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Hart CC, Lee YI, Xie J, Gao G, Lin BL, Hammers DW, Sweeney HL. Potential limitations of micro-dystrophin gene therapy for Duchenne muscular dystrophy. JCI Insight 2024:e165869. [PMID: 38713520 DOI: 10.1172/jci.insight.165869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2024] Open
Abstract
Clinical trials delivering high doses of adeno-associated viruses (AAVs) expressing truncated dystrophin molecules (micro-dystrophins) are underway for individuals with Duchenne muscular dystrophy (DMD). We examined the efficiency and efficacy of this strategy with four micro-dystrophin constructs (three in clinical trials and a variant of the largest clinical construct), in a severe mouse model of DMD, using doses of AAV comparable to those used in the clinical trials. We achieved high levels of micro-dystrophin expression in striated muscle with cardiac expression ~10 fold higher than that observed in skeletal muscle. Significant, albeit incomplete, correction of the skeletal muscle disease was observed. Surprisingly, a lethal acceleration of cardiac disease progression occurred with two of the micro-dystrophins. The detrimental impact on the heart appears to be caused by the high levels of micro-dystrophin resulting in variable competition (dependent on the design of the micro-dystrophin) between micro-dystrophin and utrophin at the cardiomyocyte membrane. There may also be a contribution from an overloading of protein degradation. The significance of these observations for patients currently being treated with AAV-micro-dystrophin therapies is unclear since the levels of expression being achieved in the DMD hearts are unknown. However, it suggests that micro-dystrophin treatments need to avoid excessively high levels of expression in the heart and cardiac function should be carefully monitored in these patients.
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Affiliation(s)
- Cora C Hart
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Young Il Lee
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Jun Xie
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, United States of America
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, United States of America
| | - Brian L Lin
- Department of Cell Biology, 7 Neurobiology, and Anatomy, Medical College of Wisconsin, Milwakee, United States of America
| | - David W Hammers
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - H Lee Sweeney
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
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Höök P, Lee YI, Sweeney HL. Myosin VI powers self-organization of branched contractile actin network. Biochem Biophys Res Commun 2024; 691:149329. [PMID: 38042035 DOI: 10.1016/j.bbrc.2023.149329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 11/23/2023] [Indexed: 12/04/2023]
Abstract
The actomyosin cytoskeletal network is responsible for a variety of fundamental cellular processes. Assembly and maintenance of actin networks involve an array of associated regulatory proteins for polymerization, branching, crosslinking and contractility-driven self-organization. In this study, we make the unexpected discovery in vitro that myosin VI and myosin X, motor proteins specialized in vesicle transport and filopodia formation, are capable of crosslinking and self-organizing actin into higher-order contractile structures in the absence of other actin-associated proteins. Moreover, myosin VI alone can initiate actin elongation and branching, and assemble branched force-generating networks from crosslinked actin polymers. Additional architectural control is provided by the actin crosslinking proteins α-actinin and fascin. Our data identify critical stages of tension-mediated connectivity in network development and provide a model system for further exploration of the nonequilibrium mechanics of actomyosin self-organization.
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Affiliation(s)
- Peter Höök
- Department of Pharmacology & Therapeutics and the Myology Institute, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Young Il Lee
- Department of Pharmacology & Therapeutics and the Myology Institute, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - H Lee Sweeney
- Department of Pharmacology & Therapeutics and the Myology Institute, University of Florida College of Medicine, Gainesville, FL, 32610, USA.
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Chen X, Arciola JM, Lee YI, Wong PHP, Yin H, Tao Q, Jin Y, Qin X, Sweeney HL, Park H. Myo10 tail is crucial for promoting long filopodia. J Biol Chem 2024; 300:105523. [PMID: 38043799 PMCID: PMC10790087 DOI: 10.1016/j.jbc.2023.105523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/22/2023] [Accepted: 11/24/2023] [Indexed: 12/05/2023] Open
Abstract
Filopodia are slender cellular protrusions containing parallel actin bundles involved in environmental sensing and signaling, cell adhesion and migration, and growth cone guidance and extension. Myosin 10 (Myo10), an unconventional actin-based motor protein, was reported to induce filopodial initiation with its motor domain. However, the roles of the multifunctional tail domain of Myo10 in filopodial formation and elongation remain elusive. Herein, we generated several constructs of Myo10-full-length Myo10, Myo10 with a truncated tail (Myo10 HMM), and Myo10 containing four mutations to disrupt its coiled-coil domain (Myo10 CC mutant). We found that the truncation of the tail domain decreased filopodial formation and filopodial length, while four mutations in the coiled-coil domain disrupted the motion of Myo10 toward filopodial tips and the elongation of filopodia. Furthermore, we found that filopodia elongated through multiple elongation cycles, which was supported by the Myo10 tail. These findings suggest that Myo10 tail is crucial for promoting long filopodia.
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Affiliation(s)
- Xingxiang Chen
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | | | - Young Il Lee
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, USA
| | - Pak Hung Philip Wong
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Haoran Yin
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Quanqing Tao
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Yuqi Jin
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Xianan Qin
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - H Lee Sweeney
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, USA; Myology Institute, University of Florida College of Medicine, Gainesville, Florida, USA.
| | - Hyokeun Park
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China; Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China.
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Canon L, Kikuti C, Planelles-Herrero VJ, Lin T, Mayeux F, Sirkia H, Lee YI, Heidsieck L, Velikovsky L, David A, Liu X, Moussaoui D, Forest E, Höök P, Petersen KJ, Morgan TE, Di Cicco A, Sirés-Campos J, Derivery E, Lévy D, Delevoye C, Sweeney HL, Houdusse A. How myosin VI traps its off-state, is activated and dimerizes. Nat Commun 2023; 14:6732. [PMID: 37872146 PMCID: PMC10593786 DOI: 10.1038/s41467-023-42376-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 10/10/2023] [Indexed: 10/25/2023] Open
Abstract
Myosin VI (Myo6) is the only minus-end directed nanomotor on actin, allowing it to uniquely contribute to numerous cellular functions. As for other nanomotors, the proper functioning of Myo6 relies on precise spatiotemporal control of motor activity via a poorly defined off-state and interactions with partners. Our structural, functional, and cellular studies reveal key features of myosin regulation and indicate that not all partners can activate Myo6. TOM1 and Dab2 cannot bind the off-state, while GIPC1 binds Myo6, releases its auto-inhibition and triggers proximal dimerization. Myo6 partners thus differentially recruit Myo6. We solved a crystal structure of the proximal dimerization domain, and show that its disruption compromises endocytosis in HeLa cells, emphasizing the importance of Myo6 dimerization. Finally, we show that the L926Q deafness mutation disrupts Myo6 auto-inhibition and indirectly impairs proximal dimerization. Our study thus demonstrates the importance of partners in the control of Myo6 auto-inhibition, localization, and activation.
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Affiliation(s)
- Louise Canon
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Carlos Kikuti
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Vicente J Planelles-Herrero
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Tianming Lin
- Department of Pharmacology & Therapeutics and the Myology Institute, University of Florida College of Medicine, PO Box 100267, Gainesville, Florida, 32610-0267, USA
| | - Franck Mayeux
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Helena Sirkia
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Young Il Lee
- Department of Pharmacology & Therapeutics and the Myology Institute, University of Florida College of Medicine, PO Box 100267, Gainesville, Florida, 32610-0267, USA
| | - Leila Heidsieck
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Léonid Velikovsky
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Amandine David
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Xiaoyan Liu
- Department of Pharmacology & Therapeutics and the Myology Institute, University of Florida College of Medicine, PO Box 100267, Gainesville, Florida, 32610-0267, USA
| | - Dihia Moussaoui
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - Emma Forest
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
- École Nationale Supérieure de Chimie de Montpellier, 240 Avenue du Professeur Emile Jeanbrau, 34090, Montpellier, France
| | - Peter Höök
- Department of Pharmacology & Therapeutics and the Myology Institute, University of Florida College of Medicine, PO Box 100267, Gainesville, Florida, 32610-0267, USA
| | - Karl J Petersen
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | | | - Aurélie Di Cicco
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005, Paris, France
| | - Julia Sirés-Campos
- Structure et Compartimentation Membranaire, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | | | - Daniel Lévy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005, Paris, France
| | - Cédric Delevoye
- Structure et Compartimentation Membranaire, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France
| | - H Lee Sweeney
- Department of Pharmacology & Therapeutics and the Myology Institute, University of Florida College of Medicine, PO Box 100267, Gainesville, Florida, 32610-0267, USA.
| | - Anne Houdusse
- Structural Motility, UMR 144 CNRS/Curie Institute, PSL Research University, 26 rue d'Ulm, 75258, Paris cedex 05, France.
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Lee YI, Cacciani N, Wen Y, Zhang X, Hedström Y, Thompson W, Larsson L. Direct electrical stimulation impacts on neuromuscular junction morphology on both stimulated and unstimulated contralateral soleus. J Cachexia Sarcopenia Muscle 2023. [PMID: 37060275 DOI: 10.1002/jcsm.13235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 03/06/2023] [Accepted: 03/15/2023] [Indexed: 04/16/2023] Open
Abstract
BACKGROUND There is increasing evidence of crosstalk between organs. The neuromuscular junction (NMJ) is a peripheral chemical synapse whose function and morphology are sensitive to acetylcholine (ACh) release and muscle depolarization. In an attempt to improve our understanding of NMJ plasticity and muscle crosstalk, the effects of unilateral direct electrical stimulation of a hindlimb muscle on the NMJ were investigated in rats exposed long-term post-synaptic neuromuscular blockade. METHODS Sprague Dawley rats were subjected to post-synaptic blockade of neuromuscular transmission by systemic administration of α-cobrotoxin and mechanically ventilated for up to 8 days and compared with untreated sham operated controls and animals exposed to unilateral chronic electrical stimulation 12 h/day for 5 or 8 days. RESULTS NMJs produced axonal and glial sprouts (growth of processes that extend beyond the confines of the synapse defined by high-density aggregates of acetylcholine receptors [AChRs]) in response to post-synaptic neuromuscular blockade, but less than reported after peripheral denervation or pre-synaptic blockade. Direct electrical soleus muscle stimulation reduced the terminal Schwann cell (tSC) and axonal sprouting in both stimulated and non-stimulated contralateral soleus. Eight days chronic stimulation reduced (P < 0.001) the number of tSC sprouts on stimulated and non-stimulated soleus from 6.7 ± 0.5 and 6.9 ± 0.5 sprouts per NMJ, respectively, compared with 10.3 ± 0.9 tSC per NMJ (P < 0.001) in non-stimulated soleus from rats immobilized for 8 days. A similar reduction of axonal sprouts (P < 0.001) was observed in stimulated and non-stimulated contralateral soleus in response to chronic electrical stimulation. RNAseq-based gene expression analyses confirmed a restoring effect on both stimulated and unstimulated contralateral muscle. The cross-over effect was paralleled by increased cytokine/chemokine levels in stimulated and contralateral unstimulated muscle as well as in plasma. CONCLUSIONS Motor axon terminals and terminal Schwann cells at NMJs of rats subjected to post-synaptic neuromuscular blockade exhibited sprouting responses. These axonal and glial responses were likely dampened by a muscle-derived myokines released in an activity-dependent manner with both local and systemic effects.
