1
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LeVine SM. Examining the Role of a Functional Deficiency of Iron in Lysosomal Storage Disorders with Translational Relevance to Alzheimer's Disease. Cells 2023; 12:2641. [PMID: 37998376 PMCID: PMC10670892 DOI: 10.3390/cells12222641] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/09/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023] Open
Abstract
The recently presented Azalea Hypothesis for Alzheimer's disease asserts that iron becomes sequestered, leading to a functional iron deficiency that contributes to neurodegeneration. Iron sequestration can occur by iron being bound to protein aggregates, such as amyloid β and tau, iron-rich structures not undergoing recycling (e.g., due to disrupted ferritinophagy and impaired mitophagy), and diminished delivery of iron from the lysosome to the cytosol. Reduced iron availability for biochemical reactions causes cells to respond to acquire additional iron, resulting in an elevation in the total iron level within affected brain regions. As the amount of unavailable iron increases, the level of available iron decreases until eventually it is unable to meet cellular demands, which leads to a functional iron deficiency. Normally, the lysosome plays an integral role in cellular iron homeostasis by facilitating both the delivery of iron to the cytosol (e.g., after endocytosis of the iron-transferrin-transferrin receptor complex) and the cellular recycling of iron. During a lysosomal storage disorder, an enzyme deficiency causes undigested substrates to accumulate, causing a sequelae of pathogenic events that may include cellular iron dyshomeostasis. Thus, a functional deficiency of iron may be a pathogenic mechanism occurring within several lysosomal storage diseases and Alzheimer's disease.
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Affiliation(s)
- Steven M LeVine
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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2
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Abstract
This chapter explores the existing structural and functional studies on the endo-lysosomal channel TRPML1 and its analogs TRPML2, TRPML3. These channels represent the mucolipin subfamily of the TRP channel superfamily comprising important roles in sensory physiology, ion homeostasis, and signal transduction. Since 2016, numerous structures have been determined for all three members using either cryo-EM or X-ray crystallography. These studies along with recent functional analysis have considerably strengthened our knowledge on TRPML channels and its related endo-lysosomal function. This chapter, together with relevant reports in other chapters from this handbook, provides an informative and detailed tool to study the endo-lysosomal cation channels.
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Affiliation(s)
- Michael Fine
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Xiaochun Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
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3
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Cantero MDR, Cantiello HF. Polycystin-2 (TRPP2): Ion channel properties and regulation. Gene 2022; 827:146313. [PMID: 35314260 DOI: 10.1016/j.gene.2022.146313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/19/2022] [Accepted: 02/08/2022] [Indexed: 12/01/2022]
Abstract
Polycystin-2 (TRPP2, PKD2, PC2) is the product of the PKD2 gene, whose mutations cause Autosomal Dominant Polycystic Kidney Disease (ADPKD). PC2 belongs to the superfamily of TRP (Transient Receptor Potential) proteins that generally function as Ca2+-permeable nonselective cation channels implicated in Ca2+ signaling. PC2 localizes to various cell domains with distinct functions that likely depend on interactions with specific channel partners. Functions include receptor-operated, nonselective cation channel activity in the plasma membrane, intracellular Ca2+ release channel activity in the endoplasmic reticulum (ER), and mechanosensitive channel activity in the primary cilium of renal epithelial cells. Here we summarize our current understanding of the properties of PC2 and how other transmembrane and cytosolic proteins modulate this activity, providing functional diversity and selective regulatory mechanisms to its role in the control of cellular Ca2+ homeostasis.
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Affiliation(s)
- María Del Rocío Cantero
- Laboratorio de Canales Iónicos, Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD, CONICET-UNSE), El Zanjón, Santiago del Estero 4206, Argentina.
| | - Horacio F Cantiello
- Laboratorio de Canales Iónicos, Instituto Multidisciplinario de Salud, Tecnología y Desarrollo (IMSaTeD, CONICET-UNSE), El Zanjón, Santiago del Estero 4206, Argentina
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4
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Lie PPY, Yoo L, Goulbourne CN, Berg MJ, Stavrides P, Huo C, Lee JH, Nixon RA. Axonal transport of late endosomes and amphisomes is selectively modulated by local Ca 2+ efflux and disrupted by PSEN1 loss of function. SCIENCE ADVANCES 2022; 8:eabj5716. [PMID: 35486730 PMCID: PMC9054012 DOI: 10.1126/sciadv.abj5716] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Dysfunction and mistrafficking of organelles in autophagy- and endosomal-lysosomal pathways are implicated in neurodegenerative diseases. Here, we reveal selective vulnerability of maturing degradative organelles (late endosomes/amphisomes) to disease-relevant local calcium dysregulation. These organelles undergo exclusive retrograde transport in axons, with occasional pauses triggered by regulated calcium efflux from agonist-evoked transient receptor potential cation channel mucolipin subfamily member 1 (TRPML1) channels-an effect greatly exaggerated by exogenous agonist mucolipin synthetic agonist 1 (ML-SA1). Deacidification of degradative organelles, as seen after Presenilin 1 (PSEN1) loss of function, induced pathological constitutive "inside-out" TRPML1 hyperactivation, slowing their transport comparably to ML-SA1 and causing accumulation in dystrophic axons. The mechanism involved calcium-mediated c-Jun N-terminal kinase (JNK) activation, which hyperphosphorylated dynein intermediate chain (DIC), reducing dynein activity. Blocking TRPML1 activation, JNK activity, or DIC1B serine-80 phosphorylation reversed transport deficits in PSEN1 knockout neurons. Our results, including features demonstrated in Alzheimer-mutant PSEN1 knockin mice, define a mechanism linking dysfunction and mistrafficking in lysosomal pathways to neuritic dystrophy under neurodegenerative conditions.
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Affiliation(s)
- Pearl P. Y. Lie
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA
| | - Lang Yoo
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA
| | - Chris N. Goulbourne
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Martin J. Berg
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Philip Stavrides
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Chunfeng Huo
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Ju-Hyun Lee
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA
- Department of Cell Biology, New York University Langone Medical Center, New York, NY 10016, USA
- NYU Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA
- Corresponding author.
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5
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Current Methods to Unravel the Functional Properties of Lysosomal Ion Channels and Transporters. Cells 2022; 11:cells11060921. [PMID: 35326372 PMCID: PMC8946281 DOI: 10.3390/cells11060921] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/04/2022] [Accepted: 03/05/2022] [Indexed: 02/07/2023] Open
Abstract
A distinct set of channels and transporters regulates the ion fluxes across the lysosomal membrane. Malfunctioning of these transport proteins and the resulting ionic imbalance is involved in various human diseases, such as lysosomal storage disorders, cancer, as well as metabolic and neurodegenerative diseases. As a consequence, these proteins have stimulated strong interest for their suitability as possible drug targets. A detailed functional characterization of many lysosomal channels and transporters is lacking, mainly due to technical difficulties in applying the standard patch-clamp technique to these small intracellular compartments. In this review, we focus on current methods used to unravel the functional properties of lysosomal ion channels and transporters, stressing their advantages and disadvantages and evaluating their fields of applicability.
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6
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Sun J, Liu Y, Hao X, Lin W, Su W, Chiang E, Baudry M, Bi X. LAMTOR1 inhibition of TRPML1‐dependent lysosomal calcium release regulates dendritic lysosome trafficking and hippocampal neuronal function. EMBO J 2022; 41:e108119. [PMID: 35099830 PMCID: PMC8886530 DOI: 10.15252/embj.2021108119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 12/12/2021] [Accepted: 12/21/2021] [Indexed: 02/05/2023] Open
Abstract
Lysosomes function not only as degradatory compartments but also as dynamic intracellular calcium ion stores. The transient receptor potential mucolipin 1 (TRPML1) channel mediates lysosomal Ca2+ release, thereby participating in multiple cellular functions. The pentameric Ragulator complex, which plays a critical role in the activation of mTORC1, is also involved in lysosomal trafficking and is anchored to lysosomes through its LAMTOR1 subunit. Here, we report that the Ragulator restricts lysosomal trafficking in dendrites of hippocampal neurons via LAMTOR1‐mediated tonic inhibition of TRPML1 activity, independently of mTORC1. LAMTOR1 directly interacts with TRPML1 through its N‐terminal domain. Eliminating this inhibition in hippocampal neurons by LAMTOR1 deletion or by disrupting LAMTOR1‐TRPML1 binding increases TRPML1‐mediated Ca2+ release and facilitates dendritic lysosomal trafficking powered by dynein. LAMTOR1 deletion in the hippocampal CA1 region of adult mice results in alterations in synaptic plasticity, and in impaired object‐recognition memory and contextual fear conditioning, due to TRPML1 activation. Mechanistically, changes in synaptic plasticity are associated with increased GluA1 dephosphorylation by calcineurin and lysosomal degradation. Thus, LAMTOR1‐mediated inhibition of TRPML1 is critical for regulating dendritic lysosomal motility, synaptic plasticity, and learning.
