1
|
Xu Y, Liu W, Sun Z, Yu Y, Yang T, Lu X, Zhang G, Jiao J, Duan X. The two autophagy-related proteins 8a and 8b play distinct physiological roles in Drosophila. Genomics 2024; 116:110853. [PMID: 38701988 DOI: 10.1016/j.ygeno.2024.110853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 04/17/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Atg8 family proteins play crucial roles in autophagy to maintain cellular homeostasis. However, the physiological roles of Atg8 family proteins have not been systematically determined. In this study, we generated Atg8a and Atg8b (homologs of Atg8 in Drosophila melanogaster) knockout flies. We found that the loss of Atg8a affected autophagy and resulted in partial lethality, abnormal wings, decreased lifespan, and decreased climbing ability in flies. Furthermore, the loss of Atg8a resulted in reduced muscle integrity and the progressive degeneration of the neuron system. We also found that the phosphorylation at Ser88 of Atg8a is important for autophagy and neuronal integrity. The loss of Atg8b did not affect autophagy but induced male sterility in flies. Here, we take full advantage of the fly system to elucidate the physiological function of Atg8a and Atg8b in Drosophila.
Collapse
Affiliation(s)
- Yuchen Xu
- School of Life Sciences, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, China
| | - Wei Liu
- College of Basic Medicine, Xuzhou Medical University, Xuzhou 221004, China
| | - Zhaolin Sun
- School of Life Sciences, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, China
| | - Yurun Yu
- School of Life Sciences, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, China
| | - Tianhao Yang
- School of Life Sciences, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, China
| | - Xirui Lu
- School of Life Sciences, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, China
| | - Guiqiang Zhang
- School of Life Sciences, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, China
| | - Jianwei Jiao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Xiuying Duan
- School of Life Sciences, Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, China.
| |
Collapse
|
2
|
Wang J, Su Q, Chen K, Wu Q, Ren J, Tang W, Hu Y, Zhu Z, Cheng C, Tu K, He H, Zhang Y. Pyrimethamine upregulates BNIP3 to interfere SNARE-mediated autophagosome-lysosomal fusion in hepatocellular carcinoma. J Pharm Anal 2024; 14:211-224. [PMID: 38464783 PMCID: PMC10921246 DOI: 10.1016/j.jpha.2023.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/13/2023] [Accepted: 05/29/2023] [Indexed: 03/12/2024] Open
Abstract
Hepatocellular carcinoma (HCC) is one of the most common tumor types and remains a major clinical challenge. Increasing evidence has revealed that mitophagy inhibitors can enhance the effect of chemotherapy on HCC. However, few mitophagy inhibitors have been approved for clinical use in humans. Pyrimethamine (Pyr) is used to treat infections caused by protozoan parasites. Recent studies have reported that Pyr may be beneficial in the treatment of various tumors. However, its mechanism of action is still not clearly defined. Here, we found that blocking mitophagy sensitized cells to Pyr-induced apoptosis. Mechanistically, Pyr potently induced the accumulation of autophagosomes by inhibiting autophagosome-lysosome fusion in human HCC cells. In vitro and in vivo studies revealed that Pyr blocked autophagosome-lysosome fusion by upregulating BNIP3 to inhibit synaptosomal-associated protein 29 (SNAP29)-vesicle-associated membrane protein 8 (VAMP8) interaction. Moreover, Pyr acted synergistically with sorafenib (Sora) to induce apoptosis and inhibit HCC proliferation in vitro and in vivo. Pyr enhances the sensitivity of HCC cells to Sora, a common chemotherapeutic, by inhibiting mitophagy. Thus, these results provide new insights into the mechanism of action of Pyr and imply that Pyr could potentially be further developed as a novel mitophagy inhibitor. Notably, Pyr and Sora combination therapy could be a promising treatment for malignant HCC.
Collapse
Affiliation(s)
- Jingjing Wang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Qi Su
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Kun Chen
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Qing Wu
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Jiayan Ren
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Wenjuan Tang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Yu Hu
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Zeren Zhu
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Cheng Cheng
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Kaihui Tu
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Huaizhen He
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Yanmin Zhang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, 710061, China
| |
Collapse
|
3
|
Linnert J, Güler BE, Krzysko J, Wolfrum U. The adhesion G protein-coupled receptor VLGR1/ADGRV1 controls autophagy. Basic Clin Pharmacol Toxicol 2023; 133:313-330. [PMID: 37002809 DOI: 10.1111/bcpt.13869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/27/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
VLGR1/ADGRV1 (very large G protein-coupled receptor-1) is the largest known adhesion G protein-coupled receptor. Mutations in VLGR1/ADGRV1 cause Usher syndrome (USH), the most common form of hereditary deaf-blindness, and have been additionally linked to epilepsy. Although VLGR1/ADGRV1 is almost ubiquitously expressed, little is known about the subcellular function and signalling of the VLGR1 protein and thus about mechanisms underlying the development of diseases. Using affinity proteomics, we identified key components of autophagosomes as putative interacting proteins of VLGR1. In addition, whole transcriptome sequencing of the retinae of the Vlgr1/del7TM mouse model revealed altered expression profiles of gene-related autophagy. Monitoring autophagy by immunoblotting and immunocytochemistry of the LC3 and p62 as autophagy marker proteins revealed evoked autophagy in VLGR1-deficient hTERT-RPE1 cells and USH2C patient-derived fibroblasts. Our data demonstrate the molecular and functional interaction of VLGR1 with key components of the autophagy process and point to an essential role of VLGR1 in the regulation of autophagy at internal membranes. The close association of VLGR1 with autophagy helps to explain the pathomechanisms underlying human USH and epilepsy related to VLGR1 defects.
Collapse
Affiliation(s)
- Joshua Linnert
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Baran E Güler
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Jacek Krzysko
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| |
Collapse
|
4
|
Zhang S, Yi S, Wang L, Li S, Wang H, Song L, Ou J, Zhang M, Wang R, Wang M, Zheng Y, Yang K, Liu T, Ho MS. Cyclin-G-associated kinase GAK/dAux regulates autophagy initiation via ULK1/Atg1 in glia. Proc Natl Acad Sci U S A 2023; 120:e2301002120. [PMID: 37428930 PMCID: PMC10629559 DOI: 10.1073/pnas.2301002120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 06/08/2023] [Indexed: 07/12/2023] Open
Abstract
Autophagy is a major means for the elimination of protein inclusions in neurons in neurodegenerative diseases such as Parkinson's disease (PD). Yet, the mechanism of autophagy in the other brain cell type, glia, is less well characterized and remains largely unknown. Here, we present evidence that the PD risk factor, Cyclin-G-associated kinase (GAK)/Drosophila homolog Auxilin (dAux), is a component in glial autophagy. The lack of GAK/dAux increases the autophagosome number and size in adult fly glia and mouse microglia, and generally up-regulates levels of components in the initiation and PI3K class III complexes. GAK/dAux interacts with the master initiation regulator UNC-51like autophagy activating kinase 1/Atg1 via its uncoating domain and regulates the trafficking of Atg1 and Atg9 to autophagosomes, hence controlling the onset of glial autophagy. On the other hand, lack of GAK/dAux impairs the autophagic flux and blocks substrate degradation, suggesting that GAK/dAux might play additional roles. Importantly, dAux contributes to PD-like symptoms including dopaminergic neurodegeneration and locomotor function in flies. Our findings identify an autophagy factor in glia; considering the pivotal role of glia under pathological conditions, targeting glial autophagy is potentially a therapeutic strategy for PD.
