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Şentürk M, Lin G, Zuo Z, Mao D, Watson E, Mikos AG, Bellen HJ. Ubiquilins regulate autophagic flux through mTOR signalling and lysosomal acidification. Nat Cell Biol 2019; 21:384-396. [PMID: 30804504 PMCID: PMC6534127 DOI: 10.1038/s41556-019-0281-x] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
Abstract
Although the aetiology of amyotrophic lateral sclerosis (ALS) remains poorly understood, impaired proteostasis is a common feature of different forms of ALS. Mutations in genes encoding ubiquilins, UBQLN2 and UBQLN4, cause familial ALS. The role of ubiquilins in proteasomal degradation is well established, but their role in autophagy-lysosomal clearance is poorly defined. Here, we describe a crosstalk between endoplasmic reticulum stress, mTOR signalling and autophagic flux in Drosophila and mammalian cells lacking ubiquilins. We found that loss of ubiquilins leads to endoplasmic reticulum stress, impairs mTORC1 activity, promotes autophagy and causes the demise of neurons. We show that ubiquilin mutants display defective autophagic flux due to reduced lysosome acidification. Ubiquilins are required to maintain proper levels of the V0a/V100 subunit of the vacuolar H+-ATPase and lysosomal pH. Feeding flies acidic nanoparticles alleviates defective autophagic flux in ubiquilin mutants. Hence, our studies reveal a conserved role for ubiquilins as regulators of autophagy by controlling vacuolar H+-ATPase activity and mTOR signalling.
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Affiliation(s)
- Mümine Şentürk
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Guang Lin
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA
| | - Dongxue Mao
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Emma Watson
- Department of Bioengineering, Rice University, Houston, TX, USA
- Medical Scientist Training Program, BCM, Houston, TX, USA
| | - Antonios G Mikos
- Department of Bioengineering, Rice University, Houston, TX, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA.
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA.
- Department of Neuroscience, BCM, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
- Howard Hughes Medical Institute, BCM, Houston, TX, USA.
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52
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Saito E, Kuo R, Pearson RM, Gohel N, Cheung B, King NJC, Miller SD, Shea LD. Designing drug-free biodegradable nanoparticles to modulate inflammatory monocytes and neutrophils for ameliorating inflammation. J Control Release 2019; 300:185-196. [PMID: 30822435 DOI: 10.1016/j.jconrel.2019.02.025] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/12/2022]
Abstract
Inflammation associated with autoimmune diseases and chronic injury is an initiating event that leads to tissue degeneration and dysfunction. Inflammatory monocytes and neutrophils systemically circulate and enter inflamed tissue, and pharmaceutical based targeting of these cells has not substantially improved outcomes and has had side effects. Herein, we investigated the design of drug-free biodegradable nanoparticles, notably without any active pharmaceutical ingredient or targeting ligand, that target circulating inflammatory monocytes and neutrophils in the vasculature to inhibit them from migrating into inflamed tissue. Nanoparticles were formed from 50:50 poly(DL-lactide-co-glycolide) (PLG) with two molecular weights (Low, High) and poly(DL-lactide) (PLA) (termed PLG-L, PLG-H, and PDLA, respectively) and were analyzed for their association with monocytes and neutrophils and their impact on disease course along with immune cell trafficking. For particles injected intravenously for 6 consecutive days to mice with experimental autoimmune encephalomyelitis (EAE), PLG-H particles had significantly lower EAE clinical scores than PBS control, while PLG-L and PDLA particles had modest or negligible effect on EAE onset. In vivo and in vitro data suggests that PLG-H particles had high association with immune cells, with preferential association with blood neutrophils relative to other particles. PLG-H particles restrained immune cells from the central nervous system (CNS), with increased accumulation in the spleen, which was not observed for mice receiving PDLA or control treatments. These results demonstrate that the particle composition influences the association with inflammatory monocytes and neutrophils in the vasculature, with the potential to redirect trafficking and ameliorate inflammation.
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Affiliation(s)
- Eiji Saito
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Robert Kuo
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ryan M Pearson
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201, USA
| | - Nishant Gohel
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brandon Cheung
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicholas J C King
- The Discipline of Pathology, School of Medical Science, Bosch Institute, Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Stephen D Miller
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Chemistry of Life Processes Institute (CLP), Northwestern University, Evanston, IL 60208, USA; The Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL 60611, USA.
| | - Lonnie D Shea
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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53
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Novel Approaches for the Treatment of Alzheimer's and Parkinson's Disease. Int J Mol Sci 2019; 20:ijms20030719. [PMID: 30743990 PMCID: PMC6386829 DOI: 10.3390/ijms20030719] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/18/2019] [Accepted: 02/03/2019] [Indexed: 12/19/2022] Open
Abstract
Neurodegenerative disorders affect around one billion people worldwide. They can arise from a combination of genomic, epigenomic, metabolic, and environmental factors. Aging is the leading risk factor for most chronic illnesses of old age, including Alzheimer’s and Parkinson’s diseases. A progressive neurodegenerative process and neuroinflammation occur, and no current therapies can prevent, slow, or halt disease progression. To date, no novel disease-modifying therapies have been shown to provide significant benefit for patients who suffer from these devastating disorders. Therefore, early diagnosis and the discovery of new targets and novel therapies are of upmost importance. Neurodegenerative diseases, like in other age-related disorders, the progression of pathology begins many years before the onset of symptoms. Many efforts in this field have led to the conclusion that exits some similar events among these diseases that can explain why the aging brain is so vulnerable to suffer neurodegenerative diseases. This article reviews the current knowledge about these diseases by summarizing the most common features of major neurodegenerative disorders, their causes and consequences, and the proposed novel therapeutic approaches.
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54
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Mohammadinejad R, Moosavi MA, Tavakol S, Vardar DÖ, Hosseini A, Rahmati M, Dini L, Hussain S, Mandegary A, Klionsky DJ. Necrotic, apoptotic and autophagic cell fates triggered by nanoparticles. Autophagy 2019; 15:4-33. [PMID: 30160607 PMCID: PMC6287681 DOI: 10.1080/15548627.2018.1509171] [Citation(s) in RCA: 243] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 07/19/2018] [Accepted: 08/03/2018] [Indexed: 12/15/2022] Open
Abstract
Nanomaterials have gained a rapid increase in use in a variety of applications that pertain to many aspects of human life. The majority of these innovations are centered on medical applications and a range of industrial and environmental uses ranging from electronics to environmental remediation. Despite the advantages of NPs, the knowledge of their toxicological behavior and their interactions with the cellular machinery that determines cell fate is extremely limited. This review is an attempt to summarize and increase our understanding of the mechanistic basis of nanomaterial interactions with the cellular machinery that governs cell fate and activity. We review the mechanisms of NP-induced necrosis, apoptosis and autophagy and potential implications of these pathways in nanomaterial-induced outcomes. Abbreviations: Ag, silver; CdTe, cadmium telluride; CNTs, carbon nanotubes; EC, endothelial cell; GFP, green fluorescent protein; GO, graphene oxide; GSH, glutathione; HUVECs, human umbilical vein endothelial cells; NP, nanoparticle; PEI, polyethylenimine; PVP, polyvinylpyrrolidone; QD, quantum dot; ROS, reactive oxygen species; SiO2, silicon dioxide; SPIONs, superparamagnetic iron oxide nanoparticles; SWCNT, single-walled carbon nanotubes; TiO2, titanium dioxide; USPION, ultra-small super paramagnetic iron oxide; ZnO, zinc oxide.
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Affiliation(s)
- Reza Mohammadinejad
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Amin Moosavi
- Department of Molecular Medicine, Institute of Medical Biotechnology, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran
| | - Shima Tavakol
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Deniz Özkan Vardar
- Sungurlu Vocational High School, Health Programs, Hitit University, Corum, Turkey
| | - Asieh Hosseini
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Marveh Rahmati
- Cancer Biology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Salik Hussain
- Department of Physiology, Pharmacology and Neuroscience, West Virginia University, School of Medicine, Morgantown, WV, USA
| | - Ali Mandegary
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
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55
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Prisner L, Witthöft P, Nguyen LVN, Tsangas T, Gefken T, Klaus F, Strelow C, Kipp T, Mews A. Monitoring the death of single BaF3 cells under plasmonic photothermal heating induced by ultrasmall gold nanorods. J Mater Chem B 2019. [DOI: 10.1039/c8tb03135e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Morphological changes and trypan-blue staining are temporally tracked in single cells via optical microscopy after plasmonic photothermal heating.
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Affiliation(s)
- Lisa Prisner
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
| | - Phillip Witthöft
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
| | - Lan Vi Ngoc Nguyen
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
| | - Thomas Tsangas
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
| | - Tobias Gefken
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
| | - Florentine Klaus
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
| | - Christian Strelow
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
| | - Tobias Kipp
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
| | - Alf Mews
- Institute of Physical Chemistry
- University of Hamburg
- D-20146, Hamburg
- Germany
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56
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Quilles Junior JC, Carlos FDRR, Montanari A, Leitão A, Mignone VW, Arruda MA, Turyanska L, Bradshaw TD. Apoferritin encapsulation of cysteine protease inhibitors for cathepsin L inhibition in cancer cells. RSC Adv 2019; 9:36699-36706. [PMID: 35539052 PMCID: PMC9075514 DOI: 10.1039/c9ra07161j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/04/2019] [Indexed: 11/21/2022] Open
Abstract
Cysteine proteases play a key role in tumorigenesis causing protein degradation and promoting invasive tumour growth. Cathepsin L is overexpressed in cancer cells and could provide a specific target for delivery of anticancer agents. We encapsulated novel dipeptidyl nitrile based cysteine protease inhibitors (Neq0551, Neq0554 and Neq0568) into biocompatible apoferritin (AFt) protein nanocages to achieve specific delivery to tumours and pH-induced drug release. AFt-encapsulated Neq0554 demonstrated ∼3-fold enhanced in vitro activity (GI50 = 79 μM) compared to naked agent against MiaPaCa-2 pancreatic carcinoma cells. Selectivity for cancer cells was confirmed by comparing their activity to non-tumourigenic human fibroblasts (GI50 > 200 μM). Transferrin receptor (TfR-1) expression, detected only in lysates prepared from carcinoma cells, may contribute to the cancer-selectivity. The G1 cell cycle arrest caused by AFt-Neq0554 resulting in cytostasis was corroborated by clonogenic assays. Superior and more persistent inhibition of cathepsin L up to 80% was achieved with AFt-encapsulated agent in HCT-116 cells following 6 h exposure to 50 μM agent. The selective anticancer activity of AFt-encapsulated cysteine protease inhibitor Neq0554 reported here warrants further preclinical in vivo evaluation. Novel apoferritin encapsulated cysteine protease inhibitors are developed with enhanced and selective uptake by cancer cells, and sustained pH-induced release of the agent. The persistent inhibition of cathepsin L is demonstrated in vitro.![]()
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Affiliation(s)
- José C. Quilles Junior
- Centre for Biomolecular Sciences
- School of Pharmacy
- University of Nottingham
- UK
- Medicinal Chemistry Group (NEQUIMED)
| | | | - A. Montanari
- Medicinal Chemistry Group (NEQUIMED)
- São Carlos Institute of Chemistry (IQSC)
- University of São Paulo
- Brazil
| | - Andrei Leitão
- Medicinal Chemistry Group (NEQUIMED)
- São Carlos Institute of Chemistry (IQSC)
- University of São Paulo
- Brazil
| | | | | | | | - Tracey D. Bradshaw
- Centre for Biomolecular Sciences
- School of Pharmacy
- University of Nottingham
- UK
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57
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Willmann W, Dringen R. Monitoring of the Cytoskeleton-Dependent Intracellular Trafficking of Fluorescent Iron Oxide Nanoparticles by Nanoparticle Pulse-Chase Experiments in C6 Glioma Cells. Neurochem Res 2018; 43:2055-2071. [PMID: 30196349 DOI: 10.1007/s11064-018-2627-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/21/2018] [Accepted: 08/31/2018] [Indexed: 12/12/2022]
Abstract
Iron oxide nanoparticles (IONPs) are used for various biomedical and therapeutic approaches. To investigate the uptake and the intracellular trafficking of IONPs in neural cells we have performed nanoparticle pulse-chase experiments to visualize the internalization and the fate of fluorescent IONPs in C6 glioma cells and astrocyte cultures. Already a short exposure to IONPs for 10 min at 4 °C (nanoparticle pulse) allowed binding of substantial amounts of nanoparticles to the cells, while internalization of IONPs into the cell was prevented. The uptake of bound IONPs and the intracellular trafficking was started by increasing the temperature to 37 °C (chase period). While hardly any cellular fluorescence nor any iron staining was detectable directly after the nanoparticle pulse, dotted cellular fluorescence and iron patterns appeared already within a few minutes after start of the chase incubation and became intensified in the perinuclear region during further incubation for up to 90 min. Longer chase incubations resulted in separation of the fluorescent coat from the core of the internalized IONPs. Disruption of actin filaments in C6 cells strongly impaired the internalization of IONPs, whereas destabilization of microtubules traped IONP-containing vesicles to the plasma membrane. In conclusion, nanoparticle pulse-chase experiments allowed to synchronize the cellular uptake of fluorescent IONPs and to identify for C6 cells an actin-dependent early and a microtubule-dependent later process in the intracellular trafficking of fluorescent IONPs.
