loss of muscarinic receptor-mediated suppression of M current native to rat dorsal root ganglion neurons was observed after incubating dissociated cells with methyl-beta-cyclodextrin. These data suggested that lipid rafts colocalized both muscarinic receptors and channel subunits to enable receptor-mediated suppression of channel activity, a spatial colocalization that enables specificity of coupling between receptor and ion channel.
Collapse
Affiliation(s)
- Susan Oldfield
- Department of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, Bristol, BS81TD, UK
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Eum SY, Andras I, Hennig B, Toborek M. NADPH oxidase and lipid raft-associated redox signaling are required for PCB153-induced upregulation of cell adhesion molecules in human brain endothelial cells. Toxicol Appl Pharmacol 2009; 240:299-305. [PMID: 19632255 DOI: 10.1016/j.taap.2009.07.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2009] [Revised: 07/17/2009] [Accepted: 07/20/2009] [Indexed: 01/24/2023]
Abstract
Exposure to persistent organic pollutants, such as polychlorinated biphenyls (PCBs), can lead to chronic inflammation and the development of vascular diseases. Because cell adhesion molecules (CAMs) of the cerebrovascular endothelium regulate infiltration of inflammatory cells into the brain, we have explored the molecular mechanisms by which ortho-substituted polychlorinated biphenyls (PCBs), such as PCB153, can upregulate CAMs in brain endothelial cells. Exposure to PCB153 increased expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), as well as elevated adhesion of leukocytes to brain endothelial cells. These effects were impeded by inhibitors of EGFR, JAKs, or Src activity. In addition, pharmacological inhibition of NADPH oxidase or disruption of lipid rafts by cholesterol depleting agents blocked PCB153-induced phosphorylation of JAK and Src kinases and upregulation of CAMs. In contrast, silencing of caveolin-1 by siRNA interference did not affect upregulation of ICAM-1 and VCAM-1 in brain endothelial cells stimulated by PCB153. Results of the present study indicate that lipid raft-dependent NADPH oxidase/JAK/EGFR signaling mechanisms regulate the expression of CAMs in brain endothelial cells and adhesion of leukocytes to endothelial monolayers. Due to its role in leukocyte infiltration, induction of CAMs may contribute to PCB-induced cerebrovascular disorders and neurotoxic effects in the CNS.
Collapse
Affiliation(s)
- Sung Yong Eum
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536, USA.
| | | | | | | |
Collapse
|
27
|
Park Y, Kim KT. Dominant role of lipid rafts L-type calcium channel in activity-dependent potentiation of large dense-core vesicle exocytosis. J Neurochem 2009; 110:520-9. [PMID: 19457106 DOI: 10.1111/j.1471-4159.2009.06148.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Calcium influx triggers exocytosis by promoting vesicle fusion with the plasma membrane. However, different subtypes of voltage-gated calcium channel (VGCC) have distinct roles in exocytosis. We previously reported that repetitive stimulation induces activity-dependent potentiation (ADP) which represents the increase of neurotransmitter release. Here, we show that L-type VGCC have a dominant role in ADP of large dense-core vesicle (LDCV) exocytosis. Repetitive stimulation activating VGCC can induce ADP, whereas activation of bradykinin (BK) G protein-coupled receptors or purinergic P2X cation channels can not. L-type VGCC has the dominant role in ADP of LDCV exocytosis by regulating Protein Kinase C (PKC)-epsilon translocation and phosphorylation of myristoylated alanine-rich C kinase substrate (MARCKS), a target molecule of PKC-epsilon. We provide evidence that L-type VGCC, PKC-epsilon, and MARCKS, but not Q-type VGCC, are selectively located in lipid rafts. Also, PKC-epsilon translocation induced by L-type VGCC activation occurs in lipid rafts. Disruption of lipid rafts abolishes ADP of LDCV exocytosis and changes the fusion pore kinetics without affecting the first stimulation-induced exocytosis, showing that lipid rafts are involved in the potentiation process. Taken together, we suggest that L-type VGCC in lipid rafts selectively mediates ADP of LDCV exocytosis by regulating PKC-epsilon translocation and MARCKS phosphorylation.
Collapse
Affiliation(s)
- Yongsoo Park
- Department of Life Science, Pohang University of Science and Technology, Korea
| | | |
Collapse
|
28
|
Seong J, Lu S, Ouyang M, Huang H, Zhang J, Frame MC, Wang Y. Visualization of Src activity at different compartments of the plasma membrane by FRET imaging. ACTA ACUST UNITED AC 2009; 16:48-57. [PMID: 19171305 DOI: 10.1016/j.chembiol.2008.11.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 11/10/2008] [Accepted: 11/18/2008] [Indexed: 12/11/2022]
Abstract
Membrane compartments function as segregated signaling platforms for different cellular functions. It is not clear how Src is regulated at different membrane compartments. To visualize local Src activity in live cells, a FRET-based Src biosensor was targeted in or outside of lipid rafts at the plasma membrane, via acylation or prenylation modifications on targeting tags either directly fused to the biosensor or coupled to the biosensor through an inducible heterodimerization system. In response to growth factors and pervanadate, the induction of Src activity in rafts was slower and weaker, dependent on actin and possibly its mediated transportation of Src from perinuclear regions to the plasma membrane. In contrast, the induction of Src activity in nonrafts was faster and stronger, dependent on microtubules. Hence, Src activity is differentially regulated via cytoskeleton at different membrane compartments.
