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Ghasemi A, Eslami Ardakani M, Togha M, Yazdi N, Lang AE, Amini E, Rohani M, Alavi A. A Novel Homozygous Variant in the MCOLN1 Gene Associated With Severe Oromandibular Dystonia and Parkinsonism. Can J Neurol Sci 2024:1-9. [PMID: 38532569 DOI: 10.1017/cjn.2024.47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
BACKGROUND Mucolipidosis type IV (MLIV) is a rare, progressive lysosomal storage disorder characterized by severe intellectual disability, delayed motor milestones and ophthalmologic abnormalities. MLIV is an autosomal recessive disease caused by mutations in the MCOLN1 gene, encoding mucolipin-1 which is responsible for maintaining lysosomal function. OBJECTIVES AND METHODS Here, we report a family of four Iranian siblings with cognitive decline, progressive visual and pyramidal disturbances, and abnormal movements manifested by severe oromandibular dystonia and parkinsonism. MRI scans of the brain demonstrated signal abnormalities in the white matter and thinning of the corpus callosum. RESULTS AND CONCLUSIONS Whole-exome sequencing identified a novel homozygous variant, c.362C > T:p. Thr121Met in the MCOLN1 gene consistent with a diagnosis of MLIV. The presentation of MLIV may overlap with a variety of other neurological diseases, and genetic analysis is an important strategy to clarify the diagnosis. This is an important point that clinicians should be familiar with. The novel variant c.362C > T:p. Thr121Met herein described may be related to a comparatively older age at onset. Our study also expands the clinical spectrum of MLIV associated with the MCOLN1 variants and introduces a novel likely pathogenic variant for testing in MLIV cases that remain unresolved.
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Affiliation(s)
- Aida Ghasemi
- Student Research Committee, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Genetics research center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Neuromuscular Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahdieh Eslami Ardakani
- Neurology Ward, School of Medicine, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mansoureh Togha
- Neurology Ward, School of Medicine, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Narges Yazdi
- Department of Neurology, School of Medicine, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Anthony E Lang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
- Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman. Movement Disorders Clinic, Toronto Western Hospital and Division of Neurology, Toronto, ON, Canada
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Elahe Amini
- Department of Neurology, School of Medicine, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
- Skull Base Research Center, The Five Senses Health Institute Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Rohani
- Department of Neurology, School of Medicine, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Afagh Alavi
- Genetics research center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- Neuromuscular Research Center, Tehran University of Medical Sciences, Tehran, Iran
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Sasazawa Y, Hattori N, Saiki S. JNK-interacting protein 4 is a central molecule for lysosomal retrograde trafficking. Bioessays 2023; 45:e2300052. [PMID: 37559169 DOI: 10.1002/bies.202300052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/11/2023]
Abstract
Lysosomal positioning is an important factor in regulating cellular responses, including autophagy. Because proteins encoded by disease-responsible genes are involved in lysosomal trafficking, proper intracellular lysosomal trafficking is thought to be essential for cellular homeostasis. In the past few years, the mechanisms of lysosomal trafficking have been elucidated with a focus on adapter proteins linking motor proteins to lysosomes. Here, we outline recent findings on the mechanisms of lysosomal trafficking by focusing on adapter protein c-Jun NH2 -terminal kinase-interacting protein (JIP) 4, which plays a central role in this process, and other JIP4 functions and JIP family proteins. Additionally, we discuss neuronal diseases associated with aberrance in the JIP family protein. Accumulating evidence suggests that chemical manipulation of lysosomal positioning may be a therapeutic approach for these neuronal diseases.
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Affiliation(s)
- Yukiko Sasazawa
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
- Department of Neurology, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Shinji Saiki
- Department of Neurology, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, Japan
- Department of Neurology, Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
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Zhang M, Ma Y, Ye X, Zhang N, Pan L, Wang B. TRP (transient receptor potential) ion channel family: structures, biological functions and therapeutic interventions for diseases. Signal Transduct Target Ther 2023; 8:261. [PMID: 37402746 DOI: 10.1038/s41392-023-01464-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 03/26/2023] [Accepted: 04/25/2023] [Indexed: 07/06/2023] Open
Abstract
Transient receptor potential (TRP) channels are sensors for a variety of cellular and environmental signals. Mammals express a total of 28 different TRP channel proteins, which can be divided into seven subfamilies based on amino acid sequence homology: TRPA (Ankyrin), TRPC (Canonical), TRPM (Melastatin), TRPML (Mucolipin), TRPN (NO-mechano-potential, NOMP), TRPP (Polycystin), TRPV (Vanilloid). They are a class of ion channels found in numerous tissues and cell types and are permeable to a wide range of cations such as Ca2+, Mg2+, Na+, K+, and others. TRP channels are responsible for various sensory responses including heat, cold, pain, stress, vision and taste and can be activated by a number of stimuli. Their predominantly location on the cell surface, their interaction with numerous physiological signaling pathways, and the unique crystal structure of TRP channels make TRPs attractive drug targets and implicate them in the treatment of a wide range of diseases. Here, we review the history of TRP channel discovery, summarize the structures and functions of the TRP ion channel family, and highlight the current understanding of the role of TRP channels in the pathogenesis of human disease. Most importantly, we describe TRP channel-related drug discovery, therapeutic interventions for diseases and the limitations of targeting TRP channels in potential clinical applications.
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Affiliation(s)
- Miao Zhang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
- Experiment Center for Science and Technology, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
- The Center for Microbes, Development and Health; Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Yueming Ma
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Xianglu Ye
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Ning Zhang
- Experiment Center for Science and Technology, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - Lei Pan
- The Center for Microbes, Development and Health; Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, 200031, China.
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Bing Wang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
- Center for Pharmaceutics Research, Shanghai Institute of Materia Medica Chinese Academy of Sciences, Shanghai, 201203, China.
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Wahl-Schott C, Freichel M, Hennis K, Philippaert K, Ottenheijm R, Tsvilovskyy V, Varbanov H. Characterization of Endo-Lysosomal Cation Channels Using Calcium Imaging. Handb Exp Pharmacol 2023; 278:277-304. [PMID: 36894791 DOI: 10.1007/164_2023_637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Endo-lysosomes are membrane-bound acidic organelles that are involved in endocytosis, recycling, and degradation of extracellular and intracellular material. The membranes of endo-lysosomes express several Ca2+-permeable cation ion channels, including two-pore channels (TPC1-3) and transient receptor potential mucolipin channels (TRPML1-3). In this chapter, we will describe four different state-of-the-art Ca2+ imaging approaches, which are well-suited to investigate the function of endo-lysosomal cation channels. These techniques include (1) global cytosolic Ca2+ measurements, (2) peri-endo-lysosomal Ca2+ imaging using genetically encoded Ca2+ sensors that are directed to the cytosolic endo-lysosomal membrane surface, (3) Ca2+ imaging of endo-lysosomal cation channels, which are engineered in order to redirect them to the plasma membrane in combination with approaches 1 and 2, and (4) Ca2+ imaging by directing Ca2+ indicators to the endo-lysosomal lumen. Moreover, we will review useful small molecules, which can be used as valuable tools for endo-lysosomal Ca2+ imaging. Rather than providing complete protocols, we will discuss specific methodological issues related to endo-lysosomal Ca2+ imaging.
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Affiliation(s)
- Christian Wahl-Schott
- Institut für Kardiovaskuläre Physiologie und Pathophysiologie, Lehrstuhl für Vegetative Physiologie, Biomedizinisches Zentrum, Ludwig-Maximilians-Universität München, München, Germany.
| | - Marc Freichel
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany. .,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany.
| | - Konstantin Hennis
- Institut für Kardiovaskuläre Physiologie und Pathophysiologie, Lehrstuhl für Vegetative Physiologie, Biomedizinisches Zentrum, Ludwig-Maximilians-Universität München, München, Germany
| | - Koenraad Philippaert
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Roger Ottenheijm
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Volodymyr Tsvilovskyy
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Hristo Varbanov
- Institut für Neurophysiologie, Medizinische Hochschule Hannover(MHH), Hannover, Germany
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Amaral O, Martins M, Oliveira AR, Duarte AJ, Mondragão-Rodrigues I, Macedo MF. The Biology of Lysosomes: From Order to Disorder. Biomedicines 2023; 11:213. [PMID: 36672721 PMCID: PMC9856021 DOI: 10.3390/biomedicines11010213] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/30/2022] [Accepted: 01/11/2023] [Indexed: 01/19/2023] Open
Abstract
Since its discovery in 1955, the understanding of the lysosome has continuously increased. Once considered a mere waste removal system, the lysosome is now recognised as a highly crucial cellular component for signalling and energy metabolism. This notable evolution raises the need for a summarized review of the lysosome's biology. As such, throughout this article, we will be compiling the current knowledge regarding the lysosome's biogenesis and functions. The comprehension of this organelle's inner mechanisms is crucial to perceive how its impairment can give rise to lysosomal disease (LD). In this review, we highlight some examples of LD fine-tuned mechanisms that are already established, as well as others, which are still under investigation. Even though the understanding of the lysosome and its pathologies has expanded through the years, some of its intrinsic molecular aspects remain unknown. In order to illustrate the complexity of the lysosomal diseases we provide a few examples that have challenged the established single gene-single genetic disorder model. As such, we believe there is a strong need for further investigation of the exact abnormalities in the pathological pathways in lysosomal disease.
