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Prieto K, Arévalo C, Lasso P, Carlosama C, Urueña C, Fiorentino S, Barreto A. Plant extracts modulate cellular stress to inhibit replication of mouse Coronavirus MHV-A59. Heliyon 2024; 10:e23403. [PMID: 38169850 PMCID: PMC10758815 DOI: 10.1016/j.heliyon.2023.e23403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 11/14/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
The Covid-19 infection outbreak led to a global epidemic, and although several vaccines have been developed, the appearance of mutations has allowed the virus to evade the immune response. Added to this is the existing risk of the appearance of new emerging viruses. Therefore, it is necessary to explore novel antiviral therapies. Here, we investigate the potential in vitro of plant extracts to modulate cellular stress and inhibit murine hepatitis virus (MHV)-A59 replication. L929 cells were treated with P2Et (Caesalpinia spinosa) and Anamu SC (Petiveria alliacea) plant extracts during infection and virus production, ROS (reactive oxygen species), UPR (unfolded protein response), and autophagy were assessed. P2Et inhibited virus replication and attenuated both ROS production and UPR activation induced during infection. In contrast, the sustained presence of Anamu SC during viral adsorption and replication was required to inhibit viral infection, tending to induce pro-oxidant effects, and increasing UPR gene expression. Notably, the loss of the PERK protein resulted in a slight decrease in virus yield, suggesting a potential involvement of this UPR pathway during replication. Intriguingly, both extracts either maintained or increased the calreticulin surface exposure induced during infection. In conclusion, our findings highlight the development of antiviral natural plant extracts that differentially modulate cellular stress.
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Affiliation(s)
| | | | - Paola Lasso
- Grupo de Inmunobiología y Biología Celular, Departamento de Microbiología, Pontificia Universidad Javeriana. Bogotá, Colombia
| | - Carolina Carlosama
- Grupo de Inmunobiología y Biología Celular, Departamento de Microbiología, Pontificia Universidad Javeriana. Bogotá, Colombia
| | - Claudia Urueña
- Grupo de Inmunobiología y Biología Celular, Departamento de Microbiología, Pontificia Universidad Javeriana. Bogotá, Colombia
| | - Susana Fiorentino
- Grupo de Inmunobiología y Biología Celular, Departamento de Microbiología, Pontificia Universidad Javeriana. Bogotá, Colombia
| | - Alfonso Barreto
- Grupo de Inmunobiología y Biología Celular, Departamento de Microbiología, Pontificia Universidad Javeriana. Bogotá, Colombia
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2
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Chen G, Wei T, Ju F, Li H. Protein quality control and aggregation in the endoplasmic reticulum: From basic to bedside. Front Cell Dev Biol 2023; 11:1156152. [PMID: 37152279 PMCID: PMC10154544 DOI: 10.3389/fcell.2023.1156152] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/10/2023] [Indexed: 05/09/2023] Open
Abstract
Endoplasmic reticulum (ER) is the largest membrane-bound compartment in all cells and functions as a key regulator in protein biosynthesis, lipid metabolism, and calcium balance. Mammalian endoplasmic reticulum has evolved with an orchestrated protein quality control system to handle defective proteins and ensure endoplasmic reticulum homeostasis. Nevertheless, the accumulation and aggregation of misfolded proteins in the endoplasmic reticulum may occur during pathological conditions. The inability of endoplasmic reticulum quality control system to clear faulty proteins and aggregates from the endoplasmic reticulum results in the development of many human disorders. The efforts to comprehensively understand endoplasmic reticulum quality control network and protein aggregation will benefit the diagnostics and therapeutics of endoplasmic reticulum storage diseases. Herein, we overview recent advances in mammalian endoplasmic reticulum protein quality control system, describe protein phase transition model, and summarize the approaches to monitor protein aggregation. Moreover, we discuss the therapeutic applications of enhancing endoplasmic reticulum protein quality control pathways in endoplasmic reticulum storage diseases.
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Affiliation(s)
- Guofang Chen
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Tingyi Wei
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Furong Ju
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Sha Tin, Hong kong SAR, China
| | - Haisen Li
- School of Life Sciences, Fudan University, Shanghai, China
- AoBio Medical, Shanghai, China
- *Correspondence: Haisen Li,
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3
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Mir S, Golden BDO, Griess BJ, Vengoji R, Tom E, Kosmacek EA, Oberley-Deegan RE, Talmon GA, Band V, Teoh-Fitzgerald ML. Upregulation of Nox4 induces a pro-survival Nrf2 response in cancer-associated fibroblasts that promotes tumorigenesis and metastasis, in part via Birc5 induction. Breast Cancer Res 2022; 24:48. [PMID: 35836253 PMCID: PMC9281082 DOI: 10.1186/s13058-022-01548-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/30/2022] [Indexed: 04/12/2023] Open
Abstract
BACKGROUND A pro-oxidant enzyme, NADPH oxidase 4 (Nox4) has been reported to be a critical downstream effector of TGFβ-induced myofibroblast transformation during fibrosis. While there are a small number of studies suggesting an oncogenic role of Nox4 derived from activated fibroblasts, direct evidence linking this pro-oxidant to the tumor-supporting CAF phenotype and the mechanisms involved are lacking, particularly in breast cancer. METHODS We targeted Nox4 in breast patient-derived CAFs via siRNA-mediated knockdown or administration of a pharmaceutical inhibitor (GKT137831). We also determine primary tumor growth and metastasis of implanted tumor cells using a stable Nox4-/- syngeneic mouse model. Autophagic flux of CAFs was assessed using a tandem fluorescent-tagged ptfl-LC3 plasmid via confocal microscopy analysis and determination of the expression level of autophagy markers (beclin-1 and LC3B). Nox4 overexpressing CAFs depend on the Nrf2 (nuclear factor-erythroid factor 2-related factor 2) pathway for survival. We then determined the dependency of Nox4-overexpressing CAFs on the Nrf2-mediated adaptive stress response pathway for survival. Furthermore, we investigated the involvement of Birc5 on CAF phenotype (viability and collagen contraction activity) as well as the expression level of CAF markers, FAP and αSMA. CONCLUSIONS We found that deletion of stroma Nox4 and pharmaceutically targeting its activity with GKT137831 significantly inhibited orthotopic tumor growth and metastasis of implanted E0771 and 4T1 murine mammary carcinoma cell lines in mice. More importantly, we found a significant upregulation of Nox4 expression in CAFs isolated from human breast tumors versus normal mammary fibroblasts (RMFs). Our in situ RNA hybridization analysis for Nox4 transcription on a human breast tumor microarray further support a role of this pro-oxidant in the stroma of breast carcinomas. In addition, we found that Nox4 promotes autophagy in CAFs. Moreover, we found that Nox4 promoted survival of CAFs via activation of Nrf2, a master regulator of oxidative stress response. We have further shown Birc5 is involved as a downstream modulator of Nrf2-mediated pro-survival phenotype. Together these studies indicate a role of redox signaling via the Nox4-Nrf2 pathway in tumorigenesis and metastasis of breast cancer cells by promoting autophagy and survival of CAFs.
