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Nahm SS, Lee K, Chun MS, Kang J, Kim S, Jeong SM, Chung JY, Ryu PD. Establishing veterinary graduation competencies and its impact on veterinary medical education in Korea. J Vet Sci 2023; 24:e41. [PMID: 37271509 DOI: 10.4142/jvs.22258] [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] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 03/20/2023] [Accepted: 03/31/2023] [Indexed: 06/06/2023] Open
Abstract
Competencies are defined as an observable and assessable set of knowledge, skills, and attitudes. Graduation competencies, which are more comprehensive, refer to the required abilities of students to perform on-site work immediately after graduation. As graduation competencies set the goal of education, various countries and institutions have introduced them for new veterinary graduates. The Korean Association of Veterinary Medical Colleges has recently established such competencies to standardize veterinary education and enhance quality levels thereof. The purpose of this study is to describe the process of establishing graduation competencies as well as their implication for veterinary education in Korea. Graduation competencies for veterinary education in Korea comprise 5 domains (animal health care and disease management, one health expertise, communication and collaboration, research and learning, and veterinary professionalism). These are further divided into 11 core competencies, and 33 achievement standards, which were carefully chosen from previous case analyses and nation-wide surveys. Currently, graduation competencies are used as a standard for setting clear educational purposes for both instructors and students. Establishing these competencies further initiated the development of detailed learning outcomes, and of a list of basic veterinary clinical performances and skills, which is useful for assessing knowledge and skills. The establishment of graduation competencies is expected to contribute to the continuous development of Korean veterinary education in many ways. These include curriculum standardization and licensing examination reform, which will eventually improve the competencies of new veterinary graduates.
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Affiliation(s)
- Sang-Soep Nahm
- Council on Education, Korean Association of Veterinary Medical Colleges, Seoul 08826, Korea
- Departement of Veterinary Anatomy, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea.
| | - Kichang Lee
- Council on Education, Korean Association of Veterinary Medical Colleges, Seoul 08826, Korea
- Departement of Veterinary Diagnostic Imaging, College of Veterinary Medicine, Jeonbuk National University, Iksan 54596, Korea
| | - Myung Sun Chun
- Council on Education, Korean Association of Veterinary Medical Colleges, Seoul 08826, Korea
- Department of Veterinary Humanities and Social Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Jongil Kang
- Council on Education, Korean Association of Veterinary Medical Colleges, Seoul 08826, Korea
- Choonghyun Animal Hospital, Seoul 06122, Korea
| | - Seungjoon Kim
- Council on Education, Korean Association of Veterinary Medical Colleges, Seoul 08826, Korea
- Department of Veterinary Theriogenology, College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea
| | - Seong Mok Jeong
- Council on Education, Korean Association of Veterinary Medical Colleges, Seoul 08826, Korea
- Department of Veterinary Surgery, College of Veterinary Medicine, Chungnam National University, Daejeon 34134, Korea
| | - Jin Young Chung
- Council on Education, Korean Association of Veterinary Medical Colleges, Seoul 08826, Korea
- Department of Veterinary Internal Medicine, College of Veterinary Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Pan Dong Ryu
- Council on Education, Korean Association of Veterinary Medical Colleges, Seoul 08826, Korea
- Department of Veterinary Humanities and Social Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
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Shen Y, Kim YJ, Ryu PD. Adrenergic Control of Primo Tissue Size in Rats. J Acupunct Meridian Stud 2022; 15:25-36. [DOI: 10.51507/j.jams.2022.15.1.25] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/20/2021] [Accepted: 12/06/2021] [Indexed: 11/03/2022] Open
Affiliation(s)
- Yiming Shen
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Sciences, Seoul National University, Seoul, Korea
| | - Yu Jeong Kim
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Sciences, Seoul National University, Seoul, Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Sciences, Seoul National University, Seoul, Korea
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Han TH, Lee HW, Kang EA, Song MS, Lee SY, Ryu PD. Microglial activation induced by LPS mediates excitation of neurons in the hypothalamic paraventricular nucleus projecting to the rostral ventrolateral medulla. BMB Rep 2021. [PMID: 34814975 PMCID: PMC8728541 DOI: 10.5483/bmbrep.2021.54.12.105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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] [Indexed: 11/22/2022] Open
Abstract
Microglia are known to be activated in the hypothalamic para-ventricular nucleus (PVN) of rats with cardiovascular diseases. However, the exact role of microglial activation in the plasticity of presympathetic PVN neurons associated with the modulation of sympathetic outflow remains poorly investigated. In this study, we analyzed the direct link between microglial activation and spontaneous firing rate along with the underlying synaptic mechanisms in PVN neurons projecting to the rostral ventrolateral medulla (RVLM). Systemic injection of LPS induced microglial activation in the PVN, increased the frequency of spontaneous firing activity of PVN-RVLM neurons, reduced GABAergic inputs into these neurons, and increased plasma NE levels and heart rate. Systemic minocycline injection blocked all the observed LPS-induced effects. Our results indicate that LPS increases the firing rate and decreases GABAergic transmission in PVN-RVLM neurons associated with sympathetic outflow and the alteration is largely attributed to the activation of microglia. Our findings provide some insights into the role of microglial activation in regulating the activity of PVN-RVLM neurons associated with modulation of sympathetic outflow in cardiovascular diseases.
