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Jin J, Huang R, Chang Y, Yi X. Roles and mechanisms of optineurin in bone metabolism. Biomed Pharmacother 2024; 172:116258. [PMID: 38350370 DOI: 10.1016/j.biopha.2024.116258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 01/30/2024] [Accepted: 02/06/2024] [Indexed: 02/15/2024] Open
Abstract
Optineurin (OPTN) is a widely expressed multifunctional articulatory protein that participates in cellular or mitochondrial autophagy, vesicular transport, and endoplasmic reticulum (ER) stress via interactions with various proteins. Skeletal development is a complex biological process that requires the participation of various osteoblasts, such as bone marrow mesenchymal stem cells (BMSCs), and osteogenic, osteoclastic, and chondrogenic cells. OPTN was recently found to be involved in the regulation of osteoblast activity, which affects bone metabolism. OPTN inhibits osteoclastogenesis via signaling pathways, including NF-κB, IFN-β, and NRF2. OPTN can promote the differentiation of BMSCs toward osteogenesis and inhibit lipogenic differentiation by delaying BMSC senescence and autophagy. These effects are closely related to the development of bone metabolism disorders, such as Paget's disease of bone, rheumatoid arthritis, and osteoporosis. Therefore, this review aims to explore the role and mechanism of OPTN in the regulation of bone metabolism and related bone metabolic diseases. Our findings will provide new targets and strategies for the prevention and treatment of bone metabolic diseases.
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Affiliation(s)
- Junjie Jin
- School of Sports and Human Sciences, Shenyang Sport University, No. 36 Jinqiansong East Road, Sujiatun District, Shenyang, Liaoning 110115, China
| | - Ruiqi Huang
- School of Physical Education, Liaoning Normal University, Dalian 116029, China
| | - Yixing Chang
- Jilin University, No. 2699 Qianjin Street, Changchun, Jilin 130012, China
| | - Xuejie Yi
- Exercise and Health Research Center/Department of Kinesiology, Shenyang Sport University, No. 36 Jinqiansong East Road, Sujiatun District, Shenyang , Liaoning 110115, China.
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Pasquale LR, Gong L, Wiggs JL, Pan L, Yang Z, Wu M, Yang Z, Chen DF, Zeng W. Development of Primary Open Angle Glaucoma-Like Features in a Rhesus Macaque Colony From Southern China. Transl Vis Sci Technol 2021; 10:20. [PMID: 34403473 PMCID: PMC8374995 DOI: 10.1167/tvst.10.9.20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Purpose To describe the ocular phenotype of spontaneous glaucoma in a non-human primate colony. Methods In total, 722 Rhesus macaque monkeys aged 10 to 25 years underwent optical coherence tomography (OCT), fundus photography (FP), and intraocular pressure (IOP) measurements. Monkeys with baseline cup-to-disc ratio (CDR) <0.5 were used to establish baseline ocular features. A subset was followed longitudinally for three years and compared to glaucoma suspects on the basis of OCT/FP criteria. Results The average IOP under ketamine sedation and average CDR for the entire colony was 13.0 ± 4.3 mm Hg and 0.38 ± 0.07, respectively. The mean baseline conscious IOP of glaucoma suspects (N = 18) versus controls (N = 108) was 16.2 ± 3.5 mm Hg and 13.9 ± 2.3 mm Hg, respectively (P = 0.001). All glaucoma suspects had unremarkable slit lamp examinations and open angles based on anterior segment OCT. Baseline global circumpapillary retinal nerve fiber layer (RNFL) thickness was 91.5 ± 11.0 µM versus 102.7 ± 8.5 µM in suspects and controls, respectively (P < 0.0001). All sectors on the baseline circumpapillary OCT showed a significant reduction in RNFL thickness versus controls (P ≤ 0.0022) except for the temporal sector (P ≥ 0.07). In three-year longitudinal analysis, neither CDR nor OCT parameters changed in controls (N = 40; P ≥ 0.16), whereas significant increase in CDR (P = 0.018) and nominally significant decreases in two OCT sectors (nasal, P = 0.023 and nasal inferior, P = 0.046) were noted in suspects. Conclusions Members of a nonhuman primate colony exhibit important ophthalmic features of human primary open-angle glaucoma. Translational Relevance Identification of a spontaneous model of glaucoma in nonhuman primates represents an unprecedented opportunity to elucidate the natural history, pathogenesis and effective therapeutic strategies for the disease.