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Affiliation(s)
- Shakeel Mir
- Department of Biochemistry and Molecular Biology, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, 7005 Durham Research Center, 985870 Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Briana D Ormsbee Golden
- Department of Biochemistry and Molecular Biology, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, 7005 Durham Research Center, 985870 Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Brandon J Griess
- Department of Biochemistry and Molecular Biology, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, 7005 Durham Research Center, 985870 Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Raghupathy Vengoji
- Department of Biochemistry and Molecular Biology, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, 7005 Durham Research Center, 985870 Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Eric Tom
- Department of Biochemistry and Molecular Biology, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, 7005 Durham Research Center, 985870 Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Elizabeth A Kosmacek
- Department of Biochemistry and Molecular Biology, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, 7005 Durham Research Center, 985870 Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Rebecca E Oberley-Deegan
- Department of Biochemistry and Molecular Biology, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, 7005 Durham Research Center, 985870 Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Geoffrey A Talmon
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Vimla Band
- Department of Genetics, Cell Biology and Anatomy, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Melissa Lt Teoh-Fitzgerald
- Department of Biochemistry and Molecular Biology, Buffett Cancer Center, College of Medicine, University of Nebraska Medical Center, 7005 Durham Research Center, 985870 Nebraska Medical Center, Omaha, NE, 68198, USA.
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4
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Morales I, Puertas-Avendaño R, Sanchez A, Perez-Barreto A, Rodriguez-Sabate C, Rodriguez M. Astrocytes and retrograde degeneration of nigrostriatal dopaminergic neurons in Parkinson's disease: removing axonal debris. Transl Neurodegener 2021; 10:43. [PMID: 34727977 PMCID: PMC8562009 DOI: 10.1186/s40035-021-00262-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 09/05/2021] [Indexed: 12/26/2022] Open
Abstract
Objective The dopaminergic nigrostriatal neurons (DA cells) in healthy people present a slow degeneration with aging, which produces cellular debris throughout life. About 2%–5% of people present rapid cell degeneration of more than 50% of DA cells, which produces Parkinson’s disease (PD). Neuroinflammation accelerates the cell degeneration and may be critical for the transition between the slow physiological and the rapid pathological degeneration of DA cells, particularly when it activates microglial cells of the medial forebrain bundle near dopaminergic axons. As synaptic debris produced by DA cell degeneration may trigger the parkinsonian neuroinflammation, this study investigated the removal of axonal debris produced by retrograde degeneration of DA cells, paying particular attention to the relative roles of astrocytes and microglia. Methods Rats and mice were injected in the lateral ventricles with 6-hydroxydopamine, inducing a degeneration of dopaminergic synapses in the striatum which was not accompanied by non-selective tissue damage, microgliosis or neuroinflammation. The possible retrograde degeneration of dopaminergic axons, and the production and metabolization of DA-cell debris were studied with immunohistochemical methods and analyzed in confocal and electron microscopy images. Results The selective degeneration of dopaminergic synapses in the striatum was followed by a retrograde degeneration of dopaminergic axons whose debris was found within spheroids of the medial forebrain bundle. These spheroids retained mitochondria and most (e.g., tyrosine hydroxylase, the dopamine transporter protein, and amyloid precursor protein) but not all (e.g., α-synuclein) proteins of the degenerating dopaminergic axons. Spheroids showed initial (autophagosomes) but not late (lysosomes) components of autophagy (incomplete autophagy). These spheroids were penetrated by astrocytic processes of the medial forebrain bundle, which provided the lysosomes needed to continue the degradation of dopaminergic debris. Finally, dopaminergic proteins were observed in the cell somata of astrocytes. No microgliosis or microglial phagocytosis of debris was observed in the medial forebrain bundle during the retrograde degeneration of dopaminergic axons. Conclusions The present data suggest a physiological role of astrocytic phagocytosis of axonal debris for the medial forebrain bundle astrocytes, which may prevent the activation of microglia and the spread of retrograde axonal degeneration in PD. Supplementary Information The online version contains supplementary material available at 10.1186/s40035-021-00262-1.
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Affiliation(s)
- Ingrid Morales
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Faculty of Medicine, La Laguna University, La Laguna, Tenerife, Canary Islands, Spain.,Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED) , Madrid, Spain
| | - Ricardo Puertas-Avendaño
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Faculty of Medicine, La Laguna University, La Laguna, Tenerife, Canary Islands, Spain
| | - Alberto Sanchez
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Faculty of Medicine, La Laguna University, La Laguna, Tenerife, Canary Islands, Spain.,Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED) , Madrid, Spain
| | - Adrian Perez-Barreto
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Faculty of Medicine, La Laguna University, La Laguna, Tenerife, Canary Islands, Spain
| | - Clara Rodriguez-Sabate
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED) , Madrid, Spain
| | - Manuel Rodriguez
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Faculty of Medicine, La Laguna University, La Laguna, Tenerife, Canary Islands, Spain. .,Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED) , Madrid, Spain.
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5
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Cornell J, Salinas S, Huang HY, Zhou M. Microglia regulation of synaptic plasticity and learning and memory. Neural Regen Res 2021; 17:705-716. [PMID: 34472455 PMCID: PMC8530121 DOI: 10.4103/1673-5374.322423] [Citation(s) in RCA: 142] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Microglia are the resident macrophages of the central nervous system. Microglia possess varied morphologies and functions. Under normal physiological conditions, microglia mainly exist in a resting state and constantly monitor their microenvironment and survey neuronal and synaptic activity. Through the C1q, C3 and CR3 “Eat Me” and CD47 and SIRPα “Don’t Eat Me” complement pathways, as well as other pathways such as CX3CR1 signaling, resting microglia regulate synaptic pruning, a process crucial for the promotion of synapse formation and the regulation of neuronal activity and synaptic plasticity. By mediating synaptic pruning, resting microglia play an important role in the regulation of experience-dependent plasticity in the barrel cortex and visual cortex after whisker removal or monocular deprivation, and also in the regulation of learning and memory, including the modulation of memory strength, forgetfulness, and memory quality. As a response to brain injury, infection or neuroinflammation, microglia become activated and increase in number. Activated microglia change to an amoeboid shape, migrate to sites of inflammation and secrete proteins such as cytokines, chemokines and reactive oxygen species. These molecules released by microglia can lead to synaptic plasticity and learning and memory deficits associated with aging, Alzheimer’s disease, traumatic brain injury, HIV-associated neurocognitive disorder, and other neurological or mental disorders such as autism, depression and post-traumatic stress disorder. With a focus mainly on recently published literature, here we reviewed the studies investigating the role of resting microglia in synaptic plasticity and learning and memory, as well as how activated microglia modulate disease-related plasticity and learning and memory deficits. By summarizing the function of microglia in these processes, we aim to provide an overview of microglia regulation of synaptic plasticity and learning and memory, and to discuss the possibility of microglia manipulation as a therapeutic to ameliorate cognitive deficits associated with aging, Alzheimer’s disease, traumatic brain injury, HIV-associated neurocognitive disorder, and mental disorders.