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Affiliation(s)
- Tae Hee Han
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Heow Won Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Eun A Kang
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Min Seok Song
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
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Park KM, Kim SD, Park JB, Hong SJ, Ryu PD. Electrophysiological Properties of Ion Channels in Ascaris suum Tissue Incorporated into Planar Lipid Bilayers. Korean J Parasitol 2021; 59:329-339. [PMID: 34470084 PMCID: PMC8413856 DOI: 10.3347/kjp.2021.59.4.329] [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: 04/09/2021] [Accepted: 07/19/2021] [Indexed: 12/03/2022]
Abstract
Ion channels are important targets of anthelmintic agents. In this study, we identified 3 types of ion channels in Ascaris suum tissue incorporated into planar lipid bilayers using an electrophysiological technique. The most frequent channel was a large-conductance cation channel (209 pS), which accounted for 64.5% of channels incorporated (n=60). Its open-state probability (Po) was ~0.3 in the voltage range of −60~+60 mV. A substate was observed at 55% of the main-state. The permeability ratio of Cl− to K+ (PCl/PK) was ~0.5 and PNa/PK was 0.81 in both states. Another type of cation channel was recorded in 7.5% of channels incorporated (n=7) and discriminated from the large-conductance cation channel by its smaller conductance (55.3 pS). Its Po was low at all voltages tested (~0.1). The third type was an anion channel recorded in 27.9% of channels incorporated (n=26). Its conductance was 39.0 pS and PCl/PK was 8.6±0.8. Po was ~1.0 at all tested potentials. In summary, we identified 2 types of cation and 1 type of anion channels in Ascaris suum. Gating of these channels did not much vary with voltage and their ionic selectivity is rather low. Their molecular nature, functions, and potentials as anthelmintic drug targets remain to be studied further.
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Affiliation(s)
- Kwon Moo Park
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.,Department of Anatomy, School of Medicine, Kyungpook National University, Daegu 41944, Korea
| | - Sun-Don Kim
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.,ChemOn Inc., Yongin 17162, Korea
| | - Jin Bong Park
- Department of Physiology, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Sung-Jong Hong
- Department of Medical Environmental Biology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
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Shin SY, Han TH, Kwon HJ, Kim SJ, Ryu PD. Dexamethasone reduces infectious bursal disease mortality in chickens. J Vet Sci 2021; 22:e33. [PMID: 33908207 PMCID: PMC8170212 DOI: 10.4142/jvs.2021.22.e33] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 09/28/2020] [Revised: 02/07/2021] [Accepted: 02/21/2021] [Indexed: 11/20/2022] Open
Abstract
Very virulent infectious bursal disease virus (vvIBDV) causes high mortality in chickens but measures to reduce the mortality have not been explored. Chickens (8–9 weeks) were treated with 3 agents before and during vvIBDV inoculation. Dexamethasone treatment reduced the mortality of infected chickens (40.7% vs. 3.7%; p < 0.001), but treatment with aspirin or vitamin E plus selenium did not affect the mortality. The bursa of Fabricius appeared to have shrunk in both dead and surviving chickens (p < 0.01). The results indicate that dexamethasone can reduce mortality in vvIBDV-infected chickens and may provide therapeutic clues for saving individual birds infected by the virus.
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Affiliation(s)
- Seung Yub Shin
- Department of Veterinary Pharmacology and Research Center and Research Institute of Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Tae Hee Han
- Department of Veterinary Pharmacology and Research Center and Research Institute of Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Hyuk Joon Kwon
- Farm Animal Clinical Training, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Sun Joong Kim
- Department of Avian Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology and Research Center and Research Institute of Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.
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Abstract
Voltage-gated potassium (Kv) channels are involved in many important cellular functions and play pivotal roles in cancer progression. The expression level of Kv2.1 was observed to be higher in the highly metastatic prostate cancer cells (PC-3), specifically in their membrane, than in immortalized prostate cells (WPMY-1 cells) and comparatively less metastatic prostate cancer cells (LNCaP and DU145 cells). However, Kv2.1 expression was significantly decreased when the cells were treated with anti-oxidants, such as N-acetylcysteine or ascorbic acid, implying that the highly expressed Kv2.1 could detect reactive oxygen species (ROS) in malignant prostate cancer cells. In addition, the blockade of Kv2.1 with stromatoxin-1 or siRNA targeting Kv2.1 significantly inhibited the migration of malignant prostate cancer cells. Our results suggested that Kv2.1 plays an important role as a ROS sensor and that it is a promising therapeutic molecular target in metastasis of prostate cancer.
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Affiliation(s)
- Hyun Woo Park
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Min Seok Song
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Hun Ju Sim
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea
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Lu HJ, Nguyen TL, Hong GS, Pak S, Kim H, Kim H, Kim DY, Kim SY, Shen Y, Ryu PD, Lee MO, Oh U. Tentonin 3/TMEM150C senses blood pressure changes in the aortic arch. J Clin Invest 2021; 130:3671-3683. [PMID: 32484458 DOI: 10.1172/jci133798] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/24/2020] [Indexed: 01/09/2023] Open
Abstract
The baroreceptor reflex is a powerful neural feedback that regulates arterial pressure (AP). Mechanosensitive channels transduce pulsatile AP to electrical signals in baroreceptors. Here we show that tentonin 3 (TTN3/TMEM150C), a cation channel activated by mechanical strokes, is essential for detecting AP changes in the aortic arch. TTN3 was expressed in nerve terminals in the aortic arch and nodose ganglion (NG) neurons. Genetic ablation of Ttn3 induced ambient hypertension, tachycardia, AP fluctuations, and impaired baroreflex sensitivity. Chemogenetic silencing or activation of Ttn3+ neurons in the NG resulted in an increase in AP and heart rate, or vice versa. More important, overexpression of Ttn3 in the NG of Ttn3-/- mice reversed the cardiovascular changes observed in Ttn3-/- mice. We conclude that TTN3 is a molecular component contributing to the sensing of dynamic AP changes in baroreceptors.