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Affiliation(s)
- Wiebke Willmann
- Center for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, PO. Box 330440, 28334, Bremen, Germany
- Center for Environmental Research and Sustainable Technology, Leobener Strasse, 28359, Bremen, Germany
| | - Ralf Dringen
- Center for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, PO. Box 330440, 28334, Bremen, Germany.
- Center for Environmental Research and Sustainable Technology, Leobener Strasse, 28359, Bremen, Germany.
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58
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Magrì D, Sánchez-Moreno P, Caputo G, Gatto F, Veronesi M, Bardi G, Catelani T, Guarnieri D, Athanassiou A, Pompa PP, Fragouli D. Laser Ablation as a Versatile Tool To Mimic Polyethylene Terephthalate Nanoplastic Pollutants: Characterization and Toxicology Assessment. ACS NANO 2018; 12:7690-7700. [PMID: 29944342 DOI: 10.1021/acsnano.8b01331] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The presence of micro- and nanoplastics in the marine environment is raising strong concerns since they can possibly have a negative impact on human health. In particular, the lack of appropriate methodologies to collect the nanoplastics from water systems imposes the use of engineered model nanoparticles to explore their interactions with biological systems, with results not easily correlated with the real case conditions. In this work, we propose a reliable top-down approach based on laser ablation of polymers to form polyethylene terephthalate (PET) nanoplastics, which mimic real environmental nanopollutants, unlike synthetic samples obtained by colloidal chemistry. PET nanoparticles were carefully characterized in terms of chemical/physical properties and stability in different media. The nanoplastics have a ca. 100 nm average dimension, with significant size and shape heterogeneity, and they present weak acid groups on their surface, similarly to photodegraded PET plastics. Despite no toxic effects emerging by in vitro studies on human Caco-2 intestinal epithelial cells, the formed nanoplastics were largely internalized in endolysosomes, showing intracellular biopersistence and long-term stability in a simulated lysosomal environment. Interestingly, when tested on a model of intestinal epithelium, nano-PET showed high propensity to cross the gut barrier, with unpredictable long-term effects on health and potential transport of dispersed chemicals mediated by the nanopollutants.
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Affiliation(s)
- Davide Magrì
- Smart Materials , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
- Department of Informatics, Bioengineering, Robotics and Systems Engineering , University of Genova , Via All'Opera Pia, 13 , 16145 Genova , Italy
| | - Paola Sánchez-Moreno
- Nanobiointeractions & Nanodiagnostics , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
| | - Gianvito Caputo
- Smart Materials , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
| | - Francesca Gatto
- Nanobiointeractions & Nanodiagnostics , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
- Department of Engineering for Innovation , University of Salento , Via per Monteroni , 73100 Lecce , Italy
| | - Marina Veronesi
- D3-PharmaChemistry , Istituto Italiano di Tecnologia , Via Morego 30 , 16163 Genova , Italy
| | - Giuseppe Bardi
- Nanobiointeractions & Nanodiagnostics , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
| | - Tiziano Catelani
- Electron Microscopy Facility , Istituto Italiano di Tecnologia , Via Morego 30 , 16163 Genova , Italy
| | - Daniela Guarnieri
- Nanobiointeractions & Nanodiagnostics , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
| | - Athanassia Athanassiou
- Smart Materials , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
| | - Pier Paolo Pompa
- Nanobiointeractions & Nanodiagnostics , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
| | - Despina Fragouli
- Smart Materials , Istituto Italiano di Tecnologia , Via Morego, 30 , 16163 Genova , Italy
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59
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Ramachandra Rao S, Pfeffer BA, Más Gómez N, Skelton LA, Keiko U, Sparrow JR, Rowsam AM, Mitchell CH, Fliesler SJ. Compromised phagosome maturation underlies RPE pathology in cell culture and whole animal models of Smith-Lemli-Opitz Syndrome. Autophagy 2018; 14:1796-1817. [PMID: 29979914 PMCID: PMC6135634 DOI: 10.1080/15548627.2018.1490851] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 05/25/2018] [Accepted: 06/11/2018] [Indexed: 12/27/2022] Open
Abstract
Treatment of rats with the cholesterol pathway inhibitor AY9944 produces an animal model of Smith-Lemli-Opitz syndrome (SLOS), an autosomal recessive disease caused by defective cholesterol synthesis. This SLOS rat model undergoes progressive and irreversible degeneration of the neural retina, with associated pathological features of the retinal pigmented epithelium (RPE). Here, we provide further insights into the mechanism involved in the RPE pathology. In the SLOS rat model, markedly increased RPE apical autofluorescence is observed, compared to untreated animals, which correlates with increased levels of A2E and other bisretinoids. Utilizing cultured human induced pluripotent stem cell (iPSC)- derived SLOS RPE cells, we found significantly elevated steady-state levels of 7-dehydrocholesterol (7DHC) and decreased cholesterol levels (key biochemical hallmarks of SLOS). Western blot analysis revealed altered levels of the macroautophagy/autophagy markers MAP1LC3B-II and SQSTM1/p62, and build-up of ubiquitinated proteins. Accumulation of immature autophagosomes was accompanied by inefficient degradation of phagocytized, exogenously supplied retinal rod outer segments (as evidenced by persistence of the C-terminal 1D4 epitope of RHO [rhodopsin]) in SLOS RPE compared to iPSC-derived normal human control. SLOS RPE cells exhibited lysosomal pH levels and CTSD activity within normal physiological limits, thus discounting the involvement of perturbed lysosomal function. Furthermore, 1D4-positive phagosomes that accumulated in the RPE in both pharmacological and genetic rodent models of SLOS failed to fuse with lysosomes. Taken together, these observations suggest that defective phagosome maturation underlies the observed RPE pathology. The potential relevance of these findings to SLOS and the requirement of cholesterol for phagosome maturation are discussed.
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Affiliation(s)
- Sriganesh Ramachandra Rao
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Bruce A. Pfeffer
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Néstor Más Gómez
- Department of Anatomy & Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA
| | - Lara A. Skelton
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Ueda Keiko
- Departments of Ophthalmology (Harkness Eye Institute) and Pathology & Cell Biology, Columbia University, College of Physicians & Surgeons, NY, NY, USA
| | - Janet R. Sparrow
- Departments of Ophthalmology (Harkness Eye Institute) and Pathology & Cell Biology, Columbia University, College of Physicians & Surgeons, NY, NY, USA
| | - Aryn M. Rowsam
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Claire H. Mitchell
- Department of Anatomy & Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA
| | - Steven J. Fliesler
- Departments of Ophthalmology (Ross Eye Institute) and Biochemistry, Jacobs School of Medicine and Biomedical Sciences, SUNY-University at Buffalo, Buffalo, NY, USA
- SUNY Eye Institute, Buffalo, NY, USA
- Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
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60
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Mauthe M, Orhon I, Rocchi C, Zhou X, Luhr M, Hijlkema KJ, Coppes RP, Engedal N, Mari M, Reggiori F. Chloroquine inhibits autophagic flux by decreasing autophagosome-lysosome fusion. Autophagy 2018; 14:1435-1455. [PMID: 29940786 PMCID: PMC6103682 DOI: 10.1080/15548627.2018.1474314] [Citation(s) in RCA: 1263] [Impact Index Per Article: 210.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 02/08/2023] Open
Abstract
Macroautophagy/autophagy is a conserved transport pathway where targeted structures are sequestered by phagophores, which mature into autophagosomes, and then delivered into lysosomes for degradation. Autophagy is involved in the pathophysiology of numerous diseases and its modulation is beneficial for the outcome of numerous specific diseases. Several lysosomal inhibitors such as bafilomycin A1 (BafA1), protease inhibitors and chloroquine (CQ), have been used interchangeably to block autophagy in in vitro experiments assuming that they all primarily block lysosomal degradation. Among them, only CQ and its derivate hydroxychloroquine (HCQ) are FDA-approved drugs and are thus currently the principal compounds used in clinical trials aimed to treat tumors through autophagy inhibition. However, the precise mechanism of how CQ blocks autophagy remains to be firmly demonstrated. In this study, we focus on how CQ inhibits autophagy and directly compare its effects to those of BafA1. We show that CQ mainly inhibits autophagy by impairing autophagosome fusion with lysosomes rather than by affecting the acidity and/or degradative activity of this organelle. Furthermore, CQ induces an autophagy-independent severe disorganization of the Golgi and endo-lysosomal systems, which might contribute to the fusion impairment. Strikingly, HCQ-treated mice also show a Golgi disorganization in kidney and intestinal tissues. Altogether, our data reveal that CQ and HCQ are not bona fide surrogates for other types of late stage lysosomal inhibitors for in vivo experiments. Moreover, the multiple cellular alterations caused by CQ and HCQ call for caution when interpreting results obtained by blocking autophagy with this drug.
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Affiliation(s)
- Mario Mauthe
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Cell Biology, University Medical Center Utrecht, Center for Molecular Medicine, Utrecht, The Netherlands
| | - Idil Orhon
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Cecilia Rocchi
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Xingdong Zhou
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
| | - Morten Luhr
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership for Molecular Medicine, University of Oslo, Oslo, Norway
| | - Kerst-Jan Hijlkema
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Robert P. Coppes
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nikolai Engedal
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership for Molecular Medicine, University of Oslo, Oslo, Norway
| | - Muriel Mari
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Cell Biology, University Medical Center Utrecht, Center for Molecular Medicine, Utrecht, The Netherlands
| | - Fulvio Reggiori
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Cell Biology, University Medical Center Utrecht, Center for Molecular Medicine, Utrecht, The Netherlands
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61
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Bingol B. Autophagy and lysosomal pathways in nervous system disorders. Mol Cell Neurosci 2018; 91:167-208. [PMID: 29729319 DOI: 10.1016/j.mcn.2018.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 04/26/2018] [Accepted: 04/28/2018] [Indexed: 12/12/2022] Open
Abstract
Autophagy is an evolutionarily conserved pathway for delivering cytoplasmic cargo to lysosomes for degradation. In its classically studied form, autophagy is a stress response induced by starvation to recycle building blocks for essential cellular processes. In addition, autophagy maintains basal cellular homeostasis by degrading endogenous substrates such as cytoplasmic proteins, protein aggregates, damaged organelles, as well as exogenous substrates such as bacteria and viruses. Given their important role in homeostasis, autophagy and lysosomal machinery are genetically linked to multiple human disorders such as chronic inflammatory diseases, cardiomyopathies, cancer, and neurodegenerative diseases. Multiple targets within the autophagy and lysosomal pathways offer therapeutic opportunities to benefit patients with these disorders. Here, I will summarize the mechanisms of autophagy pathways, the evidence supporting a pathogenic role for disturbed autophagy and lysosomal degradation in nervous system disorders, and the therapeutic potential of autophagy modulators in the clinic.
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Affiliation(s)
- Baris Bingol
- Genentech, Inc., Department of Neuroscience, 1 DNA Way, South San Francisco 94080, United States.
