601
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Chen L, Wang K, Long A, Jia L, Zhang Y, Deng H, Li Y, Han J, Wang Y. Fasting-induced hormonal regulation of lysosomal function. Cell Res 2017; 27:748-763. [PMID: 28374748 PMCID: PMC5518872 DOI: 10.1038/cr.2017.45] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 02/19/2017] [Accepted: 02/24/2017] [Indexed: 12/14/2022] Open
Abstract
Lysosomes are centers for nutrient sensing and recycling that allow mammals to adapt to starvation. Regulation of lysosome dynamics by internal nutrient signaling is well described, but the mechanisms by which external cues modulate lysosomal function are unclear. Here, we describe an essential role of the fasting-induced hormone fibroblast growth factor 21 (FGF21) in lysosome homeostasis in mice. Fgf21 deficiency impairs hepatic lysosomal function by blocking transcription factor EB (TFEB), a master regulator of lysosome biogenesis and autophagy. FGF21 induces mobilization of calcium from the endoplasmic reticulum, which activates the transcriptional repressor downstream regulatory element antagonist modulator (DREAM), and thereby inhibits expression of Mid1 (encoding the E3 ligase Midline-1). Protein phosphatase PP2A, a substrate of MID1, accumulates and dephosphorylates TFEB, thereby upregulating genes involved in lysosome biogenesis, autophagy and lipid metabolism. Thus, an FGF21-TFEB signaling axis links lysosome homeostasis with extracellular hormonal signaling to orchestrate lipid metabolism during fasting.
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Affiliation(s)
- Liqun Chen
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ke Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Aijun Long
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Liangjie Jia
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yuanyuan Zhang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yu Li
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Jinbo Han
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yiguo Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
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602
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Wong CO, Gregory S, Hu H, Chao Y, Sepúlveda VE, He Y, Li-Kroeger D, Goldman WE, Bellen HJ, Venkatachalam K. Lysosomal Degradation Is Required for Sustained Phagocytosis of Bacteria by Macrophages. Cell Host Microbe 2017; 21:719-730.e6. [PMID: 28579255 DOI: 10.1016/j.chom.2017.05.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 04/06/2017] [Accepted: 05/08/2017] [Indexed: 01/28/2023]
Abstract
Clearance of bacteria by macrophages involves internalization of the microorganisms into phagosomes, which are then delivered to endolysosomes for enzymatic degradation. These spatiotemporally segregated processes are not known to be functionally coupled. Here, we show that lysosomal degradation of bacteria sustains phagocytic uptake. In Drosophila and mammalian macrophages, lysosomal dysfunction due to loss of the endolysosomal Cl- transporter ClC-b/CLCN7 delayed degradation of internalized bacteria. Unexpectedly, defective lysosomal degradation of bacteria also attenuated further phagocytosis, resulting in elevated bacterial load. Exogenous application of bacterial peptidoglycans restored phagocytic uptake in the lysosomal degradation-defective mutants via a pathway requiring cytosolic pattern recognition receptors and NF-κB. Mammalian macrophages that are unable to degrade internalized bacteria also exhibit compromised NF-κB activation. Our findings reveal a role for phagolysosomal degradation in activating an evolutionarily conserved signaling cascade, which ensures that continuous uptake of bacteria is preceded by lysosomal degradation of microbes.
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Affiliation(s)
- Ching-On Wong
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA.
| | - Steven Gregory
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA; Graduate Program in Cell and Regulatory Biology, University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Hongxiang Hu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA
| | - Yufang Chao
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA
| | - Victoria E Sepúlveda
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Yuchun He
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - David Li-Kroeger
- Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - William E Goldman
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Hugo J Bellen
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA; Graduate Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Graduate Program in Cell and Regulatory Biology, University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA; Graduate Program in Neuroscience, University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA.
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603
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Amino acid homeostasis and signalling in mammalian cells and organisms. Biochem J 2017; 474:1935-1963. [PMID: 28546457 PMCID: PMC5444488 DOI: 10.1042/bcj20160822] [Citation(s) in RCA: 306] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 12/19/2022]
Abstract
Cells have a constant turnover of proteins that recycle most amino acids over time. Net loss is mainly due to amino acid oxidation. Homeostasis is achieved through exchange of essential amino acids with non-essential amino acids and the transfer of amino groups from oxidised amino acids to amino acid biosynthesis. This homeostatic condition is maintained through an active mTORC1 complex. Under amino acid depletion, mTORC1 is inactivated. This increases the breakdown of cellular proteins through autophagy and reduces protein biosynthesis. The general control non-derepressable 2/ATF4 pathway may be activated in addition, resulting in transcription of genes involved in amino acid transport and biosynthesis of non-essential amino acids. Metabolism is autoregulated to minimise oxidation of amino acids. Systemic amino acid levels are also tightly regulated. Food intake briefly increases plasma amino acid levels, which stimulates insulin release and mTOR-dependent protein synthesis in muscle. Excess amino acids are oxidised, resulting in increased urea production. Short-term fasting does not result in depletion of plasma amino acids due to reduced protein synthesis and the onset of autophagy. Owing to the fact that half of all amino acids are essential, reduction in protein synthesis and amino acid oxidation are the only two measures to reduce amino acid demand. Long-term malnutrition causes depletion of plasma amino acids. The CNS appears to generate a protein-specific response upon amino acid depletion, resulting in avoidance of an inadequate diet. High protein levels, in contrast, contribute together with other nutrients to a reduction in food intake.
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604
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Autophagy Regulates Proteasome Inhibitor-Induced Pigmentation in Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells. Int J Mol Sci 2017; 18:ijms18051089. [PMID: 28534814 PMCID: PMC5454998 DOI: 10.3390/ijms18051089] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 02/06/2023] Open
Abstract
The impairment of autophagic and proteasomal cleansing together with changes in pigmentation has been documented in retinal pigment epithelial (RPE) cell degeneration. However, the function and co-operation of these mechanisms in melanosome-containing RPE cells is still unclear. We show that inhibition of proteasomal degradation with MG-132 or autophagy with bafilomycin A1 increased the accumulation of premelanosomes and autophagic structures in human embryonic stem cell (hESC)-derived RPE cells. Consequently, upregulation of the autophagy marker p62 (also known as sequestosome-1, SQSTM1) was confirmed in Western blot and perinuclear staining. Interestingly, cells treated with the adenosine monophosphatedependent protein kinase activator, AICAR (5-Aminoimidazole-4-carboxamide ribonucleotide), decreased the proteasome inhibitor-induced accumulation of premelanosomes, increased the amount of autophagosomes and eradicated the protein expression of p62 and LC3 (microtubule-associated protein 1A/1B-light chain 3). These results revealed that autophagic machinery is functional in hESC-RPE cells and may regulate cellular pigmentation with proteasomes.
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605
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Thomason PA, King JS, Insall RH. Mroh1, a lysosomal regulator localized by WASH-generated actin. J Cell Sci 2017; 130:1785-1795. [PMID: 28424231 PMCID: PMC5450189 DOI: 10.1242/jcs.197210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 03/29/2017] [Indexed: 02/06/2023] Open
Abstract
The steps leading to constitutive exocytosis are poorly understood. In Dictyostelium WASH complex mutants, exocytosis is blocked, so cells that take up fluorescent dextran from the medium retain it and remain fluorescent. Here, we establish a FACS-based method to select cells that retain fluorescent dextran, allowing identification of mutants with disrupted exocytosis. Screening a pool of random mutants identified members of the WASH complex, as expected, and multiple mutants in the conserved HEAT-repeat-containing protein Mroh1. In mroh1 mutants, endosomes develop normally until the stage where lysosomes neutralize to postlysosomes, but thereafter the WASH complex is recycled inefficiently, and subsequent exocytosis is substantially delayed. Mroh1 protein localizes to lysosomes in mammalian and Dictyostelium cells. In Dictyostelium, it accumulates on lysosomes as they mature and is removed, together with the WASH complex, shortly before the postlysosomes are exocytosed. WASH-generated F-actin is required for correct subcellular localization; in WASH complex mutants, and immediately after latrunculin treatment, Mroh1 relocalizes from the cytoplasm to small vesicles. Thus, Mroh1 is involved in a late and hitherto undefined actin-dependent step in exocytosis.
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Affiliation(s)
- Peter A Thomason
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Jason S King
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Robert H Insall
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
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606
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Zhao GN, Zhang P, Gong J, Zhang XJ, Wang PX, Yin M, Jiang Z, Shen LJ, Ji YX, Tong J, Wang Y, Wei QF, Wang Y, Zhu XY, Zhang X, Fang J, Xie Q, She ZG, Wang Z, Huang Z, Li H. Tmbim1 is a multivesicular body regulator that protects against non-alcoholic fatty liver disease in mice and monkeys by targeting the lysosomal degradation of Tlr4. Nat Med 2017; 23:742-752. [PMID: 28481357 DOI: 10.1038/nm.4334] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 04/07/2017] [Indexed: 02/08/2023]
Abstract
Non-alcoholic steatohepatitis (NASH) is an increasingly prevalent liver pathology that can progress from non-alcoholic fatty liver disease (NAFLD), and it is a leading cause of cirrhosis and hepatocellular carcinoma. There is currently no pharmacological therapy for NASH. Defective lysosome-mediated protein degradation is a key process that underlies steatohepatitis and a well-recognized drug target in a variety of diseases; however, whether it can serve as a therapeutic target for NAFLD and NASH remains unknown. Here we report that transmembrane BAX inhibitor motif-containing 1 (TMBIM1) is an effective suppressor of steatohepatitis and a previously unknown regulator of the multivesicular body (MVB)-lysosomal pathway. Tmbim1 expression in hepatocytes substantially inhibited high-fat diet-induced insulin resistance, hepatic steatosis and inflammation in mice. Mechanistically, Tmbim1 promoted the lysosomal degradation of toll-like receptor 4 by cooperating with the ESCRT endosomal sorting complex to facilitate MVB formation, and the ubiquitination of Tmbim1 by the E3 ubiquitin ligase Nedd4l was required for this process. We also found that overexpression of Tmbim1 in the liver effectively inhibited a severe form of NAFLD in mice and NASH progression in monkeys. Taken together, these findings could lead to the development of promising strategies to treat NASH by targeting MVB regulators to properly orchestrate the lysosome-mediated protein degradation of key mediators of the disease.