Collapse
Affiliation(s)
- Jihye Seong
- Neuroscience Program, Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | | | | | | | | | | | | |
Collapse
|
29
|
Pethő G, Reeh PW. Effects of Bradykinin on Nociceptors. NEUROGENIC INFLAMMATION IN HEALTH AND DISEASE 2009. [DOI: 10.1016/s1567-7443(08)10407-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
|
30
|
Johnson CM, Rodgers W. Spatial Segregation of Phosphatidylinositol 4,5-Bisphosphate (PIP(2)) Signaling in Immune Cell Functions. IMMUNOLOGY, ENDOCRINE & METABOLIC AGENTS IN MEDICINAL CHEMISTRY 2008; 8:349-357. [PMID: 19956793 PMCID: PMC2771939 DOI: 10.2174/187152208787169233] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP(2)) is a prevalent phosphoinositide in the inner leaflet of the plasma membrane. PIP(2) associates with an ever-growing list of proteins, and participates in a variety of cellular processes. PIP(2) signaling to the actin cytoskeleton transduces specific signals necessary for changes in morphology, motility, endocytosis, exocytosis, phagocytosis, and cell activation. The mechanism(s) by which PIP(2) signaling pathways are specific is a topic of intense investigation. One working model is the compartmentalization of PIP(2)-mediated signaling by concentrating PIP(2) in cholesterol-dependent membrane rafts, therefore providing spatial and temporal regulation. Here we discuss properties of PIP(2) signaling to the actin cytoskeleton in immune cell functioning, the association of PIP(2) cellular pools with membrane rafts, and recent work investigating models for compartmentalization of PIP(2)-mediated signaling in membrane rafts to the actin cytoskeleton.
Collapse
Affiliation(s)
- Corey M. Johnson
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation
| | - William Rodgers
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation
- Departments of Microbiology and Immunology, & Pathology, University of Oklahoma Health Sciences Center
| |
Collapse
|
31
|
Adachi T, Sato C, Kishi Y, Totani K, Murata T, Usui T, Kitajima K. Membrane microdomains from early gastrula embryos of medaka, Oryzias latipes, are a platform of E-cadherin- and carbohydrate-mediated cell-cell interactions during epiboly. Glycoconj J 2008; 26:285-99. [PMID: 18766437 DOI: 10.1007/s10719-008-9184-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Revised: 08/14/2008] [Accepted: 08/18/2008] [Indexed: 11/24/2022]
Abstract
Formation of membrane microdomain is critical for cell migration (epiboly) during gastrulation of medaka fish [Adachi et al. (Biochem. Biophys. Res. Commun. 358:848-853, 2007)]. In this study, we characterized membrane microdomain from gastrula embryos to understand its roles in epiboly. A cell adhesion molecule (E-cadherin), its associated protein (beta-catenin), transducer proteins (PLCgamma, cSrc), and a cytoskeleton protein (beta-actin) were enriched in the membrane microdomain. Le(X)-containing glycolipids and glycoproteins (Le(X)-gp) were exclusively enriched in the membrane microdomain. Interestingly, the isolated membrane microdomain had the ability to bind to each other in the presence of Ca(2+). This membrane microdomain binding was achieved through the E-cadherin homophilic and the Le(X)-glycan-mediated interactions. E-cadherin and Le(X)-gp were co-localized on the same membrane microdomain, suggesting that these two interactions are operative at the same time. Thus, the membrane microdomain functions as a platform of the E-cadherin- and Le(X)-glycan-mediated cell adhesion and signal transduction.
Collapse
Affiliation(s)
- Tomoko Adachi
- Bioscience and Biotechnology Center, Nagoya University, Nagoya, 464-8601, Japan
| | | | | | | | | | | | | |
Collapse
|
32
|
Lu S, Ouyang M, Seong J, Zhang J, Chien S, Wang Y. The spatiotemporal pattern of Src activation at lipid rafts revealed by diffusion-corrected FRET imaging. PLoS Comput Biol 2008; 4:e1000127. [PMID: 18711637 PMCID: PMC2517613 DOI: 10.1371/journal.pcbi.1000127] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 06/16/2008] [Indexed: 01/22/2023] Open
Abstract
Genetically encoded biosensors based on fluorescence resonance energy transfer (FRET) have been widely applied to visualize the molecular activity in live cells with high spatiotemporal resolution. However, the rapid diffusion of biosensor proteins hinders a precise reconstruction of the actual molecular activation map. Based on fluorescence recovery after photobleaching (FRAP) experiments, we have developed a finite element (FE) method to analyze, simulate, and subtract the diffusion effect of mobile biosensors. This method has been applied to analyze the mobility of Src FRET biosensors engineered to reside at different subcompartments in live cells. The results indicate that the Src biosensor located in the cytoplasm moves 4–8 folds faster (0.93±0.06 µm2/sec) than those anchored on different compartments in plasma membrane (at lipid raft: 0.11±0.01 µm2/sec and outside: 0.18±0.02 µm2/sec). The mobility of biosensor at lipid rafts is slower than that outside of lipid rafts and is dominated by two-dimensional diffusion. When this diffusion effect was subtracted from the FRET ratio images, high Src activity at lipid rafts was observed at clustered regions proximal to the cell periphery, which remained relatively stationary upon epidermal growth factor (EGF) stimulation. This result suggests that EGF induced a Src activation at lipid rafts with well-coordinated spatiotemporal patterns. Our FE-based method also provides an integrated platform of image analysis for studying molecular mobility and reconstructing the spatiotemporal activation maps of signaling molecules in live cells. Fluorescence biosensors have been widely used to report the spatial and temporal activity of target molecules in live cells. However, biosensors can move independently of the target molecule and carry its signal to other subcellular locations. Therefore, the observed images appear to be the combination of the target molecular activity and the artifacts introduced by the movement of the biosensors (mainly due to diffusion). The intriguing question is how to estimate and exclude the movement effect of biosensors from the observed fluorescent images and to reconstruct the real activity map of the target molecules. The Src molecule plays important roles in cell adhesion, migration, and cancer invasion. In this paper, we developed a novel computational method to analyze and simulate the movement of the Src biosensor, which was then subtracted from the original fluorescent images. With this computational method, we observed discrete clusters of high Src activity at relatively stationary locations on the plasma membrane. Therefore, our results highlight the coordination of molecular activities in space and time. In addition to Src, our computational method can be used to reconstruct the activity map of other signaling molecules.
