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Zeng WX, Liu H, Hao Y, Qian KY, Tian FM, Li L, Yu B, Zeng XT, Gao S, Hu Z, Tong XJ. CaMKII mediates sexually dimorphic synaptic transmission at neuromuscular junctions in C. elegans. J Cell Biol 2023; 222:e202301117. [PMID: 37624117 PMCID: PMC10457463 DOI: 10.1083/jcb.202301117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 06/20/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023] Open
Abstract
Sexually dimorphic behaviors are ubiquitous throughout the animal kingdom. Although both sex-specific and sex-shared neurons have been functionally implicated in these diverse behaviors, less is known about the roles of sex-shared neurons. Here, we discovered sexually dimorphic cholinergic synaptic transmission in C. elegans occurring at neuromuscular junctions (NMJs), with males exhibiting increased release frequencies, which result in sexually dimorphic locomotion behaviors. Scanning electron microscopy revealed that males have significantly more synaptic vesicles (SVs) at their cholinergic synapses than hermaphrodites. Analysis of previously published transcriptome identified the male-enriched transcripts and focused our attention on UNC-43/CaMKII. We ultimately show that differential accumulation of UNC-43 at cholinergic neurons controls axonal SV abundance and synaptic transmission. Finally, we demonstrate that sex reversal of all neurons in hermaphrodites generates male-like cholinergic transmission and locomotion behaviors. Thus, beyond demonstrating UNC-43/CaMKII as an essential mediator of sex-specific synaptic transmission, our study provides molecular and cellular insights into how sex-shared neurons can generate sexually dimorphic locomotion behaviors.
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Affiliation(s)
- Wan-Xin Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, Australia
| | - Yue Hao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Kang-Ying Qian
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Fu-Min Tian
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Lei Li
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, Australia
| | - Bin Yu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Xian-Ting Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, Australia
- Department of Neuroscience, City University of Hong Kong, Kowloon, China
| | - Xia-Jing Tong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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Wang J, Joseph S, Vingill S, Dere E, Tatenhorst L, Ronnenberg A, Lingor P, Preisinger C, Ehrenreich H, Schulz JB, Stegmüller J. Loss of the parkinsonism-associated protein FBXO7 in glutamatergic forebrain neurons in mice leads to abnormal motor behavior and synaptic defects. J Neurochem 2023; 167:296-317. [PMID: 37753846 DOI: 10.1111/jnc.15962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/28/2023]
Abstract
Mutations in PARK15, which encodes for the F-box protein FBXO7 have been associated with Parkinsonian Pyramidal syndrome, a rare and complex movement disorder with Parkinsonian symptoms, pyramidal tract signs and juvenile onset. Our previous study showed that systemic loss of Fbxo7 in mice causes motor defects and premature death. We have also demonstrated that FBXO7 has a crucial role in neurons as the specific deletion in tyrosine hydroxylase-positive or glutamatergic forebrain neurons leads to late-onset or early-onset motor dysfunction, respectively. In this study, we examined NEX-Cre;Fbxo7fl/fl mice, in which Fbxo7 was specifically deleted in glutamatergic projection neurons. The effects of FBXO7 deficiency on striatal integrity were investigated with HPLC and histological analyses. NEX-Cre;Fbxo7fl/fl mice revealed an increase in striatal dopamine concentrations, changes in the glutamatergic, GABAergic and dopaminergic pathways, astrogliosis and microgliosis and little or no neuronal loss in the striatum. To determine the effects on the integrity of the synapse, we purified synaptic membranes, subjected them to quantitative mass spectrometry analysis and found alterations in the complement system, endocytosis and exocytosis pathways. These neuropathological changes coincide with alterations in spontaneous home cage behavior. Taken together, our findings suggest that FBXO7 is crucial for corticostriatal projections and the synaptic integrity of the striatum, and consequently for proper motor control.
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Affiliation(s)
- Jingbo Wang
- Department of Neurology, RWTH University Hospital, Aachen, Germany
| | - Sabitha Joseph
- Department of Neurology, RWTH University Hospital, Aachen, Germany
| | - Siv Vingill
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Ekrem Dere
- Sorbonne Université. Institut de Biologie Paris-Seine, (IBPS), Département UMR 8256, UFR des Sciences de la Vie, Campus Pierre et Marie Curie, Paris Cedex, France
- Clinical Neuroscience, Hermann Rein Strasse 3, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Lars Tatenhorst
- Department of Neurology, University Medical Center, Göttingen, Germany
| | - Anja Ronnenberg
- Clinical Neuroscience, Hermann Rein Strasse 3, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Paul Lingor
- Department of Neurology, School of Medicine, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | | | - Hannelore Ehrenreich
- Clinical Neuroscience, Hermann Rein Strasse 3, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Jörg B Schulz
- Department of Neurology, RWTH University Hospital, Aachen, Germany
- Jülich Aachen Research Alliance (JARA)-BRAIN Institute of Molecular Neuroscience and Neuroimaging, Research Center Jülich and RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses-MultiScales, RWTH Aachen University, Aachen, Germany
| | - Judith Stegmüller
- Department of Neurology, RWTH University Hospital, Aachen, Germany
- Research Training Group 2416 MultiSenses-MultiScales, RWTH Aachen University, Aachen, Germany
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Dang X, Zhang Z, Luo XJ. Mendelian Randomization Study Using Dopaminergic Neuron-Specific eQTL Nominates Potential Causal Genes for Parkinson's Disease. Mov Disord 2022; 37:2451-2456. [PMID: 36177513 DOI: 10.1002/mds.29239] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/02/2022] [Accepted: 09/13/2022] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Large-scale genome-wide association studies (GWASs) have reported multiple risk variants for Parkinson's disease (PD). However, little is known about how these reported risk variants confer risk of PD. OBJECTIVE To nominate genes whose genetically regulated expression in dopaminergic neurons may have a causal role in PD. METHODS We conducted a two-sample Mendelian randomization (MR) study by integrating large-scale genome-wide associations and expression quantitative trait loci (eQTL) data from dopaminergic neurons. RESULTS MR analysis nominated 10 risk genes whose genetically regulated expression in dopaminergic neurons may have a causal role in PD. These MR significant genes include FAM200B, NDUFAF2, NUP42, SH3GL2, STX1B, CCDC189, KAT8, PRSS36, VAMP4, and ZSWIM7. CONCLUSIONS We report the first MR study of PD by using dopaminergic neuron-specific eQTL and nominate novel risk genes for PD. Further functional characterization of the nominated risk genes will provide mechanistic insights into PD pathogenesis and potential therapeutic targets. © 2022 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Xinglun Dang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Zhijun Zhang
- Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China.,Department of Neurology, Affiliated Zhongda Hospital, Institution of Neuropsychiatry, Southeast University, Nanjing, China.,Department of Mental Health and Public Health, Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Xiong-Jian Luo
- Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Southeast University, Nanjing, China.,Department of Neurology, Affiliated Zhongda Hospital, Institution of Neuropsychiatry, Southeast University, Nanjing, China
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4
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Lim HK, Kim K, Son YK, Nah SY, Ahn SM, Song M. Gintonin stimulates dendritic growth in striatal neurons by activating Akt and CREB. Front Mol Neurosci 2022; 15:1014497. [PMID: 36385759 PMCID: PMC9643712 DOI: 10.3389/fnmol.2022.1014497] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/04/2022] [Indexed: 09/26/2023] Open
Abstract
Gintonin, a glycolipid protein conjugated with lysophosphatidic acid (LPA), is a newly identified compound extracted from Korean ginseng. LPA receptor isotypes exhibit high affinity for gintonin and mediate intracellular calcium signaling in various animal cell models. In this study, we found that gintonin induced the activation of Akt and cAMP-response element binding protein (CREB) in mouse striatal neurons, and chronic treatment with gintonin potently induced dendritic growth and filopodia formation. Gintonin-induced Akt/CREB activation and dendritic development were significantly impaired by LPA receptor (LPAR1/3) inhibition with Ki16425. Intriguingly, prolonged treatment with gintonin ameliorated the reduction in dendritic formation caused by Shank3 and Slitrk5 deficiency in the striatal neurons. In addition, gintonin and brain-derived neurotrophic factor (BDNF) had a synergistic effect on AKT/CREB activation and dendritic growth at suboptimal concentrations. These findings imply that gintonin-stimulated LPA receptors play a role in dendritic growth in striatal neurons and that they may act synergistically with BDNF, which is known to play a role in dendritogenesis.
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Affiliation(s)
- Hye Kyung Lim
- Department of Life Sciences, Yeungnam University, Gyeongsan, South Korea
| | - Kitaek Kim
- Department of Life Sciences, Yeungnam University, Gyeongsan, South Korea
| | - Youn Kyoung Son
- National Institute of Biological Resources, Incheon, South Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, South Korea
| | - Soo Min Ahn
- Department of Pediatric Surgery, Metabolic and Bariatric Surgery Center, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Minseok Song
- Department of Life Sciences, Yeungnam University, Gyeongsan, South Korea
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Tanguy E, Wolf A, Montero-Hadjadje M, Gasman S, Bader MF, Vitale N. Phosphatidic acid: Mono- and poly-unsaturated forms regulate distinct stages of neuroendocrine exocytosis. Adv Biol Regul 2020; 79:100772. [PMID: 33288473 DOI: 10.1016/j.jbior.2020.100772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/16/2020] [Accepted: 11/25/2020] [Indexed: 10/22/2022]
Abstract
Lipids have emerged as important actors in an ever-growing number of key functions in cell biology over the last few years. Among them, glycerophospholipids are major constituents of cellular membranes. Because of their amphiphilic nature, phospholipids form lipid bilayers that are particularly useful to isolate cellular content from the extracellular medium, but also to define intracellular compartments. Interestingly, phospholipids come in different flavors based on their fatty acyl chain composition. Indeed, lipidomic analyses have revealed the presence in cellular membranes of up to 50 different species of an individual class of phospholipid, opening the possibility of multiple functions for a single class of phospholipid. In this review we will focus on phosphatidic acid (PA), the simplest phospholipid, that plays both structural and signaling functions. Among the numerous roles that have been attributed to PA, a key regulatory role in secretion has been proposed in different cell models. We review here the evidences that support the idea that mono- and poly-unsaturated PA control distinct steps in hormone secretion from neuroendocrine cells.