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Affiliation(s)
- Guang-Nian Zhao
- Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China.,Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,College of Life Sciences, Wuhan University, Wuhan, China
| | - Peng Zhang
- Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China.,Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China
| | - Jun Gong
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiao-Jing Zhang
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Pi-Xiao Wang
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Miao Yin
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China
| | - Zhou Jiang
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,College of Life Sciences, Wuhan University, Wuhan, China
| | - Li-Jun Shen
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yan-Xiao Ji
- Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China.,Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China
| | - Jingjing Tong
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,College of Life Sciences, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yutao Wang
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qiao-Fang Wei
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yong Wang
- Institute of Model Animal of Wuhan University, Wuhan, China
| | - Xue-Yong Zhu
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China
| | - Xin Zhang
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,College of Life Sciences, Wuhan University, Wuhan, China
| | - Jing Fang
- Division of Cardiothoracic and Vascular Surgery, Heart-Lung Transplantation Center, Sino-Swiss Heart-Lung Transplantation Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qingguo Xie
- Biomedical Engineering Department, Huazhong University of Science and Technology, Wuhan, China
| | - Zhi-Gang She
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhihua Wang
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zan Huang
- Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,College of Life Sciences, Wuhan University, Wuhan, China
| | - Hongliang Li
- Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China.,Basic Medical School, Wuhan University, Wuhan, China.,Institute of Model Animal of Wuhan University, Wuhan, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
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607
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Wang W, Zhang X, Gao Q, Lawas M, Yu L, Cheng X, Gu M, Sahoo N, Li X, Li P, Ireland S, Meredith A, Xu H. A voltage-dependent K + channel in the lysosome is required for refilling lysosomal Ca 2+ stores. J Cell Biol 2017; 216:1715-1730. [PMID: 28468834 PMCID: PMC5461029 DOI: 10.1083/jcb.201612123] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/05/2017] [Accepted: 04/10/2017] [Indexed: 01/04/2023] Open
Abstract
Ion-dependent channels and transporters have been identified in lysosomes, including the V-ATPase H+ pump and transient receptor potential mucolipin channels (TRPMLs), the principle Ca2+ release channels in the lysosome, but much less is understood about the roles of Na+ and K+ in lysosomal physiology. Wang et al. describe a voltage-sensitive, Ca2+-activated K+ current in the lysosome (LysoKVCa) and show that LysoKVCa regulates lysosomal membrane potential and refilling of lysosomal Ca2+ stores. The resting membrane potential (Δψ) of the cell is negative on the cytosolic side and determined primarily by the plasma membrane’s selective permeability to K+. We show that lysosomal Δψ is set by lysosomal membrane permeabilities to Na+ and H+, but not K+, and is positive on the cytosolic side. An increase in juxta-lysosomal Ca2+ rapidly reversed lysosomal Δψ by activating a large voltage-dependent and K+-selective conductance (LysoKVCa). LysoKVCa is encoded molecularly by SLO1 proteins known for forming plasma membrane BK channels. Opening of single LysoKVCa channels is sufficient to cause the rapid, striking changes in lysosomal Δψ. Lysosomal Ca2+ stores may be refilled from endoplasmic reticulum (ER) Ca2+ via ER–lysosome membrane contact sites. We propose that LysoKVCa serves as the perilysosomal Ca2+ effector to prime lysosomes for the refilling process. Consistently, genetic ablation or pharmacological inhibition of LysoKVCa, or abolition of its Ca2+ sensitivity, blocks refilling and maintenance of lysosomal Ca2+ stores, resulting in lysosomal cholesterol accumulation and a lysosome storage phenotype.
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Affiliation(s)
- Wuyang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Xiaoli Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Qiong Gao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Maria Lawas
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Lu Yu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Xiping Cheng
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Mingxue Gu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Nirakar Sahoo
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Xinran Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Ping Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109.,Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China
| | - Stephen Ireland
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Andrea Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
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608
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Block RC, Razani B. Linking lysosomal acid lipase insufficiency to the development of cryptogenic cirrhosis. Atherosclerosis 2017; 262:140-142. [PMID: 28502381 DOI: 10.1016/j.atherosclerosis.2017.04.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 01/21/2023]
Affiliation(s)
- Robert C Block
- Department of Public Health Sciences, Cardiology Division, University of Rochester School of Medicine and Dentistry, Rochester, NY 14618, USA; Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14618, USA.
| | - Babak Razani
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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609
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Abstract
The mechanistic target of rapamycin (mTOR) signaling pathway regulates many metabolic and physiological processes in different organs or tissues. Dysregulation of mTOR signaling has been implicated in many human diseases including obesity, diabetes, cancer, fatty liver diseases, and neuronal disorders. Here we review recent progress in understanding how mTORC1 (mTOR complex 1) signaling regulates lipid metabolism in the liver.
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610
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Kelu JJ, Webb SE, Parrington J, Galione A, Miller AL. Ca 2+ release via two-pore channel type 2 (TPC2) is required for slow muscle cell myofibrillogenesis and myotomal patterning in intact zebrafish embryos. Dev Biol 2017; 425:109-129. [PMID: 28390800 DOI: 10.1016/j.ydbio.2017.03.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/30/2017] [Accepted: 03/31/2017] [Indexed: 01/14/2023]
Abstract
We recently demonstrated a critical role for two-pore channel type 2 (TPC2)-mediated Ca2+ release during the differentiation of slow (skeletal) muscle cells (SMC) in intact zebrafish embryos, via the introduction of a translational-blocking morpholino antisense oligonucleotide (MO). Here, we extend our study and demonstrate that knockdown of TPC2 with a non-overlapping splice-blocking MO, knockout of TPC2 (via the generation of a tpcn2dhkz1a mutant line of zebrafish using CRISPR/Cas9 gene-editing), or the pharmacological inhibition of TPC2 action with bafilomycin A1 or trans-ned-19, also lead to a significant attenuation of SMC differentiation, characterized by a disruption of SMC myofibrillogenesis and gross morphological changes in the trunk musculature. When the morphants were injected with tpcn2-mRNA or were treated with IP3/BM or caffeine (agonists of the inositol 1,4,5-trisphosphate receptor (IP3R) and ryanodine receptor (RyR), respectively), many aspects of myofibrillogenesis and myotomal patterning (and in the case of the pharmacological treatments, the Ca2+ signals generated in the SMCs), were rescued. STED super-resolution microscopy revealed a close physical relationship between clusters of RyR in the terminal cisternae of the sarcoplasmic reticulum (SR), and TPC2 in lysosomes, with a mean estimated separation of ~52-87nm. Our data therefore add to the increasing body of evidence, which indicate that localized Ca2+ release via TPC2 might trigger the generation of more global Ca2+ release from the SR via Ca2+-induced Ca2+ release.
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MESH Headings
- Animals
- Base Sequence
- Behavior, Animal/drug effects
- Body Patterning/drug effects
- CRISPR-Cas Systems/genetics
- Caffeine/pharmacology
- Calcium/metabolism
- Calcium Channels/metabolism
- Calcium Signaling/drug effects
- Cell Death/drug effects
- Cells, Cultured
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/metabolism
- Gene Knockdown Techniques
- Gene Knockout Techniques
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Kinesins/metabolism
- Macrolides/pharmacology
- Models, Biological
- Morpholinos/pharmacology
- Motor Activity/drug effects
- Muscle Cells/cytology
- Muscle Cells/drug effects
- Muscle Cells/metabolism
- Muscle Development/drug effects
- Muscle Fibers, Slow-Twitch/cytology
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Phenotype
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Ryanodine Receptor Calcium Release Channel/metabolism
- Sarcomeres/drug effects
- Sarcomeres/metabolism
- Zebrafish/embryology
- Zebrafish/metabolism
- Zebrafish Proteins/metabolism
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Affiliation(s)
- Jeffrey J Kelu
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PR China
| | - Sarah E Webb
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PR China
| | - John Parrington
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK
| | - Andrew L Miller
- Division of Life Science & State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PR China; Marine Biological Laboratory, Woods Hole, MA, USA.
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611
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Recombinant tandem of pore-domains in a Weakly Inward rectifying K + channel 2 (TWIK2) forms active lysosomal channels. Sci Rep 2017; 7:649. [PMID: 28381826 PMCID: PMC5428834 DOI: 10.1038/s41598-017-00640-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 03/07/2017] [Indexed: 12/27/2022] Open
Abstract
Recombinant TWIK2 channels produce weak basal background K+ currents. Current amplitudes depend on the animal species the channels have been isolated from and on the heterologous system used for their re-expression. Here we show that this variability is due to a unique cellular trafficking. We identified three different sequence signals responsible for the preferential expression of TWIK2 in the Lamp1-positive lysosomal compartment. Sequential inactivation of tyrosine-based (Y308ASIP) and di-leucine-like (E266LILL and D282EDDQVDIL) trafficking motifs progressively abolishes the targeting of TWIK2 to lysosomes, and promotes its functional relocation at the plasma membrane. In addition, TWIK2 contains two N-glycosylation sites (N79AS and N85AS) on its luminal side, and glycosylation is necessary for expression in lysosomes. As shown by electrophysiology and electron microscopy, TWIK2 produces functional background K+ currents in the endolysosomes, and its expression affects the number and mean size of the lysosomes. These results show that TWIK2 is expressed in lysosomes, further expanding the registry of ion channels expressed in these organelles.
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612
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Stapleton M, Kubaski F, Mason RW, Yabe H, Suzuki Y, Orii KE, Orii T, Tomatsu S. Presentation and Treatments for Mucopolysaccharidosis Type II (MPS II; Hunter Syndrome). Expert Opin Orphan Drugs 2017; 5:295-307. [PMID: 29158997 PMCID: PMC5693349 DOI: 10.1080/21678707.2017.1296761] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/15/2017] [Indexed: 01/15/2023]
Abstract
INTRODUCTION Mucopolysaccharidosis Type II (MPS II; Hunter syndrome) is an X- linked lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase (IDS). IDS deficiency leads to primary accumulation of dermatan sulfate (DS) and heparan sulfate (HS). MPS II is both multi-systemic and progressive. Phenotypes are classified as either attenuated or severe (based on absence or presence of central nervous system impairment, respectively). AREAS COVERED Current treatments available are intravenous enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT), anti-inflammatory treatment, and palliative care with symptomatic surgeries. Clinical trials are being conducted for intrathecal ERT and gene therapy is under pre-clinical investigation. Treatment approaches differ based on age, clinical severity, prognosis, availability and feasibility of therapy, and health insurance.This review provides a historical account of MPS II treatment as well as treatment development with insights into benefits and/or limitations of each specific treatment. EXPERT OPINION Conventional ERT and HSCT coupled with surgical intervention and palliative therapy are currently the treatment options available to MPS II patients. Intrathecal ERT and gene therapy are currently under investigation as future therapies. These investigative treatments are critical to address the limitations in treatment of the central nervous system (CNS).