Collapse
Affiliation(s)
- Shiping Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| | - Shuanglong Yi
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Linfang Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Shuhua Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| | - Honglei Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| | - Li Song
- Department of Anatomy and Neurobiology, Tongji University School of Medicine, Shanghai200092, China
| | - Jiayao Ou
- Department of Anatomy and Neurobiology, Tongji University School of Medicine, Shanghai200092, China
| | - Min Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| | - Ruiqi Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| | - Mengxiao Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| | - Yuchen Zheng
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| | - Kai Yang
- International Academic Center of Complex Systems, Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai, Zhuhai519087, China
| | - Tong Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Chinese Academy of Sciences Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai200031, China
| | - Margaret S. Ho
- School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| |
Collapse
|
5
|
Feng L, Lu CK, Wu J, Chan LL, Yue J. Identification of Anhydrodebromoaplysiatoxin as a Dichotomic Autophagy Inhibitor. Mar Drugs 2023; 21:46. [PMID: 36662219 PMCID: PMC9862050 DOI: 10.3390/md21010046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/30/2022] [Accepted: 01/04/2023] [Indexed: 01/13/2023] Open
Abstract
Dysfunctional autophagy is associated with various human diseases, e.g., cancer. The discovery of small molecules modulating autophagy with therapeutic potential could be significant. To this end, we screened the ability of a series of metabolites isolated from marine microorganisms to modulate autophagy. Anhydrodebromoaplysiatoxin (ADAT), a metabolite yielded by the marine red algae Gracilaria coronopifolia, inhibited autophagosome-lysosome fusion in mammalian cells, thereby inducing the accumulation of autophagosomes. Treatment of cells with ADAT alkalinized lysosomal pH. Interestingly, ADAT also activated the mTOR/p70S6K/FoxO3a signaling pathway, likely leading to the inhibition of autophagy induction. ADAT had little effect on apoptosis. Our results suggest that ADAT is a dichotomic autophagy inhibitor that inhibits both late-stage (autophagosome-lysosome fusion) and early-stage (autophagy induction) autophagy.
Collapse
Affiliation(s)
- Limin Feng
- Shenzhen Key Laboratory in Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518000, China
| | - Chung-Kuang Lu
- National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei 11221, Taiwan
- Department of Bioscience and Institute of Genomics, National Yang Ming University, Taipei 11221, Taiwan
| | - Jiajun Wu
- Shenzhen Key Laboratory in Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518000, China
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong SAR 999077, China
| | - Leo Lai Chan
- Shenzhen Key Laboratory in Sustainable Use of Marine Biodiversity, Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518000, China
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong SAR 999077, China
- Department of Biomedical Science, City University of Hong Kong, Hong Kong SAR 999077, China
| | - Jianbo Yue
- Division of Natural and Applied Sciences, Synear Molecular Biology Lab, Duke Kunshan University, Kunshan 215316, China
| |
Collapse
|
6
|
CUR5g, a novel autophagy inhibitor, exhibits potent synergistic anticancer effects with cisplatin against non-small-cell lung cancer. Cell Death Dis 2022; 8:435. [PMCID: PMC9622744 DOI: 10.1038/s41420-022-01217-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/08/2022]
Abstract
Autophagy, a highly conserved degradation process of eukaryotic cells, has been proven to be closely related to chemoresistance and metastasis of non-small-cell lung cancer (NSCLC). Autophagy inhibitors, such as chloroquine (CQ) and its derivative hydroxychloroquine (HCQ), has been shown to mediate anticancer effects in preclinical models, especially when combined with chemotherapy. However, the vast majority of autophagy inhibitors, including CQ and HCQ, actually disrupt lysosomal or/and possibly non-lysosomal processes other than autophagy. It is therefore of great significance to discover more specific autophagy inhibitors. In this study, after screening a series of curcumin derivatives synthesized in our laboratory, we found that (3E,5E)-1-methyl-3-(4-hydroxybenzylidene)-5-(3-indolymethylene)-piperidine-4-one (CUR5g) selectively inhibited autophagosome degradation in cancer cells by blocking autophagosome-lysosome fusion. CUR5g did not affect the lysosomal pH and proteolytic function, nor did it disturb cytoskeleton. CUR5g blocked the recruitment of STX17, a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein, to autophagosomes via a UVRAG-dependent mechanism, resulting in the inability of autophagosomes to fuse with lysosomes. CUR5g alone did not induce apoptosis and necrosis of A549 cells, but significantly inhibited the mobility and colony formation of A549 cells. More excitingly, CUR5g showed no obvious toxicity to normal HUVECs in vitro or mice in vivo. CUR5g enhances the cisplatin sensitivity of A549 cells and effectively inhibited autophagy in tumor tissues in vivo. Collectively, our study identified a new late-stage autophagy inhibitor and provided a novel option for NSCLC treatment, particular when combined with cisplatin.
Collapse
|
7
|
Saikia R, Joseph J. AMPK: a key regulator of energy stress and calcium-induced autophagy. J Mol Med (Berl) 2021; 99:1539-1551. [PMID: 34398293 DOI: 10.1007/s00109-021-02125-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 02/07/2023]
Abstract
Autophagy is a well-known cell-survival strategy orchestrated by a conserved set of proteins. It equips the cells with mechanisms to attain homeostasis during unfavorable conditions such as stress by breaking down the cellular components and reusing them for energy as well as for building new components required for survival. A basal level of autophagy is required for achieving homeostasis under normal conditions through regular turnover of macromolecules and organelles. Initiation of autophagy is regulated by two key components of the nutrient/energy sensor pathways; mammalian target of rapamycin 1 (mTORC1) and AMP-activated kinase (AMPK). Under energy-deprived conditions, AMPK is activated triggering autophagy, whereas, in nutrient-rich conditions, the growth-promoting kinase mTORC1 is activated inhibiting autophagy. Thus, the reciprocal regulation of autophagy by AMPK and mTORC1 defines a fundamental mechanism by which cells respond to nutrient availability. Interestingly, cytoplasmic calcium is also found to be an activator of AMPK and autophagy through a calmodulin/CaMKKβ pathway. However, the physiological significance of the regulation of autophagy by cytoplasmic calcium is currently unclear. This review focuses on the current understanding of the mechanism of autophagy and its regulation by AMPK.
Collapse
Affiliation(s)
- Rimpi Saikia
- National Centre for Cell Science, S. P. Pune University Campus, Pune, 411007, Maharashtra State, India
| | - Jomon Joseph
- National Centre for Cell Science, S. P. Pune University Campus, Pune, 411007, Maharashtra State, India.
| |
Collapse
|
8
|
Zhang L, Fang Y, Zhao X, Zheng Y, Ma Y, Li S, Huang Z, Li L. BRUCE silencing leads to axonal dystrophy by repressing autophagosome-lysosome fusion in Alzheimer's disease. Transl Psychiatry 2021; 11:421. [PMID: 34354038 PMCID: PMC8342531 DOI: 10.1038/s41398-021-01427-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/24/2021] [Accepted: 05/06/2021] [Indexed: 11/10/2022] Open
Abstract
Axonal dystrophy is a swollen and tortuous neuronal process that contributes to synaptic alterations occurring in Alzheimer's disease (AD). Previous study identified that brain-derived neurotrophic factor (BDNF) binds to tropomyosin-related kinase B (TrkB) at the axon terminal and then the signal is propagated along the axon to the cell body and affects neuronal function through retrograde transport. Therefore, this study was designed to identify a microRNA (miRNA) that alters related components of the transport machinery to affect BDNF retrograde signaling deficits in AD. Hippocampus tissues were isolated from APP/PS1 transgenic (AD-model) mice and C57BL/6J wild-type mice and subject to nicotinamide adenine dinucleotide phosphate and immunohistochemical staining. Autophagosome-lysosome fusion and nuclear translocation of BDNF was detected using immunofluorescence in HT22 cells. The interaction among miR-204, BIR repeat containing ubiquitin-conjugating enzyme (BRUCE) and Syntaxin 17 (STX17) was investigated using dual luciferase reporter gene assay and co-immunoprecipitation assay. The expression of relevant genes and proteins were determined by RT-qPCR and Western blot analysis. Knockdown of STX17 or BRUCE inhibited autophagosome-lysosome fusion and impacted axon growth in HT22 cells. STX17 immunoprecipitating with BRUCE and co-localization of them demonstrated BRUCE interacted with STX17. BRUCE was the target of miR-204, and partial loss of miR-204 by inhibitor promoted autophagosome-lysosome fusion to prevent axon dystrophy and accumulated BDNF nuclear translocation to rescue BDNF/TrkB signaling deficits in HT22 cells. The overall results demonstrated that inhibition of miR-204 prevents axonal dystrophy by blocking BRUCE interaction with STX17, which unraveled potential novel therapeutic targets for delaying AD.
