1
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Huang Z. Evidence that Alzheimer's Disease Is a Disease of Competitive Synaptic Plasticity Gone Awry. J Alzheimers Dis 2024; 99:447-470. [PMID: 38669548 PMCID: PMC11119021 DOI: 10.3233/jad-240042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
Mounting evidence indicates that a physiological function of amyloid-β (Aβ) is to mediate neural activity-dependent homeostatic and competitive synaptic plasticity in the brain. I have previously summarized the lines of evidence supporting this hypothesis and highlighted the similarities between Aβ and anti-microbial peptides in mediating cell/synapse competition. In cell competition, anti-microbial peptides deploy a multitude of mechanisms to ensure both self-protection and competitor elimination. Here I review recent studies showing that similar mechanisms are at play in Aβ-mediated synapse competition and perturbations in these mechanisms underpin Alzheimer's disease (AD). Specifically, I discuss evidence that Aβ and ApoE, two crucial players in AD, co-operate in the regulation of synapse competition. Glial ApoE promotes self-protection by increasing the production of trophic monomeric Aβ and inhibiting its assembly into toxic oligomers. Conversely, Aβ oligomers, once assembled, promote the elimination of competitor synapses via direct toxic activity and amplification of "eat-me" signals promoting the elimination of weak synapses. I further summarize evidence that neuronal ApoE may be part of a gene regulatory network that normally promotes competitive plasticity, explaining the selective vulnerability of ApoE expressing neurons in AD brains. Lastly, I discuss evidence that sleep may be key to Aβ-orchestrated plasticity, in which sleep is not only induced by Aβ but is also required for Aβ-mediated plasticity, underlining the link between sleep and AD. Together, these results strongly argue that AD is a disease of competitive synaptic plasticity gone awry, a novel perspective that may promote AD research.
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Affiliation(s)
- Zhen Huang
- Departments of Neuroscience and Neurology, University of Wisconsin-Madison, Madison, WI, USA
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2
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Fyn-kinase and caveolin-1 in the alveolar epithelial junctional adherence complex contribute to the early stages of pulmonary fibrosis. Eur J Pharm Sci 2022; 175:106236. [PMID: 35710078 DOI: 10.1016/j.ejps.2022.106236] [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: 01/26/2022] [Revised: 06/03/2022] [Accepted: 06/11/2022] [Indexed: 11/23/2022]
Abstract
Current pathophysiological findings indicate that damage to the alveolar epithelium plays a decisive role in the development of idiopathic pulmonary fibrosis (IPF). The available pharmacological interventions (i.e., oral pirfenidone and nintedanib) only slow down progression of the disease, but do not offer a cure. In order to develop new drug candidates, the pathophysiology of IPF needs to be better understood on a molecular level. It has previously been reported that a loss of caveolin-1 (Cav-1) contributes to profibrotic processes by causing reduced alveolar barrier function and fibrosis-like alterations of the lung-parenchyma. Conversely, overexpression of caveolin-1 appears to counteract the development of fibrosis by inhibiting the inflammasome NLRP3 and the associated expression of interleukin-1β. In this study, the interaction between Fyn-kinase and caveolin-1 in the alveolar epithelium of various bleomycin (BLM)/TGF-β damage models using precision-cut lung slices (PCLS), wildtype (WT) and caveolin-1 knockout (KO) mice as well as the human NCI-H441 cell line, were investigated. In WT mouse lung tissues, strong signals for Fyn-kinase were detected in alveolar epithelial type I cells, whereas in caveolin-1 KO animals, expression shifted to alveolar epithelial type II cells. Caveolin-1 and Fyn-kinase were found to be co-localized in isolated lipid rafts of NCI-H441 cell membrane fractions. These findings were corroborated by co-immunoprecipitation studies in which a co-localization of Cav-1 and Fyn-kinase was detected in the cell membrane of the alveolar epithelium. After TGF-β and BLM-induced damage to the alveolar epithelium both in PCLS and cell culture experiments, a decrease in caveolin-1 and Fyn-kinase was found. Furthermore, TEER (transepithelial electrical resistance) measurements indicated that TGF-β and BLM have a damaging effect on cell-cell contacts and thus impair the barrier function in NCI-H441 cell monolayers. This effect was attenuated after co-incubation with the Fyn-kinase inhibitor, PP-2. Our data suggest an involvement of Fyn-kinase and caveolin-1 in TGF-β/bleomycin-induced impairment of alveolar barrier function and thus a possible role in the early stages of pulmonary fibrosis. Fyn-kinase and/or its complex with caveolin-1 might, therefore, be novel therapeutic targets in IPF.
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3
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Dudãu M, Codrici E, Tanase C, Gherghiceanu M, Enciu AM, Hinescu ME. Caveolae as Potential Hijackable Gates in Cell Communication. Front Cell Dev Biol 2020; 8:581732. [PMID: 33195223 PMCID: PMC7652756 DOI: 10.3389/fcell.2020.581732] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/08/2020] [Indexed: 12/16/2022] Open
Abstract
Caveolae are membrane microdomains described in many cell types involved in endocytocis, transcytosis, cell signaling, mechanotransduction, and aging. They are found at the interface with the extracellular environment and are structured by caveolin and cavin proteins. Caveolae and caveolins mediate transduction of chemical messages via signaling pathways, as well as non-chemical messages, such as stretching or shear stress. Various pathogens or signals can hijack these gates, leading to infectious, oncogenic and even caveolin-related diseases named caveolinopathies. By contrast, preclinical and clinical research have fallen behind in their attempts to hijack caveolae and caveolins for therapeutic purposes. Caveolae involvement in human disease is not yet fully explored or understood and, of all their scaffold proteins, only caveolin-1 is being considered in clinical trials as a possible biomarker of disease. This review briefly summarizes current knowledge about caveolae cell signaling and raises the hypothesis whether these microdomains could serve as hijackable “gatekeepers” or “gateways” in cell communication. Furthermore, because cell signaling is one of the most dynamic domains in translating data from basic to clinical research, we pay special attention to translation of caveolae, caveolin, and cavin research into clinical practice.
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Affiliation(s)
- Maria Dudãu
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Cell Biology and Histology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Elena Codrici
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania
| | - Cristiana Tanase
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Clinical Biochemistry Department, Faculty of Medicine, Titu Maiorescu University, Bucharest, Romania
| | - Mihaela Gherghiceanu
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Cell Biology and Histology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Ana-Maria Enciu
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Cell Biology and Histology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Mihail E Hinescu
- Biochemistry-Proteomics Laboratory, Victor Babes National Institute of Pathology, Bucharest, Romania.,Cell Biology and Histology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
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4
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A New Take on Prion Protein Dynamics in Cellular Trafficking. Int J Mol Sci 2020; 21:ijms21207763. [PMID: 33092231 PMCID: PMC7589859 DOI: 10.3390/ijms21207763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022] Open
Abstract
The mobility of cellular prion protein (PrPC) in specific cell membrane domains and among distinct cell compartments dictates its molecular interactions and directs its cell function. PrPC works in concert with several partners to organize signaling platforms implicated in various cellular processes. The scaffold property of PrPC is able to gather a molecular repertoire to create heterogeneous membrane domains that favor endocytic events. Dynamic trafficking of PrPC through multiple pathways, in a well-orchestrated mechanism of intra and extracellular vesicular transport, defines its functional plasticity, and also assists the conversion and spreading of its infectious isoform associated with neurodegenerative diseases. In this review, we highlight how PrPC traffics across intra- and extracellular compartments and the consequences of this dynamic transport in governing cell functions and contributing to prion disease pathogenesis.
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5
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Cellular Prion Protein (PrPc): Putative Interacting Partners and Consequences of the Interaction. Int J Mol Sci 2020; 21:ijms21197058. [PMID: 32992764 PMCID: PMC7583789 DOI: 10.3390/ijms21197058] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/20/2020] [Accepted: 09/23/2020] [Indexed: 02/08/2023] Open
Abstract
Cellular prion protein (PrPc) is a small glycosylphosphatidylinositol (GPI) anchored protein most abundantly found in the outer leaflet of the plasma membrane (PM) in the central nervous system (CNS). PrPc misfolding causes neurodegenerative prion diseases in the CNS. PrPc interacts with a wide range of protein partners because of the intrinsically disordered nature of the protein’s N-terminus. Numerous studies have attempted to decipher the physiological role of the prion protein by searching for proteins which interact with PrPc. Biochemical characteristics and biological functions both appear to be affected by interacting protein partners. The key challenge in identifying a potential interacting partner is to demonstrate that binding to a specific ligand is necessary for cellular physiological function or malfunction. In this review, we have summarized the intracellular and extracellular interacting partners of PrPc and potential consequences of their binding. We also briefly describe prion disease-related mutations at the end of this review.