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Affiliation(s)
- Jessica Cornell
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
| | - Shelbi Salinas
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
| | - Hou-Yuan Huang
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
| | - Miou Zhou
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, USA
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6
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Li Z, Ma J, Kuang Z, Jiang Y. β-Asarone Attenuates Aβ-Induced Neuronal Damage in PC12 Cells Overexpressing APPswe by Restoring Autophagic Flux. Front Pharmacol 2021; 12:701635. [PMID: 34393783 PMCID: PMC8355419 DOI: 10.3389/fphar.2021.701635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 07/19/2021] [Indexed: 11/29/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive memory damage and cognitive dysfunction. Studies have shown that defective autophagic flux is associated with neuronal dysfunction. Modulating autophagic activity represents a potential method of combating AD. In Chinese medicine, Acori Tatarinowii Rhizoma is used to treat dementia and amnesia. β-Asarone, an active component of this rhizome can protect PC12 cells from Aβ-induced injury and modulate expression of autophagy factors. However, its cytoprotective mechanisms have yet to be discerned. It is unclear whether β-asarone affects autophagic flux and, if it does, whether this effect can alleviate Aβ cell damage. In the present study, we constructed APPswe-overexpressing PC12 cell line as a cell model of Aβ-induced damage and assessed expression of autophagic flux-related proteins as well as the number and morphology of autophagosomes and autolysosomes. Our results show that β-asarone decreases the expression levels of Beclin-1, p62, LC3-Ⅱ, and Aβ1-42. β-Asarone reduced the number of autophagosomes and increased the number of autolysosomes, as determined by confocal laser scanning microscopy and transmission electron microscopy. Our results suggest that β-asarone can protect PC12 cells from Aβ-induced damage by promoting autophagic flux, which may be achieved by enhancing autophagosome-lysosome fusion and/or lysosome function.
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Affiliation(s)
- Zhenwan Li
- The First Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jin Ma
- The First Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhongsheng Kuang
- The First Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yong Jiang
- The First Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, China
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7
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Yang Y, Wu Y, Zou J, Wang YH, Xu MX, Huang W, Yu DJ, Zhang L, Zhang YY, Sun XD. Naringenin Attenuates Non-Alcoholic Fatty Liver Disease by Enhancing Energy Expenditure and Regulating Autophagy via AMPK. Front Pharmacol 2021; 12:687095. [PMID: 34163366 PMCID: PMC8215389 DOI: 10.3389/fphar.2021.687095] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 05/19/2021] [Indexed: 12/11/2022] Open
Abstract
Background: The prevalence of non-alcoholic fatty liver disease (NAFLD) keeps growing recently. Purpose: To investigate the effects and mechanisms of naringenin (NAR) on NAFLD. Methods: High-fat diet (HFD)-induced NAFLD rats were orally administered with NAR at 10, 30, and 90 mg/kg for 2 weeks. The serum level of triglyceride (TG), total cholesterol (TC), glutamic-oxaloacetic transaminase (AST), and glutamic-pyruvic transaminase (ALT) was measured. The hepatic histology was detected by H&E and oil red O staining. L02 and Huh-7 cells were induced by sodium oleate to establish a NAFLD cell model. The effects of NAR on lipid accumulation were detected by oil red O staining. The glucose uptake and ATP content of 3T3-L1 adipocytes and C2C12 myotubes were measured. The expression of proteins of the AMPK signaling pathway in 3T3-L1 adipocytes and C2C12 myotubes was assessed by Western blotting. The mitochondrial biogenesis of 3T3-L1 adipocytes and C2C12 myotubes was measured by mitotracker orange staining and Western blotting. The biomarkers of autophagy were detected by Western blotting and immunofluorescence. The binding of NAR to AMPKγ1 was analyzed by molecular docking. Chloroquine and compound C were employed to block autophagic flux and AMPK, respectively. Results: NAR alleviated HFD-induced NAFLD in rats at 10, 30, and 90 mg/kg. NAR attenuated lipid accumulation in L02 and Huh-7 cells at 0.7, 2.2, 6.7, and 20 μM. NAR increased glucose uptake, decreased the ATP content, activated the CaMKKβ/AMPK/ACC pathway, and enhanced the mitochondrial biogenesis in 3T3-L1 adipocytes and C2C12 myotubes. NAR increased autophagy and promoted the initiation of autophagic flux in 3T3-L1 preadipocytes and C2C12 myoblasts, while it inhibited autophagy in NAFLD rats, 3T3-L1 adipocytes, and C2C12 myotubes. Molecular docking showed that NAR binds to AMPKγ1. Compound C blocked effects of NAR on lipid accumulation and autophagy in L02 cells. Conclusion: NAR alleviates NAFLD by increasing energy expenditure and regulating autophagy via activating AMPK directly and indirectly. The direct binding of NAR and AMPKγ1 needs further validation.
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Affiliation(s)
- Ying Yang
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China
| | - Yue Wu
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China
| | - Jie Zou
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China
| | - Yu-Hao Wang
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China
| | - Meng-Xia Xu
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China
| | - Wei Huang
- Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Dao-Jiang Yu
- Department of Plastic Surgery, The Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, China
| | - Li Zhang
- Analytical and Testing Center, Sichuan University, Chengdu, China
| | - Yuan-Yuan Zhang
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China.,Department of Endocrinology, Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Xiao-Dong Sun
- West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, China.,Department of Plastic Surgery, The Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, China
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8
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Lee YS, Gupta DP, Park SH, Yang HJ, Song GJ. Anti-Inflammatory Effects of Dimethyl Fumarate in Microglia via an Autophagy Dependent Pathway. Front Pharmacol 2021; 12:612981. [PMID: 34025399 PMCID: PMC8137969 DOI: 10.3389/fphar.2021.612981] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 04/19/2021] [Indexed: 01/22/2023] Open
Abstract
Dimethyl fumarate (DMF), which has been approved by the Food and Drug Administration for the treatment of relapsing-remitting multiple sclerosis, is considered to exert anti-inflammatory and antioxidant effects. Microglia maintain homeostasis in the central nervous system and play a key role in neuroinflammation, while autophagy controls numerous fundamental biological processes, including pathogen removal, cytokine production, and clearance of toxic aggregates. However, the role of DMF in autophagy induction and the relationship of this effect with its anti-inflammatory functions in microglia are not well known. In the present study, we investigated whether DMF inhibited neuroinflammation and induced autophagy in microglia. First, we confirmed the anti-neuroinflammatory effect of DMF in mice with streptozotocin-induced diabetic neuropathy. Next, we used in vitro models including microglial cell lines and primary microglial cells to examine the anti-inflammatory and neuroprotective effects of DMF. We found that DMF significantly inhibited nitric oxide and proinflammatory cytokine production in lipopolysaccharide-stimulated microglia and induced the switch of microglia to the M2 state. In addition, DMF treatment increased the expression levels of autophagy markers including microtubule-associated protein light chain 3 (LC3) and autophagy-related protein 7 (ATG7) and the formation of LC3 puncta in microglia. The anti-inflammatory effect of DMF in microglia was significantly reduced by pretreatment with autophagy inhibitors. These data suggest that DMF leads to the induction of autophagy in microglia and that its anti-inflammatory effects are partially mediated through an autophagy-dependent pathway.