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62
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Bourquin J, Milosevic A, Hauser D, Lehner R, Blank F, Petri-Fink A, Rothen-Rutishauser B. Biodistribution, Clearance, and Long-Term Fate of Clinically Relevant Nanomaterials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1704307. [PMID: 29389049 DOI: 10.1002/adma.201704307] [Citation(s) in RCA: 231] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/20/2017] [Indexed: 05/18/2023]
Abstract
Realization of the immense potential of nanomaterials for biomedical applications will require a thorough understanding of how they interact with cells, tissues, and organs. There is evidence that, depending on their physicochemical properties and subsequent interactions, nanomaterials are indeed taken up by cells. However, the subsequent release and/or intracellular degradation of the materials, transfer to other cells, and/or translocation across tissue barriers are still poorly understood. The involvement of these cellular clearance mechanisms strongly influences the long-term fate of used nanomaterials, especially if one also considers repeated exposure. Several nanomaterials, such as liposomes and iron oxide, gold, or silica nanoparticles, are already approved by the American Food and Drug Administration for clinical trials; however, there is still a huge gap of knowledge concerning their fate in the body. Herein, clinically relevant nanomaterials, their possible modes of exposure, as well as the biological barriers they must overcome to be effective are reviewed. Furthermore, the biodistribution and kinetics of nanomaterials and their modes of clearance are discussed, knowledge of the long-term fates of a selection of nanomaterials is summarized, and the critical points that must be considered for future research are addressed.
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Affiliation(s)
- Joël Bourquin
- Adolphe Merkle InstituteUniversity of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Ana Milosevic
- Adolphe Merkle InstituteUniversity of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Daniel Hauser
- Adolphe Merkle InstituteUniversity of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Roman Lehner
- Adolphe Merkle InstituteUniversity of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Fabian Blank
- Respiratory Medicine, Department of Biomedical Research, University of Bern, Murtenstrasse 50, 3008, Bern
| | - Alke Petri-Fink
- Adolphe Merkle InstituteUniversity of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland
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63
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Lu W, Gómez NM, Lim JC, Guha S, O'Brien-Jenkins A, Coffey EE, Campagno KE, McCaughey SA, Laties AM, Carlsson LG, Mitchell CH. The P2Y 12 Receptor Antagonist Ticagrelor Reduces Lysosomal pH and Autofluorescence in Retinal Pigmented Epithelial Cells From the ABCA4 -/- Mouse Model of Retinal Degeneration. Front Pharmacol 2018; 9:242. [PMID: 29725296 PMCID: PMC5917064 DOI: 10.3389/fphar.2018.00242] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 03/05/2018] [Indexed: 11/13/2022] Open
Abstract
The accumulation of partially degraded lipid waste in lysosomal-related organelles may contribute to pathology in many aging diseases. The presence of these lipofuscin granules is particularly evident in the autofluorescent lysosome-associated organelles of the retinal pigmented epithelial (RPE) cells, and may be related to early stages of age-related macular degeneration. While lysosomal enzymes degrade material optimally at acidic pH levels, lysosomal pH is elevated in RPE cells from the ABCA4-/- mouse model of Stargardt's disease, an early onset retinal degeneration. Lowering lysosomal pH through cAMP-dependent pathways decreases accumulation of autofluorescent material in RPE cells in vitro, but identification of an appropriate receptor is crucial for manipulating this pathway in vivo. As the P2Y12 receptor for ADP is coupled to the inhibitory Gi protein, we asked whether blocking the P2Y12 receptor with ticagrelor could restore lysosomal acidity and reduce autofluorescence in compromised RPE cells from ABCA4-/- mice. Oral delivery of ticagrelor giving rise to clinically relevant exposure lowered lysosomal pH in these RPE cells. Ticagrelor also partially reduced autofluorescence in the RPE cells of ABCA4-/- mice. In vitro studies in ARPE-19 cells using more specific antagonists AR-C69931 and AR-C66096 confirmed the importance of the P2Y12 receptor for lowering lysosomal pH and reducing autofluorescence. These observations identify P2Y12 receptor blockade as a potential target to lower lysosomal pH and clear lysosomal waste in RPE cells.
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Affiliation(s)
- Wennan Lu
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Néstor M Gómez
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Jason C Lim
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Sonia Guha
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States.,Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Ann O'Brien-Jenkins
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Erin E Coffey
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Keith E Campagno
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Stuart A McCaughey
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Alan M Laties
- Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Leif G Carlsson
- Department of Bioscience Heart Failure, Cardiovascular, Renal and Metabolic Diseases, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, United States.,Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, United States.,Department of Physiology, University of Pennsylvania, Philadelphia, PA, United States
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64
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Tharkeshwar AK, Gevaert K, Annaert W. Organellar Omics-A Reviving Strategy to Untangle the Biomolecular Complexity of the Cell. Proteomics 2017; 18:e1700113. [PMID: 29125683 DOI: 10.1002/pmic.201700113] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 10/23/2017] [Indexed: 12/18/2022]
Abstract
A eukaryotic cell encompasses many membrane-enclosed organelles, each of these holding several types of biomolecules that exhibit tremendous diversity in terms of their localization and expression. Despite the development of increasingly sensitive analytical tools, the enormous biomolecular complexity that exists within a cell cannot yet be fully resolved as low abundant molecules often remain unrecognized. Moreover, a drawback of whole cell analysis is that it does not provide spatial information and therefore it is not capable of assigning distinct biomolecules to specific compartments or analyzing changes in the composition of these compartments. Reduction of the biomolecular complexity of a sample helps to identify low abundant molecules, but such a reductionist approach requires methods that enable proper isolation and purification of individual cellular organelles. Decades of research have led to the development of a plethora of isolation methods for a broad range of subcellular organelles; yet, in particular, intrinsically dynamic compartments belonging to the endocytic machinery, including the plasma membrane, remain difficult to isolate in a sufficiently pure fraction. In this review, we discuss various methods that are commonly used to isolate subcellular organelles from cells and evaluate their advantages and disadvantages.
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Affiliation(s)
- Arun Kumar Tharkeshwar
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium.,Laboratory for Membrane Trafficking, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Department of Cell Biology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium.,Department of Biochemistry, Ghent University, Belgium
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium.,Laboratory for Membrane Trafficking, Department of Neurosciences, KU Leuven, Leuven, Belgium
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65
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Sharma A, Vaghasiya K, Ray E, Verma RK. Lysosomal targeting strategies for design and delivery of bioactive for therapeutic interventions. J Drug Target 2017; 26:208-221. [DOI: 10.1080/1061186x.2017.1374390] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Ankur Sharma
- Institute of Nano Science and Technology (INST), Phase 10, Mohali, India
| | - Kalpesh Vaghasiya
- Institute of Nano Science and Technology (INST), Phase 10, Mohali, India
| | - Eupa Ray
- Institute of Nano Science and Technology (INST), Phase 10, Mohali, India
| | - Rahul Kumar Verma
- Institute of Nano Science and Technology (INST), Phase 10, Mohali, India
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66
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Solomon M, Muro S. Lysosomal enzyme replacement therapies: Historical development, clinical outcomes, and future perspectives. Adv Drug Deliv Rev 2017; 118:109-134. [PMID: 28502768 PMCID: PMC5828774 DOI: 10.1016/j.addr.2017.05.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/26/2017] [Accepted: 05/08/2017] [Indexed: 01/06/2023]
Abstract
Lysosomes and lysosomal enzymes play a central role in numerous cellular processes, including cellular nutrition, recycling, signaling, defense, and cell death. Genetic deficiencies of lysosomal components, most commonly enzymes, are known as "lysosomal storage disorders" or "lysosomal diseases" (LDs) and lead to lysosomal dysfunction. LDs broadly affect peripheral organs and the central nervous system (CNS), debilitating patients and frequently causing fatality. Among other approaches, enzyme replacement therapy (ERT) has advanced to the clinic and represents a beneficial strategy for 8 out of the 50-60 known LDs. However, despite its value, current ERT suffers from several shortcomings, including various side effects, development of "resistance", and suboptimal delivery throughout the body, particularly to the CNS, lowering the therapeutic outcome and precluding the use of this strategy for a majority of LDs. This review offers an overview of the biomedical causes of LDs, their socio-medical relevance, treatment modalities and caveats, experimental alternatives, and future treatment perspectives.
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Affiliation(s)
- Melani Solomon
- Institute for Bioscience and Biotechnology Research, University Maryland, College Park, MD 20742, USA
| | - Silvia Muro
- Institute for Bioscience and Biotechnology Research, University Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University Maryland, College Park, MD 20742, USA.
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67
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Liu WJ, Li ZH, Chen XC, Zhao XL, Zhong Z, Yang C, Wu HL, An N, Li WY, Liu HF. Blockage of the lysosome-dependent autophagic pathway contributes to complement membrane attack complex-induced podocyte injury in idiopathic membranous nephropathy. Sci Rep 2017; 7:8643. [PMID: 28819100 PMCID: PMC5561110 DOI: 10.1038/s41598-017-07889-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 07/05/2017] [Indexed: 11/21/2022] Open
Abstract
Dysregulation of autophagy-mediated podocyte homeostasis is proposed to play a role in idiopathic membranous nephropathy (IMN). In the present study, autophagic activity and lysosomal alterations were investigated in podocytes of IMN patients and in cultured podocytes exposed to sublytic terminal complement complex, C5b-9. C5b-9 upregulated the number of LC3 positive puncta and the expression of p62 in patient podocytes and in C5b-9 injuried podocyte model. The lysosomal turnover of LC3-II was not influenced, although the BECN1 expression level was upregulated after exposure of podocytes to C5b-9. C5b-9 also caused a significant increase in the number of autophagosomes but not autolysosomes, suggesting that C5b-9 impairs the lysosomal degration of autophagosomes. Moreover, C5b-9 exacerbated the apoptosis of podocytes, which could be mimicked by chloroquine treatment, indicating that C5b-9 triggered podocyte injury, at least partially through inhibiting autophagy. Subsequent studies revealed that C5b-9 triggered lysosomal membrane permeabilization, which likely caused the decrease in enzymatic activity, defective acidification of lysosomes, and suppression of DQ-ovalbumin degradation. Taken together, our results suggest that the lysosomal-dependent autophagic pathway is blocked by C5b-9, which may play a key role in podocyte injury during the development of IMN.
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Affiliation(s)
- Wei Jing Liu
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China.,Renal Research Institution of Beijing University of Chinese Medicine, and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, 100700, China
| | - Zhi-Hang Li
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Xiao-Cui Chen
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Xiao-Lu Zhao
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Zhen Zhong
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Chen Yang
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Hong-Luan Wu
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Ning An
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Wei-Yan Li
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China
| | - Hua-Feng Liu
- Institute of Nephrology, and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, Guangdong, 524001, China.
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68
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Singh MS, Tammam SN, Shetab Boushehri MA, Lamprecht A. MDR in cancer: Addressing the underlying cellular alterations with the use of nanocarriers. Pharmacol Res 2017; 126:2-30. [PMID: 28760489 DOI: 10.1016/j.phrs.2017.07.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/29/2017] [Accepted: 07/26/2017] [Indexed: 01/02/2023]
Abstract
Multidrug resistance (MDR) is associated with a wide range of pathological changes at different cellular and intracellular levels. Nanoparticles (NPs) have been extensively exploited as the carriers of MDR reversing payloads to resistant tumor cells. However, when properly formulated in terms of chemical composition and physicochemical properties, NPs can serve as beyond delivery systems and help overcome MDR even without carrying a load of chemosensitizers or MDR reversing molecular cargos. Whether serving as drug carriers or beyond, a wise design of the nanoparticulate systems to overcome the cellular and intracellular alterations underlying the resistance is imperative. Within the current review, we will initially discuss the cellular changes occurring in resistant cells and how such changes lead to chemotherapy failure and cancer cell survival. We will then focus on different mechanisms through which nanosystems with appropriate chemical composition and physicochemical properties can serve as MDR reversing units at different cellular and intracellular levels according to the changes that underlie the resistance. Finally, we will conclude by discussing logical grounds for a wise and rational design of MDR reversing nanoparticulate systems to improve the cancer therapeutic approaches.
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Affiliation(s)
- Manu S Singh
- Department of Pharmaceutical Technology and Biopharmceutics, University of Bonn, Germany
| | - Salma N Tammam
- Department of Pharmaceutical Technology and Biopharmceutics, University of Bonn, Germany; Department of Pharmaceutical Technology, German University of Cairo, Egypt
| | | | - Alf Lamprecht
- Department of Pharmaceutical Technology and Biopharmceutics, University of Bonn, Germany; Laboratory of Pharmaceutical Engineering (EA4267), University of Franche-Comté, Besançon, France.
