1
|
Bolamperti S, Villa I, Rubinacci A. Bone remodeling: an operational process ensuring survival and bone mechanical competence. Bone Res 2022; 10:48. [PMID: 35851054 PMCID: PMC9293977 DOI: 10.1038/s41413-022-00219-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 05/02/2022] [Accepted: 05/15/2022] [Indexed: 12/12/2022] Open
Abstract
Bone remodeling replaces old and damaged bone with new bone through a sequence of cellular events occurring on the same surface without any change in bone shape. It was initially thought that the basic multicellular unit (BMU) responsible for bone remodeling consists of osteoclasts and osteoblasts functioning through a hierarchical sequence of events organized into distinct stages. However, recent discoveries have indicated that all bone cells participate in BMU formation by interacting both simultaneously and at different differentiation stages with their progenitors, other cells, and bone matrix constituents. Therefore, bone remodeling is currently considered a physiological outcome of continuous cellular operational processes optimized to confer a survival advantage. Bone remodeling defines the primary activities that BMUs need to perform to renew successfully bone structural units. Hence, this review summarizes the current understanding of bone remodeling and future research directions with the aim of providing a clinically relevant biological background with which to identify targets for therapeutic strategies in osteoporosis.
Collapse
Affiliation(s)
- Simona Bolamperti
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Isabella Villa
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Alessandro Rubinacci
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy.
| |
Collapse
|
2
|
Novel vertebrate- and brain-specific driver of neuronal outgrowth. Prog Neurobiol 2021; 202:102069. [PMID: 33933532 DOI: 10.1016/j.pneurobio.2021.102069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 03/31/2021] [Accepted: 04/21/2021] [Indexed: 12/30/2022]
Abstract
During the process of neuronal outgrowth, developing neurons produce new projections, neurites, that are essential for brain wiring. Here, we discover a relatively late-evolved protein that we denote Ac45-related protein (Ac45RP) and that, surprisingly, drives neuronal outgrowth. Ac45RP is a paralog of the Ac45 protein that is a component of the vacuolar proton ATPase (V-ATPase), the main pH regulator in eukaryotic cells. Ac45RP mRNA expression is brain specific and coincides with the peak of neurogenesis and the onset of synaptogenesis. Furthermore, Ac45RP physically interacts with the V-ATPase V0-sector and colocalizes with V0 in unconventional, but not synaptic, secretory vesicles of extending neurites. Excess Ac45RP enhances the expression of V0-subunits, causes a more elaborate Golgi, and increases the number of cytoplasmic vesicular structures, plasma membrane formation and outgrowth of actin-containing neurites devoid of synaptic markers. CRISPR-cas9n-mediated Ac45RP knockdown reduces neurite outgrowth. We conclude that the novel vertebrate- and brain-specific Ac45RP is a V0-interacting constituent of unconventional vesicular structures that drives membrane expansion during neurite outgrowth and as such may furnish a tool for future neuroregenerative treatment strategies.
Collapse
|
3
|
Chitirala P, Ravichandran K, Schirra C, Chang HF, Krause E, Kazmaier U, Lauterbach MA, Rettig J. Role of V-ATPase a3-Subunit in Mouse CTL Function. THE JOURNAL OF IMMUNOLOGY 2020; 204:2818-2828. [PMID: 32269094 DOI: 10.4049/jimmunol.1901536] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 02/26/2020] [Indexed: 12/17/2022]
Abstract
CTLs release cytotoxic proteins such as granzymes and perforin through fusion of cytotoxic granules (CG) at the target cell interface, the immune synapse, to kill virus-infected and tumorigenic target cells. A characteristic feature of these granules is their acidic pH inside the granule lumen, which is required to process precursors of granzymes and perforin to their mature form. However, the role of acidic pH in CG maturation, transport, and fusion is not understood. We demonstrate in primary murine CTLs that the a3-subunit of the vacuolar-type (H+)-adenosine triphosphatase is required for establishing a luminal pH of 6.1 inside CG using ClopHensorN(Q69M), a newly generated CG-specific pH indicator. Knockdown of the a3-subunit resulted in a significantly reduced killing of target cells and a >50% reduction in CG fusion in total internal reflection fluorescence microscopy, which was caused by a reduced number of CG at the immune synapse. Superresolution microscopy revealed a reduced interaction of CG with the microtubule network upon a3-subunit knockdown. Finally, we find by electron and structured illumination microscopy that knockdown of the a3-subunit altered the diameter and density of individual CG, whereas the number of CG per CTL was unaffected. We conclude that the a3-subunit of the vacuolar adenosine triphosphatase is not only responsible for the acidification of CG, but also contributes to the maturation and efficient transport of the CG to the immune synapse.