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Affiliation(s)
- Jiandong Sun
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona CA USA
| | - Yan Liu
- Graduate College of Biomedical Sciences Western University of Health Sciences Pomona CA USA
| | - Xiaoning Hao
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona CA USA
| | - Weiju Lin
- Graduate College of Biomedical Sciences Western University of Health Sciences Pomona CA USA
| | - Wenyue Su
- Graduate College of Biomedical Sciences Western University of Health Sciences Pomona CA USA
| | - Emerald Chiang
- Graduate College of Biomedical Sciences Western University of Health Sciences Pomona CA USA
| | - Michel Baudry
- Graduate College of Biomedical Sciences Western University of Health Sciences Pomona CA USA
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona CA USA
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7
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Bobkov D, Semenova S. Impact of lipid rafts on transient receptor potential channel activities. J Cell Physiol 2022; 237:2034-2044. [PMID: 35014032 DOI: 10.1002/jcp.30679] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/06/2021] [Accepted: 12/23/2021] [Indexed: 11/06/2022]
Abstract
Members of the transient receptor potential (TRP) superfamily are cation channels that are expressed in nearly every mammalian cell type and respond as cellular sensors to various environmental stimuli. Light, pressure, osmolarity, temperature, and other stimuli can induce TRP calcium conductivity and correspondingly trigger many signaling processes in cells. Disruption of TRP channel activity, as a rule, harms cellular function. Despite numerous studies, the mechanisms of TRP channel regulation are not yet sufficiently clear, in part, because TRP channels are regulated by a broad set of ligands having diverse physical and chemical features. It is now known that some TRP members are located in membrane microdomains termed lipid rafts. Moreover, interaction between specific raft-associated lipids with channels may be a key regulation mechanism. This review examines recent findings related to the roles of lipid rafts in regulation of TRP channel activity. The mechanistic events of channel interactions with the main lipid raft constituent, cholesterol, are being clarified. Better understanding of mechanisms behind such interactions would help establish the key elements of TRP channel regulation and hence allow control of cellular responses to environmental stimuli.
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Affiliation(s)
- Danila Bobkov
- Laboratory of Ionic Mechanisms of Cell Signaling, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| | - Svetlana Semenova
- Laboratory of Ionic Mechanisms of Cell Signaling, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
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8
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Davis LC, Morgan AJ, Galione A. Acidic Ca 2+ stores and immune-cell function. Cell Calcium 2021; 101:102516. [PMID: 34922066 DOI: 10.1016/j.ceca.2021.102516] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/03/2021] [Accepted: 12/04/2021] [Indexed: 12/11/2022]
Abstract
Acidic organelles act as intracellular Ca2+ stores; they actively sequester Ca2+ in their lumina and release it to the cytosol upon activation of endo-lysosomal Ca2+ channels. Recent data suggest important roles of endo-lysosomal Ca2+ channels, the Two-Pore Channels (TPCs) and the TRPML channels (mucolipins), in different aspects of immune-cell function, particularly impacting membrane trafficking, vesicle fusion/fission and secretion. Remarkably, different channels on the same acidic vesicles can couple to different downstream physiology. Endo-lysosomal Ca2+ stores can act under different modalities, be they acting alone (via local Ca2+ nanodomains around TPCs/TRPMLs) or in conjunction with the ER Ca2+ store (to either promote or suppress global ER Ca2+ release). These different modalities impinge upon functions as broad as phagocytosis, cell-killing, anaphylaxis, immune memory, thrombostasis, and chemotaxis.
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Affiliation(s)
- Lianne C Davis
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| | - Anthony J Morgan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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9
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Negri S, Faris P, Moccia F. Endolysosomal Ca 2+ signaling in cardiovascular health and disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 363:203-269. [PMID: 34392930 DOI: 10.1016/bs.ircmb.2021.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An increase in intracellular Ca2+ concentration ([Ca2+]i) regulates a plethora of functions in the cardiovascular (CV) system, including contraction in cardiomyocytes and vascular smooth muscle cells (VSMCs), and angiogenesis in vascular endothelial cells and endothelial colony forming cells. The sarco/endoplasmic reticulum (SR/ER) represents the largest endogenous Ca2+ store, which releases Ca2+ through ryanodine receptors (RyRs) and/or inositol-1,4,5-trisphosphate receptors (InsP3Rs) upon extracellular stimulation. The acidic vesicles of the endolysosomal (EL) compartment represent an additional endogenous Ca2+ store, which is targeted by several second messengers, including nicotinic acid adenine dinucleotide phosphate (NAADP) and phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2], and may release intraluminal Ca2+ through multiple Ca2+ permeable channels, including two-pore channels 1 and 2 (TPC1-2) and Transient Receptor Potential Mucolipin 1 (TRPML1). Herein, we discuss the emerging, pathophysiological role of EL Ca2+ signaling in the CV system. We describe the role of cardiac TPCs in β-adrenoceptor stimulation, arrhythmia, hypertrophy, and ischemia-reperfusion injury. We then illustrate the role of EL Ca2+ signaling in VSMCs, where TPCs promote vasoconstriction and contribute to pulmonary artery hypertension and atherosclerosis, whereas TRPML1 sustains vasodilation and is also involved in atherosclerosis. Subsequently, we describe the mechanisms whereby endothelial TPCs promote vasodilation, contribute to neurovascular coupling in the brain and stimulate angiogenesis and vasculogenesis. Finally, we discuss about the possibility to target TPCs, which are likely to mediate CV cell infection by the Severe Acute Respiratory Disease-Coronavirus-2, with Food and Drug Administration-approved drugs to alleviate the detrimental effects of Coronavirus Disease-19 on the CV system.
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Affiliation(s)
- Sharon Negri
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Pawan Faris
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Francesco Moccia
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
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10
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Santoni G, Amantini C, Nabissi M, Maggi F, Arcella A, Marinelli O, Eleuteri AM, Santoni M, Morelli MB. Knock-Down of Mucolipin 1 Channel Promotes Tumor Progression and Invasion in Human Glioblastoma Cell Lines. Front Oncol 2021; 11:578928. [PMID: 33954107 PMCID: PMC8092188 DOI: 10.3389/fonc.2021.578928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 02/12/2021] [Indexed: 12/21/2022] Open
Abstract
Among cancers that affect the central nervous system, glioblastoma is the most common. Given the negative prognostic significance of transient receptor potential mucolipin 1 (TRPML1) channel reduction in patients with glioblastoma, as discussed in previous publications, the aim of the current study was to investigate the biological advantage of TRPML1 loss for glioma cells. Human glioblastoma primary cancer cells (FSL and FCL) and glioblastoma cell lines (T98 and U251) were used for that purpose. TRPML1 silencing in T98 cells induces defective autophagy, nitric oxide (NO) production, and cathepsin B-dependent apoptosis in the first 48 h and then apoptotic-resistant cells proliferate with a high growth rate with respect to control cells. In U251 cells, knock-down of TRPML1 stimulates NO generation and protein oxidation, arrests cell cycle at G2/M phase, and induces autophagy leading to cathepsin B-dependent senescence. Finally, in both cell lines, the long-term effects of TRPML1 silencing promote survival and invasion capacity with respect to control cells. Silencing of TRPML1 also affects the phenotype of glioblastoma primary cells. FSL cells show increased proliferation ability, while FCL cells enter into senescence associated with an increased invasion ability. In conclusion, although the molecular heterogeneity among different glioblastoma cell lines mirrors the intercellular heterogeneity in cancer cells, our data support TRPML1 downregulation as a negative prognostic factor in glioblastoma.
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Affiliation(s)
- Giorgio Santoni
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Consuelo Amantini
- Immunopathology Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Massimo Nabissi
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Federica Maggi
- Department of Molecular Medicine, Sapienza University, Rome, Italy
| | - Antonietta Arcella
- Neuropathology Laboratory, Istituto di Ricovero e Cura a Carattere Scientifico Neuromed, Pozzilli, Italy
| | - Oliviero Marinelli
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Anna Maria Eleuteri
- Clinical Biochemistry Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Matteo Santoni
- Medical Oncology Unit, Hospital of Macerata, Macerata, Italy
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11
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Huizing M, Gahl WA. Inherited disorders of lysosomal membrane transporters. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2020; 1862:183336. [PMID: 32389669 PMCID: PMC7508925 DOI: 10.1016/j.bbamem.2020.183336] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/01/2020] [Accepted: 04/28/2020] [Indexed: 02/07/2023]
Abstract
Disorders caused by defects in lysosomal membrane transporters form a distinct subgroup of lysosomal storage disorders (LSDs). To date, defects in only 10 lysosomal membrane transporters have been associated with inherited disorders. The clinical presentations of these diseases resemble the phenotypes of other LSDs; they are heterogeneous and often present in children with neurodegenerative manifestations. However, for pathomechanistic and therapeutic studies, lysosomal membrane transport defects should be distinguished from LSDs caused by defective hydrolytic enzymes. The involved proteins differ in function, localization, and lysosomal targeting, and the diseases themselves differ in their stored material and therapeutic approaches. We provide an overview of the small group of disorders of lysosomal membrane transporters, emphasizing discovery, pathomechanism, clinical features, diagnostic methods and therapeutic aspects. We discuss common aspects of lysosomal membrane transporter defects that can provide the basis for preclinical research into these disorders.
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Affiliation(s)
- Marjan Huizing
- Human Biochemical Genetics Section, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - William A Gahl
- Human Biochemical Genetics Section, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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12
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Leal-Gutiérrez JD, Elzo MA, Carr C, Mateescu RG. RNA-seq analysis identifies cytoskeletal structural genes and pathways for meat quality in beef. PLoS One 2020; 15:e0240895. [PMID: 33175867 PMCID: PMC7657496 DOI: 10.1371/journal.pone.0240895] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 10/05/2020] [Indexed: 01/03/2023] Open
Abstract
RNA sequencing (RNA-seq) has allowed for transcriptional profiling of biological systems through the identification of differentially expressed (DE) genes and pathways. A total of 80 steers with extreme phenotypes were selected from the University of Florida multibreed Angus-Brahman herd. The average slaughter age was 12.91±8.69 months. Tenderness, juiciness and connective tissue assessed by sensory panel, along with marbling, Warner-Bratzler Shear Force (WBSF) and cooking loss, were measured in longissimus dorsi muscle. Total RNA was extracted from muscle and one RNA-seq library per sample was constructed, multiplexed, and sequenced based on protocols by Illumina HiSeq-3000 platform to generate 2×101 bp paired-end reads. The overall read mapping rate using the Btau_4.6.1 reference genome was 63%. A total of 8,799 genes were analyzed using two different methodologies, an expression association and a DE analysis. A gene and exon expression association analysis was carried out using a meat quality index on all 80 samples as a continuous response variable. The expression of 208 genes and 3,280 exons from 1,565 genes was associated with the meat quality index (p-value ≤ 0.05). A gene and isoform DE evaluation was performed analyzing two groups with extreme WBSF, tenderness and marbling. A total of 676 (adjusted p-value≤0.05), 70 (adjusted p-value≤0.1) and 198 (adjusted p-value≤0.1) genes were DE for WBSF, tenderness and marbling, respectively. A total of 106 isoforms from 98 genes for WBSF, 13 isoforms from 13 genes for tenderness and 43 isoforms from 42 genes for marbling (FDR≤0.1) were DE. Cytoskeletal and transmembrane anchoring genes and pathways were identified in the expression association, DE and the gene enrichment analyses; these proteins can have a direct effect on meat quality. Cytoskeletal proteins and transmembrane anchoring molecules can influence meat quality by allowing cytoskeletal interaction with myocyte and organelle membranes, contributing to cytoskeletal structure and architecture maintenance postmortem.