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Affiliation(s)
- Molly Stapleton
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Francyne Kubaski
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Robert W. Mason
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Hiromasa Yabe
- Department of Cell Transplantation and Regenerative Medicine, Tokai University School of Medicine, Isehara, Japan
| | - Yasuyuki Suzuki
- Medical Education Development Center, Gifu University, Gifu, Japan
| | - Kenji E. Orii
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Tadao Orii
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Shunji Tomatsu
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
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613
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Kavčič N, Pegan K, Turk B. Lysosomes in programmed cell death pathways: from initiators to amplifiers. Biol Chem 2017; 398:289-301. [DOI: 10.1515/hsz-2016-0252] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 09/05/2016] [Indexed: 01/19/2023]
Abstract
Abstract
Lysosome is the central organelle for intracellular degradation of biological macromolecules and organelles. The material destined for degradation enters the lysosomes primarily via endocytosis, autophagy and phagocytosis, and is degraded through the concerted action of more than 50 lysosomal hydrolases. However, lysosomes are also linked with numerous other processes, including cell death, inflammasome activation and immune response, as well as with lysosomal secretion and cholesterol recycling. Among them programmed cell death pathways including apoptosis have received major attention. In most of these pathways, cell death was accompanied by lysosomal membrane permeabilization and release of lysosomal constituents with an involvement of lysosomal hydrolases, including the cathepsins. However, it is less clear, whether lysosomal membrane permeabilization is really critical for the initiation of cell death programme(s). Therefore, the role of lysosomal membrane permeabilization in various programmed cell death pathways is reviewed, as well as the mechanisms leading to it.
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614
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TMEM175 deficiency impairs lysosomal and mitochondrial function and increases α-synuclein aggregation. Proc Natl Acad Sci U S A 2017; 114:2389-2394. [PMID: 28193887 DOI: 10.1073/pnas.1616332114] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Parkinson disease (PD) is a neurodegenerative disorder pathologically characterized by nigrostriatal dopamine neuron loss and the postmortem presence of Lewy bodies, depositions of insoluble α-synuclein, and other proteins that likely contribute to cellular toxicity and death during the disease. Genetic and biochemical studies have implicated impaired lysosomal and mitochondrial function in the pathogenesis of PD. Transmembrane protein 175 (TMEM175), the lysosomal K+ channel, is centered under a major genome-wide association studies peak for PD, making it a potential candidate risk factor for the disease. To address the possibility that variation in TMEM175 could play a role in PD pathogenesis, TMEM175 function was investigated in a neuronal model system. Studies confirmed that TMEM175 deficiency results in unstable lysosomal pH, which led to decreased lysosomal catalytic activity, decreased glucocerebrosidase activity, impaired autophagosome clearance by the lysosome, and decreased mitochondrial respiration. Moreover, TMEM175 deficiency in rat primary neurons resulted in increased susceptibility to exogenous α-synuclein fibrils. Following α-synuclein fibril treatment, neurons deficient in TMEM175 were found to have increased phosphorylated and detergent-insoluble α-synuclein deposits. Taken together, data from these studies suggest that TMEM175 plays a direct and critical role in lysosomal and mitochondrial function and PD pathogenesis and highlight this ion channel as a potential therapeutic target for treating PD.
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615
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Pascua-Maestro R, Diez-Hermano S, Lillo C, Ganfornina MD, Sanchez D. Protecting cells by protecting their vulnerable lysosomes: Identification of a new mechanism for preserving lysosomal functional integrity upon oxidative stress. PLoS Genet 2017; 13:e1006603. [PMID: 28182653 PMCID: PMC5325589 DOI: 10.1371/journal.pgen.1006603] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/24/2017] [Accepted: 01/24/2017] [Indexed: 12/31/2022] Open
Abstract
Environmental insults such as oxidative stress can damage cell membranes. Lysosomes are particularly sensitive to membrane permeabilization since their function depends on intraluminal acidic pH and requires stable membrane-dependent proton gradients. Among the catalog of oxidative stress-responsive genes is the Lipocalin Apolipoprotein D (ApoD), an extracellular lipid binding protein endowed with antioxidant capacity. Within the nervous system, cell types in the defense frontline, such as astrocytes, secrete ApoD to help neurons cope with the challenge. The protecting role of ApoD is known from cellular to organism level, and many of its downstream effects, including optimization of autophagy upon neurodegeneration, have been described. However, we still cannot assign a cellular mechanism to ApoD gene that explains how this protection is accomplished. Here we perform a comprehensive analysis of ApoD intracellular traffic and demonstrate its role in lysosomal pH homeostasis upon paraquat-induced oxidative stress. By combining single-lysosome in vivo pH measurements with immunodetection, we demonstrate that ApoD is endocytosed and targeted to a subset of vulnerable lysosomes in a stress-dependent manner. ApoD is functionally stable in this acidic environment, and its presence is sufficient and necessary for lysosomes to recover from oxidation-induced alkalinization, both in astrocytes and neurons. This function is accomplished by preventing lysosomal membrane permeabilization. Two lysosomal-dependent biological processes, myelin phagocytosis by astrocytes and optimization of neurodegeneration-triggered autophagy in a Drosophila in vivo model, require ApoD-related Lipocalins. Our results uncover a previously unknown biological function of ApoD, member of the finely regulated and evolutionary conserved gene family of extracellular Lipocalins. They set a lipoprotein-mediated regulation of lysosomal membrane integrity as a new mechanism at the hub of many cellular functions, critical for the outcome of a wide variety of neurodegenerative diseases. These results open therapeutic opportunities by providing a route of entry and a repair mechanism for lysosomes in pathological situations. This work is the result of our search for the mechanism of action of Apolipoprotein D (ApoD), a neuroprotective lipid-binding protein that confers cell resistance to oxidative stress. ApoD is one of the few genes consistently over-expressed in the aging brain of all vertebrate species, and no nervous system disease has been found concurring without ApoD over-expression. All evidence supports ApoD as an endogenous mechanism of protection. We demonstrate here that this extracellular lipid binding protein is endocytosed and targeted in a finely controlled way to subsets of lysosomes in need of protection, those most sensitive to oxidative stress. ApoD reveals the existence of biologically relevant lysosomal heterogeneity that conditions the oxidation state of cells, their phagocytic or autophagic capacity, and the final output in neurodegenerative conditions. The stable presence of ApoD in lysosomes is sufficient and necessary for lysosomes to recover from oxidation-induced membrane permeabilization and loss of proton gradients. ApoD-mediated control of lysosomal membrane integrity represents a new cell-protection mechanism at the hub of many cellular functions, and is critical for the outcome of a wide variety of neurodegenerative diseases. Therapeutic opportunities open, by providing a route of entry and a repair mechanism for lysosomes in pathological situations.
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Affiliation(s)
- Raquel Pascua-Maestro
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Sergio Diez-Hermano
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Concepción Lillo
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
| | - Maria D. Ganfornina
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
- * E-mail: (MDG); (DS)
| | - Diego Sanchez
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
- * E-mail: (MDG); (DS)
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616
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Erkhembaatar M, Gu DR, Lee SH, Yang YM, Park S, Muallem S, Shin DM, Kim MS. Lysosomal Ca 2+ Signaling is Essential for Osteoclastogenesis and Bone Remodeling. J Bone Miner Res 2017; 32:385-396. [PMID: 27589205 PMCID: PMC9850942 DOI: 10.1002/jbmr.2986] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/29/2016] [Accepted: 08/31/2016] [Indexed: 01/21/2023]
Abstract
Lysosomal Ca2+ emerges as a critical component of receptor-evoked Ca2+ signaling and plays a crucial role in many lysosomal and physiological functions. Lysosomal Ca2+ release is mediated by the transient receptor potential (TRP) family member TRPML1, mutations that cause the lysosomal storage disease mucolipidosis type 4. Lysosomes play a key role in osteoclast function. However, nothing is known about the role of lysosomal Ca2+ signaling in osteoclastogenesis and bone metabolism. In this study, we addressed this knowledge gap by studying the role of lysosomal Ca2+ signaling in osteoclastogenesis, osteoclast and osteoblast functions, and bone homeostasis in vivo. We manipulated lysosomal Ca2+ signaling by acute knockdown of TRPML1, deletion of TRPML1 in mice, pharmacological inhibition of lysosomal Ca2+ influx, and depletion of lysosomal Ca2+ storage using the TRPML agonist ML-SA1. We found that knockdown and deletion of TRPML1, although it did not have an apparent effect on osteoblast differentiation and bone formation, markedly attenuated osteoclast function, RANKL-induced cytosolic Ca2+ oscillations, inhibited activation of NFATc1 and osteoclastogenesis-controlling genes, suppressed the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs), and markedly reduced the differentiation of bone marrow-derived macrophages into osteoclasts. Moreover, deletion of TRPML1 resulted in enlarged lysosomes, inhibition of lysosomal secretion, and attenuated the resorptive activity of mature osteoclasts. Notably, depletion of lysosomal Ca2+ with ML-SA1 similarly abrogated RANKL-induced Ca2+ oscillations and MNC formation. Deletion of TRPML1 in mice reduced the TRAP-positive bone surfaces and impaired bone remodeling, resulting in prominent osteopetrosis. These findings demonstrate the essential role of lysosomal Ca2+ signaling in osteoclast differentiation and mature osteoclast function, which play key roles in bone homeostasis. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Munkhsoyol Erkhembaatar
- Department of Oral Physiology, and Institute of Biomaterial-Implant, College of Dentistry, Wonkwang University, Iksan, Republic of Korea.,Department of Physiology, School of Pharmacy and Bio-Medicine, Mongolian National University of Medical Science, Ulaanbaatar, Mongolia
| | - Dong Ryun Gu
- Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Republic of Korea.,Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Republic of Korea
| | - Seoung Hoon Lee
- Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Republic of Korea.,Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Republic of Korea
| | - Yu-Mi Yang
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Soonhong Park
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Dong Min Shin
- Department of Oral Biology, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Min Seuk Kim
- Department of Oral Physiology, and Institute of Biomaterial-Implant, College of Dentistry, Wonkwang University, Iksan, Republic of Korea
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617
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Structural basis of dual Ca 2+/pH regulation of the endolysosomal TRPML1 channel. Nat Struct Mol Biol 2017; 24:205-213. [PMID: 28112729 PMCID: PMC5336481 DOI: 10.1038/nsmb.3362] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/12/2016] [Indexed: 12/01/2022]
Abstract
Organellar ion channels are essential for cell physiology. Their activities are often regulated by Ca2+ and H+, which are concentrated in many organelles. Here we report a novel structural element critical for Ca2+/pH dual regulation of TRPML1, a Ca2+ release channel crucial for endolysosomal functions. TRPML1 mutations cause mucolipidosis type IV (MLIV), a severe lysosomal storage disorder characterized by neurodegeneration, mental retardation and blindness. We obtained high-resolution crystal structures of a 213-amino acid luminal domain of human TRPML1 that harbors three missense MLIV-causing mutations. This domain forms a tetramer with a highly electronegative central pore formed by a novel luminal pore-loop. Cysteine crosslinking and cryo-EM confirm this structure in the full-length channel. Structure-function studies demonstrate that Ca2+ and H+ interact with the luminal pore to exert physiologically important regulation. The MLIV-causing mutations disrupt the luminal domain structure and cause TRPML1 mislocalization. Our study provides a structural underpinning for TRPML1's regulation, assembly and pathogenesis.