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69
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Haidar M, Timmerman V. Autophagy as an Emerging Common Pathomechanism in Inherited Peripheral Neuropathies. Front Mol Neurosci 2017; 10:143. [PMID: 28553203 PMCID: PMC5425483 DOI: 10.3389/fnmol.2017.00143] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 04/26/2017] [Indexed: 12/16/2022] Open
Abstract
The inherited peripheral neuropathies (IPNs) comprise a growing list of genetically heterogeneous diseases. With mutations in more than 80 genes being reported to cause IPNs, a wide spectrum of functional consequences is expected to follow this genotypic diversity. Hence, the search for a common pathomechanism among the different phenotypes has become the holy grail of functional research into IPNs. During the last decade, studies on several affected genes have shown a direct and/or indirect correlation with autophagy. Autophagy, a cellular homeostatic process, is required for the removal of cell aggregates, long-lived proteins and dead organelles from the cell in double-membraned vesicles destined for the lysosomes. As an evolutionarily highly conserved process, autophagy is essential for the survival and proper functioning of the cell. Recently, neuronal cells have been shown to be particularly vulnerable to disruption of the autophagic pathway. Furthermore, autophagy has been shown to be affected in various common neurodegenerative diseases of both the central and the peripheral nervous system including Alzheimer's, Parkinson's, and Huntington's diseases. In this review we provide an overview of the genes involved in hereditary neuropathies which are linked to autophagy and we propose the disruption of the autophagic flux as an emerging common pathomechanism. We also shed light on the different steps of the autophagy pathway linked to these genes. Finally, we review the concept of autophagy being a therapeutic target in IPNs, and the possibilities and challenges of this pathway-specific targeting.
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Affiliation(s)
- Mansour Haidar
- Peripheral Neuropathy Research Group, Institute Born Bunge, University of AntwerpAntwerpen, Belgium
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Institute Born Bunge, University of AntwerpAntwerpen, Belgium
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70
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Pascua-Maestro R, Diez-Hermano S, Lillo C, Ganfornina MD, Sanchez D. Protecting cells by protecting their vulnerable lysosomes: Identification of a new mechanism for preserving lysosomal functional integrity upon oxidative stress. PLoS Genet 2017; 13:e1006603. [PMID: 28182653 PMCID: PMC5325589 DOI: 10.1371/journal.pgen.1006603] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/24/2017] [Accepted: 01/24/2017] [Indexed: 12/31/2022] Open
Abstract
Environmental insults such as oxidative stress can damage cell membranes. Lysosomes are particularly sensitive to membrane permeabilization since their function depends on intraluminal acidic pH and requires stable membrane-dependent proton gradients. Among the catalog of oxidative stress-responsive genes is the Lipocalin Apolipoprotein D (ApoD), an extracellular lipid binding protein endowed with antioxidant capacity. Within the nervous system, cell types in the defense frontline, such as astrocytes, secrete ApoD to help neurons cope with the challenge. The protecting role of ApoD is known from cellular to organism level, and many of its downstream effects, including optimization of autophagy upon neurodegeneration, have been described. However, we still cannot assign a cellular mechanism to ApoD gene that explains how this protection is accomplished. Here we perform a comprehensive analysis of ApoD intracellular traffic and demonstrate its role in lysosomal pH homeostasis upon paraquat-induced oxidative stress. By combining single-lysosome in vivo pH measurements with immunodetection, we demonstrate that ApoD is endocytosed and targeted to a subset of vulnerable lysosomes in a stress-dependent manner. ApoD is functionally stable in this acidic environment, and its presence is sufficient and necessary for lysosomes to recover from oxidation-induced alkalinization, both in astrocytes and neurons. This function is accomplished by preventing lysosomal membrane permeabilization. Two lysosomal-dependent biological processes, myelin phagocytosis by astrocytes and optimization of neurodegeneration-triggered autophagy in a Drosophila in vivo model, require ApoD-related Lipocalins. Our results uncover a previously unknown biological function of ApoD, member of the finely regulated and evolutionary conserved gene family of extracellular Lipocalins. They set a lipoprotein-mediated regulation of lysosomal membrane integrity as a new mechanism at the hub of many cellular functions, critical for the outcome of a wide variety of neurodegenerative diseases. These results open therapeutic opportunities by providing a route of entry and a repair mechanism for lysosomes in pathological situations. This work is the result of our search for the mechanism of action of Apolipoprotein D (ApoD), a neuroprotective lipid-binding protein that confers cell resistance to oxidative stress. ApoD is one of the few genes consistently over-expressed in the aging brain of all vertebrate species, and no nervous system disease has been found concurring without ApoD over-expression. All evidence supports ApoD as an endogenous mechanism of protection. We demonstrate here that this extracellular lipid binding protein is endocytosed and targeted in a finely controlled way to subsets of lysosomes in need of protection, those most sensitive to oxidative stress. ApoD reveals the existence of biologically relevant lysosomal heterogeneity that conditions the oxidation state of cells, their phagocytic or autophagic capacity, and the final output in neurodegenerative conditions. The stable presence of ApoD in lysosomes is sufficient and necessary for lysosomes to recover from oxidation-induced membrane permeabilization and loss of proton gradients. ApoD-mediated control of lysosomal membrane integrity represents a new cell-protection mechanism at the hub of many cellular functions, and is critical for the outcome of a wide variety of neurodegenerative diseases. Therapeutic opportunities open, by providing a route of entry and a repair mechanism for lysosomes in pathological situations.
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Affiliation(s)
- Raquel Pascua-Maestro
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Sergio Diez-Hermano
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Concepción Lillo
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
| | - Maria D. Ganfornina
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
- * E-mail: (MDG); (DS)
| | - Diego Sanchez
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
- * E-mail: (MDG); (DS)
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71
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da Luz CM, Boyles MSP, Falagan-Lotsch P, Pereira MR, Tutumi HR, de Oliveira Santos E, Martins NB, Himly M, Sommer A, Foissner I, Duschl A, Granjeiro JM, Leite PEC. Poly-lactic acid nanoparticles (PLA-NP) promote physiological modifications in lung epithelial cells and are internalized by clathrin-coated pits and lipid rafts. J Nanobiotechnology 2017; 15:11. [PMID: 28143572 PMCID: PMC5282631 DOI: 10.1186/s12951-016-0238-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/03/2016] [Indexed: 02/07/2023] Open
Abstract
Background Poly-lactic acid nanoparticles (PLA-NP) are a type of polymeric NP, frequently used as nanomedicines, which have advantages over metallic NP such as the ability to maintain therapeutic drug levels for sustained periods of time. Despite PLA-NP being considered biocompatible, data concerning alterations in cellular physiology are scarce. Methods We conducted an extensive evaluation of PLA-NP biocompatibility in human lung epithelial A549 cells using high throughput screening and more complex methodologies. These included measurements of cytotoxicity, cell viability, immunomodulatory potential, and effects upon the cells’ proteome. We used non- and green-fluorescent PLA-NP with 63 and 66 nm diameters, respectively. Cells were exposed with concentrations of 2, 20, 100 and 200 µg/mL, for 24, 48 and 72 h, in most experiments. Moreover, possible endocytic mechanisms of internalization of PLA-NP were investigated, such as those involving caveolae, lipid rafts, macropinocytosis and clathrin-coated pits. Results Cell viability and proliferation were not altered in response to PLA-NP. Multiplex analysis of secreted mediators revealed a low-level reduction of IL-12p70 and vascular epidermal growth factor (VEGF) in response to PLA-NP, while all other mediators assessed were unaffected. However, changes to the cells’ proteome were observed in response to PLA-NP, and, additionally, the cellular stress marker miR155 was found to reduce. In dual exposures of staurosporine (STS) with PLA-NP, PLA-NP enhanced susceptibility to STS-induced cell death. Finally, PLA-NP were rapidly internalized in association with clathrin-coated pits, and, to a lesser extent, with lipid rafts. Conclusions These data demonstrate that PLA-NP are internalized and, in general, tolerated by A549 cells, with no cytotoxicity and no secretion of pro-inflammatory mediators. However, PLA-NP exposure may induce modification of biological functions of A549 cells, which should be considered when designing drug delivery systems. Moreover, the pathways of PLA-NP internalization we detected could contribute to the improvement of selective uptake strategies. Electronic supplementary material The online version of this article (doi:10.1186/s12951-016-0238-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Camila Macedo da Luz
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil
| | - Matthew Samuel Powys Boyles
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria.,Heriot-Watt University, Edinburg, UK
| | - Priscila Falagan-Lotsch
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil
| | - Mariana Rodrigues Pereira
- Laboratory of Chemical Signaling in Nervous System, Biology Institute, Fluminense Federal University, Niteroi, RJ, Brazil
| | - Henrique Rudolf Tutumi
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil
| | - Eidy de Oliveira Santos
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil.,Laboratory of Biochemistry, State University Center of West Zone (UEZO), Rio de Janeiro, RJ, Brazil
| | - Nathalia Balthazar Martins
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil
| | - Martin Himly
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Aniela Sommer
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Ilse Foissner
- Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Albert Duschl
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - José Mauro Granjeiro
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil.,Dental School, Fluminense Federal University, Niteroi, RJ, Brazil
| | - Paulo Emílio Corrêa Leite
- Laboratory of Bioengineering and in Vitro Toxicology, Directory of Metrology Applied to Life Sciences (Dimav), National Institute of Metrology Quality and Technology (INMETRO), Duque De Caxias, RJ, Brazil. .,, Av. Nossa Senhora das Gracas 50, LABET - Dimav, Predio 27, Duque de Caxias, Xerem, Rio de Janeiro, 25250-020, Brazil.
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72
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Moors TE, Hoozemans JJM, Ingrassia A, Beccari T, Parnetti L, Chartier-Harlin MC, van de Berg WDJ. Therapeutic potential of autophagy-enhancing agents in Parkinson's disease. Mol Neurodegener 2017; 12:11. [PMID: 28122627 PMCID: PMC5267440 DOI: 10.1186/s13024-017-0154-3] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 01/18/2017] [Indexed: 01/07/2023] Open
Abstract
Converging evidence from genetic, pathological and experimental studies have increasingly suggested an important role for autophagy impairment in Parkinson’s Disease (PD). Genetic studies have identified mutations in genes encoding for components of the autophagy-lysosomal pathway (ALP), including glucosidase beta acid 1 (GBA1), that are associated with increased risk for developing PD. Observations in PD brain tissue suggest an aberrant regulation of autophagy associated with the aggregation of α-synuclein (α-syn). As autophagy is one of the main systems involved in the proteolytic degradation of α-syn, pharmacological enhancement of autophagy may be an attractive strategy to combat α-syn aggregation in PD. Here, we review the potential of autophagy enhancement as disease-modifying therapy in PD based on preclinical evidence. In particular, we provide an overview of the molecular regulation of autophagy and targets for pharmacological modulation within the ALP. In experimental models, beneficial effects on multiple pathological processes involved in PD, including α-syn aggregation, cell death, oxidative stress and mitochondrial dysfunction, have been demonstrated using the autophagy enhancers rapamycin and lithium. However, selectivity of these agents is limited, while upstream ALP signaling proteins are involved in many other pathways than autophagy. Broad stimulation of autophagy may therefore cause a wide spectrum of dose-dependent side-effects, suggesting that its clinical applicability is limited. However, recently developed agents selectively targeting core ALP components, including Transcription Factor EB (TFEB), lysosomes, GCase as well as chaperone-mediated autophagy regulators, exert more specific effects on molecular pathogenetic processes causing PD. To conclude, the targeted manipulation of downstream ALP components, rather than broad autophagy stimulation, may be an attractive strategy for the development of novel pharmacological therapies in PD. Further characterization of dysfunctional autophagy in different stages and molecular subtypes of PD in combination with the clinical translation of downstream autophagy regulation offers exciting new avenues for future drug development.