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Affiliation(s)
- Joel D. Leal-Gutiérrez
- Department of Animal Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Mauricio A. Elzo
- Department of Animal Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Chad Carr
- Department of Animal Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Raluca G. Mateescu
- Department of Animal Sciences, University of Florida, Gainesville, Florida, United States of America
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13
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Mitochondria-lysosome contacts regulate mitochondrial Ca 2+ dynamics via lysosomal TRPML1. Proc Natl Acad Sci U S A 2020; 117:19266-19275. [PMID: 32703809 DOI: 10.1073/pnas.2003236117] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mitochondria and lysosomes are critical for cellular homeostasis, and dysfunction of both organelles has been implicated in numerous diseases. Recently, interorganelle contacts between mitochondria and lysosomes were identified and found to regulate mitochondrial dynamics. However, whether mitochondria-lysosome contacts serve additional functions by facilitating the direct transfer of metabolites or ions between the two organelles has not been elucidated. Here, using high spatial and temporal resolution live-cell microscopy, we identified a role for mitochondria-lysosome contacts in regulating mitochondrial calcium dynamics through the lysosomal calcium efflux channel, transient receptor potential mucolipin 1 (TRPML1). Lysosomal calcium release by TRPML1 promotes calcium transfer to mitochondria, which was mediated by tethering of mitochondria-lysosome contact sites. Moreover, mitochondrial calcium uptake at mitochondria-lysosome contact sites was modulated by the outer and inner mitochondrial membrane channels, voltage-dependent anion channel 1 and the mitochondrial calcium uniporter, respectively. Since loss of TRPML1 function results in the lysosomal storage disorder mucolipidosis type IV (MLIV), we examined MLIV patient fibroblasts and found both altered mitochondria-lysosome contact dynamics and defective contact-dependent mitochondrial calcium uptake. Thus, our work highlights mitochondria-lysosome contacts as key contributors to interorganelle calcium dynamics and their potential role in the pathophysiology of disorders characterized by dysfunctional mitochondria or lysosomes.
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14
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Lloyd-Evans E, Waller-Evans H. Lysosomal Ca 2+ Homeostasis and Signaling in Health and Disease. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035311. [PMID: 31653642 DOI: 10.1101/cshperspect.a035311] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Calcium (Ca2+) signaling is an essential process in all cells that is maintained by a plethora of channels, pumps, transporters, receptors, and intracellular Ca2+ sequestering stores. Changes in cytosolic Ca2+ concentration govern processes as far reaching as fertilization, cell growth, and motility through to cell death. In recent years, lysosomes have emerged as a major intracellular Ca2+ storage organelle with an increasing involvement in triggering or regulating cellular functions such as endocytosis, autophagy, and Ca2+ release from the endoplasmic reticulum. This review will summarize recent work in the area of lysosomal Ca2+ signaling and homeostasis, including newly identified functions, and the involvement of lysosome-derived Ca2+ signals in human disease. In addition, we explore recent controversies in the techniques used for measurement of lysosomal Ca2+ content.
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Affiliation(s)
- Emyr Lloyd-Evans
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, United Kingdom
| | - Helen Waller-Evans
- Medicines Discovery Institute, Cardiff University, Cardiff CF10 3AT, United Kingdom
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15
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Santoni G, Morelli MB, Amantini C, Nabissi M, Santoni M, Santoni A. Involvement of the TRPML Mucolipin Channels in Viral Infections and Anti-viral Innate Immune Responses. Front Immunol 2020; 11:739. [PMID: 32425938 PMCID: PMC7212413 DOI: 10.3389/fimmu.2020.00739] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/31/2020] [Indexed: 12/23/2022] Open
Abstract
The TRPML channels (TRPML1, TRPML2, and TRPML3), belonging to the mucolipin TRP subfamily, primary localize to a population of membrane-bonded vesicles along the endocytosis, and exocytosis pathways. Human viruses enter host cells by plasma membrane penetration or by receptor-mediated endocytosis. TRPML2 enhances the infectivity of a number of enveloped viruses by promoting virus vesicular trafficking and escape from endosomal compartment. TRPML2 expression is stimulated by interferon and by several toll like receptor (TLR) activators, suggesting a possible role in the activation of the innate immune response. Noteworthy, TRPML1 plays a major role in single strand RNA/DNA trafficking into lysosomes and the lack of TRPML1 impairs the TLR-7 and TLR-9 ligand transportation to lysosomes resulting in decreased dendritic cell maturation/activation and migration to the lymph nodes. TRPML channels are also expressed by natural killer (NK) cells, a subset of innate lymphocytes with an essential role during viral infections; recent findings have indicated a role of TRPML1-mediated modulation of secretory lysosomes in NK cells education. Moreover, as also NK cells express TLR recognizing viral pattern, an increased TLR-mediated activation of cytokine production can be envisaged, suggesting a dual role in the NK cell-mediated antiviral responses. Overall, TRPML channels might play a double-edged sword in resistance to viral infections: on one side they can promote virus cellular entry and infectivity; on the other side, by regulating TLR responses in the various immune cells, they contribute to enhance antiviral innate and possibly adaptive immune responses.
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Affiliation(s)
- Giorgio Santoni
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | | | - Consuelo Amantini
- Immunopathology Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Massimo Nabissi
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Matteo Santoni
- Medical Oncology Unit, Hospital of Macerata, Macerata, Italy
| | - Angela Santoni
- Department of Molecular Medicine, Sapienza University, Rome, Italy.,IRCCS Neuromed, Pozzilli, Italy
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16
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Santoni G, Santoni M, Maggi F, Marinelli O, Morelli MB. Emerging Role of Mucolipins TRPML Channels in Cancer. Front Oncol 2020; 10:659. [PMID: 32411610 PMCID: PMC7198773 DOI: 10.3389/fonc.2020.00659] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/08/2020] [Indexed: 12/26/2022] Open
Affiliation(s)
- Giorgio Santoni
- Section of Immunopathology, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Matteo Santoni
- Medical Oncology Unit, Hospital of Macerata, Macerata, Italy
| | - Federica Maggi
- Section of Immunopathology, School of Pharmacy, University of Camerino, Camerino, Italy.,Department of Molecular Medicine, University of Rome Sapienza, Rome, Italy
| | - Oliviero Marinelli
- Section of Immunopathology, School of Pharmacy, University of Camerino, Camerino, Italy.,School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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17
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Hayashi T, Hosono K, Kubo A, Kurata K, Katagiri S, Mizobuchi K, Kurai M, Mamiya N, Kondo M, Tachibana T, Saitsu H, Ogata T, Nakano T, Hotta Y. Long-term observation of a Japanese mucolipidosis IV patient with a novel homozygous p.F313del variant of MCOLN1. Am J Med Genet A 2020; 182:1500-1505. [PMID: 32220057 DOI: 10.1002/ajmg.a.61575] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/05/2020] [Accepted: 03/13/2020] [Indexed: 11/11/2022]
Abstract
Mucolipidosis type IV (MLIV) is an autosomal recessively inherited lysosomal storage disorder characterized by progressive psychomotor delay and retinal degeneration that is associated with biallelic variants in the MCOLN1 gene. The gene, which is expressed in late endosomes and lysosomes of various tissue cells, encodes the transient receptor potential channel mucolipin 1 consisting of six transmembrane domains. Here, we described 14-year follow-up observation of a 4-year-old Japanese male MLIV patient with a novel homozygous in-frame deletion variant p.(F313del), which was identified by whole-exome sequencing analysis. Neurological examination revealed progressive psychomotor delay, and atrophy of the corpus callosum and cerebellum was observed on brain magnetic resonance images. Ophthalmologically, corneal clouding has remained unchanged during the follow-up period, whereas optic nerve pallor and retinal degenerative changes exhibited progressive disease courses. Light-adapted electroretinography was non-recordable. Transmission electron microscopy of granulocytes revealed characteristic concentric multiple lamellar structures and an electron-dense inclusion in lysosomes. The in-frame deletion variant was located within the second transmembrane domain, which is of putative functional importance for channel properties.