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618
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Abstract
Organellar two-pore channels (TPCs) contain two copies of a Shaker-like six-transmembrane (6-TM) domain in each subunit and are ubiquitously expressed in plants and animals. Interestingly, plant and animal TPCs share high sequence similarity in the filter region, yet exhibit drastically different ion selectivity. Plant TPC1 functions as a nonselective cation channel on the vacuole membrane, whereas mammalian TPC channels have been shown to be endo/lysosomal Na+-selective or Ca2+-release channels. In this study, we performed systematic characterization of the ion selectivity of TPC1 from Arabidopsis thaliana (AtTPC1) and compared its selectivity with the selectivity of human TPC2 (HsTPC2). We demonstrate that AtTPC1 is selective for Ca2+ over Na+, but nonselective among monovalent cations (Li+, Na+, and K+). Our results also confirm that HsTPC2 is a Na+-selective channel activated by phosphatidylinositol 3,5-bisphosphate. Guided by our recent structure of AtTPC1, we converted AtTPC1 to a Na+-selective channel by mimicking the selectivity filter of HsTPC2 and identified key residues in the TPC filters that differentiate the selectivity between AtTPC1 and HsTPC2. Furthermore, the structure of the Na+-selective AtTPC1 mutant elucidates the structural basis for Na+ selectivity in mammalian TPCs.
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619
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Sbano L, Bonora M, Marchi S, Baldassari F, Medina DL, Ballabio A, Giorgi C, Pinton P. TFEB-mediated increase in peripheral lysosomes regulates store-operated calcium entry. Sci Rep 2017; 7:40797. [PMID: 28084445 PMCID: PMC5233950 DOI: 10.1038/srep40797] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/09/2016] [Indexed: 01/04/2023] Open
Abstract
Lysosomes are membrane-bound organelles mainly involved in catabolic processes. In addition, lysosomes can expel their contents outside of the cell via lysosomal exocytosis. Some of the key steps involved in these important cellular processes, such as vesicular fusion and trafficking, require calcium (Ca2+) signaling. Recent data show that lysosomal functions are transcriptionally regulated by transcription factor EB (TFEB) through the induction of genes involved in lysosomal biogenesis and exocytosis. Given these observations, we investigated the roles of TFEB and lysosomes in intracellular Ca2+ homeostasis. We studied the effect of transient modulation of TFEB expression in HeLa cells by measuring the cytosolic Ca2+ response after capacitative Ca2+ entry activation and Ca2+ dynamics in the endoplasmic reticulum (ER) and directly in lysosomes. Our observations show that transient TFEB overexpression significantly reduces cytosolic Ca2+ levels under a capacitative influx model and ER re-uptake of calcium, increasing the lysosomal Ca2+ buffering capacity. Moreover, lysosomal destruction or damage abolishes these TFEB-dependent effects in both the cytosol and ER. These results suggest a possible Ca2+ buffering role for lysosomes and shed new light on lysosomal functions during intracellular Ca2+ homeostasis.
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Affiliation(s)
- Luigi Sbano
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, 44121, Italy
| | - Massimo Bonora
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, 44121, Italy
| | - Saverio Marchi
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, 44121, Italy
| | - Federica Baldassari
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, 44121, Italy
| | - Diego L Medina
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Naples, Italy
| | - Andrea Ballabio
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Naples, Italy.,Dept. of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA.,Medical Genetics, Dept. of Translational Medicine, Federico II University, 80131 Naples, Italy
| | - Carlotta Giorgi
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, 44121, Italy
| | - Paolo Pinton
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, 44121, Italy
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620
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Enrich C, Rentero C, Meneses-Salas E, Tebar F, Grewal T. Annexins: Ca 2+ Effectors Determining Membrane Trafficking in the Late Endocytic Compartment. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:351-385. [PMID: 29594868 DOI: 10.1007/978-3-319-55858-5_14] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Despite the discovery of annexins 40 years ago, we are just beginning to understand some of the functions of these still enigmatic proteins. Defined and characterized by their ability to bind anionic membrane lipids in a Ca2+-dependent manner, each annexin has to be considered a multifunctional protein, with a multitude of cellular locations and diverse activities. Underlying causes for this considerable functional diversity include their capability to associate with multiple cytosolic and membrane proteins. In recent years, the increasingly recognized establishment of membrane contact sites between subcellular compartments opens a new scenario for annexins as instrumental players to link Ca2+ signalling with the integration of membrane trafficking in many facets of cell physiology. In this chapter, we review and discuss current knowledge on the contribution of annexins in the biogenesis and functioning of the late endocytic compartment, affecting endo- and exocytic pathways in a variety of physiological consequences ranging from membrane repair, lysosomal exocytosis, to cell migration.
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Affiliation(s)
- Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica (CELLEX), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. .,Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica (CELLEX), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Elsa Meneses-Salas
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica (CELLEX), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Francesc Tebar
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica (CELLEX), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, Australia
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621
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Beck A, Fecher-Trost C, Wolske K, Philipp SE, Flockerzi V, Wissenbach U. Identification of Sidt2 as a lysosomal cation-conducting protein. FEBS Lett 2017; 591:76-87. [PMID: 27987306 DOI: 10.1002/1873-3468.12528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 11/25/2016] [Accepted: 12/01/2016] [Indexed: 12/18/2022]
Abstract
A screen to identify lysosomal-expressed ion channels led to the discovery of the human Sidt2 protein. Sidt2 is expressed within lysosomal organelles but as a result of heterologous overexpression the protein is also detectable within the plasma membrane of human embryonic kidney cells. The overexpressed protein leads to cell depolarization upon sodium addition. Accordingly in whole-cell patch clamp experiments a spontaneous noninactivating monovalent cation current can be detected in Sidt2-overexpressing cells. Strong overexpression of Sidt2 in HEK293 cells is attended by a significant reduction/loss of detectable lysosomes, indicating that the overexpressed protein leads to lysosomal dysfunction, a hallmark of Alzheimer's disease. Sidt2 is located on chromosome 11q23, a locus repeatedly found by chromosomal mapping of Alzheimer's disease-related genes.
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Affiliation(s)
- Andreas Beck
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg/Saar, Germany
| | - Claudia Fecher-Trost
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg/Saar, Germany
| | - Karin Wolske
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg/Saar, Germany
| | - Stephan E Philipp
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg/Saar, Germany
| | - Veit Flockerzi
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg/Saar, Germany
| | - Ulrich Wissenbach
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg/Saar, Germany
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622
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Wu B, Yu L, Wang Y, Wang H, Li C, Yin Y, Yang J, Wang Z, Zheng Q, Ma H. Aldehyde dehydrogenase 2 activation in aged heart improves the autophagy by reducing the carbonyl modification on SIRT1. Oncotarget 2016; 7:2175-88. [PMID: 26741505 PMCID: PMC4823027 DOI: 10.18632/oncotarget.6814] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 12/24/2015] [Indexed: 12/31/2022] Open
Abstract
Cardiac aging is characterized by accumulation of damaged proteins and decline of autophagic efficiency. Here, by forestalling SIRT1 carbonylated inactivation in aged heart, we determined the benefits of activation of aldehyde dehydrogenase 2 (ALDH2) on the autophagy. In this study, the ALDH2 KO mice progressively developed age-related heart dysfunction and showed reduction in the life span, which strongly suggests that ALDH2 ablation leads to cardiac aging. What's more, aged hearts displayed a significant decrease ALDH2 activity, resulting in accumulation of 4-HNE-protein adducts and protein carbonyls, impairment in the autophagy flux, and, consequently, deteriorated cardiac function after starvation. Sustained Alda-1 (selective ALDH2 activator) treatment increased cardiac ALDH2 activity and abrogated these effects. Using SIRT1 deficient heterozygous (Sirt1+/−) mice, we found that SIRT1 was necessary for ALDH2 activation-induced autophagy. We further demonstrated that ALDH2 activation attenuated SIRT1 carbonylation and improved SIRT1 activity, thereby increasing the deacetylation of nuclear LC3 and FoxO1. Sequentially, ALDH2 enhanced SIRT1 regulates LC3-Atg7 interaction and FoxO1 increased Rab7 expression, which were both necessary and sufficient for restoring autophagy flux. These results highlight that both accumulation of proteotoxic carbonyl stress linkage with autophagy decline contribute to heart senescence. ALDH2 activation is adequate to improve the autophagy flux by reducing the carbonyl modification on SIRT1, which in turn plays an important role in maintaining cardiac health during aging.