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Affiliation(s)
- Tim E Moors
- Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam Neuroscience, VU University Medical Center Amsterdam, Amsterdam, The Netherlands.
| | - Jeroen J M Hoozemans
- Department of Pathology, Amsterdam Neuroscience, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Angela Ingrassia
- Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam Neuroscience, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Tommaso Beccari
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Lucilla Parnetti
- Department of Medicine, Section of Neurology, University of Perugia, Perugia, Italy
| | - Marie-Christine Chartier-Harlin
- UMR-S 1172-JPArc-Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer, University of Lille, Lille, F-59000, France.,Inserm, UMR-S 1172, Team "Early stages of Parkinson's disease", F-59000, Lille, France
| | - Wilma D J van de Berg
- Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam Neuroscience, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
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73
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Abstract
Following cellular engulfment, nanoparticles end up in the lysosomes, making them an ideal tool for modifying the lysosomal environment. Here, we describe how acidic nanoparticles can be used to lower the pH of lysosomes in cultured, primary astrocytes and thereby increase their degradation capacity. To guarantee that the cell culture is completely devoid of professional phagocytes, we isolate, expand, and differentiate neural stem cells from embryonic mouse cortex to achieve astrocytes for these experiments. Immunostainings with LAMP2-specific antibodies can be performed to verify the lysosomal localization of the nanoparticles, and the effect on lysosomal acidification can easily be followed with LysoTracker dye.
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Affiliation(s)
- Camilla Lööv
- MassGeneral Institute for Neurodegeneration, Massachusetts General Hospital, Harvard Medical School, MA, 02129, Charlestown, USA
| | - Anna Erlandsson
- Department of Public Health & Caring Sciences/Molecular Geriatrics, Rudbeck Laboratory, Uppsala University, 751 85, Uppsala, Sweden.
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74
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Bourdenx M, Daniel J, Genin E, Soria FN, Blanchard-Desce M, Bezard E, Dehay B. Nanoparticles restore lysosomal acidification defects: Implications for Parkinson and other lysosomal-related diseases. Autophagy 2016; 12:472-83. [PMID: 26761717 DOI: 10.1080/15548627.2015.1136769] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Lysosomal impairment causes lysosomal storage disorders (LSD) and is involved in pathogenesis of neurodegenerative diseases, notably Parkinson disease (PD). Strategies enhancing or restoring lysosomal-mediated degradation thus appear as tantalizing disease-modifying therapeutics. Here we demonstrate that poly(DL-lactide-co-glycolide) (PLGA) acidic nanoparticles (aNP) restore impaired lysosomal function in a series of toxin and genetic cellular models of PD, i.e. ATP13A2-mutant or depleted cells or glucocerebrosidase (GBA)-mutant cells, as well as in a genetic model of lysosomal-related myopathy. We show that PLGA-aNP are transported to the lysosome within 24 h, lower lysosomal pH and rescue chloroquine (CQ)-induced toxicity. Re-acidification of defective lysosomes following PLGA-aNP treatment restores lysosomal function in different pathological contexts. Finally, our results show that PLGA-aNP may be detected after intracerebral injection in neurons and attenuate PD-related neurodegeneration in vivo by mechanisms involving a rescue of compromised lysosomes.
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Affiliation(s)
- Mathieu Bourdenx
- a University de Bordeaux, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France.,b CNRS, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France
| | - Jonathan Daniel
- c University de Bordeaux, Institut des Sciences Moléculaires , UMR 5255, Talence , France
| | - Emilie Genin
- c University de Bordeaux, Institut des Sciences Moléculaires , UMR 5255, Talence , France
| | - Federico N Soria
- a University de Bordeaux, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France.,b CNRS, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France
| | | | - Erwan Bezard
- a University de Bordeaux, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France.,b CNRS, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France
| | - Benjamin Dehay
- a University de Bordeaux, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France.,b CNRS, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France
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75
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Colacurcio DJ, Nixon RA. Disorders of lysosomal acidification-The emerging role of v-ATPase in aging and neurodegenerative disease. Ageing Res Rev 2016; 32:75-88. [PMID: 27197071 DOI: 10.1016/j.arr.2016.05.004] [Citation(s) in RCA: 320] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/02/2016] [Accepted: 05/13/2016] [Indexed: 12/21/2022]
Abstract
Autophagy and endocytosis deliver unneeded cellular materials to lysosomes for degradation. Beyond processing cellular waste, lysosomes release metabolites and ions that serve signaling and nutrient sensing roles, linking the functions of the lysosome to various pathways for intracellular metabolism and nutrient homeostasis. Each of these lysosomal behaviors is influenced by the intraluminal pH of the lysosome, which is maintained in the low acidic range by a proton pump, the vacuolar ATPase (v-ATPase). New reports implicate altered v-ATPase activity and lysosomal pH dysregulation in cellular aging, longevity, and adult-onset neurodegenerative diseases, including forms of Parkinson disease and Alzheimer disease. Genetic defects of subunits composing the v-ATPase or v-ATPase-related proteins occur in an increasingly recognized group of familial neurodegenerative diseases. Here, we review the expanding roles of the v-ATPase complex as a platform regulating lysosomal hydrolysis and cellular homeostasis. We discuss the unique vulnerability of neurons to persistent low level lysosomal dysfunction and review recent clinical and experimental studies that link dysfunction of the v-ATPase complex to neurodegenerative diseases across the age spectrum.
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76
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Boya P, Esteban-Martínez L, Serrano-Puebla A, Gómez-Sintes R, Villarejo-Zori B. Autophagy in the eye: Development, degeneration, and aging. Prog Retin Eye Res 2016; 55:206-245. [PMID: 27566190 DOI: 10.1016/j.preteyeres.2016.08.001] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 02/06/2023]
Abstract
Autophagy is a catabolic pathway that promotes the degradation and recycling of cellular components. Proteins, lipids, and even whole organelles are engulfed in autophagosomes and delivered to the lysosome for elimination. In response to stress, autophagy mediates the degradation of cell components, which are recycled to generate the nutrients and building blocks required to sustain cellular homeostasis. Moreover, it plays an important role in cellular quality control, particularly in neurons, in which the total burden of altered proteins and damaged organelles cannot be reduced by redistribution to daughter cells through cell division. Research has only begun to examine the role of autophagy in the visual system. The retina, a light-sensitive tissue, detects and transmits electrical impulses through the optic nerve to the visual cortex in the brain. Both the retina and the eye are exposed to a variety of environmental insults and stressors, including genetic mutations and age-associated alterations that impair their function. Here, we review the main studies that have sought to explain autophagy's importance in visual function. We describe the role of autophagy in retinal development and cell differentiation, and discuss the implications of autophagy dysregulation both in physiological aging and in important diseases such as age-associated macular degeneration and glaucoma. We also address the putative role of autophagy in promoting photoreceptor survival and discuss how selective autophagy could provide alternative means of protecting retinal cells. The findings reviewed here underscore the important role of autophagy in maintaining proper retinal function and highlight novel therapeutic approaches for blindness and other diseases of the eye.
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Affiliation(s)
- Patricia Boya
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - Lorena Esteban-Martínez
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Ana Serrano-Puebla
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Raquel Gómez-Sintes
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Villarejo-Zori
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
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77
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Trudeau KM, Colby AH, Zeng J, Las G, Feng JH, Grinstaff MW, Shirihai OS. Lysosome acidification by photoactivated nanoparticles restores autophagy under lipotoxicity. J Cell Biol 2016; 214:25-34. [PMID: 27377248 PMCID: PMC4932370 DOI: 10.1083/jcb.201511042] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 06/15/2016] [Indexed: 12/11/2022] Open
Abstract
In pancreatic β-cells, liver hepatocytes, and cardiomyocytes, chronic exposure to high levels of fatty acids (lipotoxicity) inhibits autophagic flux and concomitantly decreases lysosomal acidity. Whether impaired lysosomal acidification is causally inhibiting autophagic flux and cellular functions could not, up to the present, be determined because of the lack of an approach to modify lysosomal acidity. To address this question, lysosome-localizing nanoparticles are described that, upon UV photoactivation, enable controlled acidification of impaired lysosomes. The photoactivatable, acidifying nanoparticles (paNPs) demonstrate lysosomal uptake in INS1 and mouse β-cells. Photoactivation of paNPs in fatty acid-treated INS1 cells enhances lysosomal acidity and function while decreasing p62 and LC3-II levels, indicating rescue of autophagic flux upon acute lysosomal acidification. Furthermore, paNPs improve glucose-stimulated insulin secretion that is reduced under lipotoxicity in INS1 cells and mouse islets. These results establish a causative role for impaired lysosomal acidification in the deregulation of autophagy and β-cell function under lipotoxicity.
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Affiliation(s)
- Kyle M Trudeau
- Obesity and Nutrition Section, Department of Medicine, Evans Biomedical Research Center, Boston University School of Medicine, Boston, MA 02118
| | - Aaron H Colby
- Departments of Biomedical Engineering, Chemistry, and Medicine, Boston University, Boston, MA 02215 Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215
| | - Jialiu Zeng
- Departments of Biomedical Engineering, Chemistry, and Medicine, Boston University, Boston, MA 02215
| | - Guy Las
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103, Israel
| | - Jiazuo H Feng
- Departments of Biomedical Engineering, Chemistry, and Medicine, Boston University, Boston, MA 02215
| | - Mark W Grinstaff
- Departments of Biomedical Engineering, Chemistry, and Medicine, Boston University, Boston, MA 02215
| | - Orian S Shirihai
- Obesity and Nutrition Section, Department of Medicine, Evans Biomedical Research Center, Boston University School of Medicine, Boston, MA 02118 Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103, Israel Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90045
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78
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Dehay B, Decressac M, Bourdenx M, Guadagnino I, Fernagut PO, Tamburrino A, Bassil F, Meissner WG, Bezard E. Targeting α-synuclein: Therapeutic options. Mov Disord 2016; 31:882-8. [PMID: 26926119 DOI: 10.1002/mds.26568] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/09/2016] [Accepted: 01/14/2016] [Indexed: 12/21/2022] Open
Abstract
The discovery of the central role of α-synuclein (αSyn) in the pathogenesis of Parkinson's disease (PD) has powered, in the last decade, the emergence of novel relevant models of this condition based on viral vector-mediated expression of the disease-causing protein or inoculation of toxic species of αSyn. Although the development of these powerful tools and models has provided considerable insights into the mechanisms underlying neurodegeneration in PD, it has also been translated into the expansion of the landscape of preclinical therapeutic strategies. Much attention is now brought to the proteotoxic mechanisms induced by αSyn and how to block them using strategies inspired by intrinsic cellular pathways such as the enhancement of cellular clearance by the lysosomal-autophagic system, through proteasome-mediated degradation or through immunization. The important effort undertaken by several laboratories and consortia to tackle these issues and identify novel targets warrants great promise for the discovery not only of neuroprotective approaches but also of restorative strategies for PD and other synucleinopathies. In this viewpoint, we summarize the latest advances in this new area of PD research and will discuss promising approaches and ongoing challenges. © 2016 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Benjamin Dehay
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | | | - Mathieu Bourdenx
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | | | - Pierre-Olivier Fernagut
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Anna Tamburrino
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Fares Bassil
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Wassilios G Meissner
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,Department of Neurology, University Hospital Bordeaux, Bordeaux, France
| | - Erwan Bezard
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
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79
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Thimiri Govinda Raj DB, Khan NA. Designer nanoparticle: nanobiotechnology tool for cell biology. NANO CONVERGENCE 2016; 3:22. [PMID: 28191432 PMCID: PMC5271163 DOI: 10.1186/s40580-016-0082-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 08/29/2016] [Indexed: 05/17/2023]
Abstract
This article discusses the use of nanotechnology for subcellular compartment isolation and its application towards subcellular omics. This technology review significantly contributes to our understanding on use of nanotechnology for subcellular systems biology. Here we elaborate nanobiotechnology approach of using superparamagnetic nanoparticles (SPMNPs) optimized with different surface coatings for subcellular organelle isolation. Using pulse-chase approach, we review that SPMNPs interacted differently with the cell depending on its surface functionalization. The article focuses on the use of functionalized-SPMNPs as a nanobiotechnology tool to isolate high quality (both purity and yield) plasma membranes and endosomes or lysosomes. Such nanobiotechnology tool can be applied in generating subcellular compartment inventories. As a future perspective, this strategy could be applied in areas such as immunology, cancer and stem cell research.