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Affiliation(s)
- Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Katsushika Medical Center, The Jikei University School of Medicine, Tokyo, Japan
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Akiko Kubo
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Kinan Hospital, Mie, Japan
| | - Kentaro Kurata
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Satoshi Katagiri
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kei Mizobuchi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | | | - Norihito Mamiya
- Department of Pediatrics, Kinan Hospital, Mie, Japan.,Department of Pediatrics, Mie University Graduate School of Medicine, Mie, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Mie, Japan
| | - Toshiaki Tachibana
- Core Research Facilities for Basic Science, The Jikei University School of Medicine, Tokyo, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Tsutomu Ogata
- Department of Pediatrics, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, Shizuoka, Japan
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18
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Santoni G, Maggi F, Amantini C, Marinelli O, Nabissi M, Morelli MB. Pathophysiological Role of Transient Receptor Potential Mucolipin Channel 1 in Calcium-Mediated Stress-Induced Neurodegenerative Diseases. Front Physiol 2020; 11:251. [PMID: 32265740 PMCID: PMC7105868 DOI: 10.3389/fphys.2020.00251] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 03/05/2020] [Indexed: 12/15/2022] Open
Abstract
Mucolipins (TRPML) are endosome/lysosome Ca2+ permeable channels belonging to the family of transient receptor potential channels. In mammals, there are three TRPML proteins, TRPML1, 2, and 3, encoded by MCOLN1-3 genes. Among these channels, TRPML1 is a reactive oxygen species sensor localized on the lysosomal membrane that is able to control intracellular oxidative stress due to the activation of the autophagic process. Moreover, genetic or pharmacological inhibition of the TRPML1 channel stimulates oxidative stress signaling pathways. Experimental data suggest that elevated levels of reactive species play a role in several neurological disorders. There is a need to gain better understanding of the molecular mechanisms behind these neurodegenerative diseases, considering that the main sources of free radicals are mitochondria, that mitochondria/endoplasmic reticulum and lysosomes are coupled, and that growing evidence links neurodegenerative diseases to the gain or loss of function of proteins related to lysosome homeostasis. This review examines the significant roles played by the TRPML1 channel in the alterations of calcium signaling responsible for stress-mediated neurodegenerative disorders and its potential as a new therapeutic target for ameliorating neurodegeneration in our ever-aging population.
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Affiliation(s)
- Giorgio Santoni
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Federica Maggi
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy.,Department of Molecular Medicine, Sapienza University, Rome, Italy
| | - Consuelo Amantini
- Immunopathology Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Oliviero Marinelli
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy.,Immunopathology Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Massimo Nabissi
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Maria Beatrice Morelli
- Immunopathology Laboratory, School of Pharmacy, University of Camerino, Camerino, Italy.,Immunopathology Laboratory, School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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19
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Yamaguchi N, Ban K, Suzuki A, Nakamura Y, Kato K, Muramatsu H, Okuno Y, Hattori A, Kaname T, Takahashi Y, Saitoh S. Novel compound heterozygous MCOLN1 mutations identified in a Japanese girl with severe developmental delay and thin corpus callosum. Brain Dev 2020; 42:298-301. [PMID: 31899079 DOI: 10.1016/j.braindev.2019.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 12/05/2019] [Accepted: 12/08/2019] [Indexed: 11/19/2022]
Abstract
Mucolipidosis type IV (MLIV) is a rare lysosomal storage disorder causing severe psychomotor developmental delay and progressive visual impairment. MLIV is an autosomal recessive disease caused by mutations in MCOLN1, which encodes for mucolipin-1. Here, we report a case of a 4-year-old Japanese girl with severe intellectual disability and motor deficits. Brain magnetic resonance imaging showed signal abnormalities in the white matter and thinning of the corpus callosum. Whole-exome sequencing was performed on the proband and her parents, and novel compound heterozygous mutations at c.936_938del (p.Phe313del) and c.1503dupC (p.Ile502Hisfs*106) in MCOLN1 (NM_020533.2) were identified in the proband. Additional biochemical examinations revealed elevated serum gastrin level and iron deficiency anemia, leading to the diagnosis of MLIV. More reports of such pathogenic mutations are expected to broaden the understanding of the channel function of mucolipin-1 and genotype-phenotype correlations.
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Affiliation(s)
- Naoya Yamaguchi
- Department of Neonatology and Pediatrics, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Kyoko Ban
- Department of Pediatrics, Yokkaichi Municipal Hospital, Yokkaichi, Japan
| | - Atsushi Suzuki
- Department of Neonatology and Pediatrics, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yuji Nakamura
- Department of Neonatology and Pediatrics, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Kohji Kato
- Department of Neonatology and Pediatrics, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan; Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hideki Muramatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yusuke Okuno
- Medical Genomics Center, Nagoya University Hospital, Nagoya, Japan
| | - Ayako Hattori
- Department of Neonatology and Pediatrics, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Tadashi Kaname
- Department of Genome Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Yoshiyuki Takahashi
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Saitoh
- Department of Neonatology and Pediatrics, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
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20
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Endolysosomal Ca 2+ Signalling and Cancer Hallmarks: Two-Pore Channels on the Move, TRPML1 Lags Behind! Cancers (Basel) 2018; 11:cancers11010027. [PMID: 30591696 PMCID: PMC6356888 DOI: 10.3390/cancers11010027] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 12/22/2022] Open
Abstract
The acidic vesicles of the endolysosomal (EL) system are emerging as an intracellular Ca2+ store implicated in the regulation of multiple cellular functions. The EL Ca2+ store releases Ca2+ through a variety of Ca2+-permeable channels, including Transient Receptor Potential (TRP) Mucolipin 1-3 (TRPML1-3) and two-pore channels 1-2 (TPC1-2), whereas EL Ca2+ refilling is sustained by the proton gradient across the EL membrane and/or by the endoplasmic reticulum (ER). EL Ca2+ signals may be either spatially restricted to control vesicle trafficking, autophagy and membrane repair or may be amplified into a global Ca2+ signal through the Ca2+-dependent recruitment of ER-embedded channels. Emerging evidence suggested that nicotinic acid adenine dinucleotide phosphate (NAADP)-gated TPCs sustain multiple cancer hallmarks, such as migration, invasiveness and angiogenesis. Herein, we first survey the EL Ca2+ refilling and release mechanisms and then focus on the oncogenic role of EL Ca2+ signaling. While the evidence in favor of TRPML1 involvement in neoplastic transformation is yet to be clearly provided, TPCs are emerging as an alternative target for anticancer therapies.
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21
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Lie PPY, Nixon RA. Lysosome trafficking and signaling in health and neurodegenerative diseases. Neurobiol Dis 2018; 122:94-105. [PMID: 29859318 DOI: 10.1016/j.nbd.2018.05.015] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/27/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022] Open
Abstract
Lysosomes, single-membrane organelles defined by a uniquely strong acidic lumenal pH and high content of acid hydrolases, are the shared degradative compartments of the endocytic and autophagic pathways. These pathways, and especially lysosomes, are points of particular vulnerability in many neurodegenerative diseases. Beyond the role of lysosomes in substrate degradation, new findings have ascribed to lysosomes the leading role in sensing and responding to cellular nutrients, growth factors and cellular stress. This review aims to integrate recent concepts of basic lysosome biology and pathobiology as a basis for understanding neurodegenerative disease pathogenesis. Here, we discuss the newly recognized signaling functions of lysosomes and specific aspects of lysosome biology in neurons while re-visiting the classical defining criteria for lysosomes and the importance of preserving strict definitions. Our discussion emphasizes dynein-mediated axonal transport of maturing degradative organelles, with further consideration of their roles in synaptic function. We finally examine how distinctive underlying disturbances of lysosomes in various neurodegenerative diseases result in unique patterns of auto/endolysosomal mistrafficking. The rapidly emerging understanding of lysosomal trafficking and disruptions in lysosome signaling is providing valuable clues to new targets for disease-modifying therapies.
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Affiliation(s)
- Pearl P Y Lie
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA.
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA; Department of Cell Biology, New York University Langone Medical Center, New York, NY 10016, USA; NYU Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA
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22
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Zhou X, Li M, Su D, Jia Q, Li H, Li X, Yang J. Cryo-EM structures of the human endolysosomal TRPML3 channel in three distinct states. Nat Struct Mol Biol 2017; 24:1146-1154. [PMID: 29106414 PMCID: PMC5747366 DOI: 10.1038/nsmb.3502] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 10/10/2017] [Indexed: 12/23/2022]
Abstract
TRPML3 channels are mainly localized to endolysosomes and play a critical role in the endocytic pathway. Their dysfunction causes deafness and pigmentation defects in mice. TRPML3 activity is inhibited by low endolysosomal pH. Here we present cryo-electron microscopy (cryo-EM) structures of human TRPML3 in the closed, agonist-activated, and low-pH-inhibited states, with resolutions of 4.06, 3.62, and 4.65 Å, respectively. The agonist ML-SA1 lodges between S5 and S6 and opens an S6 gate. A polycystin-mucolipin domain (PMD) forms a luminal cap. S1 extends into this cap, forming a 'gating rod' that connects directly to a luminal pore loop, which undergoes dramatic conformational changes in response to low pH. S2 extends intracellularly and interacts with several intracellular regions to form a 'gating knob'. These unique structural features, combined with the results of electrophysiological studies, indicate a new mechanism by which luminal pH and other physiological modulators such as PIP2 regulate TRPML3 by changing S1 and S2 conformations.