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Affiliation(s)
- Young-Sun Lee
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Gangneung, Korea.,Translational Brain Research Center, International St. Mary's Hospital, Catholic Kwandong University, Incheon, Korea
| | - Deepak Prasad Gupta
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Gangneung, Korea
| | - Sung Hee Park
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Gangneung, Korea
| | - Hyun-Jeong Yang
- Department of Integrative Biosciences, University of Brain Education, Cheonan, Korea
| | - Gyun Jee Song
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Gangneung, Korea.,Translational Brain Research Center, International St. Mary's Hospital, Catholic Kwandong University, Incheon, Korea
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9
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Carino A, Marchianò S, Biagioli M, Scarpelli P, Bordoni M, Di Giorgio C, Roselli R, Fiorucci C, Monti MC, Distrutti E, Zampella A, Fiorucci S. The bile acid activated receptors GPBAR1 and FXR exert antagonistic effects on autophagy. FASEB J 2020; 35:e21271. [DOI: 10.1096/fj.202001386r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 11/11/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Adriana Carino
- Department of Surgical and Biomedical Sciences University of Perugia Perugia Italy
| | - Silvia Marchianò
- Department of Surgical and Biomedical Sciences University of Perugia Perugia Italy
| | - Michele Biagioli
- Department of Surgical and Biomedical Sciences University of Perugia Perugia Italy
| | | | - Martina Bordoni
- Department of Surgical and Biomedical Sciences University of Perugia Perugia Italy
| | - Cristina Di Giorgio
- Department of Surgical and Biomedical Sciences University of Perugia Perugia Italy
| | - Rosalinda Roselli
- Department of Pharmacy University of Naples Federico II Naples Italy
| | - Chiara Fiorucci
- Department of Surgical and Biomedical Sciences University of Perugia Perugia Italy
| | | | - Eleonora Distrutti
- SC di Gastroenterologia ed Epatologia Azienda Ospedaliera di Perugia Perugia Italy
| | - Angela Zampella
- Department of Pharmacy University of Naples Federico II Naples Italy
| | - Stefano Fiorucci
- Department of Surgical and Biomedical Sciences University of Perugia Perugia Italy
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10
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Morales I, Sanchez A, Puertas-Avendaño R, Rodriguez-Sabate C, Perez-Barreto A, Rodriguez M. Neuroglial transmitophagy and Parkinson's disease. Glia 2020; 68:2277-2299. [PMID: 32415886 DOI: 10.1002/glia.23839] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/17/2020] [Accepted: 04/21/2020] [Indexed: 12/28/2022]
Abstract
Mitophagy is essential for the health of dopaminergic neurons because mitochondrial damage is a keystone of Parkinson's disease. The aim of the present work was to study the degradation of mitochondria in the degenerating dopaminergic synapse. Adult Sprague-Dawley rats and YFP-Mito-DAn mice with fluorescent mitochondria in dopaminergic neurons were injected in the lateral ventricles with 6-hydroxydopamine, a toxic that inhibits the mitochondrial chain of dopaminergic neurons and blockades the axonal transport. Dopaminergic terminals closest to the lateral ventricle showed an axonal fragmentation and an accumulation of damaged mitochondria in 2-9 μ saccular structures (spheroids). Damaged mitochondria accumulated in spheroids initiated (showing high Pink1, parkin, ubiquitin, p-S65-Ubi, AMBRA1, and BCL2L13 immunoreactivity and developing autophagosomes) but did not complete (mitochondria were not polyubiquitinated, autophagosomes had no STX17, and no lysosomes were found in spheroids) the mitophagy process. Then, spheroids were penetrated by astrocytic processes and DAergic mitochondria were transferred to astrocytes where they were polyubiquitinated (UbiK63+) and linked to mature autophagosomes (STX17+) which became autophagolysosomes (Lamp1/Lamp2 which co-localized with LC3). Present data provide evidence that the mitophagy of degenerating dopaminergic terminals starts in the dopaminergic spheroids and finishes in the surrounding astrocytes (spheroid-mediated transmitophagy). The neuron-astrocyte transmitophagy could be critical for preventing the release of damaged mitochondria to the extracellular medium and the neuro-inflammatory activity which characterizes Parkinson's disease.
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Affiliation(s)
- Ingrid Morales
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, La Laguna University, La Laguna, Tenerife, Spain.,Center for Networked Biomedical Research in Neurodegenerative Diseases, Madrid, Spain
| | - Alberto Sanchez
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, La Laguna University, La Laguna, Tenerife, Spain
| | - Ricardo Puertas-Avendaño
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, La Laguna University, La Laguna, Tenerife, Spain
| | | | - Adrian Perez-Barreto
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, La Laguna University, La Laguna, Tenerife, Spain
| | - Manuel Rodriguez
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, La Laguna University, La Laguna, Tenerife, Spain.,Center for Networked Biomedical Research in Neurodegenerative Diseases, Madrid, Spain
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11
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Liu J, Wang X, Zheng M, Luan Q. Lipopolysaccharide from Porphyromonas gingivalis promotes autophagy of human gingival fibroblasts through the PI3K/Akt/mTOR signaling pathway. Life Sci 2018; 211:133-139. [DOI: 10.1016/j.lfs.2018.09.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 08/28/2018] [Accepted: 09/11/2018] [Indexed: 12/31/2022]
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12
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Duan S. Silencing the autophagy-specific gene Beclin-1 contributes to attenuated hypoxia-induced vasculogenic mimicry formation in glioma. Cancer Biomark 2018; 21:565-574. [PMID: 29278874 DOI: 10.3233/cbm-170444] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To explore the influence of Beclin-1 on vasculogenic mimicry (VM) induced by hypoxia in glioma. METHODS CD34-PAS staining was carried out to observe VM formation, and immunohistochemistry was used to determine the expression levels of Beclin-1, HIF-1α, VEGF and MMP2 in 105 patients with primary glioma. Human glioma U87MG cells were divided into Normoxia, Hypoxia, Hypoxia + NC siRNA and Hypoxia + Beclin-1 siRNA groups. Cobalt chloride (CoCl2) was used to stimulate hypoxic conditions, and a VM tube formation assay was used to detect VM formation. Wound healing and Transwell invasion assays were used to detect the invasive and migratory abilities of U87MG cells, respectively. Fluorescent LC3 puncta analysis was performed to examine the status of autophagic flux. Expression levels of Beclin-1 and VM-related molecules were determined using real-time quantitative-polymerase chain reaction (RT-qPCR) and western blotting. RESULTS There were 34 VM-positive cases and 71 VM-negative cases among 105 glioma patients, and VM formation was correlated with pathological grade and the expression of Beclin-1, HIF-1α, VEGF and MMP2. Positive relations were found between Beclin-1 and the expression of HIF-1α, VEGF and MMP2. Under hypoxic conditions, significant increases in the total length of tubes, migration rate, invasion cell number and expression of VM-related molecules were found in U87MG cells. Silencing Beclin-1 markedly decreased hypoxia-induced VM formation and the invasive and migratory abilities, together with the expression of VM-related molecules, in U87MG cells and significantly inhibited the autophagic flux. CONCLUSION Silencing Beclin-1 can attenuate hypoxia-induced VM formation and the metastatic ability of U87MG cells and is a potential target for VM inhibition in glioma.