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Affiliation(s)
- Olga Amaral
- Departamento de Genética Humana, Unidade de Investigação e Desenvolvimento, Instituto Nacional de Saúde Ricardo Jorge (INSA), 4000-055 Porto, Portugal
- Centro de Estudos de Ciência Animal (CECA, ICETA), Universidade do Porto, 4485-661 Porto, Portugal
- Laboratório Associado para Ciência Animal e Veterinária (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - Mariana Martins
- Departamento de Ciências Médicas, Universidade de Aveiro, Campus Universitário de Santiago, Agra do Crasto, Edifício 30, 3810-193 Aveiro, Portugal
| | - Ana Rita Oliveira
- Departamento de Ciências Médicas, Universidade de Aveiro, Campus Universitário de Santiago, Agra do Crasto, Edifício 30, 3810-193 Aveiro, Portugal
| | - Ana Joana Duarte
- Departamento de Genética Humana, Unidade de Investigação e Desenvolvimento, Instituto Nacional de Saúde Ricardo Jorge (INSA), 4000-055 Porto, Portugal
- Centro de Estudos de Ciência Animal (CECA, ICETA), Universidade do Porto, 4485-661 Porto, Portugal
- Laboratório Associado para Ciência Animal e Veterinária (AL4AnimalS), 1300-477 Lisboa, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, 4050-313 Porto, Portugal
| | - Inês Mondragão-Rodrigues
- Departamento de Ciências Médicas, Universidade de Aveiro, Campus Universitário de Santiago, Agra do Crasto, Edifício 30, 3810-193 Aveiro, Portugal
- CAGE, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - M. Fátima Macedo
- Departamento de Ciências Médicas, Universidade de Aveiro, Campus Universitário de Santiago, Agra do Crasto, Edifício 30, 3810-193 Aveiro, Portugal
- CAGE, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
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Abstract
Ca2+ is a universal second messenger that plays a wide variety of fundamental roles in cellular physiology. Thus, to warrant selective responses and to allow rapid mobilization upon specific stimuli, Ca2+ is accumulated in organelles to keep it at very low levels in the cytoplasm during resting conditions. Major Ca2+ storage organelles include the endoplasmic reticulum (ER), the mitochondria, and as recently demonstrated, the lysosome (Xu and Ren, Annu Rev Physiol 77:57-80, 2015). The importance of Ca2+ signaling deregulation in human physiology is underscored by its involvement in several human diseases, including lysosomal storage disorders, neurodegenerative disease and cancer (Shen et al., Nat Commun 3:731, 2012; Bae et al., J Neurosci 34:11485-11503, 2014). Recent evidence strongly suggests that lysosomal Ca2+ plays a major role in the regulation of lysosomal adaptation to nutrient availability through a lysosomal signaling pathway involving the lysosomal Ca2+ channel TRPML1 and the transcription factor TFEB, a master regulator for lysosomal function and autophagy (Sardiello et al., Science 325:473-477, 2009; Settembre et al., Science 332:1429-1433, 2011; Medina et al., Nat Cell Biol 17:288-299, 2015; Di Paola et al., Cell Calcium 69:112-121, 2018). Due to the tight relationship of this lysosomal Ca2+ channel and TFEB, in this chapter, we will focus on the role of the TRPML1/TFEB pathway in the regulation of lysosomal function and autophagy.
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Affiliation(s)
- Diego Luis Medina
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Naples, Italy.
- Medical Genetics Unit, Department of Medical and Translational Science, Federico II University, Naples, Italy.
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Allan CY, Fisher PR. The Dictyostelium Model for Mucolipidosis Type IV. Front Cell Dev Biol 2022; 10:741967. [PMID: 35493081 PMCID: PMC9043695 DOI: 10.3389/fcell.2022.741967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 03/21/2022] [Indexed: 12/02/2022] Open
Abstract
Mucolipidosis type IV, a devastating neurological lysosomal disease linked to mutations in the transient receptor potential channel mucolipin 1, TRPML1, a calcium permeable channel in the membranes of vesicles in endolysosomal system. TRPML1 function is still being elucidated and a better understanding of the molecular pathogenesis of Mucolipidosis type IV, may facilitate development of potential treatments. We have created a model to study mucolipin function in the eukaryotic slime mould Dictyostelium discoideum by altering expression of its single mucolipin homologue, mcln. We show that in Dictyostelium mucolipin overexpression contributes significantly to global chemotactic calcium responses in vegetative and differentiated cells. Knockdown of mucolipin also enhances calcium responses in vegetative cells but does not affect responses in 6–7 h developed cells, suggesting that in developed cells mucolipin may help regulate local calcium signals rather than global calcium waves. We found that both knocking down and overexpressing mucolipin often, but not always, presented the same phenotypes. Altering mucolipin expression levels caused an accumulation or increased acidification of Lysosensor Blue stained vesicles in vegetative cells. Nutrient uptake by phagocytosis and macropinocytosis were increased but growth rates were not, suggesting defects in catabolism. Both increasing and decreasing mucolipin expression caused the formation of smaller slugs and larger numbers of fruiting bodies during multicellular development, suggesting that mucolipin is involved in initiation of aggregation centers. The fruiting bodies that formed from these smaller aggregates had proportionately larger basal discs and thickened stalks, consistent with a regulatory role for mucolipin-dependent Ca2+ signalling in the autophagic cell death pathways involved in stalk and basal disk differentiation in Dictyostelium. Thus, we have provided evidence that mucolipin contributes to chemotactic calcium signalling and that Dictyostelium is a useful model to study the molecular mechanisms involved in the cytopathogenesis of Mucolipidosis type IV.
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Krogsaeter E, Rosato AS, Grimm C. TRPMLs and TPCs: targets for lysosomal storage and neurodegenerative disease therapy? Cell Calcium 2022; 103:102553. [DOI: 10.1016/j.ceca.2022.102553] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/04/2022] [Accepted: 02/04/2022] [Indexed: 12/25/2022]
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Vardi A, Pri-Or A, Wigoda N, Grishchuk Y, Futerman AH. Proteomics analysis of a human brain sample from a mucolipidosis type IV patient reveals pathophysiological pathways. Orphanet J Rare Dis 2021; 16:39. [PMID: 33478506 PMCID: PMC7818904 DOI: 10.1186/s13023-021-01679-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/06/2021] [Indexed: 12/29/2022] Open
Abstract
Background Mucolipidosis type IV (MLIV), an ultra-rare neurodevelopmental and neurodegenerative disorder, is caused by mutations in the MCOLN1 gene, which encodes the late endosomal/lysosomal transient receptor potential channel TRPML1 (mucolipin 1). The precise pathophysiogical pathways that cause neurological disease in MLIV are poorly understood. Recently, the first post-mortem brain sample became available from a single MLIV patient, and in the current study we performed mass spectrometry (MS)-based proteomics on this tissue with a view to delineating pathological pathways, and to compare with previously-published data on MLIV, including studies using the Mcoln1−/− mouse. Results A number of pathways were altered in two brain regions from the MLIV patient, including those related to the lysosome, lipid metabolism, myelination, cellular trafficking and autophagy, mTOR and calmodulin, the complement system and interferon signaling. Of these, levels of some proteins not known previously to be associated with MLIV were altered, including APOD, PLIN4, ATG and proteins related to interferon signaling. Moreover, when proteins detected by proteomics in the human brain were compared with their orthologs detected in the Mcoln1−/− mouse by RNAseq, the results were remarkably similar. Finally, analysis of proteins in human and mouse CSF suggest that calbindin 1 and calbindin 2 might be useful as biomarkers to help chart the course of disease development. Conclusions Despite the sample size limitations, our findings are consistent with the relatively general changes in lysosomal function previously reported in MLIV, and shed light on new pathways of disease pathophysiology, which is required in order to understand the course of disease development and to determine the efficacy of therapies when they become available for this devastating disease.
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Affiliation(s)
- Ayelet Vardi
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Amir Pri-Or
- The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Noa Wigoda
- The Life Sciences Core Facilities, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Yulia Grishchuk
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital Research Institute, Harvard Medical School, 185 Cambridge St., Boston, MA, 02114, USA
| | - Anthony H Futerman
- Department of Biomolecular Sciences, Weizmann Institute of Science, 76100, Rehovot, Israel.
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Li G, Li PL. Lysosomal TRPML1 Channel: Implications in Cardiovascular and Kidney Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:275-301. [PMID: 35138619 PMCID: PMC9899368 DOI: 10.1007/978-981-16-4254-8_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lysosomal ion channels mediate ion flux from lysosomes and regulate membrane potential across the lysosomal membrane, which are essential for lysosome biogenesis, nutrient sensing, lysosome trafficking, lysosome enzyme activity, and cell membrane repair. As a cation channel, the transient receptor potential mucolipin 1 (TRPML1) channel is mainly expressed on lysosomes and late endosomes. Recently, the normal function of TRPML1 channels has been demonstrated to be important for the maintenance of cardiovascular and renal glomerular homeostasis and thereby involved in the pathogenesis of some cardiovascular and kidney diseases. In arterial myocytes, it has been found that Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP), an intracellular second messenger, can induce Ca2+ release through the lysosomal TRPML1 channel, leading to a global Ca2+ release response from the sarcoplasmic reticulum (SR). In podocytes, it has been demonstrated that lysosomal TRPML1 channels control lysosome trafficking and exosome release, which contribute to the maintenance of podocyte functional integrity. The defect or functional deficiency of lysosomal TRPML1 channels has been shown to critically contribute to the initiation and development of some chronic degeneration or diseases in the cardiovascular system or kidneys. Here we briefly summarize the current evidence demonstrating the regulation of lysosomal TRPML1 channel activity and related signaling mechanisms. We also provide some insights into the canonical and noncanonical roles of TRPML1 channel dysfunction as a potential pathogenic mechanism for certain cardiovascular and kidney diseases and associated therapeutic strategies.
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Affiliation(s)
- Guangbi Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA.
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Temporal analysis of localization and trafficking of glycolipids. Biochem Biophys Res Commun 2020; 532:19-24. [PMID: 32826055 DOI: 10.1016/j.bbrc.2020.06.083] [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: 05/28/2020] [Accepted: 06/17/2020] [Indexed: 11/24/2022]
Abstract
Glycolipid metabolism occurs in the Golgi apparatus, but the detailed mechanisms have not yet been elucidated. We used fluorescently labeled glycolipids to analyze glycolipid composition and localization changes and shed light on glycolipid metabolism. In a previous study, the fatty chain of lactosyl ceramide was fluorescently labeled with BODIPY (LacCer-BODIPY) before being introduced into cultured cells to analyze the cell membrane glycolipid recycling process. However, imaging analysis of glycolipid recycling is difficult because of limited spatial resolution. Therefore, we examined the microscopic conditions that allow the temporal analysis of LacCer-BODIPY trafficking and localization. We observed that the glycolipid fluorescent probe migrated from the cell membrane to intracellular organelles before returning to the cell membrane. We used confocal microscopy to observe co-localization of the glycolipid probe with endosomes and Golgi markers, demonstrating that it recycles mainly through the trans-Golgi network (TGN). Here, a glycolipid recycling pathway was observed that did not require the lipids to pass through the lysosome.