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Affiliation(s)
- Emeline Tanguy
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Alexander Wolf
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Maité Montero-Hadjadje
- Normandie Univ, UNIROUEN, INSERM, U1239, Laboratoire de Différenciation et Communication Neuronale et Neuroendocrine, Institut de Recherche et d'Innovation Biomédicale de Normandie, 76000, Rouen, France
| | - Stéphane Gasman
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Marie-France Bader
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France
| | - Nicolas Vitale
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, F-67000 Strasbourg, France.
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6
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Alpha-Synuclein and LRRK2 in Synaptic Autophagy: Linking Early Dysfunction to Late-Stage Pathology in Parkinson's Disease. Cells 2020; 9:cells9051115. [PMID: 32365906 PMCID: PMC7290471 DOI: 10.3390/cells9051115] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 12/24/2022] Open
Abstract
The lack of effective disease-modifying strategies is the major unmet clinical need in Parkinson’s disease. Several experimental approaches have attempted to validate cellular targets and processes. Of these, autophagy has received considerable attention in the last 20 years due to its involvement in the clearance of pathologic protein aggregates and maintenance of neuronal homeostasis. However, this strategy mainly addresses a very late stage of the disease, when neuropathology and neurodegeneration have likely “tipped over the edge” and disease modification is extremely difficult. Very recently, autophagy has been demonstrated to modulate synaptic activity, a process distinct from its catabolic function. Abnormalities in synaptic transmission are an early event in neurodegeneration with Leucine-Rich Repeat Kinase 2 (LRRK2) and alpha-synuclein strongly implicated. In this review, we analyzed these processes separately and then discussed the unification of these biomolecular fields with the aim of reconstructing a potential “molecular timeline” of disease onset and progression. We postulate that the elucidation of these pathogenic mechanisms will form a critical basis for the design of novel, effective disease-modifying therapies that could be applied early in the disease process.
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7
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Wruck W, Adjaye J. Meta-analysis of human prefrontal cortex reveals activation of GFAP and decline of synaptic transmission in the aging brain. Acta Neuropathol Commun 2020; 8:26. [PMID: 32138778 PMCID: PMC7059712 DOI: 10.1186/s40478-020-00907-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/01/2020] [Indexed: 12/14/2022] Open
Abstract
Despite ongoing research efforts, mechanisms of brain aging are still enigmatic and need to be elucidated for a better understanding of age-associated cognitive decline. The aim of this study is to investigate aging in the prefrontal cortex region of human brain in a meta-analysis of transcriptome datasets. We analyzed 591 gene expression datasets pertaining to female and male human prefrontal cortex biopsies of distinct ages. We used hierarchical clustering and principal component analysis (PCA) to determine the influence of sex and age on global transcriptome levels. In sex-specific analysis we identified genes correlating with age and differentially expressed between groups of young, middle-aged and aged. Pathways and gene ontologies (GOs) over-represented in the resulting gene sets were calculated. Potential causal relationships between genes and between GOs were explored employing the Granger test of gene expression time series over the range of ages. The most outstanding results were the age-related decline of synaptic transmission and activated expression of glial fibrillary acidic protein (GFAP) in both sexes. We found an antagonistic relationship between calcium/calmodulin dependent protein kinase IV (CAMK4) and GFAP which may include regulatory mechanisms involving cAMP responsive element binding protein (CREB) and mitogen-activated protein kinase (MAPK, alias ERK). Common to both sexes was a decline in synaptic transmission, neurogenesis and an increased base-level of inflammatory and immune-related processes. Furthermore, we detected differences in dendritic spine morphogenesis, catecholamine signaling and cellular responses to external stimuli, particularly to metal (Zinc and cadmium) ions which were higher in female brains.
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8
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Division and Adaptation to Host Environment of Apicomplexan Parasites Depend on Apicoplast Lipid Metabolic Plasticity and Host Organelle Remodeling. Cell Rep 2020; 30:3778-3792.e9. [DOI: 10.1016/j.celrep.2020.02.072] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 11/12/2019] [Accepted: 02/19/2020] [Indexed: 11/20/2022] Open
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9
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Zečić A, Dhondt I, Braeckman BP. The nutritional requirements of Caenorhabditis elegans. GENES AND NUTRITION 2019; 14:15. [PMID: 31080524 PMCID: PMC6501307 DOI: 10.1186/s12263-019-0637-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 04/10/2019] [Indexed: 12/14/2022]
Abstract
Animals require sufficient intake of a variety of nutrients to support their development, somatic maintenance and reproduction. An adequate diet provides cell building blocks, chemical energy to drive cellular processes and essential nutrients that cannot be synthesised by the animal, or at least not in the required amounts. Dietary requirements of nematodes, including Caenorhabditis elegans have been extensively studied with the major aim to develop a chemically defined axenic medium that would support their growth and reproduction. At the same time, these studies helped elucidating important aspects of nutrition-related biochemistry and metabolism as well as the establishment of C. elegans as a powerful model in studying evolutionarily conserved pathways, and the influence of the diet on health.
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Affiliation(s)
- Aleksandra Zečić
- Department of Biology, Laboratory of Aging Physiology and Molecular Evolution, Ghent University, 9000 Ghent, Belgium
| | - Ineke Dhondt
- Department of Biology, Laboratory of Aging Physiology and Molecular Evolution, Ghent University, 9000 Ghent, Belgium
| | - Bart P Braeckman
- Department of Biology, Laboratory of Aging Physiology and Molecular Evolution, Ghent University, 9000 Ghent, Belgium
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10
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Alecu I, Bennett SAL. Dysregulated Lipid Metabolism and Its Role in α-Synucleinopathy in Parkinson's Disease. Front Neurosci 2019; 13:328. [PMID: 31031582 PMCID: PMC6470291 DOI: 10.3389/fnins.2019.00328] [Citation(s) in RCA: 143] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/21/2019] [Indexed: 12/23/2022] Open
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease, the main pathological hallmark of which is the accumulation of α-synuclein (α-syn) and the formation of filamentous aggregates called Lewy bodies in the brainstem, limbic system, and cortical areas. Lipidomics is a newly emerging field which can provide fresh insights and new answers that will enhance our capacity for early diagnosis, tracking disease progression, predicting critical endpoints, and identifying risk in pre-symptomatic persons. In recent years, lipids have been implicated in many aspects of PD pathology. Biophysical and lipidomic studies have demonstrated that α-syn binds preferentially not only to specific lipid families but also to specific molecular species and that these lipid-protein complexes enhance its interaction with synaptic membranes, influence its oligomerization and aggregation, and interfere with the catalytic activity of cytoplasmic lipid enzymes and lysosomal lipases, thereby affecting lipid metabolism. The genetic link between aberrant lipid metabolism and PD is even more direct, with mutations in GBA and SMPD1 enhancing PD risk in humans and loss of GALC function increasing α-syn aggregation and accumulation in experimental murine models. Moreover, a number of lipidomic studies have reported PD-specific lipid alterations in both patient brains and plasma, including alterations in the lipid composition of lipid rafts in the frontal cortex. A further aspect of lipid dysregulation promoting PD pathogenesis is oxidative stress and inflammation, with proinflammatory lipid mediators such as platelet activating factors (PAFs) playing key roles in arbitrating the progressive neurodegeneration seen in PD linked to α-syn intracellular trafficking. Lastly, there are a number of genetic risk factors of PD which are involved in normal lipid metabolism and function. Genes such as PLA2G6 and SCARB2, which are involved in glycerophospholipid and sphingolipid metabolism either directly or indirectly are associated with risk of PD. This review seeks to describe these facets of metabolic lipid dysregulation as they relate to PD pathology and potential pathomechanisms involved in disease progression, while highlighting incongruous findings and gaps in knowledge that necessitate further research.
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Affiliation(s)
- Irina Alecu
- Neural Regeneration Laboratory, Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
- Department of Chemistry and Biomolecular Sciences, Centre for Catalysis and Research Innovation, University of Ottawa, Ottawa, ON, Canada
| | - Steffany A. L. Bennett
- Neural Regeneration Laboratory, Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
- Department of Chemistry and Biomolecular Sciences, Centre for Catalysis and Research Innovation, University of Ottawa, Ottawa, ON, Canada
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11
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Lee W, Kim SH. Autophagy at synapses in neurodegenerative diseases. Arch Pharm Res 2019; 42:407-415. [DOI: 10.1007/s12272-019-01148-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 03/21/2019] [Indexed: 12/31/2022]
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12
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Barriga HMG, Holme MN, Stevens MM. Cubosomes: The Next Generation of Smart Lipid Nanoparticles? Angew Chem Int Ed Engl 2019; 58:2958-2978. [PMID: 29926520 PMCID: PMC6606436 DOI: 10.1002/anie.201804067] [Citation(s) in RCA: 273] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/12/2018] [Indexed: 12/13/2022]
Abstract
Cubosomes are highly stable nanoparticles formed from the lipid cubic phase and stabilized by a polymer based outer corona. Bicontinuous lipid cubic phases consist of a single lipid bilayer that forms a continuous periodic membrane lattice structure with pores formed by two interwoven water channels. Cubosome composition can be tuned to engineer pore sizes or include bioactive lipids, the polymer outer corona can be used for targeting and they are highly stable under physiological conditions. Compared to liposomes, the structure provides a significantly higher membrane surface area for loading of membrane proteins and small drug molecules. Owing to recent advances, they can be engineered in vitro in both bulk and nanoparticle formats with applications including drug delivery, membrane bioreactors, artificial cells, and biosensors. This review outlines recent advances in cubosome technology enabling their application and provides guidelines for the rational design of new systems for biomedical applications.
