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Nguyen TTA, Mohanty V, Yan Y, Francis KR, Cologna SM. Comparative Hippocampal Proteome and Phosphoproteome in a Niemann-Pick, Type C1 Mouse Model Reveal Insights into Disease Mechanisms. J Proteome Res 2024; 23:84-94. [PMID: 37999680 DOI: 10.1021/acs.jproteome.3c00375] [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] [Indexed: 11/25/2023]
Abstract
Niemann-Pick disease, type C (NPC) is a neurodegenerative, lysosomal storage disorder in individuals carrying two mutated copies of either the NPC1 or NPC2 gene. Consequently, impaired cholesterol recycling and an array of downstream events occur. Interestingly, in NPC, the hippocampus displays lysosomal lipid storage but does not succumb to progressive neurodegeneration as significantly as other brain regions. Since defining the neurodegeneration mechanisms in this disease is still an active area of research, we use mass spectrometry to analyze the overall proteome and phosphorylation pattern changes in the hippocampal region of a murine model of NPC. Using 3 week old mice representing an early disease time point, we observed changes in the expression of 47 proteins, many of which are consistent with the previous literature. New to this study, changes in members of the SNARE complex, including STX7, VTI1B, and VAMP7, were identified. Furthermore, we identified that phosphorylation of T286 on CaMKIIα and S1303 on NR2B increased in mutant animals, even at the late stage of the disease. These phosphosites are crucial to learning and memory and can trigger neuronal death by altering protein-protein interactions.
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Affiliation(s)
- Thu T A Nguyen
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Varshasnata Mohanty
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Ying Yan
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Kevin R Francis
- Cellular Therapies and Stem Cell Biology Group, Sanford Research, Sioux Falls, South Dakota 57104, United States
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota 57105, United States
| | - Stephanie M Cologna
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
- Laboratory of Integrated Neuroscience, University of Illinois Chicago, Chicago, Illinois 60607, United States
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2
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Hu Y, Wang R, Liu J, Wang Y, Dong J. Lipid droplet deposition in the regenerating liver: A promoter, inhibitor, or bystander? Hepatol Commun 2023; 7:e0267. [PMID: 37708445 PMCID: PMC10503682 DOI: 10.1097/hc9.0000000000000267] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/29/2023] [Indexed: 09/16/2023] Open
Abstract
Liver regeneration (LR) is a complex process involving intricate networks of cellular connections, cytokines, and growth factors. During the early stages of LR, hepatocytes accumulate lipids, primarily triacylglycerol, and cholesterol esters, in the lipid droplets. Although it is widely accepted that this phenomenon contributes to LR, the impact of lipid droplet deposition on LR remains a matter of debate. Some studies have suggested that lipid droplet deposition has no effect or may even be detrimental to LR. This review article focuses on transient regeneration-associated steatosis and its relationship with the liver regenerative response.
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Affiliation(s)
- Yuelei Hu
- Department of Hepatobiliary and Pancreatic Surgery, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Ruilin Wang
- Department of Cadre’s Wards Ultrasound Diagnostics. Ultrasound Diagnostic Center, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Juan Liu
- Research Unit of Precision Hepatobiliary Surgery Paradigm, Chinese Academy of Medical Sciences, Beijing, China
- Hepatopancreatobiliary Center, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
- Institute for Organ Transplant and Bionic Medicine, Tsinghua University, Beijing, China
- Clinical Translational Science Center, Beijing Tsinghua Changgung Hospital, Tsinghua University, Beijing, China
| | - Yunfang Wang
- Research Unit of Precision Hepatobiliary Surgery Paradigm, Chinese Academy of Medical Sciences, Beijing, China
- Hepatopancreatobiliary Center, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
- Institute for Organ Transplant and Bionic Medicine, Tsinghua University, Beijing, China
- Clinical Translational Science Center, Beijing Tsinghua Changgung Hospital, Tsinghua University, Beijing, China
| | - Jiahong Dong
- Department of Hepatobiliary and Pancreatic Surgery, The First Hospital of Jilin University, Jilin University, Changchun, China
- Research Unit of Precision Hepatobiliary Surgery Paradigm, Chinese Academy of Medical Sciences, Beijing, China
- Hepatopancreatobiliary Center, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
- Institute for Organ Transplant and Bionic Medicine, Tsinghua University, Beijing, China
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3
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Chiang YT, Wu YY, Lin YC, Huang YY, Lu JC. Cyclodextrin-Mediated Cholesterol Depletion Induces Adiponectin Secretion in 3T3-L1 Adipocytes. Int J Mol Sci 2023; 24:14718. [PMID: 37834165 PMCID: PMC10572842 DOI: 10.3390/ijms241914718] [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: 07/31/2023] [Revised: 09/26/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Adipocytes store a significant amount of cholesterol and triglycerides. However, whether cholesterol modulates adipocyte function remains largely unknown. We modulated the cholesterol level in adipocytes to examine its effect on the secretion of adiponectin, an important hormone specifically secreted by adipocytes. Treating differentiated 3T3-L1 adipocytes with 4 mM methyl-β-cyclodextrin (MβCD), a molecule with a high affinity for cholesterol, rapidly depleted cholesterol in adipocytes. Interestingly, MβCD treatment increased adiponectin in the medium without affecting its intracellular level, suggesting a modulation of secretion. By contrast, cholesterol addition did not affect adiponectin secretion, suggesting that cholesterol-depletion-induced intracellular cholesterol trafficking, but not reduced cholesterol level, accounted for MβCD-induced adiponectin secretion. MβCD-induced adiponectin secretion was reduced after 10 μg/mL U18666A treatment that suppressed cholesterol transport out of late endosomes/lysosomes. Depleting Niemann-Pick type C1 (NPC1) or NPC2 proteins, which mediate endosomal/lysosomal cholesterol export, consistently reduced MβCD-induced adiponectin secretion. Furthermore, treatment with 1 μM bafilomycin A1, which neutralized acidic endosomes/lysosomes, also attenuated MβCD-induced adiponectin secretion. Finally, MβCD treatment redistributed cellular adiponectin to lower-density fractions in sucrose gradient fractionation. Our results show that MβCD-mediated cholesterol depletion elevates the secretion of adiponectin, highlighting the involvement of endosomes and lysosomes in adiponectin secretion in adipocytes.
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Affiliation(s)
- Yu-Ting Chiang
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Ying-Yu Wu
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Yu-Chun Lin
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Yu-Yao Huang
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
| | - Juu-Chin Lu
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
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4
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Valencia-Olvera AC, Balu D, Faulk N, Amiridis A, Wang Y, Pham C, Avila-Munoz E, York JM, Thatcher GRJ, LaDu MJ. Inhibition of ACAT as a Therapeutic Target for Alzheimer's Disease Is Independent of ApoE4 Lipidation. Neurotherapeutics 2023; 20:1120-1137. [PMID: 37157042 PMCID: PMC10457278 DOI: 10.1007/s13311-023-01375-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2023] [Indexed: 05/10/2023] Open
Abstract
APOE4, encoding apolipoprotein E4 (apoE4), is the greatest genetic risk factor for Alzheimer's disease (AD), compared to the common APOE3. While the mechanism(s) underlying APOE4-induced AD risk remains unclear, increasing the lipidation of apoE4 is an important therapeutic target as apoE4-lipoproteins are poorly lipidated compared to apoE3-lipoproteins. ACAT (acyl-CoA: cholesterol-acyltransferase) catalyzes the formation of intracellular cholesteryl-ester droplets, reducing the intracellular free cholesterol (FC) pool. Thus, inhibiting ACAT increases the FC pool and facilitates lipid secretion to extracellular apoE-containing lipoproteins. Previous studies using commercial ACAT inhibitors, including avasimibe (AVAS), as well as ACAT-knock out (KO) mice, exhibit reduced AD-like pathology and amyloid precursor protein (APP) processing in familial AD (FAD)-transgenic (Tg) mice. However, the effects of AVAS with human apoE4 remain unknown. In vitro, AVAS induced apoE efflux at concentrations of AVAS measured in the brains of treated mice. AVAS treatment of male E4FAD-Tg mice (5xFAD+/-APOE4+/+) at 6-8 months had no effect on plasma cholesterol levels or distribution, the original mechanism for AVAS treatment of CVD. In the CNS, AVAS reduced intracellular lipid droplets, indirectly demonstrating target engagement. Surrogate efficacy was demonstrated by an increase in Morris water maze measures of memory and postsynaptic protein levels. Amyloid-beta peptide (Aβ) solubility/deposition and neuroinflammation were reduced, critical components of APOE4-modulated pathology. However, there was no increase in apoE4 levels or apoE4 lipidation, while amyloidogenic and non-amyloidogenic processing of APP were significantly reduced. This suggests that the AVAS-induced reduction in Aβ via reduced APP processing was sufficient to reduce AD pathology, as apoE4-lipoproteins remained poorly lipidated.
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Affiliation(s)
- Ana C. Valencia-Olvera
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Deebika Balu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Naomi Faulk
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | | | - Yueting Wang
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL 60612 USA
- Present Address: AbbVie Inc., 1 N. Waukegan Road, North Chicago, IL 60064 USA
| | - Christine Pham
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Eva Avila-Munoz
- Syneos Health, Av. Gustavo Baz 309, La Loma, Tlalnepantla de Baz, 54060 Mexico
| | - Jason M. York
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Gregory R. J. Thatcher
- Department of Pharmacology & Toxicology, University of Arizona, 1703 E Mabel St., Tucson, AZ 85721 USA
| | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612 USA
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5
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Wang Y, Wang S, Li L, Zou Y, Liu B, Fang X. Microfluidics‐based molecular profiling of tumor‐derived exosomes for liquid biopsy. VIEW 2023. [DOI: 10.1002/viw.20220048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Yuqing Wang
- School of Pharmacy Shanghai Stomatological Hospital Department of Chemistry Fudan University Shanghai China
| | - Shurong Wang
- School of Pharmacy Shanghai Stomatological Hospital Department of Chemistry Fudan University Shanghai China
| | - Lanting Li
- School of Pharmacy Shanghai Stomatological Hospital Department of Chemistry Fudan University Shanghai China
| | - Yan Zou
- School of Pharmacy Shanghai Stomatological Hospital Department of Chemistry Fudan University Shanghai China
| | - Baohong Liu
- School of Pharmacy Shanghai Stomatological Hospital Department of Chemistry Fudan University Shanghai China
| | - Xiaoni Fang
- School of Pharmacy Shanghai Stomatological Hospital Department of Chemistry Fudan University Shanghai China
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6
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Microglia and Cholesterol Handling: Implications for Alzheimer's Disease. Biomedicines 2022; 10:biomedicines10123105. [PMID: 36551857 PMCID: PMC9775660 DOI: 10.3390/biomedicines10123105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/04/2022] Open
Abstract
Cholesterol is essential for brain function and structure, however altered cholesterol metabolism and transport are hallmarks of multiple neurodegenerative conditions, including Alzheimer's disease (AD). The well-established link between apolipoprotein E (APOE) genotype and increased AD risk highlights the importance of cholesterol and lipid transport in AD etiology. Whereas more is known about the regulation and dysregulation of cholesterol metabolism and transport in neurons and astrocytes, less is known about how microglia, the immune cells of the brain, handle cholesterol, and the subsequent implications for the ability of microglia to perform their essential functions. Evidence is emerging that a high-cholesterol environment, particularly in the context of defects in the ability to transport cholesterol (e.g., expression of the high-risk APOE4 isoform), can lead to chronic activation, increased inflammatory signaling, and reduced phagocytic capacity, which have been associated with AD pathology. In this narrative review we describe how cholesterol regulates microglia phenotype and function, and discuss what is known about the effects of statins on microglia, as well as highlighting areas of future research to advance knowledge that can lead to the development of novel therapies for the prevention and treatment of AD.
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7
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Margiotta A. Membrane Fusion and SNAREs: Interaction with Ras Proteins. Int J Mol Sci 2022; 23:ijms23158067. [PMID: 35897641 PMCID: PMC9330862 DOI: 10.3390/ijms23158067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 06/30/2022] [Accepted: 07/19/2022] [Indexed: 12/10/2022] Open
Abstract
The superfamily of Ras proteins comprises different molecules belonging to the GTPase family. They normally cycle between an active state bound to GTP which activates effectors while the protein is membrane-associated, and an inactive GDP-bound state. They regulate the intracellular trafficking and other cellular processes. The family of Rab proteins includes several members and they have been found, among other Ras proteins, to be fundamental for important biological processes, such as endocytosis and exocytosis. SNARE proteins control the fusion of vesicles by forming quaternary complexes which are divided into two small groups on the two different compartments. Generally, the association of three SNARE proteins on the donor compartment with the one on the target compartment determines the formation of the SNARE complex, the opening of the fusion pore and the formation of one single bigger vesicle. Interestingly, novel interactions between other molecules involved in intracellular trafficking, endosomal fusion and maturation have recently been found, such as the interaction between invariant chain and the Qb SNARE vti1b, and more functional connections between Rab proteins and SNAREs are supposed to be fundamental for the regulation of membrane fusion.