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Two-pore and TRPML cation channels: Regulators of phagocytosis, autophagy and lysosomal exocytosis. Pharmacol Ther 2020; 220:107713. [PMID: 33141027 DOI: 10.1016/j.pharmthera.2020.107713] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/19/2020] [Indexed: 02/07/2023]
Abstract
The old Greek saying "Panta Rhei" ("everything flows") is true for all life and all living things in general. It also becomes nicely evident when looking closely into cells. There, material from the extracellular space is taken up by endocytic processes and transported to endosomes where it is sorted either for recycling or degradation. Cargo is also packaged for export through exocytosis involving the Golgi network, lysosomes and other organelles. Everything in this system is in constant motion and many proteins are necessary to coordinate transport along the different intracellular pathways to avoid chaos. Among these proteins are ion channels., in particular TRPML channels (mucolipins) and two-pore channels (TPCs) which reside on endosomal and lysosomal membranes to speed up movement between organelles, e.g. by regulating fusion and fission; they help readjust pH and osmolarity changes due to such processes, or they promote exocytosis of export material. Pathophysiologically, these channels are involved in neurodegenerative, metabolic, retinal and infectious diseases, cancer, pigmentation defects, and immune cell function, and thus have been proposed as novel pharmacological targets, e.g. for the treatment of lysosomal storage disorders, Duchenne muscular dystrophy, or different types of cancer. Here, we discuss the similarities but also differences of TPCs and TRPMLs in regulating phagocytosis, autophagy and lysosomal exocytosis, and we address the contradictions and open questions in the field relating to the roles TPCs and TRPMLs play in these different processes.
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Jezela-Stanek A, Ciara E, Stepien KM. Neuropathophysiology, Genetic Profile, and Clinical Manifestation of Mucolipidosis IV-A Review and Case Series. Int J Mol Sci 2020; 21:ijms21124564. [PMID: 32604955 PMCID: PMC7348969 DOI: 10.3390/ijms21124564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/21/2020] [Accepted: 06/23/2020] [Indexed: 12/23/2022] Open
Abstract
Mucolipidosis type IV (MLIV) is an ultra-rare lysosomal storage disorder caused by biallelic mutations in MCOLN1 gene encoding the transient receptor potential channel mucolipin-1. So far, 35 pathogenic or likely pathogenic MLIV-related variants have been described. Clinical manifestations include severe intellectual disability, speech deficit, progressive visual impairment leading to blindness, and myopathy. The severity of the condition may vary, including less severe psychomotor delay and/or ocular findings. As no striking recognizable facial dysmorphism, skeletal anomalies, organomegaly, or lysosomal enzyme abnormalities in serum are common features of MLIV, the clinical diagnosis may be significantly improved because of characteristic ophthalmological anomalies. This review aims to outline the pathophysiology and genetic defects of this condition with a focus on the genotype–phenotype correlation amongst cases published in the literature. The authors will present their own clinical observations and long-term outcomes in adult MLIV cases.
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Affiliation(s)
- Aleksandra Jezela-Stanek
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, 01-138 Warsaw, Poland;
| | - Elżbieta Ciara
- Department of Medical Genetics, The Children’s Memorial Heath Institute, 04-730 Warsaw, Poland;
| | - Karolina M. Stepien
- Adult Inherited Metabolic Diseases, Salford Royal NHS Foundation Trust, Salford M6 8HD, UK
- Correspondence:
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Arai K, Ohtake A, Daikoku S, Suzuki K, Ito Y, Kabayama K, Fukase K, Kanie Y, Kanie O. Discrimination of cellular developmental states focusing on glycan transformation and membrane dynamics by using BODIPY-tagged lactosyl ceramides. Org Biomol Chem 2020; 18:3724-3733. [PMID: 32364197 DOI: 10.1039/d0ob00547a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Glycosphingolipids (GSLs) are a group of molecules composed of a hydrophilic glycan part and a hydrophobic ceramide creating a diverse family. GSLs are de novo synthesised from ceramides at the endoplasmic reticulum and Golgi apparatus, and transported to the outer surface of the plasma membrane. It has been known that the glycan structures of GSLs change reflecting disease states. We envisioned that analysing the glycan pattern of GSLs enables distinguishing diseases. For this purpose, we utilised a fluorescently tagged compound, LacCerBODIPY (1). At first, compound 1 was taken up by cultured PC12D cells and transformed into various GSLs. As a result, changes in the GSL patterns of differentiation states of the cells were successfully observed by using an analysis platform, nano-liquid chromatography (LC)-fluorescence detection (FLD)-electrospray ionisation (ESI)-mass spectrometry (MS), which could quantify and provide molecular ions simultaneously. We found that compound 1 remained for about 10 min on the plasma membrane before it was converted into other GSLs. We therefore investigated a more rapid way to discriminate different cellular states by fluorescence recovery after photobleaching, which revealed that it is possible to distinguish the differentiation states as well.
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Affiliation(s)
- Kenta Arai
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Atsuko Ohtake
- Synthetic Cellular Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Satama 351-0198, Japan
| | - Shusaku Daikoku
- Synthetic Cellular Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Satama 351-0198, Japan
| | - Katsuhiko Suzuki
- Faculty of Pharmaceutical Sciences, Aomori University, 2-3-1 Kohbata, Aomori 030-0943, Japan
| | - Yukishige Ito
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan and Synthetic Cellular Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Satama 351-0198, Japan
| | - Kazuya Kabayama
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan and Micro/Nano Technology Center, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan.
| | - Koichi Fukase
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yoshimi Kanie
- Research promotion division, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
| | - Osamu Kanie
- Micro/Nano Technology Center, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan. and Department of Applied Biochemistry, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
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15
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Clement D, Goodridge JP, Grimm C, Patel S, Malmberg KJ. TRP Channels as Interior Designers: Remodeling the Endolysosomal Compartment in Natural Killer Cells. Front Immunol 2020; 11:753. [PMID: 32411146 PMCID: PMC7198808 DOI: 10.3389/fimmu.2020.00753] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/02/2020] [Indexed: 12/15/2022] Open
Abstract
Cytotoxic lymphocytes, including natural killer (NK) cells and T cells are distinguished by their ability to eliminate target cells through release of secretory lysosomes. Conventional lysosomes and secretory lysosomes are part of the pleomorphic endolysosomal system and characterized by its highly dynamic nature. Several calcium-permeable TRP calcium channels play an essential role in endolysosomal calcium signaling to ensure proper function of these organelles. In NK cells, the expression of self MHC-specific inhibitory receptors dynamically tunes their secretory potential in a non-transcriptional, calcium-dependent manner. New insights suggest that TRPML1-mediated lysosomal calcium fluxes are tightly interconnected to NK cell functionality through modulation of granzyme B and perforin content of the secretory lysosome. Lysosomal TRP channels show a subset-specific expression pattern during NK differentiation, which is paralleled with gradually increased loading of effector molecules in secretory lysosomes. Methodological advances, including organellar patch-clamping, specific pharmacological modulators, and genetically-encoded calcium indicators open up new possibilities to investigate how TRP channels influence communication between intracellular organelles in immune cells. This review discusses our current understanding of lysosome biogenesis in NK cells with an emphasis on the TRP mucolipin family and the implications for NK cell functionality and cancer immunotherapy.
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Affiliation(s)
- Dennis Clement
- The KG Jebsen Center for Cancer Immunotherapy, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Cancer Immunology, Oslo University Hospital, Institute for Cancer Research, Oslo, Norway
| | | | - Christian Grimm
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Karl-Johan Malmberg
- The KG Jebsen Center for Cancer Immunotherapy, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Cancer Immunology, Oslo University Hospital, Institute for Cancer Research, Oslo, Norway
- Department of Medicine Huddinge, Center for Infectious Medicine, Karolinska Institutet, Stockholm, Sweden
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16
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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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17
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Bhat OM, Yuan X, Camus S, Salloum FN, Li PL. Abnormal Lysosomal Positioning and Small Extracellular Vesicle Secretion in Arterial Stiffening and Calcification of Mice Lacking Mucolipin 1 Gene. Int J Mol Sci 2020; 21:E1713. [PMID: 32138242 PMCID: PMC7084670 DOI: 10.3390/ijms21051713] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/24/2020] [Accepted: 02/28/2020] [Indexed: 12/14/2022] Open
Abstract
Recent studies have shown that arterial medial calcification is mediated by abnormal release of exosomes/small extracellular vesicles from vascular smooth muscle cells (VSMCs) and that small extracellular vesicle (sEV) secretion from cells is associated with lysosome activity. The present study was designed to investigate whether lysosomal expression of mucolipin-1, a product of the mouse Mcoln1 gene, contributes to lysosomal positioning and sEV secretion, thereby leading to arterial medial calcification (AMC) and stiffening. In Mcoln1-/- mice, we found that a high dose of vitamin D (Vit D; 500,000 IU/kg/day) resulted in increased AMC compared to their wild-type littermates, which was accompanied by significant downregulation of SM22-α and upregulation of RUNX2 and osteopontin in the arterial media, indicating a phenotypic switch to osteogenic. It was also shown that significantly decreased co-localization of lysosome marker (Lamp-1) with lysosome coupling marker (Rab 7 and ALG-2) in the aortic wall of Mcoln1-/- mice as compared to their wild-type littermates. Besides, Mcoln1-/- mice showed significant increase in the expression of exosome/ sEV markers, CD63, and annexin-II (AnX2) in the arterial medial wall, accompanied by significantly reduced co-localization of lysosome marker (Lamp-1) with multivesicular body (MVB) marker (VPS16), suggesting a reduction of the lysosome-MVB interactions. In the plasma of Mcoln1-/- mice, the number of sEVs significantly increased as compared to the wild-type littermates. Functionally, pulse wave velocity (PWV), an arterial stiffening indicator, was found significantly increased in Mcoln1-/- mice, and Vit D treatment further enhanced such stiffening. All these data indicate that the Mcoln1 gene deletion in mice leads to abnormal lysosome positioning and increased sEV secretion, which may contribute to the arterial stiffness during the development of AMC.
