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Chen Q, Kou H, Demy DL, Liu W, Li J, Wen Z, Herbomel P, Huang Z, Zhang W, Xu J. The different roles of V-ATPase a subunits in phagocytosis/endocytosis and autophagy. Autophagy 2024:1-17. [PMID: 38873931 DOI: 10.1080/15548627.2024.2366748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 06/07/2024] [Indexed: 06/15/2024] Open
Abstract
Microglia are specialized macrophages responsible for the clearance of dead neurons and pathogens by phagocytosis and degradation. The degradation requires phagosome maturation and acidification provided by the vesicular- or vacuolar-type H+-translocating adenosine triphosphatase (V-ATPase), which is composed of the cytoplasmic V1 domain and the membrane-embedded Vo domain. The V-ATPase a subunit, an integral part of the Vo domain, has four isoforms in mammals. The functions of different isoforms on phagosome maturation in different cells/species remain controversial. Here we show that mutations of both the V-ATPase Atp6v0a1 and Tcirg1b/Atp6v0a3 subunits lead to the accumulation of phagosomes in zebrafish microglia. However, their mechanisms are different. The V-ATPase Atp6v0a1 subunit is mainly distributed in early and late phagosomes. Defects of this subunit lead to a defective transition from early phagosomes to late phagosomes. In contrast, The V-ATPase Tcirg1b/Atp6v0a3 subunit is primarily located on lysosomes and regulates late phagosome-lysosomal fusion. Defective Tcirg1b/Atp6v0a3, but not Atp6v0a1 subunit leads to reduced acidification and impaired macroautophagy/autophagy in microglia. We further showed that ATP6V0A1/a1 and TCIRG1/a3 subunits in mouse macrophages preferentially located in endosomes and lysosomes, respectively. Blocking these subunits disrupted early-to-late endosome transition and endosome-to-lysosome fusion, respectively. Taken together, our results highlight the essential and conserved roles played by different V-ATPase subunits in multiple steps of phagocytosis and endocytosis across various species.Abbrevations: Apoe: apolipoprotein E; ANXA5/annexin V: annexin A5; ATP6V0A1/a1: ATPase H+-transporting V0 subunit a1; ATP6V0A2/a2: ATPase H+-transporting V0 subunit a2; ATP6V0A4/a4: ATPase H+-transporting V0 subunit a4; dpf: days post-fertilization; EEA1: early endosome antigen 1; HOPS: homotypic fusion and protein sorting; LAMP1: lysosomal associated membrane protein 1; Lcp1: lymphocyte cytosolic protein 1 (L-plastin); Map1lc3/Lc3: microtubule-associated protein 1 light chain 3; NR: neutral red; PBS: phosphate-buffered saline; PtdIns: phosphatidylinositol; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns(3,5)P2: phosphatidylinositol (3,5)-bisphosphate; RAB4: RAB4, member RAS oncogene family; RAB5: RAB5, member RAS oncogene family; RAB7: RAB7, member RAS oncogene family; TCIRG1/Atp6v0a3/a3: T cell immune regulator 1, ATPase H+-transporting V0 subunit a3; V-ATPase: vacuolar-type H+-translocating adenosine triphosphatase; Xla.Tubb2b/NBT: tubulin beta 2B class IIb.
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Affiliation(s)
- Qi Chen
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, PR China
| | - Hanjing Kou
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, China
| | - Doris Lou Demy
- Institut Pasteur, Department of Developmental & Stem Cell Biology, Paris, France
- CNRS, UMR 3738, Paris, France
| | - Wei Liu
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, China
| | - Jianchao Li
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, 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, Hong Kong, PR China
| | - Philippe Herbomel
- Institut Pasteur, Department of Developmental & Stem Cell Biology, Paris, France
- CNRS, UMR 3738, Paris, France
| | - Zhibin Huang
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, China
| | - Wenqing Zhang
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, China
- Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen, China
| | - Jin Xu
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, China
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2
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Vatte S, Ugale R. HIF-1, an important regulator in potential new therapeutic approaches to ischemic stroke. Neurochem Int 2023; 170:105605. [PMID: 37657765 DOI: 10.1016/j.neuint.2023.105605] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/03/2023]
Abstract
Ischemic stroke is a leading cause of disability and mortality worldwide due to the narrow therapeutic window of the only approved therapies like intravenous thrombolysis and thrombectomy. Hypoxia inducible factor-1α (HIF-1α) is a sensitive regulator of oxygen homeostasis, and its expression is rapidly induced after hypoxia/ischemia. It plays an extensive role in the pathophysiology of stroke by regulating multiple pathways including glucose metabolism, angiogenesis, neuronal survival, neuroinflammation and blood brain barrier regulation. Here, we give a brief overview of the HIF-1α-targeting strategies currently under investigation and summarise recent research on how HIF-1α is regulated in various brain cells, including neurons and microglia, at various stages in ischemic stroke. The roles of HIF-1 in stroke varies with ischemic time and degree of ischemia, are still up for debate. More focus has been placed on prospective HIF-1α targeting drugs, such as HIF-1α activator, HIF-1α stabilizers, and natural compounds. In this review, we have highlighted the regulation of HIF-1α in the novel therapeutic approaches for treatment of stroke.
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Affiliation(s)
- Sneha Vatte
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur, 440033, India.
| | - Rajesh Ugale
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur, 440033, India.
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Lovero D, Porcelli D, Giordano L, Lo Giudice C, Picardi E, Pesole G, Pignataro E, Palazzo A, Marsano RM. Structural and Comparative Analyses of Insects Suggest the Presence of an Ultra-Conserved Regulatory Element of the Genes Encoding Vacuolar-Type ATPase Subunits and Assembly Factors. BIOLOGY 2023; 12:1127. [PMID: 37627011 PMCID: PMC10452791 DOI: 10.3390/biology12081127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/28/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023]
Abstract
Gene and genome comparison represent an invaluable tool to identify evolutionarily conserved sequences with possible functional significance. In this work, we have analyzed orthologous genes encoding subunits and assembly factors of the V-ATPase complex, an important enzymatic complex of the vacuolar and lysosomal compartments of the eukaryotic cell with storage and recycling functions, respectively, as well as the main pump in the plasma membrane that energizes the epithelial transport in insects. This study involves 70 insect species belonging to eight insect orders. We highlighted the conservation of a short sequence in the genes encoding subunits of the V-ATPase complex and their assembly factors analyzed with respect to their exon-intron organization of those genes. This study offers the possibility to study ultra-conserved regulatory elements under an evolutionary perspective, with the aim of expanding our knowledge on the regulation of complex gene networks at the basis of organellar biogenesis and cellular organization.
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Affiliation(s)
- Domenica Lovero
- Dipartimento di Bioscienze Biotecnologie e Ambiente, Università Degli Studi di Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.L.); (D.P.); (E.P.); (G.P.); (E.P.); (A.P.)
- MASMEC Biomed S.p.A., Via Delle Violette 14, 70026 Modugno, Italy
| | - Damiano Porcelli
- Dipartimento di Bioscienze Biotecnologie e Ambiente, Università Degli Studi di Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.L.); (D.P.); (E.P.); (G.P.); (E.P.); (A.P.)
- METALABS S.R.L., Corso A. De Gasperi 381/1, 70125 Bari, Italy
| | - Luca Giordano
- Cardio-Pulmonary Institute (CPI), Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Aulweg 130, 35392 Giessen, Germany;
| | - Claudio Lo Giudice
- Istituto di Tecnologie Biomediche (ITB), Consiglio Nazionale Delle Ricerche, Via Giovanni Amendola, 122, 70126 Bari, Italy;
| | - Ernesto Picardi
- Dipartimento di Bioscienze Biotecnologie e Ambiente, Università Degli Studi di Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.L.); (D.P.); (E.P.); (G.P.); (E.P.); (A.P.)
| | - Graziano Pesole
- Dipartimento di Bioscienze Biotecnologie e Ambiente, Università Degli Studi di Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.L.); (D.P.); (E.P.); (G.P.); (E.P.); (A.P.)
| | - Eugenia Pignataro
- Dipartimento di Bioscienze Biotecnologie e Ambiente, Università Degli Studi di Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.L.); (D.P.); (E.P.); (G.P.); (E.P.); (A.P.)
| | - Antonio Palazzo
- Dipartimento di Bioscienze Biotecnologie e Ambiente, Università Degli Studi di Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.L.); (D.P.); (E.P.); (G.P.); (E.P.); (A.P.)
| | - René Massimiliano Marsano
- Dipartimento di Bioscienze Biotecnologie e Ambiente, Università Degli Studi di Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.L.); (D.P.); (E.P.); (G.P.); (E.P.); (A.P.)
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4
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Indrawinata K, Argiropoulos P, Sugita S. Structural and functional understanding of disease-associated mutations in V-ATPase subunit a1 and other isoforms. Front Mol Neurosci 2023; 16:1135015. [PMID: 37465367 PMCID: PMC10352029 DOI: 10.3389/fnmol.2023.1135015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 06/09/2023] [Indexed: 07/20/2023] Open
Abstract
The vacuolar-type ATPase (V-ATPase) is a multisubunit protein composed of the cytosolic adenosine triphosphate (ATP) hydrolysis catalyzing V1 complex, and the integral membrane complex, Vo, responsible for proton translocation. The largest subunit of the Vo complex, subunit a, enables proton translocation upon ATP hydrolysis, mediated by the cytosolic V1 complex. Four known subunit a isoforms (a1-a4) are expressed in different cellular locations. Subunit a1 (also known as Voa1), the neural isoform, is strongly expressed in neurons and is encoded by the ATP6V0A1 gene. Global knockout of this gene in mice causes embryonic lethality, whereas pyramidal neuron-specific knockout resulted in neuronal cell death with impaired spatial and learning memory. Recently reported, de novo and biallelic mutations of the human ATP6V0A1 impair autophagic and lysosomal activities, contributing to neuronal cell death in developmental and epileptic encephalopathies (DEE) and early onset progressive myoclonus epilepsy (PME). The de novo heterozygous R740Q mutation is the most recurrent variant reported in cases of DEE. Homology studies suggest R740 deprotonates protons from specific glutamic acid residues in subunit c, highlighting its importance to the overall V-ATPase function. In this paper, we discuss the structure and mechanism of the V-ATPase, emphasizing how mutations in subunit a1 can lead to lysosomal and autophagic dysfunction in neurodevelopmental disorders, and how mutations to the non-neural isoforms, a2-a4, can also lead to various genetic diseases. Given the growing discovery of disease-causing variants of V-ATPase subunit a and its function as a pump-based regulator of intracellular organelle pH, this multiprotein complex warrants further investigation.
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Affiliation(s)
- Karen Indrawinata
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Peter Argiropoulos
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Shuzo Sugita
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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5
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Tuli F, Kane PM. The cytosolic N-terminal domain of V-ATPase a-subunits is a regulatory hub targeted by multiple signals. Front Mol Biosci 2023; 10:1168680. [PMID: 37398550 PMCID: PMC10313074 DOI: 10.3389/fmolb.2023.1168680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/05/2023] [Indexed: 07/04/2023] Open
Abstract
Vacuolar H+-ATPases (V-ATPases) acidify several organelles in all eukaryotic cells and export protons across the plasma membrane in a subset of cell types. V-ATPases are multisubunit enzymes consisting of a peripheral subcomplex, V1, that is exposed to the cytosol and an integral membrane subcomplex, Vo, that contains the proton pore. The Vo a-subunit is the largest membrane subunit and consists of two domains. The N-terminal domain of the a-subunit (aNT) interacts with several V1 and Vo subunits and serves to bridge the V1 and Vo subcomplexes, while the C-terminal domain contains eight transmembrane helices, two of which are directly involved in proton transport. Although there can be multiple isoforms of several V-ATPase subunits, the a-subunit is encoded by the largest number of isoforms in most organisms. For example, the human genome encodes four a-subunit isoforms that exhibit a tissue- and organelle-specific distribution. In the yeast S. cerevisiae, the two a-subunit isoforms, Golgi-enriched Stv1 and vacuolar Vph1, are the only V-ATPase subunit isoforms. Current structural information indicates that a-subunit isoforms adopt a similar backbone structure but sequence variations allow for specific interactions during trafficking and in response to cellular signals. V-ATPases are subject to several types of environmental regulation that serve to tune their activity to their cellular location and environmental demands. The position of the aNT domain in the complex makes it an ideal target for modulating V1-Vo interactions and regulating enzyme activity. The yeast a-subunit isoforms have served as a paradigm for dissecting interactions of regulatory inputs with subunit isoforms. Importantly, structures of yeast V-ATPases containing each a-subunit isoform are available. Chimeric a-subunits combining elements of Stv1NT and Vph1NT have provided insights into how regulatory inputs can be integrated to allow V-ATPases to support cell growth under different stress conditions. Although the function and distribution of the four mammalian a-subunit isoforms present additional complexity, it is clear that the aNT domains of these isoforms are also subject to multiple regulatory interactions. Regulatory mechanisms that target mammalian a-subunit isoforms, and specifically the aNT domains, will be described. Altered V-ATPase function is associated with multiple diseases in humans. The possibility of regulating V-ATPase subpopulations via their isoform-specific regulatory interactions are discussed.