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6
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Chida J, Hara H, Uchiyama K, Takahashi E, Miyata H, Kosako H, Tomioka Y, Ito T, Horiuchi H, Matsuda H, Kido H, Sakaguchi S. Prion protein signaling induces M2 macrophage polarization and protects from lethal influenza infection in mice. PLoS Pathog 2020; 16:e1008823. [PMID: 32845931 PMCID: PMC7489546 DOI: 10.1371/journal.ppat.1008823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 09/14/2020] [Accepted: 07/20/2020] [Indexed: 11/18/2022] Open
Abstract
The cellular prion protein, PrPC, is a glycosylphosphatidylinositol anchored-membrane glycoprotein expressed most abundantly in neuronal and to a lesser extent in non-neuronal cells. Its conformational conversion into the amyloidogenic isoform in neurons is a key pathogenic event in prion diseases, including Creutzfeldt-Jakob disease in humans and scrapie and bovine spongiform encephalopathy in animals. However, the normal functions of PrPC remain largely unknown, particularly in non-neuronal cells. Here we show that stimulation of PrPC with anti-PrP monoclonal antibodies (mAbs) protected mice from lethal infection with influenza A viruses (IAVs), with abundant accumulation of anti-inflammatory M2 macrophages with activated Src family kinases (SFKs) in infected lungs. A SFK inhibitor dasatinib inhibited M2 macrophage accumulation in IAV-infected lungs after treatment with anti-PrP mAbs and abolished the anti-PrP mAb-induced protective activity against lethal influenza infection in mice. We also show that stimulation of PrPC with anti-PrP mAbs induced M2 polarization in peritoneal macrophages through SFK activation in vitro and in vivo. These results indicate that PrPC could activate SFK in macrophages and induce macrophage polarization to an anti-inflammatory M2 phenotype after stimulation with anti-PrP mAbs, thereby eliciting protective activity against lethal infection with IAVs in mice after treatment with anti-PrP mAbs. These results also highlight PrPC as a novel therapeutic target for IAV infection.
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Affiliation(s)
- Junji Chida
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Hideyuki Hara
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Keiji Uchiyama
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Etsuhisa Takahashi
- Division of Enzyme Chemistry, The Institute for Enzyme Research, Tokushima University (KOSOKEN), Tokushima, Japan
| | - Hironori Miyata
- Animal Research Center, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Hidetaka Kosako
- Division of Cell Signaling, Fujii Memorial Institute of Medical Sciences, Tokushima University, Kuramoto-cho, Tokushima, Japan
| | - Yukiko Tomioka
- Laboratory of Laboratory Animal Science, Joint Department of Veterinary Medicine, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Toshihiro Ito
- Avian Zoonosis Research Center, Faculty of Agriculture, Tottori University, Koyama-cho, Tottori, Japan
| | - Hiroyuki Horiuchi
- Laboratory of Immunobiology, Graduate School of Integrated Sciences for Life, Hiroshima University, Japan
| | - Haruo Matsuda
- Laboratory of Immunobiology, Department of Molecular and Applied Bioscience, Graduate School of Biosphere Science, Hiroshima University, Japan
| | - Hiroshi Kido
- Division of Enzyme Chemistry, The Institute for Enzyme Research, Tokushima University (KOSOKEN), Tokushima, Japan
| | - Suehiro Sakaguchi
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
- * E-mail:
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Choi S, Kim JA, Li HY, Lee SJ, Seok YS, Kim TH, Han KH, Park MH, Cho GJ, Suh SH. Altered Redox State Modulates Endothelial K Ca2.3 and K Ca3.1 Levels in Normal Pregnancy and Preeclampsia. Antioxid Redox Signal 2019; 30:505-519. [PMID: 29334762 DOI: 10.1089/ars.2017.7038] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS Altered redox state has been related to the development of normal pregnancy (NP) and preeclampsia (PE). Endothelial KCa2.3 and KCa3.1 (KCas) play an important role in vasodilation, and KCas levels are affected by oxidative stress. We investigated the mechanisms of oxidative stress-mediated KCas expression modulation during NP and PE. RESULTS Human uterine microvascular endothelial cells were incubated in serum from normal nonpregnant women (n = 13) and women with NP (n = 24) or PE (n = 15), or in vascular endothelial growth factor (VEGF), oxidized low-density lipoprotein (ox-LDL), progesterone, or estradiol-17β (E2)-containing medium for 24 h. NP serum elevated H2O2 levels via reducing catalase and glutathione peroxidase 1 levels, thereby enhancing KCas levels via a H2O2/fyn/extracellular signal-regulated kinase (ERK)-mediated pathway. VEGF enhanced H2O2 and KCas levels and KCa3.1 currents. KCas were upregulated and KCas activation-induced endothelium-dependent relaxation (EDR) was augmented in vessels from pregnant mice and rats. Whereas PE serum, ox-LDL, progesterone, or soluble fms-like tyrosine kinase 1 (sFlt-1) elevated superoxide levels via elevating NADPH oxidase 2 (NOX2) and NOX4 levels and reducing superoxide dismutase (SOD) 1 levels, thereby downregulating KCas. sFlt-1 inhibited EDR. PE serum- or progesterone-induced alterations in levels of KCas were reversed by polyethylene glycol-SOD, NOX inhibition, or E2. Innovation and Conclusions: This is the first study of how endothelial KCas levels are modulated during NP and PE. KCas were upregulated by soluble serum factors such as VEGF via H2O2 generation in NP, and were downregulated by serum factors such as progesterone and ox-LDL via superoxide generation in PE, which may contribute to hemodynamic adaptations in NP or to the development of PE.
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Affiliation(s)
- Shinkyu Choi
- 1 Department of Physiology, Medical School, Ewha Womans University , Seoul, Republic of Korea
| | - Ji Aee Kim
- 1 Department of Physiology, Medical School, Ewha Womans University , Seoul, Republic of Korea
| | - Hai-Yan Li
- 1 Department of Physiology, Medical School, Ewha Womans University , Seoul, Republic of Korea
| | - Sae-Jin Lee
- 2 Department of Anatomy, Medical School, Ewha Womans University , Seoul, Republic of Korea
| | - Ye Seon Seok
- 3 Department of Obstetrics and Gynecology, Medical School, Korea University , Seoul, Republic of Korea
| | - Tae Hun Kim
- 4 Department of Internal Medicine, and Medical School, Ewha Womans University , Seoul, Republic of Korea
| | - Ki-Hwan Han
- 2 Department of Anatomy, Medical School, Ewha Womans University , Seoul, Republic of Korea
| | - Mi Hye Park
- 5 Department of Obstetrics and Gynecology, Medical School, Ewha Womans University , Seoul, Republic of Korea
| | - Geum Joon Cho
- 3 Department of Obstetrics and Gynecology, Medical School, Korea University , Seoul, Republic of Korea
| | - Suk Hyo Suh
- 1 Department of Physiology, Medical School, Ewha Womans University , Seoul, Republic of Korea
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8
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Martellucci S, Santacroce C, Santilli F, Piccoli L, Delle Monache S, Angelucci A, Misasi R, Sorice M, Mattei V. Cellular and Molecular Mechanisms Mediated by recPrP C Involved in the Neuronal Differentiation Process of Mesenchymal Stem Cells. Int J Mol Sci 2019; 20:E345. [PMID: 30654447 PMCID: PMC6358746 DOI: 10.3390/ijms20020345] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 12/21/2022] Open
Abstract
Human Dental Pulp Stem Cells (hDPSCs) represent a type of adult mesenchymal stem cells that have the ability to differentiate in vitro in several lineages such as odontoblasts, osteoblasts, chondrocytes, adipocytes and neurons. In the current work, we used hDPSCs as the experimental model to study the role of recombinant prion protein 23⁻231 (recPrPC) in the neuronal differentiation process, and in the signal pathway activation of ERK 1/2 and Akt. We demonstrated that recPrPC was able to activate an intracellular signal pathway mediated by extracellular-signal-regulated kinase 1 and 2 (ERK 1/2) and protein kinase B (Akt). Moreover, in order to understand whether endogenous prion protein (PrPC) was necessary to mediate the signaling induced by recPrPC, we silenced PrPC, demonstrating that the presence of endogenous PrPC was essential for ERK 1/2 and Akt phosphorylation. Since endogenous PrPC is a well-known lipid rafts component, we evaluated the role of these structures in the signal pathway induced by recPrPC. Our results suggest that lipid rafts integrity play a key role in recPrPC activity. In fact, lipid rafts inhibitors, such as fumonisin B1 and MβCD, significantly prevented ERK 1/2 and Akt phosphorylation induced by recPrPC. In addition, we investigated the capacity of recPrPC to induce hDPSCs neuronal differentiation process after long-term stimulation through the evaluation of typical neuronal markers expression such as B3-Tubulin, neurofilament-H (NFH) and growth associated protein 43 (GAP43). Accordingly, when we silenced endogenous PrPC, we observed the inhibition of neuronal differentiation induced by recPrPC. The combined data suggest that recPrPC plays a key role in the neuronal differentiation process and in the activation of specific intracellular signal pathways in hDPSCs.