Collapse
Affiliation(s)
- Praneeth Chitirala
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Keerthana Ravichandran
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Claudia Schirra
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Hsin-Fang Chang
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Uli Kazmaier
- Organic Chemistry, Saarland University, 66123 Saarbrücken, Germany; and
| | - Marcel A Lauterbach
- Molecular Imaging, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany;
| |
Collapse
|
4
|
Lee H, Yoon DE, Kim K. Genome editing methods in animal models. Anim Cells Syst (Seoul) 2020; 24:8-16. [PMID: 32158611 PMCID: PMC7048190 DOI: 10.1080/19768354.2020.1726462] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/03/2020] [Indexed: 12/15/2022] Open
Abstract
Genetically engineered animal models that reproduce human diseases are very important for the pathological study of various conditions. The development of the clustered regularly interspaced short palindromic repeats (CRISPR) system has enabled a faster and cheaper production of animal models compared with traditional gene-targeting methods using embryonic stem cells. Genome editing tools based on the CRISPR-Cas9 system are a breakthrough technology that allows the precise introduction of mutations at the target DNA sequences. In particular, this accelerated the creation of animal models, and greatly contributed to the research that utilized them. In this review, we introduce various strategies based on the CRISPR-Cas9 system for building animal models of human diseases and describe various in vivo delivery methods of CRISPR-Cas9 that are applied to disease models for therapeutic purposes. In addition, we summarize the currently available animal models of human diseases that were generated using the CRISPR-Cas9 system and discuss future directions.
Collapse
Affiliation(s)
- Hyunji Lee
- Center for Genome Engineering, Institute for Basic Science, Daejeon, Republic of Korea
| | - Da Eun Yoon
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea.,Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
| | - Kyoungmi Kim
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea.,Department of Physiology, Korea University College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
5
|
Wu N, Liu B, Du H, Zhao S, Li Y, Cheng X, Wang S, Lin J, Zhou J, Qiu G, Wu Z, Zhang J. The Progress of CRISPR/Cas9-Mediated Gene Editing in Generating Mouse/Zebrafish Models of Human Skeletal Diseases. Comput Struct Biotechnol J 2019; 17:954-962. [PMID: 31360334 PMCID: PMC6639410 DOI: 10.1016/j.csbj.2019.06.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/28/2019] [Accepted: 06/11/2019] [Indexed: 12/18/2022] Open
Abstract
Genetic factors play a substantial role in the etiology of skeletal diseases, which involve 1) defects in skeletal development, including intramembranous ossification and endochondral ossification; 2) defects in skeletal metabolism, including late bone growth and bone remodeling; 3) defects in early developmental processes related to skeletal diseases, such as neural crest cell (NCC) and cilia functions; 4) disturbance of the cellular signaling pathways which potentially affect bone growth. Efficient and high-throughput genetic methods have enabled the exploration and verification of disease-causing genes and variants. Animal models including mouse and zebrafish have been extensively used in functional mechanism studies of causal genes and variants. The conventional approaches of generating mutant animal models include spontaneous mutagenesis, random integration, and targeted integration via mouse embryonic stem cells. These approaches are costly and time-consuming. Recent development and application of gene-editing tools, especially the CRISPR/Cas9 system, has significantly accelerated the process of gene-editing in diverse organisms. Here we review both mice and zebrafish models of human skeletal diseases generated by CRISPR/Cas9 system, and their contributions to deciphering the underpins of disease mechanisms.