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Affiliation(s)
| | - Patricia M. Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
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6
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Lo CH, Zeng J. Defective lysosomal acidification: a new prognostic marker and therapeutic target for neurodegenerative diseases. Transl Neurodegener 2023; 12:29. [PMID: 37287072 DOI: 10.1186/s40035-023-00362-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 05/12/2023] [Indexed: 06/09/2023] Open
Abstract
Lysosomal acidification dysfunction has been implicated as a key driving factor in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Multiple genetic factors have been linked to lysosomal de-acidification through impairing the vacuolar-type ATPase and ion channels on the organelle membrane. Similar lysosomal abnormalities are also present in sporadic forms of neurodegeneration, although the underlying pathogenic mechanisms are unclear and remain to be investigated. Importantly, recent studies have revealed early occurrence of lysosomal acidification impairment before the onset of neurodegeneration and late-stage pathology. However, there is a lack of methods for organelle pH monitoring in vivo and a dearth of lysosome-acidifying therapeutic agents. Here, we summarize and present evidence for the notion of defective lysosomal acidification as an early indicator of neurodegeneration and urge the critical need for technological advancement in developing tools for lysosomal pH monitoring and detection both in vivo and for clinical applications. We further discuss current preclinical pharmacological agents that modulate lysosomal acidification, including small molecules and nanomedicine, and their potential clinical translation into lysosome-targeting therapies. Both timely detection of lysosomal dysfunction and development of therapeutics that restore lysosomal function represent paradigm shifts in targeting neurodegenerative diseases.
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Affiliation(s)
- Chih Hung Lo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore.
| | - Jialiu Zeng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore.
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7
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Yusuff T, Chang YC, Sang TK, Jackson GR, Chatterjee S. Codon-optimized TDP-43 mediates neurodegeneration in a Drosophila model of ALS/FTLD. Front Genet 2023; 14:881638. [PMID: 36968586 PMCID: PMC10034021 DOI: 10.3389/fgene.2023.881638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 02/13/2023] [Indexed: 03/11/2023] Open
Abstract
Transactive response DNA binding protein-43 (TDP-43) is known to mediate neurodegeneration associated with amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). The exact mechanism by which TDP-43 exerts toxicity in the brains, spinal cord, and lower motor neurons of affected patients remains unclear. In a novel Drosophila melanogaster model, we report gain-of-function phenotypes due to misexpression of insect codon-optimized version of human wild-type TDP-43 (CO-TDP-43) using both the binary GAL4/UAS system and direct promoter fusion constructs. The CO-TDP-43 model showed robust tissue specific phenotypes in the adult eye, wing, and bristles in the notum. Compared to non-codon optimized transgenic flies, the CO-TDP-43 flies produced increased amount of high molecular weight protein, exhibited pathogenic phenotypes, and showed cytoplasmic aggregation with both nuclear and cytoplasmic expression of TDP-43. Further characterization of the adult retina showed a disruption in the morphology and function of the photoreceptor neurons with the presence of acidic vacuoles that are characteristic of autophagy. Based on our observations, we propose that TDP-43 has the propensity to form toxic protein aggregates via a gain-of-function mechanism, and such toxic overload leads to activation of protein degradation pathways such as autophagy. The novel codon optimized TDP-43 model is an excellent resource that could be used in genetic screens to identify and better understand the exact disease mechanism of TDP-43 proteinopathies and find potential therapeutic targets.
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Affiliation(s)
- Tanzeen Yusuff
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch at Galveston, Galveston, TX, United States
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch at Galveston, Galveston, TX, United States
- *Correspondence: Tanzeen Yusuff, ; Shreyasi Chatterjee,
| | - Ya-Chu Chang
- Department of Life Science, Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan
| | - Tzu-Kang Sang
- Department of Life Science, Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan
| | - George R. Jackson
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch at Galveston, Galveston, TX, United States
- Department of Neurology, University of Texas Medical Branch at Galveston, Galveston, TX, United States
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX, United States
- Department of Neurology, Baylor College of Medicine, Houston, TX, United States
- National Parkinson’s Disease Research Education and Clinical Center, Michael E. DeBakey VA Medical Center, Houston, TX, United States
| | - Shreyasi Chatterjee
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch at Galveston, Galveston, TX, United States
- Department of Neurology, University of Texas Medical Branch at Galveston, Galveston, TX, United States
- Department of Biochemistry, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
- *Correspondence: Tanzeen Yusuff, ; Shreyasi Chatterjee,
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8
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Lévêque C, Maulet Y, Wang Q, Rame M, Rodriguez L, Mochida S, Sangiardi M, Youssouf F, Iborra C, Seagar M, Vitale N, El Far O. A Role for the V0 Sector of the V-ATPase in Neuroexocytosis: Exogenous V0d Blocks Complexin and SNARE Interactions with V0c. Cells 2023; 12:cells12050750. [PMID: 36899886 PMCID: PMC10001230 DOI: 10.3390/cells12050750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
V-ATPase is an important factor in synaptic vesicle acidification and is implicated in synaptic transmission. Rotation in the extra-membranous V1 sector drives proton transfer through the membrane-embedded multi-subunit V0 sector of the V-ATPase. Intra-vesicular protons are then used to drive neurotransmitter uptake by synaptic vesicles. V0a and V0c, two membrane subunits of the V0 sector, have been shown to interact with SNARE proteins, and their photo-inactivation rapidly impairs synaptic transmission. V0d, a soluble subunit of the V0 sector strongly interacts with its membrane-embedded subunits and is crucial for the canonic proton transfer activity of the V-ATPase. Our investigations show that the loop 1.2 of V0c interacts with complexin, a major partner of the SNARE machinery and that V0d1 binding to V0c inhibits this interaction, as well as V0c association with SNARE complex. The injection of recombinant V0d1 in rat superior cervical ganglion neurons rapidly reduced neurotransmission. In chromaffin cells, V0d1 overexpression and V0c silencing modified in a comparable manner several parameters of unitary exocytotic events. Our data suggest that V0c subunit promotes exocytosis via interactions with complexin and SNAREs and that this activity can be antagonized by exogenous V0d.
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Affiliation(s)
- Christian Lévêque
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Yves Maulet
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Qili Wang
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67000 Strasbourg, France
| | - Marion Rame
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67000 Strasbourg, France
| | - Léa Rodriguez
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Sumiko Mochida
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan
| | - Marion Sangiardi
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Fahamoe Youssouf
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Cécile Iborra
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Michael Seagar
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Université de Strasbourg, 67000 Strasbourg, France
- Correspondence: (N.V.); or (O.E.F.); Tel.: +33-(0)3-8845-6712 (N.V.); +33-(0)4-9169-8860 (O.E.F.)
| | - Oussama El Far
- INSERM UMR_S 1072, 13015 Marseille, France
- Aix-Marseille Université, 13015 Marseille, France
- Correspondence: (N.V.); or (O.E.F.); Tel.: +33-(0)3-8845-6712 (N.V.); +33-(0)4-9169-8860 (O.E.F.)
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9
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Wang Q, Wolf A, Ozkan S, Richert L, Mely Y, Chasserot-Golaz S, Ory S, Gasman S, Vitale N. V-ATPase modulates exocytosis in neuroendocrine cells through the activation of the ARNO-Arf6-PLD pathway and the synthesis of phosphatidic acid. Front Mol Biosci 2023; 10:1163545. [PMID: 37091866 PMCID: PMC10119424 DOI: 10.3389/fmolb.2023.1163545] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/23/2023] [Indexed: 04/25/2023] Open
Abstract
Although there is mounting evidence indicating that lipids serve crucial functions in cells and are implicated in a growing number of human diseases, their precise roles remain largely unknown. This is particularly true in the case of neurosecretion, where fusion with the plasma membrane of specific membrane organelles is essential. Yet, little attention has been given to the role of lipids. Recent groundbreaking research has emphasized the critical role of lipid localization at exocytotic sites and validated the essentiality of fusogenic lipids, such as phospholipase D (PLD)-generated phosphatidic acid (PA), during membrane fusion. Nevertheless, the regulatory mechanisms synchronizing the synthesis of these key lipids and neurosecretion remain poorly understood. The vacuolar ATPase (V-ATPase) has been involved both in vesicle neurotransmitter loading and in vesicle fusion. Thus, it represents an ideal candidate to regulate the fusogenic status of secretory vesicles according to their replenishment state. Indeed, the cytosolic V1 and vesicular membrane-associated V0 subdomains of V-ATPase were shown to dissociate during the stimulation of neurosecretory cells. This allows the subunits of the vesicular V0 to interact with different proteins of the secretory machinery. Here, we show that V0a1 interacts with the Arf nucleotide-binding site opener (ARNO) and promotes the activation of the Arf6 GTPase during the exocytosis in neuroendocrine cells. When the interaction between V0a1 and ARNO was disrupted, it resulted in the inhibition of PLD activation, synthesis of phosphatidic acid during exocytosis, and changes in the timing of fusion events. These findings indicate that the separation of V1 from V0 could function as a signal to initiate the ARNO-Arf6-PLD1 pathway and facilitate the production of phosphatidic acid, which is essential for effective exocytosis in neuroendocrine cells.
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Affiliation(s)
- Qili Wang
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Alexander Wolf
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Sebahat Ozkan
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Ludovic Richert
- Laboratoire de Bioimagerie et Pathologies, Faculté de Pharmacie, CNRS UMR and Université de Strasbourg, Strasbourg, France
| | - Yves Mely
- Laboratoire de Bioimagerie et Pathologies, Faculté de Pharmacie, CNRS UMR and Université de Strasbourg, Strasbourg, France
| | - Sylvette Chasserot-Golaz
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Stéphane Ory
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Stéphane Gasman
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
- *Correspondence: Nicolas Vitale,
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10
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Ríos-Barrera LD, Leptin M. An endosome-associated actin network involved in directed apical plasma membrane growth. J Biophys Biochem Cytol 2022; 221:212975. [PMID: 35061016 PMCID: PMC8789128 DOI: 10.1083/jcb.202106124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/06/2021] [Accepted: 01/04/2022] [Indexed: 12/22/2022] Open
Abstract
Membrane trafficking plays many roles in morphogenesis, from bulk membrane provision to targeted delivery of proteins and other cargos. In tracheal terminal cells of the Drosophila respiratory system, transport through late endosomes balances membrane delivery between the basal plasma membrane and the apical membrane, which forms a subcellular tube, but it has been unclear how the direction of growth of the subcellular tube with the overall cell growth is coordinated. We show here that endosomes also organize F-actin. Actin assembles around late endocytic vesicles in the growth cone of the cell, reaching from the tip of the subcellular tube to the leading filopodia of the basal membrane. Preventing nucleation of endosomal actin disturbs the directionality of tube growth, uncoupling it from the direction of cell elongation. Severing actin in this area affects tube integrity. Our findings show a new role for late endosomes in directing morphogenesis by organizing actin, in addition to their known role in membrane and protein trafficking.
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Affiliation(s)
- Luis Daniel Ríos-Barrera
- Directors’ Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Maria Leptin
- Directors’ Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Institute for Genetics, University of Cologne, Cologne, Germany
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11
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Cai Q, Ganesan D. Regulation of neuronal autophagy and the implications in neurodegenerative diseases. Neurobiol Dis 2022; 162:105582. [PMID: 34890791 PMCID: PMC8764935 DOI: 10.1016/j.nbd.2021.105582] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/22/2021] [Accepted: 12/06/2021] [Indexed: 01/03/2023] Open
Abstract
Neurons are highly polarized and post-mitotic cells with the specific requirements of neurotransmission accompanied by high metabolic demands that create a unique challenge for the maintenance of cellular homeostasis. Thus, neurons rely heavily on autophagy that constitutes a key quality control system by which dysfunctional cytoplasmic components, protein aggregates, and damaged organelles are sequestered within autophagosomes and then delivered to the lysosome for degradation. While mature lysosomes are predominantly located in the soma of neurons, the robust, constitutive biogenesis of autophagosomes occurs in the synaptic terminal via a conserved pathway that is required to maintain synaptic integrity and function. Following formation, autophagosomes fuse with late endosomes and then are rapidly and efficiently transported by the microtubule-based cytoplasmic dynein motor along the axon toward the soma for lysosomal clearance. In this review, we highlight the recent knowledge of the roles of autophagy in neuronal health and disease. We summarize the available evidence about the normal functions of autophagy as a protective factor against neurodegeneration and discuss the mechanism underlying neuronal autophagy regulation. Finally, we describe how autophagy function is affected in major neurodegenerative diseases with a special focus on Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis.
