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Zhang N, Nao J, Zhang S, Dong X. Novel insights into the activating transcription factor 4 in Alzheimer's disease and associated aging-related diseases: Mechanisms and therapeutic implications. Front Neuroendocrinol 2024:101144. [PMID: 38797197 DOI: 10.1016/j.yfrne.2024.101144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 05/16/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Ageing is inherent to all human beings, most mechanistic explanations of ageing results from the combined effects of various physiological and pathological processes. Additionally, aging pivotally contributes to several chronic diseases. Activating transcription factor 4 (ATF4), a member of the ATF/cAMP response element-binding protein family, has recently emerged as a pivotal player owing to its indispensable role in the pathophysiological processes of Alzheimer's disease and aging-related diseases. Moreover, ATF4 is integral to numerous biological processes. Therefore, this article aims to comprehensively review relevant research on the role of ATF4 in the onset and progression of aging-related diseases, elucidating its potential mechanisms and therapeutic approaches. Our objective is to furnish scientific evidence for the early identification of risk factors in aging-related diseases and pave the way for new research directions for their treatment. By elucidating the signaling pathway network of ATF4 in aging-related diseases, we aspire to gain a profound understanding of the molecular and cellular mechanisms, offering novel strategies for addressing aging and developing related therapeutics.
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Affiliation(s)
- Nan Zhang
- Department of Neurology, the Seventh Clinical College of China Medical University, No. 24 Central Street, Xinfu District, Fushun 113000, Liaoning, China.
| | - Jianfei Nao
- Department of Neurology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 110000, Liaoning, China.
| | - Shun Zhang
- Department of Neurology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 110000, Liaoning, China.
| | - Xiaoyu Dong
- Department of Neurology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 110000, Liaoning, China.
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2
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Yan X, Wu S, Liu Q, Cheng Y, Teng Y, Ren T, Zhang J, Wang N. Serine to proline mutation at position 341 of MYOC impairs trabecular meshwork function by causing autophagy deregulation. Cell Death Discov 2024; 10:21. [PMID: 38212635 PMCID: PMC10784477 DOI: 10.1038/s41420-024-01801-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 12/24/2023] [Accepted: 01/04/2024] [Indexed: 01/13/2024] Open
Abstract
Glaucoma is a highly heritable disease, and myocilin was the first identified causal and most common pathogenic gene in glaucoma. Serine-to-proline mutation at position 341 of myocilin (MYOCS341P) is associated with severe glaucoma phenotypes in a five-generation primary open-angle glaucoma family. However, the underlying mechanisms are underexplored. Herein, we established the MYOCS341P transgenic mouse model and characterized the glaucoma phenotypes. Further, we systematically explored the functional differences between wild-type and MYOCS341P through immunoprecipitation, mass spectrometry, and RNA-seq analyses. We found that MYOCS341P transgenic mice exhibit glaucoma phenotypes, characterized by reduced aqueous humor outflow, elevated intraocular pressure, decreased trabecular meshwork (TM) cell number, narrowed Schlemm's canal, retinal ganglion cell loss, and visual impairment. Mechanistically, the secretion of dysfunctional MYOCS341P accumulated in the endoplasmic reticulum (ER), inducing ER stress and dysregulation of autophagy, thereby promoting TM cell death. We describe an effective transgenic model for mechanistic studies and the screening of therapeutic targets. Our data generated from high-throughput analyses help elucidate the mechanism underlying mutant MYOC-related glaucoma.
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Affiliation(s)
- Xuejing Yan
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
- Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Shen Wu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
- Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Qian Liu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
- Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Ying Cheng
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
| | - Yufei Teng
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
| | - Tianmin Ren
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
| | - Jingxue Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China.
- Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, 100069, China.
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China.
- Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, 100069, China.
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3
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Sharif NA. Electrical, Electromagnetic, Ultrasound Wave Therapies, and Electronic Implants for Neuronal Rejuvenation, Neuroprotection, Axonal Regeneration, and IOP Reduction. J Ocul Pharmacol Ther 2023; 39:477-498. [PMID: 36126293 DOI: 10.1089/jop.2022.0046] [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] [Indexed: 11/13/2022] Open
Abstract
The peripheral nervous system (PNS) of mammals and nervous systems of lower organisms possess significant regenerative potential. In contrast, although neural plasticity can provide some compensation, the central nervous system (CNS) neurons and nerves of adult mammals generally fail to regenerate after an injury or damage. However, use of diverse electrical, electromagnetic and sonographic energy waves are illuminating novel ways to stimulate neuronal differentiation, proliferation, neurite growth, and axonal elongation/regeneration leading to various levels of functional recovery in animals and humans afflicted with disorders of the CNS, PNS, retina, and optic nerve. Tools such as acupuncture, electroacupuncture, electroshock therapy, electrical stimulation, transcranial magnetic stimulation, red light therapy, and low-intensity pulsed ultrasound therapy are demonstrating efficacy in treating many different maladies. These include wound healing, partial recovery from motor dysfunctions, recovery from ischemic/reperfusion insults and CNS and ocular remyelination, retinal ganglion cell (RGC) rejuvenation, and RGC axonal regeneration. Neural rejuvenation and axonal growth/regeneration processes involve activation or intensifying of the intrinsic bioelectric waves (action potentials) that exist in every neuronal circuit of the body. In addition, reparative factors released at the nerve terminals and via neuronal dendrites (transmitter substances), extracellular vesicles containing microRNAs and neurotrophins, and intercellular communication occurring via nanotubes aid in reestablishing lost or damaged connections between the traumatized tissues and the PNS and CNS. Many other beneficial effects of the aforementioned treatment paradigms are mediated via gene expression alterations such as downregulation of inflammatory and death-signal genes and upregulation of neuroprotective and cytoprotective genes. These varied techniques and technologies will be described and discussed covering cell-based and animal model-based studies. Data from clinical applications and linkage to human ocular diseases will also be discussed where relevant translational research has been reported.
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Affiliation(s)
- Najam A Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, California, USA
- Singapore Eye Research Institute (SERI), Singapore
- SingHealth Duke-NUS Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-National University of Singapore Medical School, Singapore
- Department of Surgery and Cancer, Imperial College of Science and Technology, London, United Kingdom
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, Texas, USA
- Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, Texas, USA
- Department of Pharmacy Sciences, Creighton University, Omaha, Nebraska, USA
- Insitute of Ophthalmology, University College London (UCL), London, United Kingdom
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Askari S, Azizi F, Javadpour P, Karimi N, Ghasemi R. Endoplasmic reticulum stress as an underlying factor in leading causes of blindness and potential therapeutic effects of 4-phenylbutyric acid: from bench to bedside. EXPERT REVIEW OF OPHTHALMOLOGY 2022. [DOI: 10.1080/17469899.2022.2145945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Sahar Askari
- Neuroscience Research center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Azizi
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Pegah Javadpour
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nasser Karimi
- Eye and Skull Base Research Centers, The Five Senses Institute, Iran University of Medical Sciences, Tehran, Iran5Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasoul Ghasemi
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Transgenic Overexpression of Myocilin Leads to Variable Ocular Anterior Segment and Retinal Alterations Associated with Extracellular Matrix Abnormalities in Adult Zebrafish. Int J Mol Sci 2022; 23:ijms23179989. [PMID: 36077382 PMCID: PMC9456529 DOI: 10.3390/ijms23179989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/18/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
Myocilin is an enigmatic glaucoma-associated glycoprotein whose biological role remains incompletely understood. To gain novel insight into its normal function, we used transposon-mediated transgenesis to generate the first zebrafish line stably overexpressing myocilin [Tg(actb1:myoc-2A-mCherry)]. qPCR showed an approximately four-fold increased myocilin expression in transgenic zebrafish embryos (144 hpf). Adult (13 months old) transgenic animals displayed variable and age-dependent ocular anterior segment alterations. Almost 60% of two-year-old male, but not female, transgenic zebrafish developed enlarged eyes with severe asymmetrical and variable abnormalities in the anterior segment, characterized by corneal limbus hypertrophy, and thickening of the cornea, iris, annular ligament and lens capsule. The most severe phenotype presented small or absent ocular anterior chamber and pupils, due to iris overgrowth along with dysplastic retinal growth and optic nerve hypertrophy. Immunohistochemistry revealed increased presence of myocilin in most altered ocular tissues of adult transgenic animals, as well as signs of retinal gliosis and expanded ganglion cells and nerve fibers. The preliminary results indicate that these cells contributed to retinal dysplasia. Visual impairment was demonstrated in all old male transgenic zebrafish. Transcriptomic analysis of the abnormal transgenic eyes identified disrupted expression of genes involved in lens, muscular and extracellular matrix activities, among other processes. In summary, the developed transgenic zebrafish provides a new tool to investigate this puzzling protein and provides evidence for the role of zebrafish myocilin in ocular anterior segment and retinal biology, through the influence of extracellular matrix organization and cellular proliferation.