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Affiliation(s)
- Stefano Martellucci
- Laboratory of Experimental Medicine and Environmental Pathology, Rieti University Hub "Sabina Universitas", 02100 Rieti, Italy.
- Department of Experimental Medicine, "Sapienza" University, 00161 Rome, Italy.
| | - Costantino Santacroce
- Laboratory of Experimental Medicine and Environmental Pathology, Rieti University Hub "Sabina Universitas", 02100 Rieti, Italy.
| | - Francesca Santilli
- Laboratory of Experimental Medicine and Environmental Pathology, Rieti University Hub "Sabina Universitas", 02100 Rieti, Italy.
- Department of Experimental Medicine, "Sapienza" University, 00161 Rome, Italy.
| | - Luca Piccoli
- Department of Science Dentistry and Maxillofacial, "Sapienza" University, 00161 Rome, Italy.
| | - Simona Delle Monache
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100 L'Aquila, Italy.
| | - Adriano Angelucci
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100 L'Aquila, Italy.
| | - Roberta Misasi
- Department of Experimental Medicine, "Sapienza" University, 00161 Rome, Italy.
| | - Maurizio Sorice
- Department of Experimental Medicine, "Sapienza" University, 00161 Rome, Italy.
| | - Vincenzo Mattei
- Laboratory of Experimental Medicine and Environmental Pathology, Rieti University Hub "Sabina Universitas", 02100 Rieti, Italy.
- Department of Experimental Medicine, "Sapienza" University, 00161 Rome, Italy.
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9
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Martellucci S, Manganelli V, Santacroce C, Santilli F, Piccoli L, Sorice M, Mattei V. Role of Prion protein-EGFR multimolecular complex during neuronal differentiation of human dental pulp-derived stem cells. Prion 2018; 12:117-126. [PMID: 29644924 DOI: 10.1080/19336896.2018.1463797] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cellular prion protein (PrPC) is expressed in a wide variety of stem cells in which regulates their self-renewal as well as differentiation potential. In this study we investigated the presence of PrPC in human dental pulp-derived stem cells (hDPSCs) and its role in neuronal differentiation process. We show that hDPSCs expresses early PrPC at low concentration and its expression increases after two weeks of treatment with EGF/bFGF. Then, we analyzed the association of PrPC with gangliosides and EGF receptor (EGF-R) during neuronal differentiation process. PrPC associates constitutively with GM2 in control hDPSCs and with GD3 only after neuronal differentiation. Otherwise, EGF-R associates weakly in control hDPSCs and more markedly after neuronal differentiation. To analyze the functional role of PrPC in the signal pathway mediated by EGF/EGF-R, a siRNA PrP was applied to ablate PrPC and its function. The treatment with siRNA PrP significantly prevented Akt and ERK1/2 phosphorylation induced by EGF. Moreover, siRNA PrP treatment significantly prevented neuronal-specific antigens expression induced by EGF/bFGF, indicating that cellular prion protein is essential for EGF/bFGF-induced hDPSCs differentiation. These results suggest that PrPC interact with EGF-R within lipid rafts, playing a role in the multimolecular signaling complexes involved in hDPSCs neuronal differentiation.
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Affiliation(s)
- Stefano Martellucci
- a Laboratory of Experimental Medicine and Environmental Pathology - Rieti University Hub "Sabina Universitas" , Via Angelo Maria Ricci 35/A, Rieti , Italy.,b Department of Experimental Medicine - "Sapienza" University , Viale Regina Elena 324, Rome , Italy
| | - Valeria Manganelli
- b Department of Experimental Medicine - "Sapienza" University , Viale Regina Elena 324, Rome , Italy
| | - Costantino Santacroce
- a Laboratory of Experimental Medicine and Environmental Pathology - Rieti University Hub "Sabina Universitas" , Via Angelo Maria Ricci 35/A, Rieti , Italy
| | - Francesca Santilli
- a Laboratory of Experimental Medicine and Environmental Pathology - Rieti University Hub "Sabina Universitas" , Via Angelo Maria Ricci 35/A, Rieti , Italy
| | - Luca Piccoli
- c Department of Science Dentistry and Maxillofacial - "Sapienza" University , Viale Regina Elena 287/A, Rome , Italy
| | - Maurizio Sorice
- b Department of Experimental Medicine - "Sapienza" University , Viale Regina Elena 324, Rome , Italy
| | - Vincenzo Mattei
- a Laboratory of Experimental Medicine and Environmental Pathology - Rieti University Hub "Sabina Universitas" , Via Angelo Maria Ricci 35/A, Rieti , Italy.,b Department of Experimental Medicine - "Sapienza" University , Viale Regina Elena 324, Rome , Italy
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10
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Characterization of physiochemical properties of caveolin-1 from normal and prion-infected human brains. Oncotarget 2017; 8:53888-53898. [PMID: 28903310 PMCID: PMC5589549 DOI: 10.18632/oncotarget.19431] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 07/12/2017] [Indexed: 01/04/2023] Open
Abstract
Caveolin-1 is a major component protein of the caveolae—a type of flask shaped, 50-100 nm, nonclathrin-coated, microdomain present in the plasma membrane of most mammalian cells. Caveolin-1 functions as a scaffolding protein to organize and concentrate signaling molecules within the caveolae, which may be associated with its unique physicochemical properties including oligomerization, acquisition of detergent insolubility, and association with cholesterol. Here we demonstrate that caveolin-1 is detected in all brain areas examined and recovered in both detergent-soluble and -insoluble fractions. Surprisingly, the recovered molecules from the two different fractions share a similar molecular size ranging from 200 to 2,000 kDa, indicated by gel filtration. Furthermore, both soluble and insoluble caveolin-1 molecules generate a proteinase K (PK)-resistant C-terminal core fragment upon the PK-treatment, by removing ˜36 amino acids from the N-terminus of the protein. Although it recognizes caveolin-1 from A431 cell lysate, an antibody against the C-terminus of caveolin-1 fails to detect the brain protein by Western blotting, suggesting that the epitope in the brain caveolin-1 is concealed. No significant differences in the physicochemical properties of caveolin-1 between uninfected and prion-infected brains are observed.
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11
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Toni M, Massimino ML, De Mario A, Angiulli E, Spisni E. Metal Dyshomeostasis and Their Pathological Role in Prion and Prion-Like Diseases: The Basis for a Nutritional Approach. Front Neurosci 2017; 11:3. [PMID: 28154522 PMCID: PMC5243831 DOI: 10.3389/fnins.2017.00003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 01/03/2017] [Indexed: 12/11/2022] Open
Abstract
Metal ions are key elements in organisms' life acting like cofactors of many enzymes but they can also be potentially dangerous for the cell participating in redox reactions that lead to the formation of reactive oxygen species (ROS). Any factor inducing or limiting a metal dyshomeostasis, ROS production and cell injury may contribute to the onset of neurodegenerative diseases or play a neuroprotective action. Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of fatal neurodegenerative disorders affecting the central nervous system (CNS) of human and other mammalian species. The causative agent of TSEs is believed to be the scrapie prion protein PrPSc, the β sheet-rich pathogenic isoform produced by the conformational conversion of the α-helix-rich physiological isoform PrPC. The peculiarity of PrPSc is its ability to self-propagate in exponential fashion in cells and its tendency to precipitate in insoluble and protease-resistance amyloid aggregates leading to neuronal cell death. The expression “prion-like diseases” refers to a group of neurodegenerative diseases that share some neuropathological features with prion diseases such as the involvement of proteins (α-synuclein, amyloid β, and tau) able to precipitate producing amyloid deposits following conformational change. High social impact diseases such as Alzheimer's and Parkinson's belong to prion-like diseases. Accumulating evidence suggests that the exposure to environmental metals is a risk factor for the development of prion and prion-like diseases and that metal ions can directly bind to prion and prion-like proteins affecting the amount of amyloid aggregates. The diet, source of metal ions but also of natural antioxidant and chelating agents such as polyphenols, is an aspect to take into account in addressing the issue of neurodegeneration. Epidemiological data suggest that the Mediterranean diet, based on the abundant consumption of fresh vegetables and on low intake of meat, could play a preventive or delaying role in prion and prion-like neurodegenerative diseases. In this review, metal role in the onset of prion and prion-like diseases is dealt with from a nutritional, cellular, and molecular point of view.