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Affiliation(s)
- Owais M. Bhat
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; (O.M.B.); (X.Y.); (S.C.)
| | - Xinxu Yuan
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; (O.M.B.); (X.Y.); (S.C.)
| | - Sarah Camus
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; (O.M.B.); (X.Y.); (S.C.)
| | - Fadi N. Salloum
- VCU Pauley Heart Center, Division of Cardiology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298-0204, USA;
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; (O.M.B.); (X.Y.); (S.C.)
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18
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Mahtani T, Treanor B. Beyond the CRAC: Diversification of ion signaling in B cells. Immunol Rev 2020; 291:104-122. [PMID: 31402507 PMCID: PMC6851625 DOI: 10.1111/imr.12770] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 04/30/2019] [Indexed: 12/22/2022]
Abstract
Although calcium signaling and the important role of calcium release–activated calcium channels is well recognized in the context of immune cell signaling, there is a vast diversity of ion channels and transporters that regulate the entry of ions beyond calcium, including magnesium, zinc, potassium, sodium, and chloride. These ions play a critical role in numerous metabolic and cellular processes. The importance of ions in human health and disease is illustrated by the identification of primary immunodeficiencies in patients with mutations in genes encoding ion channels and transporters, as well as the immunological defects observed in individuals with nutritional ion deficiencies. Despite progress in identifying the important role of ions in immune cell development and activation, we are still in the early stages of exploring the diversity of ion channels and transporters and mechanistically understanding the role of these ions in immune cell biology. Here, we review the biology of ion signaling in B cells and the identification of critical ion channels and transporters in B‐cell development, activation, and differentiation into effector cells. Elucidating the role of ion channels and transporters in immune cell signaling is critical for expanding the repertoire of potential therapeutics for the treatment of immune disorders. Moreover, increased understanding of the role of ions in immune cell function will enhance our understanding of the potentially serious consequences of ion deficiencies in human health and disease.
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Affiliation(s)
- Trisha Mahtani
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Bebhinn Treanor
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada.,Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario, Canada
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19
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Kasitinon SY, Eskiocak U, Martin M, Bezwada D, Khivansara V, Tasdogan A, Zhao Z, Mathews T, Aurora AB, Morrison SJ. TRPML1 Promotes Protein Homeostasis in Melanoma Cells by Negatively Regulating MAPK and mTORC1 Signaling. Cell Rep 2019; 28:2293-2305.e9. [PMID: 31461647 PMCID: PMC6813770 DOI: 10.1016/j.celrep.2019.07.086] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/01/2019] [Accepted: 07/23/2019] [Indexed: 12/14/2022] Open
Abstract
We screen ion channels and transporters throughout the genome to identify those required by human melanoma cells but not by normal human melanocytes. We discover that Mucolipin-1 (MCOLN1), which encodes the lysosomal cation channel TRPML1, is preferentially required for the survival and proliferation of melanoma cells. Loss of MCOLN1/TRPML1 function impairs the growth of patient-derived melanomas in culture and in xenografts but does not affect the growth of human melanocytes. TRPML1 expression and macropinocytosis are elevated in melanoma cells relative to melanocytes. TRPML1 is required in melanoma cells to negatively regulate MAPK pathway and mTORC1 signaling. TRPML1-deficient melanoma cells exhibit decreased survival, proliferation, tumor growth, and macropinocytosis, as well as serine depletion and proteotoxic stress. All of these phenotypes are partially or completely rescued by mTORC1 inhibition. Melanoma cells thus increase TRPML1 expression relative to melanocytes to attenuate MAPK and mTORC1 signaling, to sustain macropinocytosis, and to avoid proteotoxic stress.
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Affiliation(s)
- Stacy Y Kasitinon
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ugur Eskiocak
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Misty Martin
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Divya Bezwada
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Vishal Khivansara
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Alpaslan Tasdogan
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zhiyu Zhao
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Thomas Mathews
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Arin B Aurora
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sean J Morrison
- Children's Research Institute and Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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20
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BK channels regulate extracellular Tat-mediated HIV-1 LTR transactivation. Sci Rep 2019; 9:12285. [PMID: 31439883 PMCID: PMC6706582 DOI: 10.1038/s41598-019-48777-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 08/05/2019] [Indexed: 01/22/2023] Open
Abstract
HIV-1 Tat is essential for HIV-1 replication and plays an important role in latent HIV-1 infection, HIV-1 associated neurological complication, and other HIV-1 comorbidities. Secreted from HIV-1 infected or transfected cells, Tat can be up-taken into cells by receptor-mediated endocytosis and internalized into endolysosomes. To reach nucleus where it can facilitate HIV-1 viral replication, exogenous Tat has to escape the degradation by endolysosomes. Because of findings that endolysosome de-acidification with, for example, the weak-base anti-malarial drug chloroquine prevents exogenous Tat degradation and enhances the amount of Tat available to activate HIV-1 LTR, we hypothesize that acidifying endolysosomes may enhance Tat degradation in endolysosomes and restrict LTR transactivation. Here, we determined the involvement of endolysosome-resident transient receptor potential mucolipin 1 channel (TRPML1) and the big conductance Ca2+-activated potassium (BK) channel in regulating endolysosome pH, as well as Tat-mediated HIV-1 LTR transactivation in U87MG cells stably integrated with HIV-1 LTR luciferase reporter. Activating TRPML1 channels with ML-SA1 acidified endolysosomes and restricted Tat-mediated HIV-1 LTR transactivation. These effects of ML-SA1 appeared to be mediated through activation of BK channels, because the effects of ML-SA1 on Tat-mediated HIV-1 LTR transactivation were blocked using pharmacological inhibitors or shRNA knock-down of BK channels. On the other hand, activating TRPML1 and BK channels enhanced cellular degradation of exogenous Tat. These results suggest that acidifying endolysosomes by activating TRPML1 or BK channels may provide therapeutic benefit against latent HIV-1 infection, HIV-1 associated neurocognitive disorders, and other HIV-1 comorbidities.
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21
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Yang Y, Xu M, Zhu X, Yao J, Shen B, Dong XP. Lysosomal Ca 2+ release channel TRPML1 regulates lysosome size by promoting mTORC1 activity. Eur J Cell Biol 2019; 98:116-123. [PMID: 31122790 DOI: 10.1016/j.ejcb.2019.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 04/10/2019] [Accepted: 05/13/2019] [Indexed: 12/22/2022] Open
Abstract
Lysosomal Ca2+ release channel TRPML1 has been suggested to regulate lysosome size by activating calmodulin (CaM). To further understand how TRPML1 and CaM regulate lysosome size, in this study, we report that inhibiting mTORC1 causes enlarged lysosomes, and the recovery of enlarged lysosomes is suppressed by inhibiting mTORC1. We also show that lysosome vacuolation induced by inhibiting TRPML1 is corrected by mTORC1 upregulation, and the facilitating effect of TRPML1 on the recovery of enlarged lysosomes is suppressed by inhibiting mTORC1. In the meantime, lysosome vacuolation induced by inhibiting CaM is corrected by mTORC1 upregulation, and mTORC1 overexpression corrects the inhibitory effect of CaM antagonist on the recovery of enlarged lysosomes. Conversely, the vacuolation induced by suppressing mTORC1 is not corrected by upregulating CaM. These data suggest that mTORC1 functions downstream of TRPML1 and CaM to regulate lysosome size. Together with our recent finding showing that TRPML1, CaM and mTORC1 form a macromolecular complex to control mTORC1 activity, we suggest that TRPML1 and CaM control lysosome fission through regulating mTORC1, identifying an mTORC1-dependent molecular mechanism for lysosomal membrane fission.
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Affiliation(s)
- Yiming Yang
- Department of Physiology and Biophysics, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, B3H 4R2, Nova Scotia, Canada; Key Laboratory of Molecular Epigenetics, Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, 130021, China
| | - Mengnan Xu
- Department of Physiology and Biophysics, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, B3H 4R2, Nova Scotia, Canada; Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei,230032, China
| | - Xiaojuan Zhu
- Key Laboratory of Molecular Epigenetics, Ministry of Education, Institute of Genetics and Cytology, Northeast Normal University, Changchun, 130021, China
| | - Jing Yao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Bing Shen
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei,230032, China
| | - Xian-Ping Dong
- Department of Physiology and Biophysics, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, B3H 4R2, Nova Scotia, Canada; Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei,230032, China.
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22
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Jin W, Dai Y, Li F, Zhu L, Huang Z, Liu W, Li J, Zhang M, Du J, Zhang W, Wen Z. Dysregulation of Microglial Function Contributes to Neuronal Impairment in Mcoln1a-Deficient Zebrafish. iScience 2019; 13:391-401. [PMID: 30897512 PMCID: PMC6426713 DOI: 10.1016/j.isci.2019.02.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/28/2018] [Accepted: 02/26/2019] [Indexed: 01/21/2023] Open
Abstract
Type IV mucolipidosis (ML-IV) is a neurodegenerative lysosome storage disorder caused by mutations in the MCOLN1 gene. However, the cellular and molecular bases underlying the neuronal phenotypes of ML-IV disease remain elusive. Using a forward genetic screening, we identified a zebrafish mutant, biluo, that harbors a hypomorphic mutation in mcoln1a, one of the two zebrafish homologs of mammalian MCOLN1. The mcoln1a-deficient mutants display phenotypes partially recapitulating the key features of ML-IV disorder, including the accumulation of enlarged late endosomes in microglia and aberrant neuronal activities in both spontaneous and visual-evoking conditions in optic tectal neurons. We further show that the accumulation of enlarged late endosomes in microglia is caused by the impairment of late endosome and lysosome fusion and the aberrant neuronal activities can be partially rescued by the reconstitution of Mcoln1a function in microglia. Our findings suggest that dysregulation of microglial function may contribute to the development and progression of ML-IV disease. mcoln1a-deficient fish display microglia impairment and aberrant neuronal activity The aberrant neuronal activity can be rescued by expressing WT mcoln1a in microglia Impairment of microglia-neuron contact contributes to the aberrant neuronal activity
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Affiliation(s)
- Wan Jin
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR. China
| | - Yimei Dai
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR. China
| | - Funing Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, PR. China
| | - Lu Zhu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR. China
| | - Zhibin Huang
- Department of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, PR. China
| | - Wei Liu
- Department of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, PR. China
| | - Jianchao Li
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR. China
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR. China
| | - Jiulin Du
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, PR. China
| | - Wenqing Zhang
- Department of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, PR. China.
| | - Zilong Wen
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR. China; Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, PR. China.