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13
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Yin S, Yang S, Pan X, Ma A, Ma J, Pei H, Dong Y, Li S, Li W, Bi X. MicroRNA‑155 promotes ox‑LDL‑induced autophagy in human umbilical vein endothelial cells by targeting the PI3K/Akt/mTOR pathway. Mol Med Rep 2018; 18:2798-2806. [PMID: 30015881 PMCID: PMC6102700 DOI: 10.3892/mmr.2018.9236] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 06/07/2018] [Indexed: 12/12/2022] Open
Abstract
Endothelial cell autophagy has a protective role in inhibiting inflammation and preventing the development of atherosclerosis, which may be regulated by microRNA (miR)-155. The present study aimed to investigate the mechanisms of autophagy in the development of atherosclerosis. Human umbilical vein endothelial cells model in vitro and using oxidized low-density lipoprotein (ox-LDL) stimulated cells to simulate the atherosclerosis. MiR-155 mimics, miR-155 inhibitors, and a negative control were respectively transfected in human umbilical vein endothelial cells to analyzed alterations in the expression of miR-155. It was demonstrated that overexpression of miR-155 promoted autophagic activity in oxidized low-density lipoprotein-stimulated human umbilical vein endothelial cells, whereas inhibition of the expression of miR-155 reduced autophagic activity. Overexpression of miR-155 revealed that it regulated autophagy via the phosphatidylinositol-3 kinase (PI3K)/RAC-α serine/threonine-protein kinase (Akt)/mechanistic target of rapamycin pathway (mTOR) signaling pathway. A luciferase reporter assay demonstrated that miR-155 directly bound to the PI3K catalytic subunit a and Ras homolog enriched in brain 3′-untranslated region and inhibited its luciferase activity. Therefore, the results of the present study suggested that miR-155 promoted autophagy in vascular endothelial cells and that this may have occurred via targeting of the PI3K/Akt/mTOR pathway. Thus, miR-155 may be considered as a potential therapeutic target for the treatment of atherosclerosis.
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Affiliation(s)
- Shuangshuang Yin
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Shaonan Yang
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Xudong Pan
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Aijun Ma
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Juanjuan Ma
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Haotian Pei
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Yi Dong
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Shu Li
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Wei Li
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Xinran Bi
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
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14
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Gao F, Su Q, Yang W, Pang S, Wang S, Cui Y, Zhang J, Yan B. Functional variants in the LC3B gene promoter in acute myocardial infarction. J Cell Biochem 2018; 119:7339-7349. [PMID: 29761913 DOI: 10.1002/jcb.27035] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 04/05/2018] [Indexed: 11/07/2022]
Abstract
Acute myocardial infarction (AMI) is a common disease mainly caused by atherosclerosis, for which genetic causes remain largely unknown. Recently, low frequency and rare genetic variants have been proposed as risk factors. Autophagy has been involved in many cellular processes, such as lipid metabolism and inflammation, and implicated in human diseases, including cardiovascular diseases. In previous studies, we have reported reduced levels of LC3B, a core protein and a marker for autophagy, in AMI patients. In this study, the LC3B gene promoter was genetically and functionally analyzed in large cohorts of AMI patients (n = 383) and healthy controls (n = 390). A total of 25 DNA sequence variants (DSVs) including SNPs were found. Seven DSVs and three SNPs were only identified in AMI patients. All the DSVs and SNPs (except one) significantly decreased the transcriptional activity of the LC3B gene promoter in both HEK-293 and H9c2 cells (P < 0.05). Further electrophoretic mobility shift assay suggested that the DSVs affected the binding of transcription factors. In contrast, the DSVs and SNPs found only in controls or in both AMI patients and controls did not significantly affected LC3B gene promoter activity (P > 0.05). Therefore, our data suggested that the DSVs identified in AMI patients may change LC3B level by affecting the transcriptional activity of LC3B gene promoter, contributing to the AMI development. Upregulation of the LC3B gene expression may provide a novel and potential therapy for AMI patients.
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Affiliation(s)
- Feng Gao
- Department of Medicine, Shandong University School of Medicine, Jinan, Shandong, China
| | - Qiang Su
- Department of Medicine, Shandong University School of Medicine, Jinan, Shandong, China
| | - Wentao Yang
- Department of Medicine, Shandong University School of Medicine, Jinan, Shandong, China
| | - Shuchao Pang
- Shandong Provincial Key Laboratory of Cardiac Disease Diagnosis and Treatment, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China
| | - Shuai Wang
- Department of Medicine, Shandong University School of Medicine, Jinan, Shandong, China
| | - Yinghua Cui
- Division of Cardiology, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China.,The Center for Molecular Genetics of Cardiovascular Diseases, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China
| | - Jinguo Zhang
- Division of Cardiology, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China.,The Center for Molecular Genetics of Cardiovascular Diseases, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China
| | - Bo Yan
- Shandong Provincial Key Laboratory of Cardiac Disease Diagnosis and Treatment, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China.,The Center for Molecular Genetics of Cardiovascular Diseases, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China.,Shandong Provincial Sino-US Cooperation Research Center for Translational Medicine, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, Shandong, China
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15
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Zhang YS, Wang F, Cui SX, Qu XJ. Natural dietary compound naringin prevents azoxymethane/dextran sodium sulfate-induced chronic colorectal inflammation and carcinogenesis in mice. Cancer Biol Ther 2018; 19:735-744. [PMID: 29580144 DOI: 10.1080/15384047.2018.1453971] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Naringin, a natural occurring flavonoid compound, enriches in citrus fruits. We aimed to evaluate the inhibitory effect of naringin on colitis and chronic inflammation-driven carcinogenesis. Male C57BL/6 mice were exposed to AOM/DSS to induce colorectal inflammation and carcinogenesis. Naringin by oral administration prevented AOM/DSS-induced ulcerative colitis and carcinogenesis without significant side effects. Naringin attenuated the severity of colitis and colorectal adenomas through inhibiting myeloid-derived suppressor cells (MDSCs), pro-inflammatory mediators GM-CSF/M-CSF, IL-6 and TNF-α and the NF-κB/IL-6/STAT3 cascades in colorectal tissues. Naringin-treated mice exhibited normalized structures of colorectal tissues. Electron microscopy analysis showed the suppression of robust endoplasmic reticulum (ER) stress-induced autophagy. Naringin inhibited the secretion of the ER-spanning transmembrane proteins, such as GRP78 ATF6, IRE1α and activated PERK phosphorylated eIF-2α and complex of autophagosomes ATG3, ATG5, ATG7, ATG12, ATG16 and ATG16L1 in the colorectal mucosal cells. CONCLUSION Naringin prevented colitis and colorectal carcinogenesis through suppressing robust ER stress-induced autophagy in colorectal mucosal cells. Naringin could develop a promising therapeutic agent for the prevention of ulcerative colitis and colorectal tumor.