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Affiliation(s)
- Huan-Jun Lu
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea.,College of Pharmacy
| | - Thien-Luan Nguyen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea.,College of Pharmacy
| | - Gyu-Sang Hong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Sungmin Pak
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Hyesu Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | - Hyungsup Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
| | | | - Sung-Yon Kim
- Institute of Molecular Biology and Genetics, and
| | - Yiming Shen
- College of Veterinary Medicine, Seoul National University, Seoul, Korea
| | - Pan Dong Ryu
- College of Veterinary Medicine, Seoul National University, Seoul, Korea
| | | | - Uhtaek Oh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Korea
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Lim CJ, Shen Y, Choi MC, Ryu PD. Primo Bundles Identified by Microcomputed Tomography in Primo Vascular Tissue on the Surface of Rat Abdominal Organs. J Acupunct Meridian Stud 2020; 13:136-145. [PMID: 32768624 DOI: 10.1016/j.jams.2020.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 06/22/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The primo vascular system (PVS) is a novel network composed of primo nodes (PNs) and primo vessels (PVs). Currently, its anatomy is not fully understood. OBJECTIVES The aim of this study was to elucidate the three-dimensional PN-PV structure. METHODS Organ-surface PVS tissue was isolated from healthy and anemic rats. The tissues were analyzed by X-ray microcomputed tomography (CT), hematoxylin and eosin staining, and scanning electron microscopy. RESULTS From CT images, we identified one or more bundles in a PV. In the PN, the bundles were enlarged and existed in isolation and/or in anastomosis. The transverse CT images revealed four areas of distinct intensities: zero, low, intermediate, and high. The first two were considered to be the sinuses and the subvessels of the PVS and were identified in the hematoxylin and eosin-stained PN sections. The enlargement of the PN from anemic rats was associated with an increase in the intermediate-intensity area. The high-intensity area demarcated the bundle and was overlapped with the mesothelial cells. In scanning electron microscopy, the PV bundles branched out, tapering down to a single bundle at some distance from the PN. Each bundle was composed of several subvessels (∼5 μm). Clustered round microcells (1-25 μm), scattered flat oval cells (∼15 μm), and amorphous extracellular matrix were observed on the surface of the PVS tissue. CONCLUSIONS The results newly showed that the primo bundle is a structural unit of both PVs and PNs. A bundle was demarcated by high CT intensity and mesothelial cells and consisted of multiple subvessels. The PN bundles contained also sinuses.
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Affiliation(s)
- Chae Jeong Lim
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yiming Shen
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Min Cheol Choi
- Department of Medical Imaging, College of Veterinary Medicine and Research Institute of Veterinary Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
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Ryu PD. 2020 Changes to the Journal of Veterinary Science. J Vet Sci 2020; 21:e28. [PMID: 32017480 PMCID: PMC7000905 DOI: 10.4142/jvs.2020.21.e28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 01/31/2020] [Indexed: 11/20/2022] Open
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Lim CJ, Yoon YS, Ryu PD. Mesothelial Cells Covering the Surface of Primo Vascular System Tissue. J Acupunct Meridian Stud 2019; 13:33-38. [PMID: 31743773 DOI: 10.1016/j.jams.2019.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 10/12/2019] [Revised: 01/08/2020] [Accepted: 01/13/2020] [Indexed: 11/28/2022] Open
Abstract
The primo vascular system (PVS) is reported to have a periductium composed of cells with spherical or spindle-shaped nuclei and abundant cytoplasm. However, little is known about these periductium cells. In this study, we examined the morphological features of cells covering the PVS tissue isolated from the surface of abdominal organs of rats. By hematoxylin and eosin (H&E) staining, we observed a layer of dark nuclei on the basement membrane at the borders of the sections of primo node (PN), primo vessel (PV), and their subunits. The nuclei appeared thin and linear (10-14 μm), elliptical (8-10 × 3-4 μm), and round (5-7 μm). The borders of the PVS tissue sections were immunostained with a selective antibody for mesothelial cells (MCs). Areas of immunoreactivity overlapped with the flattened cells are shown by hematoxylin and eosin staining. By scanning electron microscopy, we further identified elliptical (11 × 21 μm) and rectangular squamous MCs (length, 10 μm). There were numerous stomata (∼200 nm) and microparticles (20-200 nm) on the surface of the PVS MCs. In conclusion, this study presents the novel finding that the PVS periductium is composed of squamous MCs. These cells tightly line the luminal surface of the PVS tissue, including PNs, PVs, and small branches of the PVs in the abdominal cavity. These results will help us to understand the physiological roles such as hyaluronan secretion and the fine structure of PVS tissue.
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Affiliation(s)
- Chae Jeong Lim
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yeo Sung Yoon
- Department of Anatomy & Cell Biology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Republic of Korea.
