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Dickson EJ. Role of Lysosomal Cholesterol in Regulating PI(4,5)P 2-Dependent Ion Channel Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:193-215. [PMID: 36988882 DOI: 10.1007/978-3-031-21547-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Lysosomes are central regulators of cellular growth and signaling. Once considered the acidic garbage can of the cell, their ever-expanding repertoire of functions include the regulation of cell growth, gene regulation, metabolic signaling, cell migration, and cell death. In this chapter, we detail how another of the lysosome's crucial roles, cholesterol transport, plays a vital role in the control of ion channel function and neuronal excitability through its ability to influence the abundance of the plasma membrane signaling lipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). This chapter will introduce the biosynthetic pathways of cholesterol and PI(4,5)P2, discuss the molecular mechanisms through which each lipid distinctly regulates ion channels, and consider the interdependence of these lipids in the control of ion channel function.
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Affiliation(s)
- Eamonn J Dickson
- Department of Physiology and Membrane Biology, University of California, Davis, CA, USA.
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2
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Wallis TP, Venkatesh BG, Narayana VK, Kvaskoff D, Ho A, Sullivan RK, Windels F, Sah P, Meunier FA. Saturated free fatty acids and association with memory formation. Nat Commun 2021; 12:3443. [PMID: 34103527 PMCID: PMC8187648 DOI: 10.1038/s41467-021-23840-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/14/2021] [Indexed: 02/05/2023] Open
Abstract
Polyunsaturated free fatty acids (FFAs) such as arachidonic acid, released by phospholipase activity on membrane phospholipids, have long been considered beneficial for learning and memory and are known modulators of neurotransmission and synaptic plasticity. However, the precise nature of other FFA and phospholipid changes in specific areas of the brain during learning is unknown. Here, using a targeted lipidomics approach to characterise FFAs and phospholipids across the rat brain, we demonstrated that the highest concentrations of these analytes were found in areas of the brain classically involved in fear learning and memory, such as the amygdala. Auditory fear conditioning led to an increase in saturated (particularly myristic and palmitic acids) and to a lesser extent unsaturated FFAs (predominantly arachidonic acid) in the amygdala and prefrontal cortex. Both fear conditioning and changes in FFA required activation of NMDA receptors. These results suggest a role for saturated FFAs in memory acquisition.
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Affiliation(s)
- Tristan P Wallis
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Bharat G Venkatesh
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Vinod K Narayana
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
- Metabolomics Australia, Bio21 Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - David Kvaskoff
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
- Boehringer Ingelheim Pharma GmbH & Co. KG, Drug Discovery Sciences, Biberach an der Riß, Germany
| | - Alan Ho
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Robert K Sullivan
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - François Windels
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
- Joint Center for Neuroscience and Neural Engineering, and Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong Province, P. R. China
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.
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Abstract
Polyphosphoinositides (PPIn) are essential signaling phospholipids that make remarkable contributions to the identity of all cellular membranes and signaling cascades in mammalian cells. They exert regulatory control over membrane homeostasis via selective interactions with cellular proteins at the membrane–cytoplasm interface. This review article briefly summarizes our current understanding of the key roles that PPIn play in orchestrating and regulating crucial electrical and chemical signaling events in mammalian neurons and the significant neuro-pathophysiological conditions that arise following alterations in their metabolism.