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Affiliation(s)
- Deepak B. Thimiri Govinda Raj
- European Molecular Biology Laboratory (EMBL), Grenoble Outstation and Unit of Virus Host-Cell Interactions (UVHCI), UJF-EMBL-CNRS, UMR 5233 Grenoble, France
- Envirotransgene Bio-solutions Global, Chennai, India
- Biotechnology Centre for Oslo, Centre for Molecular Medicine Norway (NCMM), P.O. Box 1137, Blindern, 0318 Oslo, Norway
| | - Niamat Ali Khan
- Laboratory of Lipid Metabolism and Cancer, O&N I, Herestraat 49, Box 902, 3000 Louvain, Belgium
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80
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Song W, Popp L, Yang J, Kumar A, Gangoli VS, Segatori L. The autophagic response to polystyrene nanoparticles is mediated by transcription factor EB and depends on surface charge. J Nanobiotechnology 2015; 13:87. [PMID: 26596266 PMCID: PMC4657241 DOI: 10.1186/s12951-015-0149-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/13/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND A number of engineered nanoparticles induce autophagy, the main catabolic pathway that regulates bulk degradation of cytoplasmic material by the lysosomes. Depending on the specific physico-chemical properties of the nanomaterial, however, nanoparticle-induced autophagy may have different effects on cell physiology, ranging from enhanced autophagic degradation to blockage of autophagic flux. To investigate the molecular mechanisms underlying the impact of nanoparticle charge on the nature of the autophagic response, we tested polystyrene nanoparticles (50 nm) with neutral, anionic, and cationic surface charges. RESULTS We found all polystyrene nanoparticles investigated in this study to activate autophagy. We showed that internalization of polystyrene nanoparticles results in activation of the transcription factor EB, a master regulator of autophagy and lysosome biogenesis. Autophagic clearance, however, was observed to depend specifically on the charge of the nanoparticles. Particularly, we found that the autophagic response to polystyrene nanoparticles presenting a neutral or anionic surface involves enhanced clearance of autophagic cargo. Cell exposure to polystyrene nanoparticles presenting a cationic surface, on the other hand, results in transcriptional upregulation of the pathway, but also causes lysosomal dysfunction, ultimately resulting in blockage of autophagic flux. CONCLUSIONS This study furthers our understanding of the molecular mechanisms that regulate the autophagic response to nanoparticles, thus contributing essential design criteria for engineering benign nanomaterials.
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Affiliation(s)
- Wensi Song
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA.
| | - Lauren Popp
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA.
| | - Justin Yang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA.
| | - Ayushi Kumar
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA.
| | - Varun Shenoy Gangoli
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA.
| | - Laura Segatori
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA. .,Department of Biochemistry and Cell Biology, Rice University, Houston, TX, 77005, USA. .,Department of Bioengineering, Rice University, Houston, TX, 77005, USA.
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81
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Maurer LL, Yang X, Schindler AJ, Taggart RK, Jiang C, Hsu-Kim H, Sherwood DR, Meyer JN. Intracellular trafficking pathways in silver nanoparticle uptake and toxicity in Caenorhabditis elegans. Nanotoxicology 2015; 10:831-5. [PMID: 26559224 DOI: 10.3109/17435390.2015.1110759] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We used the nematode Caenorhabditis elegans to study the roles of endocytosis and lysosomal function in uptake and subsequent toxicity of silver nanoparticles (AgNP) in vivo. To focus on AgNP uptake and effects rather than silver ion (AgNO3) effects, we used a minimally dissolvable AgNP, citrate-coated AgNPs (CIT-AgNPs). We found that the clathrin-mediated endocytosis inhibitor chlorpromazine reduced the toxicity of CIT-AgNPs but not AgNO3. We also tested the sensitivity of three endocytosis-deficient mutants (rme-1, rme-6 and rme-8) and two lysosomal function deficient mutants (cup-5 and glo-1) as compared to wild-type (N2 strain). One of the endocytosis-deficient mutants (rme-6) took up less silver and was resistant to the acute toxicity of CIT-AgNPs compared to N2s. None of those mutants showed altered sensitivity to AgNO3. Lysosome and lysosome-related organelle mutants were more sensitive to the growth-inhibiting effects of both CIT-AgNPs and AgNO3. Our study provides mechanistic evidence suggesting that early endosome formation is necessary for AgNP-induced toxicity in vivo, as rme-6 mutants were less sensitive to the toxic effects of AgNPs than C. elegans with mutations involved in later steps in the endocytic process.
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Affiliation(s)
- Laura L Maurer
- a Nicholas School of the Environment, Duke University , Durham , NC , USA .,b Center for the Environmental Implications of Nanotechnology, Duke University , Durham , NC , USA
| | - Xinyu Yang
- a Nicholas School of the Environment, Duke University , Durham , NC , USA .,b Center for the Environmental Implications of Nanotechnology, Duke University , Durham , NC , USA
| | | | - Ross K Taggart
- b Center for the Environmental Implications of Nanotechnology, Duke University , Durham , NC , USA .,d Department of Civil & Environmental Engineering , Duke University , Durham , NC , USA
| | - Chuanjia Jiang
- b Center for the Environmental Implications of Nanotechnology, Duke University , Durham , NC , USA .,d Department of Civil & Environmental Engineering , Duke University , Durham , NC , USA
| | - Heileen Hsu-Kim
- b Center for the Environmental Implications of Nanotechnology, Duke University , Durham , NC , USA .,d Department of Civil & Environmental Engineering , Duke University , Durham , NC , USA
| | | | - Joel N Meyer
- a Nicholas School of the Environment, Duke University , Durham , NC , USA .,b Center for the Environmental Implications of Nanotechnology, Duke University , Durham , NC , USA
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82
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Wei PF, Jin PP, Barui AK, Hu Y, Zhang L, Zhang JQ, Shi SS, Zhang HR, Lin J, Zhou W, Zhang YJ, Ruan RQ, Patra CR, Wen LP. Differential ERK activation during autophagy induced by europium hydroxide nanorods and trehalose: Maximum clearance of huntingtin aggregates through combined treatment. Biomaterials 2015; 73:160-74. [PMID: 26409001 DOI: 10.1016/j.biomaterials.2015.09.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 09/03/2015] [Accepted: 09/09/2015] [Indexed: 12/18/2022]
Abstract
Accelerating the clearance of intracellular protein aggregates through elevation of autophagy represents a viable approach for the treatment of neurodegenerative diseases. In our earlier report, we have demonstrated the enhanced degradation of mutant huntingtin protein aggregates through autophagy process induced by europium hydroxide nanorods [EHNs: Eu(III)(OH)3], but the underlying molecular mechanism of EHNs mediated autophagy was unclear. The present report reveals that EHNs induced autophagy does not follow the classical AKT-mTOR and AMPK signaling pathways. The inhibition of ERK1/2 phosphorylation using the specific MEK inhibitor U0126 partially abrogates the autophagy as well as the clearance of mutant huntingtin protein aggregates mediated by EHNs suggesting that nanorods stimulate the activation of MEK/ERK1/2 signaling pathway during autophagy process. In contrast, another mTOR-independent autophagy inducer trehalose has been found to induce autophagy without activating ERK1/2 signaling pathway. Interestingly, the combined treatment of EHNs and trehalose leads to more degradation of mutant huntingtin protein aggregates than that obtained with single treatment of either nanorods or trehalose. Our results demonstrate the rational that further enhanced clearance of intracellular protein aggregates, needed for diverse neurodegenerative diseases, may be achieved through the combined treatment of two or more autophagy inducers, which stimulate autophagy through different signaling pathways.
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Affiliation(s)
- Peng-Fei Wei
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China
| | - Pei-Pei Jin
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Ayan Kumar Barui
- Biomaterials Group, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), 2 Rafi Marg, New Delhi, India
| | - Yi Hu
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Li Zhang
- Department of Urology, The First Affiliated Hospital of Anhui Medical University and Institute of Urology, Anhui Medical University, 230022 Hefei, China
| | - Ji-Qian Zhang
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Shan-Shan Shi
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Hou-Rui Zhang
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Jun Lin
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China
| | - Wei Zhou
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China
| | - Yun-Jiao Zhang
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China
| | - Ren-Quan Ruan
- Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China
| | - Chitta Ranjan Patra
- Biomaterials Group, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), 2 Rafi Marg, New Delhi, India.
| | - Long-Ping Wen
- The CAS Key Laboratory of Innate Immunity and Chronic Disease, Innovation Center for Cell Signaling Network, School of Life Sciences and Medical Center, University of Science and Technology of China, Hefei, Anhui 230027, China; Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China.
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Lee JH, McBrayer MK, Wolfe DM, Haslett LJ, Kumar A, Sato Y, Lie PPY, Mohan P, Coffey EE, Kompella U, Mitchell CH, Lloyd-Evans E, Nixon RA. Presenilin 1 Maintains Lysosomal Ca(2+) Homeostasis via TRPML1 by Regulating vATPase-Mediated Lysosome Acidification. Cell Rep 2015; 12:1430-44. [PMID: 26299959 DOI: 10.1016/j.celrep.2015.07.050] [Citation(s) in RCA: 259] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 04/22/2015] [Accepted: 07/24/2015] [Indexed: 12/28/2022] Open
Abstract
Presenilin 1 (PS1) deletion or Alzheimer's disease (AD)-linked mutations disrupt lysosomal acidification and proteolysis, which inhibits autophagy. Here, we establish that this phenotype stems from impaired glycosylation and instability of vATPase V0a1 subunit, causing deficient lysosomal vATPase assembly and function. We further demonstrate that elevated lysosomal pH in Presenilin 1 knockout (PS1KO) cells induces abnormal Ca(2+) efflux from lysosomes mediated by TRPML1 and elevates cytosolic Ca(2+). In WT cells, blocking vATPase activity or knockdown of either PS1 or the V0a1 subunit of vATPase reproduces all of these abnormalities. Normalizing lysosomal pH in PS1KO cells using acidic nanoparticles restores normal lysosomal proteolysis, autophagy, and Ca(2+) homeostasis, but correcting lysosomal Ca(2+) deficits alone neither re-acidifies lysosomes nor reverses proteolytic and autophagic deficits. Our results indicate that vATPase deficiency in PS1 loss-of-function states causes lysosomal/autophagy deficits and contributes to abnormal cellular Ca(2+) homeostasis, thus linking two AD-related pathogenic processes through a common molecular mechanism.
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Affiliation(s)
- Ju-Hyun Lee
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA
| | - Mary Kate McBrayer
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Devin M Wolfe
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Luke J Haslett
- Division of Pathophysiology and Repair, Cardiff University, Cardiff CF10 3XQ, UK
| | - Asok Kumar
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Pathology, New York University, New York, NY 10016, USA
| | - Yutaka Sato
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Pearl P Y Lie
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Panaiyur Mohan
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA
| | - Erin E Coffey
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Uday Kompella
- Pharmaceutical Science and Ophthalmology, University of Colorado, Aurora, CO 80045, USA
| | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emyr Lloyd-Evans
- Division of Pathophysiology and Repair, Cardiff University, Cardiff CF10 3XQ, UK
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA; Department of Cell Biology, New York University, New York, NY 10016, USA.
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84
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Lööv C, Mitchell CH, Simonsson M, Erlandsson A. Slow degradation in phagocytic astrocytes can be enhanced by lysosomal acidification. Glia 2015; 63:1997-2009. [PMID: 26095880 DOI: 10.1002/glia.22873] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 05/28/2015] [Indexed: 11/07/2022]
Abstract
Inefficient lysosomal degradation is central in the development of various brain disorders, but the underlying mechanisms and the involvement of different cell types remains elusive. We have previously shown that astrocytes effectively engulf dead cells, but then store, rather than degrade the ingested material. In the present study we identify reasons for the slow digestion and ways to accelerate degradation in primary astrocytes. Our results show that actin-rings surround the phagosomes for long periods of time, which physically inhibit the phago-lysosome fusion. Furthermore, astrocytes express high levels of Rab27a, a protein known to reduce the acidity of lysosomes by Nox2 recruitment, in order to preserve antigens for presentation. We found that Nox2 colocalizes with the ingested material, indicating that it may influence antigen processing also in astrocytes, as they express MHC class II. By inducing long-time acidification of astrocytic lysosomes using acidic nanoparticles, we could increase the digestion of astrocyte-ingested, dead cells. The degradation was, however, normalized over time, indicating that inhibitory pathways are up-regulated in response to the enhanced acidification. GLIA 2015;63:1997-2009.