Collapse
Affiliation(s)
- Lu Zhang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, P.R. China.
| | - Yu Fang
- grid.412633.1ICU, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 P.R. China
| | - Xinyu Zhao
- grid.412633.1Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 P.R. China
| | - Yake Zheng
- grid.412633.1Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 P.R. China
| | - Yunqing Ma
- grid.412633.1Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 P.R. China
| | - Shuang Li
- grid.412633.1Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 P.R. China
| | - Zhi Huang
- grid.412633.1Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 P.R. China
| | - Lihao Li
- grid.412633.1Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 P.R. China
| |
Collapse
|
9
|
Tang BL. Syntaxin 16's Newly Deciphered Roles in Autophagy. Cells 2019; 8:cells8121655. [PMID: 31861136 PMCID: PMC6953085 DOI: 10.3390/cells8121655] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 12/16/2022] Open
Abstract
Syntaxin 16, a Qa-SNARE (soluble N-ethylmaleimide-sensitive factor activating protein receptor), is involved in a number of membrane-trafficking activities, particularly transport processes at the trans-Golgi network (TGN). Recent works have now implicated syntaxin 16 in the autophagy process. In fact, syntaxin 16 appears to have dual roles, firstly in facilitating the transport of ATG9a-containing vesicles to growing autophagosomes, and secondly in autolysosome formation. The former involves a putative SNARE complex between syntaxin 16, VAMP7 and SNAP-47. The latter occurs via syntaxin 16’s recruitment by Atg8/LC3/GABARAP family proteins to autophagosomes and endo-lysosomes, where syntaxin 16 may act in a manner that bears functional redundancy with the canonical autophagosome Qa-SNARE syntaxin 17. Here, I discuss these recent findings and speculate on the mechanistic aspects of syntaxin 16’s newly found role in autophagy.
Collapse
Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore; ; Tel.: +65-6516-1040
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 119077, Singapore
| |
Collapse
|
10
|
Aivazidis S, Jain A, Rauniyar AK, Anderson CC, Marentette JO, Orlicky DJ, Fritz KS, Harris PS, Siegel D, Maclean KN, Roede JR. SNARE proteins rescue impaired autophagic flux in Down syndrome. PLoS One 2019; 14:e0223254. [PMID: 31714914 PMCID: PMC6850524 DOI: 10.1371/journal.pone.0223254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/17/2019] [Indexed: 01/20/2023] Open
Abstract
Down syndrome (DS) is a chromosomal disorder caused by trisomy of chromosome 21 (Ts21). Unbalanced karyotypes can lead to dysfunction of the proteostasis network (PN) and disrupted proteostasis is mechanistically associated with multiple DS comorbidities. Autophagy is a critical component of the PN that has not previously been investigated in DS. Based on our previous observations of PN disruption in DS, we investigated possible dysfunction of the autophagic machinery in human DS fibroblasts and other DS cell models. Following induction of autophagy by serum starvation, DS fibroblasts displayed impaired autophagic flux indicated by autophagolysosome accumulation and elevated p62, NBR1, and LC3-II abundance, compared to age- and sex-matched, euploid (CTL) fibroblasts. While lysosomal physiology was unaffected in both groups after serum starvation, we observed decreased basal abundance of the Soluble N-ethylmaleimide-sensitive-factor Attachment protein Receptor (SNARE) family members syntaxin 17 (STX17) and Vesicle Associated Membrane Protein 8 (VAMP8) indicating that decreased autophagic flux in DS is due at least in part to a possible impairment of autophagosome-lysosome fusion. This conclusion was further supported by the observation that over-expression of either STX17 or VAMP8 in DS fibroblasts restored autophagic degradation and reversed p62 accumulation. Collectively, our results indicate that impaired autophagic clearance is a characteristic of DS cells that can be reversed by enhancement of SNARE protein expression and provides further evidence that PN disruption represents a candidate mechanism for multiple aspects of pathogenesis in DS and a possible future target for therapeutic intervention.
Collapse
Affiliation(s)
- Stefanos Aivazidis
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Abhilasha Jain
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Abhishek K. Rauniyar
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Colin C. Anderson
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - John O. Marentette
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - David J. Orlicky
- Department of Pathology, University of Colorado School of Medicine, Aurora, CO, United States of America
| | - Kristofer S. Fritz
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Peter S. Harris
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - David Siegel
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Kenneth N. Maclean
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States of America
- The Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO, United States of America
| | - James R. Roede
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
- The Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO, United States of America
- * E-mail:
| |
Collapse
|
11
|
Peilin W, Songsong T, Chengyu Z, Zhi C, Chunhui M, Yinxian Y, Lei Z, Min M, Zongyi W, Mengkai Y, Jing X, Tao Z, Zhuoying W, Fei Y, Chengqing Y. Directed elimination of senescent cells attenuates development of osteoarthritis by inhibition of c-IAP and XIAP. Biochim Biophys Acta Mol Basis Dis 2019; 1865:2618-2632. [PMID: 31251987 DOI: 10.1016/j.bbadis.2019.05.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/28/2019] [Accepted: 05/27/2019] [Indexed: 01/02/2023]
Abstract
Aging drives the accumulation of senescent cells (SnCs) by secreting factors that cause the senescence-associated secretory phenotype (SASP), including stem cells in the bone marrow, which contribute to aging-related bone degradation. Osteoarthritis (OA) is a serious chronic injury disease, and increasing age is a major risk factor. The accumulation of SnCs may accelerate the development of OA, and the accumulation of SnCs may benefit from its resistance to apoptotic stimuli. Therefore, local elimination of SnCs could be a promising treatment for OA. Apoptosis inhibitor protein (IAP) is an important antiapoptotic protein in vivo. AT-406 is a small molecule inhibitor of the IAP genes and also regulates the transcription of several genes. Here, we show that SnCs upregulate the antiapoptotic proteins c-IAP1, c-IAP2 and XIAP.The combined inhibition of c-IAP1, c-IAP2 and XIAP using siRNA or AT-406 specifically induce the apoptosis of SnCs.In addition, XIAP and STX17 bind to each other to regulate the fusion of autophagosomes and lysosomes in SnCs, which in turn, affects the fate of SnCs. It is worth noting that the clearance of SnCs attenuated the secretion of SASP and created a proregenerative environment. Most importantly, local clearance of SnCs significantly attenuated the progression of osteoarthritis in rats without significant toxic effects. Thus, local elimination of SnCs may be a potential treatment for OA. This is the first report of inhibition of IAPs for clearing SnCs and suggests that eradication of SnCs may be a new strategy for the treatment of age-related diseases.
Collapse
Affiliation(s)
- Wang Peilin
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China
| | - Teng Songsong
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhuang Chengyu
- Department of Orthopaedics, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Cui Zhi
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China
| | - Ma Chunhui
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yu Yinxian
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhou Lei
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China
| | - Mao Min
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China
| | - Wang Zongyi
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China.
| | - Yang Mengkai
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China
| | - Xu Jing
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China
| | - Zhang Tao
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China.
| | - Wang Zhuoying
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China
| | - Yin Fei
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Bone Tumor Institute, Shanghai, China
| | - Yi Chengqing
- Department of Orthopaedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| |
Collapse
|
12
|
Vats S, Manjithaya R. A reversible autophagy inhibitor blocks autophagosome-lysosome fusion by preventing Stx17 loading onto autophagosomes. Mol Biol Cell 2019; 30:2283-2295. [PMID: 31188703 PMCID: PMC6743457 DOI: 10.1091/mbc.e18-08-0482] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Autophagy is an evolutionarily conserved intracellular lysosomal degradation pathway. It is a multistep process involving de novo formation of double membrane autophagosomes that capture cytosolic constituents (cargo) and eventually fuse with lysosomes wherein the cargo gets degraded and resulting simpler biomolecules get recycled. In addition to their autophagy function, several of the autophagy-related proteins work at the interface of other vesicular trafficking pathways. Hence, development of specific autophagy modulators that do not perturb general endo-lysosomal traffic possesses unique challenges. In this article, we report a novel small molecule EACC that inhibits autophagic flux by blocking autophagosome–lysosome fusion. Strikingly, unlike other late stage inhibitors, EACC does not have any effect on lysosomal properties or on endocytosis-mediated degradation of EGF receptor. EACC affects the translocation of SNAREs Stx17 and SNAP29 on autophagosomes without impeding the completion of autophagosomes. EACC treatment also reduces the interaction of Stx17 with the HOPS subunit VPS33A and the cognate lysosomal R-SNARE VAMP8. Interestingly, this effect of EACC although quite robust is reversible and hence EACC can be used as a tool to study autophagosomal SNARE trafficking. Our results put forward a novel method to block autophagic flux by impeding the action of the autophagosomal SNAREs.