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Affiliation(s)
- Mattia Toni
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University Rome, Italy
| | - Maria L Massimino
- National Research Council (CNR), Neuroscience Institute c/o Department of Biomedical Sciences, University of Padova Padova, Italy
| | - Agnese De Mario
- Department of Biomedical Sciences, University of Padova Padova, Italy
| | - Elisa Angiulli
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University Rome, Italy
| | - Enzo Spisni
- Department of Biological, Geological and Environmental Sciences, University of Bologna Bologna, Italy
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Choi S, Kim JA, Li H, Shin K, Oh GT, Lee Y, Oh S, Pewzner‐Jung Y, Futerman AH, Suh SH. KCa 3.1 upregulation preserves endothelium-dependent vasorelaxation during aging and oxidative stress. Aging Cell 2016; 15:801-10. [PMID: 27363720 PMCID: PMC5013018 DOI: 10.1111/acel.12502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2016] [Indexed: 01/24/2023] Open
Abstract
Endothelial oxidative stress develops with aging and reactive oxygen species impair endothelium-dependent relaxation (EDR) by decreasing nitric oxide (NO) availability. Endothelial KCa 3.1, which contributes to EDR, is upregulated by H2 O2 . We investigated whether KCa 3.1 upregulation compensates for diminished EDR to NO during aging-related oxidative stress. Previous studies identified that the levels of ceramide synthase 5 (CerS5), sphingosine, and sphingosine 1-phosphate were increased in aged wild-type and CerS2 mice. In primary mouse aortic endothelial cells (MAECs) from aged wild-type and CerS2 null mice, superoxide dismutase (SOD) was upregulated, and catalase and glutathione peroxidase 1 (GPX1) were downregulated, when compared to MAECs from young and age-matched wild-type mice. Increased H2 O2 levels induced Fyn and extracellular signal-regulated kinases (ERKs) phosphorylation and KCa 3.1 upregulation. Catalase/GPX1 double knockout (catalase(-/-) /GPX1(-/-) ) upregulated KCa 3.1 in MAECs. NO production was decreased in aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) MAECs. However, KCa 3.1 activation-induced, N(G) -nitro-l-arginine-, and indomethacin-resistant EDR was increased without a change in acetylcholine-induced EDR in aortic rings from aged wild-type, CerS2 null, and catalase(-/-) /GPX1(-/-) mice. CerS5 transfection or exogenous application of sphingosine or sphingosine 1-phosphate induced similar changes in levels of the antioxidant enzymes and upregulated KCa 3.1. Our findings suggest that, during aging-related oxidative stress, SOD upregulation and downregulation of catalase and GPX1, which occur upon altering the sphingolipid composition or acyl chain length, generate H2 O2 and thereby upregulate KCa 3.1 expression and function via a H2 O2 /Fyn-mediated pathway. Altogether, enhanced KCa 3.1 activity may compensate for decreased NO signaling during vascular aging.
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Affiliation(s)
- Shinkyu Choi
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Ji Aee Kim
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Hai‐yan Li
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
| | - Kyong‐Oh Shin
- College of Pharmacy and MRC Chungbuk National University Chongju South Korea
| | - Goo Taeg Oh
- Department of Life Sciences Ewha Womans University Seoul South Korea
| | - Yong‐Moon Lee
- College of Pharmacy and MRC Chungbuk National University Chongju South Korea
| | - Seikwan Oh
- Department of Molecular Medicine Medical School Ewha Womans University Seoul South Korea
| | - Yael Pewzner‐Jung
- Department of Biological Chemistry Weizmann Institute of Science Rehovot Israel
| | - Anthony H. Futerman
- Department of Biological Chemistry Weizmann Institute of Science Rehovot Israel
| | - Suk Hyo Suh
- Department of Physiology Medical School Ewha Womans University Seoul South Korea
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13
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Dias MVS, Teixeira BL, Rodrigues BR, Sinigaglia-Coimbra R, Porto-Carreiro I, Roffé M, Hajj GNM, Martins VR. PRNP/prion protein regulates the secretion of exosomes modulating CAV1/caveolin-1-suppressed autophagy. Autophagy 2016; 12:2113-2128. [PMID: 27629560 DOI: 10.1080/15548627.2016.1226735] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Prion protein modulates many cellular functions including the secretion of trophic factors by astrocytes. Some of these factors are found in exosomes, which are formed within multivesicular bodies (MVBs) and secreted into the extracellular space to modulate cell-cell communication. The mechanisms underlying exosome biogenesis were not completely deciphered. Here, we demonstrate that primary cultures of astrocytes and fibroblasts from prnp-null mice secreted lower levels of exosomes than wild-type cells. Furthermore, prnp-null astrocytes exhibited reduced MVB formation and increased autophagosome formation. The reconstitution of PRNP expression at the cell membrane restored exosome secretion in PRNP-deficient astrocytes, whereas macroautophagy/autophagy inhibition via BECN1 depletion reestablished exosome release in these cells. Moreover, the PRNP octapeptide repeat domain was necessary to promote exosome secretion and to impair the formation of the CAV1-dependent ATG12-ATG5 cytoplasmic complex that drives autophagosome formation. Accordingly, higher levels of CAV1 were found in lipid raft domains instead of in the cytoplasm in prnp-null cells. Collectively, these findings demonstrate that PRNP supports CAV1-suppressed autophagy to protect MVBs from sequestration into phagophores, thus facilitating exosome secretion.
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Affiliation(s)
- Marcos V S Dias
- a International Research Center , A.C. Camargo Cancer Center , São Paulo , Brazil , National Institute for Oncogenomics, INCITO
| | - Bianca L Teixeira
- a International Research Center , A.C. Camargo Cancer Center , São Paulo , Brazil , National Institute for Oncogenomics, INCITO
| | - Bruna R Rodrigues
- a International Research Center , A.C. Camargo Cancer Center , São Paulo , Brazil , National Institute for Oncogenomics, INCITO
| | | | | | - Martín Roffé
- a International Research Center , A.C. Camargo Cancer Center , São Paulo , Brazil , National Institute for Oncogenomics, INCITO
| | - Glaucia N M Hajj
- a International Research Center , A.C. Camargo Cancer Center , São Paulo , Brazil , National Institute for Oncogenomics, INCITO
| | - Vilma R Martins
- a International Research Center , A.C. Camargo Cancer Center , São Paulo , Brazil , National Institute for Oncogenomics, INCITO
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Xu L, Guo R, Xie Y, Ma M, Ye R, Liu X. Caveolae: molecular insights and therapeutic targets for stroke. Expert Opin Ther Targets 2015; 19:633-50. [PMID: 25639269 DOI: 10.1517/14728222.2015.1009446] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Caveolae are specialized plasma membrane micro-invaginations of most mammalian cell types. The organization and function of caveolae are carried out by their coat proteins, caveolins and adaptor proteins, cavins. Caveolae/caveolins physically interact with membrane-associated signaling molecules and function in cholesterol incorporation, signaling transduction and macromolecular transport/permeability. AREAS COVERED Recent investigations have implicated a check-and-balance role of caveolae in the pathophysiology of cerebral ischemia. Caveolin knockout mice displayed exacerbated ischemic injury, whereas caveolin peptide exerted remarkable protection against ischemia/reperfusion injury. This review attempts to provide a comprehensive synopsis of how caveolae/caveolins modulate blood-brain barrier permeability, pro-survival signaling, angiogenesis and neuroinflammation, and how this may contribute to a better understanding of the participation of caveolae in ischemic cascade. The role of caveolin in the preconditioning-induced tolerance against ischemia is also discussed. EXPERT OPINION Caveolae represent a novel target for cerebral ischemia. It remains open how to manipulate caveolin expression in a practical way to recapitulate the beneficial therapeutic outcomes. Caveolin peptides and associated antagomirs may be efficacious and deserve further investigations for their potential benefits for stroke.