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Affiliation(s)
- Xiaoyuan Zhou
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Minghui Li
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Deyuan Su
- Department of Biological Sciences, Columbia University, New York, NY, USA
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, and Ion Channel Research and Drug Development Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Qi Jia
- Department of Orthopedic Oncology, Shanghai Changzheng Hospital, The Second Military Medical University, Shanghai 200003, China
| | - Huan Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, and Ion Channel Research and Drug Development Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, China
| | - Xueming Li
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jian Yang
- Department of Biological Sciences, Columbia University, New York, NY, USA
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, and Ion Channel Research and Drug Development Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
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23
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Solomon M, Muro S. Lysosomal enzyme replacement therapies: Historical development, clinical outcomes, and future perspectives. Adv Drug Deliv Rev 2017; 118:109-134. [PMID: 28502768 PMCID: PMC5828774 DOI: 10.1016/j.addr.2017.05.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/26/2017] [Accepted: 05/08/2017] [Indexed: 01/06/2023]
Abstract
Lysosomes and lysosomal enzymes play a central role in numerous cellular processes, including cellular nutrition, recycling, signaling, defense, and cell death. Genetic deficiencies of lysosomal components, most commonly enzymes, are known as "lysosomal storage disorders" or "lysosomal diseases" (LDs) and lead to lysosomal dysfunction. LDs broadly affect peripheral organs and the central nervous system (CNS), debilitating patients and frequently causing fatality. Among other approaches, enzyme replacement therapy (ERT) has advanced to the clinic and represents a beneficial strategy for 8 out of the 50-60 known LDs. However, despite its value, current ERT suffers from several shortcomings, including various side effects, development of "resistance", and suboptimal delivery throughout the body, particularly to the CNS, lowering the therapeutic outcome and precluding the use of this strategy for a majority of LDs. This review offers an overview of the biomedical causes of LDs, their socio-medical relevance, treatment modalities and caveats, experimental alternatives, and future treatment perspectives.
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Affiliation(s)
- Melani Solomon
- Institute for Bioscience and Biotechnology Research, University Maryland, College Park, MD 20742, USA
| | - Silvia Muro
- Institute for Bioscience and Biotechnology Research, University Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University Maryland, College Park, MD 20742, USA.
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24
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Di Paola S, Scotto-Rosato A, Medina DL. TRPML1: The Ca (2+)retaker of the lysosome. Cell Calcium 2017; 69:112-121. [PMID: 28689729 DOI: 10.1016/j.ceca.2017.06.006] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/16/2017] [Accepted: 06/16/2017] [Indexed: 12/27/2022]
Abstract
Efficient functioning of lysosome is necessary to ensure the correct performance of a variety of intracellular processes such as degradation of cargoes coming from the endocytic and autophagic pathways, recycling of organelles, and signaling mechanisms involved in cellular adaptation to nutrient availability. Mutations in lysosomal genes lead to more than 50 lysosomal storage disorders (LSDs). Among them, mutations in the gene encoding TRPML1 (MCOLN1) cause Mucolipidosis type IV (MLIV), a recessive LSD characterized by neurodegeneration, psychomotor retardation, ophthalmologic defects and achlorhydria. At the cellular level, MLIV patient fibroblasts show enlargement and engulfment of the late endo-lysosomal compartment, autophagy impairment, and accumulation of lipids and glycosaminoglycans. TRPML1 is the most extensively studied member of a small family of genes that also includes TRPML2 and TRPML3, and it has been found to participate in vesicular trafficking, lipid and ion homeostasis, and autophagy. In this review we will provide an update on the latest and more novel findings related to the functions of TRPMLs, with particular focus on the emerging role of TRPML1 and lysosomal calcium signaling in autophagy. Moreover, we will also discuss new potential therapeutic approaches for MLIV and LSDs based on the modulation of TRPML1-mediated signaling.
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Affiliation(s)
- Simone Di Paola
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy
| | - Anna Scotto-Rosato
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy
| | - Diego Luis Medina
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078 Pozzuoli ,NA, Italy.
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25
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Methods for monitoring Ca 2+ and ion channels in the lysosome. Cell Calcium 2017; 64:20-28. [DOI: 10.1016/j.ceca.2016.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 12/07/2016] [Accepted: 12/07/2016] [Indexed: 12/22/2022]
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26
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Structural basis of dual Ca 2+/pH regulation of the endolysosomal TRPML1 channel. Nat Struct Mol Biol 2017; 24:205-213. [PMID: 28112729 PMCID: PMC5336481 DOI: 10.1038/nsmb.3362] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/12/2016] [Indexed: 12/01/2022]
Abstract
Organellar ion channels are essential for cell physiology. Their activities are often regulated by Ca2+ and H+, which are concentrated in many organelles. Here we report a novel structural element critical for Ca2+/pH dual regulation of TRPML1, a Ca2+ release channel crucial for endolysosomal functions. TRPML1 mutations cause mucolipidosis type IV (MLIV), a severe lysosomal storage disorder characterized by neurodegeneration, mental retardation and blindness. We obtained high-resolution crystal structures of a 213-amino acid luminal domain of human TRPML1 that harbors three missense MLIV-causing mutations. This domain forms a tetramer with a highly electronegative central pore formed by a novel luminal pore-loop. Cysteine crosslinking and cryo-EM confirm this structure in the full-length channel. Structure-function studies demonstrate that Ca2+ and H+ interact with the luminal pore to exert physiologically important regulation. The MLIV-causing mutations disrupt the luminal domain structure and cause TRPML1 mislocalization. Our study provides a structural underpinning for TRPML1's regulation, assembly and pathogenesis.
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27
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Lloyd-Evans E, Haslett LJ. The lysosomal storage disease continuum with ageing-related neurodegenerative disease. Ageing Res Rev 2016; 32:104-121. [PMID: 27516378 DOI: 10.1016/j.arr.2016.07.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/19/2016] [Accepted: 07/29/2016] [Indexed: 12/11/2022]
Abstract
Lysosomal storage diseases and diseases of ageing share many features both at the physiological level and with respect to the mechanisms that underlie disease pathogenesis. Although the exact pathophysiology is not exactly the same, it is astounding how many similar pathways are altered in all of these diseases. The aim of this review is to provide a summary of the shared disease mechanisms, outlining the similarities and differences and how genetics, insight into rare diseases and functional research has changed our perspective on the causes underlying common diseases of ageing. The lysosome should no longer be considered as just the stomach of the cell or as a suicide bag, it has an emerging role in cellular signalling, nutrient sensing and recycling. The lysosome is of fundamental importance in the pathophysiology of diseases of ageing and by comparing against the LSDs we not only identify common pathways but also therapeutic targets so that ultimately more effective treatments can be developed for all neurodegenerative diseases.
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Abstract
Lysosomes have emerged in the last decade as an immensely important intracellular site of Ca2+ storage and signalling. More recently there has been an increase in the number of new ion channels found to be functional on lysosomes and the potential roles that these signalling pathways might play in fundamental cellular processes are being uncovered. Defects in lysosomal function have been shown to result in changes in lysosomal Ca2+ homeostasis and ultimately can result in cell death. Several neurodegenerative diseases, from rare lysosomal storage diseases through to more common diseases of ageing, have recently been identified as having alterations in lysosomal Ca2+ homeostasis that may play an important role in neuronal excitotoxicity and ultimately cell death. This review will critically summarise these recent findings.
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Affiliation(s)
- Emyr Lloyd-Evans
- School of Biosciences, Sir Martin Evans Building, Cardiff University, Museum Avenue, Cardiff, CF10 3AX
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29
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Abstract
TRPML1 is a ubiquitously expressed cation channel found on lysosomes and late endosomes. Mutations in TRPML1 cause mucolipidosis type IV and it has been implicated in Alzheimer's disease and HIV. However, the mechanisms by which TRPML1 activity is regulated are not well understood. This review summarizes the current understanding of TRPML1 activation and regulation.
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30
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Lambie EJ, Bruce RD, Zielich J, Yuen SN. Novel Alleles of gon-2, a C. elegans Ortholog of Mammalian TRPM6 and TRPM7, Obtained by Genetic Reversion Screens. PLoS One 2015; 10:e0143445. [PMID: 26606136 PMCID: PMC4659536 DOI: 10.1371/journal.pone.0143445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 11/04/2015] [Indexed: 11/19/2022] Open
Abstract
TRP (Transient Receptor Potential) cation channels of the TRPM subfamily have been found to be critically important for the regulation of Mg2+ homeostasis in both protostomes (e.g., the nematode, C. elegans, and the insect, D. melanogaster) and deuterostomes (e.g., humans). Although significant progress has been made toward understanding how the activities of these channels are regulated, there are still major gaps in our understanding of the potential regulatory roles of extensive, evolutionarily conserved, regions of these proteins. The C. elegans genes, gon-2, gtl-1 and gtl-2, encode paralogous TRP cation channel proteins that are similar in sequence and function to human TRPM6 and TRPM7. We isolated fourteen revertants of the missense mutant, gon-2(q338), and these mutations affect nine different residues within GON-2. Since eight of the nine affected residues are situated within regions that have high similarity to human TRPM1,3,6 and 7, these mutations identify sections of these channels that are potentially critical for channel regulation. We also isolated a single mutant allele of gon-2 during a screen for revertants of the Mg2+-hypersensitive phenotype of gtl-2(-) mutants. This allele of gon-2 converts a serine to phenylalanine within the highly conserved TRP domain, and is antimorphic against both gon-2(+) and gtl-1(+). Interestingly, others have reported that mutation of the corresponding residue in TRPM7 to glutamate results in deregulated channel activity.