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Affiliation(s)
- Louis R Pasquale
- Eye and Vision Research Institute of New York Eye and Ear at Mount Sinai, Mount Sinai Icahn School of Medicine, New York, NY, USA
| | - Li Gong
- PriMed Non-human Primate Research Center of Sichuan PriMed Shines Bio-tech Co., Ltd., Ya'an, Sichuan Province, China
| | - Janey L Wiggs
- Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Lingzhen Pan
- PriMed Non-human Primate Research Center of Sichuan PriMed Shines Bio-tech Co., Ltd., Ya'an, Sichuan Province, China
| | - Zhenyan Yang
- PriMed Non-human Primate Research Center of Sichuan PriMed Shines Bio-tech Co., Ltd., Ya'an, Sichuan Province, China
| | - Mingling Wu
- PriMed Non-human Primate Research Center of Sichuan PriMed Shines Bio-tech Co., Ltd., Ya'an, Sichuan Province, China
| | - Zunyuan Yang
- PriMed Non-human Primate Research Center of Sichuan PriMed Shines Bio-tech Co., Ltd., Ya'an, Sichuan Province, China
| | - Dong Feng Chen
- Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Wen Zeng
- PriMed Non-human Primate Research Center of Sichuan PriMed Shines Bio-tech Co., Ltd., Ya'an, Sichuan Province, China
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Qiu Y, Wang J, Li H, Yang B, Wang J, He Q, Weng Q. Emerging views of OPTN (optineurin) function in the autophagic process associated with disease. Autophagy 2021; 18:73-85. [PMID: 33783320 DOI: 10.1080/15548627.2021.1908722] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Macroautophagy/autophagy is a highly conserved process in eukaryotic cells. It plays a critical role in cellular homeostasis by delivering cytoplasmic cargos to lysosomes for selective degradation. OPTN (optineurin), a well-recognized autophagy receptor, has received considerable attention due to its multiple roles in the autophagic process. OPTN is associated with many human disorders that are closely related to autophagy, such as rheumatoid arthritis, osteoporosis, and nephropathy. Here, we review the function of OPTN as an autophagy receptor at different stages of autophagy, focusing on cargo recognition, autophagosome formation, autophagosome maturation, and lysosomal quality control. OPTN tends to be protective in most autophagy associated diseases, though the molecular mechanism of OPTN regulation in these diseases is not well understood. A comprehensive review of the function of OPTN in autophagy provides valuable insight into the pathogenesis of human diseases related to OPTN and facilitates the discovery of potential key regulators and novel therapeutic targets for disease intervention in patients with autophagic diseases.Abbreviations: ATG: autophagy-related; APAP: acetaminophen; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CC: coiled-coil; HACE1: HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1; MYO6: myosin VI; IKBKG/NEMO: inhibitor of nuclear factor kappa B kinase regulatory subunit gamma; IKK: IκB kinase; LIR: LC3-interacting region; LZ: leucine zipper; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NFKB/NF-κB: nuclear factor kappa B subunit; OPTN: optineurin; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; RTECs: renal tubular epithelial cells; SQSTM1/p62: sequestosome 1; TBK1: TANK binding kinase 1; TOM1: target of myb1 membrane trafficking protein; UBD: ubiquitin-binding domain; ULK1: unc-51 like autophagy activating kinase 1; WIPI2: WD repeat domain, phosphoinositide interacting 2; ZF: zinc finger.
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Affiliation(s)
- Yueping Qiu
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Jincheng Wang
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Hui Li
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Bo Yang
- Institute of Pharmacology & Toxicology, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Jiajia Wang
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Qiaojun He
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.,Innovation Institute for Artificial Intelligence in Medicine, Zhejiang University, Hangzhou, China
| | - Qinjie Weng
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.,Innovation Institute for Artificial Intelligence in Medicine, Zhejiang University, Hangzhou, China
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Medchalmi S, Tare P, Sayyad Z, Swarup G. A glaucoma- and ALS-associated mutant of OPTN induces neuronal cell death dependent on Tbk1 activity, autophagy and ER stress. FEBS J 2021; 288:4576-4595. [PMID: 33548116 DOI: 10.1111/febs.15752] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 01/04/2021] [Accepted: 02/04/2021] [Indexed: 02/06/2023]
Abstract
Mutations in OPTN are associated with glaucoma, an eye disease, and also with amyotrophic lateral sclerosis (ALS), a motor neuron disease. A 2-bp insertion in OPTN (691_692insAG or 2bpIns-OPTN) is associated with both glaucoma and ALS. This mutation results in frame shift after 127 amino acids, giving rise to a protein with C-terminal aberrant sequence. We have explored the mechanism of induction of cell death by this mutant in a motor neuron cell line, NSC-34, and also in a retinal cell line, 661W. Compared to wild-type OPTN, this mutant induced more cell death in NSC-34 and 661W cells. This mutant localizes predominantly in the nucleus whereas normal OPTN localizes in the cytoplasm. Deletion analysis of 2bpIns-OPTN showed that the aberrant sequence was not essential for cell death induction. This mutant interacts with TANK-binding kinase 1 (Tbk1) but not with OPTN and activates Tbk1. This mutant induced ER stress in NSC-34 cells as seen by induction of C/EBP homologous protein (CHOP) and some other genes. Induction of CHOP, autophagosomal protein LC3-II and cell death by this mutant were abrogated by Tbk1 knockdown and also by 4-phenylbutyric acid, that inhibits ER stress. Induction of CHOP and cell death by 2bpIns-OPTN was autophagy dependent as shown by the effect of Atg5 knockdown. This mutant caused increased formation of LC3-positive aggregates. Treatment of cells with autophagy inducer rapamycin reduced LC3-positive aggregates, CHOP and cell death induced by 2bpIns-OPTN. These results suggest that constitutive activation of Tbk1 by 2bpIns-OPTN leads to impaired autophagy that results in ER stress and cell death.