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23
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Kheradpezhouh E, Zhou FH, Barritt GJ, Rychkov GY. Oxidative stress promotes redistribution of TRPM2 channels to the plasma membrane in hepatocytes. Biochem Biophys Res Commun 2018; 503:1891-1896. [PMID: 30075844 DOI: 10.1016/j.bbrc.2018.07.132] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 07/25/2018] [Indexed: 10/28/2022]
Abstract
Transient Receptor Potential Melastatin (TRPM) 2 is a non-selective Ca2+ permeable cation channel and a member of the Transient Receptor Potential (TRP) channel family. TRPM2 has unique gating properties; it is activated by intracellular ADP-ribose (ADPR), whereas Ca2+ plays a role of an important co-factor in channel activation, increasing TRPM2 sensitivity to ADPR. TRPM2 is highly expressed in rat and mouse hepatocytes, where it has been shown to contribute to oxidative stress-induced cell death and liver damage due to paracetamol-overdose. The mechanisms regulating the activity of TRPM2 channels in hepatocytes, however, are not well understood. In this paper, we investigate the localisation of TRPM2 protein in hepatocytes. The presented results demonstrate that in rat hepatocytes under normal conditions, most of the TRPM2 protein is localised intracellularly. This was determined by confocal microscopy using TRPM2-and plasma membrane (PM)-specific antibodies and immunofluorescence, and biotinylation studies followed by western blotting. Interestingly, in hepatocytes treated with either H2O2 or paracetamol, the amount of TRPM2 co-localised with PM is significantly increased, compared to the untreated cells. It is concluded that trafficking of TRPM2 to the PM could potentially contribute to a positive feedback mechanism mediating Ca2+ overload in hepatocytes under conditions of oxidative stress.
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Affiliation(s)
- Ehsan Kheradpezhouh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Acton, ACT, 2601, Australia; The Australian Research Council Centre of Excellence for Integrative Brain Research, Australian National University Node, Acton, ACT, 2601, Australia; School of Medicine, The University of Adelaide, Adelaide, 5005, SA, Australia.
| | - Fiona H Zhou
- School of Medicine, The University of Adelaide, Adelaide, 5005, SA, Australia; South Australian Health and Medical Research Institute (SAHMRI), Adelaide, 5005, SA, Australia
| | - Greg J Barritt
- Discipline of Medical Biochemistry, College of Medicine and Public Health, Flinders University, Adelaide, SA, 5001, Australia
| | - Grigori Y Rychkov
- School of Medicine, The University of Adelaide, Adelaide, 5005, SA, Australia; South Australian Health and Medical Research Institute (SAHMRI), Adelaide, 5005, SA, Australia.
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Kanie Y, Taniuchi M, Kanie O. Evaluation of reversed-phase nano liquid chromatography conditions by using reversed-phase thin layer chromatography based on Hansen solubility parameters for the analysis of amphiphilic glycosylsphingolipid transformations. J Chromatogr A 2018; 1534:123-129. [PMID: 29290400 DOI: 10.1016/j.chroma.2017.12.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/20/2017] [Accepted: 12/21/2017] [Indexed: 11/30/2022]
Abstract
Pulse chase analysis is often used in investigating dynamics of cellular substances. Fluorescently labeled lactosyl sphingosine molecule is useful in chasing its transformation, however the analysis of such metabolites in attomole level is of extreme difficult due to the presence of large amount of endogenous amphiphilic molecules such as glycosphingolipids, sphingomyerin, and glycerophospholipids. Nano LC suites for analyzing the attomole scale metabolites, therefore removal of endogenous substances prior to nano LC and finding appropriate nano LC conditions are necessary. Thus, we focused on the solubility of fluorescent BODIPY-labeled lactosylsphingosine (Lac-Sph-BODIPY) to identify suitable solvents to remove endogenous compounds. In this study, we evaluated solvents by using C18 thin layer chromatography (RP TLC). The mobility (Rf) of Lac-Sph-BODIPY against several solvent mixtures on RP TLC were plotted against polarity and hydrogen bonding capability followed by Hansen solubility parameters (HSPs). The optimum solvent mixture with Rf = 0.3 ± 0.1 was chosen for elimination of endogenous phospholipids on a ZrO2-SiO2 cartridge column and subsequent separation by nano LC. Efficient removal of endogenous phospholipids was demonstrated, and good resolution in nano LC analysis of Lac-Sph-BODIPY extracted from Chinese hamster ovary (CHO)-K1 cells was achieved. It was also shown that the amount of exogenously added compound was important in the investigation of metabolites using cultured cells.
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Affiliation(s)
- Yoshimi Kanie
- Department of Applied Biochemistry, Tokai University, 4-1-1 Kitakaname, Hiratsuka, 259-1292 Kanagawa, Japan
| | - Mizuki Taniuchi
- Department of Applied Biochemistry, Tokai University, 4-1-1 Kitakaname, Hiratsuka, 259-1292 Kanagawa, Japan
| | - Osamu Kanie
- Department of Applied Biochemistry, Tokai University, 4-1-1 Kitakaname, Hiratsuka, 259-1292 Kanagawa, Japan.
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25
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Baksi S, Singh N. α-Synuclein impairs ferritinophagy in the retinal pigment epithelium: Implications for retinal iron dyshomeostasis in Parkinson's disease. Sci Rep 2017; 7:12843. [PMID: 28993630 PMCID: PMC5634503 DOI: 10.1038/s41598-017-12862-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 09/14/2017] [Indexed: 01/14/2023] Open
Abstract
Retinal degeneration is prominent in Parkinson’s disease (PD), a neuromotor disorder associated with aggregation of α-synuclein (α-syn) in the substantia-nigra (SN). Although α-syn is expressed in the neuroretina, absence of prominent aggregates suggests altered function as the likely cause of retinal pathology. We demonstrate that α-syn impairs ferritinophagy, resulting in the accumulation of iron-rich ferritin in the outer retina in-vivo and retinal-pigment-epithelial (RPE) cells in-vitro. Over-expression of Rab1a restores ferritinophagy, suggesting that α-syn impairs lysosomal function by disrupting the trafficking of lysosomal hydrolases. Surprisingly, upregulation of ferritin in RPE cells by exogenous iron in-vitro stimulated the release of ferritin and α-syn in exosomes, suggesting that iron overload due to impaired ferritinophagy or other cause(s) is likely to initiate prion-like spread of α-syn and ferritin, creating retinal iron dyshomeostasis and associated cytotoxicity. Since over-expression of α-syn is a known cause of PD, these results explain the likely cause of PD-associated retinal degeneration.
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Affiliation(s)
- Shounak Baksi
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, 44106, USA.
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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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27
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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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Tsuruta F, Okajima T, Yano S, Chiba T. Quantification of Endosome and Lysosome Motilities in Cultured Neurons Using Fluorescent Probes. J Vis Exp 2017. [PMID: 28570534 DOI: 10.3791/55488] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In the brain, membrane trafficking systems play important roles in regulating neuronal functions, such as neuronal morphology, synaptic plasticity, survival, and glial communications. To date, numerous studies have reported that defects in these systems cause various neuronal diseases. Thus, understanding the mechanisms underlying vesicle dynamics may provide influential clues that could aid in the treatment of several neuronal disorders. Here, we describe a method for quantifying vesicle motilities, such as motility distance and rate of movement, using a software plug-in for the ImageJ platform. To obtain images for quantification, we labeled neuronal endosome-lysosome structures with EGFP-tagged vesicle marker proteins and observed the movement of vesicles using a time-lapse microscopy. This method is highly useful and simplify measuring vesicle motility in neurites, such as axons and dendrites, as well as in the soma of both neurons and glial cells. Furthermore, this method can be applied to other cell lines, such as fibroblasts and endothelial cells. This approach could provide a valuable advancement of our understanding of membrane trafficking.
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Affiliation(s)
- Fuminori Tsuruta
- Graduate School of Life and Environmental Sciences, University of Tsukuba; PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba; Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba;
| | - Tomomi Okajima
- Graduate School of Life and Environmental Sciences, University of Tsukuba
| | - Sarasa Yano
- Graduate School of Life and Environmental Sciences, University of Tsukuba
| | - Tomoki Chiba
- Graduate School of Life and Environmental Sciences, University of Tsukuba; PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba; Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba
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29
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Slade L, Cowie A, Martyniuk CJ, Kienesberger PC, Pulinilkunnil T. Dieldrin Augments mTOR Signaling and Regulates Genes Associated with Cardiovascular Disease in the Adult Zebrafish Heart (Danio rerio). J Pharmacol Exp Ther 2017; 361:375-385. [DOI: 10.1124/jpet.116.239806] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 04/05/2017] [Indexed: 11/22/2022] Open
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Cao Q, Yang Y, Zhong XZ, Dong XP. The lysosomal Ca 2+ release channel TRPML1 regulates lysosome size by activating calmodulin. J Biol Chem 2017; 292:8424-8435. [PMID: 28360104 DOI: 10.1074/jbc.m116.772160] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/29/2017] [Indexed: 01/01/2023] Open
Abstract
Intracellular lysosomal membrane trafficking, including fusion and fission, is crucial for cellular homeostasis and normal cell function. Both fusion and fission of lysosomal membrane are accompanied by lysosomal Ca2+ release. We recently have demonstrated that the lysosomal Ca2+ release channel P2X4 regulates lysosome fusion through a calmodulin (CaM)-dependent mechanism. However, the molecular mechanism underlying lysosome fission remains uncertain. In this study, we report that enlarged lysosomes/vacuoles induced by either vacuolin-1 or P2X4 activation are suppressed by up-regulating the lysosomal Ca2+ release channel transient receptor potential mucolipin 1 (TRPML1) but not the lysosomal Na+ release channel two-pore channel 2 (TPC2). Activation of TRPML1 facilitated the recovery of enlarged lysosomes/vacuoles. Moreover, the effects of TRPML1 on lysosome/vacuole size regulation were eliminated by Ca2+ chelation, suggesting a requirement for TRPML1-mediated Ca2+ release. We further demonstrate that the prototypical Ca2+ sensor CaM is required for the regulation of lysosome/vacuole size by TRPML1, suggesting that TRPML1 may promote lysosome fission by activating CaM. Given that lysosome fission is implicated in both lysosome biogenesis and reformation, our findings suggest that TRPML1 may function as a key lysosomal Ca2+ channel controlling both lysosome biogenesis and reformation.