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Affiliation(s)
- Eric J. Lambie
- Department of Cell and Developmental Biology, Ludwig Maximilian University, Munich, Germany
- * E-mail:
| | - Robert D. Bruce
- Dept. of Internal Medicine, Madigan Army Medical Center, Fort Lewis-McChord, Washington, United States of America
| | - Jeffrey Zielich
- Department of Cell and Developmental Biology, Ludwig Maximilian University, Munich, Germany
| | - Sonia N. Yuen
- Department of Otolaryngology, Boston Children’s Hospital, Boston, Massachusetts, United States of America
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ESCRT-Dependent Cell Death in a Caenorhabditis elegans Model of the Lysosomal Storage Disorder Mucolipidosis Type IV. Genetics 2015; 202:619-38. [PMID: 26596346 DOI: 10.1534/genetics.115.182485] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/14/2015] [Indexed: 01/08/2023] Open
Abstract
Mutations in MCOLN1, which encodes the cation channel protein TRPML1, result in the neurodegenerative lysosomal storage disorder Mucolipidosis type IV. Mucolipidosis type IV patients show lysosomal dysfunction in many tissues and neuronal cell death. The ortholog of TRPML1 in Caenorhabditis elegans is CUP-5; loss of CUP-5 results in lysosomal dysfunction in many tissues and death of developing intestinal cells that results in embryonic lethality. We previously showed that a null mutation in the ATP-Binding Cassette transporter MRP-4 rescues the lysosomal defect and embryonic lethality of cup-5(null) worms. Here we show that reducing levels of the Endosomal Sorting Complex Required for Transport (ESCRT)-associated proteins DID-2, USP-50, and ALX-1/EGO-2, which mediate the final de-ubiquitination step of integral membrane proteins being sequestered into late endosomes, also almost fully suppresses cup-5(null) mutant lysosomal defects and embryonic lethality. Indeed, we show that MRP-4 protein is hypo-ubiquitinated in the absence of CUP-5 and that reducing levels of ESCRT-associated proteins suppresses this hypo-ubiquitination. Thus, increased ESCRT-associated de-ubiquitinating activity mediates the lysosomal defects and corresponding cell death phenotypes in the absence of CUP-5.
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Lee JH, McBrayer MK, Wolfe DM, Haslett LJ, Kumar A, Sato Y, Lie PPY, Mohan P, Coffey EE, Kompella U, Mitchell CH, Lloyd-Evans E, Nixon RA. Presenilin 1 Maintains Lysosomal Ca(2+) Homeostasis via TRPML1 by Regulating vATPase-Mediated Lysosome Acidification. Cell Rep 2015; 12:1430-44. [PMID: 26299959 DOI: 10.1016/j.celrep.2015.07.050] [Citation(s) in RCA: 250] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 04/22/2015] [Accepted: 07/24/2015] [Indexed: 12/28/2022] Open
Abstract
Presenilin 1 (PS1) deletion or Alzheimer's disease (AD)-linked mutations disrupt lysosomal acidification and proteolysis, which inhibits autophagy. Here, we establish that this phenotype stems from impaired glycosylation and instability of vATPase V0a1 subunit, causing deficient lysosomal vATPase assembly and function. We further demonstrate that elevated lysosomal pH in Presenilin 1 knockout (PS1KO) cells induces abnormal Ca(2+) efflux from lysosomes mediated by TRPML1 and elevates cytosolic Ca(2+). In WT cells, blocking vATPase activity or knockdown of either PS1 or the V0a1 subunit of vATPase reproduces all of these abnormalities. Normalizing lysosomal pH in PS1KO cells using acidic nanoparticles restores normal lysosomal proteolysis, autophagy, and Ca(2+) homeostasis, but correcting lysosomal Ca(2+) deficits alone neither re-acidifies lysosomes nor reverses proteolytic and autophagic deficits. Our results indicate that vATPase deficiency in PS1 loss-of-function states causes lysosomal/autophagy deficits and contributes to abnormal cellular Ca(2+) homeostasis, thus linking two AD-related pathogenic processes through a common molecular mechanism.
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Affiliation(s)
- Ju-Hyun Lee
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA
| | - Mary Kate McBrayer
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Devin M Wolfe
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Luke J Haslett
- Division of Pathophysiology and Repair, Cardiff University, Cardiff CF10 3XQ, UK
| | - Asok Kumar
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Pathology, New York University, New York, NY 10016, USA
| | - Yutaka Sato
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Pearl P Y Lie
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Panaiyur Mohan
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA
| | - Erin E Coffey
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Uday Kompella
- Pharmaceutical Science and Ophthalmology, University of Colorado, Aurora, CO 80045, USA
| | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emyr Lloyd-Evans
- Division of Pathophysiology and Repair, Cardiff University, Cardiff CF10 3XQ, UK
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA; Department of Cell Biology, New York University, New York, NY 10016, USA.
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The role of TRPMLs in endolysosomal trafficking and function. Cell Calcium 2014; 58:48-56. [PMID: 25465891 DOI: 10.1016/j.ceca.2014.10.008] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 12/24/2022]
Abstract
Members of the Transient Receptor Potential-Mucolipin (TRPML) constitute a family of evolutionarily conserved cation channels that function predominantly in endolysosomal vesicles. Whereas loss-of-function mutations in human TRPML1 were first identified as being causative for the lysosomal storage disease, Mucolipidosis type IV, most mammals also express two other TRPML isoforms called TRPML2 and TRPML3. All three mammalian TRPMLs as well as TRPML related genes in other species including Caenorhabditis elegans and Drosophila exhibit overlapping functional and biophysical properties. The functions of TRPML proteins include roles in vesicular trafficking and biogenesis, maintenance of neuronal development, function, and viability, and regulation of intracellular and organellar ionic homeostasis. Biophysically, TRPML channels are non-selective cation channels exhibiting variable permeability to a host of cations including Na(+), Ca(2+), Fe(2+), and Zn(2+), and are activated by a phosphoinositide species, PI(3,5)P2, that is mostly found in endolysosomal membranes. Here, we review the functional and biophysical properties of these enigmatic cation channels, which represent the most ancient and archetypical TRP channels.
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Zemojtel T, Köhler S, Mackenroth L, Jäger M, Hecht J, Krawitz P, Graul-Neumann L, Doelken S, Ehmke N, Spielmann M, Oien NC, Schweiger MR, Krüger U, Frommer G, Fischer B, Kornak U, Flöttmann R, Ardeshirdavani A, Moreau Y, Lewis SE, Haendel M, Smedley D, Horn D, Mundlos S, Robinson PN. Effective diagnosis of genetic disease by computational phenotype analysis of the disease-associated genome. Sci Transl Med 2014; 6:252ra123. [PMID: 25186178 PMCID: PMC4512639 DOI: 10.1126/scitranslmed.3009262] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Less than half of patients with suspected genetic disease receive a molecular diagnosis. We have therefore integrated next-generation sequencing (NGS), bioinformatics, and clinical data into an effective diagnostic workflow. We used variants in the 2741 established Mendelian disease genes [the disease-associated genome (DAG)] to develop a targeted enrichment DAG panel (7.1 Mb), which achieves a coverage of 20-fold or better for 98% of bases. Furthermore, we established a computational method [Phenotypic Interpretation of eXomes (PhenIX)] that evaluated and ranked variants based on pathogenicity and semantic similarity of patients' phenotype described by Human Phenotype Ontology (HPO) terms to those of 3991 Mendelian diseases. In computer simulations, ranking genes based on the variant score put the true gene in first place less than 5% of the time; PhenIX placed the correct gene in first place more than 86% of the time. In a retrospective test of PhenIX on 52 patients with previously identified mutations and known diagnoses, the correct gene achieved a mean rank of 2.1. In a prospective study on 40 individuals without a diagnosis, PhenIX analysis enabled a diagnosis in 11 cases (28%, at a mean rank of 2.4). Thus, the NGS of the DAG followed by phenotype-driven bioinformatic analysis allows quick and effective differential diagnostics in medical genetics.
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Affiliation(s)
- Tomasz Zemojtel
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Poland. Labor Berlin-Charité Vivantes GmbH, Humangenetik, Föhrer Straße 15, 13353 Berlin, Germany
| | - Sebastian Köhler
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Luisa Mackenroth
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Marten Jäger
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Jochen Hecht
- Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany. Berlin-Brandenburg Center for Regenerative Therapies, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Peter Krawitz
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany
| | - Luitgard Graul-Neumann
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Sandra Doelken
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Nadja Ehmke
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Malte Spielmann
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany
| | - Nancy Christine Oien
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Michal R Schweiger
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany. Cologne Center for Genomics, University of Cologne, D-50931 Cologne, Germany
| | - Ulrike Krüger
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Götz Frommer
- Agilent Technologies, Hewlett-Packard-Straße 8, 76337 Waldbronn, Germany
| | - Björn Fischer
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany
| | - Uwe Kornak
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany
| | - Ricarda Flöttmann
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Amin Ardeshirdavani
- Department of Electrical Engineering, STADIUS Center for Dynamical Systems, Signal Processing and Data Analytics, KU Leuven, 3001 Leuven, Belgium
| | - Yves Moreau
- Department of Electrical Engineering, STADIUS Center for Dynamical Systems, Signal Processing and Data Analytics, KU Leuven, 3001 Leuven, Belgium
| | - Suzanna E Lewis
- Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Melissa Haendel
- University Library and Department of Medical Informatics and Clinical Epidemiology, Oregon Health & Sciences University, Portland, OR 97327, USA
| | - Damian Smedley
- Mouse Informatics Group, Wellcome Trust Sanger Institute, CB10 1SA Hinxton, UK
| | - Denise Horn
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Stefan Mundlos
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany. Berlin-Brandenburg Center for Regenerative Therapies, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany
| | - Peter N Robinson
- Institute for Medical Genetics and Human Genetics, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany. Berlin-Brandenburg Center for Regenerative Therapies, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany. Institute for Bioinformatics, Department of Mathematics and Computer Science, Freie Universität Berlin, Takustr. 9, 14195 Berlin, Germany.
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Kaneko Y, Szallasi A. Transient receptor potential (TRP) channels: a clinical perspective. Br J Pharmacol 2014; 171:2474-507. [PMID: 24102319 PMCID: PMC4008995 DOI: 10.1111/bph.12414] [Citation(s) in RCA: 284] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/28/2013] [Accepted: 08/31/2013] [Indexed: 12/14/2022] Open
Abstract
Transient receptor potential (TRP) channels are important mediators of sensory signals with marked effects on cellular functions and signalling pathways. Indeed, mutations in genes encoding TRP channels are the cause of several inherited diseases in humans (the so-called 'TRP channelopathies') that affect the cardiovascular, renal, skeletal and nervous systems. TRP channels are also promising targets for drug discovery. The initial focus of research was on TRP channels that are expressed on nociceptive neurons. Indeed, a number of potent, small-molecule TRPV1, TRPV3 and TRPA1 antagonists have already entered clinical trials as novel analgesic agents. There has been a recent upsurge in the amount of work that expands TRP channel drug discovery efforts into new disease areas such as asthma, cancer, anxiety, cardiac hypertrophy, as well as obesity and metabolic disorders. A better understanding of TRP channel functions in health and disease should lead to the discovery of first-in-class drugs for these intractable diseases. With this review, we hope to capture the current state of this rapidly expanding and changing field.