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8
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Linking Late Endosomal Cholesterol with Cancer Progression and Anticancer Drug Resistance. Int J Mol Sci 2022; 23:ijms23137206. [PMID: 35806209 PMCID: PMC9267071 DOI: 10.3390/ijms23137206] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 06/22/2022] [Accepted: 06/25/2022] [Indexed: 11/16/2022] Open
Abstract
Cancer cells undergo drastic metabolic adaptions to cover increased bioenergetic needs, contributing to resistance to therapies. This includes a higher demand for cholesterol, which often coincides with elevated cholesterol uptake from low-density lipoproteins (LDL) and overexpression of the LDL receptor in many cancers. This implies the need for cancer cells to accommodate an increased delivery of LDL along the endocytic pathway to late endosomes/lysosomes (LE/Lys), providing a rapid and effective distribution of LDL-derived cholesterol from LE/Lys to other organelles for cholesterol to foster cancer growth and spread. LDL-cholesterol exported from LE/Lys is facilitated by Niemann–Pick Type C1/2 (NPC1/2) proteins, members of the steroidogenic acute regulatory-related lipid transfer domain (StARD) and oxysterol-binding protein (OSBP) families. In addition, lysosomal membrane proteins, small Rab GTPases as well as scaffolding proteins, including annexin A6 (AnxA6), contribute to regulating cholesterol egress from LE/Lys. Here, we summarize current knowledge that links upregulated activity and expression of cholesterol transporters and related proteins in LE/Lys with cancer growth, progression and treatment outcomes. Several mechanisms on how cellular distribution of LDL-derived cholesterol from LE/Lys influences cancer cell behavior are reviewed, some of those providing opportunities for treatment strategies to reduce cancer progression and anticancer drug resistance.
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9
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Chang TY, Chang CCY, Harned TC, De La Torre AL, Lee J, Huynh TN, Gow JG. Blocking cholesterol storage to treat Alzheimer's disease. EXPLORATION OF NEUROPROTECTIVE THERAPY 2021; 1:173-184. [PMID: 35199105 PMCID: PMC8863366 DOI: 10.37349/ent.2021.00014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cholesterol serves as an essential lipid molecule in various membrane organelles of mammalian cells. The metabolites of cholesterol also play important functions. Acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1), also named as sterol O-acyltransferase 1, is a membrane-bound enzyme residing at the endoplasmic reticulum (ER). It converts cholesterol to cholesteryl esters (CEs) for storage, and is expressed in all cells. CEs cannot partition in membranes; they can only coalesce as cytosolic lipid droplets. Excess CEs are found in the vulnerable region of the brains of patients with late-onset Alzheimer's disease (AD), and in cell and mouse models for AD. Reducing CE contents by genetic inactivation of ACAT1, or by pharmacological inhibition of ACAT is shown to reduce amyloidopathy and other hallmarks for AD. To account for the various beneficial actions of the ACAT1 blockade (A1B), a working hypothesis is proposed here: the increase in CE contents observed in the AD brain is caused by damages of cholesterol-rich lipid rafts that are known to occur in neurons affected by AD. These damages cause cholesterol to release from lipid rafts and move to the ER where it will be converted to CEs by ACAT1. In addition, the increase in CE contents may also be caused by overloading with cholesterol-rich substances, or through activation of ACAT1 gene expression by various proinflammatory agents. Both scenarios may occur in microglia of the chronically inflamed brain. A1B ameliorates AD by diverting the cholesterol pool destined for CE biosynthesis such that it can be utilized more efficiently to repair membrane damage in various organelles, and to exert regulatory actions more effectively to defend against AD. To test the validity of the A1B hypothesis in cell culture and in vivo, the current status of various anti-ACAT1 agents that could be further developed is briefly discussed.
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Affiliation(s)
- Ta Yuan Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Catherine C Y Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Taylor C Harned
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Adrianna L De La Torre
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Junghoon Lee
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Thao N Huynh
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - James G Gow
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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10
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Lingwood C. Therapeutic Uses of Bacterial Subunit Toxins. Toxins (Basel) 2021; 13:toxins13060378. [PMID: 34073185 PMCID: PMC8226680 DOI: 10.3390/toxins13060378] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 02/07/2023] Open
Abstract
The B subunit pentamer verotoxin (VT aka Shiga toxin-Stx) binding to its cellular glycosphingolipid (GSL) receptor, globotriaosyl ceramide (Gb3) mediates internalization and the subsequent receptor mediated retrograde intracellular traffic of the AB5 subunit holotoxin to the endoplasmic reticulum. Subunit separation and cytosolic A subunit transit via the ER retrotranslocon as a misfolded protein mimic, then inhibits protein synthesis to kill cells, which can cause hemolytic uremic syndrome clinically. This represents one of the most studied systems of prokaryotic hijacking of eukaryotic biology. Similarly, the interaction of cholera AB5 toxin with its GSL receptor, GM1 ganglioside, is the key component of the gastrointestinal pathogenesis of cholera and follows the same retrograde transport pathway for A subunit cytosol access. Although both VT and CT are the cause of major pathology worldwide, the toxin–receptor interaction is itself being manipulated to generate new approaches to control, rather than cause, disease. This arena comprises two areas: anti neoplasia, and protein misfolding diseases. CT/CTB subunit immunomodulatory function and anti-cancer toxin immunoconjugates will not be considered here. In the verotoxin case, it is clear that Gb3 (and VT targeting) is upregulated in many human cancers and that there is a relationship between GSL expression and cancer drug resistance. While both verotoxin and cholera toxin similarly hijack the intracellular ERAD quality control system of nascent protein folding, the more widespread cell expression of GM1 makes cholera the toxin of choice as the means to more widely utilise ERAD targeting to ameliorate genetic diseases of protein misfolding. Gb3 is primarily expressed in human renal tissue. Glomerular endothelial cells are the primary VT target but Gb3 is expressed in other endothelial beds, notably brain endothelial cells which can mediate the encephalopathy primarily associated with VT2-producing E. coli infection. The Gb3 levels can be regulated by cytokines released during EHEC infection, which complicate pathogenesis. Significantly Gb3 is upregulated in the neovasculature of many tumours, irrespective of tumour Gb3 status. Gb3 is markedly increased in pancreatic, ovarian, breast, testicular, renal, astrocytic, gastric, colorectal, cervical, sarcoma and meningeal cancer relative to the normal tissue. VT has been shown to be effective in mouse xenograft models of renal, astrocytoma, ovarian, colorectal, meningioma, and breast cancer. These studies are herein reviewed. Both CT and VT (and several other bacterial toxins) access the cell cytosol via cell surface ->ER transport. Once in the ER they interface with the protein folding homeostatic quality control pathway of the cell -ERAD, (ER associated degradation), which ensures that only correctly folded nascent proteins are allowed to progress to their cellular destinations. Misfolded proteins are translocated through the ER membrane and degraded by cytosolic proteosome. VT and CT A subunits have a C terminal misfolded protein mimic sequence to hijack this transporter to enter the cytosol. This interface between exogenous toxin and genetically encoded endogenous mutant misfolded proteins, provides a new therapeutic basis for the treatment of such genetic diseases, e.g., Cystic fibrosis, Gaucher disease, Krabbe disease, Fabry disease, Tay-Sachs disease and many more. Studies showing the efficacy of this approach in animal models of such diseases are presented.
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Affiliation(s)
- Clifford Lingwood
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada;
- Departments of Laboratory Medicine & Pathobiology, and Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
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11
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Cortada E, Serradesanferm R, Brugada R, Verges M. The voltage-gated sodium channel β2 subunit associates with lipid rafts by S-palmitoylation. J Cell Sci 2021; 134:jcs.252189. [PMID: 33602743 DOI: 10.1242/jcs.252189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 02/08/2021] [Indexed: 12/19/2022] Open
Abstract
The voltage-gated sodium channel is critical for cardiomyocyte function. It consists of a protein complex comprising a pore-forming α subunit and associated β subunits. In polarized Madin-Darby canine kidney cells, we show evidence by acyl-biotin exchange that β2 is S-acylated at Cys-182. Interestingly, we found that palmitoylation increases β2 association with detergent-resistant membranes. β2 localizes exclusively to the apical surface. However, depletion of plasma membrane cholesterol, or blocking intracellular cholesterol transport, caused mislocalization of β2, as well as of the non-palmitoylable C182S mutant, to the basolateral domain. Apical β2 did not undergo endocytosis and displayed limited diffusion within the plane of the membrane; such behavior suggests that, at least in part, it is cytoskeleton anchored. Upon acute cholesterol depletion, its mobility was greatly reduced, and a slight reduction was also measured as a result of lack of palmitoylation, supporting β2 association with cholesterol-rich lipid rafts. Indeed, lipid raft labeling confirmed a partial overlap with apical β2. Although β2 palmitoylation was not required to promote surface localization of the α subunit, our data suggest that it is likely implicated in lipid raft association and the polarized localization of β2.
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Affiliation(s)
- Eric Cortada
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain
| | - Robert Serradesanferm
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain.,Medical Sciences Department, University of Girona Medical School, 17071 Girona, Spain.,Cardiology Department, Hospital Josep Trueta - University of Girona Medical School, 17007 Girona, Spain
| | - Marcel Verges
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain .,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain.,Medical Sciences Department, University of Girona Medical School, 17071 Girona, Spain
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12
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Meneses-Salas E, Garcia-Forn M, Castany-Pladevall C, Lu A, Fajardo A, Jose J, Wahba M, Bosch M, Pol A, Tebar F, Klein AD, Zanlungo S, Pérez-Navarro E, Grewal T, Enrich C, Rentero C. Lack of Annexin A6 Exacerbates Liver Dysfunction and Reduces Lifespan of Niemann-Pick Type C Protein-Deficient Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 191:475-486. [PMID: 33345999 DOI: 10.1016/j.ajpath.2020.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 11/25/2020] [Accepted: 12/09/2020] [Indexed: 12/12/2022]
Abstract
Niemann-Pick type C (NPC) disease is a lysosomal storage disorder characterized by cholesterol accumulation caused by loss-of-function mutations in the Npc1 gene. NPC disease primarily affects the brain, causing neuronal damage and affecting motor coordination. In addition, considerable liver malfunction in NPC disease is common. Recently, we found that the depletion of annexin A6 (ANXA6), which is most abundant in the liver and involved in cholesterol transport, ameliorated cholesterol accumulation in Npc1 mutant cells. To evaluate the potential contribution of ANXA6 in the progression of NPC disease, double-knockout mice (Npc1-/-/Anxa6-/-) were generated and examined for lifespan, neurologic and hepatic functions, as well as liver histology and ultrastructure. Interestingly, lack of ANXA6 in NPC1-deficient animals did not prevent the cerebellar degeneration phenotype, but further deteriorated their compromised hepatic functions and reduced their lifespan. Moreover, livers of Npc1-/-/Anxa6-/- mice contained a significantly elevated number of foam cells congesting the sinusoidal space, a feature commonly associated with inflammation. We hypothesize that ANXA6 deficiency in Npc1-/- mice not only does not reverse neurologic and motor dysfunction, but further worsens overall liver function, exacerbating hepatic failure in NPC disease.