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Gao L, Gao D, Zhang J, Li C, Wu M, Xiao Y, Yang L, Ma T, Wang X, Zhang M, Yang D, Pan T, Zhang H, Wang A, Jin Y, Chen H. Age-related endoplasmic reticulum stress represses testosterone synthesis via attenuation of the circadian clock in Leydig cells. Theriogenology 2022; 189:137-149. [PMID: 35753227 DOI: 10.1016/j.theriogenology.2022.06.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 06/10/2022] [Accepted: 06/10/2022] [Indexed: 11/18/2022]
Abstract
Senile animals exhibit a high risk of elevated endoplasmic reticulum (ER) stress, attenuated circadian clock, and impaired steroidogenesis in testes. However, how these three processes are intertwined in mouse Leydig cells remains unclear. In this study, a mouse model of aging and hydrogen peroxide (H2O2)-induced senescent TM3 Leydig cells were used to dissect the connections among ER stress, circadian oscillators, and steroidogenesis in Leydig cells. Additionally, thapsigargin (Tg, 60 nM)/tunicamycin (Tm, 60 ng/mL)-induced ER stress were established to investigate the underlying mechanisms by which ER stress regulated testosterone synthesis via circadian clock-related signaling pathways in TM3 cells and primary Leydig cells. Elevated ER stress, attenuated circadian clock, and diminished steroidogenesis were detected in the testes of aged mice (24-month-old) and H2O2-induced (200 μM) senescent TM3 cells in comparison with their control groups. Tg/Tm-induced ER stress reduced the transcription of the circadian clock and steroidogenic genes in TM3 cells and LH-treated (100 ng/mL) primary Leydig cells. Furthermore, 4-phenylbutyric acid (4-PBA, 1 μM), an inhibitor of ER stress, alleviated the inhibitory effect of Tg-mediated ER stress on Per2:Luc oscillations in primary Leydig cells isolated from mPer2Luc knock-in mice, and attenuated the repressive effect of H2O2-induced or Tg-mediated ER stress on the transcription of circadian clock and steroidogenic genes expression and testosterone synthesis in TM3 cells. Collectively, these data indicate that age-related ER stress represses testosterone synthesis via attenuation of the circadian clock in Leydig cells.
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Affiliation(s)
- Lei Gao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; College of Agriculture and Animal Husbandry, Qing Hai University, Xining, 810006, Qinghai, China
| | - Dengke Gao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Jing Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Cuimei Li
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Meina Wu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Yaoyao Xiao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Luda Yang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Tiantian Ma
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Xiaoyu Wang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Manhui Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Dan Yang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Tao Pan
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Haisen Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Aihua Wang
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Yaping Jin
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
| | - Huatao Chen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China; Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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Yan X, Wu S, Liu Q, Cheng Y, Zhang J, Wang N. Myocilin Gene Mutation Induced Autophagy Activation Causes Dysfunction of Trabecular Meshwork Cells. Front Cell Dev Biol 2022; 10:900777. [PMID: 35615698 PMCID: PMC9124892 DOI: 10.3389/fcell.2022.900777] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/08/2022] [Indexed: 12/12/2022] Open
Abstract
Trabecular meshwork dysfunction is the main cause of primary open angle glaucoma (POAG) associated with elevated intraocular pressure (IOP). Mutant myocilin causes glaucoma mainly via elevating IOP. Previously we have found that accumulated Asn 450 Tyr (N450Y) mutant myocilin impairs human trabecular meshwork (TM) cells by inducing chronic endoplasmic reticulum (ER) stress response in vitro. However, it is unclear how ER stress leads to TM damage and whether N450Y myocilin mutation is associated with POAG in vivo. Here we found that N450Y mutant myocilin induces autophagy, which worsens cell viability, whereas inhibition of autophagy increases viability and decreases cell death in human TM cells. Furthermore, we construct a transgenic mouse model of N450Y myocilin mutation (Tg-MYOCN450Y) and Tg-MYOCN450Y mice exhibiting glaucoma phenotypes: IOP elevation, retinal ganglion cell loss and visual impairment. Consistent with our published in vitro studies, mutant myocilin fails to secrete into aqueous humor, causes ER stress and actives autophagy in Tg-MYOCN450Y mice, and aqueous humor dynamics are altered in Tg-MYOCN450Y mice. In summary, our studies demonstrate that activation of autophagy is correlated with pathogenesis of POAG.
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Affiliation(s)
- Xuejing Yan
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Shen Wu
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Qian Liu
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Ying Cheng
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
| | - Jingxue Zhang
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- *Correspondence: Ningli Wang, ; Jingxue Zhang,
| | - Ningli Wang
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- *Correspondence: Ningli Wang, ; Jingxue Zhang,
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Huang Y, Yuan M, Duan F, Yang Y, Lou B, Lin X. Inhibition of endoplasmic reticulum stress by 4-phenylbutyrate alleviates retinal inflammation and the apoptosis of retinal ganglion cells after ocular alkali burn in mice. Inflamm Res 2022; 71:577-590. [PMID: 35415762 DOI: 10.1007/s00011-022-01565-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 02/28/2022] [Accepted: 03/19/2022] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE Retinal ganglion cell (RGC) apoptosis is one of the most severe complications that causes permanent visual impairment following ocular alkali burn (OAB). Currently, very few treatment options exist for this condition. This study was conducted to determine the effect of 4-phenylbutyric acid (4-PBA) on endoplasmic reticulum (ER) stress after OAB using a well-established OAB mouse model. METHODS Ocular alkali burn was induced in C57BL/6 mouse corneas using 1 M NaOH. 4-PBA (10 mg/kg; 250 μL per injection) or saline (250 μL per injection) was injected intraperitoneally once per day for 3 days before the establishment of the OAB model. The apoptosis of retinal ganglion cells (RGCs) was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and the histological damage was examined by hematoxylin and eosin and immunofluorescence assay on retinal flat mounts. The key inflammatory response and the expression of ER stress-related markers in the retinal tissues were assessed by real-time PCR, western blotting and histologic analyses. RESULTS 4-PBA significantly alleviated the apoptosis of RGCs and prevented the structural damage of the retina, as determined by the evaluation of RGC density and retinal thickness. Inhibition of ER stress by 4-PBA decreased the expression of vital proinflammatory cytokines, tumor necrosis factor alpha, and interleukin-1 beta; and suppressed the activation of retinal microglial cells and nuclear factor-kappa B (NF-κB). 4-PBA reduced the expression of the ER stress molecules, glucose-regulated protein 78, activated transcription factor 6, inositol-requiring enzyme-1 (IRE1), X-box-binding protein 1 splicing, and CCAAT/enhancer-binding protein homologous protein, in the retinal tissues and RGCs of OAB mice. CONCLUSIONS The present study demonstrated that the inhibition of ER stress by 4-PBA alleviates the inflammatory response via the IRE1/NF-κB signaling pathway and protects the retina and RGCs from injury in an OAB mouse model. Such findings further suggest that 4-PBA might have potential therapeutic implications for OAB treatment.
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Affiliation(s)
- Yanqiao Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Miner Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Fang Duan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Yao Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Bingsheng Lou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xiaofeng Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China.