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Affiliation(s)
- Lili Xu
- Department of Neurology, Jinling Hospital, Medical School of Nanjing University , Nanjing 210002 , China
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15
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Sakudo A, Onodera T. Prion protein (PrP) gene-knockout cell lines: insight into functions of the PrP. Front Cell Dev Biol 2015; 2:75. [PMID: 25642423 PMCID: PMC4295555 DOI: 10.3389/fcell.2014.00075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/22/2014] [Indexed: 11/13/2022] Open
Abstract
Elucidation of prion protein (PrP) functions is crucial to fully understand prion diseases. A major approach to studying PrP functions is the use of PrP gene-knockout (Prnp (-/-)) mice. So far, six types of Prnp (-/-) mice have been generated, demonstrating the promiscuous functions of PrP. Recently, other PrP family members, such as Doppel and Shadoo, have been found. However, information obtained from comparative studies of structural and functional analyses of these PrP family proteins do not fully reveal PrP functions. Recently, varieties of Prnp (-/-) cell lines established from Prnp (-/-) mice have contributed to the analysis of PrP functions. In this mini-review, we focus on Prnp (-/-) cell lines and summarize currently available Prnp (-/-) cell lines and their characterizations. In addition, we introduce the recent advances in the methodology of cell line generation with knockout or knockdown of the PrP gene. We also discuss how these cell lines have provided valuable insights into PrP functions and show future perspectives.
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Affiliation(s)
- Akikazu Sakudo
- Laboratory of Biometabolic Chemistry, Faculty of Medicine, School of Health Sciences, University of the Ryukyus Nishihara, Japan
| | - Takashi Onodera
- Research Center for Food Safety, School of Agricultural and Life Sciences, University of Tokyo Tokyo, Japan
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16
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Liebert A, Bicknell B, Adams R. Prion Protein Signaling in the Nervous System—A Review and Perspective. ACTA ACUST UNITED AC 2014. [DOI: 10.4137/sti.s12319] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Prion protein (PrPC) was originally known as the causative agent of transmissible spongiform encephalopathy (TSE) but with recent research, its true function in cells is becoming clearer. It is known to act as a scaffolding protein, binding multiple ligands at the cell membrane and to be involved in signal transduction, passing information from the extracellular matrix (ECM) to the cytoplasm. Its role in the coordination of transmitters at the synapse, glyapse, and gap junction and in short- and long-range neurotrophic signaling gives PrPC a major part in neural transmission and nervous system signaling. It acts to regulate cellular function in multiple targets through its role as a controller of redox status and calcium ion flux. Given the importance of PrPC in cell physiology, this review considers its potential role in disease apart from TSE. The putative functions of PrPC point to involvement in neurodegenerative disease, neuropathic pain, chronic headache, and inflammatory disease including neuroinflammatory disease of the nervous system. Potential targets for the treatment of disease influenced by PrPC are discussed.
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Affiliation(s)
- Ann Liebert
- Faculty of Health Science, University of Sydney, Australia
| | - Brian Bicknell
- Faculty of Health Science, Australian Catholic University, Australia
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17
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Mehrabian M, Ehsani S, Schmitt-Ulms G. An emerging role of the cellular prion protein as a modulator of a morphogenetic program underlying epithelial-to-mesenchymal transition. Front Cell Dev Biol 2014; 2:53. [PMID: 25453033 PMCID: PMC4233941 DOI: 10.3389/fcell.2014.00053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/03/2014] [Indexed: 12/31/2022] Open
Abstract
Knowledge of phenotypic changes the cellular prion protein (PrP(C)) contributes to may provide novel avenues for understanding its function. Here we consider data from functional knockout/down studies and protein-protein interaction analyses from the perspective of PrP's relationship to its ancestral ZIP metal ion transporting proteins. When approached in this manner, a role of PrP(C) as a modulator of a complex morphogenetic program that underlies epithelial-to-mesenchymal transition (EMT) emerges. To execute EMT, cells have to master the challenge to shift from cell-cell to cell-substrate modes of adherence. During this process, cell-cell junctions stabilized by E-cadherins are replaced by focal adhesions that mediate cell-substrate contacts. A similar reprogramming occurs during distinct organogenesis events that have been shown to rely on ZIP transporters. A model is presented that sees ZIP transporters, and possibly also PrP(C), affect this balance of adherence modes at both the transcriptional and post-translational levels.
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Affiliation(s)
- Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto Toronto, ON, Canada ; Department of Laboratory Medicine and Pathobiology, University of Toronto Toronto, ON, Canada
| | - Sepehr Ehsani
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto Toronto, ON, Canada ; Department of Laboratory Medicine and Pathobiology, University of Toronto Toronto, ON, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto Toronto, ON, Canada ; Department of Laboratory Medicine and Pathobiology, University of Toronto Toronto, ON, Canada
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18
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Nagasawa S, Ogura K, Tsutsuki H, Saitoh H, Moss J, Iwase H, Noda M, Yahiro K. Uptake of Shiga-toxigenic Escherichia coli SubAB by HeLa cells requires an actin- and lipid raft-dependent pathway. Cell Microbiol 2014; 16:1582-601. [PMID: 24844382 DOI: 10.1111/cmi.12315] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 02/06/2023]
Abstract
The novel cytotoxic factor subtilase cytotoxin (SubAB) is produced mainly by non-O157 Shiga-toxigenic Escherichia coli (STEC). SubAB cleaves the molecular chaperone BiP/GRP78 in the endoplasmic reticulum (ER), leading to activation of RNA-dependent protein kinase (PKR)-like ER kinase (PERK), followed by caspase-dependent cell death. However, the SubAB uptake mechanism in HeLa cells is unknown. In this study, a variety of inhibitors and siRNAs were employed to characterize the SubAB uptake process. SubAB-induced BiP cleavage was inhibited by high concentrations of Dynasore, and methyl-β-cyclodextrin (mβCD) and Filipin III, but not suppressed in clathrin-, dynamin I/II-, caveolin1- and caveolin2-knockdown cells. We observed that SubAB treatment led to dramatic actin rearrangements, e.g. formation of plasma membrane blebs, with a significant increase in fluid uptake. Confocal microscopy analysis showed that SubAB uptake required actin cytoskeleton remodelling and lipid raft cholesterol. Furthermore, internalized SubAB in cells was found in the detergent-resistant domain (DRM) structure. Interestingly, IPA-3, an inhibitor of serine/threonine kinase p21-activated kinase (PAK1), an important protein of macropinocytosis, directly inhibited SubAB-mediated BiP cleavage and SubAB internalization. Thus, our findings suggest that SubAB uses lipid raft- and actin-dependent, but not clathrin-, caveolin- and dynamin-dependent pathways as its major endocytic translocation route.
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Affiliation(s)
- Sayaka Nagasawa
- Department of Legal Medicine, Graduate School of Medicine, Chiba University, Chiba, 260-8670, Japan
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19
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Wang H, Ren CH, Gunawardana CG, Schmitt-Ulms G. Overcoming barriers and thresholds - signaling of oligomeric Aβ through the prion protein to Fyn. Mol Neurodegener 2013; 8:24. [PMID: 23856335 PMCID: PMC3722066 DOI: 10.1186/1750-1326-8-24] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/09/2013] [Indexed: 12/20/2022] Open
Abstract
Evidence has been mounting for an involvement of the prion protein (PrP) in a molecular pathway assumed to play a critical role in the etiology of Alzheimer disease. A currently popular model sees oligomeric amyloid β (oAβ) peptides bind directly to PrP to emanate a signal that causes activation of the cytoplasmic tyrosine kinase Fyn, an essential player in a cascade of events that ultimately leads to NMDA receptor-mediated excitotoxicity and hyper-phosphorylation of tau. The model does not reveal, however, how extracellular binding of oAβ to PrP is communicated across the plasma membrane barrier to affect activation of Fyn. A scenario whereby PrP may adapt a transmembrane topology to affect Fyn activation in the absence of additional partners is currently not supported by evidence. A survey of known candidate PrP interactors leads to a small number of molecules that are known to acquire a transmembrane topology and understood to contribute to Fyn activation. Because multiple signaling pathways converge onto Fyn, a realistic model needs to take into account a reality of Fyn acting as a hub that integrates signals from multiple inhibitory and activating effectors. To clarify the role of PrP in oAβ-dependent excitotoxicity, future studies may need to incorporate experimental designs that can probe the contributions of Fyn modulator pathways and rely on analogous readouts, rather than threshold effects, known to underlie excitotoxic signaling.