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Affiliation(s)
- Elsa Meneses-Salas
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Marta Garcia-Forn
- Institut de Neurociències, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Carla Castany-Pladevall
- Institut de Neurociències, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Albert Lu
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain; Institut de Neurociències, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Department of Biochemistry, Stanford University School of Medicine, Stanford, California
| | - Alba Fajardo
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Jaimy Jose
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Mohamed Wahba
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Marta Bosch
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Albert Pol
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Universidad del Desarrollo, Clínica Alemana de Santiago, Chile
| | - Francesc Tebar
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Andrés D Klein
- Centro de Genética y Genómica, Universidad del Desarrollo, Clínica Alemana de Santiago, Chile
| | - Silvana Zanlungo
- Departamento de Gastroenterología, Facultad de Medicina Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Esther Pérez-Navarro
- Institut de Neurociències, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Carlos Enrich
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
| | - Carles Rentero
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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13
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Alvarez-Guaita A, Blanco-Muñoz P, Meneses-Salas E, Wahba M, Pollock AH, Jose J, Casado M, Bosch M, Artuch R, Gaus K, Lu A, Pol A, Tebar F, Moss SE, Grewal T, Enrich C, Rentero C. Annexin A6 Is Critical to Maintain Glucose Homeostasis and Survival During Liver Regeneration in Mice. Hepatology 2020; 72:2149-2164. [PMID: 32170749 DOI: 10.1002/hep.31232] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/20/2020] [Accepted: 02/28/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND AIMS Liver regeneration requires the organized and sequential activation of events that lead to restoration of hepatic mass. During this process, other vital liver functions need to be preserved, such as maintenance of blood glucose homeostasis, balancing the degradation of hepatic glycogen stores, and gluconeogenesis (GNG). Under metabolic stress, alanine is the main hepatic gluconeogenic substrate, and its availability is the rate-limiting step in this pathway. Na+ -coupled neutral amino acid transporters (SNATs) 2 and 4 are believed to facilitate hepatic alanine uptake. In previous studies, we demonstrated that a member of the Ca2+ -dependent phospholipid binding annexins, Annexin A6 (AnxA6), regulates membrane trafficking along endo- and exocytic pathways. Yet, although AnxA6 is abundantly expressed in the liver, its function in hepatic physiology remains unknown. In this study, we investigated the potential contribution of AnxA6 in liver regeneration. APPROACH AND RESULTS Utilizing AnxA6 knockout mice (AnxA6-/- ), we challenged liver function after partial hepatectomy (PHx), inducing acute proliferative and metabolic stress. Biochemical and immunofluorescent approaches were used to dissect AnxA6-/- mice liver proliferation and energetic metabolism. Most strikingly, AnxA6-/- mice exhibited low survival after PHx. This was associated with an irreversible and progressive drop of blood glucose levels. Whereas exogenous glucose administration or restoration of hepatic AnxA6 expression rescued AnxA6-/- mice survival after PHx, the sustained hypoglycemia in partially hepatectomized AnxA6-/- mice was the consequence of an impaired alanine-dependent GNG in AnxA6-/- hepatocytes. Mechanistically, cytoplasmic SNAT4 failed to recycle to the sinusoidal plasma membrane of AnxA6-/- hepatocytes 48 hours after PHx, impairing alanine uptake and, consequently, glucose production. CONCLUSIONS We conclude that the lack of AnxA6 compromises alanine-dependent GNG and liver regeneration in mice.
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Affiliation(s)
- Anna Alvarez-Guaita
- Unit of Cell Biology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.,Currently at Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Patricia Blanco-Muñoz
- Unit of Cell Biology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.,Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Elsa Meneses-Salas
- Unit of Cell Biology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.,Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Mohamed Wahba
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Abigail H Pollock
- Center for Vascular Research, The University of New South Wales, Sydney, NSW, Australia
| | - Jaimy Jose
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Mercedes Casado
- Clinical Biochemistry Department, Institut de Recerca Sant Joan de Déu and CIBERER, Barcelona, Spain
| | - Marta Bosch
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Rafael Artuch
- Clinical Biochemistry Department, Institut de Recerca Sant Joan de Déu and CIBERER, Barcelona, Spain
| | - Katharina Gaus
- Center for Vascular Research, The University of New South Wales, Sydney, NSW, Australia
| | - Albert Lu
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA
| | - Albert Pol
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Francesc Tebar
- Unit of Cell Biology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.,Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Stephen E Moss
- Institute of Ophthalmology, University College of London, London, United Kingdom
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Carlos Enrich
- Unit of Cell Biology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.,Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Carles Rentero
- Unit of Cell Biology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.,Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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14
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Korolkova OY, Widatalla SE, Williams SD, Whalen DS, Beasley HK, Ochieng J, Grewal T, Sakwe AM. Diverse Roles of Annexin A6 in Triple-Negative Breast Cancer Diagnosis, Prognosis and EGFR-Targeted Therapies. Cells 2020; 9:E1855. [PMID: 32784650 PMCID: PMC7465958 DOI: 10.3390/cells9081855] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 12/20/2022] Open
Abstract
The calcium (Ca2+)-dependent membrane-binding Annexin A6 (AnxA6), is a multifunctional, predominantly intracellular scaffolding protein, now known to play relevant roles in different cancer types through diverse, often cell-type-specific mechanisms. AnxA6 is differentially expressed in various stages/subtypes of several cancers, and its expression in certain tumor cells is also induced by a variety of pharmacological drugs. Together with the secretion of AnxA6 as a component of extracellular vesicles, this suggests that AnxA6 mediates distinct tumor progression patterns via extracellular and/or intracellular activities. Although it lacks enzymatic activity, some of the AnxA6-mediated functions involving membrane, nucleotide and cholesterol binding as well as the scaffolding of specific proteins or multifactorial protein complexes, suggest its potential utility in the diagnosis, prognosis and therapeutic strategies for various cancers. In breast cancer, the low AnxA6 expression levels in the more aggressive basal-like triple-negative breast cancer (TNBC) subtype correlate with its tumor suppressor activity and the poor overall survival of basal-like TNBC patients. In this review, we highlight the potential tumor suppressor function of AnxA6 in TNBC progression and metastasis, the relevance of AnxA6 in the diagnosis and prognosis of several cancers and discuss the concept of therapy-induced expression of AnxA6 as a novel mechanism for acquired resistance of TNBC to tyrosine kinase inhibitors.
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Affiliation(s)
- Olga Y. Korolkova
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Sarrah E. Widatalla
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Stephen D. Williams
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Diva S. Whalen
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Heather K. Beasley
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Josiah Ochieng
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia;
| | - Amos M. Sakwe
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
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15
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Bouza AA, Philippe JM, Edokobi N, Pinsky AM, Offord J, Calhoun JD, Lopez-Florán M, Lopez-Santiago LF, Jenkins PM, Isom LL. Sodium channel β1 subunits are post-translationally modified by tyrosine phosphorylation, S-palmitoylation, and regulated intramembrane proteolysis. J Biol Chem 2020; 295:10380-10393. [PMID: 32503841 PMCID: PMC7383382 DOI: 10.1074/jbc.ra120.013978] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/02/2020] [Indexed: 01/05/2023] Open
Abstract
Voltage-gated sodium channel (VGSC) β1 subunits are multifunctional proteins that modulate the biophysical properties and cell-surface localization of VGSC α subunits and participate in cell-cell and cell-matrix adhesion, all with important implications for intracellular signal transduction, cell migration, and differentiation. Human loss-of-function variants in SCN1B, the gene encoding the VGSC β1 subunits, are linked to severe diseases with high risk for sudden death, including epileptic encephalopathy and cardiac arrhythmia. We showed previously that β1 subunits are post-translationally modified by tyrosine phosphorylation. We also showed that β1 subunits undergo regulated intramembrane proteolysis via the activity of β-secretase 1 and γ-secretase, resulting in the generation of a soluble intracellular domain, β1-ICD, which modulates transcription. Here, we report that β1 subunits are phosphorylated by FYN kinase. Moreover, we show that β1 subunits are S-palmitoylated. Substitution of a single residue in β1, Cys-162, to alanine prevented palmitoylation, reduced the level of β1 polypeptides at the plasma membrane, and reduced the extent of β1-regulated intramembrane proteolysis, suggesting that the plasma membrane is the site of β1 proteolytic processing. Treatment with the clathrin-mediated endocytosis inhibitor, Dyngo-4a, re-stored the plasma membrane association of β1-p.C162A to WT levels. Despite these observations, palmitoylation-null β1-p.C162A modulated sodium current and sorted to detergent-resistant membrane fractions normally. This is the first demonstration of S-palmitoylation of a VGSC β subunit, establishing precedence for this post-translational modification as a regulatory mechanism in this protein family.
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Affiliation(s)
- Alexandra A Bouza
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Julie M Philippe
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Nnamdi Edokobi
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alexa M Pinsky
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - James Offord
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jeffrey D Calhoun
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Mariana Lopez-Florán
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Luis F Lopez-Santiago
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Psychiatry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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16
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Meneses-Salas E, García-Melero A, Blanco-Muñoz P, Jose J, Brenner MS, Lu A, Tebar F, Grewal T, Rentero C, Enrich C. Selective Degradation Permits a Feedback Loop Controlling Annexin A6 and Cholesterol Levels in Endolysosomes of NPC1 Mutant Cells. Cells 2020; 9:cells9051152. [PMID: 32392809 PMCID: PMC7291204 DOI: 10.3390/cells9051152] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 04/23/2020] [Accepted: 05/05/2020] [Indexed: 12/22/2022] Open
Abstract
We recently identified elevated annexin A6 (AnxA6) protein levels in Niemann–Pick-type C1 (NPC1) mutant cells. In these cells, AnxA6 depletion rescued the cholesterol accumulation associated with NPC1 deficiency. Here, we demonstrate that elevated AnxA6 protein levels in NPC1 mutants or upon pharmacological NPC1 inhibition, using U18666A, were not due to upregulated AnxA6 mRNA expression, but caused by defects in AnxA6 protein degradation. Two KFERQ-motifs are believed to target AnxA6 to lysosomes for chaperone-mediated autophagy (CMA), and we hypothesized that the cholesterol accumulation in endolysosomes (LE/Lys) triggered by the NPC1 inhibition could interfere with the CMA pathway. Therefore, AnxA6 protein amounts and cholesterol levels in the LE/Lys (LE-Chol) compartment were analyzed in NPC1 mutant cells ectopically expressing lysosome-associated membrane protein 2A (Lamp2A), which is well known to induce the CMA pathway. Strikingly, AnxA6 protein amounts were strongly decreased and coincided with significantly reduced LE-Chol levels in NPC1 mutant cells upon Lamp2A overexpression. Therefore, these findings suggest Lamp2A-mediated restoration of CMA in NPC1 mutant cells to lower LE-Chol levels with concomitant lysosomal AnxA6 degradation. Collectively, we propose CMA to permit a feedback loop between AnxA6 and cholesterol levels in LE/Lys, encompassing a novel mechanism for regulating cholesterol homeostasis in NPC1 disease.
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Affiliation(s)
- Elsa Meneses-Salas
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain; (E.M.-S.); (A.G.-M.); (P.B.-M.); (F.T.)
- Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036-Barcelona, Spain
| | - Ana García-Melero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain; (E.M.-S.); (A.G.-M.); (P.B.-M.); (F.T.)
- Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036-Barcelona, Spain
| | - Patricia Blanco-Muñoz
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain; (E.M.-S.); (A.G.-M.); (P.B.-M.); (F.T.)
- Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036-Barcelona, Spain
| | - Jaimy Jose
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney 2006, NSW, Australia; (J.J.); (M.-S.B.)
| | - Marie-Sophie Brenner
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney 2006, NSW, Australia; (J.J.); (M.-S.B.)
| | - Albert Lu
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA;
| | - Francesc Tebar
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain; (E.M.-S.); (A.G.-M.); (P.B.-M.); (F.T.)
- Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036-Barcelona, Spain
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney 2006, NSW, Australia; (J.J.); (M.-S.B.)
- Correspondence: (T.G.); (C.R.); (C.E.); Tel.: +34-934021908 (C.R.)
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain; (E.M.-S.); (A.G.-M.); (P.B.-M.); (F.T.)
- Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036-Barcelona, Spain
- Correspondence: (T.G.); (C.R.); (C.E.); Tel.: +34-934021908 (C.R.)
| | - Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain; (E.M.-S.); (A.G.-M.); (P.B.-M.); (F.T.)
- Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036-Barcelona, Spain
- Correspondence: (T.G.); (C.R.); (C.E.); Tel.: +34-934021908 (C.R.)
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17
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Hoque M, Elmaghrabi YA, Köse M, Beevi SS, Jose J, Meneses-Salas E, Blanco-Muñoz P, Conway JRW, Swarbrick A, Timpson P, Tebar F, Enrich C, Rentero C, Grewal T. Annexin A6 improves anti-migratory and anti-invasive properties of tyrosine kinase inhibitors in EGFR overexpressing human squamous epithelial cells. FEBS J 2020; 287:2961-2978. [PMID: 31869496 DOI: 10.1111/febs.15186] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/22/2019] [Accepted: 12/18/2019] [Indexed: 01/12/2023]
Abstract
Annexin A6 (AnxA6), a member of the calcium (Ca2+ ) and membrane binding annexins, is known to stabilize and establish the formation of multifactorial signaling complexes. At the plasma membrane, AnxA6 is a scaffold for protein kinase Cα (PKCα) and GTPase-activating protein p120GAP to promote downregulation of epidermal growth factor receptor (EGFR) and Ras/mitogen-activated protein kinase (MAPK) signaling. In human squamous A431 epithelial carcinoma cells, which overexpress EGFR, but lack endogenous AnxA6, restoration of AnxA6 expression (A431-A6) promotes PKCα-mediated threonine 654 (T654)-EGFR phosphorylation, which inhibits EGFR tyrosine kinase activity. This is associated with reduced A431-A6 cell growth, but also decreased migration and invasion in wound healing, matrigel, and organotypic matrices. Here, we show that A431-A6 cells display reduced EGFR activity in vivo, with xenograft analysis identifying increased pT654-EGFR levels, but reduced tyrosine EGFR phosphorylation compared to controls. In contrast, PKCα depletion in A431-A6 tumors is associated with strongly reduced pT654 EGFR levels, yet increased EGFR tyrosine phosphorylation and MAPK activity. Moreover, tyrosine kinase inhibitors (TKIs; gefitinib, erlotinib) more effectively inhibit cell viability, clonogenic growth, and wound healing of A431-A6 cells compared to controls. Likewise, the ability of AnxA6 to inhibit A431 motility and invasiveness strongly improves TKI efficacy in matrigel invasion assays. This correlates with a greatly reduced invasion of the surrounding matrix of TKI-treated A431-A6 when cultured in 3D spheroids. Altogether, these findings implicate that elevated AnxA6 scaffold levels contribute to improve TKI-mediated inhibition of growth and migration, but also invasive properties in EGFR overexpressing human squamous epithelial carcinoma.