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Wilson MR, Satapathy S, Jeong S, Fini ME. Clusterin, other extracellular chaperones, and eye disease. Prog Retin Eye Res 2021; 89:101032. [PMID: 34896599 DOI: 10.1016/j.preteyeres.2021.101032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 12/15/2022]
Abstract
Proteostasis refers to all the processes that maintain the correct expression level, location, folding and turnover of proteins, essential to organismal survival. Both inside cells and in body fluids, molecular chaperones play key roles in maintaining proteostasis. In this article, we focus on clusterin, the first-recognized extracellular mammalian chaperone, and its role in diseases of the eye. Clusterin binds to and inhibits the aggregation of proteins that are misfolded due to mutations or stresses, clears these aggregating proteins from extracellular spaces, and facilitates their degradation. Clusterin exhibits three main homeostatic activities: proteostasis, cytoprotection, and anti-inflammation. The so-called "protein misfolding diseases" are caused by aggregation of misfolded proteins that accumulate pathologically as deposits in tissues; we discuss several such diseases that occur in the eye. Clusterin is typically found in these deposits, which is interpreted to mean that its capacity as a molecular chaperone to maintain proteostasis is overwhelmed in the disease state. Nevertheless, the role of clusterin in diseases involving such deposits needs to be better defined before therapeutic approaches can be entertained. A more straightforward case can be made for therapeutic use of clusterin based on its proteostatic role as a proteinase inhibitor, as well as its cytoprotective and anti-inflammatory properties. It is likely that clusterin works together in this way with other extracellular chaperones to protect the eye from disease, and we discuss several examples. We end this article by predicting future steps that may lead to development of clusterin as a biological drug.
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Affiliation(s)
- Mark R Wilson
- Molecular Horizons and the School of Chemistry and Molecular Bioscience, University of Wollongong; Illawarra Health and Medical Research Institute, Northfields Avenue, Wollongong, New South Wales, 2522, Australia.
| | - Sandeep Satapathy
- Molecular Horizons and the School of Chemistry and Molecular Bioscience, University of Wollongong; Illawarra Health and Medical Research Institute, Northfields Avenue, Wollongong, New South Wales, 2522, Australia.
| | - Shinwu Jeong
- USC Roski Eye Institute and Department of Ophthalmology, Keck School of Medicine of USC, University of Southern California, 1333 San Pablo Street., Los Angeles, CA, 90033, USA.
| | - M Elizabeth Fini
- New England Eye Center, Tufts Medical Center and Department of Ophthalmology, Tufts University School of Medicine; Program in Pharmacology & Drug Development, Graduate School of Biomedical Sciences, Tufts University, 800 Washington St, Boston, MA, 02111, USA.
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10
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Sui S, Yu H, Wang X, Wang W, Yang X, Pan X, Zhou Q, Xin C, Du R, Wu S, Zhang J, Cao Q, Wang N, Kuehn MH, Zhu W. iPSC-Derived Trabecular Meshwork Cells Stimulate Endogenous TM Cell Division Through Gap Junction in a Mouse Model of Glaucoma. Invest Ophthalmol Vis Sci 2021; 62:28. [PMID: 34427623 PMCID: PMC8399400 DOI: 10.1167/iovs.62.10.28] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Purpose Decreased trabecular meshwork (TM) cellularity has been implicated as a major reason for TM dysfunction and aqueous humor (AH) outflow abnormalities in primary open angle glaucoma. We previously found that transplantation of induced pluripotent stem cell (iPSC)-derived TM cells can restore TM function and stimulate endogenous TM cell division. The goal of the present study is to investigate whether signaling via gap junctions is involved in this process. Methods Differentiated iPSCs were characterized morphologically, transcriptionally, and immunohistochemically. After purification, iPSC-TM were co-cultured with mouse TM (MTM) cells to mimic the transplantation procedure. Through the pharmacological antagonists and short hairpin RNA (shRNA) technique, the gap junction function in iPSC-based therapy was determined. Results In the co-culture system, iPSC-TM increase MTM cell division as well as transfer of Ca2+ to MTM. This effect was blocked by treatment with the gap junction inhibitors carbenoxolone (CBX) or flufenamic acid (FFA). The shRNA mediated knock down of connexin 43 (Cx43) expression in iPSC-TM also results in decreased Ca2+ transfer and lower MTM proliferation rates. In vivo, Cx43 downregulation in transplanted iPSC-TM weakened their regenerative role in an Ad5.myocilinY437H mouse model of glaucoma. Mice receiving these cells exhibited lower TM cellularity and higher intraocular pressure (IOP) than those receiving unmodified iPSC-TM. Conclusions Our findings reveal a crucial role of gap junction, especially Cx43, in iPSC-based TM regeneration, and provides insights to enhance the regenerative effect of iPSCs in glaucoma therapy.
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Affiliation(s)
- Shangru Sui
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, China
| | - Hongxia Yu
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, China.,Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiangji Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, China
| | - Wenyan Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, China
| | - Xuejiao Yang
- Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaojing Pan
- Qingdao Eye Hospital, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China
| | - Qingjun Zhou
- Qingdao Eye Hospital, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China
| | - Chen Xin
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Beijing, China
| | - Rong Du
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Beijing, China
| | - Shen Wu
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Beijing, China
| | - Jingxue Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Beijing, China
| | - Qilong Cao
- Qingdao Haier Biotech Co. Ltd., Qingdao, China
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Beijing, China
| | - Markus H Kuehn
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA.,Center for the Prevention and Treatment of Visual Loss, Iowa City Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Wei Zhu
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beijing University & Capital Medical University, Beijing, China
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11
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Khatibi S, Sahebkar A, Aghaee-Bakhtiari SH. CRISPR Genome Editing Technology and its Application in Genetic Diseases: A Review. Curr Pharm Biotechnol 2021; 22:468-479. [PMID: 32564746 DOI: 10.2174/1389201021666200621161610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/29/2020] [Accepted: 05/18/2020] [Indexed: 11/22/2022]
Abstract
Gene therapy has been a long lasting goal for scientists, and there are many optimal methods and tools to correct disease-causing mutations in humans. Recently, the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology has been progressively adopted for the assessment a treatment of human diseases, including thalassemia, Parkinson's disease, cystic fibrosis, glaucoma, Huntington's disease, and Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS). CRISPR sequences belong to the bacterial immune system, which includes the nuclease Cas enzyme and an RNA sequence. The RNA sequence is unique and pathogen-specific, and identifies and binds to the DNA of invasive viruses, allowing the nuclease Cas enzyme to cut the identified DNA and destroy the invasive viruses. This feature provides the possibility to edit mutations in the DNA sequence of live cells by replacing a specific targeted RNA sequence with the RNA sequence in the CRISPR system. Previous studies have reported the improvement steps in confrontation with human diseases caused by single-nucleotide mutations using this system. In this review, we first introduce CRISPR and its functions and then elaborate on the use of CRISPR in the treatment of human diseases.
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Affiliation(s)
- Sepideh Khatibi
- Department of Medical Biotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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12
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Lieberman RL, Ma MT. Molecular Insights into Myocilin and Its Glaucoma-Causing Misfolded Olfactomedin Domain Variants. Acc Chem Res 2021; 54:2205-2215. [PMID: 33847483 DOI: 10.1021/acs.accounts.1c00060] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Numerous human disorders arise due to the inability of a particular protein to adopt its correct three-dimensional structure in the context of the cell, leading to aggregation. A new addition to the list of such protein conformational disorders is the inherited subtype of glaucoma. Different and rare coding mutations in myocilin, found in families throughout the world, are causal for early onset ocular hypertension, a key glaucoma risk factor. Myocilin is expressed at high levels in the trabecular meshwork (TM) extracellular matrix. The TM is the anatomical region of the eye that regulates intraocular pressure, and its dysfunction is associated with most forms of glaucoma. Disease variants, distributed across the 30 kDa olfactomedin domain (mOLF), cause myocilin to be sequestered intracellularly instead of being secreted to the TM extracellular matrix. The working hypothesis is that the intracellular aggregates cause a toxic gain of function: TM cell death is thought to lead to TM matrix dysfunction, hastening elevated intraocular pressure and subsequent vision loss.Our lab has provided molecular underpinnings for myocilin structure and misfolding, placing myocilin-associated glaucoma within the context of amyloid diseases like Alzheimer and diabetes. We have dissected complexities of the modular wild-type (WT) myocilin structure and associated misfolded states. Our data support the model that full-length WT myocilin adopts a Y-shaped dimer-of-dimers conferred by two different coiled-coil regions, generating new hypotheses regarding its mysterious function. The mOLF β-propellers are paired at each tip of the Y. Disease-associated variants aggregate because mOLFs are less stable, leading to facile aggregation under physiological conditions (37 °C, pH 7.2). Mutant myocilin aggregates exhibit numerous characteristics of amyloid in vitro and in cells, and aggregation proceeds from a partially folded state accessed preferentially by disease variants at physiological conditions. Interestingly, destabilization is not a universal consequence of mutation. We identified counterintuitive, stabilizing point variants that adopt a non-native structure and do not aggregate; however, these variants have not been identified in glaucoma patients. An ongoing effort is predicting the consequence of any given mutation. This effort is relevant to interpreting data from large-scale sequencing projects where clinical and family history data are not available. Finally, our work suggests avenues to develop disease-modifying precision medicines for myocilin-associated glaucoma.