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Affiliation(s)
- Yu-Sheng Zhang
- a School of Pharmaceutical Sciences, Shandong University , Jinan , China
| | - Feng Wang
- b Beijing Key Laboratory of Environmental Toxicology , Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University , Beijing , China
| | - Shu-Xiang Cui
- b Beijing Key Laboratory of Environmental Toxicology , Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University , Beijing , China
| | - Xian-Jun Qu
- a School of Pharmaceutical Sciences, Shandong University , Jinan , China
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16
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Morales I, Sanchez A, Rodriguez-Sabate C, Rodriguez M. Striatal astrocytes engulf dopaminergic debris in Parkinson's disease: A study in an animal model. PLoS One 2017; 12:e0185989. [PMID: 29028815 PMCID: PMC5640218 DOI: 10.1371/journal.pone.0185989] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 09/23/2017] [Indexed: 11/18/2022] Open
Abstract
The role of astrocytes in Parkinson’s disease is still not well understood. This work studied the astrocytic response to the dopaminergic denervation. Rats were injected in the lateral ventricles with 6-hydroxydopamine (25μg), inducing a dopaminergic denervation of the striatum not accompanied by non-selective tissue damage. The dopaminergic debris were found within spheroids (free-spheroids) which retained some proteins of dopaminergic neurons (e.g., tyrosine hydroxylase, the dopamine transporter protein, and APP) but not others (e.g., α-synuclein). Free-spheroids showed the initial (LC3-autophagosomes) but not the late (Lamp1/Lamp2-lysosomes) components of autophagy (incomplete autophagy), preparing their autophagosomes for an external phagocytosis (accumulation of phosphatidylserine). Free-spheroids were penetrated by astrocyte processes (fenestrated-spheroids) which made them immunoreactive for GFAP and S100β, and which had some elements needed to continue the debris degradation (Lamp1/Lamp2). Finally, proteins normally found in neurons (TH, DAT and α-synuclein) were observed within astrocytes 2–5 days after the dopaminergic degeneration, suggesting that the intracellular contents of degenerated cells had been transferred to astrocytes. Taken together, present data suggest phagocytosis as a physiological role of striatal astrocytes, a role which could be critical for cleaning striatal debris during the initial stages of Parkinson’s disease.
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Affiliation(s)
- Ingrid Morales
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Faculty of Medicine, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
- Center for Networked Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Alberto Sanchez
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Faculty of Medicine, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Clara Rodriguez-Sabate
- Center for Networked Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Manuel Rodriguez
- Laboratory of Neurobiology and Experimental Neurology, Department of Basic Medical Sciences, Faculty of Medicine, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
- Center for Networked Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- * E-mail:
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17
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Weng TY, Hung DT, Su TP, Tsai SYA. Loss of Sigma-1 Receptor Chaperone Promotes Astrocytosis and Enhances the Nrf2 Antioxidant Defense. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:4582135. [PMID: 28883901 PMCID: PMC5573104 DOI: 10.1155/2017/4582135] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/09/2017] [Accepted: 06/28/2017] [Indexed: 12/12/2022]
Abstract
Sigma-1 receptor (Sig-1R) functions as a chaperon that interacts with multiple proteins and lipids and is implicated in neurodegenerative and psychiatric diseases. Here, we used Sig-1R KO mice to examine brain expression profiles of astrocytes and ubiquitinated proteins, which are both hallmarks of central nervous system (CNS) pathologies. Our results showed that Sig-1R KO induces increased glial fibrillary acidic protein (GFAP) expression in primary neuron-glia cultures and in the whole brain of fetus mice with concomitantly increased accumulations of ubiquitinated proteins. Astrogliosis was also observed in the neuron-glia culture. Upon proteasome or autophagy inhibitor treatments, the pronounced ubiquitinated proteins were further increased in Sig-1R KO neurons, indicating that the Sig-1R regulates both protein degradation and quality control systems. We found that Nrf2 (nuclear factor erythroid 2-related factor 2), which functions to overcome the stress condition, was enhanced in the Sig-1R KO systems especially when cells were under stressful conditions. Mutation or deficiency of Sig-1Rs has been observed in neurodegenerative models. Our study identifies the critical roles of Sig-1R in CNS homeostasis and supports the idea that functional complementation pathways are triggered in the Sig-1R KO pathology.
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Affiliation(s)
- Tzu-Yu Weng
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Denise T. Hung
- Cellular Pathobiology Section, Integrative Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, Department of Health and Human Services, National Institutes of Health, Baltimore, MD 21224, USA
| | - Tsung-Ping Su
- Cellular Pathobiology Section, Integrative Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, Department of Health and Human Services, National Institutes of Health, Baltimore, MD 21224, USA
| | - Shang-Yi A. Tsai
- Cellular Pathobiology Section, Integrative Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, Department of Health and Human Services, National Institutes of Health, Baltimore, MD 21224, USA
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18
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Wang L, Liu L, Qin L, Luo Q, Zhang Z. Visualization of reticulophagy in living cells using an endoplasmic reticulum-targeted p62 mutant. SCIENCE CHINA-LIFE SCIENCES 2017; 60:333-344. [PMID: 28424968 DOI: 10.1007/s11427-015-9037-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 01/26/2017] [Indexed: 12/11/2022]
Abstract
Reticulophagy is a type of selective autophagy in which protein aggregate-containing and/or damaged endoplasmic reticulum (ER) fragments are engulfed for lysosomal degradation, which is important for ER homeostasis. Several chemical drugs and mutant proteins that promote protein aggregate formation within the ER lumen can efficiently induce reticulophagy in mammalian cells. However, the exact mechanism and cellular localization of reticulophagy remain unclear. In this report, we took advantage of the self-oligomerization property of p62/SQSTM1, an adaptor for selective autophagy, and developed a novel reticulophagy system based on an ER-targeted p62 mutant to investigate the process of reticulophagy in living cells. LC3 conversion analysis via western blot suggested that p62 mutant aggregate-induced ER stress triggered a cellular autophagic response. Confocal imaging showed that in cells with moderate aggregation conditions, the aggregates of ER-targeted p62 mutants were efficiently sequestered by autophagosomes, which was characterized by colocalization with the autophagosome precursor marker ATG16L1, the omegasome marker DFCP1, and the late autophagosomal marker LC3/GATE-16. Moreover, time-lapse imaging data demonstrated that the LC3- or DFCP1-positive protein aggregates are tightly associated with the reticular structures of the ER, thereby suggesting that reticulophagy occurs at the ER and that omegasomes may be involved in this process.