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Affiliation(s)
- Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, USA
- Department of Pharmacology & Therapeutics, College of Medicine, University of Florida Myology Institute, University of Florida, Gainesville, FL, USA
| | - Nicola Cacciani
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet, Stockholm, Sweden
| | - Ya Wen
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet, Stockholm, Sweden
| | - Xiang Zhang
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Yvette Hedström
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet, Stockholm, Sweden
| | - Wesley Thompson
- Department of Biology, Texas A&M University, College Station, TX, USA
- Section of Molecular Cell and Developmental Biology, The University of Texas, Austin, TX, USA
| | - Lars Larsson
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Neuroscience, Section of Clinical Neurophysiology, Karolinska Institutet, Stockholm, Sweden
- Viron Molecular Medicine Institute, Boston, MA, USA
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Lee YI, Seo M, Cho KJ. Demodex Blepharitis: An Analysis of Nine Patients. Korean J Parasitol 2022; 60:429-432. [PMID: 36588421 PMCID: PMC9806504 DOI: 10.3347/kjp.2022.60.6.429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 10/05/2022] [Indexed: 12/29/2022]
Abstract
Inflammatory eyelid symptoms are common in primary care and there have been several reports on Demodex blepharitis. In the present study, we evaluate the 9 patients with Demodex blepharitis, who showed inflammation of the eyelids, dry eye, and cylindrical dandruff at the base of the eyelashes. The causative species from all patients was Demodex folliculorum of either the adult or nymph stage. Two patients had recurrent chalazion and 3 patients had keratitis. Weekly lid scrubs with 50% tee tree oil were performed for 6 weeks. After treatment, the symptoms of blepharitis and keratitis had improved in all patients. This case report provides clinical reference source for the proper treatment of ocular demodicosis.
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Affiliation(s)
- Young Il Lee
- Department of Anatomy, College of Medicine, Dankook University, Cheonan 31116,
Korea
| | - Min Seo
- Department of Parasitology, College of Medicine, Dankook University, Cheonan 31116,
Korea
| | - Kyong Jin Cho
- Department of Ophthalmology, Dankook University College of Medicine, Cheonan 31116,
Korea,Corresponding author ()
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Yu WN, Lin HF, Lee YI, Shia WC, Sung WW, Yeh CM, Lin YM. PBK Expression Is Associated With Prognosis of Patients With Oral Squamous Cell Carcinoma Treated With Radiotherapy: A Retrospective Study. Anticancer Res 2021; 41:2177-2182. [PMID: 33813430 DOI: 10.21873/anticanres.14991] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/05/2021] [Accepted: 03/10/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM To investigate the impact of PDZ-binding kinase (PBK) on the clinical outcome of patients with oral squamous cell carcinoma (OSCC) who received radiotherapy. PATIENTS AND METHODS PBK immunoreactivity of cancer specimens obtained from 179 patients with primary OSCC was analyzed by immunohistochemistry. RESULTS High PBK expression in tumor cells tended to be associated with advanced N-stage. The 5-year survival rate was greater for patients with high total PBK expression than in those with low PBK expression. After adjustment, high PBK remained associated with a favorable outcome. In subgroups according to tumor stage, the prognostic role was significant in patients with stage III/IV rather than those with stage I/II disease. CONCLUSION We suggest that PBK expression should be used as an independent prognostic marker for patients with OSCC treated with radiotherapy, especially for those with advanced-stage disease.
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Affiliation(s)
- Wan-Nien Yu
- Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, Changhua, Taiwan, R.O.C
| | - Heng-Fu Lin
- Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, Changhua, Taiwan, R.O.C
| | - Y I Lee
- School of Medicine, Chung Shan Medical University, Taichung, Taiwan, R.O.C
| | - Wei-Chung Shia
- Cancer Research Center, Department of Research, Changhua Christian Hospital, Changhua, Taiwan, R.O.C
| | - Wen-Wei Sung
- School of Medicine, Chung Shan Medical University, Taichung, Taiwan, R.O.C.,Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan, R.O.C.,Department of Urology, Chung Shan Medical University Hospital, Taichung, Taiwan, R.O.C
| | - Chung-Min Yeh
- Department of Surgical Pathology, Changhua Christian Hospital, Changhua, Taiwan, R.O.C.,Department of Medical Technology, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli, Taiwan, R.O.C
| | - Yueh-Min Lin
- School of Medicine, Chung Shan Medical University, Taichung, Taiwan, R.O.C.; .,Department of Surgical Pathology, Changhua Christian Hospital, Changhua, Taiwan, R.O.C
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Lee YI, Rimer M. Wesley J. Thompson (1947-2019). Front Mol Neurosci 2020; 13:91. [PMID: 32595450 PMCID: PMC7303338 DOI: 10.3389/fnmol.2020.00091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 04/30/2020] [Indexed: 11/16/2022] Open
Affiliation(s)
- Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Mendell Rimer
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, Bryan, TX, United States
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Hastings RL, Massopust RT, Haddix SG, Lee YI, Thompson WJ. Exclusive vital labeling of myonuclei for studying myonuclear arrangement in mouse skeletal muscle tissue. Skelet Muscle 2020; 10:15. [PMID: 32381068 PMCID: PMC7204059 DOI: 10.1186/s13395-020-00233-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 04/23/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The arrangement of myonuclei in skeletal muscle tissue has long been used as a biomarker for muscle health, but there is a dearth of in vivo exploration of potential effects of myonuclear organization on the function and regeneration of skeletal muscle because traditional nuclear stains are performed on postmortem tissue. Therefore, we sought a transgenic method to produce a selective and persistent myonuclear label in whole muscles of living mice. METHODS We bred together a mouse line with skeletal muscle fiber-selective expression of Cre recombinase and a second mouse line with a Cre-inducible fluorescently tagged histone protein to generate a mouse line that produces a myonuclear label suitable for vital imaging and histology of fixed tissue. We tested the effectiveness of this vital label in three conditions known to generate abnormal myonuclear positioning. First, we injured myofibers of young mice with cardiotoxin. Second, this nuclear label was bred into a murine model of Duchenne muscular dystrophy. Finally, we examined old mice from this line that have undergone the natural aging process. Welch's t test was used to compare wild type and transgenic mice. RESULTS The resulting mouse line transgenically produces a vital red fluorescent label of myonuclei, which facilitates their in vivo imaging in skeletal muscle tissue. Transgenic fluorescent labeling of myonuclei has no significant effect on skeletal muscle function, as determined by twitch and tetanic force recordings. In each muscle examined, including those under damaged, dystrophic, and aged conditions, the labeled myonuclei exhibit morphology consistent with established literature, and reveal a specialized arrangement of subsynaptic myonuclei at the neuromuscular junction. CONCLUSIONS Taken together, our results demonstrate that this mouse line provides a versatile tool to selectively visualize myonuclei within both living and fixed preparations of healthy, injured, diseased, and aged muscles.
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Affiliation(s)
- Robert Louis Hastings
- Texas A&M Institute for Neuroscience, College Station, TX, USA.
- Department of Biology, Texas A&M University, College Station, TX, USA.
| | - Ryan T Massopust
- Texas A&M Institute for Neuroscience, College Station, TX, USA
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Seth G Haddix
- Texas A&M Institute for Neuroscience, College Station, TX, USA
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Wesley J Thompson
- Texas A&M Institute for Neuroscience, College Station, TX, USA
- Department of Biology, Texas A&M University, College Station, TX, USA
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Lee YI. Developmental neuromuscular synapse elimination: Activity-dependence and potential downstream effector mechanisms. Neurosci Lett 2019; 718:134724. [PMID: 31877335 DOI: 10.1016/j.neulet.2019.134724] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/18/2019] [Accepted: 12/23/2019] [Indexed: 12/12/2022]
Abstract
Synaptic connections initially formed during nervous system development undergo a significant transformation during nervous system maturation. Such maturation is essential for the proper architecture and function of the nervous system. Developmental synaptic transformation includes "synapse elimination," a process in which multiple immature presynaptic inputs converge at and compete for control of a common postsynaptic target. This developmental synaptic remodeling is best understood at mammalian neuromuscular junctions. It is well established that neuromuscular activity provides the impetus for the pruning of redundant motor axon inputs. Despite the dominant influence neuromuscular activity exerts on developmental synapse elimination, however, the downstream mechanisms of neuromuscular activity that affect synapse elimination remain poorly understood. Conversely, although several cellular and molecular effector mechanisms are known to impact synapse elimination, it is unclear whether they are modulated by neuromuscular activity. This review discusses how the motor neurons, synaptic glia and muscle fibers each contributes to the developmental phenomenon, and speculates how neuromuscular activity may modulate these contributions.
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Affiliation(s)
- Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA.
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Lee YI. Differences in the constituent fiber types contribute to the intermuscular variation in the timing of the developmental synapse elimination. Sci Rep 2019; 9:8694. [PMID: 31213646 PMCID: PMC6582271 DOI: 10.1038/s41598-019-45090-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/28/2019] [Indexed: 11/09/2022] Open
Abstract
The emergence of a mature nervous system requires a significant refinement of the synaptic connections initially formed during development. Redundant synaptic connections are removed in a process known as synapse elimination. Synapse elimination has been extensively studied at the rodent neuromuscular junction (NMJ). Although several axons initially converge onto each postsynaptic muscle fiber, all redundant inputs are removed during early postnatal development until a single motor neuron innervates each NMJ. Neuronal activity as well as synaptic glia influence the course of synapse elimination. It is, however, unclear whether target muscle fibers are more than naïve substrates in this process. I examined the influence of target myofiber contractile properties on synapse elimination. The timing of redundant input removal in muscles examined correlates strongly with their proportion of slow myofibers: muscles with more slow fibers undergo elimination more slowly. Moreover, this intermuscular difference in the timing of synapse elimination appears to result from local differences in the rate of elimination on fast versus slow myofibers. These results, therefore, imply that differences in the constituent fiber types help account for the variation in the timing of the developmental synapse elimination between muscles and show that the muscle plays a role in the process.
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Affiliation(s)
- Young Il Lee
- Department of Biology, Texas A&M University, College Station, TX, 77843, Texas, USA.