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Affiliation(s)
- Hansen Wang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Tanz Neuroscience Building, 6 Queen's Park Crescent West, Toronto, Ontario M5S 3H2, Canada
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20
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Llorens F, Carulla P, Villa A, Torres JM, Fortes P, Ferrer I, del Río JA. PrP(C) regulates epidermal growth factor receptor function and cell shape dynamics in Neuro2a cells. J Neurochem 2013; 127:124-38. [PMID: 23638794 DOI: 10.1111/jnc.12283] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 04/26/2013] [Accepted: 04/27/2013] [Indexed: 01/28/2023]
Abstract
The prion protein (PrP) plays a key role in prion disease pathogenesis. Although the misfolded and pathologic variant of this protein (PrP(SC)) has been studied in depth, the physiological role of PrP(C) remains elusive and controversial. PrP(C) is a cell-surface glycoprotein involved in multiple cellular functions at the plasma membrane, where it interacts with a myriad of partners and regulates several intracellular signal transduction cascades. However, little is known about the gene expression changes modulated by PrP(C) in animals and in cellular models. In this article, we present PrP(C)-dependent gene expression signature in N2a cells and its implication in the most overrepresented functions: cell cycle, cell growth and proliferation, and maintenance of cell shape. PrP(C) over-expression enhances cell proliferation and cell cycle re-entrance after serum stimulation, while PrP(C) silencing slows down cell cycle progression. In addition, MAP kinase and protein kinase B (AKT) pathway activation are under the regulation of PrP(C) in asynchronous cells and following mitogenic stimulation. These effects are due in part to the modulation of epidermal growth factor receptor (EGFR) by PrP(C) in the plasma membrane, where the two proteins interact in a multimeric complex. We also describe how PrP(C) over-expression modulates filopodia formation by Rho GTPase regulation mainly in an AKT-Cdc42-N-WASP-dependent pathway.
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Affiliation(s)
- Franc Llorens
- Molecular and Cellular Neurobiotechnology Group, Institute for Bioengineering of Catalonia (IBEC), Barcelona Science Park, Barcelona, Spain; Department of Cell Biology, University of Barcelona (UB), Barcelona, Spain; Center for Networker Biomedical Research in Neurodegenerative Diseases (CIBERNED), Barcelona, Spain; Institute of Neuropathology, Bellvitge Biomedical Research Institute, Hospitalet de Llobregat, Spain
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21
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Zhou J, Liu B. Alzheimer's disease and prion protein. Intractable Rare Dis Res 2013; 2:35-44. [PMID: 25343100 PMCID: PMC4204584 DOI: 10.5582/irdr.2013.v2.2.35] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 05/20/2013] [Accepted: 05/22/2013] [Indexed: 11/05/2022] Open
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disease with progressive loss of memory and cognitive function, pathologically hallmarked by aggregates of the amyloid-beta (Aβ) peptide and hyperphosphorylated tau in the brain. Aggregation of Aβ under the form of amyloid fibrils has long been considered central to the pathogenesis of AD. However, recent evidence has indicated that soluble Aβ oligomers, rather than insoluble fibrils, are the main neurotoxic species in AD. The cellular prion protein (PrP(C)) has newly been identified as a cell surface receptor for Aβ oligomers. PrP(C) is a cell surface glycoprotein that plays a key role in the propagation of prions, proteinaceous infectious agents that replicate by imposing their abnormal conformation to PrP(C) molecules. In AD, PrP(C) acts to transduce the neurotoxic signals arising from Aβ oligomers, leading to synaptic failure and cognitive impairment. Interestingly, accumulating evidence has also shown that aggregated Aβ or tau possesses prion-like activity, a property that would allow them to spread throughout the brain. In this article, we review recent findings regarding the function of PrP(C) and its role in AD, and discuss potential therapeutic implications of PrP(C)-based approaches in the treatment of AD.
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Affiliation(s)
- Jiayi Zhou
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
- Address correspondence to: Dr. Jiayi Zhou, Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA. E-mail:
| | - Bingqian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
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22
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PrP octarepeats region determined the interaction with caveolin-1 and phosphorylation of caveolin-1 and Fyn. Med Microbiol Immunol 2013; 202:215-27. [PMID: 23283514 DOI: 10.1007/s00430-012-0284-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 12/12/2012] [Indexed: 01/15/2023]
Abstract
Caveolin-1 is one of the major constituents of caveolae. Both Cav-1 and PrP are plasma membrane proteins, which show active capacities for molecular interactions with many other proteins or agents, including themselves. Using yeast two-hybrid system and immunoprecipitation, we reconfirmed the molecular interaction between human Cav-1 and PrP. With co-immunoprecipitation tests, PrP(C)-Cav-1 and PrP(Sc)-Cav-1 complexes were identified in the brain homogenates of normal and scrapie agent 263K-infected hamsters, respectively. Transient expression of wild-type PrP (PrP-PG5) in HEK293 cells did not change the situation of Cav-1 and subsequent signal transduction pathways, while cross-linking of the expressed PrP with specific antibody induced remarkable colocalization of PrP and Cav-1 on the plasma membrane and significant increases of phosphorylated Cav-1 and phosphorylated Fyn. With deleted and inserted PrP mutants within octarepeat region, we observed obvious octarepeat-associated phenomena, including lower binding capacity with Cav-1 in vitro, unable to co-localize with Cav-1 in the cells and to induce up-regulation of p-Cav-1 and p-Fyn when removal of octarepeats in the context of full-length PrP. Moreover, we found that treatment on HEK293 cells with fibrous form of recombinant PrP protein led to up-regulating the levels of p-Cav-1 and p-Fyn. Our data here provide strong evidence that octarepeats of PrP are critical for the interaction between PrP and Cav-1. Significant alterations in the cultured cells, either the distributions of PrP and Cav-1 morphologically or the up-regulations of p-Cav-1 and p-Fyn, induced by antibody-mediated cross-linking or fibrous forms of PrP may suggest a possible internalization process of PrP(Sc).
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23
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Grim KJ, Abcejo AJ, Barnes A, Sathish V, Smelter DF, Ford GC, Thompson MA, Prakash YS, Pabelick CM. Caveolae and propofol effects on airway smooth muscle. Br J Anaesth 2012; 109:444-53. [PMID: 22542538 DOI: 10.1093/bja/aes130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The i.v. anaesthetic propofol produces bronchodilatation. Airway relaxation involves reduced intracellular Ca(2+) ([Ca(2+)](i)) in airway smooth muscle (ASM) and lipid rafts (caveolae), and constitutional caveolin proteins regulate [Ca(2+)](i). We postulated that propofol-induced bronchodilatation involves caveolar disruption. METHODS Caveolar fractions of human ASM cells were tested for propofol content. [Ca(2+)](i) responses of ASM cells loaded with fura-2 were performed in the presence of 10 µM histamine with and without clinically relevant concentrations of propofol (10 and 30 μM and intralipid control). Effects on sarcoplasmic reticulum (SR) Ca(2+) release were evaluated in zero extracellular Ca(2+) using the blockers Xestospongin C and ryanodine. Store-operated Ca(2+) entry (SOCE) after SR depletion was evaluated using established techniques. The role of caveolin-1 in the effect of propofol was tested using small interference RNA (siRNA) suppression. Changes in intracellular signalling cascades relevant to [Ca(2+)](i) and force regulation were also evaluated. RESULTS Propofol was present in ASM caveolar fractions in substantial concentrations. Exposure to 10 or 30 µM propofol form decreased [Ca(2+)](i) peak (but not plateau) responses to histamine by ~40%, an effect persistent in zero extracellular Ca(2+). Propofol effects were absent in caveolin-1 siRNA-transfected cells. Inhibition of ryanodine receptors prevented propofol effects on [Ca(2+)](i), while propofol blunted [Ca(2+)](i) responses to caffeine. Propofol reduced SOCE, an effect also prevented by caveolin-1 siRNA. Propofol effects were associated with decreased caveolin-1 expression and extracellular signal-regulated kinase phosphorylation. CONCLUSIONS These novel data suggest a role for caveolae (specifically caveolin-1) in propofol-induced bronchodilatation. Due to its lipid nature, propofol may transiently disrupt caveolar regulation, thus altering ASM [Ca(2+)](i).