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Affiliation(s)
- Monira Hoque
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Yasmin A Elmaghrabi
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Meryem Köse
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Syed S Beevi
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Jaimy Jose
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Elsa Meneses-Salas
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, IDIBAPS, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Spain
| | - Patricia Blanco-Muñoz
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, IDIBAPS, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Spain
| | - James R W Conway
- Cancer Research Program, Garvan Institute of Medical Research and Kinghorn Cancer Centre, Sydney, NSW, Australia.,Faculty of Medicine, St. Vincent's Clinical School, University of New South Wales Sydney, NSW, Australia
| | - Alexander Swarbrick
- Cancer Research Program, Garvan Institute of Medical Research and Kinghorn Cancer Centre, Sydney, NSW, Australia.,Faculty of Medicine, St. Vincent's Clinical School, University of New South Wales Sydney, NSW, Australia
| | - Paul Timpson
- Cancer Research Program, Garvan Institute of Medical Research and Kinghorn Cancer Centre, Sydney, NSW, Australia.,Faculty of Medicine, St. Vincent's Clinical School, University of New South Wales Sydney, NSW, Australia
| | - Francesc Tebar
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, IDIBAPS, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Spain
| | - Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, IDIBAPS, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Spain
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, IDIBAPS, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Spain
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, NSW, Australia
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18
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Peak TC, Panigrahi GK, Praharaj P, Su Y, Shi L, Chyr J, Rivera-Chávez J, Flores-Bocanegra L, Singh R, Vander Griend DJ, Oberlies NH, Kerr BA, Hemal A, Bitting RL, Deep G. Syntaxin 6-mediated exosome secretion regulates enzalutamide resistance in prostate cancer. Mol Carcinog 2020; 59:62-72. [PMID: 31674708 PMCID: PMC6916724 DOI: 10.1002/mc.23129] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/16/2019] [Accepted: 10/17/2019] [Indexed: 12/12/2022]
Abstract
Prostate cancer (PCa) deaths are typically the result of metastatic castration-resistant PCa (mCRPC). Recently, enzalutamide (Enz), an oral androgen receptor inhibitor, was approved for treating patients with mCRPC. Invariably, all PCa patients eventually develop resistance against Enz. Therefore, novel strategies aimed at overcoming Enz resistance are needed to improve the survival of PCa patients. The role of exosomes in drug resistance has not been fully elucidated in PCa. Therefore, we set out to better understand the exosome's role in the mechanism underlying Enz-resistant PCa. Results showed that Enz-resistant PCa cells (C4-2B, CWR-R1, and LNCaP) secreted significantly higher amounts of exosomes (2-4 folds) compared to Enz-sensitive counterparts. Inhibition of exosome biogenesis in resistant cells by GW4869 and dimethyl amiloride strongly decreased their cell viability. Mechanistic studies revealed upregulation of syntaxin 6 as well as its increased colocalization with CD63 in Enz-resistant PCa cells compared to Enz-sensitive cells. Syntaxin 6 knockdown by specific small interfering RNAs in Enz-resistant PCa cells (C4-2B and CWR-R1) resulted in reduced cell number and increased cell death in the presence of Enz. Furthermore, syntaxin 6 knockdown significantly reduced the exosome secretion in both Enz-resistant C4-2B and CWR-R1 cells. The Cancer Genome Atlas analysis showed increased syntaxin 6 expressions associated with higher Gleason score and decreased progression-free survival in PCa patients. Importantly, IHC analysis showed higher syntaxin 6 expression in cancer tissues from Enz-treated patients compared to Enz naïve patients. Overall, syntaxin 6 plays an important role in the secretion of exosomes and increased survival of Enz-resistant PCa cells.
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Affiliation(s)
- Taylor C. Peak
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Gati K Panigrahi
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Prakash Praharaj
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Yixin Su
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Lihong Shi
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jacqueline Chyr
- School of Bioinformatics, University of Texas Health Science Center, Houston, Texas
| | - José Rivera-Chávez
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro; Greensboro, North Carolina
| | - Laura Flores-Bocanegra
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro; Greensboro, North Carolina
| | - Ravi Singh
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | | | - Nicholas H. Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro; Greensboro, North Carolina
| | - Bethany A. Kerr
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Wake Forest Baptist Comprehensive Cancer Center
- Department of Urology
| | | | - Rhonda L. Bitting
- Internal Medicine-Hematology and Oncology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Gagan Deep
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Wake Forest Baptist Comprehensive Cancer Center
- Department of Urology
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19
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Miyagawa T, Hasegawa K, Aoki Y, Watanabe T, Otagiri Y, Arasaki K, Wakana Y, Asano K, Tanaka M, Yamaguchi H, Tagaya M, Inoue H. MT1-MMP recruits the ER-Golgi SNARE Bet1 for efficient MT1-MMP transport to the plasma membrane. J Cell Biol 2019; 218:3355-3371. [PMID: 31519727 PMCID: PMC6781441 DOI: 10.1083/jcb.201808149] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 04/22/2019] [Accepted: 07/09/2019] [Indexed: 12/17/2022] Open
Abstract
Invasive cancer cells degrade and invade into the extracellular matrix by expressing the matrix metalloproteinase MT1-MMP at invadopodia. Miyagawa et al. show that MT1-MMP uses the ER-Golgi SNARE Bet1 to facilitate its own transport to the plasma membrane through their interaction in a cholesterol-rich milieu. Metastasis is a major cause of cancer-related death. Membrane type 1–matrix metalloproteinase (MT1-MMP) is a critical protease for local invasion and metastasis. MT1-MMP is synthesized in the endoplasmic reticulum (ER) and transported in vesicles to invadopodia, specialized subdomains of the plasma membrane, through secretory and endocytic recycling pathways. The molecular mechanism underlying intracellular transport of MT1-MMP has been extensively studied, but is not fully understood. We show that MT1-MMP diverts the SNARE Bet1 from its function in ER-Golgi transport, to promote MT1-MMP trafficking to the cell surface, likely to invadopodia. In invasive cells, Bet1 is localized in MT1-MMP–positive endosomes in addition to the Golgi apparatus, and forms a novel SNARE complex with syntaxin 4 and endosomal SNAREs. MT1-MMP may also use Bet1 for its export from raft-like structures in the ER. Our results suggest the recruitment of Bet1 at an early stage after MT1-MMP expression promotes the exit of MT1-MMP from the ER and its efficient transport to invadopodia.
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Affiliation(s)
- Takuya Miyagawa
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Kana Hasegawa
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Yoko Aoki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Takuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Yuka Otagiri
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Kohei Arasaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Yuichi Wakana
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Kenichi Asano
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Masato Tanaka
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hideki Yamaguchi
- Department of Cancer Cell Research, Sasaki Institute, Sasaki Foundation, Chiyoda-ku, Tokyo, Japan
| | - Mitsuo Tagaya
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hiroki Inoue
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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20
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Grewal T, Enrich C, Rentero C, Buechler C. Annexins in Adipose Tissue: Novel Players in Obesity. Int J Mol Sci 2019; 20:ijms20143449. [PMID: 31337068 PMCID: PMC6678658 DOI: 10.3390/ijms20143449] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 12/12/2022] Open
Abstract
Obesity and the associated comorbidities are a growing health threat worldwide. Adipose tissue dysfunction, impaired adipokine activity, and inflammation are central to metabolic diseases related to obesity. In particular, the excess storage of lipids in adipose tissues disturbs cellular homeostasis. Amongst others, organelle function and cell signaling, often related to the altered composition of specialized membrane microdomains (lipid rafts), are affected. Within this context, the conserved family of annexins are well known to associate with membranes in a calcium (Ca2+)- and phospholipid-dependent manner in order to regulate membrane-related events, such as trafficking in endo- and exocytosis and membrane microdomain organization. These multiple activities of annexins are facilitated through their diverse interactions with a plethora of lipids and proteins, often in different cellular locations and with consequences for the activity of receptors, transporters, metabolic enzymes, and signaling complexes. While increasing evidence points at the function of annexins in lipid homeostasis and cell metabolism in various cells and organs, their role in adipose tissue, obesity and related metabolic diseases is still not well understood. Annexin A1 (AnxA1) is a potent pro-resolving mediator affecting the regulation of body weight and metabolic health. Relevant for glucose metabolism and fatty acid uptake in adipose tissue, several studies suggest AnxA2 to contribute to coordinate glucose transporter type 4 (GLUT4) translocation and to associate with the fatty acid transporter CD36. On the other hand, AnxA6 has been linked to the control of adipocyte lipolysis and adiponectin release. In addition, several other annexins are expressed in fat tissues, yet their roles in adipocytes are less well examined. The current review article summarizes studies on the expression of annexins in adipocytes and in obesity. Research efforts investigating the potential role of annexins in fat tissue relevant to health and metabolic disease are discussed.
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Affiliation(s)
- Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Carlos Enrich
- Department of Biomedicine, Unit of Cell Biology, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Carles Rentero
- Department of Biomedicine, Unit of Cell Biology, Faculty of Medicine and Health Sciences, University of Barcelona, 08036 Barcelona, Spain
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Christa Buechler
- Department of Internal Medicine I, Regensburg University Hospital, 93053 Regensburg, Germany.
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21
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Cairns R, Fischer AW, Blanco-Munoz P, Alvarez-Guaita A, Meneses-Salas E, Egert A, Buechler C, Hoy AJ, Heeren J, Enrich C, Rentero C, Grewal T. Altered hepatic glucose homeostasis in AnxA6-KO mice fed a high-fat diet. PLoS One 2018; 13:e0201310. [PMID: 30110341 PMCID: PMC6093612 DOI: 10.1371/journal.pone.0201310] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 07/12/2018] [Indexed: 12/12/2022] Open
Abstract
Annexin A6 (AnxA6) controls cholesterol and membrane transport in endo- and exocytosis, and modulates triglyceride accumulation and storage. In addition, AnxA6 acts as a scaffolding protein for negative regulators of growth factor receptors and their effector pathways in many different cell types. Here we investigated the role of AnxA6 in the regulation of whole body lipid metabolism and insulin-regulated glucose homeostasis. Therefore, wildtype (WT) and AnxA6-knockout (KO) mice were fed a high-fat diet (HFD) for 17 weeks. During the course of HFD feeding, AnxA6-KO mice gained less weight compared to controls, which correlated with reduced adiposity. Systemic triglyceride and cholesterol levels of HFD-fed control and AnxA6-KO mice were comparable, with slightly elevated high density lipoprotein (HDL) and reduced triglyceride-rich lipoprotein (TRL) levels in AnxA6-KO mice. AnxA6-KO mice displayed a trend towards improved insulin sensitivity in oral glucose and insulin tolerance tests (OGTT, ITT), which correlated with increased insulin-inducible phosphorylation of protein kinase B (Akt) and ribosomal protein S6 kinase (S6) in liver extracts. However, HFD-fed AnxA6-KO mice failed to downregulate hepatic gluconeogenesis, despite similar insulin levels and insulin signaling activity, as well as expression profiles of insulin-sensitive transcription factors to controls. In addition, increased glycogen storage in livers of HFD- and chow-fed AnxA6-KO animals was observed. Together with an inability to reduce glucose production upon insulin exposure in AnxA6-depleted HuH7 hepatocytes, this implicates AnxA6 contributing to the fine-tuning of hepatic glucose metabolism with potential consequences for the systemic control of glucose in health and disease.