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Shen Y, Park JB, Lee SY, Han SK, Ryu PD. Exercise training normalizes elevated firing rate of hypothalamic presympathetic neurons in heart failure rats. Am J Physiol Regul Integr Comp Physiol 2018; 316:R110-R120. [PMID: 30485115 DOI: 10.1152/ajpregu.00225.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 02/02/2023]
Abstract
Exercise training (ExT) normalizes elevated sympathetic nerve activity in heart failure (HF), but the underlying mechanisms are not well understood. In this study, we examined the effects of 3 wk of ExT on the electrical activity of the hypothalamic presympathetic neurons in the brain slice of HF rats. HF rats were prepared by ligating the left descending coronary artery. The electrophysiological properties of paraventricular nucleus neurons projecting to the rostral ventrolateral medulla (PVN-RVLM) were examined using the slice patch-clamp technique. The neuronal firing rate was elevated in HF rats, and ExT induced a reduction in the firing rate ( P < 0.01). This ExT-induced decrease in the firing rate was associated with an increased frequency of spontaneous and miniature inhibitory postsynaptic current (IPSCs; P < 0.05). There was no significant change in excitatory postsynaptic current. Replacing Ca2+ with Mg2+ in the recording solution reduced the elevated IPSC frequency in HF rats with ExT ( P < 0.01) but not in those without ExT, indicating an increase in the probability of GABA release. In contrast, ExT did not restore the reduced GABAA receptor-mediated tonic inhibitory current in HF rats. A GABAA receptor blocker (bicuculline, 20 μM) increased the firing rate in HF rats with ExT ( P < 0.01) but not in those without ExT. Collectively, these results show that ExT normalized the elevated firing activity by increasing synaptic GABA release in PVN-RVLM neurons in HF rats. Our findings provide a brain mechanism underlying the beneficial effects of ExT in HF, which may shed light on the pathophysiology of other diseases accompanied by sympathetic hyperactivation.
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Affiliation(s)
- Yiming Shen
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul , Republic of Korea
| | - Jin Bong Park
- Department of Physiology, School of Medicine, Chungnam National University , Daejeon , Republic of Korea
| | - So Yeong Lee
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul , Republic of Korea
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Republic of Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul , Republic of Korea
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Shen Y, Han SK, Ryu PD. Comparison of electrophysiological properties of two types of pre-sympathetic neurons intermingled in the hypothalamic paraventricular nucleus. J Vet Sci 2018; 19:483-491. [PMID: 29649859 PMCID: PMC6070595 DOI: 10.4142/jvs.2018.19.4.483] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [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: 01/24/2018] [Revised: 03/06/2018] [Accepted: 03/09/2018] [Indexed: 11/20/2022] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) contains two types of neurons projecting to either the rostral ventrolateral medulla (PVNRVLM) or the intermediolateral horn (IML) of the spinal cord (PVNIML). These two neuron groups are intermingled in the same subdivisions of the PVN and differentially regulate sympathetic outflow. However, electrophysiological evidence supporting such functional differences is largely lacking. Herein, we compared the electrophysiological properties of these neurons by using patch-clamp and retrograde-tracing techniques. Most neurons (>70%) in both groups spontaneously fired in the cell-attached mode. When compared to the PVNIML neurons, the PVNRVLM neurons had a lower firing rate and a more irregular firing pattern (p < 0.05). The PVNRVLM neurons showed smaller resting membrane potential, slower rise and decay times, and greater duration of spontaneous action potentials (p < 0.05). The PVNRVLM neurons received greater inhibitory synaptic inputs (frequency, p < 0.05) with a shorter rise time (p < 0.05). Taken together, the results indicate that the two pre-sympathetic neurons differ in their intrinsic and extrinsic electrophysiological properties, which may explain the lower firing activity of the PVNRVLM neurons. The greater inhibitory synaptic inputs to the PVNRVLM neurons also imply that these neurons have more integrative roles in regulation of sympathetic activity.
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Affiliation(s)
- Yiming Shen
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Science, Seoul National University, Seoul 08826, Korea
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju 54896, Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Science, Seoul National University, Seoul 08826, Korea
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Song MS, Park SM, Park JS, Byun JH, Jin HJ, Seo SH, Ryu PD, Lee SY. Kv3.1 and Kv3.4, Are Involved in Cancer Cell Migration and Invasion. Int J Mol Sci 2018; 19:ijms19041061. [PMID: 29614836 PMCID: PMC5979479 DOI: 10.3390/ijms19041061] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/13/2018] [Accepted: 03/31/2018] [Indexed: 12/27/2022] Open
Abstract
Voltage-gated potassium (Kv) channels, including Kv3.1 and Kv3.4, are known as oxygen sensors, and their function in hypoxia has been well investigated. However, the relationship between Kv channels and tumor hypoxia has yet to be investigated. This study demonstrates that Kv3.1 and Kv3.4 are tumor hypoxia-related Kv channels involved in cancer cell migration and invasion. Kv3.1 and Kv3.4 protein expression in A549 and MDA-MB-231 cells increased in a cell density-dependent manner, and the pattern was similar to the expression patterns of hypoxia-inducible factor-1α (HIF-1α) and reactive oxygen species (ROS) according to cell density, whereas Kv3.3 protein expression did not change in A549 cells with an increase in cell density. The Kv3.1 and Kv3.4 blocker blood depressing substance (BDS) did not affect cell proliferation; instead, BDS inhibited cell migration and invasion. We found that BDS inhibited intracellular pH regulation and extracellular signal-regulated kinase (ERK) activation in A549 cells cultured at a high density, potentially resulting in BDS-induced inhibition of cell migration and invasion. Our data suggest that Kv3.1 and Kv3.4 might be new therapeutic targets for cancer metastasis.
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Affiliation(s)
- Min Seok Song
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - Su Min Park
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - Jeong Seok Park
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - Jin Ho Byun
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - Hee Jung Jin
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - Seung Hyun Seo
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, Korea.