Collapse
Affiliation(s)
- Somya Vats
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| | - Ravi Manjithaya
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore-560064, India
| |
Collapse
|
13
|
Texada MJ, Malita A, Christensen CF, Dall KB, Faergeman NJ, Nagy S, Halberg KA, Rewitz K. Autophagy-Mediated Cholesterol Trafficking Controls Steroid Production. Dev Cell 2019; 48:659-671.e4. [PMID: 30799225 DOI: 10.1016/j.devcel.2019.01.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 12/05/2018] [Accepted: 01/02/2019] [Indexed: 12/14/2022]
Abstract
Steroid hormones are important signaling molecules that regulate growth and drive the development of many cancers. These factors act as long-range signals that systemically regulate the growth of the entire organism, whereas the Hippo/Warts tumor-suppressor pathway acts locally to limit organ growth. We show here that autophagy, a pathway that mediates the degradation of cellular components, also controls steroid production. This process is regulated by Warts (in mammals, LATS1/2) signaling, via its effector microRNA bantam, in response to nutrients. Specifically, autophagy-mediated mobilization and trafficking of the steroid precursor cholesterol from intracellular stores controls the production of the Drosophila steroid ecdysone. Furthermore, we also show that bantam regulates this process via the ecdysone receptor and Tor signaling, identifying pathways through which bantam regulates autophagy and growth. The Warts pathway thus promotes nutrient-dependent systemic growth during development by autophagy-dependent steroid hormone regulation (ASHR). These findings uncover an autophagic trafficking mechanism that regulates steroid production.
Collapse
Affiliation(s)
- Michael J Texada
- Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Alina Malita
- Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | | | - Kathrine B Dall
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Nils J Faergeman
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Stanislav Nagy
- Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Kenneth A Halberg
- Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Kim Rewitz
- Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark.
| |
Collapse
|
14
|
Dingjan I, Linders PTA, Verboogen DRJ, Revelo NH, Ter Beest M, van den Bogaart G. Endosomal and Phagosomal SNAREs. Physiol Rev 2018; 98:1465-1492. [PMID: 29790818 DOI: 10.1152/physrev.00037.2017] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein family is of vital importance for organelle communication. The complexing of cognate SNARE members present in both the donor and target organellar membranes drives the membrane fusion required for intracellular transport. In the endocytic route, SNARE proteins mediate trafficking between endosomes and phagosomes with other endosomes, lysosomes, the Golgi apparatus, the plasma membrane, and the endoplasmic reticulum. The goal of this review is to provide an overview of the SNAREs involved in endosomal and phagosomal trafficking. Of the 38 SNAREs present in humans, 30 have been identified at endosomes and/or phagosomes. Many of these SNAREs are targeted by viruses and intracellular pathogens, which thereby reroute intracellular transport for gaining access to nutrients, preventing their degradation, and avoiding their detection by the immune system. A fascinating picture is emerging of a complex transport network with multiple SNAREs being involved in consecutive trafficking routes.
Collapse
Affiliation(s)
- Ilse Dingjan
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Peter T A Linders
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Danielle R J Verboogen
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Natalia H Revelo
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Martin Ter Beest
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Geert van den Bogaart
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| |
Collapse
|
15
|
Abstract
Formation of the autolysosome involves SNARE-mediated autophagosome-lysosome fusion, which is mediated by a combination of the Qa SNARE STX17 (syntaxin 17), the Qbc SNARE SNAP29 and the R-SNAREs VAMP7/8. 2 very recent reports have now implicated another R-SNARE with a longin domain, YKT6, in this fusion process. Interestingly, these reports painted two different pictures of YKT6's involvement. Studies in HeLa cells indicated that YKT6, acting independently of STX17, could form a separate SNARE complex with SNAP29 and another Qa SNARE to mediate autophagosome-lysosome fusion. Conversely, work in Drosophila larvae fat cells showed that while Ykt6 could form a SNARE complex with Snap29 and Syx17/Stx17, it is readily outcompeted by lysosomal Vamp7 in this regard. Moreover, its activity in autophagosome-lysosome fusion is not impaired by mutation of the supposedly critical ionic zero-layer residue from R to Q. In this regard, YKT6 may therefore act in a noncanonical way to regulate fusion. Here, we ponder on the fresh mechanistic perspectives on the final membrane fusion step of macroautophagy/autophagy offered by these new findings. Further, we propose another possible mechanism as to how YKT6 might act, which may provide some reconciliation to the differences observed. Abbreviations: LD: longin domain.
Collapse
Affiliation(s)
- Cheryl Qian Ying Yong
- a Department of Biochemistry, Yong Loo Lin School of Medicine , National University of Singapore , Singapore
| | - Bor Luen Tang
- a Department of Biochemistry, Yong Loo Lin School of Medicine , National University of Singapore , Singapore.,b NUS Graduate School for Integrative Sciences and Engineering , National University of Singapore , Singapore
| |
Collapse
|
16
|
Zhou F, Yang X, Zhao H, Liu Y, Feng Y, An R, Lv X, Li J, Chen B. Down-regulation of OGT promotes cisplatin resistance by inducing autophagy in ovarian cancer. Am J Cancer Res 2018; 8:5200-5212. [PMID: 30555541 PMCID: PMC6276088 DOI: 10.7150/thno.27806] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/03/2018] [Indexed: 12/18/2022] Open
Abstract
Cisplatin resistance significantly affects the survival rate of patients with ovarian cancer. However, the main mechanism underlying cisplatin resistance in ovarian cancer remains unclear. Methods: Immunohistochemistry was used to determine the expression of OGT, OGA and O-GlcNAc in chemoresistant and chemosensitive ovarian cancer tissues. Functional analyses (in vitro and in vivo) were performed to confirm the role of OGT in cisplatin resistance. Autophagy-related proteins were tested by western blot. Transmission electron microscopy and mRFP-GFP-LC3 adenovirus reporter were used for autophagy flux analysis. Immunoprecipitation assay was utilized to detect protein-protein interactions. Results: We found that O-GlcNAc and O-GlcNAc transferase (OGT) levels were significantly lower in chemoresistant ovarian cancer tissues than in chemosensitive tissues, whereas O-GlcNAcase (OGA) levels did not differ. The down-regulation of OGT increased cisplatin resistance in ovarian cancer cells but had no effect on the efficacy of paclitaxel. The down-regulation of OGT improved tumor resistance to cisplatin in a mouse xenograft tumor model. OGT knockdown enhanced cisplatin-induced autophagy, which reduced apoptotic cell death induced by cisplatin, and promoted autolysosome formation. A reduction in O-GlcNAcylated SNAP-29 levels caused by the down-regulation of OGT promoted the formation of the SNARE complex and autophagic flux. Conclusion: Our findings suggest that down-regulation of OGT enhances cisplatin-induced autophagy via SNAP-29, resulting in cisplatin-resistant ovarian cancer. OGT may represent a novel target for overcoming cisplatin resistance in ovarian cancer.
Collapse
|
17
|
Danieli A, Martens S. p62-mediated phase separation at the intersection of the ubiquitin-proteasome system and autophagy. J Cell Sci 2018; 131:131/19/jcs214304. [PMID: 30287680 DOI: 10.1242/jcs.214304] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The degradation of misfolded proteins is essential for cellular homeostasis. Misfolded proteins are normally degraded by the ubiquitin-proteasome system (UPS), and selective autophagy serves as a backup mechanism when the UPS is overloaded. Selective autophagy mediates the degradation of harmful material by its sequestration within double-membrane organelles called autophagosomes. The selectivity of autophagic processes is mediated by cargo receptors, which link the cargo to the autophagosomal membrane. The p62 cargo receptor (SQSTM1) has a main function during the degradation of misfolded, ubiquitylated proteins by selective autophagy; here it functions to phase separate these proteins into larger condensates and tether them to the autophagosomal membrane. Recent work has given us crucial insights into the mechanism of action of the p62 cargo receptor during selective autophagy and how its activity can be integrated with the UPS. We will discuss these recent insights in the context of protein quality control and the emerging concept of cellular organization mediated by phase transitions.