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Affiliation(s)
- Rose Cairns
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Alexander W. Fischer
- Department of Biochemistry and Molecular Biology II: Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Patricia Blanco-Munoz
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Anna Alvarez-Guaita
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Elsa Meneses-Salas
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Antonia Egert
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Christa Buechler
- Department of Internal Medicine I, Regensburg University Hospital, Regensburg, Germany
| | - Andrew J. Hoy
- Discipline of Physiology, School of Medical Science, Sydney Medical School, Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
| | - Joerg Heeren
- Department of Biochemistry and Molecular Biology II: Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
- * E-mail: (TG); (CR)
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
- * E-mail: (TG); (CR)
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22
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Barbero-Camps E, Roca-Agujetas V, Bartolessis I, de Dios C, Fernández-Checa JC, Marí M, Morales A, Hartmann T, Colell A. Cholesterol impairs autophagy-mediated clearance of amyloid beta while promoting its secretion. Autophagy 2018; 14:1129-1154. [PMID: 29862881 PMCID: PMC6103708 DOI: 10.1080/15548627.2018.1438807] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Macroautophagy/autophagy failure with the accumulation of autophagosomes is an early neuropathological feature of Alzheimer disease (AD) that directly affects amyloid beta (Aβ) metabolism. Although loss of presenilin 1 function has been reported to impair lysosomal function and prevent autophagy flux, the detailed mechanism leading to autophagy dysfunction in AD remains to be elucidated. The resemblance between pathological hallmarks of AD and Niemann-Pick Type C disease, including endosome-lysosome abnormalities and impaired autophagy, suggests cholesterol accumulation as a common link. Using a mouse model of AD (APP-PSEN1-SREBF2 mice), expressing chimeric mouse-human amyloid precursor protein with the familial Alzheimer Swedish mutation (APP695swe) and mutant presenilin 1 (PSEN1-dE9), together with a dominant-positive, truncated and active form of SREBF2/SREBP2 (sterol regulatory element binding factor 2), we demonstrated that high brain cholesterol enhanced autophagosome formation, but disrupted its fusion with endosomal-lysosomal vesicles. The combination of these alterations resulted in impaired degradation of Aβ and endogenous MAPT (microtubule associated protein tau), and stimulated autophagy-dependent Aβ secretion. Exacerbated Aβ-induced oxidative stress in APP-PSEN1-SREBF2 mice, due to cholesterol-mediated depletion of mitochondrial glutathione/mGSH, is critical for autophagy induction. In agreement, in vivo mitochondrial GSH recovery with GSH ethyl ester, inhibited autophagosome synthesis by preventing the oxidative inhibition of ATG4B deconjugation activity exerted by Aβ. Moreover, cholesterol-enrichment within the endosomes-lysosomes modified the levels and membrane distribution of RAB7A and SNAP receptors (SNAREs), which affected its fusogenic ability. Accordingly, in vivo treatment with 2-hydroxypropyl-β-cyclodextrin completely rescued these alterations, making it a potential therapeutic tool for AD.
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Affiliation(s)
- Elisabet Barbero-Camps
- a Department of Cell Death and Proliferation , Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) , Barcelona , Spain
| | - Vicente Roca-Agujetas
- a Department of Cell Death and Proliferation , Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) , Barcelona , Spain
| | - Isabel Bartolessis
- a Department of Cell Death and Proliferation , Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) , Barcelona , Spain
| | - Cristina de Dios
- a Department of Cell Death and Proliferation , Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) , Barcelona , Spain.,c Departament de Biomedicina, Facultat de Medicina , Universitat de Barcelona , Barcelona , Spain
| | - Jose C Fernández-Checa
- a Department of Cell Death and Proliferation , Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) , Barcelona , Spain.,d Liver Unit , Hospital Clinic, CIBEREHD , Barcelona , Spain , Research Center for Alcoholic Liver and Pancreatic Diseases , Keck School of Medicine of the University of Southern California , Los Angeles , CA , USA
| | - Montserrat Marí
- a Department of Cell Death and Proliferation , Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) , Barcelona , Spain
| | - Albert Morales
- a Department of Cell Death and Proliferation , Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) , Barcelona , Spain
| | - Tobias Hartmann
- e Experimental Neurology , Saarland University , Homburg/Saar , Germany
| | - Anna Colell
- a Department of Cell Death and Proliferation , Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) , Barcelona , Spain.,b Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain
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23
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Rentero C, Blanco-Muñoz P, Meneses-Salas E, Grewal T, Enrich C. Annexins-Coordinators of Cholesterol Homeostasis in Endocytic Pathways. Int J Mol Sci 2018; 19:E1444. [PMID: 29757220 PMCID: PMC5983649 DOI: 10.3390/ijms19051444] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 02/07/2023] Open
Abstract
The spatiotemporal regulation of calcium (Ca2+) storage in late endosomes (LE) and lysosomes (Lys) is increasingly recognized to influence a variety of membrane trafficking events, including endocytosis, exocytosis, and autophagy. Alterations in Ca2+ homeostasis within the LE/Lys compartment are implicated in human diseases, ranging from lysosomal storage diseases (LSDs) to neurodegeneration and cancer, and they correlate with changes in the membrane binding behaviour of Ca2+-binding proteins. This also includes Annexins (AnxA), which is a family of Ca2+-binding proteins participating in membrane traffic and tethering, microdomain organization, cytoskeleton interactions, Ca2+ signalling, and LE/Lys positioning. Although our knowledge regarding the way Annexins contribute to LE/Lys functions is still incomplete, recruitment of Annexins to LE/Lys is greatly influenced by the availability of Annexin bindings sites, including acidic phospholipids, such as phosphatidylserine (PS) and phosphatidic acid (PA), cholesterol, and phosphatidylinositol (4,5)-bisphosphate (PIP2). Moreover, the cytosolic portion of LE/Lys membrane proteins may also, directly or indirectly, determine the recruitment of Annexins to LE. Strikingly, within LE/Lys, AnxA1, A2, A6, and A8 differentially contribute to cholesterol transport along the endocytic route, in particular, cholesterol transfer between LE and other compartments, positioning Annexins at the centre of major pathways mediating cellular cholesterol homeostasis. Underlying mechanisms include the formation of membrane contact sites (MCS) and intraluminal vesicles (ILV), as well as the modulation of LE-cholesterol transporter activity. In this review, we will summarize the current understanding how Annexins contribute to influence LE/Lys membrane transport and associated functions.
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Affiliation(s)
- Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona. 08036 Barcelona. Spain.
| | - Patricia Blanco-Muñoz
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona. 08036 Barcelona. Spain.
| | - Elsa Meneses-Salas
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona. 08036 Barcelona. Spain.
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia.
| | - Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona. 08036 Barcelona. Spain.
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain.
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24
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Woodman S, Trousdale C, Conover J, Kim K. Yeast membrane lipid imbalance leads to trafficking defects toward the Golgi. Cell Biol Int 2018; 42:890-902. [PMID: 29500884 DOI: 10.1002/cbin.10956] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/24/2018] [Indexed: 12/19/2022]
Abstract
Protein recycling is an essential cellular process involving endocytosis, intracellular trafficking, and exocytosis. In mammalian systems membrane lipids, including cholesterol, sphingolipids, and phospholipids, play a pivotal role in protein recycling. To address this role in budding yeast, Saccharomyces cerevisiae, we utilized GFP-Snc1, a v-SNARE protein serving as a fluorescent marker for faithfully reporting the recycling pathway. Here we demonstrate results that display moderate to significant GFP-Snc1 recycling defects upon overexpression or inactivation of phospholipid, ergosterol, and sphingolipid biosynthesis enzymes, indicating that the homeostasis of membrane lipid levels is prerequisite for proper protein recycling. By using a truncated version of GFP-Snc1 that cannot be recycled from the plasma membrane, we determined that abnormalities in Snc1 localization in membrane lipid overexpression or underexpression mutants are not due to defects in the synthetic/secretory pathway, but rather in the intracellular trafficking pathway. We found that membrane lipid imbalance resulted in an accumulation of the late endosome marker Vps10-GFP, indicating trafficking from the endosomes to the Golgi may be being hindered, preventing recycling to the plasma membrane. To elucidate the possible mechanism for this trafficking hindrance, we stained the actin cytoskeleton, then quantified the percentage of cells with visible actin cables. Compared to wild-type cells, membrane lipid mutant cells exhibited lower levels of actin cables, indicating the actin cytoskeleton is disrupted upon membrane lipid imbalance. Taken together, our results show that impairment of proper recycling may be due to disruption of the actin cytoskeleton, which causes trafficking hindrance between the endosomes and Golgi.
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Affiliation(s)
- Sara Woodman
- Missouri State University, 901 S National Ave., Springfield, Missouri
| | - Christopher Trousdale
- Missouri State University, 901 S National Ave., Springfield, Missouri.,Washington University in St. Louis, 1 Brookings Dr., St. Louis, Missouri
| | - Justin Conover
- Missouri State University, 901 S National Ave., Springfield, Missouri.,Iowa State University, Ames, Iowa
| | - Kyoungtae Kim
- Missouri State University, 901 S National Ave., Springfield, Missouri.,Iowa State University, Ames, Iowa
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25
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Cairns R, Alvarez-Guaita A, Martínez-Saludes I, Wason SJ, Hanh J, Nagarajan SR, Hosseini-Beheshti E, Monastyrskaya K, Hoy AJ, Buechler C, Enrich C, Rentero C, Grewal T. Role of hepatic Annexin A6 in fatty acid-induced lipid droplet formation. Exp Cell Res 2017; 358:397-410. [PMID: 28712927 DOI: 10.1016/j.yexcr.2017.07.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/07/2017] [Accepted: 07/12/2017] [Indexed: 01/17/2023]
Abstract
Annexin A6 (AnxA6) has been implicated in the regulation of endo-/exocytic pathways, cholesterol transport, and the formation of multifactorial signaling complexes in many different cell types. More recently, AnxA6 has also been linked to triglyceride storage in adipocytes. Here we investigated the potential role of AnxA6 in fatty acid (FA) - induced lipid droplet (LD) formation in hepatocytes. AnxA6 was associated with LD from rat liver and HuH7 hepatocytes. In oleic acid (OA) -loaded HuH7 cells, substantial amounts of AnxA6 bound to LD in a Ca2+-independent manner. Remarkably, stable or transient AnxA6 overexpression in HuH7 cells led to elevated LD numbers/size and neutral lipid staining under control conditions as well as after OA loading compared to controls. In contrast, overexpression of AnxA1, AnxA2 and AnxA8 did not impact on OA-induced lipid accumulation. On the other hand, incubation of AnxA6-depleted HuH7 cells or primary hepatocytes from AnxA6 KO-mice with OA led to reduced FA accumulation and LD numbers. Furthermore, morphological analysis of liver sections from A6-KO mice revealed significantly lower LD numbers compared to wildtype animals. Interestingly, pharmacological inhibition of cytoplasmic phospholipase A2α (cPLA2α)-dependent LD formation was ineffective in AnxA6-depleted HuH7 cells. We conclude that cPLA2α-dependent pathways contribute to the novel regulatory role of hepatic AnxA6 in LD formation.
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Affiliation(s)
- Rose Cairns
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Anna Alvarez-Guaita
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Inés Martínez-Saludes
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Sundeep J Wason
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Jacky Hanh
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Shilpa R Nagarajan
- Discipline of Physiology, School of Medical Science & Bosch Institute; Sydney Medical School; Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia
| | - Elham Hosseini-Beheshti
- Discipline of Physiology, School of Medical Science & Bosch Institute; Sydney Medical School; Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia
| | - Katia Monastyrskaya
- Urology Research Laboratory, Department Clinical Research, University of Bern, 3010 Bern, Switzerland
| | - Andrew J Hoy
- Discipline of Physiology, School of Medical Science & Bosch Institute; Sydney Medical School; Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia
| | - Christa Buechler
- Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany
| | - Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, 08036 Barcelona, Spain.
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia.
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Chang TY, Yamauchi Y, Hasan MT, Chang C. Cellular cholesterol homeostasis and Alzheimer's disease. J Lipid Res 2017; 58:2239-2254. [PMID: 28298292 DOI: 10.1194/jlr.r075630] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/14/2017] [Indexed: 01/12/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia in older adults. Currently, there is no cure for AD. The hallmark of AD is the accumulation of extracellular amyloid plaques composed of amyloid-β (Aβ) peptides (especially Aβ1-42) and neurofibrillary tangles, composed of hyperphosphorylated tau and accompanied by chronic neuroinflammation. Aβ peptides are derived from the amyloid precursor protein (APP). The oligomeric form of Aβ peptides is probably the most neurotoxic species; its accumulation eventually forms the insoluble and aggregated amyloid plaques. ApoE is the major apolipoprotein of the lipoprotein(s) present in the CNS. ApoE has three alleles, of which the Apoe4 allele constitutes the major risk factor for late-onset AD. Here we describe the complex relationship between ApoE4, oligomeric Aβ peptides, and cholesterol homeostasis. The review consists of four parts: 1) key elements involved in cellular cholesterol metabolism and regulation; 2) key elements involved in intracellular cholesterol trafficking; 3) links between ApoE4, Aβ peptides, and disturbance of cholesterol homeostasis in the CNS; 4) potential lipid-based therapeutic targets to treat AD. At the end, we recommend several research topics that we believe would help in better understanding the connection between cholesterol and AD for further investigations.