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12
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He Q, Ma Y, Liu J, Zhang D, Ren J, Zhao R, Chang J, Guo ZN, Yang Y. Biological Functions and Regulatory Mechanisms of Hypoxia-Inducible Factor-1α in Ischemic Stroke. Front Immunol 2021; 12:801985. [PMID: 34966392 PMCID: PMC8710457 DOI: 10.3389/fimmu.2021.801985] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 11/26/2021] [Indexed: 12/15/2022] Open
Abstract
Ischemic stroke is caused by insufficient cerebrovascular blood and oxygen supply. It is a major contributor to death or disability worldwide and has become a heavy societal and clinical burden. To date, effective treatments for ischemic stroke are limited, and innovative therapeutic methods are urgently needed. Hypoxia inducible factor-1α (HIF-1α) is a sensitive regulator of oxygen homeostasis, and its expression is rapidly induced after hypoxia/ischemia. It plays an extensive role in the pathophysiology of stroke, including neuronal survival, neuroinflammation, angiogenesis, glucose metabolism, and blood brain barrier regulation. In addition, the spatiotemporal expression profile of HIF-1α in the brain shifts with the progression of ischemic stroke; this has led to contradictory findings regarding its function in previous studies. Therefore, unveiling the Janus face of HIF-1α and its target genes in different type of cells and exploring the role of HIF-1α in inflammatory responses after ischemia is of great importance for revealing the pathogenesis and identifying new therapeutic targets for ischemic stroke. Herein, we provide a succinct overview of the current approaches targeting HIF-1α and summarize novel findings concerning HIF-1α regulation in different types of cells within neurovascular units, including neurons, endothelial cells, astrocytes, and microglia, during the different stages of ischemic stroke. The current representative translational approaches focused on neuroprotection by targeting HIF-1α are also discussed.
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Affiliation(s)
- Qianyan He
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Yinzhong Ma
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jie Liu
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Dianhui Zhang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Jiaxin Ren
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Ruoyu Zhao
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - JunLei Chang
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zhen-Ni Guo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Yi Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
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13
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Grosso Jasutkar H, Yamamoto A. Do Changes in Synaptic Autophagy Underlie the Cognitive Impairments in Huntington's Disease? J Huntingtons Dis 2021; 10:227-238. [PMID: 33780373 PMCID: PMC8293641 DOI: 10.3233/jhd-200466] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Although Huntington's disease (HD) is classically considered from the perspective of the motor syndrome, the cognitive changes in HD are prominent and often an early manifestation of disease. As such, investigating the underlying pathophysiology of cognitive changes may give insight into important and early neurodegenerative events. In this review, we first discuss evidence from both HD patients and animal models that cognitive changes correlate with early pathological changes at the synapse, an observation that is similarly made in other neurodegenerative conditions that primarily affect cognition. We then describe how autophagy plays a critical role supporting synaptic maintenance in the healthy brain, and how autophagy dysfunction in HD may thereby lead to impaired synaptic maintenance and thus early manifestations of disease.
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Affiliation(s)
| | - Ai Yamamoto
- Department of Neurology, Columbia University, New York, NY, USA.,Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
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14
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Aoto K, Kato M, Akita T, Nakashima M, Mutoh H, Akasaka N, Tohyama J, Nomura Y, Hoshino K, Ago Y, Tanaka R, Epstein O, Ben-Haim R, Heyman E, Miyazaki T, Belal H, Takabayashi S, Ohba C, Takata A, Mizuguchi T, Miyatake S, Miyake N, Fukuda A, Matsumoto N, Saitsu H. ATP6V0A1 encoding the a1-subunit of the V0 domain of vacuolar H +-ATPases is essential for brain development in humans and mice. Nat Commun 2021; 12:2107. [PMID: 33833240 PMCID: PMC8032687 DOI: 10.1038/s41467-021-22389-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 03/05/2021] [Indexed: 02/01/2023] Open
Abstract
Vacuolar H+-ATPases (V-ATPases) transport protons across cellular membranes to acidify various organelles. ATP6V0A1 encodes the a1-subunit of the V0 domain of V-ATPases, which is strongly expressed in neurons. However, its role in brain development is unknown. Here we report four individuals with developmental and epileptic encephalopathy with ATP6V0A1 variants: two individuals with a de novo missense variant (R741Q) and the other two individuals with biallelic variants comprising one almost complete loss-of-function variant and one missense variant (A512P and N534D). Lysosomal acidification is significantly impaired in cell lines expressing three missense ATP6V0A1 mutants. Homozygous mutant mice harboring human R741Q (Atp6v0a1R741Q) and A512P (Atp6v0a1A512P) variants show embryonic lethality and early postnatal mortality, respectively, suggesting that R741Q affects V-ATPase function more severely. Lysosomal dysfunction resulting in cell death, accumulated autophagosomes and lysosomes, reduced mTORC1 signaling and synaptic connectivity, and lowered neurotransmitter contents of synaptic vesicles are observed in the brains of Atp6v0a1A512P/A512P mice. These findings demonstrate the essential roles of ATP6V0A1/Atp6v0a1 in neuronal development in terms of integrity and connectivity of neurons in both humans and mice. A member of the vacuolar H+-ATPase family, ATP6V0A1 is involved in lysosomal activity. Here, the authors report that ATP6V0A1 variants identified in individuals with developmental and epileptic encephalopathy are associated with impairment of lysosomal acidification, autophagy and mTORC1 signaling, suggesting an essential role of ATP6V0A1 in brain development.
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Affiliation(s)
- Kazushi Aoto
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan.
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hiroki Mutoh
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Noriyuki Akasaka
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan.,Department of Pediatrics, Niigata Prefecture Hamagumi Medical Rehabilitation Center for Disabled Children, Niigata, Japan
| | - Jun Tohyama
- Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital, Niigata, Japan
| | - Yoshiko Nomura
- Segawa Neurological Clinic for Children, Tokyo, Japan.,Yoshiko Nomura Neurological Clinic for Children, Tokyo, Japan
| | - Kyoko Hoshino
- Segawa Neurological Clinic for Children, Tokyo, Japan.,Segawa Memorial Neurological Clinic for Children, Tokyo, Japan
| | - Yasuhiko Ago
- Department of Neonatology, Ibaraki Children's Hospital, Mito, Japan.,Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Ryuta Tanaka
- Ibaraki Pediatric Education and Training Station, University of Tsukuba, Mito, Japan
| | - Orna Epstein
- Pediatric Neurology and Development Center, Shamir Medical Center, Tzrifin, Beer Yaakov, Israel
| | - Revital Ben-Haim
- Pediatric Neurology and Development Center, Shamir Medical Center, Tzrifin, Beer Yaakov, Israel
| | - Eli Heyman
- Pediatric Neurology and Development Center, Shamir Medical Center, Tzrifin, Beer Yaakov, Israel
| | - Takehiro Miyazaki
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hazrat Belal
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Shuji Takabayashi
- Laboratory Animal Facilities & Services, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Chihiro Ohba
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Atsushi Takata
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan.
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15
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Kohrs FE, Daumann IM, Pavlovic B, Jin EJ, Kiral FR, Lin SC, Port F, Wolfenberg H, Mathejczyk TF, Linneweber GA, Chan CC, Boutros M, Hiesinger PR. Systematic functional analysis of rab GTPases reveals limits of neuronal robustness to environmental challenges in flies. eLife 2021; 10:59594. [PMID: 33666175 PMCID: PMC8016483 DOI: 10.7554/elife.59594] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 03/04/2021] [Indexed: 12/26/2022] Open
Abstract
Rab GTPases are molecular switches that regulate membrane trafficking in all cells. Neurons have particular demands on membrane trafficking and express numerous Rab GTPases of unknown function. Here, we report the generation and characterization of molecularly defined null mutants for all 26 rab genes in Drosophila. In flies, all rab genes are expressed in the nervous system where at least half exhibit particularly high levels compared to other tissues. Surprisingly, loss of any of these 13 nervous system-enriched Rabs yielded viable and fertile flies without obvious morphological defects. However, all 13 mutants differentially affected development when challenged with different temperatures, or neuronal function when challenged with continuous stimulation. We identified a synaptic maintenance defect following continuous stimulation for six mutants, including an autophagy-independent role of rab26. The complete mutant collection generated in this study provides a basis for further comprehensive studies of Rab GTPases during development and function in vivo.
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Affiliation(s)
- Friederike E Kohrs
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Ilsa-Maria Daumann
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Bojana Pavlovic
- German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg, Germany
| | - Eugene Jennifer Jin
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - F Ridvan Kiral
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | | | - Filip Port
- German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg, Germany
| | - Heike Wolfenberg
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Thomas F Mathejczyk
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | - Gerit A Linneweber
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
| | | | - Michael Boutros
- German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg, Germany
| | - P Robin Hiesinger
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
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16
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Santos-Pereira C, Rodrigues LR, Côrte-Real M. Emerging insights on the role of V-ATPase in human diseases: Therapeutic challenges and opportunities. Med Res Rev 2021; 41:1927-1964. [PMID: 33483985 DOI: 10.1002/med.21782] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 12/05/2020] [Accepted: 01/05/2021] [Indexed: 12/13/2022]
Abstract
The control of the intracellular pH is vital for the survival of all organisms. Membrane transporters, both at the plasma and intracellular membranes, are key players in maintaining a finely tuned pH balance between intra- and extracellular spaces, and therefore in cellular homeostasis. V-ATPase is a housekeeping ATP-driven proton pump highly conserved among prokaryotes and eukaryotes. This proton pump, which exhibits a complex multisubunit structure based on cell type-specific isoforms, is essential for pH regulation and for a multitude of ubiquitous and specialized functions. Thus, it is not surprising that V-ATPase aberrant overexpression, mislocalization, and mutations in V-ATPase subunit-encoding genes have been associated with several human diseases. However, the ubiquitous expression of this transporter and the high toxicity driven by its off-target inhibition, renders V-ATPase-directed therapies very challenging and increases the need for selective strategies. Here we review emerging evidence linking V-ATPase and both inherited and acquired human diseases, explore the therapeutic challenges and opportunities envisaged from recent data, and advance future research avenues. We highlight the importance of V-ATPases with unique subunit isoform molecular signatures and disease-associated isoforms to design selective V-ATPase-directed therapies. We also discuss the rational design of drug development pipelines and cutting-edge methodological approaches toward V-ATPase-centered drug discovery. Diseases like cancer, osteoporosis, and even fungal infections can benefit from V-ATPase-directed therapies.
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Affiliation(s)
- Cátia Santos-Pereira
- Department of Biology, Centre of Molecular and Environmental Biology (CBMA), University of Minho, Braga, Portugal.,Department of Biological Engineering, Centre of Biological Engineering (CEB), University of Minho, Braga, Portugal
| | - Lígia R Rodrigues
- Department of Biological Engineering, Centre of Biological Engineering (CEB), University of Minho, Braga, Portugal
| | - Manuela Côrte-Real
- Department of Biology, Centre of Molecular and Environmental Biology (CBMA), University of Minho, Braga, Portugal
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17
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Andres-Alonso M, Kreutz MR, Karpova A. Autophagy and the endolysosomal system in presynaptic function. Cell Mol Life Sci 2020; 78:2621-2639. [PMID: 33340068 PMCID: PMC8004491 DOI: 10.1007/s00018-020-03722-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/17/2020] [Accepted: 11/24/2020] [Indexed: 12/11/2022]
Abstract
The complex morphology of neurons, the specific requirements of synaptic neurotransmission and the accompanying metabolic demands create a unique challenge for proteostasis. The main machineries for neuronal protein synthesis and degradation are localized in the soma, while synaptic junctions are found at vast distances from the cell body. Sophisticated mechanisms must, therefore, ensure efficient delivery of newly synthesized proteins and removal of faulty proteins. These requirements are exacerbated at presynaptic sites, where the demands for protein turnover are especially high due to synaptic vesicle release and recycling that induces protein damage in an intricate molecular machinery, and where replacement of material is hampered by the extreme length of the axon. In this review, we will discuss the contribution of the two major pathways in place, autophagy and the endolysosomal system, to presynaptic protein turnover and presynaptic function. Although clearly different in their biogenesis, both pathways are characterized by cargo collection and transport into distinct membrane-bound organelles that eventually fuse with lysosomes for cargo degradation. We summarize the available evidence with regard to their degradative function, their regulation by presynaptic machinery and the cargo for each pathway. Finally, we will discuss the interplay of both pathways in neurons and very recent findings that suggest non-canonical functions of degradative organelles in synaptic signalling and plasticity.
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Affiliation(s)
- Maria Andres-Alonso
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
- Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany.
- Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany.
- Center for Behavioral Brain Sciences, Otto Von Guericke University, Magdeburg, Germany.
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.
| | - Anna Karpova
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany.
- Center for Behavioral Brain Sciences, Otto Von Guericke University, Magdeburg, Germany.