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Affiliation(s)
- Eamonn James Dickson
- Department Physiology and Membrane Biology, University of California, Davis, CA, 95616, USA
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4
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A Closely Associated Phospholipase C Regulates Cation Channel Function through Phosphoinositide Hydrolysis. J Neurosci 2018; 38:7622-7634. [PMID: 30037836 DOI: 10.1523/jneurosci.0586-18.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/28/2018] [Accepted: 07/17/2018] [Indexed: 11/21/2022] Open
Abstract
In the hemaphroditic sea snail, Aplysia californica, reproduction is initiated when the bag cell neurons secrete egg-laying hormone during a protracted afterdischarge. A source of depolarization for the afterdischarge is a voltage-gated, nonselective cation channel, similar to transient receptor potential (TRP) channels. Once the afterdischarge is triggered, phospholipase C (PLC) is activated to hydrolyze phosphatidylinositol-4,5-bisphosphate (PIP2) into diacylglycerol (DAG) and inositol trisphosphate (IP3). We previously reported that a DAG analog, 1-oleoyl-2-acetyl-sn-glycerol (OAG), activates a prominent, inward whole-cell cationic current that is enhanced by IP3 To examine the underlying mechanism, we investigated the effect of exogenous OAG and IP3, as well as PLC activation, on cation channel activity and voltage dependence in excised, inside-out patches from cultured bag cell neurons. OAG transiently elevated channel open probability (PO) when applied to excised patches; however, coapplication of IP3 prolonged the OAG-induced response. In patches exposed to OAG and IP3, channel voltage dependence was left-shifted; this was also observed with OAG, but not to the same extent. Introducing the PLC activator, m-3M3FBS, to patches increased channel PO, suggesting PLC may be physically linked to the channels. Accordingly, blocking PLC with U-73122 ablated the m-3M3FBS-induced elevation in PO Treatment with m-3M3FBS left-shifted cation channel voltage dependence to a greater extent than exogenous OAG and IP3 Finally, OAG and IP3 potentiated the stimulatory effect of PKC, which is also associated with the channel. Thus, the PLC-PKC signaling system is physically localized such that PIP2 breakdown products liberated during the afterdischarge modulate the cation channel and temporally influence neuronal activity.SIGNIFICANCE STATEMENT Using excised patches from Aplysia bag cell neurons, we present the first evidence of a nonselective cation channel physically associating with phospholipase C (PLC) at the single-channel level. PLC-mediated breakdown of phospholipids generates diacylglycerol and inositol trisphosphate, which activate the cation channel. This is mimicked by exogenous lipids; furthermore, these second messengers left-shift channel voltage dependence and enhance the response of the channel to protein kinase C. PLC-mediated lipid signaling controls single-channel currents to ensure depolarization is maintained for an extended period of firing, termed the afterdischarge, when the bag cell neurons secrete egg-laying hormone to trigger reproduction.
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Garcia-Martinez V, Gimenez-Molina Y, Villanueva J, Darios FD, Davletov B, Gutiérrez LM. Emerging evidence for the modulation of exocytosis by signalling lipids. FEBS Lett 2018; 592:3493-3503. [PMID: 29962039 PMCID: PMC6282582 DOI: 10.1002/1873-3468.13178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/01/2018] [Accepted: 06/27/2018] [Indexed: 01/22/2023]
Abstract
Membrane fusion is a key event in exocytosis of neurotransmitters and hormones stored in intracellular vesicles. In this process, soluble N‐ethylmaleimide sensitive factor attachment protein receptor (SNARE) proteins are essential components of the exocytotic molecular machinery, while lipids have been seen traditionally as structural elements. However, the so‐called signalling lipids, such as sphingosine and arachidonic acid, interact with SNAREs and directly modulate the frequency and mode of fusion events. Interestingly, recent work has proved that the sphingosine analogue FTY‐720, used in the treatment of multiple sclerosis, mimics the effects of signalling lipids. In the present Review, we discuss recent investigations suggesting that endogenous signalling lipids and synthetic analogues can modulate important physiological aspects of secretion, such as quantal release, vesicle recruitment into active sites, vesicle transport and even organelle fusion in the cytosol. Therefore, these compounds are far from being merely structural components of cellular membranes.
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Affiliation(s)
- Virginia Garcia-Martinez
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - Yolanda Gimenez-Molina
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - José Villanueva
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - Frederic D Darios
- Inserm, U1127, CNRS, UMR 7225, Institut du Cerveau et de la Moelle épinière, ICM, Sorbonne Université, Paris, France
| | - Bazbek Davletov
- Department of Biomedical Sciences, University of Sheffield, UK
| | - Luis M Gutiérrez
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
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Roy U, Conklin L, Schiller J, Matysik J, Berry JP, Alia A. Metabolic profiling of zebrafish (Danio rerio) embryos by NMR spectroscopy reveals multifaceted toxicity of β-methylamino-L-alanine (BMAA). Sci Rep 2017; 7:17305. [PMID: 29230019 PMCID: PMC5725574 DOI: 10.1038/s41598-017-17409-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/21/2017] [Indexed: 11/09/2022] Open
Abstract
β-methylamino-L-alanine (BMAA) has been linked to several interrelated neurodegenerative diseases. Despite considerable research, specific contributions of BMAA toxicity to neurodegenerative diseases remain to be fully resolved. In the present study, we utilized state-of-the-art high-resolution magic-angle spinning nuclear magnetic resonance (HRMAS NMR), applied to intact zebrafish (Danio rerio) embryos, as a model of vertebrate development, to elucidate changes in metabolic profiles associated with BMAA exposure. Complemented by several alternative analytical approaches (i.e., in vivo visualization and in vitro assay), HRMAS NMR identified robust and dose-dependent effect of BMAA on several relevant metabolic pathways suggesting a multifaceted toxicity of BMAA including: (1) localized production of reactive oxygen species (ROS), in the developing brain, consistent with excitotoxicity; (2) decreased protective capacity against excitotoxicity and oxidative stress including reduced taurine and glutathione; (3) inhibition of several developmentally stereotypical energetic and metabolic transitions, i.e., metabolic reprogramming; and (4) inhibition of lipid biosynthetic pathways. Matrix-assisted laser desorption time-of-flight (MALDI-ToF) mass spectrometry further identified specific effects on phospholipids linked to both neural development and neurodegeneration. Taken together, a unified model of the neurodevelopmental toxicity of BMAA in the zebrafish embryo is presented in relation to the potential contribution of BMAA to neurodegenerative disease.