Collapse
Affiliation(s)
- Shaoying Lu
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Mingxing Ouyang
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Jihye Seong
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
- Solomon H. Snyder Department of Neuroscience and Department of Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Shu Chien
- Department of Bioengineering, University of California at San Diego, San Diego, California, United States of America
- Department of Medicine, University of California at San Diego, San Diego, California, United States of America
| | - Yingxiao Wang
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Beckman Institute for Advanced Science and Technology, Department of Molecular and Integrative Physiology and Center of Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
| |
Collapse
|
33
|
Lietman SA, Yin L, Levine MA. SH3BP2 is an activator of NFAT activity and osteoclastogenesis. Biochem Biophys Res Commun 2008; 371:644-8. [PMID: 18440306 DOI: 10.1016/j.bbrc.2008.04.080] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Accepted: 04/11/2008] [Indexed: 10/22/2022]
Abstract
Heterozygous activating mutations in exon 9 of SH3BP2 have been found in most patients with cherubism, an unusual genetic syndrome characterized by excessive remodeling of the mandible and maxilla due to spontaneous and excessive osteoclastic bone resorption. Osteoclasts differentiate after binding of sRANKL to RANK induces a number of downstream signaling effects, including activation of the calcineurin/NFAT (nuclear factor of activated T cells) pathway. Here, we have investigated the functional significance of SH3BP2 protein on osteoclastogenesis in the presence of sRANKL. Our results indicate that SH3BP2 both increases nuclear NFATc1 in sRANKL treated RAW 264.7 preosteoclast cells and enhances expression of tartrate resistant acid phosphatase (TRAP), a specific marker of osteoclast differentiation. Moreover, overexpression of SH3BP2 in RAW 264.7 cells potentiates sRANKL-stimulated phosphorylation of PLCgamma1 and 2, thus providing a mechanistic pathway for the rapid translocation of NFATc1 into the nucleus and increased osteoclastogenesis in cherubism.
Collapse
Affiliation(s)
- Steven A Lietman
- Department of Orthopaedic Surgery, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
| | | | | |
Collapse
|
34
|
Róg T, Murzyn K, Karttunen M, Pasenkiewicz-Gierula M. Nonpolar interactions between trans-membrane helical EGF peptide and phosphatidylcholines, sphingomyelins and cholesterol. Molecular dynamics simulation studies. J Pept Sci 2008; 14:374-82. [DOI: 10.1002/psc.936] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
35
|
de Diesbach P, Medts T, Carpentier S, D'Auria L, Van Der Smissen P, Platek A, Mettlen M, Caplanusi A, van den Hove MF, Tyteca D, Courtoy PJ. Differential subcellular membrane recruitment of Src may specify its downstream signalling. Exp Cell Res 2008; 314:1465-79. [DOI: 10.1016/j.yexcr.2008.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 12/21/2007] [Accepted: 01/14/2008] [Indexed: 12/22/2022]
|
36
|
Tanikawa R, Tanikawa T, Okada Y, Nakano K, Hirashima M, Yamauchi A, Hosokawa R, Tanaka Y. Interaction of galectin-9 with lipid rafts induces osteoblast proliferation through the c-Src/ERK signaling pathway. J Bone Miner Res 2008; 23:278-86. [PMID: 17907924 DOI: 10.1359/jbmr.071008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED Galectin-9 is a beta-galactoside-binding lectin expressed in various tissues, including bone. The role of galectin-9 in human osteoblasts, however, remains unclear. This study showed that galectin-9 interacts with lipid rafts and induces osteoblast proliferation through the c-Src/ERK signaling pathway. INTRODUCTION Galectin-9 is a beta-galactoside-binding lectin that modulates many biological functions by interacting with particular carbohydrates attached to proteins and lipids. However, the role of galectin-9 in bone metabolism and osteoblast proliferation remains unclear. This study investigated the effects of galectin-9 on osteoblast proliferation and its signaling mechanisms. MATERIALS AND METHODS The effect of galectin-9 on osteoblast proliferation was tested by measuring the conversion of tetrazolium salt WST-8 to formazan. Protein phosphorylation was assayed by western blotting and confocal microscopy was used to localize lipid rafts. RESULTS Galectin-9-induced proliferation of the obtained osteoblasts in a dose-dependent manner, whereas galectin-1, -3, and -4 did not. Galectin-9-induced phosphorylation of c-Src and subsequent ERK1/ERK2 in the osteoblasts. The galectin-9-induced phosphorylation and proliferation were inhibited by PP2, a selective inhibitor of c-Src. Galectin-9-induced clustering of lipid rafts detected by cholera toxin B (CTB; binding the raft-resident ganglioside GM1) using confocal microscopy. Cross-linking of the GM1 ganglioside with CTB by anti-CTB antibody-induced phosphorylation of c-Src, whereas disruption of galectin-9-induced lipid rafts by beta-methylcyclodextrin reduced c-Src phosphorylation and proliferation of the cells. CONCLUSIONS These results suggest that galectin-9, but not other galectins, induced proliferation of human osteoblasts through clustering lipid rafts on membrane and subsequent phosphorylation of the c-Src/ERK signaling pathway.