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18
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Eaton AF, Merkulova M, Brown D. The H +-ATPase (V-ATPase): from proton pump to signaling complex in health and disease. Am J Physiol Cell Physiol 2020; 320:C392-C414. [PMID: 33326313 PMCID: PMC8294626 DOI: 10.1152/ajpcell.00442.2020] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A primary function of the H+-ATPase (or V-ATPase) is to create an electrochemical proton gradient across eukaryotic cell membranes, which energizes fundamental cellular processes. Its activity allows for the acidification of intracellular vesicles and organelles, which is necessary for many essential cell biological events to occur. In addition, many specialized cell types in various organ systems such as the kidney, bone, male reproductive tract, inner ear, olfactory mucosa, and more, use plasma membrane V-ATPases to perform specific activities that depend on extracellular acidification. It is, however, increasingly apparent that V-ATPases are central players in many normal and pathophysiological processes that directly influence human health in many different and sometimes unexpected ways. These include cancer, neurodegenerative diseases, diabetes, and sensory perception, as well as energy and nutrient-sensing functions within cells. This review first covers the well-established role of the V-ATPase as a transmembrane proton pump in the plasma membrane and intracellular vesicles and outlines factors contributing to its physiological regulation in different cell types. This is followed by a discussion of the more recently emerging unconventional roles for the V-ATPase, such as its role as a protein interaction hub involved in cell signaling, and the (patho)physiological implications of these interactions. Finally, the central importance of endosomal acidification and V-ATPase activity on viral infection will be discussed in the context of the current COVID-19 pandemic.
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Affiliation(s)
- Amity F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Maria Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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19
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Mo D, Chen Y, Jiang N, Shen J, Zhang J. Investigation of Isoform Specific Functions of the V-ATPase a Subunit During Drosophila Wing Development. Front Genet 2020; 11:723. [PMID: 32754202 PMCID: PMC7365883 DOI: 10.3389/fgene.2020.00723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022] Open
Abstract
The vacuolar ATPases (V-ATPases) are ATP-dependent proton pumps that play vital roles in eukaryotic cells. Insect V-ATPases are required in nearly all epithelial tissues to regulate a multiplicity of processes including receptor-mediated endocytosis, protein degradation, fluid secretion, and neurotransmission. Composed of fourteen different subunits, several V-ATPase subunits exist in distinct isoforms to perform cell type specific functions. The 100 kD a subunit (Vha100) of V-ATPases are encoded by a family of five genes in Drosophila, but their assignments are not fully understood. Here we report an experimental survey of the Vha100 gene family during Drosophila wing development. A combination of CRISPR-Cas9 mutagenesis, somatic clonal analysis and in vivo RNAi assays is used to characterize the requirement of Vha100 isoforms, and mutants of Vha100-2, Vha100-3, Vha100-4, and Vha100-5 genes were generated. We show that Vha100-3 and Vha100-5 are dispensable for fly development, while Vha100-1 is not critically required in the wing. As for the other two isoforms, we find that Vha100-2 regulates wing cuticle maturation, while Vha100-4 is the single isoform involved in developmental patterning. More specifically, Vha100-4 is required for proper activation of the Wingless signaling pathway during fly wing development. Interestingly, we also find a specific genetic interaction between Vha100-1 and Vha100-4 during wing development. Our results revealed the distinct roles of Vha100 isoforms during insect wing development, providing a rationale for understanding the diverse roles of V-ATPases.
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Affiliation(s)
- Dongqing Mo
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Yao Chen
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Na Jiang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jie Shen
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Junzheng Zhang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
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20
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Lee JH, Wolfe DM, Darji S, McBrayer MK, Colacurcio DJ, Kumar A, Stavrides P, Mohan PS, Nixon RA. β2-adrenergic Agonists Rescue Lysosome Acidification and Function in PSEN1 Deficiency by Reversing Defective ER-to-lysosome Delivery of ClC-7. J Mol Biol 2020; 432:2633-2650. [PMID: 32105735 DOI: 10.1016/j.jmb.2020.02.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 02/06/2023]
Abstract
Lysosomal dysfunction is considered pathogenic in Alzheimer disease (AD). Loss of presenilin-1 (PSEN1) function causing AD impedes acidification via defective vacuolar ATPase (vATPase) V0a1 subunit delivery to lysosomes. We report that isoproterenol (ISO) and related β2-adrenergic agonists reacidify lysosomes in PSEN1 Knock out (KO) cells and fibroblasts from PSEN1 familial AD patients, which restores lysosomal proteolysis, calcium homeostasis, and normal autophagy flux. We identify a novel rescue mechanism involving Portein Kinase A (PKA)-mediated facilitation of chloride channel-7 (ClC-7) delivery to lysosomes which reverses markedly lowered chloride (Cl-) content in PSEN1 KO lysosomes. Notably, PSEN1 loss of function impedes Endoplasmic Reticulum (ER)-to-lysosome delivery of ClC-7. Transcriptomics of PSEN1-deficient cells reveals strongly downregulated ER-to-lysosome transport pathways and reversibility by ISO, thus accounting for lysosomal Cl- deficits that compound pH elevation due to deficient vATPase and its rescue by β2-adrenergic agonists. Our findings uncover a broadened PSEN1 role in lysosomal ion homeostasis and novel pH modulation of lysosomes through β2-adrenergic regulation of ClC-7, which can potentially be modulated therapeutically.
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Affiliation(s)
- Ju-Hyun Lee
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA; Department of Psychiatry, Langone Medical Center, New York, NY, 10016, USA.
| | - Devin M Wolfe
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA
| | - Sandipkumar Darji
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA
| | - Mary Kate McBrayer
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA
| | - Daniel J Colacurcio
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA
| | - Asok Kumar
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA
| | - Philip Stavrides
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA
| | - Panaiyur S Mohan
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA; Department of Psychiatry, Langone Medical Center, New York, NY, 10016, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA; Department of Psychiatry, Langone Medical Center, New York, NY, 10016, USA; Department of Cell Biology, Langone Medical Center, New York, NY, 10016, USA; Neuroscience Institute, New York University, New York, NY 10016, USA.
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21
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Özel MN, Kulkarni A, Hasan A, Brummer J, Moldenhauer M, Daumann IM, Wolfenberg H, Dercksen VJ, Kiral FR, Weiser M, Prohaska S, von Kleist M, Hiesinger PR. Serial Synapse Formation through Filopodial Competition for Synaptic Seeding Factors. Dev Cell 2019; 50:447-461.e8. [PMID: 31353313 DOI: 10.1016/j.devcel.2019.06.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/15/2019] [Accepted: 06/21/2019] [Indexed: 11/15/2022]
Abstract
Following axon pathfinding, growth cones transition from stochastic filopodial exploration to the formation of a limited number of synapses. How the interplay of filopodia and synapse assembly ensures robust connectivity in the brain has remained a challenging problem. Here, we developed a new 4D analysis method for filopodial dynamics and a data-driven computational model of synapse formation for R7 photoreceptor axons in developing Drosophila brains. Our live data support a "serial synapse formation" model, where at any time point only 1-2 "synaptogenic" filopodia suppress the synaptic competence of other filopodia through competition for synaptic seeding factors. Loss of the synaptic seeding factors Syd-1 and Liprin-α leads to a loss of this suppression, filopodial destabilization, and reduced synapse formation. The failure to form synapses can cause the destabilization and secondary retraction of axon terminals. Our model provides a filopodial "winner-takes-all" mechanism that ensures the formation of an appropriate number of synapses.
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Affiliation(s)
- M Neset Özel
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany; Neuroscience Graduate Program, UT Southwestern Medical Center Dallas, Dallas, TX 75390, USA
| | - Abhishek Kulkarni
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Amr Hasan
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Josephine Brummer
- Department of Visual Data Analysis, Zuse Institute Berlin, 14195 Berlin, Germany
| | - Marian Moldenhauer
- Computational Medicine and Numerical Mathematics, Zuse Institute Berlin, 14195 Berlin, Germany; Department of Mathematics and Informatics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Ilsa-Maria Daumann
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Heike Wolfenberg
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Vincent J Dercksen
- Department of Visual Data Analysis, Zuse Institute Berlin, 14195 Berlin, Germany
| | - F Ridvan Kiral
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Martin Weiser
- Computational Medicine and Numerical Mathematics, Zuse Institute Berlin, 14195 Berlin, Germany
| | - Steffen Prohaska
- Department of Visual Data Analysis, Zuse Institute Berlin, 14195 Berlin, Germany
| | - Max von Kleist
- Department of Mathematics and Informatics, Freie Universität Berlin, 14195 Berlin, Germany.
| | - P Robin Hiesinger
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany.
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22
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Hirose T, Cabrera-Socorro A, Chitayat D, Lemonnier T, Féraud O, Cifuentes-Diaz C, Gervasi N, Mombereau C, Ghosh T, Stoica L, Bacha JDA, Yamada H, Lauterbach MA, Guillon M, Kaneko K, Norris JW, Siriwardena K, Blasér S, Teillon J, Mendoza-Londono R, Russeau M, Hadoux J, Ito S, Corvol P, Matheus MG, Holden KR, Takei K, Emiliani V, Bennaceur-Griscelli A, Schwartz CE, Nguyen G, Groszer M. ATP6AP2 variant impairs CNS development and neuronal survival to cause fulminant neurodegeneration. J Clin Invest 2019; 129:2145-2162. [PMID: 30985297 DOI: 10.1172/jci79990] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 03/05/2019] [Indexed: 12/31/2022] Open
Abstract
Vacuolar H+-ATPase-dependent (V-ATPase-dependent) functions are critical for neural proteostasis and are involved in neurodegeneration and brain tumorigenesis. We identified a patient with fulminant neurodegeneration of the developing brain carrying a de novo splice site variant in ATP6AP2 encoding an accessory protein of the V-ATPase. Functional studies of induced pluripotent stem cell-derived (iPSC-derived) neurons from this patient revealed reduced spontaneous activity and severe deficiency in lysosomal acidification and protein degradation leading to neuronal cell death. These deficiencies could be rescued by expression of full-length ATP6AP2. Conditional deletion of Atp6ap2 in developing mouse brain impaired V-ATPase-dependent functions, causing impaired neural stem cell self-renewal, premature neuronal differentiation, and apoptosis resulting in degeneration of nearly the entire cortex. In vitro studies revealed that ATP6AP2 deficiency decreases V-ATPase membrane assembly and increases endosomal-lysosomal fusion. We conclude that ATP6AP2 is a key mediator of V-ATPase-dependent signaling and protein degradation in the developing human central nervous system.