Collapse
Affiliation(s)
- Alberto Danieli
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna BioCenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Sascha Martens
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna BioCenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| |
Collapse
|
18
|
A novel autophagy inhibitor berbamine blocks SNARE-mediated autophagosome-lysosome fusion through upregulation of BNIP3. Cell Death Dis 2018; 9:243. [PMID: 29445175 PMCID: PMC5833711 DOI: 10.1038/s41419-018-0276-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 12/07/2017] [Accepted: 12/27/2017] [Indexed: 11/08/2022]
Abstract
Increasing evidences reveal that autophagy inhibitor could enhance the effect of chemotherapy to cancer. However, few autophagy inhibitors are currently approved for clinical application in humans. Berbamine (BBM) is a natural compound extracted from traditional Chinese medicine that is widely used for treatment of a variety of diseases without any obvious side effects. Here we found that BBM is a novel auophagy inhibitor, which potently induced the accumulation of autophagosomes by inhibiting autophagosome-lysosome fusion in human breast cancer cells. Mechanistically, we found that BBM blocked autophagosome-lysosome fusion by inhibiting the interaction of SNAP29 and VAMP8. Furthermore, BBM induced upregulation of BNIP3 and the interaction between SNAP29 and BNIP3. BNIP3 depletion or SNAP29 overexpression abrogated BBM-mediated blockade of autophagosome-lysosome fusion through the interaction between SNAP29 and VAMP8, whereas BNIP3 overexpression blocked autophagosome-lysosome fusion through inhibition of the interaction between SNAP29 and VAMP8. These findings suggest that upregulation of BNIP3 and interaction between BNIP3 and SNAP29 could be involved in BBM-mediated blockade of autophagosome-lysosome fusion through inhibition of the interaction between SNAP29 and VAMP8. Our findings identify the critical role of BNIP3 in blockade of autophagosome-lysosome fusion mediated by BBM, and suggest that BBM could potentially be further developed as a novel autophagy inhibitor, which could enhance the effect of chemotherapy to cancer.
Collapse
|
19
|
Huang J, Yang Y, Fang F, Liu K. MALAT1 modulates the autophagy of retinoblastoma cell through miR‐124‐mediated stx17 regulation. J Cell Biochem 2018; 119:3853-3863. [DOI: 10.1002/jcb.26464] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/24/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Jun Huang
- Department of OrthopedicsThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Yuting Yang
- Department of OphthalmologyThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Fang Fang
- Department of OphthalmologyThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
| | - Ke Liu
- Department of OphthalmologyThe Second Xiangya HospitalCentral South UniversityChangshaHunanChina
| |
Collapse
|
20
|
Host-pathogen interactions and subversion of autophagy. Essays Biochem 2017; 61:687-697. [PMID: 29233878 PMCID: PMC5869863 DOI: 10.1042/ebc20170058] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/26/2017] [Accepted: 11/01/2017] [Indexed: 12/17/2022]
Abstract
Macroautophagy (‘autophagy’), is the process by which cells can form a double-membraned vesicle that encapsulates material to be degraded by the lysosome. This can include complex structures such as damaged mitochondria, peroxisomes, protein aggregates and large swathes of cytoplasm that can not be processed efficiently by other means of degradation. Recycling of amino acids and lipids through autophagy allows the cell to form intracellular pools that aid survival during periods of stress, including growth factor deprivation, amino acid starvation or a depleted oxygen supply. One of the major functions of autophagy that has emerged over the last decade is its importance as a safeguard against infection. The ability of autophagy to selectively target intracellular pathogens for destruction is now regarded as a key aspect of the innate immune response. However, pathogens have evolved mechanisms to either evade or reconfigure the autophagy pathway for their own survival. Understanding how pathogens interact with and manipulate the host autophagy pathway will hopefully provide a basis for combating infection and increase our understanding of the role and regulation of autophagy. Herein, we will discuss how the host cell can identify and target invading pathogens and how pathogens have adapted in order to evade destruction by the host cell. In particular, we will focus on interactions between the mammalian autophagy gene 8 (ATG8) proteins and the host and pathogen effector proteins.
Collapse
|
21
|
Neisch AL, Neufeld TP, Hays TS. A STRIPAK complex mediates axonal transport of autophagosomes and dense core vesicles through PP2A regulation. J Cell Biol 2017; 216:441-461. [PMID: 28100687 PMCID: PMC5294782 DOI: 10.1083/jcb.201606082] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/09/2016] [Accepted: 12/27/2016] [Indexed: 02/06/2023] Open
Abstract
Autophagy plays an essential role in the cellular homeostasis of neurons, facilitating the clearance of cellular debris. This clearance process is orchestrated through the assembly, transport, and fusion of autophagosomes with lysosomes for degradation. The motor protein dynein drives autophagosome motility from distal sites of assembly to sites of lysosomal fusion. In this study, we identify the scaffold protein CKA (connector of kinase to AP-1) as essential for autophagosome transport in neurons. Together with other core components of the striatin-interacting phosphatase and kinase (STRIPAK) complex, we show that CKA associates with dynein and directly binds Atg8a, an autophagosomal protein. CKA is a regulatory subunit of PP2A, a component of the STRIPAK complex. We propose that the STRIPAK complex modulates dynein activity. Consistent with this hypothesis, we provide evidence that CKA facilitates axonal transport of dense core vesicles and autophagosomes in a PP2A-dependent fashion. In addition, CKA-deficient flies exhibit PP2A-dependent motor coordination defects. CKA function within the STRIPAK complex is crucial to prevent transport defects that may contribute to neurodegeneration.
Collapse
Affiliation(s)
- Amanda L Neisch
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Thomas P Neufeld
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Thomas S Hays
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| |
Collapse
|
22
|
Assessing Basal and Acute Autophagic Responses in the Adult Drosophila Nervous System: The Impact of Gender, Genetics and Diet on Endogenous Pathway Profiles. PLoS One 2016; 11:e0164239. [PMID: 27711219 PMCID: PMC5053599 DOI: 10.1371/journal.pone.0164239] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/21/2016] [Indexed: 11/28/2022] Open
Abstract
The autophagy pathway is critical for the long-term homeostasis of cells and adult organisms and is often activated during periods of stress. Reduced pathway efficacy plays a central role in several progressive neurological disorders that are associated with the accumulation of cytotoxic peptides and protein aggregates. Previous studies have shown that genetic and transgenic alterations to the autophagy pathway impacts longevity and neural aggregate profiles of adult Drosophila. In this study, we have identified methods to measure the acute in vivo induction of the autophagy pathway in the adult fly CNS. Our findings indicate that the genotype, age, and gender of adult flies can influence pathway responses. Further, we demonstrate that middle-aged male flies exposed to intermittent fasting (IF) had improved neuronal autophagic profiles. IF-treated flies also had lower neural aggregate profiles, maintained more youthful behaviors and longer lifespans, when compared to ad libitum controls. In summary, we present methodology to detect dynamic in vivo changes that occur to the autophagic profiles in the adult Drosophila CNS and that a novel IF-treatment protocol improves pathway response in the aging nervous system.
Collapse
|
23
|
Takáts S, Varga Á, Pircs K, Juhász G. Loss of Drosophila Vps16A enhances autophagosome formation through reduced Tor activity. Autophagy 2016; 11:1209-15. [PMID: 26061715 PMCID: PMC4590676 DOI: 10.1080/15548627.2015.1059559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The HOPS tethering complex facilitates autophagosome-lysosome fusion by binding to Syx17 (Syntaxin 17), the autophagosomal SNARE. Here we show that loss of the core HOPS complex subunit Vps16A enhances autophagosome formation and slows down Drosophila development. Mechanistically, Tor kinase is less active in Vps16A mutants likely due to impaired endocytic and biosynthetic transport to the lysosome, a site of its activation. Tor reactivation by overexpression of Rheb suppresses autophagosome formation and restores growth and developmental timing in these animals. Thus, Vps16A reduces autophagosome numbers both by indirectly restricting their formation rate and by directly promoting their clearance. In contrast, the loss of Syx17 blocks autophagic flux without affecting the induction step in Drosophila.
Collapse
Affiliation(s)
- Szabolcs Takáts
- a Department of Anatomy ; Cell and Developmental Biology; Eötvös Lorand University ; Budapest , Hungary
| | | | | | | |
Collapse
|
24
|
Xia D, Qu L, Li G, Hongdu B, Xu C, Lin X, Lou Y, He Q, Ma D, Chen Y. MARCH2 regulates autophagy by promoting CFTR ubiquitination and degradation and PIK3CA-AKT-MTOR signaling. Autophagy 2016; 12:1614-30. [PMID: 27308891 DOI: 10.1080/15548627.2016.1192752] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
MARCH2 (membrane-associated RING-CH protein 2), an E3 ubiquitin ligase, is mainly associated with the vesicle trafficking. In the present study, for the first time, we demonstrated that MARCH2 negatively regulates autophagy. Our data indicated that overexpression of MARCH2 impaired autophagy, as evidenced by attenuated levels of LC3B-II and impaired degradation of endogenous and exogenous autophagic substrates. By contrast, loss of MARCH2 expression had the opposite effects. In vivo experiments demonstrate that MARCH2 knockout mediated autophagy results in an inhibition of tumorigenicity. Further investigation revealed that the induction of autophagy by MARCH2 deficiency was mediated through the PIK3CA-AKT-MTOR signaling pathway. Additionally, we found that MARCH2 interacts with CFTR (cystic fibrosis transmembrane conductance regulator), promotes the ubiquitination and degradation of CFTR, and inhibits CFTR-mediated autophagy in tumor cells. The functional PDZ domain of MARCH2 is required for the association with CFTR. Thus, our study identified a novel negative regulator of autophagy and suggested that the physical and functional connection between the MARCH2 and CFTR in different conditions will be elucidated in the further experiments.