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Affiliation(s)
- Swetha Medchalmi
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Priyanka Tare
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | - Ghanshyam Swarup
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
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5
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Guo Q, Wang J, Weng Q. The diverse role of optineurin in pathogenesis of disease. Biochem Pharmacol 2020; 180:114157. [PMID: 32687832 DOI: 10.1016/j.bcp.2020.114157] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/11/2020] [Accepted: 07/14/2020] [Indexed: 02/07/2023]
Abstract
Optineurin is a widely expressed protein that possesses multiple functions. Growing evidence suggests that mutation or dysregulation of optineurin can cause several neurodegenerative diseases, including amyotrophic lateral sclerosis, primary open-angle glaucoma, and Huntington's disease, as well as inflammatory digestive disorders such as Crohn's disease. Optineurin engages in vesicular trafficking, receptor regulation, immune reactions, autophagy, and distinct signaling pathways including nuclear factor kappa beta, by which optineurin contributes to cellular death and related diseases, indicating its potential as a therapeutic target. In this review, we discuss the major functions and signaling pathways of optineurin. Furthermore, we illustrate the influence of optineurin mutation or dysregulation to region-specific pathogenesis as well as potential applications of optineurin in therapeutic strategies.
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Affiliation(s)
- Qingyi Guo
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jincheng Wang
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Qinjie Weng
- Center for Drug Safety Evaluation and Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
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The Genetic and Endoplasmic Reticulum-Mediated Molecular Mechanisms of Primary Open-Angle Glaucoma. Int J Mol Sci 2020; 21:ijms21114171. [PMID: 32545285 PMCID: PMC7312987 DOI: 10.3390/ijms21114171] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 12/14/2022] Open
Abstract
Glaucoma is a heterogenous, chronic, progressive group of eye diseases, which results in irreversible loss of vision. There are several types of glaucoma, whereas the primary open-angle glaucoma (POAG) constitutes the most common type of glaucoma, accounting for three-quarters of all glaucoma cases. The pathological mechanisms leading to POAG pathogenesis are multifactorial and still poorly understood, but it is commonly known that significantly elevated intraocular pressure (IOP) plays a crucial role in POAG pathogenesis. Besides, genetic predisposition and aggregation of abrogated proteins within the endoplasmic reticulum (ER) lumen and subsequent activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-dependent unfolded protein response (UPR) signaling pathway may also constitute important factors for POAG pathogenesis at the molecular level. Glaucoma is commonly known as a ‘silent thief of sight’, as it remains asymptomatic until later stages, and thus its diagnosis is frequently delayed. Thereby, detailed knowledge about the glaucoma pathophysiology is necessary to develop both biochemical and genetic tests to improve its early diagnosis as well as develop a novel, ground-breaking treatment strategy, as currently used medical therapies against glaucoma are limited and may evoke numerous adverse side-effects in patients.