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Affiliation(s)
- Raquel L. Lieberman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr. NW, Atlanta, Georgia 30332-0400, United States
| | - Minh Thu Ma
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr. NW, Atlanta, Georgia 30332-0400, United States
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13
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Patel PD, Chen YL, Kasetti RB, Maddineni P, Mayhew W, Millar JC, Ellis DZ, Sonkusare SK, Zode GS. Impaired TRPV4-eNOS signaling in trabecular meshwork elevates intraocular pressure in glaucoma. Proc Natl Acad Sci U S A 2021; 118:e2022461118. [PMID: 33853948 PMCID: PMC8072326 DOI: 10.1073/pnas.2022461118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Primary Open Angle Glaucoma (POAG) is the most common form of glaucoma that leads to irreversible vision loss. Dysfunction of trabecular meshwork (TM) tissue, a major regulator of aqueous humor (AH) outflow resistance, is associated with intraocular pressure (IOP) elevation in POAG. However, the underlying pathological mechanisms of TM dysfunction in POAG remain elusive. In this regard, transient receptor potential vanilloid 4 (TRPV4) cation channels are known to be important Ca2+ entry pathways in multiple cell types. Here, we provide direct evidence supporting Ca2+ entry through TRPV4 channels in human TM cells and show that TRPV4 channels in TM cells can be activated by increased fluid flow/shear stress. TM-specific TRPV4 channel knockout in mice elevated IOP, supporting a crucial role for TRPV4 channels in IOP regulation. Pharmacological activation of TRPV4 channels in mouse eyes also improved AH outflow facility and lowered IOP. Importantly, TRPV4 channels activated endothelial nitric oxide synthase (eNOS) in TM cells, and loss of eNOS abrogated TRPV4-induced lowering of IOP. Remarkably, TRPV4-eNOS signaling was significantly more pronounced in TM cells compared to Schlemm's canal cells. Furthermore, glaucomatous human TM cells show impaired activity of TRPV4 channels and disrupted TRPV4-eNOS signaling. Flow/shear stress activation of TRPV4 channels and subsequent NO release were also impaired in glaucomatous primary human TM cells. Together, our studies demonstrate a central role for TRPV4-eNOS signaling in IOP regulation. Our results also provide evidence that impaired TRPV4 channel activity in TM cells contributes to TM dysfunction and elevated IOP in glaucoma.
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Affiliation(s)
- Pinkal D Patel
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - Yen-Lin Chen
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908
| | - Ramesh B Kasetti
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - Prabhavathi Maddineni
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - William Mayhew
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - J Cameron Millar
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - Dorette Z Ellis
- Department of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - Swapnil K Sonkusare
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908;
- Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Gulab S Zode
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107;
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14
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Kasetti RB, Maddineni P, Kiehlbauch C, Patil S, Searby CC, Levine B, Sheffield VC, Zode GS. Autophagy stimulation reduces ocular hypertension in a murine glaucoma model via autophagic degradation of mutant myocilin. JCI Insight 2021; 6:143359. [PMID: 33539326 PMCID: PMC8021112 DOI: 10.1172/jci.insight.143359] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Elevation of intraocular pressure (IOP) due to trabecular meshwork (TM) damage is associated with primary open-angle glaucoma (POAG). Myocilin mutations resulting in elevated IOP are the most common genetic causes of POAG. We have previously shown that mutant myocilin accumulates in the ER and induces chronic ER stress, leading to TM damage and IOP elevation. However, it is not understood how chronic ER stress leads to TM dysfunction and loss. Here, we report that mutant myocilin activated autophagy but was functionally impaired in cultured human TM cells and in a mouse model of myocilin-associated POAG (Tg-MYOCY437H). Genetic and pharmacological inhibition of autophagy worsened mutant myocilin accumulation and exacerbated IOP elevation in Tg-MYOCY437H mice. Remarkably, impaired autophagy was associated with chronic ER stress-induced transcriptional factor CHOP. Deletion of CHOP corrected impaired autophagy, enhanced recognition and degradation of mutant myocilin by autophagy, and reduced glaucoma in Tg-MYOCY437H mice. Stimulating autophagic flux via tat-beclin 1 peptide or torin 2 promoted autophagic degradation of mutant myocilin and reduced elevated IOP in Tg-MYOCY437H mice. Our study provides an alternate treatment strategy for myocilin-associated POAG by correcting impaired autophagy in the TM.
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Affiliation(s)
- Ramesh B. Kasetti
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
| | - Prabhavathi Maddineni
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
| | - Charles Kiehlbauch
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
| | - Shruti Patil
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
| | - Charles C. Searby
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Beth Levine
- Center for Autophagy Research, Department of Internal Medicine
- Howard Hughes Medical Institute, and
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Val C. Sheffield
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Gulab S. Zode
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
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15
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Gallot YS, Bohnert KR. Confounding Roles of ER Stress and the Unfolded Protein Response in Skeletal Muscle Atrophy. Int J Mol Sci 2021; 22:2567. [PMID: 33806433 PMCID: PMC7961896 DOI: 10.3390/ijms22052567] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle is an essential organ, responsible for many physiological functions such as breathing, locomotion, postural maintenance, thermoregulation, and metabolism. Interestingly, skeletal muscle is a highly plastic tissue, capable of adapting to anabolic and catabolic stimuli. Skeletal muscle contains a specialized smooth endoplasmic reticulum (ER), known as the sarcoplasmic reticulum, composed of an extensive network of tubules. In addition to the role of folding and trafficking proteins within the cell, this specialized organelle is responsible for the regulated release of calcium ions (Ca2+) into the cytoplasm to trigger a muscle contraction. Under various stimuli, such as exercise, hypoxia, imbalances in calcium levels, ER homeostasis is disturbed and the amount of misfolded and/or unfolded proteins accumulates in the ER. This accumulation of misfolded/unfolded protein causes ER stress and leads to the activation of the unfolded protein response (UPR). Interestingly, the role of the UPR in skeletal muscle has only just begun to be elucidated. Accumulating evidence suggests that ER stress and UPR markers are drastically induced in various catabolic stimuli including cachexia, denervation, nutrient deprivation, aging, and disease. Evidence indicates some of these molecules appear to be aiding the skeletal muscle in regaining homeostasis whereas others demonstrate the ability to drive the atrophy. Continued investigations into the individual molecules of this complex pathway are necessary to fully understand the mechanisms.
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Affiliation(s)
- Yann S. Gallot
- LBEPS, Univ Evry, IRBA, Université Paris Saclay, 91025 Evry, France
| | - Kyle R. Bohnert
- Kinesiology Department, St. Ambrose University, Davenport, IA 52803, USA
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16
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Zhu X, Wu S, Zeng W, Chen X, Zheng T, Ren J, Ke M. Protective Effects of Rapamycin on Trabecular Meshwork Cells in Glucocorticoid-Induced Glaucoma Mice. Front Pharmacol 2020; 11:1006. [PMID: 32714192 PMCID: PMC7344368 DOI: 10.3389/fphar.2020.01006] [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: 03/23/2020] [Accepted: 06/22/2020] [Indexed: 12/12/2022] Open
Abstract
Glucocorticoid-induced glaucoma (GIG) is a chronic optic neuropathy caused by systemic or topical glucocorticoid (GC) treatment, which could eventually lead to permanent vision loss. To investigate the protective effects of rapamycin (RAP) on the trabecular cells during the development of GIG in mice, the effects of RAP on intraocular pressure (IOP), trabecular ultrastructure, and retinal ganglion cells (RGCs) were examined in C57BL/6J female mice treated with dexamethasone acetate (Dex-Ace). The expression of α-actin in trabecular tissue was detected by immunofluorescence, and the autophagic activity of trabecular cells and the expression of GIG-related myocilin and α-actin were detected by immunoblotting. Our results indicated that Dex-Ace significantly increased IOP at the end of the third week (p < 0.05), while RAP treatment neutralized this elevation of IOP by Dex-Ace. Dex-Ace treatment significantly decreased the RGC numbers (p < 0.05), while synchronous RAP treatment kept the number comparable to control. The outer sheath of elastic fibers became thicker and denser, and the mitochondria of lesions increased in Dex-Ace-treated groups at 4 weeks, while no significant change was observed in the RAP-treated trabecular tissues. Dex-Ace induced myocilin, α-actin, Beclin-1, and LC3-II/LC-I ratio, and lowered p62, while synchronous RAP treatment further activated autophagy and neutralized the induction of myocilin and α-actin. Our studies suggested that RAP protected trabecular meshwork cells by further inducing autophagy way from damages of GC treatment.