Collapse
Affiliation(s)
- Nan Wu
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
- Medical Research Center of Orthopedics, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Bowen Liu
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
| | - Huakang Du
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
| | - Sen Zhao
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
| | - Yaqi Li
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
| | - Xi Cheng
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
| | - Shengru Wang
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
| | - Jiachen Lin
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
| | - Junde Zhou
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
| | | | - Guixing Qiu
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
- Medical Research Center of Orthopedics, Chinese Academy of Medical Sciences, Beijing 100730, China
- Central Laboratory & Medical Research Center, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Zhihong Wu
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
- Central Laboratory & Medical Research Center, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Jianguo Zhang
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
- Beijing Key Laboratory for Genetic Research of Skeletal Deformity, Beijing 100730, China
- Medical Research Center of Orthopedics, Chinese Academy of Medical Sciences, Beijing 100730, China
| |
Collapse
|
6
|
Duan X, Yang S, Zhang L, Yang T. V-ATPases and osteoclasts: ambiguous future of V-ATPases inhibitors in osteoporosis. Theranostics 2018; 8:5379-5399. [PMID: 30555553 PMCID: PMC6276090 DOI: 10.7150/thno.28391] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
Vacuolar ATPases (V-ATPases) play a critical role in regulating extracellular acidification of osteoclasts and bone resorption. The deficiencies of subunit a3 and d2 of V-ATPases result in increased bone density in humans and mice. One of the traditional drug design strategies in treating osteoporosis is the use of subunit a3 inhibitor. Recent findings connect subunits H and G1 with decreased bone density. Given the controversial effects of ATPase subunits on bone density, there is a critical need to review the subunits of V-ATPase in osteoclasts and their functions in regulating osteoclasts and bone remodeling. In this review, we comprehensively address the following areas: information about all V-ATPase subunits and their isoforms; summary of V-ATPase subunits associated with human genetic diseases; V-ATPase subunits and osteopetrosis/osteoporosis; screening of all V-ATPase subunits variants in GEFOS data and in-house data; spectrum of V-ATPase subunits during osteoclastogenesis; direct and indirect roles of subunits of V-ATPases in osteoclasts; V-ATPase-associated signaling pathways in osteoclasts; interactions among V-ATPase subunits in osteoclasts; osteoclast-specific V-ATPase inhibitors; perspective of future inhibitors or activators targeting V-ATPase subunits in the treatment of osteoporosis.
Collapse
Affiliation(s)
- Xiaohong Duan
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Department of Oral Biology, Clinic of Oral Rare and Genetic Diseases, School of Stomatology, the Fourth Military Medical University, 145 West Changle Road, Xi'an 710032, P. R. China
| | - Shaoqing Yang
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Department of Oral Biology, Clinic of Oral Rare and Genetic Diseases, School of Stomatology, the Fourth Military Medical University, 145 West Changle Road, Xi'an 710032, P. R. China
| | - Lei Zhang
- Center for Genetic Epidemiology and Genomics, School of Public Health, Medical College of Soochow University, 199 Renai Road, Suzhou, Jiangsu, P. R. China
| | - Tielin Yang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, 28 West Xianning Road, Xi'an 710049, People's Republic of China
| |
Collapse
|
7
|
Duan X, Liu J, Zheng X, Wang Z, Zhang Y, Hao Y, Yang T, Deng H. Deficiency of ATP6V1H Causes Bone Loss by Inhibiting Bone Resorption and Bone Formation through the TGF-β1 Pathway. Am J Cancer Res 2016; 6:2183-2195. [PMID: 27924156 PMCID: PMC5135442 DOI: 10.7150/thno.17140] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/15/2016] [Indexed: 12/02/2022] Open
Abstract
Vacuolar-type H +-ATPase (V-ATPase) is a highly conserved, ancient enzyme that couples the energy of ATP hydrolysis to proton transport across vesicular and plasma membranes of eukaryotic cells. Previously reported mutations of various V-ATPase subunits are associated with increased bone density. We now show that haploinsufficiency for the H subunit of the V1 domain (ATP6V1H) is associated with osteoporosis in humans and mice. A genome-wide SNP array analysis of 1625 Han Chinese found that 4 of 15 tag SNPs (26.7%) within ATP6V1H were significantly associated with low spine bone mineral density. Atp6v1h+/- knockout mice generated by the CRISPR/Cas9 technique had decreased bone remodeling and a net bone matrix loss. Atp6v1h+/- osteoclasts showed impaired bone formation and increased bone resorption. The increased intracellular pH of Atp6v1h+/- osteoclasts downregulated TGF-β1 activation, thereby reducing induction of osteoblast formation but the bone mineralization was not altered. However, bone formation was reduced more than bone resorption. Our data provide evidence that partial loss of ATP6V1H function results in osteoporosis/osteopenia. We propose that defective osteoclast formation triggers impaired bone formation by altering bone remodeling. In the future, ATP6V1H might, therefore, serve as a target for the therapy of osteoporosis.