Collapse
Affiliation(s)
- Rena Tanikawa
- First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Kitakyushu, Japan
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Yano N, Suzuki D, Endoh M, Zhao TC, Padbury JF, Tseng YT. A novel phosphoinositide 3-kinase-dependent pathway for angiotensin II/AT-1 receptor-mediated induction of collagen synthesis in MES-13 mesangial cells. J Biol Chem 2007; 282:18819-30. [PMID: 17493931 DOI: 10.1074/jbc.m610537200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Chronic activation of the angiotensin II (ANG II) type 1 receptor (AT-1R) is critical in the development of chronic kidney disease. ANG II activates mesangial cells (MCs) and stimulates the synthesis of extracellular matrix components. To determine the molecular mechanisms underlying the induction of MC collagen, a mouse mesangial cell line MES-13 was employed. ANG II treatment induced an increase in collagen synthesis, which was abrogated by co-treatment with losartan (an AT-1R antagonist), wortmannin (a phosphoinositide 3-kinase (PI3K) inhibitor), an Akt inhibitor, and stable transfection of dominant negative-Akt1. ANG II induced a significant increase in PI3K activity, which was abolished by co-treatment with losartan or 2',5'-dideoxyadenosine (2',5'-DOA, an adenylyl cyclase inhibitor) but not by PD123319 (an AT-2R antagonist) or H89 (a protein kinase A (PKA) inhibitor). The Epac (exchange protein directly activated by cAMP)-specific cAMP analog, 8-pHPT-2'-O-Me-cAMP, significantly increased PI3K activity, whereas a PKA-specific analog, 6-benzoyladenosine-cAMP, showed no effect. The ANG II-induced increase in PI3K activity was also blocked by co-treatment with PP2, an Src inhibitor, or AG1478, an epidermal growth factor receptor (EGFR) antagonist. ANG II induced phosphorylation of Akt and p70S6K and EGFR, which was abrogated by knockdown of c-Src by small interference RNA. Knockdown of Src also effectively abolished ANG II-induced collagen synthesis. Conversely, stable transfection of a constitutively active Src mutant enhanced basal PI3K activity and collagen production, which was abrogated by AG1478 but not by 2',5'-DOA. Moreover, acute treatment with ANG II significantly increased Src activity, which was abrogated with co-treatment of 2',5'-DOA. Taken together, these results suggest that ANG II induces collagen synthesis in MCs by activating the ANG II/AT-1R-EGFR-PI3K pathway. This transactivation is dependent on cAMP/Epac but not on PKA. Src kinase plays a pivotal role in this signaling pathway between cAMP and EGFR. This is the first demonstration that an AT1R-PI3K/Akt crosstalk, along with transactivation of EGFR, mediates ANG II-induced collagen synthesis in MCs.
Collapse
Affiliation(s)
- Naohiro Yano
- Department of Pediatrics, Women and Infant's Hospital, The Warren Alpert Medical School, Brown University, Providence, Rhode Island 02905, USA
| | | | | | | | | | | |
Collapse
|
38
|
Hienola A, Tumova S, Kulesskiy E, Rauvala H. N-syndecan deficiency impairs neural migration in brain. ACTA ACUST UNITED AC 2006; 174:569-80. [PMID: 16908672 PMCID: PMC2064262 DOI: 10.1083/jcb.200602043] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
N-syndecan (syndecan-3) is a transmembrane proteoglycan that is abundantly expressed in the major axonal pathways and in the migratory routes of the developing brain. When ligated by heparin-binding (HB) growth-associated molecule (GAM; pleiotrophin), N-syndecan mediates cortactin-Src kinase-dependent neurite outgrowth. However, the functional role of N-syndecan in brain development remains unexplored. In this study, we show that N-syndecan deficiency perturbs the laminar structure of the cerebral cortex as a result of impaired radial migration. In addition, neural migration in the rostral migratory stream is impaired in the N-syndecan-null mice. We suggest that the migration defect depends on impaired HB-GAM-induced Src kinase activation and haptotactic migration. Furthermore, we show that N-syndecan interacts with EGF receptor (EGFR) at the plasma membrane and is required in EGFR-induced neuronal migration.
Collapse
Affiliation(s)
- Anni Hienola
- Neuroscience Center, University of Helsinki, 00014 Helsinki, Finland.
| | | | | | | |
Collapse
|
39
|
Drube S, Stirnweiss J, Valkova C, Liebmann C. Ligand-independent and EGF receptor-supported transactivation: Lessons from β2-adrenergic receptor signalling. Cell Signal 2006; 18:1633-46. [PMID: 16495036 DOI: 10.1016/j.cellsig.2006.01.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 01/11/2006] [Indexed: 12/31/2022]
Abstract
Transactivation of epidermal growth factor receptor (EGFR) by G protein-coupled receptors (GPCRs) is currently understood to be mediated by matrix metalloproteases (MMPs) and the release of EGF-like ligands. This ligand-mediated process also suggests that downstream of EGFR the signalling in response to GPCR ligands or EGF appears to be indistinguishable. Here we provide evidence that transactivation of EGFR by the beta2-adrenergic receptor (beta2-AR) is independent of MMPs and results in an incomplete downstream signalling involving extracellular signal-activated kinase (ERK) but not PLCgamma1 and Akt. In contrast, beta2-AR has the ability to activate PLCgamma1 when the EGFR is primed either by co-stimulation with EGF or by increased basal activity due to over-expression. In that way but not via the beta2-AR-mediated transactivation the EGFR docking sites pY992 and pY1173 may be generated which are critical for PLCgamma1. This EGFR-supported transactivation is strongly dependent on EGFR tyrosine kinase, c-Src, and the c-Src-specific EGFR tyrosine residue 845 and represents a novel paradigm of EGFR transactivation.
Collapse
Affiliation(s)
- Sebastian Drube
- Institute of Biochemistry and Biophysics, Biological and Pharmaceutical Faculty, Friedrich-Schiller-University Jena, Philosophenweg 12, D-07743 Jena, Germany
| | | | | | | |
Collapse
|
40
|
Mojsilovic-Petrovic J, Jeong GB, Crocker A, Arneja A, David S, Russell D, Kalb RG. Protecting motor neurons from toxic insult by antagonism of adenosine A2a and Trk receptors. J Neurosci 2006; 26:9250-63. [PMID: 16957081 PMCID: PMC6674510 DOI: 10.1523/jneurosci.1856-06.2006] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The death of motor neurons in amyotrophic lateral sclerosis (ALS) is thought to result from the interaction of a variety of factors including excitotoxicity, accumulation of toxic proteins, and abnormal axonal transport. Previously, we found that the susceptibility of motor neurons to excitotoxic insults can be limited by inhibiting signals evoked by brain-derived neurotrophic factor (BDNF) activation of the receptor tyrosine kinase B (TrkB). Here we show that this can be achieved by direct kinase inhibition or by blockade of a transactivation pathway that uses adenosine A2a receptors and src-family kinases (SFKs). Downstream signaling cascades (such as mitogen-activated protein kinase and phosphatidylinositol-3 kinase) are inhibited by these blockers. In addition to protecting motor neurons from excitotoxic insult, these agents also prevent toxicity that follows from the expression of mutant proteins (G85R superoxide dismutase 1; G59S p150(glued)) that cause familial motor neuron disease. TrkB, adenosine A2a receptors, and SFKs associate into complexes in lipid raft and nonlipid raft membranes and the signaling from lipids rafts may be particularly important because their disruption by cholesterol depletion blocks the ability of BDNF to render motor neurons vulnerable to insult. The neuroprotective versatility of Trk antagonism suggests that it may have broad utility in the treatment of ALS patients.