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Affiliation(s)
- Camilla Lööv
- Department of Neuroscience, Uppsala University, Uppsala University Hospital Ent 85, 2nd Fl., Uppsala, Sweden
| | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Martin Simonsson
- SciLifeLab and Department of Computer Science, Electrical & Space Engineering, Luleå, University of Technology, Luleå, Sweden
| | - Anna Erlandsson
- Department of Neuroscience, Uppsala University, Uppsala University Hospital Ent 85, 2nd Fl., Uppsala, Sweden
- Department of Public Health and Caring Sciences, Uppsala University, Rudbeck Laboratory, Uppsala, Sweden
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85
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Salehi M, Naseri Nosar M, Amani A, Azami M, Tavakol S, Ghanbari H. Preparation of Pure PLLA, Pure Chitosan, and PLLA/Chitosan Blend Porous Tissue Engineering Scaffolds by Thermally Induced Phase Separation Method and Evaluation of the Corresponding Mechanical and Biological Properties. INT J POLYM MATER PO 2015. [DOI: 10.1080/00914037.2014.1002093] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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86
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Liu WJ, Xu BH, Ye L, Liang D, Wu HL, Zheng YY, Deng JK, Li B, Liu HF. Urinary proteins induce lysosomal membrane permeabilization and lysosomal dysfunction in renal tubular epithelial cells. Am J Physiol Renal Physiol 2015; 308:F639-49. [PMID: 25587119 DOI: 10.1152/ajprenal.00383.2014] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Lysosomal membrane permeabilization (LMP) has been shown to cause the release of cathepsins and other hydrolases from the lysosomal lumen to the cytosol and initiate a cell death pathway. Whether proteinuria triggers LMP in renal tubular epithelial cells (TECs) to accelerate the progression of renal tubulointerstitial injury remains unclear. In the present study, we evaluated TEC injury as well as changes in lysosomal number, volume, activity, and membrane integrity after urinary protein overload in vivo and in vitro. Our results revealed that neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 levels were significantly increased in the urine of patients with minimal change nephrotic syndrome (MCNS) and the culture supernatant of HK-2 cells treated by urinary proteins extracted from MCNS patients. Urinary protein overload also induced apoptotic cell death in HK-2 cells. Importantly, we found that lysosomal volume and number were markedly increased in TECs of patients with MCNS and HK-2 cells overloaded with urinary proteins. However, lysosome function, as assessed by proteolytic degradation of DQ-ovalbumin and cathepsin-B and cathepsin-L activities, was decreased in HK-2 cells overloaded with urinary proteins. Furthermore, urinary protein overload led to a diffuse cytoplasmic immunostaining pattern of cathepsin-B and irregular immunostaining of lysosome-associated membrane protein-1, accompanying a reduction in intracellular acidic components, which could be improved by pretreatment with antioxidant. Taken together, our results indicate that overloading of urinary proteins caused LMP and lysosomal dysfunction at least partly via oxidative stress in TECs.
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Affiliation(s)
- Wei Jing Liu
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
| | - Bi-Hua Xu
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
| | - Lin Ye
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
| | - Dong Liang
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
| | - Hong-Luan Wu
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
| | - Yuan-Yuan Zheng
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
| | - Jian Kun Deng
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
| | - Benyi Li
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
| | - Hua-feng Liu
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China
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87
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Guha S, Coffey EE, Lu W, Lim JC, Beckel JM, Laties AM, Boesze-Battaglia K, Mitchell CH. Approaches for detecting lysosomal alkalinization and impaired degradation in fresh and cultured RPE cells: evidence for a role in retinal degenerations. Exp Eye Res 2014; 126:68-76. [PMID: 25152362 DOI: 10.1016/j.exer.2014.05.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 05/15/2014] [Accepted: 05/18/2014] [Indexed: 01/20/2023]
Abstract
Lysosomes contribute to a multitude of cellular processes, and the pH of the lysosomal lumen plays a central mechanistic role in many of these functions. In addition to controlling the rate of enzymatic degradation for material delivered through autophagic or phagocytotic pathways, lysosomal pH regulates events such as lysosomal fusion with autophagosomes and the release of lysosomal calcium into the cytoplasm. Disruption of either the steady state lysosomal pH or of the regulated manipulations to lysosomal pH may be pathological. For example, chloroquine elevates the lysosomal pH of retinal pigmented epithelial (RPE) cells and triggers a retinopathy characterized by the accumulation of lipofuscin-like material in both humans and animals. Compensatory responses to restore lysosomal pH are observed; new data illustrate that chronic chloroquine treatment increases mRNA expression of the lysosomal/autophagy master transcription factor TcFEB and of the vesicular proton pump vHATPase in the RPE/choroid of mice. An elevated lysosomal pH with upregulation of TcFEB and vHATPase resembles the pathology in fibroblasts of patients with mutant presenilin 1 (PS1), suggesting a common link between age-related macular degeneration (AMD) and Alzheimer's disease. While the absolute rise in pH is often small in these disorders, elevations of only a few tenths of a pH unit can have a major impact on both lysosomal function and the accumulation of waste over decades. Accurate measurement of lysosomal pH can be complex, and imprecise measurements have clouded the field. Protocols to optimize pH measurement from fresh and cultured cells are discussed, and indirect measurements to confirm changes in lysosomal pH and degradative capacity are addressed. The ability of reacidifying treatments to restore degradative function confirms the central role of lysosomal pH in these disorders and identifies potential approaches to treat diseases of lysosomal accumulation like AMD and Alzheimer's disease. In summary, various approaches to determine lysosomal pH in fresh and cultured cells, as well as the potential to restore pH levels to an optimal range, can help identify and repair pathologies associated with lysosomal defects in RPE cells and perhaps also suggest new approaches to treat lysosomal storage diseases throughout the body.
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Affiliation(s)
- Sonia Guha
- Departments of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA; Department of Ophthalmology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Erin E Coffey
- Departments of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Wennan Lu
- Departments of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jason C Lim
- Departments of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jonathan M Beckel
- Departments of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA; Department of Anesthesiology, University of Pittsburgh, USA
| | - Alan M Laties
- Departments of Ophthalmology University of Pennsylvania, Philadelphia, PA, USA
| | | | - Claire H Mitchell
- Departments of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA, USA; Departments of Physiology, University of Pennsylvania, Philadelphia, PA, USA.
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88
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Shubenkov AN, Korovin SB, Andreeva ER, Buravkova LB, Pustovoy VI. Modification of silicon nanoparticle surface with gold or silver attenuates its biocompatibility in vitro. ACTA ACUST UNITED AC 2014. [DOI: 10.1134/s1990519x14050083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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89
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Autophagy as a Possible Underlying Mechanism of Nanomaterial Toxicity. NANOMATERIALS 2014; 4:548-582. [PMID: 28344236 PMCID: PMC5304698 DOI: 10.3390/nano4030548] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 05/23/2014] [Accepted: 06/23/2014] [Indexed: 12/27/2022]
Abstract
The rapid development of nanotechnologies is raising safety concerns because of the potential effects of engineered nanomaterials on human health, particularly at the respiratory level. Since the last decades, many in vivo studies have been interested in the pulmonary effects of different classes of nanomaterials. It has been shown that some of them can induce toxic effects, essentially depending on their physico-chemical characteristics, but other studies did not identify such effects. Inflammation and oxidative stress are currently the two main mechanisms described to explain the observed toxicity. However, the exact underlying mechanism(s) still remain(s) unknown and autophagy could represent an interesting candidate. Autophagy is a physiological process in which cytoplasmic components are digested via a lysosomal pathway. It has been shown that autophagy is involved in the pathogenesis and the progression of human diseases, and is able to modulate the oxidative stress and pro-inflammatory responses. A growing amount of literature suggests that a link between nanomaterial toxicity and autophagy impairment could exist. In this review, we will first summarize what is known about the respiratory effects of nanomaterials and we will then discuss the possible involvement of autophagy in this toxicity. This review should help understand why autophagy impairment could be taken as a promising candidate to fully understand nanomaterials toxicity.
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90
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Arami H, Krishnan KM. Intracellular performance of tailored nanoparticle tracers in magnetic particle imaging. JOURNAL OF APPLIED PHYSICS 2014; 115:17B306. [PMID: 24753632 PMCID: PMC3977802 DOI: 10.1063/1.4867756] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 12/05/2013] [Indexed: 05/17/2023]
Abstract
Magnetic Particle Imaging (MPI) is a quantitative mass-sensitive, tracer-based imaging technique, with potential applications in various cellular imaging applications. The spatial resolution of MPI, in the first approximation, improves by decreasing the full width at half maximum (FWHM) of the field-derivative of the magnetization, dm/dH of the nanoparticle (NP) tracers. The FWHM of dm/dH depends critically on NPs' size, size distribution, and their environment. However, there is limited information on the MPI performance of the NPs after their internalization into cells. In this work, 30 to 150 μg of the iron oxide NPs were incubated in a lysosome-like acidic buffer (0.2 ml, 20 mM citric acid, pH 4.7) and investigated by vibrating sample magnetometry, magnetic particle spectroscopy, transmission electron microscopy, and dynamic light scattering (DLS). The FWHM of the dm/dH curves of the NPs increased with incubation time and buffer to NPs ratio, consistent with a decrease in the median core size of the NPs from ∼20.1 ± 0.98 to ∼18.5 ± 3.15 nm. Further, these smaller degraded NPs formed aggregates that responded to the applied field by hysteretic reversal at higher field values and increased the FWHM. The rate of core size decrease and aggregation were inversely proportional to the concentration of the incubated NPs, due to their slower biodegradation kinetics. The results of this model experiment show that the MPI performance of the NPs in the acidic environments of the intracellular organelles (i.e., lysosomes and endosomes) can be highly dependent on their rate of internalization, residence time, and degradation.
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91
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Koch F, Möller AM, Frenz M, Pieles U, Kuehni-Boghenbor K, Mevissen M. An in vitro toxicity evaluation of gold-, PLLA- and PCL-coated silica nanoparticles in neuronal cells for nanoparticle-assisted laser-tissue soldering. Toxicol In Vitro 2014; 28:990-8. [PMID: 24768613 DOI: 10.1016/j.tiv.2014.04.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/03/2014] [Accepted: 04/14/2014] [Indexed: 12/14/2022]
Abstract
The uptake of silica (Si) and gold (Au) nanoparticles (NPs) engineered for laser-tissue soldering in the brain was investigated using microglial cells and undifferentiated and differentiated SH-SY5Y cells. It is not known what effects NPs elicit once entering the brain. Cellular uptake, cytotoxicity, apoptosis, and the potential induction of oxidative stress by means of depletion of glutathione levels were determined after NP exposure at concentrations of 10(3) and 10(9)NPs/ml. Au-, silica poly (ε-caprolactone) (Si-PCL-) and silica poly-L-lactide (Si-PLLA)-NPs were taken up by all cells investigated. Aggregates and single NPs were found in membrane-surrounded vacuoles and the cytoplasm, but not in the nucleus. Both NP concentrations investigated did not result in cytotoxicity or apoptosis, but reduced glutathione (GSH) levels predominantly at 6 and 24h, but not after 12 h of NP exposure in the microglial cells. NP exposure-induced GSH depletion was concentration-dependent in both cell lines. Si-PCL-NPs induced the strongest effect of GSH depletion followed by Si-PLLA-NPs and Au-NPs. NP size seems to be an important characteristic for this effect. Overall, Au-NPs are most promising for laser-assisted vascular soldering in the brain. Further studies are necessary to further evaluate possible effects of these NPs in neuronal cells.
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Affiliation(s)
- Franziska Koch
- Veterinary Pharmacology & Toxicology, Vetsuisse Faculty University Bern, Länggassstrasse 124, 3012 Bern, Switzerland
| | - Anja-M Möller
- Veterinary Pharmacology & Toxicology, Vetsuisse Faculty University Bern, Länggassstrasse 124, 3012 Bern, Switzerland
| | - Martin Frenz
- Institute of Applied Physics, University Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - Uwe Pieles
- School of Life Sciences, Gruendenstrasse 40, 4132 Muttenz, Switzerland
| | - Kathrin Kuehni-Boghenbor
- Veterinary Anatomy, Vetsuisse Faculty University Bern, Laenggassstrasse 120, 3012 Bern, Switzerland
| | - Meike Mevissen
- Veterinary Pharmacology & Toxicology, Vetsuisse Faculty University Bern, Länggassstrasse 124, 3012 Bern, Switzerland.