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Affiliation(s)
- Qi Cao
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Yiming Yang
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xi Zoë Zhong
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xian-Ping Dong
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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31
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Erkhembaatar M, Gu DR, Lee SH, Yang YM, Park S, Muallem S, Shin DM, Kim MS. Lysosomal Ca 2+ Signaling is Essential for Osteoclastogenesis and Bone Remodeling. J Bone Miner Res 2017; 32:385-396. [PMID: 27589205 PMCID: PMC9850942 DOI: 10.1002/jbmr.2986] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/29/2016] [Accepted: 08/31/2016] [Indexed: 01/21/2023]
Abstract
Lysosomal Ca2+ emerges as a critical component of receptor-evoked Ca2+ signaling and plays a crucial role in many lysosomal and physiological functions. Lysosomal Ca2+ release is mediated by the transient receptor potential (TRP) family member TRPML1, mutations that cause the lysosomal storage disease mucolipidosis type 4. Lysosomes play a key role in osteoclast function. However, nothing is known about the role of lysosomal Ca2+ signaling in osteoclastogenesis and bone metabolism. In this study, we addressed this knowledge gap by studying the role of lysosomal Ca2+ signaling in osteoclastogenesis, osteoclast and osteoblast functions, and bone homeostasis in vivo. We manipulated lysosomal Ca2+ signaling by acute knockdown of TRPML1, deletion of TRPML1 in mice, pharmacological inhibition of lysosomal Ca2+ influx, and depletion of lysosomal Ca2+ storage using the TRPML agonist ML-SA1. We found that knockdown and deletion of TRPML1, although it did not have an apparent effect on osteoblast differentiation and bone formation, markedly attenuated osteoclast function, RANKL-induced cytosolic Ca2+ oscillations, inhibited activation of NFATc1 and osteoclastogenesis-controlling genes, suppressed the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs), and markedly reduced the differentiation of bone marrow-derived macrophages into osteoclasts. Moreover, deletion of TRPML1 resulted in enlarged lysosomes, inhibition of lysosomal secretion, and attenuated the resorptive activity of mature osteoclasts. Notably, depletion of lysosomal Ca2+ with ML-SA1 similarly abrogated RANKL-induced Ca2+ oscillations and MNC formation. Deletion of TRPML1 in mice reduced the TRAP-positive bone surfaces and impaired bone remodeling, resulting in prominent osteopetrosis. These findings demonstrate the essential role of lysosomal Ca2+ signaling in osteoclast differentiation and mature osteoclast function, which play key roles in bone homeostasis. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Munkhsoyol Erkhembaatar
- Department of Oral Physiology, and Institute of Biomaterial-Implant, College of Dentistry, Wonkwang University, Iksan, Republic of Korea.,Department of Physiology, School of Pharmacy and Bio-Medicine, Mongolian National University of Medical Science, Ulaanbaatar, Mongolia
| | - Dong Ryun Gu
- Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Republic of Korea.,Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Republic of Korea
| | - Seoung Hoon Lee
- Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Republic of Korea.,Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Republic of Korea
| | - Yu-Mi Yang
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Soonhong Park
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Dong Min Shin
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Min Seuk Kim
- Department of Oral Physiology, and Institute of Biomaterial-Implant, College of Dentistry, Wonkwang University, Iksan, Republic of Korea
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32
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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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Determining the Turnover of Glycosphingolipid Species by Stable-Isotope Tracer Lipidomics. J Mol Biol 2016; 428:4856-4866. [PMID: 27363608 DOI: 10.1016/j.jmb.2016.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/16/2016] [Accepted: 06/17/2016] [Indexed: 01/08/2023]
Abstract
In this study, we used water-soluble stable mass isotope precursors to measure the turnover of endogenous ceramide (Cer) and glycosphingolipids (GSLs) in HEp-2 cells. Cells incubated in the presence of [13C-U]glucose showed rapid incorporation of hexose residues with an increased mass of 6Da into GSLs. Different turnover rates of GSL classes and their molecular species were observed. Approximately 30% of the glucosylceramide, 50% of the lactosylceramide, and 50% of the globotriaosylceramide species showed a much slower turnover than the rest. This demonstrates the existence of different lipid pools, where a certain fraction of species survived for a long time in the cells. The species with the shortest N-amidated fatty acyl groups (C16:0 and C18:0) showed a more rapid turnover than those with the longest N-amidated fatty acids (C24:0 and C24:1). Experiments with addition of [13C-U]serine were performed to study de novo synthesis of Cer from serine and palmitoyl-CoA. These experiments revealed that de novo synthesis contributes to a minor extent to the total synthesis of new sphingolipids and showed that there is a more rapid formation of the longest Cer species (C24:0 and C24:1) than of the shortest species (C16:0), that is, the opposite as observed for the GSLs in the experiments with [13C-U]glucose. In conclusion, this FLUX lipidomics experimental approach with the addition of [13C-U]glucose to cells allows us to not only study the total turnover but also permit observations of lipid intermediates and metabolic flow of endogenous GSL species at the molecular lipid level.
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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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35
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A molecular mechanism to regulate lysosome motility for lysosome positioning and tubulation. Nat Cell Biol 2016; 18:404-17. [PMID: 26950892 PMCID: PMC4871318 DOI: 10.1038/ncb3324] [Citation(s) in RCA: 283] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/04/2016] [Indexed: 12/12/2022]
Abstract
To mediate the degradation of bio-macromolecules, lysosomes must traffic towards cargo-carrying vesicles for subsequent membrane fusion or fission. Mutations of the lysosomal Ca2+ channel TRPML1 cause lysosome storage disease (LSD) characterized by disordered lysosomal membrane trafficking in cells. Here we show that TRPML1 activity is required to promote Ca2+-dependent centripetal movement of lysosomes towards the perinuclear region, where autophagosomes accumulate, upon autophagy induction. ALG-2, an EF-hand-containing protein, serves as a lysosomal Ca2+ sensor that associates physically with the minus-end directed dynactin-dynein motor, while PI(3,5)P2, a lysosome-localized phosphoinositide, acts upstream of TRPML1. Furthermore, the PI(3,5)P2-TRPML1-ALG-2-dynein signaling is necessary for lysosome tubulation and reformation. In contrast, the TRPML1 pathway is not required for the perinuclear accumulation of lysosomes observed in many LSDs, which is instead likely caused by secondary cholesterol accumulation that constitutively activates Rab7-RILP-dependent retrograde transport. Collectively, Ca2+ release from lysosomes provides an on-demand mechanism regulating lysosome motility, positioning, and tubulation.
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36
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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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Park S, Ahuja M, Kim MS, Brailoiu GC, Jha A, Zeng M, Baydyuk M, Wu LG, Wassif CA, Porter FD, Zerfas PM, Eckhaus MA, Brailoiu E, Shin DM, Muallem S. Fusion of lysosomes with secretory organelles leads to uncontrolled exocytosis in the lysosomal storage disease mucolipidosis type IV. EMBO Rep 2015; 17:266-78. [PMID: 26682800 DOI: 10.15252/embr.201541542] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/04/2015] [Indexed: 01/29/2023] Open
Abstract
Mutations in TRPML1 cause the lysosomal storage disease mucolipidosis type IV (MLIV). The role of TRPML1 in cell function and how the mutations cause the disease are not well understood. Most studies focus on the role of TRPML1 in constitutive membrane trafficking to and from the lysosomes. However, this cannot explain impaired neuromuscular and secretory cells' functions that mediate regulated exocytosis. Here, we analyzed several forms of regulated exocytosis in a mouse model of MLIV and, opposite to expectations, we found enhanced exocytosis in secretory glands due to enlargement of secretory granules in part due to fusion with lysosomes. Preliminary exploration of synaptic vesicle size, spontaneous mEPSCs, and glutamate secretion in neurons provided further evidence for enhanced exocytosis that was rescued by re-expression of TRPML1 in neurons. These features were not observed in Niemann-Pick type C1. These findings suggest that TRPML1 may guard against pathological fusion of lysosomes with secretory organelles and suggest a new approach toward developing treatment for MLIV.
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Affiliation(s)
- Soonhong Park
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Min Seuk Kim
- Department of Oral Physiology, School of Dentistry, Wonkwang University, Iksan City, Korea
| | - G Cristina Brailoiu
- Department of Pharmaceutical Sciences, Jefferson School of Pharmacy, Thomas Jefferson University, Philadelphia, PA, USA
| | - Archana Jha
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Mei Zeng
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Maryna Baydyuk
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Christopher A Wassif
- Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Forbes D Porter
- Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Patricia M Zerfas
- Diagnostic and Research Services Branch, Division of Veterinary Resources, Office of Research Services, National Institutes of Health, Bethesda, MD, USA
| | - Michael A Eckhaus
- Diagnostic and Research Services Branch, Division of Veterinary Resources, Office of Research Services, National Institutes of Health, Bethesda, MD, USA
| | - Eugen Brailoiu
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA, USA
| | - Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
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Grishchuk Y, Stember KG, Matsunaga A, Olivares AM, Cruz NM, King VE, Humphrey DM, Wang SL, Muzikansky A, Betensky RA, Thoreson WB, Haider N, Slaugenhaupt SA. Retinal Dystrophy and Optic Nerve Pathology in the Mouse Model of Mucolipidosis IV. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 186:199-209. [PMID: 26608452 DOI: 10.1016/j.ajpath.2015.09.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 08/31/2015] [Accepted: 09/10/2015] [Indexed: 11/19/2022]
Abstract
Mucolipidosis IV is a debilitating developmental lysosomal storage disorder characterized by severe neuromotor retardation and progressive loss of vision, leading to blindness by the second decade of life. Mucolipidosis IV is caused by loss-of-function mutations in the MCOLN1 gene, which encodes the transient receptor potential channel protein mucolipin-1. Ophthalmic pathology in patients includes corneal haze and progressive retinal and optic nerve atrophy. Herein, we report ocular pathology in Mcoln1(-/-) mouse, a good phenotypic model of the disease. Early, but non-progressive, thinning of the photoreceptor layer, reduced levels of rhodopsin, disrupted rod outer segments, and widespread accumulation of the typical storage inclusion bodies were the major histological findings in the Mcoln1(-/-) retina. Electroretinograms showed significantly decreased functional response (scotopic a- and b-wave amplitudes) in the Mcoln1(-/-) mice. At the ultrastructural level, we observed formation of axonal spheroids and decreased density of axons in the optic nerve of the aged (6-month-old) Mcoln1(-/-) mice, which indicates progressive axonal degeneration. Our data suggest that mucolipin-1 plays a role in postnatal development of photoreceptors and provides a set of outcome measures that can be used for ocular therapy development for mucolipidosis IV.