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Affiliation(s)
- Hanna M. G. Barriga
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Margaret N. Holme
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Molly M. Stevens
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- Departments of Materials and Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, UK
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13
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Mitochondrial Dynamics in Stem Cells and Differentiation. Int J Mol Sci 2018; 19:ijms19123893. [PMID: 30563106 PMCID: PMC6321186 DOI: 10.3390/ijms19123893] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/03/2018] [Accepted: 12/04/2018] [Indexed: 01/09/2023] Open
Abstract
Mitochondria are highly dynamic organelles that continuously change their shape. Their main function is adenosine triphosphate (ATP) production; however, they are additionally involved in a variety of cellular phenomena, such as apoptosis, cell cycle, proliferation, differentiation, reprogramming, and aging. The change in mitochondrial morphology is closely related to the functionality of mitochondria. Normal mitochondrial dynamics are critical for cellular function, embryonic development, and tissue formation. Thus, defects in proteins involved in mitochondrial dynamics that control mitochondrial fusion and fission can affect cellular differentiation, proliferation, cellular reprogramming, and aging. Here, we review the processes and proteins involved in mitochondrial dynamics and their various associated cellular phenomena.
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14
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Meng XY, Kang SG, Zhou R. Molecular mechanism of phosphoinositides' specificity for the inwardly rectifying potassium channel Kir2.2. Chem Sci 2018; 9:8352-8362. [PMID: 30542582 PMCID: PMC6247517 DOI: 10.1039/c8sc01284a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 09/04/2018] [Indexed: 12/04/2022] Open
Abstract
We investigated the binding mechanism of PI(4,5)P2 and variants on the inwardly rectifying potassium channel, Kir2.2. Our results not only demonstrated the molecular origin for their binding specificity, but also revealed the major driving forces.
Phosphoinositides are essential signaling lipids that play a critical role in regulating ion channels, and their dysregulation often results in fatal diseases including cardiac arrhythmia and paralysis. Despite decades of intensive research, the underlying molecular mechanism of lipid agonism and specificity remains largely unknown. Here, we present a systematic study of the binding mechanism and specificity of a native agonist, phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and two of its variants, PI(3,4)P2 and PI(3,4,5)P3, on inwardly rectifying potassium channel Kir2.2, using molecular dynamics simulations and free energy perturbations (FEPs). Our results demonstrate that the major driving force for the PI(4,5)P2 specificity on Kir2.2 comes from the highly organized salt-bridge network formed between the charged inositol head and phosphodiester linker of PI(4,5)P2. The unsaturated arachidonic chain is also shown to contribute to the stable binding through hydrophobic interactions with nearby Kir2.2 hydrophobic residues. Consistent with previous experimental findings, our FEP results confirmed that non-native ligands, PI(3,4)P2 and PI(3,4,5)P3, show significant loss in binding affinity as a result of the substantial shift from the native binding mode and unfavorable local solvation environment. However, surprisingly, the underlying molecular pictures for the unfavorable binding of both ligands are quite distinctive: for PI(3,4)P2, it is due to a direct destabilization in the bound state, whereas for PI(3,4,5)P3, it is due to a relative stabilization in its free state. Our findings not only provide a theoretical basis for the ligand specificity, but also generate new insights into the allosteric modulation of ligand-gated ion channels.
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Affiliation(s)
- Xuan-Yu Meng
- State Key Laboratory of Radiation Medicine and Protection , School for Radiological and Interdisciplinary Sciences (RAD-X) , Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions , Soochow University , Suzhou 215123 , China
| | - Seung-Gu Kang
- IBM Thomas J. Watson Research Center , Yorktown Heights , NY 10598 , USA .
| | - Ruhong Zhou
- State Key Laboratory of Radiation Medicine and Protection , School for Radiological and Interdisciplinary Sciences (RAD-X) , Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions , Soochow University , Suzhou 215123 , China.,IBM Thomas J. Watson Research Center , Yorktown Heights , NY 10598 , USA . .,Department of Chemistry , Columbia University , New York , NY 10027 , USA
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15
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Barriga HMG, Holme MN, Stevens MM. Cubosomen: die nächste Generation intelligenter Lipid‐Nanopartikel? Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804067] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Hanna M. G. Barriga
- Department of Medical Biochemistry and BiophysicsKarolinska Institute Stockholm Schweden
| | - Margaret N. Holme
- Department of Medical Biochemistry and BiophysicsKarolinska Institute Stockholm Schweden
| | - Molly M. Stevens
- Department of Medical Biochemistry and BiophysicsKarolinska Institute Stockholm Schweden
- Departments of Materials and Bioengineering and Institute of Biomedical EngineeringImperial College London London Großbritannien
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16
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McDargh ZA, Deserno M. Dynamin's helical geometry does not destabilize membranes during fission. Traffic 2018; 19:328-335. [PMID: 29437294 DOI: 10.1111/tra.12555] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 02/02/2018] [Accepted: 02/04/2018] [Indexed: 11/29/2022]
Abstract
It is now widely accepted that dynamin-mediated fission is a fundamentally mechanical process: dynamin undergoes a GTP-dependent conformational change, constricting the neck between two compartments, somehow inducing their fission. However, the exact connection between dynamin's conformational change and the scission of the neck is still unclear. In this paper, we re-evaluate the suggestion that a change in the pitch or radius of dynamin's helical geometry drives the lipid bilayer through a mechanical instability, similar to a well-known phenomenon occurring in soap films. We find that, contrary to previous claims, there is no such instability. This lends credence to an alternative model, in which dynamin drives the membrane up an energy barrier, allowing thermal fluctuations to take it into the hemifission state.
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Affiliation(s)
- Zachary A McDargh
- Chemical Engineering Department, Columbia University, New York, New York
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania
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17
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He B, Zhang J, Wang Y, Li Y, Zou X, Liang B. Identification of cytochrome b5 CYTB-5.1 and CYTB-5.2 in C. elegans; evidence for differential regulation of SCD. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1863:235-246. [PMID: 29237573 DOI: 10.1016/j.bbalip.2017.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 12/02/2017] [Accepted: 12/07/2017] [Indexed: 01/04/2023]
Abstract
Unsaturated fatty acids (UFAs) play crucial roles in living organisms regarding development, energy metabolism, stress resistance, etc. The biosynthesis of UFAs starts from the introduction of the first double bond by stearoyl-CoA desaturase (SCD), converting saturated fatty acids (SFAs) to monounsaturated fatty acids (MUFAs). This desaturation is considered to be an aerobic process that requires cytochrome b5 reductase, cytochrome b5 and SCD. However, this enzyme system remains elusive in Caenorhabditis elegans. Here, we show that inactivation by RNAi knockdown or mutation (gk442189) of putative cytochrome b5 genes cytb-5.1 led to reduced conversion of C18:0 to C18:1(n-9) by SCD desaturases FAT-6/7 in C. elegans. On the contrary, cytb-5.2RNAi and cytb-5.2(gk113588) mutant worms showed decreased conversion of C16:0 to C16:1(n-7) by FAT-5 desaturase. Dietary supplementation with C18:1(n-9) and C18:2(n-6) also showed that CYTB-5.1 is likely required for the activity of FAT-6/7 desaturases, but not for FAT-1 to FAT-4 desaturases. Interestingly, co-immunoprecipitation (Co-IP) demonstrated that either FAT-7 or FAT-5 has ability to interact with both CYTB-5.1 and CYTB-5.2. Moreover, RNAi knockdown of cytb-5.1 upregulates the transcriptional and translational expression of fat-5 to fat-7, which may be due to the feedback induction by reduced C18:1(n-9) and downstream fatty acids. Furthermore, both CYTB-5.1 and CYTB-5.2 are involved in fat accumulation, fertility and lifespan in worms, which may be independent of changes in fatty acid compositions. Collectively, these findings for the first time reveal the differential regulation of various SCDs by distinct cytochrome b5 CYTB-5.1 and CYTB-5.2 in the biosynthesis of UFAs in C. elegans.
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Affiliation(s)
- Baoshen He
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Jingjing Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Department of Hepatobiliary Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, China
| | - Yanli Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Yamei Li
- School of Life Sciences, University of Science and Technology of China, Hefei 230036, China
| | - Xiaoju Zou
- Department of Life Science and Biotechnology, Key Laboratory of Special Biological Resource Development and Utilization of University in Yunnan Province, Kunming University, Kunming 650214, China.
| | - Bin Liang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China; Department of Hepatobiliary Surgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, China.
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18
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Bailey KA, Klymenko Y, Feist PE, Hummon AB, Stack MS, Schultz ZD. Chemical Analysis of Morphological Changes in Lysophosphatidic Acid-Treated Ovarian Cancer Cells. Sci Rep 2017; 7:15295. [PMID: 29127342 PMCID: PMC5681516 DOI: 10.1038/s41598-017-15547-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/30/2017] [Indexed: 12/21/2022] Open
Abstract
Ovarian cancer (OvCa) cells are reported to undergo biochemical changes at the cell surface in response to treatment with lysophosphatidic acid (LPA). Here we use scanning electron microscopy (SEM) and multiplex coherent anti-Stokes Raman scattering (CARS) imaging via supercontinuum excitation to probe morphological changes that result from LPA treatment. SEM images show distinct shedding of microvilli-like features upon treatment with LPA. Analysis of multiplex CARS images can distinguish between molecular components, such as lipids and proteins. Our results indicate that OvCa429 and SKOV3ip epithelial ovarian cancer cells undergo similar morphological and chemical responses to treatment with LPA. The microvilli-like structures on the surface of multicellular aggregates (MCAs) are removed by treatment with LPA. The CARS analysis shows a distinct decrease in protein and increase in lipid composition on the surface of LPA-treated cells. Importantly, the CARS signals from cellular sheddings from MCAs with LPA treatment are consistent with cleavage of proteins originally present. Mass spectrometry on the cellular sheddings show that a large number of proteins, both membrane and intracellular, are present. An increased number of peptides are detected for the mesenchymal cell line relative to the epithelial cell indicating a differential response to LPA treatment with cancer progression.
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Affiliation(s)
- Karen A Bailey
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Yuliya Klymenko
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
- Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, 46617, USA
| | - Peter E Feist
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Amanda B Hummon
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
- Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, 46617, USA
| | - M Sharon Stack
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
- Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, 46617, USA
| | - Zachary D Schultz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
- Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, 46617, USA.