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Affiliation(s)
- Takuo Hirose
- Collège de France, Center for Interdisciplinary Research in Biology, Paris, France
| | - Alfredo Cabrera-Socorro
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - David Chitayat
- Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.,Division of Clinical and Metabolic Genetics and.,Department of Diagnostic Imaging, Division of Pediatric Neuroradiology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Thomas Lemonnier
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Olivier Féraud
- INSERM, UMR 935, ESTeam Paris Sud, SFR André Lwoff, Université Paris Sud, Villejuif, France.,Infrastructure Nationale INGESTEM, Université Paris Sud, INSERM, Paris, France
| | - Carmen Cifuentes-Diaz
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Nicolas Gervasi
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Cedric Mombereau
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Tanay Ghosh
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Loredana Stoica
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Jeanne d'Arc Al Bacha
- Collège de France, Center for Interdisciplinary Research in Biology, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France.,Laboratory of Applied Biotechnology, Azm Center for the Research in Biotechnology and Its Applications, Doctoral School for Sciences and Technology, Lebanese University, Tripoli, Lebanon.,Reviva Regenerative Medicine Center, Human Genetic Center, Middle East Institute of Health Hospital, Bsalim, Lebanon
| | - Hiroshi Yamada
- Department of Neuroscience, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Marcel A Lauterbach
- Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS, UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marc Guillon
- Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS, UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Kiriko Kaneko
- Department of Endocrinology and Applied Medical Science, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Joy W Norris
- Greenwood Genetic Center, Greenwood, South Carolina, USA
| | | | | | - Jérémie Teillon
- Collège de France, Center for Interdisciplinary Research in Biology, Paris, France.,INSERM, U1050, Paris, France.,CNRS, UMR 7241, Paris, France
| | | | - Marion Russeau
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Julien Hadoux
- INSERM, UMR 935, ESTeam Paris Sud, SFR André Lwoff, Université Paris Sud, Villejuif, France.,Infrastructure Nationale INGESTEM, Université Paris Sud, INSERM, Paris, France
| | - Sadayoshi Ito
- Division of Nephrology, Endocrinology and Vascular Medicine, Department of Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Pierre Corvol
- Collège de France, Center for Interdisciplinary Research in Biology, Paris, France.,INSERM, U1050, Paris, France.,CNRS, UMR 7241, Paris, France
| | | | - Kenton R Holden
- Department of Radiology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Kohji Takei
- Department of Neuroscience, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Valentina Emiliani
- Wavefront-Engineering Microscopy Group, Neurophotonics Laboratory, CNRS, UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Annelise Bennaceur-Griscelli
- INSERM, UMR 935, ESTeam Paris Sud, SFR André Lwoff, Université Paris Sud, Villejuif, France.,Infrastructure Nationale INGESTEM, Université Paris Sud, INSERM, Paris, France.,Faculté de Médecine, Kremlin-Bicêtre, Université Paris Sud, Paris Saclay, France.,AP-HP, Service d'Hématologie, Hôpitaux Universitaires Paris Sud, Hôpital Paul Brousse, Villejuif, France
| | | | - Genevieve Nguyen
- Collège de France, Center for Interdisciplinary Research in Biology, Paris, France.,INSERM, U1050, Paris, France.,CNRS, UMR 7241, Paris, France
| | - Matthias Groszer
- INSERM, UMR-S 1270, Paris, France.,Sorbonne Université, Paris, France.,Institut du Fer à Moulin, Paris, France
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23
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Şentürk M, Lin G, Zuo Z, Mao D, Watson E, Mikos AG, Bellen HJ. Ubiquilins regulate autophagic flux through mTOR signalling and lysosomal acidification. Nat Cell Biol 2019; 21:384-396. [PMID: 30804504 PMCID: PMC6534127 DOI: 10.1038/s41556-019-0281-x] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
Abstract
Although the aetiology of amyotrophic lateral sclerosis (ALS) remains poorly understood, impaired proteostasis is a common feature of different forms of ALS. Mutations in genes encoding ubiquilins, UBQLN2 and UBQLN4, cause familial ALS. The role of ubiquilins in proteasomal degradation is well established, but their role in autophagy-lysosomal clearance is poorly defined. Here, we describe a crosstalk between endoplasmic reticulum stress, mTOR signalling and autophagic flux in Drosophila and mammalian cells lacking ubiquilins. We found that loss of ubiquilins leads to endoplasmic reticulum stress, impairs mTORC1 activity, promotes autophagy and causes the demise of neurons. We show that ubiquilin mutants display defective autophagic flux due to reduced lysosome acidification. Ubiquilins are required to maintain proper levels of the V0a/V100 subunit of the vacuolar H+-ATPase and lysosomal pH. Feeding flies acidic nanoparticles alleviates defective autophagic flux in ubiquilin mutants. Hence, our studies reveal a conserved role for ubiquilins as regulators of autophagy by controlling vacuolar H+-ATPase activity and mTOR signalling.
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Affiliation(s)
- Mümine Şentürk
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Guang Lin
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA
| | - Dongxue Mao
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Emma Watson
- Department of Bioengineering, Rice University, Houston, TX, USA
- Medical Scientist Training Program, BCM, Houston, TX, USA
| | - Antonios G Mikos
- Department of Bioengineering, Rice University, Houston, TX, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA.
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA.
- Department of Neuroscience, BCM, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
- Howard Hughes Medical Institute, BCM, Houston, TX, USA.
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24
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Soukup SF, Vanhauwaert R, Verstreken P. Parkinson's disease: convergence on synaptic homeostasis. EMBO J 2018; 37:embj.201898960. [PMID: 30065071 DOI: 10.15252/embj.201898960] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 05/07/2018] [Accepted: 07/06/2018] [Indexed: 01/01/2023] Open
Abstract
Parkinson's disease, the second most common neurodegenerative disorder, affects millions of people globally. There is no cure, and its prevalence will double by 2030. In recent years, numerous causative genes and risk factors for Parkinson's disease have been identified and more than half appear to function at the synapse. Subtle synaptic defects are thought to precede blunt neuronal death, but the mechanisms that are dysfunctional at synapses are only now being unraveled. Here, we review recent work and propose a model where different Parkinson proteins interact in a cell compartment-specific manner at the synapse where these proteins regulate endocytosis and autophagy. While this field is only recently emerging, the work suggests that the loss of synaptic homeostasis may contribute to neurodegeneration and is a key player in Parkinson's disease.
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Affiliation(s)
- Sandra-Fausia Soukup
- VIB-KU Leuven Center for Brain& Disease Research, Leuven, Belgium .,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Roeland Vanhauwaert
- VIB-KU Leuven Center for Brain& Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Patrik Verstreken
- VIB-KU Leuven Center for Brain& Disease Research, Leuven, Belgium .,Department of Neurosciences, KU Leuven, Leuven, Belgium
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25
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Zhao H, Wang J, Wang T. The V-ATPase V1 subunit A1 is required for rhodopsin anterograde trafficking in Drosophila. Mol Biol Cell 2018; 29:1640-1651. [PMID: 29742016 PMCID: PMC6080656 DOI: 10.1091/mbc.e17-09-0546] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Synthesis and maturation of the light sensor, rhodopsin, are critical for the maintenance of light sensitivity and for photoreceptor homeostasis. In Drosophila, the main rhodopsin, Rh1, is synthesized in the endoplasmic reticulum and transported to the rhabdomere through the secretory pathway. In an unbiased genetic screen for factors involved in rhodopsin homeostasis, we identified mutations in vha68-1, which encodes the vacuolar proton-translocating ATPase (V-ATPase) catalytic subunit A isoform 1 of the V1 component. Loss of vha68-1 in photoreceptor cells disrupted post-Golgi anterograde trafficking of Rh1, reduced light sensitivity, increased secretory vesicle pH, and resulted in incomplete Rh1 deglycosylation. In addition, vha68-1 was required for activity-independent photoreceptor cell survival. Importantly, vha68-1 mutants exhibited phenotypes similar to those exhibited by mutations in the V0 component of V-ATPase, vha100-1. These data demonstrate that the V1 and V0 components of V-ATPase play key roles in post-Golgi trafficking of Rh1 and that Drosophila may represent an important animal model system for studying diseases associated with V-ATPase dysfunction.
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Affiliation(s)
- Haifang Zhao
- School of Life Sciences, Tsinghua University, Beijing 100084, China.,National Institute of Biological Sciences, Beijing 102206, China
| | - Jing Wang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Tao Wang
- National Institute of Biological Sciences, Beijing 102206, China
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26
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Yan P, Sun X, Chen X, Chen Y, Wang X, Su D, Zhou H, Gao L, Lu L, Wang J, Zhang J. The Polyphenolic Compound Curcumin Conjugation with an Alkyne Moiety in the Process of Autophagy. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2018; 46:673-687. [PMID: 29614882 DOI: 10.1142/s0192415x18500350] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Curcumin is a hydrophobic polyphenol derived from turmeric: the rhizome of the herb Curcumalonga. Autophagy is an evolutionarily conserved process, in which cellular proteins and organelles are engulfed in autophagosome and then fuses with lysosome for degradation. Our previous study showed that Curcumin activates lysosome and induce autophagy through inhibition of AKT (protein kinase K, PKB)-mammalian target of rapamycin (mTOR) pathway. But whether Curucmin affects the fusion of autophagosome-lysosome is still not clear. Here, we used Curcumin-probe conjugation with an alkyne moiety to label mouse embryonic fibroblasts (MEFs) and found that Curcumin targets autophagy-related proteins, enhances autophagic flux and activates lysosome in cells. Moreover, Curcumin treatment promotes the fusion of autophasosome-lysosome in MEFs. Second, the enhanced fusion of autophagosome-lysosome is attributed to mTOR suppression. Third, blockage of the autophagosome-lysosome fusion leads to cell growth inhibition by Curcumin. Taken together, data from our study indicates the importance of the fusion of autophagosome-lysosome in Curcumin-induced autophagy, which may facilitate the development of Curcumin as a potential therapeutic agent for oxidative stress-related diseases.
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Affiliation(s)
- Peiyi Yan
- Department of Clinical Laboratory, Shanghai Putuo District People’s Hospital, Shanghai, China
| | - Xin Sun
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Xiaochen Chen
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Yun Chen
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Xiao Wang
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Dan Su
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Hongying Zhou
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Liang Gao
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Liqin Lu
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
| | - Jigang Wang
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jianbin Zhang
- Department of Oncology, Clinical Research Institute, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, China
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27
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Jin EJ, Kiral FR, Ozel MN, Burchardt LS, Osterland M, Epstein D, Wolfenberg H, Prohaska S, Hiesinger PR. Live Observation of Two Parallel Membrane Degradation Pathways at Axon Terminals. Curr Biol 2018; 28:1027-1038.e4. [PMID: 29551411 PMCID: PMC5944365 DOI: 10.1016/j.cub.2018.02.032] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/24/2018] [Accepted: 02/14/2018] [Indexed: 01/04/2023]
Abstract
Neurons are highly polarized cells that require continuous turnover of membrane proteins at axon terminals to develop, function, and survive. Yet, it is still unclear whether membrane protein degradation requires transport back to the cell body or whether degradation also occurs locally at the axon terminal, where live observation of sorting and degradation has remained a challenge. Here, we report direct observation of two cargo-specific membrane protein degradation mechanisms at axon terminals based on a live-imaging approach in intact Drosophila brains. We show that different acidification-sensing cargo probes are sorted into distinct classes of degradative “hub” compartments for synaptic vesicle proteins and plasma membrane proteins at axon terminals. Sorting and degradation of the two cargoes in the separate hubs are molecularly distinct. Local sorting of synaptic vesicle proteins for degradation at the axon terminal is, surprisingly, Rab7 independent, whereas sorting of plasma membrane proteins is Rab7 dependent. The cathepsin-like protease CP1 is specific to synaptic vesicle hubs, and its delivery requires the vesicle SNARE neuronal synaptobrevin. Cargo separation only occurs at the axon terminal, whereas degradative compartments at the cell body are mixed. These data show that at least two local, molecularly distinct pathways sort membrane cargo for degradation specifically at the axon terminal, whereas degradation can occur both at the terminal and en route to the cell body.
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Affiliation(s)
- Eugene Jennifer Jin
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany; Graduate School of Biomedical Sciences, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ferdi Ridvan Kiral
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany
| | - Mehmet Neset Ozel
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany; Graduate School of Biomedical Sciences, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lara Sophie Burchardt
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany
| | - Marc Osterland
- Zuse Institute Berlin, Takustraße 7, 14195 Berlin, Germany
| | - Daniel Epstein
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany
| | - Heike Wolfenberg
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany
| | | | - Peter Robin Hiesinger
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany.
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28
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Jin EJ, Kiral FR, Hiesinger PR. The where, what, and when of membrane protein degradation in neurons. Dev Neurobiol 2018; 78:283-297. [PMID: 28884504 PMCID: PMC5816708 DOI: 10.1002/dneu.22534] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 12/20/2022]
Abstract
Membrane protein turnover and degradation are required for the function and health of all cells. Neurons may live for the entire lifetime of an organism and are highly polarized cells with spatially segregated axonal and dendritic compartments. Both longevity and morphological complexity represent challenges for regulated membrane protein degradation. To investigate how neurons cope with these challenges, an increasing number of recent studies investigated local, cargo-specific protein sorting, and degradation at axon terminals and in dendritic processes. In this review, we explore the current answers to the ensuing questions of where, what, and when membrane proteins are degraded in neurons. © 2017 The Authors Developmental Neurobiology Published by Wiley Periodicals, Inc. Develop Neurobiol 78: 283-297, 2018.
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Affiliation(s)
- Eugene Jennifer Jin
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
- Graduate School of Biomedical SciencesUniversity of Texas Southwestern Medical CenterDallasTX75390USA
| | - Ferdi Ridvan Kiral
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
| | - Peter Robin Hiesinger
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
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29
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Perry M, Konstantinides N, Pinto-Teixeira F, Desplan C. Generation and Evolution of Neural Cell Types and Circuits: Insights from the Drosophila Visual System. Annu Rev Genet 2017; 51:501-527. [PMID: 28961025 DOI: 10.1146/annurev-genet-120215-035312] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The Drosophila visual system has become a premier model for probing how neural diversity is generated during development. Recent work has provided deeper insight into the elaborate mechanisms that control the range of types and numbers of neurons produced, which neurons survive, and how they interact. These processes drive visual function and influence behavioral preferences. Other studies are beginning to provide insight into how neuronal diversity evolved in insects by adding new cell types and modifying neural circuits. Some of the most powerful comparisons have been those made to the Drosophila visual system, where a deeper understanding of molecular mechanisms allows for the generation of hypotheses about the evolution of neural anatomy and function. The evolution of new neural types contributes additional complexity to the brain and poses intriguing questions about how new neurons interact with existing circuitry. We explore how such individual changes in a variety of species might play a role over evolutionary timescales. Lessons learned from the fly visual system apply to other neural systems, including the fly central brain, where decisions are made and memories are stored.