Collapse
Affiliation(s)
- Dan Xia
- a Department of Immunology , Peking University School of Basic Medical Sciences , Beijing , China.,b Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center , Beijing , China.,c Center for Human Disease Genomics, Peking University , Beijing , China
| | - Liujing Qu
- a Department of Immunology , Peking University School of Basic Medical Sciences , Beijing , China.,b Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center , Beijing , China.,c Center for Human Disease Genomics, Peking University , Beijing , China
| | - Ge Li
- a Department of Immunology , Peking University School of Basic Medical Sciences , Beijing , China.,b Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center , Beijing , China.,c Center for Human Disease Genomics, Peking University , Beijing , China
| | - Beiqi Hongdu
- a Department of Immunology , Peking University School of Basic Medical Sciences , Beijing , China.,b Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center , Beijing , China.,c Center for Human Disease Genomics, Peking University , Beijing , China
| | - Chentong Xu
- a Department of Immunology , Peking University School of Basic Medical Sciences , Beijing , China.,b Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center , Beijing , China.,c Center for Human Disease Genomics, Peking University , Beijing , China
| | - Xin Lin
- a Department of Immunology , Peking University School of Basic Medical Sciences , Beijing , China.,b Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center , Beijing , China.,c Center for Human Disease Genomics, Peking University , Beijing , China
| | - Yaxin Lou
- d Medical and Healthy Analytical Center, Peking University , Beijing , China
| | - Qihua He
- d Medical and Healthy Analytical Center, Peking University , Beijing , China
| | - Dalong Ma
- a Department of Immunology , Peking University School of Basic Medical Sciences , Beijing , China.,b Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center , Beijing , China.,c Center for Human Disease Genomics, Peking University , Beijing , China
| | - Yingyu Chen
- a Department of Immunology , Peking University School of Basic Medical Sciences , Beijing , China.,b Key Laboratory of Medical Immunology, Ministry of Health, Peking University Health Sciences Center , Beijing , China.,c Center for Human Disease Genomics, Peking University , Beijing , China
| |
Collapse
|
25
|
Wu TT, Li WM, Yao YM. Interactions between Autophagy and Inhibitory Cytokines. Int J Biol Sci 2016; 12:884-97. [PMID: 27313501 PMCID: PMC4910606 DOI: 10.7150/ijbs.15194] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/12/2016] [Indexed: 02/06/2023] Open
Abstract
Autophagy is a degradative pathway that plays an essential role in maintaining cellular homeostasis. Most early studies of autophagy focused on its involvement in age-associated degeneration and nutrient deprivation. However, the immunological functions of autophagy have become more widely studied in recent years. Autophagy has been shown to be an intrinsic cellular defense mechanism in the innate and adaptive immune responses. Cytokines belong to a broad and loose category of proteins and are crucial for innate and adaptive immunity. Inhibitory cytokines have evolved to permit tolerance to self while also contributing to the eradication of invading pathogens. Interactions between inhibitory cytokines and autophagy have recently been reported, revealing a novel mechanism by which autophagy controls the immune response. In this review, we discuss interactions between autophagy and the regulatory cytokines IL-10, transforming growth factor-β, and IL-27. We also mention possible interactions between two newly discovered cytokines, IL-35 and IL-37, and autophagy.
Collapse
Affiliation(s)
- Tian-Tian Wu
- 1. Department of Hepatobiliary Surgery, the 309th Hospital of Chinese PLA, Beijing 100091, People's Republic of China
| | - Wei-Min Li
- 1. Department of Hepatobiliary Surgery, the 309th Hospital of Chinese PLA, Beijing 100091, People's Republic of China
| | - Yong-Ming Yao
- 2. Trauma Research Center, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing 100048, People's Republic of China; 3. State Key Laboratory of Kidney Disease, the Chinese PLA General Hospital, Beijing 100853, People's Republic of China
| |
Collapse
|
26
|
Shaikh S, Troncoso R, Criollo A, Bravo-Sagua R, García L, Morselli E, Cifuentes M, Quest AFG, Hill JA, Lavandero S. Regulation of cardiomyocyte autophagy by calcium. Am J Physiol Endocrinol Metab 2016; 310:E587-E596. [PMID: 26884385 PMCID: PMC4835942 DOI: 10.1152/ajpendo.00374.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 02/10/2016] [Indexed: 11/22/2022]
Abstract
Calcium signaling plays a crucial role in a multitude of events within the cardiomyocyte, including cell cycle control, growth, apoptosis, and autophagy. With respect to calcium-dependent regulation of autophagy, ion channels and exchangers, receptors, and intracellular mediators play fundamental roles. In this review, we discuss calcium-dependent regulation of cardiomyocyte autophagy, a lysosomal mechanism that is often cytoprotective, serving to defend against disease-related stress and nutrient insufficiency. We also highlight the importance of the subcellular distribution of calcium and related proteins, interorganelle communication, and other key signaling events that govern cardiomyocyte autophagy.
Collapse
Affiliation(s)
- Soni Shaikh
- Advanced Center for Chronic Disease and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Rodrigo Troncoso
- Advanced Center for Chronic Disease and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Alfredo Criollo
- Advanced Center for Chronic Disease and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
| | - Roberto Bravo-Sagua
- Advanced Center for Chronic Disease and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Lorena García
- Advanced Center for Chronic Disease and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Santiago, Chile
| | - Eugenia Morselli
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mariana Cifuentes
- Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Andrew F G Quest
- Advanced Center for Chronic Disease and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile; and
| | - Joseph A Hill
- Departments of Internal Medicine (Cardiology Division) and
- Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sergio Lavandero
- Advanced Center for Chronic Disease and Center for Molecular Studies of the Cell, Facultad de Ciencias Quimicas y Farmaceuticas and Facultad de Medicina, Universidad de Chile, Santiago, Chile;
- Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Santiago, Chile
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile; and
- Departments of Internal Medicine (Cardiology Division) and
| |
Collapse
|
27
|
Rey-Jurado E, Riedel CA, González PA, Bueno SM, Kalergis AM. Contribution of autophagy to antiviral immunity. FEBS Lett 2015; 589:3461-70. [PMID: 26297829 PMCID: PMC7094639 DOI: 10.1016/j.febslet.2015.07.047] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 07/20/2015] [Accepted: 07/29/2015] [Indexed: 12/22/2022]
Abstract
Although identified in the 1960's, interest in autophagy has significantly increased in the past decade with notable research efforts oriented at understanding as to how this multi-protein complex operates and is regulated. Autophagy is commonly defined as a "self-eating" process evolved by eukaryotic cells to recycle senescent organelles and expired proteins, which is significantly increased during cellular stress responses. In addition, autophagy can also play important roles during human diseases, such as cancer, neurodegenerative and autoimmune disorders. Furthermore, novel findings suggest that autophagy contributes to the host defense against microbial infections. In this article, we review the role of macroautophagy in antiviral immune responses and discuss molecular mechanisms evolved by viral pathogens to evade this process. A role for autophagy as an effector mechanism used both, by innate and adaptive immunity is also discussed.
Collapse
Affiliation(s)
- Emma Rey-Jurado
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia A Riedel
- Millennium Institute on Immunology and Immunotherapy, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas y Facultad de Medicina, Universidad Andrés Bello, Santiago, Chile
| | - Pablo A González
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M Bueno
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Departamento de Inmunología Clínica y Reumatología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile; INSERM U1064, Nantes, France.
| |
Collapse
|
28
|
Zhu Q, Yamakuchi M, Lowenstein CJ. SNAP23 Regulates Endothelial Exocytosis of von Willebrand Factor. PLoS One 2015; 10:e0118737. [PMID: 26266817 PMCID: PMC4534191 DOI: 10.1371/journal.pone.0118737] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 07/22/2015] [Indexed: 11/18/2022] Open
Abstract
Endothelial exocytosis regulates vascular thrombosis and inflammation. The trafficking and release of endothelial vesicles is mediated by SNARE (Soluble NSF Attachment protein REceptors) molecules, but the exact identity of endothelial SNAREs has been unclear. Three SNARE molecules form a ternary complex, including isoforms of the syntaxin (STX), vesicle-associated membrane protein (VAMP), and synaptosomal-associated protein (SNAP) families. We now identify SNAP23 as the predominant endothelial SNAP isoform that mediates endothelial exocytosis of von Willebrand Factor (VWF). SNAP23 was localized to the plasma membrane. Knockdown of SNAP23 decreased endothelial exocytosis, suggesting it is important for endothelial exocytosis. SNAP23 interacted with the endothelial exocytic machinery, and formed complexes with other known endothelial SNARE molecules. Taken together, these data suggest that SNAP23 is a key component of the endothelial SNARE machinery that mediates endothelial exocytosis.