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19
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Peñalver A, Campos-Sandoval JA, Blanco E, Cardona C, Castilla L, Martín-Rufián M, Estivill-Torrús G, Sánchez-Varo R, Alonso FJ, Pérez-Hernández M, Colado MI, Gutiérrez A, de Fonseca FR, Márquez J. Glutaminase and MMP-9 Downregulation in Cortex and Hippocampus of LPA 1 Receptor Null Mice Correlate with Altered Dendritic Spine Plasticity. Front Mol Neurosci 2017; 10:278. [PMID: 28928633 PMCID: PMC5591874 DOI: 10.3389/fnmol.2017.00278] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/17/2017] [Indexed: 12/03/2022] Open
Abstract
Lysophosphatidic acid (LPA) is an extracellular lipid mediator that regulates nervous system development and functions acting through G protein-coupled receptors (GPCRs). Here we explore the crosstalk between LPA1 receptor and glutamatergic transmission by examining expression of glutaminase (GA) isoforms in different brain areas isolated from wild-type (WT) and KOLPA1 mice. Silencing of LPA1 receptor induced a severe down-regulation of Gls-encoded long glutaminase protein variant (KGA) (glutaminase gene encoding the kidney-type isoforms, GLS) protein expression in several brain regions, particularly in brain cortex and hippocampus. Immunohistochemical assessment of protein levels for the second type of glutaminase (GA) isoform, glutaminase gene encoding the liver-type isoforms (GLS2), did not detect substantial differences with regard to WT animals. The regional mRNA levels of GLS were determined by real time RT-PCR and did not show significant variations, except for prefrontal and motor cortex values which clearly diminished in KO mice. Total GA activity was also significantly reduced in prefrontal and motor cortex, but remained essentially unchanged in the hippocampus and rest of brain regions examined, suggesting activation of genetic compensatory mechanisms and/or post-translational modifications to compensate for KGA protein deficit. Remarkably, Golgi staining of hippocampal regions showed an altered morphology of glutamatergic pyramidal cells dendritic spines towards a less mature filopodia-like phenotype, as compared with WT littermates. This structural change correlated with a strong decrease of active matrix-metalloproteinase (MMP) 9 in cerebral cortex and hippocampus of KOLPA1 mice. Taken together, these results demonstrate that LPA signaling through LPA1 influence expression of the main isoenzyme of glutamate biosynthesis with strong repercussions on dendritic spines maturation, which may partially explain the cognitive and learning defects previously reported for this colony of KOLPA1 mice.
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Affiliation(s)
- Ana Peñalver
- Canceromics Laboratory, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de TeatinosMálaga, Spain
| | - José A Campos-Sandoval
- Canceromics Laboratory, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de TeatinosMálaga, Spain
| | - Eduardo Blanco
- Unidad de Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de MálagaMálaga, Spain
| | - Carolina Cardona
- Canceromics Laboratory, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de TeatinosMálaga, Spain
| | - Laura Castilla
- Canceromics Laboratory, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de TeatinosMálaga, Spain
| | - Mercedes Martín-Rufián
- Canceromics Laboratory, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de TeatinosMálaga, Spain
| | - Guillermo Estivill-Torrús
- Unidad de Gestión Clínica de Neurociencias, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de MálagaMálaga, Spain
| | - Raquel Sánchez-Varo
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Instituto de Investigación Biomédica de Málaga (IBIMA), Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Málaga, Campus de TeatinosMálaga, Spain
| | - Francisco J Alonso
- Canceromics Laboratory, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de TeatinosMálaga, Spain
| | - Mercedes Pérez-Hernández
- Departamento de Farmacología, Facultad de Medicina, Universidad Complutense, Instituto de Investigación Sanitaria Hospital 12 de OctubreMadrid, Spain
| | - María I Colado
- Departamento de Farmacología, Facultad de Medicina, Universidad Complutense, Instituto de Investigación Sanitaria Hospital 12 de OctubreMadrid, Spain
| | - Antonia Gutiérrez
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Instituto de Investigación Biomédica de Málaga (IBIMA), Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Málaga, Campus de TeatinosMálaga, Spain
| | - Fernando Rodríguez de Fonseca
- Unidad de Gestión Clínica de Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de MálagaMálaga, Spain
| | - Javier Márquez
- Canceromics Laboratory, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de TeatinosMálaga, Spain
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20
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The inducible blockage of RNAi reveals a role for polyunsaturated fatty acids in the regulation of dsRNA-endocytic capacity in Bactrocera dorsalis. Sci Rep 2017; 7:5584. [PMID: 28717187 PMCID: PMC5514080 DOI: 10.1038/s41598-017-05971-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 06/06/2017] [Indexed: 12/12/2022] Open
Abstract
Exogenous double-stranded RNA (dsRNA) can trigger gene silencing through the RNA interference (RNAi) pathway. Our previous research established that Bactrocera dorsalis can block RNAi after an initial priming of exposure to dsRNA. However, the mechanism underlying this phenomenon is not yet fully understood. Here, we demonstrate that fatty acid biosynthesis and metabolism pathways play important roles in the blockage of RNAi induced by dsRNA priming. The ratio of linoleic acid (LA) to arachidonic acid (AA) was significantly increased in the hemolymph of B. dorsalis following dsRNA priming, and further, the endocytosis of dsRNA into the midgut cells of B. dorsalis was inhibited in these samples. The expression levels of most genes involved in the fatty acid biosynthesis and metabolism pathways were altered following priming with dsRNA. Furthermore, altering the composition of fatty acids via the injection of AA can facilitate the uptake of ingested dsRNA into the midgut cells of Drosophila melanogaster and successfully induce an RNAi effect, which cannot be achieved via feeding in fruit flies. Our results suggest that polyunsaturated fatty acids are involved in the regulation of the dsRNA-endocytic ability in B. dorsalis.
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21
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Zhu Y, Zhang X, Wang L, Ji Z, Xie M, Zhou X, Liu Z, Shi H, Yu R. Loss of SH3GL2 promotes the migration and invasion behaviours of glioblastoma cells through activating the STAT3/MMP2 signalling. J Cell Mol Med 2017; 21:2685-2694. [PMID: 28470949 PMCID: PMC5661104 DOI: 10.1111/jcmm.13184] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 03/06/2017] [Indexed: 12/22/2022] Open
Abstract
SH3GL2 (Src homology 3 (SH3) domain GRB2‐like 2) is mainly expressed in the central nervous system and regarded as a tumour suppressor in human glioma. However, the molecular mechanism of the SH3GL2 protein involved in malignant behaviours of human glioma has not been elucidated. In this study, we tried to investigate the role of SH3GL2 in glioma cell migration and invasion and explore its underlined molecular mechanism. Firstly, we discovered that the protein level of SH3GL2 was widely decreased in the human glioma patients, especially in high‐grade glioma tissues. Then, we determined the role of SH3GL2 in migration and invasion of glioma cells upon SH3GL2 knocking down and overexpressing. It was showed that knocking down of SH3GL2 promoted the migration and invasion of glioma cells, whereas overexpression of SH3GL2 inhibited them. Further study on molecular mechanism disclosed that silencing of SH3GL2 obviously activated the STAT3 (signal transducer and activator of transcription 3) signalling thereby promoting the expression and secretion of MMP2. On the contrary, overexpression of SH3GL2 had opposite effect. Taken together, the above results suggest that SH3GL2 suppresses migration and invasion behaviours of glioma cells through negatively regulating STAT3/MMP2 signalling and that loss of SH3GL2 may intensify the STAT3/MMP2 signalling thereby contributing to the migration and invasion of glioma cells.
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Affiliation(s)
- Yufu Zhu
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China.,Brain Hospital, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Xiang Zhang
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China.,The Graduate School, Xuzhou Medical University, Xuzhou, China
| | - Lei Wang
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China.,Brain Hospital, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Zhe Ji
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China.,The Graduate School, Xuzhou Medical University, Xuzhou, China
| | - Manyi Xie
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China.,Brain Hospital, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Xinyu Zhou
- The Graduate School, Xuzhou Medical University, Xuzhou, China.,Department of General Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zhiyi Liu
- The Graduate School, Xuzhou Medical University, Xuzhou, China.,Department of General Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Hengliang Shi
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China.,Brain Hospital, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Rutong Yu
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China.,Brain Hospital, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
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22
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Raben DM, Barber CN. Phosphatidic acid and neurotransmission. Adv Biol Regul 2016; 63:15-21. [PMID: 27671966 DOI: 10.1016/j.jbior.2016.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 09/15/2016] [Accepted: 09/19/2016] [Indexed: 12/31/2022]
Abstract
Lipids play a vital role in the health and functioning of neurons and interest in the physiological role of neuronal lipids is certainly increasing. One neuronal function in which neuronal lipids appears to play key roles in neurotransmission. Our understanding of the role of lipids in the synaptic vesicle cycle and neurotransmitter release is becoming increasingly more important. Much of the initial research in this area has highlighted the major roles played by the phosphoinositides (PtdIns), diacylglycerol (DAG), and phosphatidic acid (PtdOH). Of these, PtdOH has not received as much attention as the other lipids although its role and metabolism appears to be extremely important. This lipid has been shown to play a role in modulating both exocytosis and endocytosis although its precise role in either process is not well defined. The currently evidence suggest this lipid likely participates in key processes by altering membrane architecture necessary for membrane fusion, mediating the penetration of membrane proteins, serving as a precursor for other important SV cycling lipids, or activating essential enzymes. In this review, we address the sources of PtdOH, the enzymes involved in its production, the regulation of these enzymes, and its potential roles in neurotransmission in the central nervous system.
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Affiliation(s)
- Daniel M Raben
- The Department of Biological Chemistry, The Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
| | - Casey N Barber
- The Department of Biological Chemistry, The Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
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23
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Abstract
Endocytosis can be separated into the categories of phagocytosis and pinocytosis. Phagocytosis can be distinguished from pinocytosis primarily by the size of particle ingested and by its dependence on actin polymerization as a key step in particle ingestion. Several specific forms of pinocytosis have been identified that can be distinguished based on their dependence on clathrin or caveolin. Both clathrin and caveolin-dependent pinocytosis appear to require the participation of dynamin to internalize the plasma membrane. Other, less well-characterized forms of pinocytosis have also been described. Although endocytosis has long been known to affect receptor density, recent studies have demonstrated that endocytosis through clathrin- and caveolin-dependent processes plays a key role in receptor-mediated signal transduction. In some cases, blockade of these processes attenuates, or even prevents, signal transduction from taking place. This information, coupled with a better understanding of endocytosis mechanisms, will help advance the field of cell biology as well as present new targets for drug development and disease treatment.