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Lee YI, Kim YG, Pyeon HJ, Ahn JC, Logan S, Orock A, Joo KM, Lőrincz A, Deák F. Dysregulation of the SNARE-binding protein Munc18-1 impairs BDNF secretion and synaptic neurotransmission: a novel interventional target to protect the aging brain. GeroScience 2019; 41:109-123. [PMID: 31041658 PMCID: PMC6544690 DOI: 10.1007/s11357-019-00067-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/15/2019] [Indexed: 12/19/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) has a central role in maintaining and strengthening neuronal connections and to stimulate neurogenesis in the adult brain. Decreased levels of BDNF in the aging brain are thought to usher cognitive impairment. BDNF is stored in dense core vesicles and released through exocytosis from the neurites. The exact mechanism for the regulation of BDNF secretion is not well understood. Munc18-1 (STXBP1) was found to be essential for the exocytosis of synaptic vesicles, but its involvement in BDNF secretion is not known. Interestingly, neurons lacking munc18-1 undergo severe degeneration in knock-out mice. Here, we report the effects of BDNF treatment on the presynaptic terminal using munc18-1-deficient neurons. Reduced expression of munc18-1 in heterozygous (+/-) neurons diminishes synaptic transmitter release, as tested here on individual synaptic connections with FM1-43 fluorescence imaging. Transduction of cultured neurons with BDNF markedly increased BDNF secretion in wild-type but was less effective in munc18-1 +/- cells. In turn, BDNF enhanced synaptic functions and restored the severe synaptic dysfunction induced by munc18-1 deficiency. The role of munc18-1 in the synaptic effect of BDNF is highlighted by the finding that BDNF upregulated the expression of munc18-1 in neurons, consistent with enhanced synaptic functions. Accordingly, this is the first evidence showing the functional effect of BDNF in munc18-1 deficient synapses and about the direct role of munc18-1 in the regulation of BDNF secretion. We propose a molecular model of BDNF secretion and discuss its potential as therapeutic target to prevent cognitive decline in the elderly.
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Affiliation(s)
- Young Il Lee
- Department of Anatomy, College of Medicine, Dankook University, Cheonan, 330-714, South Korea
| | - Yun Gi Kim
- Department of Anatomy, College of Medicine, Dankook University, Cheonan, 330-714, South Korea
- Department of Nanobiomedical Science and WCU Research Center, Dankook University, Cheonan, 330-714, South Korea
| | - Hee Jang Pyeon
- Department of Nanobiomedical Science and WCU Research Center, Dankook University, Cheonan, 330-714, South Korea
- Department of Anatomy and Cell Biology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jin Chul Ahn
- Department of Biomedical Science, Dankook University, Cheonan, 330-714, South Korea
- Biomedical Translational Research Institute, Dankook University, Cheonan, 330-714, South Korea
| | - Sreemathi Logan
- Departments of Geriatric Medicine and Physiology, University Oklahoma HSC, Oklahoma City, OK, USA
- Reynolds Oklahoma Center on Aging, Oklahoma City, OK, USA
- Oklahoma Center for Neuroscience, Oklahoma City, OK, USA
| | - Albert Orock
- Departments of Geriatric Medicine and Physiology, University Oklahoma HSC, Oklahoma City, OK, USA
- Reynolds Oklahoma Center on Aging, Oklahoma City, OK, USA
- Oklahoma Center for Neuroscience, Oklahoma City, OK, USA
| | - Kyeung Min Joo
- Department of Anatomy and Cell Biology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
- Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Andrea Lőrincz
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Florida State College at Jacksonville, 4500 Capper Rd, Jacksonville, FL, 32218, USA
| | - Ferenc Deák
- Departments of Geriatric Medicine and Physiology, University Oklahoma HSC, Oklahoma City, OK, USA.
- Reynolds Oklahoma Center on Aging, Oklahoma City, OK, USA.
- Oklahoma Center for Neuroscience, Oklahoma City, OK, USA.
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
- Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma HSC, 975 N. E. 10th Street/SLY-BRC 1309-B, Oklahoma City, OK, 73104-5419, USA.
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Larsson L, Degens H, Li M, Salviati L, Lee YI, Thompson W, Kirkland JL, Sandri M. Sarcopenia: Aging-Related Loss of Muscle Mass and Function. Physiol Rev 2019; 99:427-511. [PMID: 30427277 DOI: 10.1152/physrev.00061.2017] [Citation(s) in RCA: 667] [Impact Index Per Article: 133.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Sarcopenia is a loss of muscle mass and function in the elderly that reduces mobility, diminishes quality of life, and can lead to fall-related injuries, which require costly hospitalization and extended rehabilitation. This review focuses on the aging-related structural changes and mechanisms at cellular and subcellular levels underlying changes in the individual motor unit: specifically, the perikaryon of the α-motoneuron, its neuromuscular junction(s), and the muscle fibers that it innervates. Loss of muscle mass with aging, which is largely due to the progressive loss of motoneurons, is associated with reduced muscle fiber number and size. Muscle function progressively declines because motoneuron loss is not adequately compensated by reinnervation of muscle fibers by the remaining motoneurons. At the intracellular level, key factors are qualitative changes in posttranslational modifications of muscle proteins and the loss of coordinated control between contractile, mitochondrial, and sarcoplasmic reticulum protein expression. Quantitative and qualitative changes in skeletal muscle during the process of aging also have been implicated in the pathogenesis of acquired and hereditary neuromuscular disorders. In experimental models, specific intervention strategies have shown encouraging results on limiting deterioration of motor unit structure and function under conditions of impaired innervation. Translated to the clinic, if these or similar interventions, by saving muscle and improving mobility, could help alleviate sarcopenia in the elderly, there would be both great humanitarian benefits and large cost savings for health care systems.
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Affiliation(s)
- Lars Larsson
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Hans Degens
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Meishan Li
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Leonardo Salviati
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Young Il Lee
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Wesley Thompson
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - James L Kirkland
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Marco Sandri
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
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Lee YI, Thompson WJ, Harlow ML. Schwann cells participate in synapse elimination at the developing neuromuscular junction. Curr Opin Neurobiol 2017; 47:176-181. [PMID: 29121585 DOI: 10.1016/j.conb.2017.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/06/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022]
Abstract
During the initial stages of innervation of developing skeletal muscles, the terminal branches of axons from multiple motor neurons form neuromuscular junctions (NMJs) on a small region of each muscle fiber, the motor endplate. Subsequently, the number of axonal inputs at the endplate region is reduced so that, at maturity, each muscle fiber is innervated by the terminals of a single motor neuron. The Schwann cells associated with the axon terminals are involved in the removal of these synapses but do not select the axon that is ultimately retained on each fiber. Schwann cells perform this function by disconnecting terminal branches from the myofiber surface and by attacking them phagocytically. Here we discuss how this behavior is regulated and argue that such regulation is not unique to development of neuromuscular innervation but is also expressed in the response of the mature NMJ to various manipulations and pathologies.
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Affiliation(s)
- Young Il Lee
- Department of Biology and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, United States.
| | - Wesley J Thompson
- Department of Biology and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, United States; University of Texas (adjunct), Department of Neuroscience, Austin, TX 78712, United States
| | - Mark L Harlow
- Department of Biology and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, United States
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15
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Lee DS, Lee YI, Ahn JB, Kim MJ, Kim JH, Kim NH, Hwang JH, Kim DW, Lee CG, Song TW. Massive pulmonary hemorrhage in enterovirus 71-infected hand, foot, and mouth disease. Korean J Pediatr 2015; 58:112-5. [PMID: 25861335 PMCID: PMC4388973 DOI: 10.3345/kjp.2015.58.3.112] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 10/17/2013] [Accepted: 01/20/2014] [Indexed: 11/27/2022]
Abstract
Hand, foot, and mouth disease (HFMD) is an acute, mostly self-limiting infection. Patients usually recover without any sequelae. However, a few cases are life threatening, especially those caused by enterovirus 71 (EV71). A 12-month-old boy was admitted to a primary hospital with high fever and vesicular lesions of the mouth, hands, and feet. After 3 days, he experienced 3 seizure episodes and was referred to our hospital. On admission, he was conscious and his chest radiograph was normal. However, 6 hours later, he suddenly lost consciousness and had developed a massive pulmonary hemorrhage that continued until his death. He experienced several more intermittent seizures, and diffuse infiltration of both lung fields was observed on chest radiography. Intravenous immunoglobulin, dexamethasone, cefotaxime, leukocyte-depleted red blood cells, fresh frozen plasma, inotropics, vitamin K, and endotracheal epinephrine were administered. The patient died 9 hours after intubation, within 3 days from fever onset. EV71 subgenotype C4a was isolated retrospectively from serum and nasopharyngeal swab by real-time reverse transcription-polymerase chain reaction. Here, we report a fatal case of EV71-associated HFMD with sudden-onset massive pulmonary hemorrhage and suspected encephalitis.
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Affiliation(s)
- Dong Seong Lee
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Young Il Lee
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Jeong Bae Ahn
- Division of Vaccine Research, Center for Infectious Disease, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon, Korea
| | - Mi Jin Kim
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Jae Hyun Kim
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Nam Hee Kim
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Jong Hee Hwang
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Dong Wook Kim
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Chong Guk Lee
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | - Tae Won Song
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
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16
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Lee YI, Ye BJ. Underwater and hyperbaric medicine as a branch of occupational and environmental medicine. Ann Occup Environ Med 2013; 25:39. [PMID: 24472678 PMCID: PMC3923352 DOI: 10.1186/2052-4374-25-39] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 12/11/2013] [Indexed: 11/29/2022] Open
Abstract
Exposure to the underwater environment for occupational or recreational purposes is increasing. As estimated, there are around 7 million divers active worldwide and 300,000 more divers in Korea. The underwater and hyperbaric environment presents a number of risks to the diver. Injuries from these hazards include barotrauma, decompression sickness, toxic effects of hyperbaric gases, drowning, hypothermia, and dangerous marine animals. For these reasons, primary care physicians should understand diving related injuries and assessment of fitness to dive. However, most Korean physicians are unfamiliar with underwater and hyperbaric medicine (UHM) in spite of scientific and practical values. From occupational and environmental medicine (OEM) specialist’s perspective, we believe that UHM should be a branch of OEM because OEM is an area of medicine that deals with injuries caused by physical and biological hazards, clinical toxicology, occupational diseases, and assessment of fitness to work. To extend our knowledge about UHM, this article will review and update on UHM including barotrauma, decompression illness, toxicity of diving gases and fitness for diving.
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Affiliation(s)
| | - Byeong Jin Ye
- Department of Occupational & Environmental Medicine, College of Medicine, Kosin University, 34-1 Amnam-dong, Seo-gu, Busan 602-702, South Korea.
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17
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Bokara KK, Kim JY, Lee YI, Yun K, Webster TJ, Lee JE. Biocompatability of carbon nanotubes with stem cells to treat CNS injuries. Anat Cell Biol 2013; 46:85-92. [PMID: 23869255 PMCID: PMC3713283 DOI: 10.5115/acb.2013.46.2.85] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/11/2013] [Accepted: 06/12/2013] [Indexed: 12/14/2022] Open
Abstract
Cases reporting traumatic injuries to the brain and spinal cord are extended range of disorders that affect a large percentage of the world's population. But, there are only few effective treatments available for central nervous system (CNS) injuries because the CNS is refractory to axonal regeneration and relatively inaccessible to many pharmacological treatments. The use of stem cell therapy in regenerative medicine has been extensively examined to replace lost cells during CNS injuries. But, given the complexity of CNS injuries oxidative stress, toxic byproducts, which prevails in the microenvironment during the diseased condition, may limit the survival of the transplanted stem cells affecting tissue regeneration and even longevity. Carbon nanotubes (CNT) are a new class of nanomaterials, which have been shown to be promising in different areas of nanomedicine for the prevention, diagnosis and therapy of certain diseases, including CNS diseases. In particular, the use of CNTs as substrates/scaffolds for supporting the stem cell differentiation has been an area of active research. Single-walled and multi-walled CNT's have been increasingly used as scaffolds for neuronal growth and more recently for neural stem cell growth and differentiation. This review summarizes recent research on the application of CNT-based materials to direct the differentiation of progenitor and stem cells toward specific neurons and to enhance axon regeneration and synaptogenesis for the effective treatment of CNS injuries. Nonetheless, accumulating data support the use of CNTs as a biocompatible and permissive substrate/scaffold for neural cells and such application holds great potential in neurological research.