Collapse
Affiliation(s)
- Jelena Mojsilovic-Petrovic
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| | - Goo-Bo Jeong
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
- Department of Anatomy, College of Medicine, Chungbuk National University, Cheong-ju 361-763, Republic of Korea, and
| | - Amanda Crocker
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| | - Amrita Arneja
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| | - Samuel David
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| | - David Russell
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06519
| | - Robert G. Kalb
- Department of Neurology, Children’s Hospital of Philadelphia, Joseph Stokes Jr. Research Institute, Philadelphia, Pennsylvania 19104
| |
Collapse
|
41
|
Liu X, Jefcoate C. 2,3,7,8-tetrachlorodibenzo-p-dioxin and epidermal growth factor cooperatively suppress peroxisome proliferator-activated receptor-gamma1 stimulation and restore focal adhesion complexes during adipogenesis: selective contributions of Src, Rho, and Erk distinguish these overlapping processes in C3H10T1/2 cells. Mol Pharmacol 2006; 70:1902-15. [PMID: 16971554 DOI: 10.1124/mol.106.026534] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stimulation of PPARgamma1 and adipogenesis in multipotential C3H10T1/2 cells by the combination of dexamethasone and 3-isobutyl-1-methylxanthine (DM) is suppressed by 2,3,7,8 tetrachlorodibenzodioxin (TCDD) (10 nM). This suppression requires sustained activation of extracellular signal-regulated kinase (Erk)1/2. We show that it arises from an effect of TCDD on epidermal growth factor (EGF) signaling. DM initiates an early loss of cell adhesion that is reversed by this TCDD/EGF synergy. Src kinase activity was completely essential for adhesion restoration, sustained Erk activation, and suppression of peroxisome proliferator-activated receptor (PPAR)gamma1. MEK/Erk activity did not contribute, however, to TCDD-induced adhesion. Stimulation of adhesion may therefore precede elevation of Erk. Adhesion is produced by interaction of alphabeta integrins with extracellular matrix proteins and subsequent Src-mediated phosphorylation of focal adhesion kinase (FAK, Tyr576/577) and paxillin (Tyr118). TCDD enhanced the steady state Src-mediated phosphorylation of FAK but not of paxillin. Protein tyrosine phosphatase (PTPase) inhibition by orthovanadate (OVA) showed that this Src activity is highly restricted by PTPases. Partial inhibition of PTPases by OVA mimicked TCDD in producing EGF- and Src-dependent effects on cell adhesion and PPARgamma1 suppression. TCDD may therefore induce a protein that enhances Src effectiveness at adhesion sites. Rho kinase (ROCK) inhibition blocked TCDD/EGF stimulation of clustered focal adhesion complexes without affecting either sustained Erk activation or suppression of PPARgamma1. Thus, this ROCK-mediated clustering of integrin complexes is not needed for the effects of TCDD on Erk and PPARgamma1. A minimal cholesterol depletion with beta-methylcyclodextrin attenuated TCDD effects on PPARgamma1 and Erk activation. TCDD intervention is therefore linked to extracellular proteins. It indicates that TCDD-enhanced stimulation of EGF signaling to Erk may derive from the initial alphabeta integrin complexes.
Collapse
Affiliation(s)
- Xueqing Liu
- Department of Pharmacology, Medical Science Center, University of Wisconsin-Madison, 1300 University Ave., Madison, WI 53706, USA
| | | |
Collapse
|
42
|
Igarashi J, Miyoshi M, Hashimoto T, Kubota Y, Kosaka H. Hydrogen peroxide induces S1P1 receptors and sensitizes vascular endothelial cells to sphingosine 1-phosphate, a platelet-derived lipid mediator. Am J Physiol Cell Physiol 2006; 292:C740-8. [PMID: 16943246 DOI: 10.1152/ajpcell.00117.2006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sphingosine 1-phosphate (S1P) is a platelet-derived angiogenic lipid growth factor, modulating G-protein-coupled S1P(1) receptors (S1P(1)-R) to activate endothelial nitric oxide synthase (eNOS), as well as MAPK pathways in endothelial cells. We explored whether and how hydrogen peroxide (H(2)O(2)), a representative reactive oxygen species, alters S1P(1)-R expression and influences S1P signaling in cultured bovine aortic endothelial cells (BAECs). When BAECs are treated with pathophysiologically relevant concentrations of H(2)O(2) (150 microM for 30 min), S1P(1)-R protein expression levels are acutely augmented by approximately 30-fold in a dose-dependent fashion. When BAECs have been pretreated with H(2)O(2), subsequent S1P stimulation (100 nM) leads to a higher degree of eNOS enzyme activation (assessed as intracellular cGMP content, 1.7 +/- 0.2-fold vs. no H(2)O(2) pretreatment groups, P < 0.05), associated with a higher magnitude of phosphorylation responses of eNOS and MAPK ERK1/2. PP2, an inhibitor of Src-family tyrosine kinase, abolished the effects of H(2)O(2) on both S1P(1)-R protein upregulation and enhanced BAEC responses to S1P. H(2)O(2) does not augment S1P(1) mRNA expression, whereas VEGF under identical cultures leads to increases in S1P(1) mRNA signals. Whereas H(2)O(2) attenuates proliferation of BAECs, addition of S1P restores growth responses of these cells. These results demonstrate that extracellularly administered H(2)O(2) increases S1P(1)-R expression and promotes endothelial responses for subsequent S1P treatment. These results may identify potentially important points of cross-talk between reactive oxygen species and sphingolipid pathways in vascular responses.