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Affiliation(s)
- Xiaolu Zhu
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Shengyu Wu
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Wen Zeng
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xiaomin Chen
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Tian Zheng
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jiangbo Ren
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Min Ke
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, China
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17
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Liu X, Feng B, Vats A, Tang H, Seibel W, Swaroop M, Tawa G, Zheng W, Byrne L, Schurdak M, Chen Y. Pharmacological clearance of misfolded rhodopsin for the treatment of RHO-associated retinitis pigmentosa. FASEB J 2020; 34:10146-10167. [PMID: 32536017 DOI: 10.1096/fj.202000282r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/07/2020] [Accepted: 05/15/2020] [Indexed: 01/20/2023]
Abstract
Rhodopsin mutation and misfolding is a common cause of autosomal dominant retinitis pigmentosa (RP). Using a luciferase reporter assay, we undertook a small-molecule high-throughput screening (HTS) of 68, 979 compounds and identified nine compounds that selectively reduced the misfolded P23H rhodopsin without an effect on the wild type (WT) rhodopsin protein. Further, we found five of these compounds, including methotrexate (MTX), promoted P23H rhodopsin degradation that also cleared out other misfolded rhodopsin mutant proteins. We showed MTX increased P23H rhodopsin degradation via the lysosomal but not the proteasomal pathway. Importantly, one intravitreal injection (IVI) of 25 pmol MTX increased electroretinogram (ERG) response and rhodopsin level in the retinae of RhoP23H/+ knock-in mice at 1 month of age. Additionally, four weekly IVIs increased the photoreceptor cell number in the retinae of RhoP23H/+ mice compared to vehicle control. Our study indicates a therapeutic potential of repurposing MTX for the treatment of rhodopsin-associated RP.
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Affiliation(s)
- Xujie Liu
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bing Feng
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Abhishek Vats
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hong Tang
- Drug Discovery Center, University of Cincinnati, Cincinnati, OH, USA
| | - William Seibel
- Drug Discovery Center, University of Cincinnati, Cincinnati, OH, USA.,Oncology Department, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Manju Swaroop
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Gregory Tawa
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Wei Zheng
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Leah Byrne
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mark Schurdak
- Drug Discovery Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yuanyuan Chen
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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18
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Roy A, Kumar A. ER Stress and Unfolded Protein Response in Cancer Cachexia. Cancers (Basel) 2019; 11:cancers11121929. [PMID: 31817027 PMCID: PMC6966641 DOI: 10.3390/cancers11121929] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 11/26/2019] [Accepted: 11/30/2019] [Indexed: 12/13/2022] Open
Abstract
Cancer cachexia is a devastating syndrome characterized by unintentional weight loss attributed to extensive skeletal muscle wasting. The pathogenesis of cachexia is multifactorial because of complex interactions of tumor and host factors. The irreversible wasting syndrome has been ascribed to systemic inflammation, insulin resistance, dysfunctional mitochondria, oxidative stress, and heightened activation of ubiquitin-proteasome system and macroautophagy. Accumulating evidence suggests that deviant regulation of an array of signaling pathways engenders cancer cachexia where the human body is sustained in an incessant self-consuming catabolic state. Recent studies have further suggested that several components of endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR) are activated in skeletal muscle of animal models and muscle biopsies of cachectic cancer patients. However, the exact role of ER stress and the individual arms of the UPR in the regulation of skeletal muscle mass in various catabolic states including cancer has just begun to be elucidated. This review provides a succinct overview of emerging roles of ER stress and the UPR in cancer-induced skeletal muscle wasting.
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19
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Wang SL, Piao SY, Xu MY, Zhang W, Ma JQ, Hao J, Chi H, Xue ZQ, Ha SP, Zhuang WJ. Evaluating correlation between the ocular biometry and genetic variants of MYOC and ABCA1 with primary angle-closure glaucoma in a cohort from northern China. Int J Ophthalmol 2019; 12:1317-1322. [PMID: 31456923 DOI: 10.18240/ijo.2019.08.13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 06/03/2019] [Indexed: 12/31/2022] Open
Abstract
AIM To investigate whether the gene variants in MYOC and ABCA1 are associated with primary angle-closure glaucoma (PACG) and anterior chamber depth (ACD) and axial length (AL) in samples from northern China. METHODS The present case-control association study consisted of 500 PACG patients and 720 unrelated controls. Each participant was genotyped for eleven single nucleotide polymorphisms (SNPs) in MYOC and ABCA1 genes (rs12076134, rs183532, rs235875 and rs235913 in MYOC, rs2422493, rs2487042, rs2472496, rs2472493, rs2487032, rs2472459 and rs2472519 near ABCA1) using an improved multiplex ligation detection reaction (iMLDR) technique. The genetic association analyses were performed by PLINK using a logistic regression model. The association between genotypes and ocular biometric parameters was performed by SPSS using generalized estimation equation. Bonferroni corrections were implemented and the statistical power was calculated by the Power and Sample Size Calculation. RESULTS Two SNPs rs183532 and rs235875 as well as a haplotype TTC in MYOC were nominally associated with PACG despite the significance was lost after Bonferroni correction. No association was observed between ABCA1 and PACG, neither did the association between these variants and ACD as well as AL. CONCLUSION The present study suggests MYOC and ABCA1 do not play a part in the pathogenesis of PACG as well as the regulation of ocular biometric parameters in a northern Chinese population. Further investigations with large sample size are needed to verify this consequence.
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Affiliation(s)
- Shao-Lin Wang
- Clinical Medical College of Ningxia Medical University, Yinchuan 750001, Ningxia Hui Autonomous Region, China.,Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University For Nationalities), Yinchuan 750011, Ningxia Hui Autonomous Region, China
| | - Shun-Yu Piao
- Clinical Medical College of Ningxia Medical University, Yinchuan 750001, Ningxia Hui Autonomous Region, China
| | - Man-Yun Xu
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University For Nationalities), Yinchuan 750011, Ningxia Hui Autonomous Region, China
| | - Wen Zhang
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University For Nationalities), Yinchuan 750011, Ningxia Hui Autonomous Region, China
| | - Jian-Qing Ma
- Department of Ophthalmology, Wuzhong People's Hospital, Wuzhong 751100, Ningxia Hui Autonomous Region, China
| | - Juan Hao
- Department of Ophthalmology, Taiyuan Central Hospital, Taiyuan 030000, Shanxi Province, China
| | - Hao Chi
- Shandong Academy of Medical Sciences, Jinan University, Jinan 250000, Shandong Province, China
| | - Zhong-Qi Xue
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University For Nationalities), Yinchuan 750011, Ningxia Hui Autonomous Region, China
| | - Shao-Ping Ha
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University For Nationalities), Yinchuan 750011, Ningxia Hui Autonomous Region, China
| | - Wen-Juan Zhuang
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University For Nationalities), Yinchuan 750011, Ningxia Hui Autonomous Region, China
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20
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ER stress activation impairs the expression of circadian clock and clock-controlled genes in NIH3T3 cells via an ATF4-dependent mechanism. Cell Signal 2019; 57:89-101. [PMID: 30703445 DOI: 10.1016/j.cellsig.2019.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 02/06/2023]
Abstract
Endoplasmic reticulum (ER) stress and circadian clockwork signaling pathways mutually regulate various cellular functions, but the details regarding the cross-talk between these pathways in mammalian cells are unclear. In this study, whether perturbation of ER stress signaling affects the cellular circadian clockwork and transcription of clock-controlled genes was investigated in NIH3T3 mouse fibroblasts. An NIH3T3 cell model stably expressing luciferase (Luc) under the control of the Bmal1 clock gene promoter was established using a lentiviral system. Then, Luc activity was monitored in real-time to detect Bmal1-Luc oscillations. The ER stress activators thapsigargin (Tg) and tunicamycin (Tm) markedly reduced Bmal1-Luc oscillation amplitudes and induced phase delay shifts in NIH3T3 cells. Treatment with Tg/Tm activated ER stress signaling by upregulating GRP78, CHOP, ATF6, and ATF4 and simultaneously significantly decreased BMAL1 protein levels and inhibited the transcription of circadian clock (Bmal1, Per2, Nr1d1, and Dbp) and clock-controlled (Scad1, Fgf7, and Arnt) genes. 4-Phenylbutyric acid, an ER stress inhibitor, alleviated the transcriptional repression of the circadian clock genes and partially restored Bmal1-Luc oscillation amplitudes in Tg- or Tm-treated NIH3T3 cells. More importantly, knock-down of ATF4, but not ATF6, in Tg-treated NIH3T3 cells partially rescued Bmal1-Luc oscillation amplitudes and mRNA expression of the four circadian clock genes. Taken together, our study demonstrates that ER stress activation inhibits the transcription of circadian clock and clock-controlled genes via an ATF4-dependent mechanism.