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Affiliation(s)
- Kiran Kumar Bokara
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
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Kim YG, Kim JW, Pyeon HJ, Hyun JK, Hwang JY, Choi SJ, Lee JY, Deák F, Kim HW, Lee YI. Differential stimulation of neurotrophin release by the biocompatible nano-material (carbon nanotube) in primary cultured neurons. J Biomater Appl 2013; 28:790-7. [DOI: 10.1177/0885328213481637] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In order to develop novel, effective therapies for central nervous system regeneration, it is essential to better understand the role of neurotrophic factors and to design, accordingly, better artificial scaffolds to support both neurite outgrowth and synapse formation. Both nerve growth factor and brain-derived neurotrophic factor are major factors in neural survival, development, synaptogenesis, and synaptic connectivity of primary cultured neurons. As a prime candidate coating material for such neural cultures, carbon nanotubes offer unique structural, mechanical, and electrical properties. In this study, carbon nanotubes coated glass-coverslips were used as the matrix of a primary neural culture system used to investigate the effects of carbon nanotubes on neurite outgrowth and nerve growth factor/brain-derived neurotrophic factor release and expression. For these purposes, we performed comparative analyses of primary cultured neurons on carbon nanotubes coated, non-coated, and Matrigel-coated coverslips. The morphological findings showed definite carbon nanotubes effects on the neurite outgrowths and synaptogenic figures in both cortical and hippocampal neurons when compared with the non-coated negative control. Although the carbon nanotubes did not change neurotrophin expression levels, it stimulated brain-derived neurotrophic factor release into the media from both types of neurons. Accordingly, we suggest a different mechanism of action between carbon nanotubes and Matrigel in relation to the specific neurotrophic factors. Since carbon nanotubes supply long-term extracellular molecular cues for the survival and neurite outgrowths of cultured neurons, the results from this study will contribute to an understanding of carbon nanotubes biological effects and provide new insight into their role in the secretion of neurotrophic factors.
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Affiliation(s)
- Yun Gi Kim
- Department of Nanobiomedical Science and WCU Research Center, Dankook University, Cheonan, South Korea
| | - Jong Wan Kim
- Department of Nanobiomedical Science and WCU Research Center, Dankook University, Cheonan, South Korea
| | - Hee Jang Pyeon
- Department of Nanobiomedical Science and WCU Research Center, Dankook University, Cheonan, South Korea
| | - Jung Keun Hyun
- Department of Nanobiomedical Science and WCU Research Center, Dankook University, Cheonan, South Korea
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
| | - Ji-Young Hwang
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
| | - Seong-Jun Choi
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
| | - Ja-Yeon Lee
- Department of Nanobiomedical Science and WCU Research Center, Dankook University, Cheonan, South Korea
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
| | - Ferenc Deák
- Reynolds Oklahoma Center on Aging and Department of Geriatric Medicine, University of Oklahoma HSC, Oklahoma City, OK, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | - Hae-Won Kim
- Department of Nanobiomedical Science and WCU Research Center, Dankook University, Cheonan, South Korea
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
| | - Young Il Lee
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Anatomy, College of Medicine, Dankook University, Cheonan, South Korea
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Lee YI, Mikesh M, Smith I, Rimer M, Thompson W. Muscles in a mouse model of spinal muscular atrophy show profound defects in neuromuscular development even in the absence of failure in neuromuscular transmission or loss of motor neurons. Dev Biol 2011; 356:432-44. [PMID: 21658376 DOI: 10.1016/j.ydbio.2011.05.667] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 05/20/2011] [Accepted: 05/23/2011] [Indexed: 11/16/2022]
Abstract
A mouse model of the devastating human disease "spinal muscular atrophy" (SMA) was used to investigate the severe muscle weakness and spasticity that precede the death of these animals near the end of the 2nd postnatal week. Counts of motor units to the soleus muscle as well as of axons in the soleus muscle nerve showed no loss of motor neurons. Similarly, neither immunostaining of neuromuscular junctions nor the measurement of the tension generated by nerve stimulation gave evidence of any significant impairment in neuromuscular transmission, even when animals were maintained up to 5days longer via a supplementary diet. However, the muscles were clearly weaker, generating less than half their normal tension. Weakness in 3 muscles examined in the study appears due to a severe but uniform reduction in muscle fiber size. The size reduction results from a failure of muscle fibers to grow during early postnatal development and, in soleus, to a reduction in number of fibers generated. Neuromuscular development is severely delayed in these mutant animals: expression of myosin heavy chain isoforms, the elimination of polyneuronal innervation, the maturation in the shape of the AChR plaque, the arrival of SCs at the junctions and their coverage of the nerve terminal, the development of junctional folds. Thus, if SMA in this particular mouse is a disease of motor neurons, it can act in a manner that does not result in their death or disconnection from their targets but nonetheless alters many aspects of neuromuscular development.
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Affiliation(s)
- Young Il Lee
- Section of Molecular Cell and Developmental Biology, The University of Texas, Austin, TX 78712, USA.
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Lee YI, Park MH, Bae JH, Lee SE, Song KW, Kim TH, Lee YH, Yang CW. Loading behavior of Pt nanoparticles on the surface of multiwalled carbon nanotubes having defects formed via microwave treatment. J Nanosci Nanotechnol 2011; 11:479-483. [PMID: 21446480 DOI: 10.1166/jnn.2011.3216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We developed a simple and efficient method to load Pt nanoparticles (NPs) uniformly on defects generated in multiwalled CNTs (MWCNTs) without using reduction agents or organic reagents. Defects on the surfaces of MWCNTs were artificially generated by microwave treatment at various exposure times. Nucleation of Pt NPs occurs on the defect sites spontaneously due to an innate electropotential difference. Because of the correlation between defects and Pt NPs, we were able to control the size of Pt NPs by changing defect size, quantity and distribution, which was confirmed by Raman spectroscopy and TEM. After microwave treatment for 3 min, more uniform and smaller Pt NPs were observed. Also, the defects via microwave treatment make adhesion of Pt NPs stronger, which can be helpful to improve the reliability for applications. Finally, the methanol oxidation behavior of MWCNTs with Pt NPs was examined by cyclic voltammetry (CV).
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Affiliation(s)
- Y I Lee
- School of Advanced Materials Science and Engineering, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan University, Suwon 440-746, Korea
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21
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Park MH, Lee JW, Lee YI, Lee JH, Hwang JH, Kim HK, Yang CW. Patterning of catalysts for the selective growth of carbon nanotubes using laser irradiation of nickel nitrate. J Nanosci Nanotechnol 2011; 11:602-605. [PMID: 21446506 DOI: 10.1166/jnn.2011.3226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We developed a simple method to produce patterned catalysts for the growth of carbon nanotubes (CNTs) on Si substrate using laser irradiation of Ni nitrate. We found that Ni nitrate can easily be decomposed into Ni oxide by KrF laser irradiation and that unexposed Ni nitrate can be removed using deionized (DI) water. Once we obtained patterned Ni oxide, we were able to synthesize multi-walled CNTs using a conventional thermal CVD. This new method does not require any photoresist or vacuum processes. Not only is the method compatible with low-temperature and large-area fabrication, it also significantly reduces the total processing steps required for conventional lithographic patterning technology. A detailed investigation of the decomposition process of this patterned catalyst and the microstructure of the patterned multi-walled CNTs was carried out using IR, SEM and TEM.
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Affiliation(s)
- M H Park
- School of Advanced Materials Science & Engineering and Center for Nanotubes & Nanostructured Composites, Sungkyunkwan University, Suwon 440-746, Korea
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Hong KS, Kim EC, Bang SH, Chung CH, Lee YI, Hyun JK, Lee HH, Jang JH, Kim TI, Kim HW. Bone regeneration by bioactive hybrid membrane containing FGF2 within rat calvarium. J Biomed Mater Res A 2010; 94:1187-94. [PMID: 20694985 DOI: 10.1002/jbm.a.32799] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study examined the bone regeneration potential of a novel hybrid membrane consisting of collagen and nano-bioactive glass (nBG) incorporating basic fibroblast growth factor (FGF2) for use in guided bone regeneration. nBG was added to a reconstitution of collagen at a concentration of 30%, and the hybrid was formulated into a thin membrane. FGF2 (50 microg/ml) was adsorbed to the hybrid membrane. This level of FGF2 was found to be the optimal concentration to stimulate osteoblastic differentiation in vitro. Three membrane groups, including pure collagen, collagen-nBG hybrid and its combination with FGF2 were implanted within a rat calvarium defect (phi = 5 mm) for a period of 3 weeks. Histomorphometric analysis was carried out to evaluate the bone regeneration within the defect. The results showed that the defect in the collagen-nBG-FGF2 membrane was recovered almost completely, while partial recovery was observed in the other membrane groups (collagen and collagen-BG). However, there was little defect recovery in the blank control. The new bone formation was as high as approximately 60, approximately 45, and approximately 30% of the defect treated with the collagen-nBG-FGF2, collagen-BG, and collagen, respectively, whilst only 4% of new bone was observed in the blank control. Overall, the nBG was shown to stimulate bone formation of the collagen membrane, and FGF2 synergistically accelerated the bone regeneration within a rat calvarium defect.