Collapse
|
8
|
Makaryan V, Rosenthal EA, Bolyard AA, Kelley ML, Below JE, Bamshad MJ, Bofferding KM, Smith JD, Buckingham K, Boxer LA, Skokowa J, Welte K, Nickerson DA, Jarvik GP, Dale DC. TCIRG1-associated congenital neutropenia. Hum Mutat 2014; 35:824-7. [PMID: 24753205 DOI: 10.1002/humu.22563] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 03/28/2014] [Indexed: 11/12/2022]
Abstract
Severe congenital neutropenia (SCN) is a rare hematopoietic disorder, with estimated incidence of 1 in 200,000 individuals of European descent, many cases of which are inherited in an autosomal dominant pattern. Despite the fact that several causal genes have been identified, the genetic basis for >30% of cases remains unknown. We report a five-generation family segregating a novel single nucleotide variant (SNV) in TCIRG1. There is perfect cosegregation of the SNV with congenital neutropenia in this family; all 11 affected, but none of the unaffected, individuals carry this novel SNV. Western blot analysis show reduced levels of TCIRG1 protein in affected individuals, compared to healthy controls. Two unrelated patients with SCN, identified by independent investigators, are heterozygous for different, rare, highly conserved, coding variants in TCIRG1.
Collapse
Affiliation(s)
- Vahagn Makaryan
- Department of Medicine, Divisions of GIM, University of Washington, Seattle, Washington
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Slc26a11 is prominently expressed in the brain and functions as a chloride channel: expression in Purkinje cells and stimulation of V H⁺-ATPase. Pflugers Arch 2013; 465:1583-97. [PMID: 23733100 DOI: 10.1007/s00424-013-1300-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/13/2013] [Accepted: 05/14/2013] [Indexed: 02/07/2023]
Abstract
SLC26A11 (human)/Slc26a11 (mouse), also known as kidney brain anion transporter (KBAT), is a member of the SLC26 anion transporter family and shows abundant mRNA expression in the brain. However, its exact cellular distribution and subcellular localization in the brain and its functional identity and possible physiological roles remain unknown. Expression and immunostaining studies demonstrated that Slc26a11 is abundantly expressed in the cerebellum, with a predominant expression in Purkinje cells. Lower expression levels were detected in hippocampus, olfactory bulb, cerebral cortex, and subcortical structures. Patch clamp studies in HEK293 cells transfected with mouse cDNA demonstrated that Slc26a11 can function as a chloride channel that is active under basal conditions and is not regulated by calcium, forskolin, or co-expression with cystic fibrosis transmembrane regulator. Single and double immunofluorescent labeling studies demonstrated the localization of vacuolar (V) H⁺-ATPase and Slc26a11 (KBAT) in the plasma membrane in Purkinje cells. Functional studies in HEK293 cells indicated that transfection with Slc26a11 stimulated acid transport via endogenous V H⁺-ATPase. We conclude that Slc26a11 (KBAT) is prominently distributed in output neurons of various subcortical and cortical structures in the central nervous system, with specific expression in Purkinje cells and that it may operate as a chloride channel regulating acid translocation by H⁺-ATPase across the plasma membrane and in intracellular compartments.