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Identification of a splice variant of optineurin which is defective in autophagy and phosphorylation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1526-1538. [DOI: 10.1016/j.bbamcr.2018.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/10/2018] [Accepted: 08/14/2018] [Indexed: 02/06/2023]
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Optineurin: The autophagy connection. Exp Eye Res 2015; 144:73-80. [PMID: 26142952 DOI: 10.1016/j.exer.2015.06.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/03/2015] [Accepted: 06/30/2015] [Indexed: 01/13/2023]
Abstract
Optineurin is a cytosolic protein encoded by the OPTN gene. Mutations of OPTN are associated with normal tension glaucoma and amyotrophic lateral sclerosis. Autophagy is an intracellular degradation system that delivers cytoplasmic components to the lysosomes. It plays a wide variety of physiological and pathophysiological roles. The optineurin protein is a selective autophagy receptor (or adaptor), containing an ubiquitin binding domain with the ability to bind polyubiquitinated cargoes and bring them to autophagosomes via its microtubule-associated protein 1 light chain 3-interacting domain. It is involved in xenophagy, mitophagy, aggrephagy, and tumor suppression. Optineurin can also mediate the removal of protein aggregates through an ubiquitin-independent mechanism. This protein in addition can induce autophagy upon overexpression or mutation. When overexpressed or mutated, the optineurin protein also serves as a substrate for autophagic degradation. In the present review, the multiple connections of optineurin to autophagy are highlighted.
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Optineurin associates with the podocyte Golgi complex to maintain its structure. Cell Tissue Res 2014; 358:567-83. [PMID: 25096716 DOI: 10.1007/s00441-014-1968-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 07/09/2014] [Indexed: 12/22/2022]
Abstract
Optineurin, a cytosolic protein associated with the actin cytoskeleton, microtubules, and the Golgi complex, appears to have an important function in neurons, as mutations in its gene are causative for neurodegenerative diseases such as primary open-angle glaucoma and amyotrophic lateral sclerosis. Here, we report that optineurin is localized in podocytes of the kidney and induced upon injury following treatment with puromycin aminonucleoside. In cultured human podocytes, optineurin localizes to the Golgi complex. Optineurin depletion by RNA interference causes Golgi fragmentation. Moreover, if the Golgi complex is fragmented following microtubule destabilization induced by nocodazole treatment, optineurin dissociates from Golgi vesicles. Furthermore, optineurin colocalizes with vinculin-labeled focal contacts of cultured podocytes and with lysosome-like structures. Optineurin is essential for the survival of cultured podocytes, as optineurin depletion causes cell death. Thus, optineurin appears to play an important role in the maintenance of the podocyte Golgi complex and in the trafficking of vesicles to focal contacts and lysosomes.
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Wang C, Hosono K, Ohtsubo M, Ohishi K, Gao J, Nakanishi N, Hikoya A, Sato M, Hotta Y, Minoshima S. Interaction between optineurin and the bZIP transcription factor NRL. Cell Biol Int 2013; 38:16-25. [PMID: 23956131 DOI: 10.1002/cbin.10174] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 07/22/2013] [Indexed: 11/07/2022]
Abstract
Although the gene encoding optineurin (OPTN) is a causative gene for glaucoma and amyotrophic lateral sclerosis, it is ubiquitously expressed in all body tissues, including the retina. To study the function of OPTN in retinal ganglion cells as well as the whole retina, we previously isolated OPTN-interacting proteins and identified the gene encoding the bZIP transcription factor neural retina leucine zipper (NRL), which is a causative gene for retinitis pigmentosa. Herein, we investigated the binding between OPTN and NRL proteins in HeLaS3 cells. Co-expression of HA-tagged NRL and FLAG-tagged OPTN in HeLaS3 cells followed by immunoprecipitation and Western blotting with anti-tag antibodies demonstrated the binding of these proteins in HeLaS3 cells, which was confirmed by proximity ligation assay. NRL is the first OPTN-binding protein to show eye-specific expression. A series of partial-deletion OPTN plasmids demonstrated that the tail region (423-577 amino acids [aa]) of OPTN was necessary for binding with NRL. Immunostaining showed that Optn (rat homologue of OPTN) was expressed in rat photoreceptors and localised in the cytoplasm of photoreceptor cells. This is a novel demonstration of Optn expression in photoreceptor cells. OPTN was not detected in photoreceptor nuclei under our experimental conditions. Further analyses are necessary to elucidate the function of OPTN and the significance of its possible binding with NRL in photoreceptor cells.