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Affiliation(s)
- K J Grim
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA
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Staubach S, Hanisch FG. Lipid rafts: signaling and sorting platforms of cells and their roles in cancer. Expert Rev Proteomics 2011; 8:263-77. [PMID: 21501018 DOI: 10.1586/epr.11.2] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Lipid rafts are defined as microdomains within the lipid bilayer of cellular membranes that assemble subsets of transmembrane or glycosylphosphatidylinisotol-anchored proteins and lipids (cholesterol and sphingolipids) and experimentally resist extraction in cold detergent (detergent-resistant membrane). These highly dynamic raft domains are essential in signaling processes and also form sorting platforms for targeted protein traffic. Lipid rafts are involved in protein endocytosis that occurs via caveolae or flotillin-dependent pathways. Non-constitutive protein components of rafts fluctuate dramatically in cancer with impacts on cell proliferation, signaling, protein trafficking, adhesion and apoptosis. This article focuses on the identification of candidate cancer-associated biomarkers in carcinoma cells using state-of-the-art proteomics.
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Affiliation(s)
- Simon Staubach
- Institute of Biochemistry II, Medical Faculty, University of Cologne, Köln, Germany
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25
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Aged PrP null mice show defective processing of neuregulins in the peripheral nervous system. Mol Cell Neurosci 2011; 47:28-35. [DOI: 10.1016/j.mcn.2011.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 02/01/2011] [Accepted: 02/10/2011] [Indexed: 12/12/2022] Open
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Tomasi V. Signal transduction in neurons: effects of cellular prion protein on fyn kinase and ERK1/2 kinase. IMMUNITY & AGEING 2010; 7 Suppl 1:S5. [PMID: 21172064 PMCID: PMC3024879 DOI: 10.1186/1742-4933-7-s1-s5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Background It has been reported that cellular prion protein (PrPc) co-localizes with caveolin-1 and participates to signal transduction events by recruiting Fyn kinase. As PrPc is a secreted protein anchored to the outer surface membrane through a glycosylphosphatidylinositol (GPI) anchor (secPrP) and caveolin-1 is located in the inner leaflet of plasma membrane, there is a problem of how the two proteins can physically interact each other and transduce signals. Results By using the GST-fusion proteins system we observed that PrPc strongly interacts with caveolin-1 scaffolding domain and with a caveolin-1 hydrophilic C-terminal region, but not with the caveolin-1 N-terminal region. In vitro binding experiments were also performed to define the site(s) of PrPc interacting with cav-1. The results are consistent with a participation of PrPc octapeptide repeats motif in the binding to caveolin-1 scaffolding domain. The caveolar localization of PrPc was ascertained by co-immunoprecipitation, by co-localization after flotation in density gradients and by confocal microscopy analysis of PrPc and caveolin-1 distributions in a neuronal cell line (GN11) expressing caveolin-1 at high levels. Conclusions We observed that, after antibody-mediated cross-linking or copper treatment, PrPc was internalized probably into caveolae. We propose that following translocation from rafts to caveolae or caveolae-like domains, secPrP could interact with caveolin-1 and induce signal transduction events.
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Affiliation(s)
- Vittorio Tomasi
- Department of Experimental Biology, University of Bologna Via Selmi, 3 40126 - Bologna, Italy.
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Corsaro A, Thellung S, Bucciarelli T, Scotti L, Chiovitti K, Villa V, D'Arrigo C, Aceto A, Florio T. High hydrophobic amino acid exposure is responsible of the neurotoxic effects induced by E200K or D202N disease-related mutations of the human prion protein. Int J Biochem Cell Biol 2010; 43:372-82. [PMID: 21094273 DOI: 10.1016/j.biocel.2010.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 10/19/2010] [Accepted: 11/11/2010] [Indexed: 02/05/2023]
Abstract
Mutations in prion protein are thought to be causative of inherited prion diseases favoring the spontaneous conversion of the normal prion protein into the scrapie-like pathological prion protein. We previously reported that, by controlled thermal denaturation, human prion protein fragment 90-231 acquires neurotoxic properties when transformed in a β-rich conformation, resembling the scrapie-like conformation. In this study we generated prion protein fragment 90-231 bearing mutations identified in familial prion diseases (D202N and E200K), to analyze their role in the induction of a neurotoxic conformation. Prion protein fragment 90-231(wild type) and the D202N mutant were not toxic in native conformation but induced cell death only after thermal denaturation. Conversely, prion protein fragment 90-231(E200K) was highly toxic in its native structure, suggesting that E200K mutation per se favors the acquisition of a peptide neurotoxic conformation. To identify the structural determinants of prion protein fragment 90-231 toxicity, we show that while the wild type peptide is structured in α-helix, hPrP90-231 E200K is spontaneously refolded in a β-structured conformer characterized by increased proteinase K resistance and propensity to generate fibrils. However, the most significant difference induced by E200K mutation in prion protein fragment 90-231 structure in native conformation we observed, was an increase in the exposure of hydrophobic amino-acids on protein surface that was detected in wild type and D202N proteins only after thermal denaturation. In conclusion, we propose that increased hydrophobicity is one of the main determinants of toxicity induced by different mutations in prion protein-derived peptides.
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Affiliation(s)
- Alessandro Corsaro
- Laboratory of Pharmacology, Dept. Oncology, Biology and Genetics, University of Genova, Genova, Italy
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28
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Caveolin regulation of neuronal intracellular signaling. Cell Mol Life Sci 2010; 67:3785-95. [PMID: 20632068 DOI: 10.1007/s00018-010-0447-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 06/01/2010] [Accepted: 06/24/2010] [Indexed: 01/25/2023]
Abstract
Caveolin proteins physically interact with and compartmentalize membrane-localized signaling proteins to facilitate high-fidelity intracellular signaling. Though primarily studied outside the nervous system, recent investigations have revealed that caveolin proteins are key modulators of a variety of neuronal intracellular signaling pathways. Through both protein aggregation and segregation, caveolin proteins can exert positive and negative influences on intracellular signaling. This review will detail recent findings regarding caveolin function in the brain.
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29
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Sy MS, Li C, Yu S, Xin W. The fatal attraction between pro-prion and filamin A: prion as a marker in human cancers. Biomark Med 2010. [PMID: 20550479 DOI: 10.2217/bmm.10.14]available] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pancreatic cancer is the fourth leading cancer causing deaths in the USA, with more than 30,000 deaths per year. The overall median survival for all pancreatic cancer is 6 months and the 5-year survival rate is less than 10%. This dismal outcome reflects the inefficacy of the chemotherapeutic agents, as well as the lack of an early diagnostic marker. A protein known as prion (PrP) is expressed in human pancreatic cancer cell lines. However, in these cell lines, the PrP is incompletely processed and exists as pro-PrP. The pro-PrP binds to a molecule inside the cell, filamin A (FLNa), which is an integrator of cell signaling and mechanics. The binding of pro-PrP to FLNa disrupts the normal functions of FLNa, altering the cell's cytoskeleton and signal transduction machineries. As a result, the tumor cells grow more aggressively. Approximately 40% of patients with pancreatic cancer express PrP in their cancer. These patients have significantly shorter survival compared with patients whose pancreatic cancers lack PrP. Therefore, expression of pro-PrP and its binding to FLNa provide a growth advantage to pancreatic cancers. In this article, we discuss the following points: the biology of PrP, the consequences of binding of pro-PrP to FLNa in pancreatic cancer, the detection of pro-PrP in other cancers, the potential of using pro-PrP as a diagnostic marker, and prevention of the binding between pro-PrP and FLNa as a target for therapeutic intervention in cancers.
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Affiliation(s)
- Man-Sun Sy
- Department of Pathology, School of Medicine, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA.
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30
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Sy MS, Li C, Yu S, Xin W. The fatal attraction between pro-prion and filamin A: prion as a marker in human cancers. Biomark Med 2010; 4:453-64. [PMID: 20550479 PMCID: PMC2925173 DOI: 10.2217/bmm.10.14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Pancreatic cancer is the fourth leading cancer causing deaths in the USA, with more than 30,000 deaths per year. The overall median survival for all pancreatic cancer is 6 months and the 5-year survival rate is less than 10%. This dismal outcome reflects the inefficacy of the chemotherapeutic agents, as well as the lack of an early diagnostic marker. A protein known as prion (PrP) is expressed in human pancreatic cancer cell lines. However, in these cell lines, the PrP is incompletely processed and exists as pro-PrP. The pro-PrP binds to a molecule inside the cell, filamin A (FLNa), which is an integrator of cell signaling and mechanics. The binding of pro-PrP to FLNa disrupts the normal functions of FLNa, altering the cell's cytoskeleton and signal transduction machineries. As a result, the tumor cells grow more aggressively. Approximately 40% of patients with pancreatic cancer express PrP in their cancer. These patients have significantly shorter survival compared with patients whose pancreatic cancers lack PrP. Therefore, expression of pro-PrP and its binding to FLNa provide a growth advantage to pancreatic cancers. In this article, we discuss the following points: the biology of PrP, the consequences of binding of pro-PrP to FLNa in pancreatic cancer, the detection of pro-PrP in other cancers, the potential of using pro-PrP as a diagnostic marker, and prevention of the binding between pro-PrP and FLNa as a target for therapeutic intervention in cancers.