Collapse
|
10
|
Proton pump (H+/K+-ATPase) inhibitors weaken the protective effect of alendronate on bone mechanical properties in estrogen-deficient rats. Pharmacol Rep 2012; 64:625-34. [DOI: 10.1016/s1734-1140(12)70858-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 03/09/2012] [Indexed: 11/17/2022]
|
11
|
Ma B, Xiang Y, An L. Structural bases of physiological functions and roles of the vacuolar H(+)-ATPase. Cell Signal 2011; 23:1244-56. [PMID: 21397012 DOI: 10.1016/j.cellsig.2011.03.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 03/03/2011] [Indexed: 12/09/2022]
Abstract
Vacuolar-type H(+)-ATPases (V-ATPases) is a large multi-protein complex containing at least 14 different subunits, in which subunits A, B, C, D, E, F, G, and H compose the peripheral 500-kDa V(1) responsible for ATP hydrolysis, and subunits a, c, c', c″, and d assembly the 250-kDa membrane-integral V(0) harboring the rotary mechanism to transport protons across the membrane. The assembly of V-ATPases requires the presence of all V(1) and V(0) subunits, in which the V(1) must be completely assembled prior to association with the V(0), accordingly the V(0) failing to assemble cannot provide a membrane anchor for the V(1), thereby prohibiting membrane association of the V-ATPase subunits. The V-ATPase mediates acidification of intracellular compartments and regulates diverse critical physiological processes of cell for functions of its numerous functional subunits. The core catalytic mechanism of the V-ATPase is a rotational catalytic mechanism. The V-ATPase holoenzyme activity is regulated by the reversible assembly/disassembly of the V(1) and V(0), the targeting and recycling of V-ATPase-containing vesicles to and from the plasma membrane, the coupling ratio between ATP hydrolysis and proton pumping, ATP, Ca(2+), and its inhibitors and activators.
Collapse
Affiliation(s)
- Binyun Ma
- Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, School of Life Sciences, Lanzhou University, 730000, Lanzhou, China
| | | | | |
Collapse
|
12
|
The vacuolar ATPase in bone cells: a potential therapeutic target in osteoporosis. Mol Biol Rep 2010; 37:3561-6. [DOI: 10.1007/s11033-010-0004-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2009] [Accepted: 02/08/2010] [Indexed: 11/26/2022]
|
13
|
Johnson RM, Allen C, Melman SD, Waller A, Young SM, Sklar LA, Parra KJ. Identification of inhibitors of vacuolar proton-translocating ATPase pumps in yeast by high-throughput screening flow cytometry. Anal Biochem 2009; 398:203-11. [PMID: 20018164 DOI: 10.1016/j.ab.2009.12.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/22/2009] [Accepted: 12/10/2009] [Indexed: 11/28/2022]
Abstract
Fluorescence intensity of the pH-sensitive carboxyfluorescein derivative 2,7-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) was monitored by high-throughput flow cytometry in living yeast cells. We measured fluorescence intensity of BCECF trapped in yeast vacuoles, acidic compartments equivalent to lysosomes where vacuolar proton-translocating ATPases (V-ATPases) are abundant. Because V-ATPases maintain a low pH in the vacuolar lumen, V-ATPase inhibition by concanamycin A alkalinized the vacuole and increased BCECF fluorescence. Likewise, V-ATPase-deficient mutant cells had greater fluorescence intensity than wild-type cells. Thus, we detected an increase of fluorescence intensity after short- and long-term inhibition of V-ATPase function. We used yeast cells loaded with BCECF to screen a small chemical library of structurally diverse compounds to identify V-ATPase inhibitors. One compound, disulfiram, enhanced BCECF fluorescence intensity (although to a degree beyond that anticipated for pH changes alone in the mutant cells). Once confirmed by dose-response assays (EC(50)=26 microM), we verified V-ATPase inhibition by disulfiram in secondary assays that measured ATP hydrolysis in vacuolar membranes. The inhibitory action of disulfiram against V-ATPase pumps revealed a novel effect previously unknown for this compound. Because V-ATPases are highly conserved, new inhibitors identified could be used as research and therapeutic tools in cancer, viral infections, and other diseases where V-ATPases are involved.