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Afroze D, Kumar A. ER stress in skeletal muscle remodeling and myopathies. FEBS J 2019; 286:379-398. [PMID: 29239106 PMCID: PMC6002870 DOI: 10.1111/febs.14358] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 11/24/2017] [Accepted: 12/07/2017] [Indexed: 12/18/2022]
Abstract
Skeletal muscle is a highly plastic tissue in the human body that undergoes extensive adaptation in response to environmental cues, such as physical activity, metabolic perturbation, and disease conditions. The endoplasmic reticulum (ER) plays a pivotal role in protein folding and calcium homeostasis in many mammalian cell types, including skeletal muscle. However, overload of misfolded or unfolded proteins in the ER lumen cause stress, which results in the activation of a signaling network called the unfolded protein response (UPR). The UPR is initiated by three ER transmembrane sensors: protein kinase R-like endoplasmic reticulum kinase, inositol-requiring protein 1α, and activating transcription factor 6. The UPR restores ER homeostasis through modulating the rate of protein synthesis and augmenting the gene expression of many ER chaperones and regulatory proteins. However, chronic heightened ER stress can also lead to many pathological consequences including cell death. Accumulating evidence suggests that ER stress-induced UPR pathways play pivotal roles in the regulation of skeletal muscle mass and metabolic function in multiple conditions. They have also been found to be activated in skeletal muscle under catabolic states, degenerative muscle disorders, and various types of myopathies. In this article, we have discussed the recent advancements toward understanding the role and mechanisms through which ER stress and individual arms of the UPR regulate skeletal muscle physiology and pathology.
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Affiliation(s)
- Dil Afroze
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
- Department of Immunology and Molecular Medicine, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Kashmir, INDIA
| | - Ashok Kumar
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40202, USA
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22
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Aroca-Aguilar JD, Fernández-Navarro A, Ontañón J, Coca-Prados M, Escribano J. Identification of myocilin as a blood plasma protein and analysis of its role in leukocyte adhesion to endothelial cell monolayers. PLoS One 2018; 13:e0209364. [PMID: 30557320 PMCID: PMC6296516 DOI: 10.1371/journal.pone.0209364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 12/04/2018] [Indexed: 12/27/2022] Open
Abstract
Myocilin is an extracellular glycoprotein with a poorly understood biological function and typically known because of its association with glaucoma. In this study, we analyzed the expression and biological activity of human myocilin in some non-ocular tissues. Western immunoblot showed the presence of myocilin in blood plasma as well as in liver and lymphoid tissues (thymus and lymph node). Quantitative PCR confirmed the expression of MYOC in these lymphoid organs and revealed that its mRNA is also present in T-lymphocytes and leukocytes. In addition, detection of 30 kDa C-terminal myocilin fragments in thymus and liver suggested that myocilin undergoes an in vivo proteolytic processing that might regulate its biological activity. The presence of myocilin in blood was further corroborated by peptide mass fingerprinting of the HPLC-isolated protein, and gross estimation of its concentration by Western immunoblot indicated that it is a medium-abundance serum protein with an approximate concentration of 0.85 mg/ml (15.5 μM). Finally, in vitro analyses indicated that myocilin acts as an anti-adhesive protein for human circulating leukocytes incubated with endothelial cell monolayers. Altogether, these data provide insightful information on new biological properties of myocilin and suggest its putative role as a blood matricellular protein.
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Affiliation(s)
- José-Daniel Aroca-Aguilar
- Laboratorio de Genética Molecular Humana, Facultad de Medicina/Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha, Albacete, Spain
- Cooperative Research Network on Prevention, Early Detection and Treatment of Prevalent Degenerative and Chronic Ocular Pathology (OftaRed), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Fernández-Navarro
- Laboratorio de Genética Molecular Humana, Facultad de Medicina/Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha, Albacete, Spain
| | - Jesús Ontañón
- Servicio de Inmunología, Complejo Hospitalario Universitario de Albacete, Castilla la Mancha, Spain
| | - Miguel Coca-Prados
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT, United States of America
- Fundación de Investigación Oftalmológica Instituto Oftalmológico Fernández-Vega, Oviedo, Spain
| | - Julio Escribano
- Laboratorio de Genética Molecular Humana, Facultad de Medicina/Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla-La Mancha, Albacete, Spain
- Cooperative Research Network on Prevention, Early Detection and Treatment of Prevalent Degenerative and Chronic Ocular Pathology (OftaRed), Instituto de Salud Carlos III, Madrid, Spain
- * E-mail:
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23
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Patel GC, Liu Y, Millar JC, Clark AF. Glucocorticoid receptor GRβ regulates glucocorticoid-induced ocular hypertension in mice. Sci Rep 2018; 8:862. [PMID: 29339763 PMCID: PMC5770444 DOI: 10.1038/s41598-018-19262-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 12/21/2017] [Indexed: 01/26/2023] Open
Abstract
Prolonged glucocorticoid (GC) therapy can cause GC-induced ocular hypertension (OHT), which if left untreated progresses to iatrogenic glaucoma and permanent vision loss. The alternatively spliced isoform of glucocorticoid receptor GRβ acts as dominant negative regulator of GR activity, and it has been shown that overexpressing GRβ in trabecular meshwork (TM) cells inhibits GC-induced glaucomatous damage in TM cells. The purpose of this study was to use viral vectors to selectively overexpress the GRβ isoform in the TM of mouse eyes treated with GCs, to precisely dissect the role of GRβ in regulating steroid responsiveness. We show that overexpression of GRβ inhibits GC effects on MTM cells in vitro and GC-induced OHT in mouse eyes in vivo. Ad5 mediated GRβ overexpression reduced the GC induction of fibronectin, collagen 1, and myocilin in TM of mouse eyes both in vitro and in vivo. GRβ also reversed DEX-Ac induced IOP elevation, which correlated with increased conventional aqueous humor outflow facility. Thus, GRβ overexpression reduces effects caused by GCs and makes cells more resistant to GC treatment. In conclusion, our current work provides the first evidence of the in vivo physiological role of GRβ in regulating GC-OHT and GC-mediated gene expression in the TM.
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Affiliation(s)
- Gaurang C Patel
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Yang Liu
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States.
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24
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Sharif NA. iDrugs and iDevices Discovery Research: Preclinical Assays, Techniques, and Animal Model Studies for Ocular Hypotensives and Neuroprotectants. J Ocul Pharmacol Ther 2018; 34:7-39. [PMID: 29323613 DOI: 10.1089/jop.2017.0125] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Discovery ophthalmic research is centered around delineating the molecular and cellular basis of ocular diseases and finding and exploiting molecular and genetic pathways associated with them. From such studies it is possible to determine suitable intervention points to address the disease process and hopefully to discover therapeutics to treat them. An investigational new drug (IND) filing for a new small-molecule drug, peptide, antibody, genetic treatment, or a device with global health authorities requires a number of preclinical studies to provide necessary safety and efficacy data. Specific regulatory elements needed for such IND-enabling studies are beyond the scope of this article. However, to enhance the overall data packages for such entities and permit high-quality foundation-building publications for medical affairs, additional research and development studies are always desirable. This review aims to provide examples of some target localization/verification, ocular drug discovery processes, and mechanistic and portfolio-enhancing exploratory investigations for candidate drugs and devices for the treatment of ocular hypertension and glaucomatous optic neuropathy (neurodegeneration of retinal ganglion cells and their axons). Examples of compound screening assays, use of various technologies and techniques, deployment of animal models, and data obtained from such studies are also presented.