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Affiliation(s)
- Man-Sun Sy
- Department of Pathology, School of Medicine, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA.
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31
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Bremer J, Baumann F, Tiberi C, Wessig C, Fischer H, Schwarz P, Steele AD, Toyka KV, Nave KA, Weis J, Aguzzi A. Axonal prion protein is required for peripheral myelin maintenance. Nat Neurosci 2010; 13:310-8. [PMID: 20098419 DOI: 10.1038/nn.2483] [Citation(s) in RCA: 292] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 12/16/2009] [Indexed: 12/15/2022]
Abstract
The integrity of peripheral nerves relies on communication between axons and Schwann cells. The axonal signals that ensure myelin maintenance are distinct from those that direct myelination and are largely unknown. Here we show that ablation of the prion protein PrP(C) triggers a chronic demyelinating polyneuropathy (CDP) in four independently targeted mouse strains. Ablation of the neighboring Prnd locus, or inbreeding to four distinct mouse strains, did not modulate the CDP. CDP was triggered by depletion of PrP(C) specifically in neurons, but not in Schwann cells, and was suppressed by PrP(C) expression restricted to neurons but not to Schwann cells. CDP was prevented by PrP(C) variants that undergo proteolytic amino-proximal cleavage, but not by variants that are nonpermissive for cleavage, including secreted PrP(C) lacking its glycolipid membrane anchor. These results indicate that neuronal expression and regulated proteolysis of PrP(C) are essential for myelin maintenance.
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Affiliation(s)
- Juliane Bremer
- Institute of Neuropathology, University Hospital of Zürich, Zürich, Switzerland
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32
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Sorgato MC, Peggion C, Bertoli A. Is, indeed, the prion protein a Harlequin servant of "many" masters? Prion 2009; 3:202-5. [PMID: 19887913 DOI: 10.4161/pri.3.4.10012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Tens of putative interacting partners of the cellular prion protein (PrP(C)) have been identified, yet the physiologic role of PrP(C) remains unclear. For the first time, however, a recent paper has demonstrated that the absence of PrP(C) produces a lethal phenotype. Starting from this evidence, here we discuss the validity of past and more recent literature supporting that, as part of protein platforms at the cell surface, PrP(C) may bridge extracellular matrix molecules and/or membrane proteins to intracellular signaling pathways.
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Affiliation(s)
- M Catia Sorgato
- Department of Biological Chemistry and CNR Institute of Neuroscience, University of Padova, Padova, Italy
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33
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Functionally relevant domains of the prion protein identified in vivo. PLoS One 2009; 4:e6707. [PMID: 19738901 PMCID: PMC2733036 DOI: 10.1371/journal.pone.0006707] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 07/22/2009] [Indexed: 01/26/2023] Open
Abstract
The prion consists essentially of PrP(Sc), a misfolded and aggregated conformer of the cellular protein PrP(C). Whereas PrP(C) deficient mice are clinically healthy, expression of PrP(C) variants lacking its central domain (PrP(DeltaCD)), or of the PrP-related protein Dpl, induces lethal neurodegenerative syndromes which are repressed by full-length PrP. Here we tested the structural basis of these syndromes by grafting the amino terminus of PrP(C) (residues 1-134), or its central domain (residues 90-134), onto Dpl. Further, we constructed a soluble variant of the neurotoxic PrP(DeltaCD) mutant that lacks its glycosyl phosphatidyl inositol (GPI) membrane anchor. Each of these modifications abrogated the pathogenicity of Dpl and PrP(DeltaCD) in transgenic mice. The PrP-Dpl chimeric molecules, but not anchorless PrP(DeltaCD), ameliorated the disease of mice expressing truncated PrP variants. We conclude that the amino proximal domain of PrP exerts a neurotrophic effect even when grafted onto a distantly related protein, and that GPI-linked membrane anchoring is necessary for both beneficial and deleterious effects of PrP and its variants.
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34
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Haigh CL, Lewis VA, Vella LJ, Masters CL, Hill AF, Lawson VA, Collins SJ. PrPC-related signal transduction is influenced by copper, membrane integrity and the alpha cleavage site. Cell Res 2009; 19:1062-78. [PMID: 19597535 DOI: 10.1038/cr.2009.86] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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35
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Pantera B, Bini C, Cirri P, Paoli P, Camici G, Manao G, Caselli A. PrPc activation induces neurite outgrowth and differentiation in PC12 cells: role for caveolin-1 in the signal transduction pathway. J Neurochem 2009; 110:194-207. [PMID: 19457127 DOI: 10.1111/j.1471-4159.2009.06123.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cellular prion protein (PrP(c)) is a ubiquitous glycoprotein, whose physiological role is poorly characterized. It has been suggested that PrP(c) participates in neuritogenesis, neuroprotection, copper metabolism, and signal transduction. In this study we detailed the intracellular events induced by PrP(c) antibody-mediated cross-linking in PC12 cells. We found a Fyn-dependent activation of the Ras-Raf pathway, which leads to a rapid and transient phosphorylation of extracellular regulated kinases. In addition, this activation cascade relies on the engagement of integrins, and involves focal adhesion kinase activation. We demonstrated the tyrosine phosphorylation of caveolin-1 as a consequence of PrP(c) stimulation, and showed that phosphocaveolin-1 scaffolds and coordinates protein complexes involved in PrP(c)-dependent signaling. Moreover, we found that caveolin-1 phosphorylation, is a mechanism for recruiting the C-terminal Src kinase and inactivating Fyn, so as to terminate cell signaling. Furthermore our data support a significant role for PrP(c) as a response mediator in neuritogenesis and cell differentiation.
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Affiliation(s)
- Barbara Pantera
- Dipartimento di Scienze Biochimiche, Università degli Studi di Firenze, Italy
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36
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Affiliation(s)
- Adriano Aguzzi
- Institute of Neuropathology, University of Zurich, CH-8091 Zurich, Switzerland,
| | - Frank Baumann
- Institute of Neuropathology, University of Zurich, CH-8091 Zurich, Switzerland,
| | - Juliane Bremer
- Institute of Neuropathology, University of Zurich, CH-8091 Zurich, Switzerland,
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37
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Abstract
Studies on the structure and function of caveolae have revealed how this versatile subcellular organelle can influence numerous signalling pathways. This brief review will discuss a few of the key features of caveolae as it relates to signalling and disease processes.
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Affiliation(s)
- Candice M Thomas
- Department of Pediatrics and the Kentucky Pediatric Research Institute, University of Kentucky, Lexington, KY, USA
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38
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Bedecs K. Cell culture models to unravel prion protein function and aberrancies in prion diseases. Methods Mol Biol 2008; 459:1-20. [PMID: 18576144 DOI: 10.1007/978-1-59745-234-2_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
From an early stage of prion research, tissue cultures that could support and propagate the scrapie agent were sought after. The earliest attempts were explants from brains of infected mice, and their growth and morphological characteristics were compared with those from uninfected mice. Using the explant technique, several investigators reported increased cell growth in cultures established from scrapie-sick brain compared with cultures from normal mice. These are odd findings in the light of the massive neuronal cell death known to occur in scrapie-infected brains; however, the cell types responsible for the increased cell growth in the scrapie-explants most probably were not neuronal. The first successful cell culture established in this way, in which the scrapie agent was serially and continuously passaged beyond the initial explant, was in the scrapie mouse brain culture, which is still used today. This chapter describes the generation and use of chronically prion-infected cell lines as cell culture models of prion diseases. These cell lines have been crucial for the current understanding of the cell biology of both the normal (PrP(C)) and the pathogenic isoform (PrP(Sc)) of the prion protein. They also have been useful in the development of antiprion drugs, prospectively used for therapy of prion diseases, and they offer an alternative approach for transmission/infectivity assays normally performed by mouse bioassay. Cell culture models also have been used to study prion-induced cytopathological changes, which could explain the typical spongiform neurodegeneration in prion diseases.
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Affiliation(s)
- Katarina Bedecs
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
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