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Affiliation(s)
- Yosuke Kaneko
- Discovery Research Alliance, Ono Pharmaceutical Co. LtdOsaka, Japan
| | - Arpad Szallasi
- Department of Pathology and Laboratory Medicine, Monmouth Medical CenterLong Branch, NJ, USA
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Li PL, Zhang Y, Abais JM, Ritter JK, Zhang F. Cyclic ADP-Ribose and NAADP in Vascular Regulation and Diseases. ACTA ACUST UNITED AC 2013; 2:63-85. [PMID: 24749015 DOI: 10.1166/msr.2013.1022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cyclic ADP-ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP), two intracellular Ca2+ mobilizing second messengers, have been recognized as a fundamental signaling mechanism regulating a variety of cell or organ functions in different biological systems. Here we reviewed the literature regarding these ADP-ribosylcyclase products in vascular cells with a major focus on their production, physiological roles, and related underlying mechanisms mediating their actions. In particular, several hot topics in this area of research are comprehensively discussed, which may help understand some of the controversial evidence provided by different studies. For example, some new models are emerging for the agonist receptor coupling of CD38 or ADP-ribosylcyclase and for the formation of an acidic microenvironment to facilitate the production of NAADP in vascular cells. We also summarized the evidence regarding the NAADP-mediated two-phase Ca2+ release with a slow Ca2+-induced Ca2+ release (CICR) and corresponding physiological relevance. The possibility of a permanent structural space between lysosomes and sarcoplasmic reticulum (SR), as well as the critical role of lysosome trafficking in phase 2 Ca2+ release in response to some agonists are also explored. With respect to the molecular targets of NAADP within cells, several possible candidates including SR ryanodine receptors (RyRs), lysosomal transient receptor potential-mucolipin 1 (TRP-ML1) and two pore channels (TPCs) are presented with supporting and opposing evidence. Finally, the possible role of NAADP-mediated regulation of lysosome function in autophagy and atherogenesis is discussed, which may indicate a new direction for further studies on the pathological roles of cADPR and NAADP in the vascular system.
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Affiliation(s)
- Pin-Lan Li
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Yang Zhang
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Justine M Abais
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Joseph K Ritter
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
| | - Fan Zhang
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, VA 23298, USA
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Grimm C, Hassan S, Wahl-Schott C, Biel M. Role of TRPML and two-pore channels in endolysosomal cation homeostasis. J Pharmacol Exp Ther 2012; 342:236-44. [PMID: 22518024 DOI: 10.1124/jpet.112.192880] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The transient receptor potential (TRP) channels TRPML1, TRPML2, and TRPML3 (also called mucolipins 1-3 or MCOLN1-3) are nonselective cation channels. Mutations in the Trpml1 gene cause mucolipidosis type IV in humans with clinical features including psychomotor retardation, corneal clouding, and retinal degeneration, whereas mutations in the Trpml3 gene cause deafness, circling behavior, and coat color dilution in mice. No disease-causing mutations are reported for the Trpml2 gene. Like TRPML channels, which are expressed in the endolysosomal pathway, two-pore channels (TPCs), namely TPC1, TPC2, and TPC3, are found in intracellular organelles, in particular in endosomes and lysosomes. Both TRPML channels and TPCs may function as calcium/cation release channels in endosomes, lysosomes, and lysosome-related organelles with TRPMLs being activated by phosphatidylinositol 3,5-bisphosphate and regulated by pH and TPCs being activated by nicotinic acid adenine dinucleotide phosphate in a calcium- and pH-dependent manner. They may also be involved in endolysosomal transport and fusion processes, e.g., as intracellular calcium sources. Currently, however, the exact physiological roles of TRPML channels and TPCs remain quite elusive, and whether TRPML channels are purely endolysosomal ion channels or whether they may also be functionally active at the plasma membrane in vivo remains to be determined.
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Affiliation(s)
- Christian Grimm
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, 81377 Germany.
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Lima WC, Leuba F, Soldati T, Cosson P. Mucolipin controls lysosome exocytosis in Dictyostelium. J Cell Sci 2012; 125:2315-22. [PMID: 22357942 DOI: 10.1242/jcs.100362] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mucolipidosis type IV is a poorly understood lysosomal storage disease caused by alterations in the mucolipin lysosomal Ca(2+) channel. In this study, we generated mucolipin-knockout Dictyostelium cells, and observed that lysosome exocytosis was markedly increased in these cells compared with wild-type cells. In addition, mucolipin-knockout cells were more resistant to Ca(2+) deprivation, and the Ca(2+) concentration in their secretory lysosomes was decreased, suggesting that mucolipin transfers Ca(2+) ions from the cytosol to the lumen of secretory lysosomes. We speculate that mucolipin attenuates the fusogenic effect of local cytosolic increases in Ca(2+) by dissipating them into the lumen of lysosomal compartments.
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Affiliation(s)
- Wanessa C Lima
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland.
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Abstract
Phosphoinositides, especially phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] are required for the activity of many different ion channels. This chapter will highlight various aspects of this paradigm, by discussing current knowledge on four different ion channel families: inwardly rectifying K(+) (Kir) channels, KCNQ voltage gated K(+) channels, voltage gated Ca(2+) (VGCC) channels and Transient Receptor Potential (TRP) channels. Our main focus is to discuss functional aspects of this regulation, i.e. how changes in the concentration of PtdIns(4,5)P(2) in the plasma membrane upon phospholipase C activation may modulate the activity of ion channels, and what are the major determinants of this regulation. We also discuss how channels act as coincidence detectors sensing phosphoinositide levels and other signalling molecules. We also briefly discuss the available methods to study phosphoinositide regulation of ion channels, and structural aspects of interaction of ion channel proteins with these phospholipids. Finally, in several cases the effect of PtdIns(4,5)P(2) is more complex than a simple dependence of ion channel activity on the lipid, and we will discuss some these complexities.
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Affiliation(s)
- Nikita Gamper
- Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT, Leeds, UK,
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Molecular mechanisms of endolysosomal Ca2+ signalling in health and disease. Biochem J 2011; 439:349-74. [PMID: 21992097 DOI: 10.1042/bj20110949] [Citation(s) in RCA: 295] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Endosomes, lysosomes and lysosome-related organelles are emerging as important Ca2+ storage cellular compartments with a central role in intracellular Ca2+ signalling. Endocytosis at the plasma membrane forms endosomal vesicles which mature to late endosomes and culminate in lysosomal biogenesis. During this process, acquisition of different ion channels and transporters progressively changes the endolysosomal luminal ionic environment (e.g. pH and Ca2+) to regulate enzyme activities, membrane fusion/fission and organellar ion fluxes, and defects in these can result in disease. In the present review we focus on the physiology of the inter-related transport mechanisms of Ca2+ and H+ across endolysosomal membranes. In particular, we discuss the role of the Ca2+-mobilizing messenger NAADP (nicotinic acid adenine dinucleotide phosphate) as a major regulator of Ca2+ release from endolysosomes, and the recent discovery of an endolysosomal channel family, the TPCs (two-pore channels), as its principal intracellular targets. Recent molecular studies of endolysosomal Ca2+ physiology and its regulation by NAADP-gated TPCs are providing exciting new insights into the mechanisms of Ca2+-signal initiation that control a wide range of cellular processes and play a role in disease. These developments underscore a new central role for the endolysosomal system in cellular Ca2+ regulation and signalling.
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Wakabayashi K, Gustafson AM, Sidransky E, Goldin E. Mucolipidosis type IV: an update. Mol Genet Metab 2011; 104:206-13. [PMID: 21763169 PMCID: PMC3205274 DOI: 10.1016/j.ymgme.2011.06.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 06/09/2011] [Accepted: 06/09/2011] [Indexed: 11/28/2022]
Abstract
Mucolipidosis type IV (MLIV) is a neurodevelopmental as well as neurodegenerative disorder with severe psychomotor developmental delay, progressive visual impairment, and achlorydria. It is characterized by the presence of lysosomal inclusions in many cell types in patients. MLIV is an autosomal recessive disease caused by mutations in MCOLN1, which encodes for mucolipin-1, a member of the transient receptor potential (TRP) cation channel family. Although approximately 70-80% of patients identified are Ashkenazi Jewish, MLIV is a pan-ethnic disorder. Importantly, while MLIV is thought to be a rare disease, its frequency may be greater than currently appreciated, for its common presentation as a cerebral palsy-like encephalopathy can lead to misdiagnosis. Moreover, patients with milder variants are often not recognized as having MLIV. This review provides an update on the ethnic distribution, clinical manifestations, laboratory findings, methods of diagnosis, molecular genetics, differential diagnosis, and treatment of patients with MLIV. An enhanced awareness of the manifestations of this disorder may help to elucidate the true frequency and range of symptoms associated with MLIV, providing insight into the pathogenesis of this multi-system disease.