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Affiliation(s)
- Najam A Sharif
- 1 Global Alliances & External Research , Santen Incorporated, Emeryville, California.,2 Department of Pharmaceutical Sciences, Texas Southern University , Houston, Texas.,3 Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center , Fort Worth, Texas
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25
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Amantini C, Farfariello V, Cardinali C, Morelli MB, Marinelli O, Nabissi M, Santoni M, Bonfili L, Cecarini V, Eleuteri AM, Santoni G. The TRPV1 ion channel regulates thymocyte differentiation by modulating autophagy and proteasome activity. Oncotarget 2017; 8:90766-90780. [PMID: 29207602 PMCID: PMC5710883 DOI: 10.18632/oncotarget.21798] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/20/2017] [Indexed: 12/28/2022] Open
Abstract
Autophagy and the ubiquitin-proteasome system (UPS) control thymus cell homeostasis under resting and endoplasmic reticulum (ER) stress conditions. Several evidence support a cross-talk between UPS and autophagy; abrogation of UPS responses stimulates autophagy, and vice versa the inhibition of autophagy alters the UPS functions. Herein, we found that TRPV1 activation induces ER stress, proteasome dysfunction and autophagy in thymocytes by modulating the expression of UPR-related genes. The TRPV1-mediated autophagy prevents the UPR activation by inhibiting BiP, Grp94 and ERp57 chaperone protein expression. Thymocytes from TRPV1 KO mice display both autophagy and proteasome dysfunctions, resulting in increased apoptotic cells and reduced total DP thymocyte number. In addition, positive selection of thymocytes triggered by anti-TCRβ/CD2 Ab-mediated costimulation induces apoptosis in thymocytes from TRPV1 KO as compared with WT mice. Stimulation of TRPV1 KO thymocytes with anti-TCRβ/CD2 mAbs modulates the expression of CD4 antigen on purified DP thymocytes, with reduced number of mature, single positive (SP) CD4 and increased number of immature SP CD4low and DP CD4lowCD8+ thymocytes, further supporting the intrinsic role of TRPV1 in T cell maturation. Finally, a reduction in CD8+ and CD4+ T cells is evidenced in the peripheral blood and spleen of TRPV1 KO, as compared with WT mice. Therapeutic strategy by restraining or stimulating the TRPV1 expression and functions in thymocytes might represent a new pharmacological tool in the regulation of different inflammatory T cell responses.
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Affiliation(s)
- Consuelo Amantini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Valerio Farfariello
- University of Lille, INSERM U1003 - PHYCEL - Physiologie Cellulaire, Lille, France
| | - Claudio Cardinali
- School of Pharmacy, Experimental Medicine Section, University of Camerino, Camerino, Italy.,Department of Molecular Medicine, Sapienza University, Rome, Italy
| | - Maria Beatrice Morelli
- School of Pharmacy, Experimental Medicine Section, University of Camerino, Camerino, Italy.,Department of Molecular Medicine, Sapienza University, Rome, Italy
| | - Oliviero Marinelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Massimo Nabissi
- School of Pharmacy, Experimental Medicine Section, University of Camerino, Camerino, Italy
| | - Matteo Santoni
- School of Pharmacy, Experimental Medicine Section, University of Camerino, Camerino, Italy
| | - Laura Bonfili
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Valentina Cecarini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Anna Maria Eleuteri
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Giorgio Santoni
- School of Pharmacy, Experimental Medicine Section, University of Camerino, Camerino, Italy
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26
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Bohnert KR, McMillan JD, Kumar A. Emerging roles of ER stress and unfolded protein response pathways in skeletal muscle health and disease. J Cell Physiol 2017; 233:67-78. [PMID: 28177127 DOI: 10.1002/jcp.25852] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 12/17/2022]
Abstract
Skeletal muscle is the most abundant tissue in the human body and can adapt its mass as a consequence of physical activity, metabolism, growth factors, and disease conditions. Skeletal muscle contains an extensive network of endoplasmic reticulum (ER), called sarcoplasmic reticulum, which plays an important role in the regulation of proteostasis and calcium homeostasis. In many cell types, environmental and genetic factors that disrupt ER function cause an accumulation of misfolded and unfolded proteins in the ER lumen that ultimately leads to ER stress. To alleviate the stress and restore homeostasis, the ER activates a signaling network called the unfolded protein response (UPR). The UPR has three arms, which regulate protein synthesis and expression of many ER chaperone and regulatory proteins. However, the role of individual UPR pathways in skeletal muscle has just begun to be investigated. Recent studies suggest that UPR pathways play pivotal roles in muscle stem cell homeostasis, myogenic differentiation, and regeneration of injured skeletal muscle. Moreover, markers of ER stress and the UPR are activated in skeletal muscle in diverse conditions such as exercise, denervation, starvation, high fat diet, cancer cachexia, and aging. Accumulating evidence also suggests that ER stress may have important roles in the pathogenesis of inflammatory myopathies and genetic muscle disorders. The purpose of this review article is to discuss the role and potential mechanisms by which ER stress and the individual arms of the UPR regulate skeletal muscle formation, plasticity, and function in various physiological and pathophysiological conditions.
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Affiliation(s)
- Kyle R Bohnert
- Department of Anatomical Sciences Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Joseph D McMillan
- Department of Anatomical Sciences Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Ashok Kumar
- Department of Anatomical Sciences Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
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27
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Patel GC, Phan TN, Maddineni P, Kasetti RB, Millar JC, Clark AF, Zode GS. Dexamethasone-Induced Ocular Hypertension in Mice: Effects of Myocilin and Route of Administration. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:713-723. [PMID: 28167045 DOI: 10.1016/j.ajpath.2016.12.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 11/24/2022]
Abstract
Glucocorticoid (GC)-induced ocular hypertension (OHT) is a serious adverse effect of prolonged GC therapy that can lead to iatrogenic glaucoma and permanent vision loss. An appropriate mouse model can help us understand precise molecular mechanisms and etiology of GC-induced OHT. We therefore developed a novel, simple, and reproducible mouse model of GC-induced OHT. GC-induced myocilin expression in the trabecular meshwork (TM) has been suggested to play an important role in GC-induced OHT. We further determined whether myocilin contributes to GC-OHT. C57BL/6J mice received weekly periocular conjunctival fornix injections of a dexamethasone-21-acetate (DEX-Ac) formulation. Intraocular pressure (IOP) elevation was relatively rapid and significant, and correlated with reduced conventional outflow facility. Nighttime IOPs were higher in ocular hypertensive eyes compared to daytime IOPs. DEX-Ac treatment led to increased expression of fibronectin, collagen I, and α-smooth muscle actin in the TM in mouse eyes. No changes in body weight indicated no systemic toxicity associated with DEX-Ac treatment. Wild-type mice showed increased myocilin expression in the TM on DEX-Ac treatment. Both wild-type and Myoc-/- mice had equivalent and significantly elevated IOP with DEX-Ac treatment every week. In conclusion, our mouse model mimics many aspects of GC-induced OHT in humans, and we further demonstrate that myocilin does not play a major role in DEX-induced OHT in mice.
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Affiliation(s)
- Gaurang C Patel
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Tien N Phan
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Prabhavathi Maddineni
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Ramesh B Kasetti
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas.
| | - Gulab S Zode
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas.
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28
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Gao FJ, Zhang SH, Li TT, Wu JH, Wu Q. Expression and Distribution of Mesencephalic Astrocyte-Derived Neurotrophic Factor in the Retina and Optic Nerve. Front Hum Neurosci 2017; 10:686. [PMID: 28154531 PMCID: PMC5243802 DOI: 10.3389/fnhum.2016.00686] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 12/23/2016] [Indexed: 02/02/2023] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF), otherwise named Arginine-Rich, Mutated in Early-stage Tumors (ARMET), is a secretory endoplasmic reticulum stress (ERS) protein that is widely expressed in mammalian tissues. To date, little is known about the distribution and expression of MANF in the retina and optic nerve (ON). Therefore, we studied the expression and distribution of MANF in the ON and retina by real-time PCR, immunofluorescence staining and western blotting. Results from rat and mouse were highly consistent in the retina. MANF was detected in both tissues in rat, wherein it was principally localized to the ganglion cell layer (GCL), followed by the inner nuclear layer (INL). The MANF protein levels in the rat retina were 3.33-fold higher than in the rat ON. Additionally, MANF was robustly expressed by retinal ganglion cells (RGCs) in the human retina. In human ON, MANF was partially co-localized with glial fibrillary acidic protein (GFAP), suggesting that it was not restricted to astrocytes. In vitro studies confirmed that MANF could be robustly expressed in RGCs and was found principally within the cytoplasm. Hypoxia can stimulate up-regulation by of MANF expression over time, suggesting that MANF may play a vital role in the functional regulation of RGCs both in health and disease. We believe that the present study improves our understanding of the distribution and expression of MANF in the retina and ON and could help in further analysis of its interact and correlate with the relevant ophthalmic diseases.