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Affiliation(s)
- Michael Perry
- Department of Biology, New York University, New York, NY 10003, USA;
| | | | - Filipe Pinto-Teixeira
- Department of Biology, New York University, New York, NY 10003, USA; .,Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | - Claude Desplan
- Department of Biology, New York University, New York, NY 10003, USA; .,Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
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30
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Bhattacharya S, Yin J, Winborn CS, Zhang Q, Yue J, Chaum E. Prominin-1 Is a Novel Regulator of Autophagy in the Human Retinal Pigment Epithelium. Invest Ophthalmol Vis Sci 2017; 58:2366-2387. [PMID: 28437526 PMCID: PMC5403116 DOI: 10.1167/iovs.16-21162] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Purpose Prominin-1 (Prom1) is a transmembrane glycoprotein, which is expressed in stem cell lineages, and has recently been implicated in cancer stem cell survival. Mutations in the Prom1 gene have been shown to disrupt photoreceptor disk morphogenesis and cause an autosomal dominant form of Stargardt-like macular dystrophy (STGD4). Despite the apparent structural role of Prom1 in photoreceptors, its role in other cells of the retina is unknown. The purpose of this study is to investigate the role of Prom1 in the highly metabolically active cells of the retinal pigment epithelium (RPE). Methods Lentiviral siRNA and the genome editing CRISPR/Cas9 system were used to knockout Prom1 in primary RPE and ARPE-19 cells, respectively. Western blotting, confocal microscopy, and flow sight imaging cytometry assays were used to quantify autophagy flux. Immunoprecipitation was used to detect Prom1 interacting proteins. Results Our studies demonstrate that Prom1 is primarily a cytosolic protein in the RPE. Stress signals and physiological aging robustly increase autophagy with concomitant upregulation of Prom1 expression. Knockout of Prom1 increased mTORC1 and mTORC2 signaling, decreased autophagosome trafficking to the lysosome, increased p62 accumulation, and inhibited autophagic puncta induced by activators of autophagy. Conversely, ectopic overexpression of Prom1 inhibited mTORC1 and mTORC2 activities, and potentiated autophagy flux. Through interactions with p62 and HDAC6, Prom1 regulates autophagosome maturation and trafficking, suggesting a new cytoplasmic role of Prom1 in RPE function. Conclusions Our results demonstrate that Prom1 plays a key role in the regulation of autophagy via upstream suppression of mTOR signaling and also acting as a component of a macromolecular scaffold involving p62 and HDAC6.
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Affiliation(s)
- Sujoy Bhattacharya
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Jinggang Yin
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Christina S Winborn
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Qiuhua Zhang
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Junming Yue
- Department of Pathology, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Edward Chaum
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States 3Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee, United States
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Yoshizaki N, Hashizume R, Masaki H. A polymethoxyflavone mixture extracted from orange peels, mainly containing nobiletin, 3,3',4',5,6,7,8-heptamethoxyflavone and tangeretin, suppresses melanogenesis through the acidification of cell organelles, including melanosomes. J Dermatol Sci 2017. [PMID: 28629701 DOI: 10.1016/j.jdermsci.2017.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Skin color is determined by melanin contents and its distribution. Melanin is synthesized in melanosomes of melanocytes, catalyzed by tyrosinase, melanogenic enzymes. Regarding the process of melanin synthesis, melanosomal pH is considered to play an important role, because it has been reported to differ between Caucasian and Black melanocytes. OBJECTIVE Although polymethoxyflavone (PMF) has many beneficial effects, it has not been reported which PMF suppresses melanogenesis. In this study, we identified the mechanism underlying the effect of PMF on melanogenesis METHODS: We determined the effects of a PMF mixture extracted from orange peels on melanogenesis, on tyrosinase expression, on the localization of tyrosinase and on the acidification of organelles, including melanosomes, in HM3KO human melanoma cells. RESULTS TREATMENT: with the PMF mixture elicited the suppression of melanogenesis, the degradation of tyrosinase in lysosomes and the mislocalization of tyrosinase associated with the acidification of intracellular organelles, including melanosomes. The neutralization of cell organelle pH by ammonium chloride restored melanogenesis and the correct localization of tyrosinase to melanosomes, which had been suppressed by the PMF mixture. CONCLUSION These results suggest that the PMF mixture suppresses the localization of tyrosinase to melanosomes and consequently inhibits melanogenesis due to the acidification of cell organelles, including melanosomes.
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Affiliation(s)
- Norihiro Yoshizaki
- Advanced Technology Research Laboratory, NOF Corporation, 5-10 Tokodai, Tsukuba, Ibaraki 300-2635, Japan.
| | - Ron Hashizume
- Advanced Technology Research Laboratory, NOF Corporation, 5-10 Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Hitoshi Masaki
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1, Katakura-machi, Hachioji-shi, Tokyo 192-0982, Japan
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Braidy N, Poljak A, Marjo C, Rutlidge H, Rich A, Jugder BE, Jayasena T, Inestrosa NC, Sachdev PS. Identification of Cerebral Metal Ion Imbalance in the Brain of Aging Octodon degus. Front Aging Neurosci 2017; 9:66. [PMID: 28405187 PMCID: PMC5370394 DOI: 10.3389/fnagi.2017.00066] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 03/03/2017] [Indexed: 01/18/2023] Open
Abstract
The accumulation of redox-active transition metals in the brain and metal dyshomeostasis are thought to be associated with the etiology and pathogenesis of several neurodegenerative diseases, and Alzheimer’s disease (AD) in particular. As well, distinct biometal imaging and role of metal uptake transporters are central to understanding AD pathogenesis and aging but remain elusive, due inappropriate detection methods. We therefore hypothesized that Octodon degus develop neuropathological abnormalities in the distribution of redox active biometals, and this effect may be due to alterations in the expression of lysosomal protein, major Fe/Cu transporters, and selected Zn transporters (ZnTs and ZIPs). Herein, we report the distribution profile of biometals in the aged brain of the endemic Chilean rodent O. degus—a natural model to investigate the role of metals on the onset and progression of AD. Using laser ablation inductively coupled plasma mass spectrometry, our quantitative images of biometals (Fe, Ca, Zn, Cu, and Al) appear significantly elevated in the aged O. degus and show an age-dependent rise. The metals Fe, Ca, Zn, and Cu were specifically enriched in the cortex and hippocampus, which are the regions where amyloid plaques, tau phosphorylation and glial alterations are most commonly reported, whilst Al was enriched in the hippocampus alone. Using whole brain extracts, age-related deregulation of metal trafficking pathways was also observed in O. degus. More specifically, we observed impaired lysosomal function, demonstrated by increased cathepsin D protein expression. An age-related reduction in the expression of subunit B2 of V-ATPase, and significant increases in amyloid beta peptide 42 (Aβ42), and the metal transporter ATP13a2 were also observed. Although the protein expression levels of the zinc transporters, ZnT (1,3,4,6, and 7), and ZIP7,8 and ZIP14 increased in the brain of aged O. degus, ZnT10, decreased. Although no significant age-related change was observed for the major iron/copper regulator IRP2, we did find a significant increase in the expression of DMT1, a major transporter of divalent metal species, 5′-aminolevulinate synthase 2 (ALAS2), and the proto-oncogene, FOS. Collectively, our data indicate that transition metals may be enriched with age in the brains of O. degus, and metal dyshomeostasis in specific brain regions is age-related.
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Affiliation(s)
- Nady Braidy
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia
| | - Anne Poljak
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South WalesSydney, NSW, Australia; Mark Wainwright Analytical Centre, University of New South WalesSydney, NSW, Australia; School of Medical Sciences, Faculty of Medicine, University of New South WalesSydney, NSW, Australia
| | - Chris Marjo
- Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Helen Rutlidge
- Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Anne Rich
- Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Bat-Erdene Jugder
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales Sydney, NSW, Australia
| | - Tharusha Jayasena
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia
| | - Nibaldo C Inestrosa
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South WalesSydney, NSW, Australia; Centre for Ageing and Regeneration, Faculty of Biological Sciences, Pontifical Catholic University of ChileSantiago, Chile
| | - Perminder S Sachdev
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South WalesSydney, NSW, Australia; Neuropsychiatric Institute, Euroa Centre, Prince of Wales HospitalSydney, NSW, Australia
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Vanhauwaert R, Kuenen S, Masius R, Bademosi A, Manetsberger J, Schoovaerts N, Bounti L, Gontcharenko S, Swerts J, Vilain S, Picillo M, Barone P, Munshi ST, de Vrij FM, Kushner SA, Gounko NV, Mandemakers W, Bonifati V, Meunier FA, Soukup SF, Verstreken P. The SAC1 domain in synaptojanin is required for autophagosome maturation at presynaptic terminals. EMBO J 2017; 36:1392-1411. [PMID: 28331029 DOI: 10.15252/embj.201695773] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 02/25/2017] [Accepted: 03/01/2017] [Indexed: 11/09/2022] Open
Abstract
Presynaptic terminals are metabolically active and accrue damage through continuous vesicle cycling. How synapses locally regulate protein homeostasis is poorly understood. We show that the presynaptic lipid phosphatase synaptojanin is required for macroautophagy, and this role is inhibited by the Parkinson's disease mutation R258Q. Synaptojanin drives synaptic endocytosis by dephosphorylating PI(4,5)P2, but this function appears normal in SynaptojaninRQ knock-in flies. Instead, R258Q affects the synaptojanin SAC1 domain that dephosphorylates PI(3)P and PI(3,5)P2, two lipids found in autophagosomal membranes. Using advanced imaging, we show that SynaptojaninRQ mutants accumulate the PI(3)P/PI(3,5)P2-binding protein Atg18a on nascent synaptic autophagosomes, blocking autophagosome maturation at fly synapses and in neurites of human patient induced pluripotent stem cell-derived neurons. Additionally, we observe neurodegeneration, including dopaminergic neuron loss, in SynaptojaninRQ flies. Thus, synaptojanin is essential for macroautophagy within presynaptic terminals, coupling protein turnover with synaptic vesicle cycling and linking presynaptic-specific autophagy defects to Parkinson's disease.
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Affiliation(s)
- Roeland Vanhauwaert
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Sabine Kuenen
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Roy Masius
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Adekunle Bademosi
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Julia Manetsberger
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Nils Schoovaerts
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Laura Bounti
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Serguei Gontcharenko
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Jef Swerts
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Sven Vilain
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Marina Picillo
- Department of Medicine and Surgery, Center for Neurodegenerative Diseases (CEMAND), University of Salerno, Salerno, Italy
| | - Paolo Barone
- Department of Medicine and Surgery, Center for Neurodegenerative Diseases (CEMAND), University of Salerno, Salerno, Italy
| | | | - Femke Ms de Vrij
- Department of Psychiatry, Erasmus MC, Rotterdam, The Netherlands
| | - Steven A Kushner
- Department of Psychiatry, Erasmus MC, Rotterdam, The Netherlands
| | - Natalia V Gounko
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium.,Electron Microscopy Platform, VIB Bio-Imaging Core, Leuven, Belgium
| | - Wim Mandemakers
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Vincenzo Bonifati
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Frederic A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Sandra-Fausia Soukup
- VIB Center for Brain & Disease Research, Leuven, Belgium .,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Patrik Verstreken
- VIB Center for Brain & Disease Research, Leuven, Belgium .,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
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Colacurcio DJ, Nixon RA. Disorders of lysosomal acidification-The emerging role of v-ATPase in aging and neurodegenerative disease. Ageing Res Rev 2016; 32:75-88. [PMID: 27197071 DOI: 10.1016/j.arr.2016.05.004] [Citation(s) in RCA: 314] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/02/2016] [Accepted: 05/13/2016] [Indexed: 12/21/2022]
Abstract
Autophagy and endocytosis deliver unneeded cellular materials to lysosomes for degradation. Beyond processing cellular waste, lysosomes release metabolites and ions that serve signaling and nutrient sensing roles, linking the functions of the lysosome to various pathways for intracellular metabolism and nutrient homeostasis. Each of these lysosomal behaviors is influenced by the intraluminal pH of the lysosome, which is maintained in the low acidic range by a proton pump, the vacuolar ATPase (v-ATPase). New reports implicate altered v-ATPase activity and lysosomal pH dysregulation in cellular aging, longevity, and adult-onset neurodegenerative diseases, including forms of Parkinson disease and Alzheimer disease. Genetic defects of subunits composing the v-ATPase or v-ATPase-related proteins occur in an increasingly recognized group of familial neurodegenerative diseases. Here, we review the expanding roles of the v-ATPase complex as a platform regulating lysosomal hydrolysis and cellular homeostasis. We discuss the unique vulnerability of neurons to persistent low level lysosomal dysfunction and review recent clinical and experimental studies that link dysfunction of the v-ATPase complex to neurodegenerative diseases across the age spectrum.