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Affiliation(s)
- Jiang Liu
- Department of Medicine, Room 12, Ruppert Center, 3120 Glendale Avenue, Toledo, OH 43614, USA.
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24
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Freedman AH, Schweizer RM, Ortega-Del Vecchyo D, Han E, Davis BW, Gronau I, Silva PM, Galaverni M, Fan Z, Marx P, Lorente-Galdos B, Ramirez O, Hormozdiari F, Alkan C, Vilà C, Squire K, Geffen E, Kusak J, Boyko AR, Parker HG, Lee C, Tadigotla V, Siepel A, Bustamante CD, Harkins TT, Nelson SF, Marques-Bonet T, Ostrander EA, Wayne RK, Novembre J. Demographically-Based Evaluation of Genomic Regions under Selection in Domestic Dogs. PLoS Genet 2016; 12:e1005851. [PMID: 26943675 PMCID: PMC4778760 DOI: 10.1371/journal.pgen.1005851] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/18/2016] [Indexed: 12/31/2022] Open
Abstract
Controlling for background demographic effects is important for accurately identifying loci that have recently undergone positive selection. To date, the effects of demography have not yet been explicitly considered when identifying loci under selection during dog domestication. To investigate positive selection on the dog lineage early in the domestication, we examined patterns of polymorphism in six canid genomes that were previously used to infer a demographic model of dog domestication. Using an inferred demographic model, we computed false discovery rates (FDR) and identified 349 outlier regions consistent with positive selection at a low FDR. The signals in the top 100 regions were frequently centered on candidate genes related to brain function and behavior, including LHFPL3, CADM2, GRIK3, SH3GL2, MBP, PDE7B, NTAN1, and GLRA1. These regions contained significant enrichments in behavioral ontology categories. The 3rd top hit, CCRN4L, plays a major role in lipid metabolism, that is supported by additional metabolism related candidates revealed in our scan, including SCP2D1 and PDXC1. Comparing our method to an empirical outlier approach that does not directly account for demography, we found only modest overlaps between the two methods, with 60% of empirical outliers having no overlap with our demography-based outlier detection approach. Demography-aware approaches have lower-rates of false discovery. Our top candidates for selection, in addition to expanding the set of neurobehavioral candidate genes, include genes related to lipid metabolism, suggesting a dietary target of selection that was important during the period when proto-dogs hunted and fed alongside hunter-gatherers.
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Affiliation(s)
- Adam H. Freedman
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Rena M. Schweizer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Diego Ortega-Del Vecchyo
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Eunjung Han
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Brian W. Davis
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ilan Gronau
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, New York, United States of America
| | | | | | - Zhenxin Fan
- Key Laboratory of Bioresources and Ecoenvironment, Sichuan University, Chengdu, China
| | - Peter Marx
- Department of Measurement and Information Systems, Budapest University of Technology and Economics, Budapest, Hungary
| | - Belen Lorente-Galdos
- ICREA at Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Oscar Ramirez
- ICREA at Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Farhad Hormozdiari
- Department of Computer Science, University of California, Los Angeles, Los Angeles, California, United States of America
| | | | - Carles Vilà
- Estación Biológia de Doñana EBD-CSIC, Sevilla, Spain
| | - Kevin Squire
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Eli Geffen
- Department of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Josip Kusak
- Department of Biology, University of Zagreb, Zagreb, Croatia
| | - Adam R. Boyko
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
| | - Heidi G. Parker
- ICREA at Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Clarence Lee
- Life Technologies, Foster City, California, United States of America
| | - Vasisht Tadigotla
- Life Technologies, Foster City, California, United States of America
| | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | | | | | - Stanley F. Nelson
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Tomas Marques-Bonet
- ICREA at Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
- Centro Nacional de Analisis Genomico (CNAG/PCB), Baldiri Reixach 4–8, Barcelona, Spain
| | - Elaine A. Ostrander
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Robert K. Wayne
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - John Novembre
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, United States of America
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25
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The cytochrome b5 reductase HPO-19 is required for biosynthesis of polyunsaturated fatty acids in Caenorhabditis elegans. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:310-9. [PMID: 26806391 DOI: 10.1016/j.bbalip.2016.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/13/2015] [Accepted: 01/17/2016] [Indexed: 11/23/2022]
Abstract
Polyunsaturated fatty acids (PUFAs) are fatty acids with backbones containing more than one double bond, which are introduced by a series of desaturases that insert double bonds at specific carbon atoms in the fatty acid chain. It has been established that desaturases need flavoprotein-NADH-dependent cytochrome b5 reductase (simplified as cytochrome b5 reductase) and cytochrome b5 to pass through electrons for activation. However, it has remained unclear how this multi-enzyme system works for distinct desaturases. The model organism Caenorhabditis elegans contains seven desaturases (FAT-1, -2, -3, -4, -5, -6, -7) for the biosynthesis of PUFAS, providing an excellent model in which to characterize different desaturation reactions. Here, we show that RNAi inactivation of predicted cytochrome b5 reductases hpo-19 and T05H4.4 led to increased levels of C18:1n-9 but decreased levels of PUFAs, small lipid droplets, decreased fat accumulation, reduced brood size and impaired development. Dietary supplementation with different fatty acids showed that HPO-19 and T05H4.4 likely affect the activity of FAT-1, FAT-2, FAT-3, and FAT-4 desaturases, suggesting that these four desaturases use the same cytochrome b5 reductase to function. Collectively, these findings indicate that cytochrome b5 reductase HPO-19/T05H4.4 is required for desaturation to biosynthesize PUFAs in C. elegans.
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Darabi M, Guillas-Baudouin I, Le Goff W, Chapman MJ, Kontush A. Therapeutic applications of reconstituted HDL: When structure meets function. Pharmacol Ther 2015; 157:28-42. [PMID: 26546991 DOI: 10.1016/j.pharmthera.2015.10.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Reconstituted forms of HDL (rHDL) are under development for infusion as a therapeutic approach to attenuate atherosclerotic vascular disease and to reduce cardiovascular risk following acute coronary syndrome and ischemic stroke. Currently available rHDL formulations developed for clinical use contain apolipoprotein A-I (apoA-I) and one of the major lipid components of HDL, either phosphatidylcholine or sphingomyelin. Recent data have established that quantitatively minor molecular constituents of HDL particles can strongly influence their anti-atherogenic functionality. Novel rHDL formulations displaying enhanced biological activities, including cellular cholesterol efflux, may therefore offer promising prospects for the development of HDL-based, anti-atherosclerotic therapies. Indeed, recent structural and functional data identify phosphatidylserine as a bioactive component of HDL; the content of phosphatidylserine in HDL particles displays positive correlations with all metrics of their functionality. This review summarizes current knowledge of structure-function relationships in rHDL formulations, with a focus on phosphatidylserine and other negatively-charged phospholipids. Mechanisms potentially underlying the atheroprotective role of these lipids are discussed and their potential for the development of HDL-based therapies highlighted.
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Affiliation(s)
- Maryam Darabi
- UMR INSERM-UPMC 1166 ICAN, Pavillon Benjamin Delessert, Hôpital de la Pitié, 83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France.
| | - Isabelle Guillas-Baudouin
- UMR INSERM-UPMC 1166 ICAN, Pavillon Benjamin Delessert, Hôpital de la Pitié, 83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France.
| | - Wilfried Le Goff
- UMR INSERM-UPMC 1166 ICAN, Pavillon Benjamin Delessert, Hôpital de la Pitié, 83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France.
| | - M John Chapman
- UMR INSERM-UPMC 1166 ICAN, Pavillon Benjamin Delessert, Hôpital de la Pitié, 83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France.
| | - Anatol Kontush
- UMR INSERM-UPMC 1166 ICAN, Pavillon Benjamin Delessert, Hôpital de la Pitié, 83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France.
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27
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Computational investigation of molecular mechanism and neuropathological implications in Huntington disease. Mol Cell Biochem 2015; 409:1-11. [DOI: 10.1007/s11010-015-2462-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 05/23/2015] [Indexed: 12/31/2022]
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Wille M, Schümann A, Wree A, Kreutzer M, Glocker MO, Mutzbauer G, Schmitt O. The Proteome Profiles of the Cerebellum of Juvenile, Adult and Aged Rats--An Ontogenetic Study. Int J Mol Sci 2015; 16:21454-85. [PMID: 26370973 PMCID: PMC4613263 DOI: 10.3390/ijms160921454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/04/2015] [Accepted: 08/25/2015] [Indexed: 11/16/2022] Open
Abstract
In this study, we searched for proteins that change their expression in the cerebellum (Ce) of rats during ontogenesis. This study focuses on the question of whether specific proteins exist which are differentially expressed with regard to postnatal stages of development. A better characterization of the microenvironment and its development may result from these study findings. A differential two-dimensional polyacrylamide gel electrophoresis (2DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of the samples revealed that the number of proteins of the functional classes differed depending on the developmental stages. Especially members of the functional classes of biosynthesis, regulatory proteins, chaperones and structural proteins show the highest differential expression within the analyzed stages of development. Therefore, members of these functional protein groups seem to be involved in the development and differentiation of the Ce within the analyzed development stages. In this study, changes in the expression of proteins in the Ce at different postnatal developmental stages (postnatal days (P) 7, 90, and 637) could be observed. At the same time, an identification of proteins which are involved in cell migration and differentiation was possible. Especially proteins involved in processes of the biosynthesis and regulation, the dynamic organization of the cytoskeleton as well as chaperones showed a high amount of differentially expressed proteins between the analyzed dates.
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Affiliation(s)
- Michael Wille
- Department of Anatomy, Gertrudenstr. 9, 18055 Rostock, Germany.
| | - Antje Schümann
- Department of Anatomy, Gertrudenstr. 9, 18055 Rostock, Germany.
| | - Andreas Wree
- Department of Anatomy, Gertrudenstr. 9, 18055 Rostock, Germany.
| | - Michael Kreutzer
- Proteome Center Rostock, Schillingallee 69, 18055 Rostock, Germany.
| | | | - Grit Mutzbauer
- Department of Pathology, Josef-Schneider-Str. 2, 97080 Würzburg, Germany.
| | - Oliver Schmitt
- Department of Anatomy, Gertrudenstr. 9, 18055 Rostock, Germany.