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Choi SY, Ryu PD, Joo SW, Lee SY. Alteration of MicroRNA Expression Profiles by Surface-Modified Gold Nanoparticles in Human Lung Adenocarcinoma Cells. J Nanosci Nanotechnol 2018; 18:3024-3030. [PMID: 29442990 DOI: 10.1166/jnn.2018.14395] [Citation(s) in RCA: 2] [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] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
MicroRNAs that bind to mRNA are important post-transcriptional regulators that control gene expression by degradation or suppressing translation of target mRNAs. Several studies indicate that nanoparticles (NPs) induce alterations in microRNA expression relating to cell processes including cell development and progressive diseases. However, the alteration of microRNA expression by surface-modified gold nanoparticles (AuNPs) in A549 cells has not been reported. In order to investigate the patterns of microRNA expression, we analyzed data from microRNA arrays using cells treated with citrate- or chitosan-AuNPs. The results demonstrate that the expression of microRNA (hsa-miR-198) in cells treated with citrate-AuNPs significantly differed from non-treated cells, and the expression of 16 microRNAs in cells treated with chitosan-AuNPs significantly differed from non-treated cells. Furthermore, the predicted target genes of microRNAs were related to proliferation, apoptosis, migration, and cell differentiation, including the mitogen-activated protein kinase, ErbB, and Wnt signaling pathway. Thus, the alteration of microRNA expression profiles by citrate- and chitosan-AuNPs would mediate the regulation of the cell processes including cell survival, migration, and differentiation.
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Affiliation(s)
- Seon Young Choi
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Sang-Woo Joo
- Department of Chemistry, Soongsil University, Seoul, 06978, Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
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15
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Shen Y, Bhattarai JP, Park SJ, Lee GS, Ryu PD, Han SK. Korean red ginseng excitation of paraventricular nucleus neurons via non-N-methyl-D-aspartate glutamate receptor activation in mice. J Vet Sci 2018; 19:172-178. [PMID: 29169227 PMCID: PMC5879065 DOI: 10.4142/jvs.2018.19.2.172] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/23/2017] [Accepted: 10/26/2017] [Indexed: 11/20/2022] Open
Abstract
It has been reported that Korean red ginseng (KRG), a valuable and important traditional medicine, has varied effects on the central nervous system, suggesting its activities are complicated. The paraventricular nucleus (PVN) neurons of the hypothalamus has a critical role in stress responses and hormone secretions. Although the action mechanisms of KRG on various cells and systems have been reported, the direct membrane effects of KRG on PVN neurons have not been fully described. In this study, the direct membrane effects of KRG on PVN neuronal activity were investigated by using a perforated patch-clamp in ICR mice. In gramicidin perforated patch-clamp mode, KRG extract (KRGE) induced repeatable depolarization followed by hyperpolarization of PVN neurons. The KRGE-induced responses were concentration- dependent and persisted in the presence of tetrodotoxin, a voltage sensitive Na+ channel blocker. The KRGE-induced responses were suppressed by 6-cyano-7-nitroquinoxaline-2,3-dione (10 μM), a non-N-methyl-D-aspartate (NMDA) glutamate receptor antagonist, but not by picrotoxin, a type A gamma-aminobutyric acid receptor antagonist. The results indicate that KRG activates non-NMDA glutamate receptors of PVN neurons in mice, suggesting that KRG may be a candidate for use in regulation of stress responses by controlling autonomic nervous system and hormone secretion.
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Affiliation(s)
- Yiming Shen
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju 54896, Korea
- Department of Pharmacology, School of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Janardhan P Bhattarai
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju 54896, Korea
| | - Soo Joung Park
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju 54896, Korea
| | - Gyu Seung Lee
- Daejeon Dong-gu Health Promotion Center, Daejeon 34691, Korea
| | - Pan Dong Ryu
- Department of Pharmacology, School of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju 54896, Korea
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16
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Cho YS, Lee MH, Kim JM, Lee HS, Yoo HS, Park YH, Ryu PD. Immunological responses against vancomycin-resistant Enterococcus faecium and Enterococcus faecalis by mice. J Immunoassay Immunochem 2018; 39:163-172. [PMID: 29308974 DOI: 10.1080/15321819.2017.1407943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 01/11/2023]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) infections in humans can currently only be treated with vancomycin. Consequently, vancomycin-resistant Enterococcus spp. pose a serious public health hazard because MRSA can acquire their vancomycin resistance. While the microbiological and genetic characteristics of vancomycin-resistant enterococci (VRE) have been extensively studied, serological diagnostic tools for these organisms are lacking. The VanA and VanB classes of VRE show marked resistance. Here, we identified the VanA and VanB proteins that are immunogenic in mice. To do so, mice were orally infected with a VanA strain of E. faecium or a VanB strain of E. faecalis and the serologically immunogenic proteins were identified by SDS-PAGE and Western blot analysis. The mice reacted to the 27 and 65 kDa cell envelope (CE) proteins of VanA at 1 week post-infection (wpi) and then reacted to the 100 kDa cytoplasmic protein (CP) at 2-4 wpi. With regard to VanB, the mice responded at 1-4 wpi, 3-4 wpi, and 4 wpi to the 70 kDa, 25 and 35 kDa, and 79 kDa CE proteins, respectively, and at 3 wpi to the 39 kDa CP. The identification of these immunogenic proteins may be useful for diagnosing and for producing immunotherapeutic VRE antibodies.