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Affiliation(s)
- Upasana Roy
- Institute for Medical Physics and Biophysics, University of Leipzig, D-04107, Leipzig, Germany.,Institute of Analytical Chemistry, University of Leipzig, D-04103, Leipzig, Germany
| | - Laura Conklin
- Department of Chemistry and Biochemistry, Florida International University, North Miami, FL, 33181, USA
| | - Jürgen Schiller
- Institute for Medical Physics and Biophysics, University of Leipzig, D-04107, Leipzig, Germany
| | - Jörg Matysik
- Institute of Analytical Chemistry, University of Leipzig, D-04103, Leipzig, Germany
| | - John P Berry
- Department of Chemistry and Biochemistry, Florida International University, North Miami, FL, 33181, USA.
| | - A Alia
- Institute for Medical Physics and Biophysics, University of Leipzig, D-04107, Leipzig, Germany. .,Leiden Institute of Chemistry, 2333, Leiden, The Netherlands.
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Gutiérrez LM, Villanueva J. The role of F-actin in the transport and secretion of chromaffin granules: an historic perspective. Pflugers Arch 2017; 470:181-186. [PMID: 28730385 PMCID: PMC5748413 DOI: 10.1007/s00424-017-2040-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 12/23/2022]
Abstract
Actin is one of the most ubiquitous protein playing fundamental roles in a variety of cellular processes. Since early in the 1980s, it was evident that filamentous actin (F-actin) formed a peripheral cortical barrier that prevented vesicles to access secretory sites in chromaffin cells in culture. Later, around 2000, it was described that the F-actin structure accomplishes a dual role serving both vesicle transport and retentive purposes and undergoing dynamic transient changes during cell stimulation. The complex role of the F-actin cytoskeleton in neuroendocrine secretion was further evidenced when it has been proved to participate in the scaffold structure holding together the secretory machinery at active sites and participate in the generation of mechanical forces that drive the opening of the fusion pore, during the first decade of the present century. The complex vision of the multiple roles of F-actin in secretion we have acquired to date comes largely from studies performed on traditional 2D cultures of primary cells; however, recent evidences suggest that these may not accurately mimic the 3D in vivo environment, and thus, more work is now needed on adrenomedullary cells kept in a more “native” configuration to fully understand the role of F-actin in regulating chromaffin granule transport and secretion under physiological conditions.
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Affiliation(s)
- Luis M Gutiérrez
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Alicante, Spain.