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Affiliation(s)
- Ta-Yuan Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Yoshio Yamauchi
- Nutri-Life Science Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Mazahir T Hasan
- Laboratory of Memory Circuits, Achucarro Basque Center for Neuroscience, Zamudio, Spain
| | - Catherine Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH
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Kuzu OF, Toprak M, Noory MA, Robertson GP. Effect of lysosomotropic molecules on cellular homeostasis. Pharmacol Res 2017; 117:177-184. [DOI: 10.1016/j.phrs.2016.12.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 12/13/2016] [Indexed: 01/01/2023]
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Grewal T, Hoque M, Conway JRW, Reverter M, Wahba M, Beevi SS, Timpson P, Enrich C, Rentero C. Annexin A6-A multifunctional scaffold in cell motility. Cell Adh Migr 2017; 11:288-304. [PMID: 28060548 DOI: 10.1080/19336918.2016.1268318] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Annexin A6 (AnxA6) belongs to a highly conserved protein family characterized by their calcium (Ca2+)-dependent binding to phospholipids. Over the years, immunohistochemistry, subcellular fractionations, and live cell microscopy established that AnxA6 is predominantly found at the plasma membrane and endosomal compartments. In these locations, AnxA6 acts as a multifunctional scaffold protein, recruiting signaling proteins, modulating cholesterol and membrane transport and influencing actin dynamics. These activities enable AnxA6 to contribute to the formation of multifactorial protein complexes and membrane domains relevant in signal transduction, cholesterol homeostasis and endo-/exocytic membrane transport. Hence, AnxA6 has been implicated in many biological processes, including cell proliferation, survival, differentiation, inflammation, but also membrane repair and viral infection. More recently, we and others identified roles for AnxA6 in cancer cell migration and invasion. This review will discuss how the multiple scaffold functions may enable AnxA6 to modulate migratory cell behavior in health and disease.
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Affiliation(s)
- Thomas Grewal
- a Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - Monira Hoque
- a Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - James R W Conway
- b The Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, St Vincent's Clinical School, Faculty of Medicine , University of New South Wales , Sydney , NSW , Australia
| | - Meritxell Reverter
- c Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina , Universitat de Barcelona , Barcelona , Spain
| | - Mohamed Wahba
- a Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - Syed S Beevi
- a Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - Paul Timpson
- b The Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, St Vincent's Clinical School, Faculty of Medicine , University of New South Wales , Sydney , NSW , Australia
| | - Carlos Enrich
- c Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina , Universitat de Barcelona , Barcelona , Spain
| | - Carles Rentero
- c Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina , Universitat de Barcelona , Barcelona , Spain
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Krautbauer S, Haberl EM, Eisinger K, Pohl R, Rein-Fischboeck L, Rentero C, Alvarez-Guaita A, Enrich C, Grewal T, Buechler C, Neumeier M. Annexin A6 regulates adipocyte lipid storage and adiponectin release. Mol Cell Endocrinol 2017; 439:419-430. [PMID: 27702590 DOI: 10.1016/j.mce.2016.09.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 09/30/2016] [Accepted: 09/30/2016] [Indexed: 12/28/2022]
Abstract
Lipid storage and adipokine secretion are critical features of adipocytes. Annexin A6 (AnxA6) is a lipid-binding protein regulating secretory pathways and its role in adiponectin release was examined. The siRNA-mediated AnxA6 knock-down in 3T3-L1 preadipocytes impaired proliferation, and differentiation of AnxA6-depleted cells to mature adipocytes was associated with higher soluble adiponectin and increased triglyceride storage. The latter was partly attributed to reduced lipolysis. Accordingly, AnxA6 overexpression in 3T3-L1 adipocytes lowered cellular triglycerides and adiponectin secretion. Indeed, serum adiponectin was increased in AnxA6 deficient mice. Expression analysis identified AnxA6 protein to be more abundant in intra-abdominal compared to subcutaneous adipose tissues of mice and men. AnxA6 protein levels increased in white adipose tissues of obese mice and here, levels were highest in subcutaneous fat. AnxA6 protein in adipocytes was upregulated by oxidative stress which might trigger AnxA6 induction in adipose tissues and contribute to impaired fat storage and adiponectin release.
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Affiliation(s)
- Sabrina Krautbauer
- Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany
| | - Elisabeth M Haberl
- Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany
| | - Kristina Eisinger
- Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany
| | - Rebekka Pohl
- Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany
| | - Lisa Rein-Fischboeck
- Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany
| | - Carles Rentero
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
| | - Anna Alvarez-Guaita
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
| | - Carlos Enrich
- Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, 2006, Australia
| | - Christa Buechler
- Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany.
| | - Markus Neumeier
- Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany
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Elgner F, Ren H, Medvedev R, Ploen D, Himmelsbach K, Boller K, Hildt E. The Intracellular Cholesterol Transport Inhibitor U18666A Inhibits the Exosome-Dependent Release of Mature Hepatitis C Virus. J Virol 2016; 90:11181-11196. [PMID: 27707921 PMCID: PMC5126375 DOI: 10.1128/jvi.01053-16] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/28/2016] [Indexed: 12/18/2022] Open
Abstract
Hepatitis C virus (HCV) particles are described as lipoviroparticles which are released similarly to very-low-density lipoproteins (VLDLs). However, the release mechanism is still poorly understood; the canonical endoplasmic reticulum-Golgi intermediate compartment (ERGIC) pathway as well as endosome-dependent release has been proposed. Recently, the role of exosomes in the transmission of HCV has been reported. Only a minor fraction of the de novo-synthesized lipoviroparticles is released by the infected cell. To investigate the relevance of multivesicular bodies (MVBs) for viral morphogenesis and release, the MVB inhibitor U18666A was used. Intracellular trafficking was analyzed by confocal microscopy and electron microscopy. Moreover, an mCherry-tagged HCV variant was used. Conditions were established that enable U18666A-dependent inhibition of MVBs without affecting viral replication. Under these conditions, significant inhibition of the HCV release was observed. The assembly of viral particles is not affected. In U18666A-treated cells, intact infectious viral particles accumulate in CD63-positive exosomal structures and large dysfunctional lysosomal structures (multilamellar bodies). These retained particles possess a lower density, reflecting a misloading with lipids. Our data indicate that at least a fraction of HCV particles leaves the cell via the endosomal pathway. Endosomes facilitate the sorting of HCV particles for release or degradation. IMPORTANCE There are still a variety of open questions regarding morphogenesis and release of hepatitis C virus. The HCV-infected cell produces significant more viral particles that are released, raising the question about the fate of the nonreleased particles. Moreover, the relevance of the endosomal pathway for the release of HCV is under debate. Use of the MVB (multivesicular body) inhibitor U18666A enabled a detailed analysis of the impact of MVBs for viral morphogenesis and release. It was revealed that infectious, fully assembled HCV particles are either MVB-dependently released or intracellularly degraded by the lysosome. Our data indicate that at least a fraction of HCV particles leaves the cell via the endosomal pathway independent from the constitutive secretory pathway. Our study describes a so-far-unprecedented cross talk between two pathways regulating on the one hand the release of infectious viral particles and on the other hand the intracellular degradation of nonreleased particles.
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Affiliation(s)
- Fabian Elgner
- Paul-Ehrlich-Institut, Department of Virology, Langen, Germany
| | - Huimei Ren
- Paul-Ehrlich-Institut, Department of Virology, Langen, Germany
| | - Regina Medvedev
- Paul-Ehrlich-Institut, Department of Virology, Langen, Germany
| | - Daniela Ploen
- Paul-Ehrlich-Institut, Department of Virology, Langen, Germany
| | | | - Klaus Boller
- Paul-Ehrlich-Institut, Department of Virology, Langen, Germany
| | - Eberhard Hildt
- Paul-Ehrlich-Institut, Department of Virology, Langen, Germany
- Deutsches Zentrum für Infektionsforschung, Braunschweig, Germany
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31
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Enrich C, Rentero C, Grewal T. Annexin A6 in the liver: From the endocytic compartment to cellular physiology. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:933-946. [PMID: 27984093 DOI: 10.1016/j.bbamcr.2016.10.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 12/15/2022]
Abstract
Annexin A6 (AnxA6) belongs to the conserved annexin family - a group of Ca2+-dependent membrane binding proteins. AnxA6 is the largest of all annexins and highly expressed in smooth muscle, hepatocytes, endothelial cells and cardiomyocytes. Upon activation, AnxA6 binds to negatively charged phospholipids in a wide range of intracellular localizations, in particular the plasma membrane, late endosomes/pre-lysosomes, but also synaptic vesicles and sarcolemma. In these cellular sites, AnxA6 is believed to contribute to the organization of membrane microdomains, such as cholesterol-rich lipid rafts and confer multiple regulatory functions, ranging from vesicle fusion, endocytosis and exocytosis to programmed cell death and muscle contraction. Growing evidence supports that Ca2+ and Ca2+-binding proteins control endocytosis and autophagy. Their regulatory role seems to operate at the level of the signalling pathways that initiate autophagy or at later stages, when autophagosomes fuse with endolysosomal compartments. The convergence of the autophagic and endocytic vesicles to lysosomes shares several features that depend on Ca2+ originating from lysosomes/late endosomes and seems to depend on proteins that are subsequently activated by this cation. However, the involvement of Ca2+ and its effector proteins in these autophagic and endocytic stages still remains poorly understood. Although AnxA6 makes up almost 0.25% of total protein in the liver, little is known about its function in hepatocytes. Within the endocytic route, we identified AnxA6 in endosomes and autophagosomes of hepatocytes. Hence, AnxA6 and possibly other annexins might represent new Ca2+ effectors that regulate converging steps of autophagy and endocytic trafficking in hepatocytes. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cellular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain.
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cellular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Thomas Grewal
- Faculty of Pharmacy A15, University of Sydney, Sydney, NSW 2006, Australia
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32
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Annexin A6 regulates interleukin-2-mediated T-cell proliferation. Immunol Cell Biol 2016; 94:543-53. [PMID: 26853809 DOI: 10.1038/icb.2016.15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 12/10/2015] [Accepted: 01/10/2016] [Indexed: 02/06/2023]
Abstract
Annexin A6 (AnxA6) has been implicated in cell signalling by contributing to the organisation of the plasma membrane. Here we examined whether AnxA6 regulates signalling and proliferation in T cells. We used a contact hypersensitivity model to immune challenge wild-type (WT) and AnxA6(-/-) mice and found that the in vivo proliferation of CD4(+) T cells, but not CD8(+) T cells, was impaired in AnxA6(-/-) relative to WT mice. However, T-cell migration and signalling through the T-cell receptor ex vivo was similar between T cells isolated from AnxA6(-/-) and WT mice. In contrast, interleukin-2 (IL-2) signalling was reduced in AnxA6(-/-) compared with WT T cells. Further, AnxA6-deficient T cells had reduced membrane order and cholesterol levels. Taken together, our data suggest that AnxA6 regulates IL-2 homeostasis and sensitivity in T cells by sustaining a lipid raft-like membrane environment.
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33
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García-Melero A, Reverter M, Hoque M, Meneses-Salas E, Koese M, Conway JRW, Johnsen CH, Alvarez-Guaita A, Morales-Paytuvi F, Elmaghrabi YA, Pol A, Tebar F, Murray RZ, Timpson P, Enrich C, Grewal T, Rentero C. Annexin A6 and Late Endosomal Cholesterol Modulate Integrin Recycling and Cell Migration. J Biol Chem 2015; 291:1320-35. [PMID: 26578516 DOI: 10.1074/jbc.m115.683557] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 01/01/2023] Open
Abstract
Annexins are a family of proteins that bind to phospholipids in a calcium-dependent manner. Earlier studies implicated annexin A6 (AnxA6) to inhibit secretion and participate in the organization of the extracellular matrix. We recently showed that elevated AnxA6 levels significantly reduced secretion of the extracellular matrix protein fibronectin (FN). Because FN is directly linked to the ability of cells to migrate, this prompted us to investigate the role of AnxA6 in cell migration. Up-regulation of AnxA6 in several cell models was associated with reduced cell migration in wound healing, individual cell tracking and three-dimensional migration/invasion assays. The reduced ability of AnxA6-expressing cells to migrate was associated with decreased cell surface expression of αVβ3 and α5β1 integrins, both FN receptors. Mechanistically, we found that elevated AnxA6 levels interfered with syntaxin-6 (Stx6)-dependent recycling of integrins to the cell surface. AnxA6 overexpression caused mislocalization and accumulation of Stx6 and integrins in recycling endosomes, whereas siRNA-mediated AnxA6 knockdown did not modify the trafficking of integrins. Given our recent findings that inhibition of cholesterol export from late endosomes (LEs) inhibits Stx6-dependent integrin recycling and that elevated AnxA6 levels cause LE cholesterol accumulation, we propose that AnxA6 and blockage of LE cholesterol transport are critical for endosomal function required for Stx6-mediated recycling of integrins in cell migration.