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Affiliation(s)
- Chunxia Wang
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192, Japan; Department of Photomedical Genomics, Basic Medical Photonics Laboratory, Medical Photonics Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192, Japan; Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang, 110005, China
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Gilger BC, Abarca E, Salmon JH. Selection of Appropriate Animal Models in Ocular Research: Ocular Anatomy and Physiology of Common Animal Models. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2013. [DOI: 10.1007/7653_2013_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ying H, Yue BYJT. Cellular and molecular biology of optineurin. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 294:223-58. [PMID: 22364875 DOI: 10.1016/b978-0-12-394305-7.00005-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Optineurin is a gene linked to glaucoma, amyotrophic lateral sclerosis, other neurodegenerative diseases, and Paget's disease of bone. This review describes the characteristics of optineurin and summarizes the cellular and molecular biology investigations conducted so far on optineurin. Data from a number of laboratories indicate that optineurin is a cytosolic protein containing 577 amino acid residues. Interacting with proteins such as myosin VI, Rab8, huntingtin, transferrin receptor, and TANK-binding kinase 1, optineurin is involved in basic cellular functions including protein trafficking, maintenance of the Golgi apparatus, as well as NF-κB pathway, antiviral, and antibacteria signaling. Mutation or alteration of homeostasis of optineurin (such as overexpression or knockdown) results in adverse consequences in the cells, leading to the development of neurodegenerative diseases including glaucoma.
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Affiliation(s)
- Hongyu Ying
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, College of Medicine, Chicago, Illinois, USA
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Okita S, Morigaki R, Koizumi H, Kaji R, Nagahiro S, Goto S. Cell type-specific localization of optineurin in the striatal neurons of mice: implications for neuronal vulnerability in Huntington's disease. Neuroscience 2011; 202:363-70. [PMID: 22155493 DOI: 10.1016/j.neuroscience.2011.11.059] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 11/21/2011] [Accepted: 11/24/2011] [Indexed: 11/26/2022]
Abstract
Striatal neuropathology of Huntington's disease (HD) involves primary and progressive degeneration of the medium-sized projection neurons, with relative sparing of the local circuit interneurons. The mechanism for such a patterned cell loss in the HD striatum continues to remain unclear. Optineurin (OPTN) is one of the proteins interacting with huntingtin and plays a protective role in several neurodegenerative disorders. To determine the cellular localization pattern of OPTN in the mouse striatum, we employed a highly sensitive immunohistochemistry with the tyramide signal amplification system. In this study, we show that OPTN appeared as a cytoplasmic protein within the subsets of the striatal neurons. Of particular interest was that OPTN was abundantly expressed in the interneurons, whereas low levels of OPTN were observed in the medium projection neurons. This cell type-specific distribution of OPTN in the striatum is strikingly complementary to the pattern of neuronal loss typically observed in the striatum of patients with HD. We suggest that OPTN abundance is an important cellular factor in considering the cell type-specific vulnerability of striatal neurons in HD.
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Affiliation(s)
- S Okita
- Parkinson's Disease and Dystonia Research Center, Tokushima University Hospital, University of Tokushima, Tokushima 770-8503, Japan
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Optineurin inclusions occur in a minority of TDP-43 positive ALS and FTLD-TDP cases and are rarely observed in other neurodegenerative disorders. Acta Neuropathol 2011; 121:519-27. [PMID: 21360076 DOI: 10.1007/s00401-011-0813-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 02/02/2011] [Accepted: 02/16/2011] [Indexed: 10/18/2022]
Abstract
Optineurin (OPTN) is a multifunctional protein involved in vesicular trafficking, signal transduction and gene expression. OPTN mutations were described in eight Japanese patients with familial and sporadic amyotrophic lateral sclerosis (FALS, SALS). OPTN-positive inclusions co-localising with TDP-43 were described in SALS and in FALS with SOD-1 mutations, potentially linking two pathologically distinct pathways of motor neuron degeneration. We have explored the abundance of OPTN inclusions using a range of antibodies in postmortem tissues from 138 cases and controls including sporadic and familial ALS, frontotemporal lobar degeneration (FTLD) and a wide range of neurodegenerative proteinopathies. OPTN-positive inclusions were uncommon and detected in only 11/32 (34%) of TDP-43-positive SALS spinal cord and 5/15 (33%) of FTLD-TDP. Western blot of lysates from FTLD-TDP frontal cortex and TDP-43-positive SALS spinal cord revealed decreased levels of OPTN protein compared to controls (p < 0.05), however, this correlated with decreased neuronal numbers in the brain. Large OPTN inclusions were not detected in FALS with SOD-1 and FUS mutation, respectively, or in FTLD-FUS cases. OPTN-positive inclusions were identified in a few Alzheimer's disease (AD) cases but did not co-localise with tau and TDP-43. Occasional striatal neurons contained granular cytoplasmic OPTN immunopositivity in Huntington's disease (HD) but were absent in spinocerebellar ataxia type 3. No OPTN inclusions were detected in FTLD-tau and α-synucleinopathy. We conclude that OPTN inclusions are relatively rare and largely restricted to a minority of TDP-43 positive ALS and FTLD-TDP cases. Our results do not support the proposition that OPTN inclusions play a central role in the pathogenesis of ALS, FTLD or any other neurodegenerative disorder.