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Affiliation(s)
- Feng-Juan Gao
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China
| | - Sheng-Hai Zhang
- Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan UniversityShanghai, China
- Shanghai Key Laboratory of Visual Impairment and RestorationShanghai, China
- Key Laboratory of Myopia, Ministry of Health, Fudan UniversityShanghai, China
| | - Ting-Ting Li
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China
| | - Ji-Hong Wu
- Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan UniversityShanghai, China
- Shanghai Key Laboratory of Visual Impairment and RestorationShanghai, China
- Key Laboratory of Myopia, Ministry of Health, Fudan UniversityShanghai, China
| | - Qiang Wu
- Department of Ophthalmology, Shanghai Jiao Tong University Affiliated Sixth People's HospitalShanghai, China
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29
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Zadoo S, Nguyen A, Zode G, Hulleman JD. A Novel Luciferase Assay For Sensitively Monitoring Myocilin Variants in Cell Culture. Invest Ophthalmol Vis Sci 2016; 57:1939-50. [PMID: 27092720 PMCID: PMC5110263 DOI: 10.1167/iovs.15-18789] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Purpose Primary open angle glaucoma–associated mutations in myocilin (MYOC) cause protein “nonsecretion,” rendering secreted MYOC difficult to detect using conventional techniques. This study focused on developing and using an assay that can quickly and easily detect mutant MYOC secretion. Methods We fused Gaussia luciferase (eGLuc2) to MYOC variants and expressed the constructs in HEK-293T and NTM-5 cells. Secreted and intracellular levels of MYOC eGLuc2 variants were evaluated by Western blotting and compared to untagged and FLAG-tagged MYOC constructs. Secreted and soluble intracellular MYOC eGLuc2 were measured by a GLuc assay. The secretion of nine additional MYOC mutants was assayed in conditioned media from transfected cells to test the applicability of the assay for monitoring other MYOC variants. Results Myocilin eGLuc2 behaved similarly to untagged and FLAG-tagged MYOC with respect to secretion, soluble intracellular levels, and in response to drug treatment. The GLuc assay could sensitively detect Y437H MYOC secretion 30 minutes after media change. Gaussia luciferase fused variants followed anticipated trends; nonpathogenic variants (D208E, G244V) were secreted at wild-type (WT) levels, whereas predicted disease-causing variants (C245Y, G246R, E300K, Y437H, I477N) demonstrated substantial secretion defects. Secretion defects caused by the C245Y, G246R, and Y437H mutations were partially rescued by permissive growth temperature. Interestingly, however, this increase in secretion was independent of newly synthesized protein. Conclusions Fusion of eGLuc2 to MYOC does not significantly change the behavior of MYOC. This newly developed MYOC reporter system can be used to study engineered MYOC variants and potentially to identify modulators of MYOC secretion and function.
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Affiliation(s)
- Serena Zadoo
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Annie Nguyen
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Gulab Zode
- Department of Cell Biology & Immunology and the North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - John D Hulleman
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States 3Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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30
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Bohnert KR, Gallot YS, Sato S, Xiong G, Hindi SM, Kumar A. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia. FASEB J 2016; 30:3053-68. [PMID: 27206451 PMCID: PMC5001510 DOI: 10.1096/fj.201600250rr] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/12/2016] [Indexed: 12/25/2022]
Abstract
Cachexia is a devastating syndrome that causes morbidity and mortality in a large number of patients with cancer. However, the mechanisms of cancer cachexia remain poorly understood. Accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes stress. The ER responds to this stress through activating certain pathways commonly known as the unfolding protein response (UPR). The main function of UPR is to restore homeostasis, but excessive or prolonged activation of UPR can lead to pathologic conditions. In this study, we examined the role of ER stress and UPR in regulation of skeletal muscle mass in naïve conditions and during cancer cachexia. Our results demonstrate that multiple markers of ER stress are highly activated in skeletal muscle of Lewis lung carcinoma (LLC) and Apc(Min/+) mouse models of cancer cachexia. Treatment of mice with 4-phenylbutyrate (4-PBA), a chemical chaperon and a potent inhibitor of ER stress, significantly reduced skeletal muscle strength and mass in both control and LLC-bearing mice. Blocking the UPR also increased the proportion of fast-type fibers in soleus muscle of both control and LLC-bearing mice. Inhibition of UPR reduced the activity of Akt/mTOR pathway and increased the expression of the components of the ubiquitin-proteasome system and autophagy in LLC-bearing mice. Moreover, we found that the inhibition of UPR causes severe atrophy in cultured myotubes. Our study provides initial evidence that ER stress and UPR pathways are essential for maintaining skeletal muscle mass and strength and for protection against cancer cachexia.-Bohnert, K. R., Gallot, Y. S., Sato, S., Xiong, G., Hindi, S. M., Kumar, A. Inhibition of ER stress and unfolding protein response pathways causes skeletal muscle wasting during cancer cachexia.
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Affiliation(s)
- Kyle R Bohnert
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Yann S Gallot
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Shuichi Sato
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Guangyan Xiong
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Sajedah M Hindi
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Ashok Kumar
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
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31
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Sebag J, Sadun AA, Pierce EA. Paradigm Shifts in Ophthalmic Diagnostics. TRANSACTIONS OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY 2016; 114:WP1. [PMID: 28008209 PMCID: PMC5141845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
PURPOSE Future advances in ophthalmology will see a paradigm shift in diagnostics from a focus on dysfunction and disease to better measures of psychophysical function and health. Practical methods to define genotypes will be increasingly important and non-invasive nanotechnologies are needed to detect molecular changes that predate histopathology. METHODS This is not a review nor meant to be comprehensive. Specific topics have been selected to illustrate the principles of important paradigm shifts that will influence the future of ophthalmic diagnostics. It is our impression that future evaluation of vision will go beyond visual acuity to assess ocular health in terms of psychophysical function. The definition of disease will incorporate genotype into what has historically been a phenotype-centric discipline. Non-invasive nanotechnologies will enable a paradigm shift from disease detection on a cellular level to a sub-cellular molecular level. RESULTS Vision can be evaluated beyond visual acuity by measuring contrast sensitivity, color vision, and macular function, as these provide better insights into the impact of aging and disease. Distortions can be quantified and the psychophysical basis of vision can be better evaluated than in the past by designing tests that assess particular macular cell function(s). Advances in our understanding of the genetic basis of eye diseases will enable better characterization of ocular health and disease. Non-invasive nanotechnologies can assess molecular changes in the lens, vitreous, and macula that predate visible pathology. Oxygen metabolism and circulatory physiology are measurable indices of ocular health that can detect variations of physiology and early disease. CONCLUSIONS This overview of paradigm shifts in ophthalmology suggests that the future will see significant improvements in ophthalmic diagnostics. The selected topics illustrate the principles of these paradigm shifts and should serve as a guide to further research and development. Indeed, successful implementation of these paradigm shifts in ophthalmology may provide useful guidance for similar developments in all of healthcare.
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Affiliation(s)
- J Sebag
- Dr. Sebag: VMR Institute for Vitreous Macula Retina, Huntington Beach, CA; Dr. Sadun: Doheny Eye Institute/UCLA, Los Angeles, CA; Dr. Pierce: Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School
| | - Alfredo A Sadun
- Dr. Sebag: VMR Institute for Vitreous Macula Retina, Huntington Beach, CA; Dr. Sadun: Doheny Eye Institute/UCLA, Los Angeles, CA; Dr. Pierce: Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School
| | - Eric A Pierce
- Dr. Sebag: VMR Institute for Vitreous Macula Retina, Huntington Beach, CA; Dr. Sadun: Doheny Eye Institute/UCLA, Los Angeles, CA; Dr. Pierce: Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School
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