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Affiliation(s)
- Ki Seok Hong
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
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Park JS, Hong SJ, Kim HY, Yu HS, Lee YI, Kim CH, Kwak SJ, Jang JH, Hyun JK, Kim HW. Evacuated Calcium Phosphate Spherical Microcarriers for Bone Regeneration. Tissue Eng Part A 2010; 16:1681-91. [DOI: 10.1089/ten.tea.2009.0624] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jeong-Soo Park
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Biochemistry, College of Medicine, Dankook University, Cheonan, South Korea
| | - Seok-Jung Hong
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Nanobiomedical Science & WCU Research Center, Dankook University Graduate School, Cheonan, South Korea
| | - Hee-Young Kim
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
| | - Hye-Sun Yu
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Nanobiomedical Science & WCU Research Center, Dankook University Graduate School, Cheonan, South Korea
| | - Young Il Lee
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Anatomy, College of Medicine, Dankook University, Cheonan, South Korea
| | - Chul-Hwan Kim
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Oral and Maxillofacial Surgery, School of Dentistry, Dankook University, Cheonan, South Korea
| | - Sahng-June Kwak
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Biochemistry, College of Medicine, Dankook University, Cheonan, South Korea
| | - Jun-Hyeog Jang
- Department of Biochemistry, College of Medicine, Inha University, Incheon, South Korea
| | - Jung Keun Hyun
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Nanobiomedical Science & WCU Research Center, Dankook University Graduate School, Cheonan, South Korea
- Department of Rehabilitation Medicine, College of Medicine, Dankook University, Cheonan, South Korea
| | - Hae-Won Kim
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, South Korea
- Department of Nanobiomedical Science & WCU Research Center, Dankook University Graduate School, Cheonan, South Korea
- Department of Biomaterials Science, School of Dentistry, Dankook University, Cheonan, South Korea
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Hyun JK, Lee YI, Son YJ, Park JS. Serial changes in bladder, locomotion, and levels of neurotrophic factors in rats with spinal cord contusion. J Neurotrauma 2010; 26:1773-82. [PMID: 19203225 DOI: 10.1089/neu.2007.0485] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The aims of this study were to evaluate the evolution of the neurogenic bladder after spinal cord contusion and to correlate changes in bladder function with locomotor function and levels of neurotrophic factors. The MASCIS impactor was used to cause a mild contusion injury of the lower thoracic spinal cord of Sprague-Dawley rats. Rats were divided into four groups according to the length of time from injury to sacrifice, at 4, 14, 28, and 56 days after injury. Gait analysis was performed each week, and urodynamic study was performed just before sacrifice. Basso, Beattie, and Bresnahan (BBB) and coupling scores showed gradual recovery, as did the urinary voiding pattern and bladder volume; some parameters of micturition reached normal ranges. Brain-derived neurotrophic factor (BDNF) levels in the spinal cord, as detected by enzyme-linked immunosorbent assay, decreased with time, whereas neurotrophin-3 (NT-3) levels remained unchanged. The micturition pattern, bladder volume, and locomotor function continued to recover during the time of observation; BDNF levels in the spinal cord and bladder were inversely correlated with BBB scores and the restoration of bladder volume. We conclude that urodynamic changes in the bladder correlate with locomotion recovery but not with the levels of BDNF or NT-3 after modified mild contusion injury in rats.
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Affiliation(s)
- Jung Keun Hyun
- Department of Rehabilitation Medicine, Dankook University, Cheonan, Korea.
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Hyun JK, Lee YI, Son YJ, Park JS. Serial Changes in Bladder, Locomotion, and in Levels of Neurotrophic Factors in Rats with Spinal Cord Contusion. J Neurotrauma 2009. [DOI: 10.1089/neu.2007-0485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Kim MJ, Lim HS, Yoo YB, Lee YI, Hahm DH, Lee HJ, Jung KW, Kim JW, Yoe SM, Chung DC, Chang YP. Expression of CD95 and CD95L on astrocytes in the CA1 area of the immature rat hippocampus after hypoxia-ischemia injury. Comp Med 2007; 57:581-589. [PMID: 18246871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The immature brain is affected profoundly by hypoxia-ischemia (HI) injury, which can lead to permanent neurologic sequelae in survivors. Neuronal degeneration after HI injury usually is achieved through apoptosis. Both CD95 and its natural ligand, CD95L, which are key molecules in the regulation of apoptosis, are constitutively expressed by neurons and astrocytes during embryonic and early postnatal stages. Further, CD95 or CD95L may have a functional relationship in glial cells and lead to apoptosis of these cells. The hippocampus, especially the CA1 area, is particularly susceptible to HI injury. We therefore investigated the temporal and spatial alterations in CD95 and CD95L expression in the CA1 area of 7-d-old rats after unilateral ligation of the carotid artery. Using immunohistochemistry and Western blotting, we showed that expression of CD95 and CD95L in the hippocampus peaked at 12 h and then decreased. In addition, we used terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick end-labeling to demonstrate apoptosis among CD95- and CD95L-reactive cells. Our findings show that increases in the expression of CD95 and CD95L after HI injury may involve astrocytic apoptosis in the 7-d-old rat hippocampus, and these molecules may act as targets or inducers of cell death.
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Affiliation(s)
- Myeung Ju Kim
- Department of Anatomy, Dankook University College of Medicine, Cheon-an, Chungnam, South Korea
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Abstract
Few studies have focused on the correlation between p21 expression and survival for patients with non-small cell lung carcinoma (NSCLC), and the results are not consistent. We investigated the expression of p21 in 90 cases of NSCLC to evaluate the correlation between the p21 expression level and the clinicopathologic characteristics with patient survival. p21 was expressed in the nuclei of all the NSCLCs. The percentage of immunoreactive cells varied from 1% to 70%. All the patients were subdivided into a high and a low p21 expression group on the basis of the median percentage (17.05). There was no significant correlation between the p21 expression level and age, gender, histologic type, histologic grade, or stage. Using uni- and multivariate analyses, survival was significantly associated with gender, stage, and the p21 expression level. The survival rate for the high p21 expression group was higher than that for the low p21 expression group in the entire patient group, and especially for stage II and III patients, males, adenocarcinomas, or p53-positive tumors. Our findings showed that high p21 expression was an independent prognostic factor for NSCLC. p21 may be useful for determining the candidates for adjuvant therapies and also for selecting the appropriate chemotherapeutic agents.
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Affiliation(s)
- Mi Seon Kwon
- Department of Pathology, Dankook University College of Medicine, 16-5 Anseo-dong, Cheonan, Chungnam 330-714, Republic of Korea.
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Lee YI, Park J, Lee YH, Han BG. Nitric Oxide Is Implicated in Apoptotic Cell Death Induced by H2O2 in C6 Cells. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.2001.tb05691.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chang YP, Kim MJ, Lee YI, Im IJ, Cho JJ, Kim JW, Yeo SM. Fas/FasL expression in the hippocampus of neonatal rat brains follwing hypoxic-ischemic injury. Korean J Pediatr 2006. [DOI: 10.3345/kjp.2006.49.2.198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Young Pyo Chang
- Department of Pediatrics, Dankook University, Cheonan, Korea
- Institute of Life Science, College of Medicine, Dankook University, Cheonan, Korea
| | - Myeung Ju Kim
- Department of Anatomy, Dankook University, Cheonan, Korea
| | - Young Il Lee
- Department of Anatomy, Dankook University, Cheonan, Korea
| | - Ik Je Im
- Department of Pediatrics, Dankook University, Cheonan, Korea
| | - Jae Ju Cho
- Department of Pediatrics, Dankook University, Cheonan, Korea
| | - Jong-Wan Kim
- Department of Biological Science, Dankook University, Cheonan, Korea
| | - Sung Moon Yeo
- Department of Biological Science, Dankook University, Cheonan, Korea
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Kim DS, Lee IS, Jang CS, Kang SY, Song HS, Lee YI, Seo YW. Development of AFLP-derived STS markers for the selection of 5-methyltryptophan-resistant rice mutants. Plant Cell Rep 2004; 23:71-80. [PMID: 15064855 DOI: 10.1007/s00299-004-0790-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Revised: 02/24/2004] [Accepted: 02/24/2004] [Indexed: 05/24/2023]
Abstract
To increase the specific free amino acid content in the japonica rice (Oryza sativa L.) cultivar Donganbyeo, mutant cell lines resistant to growth inhibition by 5-methyltryptophan (5MT) were selected from embryo-cultured callus irradiated with 50 Gy gamma-rays. Four 5MT-resistant homozygous M4 lines, MRI-40, MRI-116, MRII-8, and MRII-12, were obtained. The mean content of nine free essential amino acids were 70.1, 72.5, 31.7, and 35.4% greater than the original variety in these four mutant lines, respectively. For AFLP analysis, 8 EcoRI (+2) and 8 MseI (+3) primers used in 45 primer combinations generated a total of 3,684 bands with a mean of 82 bands, of which 361 (9.8%) were clearly polymorphic with the control cultivar, the four 5MT-resistant mutants, and five sensitive lines. The lines were grouped into three clusters through cluster analysis using unweighted pair grouping method of averages. The 36 polymorphic PCR products present only in the four homozygous 5MT-resistant lines were cloned and sequenced, and 10 of these sequenced products were converted into sequence tagged site (STS) markers. These STS primer sets were designated OSMR1-OSMR10. Six STS primer sets (OSMR1, OSMR2, OSMR3, OSMR4, OSMR5, and OSMR6) generated a single monomorphic PCR product identical in size to the original AFLP fragments. The broad applicability of these STS markers for the screening of 5MT resistance was evaluated with seven putative 5MT-resistant M2 plants (PM-1 to PM-7). Four STS markers (OSMR1, OSMR2, OSMR4, and OSMR5) out of six STS primer sets were revealed as polymorphic products between the control cultivar and the seven M2 plants. These markers can be utilized for the fine selection of 5MT resistance in rice, and this PCR-screening technique is less time-consuming, less labor-intensive, and more accurate and reliable than selection based solely on phenotypic evaluation involving soaking in 5MT solutions.
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Affiliation(s)
- D S Kim
- Department of Radiation Plant Breeding and Genetics, Korea Atomic Energy Research Institute, P.O. Box 105, 305-600, Yuseong-Gu, Daejeon, South Korea.
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Park JY, Park JH, Park HJ, Lee JY, Lee YI, Lee K, Chun SY. Stage-dependent regulation of ovarian pituitary adenylate cyclase-activating polypeptide mRNA levels by GnRH in cultured rat granulosa cells. Endocrinology 2001; 142:3828-35. [PMID: 11517159 DOI: 10.1210/endo.142.9.8384] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The present study was designed to test whether GnRH regulates pituitary adenylate cyclase-activating polypeptide mRNA levels in a stage-dependent manner during follicle development in the rat ovary. The granulosa cells of preovulatory and immature follicles obtained from PMSG- and estrogen-treated rats, respectively, were cultured in serum-free conditions in the presence of various hormones. GnRH receptor mRNA expression was detected in both preovulatory and immature granulosa cells and was down-regulated by gonadotropins. Treatment of preovulatory granulosa cells with GnRH agonist stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in a dose-dependent manner. In situ hybridization analysis of cultured preovulatory follicles revealed that GnRH-induced pituitary adenylate cyclase- activating polypeptide signals were detected in granulosa cells, but not thecal cells. In immature granulosa cells, cotreatment with GnRH agonist suppressed FSH-stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in a dose-dependent manner, whereas treatment with GnRH alone had no effect. Furthermore, treatment with GnRH antagonist inhibited LH-induced pituitary adenylate cyclase-activating polypeptide gene expression in preovulatory granulosa cells, whereas it stimulated FSH-induced pituitary adenylate cyclase-activating polypeptide gene expression in immature granulosa cells. Interestingly, GnRH-stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in preovulatory granulosa cells was inhibited by arachidonyltri fluoromethyl ketone, an inhibitor of phospholipase A(2), but not by an inhibitor of protein kinase A or C. Lastly, treatment of preovulatory follicles with pituitary adenylate cyclase-activating polypeptide antagonist suppressed GnRH-stimulated progesterone production during 6--9 h of culture. Taken together, these results demonstrate the stage-dependent regulation of pituitary adenylate cyclase-activating polypeptide mRNA levels by GnRH, the stimulatory and inhibitory effect in granulosa cells of preovulatory and immature follicles, respectively.