| | - José Villanueva
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Alicante, Spain
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8
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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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9
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Figueiredo T, Melo US, Pessoa ALS, Nobrega PR, Kitajima JP, Rusch H, Vaz F, Lucato LT, Zatz M, Kok F, Santos S. A homozygous loss-of-function mutation in inositol monophosphatase 1 (IMPA1) causes severe intellectual disability. Mol Psychiatry 2016; 21:1125-9. [PMID: 26416544 DOI: 10.1038/mp.2015.150] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 11/09/2022]
Abstract
The genetic basis of intellectual disability (ID) is extremely heterogeneous and relatively little is known about the role of autosomal recessive traits. In a field study performed in a highly inbred area of Northeastern Brazil, we identified and investigated a large consanguineous family with nine adult members affected by severe ID associated with disruptive behavior. The Genome-Wide Human SNP Array 6.0 microarray was used to determine regions of homozygosity by descent from three affected and one normal family member. Whole-exome sequencing (WES) was performed in one affected patient using the Nextera Rapid-Capture Exome kit and Illumina HiSeq2500 system to identify the causative mutation. Potentially deleterious variants detected in regions of homozygosity by descent and not present in either 59 723 unrelated individuals from the Exome Aggregation Consortium (Browser) or 1484 Brazilians were subject to further scrutiny and segregation analysis by Sanger sequencing. Homozygosity-by-descent analysis disclosed a 20.7-Mb candidate region at 8q12.3-q21.2 (lod score: 3.11). WES identified a homozygous deleterious variant in inositol monophosphatase 1 (IMPA1) (NM_005536), consisting of a 5-bp duplication (c.489_493dupGGGCT; chr8: 82,583,247; GRCh37/hg19) leading to a frameshift and a premature stop codon (p.Ser165Trpfs*10) that cosegregated with the disease in 26 genotyped family members. The IMPA1 gene product is responsible for the final step of biotransformation of inositol triphosphate and diacylglycerol, two second messengers. Despite its many physiological functions, no clinical phenotype has been assigned to this gene dysfunction to date. Additionally, IMPA1 is the main target of lithium, a drug that is at the forefront of treatment for bipolar disorder.
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Affiliation(s)
- T Figueiredo
- Northeast Biotechnology Network (RENORBIO), Federal University of Paraiba (UFPB), Joao Pessoa, Brazil.,Department of Biology, Paraiba State University (UEPB), Campina Grande, Brazil.,Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Biosciences Institute, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - U S Melo
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Biosciences Institute, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - A L S Pessoa
- Department of Neurology, School of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil.,School of Medicine, Fortaleza University (UNIFOR), Fortaleza, Brazil
| | - P R Nobrega
- Department of Neurology, School of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil
| | | | - H Rusch
- Laboratory of Genetic Metabolic Diseases, Department of Clinical Chemistry, University of Amsterdam, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - F Vaz
- Laboratory of Genetic Metabolic Diseases, Department of Clinical Chemistry, University of Amsterdam, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - L T Lucato
- Institute of Radiology, School of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - M Zatz
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Biosciences Institute, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - F Kok
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Biosciences Institute, University of Sao Paulo (USP), Sao Paulo, Brazil.,Department of Neurology, School of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil.,Mendelics Genomic Analysis, Sao Paulo, Brazil
| | - S Santos
- Northeast Biotechnology Network (RENORBIO), Federal University of Paraiba (UFPB), Joao Pessoa, Brazil.,Department of Biology, Paraiba State University (UEPB), Campina Grande, Brazil
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10
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Gross C. Defective phosphoinositide metabolism in autism. J Neurosci Res 2016; 95:1161-1173. [PMID: 27376697 DOI: 10.1002/jnr.23797] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/26/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022]
Abstract
Phosphoinositides are essential components of lipid membranes and crucial regulators of many cellular functions, including signal transduction, vesicle trafficking, membrane receptor localization and activity, and determination of membrane identity. These functions depend on the dynamic and highly regulated metabolism of phosphoinositides and require finely balanced activity of specific phosphoinositide kinases and phosphatases. There is increasing evidence from genetic and functional studies that these enzymes are often dysregulated or mutated in autism spectrum disorders; in particular, phosphoinositide 3-kinases and their regulatory subunits appear to be affected frequently. Examples of autism spectrum disorders with defective phosphoinositide metabolism are fragile X syndrome and autism disorders associated with mutations in the phosphoinositide 3-phosphatase tensin homolog deleted on chromosome 10 (PTEN), but recent genetic analyses also suggest that select nonsyndromic, idiopathic forms of autism may have altered activity of phosphoinositide kinases and phosphatases. Isoform-specific inhibitors for some of the phosphoinositide kinases have already been developed for cancer research and treatment, and a few are being evaluated for use in humans. Altogether, this offers exciting opportunities to explore altered phosphoinositide metabolism as a therapeutic target in individuals with certain forms of autism. This review summarizes genetic and functional studies identifying defects in phosphoinositide metabolism in autism and related disorders, describes published preclinical work targeting phosphoinositide 3-kinases in neurological diseases, and discusses the opportunities and challenges ahead to translate these findings from animal models and human cells into clinical application in humans. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio
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