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Affiliation(s)
- Yun Sang Cho
- a Bacterial Disease Division, Animal and Plant Disease Research Department , Animal and Plant Quarantine Agency , Gimcheon , Gyeongsangbuk-do , Republic of Korea
| | - Mun Han Lee
- b Laboratory of Veterinary Biochemistry, College of Veterinary Medicine , Seoul National University , Seoul , Republic of Korea
| | - Jong Man Kim
- a Bacterial Disease Division, Animal and Plant Disease Research Department , Animal and Plant Quarantine Agency , Gimcheon , Gyeongsangbuk-do , Republic of Korea
| | - Hee Soo Lee
- a Bacterial Disease Division, Animal and Plant Disease Research Department , Animal and Plant Quarantine Agency , Gimcheon , Gyeongsangbuk-do , Republic of Korea
| | - Han Sang Yoo
- c Laboratory of Veterinary Infectious Diseases, College of Veterinary Medicine , Seoul National University , Seoul , Republic of Korea
| | - Yong Ho Park
- d Laboratory of Veterinary Microbiology, College of Veterinary Medicine , Seoul National University , Seoul , Republic of Korea
| | - Pan Dong Ryu
- e Laboratory of Veterinary Pharmacology, College of Veterinary Medicine , Seoul National University , Seoul , Republic of Korea
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Song MS, Ryu PD, Lee SY. Kv3.4 is modulated by HIF-1α to protect SH-SY5Y cells against oxidative stress-induced neural cell death. Sci Rep 2017; 7:2075. [PMID: 28522852 PMCID: PMC5437029 DOI: 10.1038/s41598-017-02129-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 04/06/2017] [Indexed: 12/14/2022] Open
Abstract
The Kv3.4 channel is characterized by fast inactivation and sensitivity to oxidation. However, the physiological role of Kv3.4 as an oxidation-sensitive channel has yet to be investigated. Here, we demonstrate that Kv3.4 plays a pivotal role in oxidative stress-related neural cell damage as an oxidation-sensitive channel and that HIF-1α down-regulates Kv3.4 function, providing neuroprotection. MPP+ and CoCl2 are reactive oxygen species (ROS)-generating reagents that induce oxidative stress. However, only CoCl2 decreases the expression and function of Kv3.4. HIF-1α, which accumulates in response to CoCl2 treatment, is a key factor in Kv3.4 regulation. In particular, mitochondrial Kv3.4 was more sensitive to CoCl2. Blocking Kv3.4 function using BDS-II, a Kv3.4-specific inhibitor, protected SH-SY5Y cells against MPP+-induced neural cell death. Kv3.4 inhibition blocked MPP+-induced cytochrome c release from the mitochondrial intermembrane space to the cytosol and mitochondrial membrane potential depolarization, which are characteristic features of apoptosis. Our results highlight Kv3.4 as a possible new therapeutic paradigm for oxidative stress-related diseases, including Parkinson’s disease.
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Affiliation(s)
- Min Seok Song
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea.
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18
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Choi SY, Kim HR, Ryu PD, Lee SY. Regulation of voltage-gated potassium channels attenuates resistance of side-population cells to gefitinib in the human lung cancer cell line NCI-H460. BMC Pharmacol Toxicol 2017. [DOI: 10.1186/s40360-017-0118-9 order by 25532--] [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: 11/10/2022] Open
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Choi SY, Kim HR, Ryu PD, Lee SY. Regulation of voltage-gated potassium channels attenuates resistance of side-population cells to gefitinib in the human lung cancer cell line NCI-H460. BMC Pharmacol Toxicol 2017; 18:14. [PMID: 28219421 PMCID: PMC5319158 DOI: 10.1186/s40360-017-0118-9] [Citation(s) in RCA: 9] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 01/28/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Side-population (SP) cells that exclude anti-cancer drugs have been found in various tumor cell lines. Moreover, SP cells have a higher proliferative potential and drug resistance than main population cells (Non-SP cells). Also, several ion channels are responsible for the drug resistance and proliferation of SP cells in cancer. METHODS To confirm the expression and function of voltage-gated potassium (Kv) channels of SP cells, these cells, as well as highly expressed ATP-binding cassette (ABC) transporters and stemness genes, were isolated from a gefitinib-resistant human lung adenocarcinoma cell line (NCI-H460), using Hoechst 33342 efflux. RESULTS In the present study, we found that mRNA expression of Kv channels in SP cells was different compared to Non-SP cells, and the resistance of SP cells to gefitinib was weakened with a combination treatment of gefitinib and Kv channel blockers or a Kv7 opener, compared to single-treatment gefitinib, through inhibition of the Ras-Raf signaling pathway. CONCLUSIONS The findings indicate that Kv channels in SP cells could be new targets for reducing the resistance to gefitinib.
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Affiliation(s)
- Seon Young Choi
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Hang-Rae Kim
- Department of Anatomy and Cell Biology, and Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea.
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20
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Choi SY, Kim HR, Ryu PD, Lee SY. Regulation of voltage-gated potassium channels attenuates resistance of side-population cells to gefitinib in the human lung cancer cell line NCI-H460. BMC Pharmacol Toxicol 2017. [DOI: 10.1186/s40360-017-0118-9 order by 21742--] [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: 11/10/2022] Open
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21
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Affiliation(s)
- Han Sang Yoo
- College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Pan Dong Ryu
- College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
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Lee JH, Park JW, Byun JK, Kim HK, Ryu PD, Lee SY, Kim DY. Silencing of voltage-gated potassium channel KV9.3 inhibits proliferation in human colon and lung carcinoma cells. Oncotarget 2016; 6:8132-43. [PMID: 25924237 PMCID: PMC4480740 DOI: 10.18632/oncotarget.3517] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 12/09/2014] [Accepted: 02/03/2015] [Indexed: 01/12/2023] Open
Abstract
Voltage-gated potassium (Kv) channels are known to be involved in cancer development and cancer cell proliferation. KV9.3, an electronically silent subunit, forms heterotetramers with KV2.1 in excitable cells and modulates its electrophysiological properties. However, the role of KV9.3 alone in non-excitable cancer cells has not been studied. Here, we evaluated the effect of silencing KV9.3 on cancer cell proliferation in HCT15 colon carcinoma cells and A549 lung adenocarcinoma cells. We confirmed the expression of KV9.3 mRNA in HCT15 and A549 cells and showed that silencing KV9.3 using small interfering RNA caused G0/G1 cell cycle arrest and alterations in cell cycle regulatory proteins in both HCT15 and A549 cells without affecting apoptosis. Also, stable knockdown of KV9.3 expression using short-hairpin RNA inhibited tumor growth in SCID mouse xenograft model. Using a bioinformatics approach, we identified Sp1 binding sites in the promoter region of the gene encoding KV9.3. We further found that Sp1 bound to this region and showed that the Sp1 inhibitor, mithramycin A, induced a concentration-dependent decrease in KV9.3 expression. Taken together, these data suggest that knockdown of KV9.3 inhibits proliferation in colon carcinoma and lung adenocarcinoma cell lines and may be regulated by Sp1.