Collapse
Affiliation(s)
- Rebecca M Johnson
- Department of Biochemistry and Molecular Biology, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | | | | | | | | | | | | |
Collapse
|
14
|
Synthesis of C18–C28 ketone fragment of micromonospolide B possessing 1,3-diene and 1,3-anti-diol functionalities. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.tetasy.2009.07.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
15
|
Ediger B, Melman SD, Pappas DL, Finch M, Applen J, Parra KJ. The tether connecting cytosolic (N terminus) and membrane (C terminus) domains of yeast V-ATPase subunit a (Vph1) is required for assembly of V0 subunit d. J Biol Chem 2009; 284:19522-32. [PMID: 19473972 DOI: 10.1074/jbc.m109.013375] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
V-ATPases are molecular motors that reversibly disassemble in vivo. Anchored in the membrane is subunit a. Subunit a has a movable N terminus that switches positions during disassembly and reassembly. Deletions were made at residues securing the N terminus of subunit a (yeast isoform Vph1) to its membrane-bound C-terminal domain in order to understand the role of this conserved region for V-ATPase function. Shrinking of the tether made cells pH-sensitive (vma phenotype) because assembly of V(0) subunit d was harmed. Subunit d did not co-immunoprecipitate with subunit a and the c-ring. Cells contained pools of V(1) and V(0)(-d) that failed to form V(1)V(0), and very low levels of V-ATPase subunits were found at the membrane. Although subunit d expression was stable and at wild-type levels, growth defects were rescued by exogenous VMA6 (subunit d). Stable V(1)V(0) assembled after yeast cells were co-transformed with VMA6 and mutant VPH1. Tether-less V(1)V(0) was delivered to the vacuole and active. It retained 63-71% of the wild-type activity and was responsive to glucose. Tether-less V(1)V(0) disassembled and reassembled after brief glucose depletion and readdition. The N terminus retained binding to V(1) subunits and the C terminus to phosphofructokinase. Thus, no major structural change was generated at the N and C termini of subunit a. We concluded that early steps of V(0) assembly and trafficking were likely impaired by shorter tethers and rescued by VMA6.
Collapse
Affiliation(s)
- Benjamin Ediger
- Department of Biochemistry and Molecular Biology, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA
| | | | | | | | | | | |
Collapse
|
16
|
Bratanic A, Kokic S, Hozo I, Barisic I, Kokic V. Long-term therapy with proton pump inhibitors is associated with decreased bone density. Med Hypotheses 2009; 72:608-9. [DOI: 10.1016/j.mehy.2009.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 12/18/2008] [Accepted: 01/12/2009] [Indexed: 11/26/2022]
|
17
|
Saroussi S, Nelson N. Vacuolar H+-ATPase—an enzyme for all seasons. Pflugers Arch 2008; 457:581-7. [PMID: 18320212 DOI: 10.1007/s00424-008-0458-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 01/14/2008] [Indexed: 01/02/2023]
|
18
|
The V-ATPase in Paramecium: functional specialization by multiple gene isoforms. Pflugers Arch 2008; 457:599-607. [DOI: 10.1007/s00424-007-0417-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2007] [Revised: 11/23/2007] [Accepted: 11/29/2007] [Indexed: 11/25/2022]
|
19
|
Xiao YT, Xiang LX, Shao JZ. Vacuolar H+-ATPase. Int J Biochem Cell Biol 2008; 40:2002-6. [PMID: 17897871 DOI: 10.1016/j.biocel.2007.08.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 08/09/2007] [Accepted: 08/09/2007] [Indexed: 12/09/2022]
Abstract
The vacuolar H(+)-ATPase (V-ATPase) is a universal component of eukaryotic organisms, which is present in both intracellular compartments and the plasma membrane. In the latter, its proton-pumping action creates the low intravacuolar pH, benefiting many processes such as, membrane trafficking, protein degradation, renal acidification, bone resorption, and tumor metastasis. In this article, we briefly summarize recent studies on the essential and diverse roles of mammalian V-ATPase and their medical applications, with a special emphasis on identification and use of V-ATPase inhibitors.
Collapse
Affiliation(s)
- Yong-Tao Xiao
- Institute of Cell Biology and Genetics, College of Life Sciences, Zhejiang University, Postal code: 310058, China.
| | | | | |
Collapse
|