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Affiliation(s)
- Bing Wu
- Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Lu Yu
- Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yishi Wang
- Department of Physiology, School of Basic medicine, Fourth Military Medical University, Xi'an, China
| | - Hongtao Wang
- Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Chen Li
- Department of Physiology, School of Basic medicine, Fourth Military Medical University, Xi'an, China
| | - Yue Yin
- Department of Physiology, School of Basic medicine, Fourth Military Medical University, Xi'an, China.,Department of Pathophysiology, School of Basic medicine, Fourth Military Medical University, Xi'an, China
| | - Jingrun Yang
- Department of Physiology, School of Basic medicine, Fourth Military Medical University, Xi'an, China
| | - Zhifa Wang
- Department of Physiology, School of Basic medicine, Fourth Military Medical University, Xi'an, China
| | - Qiangsun Zheng
- Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Heng Ma
- Department of Physiology, School of Basic medicine, Fourth Military Medical University, Xi'an, China.,Department of Pathophysiology, School of Basic medicine, Fourth Military Medical University, Xi'an, China
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623
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Gómez-Sintes R, Ledesma MD, Boya P. Lysosomal cell death mechanisms in aging. Ageing Res Rev 2016; 32:150-168. [PMID: 26947122 DOI: 10.1016/j.arr.2016.02.009] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 02/22/2016] [Accepted: 02/29/2016] [Indexed: 12/14/2022]
Abstract
Lysosomes are degradative organelles essential for cell homeostasis that regulate a variety of processes, from calcium signaling and nutrient responses to autophagic degradation of intracellular components. Lysosomal cell death is mediated by the lethal effects of cathepsins, which are released into the cytoplasm following lysosomal damage. This process of lysosomal membrane permeabilization and cathepsin release is observed in several physiopathological conditions and plays a role in tissue remodeling, the immune response to intracellular pathogens and neurodegenerative diseases. Many evidences indicate that aging strongly influences lysosomal activity by altering the physical and chemical properties of these organelles, rendering them more sensitive to stress. In this review we focus on how aging alters lysosomal function and increases cell sensitivity to lysosomal membrane permeabilization and lysosomal cell death, both in physiological conditions and age-related pathologies.
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Affiliation(s)
- Raquel Gómez-Sintes
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biologicas, CIB-CSIC, C/Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - María Dolores Ledesma
- Department of Molecular Neurobiology, Centro Biologia Molecular Severo Ochoa, CSIC-UAM, C/Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Patricia Boya
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biologicas, CIB-CSIC, C/Ramiro de Maeztu 9, 28040 Madrid, Spain.
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624
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Loss of Cathepsin B and L Leads to Lysosomal Dysfunction, NPC-Like Cholesterol Sequestration and Accumulation of the Key Alzheimer's Proteins. PLoS One 2016; 11:e0167428. [PMID: 27902765 PMCID: PMC5130271 DOI: 10.1371/journal.pone.0167428] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/14/2016] [Indexed: 01/06/2023] Open
Abstract
Proper function of lysosomes is particularly important in neurons, as they cannot dilute accumulated toxic molecules and aggregates by cell division. Thus, impairment of lysosomal function plays an important role in neuronal degeneration and in the pathogenesis of numerous neurodegenerative diseases. In this work we analyzed how inhibition and/or loss of the major lysosomal proteases, the cysteine cathepsins B and L (CtsB/L), affects lysosomal function, cholesterol metabolism and degradation of the key Alzheimer's disease (AD) proteins. Here, we show that cysteine CtsB/L, and not the aspartyl cathepsin D (CtsD), represent a major lysosomal protease(s) that control lysosomal function, intracellular cholesterol trafficking and AD-like amyloidogenic features. Intriguingly, accumulation of free cholesterol in late endosomes/lysosomes upon CtsB/L inhibition resembled a phenotype characteristic for the rare neurodegenerative disorder Niemann-Pick type C (NPC). CtsB/L inhibition and not the inhibition of CtsD led to lysosomal impairment assessed by decreased degradation of EGF receptor, enhanced LysoTracker staining and accumulation of several lysosomal proteins LC3II, NPC1 and NPC2. By measuring the levels of NPC1 and ABCA1, the two major cholesterol efflux proteins, we showed that CtsB/L inhibition or genetic depletion caused accumulation of the NPC1 in lysosomes and downregulation of ABCA1 protein levels and its expression. Furthermore, we revealed that CtsB/L are involved in degradation of the key Alzheimer's proteins: amyloid-β peptides (Aβ) and C-terminal fragments of the amyloid precursor protein (APP) and in degradation of β-secretase (BACE1). Our results imply CtsB/L as major regulators of lysosomal function and demonstrate that CtsB/L may play an important role in intracellular cholesterol trafficking and in degradation of the key AD proteins. Our findings implicate that enhancing the activity or levels of CtsB/L could provide a promising and a common strategy for maintaining lysosomal function and for preventing and/or treating neurodegenerative diseases.
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625
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Abstract
The ion channel TRPA1 detects noxious stimuli at the plasma membrane of neurons and elicits pain and inflammation. In this issue, Shang et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201603081) report that TRPA1 also localizes to lysosomal membranes of neurons, releasing intracellular Ca2+ to trigger vesicle exocytosis and neuropeptide release.
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Affiliation(s)
- Mingxue Gu
- The Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Haoxing Xu
- The Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
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626
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Abstract
Lysosomes (or lytic bodies) were so named because they contain high levels of hydrolytic enzymes. Lysosome function and dysfunction have been found to play important roles in human disease, including cancer; however, the ways in which lysosomes contribute to tumorigenesis and cancer progression are still being uncovered. Beyond serving as a cellular recycling center, recent evidence suggests that the lysosome is involved in energy homeostasis, generating building blocks for cell growth, mitogenic signaling, priming tissues for angiogenesis and metastasis formation, and activating transcriptional programs. This review examines emerging knowledge of how lysosomal processes contribute to the hallmarks of cancer and highlights vulnerabilities that might be exploited for cancer therapy.
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Affiliation(s)
- Shawn M Davidson
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; , .,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Matthew G Vander Heiden
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; , .,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.,Dana-Farber Cancer Institute, Boston, Massachusetts 02215
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627
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Li X, Ma J. Mitochondria and lysosomes play a key role in HepG2 cell apoptosis induced by microcystin-LR. TOXIN REV 2016. [DOI: 10.1080/15569543.2016.1230133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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628
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Abstract
The lysosome has long been viewed as the recycling center of the cell. However, recent discoveries have challenged this simple view and have established a central role of the lysosome in nutrient-dependent signal transduction. The degradative role of the lysosome and its newly discovered signaling functions are not in conflict but rather cooperate extensively to mediate fundamental cellular activities such as nutrient sensing, metabolic adaptation, and quality control of proteins and organelles. Moreover, lysosome-based signaling and degradation are subject to reciprocal regulation. Transcriptional programs of increasing complexity control the biogenesis, composition, and abundance of lysosomes and fine-tune their activity to match the evolving needs of the cell. Alterations in these essential activities are, not surprisingly, central to the pathophysiology of an ever-expanding spectrum of conditions, including storage disorders, neurodegenerative diseases, and cancer. Thus, unraveling the functions of this fascinating organelle will contribute to our understanding of the fundamental logic of metabolic organization and will point to novel therapeutic avenues in several human diseases.
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Affiliation(s)
- Rushika M Perera
- Department of Anatomy and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, California 94143;
| | - Roberto Zoncu
- Department of Molecular and Cellular Biology and Paul F. Glenn Center for Aging Research, University of California, Berkeley, California 94720;
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629
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Kamiński MM, Liedmann S, Milasta S, Green DR. Polarization and asymmetry in T cell metabolism. Semin Immunol 2016; 28:525-534. [DOI: 10.1016/j.smim.2016.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/06/2016] [Accepted: 10/06/2016] [Indexed: 12/31/2022]
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630
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Li J, Pfeffer SR. Lysosomal membrane glycoproteins bind cholesterol and contribute to lysosomal cholesterol export. eLife 2016; 5:e21635. [PMID: 27664420 PMCID: PMC5068966 DOI: 10.7554/elife.21635] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 09/23/2016] [Indexed: 01/09/2023] Open
Abstract
LAMP1 and LAMP2 proteins are highly abundant, ubiquitous, mammalian proteins that line the lysosome limiting membrane, and protect it from lysosomal hydrolase action. LAMP2 deficiency causes Danon's disease, an X-linked hypertrophic cardiomyopathy. LAMP2 is needed for chaperone-mediated autophagy, and its expression improves tissue function in models of aging. We show here that human LAMP1 and LAMP2 bind cholesterol in a manner that buries the cholesterol 3β-hydroxyl group; they also bind tightly to NPC1 and NPC2 proteins that export cholesterol from lysosomes. Quantitation of cellular LAMP2 and NPC1 protein levels suggest that LAMP proteins represent a significant cholesterol binding site at the lysosome limiting membrane, and may signal cholesterol availability. Functional rescue experiments show that the ability of human LAMP2 to facilitate cholesterol export from lysosomes relies on its ability to bind cholesterol directly.
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Affiliation(s)
- Jian Li
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
| | - Suzanne R Pfeffer
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
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631
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Li Y, Xu M, Ding X, Yan C, Song Z, Chen L, Huang X, Wang X, Jian Y, Tang G, Tang C, Di Y, Mu S, Liu X, Liu K, Li T, Wang Y, Miao L, Guo W, Hao X, Yang C. Protein kinase C controls lysosome biogenesis independently of mTORC1. Nat Cell Biol 2016; 18:1065-77. [PMID: 27617930 DOI: 10.1038/ncb3407] [Citation(s) in RCA: 240] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 08/11/2016] [Indexed: 12/13/2022]
Abstract
Lysosomes respond to environmental cues by controlling their own biogenesis, but the underlying mechanisms are poorly understood. Here we describe a protein kinase C (PKC)-dependent and mTORC1-independent mechanism for regulating lysosome biogenesis, which provides insights into previously reported effects of PKC on lysosomes. By identifying lysosome-inducing compounds we show that PKC couples activation of the TFEB transcription factor with inactivation of the ZKSCAN3 transcriptional repressor through two parallel signalling cascades. Activated PKC inactivates GSK3β, leading to reduced phosphorylation, nuclear translocation and activation of TFEB, while PKC activates JNK and p38 MAPK, which phosphorylate ZKSCAN3, leading to its inactivation by translocation out of the nucleus. PKC activation may therefore mediate lysosomal adaptation to many extracellular cues. PKC activators facilitate clearance of aggregated proteins and lipid droplets in cell models and ameliorate amyloid β plaque formation in APP/PS1 mouse brains. Thus, PKC activators are viable treatment options for lysosome-related disorders.