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Affiliation(s)
- Jeong-Ha Lee
- Laboratory of Veterinary Pathology, Seoul National University, Seoul, Korea
| | - Jun-Won Park
- Biomolecular Function Research Branch, National Cancer Center, Goyang, Gyeonggi, Korea
| | - Jun Kyu Byun
- Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Hark Kyun Kim
- Biomolecular Function Research Branch, National Cancer Center, Goyang, Gyeonggi, Korea
| | - Pan Dong Ryu
- Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - So Yeong Lee
- Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Dae-Yong Kim
- Laboratory of Veterinary Pathology, Seoul National University, Seoul, Korea
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23
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Yang JE, Song MS, Shen Y, Ryu PD, Lee SY. The Role of KV7.3 in Regulating Osteoblast Maturation and Mineralization. Int J Mol Sci 2016; 17:407. [PMID: 26999128 PMCID: PMC4813262 DOI: 10.3390/ijms17030407] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/02/2016] [Accepted: 03/10/2016] [Indexed: 11/19/2022] Open
Abstract
KCNQ (KV7) channels are voltage-gated potassium (KV) channels, and the function of KV7 channels in muscles, neurons, and sensory cells is well established. We confirmed that overall blockade of KV channels with tetraethylammonium augmented the mineralization of bone-marrow-derived human mesenchymal stem cells during osteogenic differentiation, and we determined that KV7.3 was expressed in MG-63 and Saos-2 cells at the mRNA and protein levels. In addition, functional KV7 currents were detected in MG-63 cells. Inhibition of KV7.3 by linopirdine or XE991 increased the matrix mineralization during osteoblast differentiation. This was confirmed by alkaline phosphatase, osteocalcin, and osterix in MG-63 cells, whereas the expression of Runx2 showed no significant change. The extracellular glutamate secreted by osteoblasts was also measured to investigate its effect on MG-63 osteoblast differentiation. Blockade of KV7.3 promoted the release of glutamate via the phosphorylation of extracellular signal-regulated kinase 1/2-mediated upregulation of synapsin, and induced the deposition of type 1 collagen. However, activation of KV7.3 by flupirtine did not produce notable changes in matrix mineralization during osteoblast differentiation. These results suggest that KV7.3 could be a novel regulator in osteoblast differentiation.
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Affiliation(s)
- Ji Eun Yang
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| | - Min Seok Song
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| | - Yiming Shen
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
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Choi SY, Song MS, Ryu PD, Lam ATN, Joo SW, Lee SY. Gold nanoparticles promote osteogenic differentiation in human adipose-derived mesenchymal stem cells through the Wnt/β-catenin signaling pathway. Int J Nanomedicine 2015; 10:4383-92. [PMID: 26185441 PMCID: PMC4500612 DOI: 10.2147/ijn.s78775] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Gold nanoparticles (AuNPs) are attractive materials for use in biomedicine due to their physical properties. Increasing evidence suggests that several nanoparticles induce the differentiation of human mesenchymal stem cells into osteoblasts and adipocytes. In this study, we hypothesized that chitosan-conjugated AuNPs promote the osteogenic differentiation of human adipose-derived mesenchymal stem cells. For the evaluation of osteogenic differentiation, alizarin red staining, an alamarBlue(®) assay, and a quantitative real-time polymerase chain reaction analysis were performed. In order to examine specific signaling pathways, immunofluorescence and a western blotting assay were performed. Our results demonstrate that chitosan-conjugated AuNPs increase the deposition of calcium content and the expression of marker genes related to osteogenic differentiation in human adipose-derived mesenchymal stem cells at nontoxic concentrations. These results indicate that chitosan-conjugated AuNPs promote osteogenesis through the Wnt/β-catenin signaling pathway. Therefore, chitosan-conjugated AuNPs can be used as a reagent for promoting bone formation.