Collapse
Affiliation(s)
- Junsuke Igarashi
- Dept. of Cardiovascular Physiology, Kagawa Univ. Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793 Japan.
| | | | | | | | | |
Collapse
|
43
|
Lakshmi S, Joshi PG. Activation of Src/kinase/phospholipase C/mitogen-activated protein kinase and induction of neurite expression by ATP, independent of nerve growth factor. Neuroscience 2006; 141:179-89. [PMID: 16730415 DOI: 10.1016/j.neuroscience.2006.03.074] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 03/27/2006] [Accepted: 03/29/2006] [Indexed: 12/18/2022]
Abstract
Extracellular ATP has been reported to potentiate the neurite outgrowth induced by nerve growth factor. In the present study the neurotrophic effect of ATP and other nucleotides was examined in mouse neuroblastoma neuro2a cells which lack nerve growth factor receptor. Exposure of neuro2a cells to ATP resulted in a dramatic increase in neurite bearing cells as compared with untreated control cells. Experiments performed with purinergic receptor agonists and antagonists suggest that the ATP stimulates neurite outgrowth via P2 receptors. Neurite outgrowth was completely blocked by P2 receptor antagonist suramin whereas the P1 receptor antagonist CGS15943 was ineffective. P1 receptor agonist 5'-(N-ethylcarboxamido)adenosine failed to induce neurite outgrowth. The potency order of different P2 receptor agonists was ATP=ATPgammaS>ADP>>2Me-S-ATP. It was insensitive to UTP and antagonist pyridoxal phosphate-6-azo (benzene-2,4-disulfonic acid) suggesting the involvement of P2Y11 receptor in the observed neuritogenic effect. The signaling pathway leading to ATP-induced neuritogenesis was investigated. The neuritogenic effect of ATP is independent of rise in intracellular Ca(2+) as pharmacological profile of neuritogenic P2Y receptor does not match with that of P2Y2 receptor associated with [Ca(2+)](i) signaling cascade. Exposure of cells to ATP caused activation of Src kinase, phospholipase Cgamma and extracellular signal-regulated kinases ERK1/2. Mitogen-activated protein kinase (MAPK) inhibitor U0126 drastically reduced the number of neurite bearing cells in ATP-treated cultures implying that the neurotrophic effect of ATP is mediated by MAPK. Our results demonstrate that ATP can stimulate neurite outgrowth independent of other neurotrophic factors and can be an effective trophic agent.
Collapse
Affiliation(s)
- S Lakshmi
- Department of Biophysics, National Institute of Mental Health and Neurosciences, Bangalore 560 029, India
| | | |
Collapse
|
44
|
de Chastellier C, Thilo L. Cholesterol depletion in Mycobacterium avium-infected macrophages overcomes the block in phagosome maturation and leads to the reversible sequestration of viable mycobacteria in phagolysosome-derived autophagic vacuoles. Cell Microbiol 2006; 8:242-56. [PMID: 16441435 DOI: 10.1111/j.1462-5822.2005.00617.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phagocytic entry of mycobacteria into macrophages requires the presence of cholesterol in the plasma membrane. This suggests that pathogenic mycobacteria may require cholesterol for their subsequent intra-cellular survival in non-maturing phagosomes. Here we report on the effect of cholesterol depletion on pre-existing phagosomes in mouse bone marrow-derived macrophages infected with Mycobacterium avium. Cholesterol depletion with methyl-beta-cyclodextrin resulted in a loosening of the close apposition between the phagosome membrane and the mycobacterial surface, followed by fusion with lysosomes. The resulting phagolysosomes then autonomously executed autophagy, which did not involve the endoplasmic reticulum. After 5 h of depletion, intact mycobacteria had accumulated in large auto-phagolysosomes. Autophagy was specific for phagolysosomes that contained mycobacteria, as it did not involve latex bead-containing phagosomes in infected cells. Upon replenishment of cholesterol, mycobacteria became increasingly aligned to the lysosomal membrane, from where they were individually sequestered in phagosomes with an all-around closely apposed phagosome membrane and which no longer fused with lysosomes. These observations indicate that, cholesterol depletion (i) resulted in phagosome maturation and fusion with lysosomes and (ii) caused mycobacterium-containing phagolysosomes to autonomously undergo autophagy. Furthermore, (iii) mycobacteria were not killed in auto-phagolysosomes, and (iv) cholesterol replenishment enabled mycobacterium to rescue itself from autophagic phagolysosomes to again reside individually in phagosomes which no longer fused with lysosomes.
Collapse
Affiliation(s)
- Chantal de Chastellier
- Centre d'Immunologie de Marseille-Luminy, INSERM-CNRS-Université de la Méditerranée, Marseille, France.
| | | |
Collapse
|
45
|
Kim JH, Kim HW, Jeon H, Suh PG, Ryu SH. Phospholipase D1 regulates cell migration in a lipase activity-independent manner. J Biol Chem 2006; 281:15747-56. [PMID: 16608858 DOI: 10.1074/jbc.m509844200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell migration, a complex biological process, requires dynamic cytoskeletal remodeling. Phospholipase D (PLD) generates phosphatidic acid, a lipid second messenger. Although PLD activity has been proposed to play a role in cytoskeletal rearrangement, the manner in which PLD participates in the rearrangement process remains obscure. In this study, by silencing endogenous PLD isozymes using small interfering RNA in HeLa cells, we demonstrate that endogenous PLD1 is required for the normal organization of the actin cytoskeleton, and, more importantly, for cell motility. PLD1 silencing in HeLa cells resulted in dramatic changes in cellular morphology, including the accumulation of stress fibers, as well as cell elongation and flattening, which appeared to be caused by an increased number of focal adhesions, which ultimately culminated in enhanced cell-substratum interactions. Accordingly, serum-induced cell migration was profoundly inhibited by PLD1-silencing. Moreover, the augmented cell substratum interaction and retarded cell migration induced by PLD1-silencing could be restored by the adding back not only of wild type, but also of lipase-inactive PLD1 into knockdown cells. Taken together, our results strongly suggest that endogenous PLD1 is a critical factor in the organization of the actin-based cytoskeleton, with regard to cell adhesion and migration. These effects of PLD1 appear to operate in a lipase activity-independent manner. We also discuss the regulation of Src family kinases by PLD1, as related to the modulation of Pyk2 and cell migration.