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Xie S, Naslavsky N, Caplan S. Diacylglycerol kinases in membrane trafficking. CELLULAR LOGISTICS 2015; 5:e1078431. [PMID: 27057419 DOI: 10.1080/21592799.2015.1078431] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 10/23/2022]
Abstract
Diacylglycerol kinases (DGKs) belong to a family of cytosolic kinases that regulate the phosphorylation of diacylglycerol (DAG), converting it into phosphatidic acid (PA). There are 10 known mammalian DGK isoforms, each with a different tissue distribution and substrate specificity. These differences allow regulation of cellular responses by fine-tuning the delicate balance of cellular DAG and PA. DGK isoforms are best characterized as mediators of signal transduction and immune function. However, since recent studies reveal that DAG and PA are also involved in the regulation of endocytic trafficking, it is therefore anticipated that DGKs also plays an important role in membrane trafficking. In this review, we summarize the literature discussing the role of DGK isoforms at different stages of endocytic trafficking, including endocytosis, exocytosis, endocytic recycling, and transport from/to the Golgi apparatus. Overall, these studies contribute to our understanding of the involvement of PA and DAG in endocytic trafficking, an area of research that is drawing increasing attention in recent years.
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Affiliation(s)
- Shuwei Xie
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center; University of Nebraska Medical Center ; Omaha, NE USA
| | - Naava Naslavsky
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center; University of Nebraska Medical Center ; Omaha, NE USA
| | - Steve Caplan
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center; University of Nebraska Medical Center ; Omaha, NE USA
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Hansen SB. Lipid agonism: The PIP2 paradigm of ligand-gated ion channels. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1851:620-8. [PMID: 25633344 PMCID: PMC4540326 DOI: 10.1016/j.bbalip.2015.01.011] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 01/05/2015] [Accepted: 01/17/2015] [Indexed: 01/08/2023]
Abstract
The past decade, membrane signaling lipids emerged as major regulators of ion channel function. However, the molecular nature of lipid binding to ion channels remained poorly described due to a lack of structural information and assays to quantify and measure lipid binding in a membrane. How does a lipid-ligand bind to a membrane protein in the plasma membrane, and what does it mean for a lipid to activate or regulate an ion channel? How does lipid binding compare to activation by soluble neurotransmitter? And how does the cell control lipid agonism? This review focuses on lipids and their interactions with membrane proteins, in particular, ion channels. I discuss the intersection of membrane lipid biology and ion channel biophysics. A picture emerges of membrane lipids as bona fide agonists of ligand-gated ion channels. These freely diffusing signals reside in the plasma membrane, bind to the transmembrane domain of protein, and cause a conformational change that allosterically gates an ion channel. The system employs a catalog of diverse signaling lipids ultimately controlled by lipid enzymes and raft localization. I draw upon pharmacology, recent protein structure, and electrophysiological data to understand lipid regulation and define inward rectifying potassium channels (Kir) as a new class of PIP2 lipid-gated ion channels.
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Affiliation(s)
- Scott B Hansen
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter FL 33458, USA.
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Petoukhov MV, Weissenhorn W, Svergun DI. Endophilin-A1 BAR domain interaction with arachidonyl CoA. Front Mol Biosci 2014; 1:20. [PMID: 25988161 PMCID: PMC4428356 DOI: 10.3389/fmolb.2014.00020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/08/2014] [Indexed: 11/13/2022] Open
Abstract
Endophilin-A1 belongs to the family of BAR domain containing proteins that catalyze membrane remodeling processes via sensing, inducing and stabilizing membrane curvature. We show that the BAR domain of endophilin-A1 binds arachidonic acid and molds its coenzyme A (CoA) activated form, arachidonyl-CoA into a defined structure. We studied low resolution structures of endophilin-A1-BAR and its complex with arachidonyl-CoA in solution using synchrotron small-angle X-ray scattering (SAXS). The free endophilin-A1-BAR domain is shown to be dimeric at lower concentrations but builds tetramers and higher order complexes with increasing concentrations. Extensive titration SAXS studies revealed that the BAR domain produces a homogenous complex with the lipid micelles. The structural model of the complexes revealed two arachidonyl-CoA micelles bound to the distal arms of an endophilin-A1-BAR dimer. Intriguingly, the radius of the bound micelles significantly decreases compared to that of the free micelles, and this structural result may provide hints on the potential biological relevance of the endophilin-A1-BAR interaction with arachidonyl CoA.
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Affiliation(s)
- Maxim V. Petoukhov
- Hamburg Unit, European Molecular Biology Laboratory c/o DESYHamburg, Germany
| | - Winfried Weissenhorn
- Unit of Virus Host Cell Interactions, University Grenoble AlpesGrenoble, France
- Unit of Virus Host Cell Interactions, Centre National de la Recherche ScientifiqueGrenoble, France
| | - Dmitri I. Svergun
- Hamburg Unit, European Molecular Biology Laboratory c/o DESYHamburg, Germany
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32
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Morphology control of giant vesicles by composition of mixed amphiphilic random block copolymers of poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid). Colloid Polym Sci 2014. [DOI: 10.1007/s00396-014-3403-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Pienimaeki-Roemer A, Fischer A, Tafelmeier M, Orsó E, Konovalova T, Böttcher A, Liebisch G, Reidel A, Schmitz G. High-density lipoprotein 3 and apolipoprotein A-I alleviate platelet storage lesion and release of platelet extracellular vesicles. Transfusion 2014; 54:2301-14. [PMID: 24912423 DOI: 10.1111/trf.12640] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND Stored platelet (PLT) concentrates (PLCs) for transfusion develop a PLT storage lesion (PSL), decreasing PLT viability and function with profound lipidomic changes and PLT extracellular vesicle (PL-EV) release. High-density lipoprotein 3 (HDL3 ) improves PLT homeostasis through silencing effects on PLT activation in vivo. This prompted us to investigate HDL3 and apolipoprotein A-I (apoA-I) as PSL-antagonizing agents. STUDY DESIGN AND METHODS Healthy donor PLCs were split into low-volume standard PLC storage bags and incubated with native (n)HDL3 or apoA-I from plasma ethanol fractionation (precipitate IV) for 5 days under standard blood banking conditions. Flow cytometry, Born aggregometry, and lipid mass spectrometry were carried out to analyze PL-EV release, PLT aggregation, agonist-induced PLT surface marker expression, and PLT and plasma lipid compositions. RESULTS Compared to control, added nHDL3 and apoA-I significantly reduced PL-EV release by up to -62% during 5 days, correlating with the added apoA-I concentration. At the lipid level, nHDL3 and apoA-I antagonized PLT lipid loss (+12%) and decreased cholesteryl ester (CE)/free cholesterol (FC) ratios (-69%), whereas in plasma polyunsaturated/saturated CE ratios increased (+3%) and CE 16:0/20:4 ratios decreased (-5%). Administration of nHDL3 increased PLT bis(monoacylglycero)phosphate/phosphatidylglycerol (+102%) and phosphatidic acid/lysophosphatidic acid (+255%) ratios and improved thrombin receptor-activating peptide 6-induced PLT aggregation (+5%). CONCLUSION nHDL3 and apoA-I improve PLT membrane homeostasis and intracellular lipid processing and increase CE efflux, antagonizing PSL-related reduction in PLT viability and function and PL-EV release. We suggest uptake and catabolism of nHDL3 into the PLT open canalicular system. As supplement in PLCs, nHDL3 or apoA-I from Fraction IV of plasma ethanol fractionation have the potential to improve PLC quality to prolong storage.
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34
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McMahon D, Dinh A, Kurz D, Shah D, Han GS, Carman GM, Brasaemle DL. Comparative gene identification 58/α/β hydrolase domain 5 lacks lysophosphatidic acid acyltransferase activity. J Lipid Res 2014; 55:1750-61. [PMID: 24879803 DOI: 10.1194/jlr.m051151] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Indexed: 01/07/2023] Open
Abstract
Mutations in the gene encoding comparative gene identification 58 (CGI-58)/α/β hydrolase domain 5 (ABHD5) cause Chanarin-Dorfman syndrome, characterized by excessive triacylglycerol storage in cells and tissues. CGI-58 has been identified as a coactivator of adipose TG lipase (ATGL) and a lysophosphatidic acid acyltransferase (LPAAT). We developed a molecular model of CGI-58 structure and then mutated predicted active site residues and performed LPAAT activity assays of recombinant WT and mutated CGI-58. When mutations of predicted catalytic residues failed to reduce LPAAT activity, we determined that LPAAT activity was due to a bacterial contaminant of affinity purification procedures, plsC, the sole LPAAT in Escherichia coli Purification protocols were optimized to reduce plsC contamination, in turn reducing LPAAT activity. When CGI-58 was expressed in SM2-1(DE3) cells that lack plsC, lysates lacked LPAAT activity. Additionally, mouse CGI-58 expressed in bacteria as a glutathione-S-transferase fusion protein and human CGI-58 expressed in yeast lacked LPAAT activity. Previously reported lipid binding activity of CGI-58 was revisited using protein-lipid overlays. Recombinant CGI-58 failed to bind lysophosphatidic acid, but interestingly, bound phosphatidylinositol 3-phosphate [PI(3)P] and phosphatidylinositol 5-phosphate [PI(5)P]. Prebinding CGI-58 with PI(3)P or PI(5)P did not alter its coactivation of ATGL in vitro. In summary, purified recombinant CGI-58 that is functional as an ATGL coactivator lacks LPAAT activity.