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Park B, Ying H, Shen X, Park JS, Qiu Y, Shyam R, Yue BYJT. Impairment of protein trafficking upon overexpression and mutation of optineurin. PLoS One 2010; 5:e11547. [PMID: 20634958 PMCID: PMC2902519 DOI: 10.1371/journal.pone.0011547] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 06/17/2010] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Glaucoma is a major blinding disease characterized by progressive loss of retinal ganglion cells (RGCs) and axons. Optineurin is one of the candidate genes identified so far. A mutation of Glu(50) to Lys (E50K) has been reported to be associated with a more progressive and severe disease. Optineurin, known to interact with Rab8, myosin VI and transferrin receptor (TfR), was speculated to have a role in protein trafficking. Here we determined whether, and how optineurin overexpression and E50K mutation affect the internalization of transferrin (Tf), widely used as a marker for receptor-mediated endocytosis. METHODOLOGY/PRINCIPAL FINDINGS Human retinal pigment epithelial (RPE) and rat RGC5 cells transfected to overexpress wild type optineurin were incubated with Texas Red-Tf to evaluate Tf uptake. Granular structures or dots referred to as foci formed in perinuclear regions after transfection. An impairment of the Tf uptake was in addition observed in transfected cells. Compared to overexpression of the wild type, E50K mutation yielded an increased foci formation and a more pronounced defect in Tf uptake. Co-transfection with TfR, but not Rab8 or myosin VI, construct rescued the optineurin inhibitory effect, suggesting that TfR was the factor involved in the trafficking phenotype. Forced expression of both wild type and E50K optineurin rendered TfR to colocalize with the foci. Surface biotinylation experiments showed that the surface level of TfR was also reduced, leading presumably to an impeded Tf uptake. A non-consequential Leu(157) to Ala (L157A) mutation that displayed much reduced foci formation and TfR binding had normal TfR distribution, normal surface TfR level and normal Tf internalization. CONCLUSIONS/SIGNIFICANCE The present study demonstrates that overexpression of wild type optineurin results in impairment of the Tf uptake in RPE and RGC5 cells. The phenotype is related to the optineurin interaction with TfR. Our results further indicate that E50K induces more dramatic effects than the wild type optineurin, and is thus a gain-of-function mutation. The defective protein trafficking may be one of the underlying bases why glaucoma pathology develops in patients with E50K mutation.
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Affiliation(s)
- BumChan Park
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
| | - Hongyu Ying
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
| | - Xiang Shen
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
| | - Jeong-Seok Park
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
| | - Ye Qiu
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
| | - Rajalekshmy Shyam
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
| | - Beatrice Y. J. T. Yue
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, Illinois, United States of America
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16
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Albagha OME, Visconti MR, Alonso N, Langston AL, Cundy T, Dargie R, Dunlop MG, Fraser WD, Hooper MJ, Isaia G, Nicholson GC, del Pino Montes J, Gonzalez-Sarmiento R, di Stefano M, Tenesa A, Walsh JP, Ralston SH. Genome-wide association study identifies variants at CSF1, OPTN and TNFRSF11A as genetic risk factors for Paget's disease of bone. Nat Genet 2010; 42:520-4. [PMID: 20436471 PMCID: PMC3217192 DOI: 10.1038/ng.562] [Citation(s) in RCA: 204] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Accepted: 03/05/2010] [Indexed: 12/13/2022]
Abstract
Paget's disease of bone (PDB) is a common disorder with a strong genetic component characterized by focal increases in bone turnover, which in some cases is caused by mutations in SQSTM1. To identify additional susceptibility genes, we performed a genome-wide association study in 750 individuals with PDB (cases) without SQSTM1 mutations and 1,002 controls and identified three candidate disease loci, which were then replicated in an independent set of 500 cases and 535 controls. The strongest signal was with rs484959 on 1p13 near the CSF1 gene (P = 5.38 x 10(-24)). Significant associations were also observed with rs1561570 on 10p13 within the OPTN gene (P = 6.09 x 10(-13)) and with rs3018362 on 18q21 near the TNFRSF11A gene (P = 5.27 x 10(-13)). These studies provide new insights into the pathogenesis of PDB and identify OPTN, CSF1 and TNFRSF11A as candidate genes for disease susceptibility.