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Affiliation(s)
| | | | - Ellen Sidransky
- Section on Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Building 35, Room 1A213, 35 Convent Dr., MSC 3708, Bethesda, MD 20892-3708
| | - Ehud Goldin
- Section on Molecular Neurogenetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Building 35, Room 1A213, 35 Convent Dr., MSC 3708, Bethesda, MD 20892-3708
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Lloyd-Evans E, Platt FM. Lysosomal Ca(2+) homeostasis: role in pathogenesis of lysosomal storage diseases. Cell Calcium 2011; 50:200-5. [PMID: 21724254 DOI: 10.1016/j.ceca.2011.03.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 03/21/2011] [Accepted: 03/24/2011] [Indexed: 01/07/2023]
Abstract
Disrupted cellular Ca(2+) signaling is believed to play a role in a number of human diseases including lysosomal storage diseases (LSD). LSDs are a group of ∼50 diseases caused predominantly by mutations in lysosomal proteins that result in accumulation of macromolecules within the lysosome. We recently reported that Niemann-Pick type C (NPC) is the first human disease to be associated with defective lysosomal Ca(2+) uptake and defective NAADP-mediated lysosomal Ca(2+) release. These defects in NPC cells leads to the disruption in endocytosis and subsequent lipid storage that is a feature of this disease. In contrast, Chediak-Higashi Syndrome cells have been reported to have enhanced lysosomal Ca(2+) uptake whilst the TRPML1 protein defective in mucolipidosis type IV is believed to function as a Ca(2+) channel. In this review we provide a summary of the current knowledge on the role of lysosomal Ca(2+) signaling in the pathogenesis of this group of diseases.
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Affiliation(s)
- Emyr Lloyd-Evans
- School of Biosciences, Biomedical Sciences Building, Cardiff University, Museum Avenue, Cardiff CF10 3AX, United Kingdom.
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Schultz ML, Tecedor L, Chang M, Davidson BL. Clarifying lysosomal storage diseases. Trends Neurosci 2011; 34:401-10. [PMID: 21723623 DOI: 10.1016/j.tins.2011.05.006] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 05/17/2011] [Accepted: 05/27/2011] [Indexed: 11/29/2022]
Abstract
Lysosomal storage diseases (LSDs) are a class of metabolic disorders caused by mutations in proteins critical for lysosomal function. Such proteins include lysosomal enzymes, lysosomal integral membrane proteins, and proteins involved in the post-translational modification and trafficking of lysosomal proteins. There are many recognized forms of LSDs and, although individually rare, their combined prevalence is estimated to be 1 in 8000 births. Over two-thirds of LSDs involve central nervous system (CNS) dysfunction (progressive cognitive and motor decline) and these symptoms are often the most debilitating. Although the genetic basis for these disorders is clear and the biochemistry of the proteins well understood, the cellular mechanisms by which deficiencies in these proteins disrupt neuronal viability remain ambiguous. In this review, we provide an overview of the widespread cellular perturbations occurring in LSDs, how they might be linked and interventions that may specifically or globally correct those defects.
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Affiliation(s)
- Mark L Schultz
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
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Chandra M, Zhou H, Li Q, Muallem S, Hofmann SL, Soyombo AA. A role for the Ca2+ channel TRPML1 in gastric acid secretion, based on analysis of knockout mice. Gastroenterology 2011; 140:857-67. [PMID: 21111738 PMCID: PMC3057336 DOI: 10.1053/j.gastro.2010.11.040] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 11/03/2010] [Accepted: 11/10/2010] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Mutations in TRPML1, a lysosomal Ca(2+)-permeable TRP channel, lead to mucolipidosis type IV, a neurodegenerative lysosomal storage disease. An unusual feature of mucolipidosis type IV is constitutive achlorhydria. We produced Trpml1(-/-) (null) mice to investigate the requirement for this protein in gastric acid secretion. METHODS Trpml1-null mice were generated by gene targeting. The expression of Trpml1 and its role in acid secretion by gastric parietal cells were analyzed using biochemical, histologic, and ultrastructural approaches. RESULTS Trpml1 is expressed by parietal cells and localizes predominantly to the lysosomes; it was dynamically palmitoylated and dephosphorylated in vivo following histamine stimulation of acid secretion. Trpml1-null mice had significant impairments in basal and histamine-stimulated gastric acid secretion and markedly reduced levels of the gastric proton pump. Histologic and ultrastructural analyses revealed that Trpml1(-/-) parietal cells were enlarged, had multivesicular and multi-lamellated lysosomes, and maintained an abnormal intracellular canalicular membrane. The intralysosomal Ca(2+) content and receptor-mediated Ca(2+) signaling were, however, unaffected in Trpml1(-/-) gastric glands, indicating that Trpml1 does not function in the regulation of lysosomal Ca(2+). CONCLUSIONS Loss of Trpml1 causes reduced levels and mislocalization of the gastric proton pump and alters the secretory canaliculi, causing hypochlorhydria and hypergastrinemia. The lysosomal enlargement and defective intracellular canaliculi formation observed in Trpml1(-/-) parietal cells indicate that Trpml1 functions in the formation and trafficking of the tubulovesicles. This study provides direct evidence for the regulation of gastric acid secretion by a TRP channel; TRPML1 is an important protein in parietal cell apical membrane trafficking.
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Affiliation(s)
- Manjari Chandra
- Department of Internal Medicine, University of Texas, Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Hua Zhou
- Department of Internal Medicine, University of Texas, Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Qin Li
- Department of Physiology, University of Texas, Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Shmuel Muallem
- Department of Physiology, University of Texas, Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390, USA,Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, USA
| | - Sandra L. Hofmann
- Department of Internal Medicine, University of Texas, Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Abigail A. Soyombo
- Department of Internal Medicine, University of Texas, Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390, USA,Address correspondence to: Abigail A. Soyombo, Ph.D., Department of Internal Medicine, University of Texas, Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, Texas 75390-8593, USA, Tel: 214-648-1456, Fax: 214-648-4940,
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LaPlante JM, Falardeau JL, Brown EM, Slaugenhaupt SA, Vassilev PM. The cation channel mucolipin-1 is a bifunctional protein that facilitates membrane remodeling via its serine lipase domain. Exp Cell Res 2011; 317:691-705. [PMID: 21256127 DOI: 10.1016/j.yexcr.2011.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 12/03/2010] [Accepted: 01/05/2011] [Indexed: 11/19/2022]
Abstract
Phospholipase modulators have been shown to affect the topology of lipid bilayers and the formation of tubulo-vesicular structures, but the specific endogenous phospholipases involved have yet to be identified. Here we show that TRPML1 (MLN1), a Ca(2+)-permeable channel, contributes to membrane remodeling through a serine lipase consensus domain, and thus represents a novel type of bifunctional protein. Remarkably, this serine lipase active site determines the ability of MLN1 to generate tubulo-vesicular extensions in mucolipin-1-expressing oocytes, human fibroblasts and model membrane vesicles. Our demonstration that MLN1 is involved in membrane remodeling and the formation of extensions suggests that it may play a role in the formation of cellular processes linked to the late endosome/lysosome (LE/L) pathway. MLN1 is absent or mutated in patients with mucolipidosis IV (MLIV), a lysosomal disorder with devastating neurological and other consequences. This study provides potential insight into the pathophysiology of MLIV.
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Affiliation(s)
- Janice M LaPlante
- Division of Endocrinology, Diabetes and Hypertension and Membrane Biology Program, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Transient Receptor Potential Genes and Human Inherited Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:1011-32. [DOI: 10.1007/978-94-007-0265-3_52] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
MLIV (mucolipidosis type IV) is a neurodegenerative lysosomal storage disorder caused by mutations in MCOLN1, a gene that encodes TRPML1 (mucolipin-1), a member of the TRPML (transient receptor potential mucolipin) cation channels. Two additional homologues are TRPML2 and TRPML3 comprising the TRPML subgroup in the TRP superfamily. The three proteins play apparently key roles along the endocytosis process, and thus their cellular localization varies among the different group members. Thus TRPML1 is localized exclusively to late endosomes and lysosomes, TRPML2 is primarily located in the recycling clathrin-independent GPI (glycosylphosphatidylinositol)-anchored proteins and early endosomes, and TRPML3 is primarily located in early endosomes. Apparently, all three proteins' main physiological function underlies Ca2+ channelling, regulating the endocytosis process. Recent findings also indicate that the three TRPML proteins form heteromeric complexes at least in some of their cellular content. The physiological role of these complexes in lysosomal function remains to be elucidated, as well as their effect on the pathophysiology of MLIV. Another open question is whether any one of the TRPMLs bears additional function in channel activity
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Gees M, Colsoul B, Nilius B. The role of transient receptor potential cation channels in Ca2+ signaling. Cold Spring Harb Perspect Biol 2010; 2:a003962. [PMID: 20861159 DOI: 10.1101/cshperspect.a003962] [Citation(s) in RCA: 310] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The 28 mammalian members of the super-family of transient receptor potential (TRP) channels are cation channels, mostly permeable to both monovalent and divalent cations, and can be subdivided into six main subfamilies: the TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), and the TRPA (ankyrin) groups. TRP channels are widely expressed in a large number of different tissues and cell types, and their biological roles appear to be equally diverse. In general, considered as polymodal cell sensors, they play a much more diverse role than anticipated. Functionally, TRP channels, when activated, cause cell depolarization, which may trigger a plethora of voltage-dependent ion channels. Upon stimulation, Ca2+ permeable TRP channels generate changes in the intracellular Ca2+ concentration, [Ca2+]i, by Ca2+ entry via the plasma membrane. However, more and more evidence is arising that TRP channels are also located in intracellular organelles and serve as intracellular Ca2+ release channels. This review focuses on three major tasks of TRP channels: (1) the function of TRP channels as Ca2+ entry channels; (2) the electrogenic actions of TRPs; and (3) TRPs as Ca2+ release channels in intracellular organelles.
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Affiliation(s)
- Maarten Gees
- KU Leuven, Department of Molecular Cell Biology, Laboratory Ion Channel Research, Campus Gasthuisberg, Herestraat 49, bus 802, Leuven, Belgium
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