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Affiliation(s)
- J Y Park
- Hormone Research Center, Chonnam National University, Kwangju 500-757, Republic of Korea
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Lee YI, Kim SO, Kwon HJ, Park JG, Sohn MJ, Jeong SS. Phosphorylation of purified recombinant hepatitis B virus-X protein by mitogen-activated protein kinase and protein kinase C in vitro. J Virol Methods 2001; 95:1-10. [PMID: 11377708 DOI: 10.1016/s0166-0934(00)00282-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The recombinant human hepatitis B virus-X protein (rhHBx) has been expressed as inclusion bodies in Escherichia coli and purified. By sequential dialysis of urea, rhHBx was folded into the native structure, which was demonstrated by both the efficacy of its transcriptional activation of the adenovirus major late promoter, fluorescence and circular dichroism (CD) analysis. The increase in CD values at 220 nm and a corresponding blue shift of the intrinsic fluorescence emission confirmed the ability of HBx to refold in lower concentrations of urea to produce the active protein. After purification and renaturation, the rhHBx protein was found to be phosphorylated by protein kinase C (PKC) and mitogen-activated protein kinase (MAPK). In vivo phosphorylation of HBx was also demonstrated. Although PKC and MAPK enhance the HBx phosphorylation in vitro, neither protein kinase A nor caseine kinase II (CKII) phosphorylate HBx protein, though there are possible substrate residues of both kinases in HBx protein. Phosphoamino acid analysis of the total acid hydrolyzed HBx showed that serine residues can be phosphorylated by PKC or MAPK.
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Affiliation(s)
- Y I Lee
- Liver Cell Signal Transduction Research Unit, Bioscience Research Division, Korea Research Institute of Bioscience and Biotechnology, 305-606, Taejon, South Korea.
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Lee YI, Kang-Park S, Do SI, Lee YI. The hepatitis B virus-X protein activates a phosphatidylinositol 3-kinase-dependent survival signaling cascade. J Biol Chem 2001; 276:16969-77. [PMID: 11278872 DOI: 10.1074/jbc.m011263200] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The hepatitis B virus-X (HBx) protein is known as a multifunctional protein that not only coactivates transcription of viral and cellular genes but coordinates the balance between proliferation and programmed cell death, by inducing or blocking apoptosis. In this study the role of the HBx protein in activation of phosphatidylinositol 3-kinase (PI3K) was investigated as a possible cause of anti-apoptosis in liver cells. HBx relieved serum deprivation-induced and pro-apoptic stimuli-induced apoptosis in Chang liver (CHL) cells. Treatment with 1-d-3-deoxy-3-fluoro-myo-inositol, an antagonist to PI3K, which blocks the formation of 3'-phosphorylated phosphatidyl inositol in CHL cells transformed by HBx (CHL-X) but not normal Chang liver (CHL) cells, showed a marked loss of viability with evidence of apoptosis. Similarly, treatment with wortmannin, an inhibitor of PI3K, stimulated apoptosis in HBx-transformed CHL cells but not in normal cells, confirming that HBx blocks apoptosis through the PI3K pathway. The serine 47 threonine kinase, Akt, one of the downstream effectors of PI3K-dependent survival signaling was 2-fold higher in HBx-transformed CHL (CHL-X) cells than CHL cells. Phosphorylation of Akt at serine 473 and Bad at serine 136 were induced by HBx, which were specifically blocked by wortmannin and dominant negative mutants of Akt and Bad, respectively. We also demonstrated that HBx inhibits caspase 3 activity and HBx down-regulation of caspase 3 activity was blocked by the PI3K inhibitor. Regions required for PI3K phosphorylation on the HBx protein overlap with the known transactivation domains. HBx blocks apoptosis induced by serum withdrawal in CHL cells in a p53-independent manner. The results indicate that, unlike other DNA tumor viruses that block apoptosis by inactivating p53, the hepatitis B virus achieves protection from apoptotic death through a HBx-PI3K-Akt-Bad pathway and by inactivating caspase 3 activity that is at least partially p53-independent in liver cells. Moreover, these data suggest that modulation of the PI3K activity may represent a potential therapeutic strategy to counteract the occurrence of apoptosis in human hepatocellular carcinoma.
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Affiliation(s)
- Y I Lee
- Liver Cell Signal Transduction Research Unit, Animal Cell and Medical Glycobiology Research Unit, Bioscience Research Division, Korea Research Institute of Bioscience and Biotechnology, P. O. Box 115, Yusong, Taejon 305-600, Korea
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Lee S, Park U, Lee YI. Hepatitis C virus core protein transactivates insulin-like growth factor II gene transcription through acting concurrently on Egr1 and Sp1 sites. Virology 2001; 283:167-77. [PMID: 11336542 DOI: 10.1006/viro.2001.0892] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The possibility that hepatitis C virus core gene product (HCV-core) acts as a transactivator in insulin-like growth factor II (IGF-II) gene transcription was tested. HCV-core protein increases endogenous IGF-II expression from promoter 4 (P4) of the IGF-II gene through two cis-acting elements: Sp1 and Egr1 binding sites. Sp1 and Egr1 both bind to IGF-II P4 and functionally cooperate in mediating the maximal activity of IGF-II P4. HCV-core protein induced the binding of Sp1 and Egr1 on its binding sites on IGF-II P4. In addition, Sp1 and Egr1 were stimulated to phosphorylate by HCV-core, and its DNA binding activity was up-regulated upon HCV-core transfection. Transfection with HCV-core in HepG2 cells stimulated the membrane translocation of protein kinase C (PKC) and the treatment of HCV-core transfected cells with calphostin C, a PKC inhibitor, blocked induction of Sp1 and Egr1 DNA binding activity, and eventually transcriptional transactivations of the IGF-II gene. Increasing the DNA binding activity of the phosphorylated form of Sp1 and Egr1 might be an important mechanism for regulating IGF-II gene expression and for promoting cell division during hepatic carcinogenesis. These results indicate that HCV-core functions as a positive regulator of IGF-II transcription through the PKC pathway and that Sp1 and Egr1 are direct targets of the transcriptional regulation of the IGF-II gene which plays an important role in hepatitis C virus pathogenesis during the formation of hepatocellular carcinoma (HCC).
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Affiliation(s)
- S Lee
- Liver Cell Signal Transduction Laboratory, Bioscience Research Division, Korea Research Institute of Bioscience and Biotechnology, Taejon, Korea 305-606
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Kang-Park S, Lee JH, Shin JH, Lee YI. Activation of the IGF-II gene by HBV-X protein requires PKC and p44/p42 map kinase signalings. Biochem Biophys Res Commun 2001; 283:303-7. [PMID: 11327698 DOI: 10.1006/bbrc.2001.4767] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We have recently shown that HBx protein, one of the causative agents of hepatocellular carcinomas, regulates Sp1 mediated transcription of insulin-like growth factor II promoter 4 (Lee et al. (1998) Oncogene 16, 2367-2380). Here we show that PKC and p44/p42MAPK signalings are required for the HBx-induced Sp1-mediated IGF-II P4 transcriptional activity since (i) PKC activation by PMA or PKC expression vector increases Sp1 phosphorylation and P4 activity in HBx-transfected HepG2 cells; (ii) PKC inhibition by PKC inhibitor Gö6976 reduces Sp1 phosphorylation, P4 activity, and IGF-II mRNA in HBx-transfected HepG2 cells; and (iii) the inhibition of MEK activation by U0126 reduces Sp1 phosphorylation, P4 activity and IGF-II mRNA in HBx-transfected HepG2 cells. These results demonstrate that PKC and p44/p42 MAPK cascades are the essential signaling pathways in Sp1-mediated IGF-II gene activation by HBx.
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MESH Headings
- Carbazoles/pharmacology
- Carcinoma, Hepatocellular/etiology
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- Enzyme Inhibitors/pharmacology
- Gene Expression Regulation, Neoplastic/drug effects
- Hepatitis B Antigens/genetics
- Hepatitis B Antigens/toxicity
- Humans
- Indoles/pharmacology
- Insulin-Like Growth Factor II/genetics
- Liver Neoplasms/etiology
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/metabolism
- Phosphorylation
- Promoter Regions, Genetic
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Neoplasm/genetics
- RNA, Neoplasm/metabolism
- Signal Transduction
- Sp1 Transcription Factor/metabolism
- Trans-Activators/genetics
- Trans-Activators/toxicity
- Transcriptional Activation
- Transfection
- Tumor Cells, Cultured
- Viral Regulatory and Accessory Proteins
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Affiliation(s)
- S Kang-Park
- Liver Cell Signal Transduction Laboratory, Korea Research Institute of Bioscience and Biotechnology, Taejon, 305-606, Korea
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Lee YI, Jo SC, Tao WA, Cooks RG. Metal-assisted esterification: glutaric acid-iron(II) complexes in the gas phase. Rapid Commun Mass Spectrom 2001; 15:484-488. [PMID: 11268132 DOI: 10.1002/rcm.254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Transition metal ions are routinely used to assist organic reactions; however, direct detection of the intermediates in such reactions is uncommon. Here, we demonstrate a transition metal ion-assisted reaction between glutaric acid (L) and methanol, using electrospray ionization mass spectrometry (ESI-MS). Esterification of glutaric acid does not occur in aqueous methanol solution under ESI conditions, but the FeII-bound acid cluster, [FeII L2 - H]+, adds methanol and dehydrates to give rise to an abundant product ion with a 14 Da increased mass. The occurrence of methyl esterification is supported by collision-induced dissociation and isotopic labeling data, which indicate that the sequence by which the product ion is generated is loss of water, followed by the addition of methanol. Electrospray ionization conditions, specifically the tube lens offset voltage, strongly affect the reaction efficiency, presumably through control of the dehydration process. Other transition metal ions, such as NiII, ZnII, CoII and CuII, also show distinctive metal-assisted reactions.
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Affiliation(s)
- Y I Lee
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
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Lee YI, Lee S, Das GC, Park US, Park SM, Lee YI. Activation of the insulin-like growth factor II transcription by aflatoxin B1 induced p53 mutant 249 is caused by activation of transcription complexes; implications for a gain-of-function during the formation of hepatocellular carcinoma. Oncogene 2000; 19:3717-26. [PMID: 10949925 DOI: 10.1038/sj.onc.1203694] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Aflatoxin B1 (AFB1) induced mutation of the p53 gene at codon 249 (p53mt249) is critical during the formation of hepatocellular carcinoma (HCC) following hepatitis B virus (HBV) infection. p53mt249 markedly increases insulin-like growth factor II (IGF-II) transcription largely from promoter 4, accumulating the fetal form of IGF-II. Modulation of the transcription factor binding to IGF-II P4 by wild-type p53 and p53mt249 was identified. Wild-type p53 inhibited binding of transcription factors Sp1 and TBP on the P4 promoter, while p53mt249 enhanced the formation of transcriptional complexes through enhanced DNA-protein (Sp1 or TBP) and protein-protein (Sp1 and TBP) interactions. p53mt249 stimulates transcription factor Sp1 phosphorylation which might be a cause of increased transcription factor binding on the P4 promoter while wild-type p53 does not. Transfection of hepatocytes with p53mt249 impaired induction of apoptosis by the HBV-X protein and TNF-alpha. Therefore, the blocking of apoptosis through enhanced production of IGF-II should provide a favorable opportunity for the selection of transformed hepatocytes. These results explain the molecular basis for the genesis of HCC by p53mt249 which was found to be induced by a potent mutagen, AFB1.