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Affiliation(s)
- Derek McMahon
- Rutgers Center for Lipid Research and Department of Nutritional Sciences and Rutgers Center for Lipid Research and Department of Food Science
| | - Anna Dinh
- Rutgers Center for Lipid Research and Department of Nutritional Sciences and Rutgers Center for Lipid Research and Department of Food Science
| | - Daniel Kurz
- Rutgers Center for Lipid Research and Department of Nutritional Sciences and Rutgers Center for Lipid Research and Department of Food Science
| | - Dharika Shah
- Rutgers Center for Lipid Research and Department of Nutritional Sciences and Rutgers Center for Lipid Research and Department of Food Science
| | - Gil-Soo Han
- Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
| | - George M Carman
- Rutgers, The State University of New Jersey, New Brunswick, NJ 08901
| | - Dawn L Brasaemle
- Rutgers Center for Lipid Research and Department of Nutritional Sciences and Rutgers Center for Lipid Research and Department of Food Science
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35
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Chen Z, Chang K, Capraro BR, Zhu C, Hsu CJ, Baumgart T. Intradimer/Intermolecular interactions suggest autoinhibition mechanism in endophilin A1. J Am Chem Soc 2014; 136:4557-64. [PMID: 24568626 PMCID: PMC3985530 DOI: 10.1021/ja411607b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
![]()
Endophilin
A1 is a homodimeric membrane-binding endocytic accessory
protein with a high dimerization affinity. Its function has been hypothesized
to involve autoinhibition. However, the autoinhibition mechanism,
as well as the physicochemical basis for the high dimerization affinity
of endophilin in solution, have remained unclear. In this contribution,
we use a Förster resonance energy transfer (FRET) method to
investigate the homodimerization mechanism and intradimer molecular
interactions in endophilin. For the endophilin N-BAR domain (which
lacks the SH3 domain including a linker region of the full length
protein), we observe a large temperature dependence of the dimerization
affinity and dimer dissociation kinetics, implying large dimerization
enthalpy and dissociation activation enthalpy, respectively. Our evaluation
of the protein concentration dependence of dimer dissociation kinetics
implies that endophilin reversibly forms monomers via a dissociation/reassociation
mechanism. Furthermore, we use a kinetic method that allows us to
compare the dissociation kinetics of full-length endophilin to that
of truncated mutants. We find that mutants that lack either H0 helix
or SH3 domain show significantly faster dissociation kinetics relative
to full-length endophilin. This observation supports the presence
of an intradimer, intermonomer cross-interaction between H0 helix
and SH3 domain from different subunits within a homodimer. Because
the H0 helix is known to play a significant role in endophilin’s
membrane interactions, our measurements support a syngergistic model
where these interactions are inhibited in the absence of SH3 domain
binding ligands such as dynamin’s prolin rich domains, and
where the binding of these ligands may be suppressed for non-membrane-bound
endophilin.
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Affiliation(s)
- Zhiming Chen
- Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
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36
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HER. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Watanabe S, Rost BR, Camacho-Pérez M, Davis MW, Söhl-Kielczynski B, Rosenmund C, Jorgensen EM. Ultrafast endocytosis at mouse hippocampal synapses. Nature 2013; 504:242-247. [PMID: 24305055 PMCID: PMC3957339 DOI: 10.1038/nature12809] [Citation(s) in RCA: 378] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 11/01/2013] [Indexed: 01/21/2023]
Abstract
To sustain neurotransmission, synaptic vesicles and their associated proteins must be recycled locally at synapses. Synaptic vesicles are thought to be regenerated approximately 20 s after fusion by the assembly of clathrin scaffolds or in approximately 1 s by the reversal of fusion pores via 'kiss-and-run' endocytosis. Here we use optogenetics to stimulate cultured hippocampal neurons with a single stimulus, rapidly freeze them after fixed intervals and examine the ultrastructure using electron microscopy--'flash-and-freeze' electron microscopy. Docked vesicles fuse and collapse into the membrane within 30 ms of the stimulus. Compensatory endocytosis occurs within 50 to 100 ms at sites flanking the active zone. Invagination is blocked by inhibition of actin polymerization, and scission is blocked by inhibiting dynamin. Because intact synaptic vesicles are not recovered, this form of recycling is not compatible with kiss-and-run endocytosis; moreover, it is 200-fold faster than clathrin-mediated endocytosis. It is likely that 'ultrafast endocytosis' is specialized to restore the surface area of the membrane rapidly.
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Affiliation(s)
- Shigeki Watanabe
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah, U.S.A
| | - Benjamin R Rost
- Neuroscience Research Centre, Charité Universitätsmedizin, Berlin, Germany
| | | | - M Wayne Davis
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah, U.S.A
| | | | | | - Erik M Jorgensen
- Department of Biology and Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah, U.S.A
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Functional pathways altered after silencing Pnpla6 (the codifying gene of neuropathy target esterase) in mouse embryonic stem cells under differentiation. In Vitro Cell Dev Biol Anim 2013; 50:261-73. [PMID: 24142151 DOI: 10.1007/s11626-013-9691-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Accepted: 09/10/2013] [Indexed: 12/15/2022]
Abstract
Neuropathy target esterase (NTE) is involved in several disorders in adult organisms and embryos. A relationship between NTE and nervous system integrity and maintenance in adult systems has been suggested. NTE-related motor neuron disease is associated with the expression of a mutant form of NTE and the inhibition and further modification of NTE by organophosphorus compounds is the trigger of a delayed neurodegenerative neuropathy. Homozygotic NTE knockout mice embryos are not viable, while heterozygotic NTE knockout mice embryos yields mice with neurological disorders, which suggest that this protein plays a critical role in embryonic development. The present study used D3 mouse embryonic stem cells with the aim of gaining mechanistic insights on the role of Pnpla6 (NTE gene encoding) in the developmental process. D3 cells were silenced by lipofectamine transfection with a specific interference RNA for Pnpla6. Silencing Pnpla6 in D3 monolayer cultures reduced NTE enzymatic activity to 50% 20 h post-treatment, while the maximum loss of Pnpla6 expression reached 80% 48 h postsilencing. Pnpla6 was silenced in embryoid bodies and 545 genes were differentially expressed regarding the control 96 h after silencing, which revealed alterations in multiple genetic pathways, such as cell motion and cell migration, vesicle regulation, and cell adhesion. These findings also allow considering that these altered pathways would impair the formation of respiratory, neural, and vascular tubes causing the deficiencies observed in the in vivo development of nervous and vascular systems. Our findings, therefore, support the previous observations made in vivo concerning lack of viability of mice embryos not expressing NTE and help to understand the biology of several neurological and developmental disorders in which NTE is involved.
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Components of the CtBP1/BARS-dependent fission machinery. Histochem Cell Biol 2013; 140:407-21. [PMID: 23996193 DOI: 10.1007/s00418-013-1138-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2013] [Indexed: 01/12/2023]
Abstract
The brefeldin A ADP-ribosylated substrate, a member of the C-terminal-binding protein family that is referred to as CtBP1/BARS, is a dual-function protein that acts as a transcriptional co-repressor in the nucleus and as an inducer of membrane fission in the cytoplasm. In this review, we first discuss the mechanisms that enable CtBP1/BARS to shift between the nuclear transcriptional co-repressor and the cytosolic fission-inducing activities. Then, we focus on the role of CtBP1/BARS in membrane fission. CtBP1/BARS controls several fission events including macropinocytosis, fluid-phase endocytosis, COPI-coated vesicle formation, basolaterally directed post-Golgi carrier formation, and Golgi partitioning in mitosis. We report on recent advances in our understanding of the CtBP1/BARS membrane fission machineries that operate at the trans-side and at the cis-side of the Golgi complex. Specifically, we discuss how these machineries are assembled and regulated, and how they operate in the formation of the basolaterally directed post-Golgi carriers.
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40
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Autoinhibition of endophilin in solution via interdomain interactions. Biophys J 2013; 104:396-403. [PMID: 23442861 DOI: 10.1016/j.bpj.2012.12.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 12/04/2012] [Accepted: 12/05/2012] [Indexed: 11/22/2022] Open
Abstract
Endophilin is a key protein involved in clathrin-mediated endocytosis. Previous computational and experimental work suggested that the N-terminal helix is embedded into the membrane to induce curvature; however, the role of the SH3 domain remains controversial. To address this issue, we performed computer simulations of the endophilin dimer in solution to understand the interaction between the N-BAR and SH3 domains and its effect on biological function. We predict that the helix binds to the SH3 domain through hydrophobic and salt-bridge interactions. This protects the hydrophobic residues on both domains and keeps the SH3 domain near the end of the N-BAR domain, in agreement with previous experimental results. The complex has a binding strength similar to a few hydrogen bonds (13.0 ± 0.6 kcal/mol), and the SH3 domain stabilizes the structure of the N-terminal helix in solution. Electrostatic calculations show a large region of strongly positive electrostatic potential near the N-terminal that can orient the helix toward the membrane and likely embed the helix into the membrane surface. This predicted mechanism suggests that endophilin can select for both curvature and electrostatic potential when interacting with membranes, highlighting the importance of the SH3 domain in regulating the function of endophilin.
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41
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The role of extracellular vesicles in phenotypic cancer transformation. Radiol Oncol 2013; 47:197-205. [PMID: 24133383 PMCID: PMC3794874 DOI: 10.2478/raon-2013-0037] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 05/02/2013] [Indexed: 12/14/2022] Open
Abstract
Background Cancer has traditionally been considered as a disease resulting from gene mutations. New findings in biology are challenging gene-centered explanations of cancer progression and redirecting them to the non-genetic origins of tumorigenicity. It has become clear that intercellular communication plays a crucial role in cancer progression. Among the most intriguing ways of intercellular communication is that via extracellular vesicles (EVs). EVs are membrane structures released from various types of cells. After separation from the mother membrane, EVs become mobile and may travel from the extracellular space to blood and other body fluids. Conclusions Recently it has been shown that tumour cells are particularly prone to vesiculation and that tumour-derived EVs can carry proteins, lipids and nucleic acids causative of cancer progression. The uptake of tumour-derived EVs by noncancerous cells can change their normal phenotype to cancerous. The suppression of vesiculation could slow down tumour growth and the spread of metastases. The purpose of this review is to highlight examples of EV-mediated cancer phenotypic transformation in the light of possible therapeutic applications.