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92
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Coffey EE, Beckel JM, Laties AM, Mitchell CH. Lysosomal alkalization and dysfunction in human fibroblasts with the Alzheimer's disease-linked presenilin 1 A246E mutation can be reversed with cAMP. Neuroscience 2014; 263:111-24. [PMID: 24418614 PMCID: PMC4028113 DOI: 10.1016/j.neuroscience.2014.01.001] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 12/30/2013] [Accepted: 01/02/2014] [Indexed: 12/27/2022]
Abstract
Mutation in presenilin 1 (PS1) is one of the leading causes of familial Alzheimer's disease (fAD). PS1 mutation exacerbates the autophagic and lysosomal pathology in AD patients, leading to accumulation of partially degraded material in bloated lysosomes and autophagosomes - a pathology that bears some resemblance to other diseases characterized by elevated lysosomal pH, like age-related macular degeneration. In this study, we examined the effect of the PS1-fAD mutation A246E on lysosomal pH and lysosomal function, and asked whether restoration of lysosomal pH could reverse some of these changes. Lysosomal pH was elevated by 0.2-0.3 pH units in human fibroblasts with the PS1-fAD mutation. The lysosomal alkalization in PS1-fAD fibroblasts was supported by a reduction in the pH-dependent cleavage of cathepsin D and by a reduction in binding of boron-dipyrromethene (BODIPY) FL-pepstatin A to the cathepsin D active site. PS1-fAD cells had increased LC3B-II/-I ratios and p62 levels, consistent with impaired lysosomal degradation and analogous to changes induced by lysosomal alkalinization with chloroquine. PS1-fAD fibroblasts had increased expression of ATP6V1B2, ATG5, BECN1 TFEB mRNA, and of ATP6V1B2, ATG5 and beclin at the protein level, consistent with chronic impairment of autophagic and lysosomal functions in the mutant cells. Critically, cyclic adenosine monophosphate (cAMP) treatment reacidified lysosomal pH in mutant PS1-fAD; cAMP also increased the availability of active cathepsin D and lowered the LC3B-II/-I ratio. These results confirm a small elevation in the lysosomal pH of human PS1-fAD fibroblasts, demonstrate that this lysosomal alkalization is associated with chronic changes in autophagy and degradation, and suggest that treatment to reacidify the lysosomes with cAMP can reverse these changes.
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Affiliation(s)
- E E Coffey
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - J M Beckel
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - A M Laties
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - C H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, United States; Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, United States.
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93
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Beta cyclodextrins bind, stabilize, and remove lipofuscin bisretinoids from retinal pigment epithelium. Proc Natl Acad Sci U S A 2014; 111:E1402-8. [PMID: 24706818 DOI: 10.1073/pnas.1400530111] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Accumulation of lipofuscin bisretinoids (LBs) in the retinal pigment epithelium (RPE) is the alleged cause of retinal degeneration in genetic blinding diseases (e.g., Stargardt) and a possible etiological agent for age-related macular degeneration. Currently, there are no approved treatments for these diseases; hence, agents that efficiently remove LBs from RPE would be valuable therapeutic candidates. Here, we show that beta cyclodextrins (β-CDs) bind LBs and protect them against oxidation. Computer modeling and biochemical data are consistent with the encapsulation of the retinoid arms of LBs within the hydrophobic cavity of β-CD. Importantly, β-CD treatment reduced by 73% and 48% the LB content of RPE cell cultures and of eyecups obtained from Abca4-Rdh8 double knock-out (DKO) mice, respectively. Furthermore, intravitreal administration of β-CDs reduced significantly the content of bisretinoids in the RPE of DKO animals. Thus, our results demonstrate the effectiveness of β-CDs to complex and remove LB deposits from RPE cells and provide crucial data to develop novel prophylactic approaches for retinal disorders elicited by LBs.
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94
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Tetrandrine blocks autophagic flux and induces apoptosis via energetic impairment in cancer cells. Cell Death Dis 2014; 5:e1123. [PMID: 24625982 PMCID: PMC3973245 DOI: 10.1038/cddis.2014.84] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/19/2013] [Accepted: 01/07/2014] [Indexed: 01/01/2023]
Abstract
Lysosomes are acidic organelles that have a crucial role in degrading intracellular macromolecules and organelles during the final stage of autophagy. Tetrandrine (Tet), a bisbenzylisoquinoline alkaloid, was reported as an autophagy activator. Here, in contrast with previous studies, we show that Tet is a potent lysosomal deacidification agent and is able to block autophagic flux in the degradation stage. Single-agent Tet induces significant apoptosis both in vitro and in xenograft models. In the presence of Tet, apoptosis was preceded by a robust accumulation of autophagosomes and an increased level of microtubule-associated protein 1 light chain 3, type II (LC3-II). However, Tet increased the level of sequestosome 1 and decreased the turnover of LC3, indicating the blockade of autophagic flux in the degradation stage. As blockade of autophagic flux decreases the recycling of cellular fuels, Tet reduces the uptake of glucose in cancer cells. These effects lead to insufficient substrates for tricarboxylic acid (TCA) cycle and impaired oxidative phosphorylation. Blunting autophagosome formation using 3-methyladenine or genetic knockdown of Beclin-1 failed to rescue cells upon Tet treatment. By contrast, addition of methyl pyruvate to supplement TCA substrates protected Tet-treated tumor cells. These results demonstrate that energetic impairment is required in Tet-induced apoptosis. Tet, as a potent lysosomal inhibitor, is translatable to the treatment of malignant tumor patients.
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95
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Guha S, Liu J, Baltazar G, Laties AM, Mitchell CH. Rescue of compromised lysosomes enhances degradation of photoreceptor outer segments and reduces lipofuscin-like autofluorescence in retinal pigmented epithelial cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:105-11. [PMID: 24664687 DOI: 10.1007/978-1-4614-3209-8_14] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Healthful cell maintenance requires the efficient degradative processing and removal of waste material. Retinal pigmented epithelial (RPE) cells have the onerous task of degrading both internal cellular debris generated through autophagy as well as phagocytosed photoreceptor outer segments. We propose that the inadequate processing material with the resulting accumulation of cellular waste contributes to the downstream pathologies characterized as age-related macular degeneration (AMD). The lysosomal enzymes responsible for clearance function optimally over a narrow range of acidic pH values; elevation of lysosomal pH by compounds like chloroquine or A2E can impair degradative enzyme activity and lead to a lipofuscin-like autofluorescence. Restoring acidity to the lysosomes of RPE cells can enhance activity of multiple degradative enzymes and is therefore a logical target in early AMD. We have identified several approaches to reacidify lysosomes of compromised RPE cells; stimulation of beta-adrenergic, A2A adenosine and D5 dopamine receptors each lowers lysosomal pH and improves degradation of outer segments. Activation of the CFTR chloride channel also reacidifies lysosomes and increases degradation. These approaches also restore the lysosomal pH of RPE cells from aged ABCA4(-/-) mice with chronically high levels of A2E, suggesting that functional signaling pathways to reacidify lysosomes are retained in aged cells like those in patients with AMD. Acidic nanoparticles transported to RPE lysosomes also lower pH and improve degradation of outer segments. In summary, the ability of diverse approaches to lower lysosomal pH and enhance outer segment degradation support the proposal that lysosomal acidification can prevent the accumulation of lipofuscin-like material in RPE cells.
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Affiliation(s)
- Sonia Guha
- Department of Anatomy and Cell Biology, University of Pennsylvania, 440 Levy Bldg., 240 S. 40th St., 19104, Philadelphia, PA, USA,
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Guha S, Baltazar GC, Coffey EE, Tu LA, Lim JC, Beckel JM, Patel S, Eysteinsson T, Lu W, O'Brien-Jenkins A, Laties AM, Mitchell CH. Lysosomal alkalinization, lipid oxidation, and reduced phagosome clearance triggered by activation of the P2X7 receptor. FASEB J 2013; 27:4500-9. [PMID: 23964074 DOI: 10.1096/fj.13-236166] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lysosomal enzymes function optimally at low pH; as accumulation of waste material contributes to cell aging and disease, dysregulation of lysosomal pH may represent an early step in several pathologies. Here, we demonstrate that stimulation of the P2X7 receptor (P2X7R) for ATP alkalinizes lysosomes in cultured human retinal pigmented epithelial (RPE) cells and impairs lysosomal function. P2X7R stimulation did not kill RPE cells but alkalinized lysosomes by 0.3 U. Receptor stimulation also elevated cytoplasmic Ca(2+); Ca(2+) influx was necessary but not sufficient for lysosomal alkalinization. P2X7R stimulation decreased access to the active site of cathepsin D. Interestingly, lysosomal alkalinization was accompanied by a rise in lipid oxidation that was prevented by P2X7R antagonism. Likewise, the autofluorescence of phagocytosed photoreceptor outer segments increased by lysosomal alkalinization was restored 73% by a P2X7R antagonist. Together, this suggests that endogenous autostimulation of the P2X7R may oxidize lipids and impede clearance. The P2X7R was expressed on apical and basolateral membranes of mouse RPE; mRNA expression of P2X7R and extracellular ATP marker NTPDase1 was raised in RPE tissue from the ABCA4(-/-) mouse model of Stargardt's retinal degeneration. In summary, P2X7R stimulation raises lysosomal pH and impedes lysosomal function, suggesting a possible role for overstimulation in diseases of accumulation.
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Affiliation(s)
- Sonia Guha
- 1Department of Anatomy and Cell Biology, University of Pennsylvania, 440 Levy Bldg., 240 S. 40th St., Philadelphia, PA 19104, USA.
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Kaarniranta K, Sinha D, Blasiak J, Kauppinen A, Veréb Z, Salminen A, Boulton ME, Petrovski G. Autophagy and heterophagy dysregulation leads to retinal pigment epithelium dysfunction and development of age-related macular degeneration. Autophagy 2013; 9:973-84. [PMID: 23590900 PMCID: PMC3722332 DOI: 10.4161/auto.24546] [Citation(s) in RCA: 239] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Age-related macular degeneration (AMD) is a complex, degenerative and progressive eye disease that usually does not lead to complete blindness, but can result in severe loss of central vision. Risk factors for AMD include age, genetics, diet, smoking, oxidative stress and many cardiovascular-associated risk factors. Autophagy is a cellular housekeeping process that removes damaged organelles and protein aggregates, whereas heterophagy, in the case of the retinal pigment epithelium (RPE), is the phagocytosis of exogenous photoreceptor outer segments. Numerous studies have demonstrated that both autophagy and heterophagy are highly active in the RPE. To date, there is increasing evidence that constant oxidative stress impairs autophagy and heterophagy, as well as increases protein aggregation and causes inflammasome activation leading to the pathological phenotype of AMD. This review ties together these crucial pathological topics and reflects upon autophagy as a potential therapeutic target in AMD.
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Affiliation(s)
- Kai Kaarniranta
- Department of Ophthalmology; Institute of Clinical Medicine; University of Eastern Finland; Kuopio, Finland; Department of Ophthalmology; Kuopio University Hospital; Kuopio, Finland
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98
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Petrukhin K. Pharmacological inhibition of lipofuscin accumulation in the retina as a therapeutic strategy for dry AMD treatment. ACTA ACUST UNITED AC 2013; 10:e11-e20. [PMID: 25152755 DOI: 10.1016/j.ddstr.2013.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in the western world. There is no FDA-approved treatment for the most prevalent dry (atrophic) form of AMD. Photoreceptor degeneration in dry AMD is triggered by abnormalities in the retinal pigment epithelium (RPE). It has been suggested that excessive accumulation of fluorescent lipofuscin pigment in the RPE represents an important pathogenic factor in etiology and progression of dry AMD. Cytotoxic lipofuscin bisretinoids, such as A2E, are formed in the retina in a non-enzymatic way from visual cycle retinoids. Inhibition of toxic bisretinoid production in the retina seems to be a sound treatment strategy for dry AMD. In this review we discuss the following classes of pharmacological treatments inhibiting lipofuscin bisretinoid formation in the retina: direct inhibitors of key visual cycle enzymes, RBP4 antagonists, primary amine-containing aldehyde traps, and deuterated analogs of vitamin A.
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