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Affiliation(s)
- Ana García-Melero
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Meritxell Reverter
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Monira Hoque
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Elsa Meneses-Salas
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Meryem Koese
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales 2006, Australia
| | - James R W Conway
- Garvan Institute of Medical Research and Kinghorn Cancer Centre, Cancer Research Program, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Camilla H Johnsen
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Anna Alvarez-Guaita
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Frederic Morales-Paytuvi
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Yasmin A Elmaghrabi
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Albert Pol
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain, and
| | - Francesc Tebar
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain, and
| | - Rachael Z Murray
- Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland 4095, Australia
| | - Paul Timpson
- Garvan Institute of Medical Research and Kinghorn Cancer Centre, Cancer Research Program, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Carlos Enrich
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain, and
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales 2006, Australia,
| | - Carles Rentero
- From the Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain, and
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34
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Hoque M, Rentero C, Conway JR, Murray RZ, Timpson P, Enrich C, Grewal T. The cross-talk of LDL-cholesterol with cell motility: insights from the Niemann Pick Type C1 mutation and altered integrin trafficking. Cell Adh Migr 2015; 9:384-91. [PMID: 26366834 DOI: 10.1080/19336918.2015.1019996] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cholesterol is considered indispensible for the recruitment and functioning of integrins in focal adhesions for cell migration. However, the physiological cholesterol pools that control integrin trafficking and focal adhesion assembly remain unclear. Using Niemann Pick Type C1 (NPC) mutant cells, which accumulate Low Density lipoprotein (LDL)-derived cholesterol in late endosomes (LE), several recent studies indicate that LDL-cholesterol has multiple roles in regulating focal adhesion dynamics. Firstly, targeting of endocytosed LDL-cholesterol from LE to focal adhesions controls their formation at the leading edge of migrating cells. Other newly emerging literature suggests that this may be coupled to vesicular transport of integrins, Src kinase and metalloproteases from the LE compartment to focal adhesions. Secondly, our recent work identified LDL-cholesterol as a key factor that determines the distribution and ability of several Soluble NSF Attachment Protein (SNAP) Receptor (SNARE) proteins, key players in vesicle transport, to control integrin trafficking to the cell surface and extracellular matrix (ECM) secretion. Collectively, dietary, genetic and pathological changes in cholesterol metabolism may link with efficiency and speed of integrin and ECM cell surface delivery in metastatic cancer cells. This commentary will summarize how direct and indirect pathways enable LDL-cholesterol to modulate cell motility.
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Affiliation(s)
- Monira Hoque
- a Faculty of Pharmacy; University of Sydney ; Sydney , Australia
| | - Carles Rentero
- b Departament de Biologia Cellular ; Immunologia i Neurociències; Centre de Recerca Biomèdica CELLEX; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Facultat de Medicina; Universitat de Barcelona ; Barcelona , Spain
| | - James R Conway
- c Cancer Research Program; The Kinghorn Cancer Center; Garvan Institute of Medical Research ; Darlinghurst , Australia
| | - Rachael Z Murray
- d Tissue Repair and Regeneration Program; Institute of Health and Biomedical Innovation; Queensland University of Technology ; Brisbane , Australia
| | - Paul Timpson
- c Cancer Research Program; The Kinghorn Cancer Center; Garvan Institute of Medical Research ; Darlinghurst , Australia
| | - Carlos Enrich
- b Departament de Biologia Cellular ; Immunologia i Neurociències; Centre de Recerca Biomèdica CELLEX; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Facultat de Medicina; Universitat de Barcelona ; Barcelona , Spain
| | - Thomas Grewal
- a Faculty of Pharmacy; University of Sydney ; Sydney , Australia
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35
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Gordon VD, O'Halloran TJ, Shindell O. Membrane adhesion and the formation of heterogeneities: biology, biophysics, and biotechnology. Phys Chem Chem Phys 2015; 17:15522-33. [PMID: 25866854 PMCID: PMC4465551 DOI: 10.1039/c4cp05876c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Membrane adhesion is essential to many vital biological processes. Sites of membrane adhesion are often associated with heterogeneities in the lipid and protein composition of the membrane. These heterogeneities are thought to play functional roles by facilitating interactions between proteins. However, the causal links between membrane adhesion and membrane heterogeneities are not known. Here we survey the state of the field and indicate what we think are understudied areas ripe for development.
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Affiliation(s)
- V D Gordon
- The University of Texas at Austin, Department of Physics and Center for Nonlinear Dynamics, 2515 Speedway, Stop C1610, Austin, Texas 78712-1199, USA.
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36
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Enrich C, Rentero C, Hierro A, Grewal T. Role of cholesterol in SNARE-mediated trafficking on intracellular membranes. J Cell Sci 2015; 128:1071-81. [PMID: 25653390 DOI: 10.1242/jcs.164459] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The cell surface delivery of extracellular matrix (ECM) and integrins is fundamental for cell migration in wound healing and during cancer cell metastasis. This process is not only driven by several soluble NSF attachment protein (SNAP) receptor (SNARE) proteins, which are key players in vesicle transport at the cell surface and intracellular compartments, but is also tightly modulated by cholesterol. Cholesterol-sensitive SNAREs at the cell surface are relatively well characterized, but it is less well understood how altered cholesterol levels in intracellular compartments impact on SNARE localization and function. Recent insights from structural biology, protein chemistry and cell microscopy have suggested that a subset of the SNAREs engaged in exocytic and retrograde pathways dynamically 'sense' cholesterol levels in the Golgi and endosomal membranes. Hence, the transport routes that modulate cellular cholesterol distribution appear to trigger not only a change in the location and functioning of SNAREs at the cell surface but also in endomembranes. In this Commentary, we will discuss how disrupted cholesterol transport through the Golgi and endosomal compartments ultimately controls SNARE-mediated delivery of ECM and integrins to the cell surface and, consequently, cell migration.
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Affiliation(s)
- Carlos Enrich
- Departament de Biologia Cellular, Immunologia i Neurociències, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Facultat de Medicina, Universitat de Barcelona, 08036-Barcelona, Spain
| | - Carles Rentero
- Departament de Biologia Cellular, Immunologia i Neurociències, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS). Facultat de Medicina, Universitat de Barcelona, 08036-Barcelona, Spain
| | - Aitor Hierro
- Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, 48160 Derio; IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
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Alvarez-Guaita A, Vilà de Muga S, Owen DM, Williamson D, Magenau A, García-Melero A, Reverter M, Hoque M, Cairns R, Cornely R, Tebar F, Grewal T, Gaus K, Ayala-Sanmartín J, Enrich C, Rentero C. Evidence for annexin A6-dependent plasma membrane remodelling of lipid domains. Br J Pharmacol 2015; 172:1677-90. [PMID: 25409976 DOI: 10.1111/bph.13022] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 11/11/2014] [Accepted: 11/14/2014] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Annexin A6 (AnxA6) is a calcium-dependent phospholipid-binding protein that can be recruited to the plasma membrane to function as a scaffolding protein to regulate signal complex formation, endo- and exocytic pathways as well as distribution of cellular cholesterol. Here, we have investigated how AnxA6 influences the membrane order. EXPERIMENTAL APPROACH We used Laurdan and di-4-ANEPPDHQ staining in (i) artificial membranes; (ii) live cells to investigate membrane packing and ordered lipid phases; and (iii) a super-resolution imaging (photoactivated localization microscopy, PALM) and Ripley's K second-order point pattern analysis approach to assess how AnxA6 regulates plasma membrane order domains and protein clustering. KEY RESULTS In artificial membranes, purified AnxA6 induced a global increase in membrane order. However, confocal microscopy using di-4-ANEPPDHQ in live cells showed that cells expressing AnxA6, which reduces plasma membrane cholesterol levels and modifies the actin cytoskeleton meshwork, displayed a decrease in membrane order (∼15 and 30% in A431 and MEF cells respectively). PALM data from Lck10 and Src15 membrane raft/non-raft markers revealed that AnxA6 expression induced clustering of both raft and non-raft markers. Altered clustering of Lck10 and Src15 in cells expressing AnxA6 was also observed after cholesterol extraction with methyl-β-cyclodextrin or actin cytoskeleton disruption with latrunculin B. CONCLUSIONS AND IMPLICATIONS AnxA6-induced plasma membrane remodelling indicated that elevated AnxA6 expression decreased membrane order through the regulation of cellular cholesterol homeostasis and the actin cytoskeleton. This study provides the first evidence from live cells that support current models of annexins as membrane organizers.
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Affiliation(s)
- Anna Alvarez-Guaita
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
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Hoque M, Rentero C, Cairns R, Tebar F, Enrich C, Grewal T. Annexins — Scaffolds modulating PKC localization and signaling. Cell Signal 2014; 26:1213-25. [DOI: 10.1016/j.cellsig.2014.02.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 02/22/2014] [Indexed: 12/15/2022]
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39
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Fletcher R, Gribben C, Ma X, Burchfield JG, Thomas KC, Krycer JR, James DE, Fazakerley DJ. The role of the Niemann-Pick disease, type C1 protein in adipocyte insulin action. PLoS One 2014; 9:e95598. [PMID: 24752197 PMCID: PMC3994084 DOI: 10.1371/journal.pone.0095598] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 03/28/2014] [Indexed: 12/12/2022] Open
Abstract
The Niemann-Pick disease, type C1 (NPC1) gene encodes a transmembrane protein involved in cholesterol efflux from the lysosome. SNPs within NPC1 have been associated with obesity and type 2 diabetes, and mice heterozygous or null for NPC1 are insulin resistant. However, the molecular mechanism underpinning this association is currently undefined. This study aimed to investigate the effects of inhibiting NPC1 function on insulin action in adipocytes. Both pharmacological and genetic inhibition of NPC1 impaired insulin action. This impairment was evident at the level of insulin signalling and insulin-mediated glucose transport in the short term and decreased GLUT4 expression due to reduced liver X receptor (LXR) transcriptional activity in the long-term. These data show that cholesterol homeostasis through NPC1 plays a crucial role in maintaining insulin action at multiple levels in adipocytes.
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Affiliation(s)
- Rachael Fletcher
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Christopher Gribben
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Xuiquan Ma
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - James G. Burchfield
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Kristen C. Thomas
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - James R. Krycer
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - David E. James
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- Charles Perkins Centre, School of Molecular Bioscience, The University of Sydney, Sydney, Australia
| | - Daniel J. Fazakerley
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- * E-mail:
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40
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Reverter M, Rentero C, Garcia-Melero A, Hoque M, Vilà de Muga S, Alvarez-Guaita A, Conway JRW, Wood P, Cairns R, Lykopoulou L, Grinberg D, Vilageliu L, Bosch M, Heeren J, Blasi J, Timpson P, Pol A, Tebar F, Murray RZ, Grewal T, Enrich C. Cholesterol regulates Syntaxin 6 trafficking at trans-Golgi network endosomal boundaries. Cell Rep 2014; 7:883-97. [PMID: 24746815 DOI: 10.1016/j.celrep.2014.03.043] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 12/30/2013] [Accepted: 03/17/2014] [Indexed: 12/27/2022] Open
Abstract
Inhibition of cholesterol export from late endosomes causes cellular cholesterol imbalance, including cholesterol depletion in the trans-Golgi network (TGN). Here, using Chinese hamster ovary (CHO) Niemann-Pick type C1 (NPC1) mutant cell lines and human NPC1 mutant fibroblasts, we show that altered cholesterol levels at the TGN/endosome boundaries trigger Syntaxin 6 (Stx6) accumulation into VAMP3, transferrin, and Rab11-positive recycling endosomes (REs). This increases Stx6/VAMP3 interaction and interferes with the recycling of αVβ3 and α5β1 integrins and cell migration, possibly in a Stx6-dependent manner. In NPC1 mutant cells, restoration of cholesterol levels in the TGN, but not inhibition of VAMP3, restores the steady-state localization of Stx6 in the TGN. Furthermore, elevation of RE cholesterol is associated with increased amounts of Stx6 in RE. Hence, the fine-tuning of cholesterol levels at the TGN-RE boundaries together with a subset of cholesterol-sensitive SNARE proteins may play a regulatory role in cell migration and invasion.