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Affiliation(s)
- Yulia Grishchuk
- Department of Neurology, Center for Human Genetic Research, Harvard Medical School, Boston, Massachusetts.
| | - Katherine G Stember
- Department of Neurology, Center for Human Genetic Research, Harvard Medical School, Boston, Massachusetts
| | - Aya Matsunaga
- Department of Neurology, Center for Human Genetic Research, Harvard Medical School, Boston, Massachusetts
| | - Ana M Olivares
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Nelly M Cruz
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Victoria E King
- Department of Neurology, Center for Human Genetic Research, Harvard Medical School, Boston, Massachusetts
| | - Daniel M Humphrey
- Department of Neurology, Center for Human Genetic Research, Harvard Medical School, Boston, Massachusetts
| | - Shirley L Wang
- Department of Neurology, Center for Human Genetic Research, Harvard Medical School, Boston, Massachusetts
| | - Alona Muzikansky
- Massachusetts General Hospital Biostatistics Center, Massachusetts General Hospital, Boston, Massachusetts
| | - Rebecca A Betensky
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts
| | - Wallace B Thoreson
- Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, Nebraska
| | - Neena Haider
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Susan A Slaugenhaupt
- Department of Neurology, Center for Human Genetic Research, Harvard Medical School, Boston, Massachusetts
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39
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Abstract
Lysosomes are acidic compartments filled with more than 60 different types of hydrolases. They mediate the degradation of extracellular particles from endocytosis and of intracellular components from autophagy. The digested products are transported out of the lysosome via specific catabolite exporters or via vesicular membrane trafficking. Lysosomes also contain more than 50 membrane proteins and are equipped with the machinery to sense nutrient availability, which determines the distribution, number, size, and activity of lysosomes to control the specificity of cargo flux and timing (the initiation and termination) of degradation. Defects in degradation, export, or trafficking result in lysosomal dysfunction and lysosomal storage diseases (LSDs). Lysosomal channels and transporters mediate ion flux across perimeter membranes to regulate lysosomal ion homeostasis, membrane potential, catabolite export, membrane trafficking, and nutrient sensing. Dysregulation of lysosomal channels underlies the pathogenesis of many LSDs and possibly that of metabolic and common neurodegenerative diseases.
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Affiliation(s)
- Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109;
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40
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Sun N, Yun J, Liu J, Malide D, Liu C, Rovira II, Holmström KM, Fergusson MM, Yoo YH, Combs CA, Finkel T. Measuring In Vivo Mitophagy. Mol Cell 2015; 60:685-96. [PMID: 26549682 DOI: 10.1016/j.molcel.2015.10.009] [Citation(s) in RCA: 476] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 08/27/2015] [Accepted: 10/02/2015] [Indexed: 01/05/2023]
Abstract
Alterations in mitophagy have been increasingly linked to aging and age-related diseases. There are, however, no convenient methods to analyze mitophagy in vivo. Here, we describe a transgenic mouse model in which we expressed a mitochondrial-targeted form of the fluorescent reporter Keima (mt-Keima). Keima is a coral-derived protein that exhibits both pH-dependent excitation and resistance to lysosomal proteases. Comparison of a wide range of primary cells and tissues generated from the mt-Keima mouse revealed significant variations in basal mitophagy. In addition, we have employed the mt-Keima mice to analyze how mitophagy is altered by conditions including diet, oxygen availability, Huntingtin transgene expression, the absence of macroautophagy (ATG5 or ATG7 expression), an increase in mitochondrial mutational load, the presence of metastatic tumors, and normal aging. The ability to assess mitophagy under a host of varying environmental and genetic perturbations suggests that the mt-Keima mouse should be a valuable resource.
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Affiliation(s)
- Nuo Sun
- Center for Molecular Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Jeanho Yun
- Center for Molecular Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA; Mitochondria Hub Regulation Center, College of Medicine, Dong-A University, Busan 602-714, Republic of Korea
| | - Jie Liu
- Center for Molecular Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Daniela Malide
- Light Microscopy Core, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Chengyu Liu
- Transgenic Core, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Ilsa I Rovira
- Center for Molecular Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Kira M Holmström
- Center for Molecular Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Maria M Fergusson
- Center for Molecular Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Young Hyun Yoo
- Mitochondria Hub Regulation Center, College of Medicine, Dong-A University, Busan 602-714, Republic of Korea
| | - Christian A Combs
- Light Microscopy Core, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Toren Finkel
- Center for Molecular Medicine, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA.
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Abstract
Eukaryotic cells have been confronted throughout their evolution with potentially lethal plasma membrane injuries, including those caused by osmotic stress, by infection from bacterial toxins and parasites, and by mechanical and ischemic stress. The wounded cell can survive if a rapid repair response is mounted that restores boundary integrity. Calcium has been identified as the key trigger to activate an effective membrane repair response that utilizes exocytosis and endocytosis to repair a membrane tear, or remove a membrane pore. We here review what is known about the cellular and molecular mechanisms of membrane repair, with particular emphasis on the relevance of repair as it relates to disease pathologies. Collective evidence reveals membrane repair employs primitive yet robust molecular machinery, such as vesicle fusion and contractile rings, processes evolutionarily honed for simplicity and success. Yet to be fully understood is whether core membrane repair machinery exists in all cells, or whether evolutionary adaptation has resulted in multiple compensatory repair pathways that specialize in different tissues and cells within our body.
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Affiliation(s)
- Sandra T Cooper
- Institute for Neuroscience and Muscle Research, Kids Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia; Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia; and Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, Georgia
| | - Paul L McNeil
- Institute for Neuroscience and Muscle Research, Kids Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia; Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia; and Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, Georgia
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Cao Q, Zhong XZ, Zou Y, Murrell-Lagnado R, Zhu MX, Dong XP. Calcium release through P2X4 activates calmodulin to promote endolysosomal membrane fusion. J Cell Biol 2015; 209:879-94. [PMID: 26101220 PMCID: PMC4477861 DOI: 10.1083/jcb.201409071] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
P2X4 and calmodulin form a signaling complex in late endosomes and lysosomes that promotes fusion and vacuolation in a Ca2+-dependent fashion. Intra-endolysosomal Ca2+ release is required for endolysosomal membrane fusion with intracellular organelles. However, the molecular mechanisms for intra-endolysosomal Ca2+ release and the downstream Ca2+ targets involved in the fusion remain elusive. Previously, we demonstrated that endolysosomal P2X4 forms channels activated by luminal adenosine triphosphate in a pH-dependent manner. In this paper, we show that overexpression of P2X4, as well as increasing endolysosomal P2X4 activity by alkalinization of endolysosome lumen, promoted vacuole enlargement in cells and endolysosome fusion in a cell-free assay. These effects were prevented by inhibiting P2X4, expressing a dominant-negative P2X4 mutant, and disrupting the P2X4 gene. We further show that P2X4 and calmodulin (CaM) form a complex at endolysosomal membrane where P2X4 activation recruits CaM to promote fusion and vacuolation in a Ca2+-dependent fashion. Moreover, P2X4 activation-triggered fusion and vacuolation were suppressed by inhibiting CaM. Our data thus suggest a new molecular mechanism for endolysosomal membrane fusion involving P2X4-mediated endolysosomal Ca2+ release and subsequent CaM activation.
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Affiliation(s)
- Qi Cao
- Department of Physiology and Biophysics, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
| | - Xi Zoë Zhong
- Department of Physiology and Biophysics, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
| | - Yuanjie Zou
- Department of Physiology and Biophysics, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
| | - Ruth Murrell-Lagnado
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, England, UK
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Xian-Ping Dong
- Department of Physiology and Biophysics, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
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Abstract
The exact mechanisms underlying the lysosomal storage disorder (LSD) mucolipidosis type IV (MLIV) are unclear. In the present study, we provide evidence that mTOR regulates the opening and closing of the lysosomal channel responsible for MLIV through phosphorylation. Autophagy is a complex pathway regulated by numerous signalling events that recycles macromolecules and may be perturbed in lysosomal storage disorders (LSDs). During autophagy, aberrant regulation of the lysosomal Ca2+ efflux channel TRPML1 [transient receptor potential mucolipin 1 (MCOLN1)], also known as MCOLN1, is solely responsible for the human LSD mucolipidosis type IV (MLIV); however, the exact mechanisms involved in the development of the pathology of this LSD are unknown. In the present study, we provide evidence that the target of rapamycin (TOR), a nutrient-sensitive protein kinase that negatively regulates autophagy, directly targets and inactivates the TRPML1 channel and thereby functional autophagy, through phosphorylation. Further, mutating these phosphorylation sites to unphosphorylatable residues proved to block TOR regulation of the TRPML1 channel. These findings suggest a mechanism for how TOR activity may regulate the TRPML1 channel.