Collapse
Affiliation(s)
- Jung Hwan Kim
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, South Korea
| | | | | | | | | |
Collapse
|
46
|
Park YS, Jun DJ, Hur EM, Lee SK, Suh BS, Kim KT. Activity-dependent potentiation of large dense-core vesicle release modulated by mitogen-activated protein kinase/extracellularly regulated kinase signaling. Endocrinology 2006; 147:1349-56. [PMID: 16306081 DOI: 10.1210/en.2005-0959] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Large dense-core vesicles (LDCVs), containing neuropeptides, hormones, and amines, play a crucial role in the activation of the sympathetic nervous system and synaptic modulation. In some secretory cells, LDCVs show activity-dependent potentiation (ADP), which represents enhancement of subsequent exocytosis, compared with the previous one. Here we report the signaling mechanism involved in ADP of LDCV release. First, ADP of LDCV release, induced by repetitive stimulation of nicotinic acetylcholine receptors (nAChRs), was augmented by increasing calcium influx, showing calcium dependence of ADP. Second, translocation of vesicles was involved in ADP. Electron microscope analysis revealed that nAChR stimulation resulted in LDCV translocation to the plasma membrane and increase of fused LDCVs in response to repetitive stimulation was observed by amperometry. Third, we provide evidence for involvement of MAPK signaling in ADP. MAPK signaling was activated by nAChR-induced calcium influx, and ADP as well as vesicle translocation was suppressed by inhibition of MAPK signaling with MAPK kinase blockers, such as PD 098059 and U0126. Fourth, PD 098059 inhibited nAChR stimulation-induced F-actin disassembly, which has been reported to control vesicle translocation. Taken together, we suggest that ADP of LDCV release is modulated by calcium-dependent activation of MAPK signaling via regulating F-actin disassembly.
Collapse
Affiliation(s)
- Yong-Soo Park
- Department of Life Science, Pohang University of Science and Technology, San 31, Hyoja Dong, Pohang 790-784, Republic of Korea
| | | | | | | | | | | |
Collapse
|
47
|
Riff JD, Callahan JW, Sherman PM. Cholesterol-enriched membrane microdomains are required for inducing host cell cytoskeleton rearrangements in response to attaching-effacing Escherichia coli. Infect Immun 2005; 73:7113-25. [PMID: 16239505 PMCID: PMC1273830 DOI: 10.1128/iai.73.11.7113-7125.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The diarrheal pathogens enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain CL56 and enteropathogenic Escherichia coli (EPEC) O127:H6 strain E2348/69 adhere intimately to epithelial cells through attaching-effacing lesions, which are characterized by rearrangements of the host cytoskeleton, intimate adherence, and destruction of microvilli. These cytoskeletal responses require activation of host signal transduction pathways. Lipid rafts are signaling microdomains enriched in sphingolipid and cholesterol in the plasma membrane. The effect of perturbing plasma membrane cholesterol on bacterial intimate adherence was assessed. Infection of both HEp-2 cells and primary skin fibroblasts with strains CL56 and E2348/69 caused characteristic rearrangements of the cytoskeleton at sites of bacterial adhesion. CL56- and E2348/69-induced cytoskeletal rearrangements were inhibited following cholesterol depletion. Addition of exogenous cholesterol to depleted HEp-2 cells restored cholesterol levels and rescued bacterially induced alpha-actinin mobilization. Quantitative bacterial adherence assays showed that EPEC adherence to HEp-2 cells was dramatically reduced following cholesterol depletion, whereas the adherence of EHEC remained high. Cytoskeletal rearrangements on skin fibroblasts obtained from children with Niemann-Pick type C disease were markedly reduced. These findings indicate that host membrane cholesterol contained in lipid rafts is necessary for the cytoskeletal rearrangements following infection with attaching-effacing Escherichia coli. Differences in initial adherence indicate divergent roles for host membrane cholesterol in the pathogenesis of EHEC and EPEC infections.
Collapse
Affiliation(s)
- Jason D Riff
- Research Institute, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
| | | | | |
Collapse
|
48
|
Schlemper V, Medeiros R, Ferreira J, Campos MM, Calixto JB. Mechanisms underlying the relaxation response induced by bradykinin in the epithelium-intact guinea-pig trachea in vitro. Br J Pharmacol 2005; 145:740-50. [PMID: 15852038 PMCID: PMC1576187 DOI: 10.1038/sj.bjp.0706222] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In this study, we investigated some of the signalling pathways involved in bradykinin (BK)-induced relaxation in epithelium-intact strips of the guinea-pig trachea (GPT + E). BK induced time- and concentration-dependent relaxation of GPT + E. Similar responses were observed for prostaglandin E2 (PGE2) or the combination of subthreshold concentrations of BK plus PGE2. The nonselective cyclooxygenase (COX) inhibitors indomethacin or pyroxicam, or the selective COX-2 inhibitors DFU, NS 398 or rofecoxib, but not the selective COX-1 inhibitor SC 560, all abolished BK-induced relaxation. The tyrosine kinase inhibitors herbimycin A and AG 490 also abolished BK-induced relaxation in GPT + E. The nonselective nitric oxide synthase (NOS) inhibitor 7-NINA concentration-dependently inhibited BK effects. BK-induced relaxation was prevented by the selective antagonists for EP3 (L 826266), but not by EP1 (SC 19221), EP1/EP2 (AH 6809) or EP4 (L161982) receptor antagonists. Otherwise, the selective inhibitors of protein kinases A, G and C, mitogen-activated protein kinases, phospholipases C and A2, nuclear factor-kappaB or potassium channels all failed to significantly interfere with BK-mediated relaxation.BK caused a marked increase in PGE2 levels, an effect that was prevented by NS 398, HOE 140 or AG 490. COX-2 expression did not differ in preparations with or without epithelium, and it was not changed by BK stimulation. However, incubation with BK significantly increased the endothelial NOS (eNOS) and neuronal NOS (nNOS) expression, independent of the epithelium integrity. Our results indicate that BK-induced relaxation in GPT + E depends on prostanoids (probably PGE2 acting via EP3 receptors) and NO release and seems to involve complex interactions between kinin B2 receptors, COX-2, nNOS, eNOS and tyrosine kinases.