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Affiliation(s)
- Y I Lee
- Bioscience Research Division, Korea Research Institute of Bioscience and Biotechnology, Yusong, Taejon
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Park US, Park SK, Lee YI, Park JG, Lee YI. Hepatitis B virus-X protein upregulates the expression of p21waf1/cip1 and prolongs G1-->S transition via a p53-independent pathway in human hepatoma cells. Oncogene 2000; 19:3384-94. [PMID: 10918595 DOI: 10.1038/sj.onc.1203674] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Progression through the cell cycle is controlled by the induction of cyclins and activation of cognate cyclin-dependent kinases. The human hepatitis B virus-X (HBV-X) protein functions in gene expression alterations, in the sensitization of cells to apoptotic killing and deregulates cell growth arrest in certain cancer cell types. We have pursued the mechanism of growth arrest in Hep3B cells, a p53-mutant human hepatocellular carcinoma (HCC) cell line. In stable or transient HBV-X transformed Hep3B cells, HBV-X increased protein and mRNA levels of the cyclin-dependent kinase inhibitor (CDKI) p21(waf1/cip1) increased binding of p21(waf1/cip1) with cyclin-dependent kinase 2 (CDK2), markedly inhibited cyclin E and CDK2 associated phosphorylation of histone H1 and induced the activation of a p21 promoter reporter construct. By using p21 promoter deletion constructs, the HBV-X responsive element was mapped to a region between -1185 and -1482, relative to the transcription start site. Promoter mutation analysis indicated that the HBV-X responsive site coincides with the ets factor binding sites. These data indicate that in human hepatocellular carcinoma cells, HBV-X can circumvent the loss of p53 functions and induces critical downstream regulatory events leading to transcriptional activation of p21(waf1/cip1). As a consequence, there is an increased chance of acquisition of mutations which can enhance the genesis of hepatomas. Our results also emphasize the chemotherapeutic potential of p21(waf1/cip1) inhibitors, particularly in the HBV-X infected hepatoma which lacks functional p53.
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Affiliation(s)
- U S Park
- Bioscience Research Division, Korea Research Institute of Bioscience and Biotechnology, Yusong, Taejon
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Park US, Su JJ, Ban KC, Qin L, Lee EH, Lee YI. Mutations in the p53 tumor suppressor gene in tree shrew hepatocellular carcinoma associated with hepatitis B virus infection and intake of aflatoxin B1. Gene 2000; 251:73-80. [PMID: 10863098 DOI: 10.1016/s0378-1119(00)00183-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Infection with hepadnaviruses and exposure to aflatoxin B1 (AFB1) are considered to be major risk factors in the development of hepatocellular carcinoma (HCC) in humans. A high rate of p53 mutations at codon 249 has been reported in these tumors. The tree shrew (Tupaia belangeri chinensis) is a useful animal model for the development of HCC after human hepatitis B virus (HBV) infection or AFB1 treatment. Therefore, it was of particular interest to determine whether the p53 gene in tree shrew HCCs associated with HBV infection and/or with exposure to AFB1 is affected in the same manner as in human HCCs. We determined the tree shrew p53 wild-type nucleotide sequences by RT-PCR and automatic DNA-sequencing. Tree shrew wild-type p53 sequence showed 91.7 and 93.4% homologies with human p53 nucleotide and amino acids sequences, respectively, while it showed 77.2 and 73.7% homologies in mice. One HCC and normal liver tissue from AFB1 treated and one HCC from AFB1- and HBV-treated tree shrew showed no change in p53 sequences, while three HCCs from AFB1- and HBV-treated tree shrews showed point mutations in p53 sequences. One HCC showed point mutations at codon 275, which is on the DNA-binding domain of p53 gene, which might be a cause of gain-of-function during the development of HCC. As a result, our finding indicates that tree shrews exposed to AFB1 and/or HBV had neither codon 249 mutations nor significant levels of other mutations in the p53 gene, as is the case with humans.
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MESH Headings
- Aflatoxin B1/toxicity
- Amino Acid Sequence
- Animals
- Base Sequence
- Carcinoma, Hepatocellular/chemically induced
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/virology
- Cloning, Molecular
- DNA Mutational Analysis
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Disease Models, Animal
- Genes, Tumor Suppressor/genetics
- Hepatitis B/virology
- Hepatitis B virus
- Liver/metabolism
- Liver/pathology
- Liver Neoplasms/chemically induced
- Liver Neoplasms/genetics
- Liver Neoplasms/virology
- Molecular Sequence Data
- Mutation
- Point Mutation
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Tumor Suppressor Protein p53/genetics
- Tupaiidae/genetics
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Affiliation(s)
- U S Park
- Bioscience Research Division, Korea Research Institute of Bioscience and Biotechnology, Taejon, South Korea
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Abstract
Transforming growth factor-beta1 (TGF-beta) inhibits cell-cycle progression of many types of cells by arresting them in G(1)/S phase through inhibition of the active cyclin-Cdk complexes that lead to inhibition of Rb phosphorylation. In gastric-cancer cells, SNU16, TGF-beta treatment induced enhanced expression of p21(WAF1/CIP1) (p21), which inhibited the kinase activity of cyclin-D- and cyclin-E-associated Cdks and blocked p130 phosphorylation. TGF-beta also enhanced the stability of p130, suggesting that hypophosphorylation of p130 and increased stability of p130 contribute to p130-mediated G(1) arrest in gastric-cancer cells. Our results demonstrate that p21 and p130 are major downstream targets of TGF-beta in gastric-cancer cells and that a p21-G(1) cyclin/Cdks-p130/E2F pathway mediates growth inhibition by TGF-beta in these cells.
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Affiliation(s)
- Y D Yoo
- Laboratory of Experimental Therapeutics and Korea Cancer Center Hospital, Seoul, Republic of Korea.
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Abstract
Cellular immediate early genes (IEG) such as c-fos were originally defined as rapid and transient inducible gene, but their products show a varying degree of basal expression in the brain of normal animals, suggesting that they also play a role in the transcriptional control under physiological conditions. In this study, we used an immunohistochemical method to investigate changes in the number of c-Fos-immunoreactive cells in the cerebral cortex and hippocampal formation of the aged rat. There was a remarkable decrease in the number of c-Fos-immunoreactive cells in the piriform and temporal cortex of aged rats compared with young adult rats. There was a slight decrease in the number of c-Fos-immunoreactive cells in the parietal cortex of aged rat. In the hippocampal complex, there were also decreases in the number of c-Fos-immunoreactive cells in aged rat; the degree of decrease was most prominent in the dentate gyrus. This report provides the first morphological evidence for decreased levels of basal c-Fos expression in some cerebral cortical areas and in the hippocampal complex of aged rats.
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Affiliation(s)
- Y I Lee
- Department of Anatomy, College of Medicine, Seoul National University, Korea
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Lee Y, Park US, Choi I, Yoon SK, Park YM, Lee YI. Human interleukin 6 gene is activated by hepatitis B virus-X protein in human hepatoma cells. Clin Cancer Res 1998; 4:1711-7. [PMID: 9676846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Interleukin 6 (IL-6) is a pleiotropic cytokine that induces many biological activities, including some aspects of the immune reaction and inflammatory responses. In the liver, IL-6 regulates the synthesis of a broad spectrum of acute-phase proteins. IL-6 is also known to be a factor involved in the immunoregulatory perturbations in patients with chronic liver diseases (CLDs). Here, we report that IL-6 can be induced by hepatitis B virus (HBV)-X protein, as evidenced by high levels of serum IL-6 in patients with CLD with HBV infection, IL-6 productions observed in HBV-X-transfected cells, and transcriptional transactivations of the IL-6 gene by HBV-X. We determined serum levels of IL-6 in patients with chronic hepatitis B (CH-B), chronic hepatitis C (CH-C), liver cirrhosis (LC) caused by hepatitis B, and LC with hepatocellular carcinoma (HCC) caused by hepatitis B (LC+HCC). Mean serum levels of IL-6 in all CLD patients were higher than those in normal controls, and the difference was statistically significant (P < 0.05). Mean IL-6 levels of LC and LC+HCC patients were significantly higher than those of CH-B patients (P < 0.05). Because the etiological factor in all cases except CH-C (CH-B, LC, and LC+HCC) was HBV, we checked the possibility of HBV-transactivator-X activation of IL-6 promoter. Using deletion constructs of 5'-flanking regulatory regions of the IL-6 gene linked to the chloramphenicol acetyltransferase gene as a reporter, we found that the binding of nuclear factor-kappaB to a cis element is essential and sufficient for the induction of the IL-6 gene by HBV-X. We also found that HBV-X enhances the binding of two subunits of nuclear factor-kappaB (p65 and p52) to their target DNA binding sequences. These observations are relevant, in that HBV-X might play an important role in hepatic inflammation and diseases by up-regulating IL-6 production, which can eventually lead to LC and HCC.
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Affiliation(s)
- Y Lee
- Molecular Cell Biology Research Division, Korea Research Institute of Bioscience and Biotechnology, KIST, Taejon
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Lee YI, Lee S, Lee Y, Bong YS, Hyun SW, Yoo YD, Kim SJ, Kim YW, Poo HR. The human hepatitis B virus transactivator X gene product regulates Sp1 mediated transcription of an insulin-like growth factor II promoter 4. Oncogene 1998; 16:2367-80. [PMID: 9620554 DOI: 10.1038/sj.onc.1201760] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Human hepatitis B virus (HBV) is one of the causative agents of hepatocellular carcinoma (HCC). The virus encodes a 17 kDa protein, X, which is known to be a causative agent in the formation of HCC. An insulin-like growth factor-II (IGF-II) is expressed during the formation of HCC. Among the four promoters of the IGF-II gene, promoters 2, 3 and 4 become activated during the formation of HCC. The high frequency of detection of hepatitis B virus X (HBV-X) antigen in liver cells from patients with chronic hepatitis, cirrhosis, and liver cancer suggested that the expressions of HBV-X and IGF-II are associated. Studies were carried out to test the relationship between the HBV-X gene product and the activation of IGF-II promoter 4. We demonstrated that the HBV-X protein increases the endogenous IGF-II expression from promoter 3 and 4 of IGF-II gene. Analysis of the fourth promoter of IGF-II gene showed that the HBV-X gene product positively regulates transcription. Two copies of a motif are responsible for conferring HBV-X regulation on the fourth promoter of IGF-II. These motifs have been identified as Sp1 binding sites. Sp1 binding to IGF-II P4 promoter was identified by gel mobility shift assay using purified Sp1. By using a GAL4-Sp1 fusion protein it was demonstrated that HBV-X positively regulates the Spl mediated transcriptional activity of IGF-II in vivo. A protein-affinity chromatography experiment showed that HBV-X protein does not bind directly to Sp1, but HBV-X does augment the DNA binding activity of the phosphorylated form of Sp1 in HepG2 cells. Sp1 was phosphorylated by HBV-X and its DNA-binding activity was up-regulated upon HBV-X transfections. Various HBV-X mutant expression vectors were used for the demonstration of specific interactions between Sp1 and HBV-X. These results indicate that HBV-X functions as a positive regulator of transcription, and that Sp1 is a direct target for the transcriptional regulation of IGF-II. Increasing the DNA binding ability of the phosphorylated form of Sp1 by HBV-X might be an important mechanism for regulating the IGF-II gene expression and possibly promoting cell division during hepatic carcinogenesis. Our experimental results suggest that expression of HBV-X might induce the expression of IGF-II and the IGF-II might play a role in hepatitis B virus pathogenesis during the formation of HCC.