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35
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Soukup SF, Kuenen S, Vanhauwaert R, Manetsberger J, Hernández-Díaz S, Swerts J, Schoovaerts N, Vilain S, Gounko NV, Vints K, Geens A, De Strooper B, Verstreken P. A LRRK2-Dependent EndophilinA Phosphoswitch Is Critical for Macroautophagy at Presynaptic Terminals. Neuron 2016; 92:829-844. [PMID: 27720484 DOI: 10.1016/j.neuron.2016.09.037] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 07/04/2016] [Accepted: 09/15/2016] [Indexed: 11/18/2022]
Abstract
Synapses are often far from the soma and independently cope with proteopathic stress induced by intense neuronal activity. However, how presynaptic compartments turn over proteins is poorly understood. We show that the synapse-enriched protein EndophilinA, thus far studied for its role in endocytosis, induces macroautophagy at presynaptic terminals. We find that EndophilinA executes this unexpected function at least partly independent of its role in synaptic vesicle endocytosis. EndophilinA-induced macroautophagy is activated when the kinase LRRK2 phosphorylates the EndophilinA-BAR domain and is blocked in animals where EndophilinA cannot be phosphorylated. EndophilinA-phosphorylation promotes the formation of highly curved membranes, and reconstitution experiments show these curved membranes serve as docking stations for autophagic factors, including Atg3. Functionally, deregulation of the EndophilinA phosphorylation state accelerates activity-induced neurodegeneration. Given that EndophilinA is connected to at least three Parkinson's disease genes (LRRK2, Parkin and Synaptojanin), dysfunction of EndophilinA-dependent synaptic macroautophagy may be common in this disorder.
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Affiliation(s)
- Sandra-Fausia Soukup
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Sabine Kuenen
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Roeland Vanhauwaert
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Julia Manetsberger
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Sergio Hernández-Díaz
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Jef Swerts
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Nils Schoovaerts
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Sven Vilain
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Natalia V Gounko
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Katlijn Vints
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Ann Geens
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Bart De Strooper
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium
| | - Patrik Verstreken
- VIB Center for Brain & Disease Research, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease, 3000 Leuven, Belgium.
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Organelle acidification negatively regulates vacuole membrane fusion in vivo. Sci Rep 2016; 6:29045. [PMID: 27363625 PMCID: PMC4929563 DOI: 10.1038/srep29045] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 06/10/2016] [Indexed: 12/13/2022] Open
Abstract
The V-ATPase is a proton pump consisting of a membrane-integral V0 sector and a peripheral V1 sector, which carries the ATPase activity. In vitro studies of yeast vacuole fusion and evidence from worms, flies, zebrafish and mice suggested that V0 interacts with the SNARE machinery for membrane fusion, that it promotes the induction of hemifusion and that this activity requires physical presence of V0 rather than its proton pump activity. A recent in vivo study in yeast has challenged these interpretations, concluding that fusion required solely lumenal acidification but not the V0 sector itself. Here, we identify the reasons for this discrepancy and reconcile it. We find that acute pharmacological or physiological inhibition of V-ATPase pump activity de-acidifies the vacuole lumen in living yeast cells within minutes. Time-lapse microscopy revealed that de-acidification induces vacuole fusion rather than inhibiting it. Cells expressing mutated V0 subunits that maintain vacuolar acidity were blocked in this fusion. Thus, proton pump activity of the V-ATPase negatively regulates vacuole fusion in vivo. Vacuole fusion in vivo does, however, require physical presence of a fusion-competent V0 sector.
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Stenesen D, Moehlman AT, Krämer H. The carcinine transporter CarT is required in Drosophila photoreceptor neurons to sustain histamine recycling. eLife 2015; 4:e10972. [PMID: 26653853 PMCID: PMC4739767 DOI: 10.7554/elife.10972] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/13/2015] [Indexed: 12/30/2022] Open
Abstract
Synaptic transmission from Drosophila photoreceptors to lamina neurons requires recycling of histamine neurotransmitter. Synaptic histamine is cleared by uptake into glia and conversion into carcinine, which functions as transport metabolite. How carcinine is transported from glia to photoreceptor neurons remains unclear. In a targeted RNAi screen for genes involved in this pathway, we identified carT, which encodes a member of the SLC22A transporter family. CarT expression in photoreceptors is necessary and sufficient for fly vision and behavior. Carcinine accumulates in the lamina of carT flies. Wild-type levels are restored by photoreceptor-specific expression of CarT, and endogenous tagging suggests CarT localizes to synaptic endings. Heterologous expression of CarT in S2 cells is sufficient for carcinine uptake, demonstrating the ability of CarT to utilize carcinine as a transport substrate. Together, our results demonstrate that CarT transports the histamine metabolite carcinine into photoreceptor neurons, thus contributing an essential step to the histamine–carcinine cycle. DOI:http://dx.doi.org/10.7554/eLife.10972.001 Photoreceptors are light-sensitive neurons in the eyes of the fruit fly Drosophila that form connections with other neurons in the fly’s brain. At these connections, which are called synapses, the photoreceptors continuously release a chemical called histamine. Photoreceptors will release more or less histamine depending on changes in light intensity, but always tend to release more histamine than they can produce themselves from scratch. This means that the visual system in Drosophila relies on a pathway that recycles histamine. That is to say, glial cells (which support the activity of the neurons) remove the chemical from synapses and return it to the photoreceptor neurons in a slightly modified form called “carcinine”. The photoreceptors then quickly convert the chemical back into histamine, ready to be released. Stenesen et al. set out to identify the proteins that support this recycling pathway, and started by screening around 130 genes that encode transporter proteins for potential roles in histamine recycling. This screen identified a gene encoding a protein that was named CarT. This protein transports carcinine, the modified version of the histamine neurotransmitter. Stenesen et al. show that the photoreceptor neurons make the CarT protein and need this protein to take up the carcinine released by the supporting glial cells. Without CarT, photoreceptor neurons cannot transmit visual information, and so mutant flies in which the gene for CarT is deleted are blind. Follow-up studies related to this work could involve identifying the transporters that move histamine and carcinine in and out of the glia cells, and exploring what other neurons and behaviors in fruit flies rely on CarT’s activity. DOI:http://dx.doi.org/10.7554/eLife.10972.002
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Affiliation(s)
- Drew Stenesen
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States
| | - Andrew T Moehlman
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States
| | - Helmut Krämer
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States
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38
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Morel N, Poëa-Guyon S. The membrane domain of vacuolar H(+)ATPase: a crucial player in neurotransmitter exocytotic release. Cell Mol Life Sci 2015; 72:2561-73. [PMID: 25795337 PMCID: PMC11113229 DOI: 10.1007/s00018-015-1886-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/10/2015] [Accepted: 03/12/2015] [Indexed: 12/31/2022]
Abstract
V-ATPases are multimeric enzymes made of two sectors, a V1 catalytic domain and a V0 membrane domain. They accumulate protons in various intracellular organelles. Acidification of synaptic vesicles by V-ATPase energizes the accumulation of neurotransmitters in these storage organelles and is therefore required for efficient synaptic transmission. In addition to this well-accepted role, functional studies have unraveled additional hidden roles of V0 in neurotransmitter exocytosis that are independent of the transport of protons. V0 interacts with SNAREs and calmodulin, and perturbing these interactions affects neurotransmitter release. Here, we discuss these data in relation with previous results obtained in reconstituted membranes and on yeast vacuole fusion. We propose that V0 could be a sensor of intra-vesicular pH that controls the exocytotic machinery, probably regulating SNARE complex assembly during the synaptic vesicle priming step, and that, during the membrane fusion step, V0 might favor lipid mixing and fusion pore stability.
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Affiliation(s)
- Nicolas Morel
- Centre de Neurosciences Paris-Sud, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8195 and Université Paris-Sud, 91405, Orsay, France,
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Lőrincz P, Takáts S, Kárpáti M, Juhász G. iFly: The eye of the fruit fly as a model to study autophagy and related trafficking pathways. Exp Eye Res 2015; 144:90-8. [PMID: 26091788 DOI: 10.1016/j.exer.2015.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 05/28/2015] [Accepted: 06/15/2015] [Indexed: 12/21/2022]
Abstract
Autophagy is a process by which eukaryotic cells degrade and recycle their intracellular components within lysosomes. Autophagy is induced by starvation to ensure survival of individual cells, and it has evolved to fulfill numerous additional roles in animals. Autophagy not only provides nutrient supply through breakdown products during starvation, but it is also required for the elimination of damaged or surplus organelles, toxic proteins, aggregates, and pathogens, and is essential for normal organelle turnover. Because of these roles, defects in autophagy have pathological consequences. Here we summarize the current knowledge of autophagy and related trafficking pathways in a convenient model: the compound eye of the fruit fly Drosophila melanogaster. In our review, we present a general introduction of the development and structure of the compound eye. This is followed by a discussion of various neurodegeneration models including retinopathies, with special emphasis on the protective role of autophagy against these diseases.
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Affiliation(s)
- Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary
| | - Szabolcs Takáts
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary
| | - Manuéla Kárpáti
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary; Momentum Drosophila Autophagy Research Group, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, Szeged H-6726, Hungary.
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Francis D, Ghabrial AS. Compensatory branching morphogenesis of stalk cells in the Drosophila trachea. Development 2015; 142:2048-57. [PMID: 25977367 DOI: 10.1242/dev.119602] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 04/16/2015] [Indexed: 01/11/2023]
Abstract
Tubes are essential for nutrient transport and gas exchange in multicellular eukaryotes, but how connections between different tube types are maintained over time is unknown. In the Drosophila tracheal system, mutations in oak gall (okg) and conjoined (cnj) confer identical defects, including late onset blockage near the terminal cell-stalk cell junction and the ectopic extension of autocellular, seamed tubes into the terminal cell. We determined that okg and cnj encode the E and G subunits of the vacuolar ATPase (vATPase) and showed that both the V0 and V1 domains are required for terminal cell morphogenesis. Remarkably, the ectopic seamed tubes running along vATPase-deficient terminal cells belonged to the neighboring stalk cells. All vATPase-deficient tracheal cells had reduced apical domains and terminal cells displayed mislocalized apical proteins. Consistent with recent reports that the mTOR and vATPase pathways intersect, we found that mTOR pathway mutants phenocopied okg and cnj. Furthermore, terminal cells depleted for the apical determinants Par6 or aPKC had identical ectopic seamed tube defects. We thus identify a novel mechanism of compensatory branching in which stalk cells extend autocellular tubes into neighboring terminal cells with undersized apical domains. This compensatory branching also occurs in response to injury, with damaged terminal cells being rapidly invaded by their stalk cell neighbor.
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Affiliation(s)
- Deanne Francis
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Amin S Ghabrial
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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Mauvezin C, Nagy P, Juhász G, Neufeld TP. Autophagosome-lysosome fusion is independent of V-ATPase-mediated acidification. Nat Commun 2015; 6:7007. [PMID: 25959678 PMCID: PMC4428688 DOI: 10.1038/ncomms8007] [Citation(s) in RCA: 288] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 03/23/2015] [Indexed: 12/20/2022] Open
Abstract
The ATP-dependent proton pump V-ATPase ensures low intralysosomal pH, which is essential for lysosomal hydrolase activity. Based on studies with the V-ATPase inhibitor BafilomycinA1, lysosomal acidification is also thought to be required for fusion with incoming vesicles from the autophagic and endocytic pathways. Here we show that loss of V-ATPase subunits in the Drosophila fat body causes an accumulation of non-functional lysosomes, leading to a block in autophagic flux. However, V-ATPase-deficient lysosomes remain competent to fuse with autophagosomes and endosomes, resulting in a time-dependent formation of giant autolysosomes. In contrast, BafilomycinA1 prevents autophagosome–lysosome fusion in these cells, and this defect is phenocopied by depletion of the Ca2+ pump SERCA, a secondary target of this drug. Moreover, activation of SERCA promotes fusion in a BafilomycinA1-sensitive manner. Collectively, our results indicate that lysosomal acidification is not a prerequisite for fusion, and that BafilomycinA1 inhibits fusion independent of its effect on lysosomal pH. BafilomycinA1 is an autophagy inhibitor, presumably owing to its blocking effect on the lysosomal proton pump V-ATPase. Here the authors show that V-ATPase-deficient lysosomes can still fuse with autophagosomes, showing that lysosomal acidification and fusion are two separable, independent events.