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Affiliation(s)
- Yang Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Meng Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China.,Graduate University of Chinese Academy of Sciences, Beijing 100039, China
| | - Xiao Ding
- State Key Laboratory of Phytochemistry and Plant Resources in Western China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650021, China
| | - Chen Yan
- The Key Laboratory of Chemistry for Natural Product of Guizhou Province and Chinese Academy of Science, Guiyang 550002, China
| | - Zhiqin Song
- The Key Laboratory of Chemistry for Natural Product of Guizhou Province and Chinese Academy of Science, Guiyang 550002, China
| | - Lianwan Chen
- Key Laboratory of RNA Biology, Beijing Key Laboratory of Noncoding RNA, Institute of Biophysics, Chinese Academy of Sciences, No.15 Datun Road, Chaoyang District, Beijing 100101, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Xin Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Youli Jian
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Guihua Tang
- State Key Laboratory of Phytochemistry and Plant Resources in Western China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650021, China
| | - Changyong Tang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Yingtong Di
- State Key Laboratory of Phytochemistry and Plant Resources in Western China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650021, China
| | - Shuzhen Mu
- The Key Laboratory of Chemistry for Natural Product of Guizhou Province and Chinese Academy of Science, Guiyang 550002, China
| | - Xuezhao Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China.,Graduate University of Chinese Academy of Sciences, Beijing 100039, China
| | - Kai Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China.,Graduate University of Chinese Academy of Sciences, Beijing 100039, China
| | - Ting Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Long Miao
- Key Laboratory of RNA Biology, Beijing Key Laboratory of Noncoding RNA, Institute of Biophysics, Chinese Academy of Sciences, No.15 Datun Road, Chaoyang District, Beijing 100101, China
| | - Weixiang Guo
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
| | - Xiaojiang Hao
- State Key Laboratory of Phytochemistry and Plant Resources in Western China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650021, China.,The Key Laboratory of Chemistry for Natural Product of Guizhou Province and Chinese Academy of Science, Guiyang 550002, China
| | - Chonglin Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
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632
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Qi X, Man SM, Malireddi RKS, Karki R, Lupfer C, Gurung P, Neale G, Guy CS, Lamkanfi M, Kanneganti TD. Cathepsin B modulates lysosomal biogenesis and host defense against Francisella novicida infection. J Exp Med 2016; 213:2081-97. [PMID: 27551156 PMCID: PMC5030800 DOI: 10.1084/jem.20151938] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 07/22/2016] [Indexed: 12/11/2022] Open
Abstract
Kanneganti and collaborators propose that the lysosomal protease cathepsin B provides a checkpoint for activation of the transcription factor TFEB and lysosomal biogenesis and explore the impact of this pathway on host defense against bacterial infection. Lysosomal cathepsins regulate an exquisite range of biological functions, and their deregulation is associated with inflammatory, metabolic, and degenerative diseases in humans. In this study, we identified a key cell-intrinsic role for cathepsin B as a negative feedback regulator of lysosomal biogenesis and autophagy. Mice and macrophages lacking cathepsin B activity had increased resistance to the cytosolic bacterial pathogen Francisella novicida. Genetic deletion or pharmacological inhibition of cathepsin B down-regulated mechanistic target of rapamycin activity and prevented cleavage of the lysosomal calcium channel TRPML1. These events drove transcription of lysosomal and autophagy genes via transcription factor EB, which increased lysosomal biogenesis and activation of autophagy initiation kinase ULK1 for clearance of the bacteria. Our results identified a fundamental biological function of cathepsin B in providing a checkpoint for homeostatic maintenance of lysosome populations and basic recycling functions in the cell.
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Affiliation(s)
- Xiaopeng Qi
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Si Ming Man
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | | | - Rajendra Karki
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Christopher Lupfer
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Prajwal Gurung
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Geoffrey Neale
- Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Clifford S Guy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Mohamed Lamkanfi
- Inflammation Research Center, VIB, B-9052 Zwijnaarde-Ghent, Belgium Department of Internal Medicine, Ghent University, B-9000 Ghent, Belgium
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633
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Autophagosome-lysosome fusion triggers a lysosomal response mediated by TLR9 and controlled by OCRL. Nat Cell Biol 2016; 18:839-850. [PMID: 27398910 PMCID: PMC5040511 DOI: 10.1038/ncb3386] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 06/09/2016] [Indexed: 12/14/2022]
Abstract
Phosphoinositides (PtdIns) control fundamental cell processes, and inherited defects of PtdIns kinases or phosphatases cause severe human diseases, including Lowe syndrome due to mutations in OCRL, which encodes a PtdIns(4,5)P2 5-phosphatase. Here we unveil a lysosomal response to the arrival of autophagosomal cargo in which OCRL plays a key part. We identify mitochondrial DNA and TLR9 as the cargo and the receptor that triggers and mediates, respectively, this response. This lysosome-cargo response is required to sustain the autophagic flux and involves a local increase in PtdIns(4,5)P2 that is confined in space and time by OCRL. Depleting or inhibiting OCRL leads to an accumulation of lysosomal PtdIns(4,5)P2, an inhibitor of the calcium channel mucolipin-1 that controls autophagosome-lysosome fusion. Hence, autophagosomes accumulate in OCRL-depleted cells and in the kidneys of Lowe syndrome patients. Importantly, boosting the activity of mucolipin-1 with selective agonists restores the autophagic flux in cells from Lowe syndrome patients.
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634
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Zhang X, Cheng X, Yu L, Yang J, Calvo R, Patnaik S, Hu X, Gao Q, Yang M, Lawas M, Delling M, Marugan J, Ferrer M, Xu H. MCOLN1 is a ROS sensor in lysosomes that regulates autophagy. Nat Commun 2016; 7:12109. [PMID: 27357649 PMCID: PMC4931332 DOI: 10.1038/ncomms12109] [Citation(s) in RCA: 343] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 05/24/2016] [Indexed: 01/03/2023] Open
Abstract
Cellular stresses trigger autophagy to remove damaged macromolecules and organelles. Lysosomes ‘host' multiple stress-sensing mechanisms that trigger the coordinated biogenesis of autophagosomes and lysosomes. For example, transcription factor (TF)EB, which regulates autophagy and lysosome biogenesis, is activated following the inhibition of mTOR, a lysosome-localized nutrient sensor. Here we show that reactive oxygen species (ROS) activate TFEB via a lysosomal Ca2+-dependent mechanism independent of mTOR. Exogenous oxidants or increasing mitochondrial ROS levels directly and specifically activate lysosomal TRPML1 channels, inducing lysosomal Ca2+ release. This activation triggers calcineurin-dependent TFEB-nuclear translocation, autophagy induction and lysosome biogenesis. When TRPML1 is genetically inactivated or pharmacologically inhibited, clearance of damaged mitochondria and removal of excess ROS are blocked. Furthermore, TRPML1's ROS sensitivity is specifically required for lysosome adaptation to mitochondrial damage. Hence, TRPML1 is a ROS sensor localized on the lysosomal membrane that orchestrates an autophagy-dependent negative-feedback programme to mitigate oxidative stress in the cell. Reactive oxygen species (ROS) damage cell components, necessitating their clearance through autophagy. Here, the authors show that ROS can induce autophagy by triggering TRPML1 to release Ca2+ from the lysosomal lumen, in turn activating the autophagy and lysosomal biogenesis regulator TFEB.
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Affiliation(s)
- Xiaoli Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA
| | - Xiping Cheng
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA
| | - Lu Yu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA
| | - Junsheng Yang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.,Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China
| | - Raul Calvo
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, USA
| | - Samarjit Patnaik
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, USA
| | - Xin Hu
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, USA
| | - Qiong Gao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA
| | - Meimei Yang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA
| | - Maria Lawas
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA
| | - Markus Delling
- The Department of Cardiology, Children's Hospital Boston, Enders 1350, 320 Longwood Avenue, Boston, Massachusetts 02115, USA
| | - Juan Marugan
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, USA
| | - Marc Ferrer
- National Center for Advancing Translational Sciences, National Institute of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, USA
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA
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635
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Exosomes: novel implications in diagnosis and treatment of gastrointestinal cancer. Langenbecks Arch Surg 2016; 401:1097-1110. [PMID: 27342853 DOI: 10.1007/s00423-016-1468-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 06/16/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND Amongst all cancer subtypes, gastrointestinal tumours are responsible for most cancer-related deaths. In most of the cases, the limitation of the prognosis of patients with malignant gastrointestinal tumours can be attributed to delayed diagnosis of the disease. In the last decade, secondary prevention strategies, in particular tumour screenings, have been identified to significantly improve the identification of patients with early-stage disease, leading to more effective therapeutic interventions. Therefore, new screening methods and further innovative treatment approaches may lead to an increase in progression-free and overall survival rates. PURPOSE Exosomes are small microvesicles with a size of 50-150 nm. They are formed in the endosomal system of many different cell types, where they are packed with nucleotides and proteins from the parental cell. After their release into the extracellular space, exosomes can deliver their cargo into recipient cells. By this mechanism, tumour cells can recruit and manipulate the adjacent and systemic microenvironment in order to support invasion and dissemination. Cancer-derived exosomes in the blood may provide detailed information about the tumour biology of each individual patient. Moreover, tumour-derived exosomes can be used as targetable factors and drug delivery agents in clinical practice. CONCLUSION In this review, we summarise new aspects about novel implications in the diagnosis and treatment of gastrointestinal cancer and show how circulating exosomes have come into the spotlight of research as a high potential source of 'liquid biopsies'.
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636
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Abstract
Lipids are essential components of a cell providing energy substrates for cellular processes, signaling intermediates, and building blocks for biological membranes. Lipids are constantly recycled and redistributed within a cell. Lysosomes play an important role in this recycling process that involves the recruitment of lipids to lysosomes via autophagy or endocytosis for their degradation by lysosomal hydrolases. The catabolites produced are redistributed to various cellular compartments to support basic cellular function. Several studies demonstrated a bidirectional relationship between lipids and lysosomes that regulate autophagy. While lysosomal degradation pathways regulate cellular lipid metabolism, lipids also regulate lysosome function and autophagy. In this review, we focus on this bidirectional relationship in the context of dietary lipids and provide an overview of recent evidence of how lipid-overload lipotoxicity, as observed in obesity and metabolic syndrome, impairs lysosomal function and autophagy that may eventually lead to cellular dysfunction or cell death.