Collapse
Affiliation(s)
- Valfredo Schlemper
- Department of Pharmacology, Centre of Biological Sciences, Universidade Federal de Santa Catarina – UFSC, Florianópolis, SC, Brazil
- Department of Biological and Health Sciences, Universidade do Planalto Catarinense – UNIPLAC, Lages, SC, Brazil
| | - Rodrigo Medeiros
- Department of Pharmacology, Centre of Biological Sciences, Universidade Federal de Santa Catarina – UFSC, Florianópolis, SC, Brazil
| | - Juliano Ferreira
- Department of Pharmacology, Centre of Biological Sciences, Universidade Federal de Santa Catarina – UFSC, Florianópolis, SC, Brazil
| | - Maria M Campos
- Department of Pharmacology, Centre of Biological Sciences, Universidade Federal de Santa Catarina – UFSC, Florianópolis, SC, Brazil
| | - João B Calixto
- Department of Pharmacology, Centre of Biological Sciences, Universidade Federal de Santa Catarina – UFSC, Florianópolis, SC, Brazil
- Author for correspondence:
| |
Collapse
|
49
|
Hecquet C, Biyashev D, Tan F, Erdös EG. Positive cooperativity between the thrombin and bradykinin B2 receptors enhances arachidonic acid release. Am J Physiol Heart Circ Physiol 2005; 290:H948-58. [PMID: 16183725 PMCID: PMC1656694 DOI: 10.1152/ajpheart.00868.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bradykinin (BK) or kallikreins activate B2 receptors (R) that couple Galpha(i) and Galpha(q) proteins to release arachidonic acid (AA) and elevate intracellular Ca2+ concentration ([Ca2+]i). Thrombin cleaves the protease-activated-receptor-1 (PAR1) that couples Galpha(i), Galpha(q), and Galpha(12/13) proteins. In Chinese hamster ovary cells stably transfected with human B2R, thrombin liberated little AA, but it significantly potentiated AA release by B2R agonists. We explored mechanisms of cooperativity between constitutively expressed PAR1 and B2R. We also examined human endothelial cells expressing both Rs constitutively. The PAR1 agonist hexapeptide (TRAP) was as effective as thrombin. Inhibitors of components of Galpha(i), Galpha(q), and Galpha(12/13) signaling pathways, and a protein kinase C (PKC)-alpha inhibitor, Gö-6976, blocked potentiation, while phorbol, an activator, enhanced it. Several inhibitors, including a RhoA kinase inhibitor, a [Ca2+]i antagonist, and an inositol-(1,3,4)-trisphosphate R antagonist, reduced mobilization of [Ca2+]i by thrombin and blocked potentiation of AA release by B2R agonists. Because either a nonselective inhibitor (isotetrandrine) of phospholipase A2 (PLA2) or a Ca2+-dependent PLA2 inhibitor abolished potentiation of AA release by thrombin, while a Ca2+-independent PLA2 inhibitor did not, we concluded that the mechanism involves Ca2+-dependent PLA2 activation. Both thrombin and TRAP modified activation and phosphorylation of the B2R induced by BK. In lower concentrations they enhanced it, while higher concentrations inhibited phosphorylation and diminished B2R activation. Protection of the NH2-terminal Ser1-Phe2 bond of TRAP by an aminopeptidase inhibitor made this peptide much more active than the unprotected agonist. Thus PAR1 activation enhances AA release by B2R agonists through signal transduction pathway.
Collapse
Affiliation(s)
| | | | - Fulong Tan
- Depts. of Pharmacology and
- Anesthesiology U. Illinois Coll. Med. at Chicago
| | - Ervin G. Erdös
- Depts. of Pharmacology and
- Anesthesiology U. Illinois Coll. Med. at Chicago
- Correspondence to: Ervin G. Erdös, MD, U. Illinois Coll. of Med. at Chicago, Dept of Pharmacology (M/C 868), 835 S. Wolcott Ave., Room E403, Chicago, IL 60612 USA, Telephone: (312) 996-9146, Fax: (312) 996-1648, E-MAIL:
| |
Collapse
|
50
|
Hur EM, Park YS, Huh YH, Yoo SH, Woo KC, Choi BH, Kim KT. Junctional membrane inositol 1,4,5-trisphosphate receptor complex coordinates sensitization of the silent EGF-induced Ca2+ signaling. ACTA ACUST UNITED AC 2005; 169:657-67. [PMID: 15911880 PMCID: PMC2171708 DOI: 10.1083/jcb.200411034] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca(2+) is a highly versatile intracellular signal that regulates many different cellular processes, and cells have developed mechanisms to have exquisite control over Ca(2+) signaling. Epidermal growth factor (EGF), which fails to mobilize intracellular Ca(2+) when administrated alone, becomes capable of evoking [Ca(2+)](i) increase and exocytosis after bradykinin (BK) stimulation in chromaffin cells. Here, we provide evidence that this sensitization process is coordinated by a macromolecular signaling complex comprised of inositol 1,4,5-trisphosphate receptor type I (IP(3)R1), cAMP-dependent protein kinase (PKA), EGF receptor (EGFR), and an A-kinase anchoring protein, yotiao. The IP(3)R complex functions as a focal point to promote Ca(2+) release in two ways: (1) it facilitates PKA-dependent phosphorylation of IP(3)R1 in response to BK-induced elevation of cAMP, and (2) it couples the plasmalemmal EGFR with IP(3)R1 at the Ca(2+) store located juxtaposed to the plasma membrane. Our study illustrates how the junctional membrane IP(3)R complex connects different signaling pathways to define the fidelity and specificity of Ca(2+) signaling.
Collapse
Affiliation(s)
- Eun-Mi Hur
- National Research Laboratory of Molecular Neurophysiology, Pohang University of Science and Technology, Hyo-ja dong, San31, Pohang, 790-784, South Korea
| | | | | | | | | | | | | |
Collapse
|