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Affiliation(s)
- Caroline Mauvezin
- Department of Genetics, Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455, USA
| | - Péter Nagy
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pazmany s. 1/C. 6.520, Budapest H-1117, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pazmany s. 1/C. 6.520, Budapest H-1117, Hungary
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455, USA
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Tian X, Gala U, Zhang Y, Shang W, Nagarkar Jaiswal S, di Ronza A, Jaiswal M, Yamamoto S, Sandoval H, Duraine L, Sardiello M, Sillitoe RV, Venkatachalam K, Fan H, Bellen HJ, Tong C. A voltage-gated calcium channel regulates lysosomal fusion with endosomes and autophagosomes and is required for neuronal homeostasis. PLoS Biol 2015; 13:e1002103. [PMID: 25811491 PMCID: PMC4374850 DOI: 10.1371/journal.pbio.1002103] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 02/11/2015] [Indexed: 01/03/2023] Open
Abstract
Autophagy helps deliver sequestered intracellular cargo to lysosomes for proteolytic degradation and thereby maintains cellular homeostasis by preventing accumulation of toxic substances in cells. In a forward mosaic screen in Drosophila designed to identify genes required for neuronal function and maintenance, we identified multiple cacophony (cac) mutant alleles. They exhibit an age-dependent accumulation of autophagic vacuoles (AVs) in photoreceptor terminals and eventually a degeneration of the terminals and surrounding glia. cac encodes an α1 subunit of a Drosophila voltage-gated calcium channel (VGCC) that is required for synaptic vesicle fusion with the plasma membrane and neurotransmitter release. Here, we show that cac mutant photoreceptor terminals accumulate AV-lysosomal fusion intermediates, suggesting that Cac is necessary for the fusion of AVs with lysosomes, a poorly defined process. Loss of another subunit of the VGCC, α2δ or straightjacket (stj), causes phenotypes very similar to those caused by the loss of cac, indicating that the VGCC is required for AV-lysosomal fusion. The role of VGCC in AV-lysosomal fusion is evolutionarily conserved, as the loss of the mouse homologues, Cacna1a and Cacna2d2, also leads to autophagic defects in mice. Moreover, we find that CACNA1A is localized to the lysosomes and that loss of lysosomal Cacna1a in cerebellar cultured neurons leads to a failure of lysosomes to fuse with endosomes and autophagosomes. Finally, we show that the lysosomal CACNA1A but not the plasma-membrane resident CACNA1A is required for lysosomal fusion. In summary, we present a model in which the VGCC plays a role in autophagy by regulating the fusion of AVs with lysosomes through its calcium channel activity and hence functions in maintaining neuronal homeostasis. A voltage-gated calcium channel required for neurotransmitter release also regulates the fusion of neuronal lysosomes with endosomes and autophagosomes, thereby helping to maintain cellular homeostasis. Autophagy is a cellular process used by cells to prevent the accumulation of toxic substances. It delivers misfolded proteins and damaged organelles by fusing autophagosomes—organelles formed by a double membrane that surrounds the “debris” to be eliminated—with lysosomes. How this fusion process is regulated during autophagy, however, remains to be established. Here, we analyze this process in flies and mice, and find that loss of different subunits of a specific type of Voltage Gated Calcium Channel (VGCC) leads to defects in lysosomal fusion with autophagosomes in neurons. It was already known that VGCCs control calcium entry at synaptic terminals to promote the fusion of synaptic vesicles with the plasma membrane, and that mutations in the subunits of VGCCs in humans cause neurological diseases. Our data indicate that defects in autophagy and lysosomal fusion are independent of defects in synaptic vesicle fusion and neurotransmitter release, and we show that a specific VGCC is present on lysosomal membranes where it is required for lysosomal fusion with endosomes and autophagosomes. These observations suggest that the fusion events required in autophagy rely on mechanisms similar to those that trigger the fusion of synaptic vesicles with the presynaptic membrane.
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Affiliation(s)
- Xuejun Tian
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Upasana Gala
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yongping Zhang
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Weina Shang
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Sonal Nagarkar Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alberto di Ronza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Marco Sardiello
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Roy V. Sillitoe
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kartik Venkatachalam
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, Texas, United States of America
| | - Hengyu Fan
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (CT), (HJB)
| | - Chao Tong
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
- * E-mail: (CT), (HJB)
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Vibrio effector protein VopQ inhibits fusion of V-ATPase-containing membranes. Proc Natl Acad Sci U S A 2014; 112:100-5. [PMID: 25453092 DOI: 10.1073/pnas.1413764111] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vesicle fusion governs many important biological processes, and imbalances in the regulation of membrane fusion can lead to a variety of diseases such as diabetes and neurological disorders. Here we show that the Vibrio parahaemolyticus effector protein VopQ is a potent inhibitor of membrane fusion based on an in vitro yeast vacuole fusion model. Previously, we demonstrated that VopQ binds to the V(o) domain of the conserved V-type H(+)-ATPase (V-ATPase) found on acidic compartments such as the yeast vacuole. VopQ forms a nonspecific, voltage-gated membrane channel of 18 Å resulting in neutralization of these compartments. We now present data showing that VopQ inhibits yeast vacuole fusion. Furthermore, we identified a unique mutation in VopQ that delineates its two functions, deacidification and inhibition of membrane fusion. The use of VopQ as a membrane fusion inhibitor in this manner now provides convincing evidence that vacuole fusion occurs independently of luminal acidification in vitro.
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Nandi N, Tyra LK, Stenesen D, Krämer H. Acinus integrates AKT1 and subapoptotic caspase activities to regulate basal autophagy. ACTA ACUST UNITED AC 2014; 207:253-68. [PMID: 25332163 PMCID: PMC4210446 DOI: 10.1083/jcb.201404028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
How cellular stresses up-regulate autophagy is not fully understood. One potential regulator is the Drosophila melanogaster protein Acinus (Acn), which is necessary for autophagy induction and triggers excess autophagy when overexpressed. We show that cell type-specific regulation of Acn depends on proteolysis by the caspase Dcp-1. Basal Dcp-1 activity in developing photoreceptors is sufficient for this cleavage without a need for apoptosis to elevate caspase activity. On the other hand, Acn was stabilized by loss of Dcp-1 function or by the presence of a mutation in Acn that eliminates its conserved caspase cleavage site. Acn stability also was regulated by AKT1-mediated phosphorylation. Flies that expressed stabilized forms of Acn, either the phosphomimetic Acn(S641,731D) or the caspase-resistant Acn(D527A), exhibited enhanced basal autophagy. Physiologically, these flies showed improvements in processes known to be autophagy dependent, including increased starvation resistance, reduced Huntingtin-induced neurodegeneration, and prolonged life span. These data indicate that AKT1 and caspase-dependent regulation of Acn stability adjusts basal autophagy levels.
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Affiliation(s)
- Nilay Nandi
- Department of Neuroscience and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Lauren K Tyra
- Department of Neuroscience and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Drew Stenesen
- Department of Neuroscience and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Helmut Krämer
- Department of Neuroscience and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390 Department of Neuroscience and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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Abstract
Neurons fire by releasing neurotransmitters via fusion of synaptic vesicles with the plasma membrane. Fusion can be evoked by an incoming signal from a preceding neuron or can occur spontaneously. Synaptic vesicle fusion requires the formation of trans complexes between SNAREs as well as Ca(2+) ions. Wang et al. (2014. J. Cell Biol. http://dx.doi.org/jcb.201312109) now find that the Ca(2+)-binding protein Calmodulin promotes spontaneous release and SNARE complex formation via its interaction with the V0 sector of the V-ATPase.
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Affiliation(s)
- Stefano Vavassori
- Département de Biochimie, Université de Lausanne, 1066 Epalinges, Switzerland
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Wang D, Epstein D, Khalaf O, Srinivasan S, Williamson WR, Fayyazuddin A, Quiocho FA, Hiesinger PR. Ca2+-Calmodulin regulates SNARE assembly and spontaneous neurotransmitter release via v-ATPase subunit V0a1. ACTA ACUST UNITED AC 2014; 205:21-31. [PMID: 24733584 PMCID: PMC3987144 DOI: 10.1083/jcb.201312109] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Ca2+–Calmodulin binding to neuronal v-ATPase V0 subunit a1 (V100) regulates SNARE complex assembly for a putative subset of synaptic vesicles that sustain spontaneous release in Drosophila. Most chemical neurotransmission occurs through Ca2+-dependent evoked or spontaneous vesicle exocytosis. In both cases, Ca2+ sensing is thought to occur shortly before exocytosis. In this paper, we provide evidence that the Ca2+ dependence of spontaneous vesicle release may partly result from an earlier requirement of Ca2+ for the assembly of soluble N-ethylmaleimide–sensitive fusion attachment protein receptor (SNARE) complexes. We show that the neuronal vacuolar-type H+-adenosine triphosphatase V0 subunit a1 (V100) can regulate the formation of SNARE complexes in a Ca2+–Calmodulin (CaM)-dependent manner. Ca2+–CaM regulation of V100 is not required for vesicle acidification. Specific disruption of the Ca2+-dependent regulation of V100 by CaM led to a >90% loss of spontaneous release but only had a mild effect on evoked release at Drosophila melanogaster embryo neuromuscular junctions. Our data suggest that Ca2+–CaM regulation of V100 may control SNARE complex assembly for a subset of synaptic vesicles that sustain spontaneous release.
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Affiliation(s)
- Dong Wang
- Department of Physiology and 2 Green Center Division for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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Tuttle AM, Hoffman TL, Schilling TF. Rabconnectin-3a regulates vesicle endocytosis and canonical Wnt signaling in zebrafish neural crest migration. PLoS Biol 2014; 12:e1001852. [PMID: 24802872 PMCID: PMC4011682 DOI: 10.1371/journal.pbio.1001852] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 03/28/2014] [Indexed: 12/15/2022] Open
Abstract
Cell migration requires dynamic regulation of cell-cell signaling and cell adhesion. Both of these processes involve endocytosis, lysosomal degradation, and recycling of ligand-receptor complexes and cell adhesion molecules from the plasma membrane. Neural crest (NC) cells in vertebrates are highly migratory cells, which undergo an epithelial-mesenchymal transition (EMT) to leave the neural epithelium and migrate throughout the body to give rise to many different derivatives. Here we show that the v-ATPase interacting protein, Rabconnectin-3a (Rbc3a), controls intracellular trafficking events and Wnt signaling during NC migration. In zebrafish embryos deficient in Rbc3a, or its associated v-ATPase subunit Atp6v0a1, many NC cells fail to migrate and misregulate expression of cadherins. Surprisingly, endosomes in Rbc3a- and Atp6v0a1-deficient NC cells remain immature but still acidify. Rbc3a loss-of-function initially downregulates several canonical Wnt targets involved in EMT, but later Frizzled-7 accumulates at NC cell membranes, and nuclear B-catenin levels increase. Presumably due to this later Wnt signaling increase, Rbc3a-deficient NC cells that fail to migrate become pigment progenitors. We propose that Rbc3a and Atp6v0a1 promote endosomal maturation to coordinate Wnt signaling and intracellular trafficking of Wnt receptors and cadherins required for NC migration and cell fate determination. Our results suggest that different v-ATPases and associated proteins may play cell-type-specific functions in intracellular trafficking in many contexts.
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Affiliation(s)
- Adam M. Tuttle
- Department of Developmental and Cell Biology, University of California, Irvine, California, United States of America
| | - Trevor L. Hoffman
- Department of Developmental and Cell Biology, University of California, Irvine, California, United States of America
| | - Thomas F. Schilling
- Department of Developmental and Cell Biology, University of California, Irvine, California, United States of America
- * E-mail:
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Abstract
A decade ago, the (P)RR [(pro)renin receptor] was discovered and depicted as a potential activator of the tissue renin-angiotensin system. For this reason, the role of the (P)RR in cardiovascular diseases and diabetes has been particularly studied. However, the discovery of embryonic lethality after (P)RR gene deletion in mouse and zebrafish paved the way for additional roles of (P)RR in cell homoeostasis. Indeed, the (P)RR has been shown to associate with vacuolar H+-ATPase, hence its other name ATP6ap2. Developmental studies in Xenopus and Drosophila have revealed an essential role of this association to promote the canonical and non-canonical Wnt signalling pathways, whereas studies with tissue-specific gene deletion have pointed out a role in autophagy. The present review aims to summarize recent findings on the cellular functions of (P)RR emerging from various mutated and transgenic animal models.
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Shine L, Kilty C, Gross J, Kennedy B. Vacuolar ATPases and their role in vision. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:97-103. [PMID: 24664686 DOI: 10.1007/978-1-4614-3209-8_13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Vacuolar ATPases (v-ATPases) hydrolyze adenosine triphospate (ATP) to pump protons across cell membranes. Mutations in v-ATPase subunits are implicated in three human disorders: distal renal tubular acidosis, osteopetrosis, and cutis laxa type II. In the eye, the role of v-ATPases is only emerging. Mutations in v-ATPase subunits are not linked to human blindness, but altered proton pump function may underlie ocular pathologies. For example, inhibition of v-ATPase by A2E may accentuate age-related macular degeneration (AMD). In animal models, v-ATPase mutations perturb the retinal pigment epithelium (RPE) and photoreceptor outer segment (OS) phagocytosis, an event linked to retinal degeneration. As the RPE plays essential roles in eye development and vision, the study of v-ATPase-induced RPE dysfunction may improve our understanding of RPE diseases.
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Affiliation(s)
- Lisa Shine
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland,
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