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Affiliation(s)
- Bharat Jaishy
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - E Dale Abel
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242
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637
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Mao BH, Tsai JC, Chen CW, Yan SJ, Wang YJ. Mechanisms of silver nanoparticle-induced toxicity and important role of autophagy. Nanotoxicology 2016; 10:1021-40. [DOI: 10.1080/17435390.2016.1189614] [Citation(s) in RCA: 144] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Bin-Hsu Mao
- Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, Tainan City, Taiwan,
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan City, Taiwan ROC,
| | - Jui-Chen Tsai
- Institute of Clinical Pharmacy and Pharmaceutical Sciences, College of Medicine, National Cheng Kung University, Tainan City, Taiwan ROC,
| | - Chun-Wan Chen
- Institute of Labor, Occupational Safety and Health Ministry of Labor, Sijhih District, New Taipei City, Taiwan ROC,
| | - Shian-Jang Yan
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan City, Taiwan ROC,
| | - Ying-Jan Wang
- Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, Tainan City, Taiwan,
- Department of Biomedical Informatics, Asia University, Wufeng District, Taichung City, Taiwan ROC,
- Department of Medical Research, China Medical University Hospital, Taichung City, Taiwan ROC
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638
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Wäster P, Eriksson I, Vainikka L, Rosdahl I, Öllinger K. Extracellular vesicles are transferred from melanocytes to keratinocytes after UVA irradiation. Sci Rep 2016; 6:27890. [PMID: 27293048 PMCID: PMC4904274 DOI: 10.1038/srep27890] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/25/2016] [Indexed: 12/13/2022] Open
Abstract
Ultraviolet (UV) irradiation induces skin pigmentation, which relies on the intercellular crosstalk of melanin between melanocytes to keratinocytes. However, studying the separate effects of UVA and UVB irradiation reveals differences in cellular response. Herein, we show an immediate shedding of extracellular vesicles (EVs) from the plasma membrane when exposing human melanocytes to UVA, but not UVB. The EV-shedding is preceded by UVA-induced plasma membrane damage, which is rapidly repaired by Ca(2+)-dependent lysosomal exocytosis. Using co-cultures of melanocytes and keratinocytes, we show that EVs are preferably endocytosed by keratinocytes. Importantly, EV-formation is prevented by the inhibition of exocytosis and increased lysosomal pH but is not affected by actin and microtubule inhibitors. Melanosome transfer from melanocytes to keratinocytes is equally stimulated by UVA and UVB and depends on a functional cytoskeleton. In conclusion, we show a novel cell response after UVA irradiation, resulting in transfer of lysosome-derived EVs from melanocytes to keratinocytes.
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Affiliation(s)
- Petra Wäster
- Experimental Pathology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Ida Eriksson
- Experimental Pathology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Linda Vainikka
- Experimental Pathology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Inger Rosdahl
- Dermatology and Venereology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Karin Öllinger
- Experimental Pathology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
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639
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Wu L, Sun Y, Ma L, Zhu J, Zhang B, Pan Q, Li Y, Liu H, Diao A, Li Y. A C-terminally truncated mouse Best3 splice variant targets and alters the ion balance in lysosome-endosome hybrids and the endoplasmic reticulum. Sci Rep 2016; 6:27332. [PMID: 27265833 PMCID: PMC4893618 DOI: 10.1038/srep27332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 05/16/2016] [Indexed: 02/07/2023] Open
Abstract
The Bestrophin family has been characterized as Cl(-) channels in mammals and Na(+) channels in bacteria, but their exact physiological roles remian unknown. In this study, a natural C-terminally truncated variant of mouse Bestrophin 3 (Best3V2) expression in myoblasts and muscles is demonstrated. Unlike full-length Best3, Best3V2 targets the two important intracellular Ca stores: the lysosome and the ER. Heterologous overexpression leads to lysosome swelling and renders it less acidic. Best3V2 overexpression also results in compromised Ca(2+) release from the ER. Knocking down endogenous Best3 expression in myoblasts makes these cells more excitable in response to Ca(2+) mobilizing reagents, such as caffeine. We propose that Best3V2 in myoblasts may work as a tuner to control Ca(2+) release from intracellular Ca(2+) stores.
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Affiliation(s)
- Lichang Wu
- Department of Animal Sciences and Technology, Qingdao Agricultural University, Qingdao, China.,College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Yu Sun
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Liqiao Ma
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Jun Zhu
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Baoxia Zhang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Qingjie Pan
- Department of Animal Sciences and Technology, Qingdao Agricultural University, Qingdao, China
| | - Yuyin Li
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Huanqi Liu
- Department of Animal Sciences and Technology, Qingdao Agricultural University, Qingdao, China
| | - Aipo Diao
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Yinchuan Li
- Department of Animal Sciences and Technology, Qingdao Agricultural University, Qingdao, China
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640
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Abstract
Lysosomes are key acidic Ca2+ stores. The principle Ca2+-permeable channels of the lysosome are TRP mucolipins (TRPMLs) and NAADP-regulated two-pore channels (TPCs). Recent studies, reviewed in this collection, have linked numerous neurodegenerative diseases to both gain and loss of function of TRPMLs/TPCs, as well as to defects in acidic Ca2+ store content. These diseases span rare lysosomal storage disorders such as Mucolipidosis Type IV and Niemann-Pick disease, type C, through to more common ones such as Alzheimer and Parkinson disease. Cellular phenotypes, underpinned by endo-lysosomal trafficking defects, are reversed by chemical or molecular targeting of TRPMLs and TPCs. Lysosomal Ca2+ channels therefore emerge as potential druggable targets in combatting neurodegeneration.
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Affiliation(s)
- Sandip Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT
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641
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Feng X, Yang J. Lysosomal Calcium in Neurodegeneration. MESSENGER (LOS ANGELES, CALIF. : PRINT) 2016; 5:56-66. [PMID: 29082116 PMCID: PMC5659362 DOI: 10.1166/msr.2016.1055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Lysosomes are the central organelles responsible for macromolecule recycling in the cell. Lysosomal dysfunction is the primary cause of lysosomal storage diseases (LSDs), and contributes significantly to the pathogenesis of common neurodegenerative diseases. The lysosomes are also intracellular stores for calcium ions, one of the most common second messenger in the cell. Lysosomal Ca2+ is required for diverse cellular processes including signal transduction, vesicular trafficking, autophagy, nutrient sensing, exocytosis, and membrane repair. In this review, we first summarize some recent progresses in the studies of lysosome Ca2+ regulation, with a focus on the newly discovered lysosomal Ca2+ channels and the mechanisms of lysosomal Ca2+ store refilling. We then discuss how defects in lysosomal Ca2+ release and store maintenance cause lysosomal dysfunction and neurodegeneration.
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Affiliation(s)
- Xinghua Feng
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China
| | - Junsheng Yang
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China
- The Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
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642
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Garrity AG, Wang W, Collier CM, Levey SA, Gao Q, Xu H. The endoplasmic reticulum, not the pH gradient, drives calcium refilling of lysosomes. eLife 2016; 5. [PMID: 27213518 PMCID: PMC4909396 DOI: 10.7554/elife.15887] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/20/2016] [Indexed: 12/15/2022] Open
Abstract
Impaired homeostasis of lysosomal Ca2+ causes lysosome dysfunction and lysosomal storage diseases (LSDs), but the mechanisms by which lysosomes acquire and refill Ca2+ are not known. We developed a physiological assay to monitor lysosomal Ca2+ store refilling using specific activators of lysosomal Ca2+ channels to repeatedly induce lysosomal Ca2+ release. In contrast to the prevailing view that lysosomal acidification drives Ca2+ into the lysosome, inhibiting the V-ATPase H+ pump did not prevent Ca2+ refilling. Instead, pharmacological depletion or chelation of Endoplasmic Reticulum (ER) Ca2+ prevented lysosomal Ca2+ stores from refilling. More specifically, antagonists of ER IP3 receptors (IP3Rs) rapidly and completely blocked Ca2+ refilling of lysosomes, but not in cells lacking IP3Rs. Furthermore, reducing ER Ca2+ or blocking IP3Rs caused a dramatic LSD-like lysosome storage phenotype. By closely apposing each other, the ER may serve as a direct and primary source of Ca2+for the lysosome. DOI:http://dx.doi.org/10.7554/eLife.15887.001
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Affiliation(s)
- Abigail G Garrity
- Neuroscience Program, University of Michigan, Ann Arbor, United States
| | - Wuyang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Crystal Md Collier
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Sara A Levey
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Qiong Gao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Haoxing Xu
- Neuroscience Program, University of Michigan, Ann Arbor, United States.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
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643
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Kivinen N, Felszeghy S, Kinnunen AI, Setälä N, Aikio M, Kinnunen K, Sironen R, Pihlajaniemi T, Kauppinen A, Kaarniranta K. Absence of collagen XVIII in mice causes age-related insufficiency in retinal pigment epithelium proteostasis. Biogerontology 2016; 17:749-61. [DOI: 10.1007/s10522-016-9647-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 04/21/2016] [Indexed: 01/26/2023]
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644
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Abstract
Extracellular stimuli evoke the synthesis of intracellular second messengers, several of which couple to the release of Ca2+ from Ca2+-storing organelles via activation of cognate organellar Ca2+-channel complexes. The archetype is the inositol 1,4,5-trisphosphate (IP3) and IP3 receptor (IP3R) on the endoplasmic reticulum (ER). A less understood, parallel Ca2+ signalling cascade is that involving the messenger nicotinic acid adenine dinucleotide phosphate (NAADP) that couples to Ca2+ release from acidic Ca2+ stores [e.g. endo-lysosomes, secretory vesicles, lysosome-related organelles (LROs)]. NAADP-induced Ca2+ release absolutely requires organellar TPCs (two-pore channels). This review discusses how ER and acidic Ca2+ stores physically and functionally interact to generate and shape global and local Ca2+ signals, with particular emphasis on the two-way dialogue between these two organelles.