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Affiliation(s)
- Omar ME Albagha
- Rheumatic Diseases Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Micaela R Visconti
- Rheumatic Diseases Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Nerea Alonso
- Rheumatic Diseases Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Anne L Langston
- Rheumatic Diseases Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
- Edinburgh Clinical Trials Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Tim Cundy
- Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Rosemary Dargie
- University Department of Medicine, Glasgow Royal Infirmary, Glasgow G4 0SF, UK
| | - Malcolm G Dunlop
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - William D Fraser
- Department of Clinical Chemistry, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - Michael J Hooper
- Department of Medicine, The University of Sydney and Central Sydney Area Health Service, Sydney, Australia
| | - Gianluca Isaia
- Medical and Surgical Department, Geriatric Section, University of Torino, Italy
| | - Geoff C Nicholson
- Department of Clinical and Biomedical Sciences, Barwon Health, Geelong Hospital, University of Melbourne, Melbourne, Australia
| | - Javier del Pino Montes
- Unidad de Medicina Molecular, Departamento de Medicina, Hospital Universitario de Salamanca, Salamanca, Spain
| | - Rogelio Gonzalez-Sarmiento
- Unidad de Medicina Molecular, Departamento de Medicina, Hospital Universitario de Salamanca, Salamanca, Spain
| | - Marco di Stefano
- Medical and Surgical Department, Geriatric Section, University of Torino, Italy
| | - Albert Tenesa
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - John P Walsh
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Perth, Australia
| | - Stuart H Ralston
- Rheumatic Diseases Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
- Edinburgh Clinical Trials Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
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17
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Nagabhushana A, Chalasani ML, Jain N, Radha V, Rangaraj N, Balasubramanian D, Swarup G. Regulation of endocytic trafficking of transferrin receptor by optineurin and its impairment by a glaucoma-associated mutant. BMC Cell Biol 2010; 11:4. [PMID: 20085643 PMCID: PMC2826298 DOI: 10.1186/1471-2121-11-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 01/19/2010] [Indexed: 12/16/2022] Open
Abstract
Background Optineurin is a multifunctional protein involved in several functions such as vesicular trafficking from the Golgi to the plasma membrane, NF-κB regulation, signal transduction and gene expression. Mutations in optineurin are associated with glaucoma, a neurodegenerative eye disease that causes blindness. Genetic evidence suggests that the E50K (Glu50Lys) is a dominant disease-causing mutation of optineurin. However, functional alterations caused by mutations in optineurin are not known. Here, we have analyzed the role of optineurin in endocytic recycling and the effect of E50K mutant on this process. Results We show that the knockdown of optineurin impairs trafficking of transferrin receptor to the juxtanuclear region. A point mutation (D474N) in the ubiquitin-binding domain abrogates localization of optineurin to the recycling endosomes and interaction with transferrin receptor. The function of ubiquitin-binding domain of optineurin is also needed for trafficking of transferrin to the juxtanuclear region. A disease causing mutation, E50K, impairs endocytic recycling of transferrin receptor as shown by enlarged recycling endosomes, slower dynamics of E50K vesicles and decreased transferrin uptake by the E50K-expressing cells. This impaired trafficking by the E50K mutant requires the function of its ubiquitin-binding domain. Compared to wild type optineurin, the E50K optineurin shows enhanced interaction and colocalization with transferrin receptor and Rab8. The velocity of Rab8 vesicles is reduced by co-expression of the E50K mutant. These results suggest that the E50K mutant affects Rab8-mediated transferrin receptor trafficking. Conclusions Our results suggest that optineurin regulates endocytic trafficking of transferrin receptor to the juxtanuclear region. The E50K mutant impairs trafficking at the recycling endosomes due to altered interactions with Rab8 and transferrin receptor. These results also have implications for the pathogenesis of glaucoma caused by the E50K mutation because endocytic recycling is vital for maintaining homeostasis.