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Affiliation(s)
- Meritxell Reverter
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Carles Rentero
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Ana Garcia-Melero
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Monira Hoque
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Sandra Vilà de Muga
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Anna Alvarez-Guaita
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - James R W Conway
- Garvan Institute of Medical Research and Kinghorn Cancer Centre, Cancer Research Program, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Peta Wood
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Rose Cairns
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
| | - Lilia Lykopoulou
- First Department of Pediatrics, University of Athens, Aghia Sofia Children's Hospital, 11527 Athens, Greece
| | - Daniel Grinberg
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, CIBERER, IBUB, 08028 Barcelona, Spain
| | - Lluïsa Vilageliu
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, CIBERER, IBUB, 08028 Barcelona, Spain
| | - Marta Bosch
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Joerg Heeren
- Department of Biochemistry and Molecular Biology II. Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Juan Blasi
- Department of Pathology and Experimental Therapeutics, IDIBELL-University of Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain
| | - Paul Timpson
- Garvan Institute of Medical Research and Kinghorn Cancer Centre, Cancer Research Program, St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW 2010, Australia
| | - Albert Pol
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avaçats (ICREA), 08010 Barcelona, Spain
| | - Francesc Tebar
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Rachael Z Murray
- Tissue Repair and Regeneration Program, Institute of Health and Biomedical, Innovation, Queensland University of Technology, Brisbane, QLD 4095, Australia
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia.
| | - Carlos Enrich
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain; Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain.
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Abstract
Influenza is caused by influenza A virus (IAV), an enveloped, negative-stranded RNA virus that derives its envelope lipids from the host cell plasma membrane. Here, we examined the functional role of cellular cholesterol in the IAV infection cycle. We show that shifting of cellular cholesterol pools via the Ca2+-regulated membrane-binding protein annexin A6 (AnxA6) affects the infectivity of progeny virus particles. Elevated levels of cellular AnxA6, which decrease plasma membrane and increase late endosomal cholesterol levels, impaired IAV replication and propagation, whereas RNA interference-mediated AnxA6 ablation increased viral progeny titers. Pharmacological accumulation of late endosomal cholesterol also diminished IAV virus propagation. Decreased IAV replication caused by upregulated AnxA6 expression could be restored either by exogenous replenishment of host cell cholesterol or by ectopic expression of the late endosomal cholesterol transporter Niemann-Pick C1 (NPC1). Virus released from AnxA6-overexpressing cells displayed significantly reduced cholesterol levels. Our results show that IAV replication depends on maintenance of the cellular cholesterol balance and identify AnxA6 as a critical factor in linking IAV to cellular cholesterol homeostasis. Influenza A virus (IAV) is a major public health concern, and yet, major host-pathogen interactions regulating IAV replication still remain poorly understood. It is known that host cell cholesterol is a critical factor in the influenza virus life cycle. The viral envelope is derived from the host cell membrane during the process of budding and, hence, equips the virus with a special lipid-protein mixture which is high in cholesterol. However, the influence of host cell cholesterol homeostasis on IAV infection is largely unknown. We show that IAV infection success critically depends on host cell cholesterol distribution. Cholesterol sequestration in the endosomal compartment impairs progeny titer and infectivity and is associated with reduced cholesterol content in the viral envelope.
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42
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Wilson RL, Kraft ML. Quantifying the molar percentages of cholesterol in supported lipid membranes by time-of-flight secondary ion mass spectrometry and multivariate analysis. Anal Chem 2012. [PMID: 23199099 DOI: 10.1021/ac301856z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The uneven cholesterol distribution among organelles and within the plasma membrane is postulated to be critical for proper cellular function. To study how interactions between cholesterol and specific lipid species contribute to the uneven cholesterol distribution between and within cellular membranes, model lipid membranes are frequently employed. Although the cholesterol distributions within membranes can be directly imaged without labels by using time-of-flight secondary ion mass spectrometry (TOF-SIMS), quantifying the cholesterol abundance at specific membrane locations in a label-free manner remains a challenge. Here, partial least-squares regression (PLSR) of TOF-SIMS data is used to quantitatively measure the local molar percentage (mol %) of cholesterol within supported lipid membranes. With the use of TOF-SIMS data from lipid membranes of known composition, a PLSR model was constructed that correlated the spectral variation to the mol % cholesterol in the membrane. The PLSR model was then used to measure the mol % cholesterol in test membranes and to measure cholesterol exchange between vesicles and supported lipid membranes. The accuracy of these measurements was assessed by comparison to the mol % cholesterol measured with conventional assays. By using this TOF-SIMS/PLSR approach to quantify the mol % cholesterol with location specificity, a better understanding of how the regional lipid composition influences cholesterol abundance and exchange in membranes may be obtained.
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Affiliation(s)
- Robert L Wilson
- Department of Chemistry, University of Illinois at Urbana-Champaign, 61801, United States
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43
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Un K, Sakai-Kato K, Oshima Y, Kawanishi T, Okuda H. Intracellular trafficking mechanism, from intracellular uptake to extracellular efflux, for phospholipid/cholesterol liposomes. Biomaterials 2012; 33:8131-41. [DOI: 10.1016/j.biomaterials.2012.07.030] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 07/15/2012] [Indexed: 01/27/2023]
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44
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Koese M, Rentero C, Kota BP, Hoque M, Cairns R, Wood P, Vilà de Muga S, Reverter M, Alvarez-Guaita A, Monastyrskaya K, Hughes WE, Swarbrick A, Tebar F, Daly RJ, Enrich C, Grewal T. Annexin A6 is a scaffold for PKCα to promote EGFR inactivation. Oncogene 2012; 32:2858-72. [PMID: 22797061 DOI: 10.1038/onc.2012.303] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Protein kinase Cα (PKCα) can phosphorylate the epidermal growth factor receptor (EGFR) at threonine 654 (T654) to inhibit EGFR tyrosine phosphorylation (pY-EGFR) and the associated activation of downstream effectors. However, upregulation of PKCα in a large variety of cancers is not associated with EGFR inactivation, and factors determining the potential of PKCα to downregulate EGFR are yet unknown. Here, we show that ectopic expression of annexin A6 (AnxA6), a member of the Ca(2+) and phospholipid-binding annexins, strongly reduces pY-EGFR levels while augmenting EGFR T654 phosphorylation in EGFR overexpressing A431, head and neck and breast cancer cell lines. Reduced EGFR activation in AnxA6 expressing A431 cells is associated with reduced EGFR internalization and degradation. RNA interference (RNAi)-mediated PKCα knockdown in AnxA6 expressing A431 cells reduces T654-EGFR phosphorylation, but restores EGFR tyrosine phosphorylation, clonogenic growth and EGFR degradation. These findings correlate with AnxA6 interacting with EGFR, and elevated AnxA6 levels promoting PKCα membrane association and interaction with EGFR. Stable expression of the cytosolic N-terminal mutant AnxA6(1-175), which cannot promote PKCα membrane recruitment, does not increase T654-EGFR phosphorylation or the association of PKCα with EGFR. AnxA6 overexpression does not inhibit tyrosine phosphorylation of the T654A EGFR mutant, which cannot be phosphorylated by PKCα. Most strikingly, stable plasma membrane anchoring of AnxA6 is sufficient to recruit PKCα even in the absence of EGF or Ca(2+). In summary, AnxA6 is a new PKCα scaffold to promote PKCα-mediated EGFR inactivation through increased membrane targeting of PKCα and EGFR/PKCα complex formation.
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Affiliation(s)
- M Koese
- Faculty of Pharmacy, University of Sydney, Sydney, New South Wales, Australia
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Annexin A1 and A2: roles in retrograde trafficking of Shiga toxin. PLoS One 2012; 7:e40429. [PMID: 22792315 PMCID: PMC3391278 DOI: 10.1371/journal.pone.0040429] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 06/06/2012] [Indexed: 01/05/2023] Open
Abstract
Annexins constitute a family of calcium and membrane binding proteins. As annexin A1 and A2 have previously been linked to various membrane trafficking events, we initiated this study to investigate the role of these annexins in the uptake and intracellular transport of the bacterial Shiga toxin (Stx) and the plant toxin ricin. Once endocytosed, both toxins are retrogradely transported from endosomes to the Golgi apparatus and the endoplasmic reticulum before being targeted to the cytosol where they inhibit protein synthesis. This study was performed to obtain new information both about toxin transport and the function of annexin A1 and annexin A2. Our data show that depletion of annexin A1 or A2 alters the retrograde transport of Stx but not ricin, without affecting toxin binding or internalization. Knockdown of annexin A1 increases Golgi transport of Stx, whereas knockdown of annexin A2 slightly decreases the same transport step. Interestingly, annexin A1 was found in proximity to cytoplasmic phospholipase A2 (cPLA2), and the basal as well as the increased Golgi transport of Stx upon annexin A1 knockdown is dependent on cPLA2 activity. In conclusion, annexin A1 and A2 have different roles in Stx transport to the trans-Golgi network. The most prominent role is played by annexin A1 which normally works as a negative regulator of retrograde transport from the endosomes to the Golgi network, most likely by complex formation and inhibition of cPLA2.
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46
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Bandorowicz-Pikula J, Wos M, Pikula S. Do annexins participate in lipid messenger mediated intracellular signaling? A question revisited. Mol Membr Biol 2012; 29:229-42. [PMID: 22694075 DOI: 10.3109/09687688.2012.693210] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Annexins are physiologically important proteins that play a role in calcium buffering but also influence membrane structure, participate in Ca²⁺-dependent membrane repair events and in remodelling of the cytoskeleton. Thirty years ago several peptides isolated from lung perfusates, peritoneal leukocytes, neutrophiles and renal cells were proven inhibitory to the activity of phospholipase A₂. Those peptides were found to derive from structurally related proteins: annexins AnxA1 and AnxA2. These findings raised the question whether annexins may participate in regulation of the production of lipid second messengers and, therefore, modulate numerous lipid mediated signaling pathways in the cell. Recent advances in the field of annexins made also with the use of knock-out animal models revealed that these proteins are indeed important constituents of specific signaling pathways. In this review we provide evidence supporting the hypothesis that annexins, as membrane-binding proteins and organizers of the membrane lateral heterogeneity, may participate in lipid mediated signaling pathways by affecting the distribution and activity of lipid metabolizing enzymes (most of the reports point to phospholipase A₂) and of protein kinases regulating activity of these enzymes. Moreover, some experimental data suggest that annexins may directly interact with lipid metabolizing enzymes and, in a calcium-dependent or independent manner, with some of their substrates and products. On the basis of these observations, many investigators suggest that annexins are capable of linking Ca²⁺, redox and lipid signaling to coordinate vital cellular responses to the environmental stimuli.
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Affiliation(s)
- Joanna Bandorowicz-Pikula
- Laboratory of Cellular Metabolism, Department of Biochemistry, Nencki Institute of Experimental Biology, PL 02-093 Warsaw, Poland.
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47
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Cai B, Caplan S, Naslavsky N. cPLA2α and EHD1 interact and regulate the vesiculation of cholesterol-rich, GPI-anchored, protein-containing endosomes. Mol Biol Cell 2012; 23:1874-88. [PMID: 22456504 PMCID: PMC3350552 DOI: 10.1091/mbc.e11-10-0881] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
cPLA2 hydrolyzes phospholipids and regulates membrane curvature and/or tubulation. Despite disparate roles for cPLA2 at the Golgi and early endosomes, its function in the regulation of membranes containing GPI-anchored proteins is not known. A role for cPLA2α and EHD1 is identified in the vesiculation of cholesterol-rich, GPI-AP–containing membranes. The lipid modifier phospholipase A2 catalyzes the hydrolysis of phospholipids to inverted-cone–shaped lysophospholipids that contribute to membrane curvature and/or tubulation. Conflicting findings exist regarding the function of cytosolic phospholipase A2 (cPLA2) and its role in membrane regulation at the Golgi and early endosomes. However, no studies addressed the role of cPLA2 in the regulation of cholesterol-rich membranes that contain glycosylphosphatidylinositol-anchored proteins (GPI-APs). Our studies support a role for cPLA2α in the vesiculation of GPI-AP–containing membranes, using endogenous CD59 as a model for GPI-APs. On cPLA2α depletion, CD59-containing endosomes became hypertubular. Moreover, accumulation of lysophospholipids induced by a lysophospholipid acyltransferase inhibitor extensively vesiculated CD59-containing endosomes. However, overexpression of cPLA2α did not increase the endosomal vesiculation, implying a requirement for additional factors. Indeed, depletion of the “pinchase” EHD1, a C-terminal Eps15 homology domain (EHD) ATPase, also induced hypertubulation of CD59-containing endosomes. Furthermore, EHD1 and cPLA2α demonstrated in situ proximity (<40 nm) and interacted in vivo. The results presented here provide evidence that the lipid modifier cPLA2α and EHD1 are involved in the vesiculation of CD59-containing endosomes. We speculate that cPLA2α induces membrane curvature and allows EHD1, possibly in the context of a complex, to sever the curved membranes into vesicles.
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Affiliation(s)
- Bishuang Cai
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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