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Otera H, Ishihara N, Mihara K. New insights into the function and regulation of mitochondrial fission. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1256-68. [PMID: 23434681 DOI: 10.1016/j.bbamcr.2013.02.002] [Citation(s) in RCA: 343] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 02/01/2013] [Accepted: 02/03/2013] [Indexed: 11/18/2022]
Abstract
Mitochondrial morphology changes dynamically by coordinated fusion and fission and cytoskeleton-based transport. Cycles of outer and inner membrane fusion and fission are required for the exchange of damaged mitochondrial genome DNA, proteins, and lipids with those of healthy mitochondria to maintain robust mitochondrial structure and function. These dynamics are crucial for cellular life and death, because they are essential for cellular development and homeostasis, as well as apoptosis. Disruption of these functions leads to cellular dysfunction, resulting in neurologic disorders and metabolic diseases. The cytoplasmic dynamin-related GTPase Drp1 plays a key role in mitochondrial fission, while Mfn1, Mfn2 and Opa1 are involved in fusion reaction. Here, we review current knowledge regarding the regulation and physiologic relevance of Drp1-dependent mitochondrial fission: the initial recruitment and assembly of Drp1 on the mitochondrial fission foci, regulation of Drp1 activity by post-translational modifications, and the role of mitochondrial fission in cell pathophysiology.
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Affiliation(s)
- Hidenori Otera
- Department of Molecular Biology, Kyushu University, Fukuoka, Japan
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Lemnitzer F, Raschbichler V, Kolodziejczak D, Israel L, Imhof A, Bailer SM, Koszinowski U, Ruzsics Z. Mouse cytomegalovirus egress protein pM50 interacts with cellular endophilin-A2. Cell Microbiol 2012. [PMID: 23189961 DOI: 10.1111/cmi.12080] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The herpesvirus replication cycle comprises maturation processes in the nucleus and cytoplasm of the infected cells. After their nuclear assembly viral capsids translocate via primary envelopment towards the cytoplasm. This event is mediated by the nuclear envelopment complex, which is composed by two conserved viral proteins belonging to the UL34 and UL31 protein families. Here, we generated recombinant viruses, which express affinity-tagged pM50 and/or pM53, the pUL34 and pUL31 homologues of the murine cytomegalovirus. We extracted pM50- and pM53-associated protein complexes from infected cells and analysed their composition after affinity purification by mass spectrometry. We observed reported interaction partners and identified new putative protein-protein interactions for both proteins. Endophilin-A2 was observed as the most prominent cellular partner of pM50. We found that endophilin-A2 binds to pM50 directly, and this interaction seems to be conserved in the pUL34 family.
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Affiliation(s)
- Frederic Lemnitzer
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität München, Pettenkoferstr. 9a, 80336 Munich, Germany
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Zhang J, Fan J, Tian Q, Song Z, Zhang JF, Chen Y. Characterization of two distinct modes of endophilin in clathrin-mediated endocytosis. Cell Signal 2012; 24:2043-50. [DOI: 10.1016/j.cellsig.2012.06.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 05/24/2012] [Accepted: 06/16/2012] [Indexed: 10/28/2022]
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Abstract
The striking morphology of the Golgi complex has fascinated cell biologists since its discovery over 100 years ago. Yet, despite intense efforts to understand how membrane flow relates to Golgi form and function, this organelle continues to baffle cell biologists and biochemists alike. Fundamental questions regarding Golgi function, while hotly debated, remain unresolved. Historically, Golgi function has been described from a protein-centric point of view, but we now appreciate that conceptual frameworks for how lipid metabolism is integrated with Golgi biogenesis and function are essential for a mechanistic understanding of this fascinating organelle. It is from a lipid-centric perspective that we discuss the larger question of Golgi dynamics and membrane trafficking. We review the growing body of evidence for how lipid metabolism is integrally written into the engineering of the Golgi system and highlight questions for future study.
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Affiliation(s)
- Vytas A Bankaitis
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
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Meyer SGE, Wendt AE, Scherer M, Liebisch G, Kerkweg U, Schmitz G, de Groot H. Myriocin, an inhibitor of serine palmitoyl transferase, impairs the uptake of transferrin and low-density lipoprotein in mammalian cells. Arch Biochem Biophys 2012; 526:60-8. [PMID: 22841978 DOI: 10.1016/j.abb.2012.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 07/09/2012] [Accepted: 07/10/2012] [Indexed: 11/29/2022]
Abstract
The role of sphingolipids in clathrin-mediated endocytosis is only poorly understood in mammalian cells. Thus the relationship between sphingolipid de novo synthesis and clathrin-mediated endocytosis of transferrin were studied in L929 fibroblasts and two other cell lines. Endocytosis was measured using live cell imaging with fluorescent transferrin or (125)I-transferrin. Lipids were primarily measured using electrospray ionization tandem mass spectrometry. At physiological temperature, transferrin uptake was significantly decreased by the inhibitor of serine palmitoyl transferase myriocin. Myriocin inhibited also the uptake of low-density lipoproteins. The endocytosis inhibition by myriocin could be released by the addition of sphingoid base and by the protein phosphorylation effectors phorbol-12-myristate, 13-acetate (PMA) and okadaic acid. Myriocin influenced not only sphingolipids but also the glycerophospholipid profile. The study of phosphatidylcholine species shows adaptations to more saturated, alkylated and longer fatty acid moieties. The reported results imply that in mammalian cells, at 37°C, sphingolipid de novo synthesis is required for clathrin-mediated endocytosis.
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Affiliation(s)
- Sybille G E Meyer
- Institut für Physiologische Chemie, Universitätsklinikum Essen, Essen, Germany.
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Kohli BM, Pflieger D, Mueller LN, Carbonetti G, Aebersold R, Nitsch RM, Konietzko U. Interactome of the amyloid precursor protein APP in brain reveals a protein network involved in synaptic vesicle turnover and a close association with Synaptotagmin-1. J Proteome Res 2012; 11:4075-90. [PMID: 22731840 DOI: 10.1021/pr300123g] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Knowledge of the protein networks interacting with the amyloid precursor protein (APP) in vivo can shed light on the physiological function of APP. To date, most proteins interacting with the APP intracellular domain (AICD) have been identified by Yeast Two Hybrid screens which only detect direct interaction partners. We used a proteomics-based approach by biochemically isolating tagged APP from the brains of transgenic mice and subjecting the affinity-purified complex to mass spectrometric (MS) analysis. Using two different quantitative MS approaches, we compared the protein composition of affinity-purified samples isolated from wild-type mice versus transgenic mice expressing tagged APP. This enabled us to assess truly enriched proteins in the transgenic sample and yielded an overlapping set of proteins containing the major proteins involved in synaptic vesicle endo- and exocytosis. Confocal microscopy analyses of cotransfected primary neurons showed colocalization of APP with synaptic vesicle proteins in vesicular structures throughout the neurites. We analyzed the interaction of APP with these proteins using pulldown experiments from transgenic mice or cotransfected cells followed by Western blotting. Synaptotagmin-1 (Stg1), a resident synaptic vesicle protein, was found to directly bind to APP. We fused Citrine and Cerulean to APP and the candidate proteins and measured fluorescence resonance energy transfer (FRET) in differentiated SH-SY5Y cells. Differentially tagged APPs showed clear sensitized FRET emission, in line with the described dimerization of APP. Among the candidate APP-interacting proteins, again only Stg1 was in close proximity to APP. Our results strongly argue for a function of APP in synaptic vesicle turnover in vivo. Thus, in addition to the APP cleavage product Aβ, which influences synaptic transmission at the postsynapse, APP interacts with the calcium sensor of synaptic vesicles and might thus play a role in the regulation of synaptic vesicle exocytosis.
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Affiliation(s)
- Bernhard M Kohli
- Institute of Psychiatry Research and Psychogeriatric Medicine, Faculty of Science, University Zurich, Switzerland
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Regulation of the Golgi complex by phospholipid remodeling enzymes. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1078-88. [PMID: 22562055 DOI: 10.1016/j.bbalip.2012.04.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 03/15/2012] [Accepted: 04/13/2012] [Indexed: 11/23/2022]
Abstract
The mammalian Golgi complex is a highly dynamic organelle consisting of stacks of flattened cisternae with associated coated vesicles and membrane tubules that contribute to cargo import and export, intra-cisternal trafficking, and overall Golgi architecture. At the morphological level, all of these structures are continuously remodeled to carry out these trafficking functions. Recent advances have shown that continual phospholipid remodeling by phospholipase A (PLA) and lysophospholipid acyltransferase (LPAT) enzymes, which deacylate and reacylate Golgi phospholipids, respectively, contributes to this morphological remodeling. Here we review the identification and characterization of four cytoplasmic PLA enzymes and one integral membrane LPAT that participate in the dynamic functional organization of the Golgi complex, and how some of these enzymes are integrated to determine the relative abundance of COPI vesicle and membrane tubule formation. This article is part of a Special Issue entitled Lipids and Vesicular Transport.
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Frisca F, Sabbadini RA, Goldshmit Y, Pébay A. Biological Effects of Lysophosphatidic Acid in the Nervous System. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY VOLUME 296 2012; 296:273-322. [DOI: 10.1016/b978-0-12-394307-1.00005-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Uncoupling the roles of synaptotagmin I during endo- and exocytosis of synaptic vesicles. Nat Neurosci 2011; 15:243-9. [PMID: 22197832 PMCID: PMC3435110 DOI: 10.1038/nn.3013] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 11/14/2011] [Indexed: 11/29/2022]
Abstract
Synaptotagmin I (syt1) is required for normal rates of synaptic vesicle endo- and exocytosis. However, whether the kinetic defects observed during endocytosis in syt1 knock-out neurons are secondary to defective exocytosis, or whether syt1 directly regulates the rate of vesicle retrieval, remains unresolved. In order to address this question, it is necessary to dissociate these two activities. Here, we have uncoupled the function of syt1 in exo- and endocytosis by re-targeting of the protein, or via mutagenesis of its tandem C2-domains; the impact of these manipulations on exo- and endocytosis were analyzed via electrophysiology, in conjunction with optical imaging of the vesicle cycle. These experiments uncovered a direct role for syt1 in endocytosis. Surprisingly, either C2-domain of syt1 - C2A or C2B - was able to function as Ca2+-sensor for endocytosis. Hence, syt1 functions as a dual Ca2+ sensor for both endo- and exocytosis, potentially coupling these two limbs of the vesicle cycle.
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