Collapse
Affiliation(s)
- Qiuyu Zhu
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Munekazu Yamakuchi
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Charles J. Lowenstein
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
- * E-mail:
| |
Collapse
|
29
|
Ploen D, Hildt E. Hepatitis C virus comes for dinner: How the hepatitis C virus interferes with autophagy. World J Gastroenterol 2015; 21:8492-8507. [PMID: 26229393 PMCID: PMC4515832 DOI: 10.3748/wjg.v21.i28.8492] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 05/10/2015] [Accepted: 06/16/2015] [Indexed: 02/06/2023] Open
Abstract
Autophagy is a highly-regulated, conserved cellular process for the degradation of intracellular components in lysosomes to maintain the energetic balance of the cell. It is a pro-survival mechanism that plays an important role during development, differentiation, apoptosis, ageing and innate and adaptive immune response. Besides, autophagy has been described to be involved in the development of various human diseases, e.g., chronic liver diseases and the development of hepatocellular carcinoma. The hepatitis C virus (HCV) is a major cause of chronic liver diseases. It has recently been described that HCV, like other RNA viruses, hijacks the autophagic machinery to improve its replication. However, the mechanisms underlying its activation are conflicting. HCV replication and assembly occurs at the so-called membranous web that consists of lipid droplets and rearranged endoplasmic reticulum-derived membranes including single-, double- and multi-membrane vesicles. The double-membrane vesicles have been identified to contain NS3, NS5A, viral RNA and the autophagosomal marker microtubule-associated protein 1 light chain 3, corroborating the involvement of the autophagic pathway in the HCV life-cycle. In this review, we will highlight the crosstalk of the autophagosomal compartment with different steps of the HCV life-cycle and address its implications on favoring the survival of infected hepatocytes.
Collapse
|
30
|
Lőrincz P, Takáts S, Kárpáti M, Juhász G. iFly: The eye of the fruit fly as a model to study autophagy and related trafficking pathways. Exp Eye Res 2015; 144:90-8. [PMID: 26091788 DOI: 10.1016/j.exer.2015.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 05/28/2015] [Accepted: 06/15/2015] [Indexed: 12/21/2022]
Abstract
Autophagy is a process by which eukaryotic cells degrade and recycle their intracellular components within lysosomes. Autophagy is induced by starvation to ensure survival of individual cells, and it has evolved to fulfill numerous additional roles in animals. Autophagy not only provides nutrient supply through breakdown products during starvation, but it is also required for the elimination of damaged or surplus organelles, toxic proteins, aggregates, and pathogens, and is essential for normal organelle turnover. Because of these roles, defects in autophagy have pathological consequences. Here we summarize the current knowledge of autophagy and related trafficking pathways in a convenient model: the compound eye of the fruit fly Drosophila melanogaster. In our review, we present a general introduction of the development and structure of the compound eye. This is followed by a discussion of various neurodegeneration models including retinopathies, with special emphasis on the protective role of autophagy against these diseases.
Collapse
Affiliation(s)
- Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary
| | - Szabolcs Takáts
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary
| | - Manuéla Kárpáti
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány s. 1/C, Budapest H-1117, Hungary; Momentum Drosophila Autophagy Research Group, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, Szeged H-6726, Hungary.
| |
Collapse
|
31
|
Tian X, Gala U, Zhang Y, Shang W, Nagarkar Jaiswal S, di Ronza A, Jaiswal M, Yamamoto S, Sandoval H, Duraine L, Sardiello M, Sillitoe RV, Venkatachalam K, Fan H, Bellen HJ, Tong C. A voltage-gated calcium channel regulates lysosomal fusion with endosomes and autophagosomes and is required for neuronal homeostasis. PLoS Biol 2015; 13:e1002103. [PMID: 25811491 PMCID: PMC4374850 DOI: 10.1371/journal.pbio.1002103] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 02/11/2015] [Indexed: 01/03/2023] Open
Abstract
Autophagy helps deliver sequestered intracellular cargo to lysosomes for proteolytic degradation and thereby maintains cellular homeostasis by preventing accumulation of toxic substances in cells. In a forward mosaic screen in Drosophila designed to identify genes required for neuronal function and maintenance, we identified multiple cacophony (cac) mutant alleles. They exhibit an age-dependent accumulation of autophagic vacuoles (AVs) in photoreceptor terminals and eventually a degeneration of the terminals and surrounding glia. cac encodes an α1 subunit of a Drosophila voltage-gated calcium channel (VGCC) that is required for synaptic vesicle fusion with the plasma membrane and neurotransmitter release. Here, we show that cac mutant photoreceptor terminals accumulate AV-lysosomal fusion intermediates, suggesting that Cac is necessary for the fusion of AVs with lysosomes, a poorly defined process. Loss of another subunit of the VGCC, α2δ or straightjacket (stj), causes phenotypes very similar to those caused by the loss of cac, indicating that the VGCC is required for AV-lysosomal fusion. The role of VGCC in AV-lysosomal fusion is evolutionarily conserved, as the loss of the mouse homologues, Cacna1a and Cacna2d2, also leads to autophagic defects in mice. Moreover, we find that CACNA1A is localized to the lysosomes and that loss of lysosomal Cacna1a in cerebellar cultured neurons leads to a failure of lysosomes to fuse with endosomes and autophagosomes. Finally, we show that the lysosomal CACNA1A but not the plasma-membrane resident CACNA1A is required for lysosomal fusion. In summary, we present a model in which the VGCC plays a role in autophagy by regulating the fusion of AVs with lysosomes through its calcium channel activity and hence functions in maintaining neuronal homeostasis. A voltage-gated calcium channel required for neurotransmitter release also regulates the fusion of neuronal lysosomes with endosomes and autophagosomes, thereby helping to maintain cellular homeostasis. Autophagy is a cellular process used by cells to prevent the accumulation of toxic substances. It delivers misfolded proteins and damaged organelles by fusing autophagosomes—organelles formed by a double membrane that surrounds the “debris” to be eliminated—with lysosomes. How this fusion process is regulated during autophagy, however, remains to be established. Here, we analyze this process in flies and mice, and find that loss of different subunits of a specific type of Voltage Gated Calcium Channel (VGCC) leads to defects in lysosomal fusion with autophagosomes in neurons. It was already known that VGCCs control calcium entry at synaptic terminals to promote the fusion of synaptic vesicles with the plasma membrane, and that mutations in the subunits of VGCCs in humans cause neurological diseases. Our data indicate that defects in autophagy and lysosomal fusion are independent of defects in synaptic vesicle fusion and neurotransmitter release, and we show that a specific VGCC is present on lysosomal membranes where it is required for lysosomal fusion with endosomes and autophagosomes. These observations suggest that the fusion events required in autophagy rely on mechanisms similar to those that trigger the fusion of synaptic vesicles with the presynaptic membrane.
Collapse
Affiliation(s)
- Xuejun Tian
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Upasana Gala
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yongping Zhang
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Weina Shang
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Sonal Nagarkar Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alberto di Ronza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Marco Sardiello
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Roy V. Sillitoe
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology and Immunology, Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kartik Venkatachalam
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Integrative Biology and Pharmacology, University of Texas School of Medicine, Houston, Texas, United States of America
| | - Hengyu Fan
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (CT), (HJB)
| | - Chao Tong
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, China
- * E-mail: (CT), (HJB)
| |
Collapse
|
32
|
How and why to study autophagy in Drosophila: it's more than just a garbage chute. Methods 2014; 75:151-61. [PMID: 25481477 PMCID: PMC4358840 DOI: 10.1016/j.ymeth.2014.11.016] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/21/2014] [Accepted: 11/24/2014] [Indexed: 01/30/2023] Open
Abstract
During the catabolic process of autophagy, cytoplasmic material is transported to the lysosome for degradation and recycling. This way, autophagy contributes to the homeodynamic turnover of proteins, lipids, nucleic acids, glycogen, and even whole organelles. Autophagic activity is increased by adverse conditions such as nutrient limitation, growth factor withdrawal and oxidative stress, and it generally protects cells and organisms to promote their survival. Misregulation of autophagy is likely involved in numerous human pathologies including aging, cancer, infections and neurodegeneration, so its biomedical relevance explains the still growing interest in this field. Here we discuss the different microscopy-based, biochemical and genetic methods currently available to study autophagy in various tissues of the popular model Drosophila. We show examples for results obtained in different assays, explain how to interpret these with regard to autophagic activity, and how to find out which step of autophagy a given gene product is involved in.