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Affiliation(s)
- Y I Lee
- Molecular Cell Biology Research Division, Korea Research Institute of Bioscience and Biotechnology, Korea Institute of Science and Technology, Taejon
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Bong YS, Cho SH, Nham SU, Lee YI. Cloning and characterization of cDNAs coding for heavy and light chains of agglutinating monoclonal antibody (HAG12islrh) specific for human red blood cells. Biochim Biophys Acta 1998; 1380:156-8. [PMID: 9565676 DOI: 10.1016/s0304-4165(98)00007-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Complementary DNAs encoding the heavy and light chains of the Fab fragment of mouse agglutinating monoclonal antibody against human red blood cells were cloned by polymerase chain reaction and their nucleotide sequences were determined. The sequence analysis showed that the variable regions of the heavy and light chains were the members of mouse heavy-chain subgroup IIa and kappa light-chain subgroup I, respectively. A few unusual amino acids in the constant regions of the heavy chain were also recognized.
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Affiliation(s)
- Y S Bong
- Korea Research Institute of Bioscience and Biotechnology, KIST, Taeduk Science Town, Taejon 305-600, South Korea
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Abstract
PURPOSE The aim of this study was to test whether human cord serum (HCS) containing gonadotropins has an effect on the expansion of oocyte-cumulus complexes (OCCs). METHODS The concentration of follicle stimulating hormone (FSH) and luteinizing hormone (LH) was measured in HCS by radioimmunoassay (RIA). After short-term culture (4 hr) with or without OCCs, medium containing 0.4% bovine serum albumin (BSA) as control or 10% HCS was collected and analyzed for its concentration of estradiol, progesterone, and testosterone. RESULTS The FSH concentration was at the basal level, but the LH level was as high as 142.4 mIU/ml in both natured and denatured serum. Undetectable levels of steroids were observed in control media with or without OCCs. In contrast, a moderate amount of steroid hormones was detected in culture medium containing HCS. OCCs secreted a minute amount of steroid hormones in response to HCS. Similar patterns of cumulus expansion were observable by treatment with HCS, human chorionic gonadotropin (hCG), or HCS plus hCG after 4, 8, or 22 hr of culture. However, no cumulus expansion was observed in controls. CONCLUSION These results suggest that LH in HCS induces cumulus expansion but does not affect the secretion of steroid hormones by OCCs during culture.
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Affiliation(s)
- Y I Lee
- Department of Obstetrics and Gynecology, Chonnam University Medical School, Kwangju, Korea
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Abstract
The imprinted genes, H19 and insulin-like growth factor II (IGF2), have been demonstrated to be necessary for embryonal development in humans. Both genes are reciprocally imprinted, with expression of the maternal H19 and paternal IGF2 alleles, and are normally characterized by monoallelic expression. Recently, loss of imprinting of these genes producing biallelic expression has been observed in childhood tumors including Wilms' tumors (WT), embryonal rhabdomyosarcoma, and adulthood tumors such as lung cancer. To test the existence of loss of imprinting in hepatocellular carcinoma (HCC), we analyzed the status of imprinting of H19 and IGF2 genes in three independent tumors, three HCC and one hepatoblastoma cell lines using AluI and ApaI polymorphisms of these genes, respectively. In contrast to the previous report, all the cases except one tumor and one HCC cell line showed biallelic expression of both H19 and IGF2 genes. Unlike WT, loss of imprinting (LOI) of IGF2 in HCC was not linked to down-regulation of H19 expression, but rather associated with coexpression for H19 and IGF2. Thus, Hl9 and IGF2 expression can be uncoupled in tumors with LOI. The frequent biallelic expression of H19 and IGF2 in hepatocellular carcinoma might play a causal role in the epigenetic mechanism involved in tumor development and/or process.
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Affiliation(s)
- K S Kim
- Molecular and Cell Biology Research Division, Korea Research Institute of Biosciences and Biotechnology, Yoo-Song, Taejon, South Korea
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Abstract
Human Hepatitis B Virus (HBV) replication is accomplished by its own polymerase. The HBV RNase H domain of HBV polymerase has been expressed in Escherichia coli and purified by affinity column chromatography. The MBP-RNase H fusion protein (43 kDa MBP plus 17 kDa HBV RNase H domain) was proved to be RNase H by in vitro activity assay, inhibitor studies, and mutagenesis. The HBV RNase H domain represented the optimal RNase H activity in the presence of either 8 mM MgCl2 or 16 mM MnCl2. In Tris-Cl buffer, the optimum pH for MBP-RNase H fusion protein is between 7.7 and 8.2. The MBP-RNase H fusion protein required 40 mM monovalent cation for its enzyme activity, whereas it showed lower activity at a salt concentration of more than 100 mM. Ribonucleoside Vanadyl complex (RAV) and 2'-deoxyadenosine 5'-monophosphate (dAMP) inhibited the RNase H activity. Moreover, the mutation of highly conserved amino acids in the HBV RNase H domain diminished the RNase H activity. These results clearly suggest that the RNase H activity is separable from viral HBV polymerase enzymatic activities.
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Affiliation(s)
- Y I Lee
- Department of Biology Education, Seoul National University, Korea
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Abstract
Recent studies have explored certain changes with aging of neurons containing neuropeptides. The degree of loss of vasoactive intestinal polypeptide (VIP)-, neuropeptide Y (NPY)- and somatostatin-containing neurons in the aged CNS has not yet been established with certainty however, and available data is often contradictory. Changes with aging of VIP- and NPY-containing neurons were demonstrated by immunocytochemistry in this study. A major loss of VIP-immunoreactive (ir) neurons in aged rat brain was observed in the frontal cortex area 3, parietal cortex area 1, hindlimb area, temporal cortex area 1 and 2, monocular part of occipital cortex area 1, occipital cortex area 2, and retrosplenial cortex. VIP-ir cells in the frontal cortex areas 1 and 2, parietal cortex area 2, forelimb area, binocular part of the occipital cortex area 1, and the dentate gyrus were moderately decreased. The axis of VIP neurons in the aged group showed an irregular orientation tendency, especially in layers II and III. Major loss of NPY-ir neurons in aged rat brain were observed in the retrosplenial cortex, frontal cortex areas 1 and 2, parietal cortex areas 1 and 2, occipital cortex areas 1 and 2, the temporal cortex, hippocampus proper and cingulate cortex. Loss of NPY-ir neurons was observed mostly in layers V and VI. The number and length of dendritic branches also appeared to have decreased and shortened in the aged group. There were only slight decreases of somatostatin-ir cell numbers in the parietal and occipital cortex of the aged group. These results indicate the involvement of VIP and NPY-ir neurons in the aging process of cerebral cortex, and provide the morphological evidence for the decreased number of VIP and NPY neurons by immunocytochemistry in each area of cerebral cortex of aged rats.
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Affiliation(s)
- C I Cha
- Department of Anatomy, College of Medicine, Seoul National University, South Korea
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Abstract
Recent studies have explored certain changes with aging of neurons containing neuropeptides. The extent of loss in aged central nervous system (CNS) of neuronal cells containing neuropeptide Y (NPY) has not yet been established with certainty, and available data is often contradictory. Changes of NPY-containing neurons with aging in the cerebral cortex of aged rat were demonstrated by immunocytochemistry. A major loss of NPY-immunoreactive (ir) neurons in the aged rat brain was observed in the retrosplenial cortex, frontal cortex area 1 and 2, parietal cortex area 1 and 2, occipital cortex area 1 and 2, temporal cortex area 3, cingulate cortex and the hippocampus proper. A loss of NPY-ir neurons was observed mostly in layers V and VI; in addition, the number and length of dendritic branches appeared to be decreased and shortened in the age group. These results indicate the involvement of NPY-ir neurons in the aging process of cerebral cortex, and provide the first morphological evidence for the loss of NPY neurons in the cerebral cortex of aged rats.
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Affiliation(s)
- C I Cha
- Department of Anatomy, College of Medicine, Seoul National University, Chongno-Gu, South Korea
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Kim SO, Park JG, Lee YI. Increased expression of the insulin-like growth factor I (IGF-I) receptor gene in hepatocellular carcinoma cell lines: implications of IGF-I receptor gene activation by hepatitis B virus X gene product. Cancer Res 1996; 56:3831-6. [PMID: 8706031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Hepatitis B virus infection is associated with acute and chronic liver disease and the development of hepatocellular carcinoma (hcc). Several lines of evidence have suggested that hepatitis B virus X protein (HBx), which is a transcriptional trans-activator, plays a role in the process of liver carcinogenesis. We have investigated the expression of insulin-like growth factor I (IGF-I) receptor in human hepatocellular carcinoma cell lines using SNU368 cells containing HBx and SNU387 cells, which lack HBx gene transcript (J-G. Park et al., Int. J. Cancer, 62: 276-282, 1995), in an attempt to understand its possible relationship to the HBx-induced hcc. The binding of 125I-labeled IGF-I to the SNU368 cells was 5-fold higher than that of SNU387 cells. The Scatchard analysis of the binding data revealed a single class binding site for IGF-I with Kd of 7.6 and 8.8 nM and maximum binding capacities of 169 and 33 fmol/10(5) cells, respectively. Therefore, the difference observed in 125I-labeled IGF-I binding between SNU368 and SNU387 cells was due to an increase in the number of IGF-I binding sites with no change in affinity for the IGF-I receptor. An enhanced level of IGF-I receptors in SNU368 cells was also observed by fluorescence-activated cell sorting analysis using a monoclonal antibody against human IGF-I receptor, alpha IR3. The level of IGF-I receptor RNA and the basal IGF-I receptor gene promoter activity in SNU368 cells were 5 and 10 times higher than those observed in SNU387 cells, respectively. To substantiate further that HBx could transactivate the expression of the endogenous IGF-I receptor gene, Hep G2 cells were transiently transfected with a HBx expression vector. The transfection of Hep G2 cells with an HBx expression vector resulted in increased levels of IGF-I receptor RNA, promoter activity, and 125I-labeled IGF-I binding by 2.6-, 2.8-, and 2-fold, respectively. As a result of higher levels of IGF-I receptor, the mitogenic effect of IGFs (IGF-I and IGF-II) on SNU368 cells was 6 times higher than that of SNU387 cells. These results suggest that HBx may play a role in the process of hcc by activating IGF-I receptor gene expression.
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Affiliation(s)
- S O Kim
- Molecular Cell Biology Research Division, Korea Research Institute of Bioscience and Biotechnology, KIST, Yusong, Taejon, Korea
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