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Mirabelli-Badenier M, Severino M, Tappino B, Tortora D, Camia F, Zanaboni C, Brera F, Priolo E, Rossi A, Biancheri R, Di Rocco M, Filocamo M. A novel homozygous MCOLN1 double mutant allele leading to TRP channel domain ablation underlies Mucolipidosis IV in an Italian Child. Metab Brain Dis 2015; 30:681-6. [PMID: 25156245 DOI: 10.1007/s11011-014-9612-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 08/15/2014] [Indexed: 10/24/2022]
Abstract
Mucolipidosis type IV (MLIV) is a very rare disorder of late endosome/lysosome transport, characterized by neurodevelopmental abnormalities and progressive visual impairment owing to corneal clouding and retinal dystrophy. Greater than 70 % of MLIV patients are of Ashkenazi Jewish ancestry. Here we report a novel MCOLN1double mutant allele [c.395_397delCTG;c.468_474dupTTGGACC] which introduces a premature stop codon [p.Ala132del; p.Asn159LeufsX27] leading to almost complete abrogation of the region coding mucolipin-1, a member of the transient receptor potential (TRP) cation channel family. The genomic lesion was identified in homozygous state, in a non-Jewish Italian MLIV patient, who also presented abnormal serum gastrin levels. Conventional and advanced MRI sequences, including diffusion tensor imaging and tractography, were used for the assessment of white matter involvement in the patient.
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Miller A, Schafer J, Upchurch C, Spooner E, Huynh J, Hernandez S, McLaughlin B, Oden L, Fares H. Mucolipidosis type IV protein TRPML1-dependent lysosome formation. Traffic 2015; 16:284-97. [PMID: 25491304 DOI: 10.1111/tra.12249] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 12/03/2014] [Accepted: 12/03/2014] [Indexed: 02/05/2023]
Abstract
Lysosomes are dynamic organelles that undergo cycles of fusion and fission with themselves and with other organelles. Following fusion with late endosomes to form hybrid organelles, lysosomes are reformed as discrete organelles. This lysosome reformation or formation is a poorly understood process that has not been systematically analyzed and that lacks known regulators. In this study, we quantitatively define the multiple steps of lysosome formation and identify the first regulator of this process.
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Affiliation(s)
- Austin Miller
- Department of Molecular and Cellular Biology, Life Sciences South Room 531, University of Arizona, Tucson, AZ, 85721, USA
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Cellular Localization and Trafficking of the Human ABCG1 Transporter. BIOLOGY 2014; 3:781-800. [PMID: 25405320 PMCID: PMC4280511 DOI: 10.3390/biology3040781] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 10/23/2014] [Accepted: 10/28/2014] [Indexed: 11/17/2022]
Abstract
We have developed a suitable heterologous cell expression system to study the localization, trafficking, and site(s) of function of the human ABCG1 transporter. Increased plasma membrane (PM) and late endosomal (LE) cholesterol generated by ABCG1 was removed by lipoproteins and liposomes, but not apoA-I. Delivery of ABCG1 to the PM and LE was required for ABCG1-mediated cellular cholesterol efflux. ABCG1 LEs frequently contacted the PM, providing a collisional mechanism for transfer of ABCG1-mobilized cholesterol, similar to ABCG1-mediated PM cholesterol efflux to lipoproteins. ABCG1-mobilized LE cholesterol also trafficked to the PM by a non-vesicular pathway. Transfer of ABCG1-mobilized cholesterol from the cytoplasmic face of LEs to the PM and concomitant removal of cholesterol from the outer leaflet of the PM bilayer by extracellular acceptors suggests that ABCG1 mobilizes cholesterol on both sides of the lipid bilayer for removal by acceptors. ABCG1 increased uptake of HDL into LEs, consistent with a potential ABCG1-mediated cholesterol efflux pathway involving HDL resecretion. Thus, ABCG1 at the PM mobilizes PM cholesterol and ABCG1 in LE/LYS generates mobile pools of cholesterol that can traffic by both vesicular and non-vesicular pathways to the PM where it can also be transferred to extracellular acceptors with a lipid surface.
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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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48
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Feng X, Xiong J, Lu Y, Xia X, Zhu MX. Differential mechanisms of action of the mucolipin synthetic agonist, ML-SA1, on insect TRPML and mammalian TRPML1. Cell Calcium 2014; 56:446-56. [PMID: 25266962 DOI: 10.1016/j.ceca.2014.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/08/2014] [Accepted: 09/10/2014] [Indexed: 10/24/2022]
Abstract
Mucolipin synthetic agonist 1 (ML-SA1) was recently identified to activate mammalian TRPML channels and shown to alleviate lipid accumulation in lysosomes of cellular models of lysosome storage diseases, mucolipidosis type IV (MLIV) and Niemann-Pick's disease type C (NPC). Owning to its potential use in complimenting genetic studies in Drosophila melanogaster to elucidate the cellular and physiological functions of TRPML channels, we examined the effect of ML-SA1 on Drosophila TRPML expressed in HEK293 cells using whole-cell, inside-out, and whole-lysosome electrophysiological recordings. We previously showed that when expressed in HEK293 cells, Drosophila TRPML was localized and functional on both plasma membrane and endolysosome. We show here that in both inside-out patches excised from the plasma membrane and whole-lysosome recordings from enlarged endolysosome vacuoles, ML-SA1 failed to activate TRPML unless exogenous phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] was applied. At 1 μM ML-SA1, the sensitivity of TRPML to PI(3,5)P2 increased approximately by 10-fold and at 10 μM ML-SA1, the deactivation of PI(3,5)P2-evoked TRPML currents was markedly slowed. On the other hand, constitutive activation of TRPML by a mutation that mimics the varitint-waddler (Va) mutation of mouse TRPML3 rendered the insect channel sensitive to activation by ML-SA1 alone. Moreover, different from the insect TRPML, mouse TRPML1 was readily activated by ML-SA1 independent of PI(3,5)P2. Thus, our data reveal that while ML-SA1 acts as a true agonist at mouse TRPML1, it behaves as an allosteric activator of the Drosophila TRPML, showing dependence on and the ability to stabilize open conformation of the insect channels.
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Affiliation(s)
- Xinghua Feng
- The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China; Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jian Xiong
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Graduate Program in Cell and Regulatory Biology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yungang Lu
- The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China; Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Xuefeng Xia
- The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China; Center for Genomic Medicine, Houston Methodist Research Institute, Houston, TX 77030, USA.
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA; Graduate Program in Cell and Regulatory Biology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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Grishchuk Y, Sri S, Rudinskiy N, Ma W, Stember KG, Cottle MW, Sapp E, Difiglia M, Muzikansky A, Betensky RA, Wong AMS, Bacskai BJ, Hyman BT, Kelleher RJ, Cooper JD, Slaugenhaupt SA. Behavioral deficits, early gliosis, dysmyelination and synaptic dysfunction in a mouse model of mucolipidosis IV. Acta Neuropathol Commun 2014; 2:133. [PMID: 25200117 PMCID: PMC4173007 DOI: 10.1186/s40478-014-0133-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 08/26/2014] [Indexed: 12/04/2022] Open
Abstract
Mucolipidosis IV (MLIV) is caused by mutations in the gene MCOLN1. Patients with MLIV have severe neurologic deficits and very little is known about the brain pathology in this lysosomal disease. Using an accurate mouse model of mucolipidosis IV, we observed early behavioral deficits which were accompanied by activation of microglia and astrocytes. The glial activation that persisted during the course of disease was not accompanied by neuronal loss even at the late stage. In vivo [Ca2+]-imaging revealed no changes in resting [Ca2+] levels in Mcoln1−/− cortical neurons, implying their physiological health. Despite the absence of neuron loss, we observed alterations in synaptic plasticity, as indicated by elevated paired-pulse facilitation and enhanced long-term potentiation. Myelination deficits and severely dysmorphic corpus callosum were present early and resembled white matter pathology in mucolipidosis IV patients. These results indicate the early involvement of glia, and challenge the traditional view of mucolipidosis IV as an overtly neurodegenerative condition.
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50
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Chen CC, Keller M, Hess M, Schiffmann R, Urban N, Wolfgardt A, Schaefer M, Bracher F, Biel M, Wahl-Schott C, Grimm C. A small molecule restores function to TRPML1 mutant isoforms responsible for mucolipidosis type IV. Nat Commun 2014; 5:4681. [PMID: 25119295 DOI: 10.1038/ncomms5681] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/11/2014] [Indexed: 11/08/2022] Open
Abstract
Mucolipidosis type IV (MLIV) is an autosomal recessive lysosomal storage disorder often characterized by severe neurodevelopmental abnormalities and neuro-retinal degeneration. Mutations in the TRPML1 gene are causative for MLIV. We used lead optimization strategies to identify--and MLIV patient fibroblasts to test--small-molecule activators for their potential to restore TRPML1 mutant channel function. Using the whole-lysosome planar patch-clamp technique, we found that activation of MLIV mutant isoforms by the endogenous ligand PI(3,5)P2 is strongly reduced, while activity can be increased using synthetic ligands. We also found that the F465L mutation renders TRPML1 pH insensitive, while F408Δ impacts synthetic ligand binding. Trafficking defects and accumulation of zinc in lysosomes of MLIV mutant fibroblasts can be rescued by the small molecule treatment. Collectively, our data demonstrate that small molecules can be used to restore channel function and rescue disease associated abnormalities in patient cells expressing specific MLIV point mutations.
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Affiliation(s)
- Cheng-Chang Chen
- 1] Department of Pharmacy-Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Munchen 81377, Germany [2]
| | - Marco Keller
- 1] Department of Pharmacy, Ludwig-Maximilians-Universität München, Munchen 81377, Germany [2]
| | - Martin Hess
- Department of Biology, Ludwig-Maximilians-Universität München, Munchen 82152, Germany
| | - Raphael Schiffmann
- Institute of Metabolic Disease, Baylor Research Institute, Dallas, Texas, USA
| | - Nicole Urban
- Rudolf-Boehm-Institute for Pharmacology and Toxicolgy, Universität Leipzig, Leipzig 04107, Germany
| | - Annette Wolfgardt
- Department of Pharmacy, Ludwig-Maximilians-Universität München, Munchen 81377, Germany
| | - Michael Schaefer
- Rudolf-Boehm-Institute for Pharmacology and Toxicolgy, Universität Leipzig, Leipzig 04107, Germany
| | - Franz Bracher
- Department of Pharmacy, Ludwig-Maximilians-Universität München, Munchen 81377, Germany
| | - Martin Biel
- Department of Pharmacy-Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Munchen 81377, Germany
| | - Christian Wahl-Schott
- Department of Pharmacy-Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Munchen 81377, Germany
| | - Christian Grimm
- 1] Department of Pharmacy-Center for Drug Research and Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Munchen 81377, Germany [2]
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