Collapse
|
33
|
Lu Y, Dong S, Hao B, Li C, Zhu K, Guo W, Wang Q, Cheung KH, Wong CWM, Wu WT, Markus H, Yue J. Vacuolin-1 potently and reversibly inhibits autophagosome-lysosome fusion by activating RAB5A. Autophagy 2014; 10:1895-905. [PMID: 25483964 PMCID: PMC4502727 DOI: 10.4161/auto.32200] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Autophagy is a catabolic lysosomal degradation process essential for cellular homeostasis and cell survival. Dysfunctional autophagy has been associated with a wide range of human diseases, e.g., cancer and neurodegenerative diseases. A large number of small molecules that modulate autophagy have been widely used to dissect this process and some of them, e.g., chloroquine (CQ), might be ultimately applied to treat a variety of autophagy-associated human diseases. Here we found that vacuolin-1 potently and reversibly inhibited the fusion between autophagosomes and lysosomes in mammalian cells, thereby inducing the accumulation of autophagosomes. Interestingly, vacuolin-1 was less toxic but at least 10-fold more potent in inhibiting autophagy compared with CQ. Vacuolin-1 treatment also blocked the fusion between endosomes and lysosomes, resulting in a defect in general endosomal-lysosomal degradation. Treatment of cells with vacuolin-1 alkalinized lysosomal pH and decreased lysosomal Ca2+ content. Besides marginally inhibiting vacuolar ATPase activity, vacuolin-1 treatment markedly activated RAB5A GTPase activity. Expression of a dominant negative mutant of RAB5A or RAB5A knockdown significantly inhibited vacuolin-1-induced autophagosome-lysosome fusion blockage, whereas expression of a constitutive active form of RAB5A suppressed autophagosome-lysosome fusion. These data suggest that vacuolin-1 activates RAB5A to block autophagosome-lysosome fusion. Vacuolin-1 and its analogs present a novel class of drug that can potently and reversibly modulate autophagy.
Collapse
Key Words
- ATG, autophagy-related
- BAF, bafilomycin A1
- CQ, chloroquine
- CTSB, cathepsin B
- CTSL, cathepsin L
- EGFR, epidermal growth factor receptor
- GFP, green fluorescent protein
- GPN, glycyl-l-phenylalanine 2-naphthylamide
- LAMP1, lysosomal-associated membrane protein 1
- Leup, leupeptin
- MAP1LC3, microtubule-associated protein 1 light chain 3
- MTOR, mechanistic target of rapamycin
- RAB5A
- RFP, red fluorescent protein
- autophagosomes
- endosomes
- lysosomes
- pH
- tfLC3, tandem fluorescence-tagged LC3
- vacuolin-1
Collapse
Affiliation(s)
- Yingying Lu
- a Department of Biomedical Sciences ; City University of Hong Kong ; Hong Kong , China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Lippai M, Lőw P. The role of the selective adaptor p62 and ubiquitin-like proteins in autophagy. BIOMED RESEARCH INTERNATIONAL 2014; 2014:832704. [PMID: 25013806 PMCID: PMC4075091 DOI: 10.1155/2014/832704] [Citation(s) in RCA: 240] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/15/2014] [Accepted: 05/19/2014] [Indexed: 01/08/2023]
Abstract
The ubiquitin-proteasome system and autophagy were long viewed as independent, parallel degradation systems with no point of intersection. By now we know that these degradation pathways share certain substrates and regulatory molecules and show coordinated and compensatory function. Two ubiquitin-like protein conjugation pathways were discovered that are required for autophagosome biogenesis: the Atg12-Atg5-Atg16 and Atg8 systems. Autophagy has been considered to be essentially a nonselective process, but it turned out to be at least partially selective. Selective substrates of autophagy include damaged mitochondria, intracellular pathogens, and even a subset of cytosolic proteins with the help of ubiquitin-binding autophagic adaptors, such as p62/SQSTM1, NBR1, NDP52, and Optineurin. These proteins selectively recognize autophagic cargo and mediate its engulfment into autophagosomes by binding to the small ubiquitin-like modifiers that belong to the Atg8/LC3 family.
Collapse
Affiliation(s)
- Mónika Lippai
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány Péter sétány 1/C., Budapest 1117, Hungary
| | - Péter Lőw
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Pázmány Péter sétány 1/C., Budapest 1117, Hungary
| |
Collapse
|
35
|
Lőrincz P, Lakatos Z, Maruzs T, Szatmári Z, Kis V, Sass M. Atg6/UVRAG/Vps34-containing lipid kinase complex is required for receptor downregulation through endolysosomal degradation and epithelial polarity during Drosophila wing development. BIOMED RESEARCH INTERNATIONAL 2014; 2014:851349. [PMID: 25006588 PMCID: PMC4074780 DOI: 10.1155/2014/851349] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/01/2014] [Indexed: 11/18/2022]
Abstract
Atg6 (Beclin 1 in mammals) is a core component of the Vps34 PI3K (III) complex, which promotes multiple vesicle trafficking pathways. Atg6 and Vps34 form two distinct PI3K (III) complexes in yeast and mammalian cells, either with Atg14 or with UVRAG. The functions of these two complexes are not entirely clear, as both Atg14 and UVRAG have been suggested to regulate both endocytosis and autophagy. In this study, we performed a microscopic analysis of UVRAG, Atg14, or Atg6 loss-of-function cells in the developing Drosophila wing. Both autophagy and endocytosis are seriously impaired and defective endolysosomes accumulate upon loss of Atg6. We show that Atg6 is required for the downregulation of Notch and Wingless signaling pathways; thus it is essential for normal wing development. Moreover, the loss of Atg6 impairs cell polarity. Atg14 depletion results in autophagy defects with no effect on endocytosis or cell polarity, while the silencing of UVRAG phenocopies all but the autophagy defect of Atg6 depleted cells. Thus, our results indicate that the UVRAG-containing PI3K (III) complex is required for receptor downregulation through endolysosomal degradation and for the establishment of proper cell polarity in the developing wing, while the Atg14-containing complex is involved in autophagosome formation.
Collapse
Affiliation(s)
- Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Zsolt Lakatos
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Tamás Maruzs
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Zsuzsanna Szatmári
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Viktor Kis
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| | - Miklós Sass
- Department of Anatomy, Cell and Developmental Biology, Eotvos Lorand University, Budapest 1117, Hungary
| |
Collapse
|
36
|
Mulakkal NC, Nagy P, Takats S, Tusco R, Juhász G, Nezis IP. Autophagy in Drosophila: from historical studies to current knowledge. BIOMED RESEARCH INTERNATIONAL 2014; 2014:273473. [PMID: 24949430 PMCID: PMC4052151 DOI: 10.1155/2014/273473] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/17/2014] [Indexed: 12/17/2022]
Abstract
The discovery of evolutionarily conserved Atg genes required for autophagy in yeast truly revolutionized this research field and made it possible to carry out functional studies on model organisms. Insects including Drosophila are classical and still popular models to study autophagy, starting from the 1960s. This review aims to summarize past achievements and our current knowledge about the role and regulation of autophagy in Drosophila, with an outlook to yeast and mammals. The basic mechanisms of autophagy in fruit fly cells appear to be quite similar to other eukaryotes, and the role that this lysosomal self-degradation process plays in Drosophila models of various diseases already made it possible to recognize certain aspects of human pathologies. Future studies in this complete animal hold great promise for the better understanding of such processes and may also help finding new research avenues for the treatment of disorders with misregulated autophagy.
Collapse
Affiliation(s)
- Nitha C. Mulakkal
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Peter Nagy
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Szabolcs Takats
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Radu Tusco
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Ioannis P. Nezis
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| |
Collapse
|