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645
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Goldman-Pinkovich A, Balno C, Strasser R, Zeituni-Molad M, Bendelak K, Rentsch D, Ephros M, Wiese M, Jardim A, Myler PJ, Zilberstein D. An Arginine Deprivation Response Pathway Is Induced in Leishmania during Macrophage Invasion. PLoS Pathog 2016; 12:e1005494. [PMID: 27043018 PMCID: PMC4846328 DOI: 10.1371/journal.ppat.1005494] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 02/15/2016] [Indexed: 11/18/2022] Open
Abstract
Amino acid sensing is an intracellular function that supports nutrient homeostasis, largely through controlled release of amino acids from lysosomal pools. The intracellular pathogen Leishmania resides and proliferates within human macrophage phagolysosomes. Here we describe a new pathway in Leishmania that specifically senses the extracellular levels of arginine, an amino acid that is essential for the parasite. During infection, the macrophage arginine pool is depleted due to its use to produce metabolites (NO and polyamines) that constitute part of the host defense response and its suppression, respectively. We found that parasites respond to this shortage of arginine by up-regulating expression and activity of the Leishmania arginine transporter (LdAAP3), as well as several other transporters. Our analysis indicates the parasite monitors arginine levels in the environment rather than the intracellular pools. Phosphoproteomics and genetic analysis indicates that the arginine-deprivation response is mediated through a mitogen-activated protein kinase-2-dependent signaling cascade. Protozoa of the genus Leishmania are the causative agents of leishmaniasis in humans. These parasites cycle between promastigotes in the sand fly mid-gut and amastigotes in phagolysosome of mammalian macrophages. During infection, host cells up-regulate nitric oxide while/or parasites induce expression of host arginase, both of which use arginine as a substrate. These elevated activities deplete macrophage arginine pools, a situation that invading Leishmania must overcome since it is an essential amino acid. Leishmania donovani imports exogenous arginine via a mono-specific amino acid transporter (AAP3) and utilizes it primarily through the polyamine pathway to provide precursors for trypanothione biosynthesis as well as hypusination of eukaryotic translation Initiation Factor 5A. Here we report the discovery of a pathway whereby Leishmania sense the lack of environmental arginine and respond with rapid up-regulation in the expression and activity of AAP3, as well as several other transporters. Significantly, this arginine deprivation response is also activated in parasites during macrophage infection. Phosphoproteomic analyses of L. donovani promastigotes have implicated a mitogen-activated protein kinase 2 (MPK2)-mediated signaling cascade in this response, and L. mexicana mutants lacking MPK2 are unable to respond to arginine deprivation. The arginine-sensing pathway might play an important role in Leishmania virulence and hence serve as target for drug development.
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Affiliation(s)
| | - Caitlin Balno
- Faculty of Biology, Technion—Israel Institute of Technology, Haifa, Haifa, Israel
| | - Rona Strasser
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, Quebec, Canada
| | - Michal Zeituni-Molad
- Carmel Medical Center and Faculty of Medicine, Technion,—Israel institute of Technology, Haifa, Israel
| | - Keren Bendelak
- The Smoler Proteomic Center, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Moshe Ephros
- Carmel Medical Center and Faculty of Medicine, Technion,—Israel institute of Technology, Haifa, Israel
| | - Martin Wiese
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Armando Jardim
- Institute of Parasitology, McGill University, Ste Anne de Bellevue, Quebec, Canada
| | - Peter J. Myler
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, Washington, United States of America
- Departments of Global Health and Biomedical Informatics & Medical Education, University of Washington, Seattle, Washington, United States of America
| | - Dan Zilberstein
- Faculty of Biology, Technion—Israel Institute of Technology, Haifa, Haifa, Israel
- * E-mail:
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646
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Affiliation(s)
- Malini Ahuja
- a Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda , MD , USA
| | - Soonhong Park
- b Department of Oral Biology , BK 21 PLUS Project, Yonsei University College of Dentistry , Seoul , Korea
| | - Dong Min Shin
- b Department of Oral Biology , BK 21 PLUS Project, Yonsei University College of Dentistry , Seoul , Korea
| | - Shmuel Muallem
- a Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda , MD , USA
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647
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Duda J, Pötschke C, Liss B. Converging roles of ion channels, calcium, metabolic stress, and activity pattern of Substantia nigra dopaminergic neurons in health and Parkinson's disease. J Neurochem 2016; 139 Suppl 1:156-178. [PMID: 26865375 PMCID: PMC5095868 DOI: 10.1111/jnc.13572] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/03/2016] [Accepted: 02/05/2016] [Indexed: 12/18/2022]
Abstract
Dopamine‐releasing neurons within the Substantia nigra (SN DA) are particularly vulnerable to degeneration compared to other dopaminergic neurons. The age‐dependent, progressive loss of these neurons is a pathological hallmark of Parkinson's disease (PD), as the resulting loss of striatal dopamine causes its major movement‐related symptoms. SN DA neurons release dopamine from their axonal terminals within the dorsal striatum, and also from their cell bodies and dendrites within the midbrain in a calcium‐ and activity‐dependent manner. Their intrinsically generated and metabolically challenging activity is created and modulated by the orchestrated function of different ion channels and dopamine D2‐autoreceptors. Here, we review increasing evidence that the mechanisms that control activity patterns and calcium homeostasis of SN DA neurons are not only crucial for their dopamine release within a physiological range but also modulate their mitochondrial and lysosomal activity, their metabolic stress levels, and their vulnerability to degeneration in PD. Indeed, impaired calcium homeostasis, lysosomal and mitochondrial dysfunction, and metabolic stress in SN DA neurons represent central converging trigger factors for idiopathic and familial PD. We summarize double‐edged roles of ion channels, activity patterns, calcium homeostasis, and related feedback/feed‐forward signaling mechanisms in SN DA neurons for maintaining and modulating their physiological function, but also for contributing to their vulnerability in PD‐paradigms. We focus on the emerging roles of maintained neuronal activity and calcium homeostasis within a physiological bandwidth, and its modulation by PD‐triggers, as well as on bidirectional functions of voltage‐gated L‐type calcium channels and metabolically gated ATP‐sensitive potassium (K‐ATP) channels, and their probable interplay in health and PD.
We propose that SN DA neurons possess several feedback and feed‐forward mechanisms to protect and adapt their activity‐pattern and calcium‐homeostasis within a physiological bandwidth, and that PD‐trigger factors can narrow this bandwidth. We summarize roles of ion channels in this view, and findings documenting that both, reduced as well as elevated activity and associated calcium‐levels can trigger SN DA degeneration.
This article is part of a special issue on Parkinson disease.
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Affiliation(s)
- Johanna Duda
- Department of Applied Physiology, Ulm University, Ulm, Germany
| | | | - Birgit Liss
- Department of Applied Physiology, Ulm University, Ulm, Germany.
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648
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Checchetto V, Teardo E, Carraretto L, Leanza L, Szabo I. Physiology of intracellular potassium channels: A unifying role as mediators of counterion fluxes? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1258-1266. [PMID: 26970213 DOI: 10.1016/j.bbabio.2016.03.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 03/06/2016] [Accepted: 03/07/2016] [Indexed: 12/28/2022]
Abstract
Plasma membrane potassium channels importantly contribute to maintain ion homeostasis across the cell membrane. The view is emerging that also those residing in intracellular membranes play pivotal roles for the coordination of correct cell function. In this review we critically discuss our current understanding of the nature and physiological tasks of potassium channels in organelle membranes in both animal and plant cells, with a special emphasis on their function in the regulation of photosynthesis and mitochondrial respiration. In addition, the emerging role of potassium channels in the nuclear membranes in regulating transcription will be discussed. The possible functions of endoplasmic reticulum-, lysosome- and plant vacuolar membrane-located channels are also referred to. Altogether, experimental evidence obtained with distinct channels in different membrane systems points to a possible unifying function of most intracellular potassium channels in counterbalancing the movement of other ions including protons and calcium and modulating membrane potential, thereby fine-tuning crucial cellular processes. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-7, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Vanessa Checchetto
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy; Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, Padova 35131 Italy
| | - Enrico Teardo
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Luca Carraretto
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Luigi Leanza
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy; CNR Institute of Neuroscience, University of Padova, Viale G. Colombo 3, Padova 35131, Italy.
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649
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A molecular mechanism to regulate lysosome motility for lysosome positioning and tubulation. Nat Cell Biol 2016; 18:404-17. [PMID: 26950892 PMCID: PMC4871318 DOI: 10.1038/ncb3324] [Citation(s) in RCA: 276] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/04/2016] [Indexed: 12/12/2022]
Abstract
To mediate the degradation of bio-macromolecules, lysosomes must traffic towards cargo-carrying vesicles for subsequent membrane fusion or fission. Mutations of the lysosomal Ca2+ channel TRPML1 cause lysosome storage disease (LSD) characterized by disordered lysosomal membrane trafficking in cells. Here we show that TRPML1 activity is required to promote Ca2+-dependent centripetal movement of lysosomes towards the perinuclear region, where autophagosomes accumulate, upon autophagy induction. ALG-2, an EF-hand-containing protein, serves as a lysosomal Ca2+ sensor that associates physically with the minus-end directed dynactin-dynein motor, while PI(3,5)P2, a lysosome-localized phosphoinositide, acts upstream of TRPML1. Furthermore, the PI(3,5)P2-TRPML1-ALG-2-dynein signaling is necessary for lysosome tubulation and reformation. In contrast, the TRPML1 pathway is not required for the perinuclear accumulation of lysosomes observed in many LSDs, which is instead likely caused by secondary cholesterol accumulation that constitutively activates Rab7-RILP-dependent retrograde transport. Collectively, Ca2+ release from lysosomes provides an on-demand mechanism regulating lysosome motility, positioning, and tubulation.
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650
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Hämälistö S, Jäättelä M. Lysosomes in cancer-living on the edge (of the cell). Curr Opin Cell Biol 2016; 39:69-76. [PMID: 26921697 DOI: 10.1016/j.ceb.2016.02.009] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 12/25/2022]
Abstract
The lysosomes have definitely polished their status inside the cell. Being discovered as the last resort of discarded cellular biomass, the steady rising of this versatile signaling organelle is currently ongoing. This review discusses the recent data on the unconventional functions of lysosomes, focusing mainly on the less studied lysosomes residing in the cellular periphery. We emphasize our discussion on the emerging paths the lysosomes have taken in promoting cancer progression to metastatic disease. Finally, we address how the altered cancerous lysosomes in metastatic cancers may be specifically targeted and what are the pending questions awaiting for elucidation.
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Affiliation(s)
- Saara Hämälistö
- Cell Death and Metabolism Unit, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Marja Jäättelä
- Cell Death and Metabolism Unit, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark.
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