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Affiliation(s)
- Liang Wang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Lei Liu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Lingsong Qin
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Qingming Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhihong Zhang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
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19
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20
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Park EY, Woo Y, Kim SJ, Kim DH, Lee EK, De U, Kim KS, Lee J, Jung JH, Ha KT, Choi WS, Kim IS, Lee BM, Yoon S, Moon HR, Kim HS. Anticancer Effects of a New SIRT Inhibitor, MHY2256, against Human Breast Cancer MCF-7 Cells via Regulation of MDM2-p53 Binding. Int J Biol Sci 2016; 12:1555-1567. [PMID: 27994519 PMCID: PMC5166496 DOI: 10.7150/ijbs.13833] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 09/30/2016] [Indexed: 12/28/2022] Open
Abstract
The sirtuins (SIRTs), a family of NAD+-dependent class III histone deacetylase, are involved in various biological processes including cell survival, division, senescence, and metabolism via activation of the stress-response pathway. Recently, inhibition of SIRTs has been considered a promising anticancer strategy, but their precise mechanisms of action are not well understood. In particular, the relevance of p53 to SIRT-induced effects has not been fully elucidated. We investigated the anticancer effects of a novel SIRT inhibitor, MHY2256, and its efficacy was compared to that of salermide in MCF-7 (wild-type p53) and SKOV-3 (null-type p53) cells. Cell viability, SIRT1 enzyme activity, cell cycle regulation, apoptosis, and autophagic cell death were measured. We compared sensitivity to cytotoxicity in MCF-7 and SKOV-3 cells. MHY2256 significantly decreased the viability of MCF-7 (IC50, 4.8 μM) and SKOV-3 (IC50, 5.6 μM) cells after a 48 h treatment period. MHY2256 showed potent inhibition (IC50, 0.27 mM) against SIRT1 enzyme activity compared with nicotinamide (IC50, >1 mM). Moreover, expression of SIRT (1, 2, or 3) protein levels was significantly reduced by MHY2256 treatment in both MCF-7 and SKOV-3 cells. Flow cytometry analysis revealed that MHY2256 significantly induced cell cycle arrest in the G1 phase, leading to an effective increase in apoptotic cell death in MCF-7 and SKOV-3 cells. A significant increase in acetylated p53, a target protein of SIRT, was observed in MCF-7 cells after MHY2256 treatment. MHY2256 up-regulated LC3-II and induced autophagic cell death in MCF-7 cells. Furthermore, MHY2256 markedly inhibited tumor growth in a tumor xenograft model of MCF-7 cells. These results suggest that a new SIRT inhibitor, MHY2256, has anticancer activity through p53 acetylation in MCF-7 human breast cancer cells.
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Affiliation(s)
- Eun Young Park
- College of Pharmacy, Pusan National University, San 30, Jangjeon-dong, Geumjeung-gu, Busan, 609-735, Republic of Korea
| | - Youngwoo Woo
- College of Pharmacy, Pusan National University, San 30, Jangjeon-dong, Geumjeung-gu, Busan, 609-735, Republic of Korea
| | - Seong Jin Kim
- College of Pharmacy, Pusan National University, San 30, Jangjeon-dong, Geumjeung-gu, Busan, 609-735, Republic of Korea
| | - Do Hyun Kim
- College of Pharmacy, Pusan National University, San 30, Jangjeon-dong, Geumjeung-gu, Busan, 609-735, Republic of Korea
| | - Eui Kyung Lee
- College of Pharmacy, Pusan National University, San 30, Jangjeon-dong, Geumjeung-gu, Busan, 609-735, Republic of Korea
| | - Umasankar De
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Kyeong Seok Kim
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Jaewon Lee
- College of Pharmacy, Pusan National University, San 30, Jangjeon-dong, Geumjeung-gu, Busan, 609-735, Republic of Korea
| | - Jee H Jung
- College of Pharmacy, Pusan National University, San 30, Jangjeon-dong, Geumjeung-gu, Busan, 609-735, Republic of Korea
| | - Ki-Tae Ha
- Department of Korean Medical Science, School of Korean Medicine and Korean Medicine Research Center for Healthy Aging, Pusan National University, Yangsan, Gyeongsangnam-do, Republic of Korea
| | - Wahn Soo Choi
- Department of Immunology, School of Medicine, Konkuk University, Chungju 380-701, Republic of Korea
| | - In Su Kim
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Byung Mu Lee
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Sungpil Yoon
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Hyung Ryong Moon
- College of Pharmacy, Pusan National University, San 30, Jangjeon-dong, Geumjeung-gu, Busan, 609-735, Republic of Korea
| | - Hyung Sik Kim
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
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Kraft LJ, Dowler J, Manral P, Kenworthy AK. Size, organization, and dynamics of soluble SQSTM1 and LC3-SQSTM1 complexes in living cells. Autophagy 2016; 12:1660-74. [PMID: 27442348 DOI: 10.1080/15548627.2016.1199299] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Selective macroautophagy/autophagy-with the help of molecular receptors-captures cargo for lysosomal degradation. Among the best-studied molecular receptors is SQSTM1/p62, a homo-oligomeric ubiquitin binding protein, which binds to both cargo and MAP1LC3B/LC3, a protein important for autophagosome biogenesis. Although the mechanisms underlying interaction of LC3 and SQSTM1 have been extensively studied, very little is known about the size or organization of soluble complexes formed between SQSTM1 and LC3 prior to phagophore (the autophagosome precursor) binding in live cells at the molecular level. To address this question, in the current study we use a combination of 2 microscopy-based approaches, FRET microscopy and confocal FRAP, to study the nanoscale properties of soluble SQSTM1 complexes and SQSTM1-LC3 complexes in living HeLa cells. We find that, independent of puncta, SQSTM1 oligomerizes to form very slowly diffusing complexes that contain multiple copies of SQSTM1 within FRET proximity of one another. Furthermore, we show that the interactions of soluble pools of LC3 and SQSTM1 can be readily detected by both FRAP and FRET. Finally, we uncover unexpected roles of SQSTM1's PB1 domain, a region of the protein involved in homo-oligomer formation, in complex formation. Taken together, these findings provide new insights into the nature of nanometer-sized protein complexes in the autophagy pathway.
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Affiliation(s)
- Lewis J Kraft
- a Chemical and Physical Biology Program , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Jacob Dowler
- b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Pallavi Manral
- b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Anne K Kenworthy
- a Chemical and Physical Biology Program , Vanderbilt University Medical Center , Nashville , TN , USA.,b Department of Molecular Physiology and Biophysics , Vanderbilt University Medical Center , Nashville , TN , USA.,c Department of Cell and Developmental Biology , Vanderbilt University Medical Center , Nashville , TN , USA
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22
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Chapin HC, Okada M, Merz AJ, Miller DL. Tissue-specific autophagy responses to aging and stress in C. elegans. Aging (Albany NY) 2016; 7:419-34. [PMID: 26142908 PMCID: PMC4505168 DOI: 10.18632/aging.100765] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cellular function relies on a balance between protein synthesis and breakdown. Macromolecular breakdown through autophagy is broadly required for cellular and tissue development, function, and recovery from stress. While Caenorhabditis elegans is frequently used to explore cellular responses to development and stress, the most common assays for autophagy in this system lack tissue-level resolution. Different tissues within an organism have unique functional characteristics and likely vary in their reliance on autophagy under different conditions. To generate a tissue-specific map of autophagy in C. elegans we used a dual fluorescent protein (dFP) tag that releases monomeric fluorescent protein (mFP) upon arrival at the lysosome. Tissue-specific expression of dFP::LGG-1 revealed autophagic flux in all tissues, but mFP accumulation was most dramatic in the intestine. We also observed variable responses to stress: starvation increased autophagic mFP release in all tissues, whereas anoxia primarily increased intestinal autophagic flux. We observed autophagic flux with tagged LGG-1, LGG-2, and two autophagic cargo reporters: a soluble cytoplasmic protein, and mitochondrial TOMM-7. Finally, an increase in mFP in older worms was consistent with an age-dependent shift in proteostasis. These novel measures of autophagic flux in C. elegans reveal heterogeneity in autophagic response across tissues during stress and aging.