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18
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Sudhakar C, Nagabhushana A, Jain N, Swarup G. NF-kappaB mediates tumor necrosis factor alpha-induced expression of optineurin, a negative regulator of NF-kappaB. PLoS One 2009; 4:e5114. [PMID: 19340308 PMCID: PMC2660438 DOI: 10.1371/journal.pone.0005114] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 03/05/2009] [Indexed: 11/19/2022] Open
Abstract
Optineurin is a ubiquitously expressed multifunctional cytoplasmic protein encoded by OPTN gene. The expression of optineurin is induced by various cytokines. Here we have investigated the molecular mechanisms which regulate optineurin gene expression and the relationship between optineurin and nuclear factor κB (NF-κB). We cloned and characterized human optineurin promoter. Optineurin promoter was activated upon treatment of HeLa and A549 cells with tumor necrosis factor α (TNFα). Mutation of a putative NF-κB-binding site present in the core promoter resulted in loss of basal as well as TNFα-induced activity. Overexpression of p65 subunit of NF-κB activated this promoter through NF-κB site. Oligonucleotides corresponding to this putative NF-κB-binding site showed binding to NF-κB. TNFα-induced optineurin promoter activity was inhibited by expression of inhibitor of NF-κB (IκBα) super-repressor. Blocking of NF-κB activation resulted in inhibition of TNFα-induced optineurin gene expression. Overexpressed optineurin partly inhibited TNFα-induced NF-κB activation in Hela cells. Downregulation of optineurin by shRNA resulted in an increase in TNFα-induced as well as basal NF-κB activity. These results show that optineurin promoter activity and gene expression are regulated by NF-κB pathway in response to TNFα. In addition these results suggest that there is a negative feedback loop in which TNFα-induced NF-κB activity mediates expression of optineurin, which itself functions as a negative regulator of NF-κB.
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Affiliation(s)
- Cherukuri Sudhakar
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
| | - Ananthamurthy Nagabhushana
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
| | - Nishant Jain
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
| | - Ghanshyam Swarup
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
- * E-mail:
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19
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Skarie JM, Link BA. The primary open-angle glaucoma gene WDR36 functions in ribosomal RNA processing and interacts with the p53 stress-response pathway. Hum Mol Genet 2008; 17:2474-85. [PMID: 18469340 DOI: 10.1093/hmg/ddn147] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Primary open-angle glaucoma (POAG) is a genetically complex neuropathy that affects retinal ganglion cells and is a leading cause of blindness worldwide. WDR36, a gene of unknown function, was recently identified as causative for POAG at locus GLC1G. Subsequent studies found disease-associated variants in control populations, leaving the role of WDR36 in this disease unclear. To address this issue, we determined the function of WDR36. We studied Wdr36 in zebrafish and found it is the functional homolog of yeast Utp21. Utp21 is cell essential and functions in the nucleolar processing of 18S rRNA, which is required for ribosome biogenesis. Evidence for functional homology comes from sequence alignment, ubiquitous expression, sub-cellular localization to the nucleolus and loss-of-function phenotypes that include defects in 18S rRNA processing and abnormal nucleolar morphology. Additionally, we show that loss of Wdr36 function leads to an activation of the p53 stress-response pathway, suggesting that co-inheritance of defects in p53 pathway genes may influence the impact of WDR36 variants on POAG. Although these results overall do not provide evidence for or against a role of WDR36 in POAG, they do provide important baseline information for future studies.
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Affiliation(s)
- Jonathan M Skarie
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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21
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Park BC, Shen X, Samaraweera M, Yue BYJT. Studies of optineurin, a glaucoma gene: Golgi fragmentation and cell death from overexpression of wild-type and mutant optineurin in two ocular cell types. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 169:1976-89. [PMID: 17148662 PMCID: PMC1762487 DOI: 10.2353/ajpath.2006.060400] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Optineurin (OPTN) has recently been linked to glaucoma, a major cause of blindness worldwide. Mutations in OPTN such as Glu50-->Lys (E50K) have been reported in patients, particularly those with normal pressure glaucoma. Here, we show that the endogenous OPTN was not secreted in two ocular cell types, human trabecular meshwork and retinal pigment epithelial cells. It localized instead in the cytoplasm in a diffuse pattern without a distinct association with the Golgi apparatus. When overexpressed, however, wild-type OPTN-green fluorescent protein (GFP) formed foci especially around the Golgi, colocalizing partially with the common endocytic pathway marker transferrin receptor in both cell types. Fragmentation of the Golgi was also observed. On nocodazole treatment, the OPTN foci were dispersed into the cytoplasm. Overexpression of mutant OPTNE50K-GFP resulted in a greater number (P<0.0055) and size of the foci, compared with the wild type, and the Golgi alteration was potentiated. Cell loss observed in OPTN-expressing cultures was also more pronounced in OPTNE50K-GFP compared with that of wild-type OPTN-GFP counterparts (P<0.01). This study highlights a possible role of OPTN in vesicle trafficking and Golgi integrity. It also provides in-sights into the possible mechanisms why E50K would exhibit a propensity toward the development of glaucoma.
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Affiliation(s)
- Bum-Chan Park
- Department of Ophthalmology and Visual Sciences, College of Medicine, University of Illinois, 1855 W. Taylor Street, Chicago, IL 60612, USA
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