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Affiliation(s)
- Hannah C Chapin
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Megan Okada
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Alexey J Merz
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Dana L Miller
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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Park JS, Kang DH, Lee DH, Bae SH. PF-4708671, a specific inhibitor of p70 ribosomal S6 kinase 1, activates Nrf2 by promoting p62-dependent autophagic degradation of Keap1. Biochem Biophys Res Commun 2015; 466:499-504. [PMID: 26381178 DOI: 10.1016/j.bbrc.2015.09.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 09/11/2015] [Indexed: 12/13/2022]
Abstract
p70 ribosomal S6 kinase 1 (S6K1) is an important serine/threonine kinase and downstream target of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway. PF-4708671 is a specific inhibitor of S6K1, and prevents S6K1-mediated phosphorylation of the S6 protein. PF-4708671 treatment often leads to apoptotic cell death. However, the protective mechanism against PF-4708671-induced cell death has not been elucidated. The nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway is essential for protecting cells against oxidative stress. p62, an adaptor protein in the autophagic process, enhances Nrf2 activation through the impairment of Keap1 activity. In this study, we showed that PF-4708671 induces autophagic Keap1 degradation-mediated Nrf2 activation in p62-dependent manner. Furthermore, p62-dependent Nrf2 activation plays a crucial role in protecting cells from PF-4708671-mediated apoptosis.
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Affiliation(s)
- Jeong Su Park
- Severance Biomedical Science Institute, Republic of Korea; Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea
| | - Dong Hoon Kang
- Department of Life Science and Ewha Research Center for Systems Biology, Republic of Korea; The Research Center for Cell Homeostasis, Ewha Womans University, Seoul 127-750, Republic of Korea
| | - Da Hyun Lee
- Severance Biomedical Science Institute, Republic of Korea; Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea
| | - Soo Han Bae
- Severance Biomedical Science Institute, Republic of Korea; Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea.
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Analyzing the Colocalization of MAP1LC3 and Lysosomal Markers in Primary Cells. Cold Spring Harb Protoc 2015; 2015:pdb.prot086272. [PMID: 26330623 DOI: 10.1101/pdb.prot086272] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This technique evaluates the colocalization of the autophagy protein MAP1LC3 (microtubule-associated proteins 1A/1B light chain 3B, here referred to as LC3) with lysosomes (autolysosomes) in primary cells in a high-throughput manner. It uses an imaging fluorescence-activated cell sorting cytometer called the ImageStream to concomitantly detect surface molecules, making possible the identification of cells in mixed cell populations (e.g., in blood or bone marrow). It can be applied to clinical samples and to rare cell populations because only a few cells are needed for detection.
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Luo H, Lu L, Yang F, Wang L, Yang X, Luo Q, Zhang Z. Nasopharyngeal cancer-specific therapy based on fusion peptide-functionalized lipid nanoparticles. ACS NANO 2014; 8:4334-4347. [PMID: 24766601 DOI: 10.1021/nn405989n] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Current treatment of advanced-stage nasopharyngeal carcinoma (NPC) is not satisfactory. Targeted therapies offer hope for extending survival. Here, we developed simple, robust, and NPC-specific therapeutic lipid nanoparticles based on a fusion peptide, α-NTP, made up of an amphipathic α-helical peptide (α-peptide) linked to an NPC-specific therapeutic peptide (NTP). We found that α-NTP not only retained the sub-30 nm nanostructure-controlling ability of the α-peptide but also displayed the enhanced NPC-targeting ability of the NTP, in which the α-peptide accelerated the uptake of the NTP by NPC cells, with a 4.8-fold increase. Following uptake, α-NTP-based lipid nanoparticles (α-NTP-LNs) exerted coordinated cytotoxicity by inducing cell death via apoptosis and autophagy. In vivo and ex vivo optical imaging data showed that systemically administered α-NTP-LNs efficiently accumulated in the NPC xenograft tumor and displayed high contrast between tumor and normal tissues, which was further confirmed by flow cytometry that there had been a 13-fold uptake difference between tumor cells and hepatocytes. More importantly, the therapeutic efficacy of α-NTP-LNs was specific to NPC xenograft formed with 5-8F cells but not to fibrosarcoma xenograft formed with HT1080 cells in vivo. The growth of 5-8F tumors was significantly inhibited by α-NTP-LNs, with more than 85% inhibition relative to control groups (e.g., α-NTP and PBS treatment). In a lung metastasis model of NPC, survival was significantly improved by α-NTP-LN treatment. In a word, these excellent properties of α-NTP-LNs worked in sync and synergistically, maximizing the therapeutic efficacy of α-NTP-LNs against NPC and its metastasis.
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Affiliation(s)
- Haiming Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, and ‡MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
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Kraft LJ, Nguyen TA, Vogel SS, Kenworthy AK. Size, stoichiometry, and organization of soluble LC3-associated complexes. Autophagy 2014; 10:861-77. [PMID: 24646892 PMCID: PMC4768459 DOI: 10.4161/auto.28175] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
MAP1LC3B, an ortholog of yeast Atg8 and a member of the family of proteins formerly also known as ATG8 in mammals (LC3B henceforth in the text), functions in autophagosome formation and autophagy substrate recruitment. LC3 exists in both a soluble (autophagosome-independent) form as well as a lipid modified form that becomes tightly incorporated into autophagosomal membranes. Although LC3 is known to associate with tens of proteins, relatively little is known about soluble LC3 aside from its interactions with the LC3 lipid conjugation machinery. In previous studies we found autophagosome-independent GFP-LC3B diffuses unusually slowly for a protein of its size, suggesting it may constitutively associate with a high molecular weight complex, form homo-oligomers or aggregates, or reversibly bind microtubules or membranes. To distinguish between these possibilities, we characterized the size, stoichiometry, and organization of autophagosome-independent LC3B in living cells and in cytoplasmic extracts using fluorescence recovery after photobleaching (FRAP) and fluorescence polarization fluctuation analysis (FPFA). We found that the diffusion of LC3B was unaffected by either mutational disruption of its lipid modification or microtubule depolymerization. Brightness and homo-FRET analysis indicate LC3B does not homo-oligomerize. However, mutation of specific residues on LC3B required for binding other proteins and mRNA altered the effective hydrodynamic radius of the protein as well as its stoichiometry. We conclude that when not bound to autophagosomes, LC3B associates with a multicomponent complex with an effective size of ~500 kDa in the cytoplasm. These findings provide new insights into the nature of soluble LC3B and illustrate the power of FRAP and FPFA to investigate the emergent properties of protein complexes in the autophagy pathway.
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Affiliation(s)
- Lewis J Kraft
- Chemical and Physical Biology Program; Department of Molecular Physiology and Biophysics; Department of Cell and Developmental Biology; Vanderbilt University Medical Center; Nashville, TN USA
| | - Tuan A Nguyen
- Section on Cellular Biophotonics, Laboratory of Molecular Physiology; National Institute on Alcohol Abuse and Alcoholism; National Institutes of Health; Rockville, MD USA
| | - Steven S Vogel
- Section on Cellular Biophotonics, Laboratory of Molecular Physiology; National Institute on Alcohol Abuse and Alcoholism; National Institutes of Health; Rockville, MD USA
| | - Anne K Kenworthy
- Chemical and Physical Biology Program; Department of Molecular Physiology and Biophysics; Department of Cell and Developmental Biology; Vanderbilt University Medical Center; Nashville, TN USA
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