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Affiliation(s)
- Seon Young Choi
- Laboratory of Veterinary Pharmacology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, South Korea
| | - Min Seok Song
- Laboratory of Veterinary Pharmacology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, South Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, South Korea
| | - Anh Thu Ngoc Lam
- Department of Chemistry, Soongsil University, Seoul, South Korea
| | - Sang-Woo Joo
- Department of Chemistry, Soongsil University, Seoul, South Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, South Korea
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Pandit S, Jo JY, Lee SU, Lee YJ, Lee SY, Ryu PD, Lee JU, Kim HW, Jeon BH, Park JB. Enhanced astroglial GABA uptake attenuates tonic GABAA inhibition of the presympathetic hypothalamic paraventricular nucleus neurons in heart failure. J Neurophysiol 2015; 114:914-26. [PMID: 26063771 DOI: 10.1152/jn.00080.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 01/27/2015] [Accepted: 06/03/2015] [Indexed: 01/08/2023] Open
Abstract
γ-Aminobutyric acid (GABA) generates persistent tonic inhibitory currents (Itonic) and conventional inhibitory postsynaptic currents in the hypothalamic paraventricular nucleus (PVN) via activation of GABAA receptors (GABAARs). We investigated the pathophysiological significance of astroglial GABA uptake in the regulation of Itonic in the PVN neurons projecting to the rostral ventrolateral medulla (PVN-RVLM). The Itonic of PVN-RVLM neurons were significantly reduced in heart failure (HF) compared with sham-operated (SHAM) rats. Reduced Itonic sensitivity to THIP argued for the decreased function of GABAAR δ subunits in HF, whereas similar Itonic sensitivity to benzodiazepines argued against the difference of γ2 subunit-containing GABAARs in SHAM and HF rats. HF Itonic attenuation was reversed by a nonselective GABA transporter (GAT) blocker (nipecotic acid, NPA) and a GAT-3 selective blocker, but not by a GAT-1 blocker, suggesting that astroglial GABA clearance increased in HF. Similar and minimal Itonic responses to bestrophin-1 blockade in SHAM and HF neurons further argued against a role for astroglial GABA release in HF Itonic attenuation. Finally, the NPA-induced inhibition of spontaneous firing was greater in HF than in SHAM PVN-RVLM neurons, whereas diazepam induced less inhibition of spontaneous firing in HF than in SHAM neurons. Overall, our results showed that combined with reduced GABAARs function, the enhanced astroglial GABA uptake-induced attenuation of Itonic in HF PVN-RVLM neurons explains the deficit in tonic GABAergic inhibition and increased sympathetic outflow from the PVN during heart failure.
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Affiliation(s)
- Sudip Pandit
- Department of Physiology, School of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Ji Yoon Jo
- Department of Physiology, School of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Sang Ung Lee
- Department of Anesthesiology and Pain Medicine, Brain Research Institute, School of Medicine, Chungnam National University, Daejeon, Republic of Korea; and
| | - Young Jae Lee
- Department of Anesthesiology and Pain Medicine, Brain Research Institute, School of Medicine, Chungnam National University, Daejeon, Republic of Korea; and
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Science, Seoul National University, Seoul, Republic of Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute of Veterinary Science, Seoul National University, Seoul, Republic of Korea
| | - Jung Un Lee
- Department of Anesthesiology and Pain Medicine, Brain Research Institute, School of Medicine, Chungnam National University, Daejeon, Republic of Korea; and
| | - Hyun-Woo Kim
- Department of Physiology, School of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Byeong Hwa Jeon
- Department of Physiology, School of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Jin Bong Park
- Department of Physiology, School of Medicine, Chungnam National University, Daejeon, Republic of Korea;
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Jang SH, Byun JK, Jeon WI, Choi SY, Park J, Lee BH, Yang JE, Park JB, O'Grady SM, Kim DY, Ryu PD, Joo SW, Lee SY. Nuclear localization and functional characteristics of voltage-gated potassium channel Kv1.3. J Biol Chem 2015; 290:12547-57. [PMID: 25829491 PMCID: PMC4432276 DOI: 10.1074/jbc.m114.561324] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/26/2015] [Indexed: 12/29/2022] Open
Abstract
It is widely known that ion channels are expressed in the plasma membrane. However, a few studies have suggested that several ion channels including voltage-gated K(+) (Kv) channels also exist in intracellular organelles where they are involved in the biochemical events associated with cell signaling. In the present study, Western blot analysis using fractionated protein clearly indicates that Kv1.3 channels are expressed in the nuclei of MCF7, A549, and SNU-484 cancer cells and human brain tissues. In addition, Kv1.3 is located in the plasma membrane and the nucleus of Jurkat T cells. Nuclear membrane hyperpolarization after treatment with margatoxin (MgTX), a specific blocker of Kv1.3 channels, provides evidence for functional channels at the nuclear membrane of A549 cells. MgTX-induced hyperpolarization is abolished in the nuclei of Kv1.3 silenced cells, and the effects of MgTX are dependent on the magnitude of the K(+) gradient across the nuclear membrane. Selective Kv1.3 blockers induce the phosphorylation of cAMP response element-binding protein (CREB) and c-Fos activation. Moreover, Kv1.3 is shown to form a complex with the upstream binding factor 1 in the nucleus. Chromatin immunoprecipitation assay reveals that Sp1 transcription factor is directly bound to the promoter region of the Kv1.3 gene, and the Sp1 regulates Kv1.3 expression in the nucleus of A549 cells. These results demonstrate that Kv1.3 channels are primarily localized in the nucleus of several types of cancer cells and human brain tissues where they are capable of regulating nuclear membrane potential and activation of transcription factors, such as phosphorylated CREB and c-Fos.
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Affiliation(s)
- Soo Hwa Jang
- From the Laboratories of Veterinary Pharmacology and the Biomedical Research Center, School of Biological Sciences, University of Ulsan, Ulsan 680-749, Korea
| | - Jun Kyu Byun
- From the Laboratories of Veterinary Pharmacology and
| | - Won-Il Jeon
- From the Laboratories of Veterinary Pharmacology and
| | | | - Jin Park
- the Department of Chemistry, Soongsil University, Seoul 156-743, Korea
| | - Bo Hyung Lee
- From the Laboratories of Veterinary Pharmacology and
| | - Ji Eun Yang
- From the Laboratories of Veterinary Pharmacology and
| | - Jin Bong Park
- the Department of Physiology, School of Medicine, Chungnam National University, Daejeon 305-764, Korea, and
| | - Scott M O'Grady
- the Department of Animal Science and Integrative Biology and Physiology, University of Minnesota, St. Paul, Minnesota 55455
| | - Dae-Yong Kim
- Veterinary Pathology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea
| | - Pan Dong Ryu
- From the Laboratories of Veterinary Pharmacology and
| | - Sang-Woo Joo
- the Department of Chemistry, Soongsil University, Seoul 156-743, Korea
| | - So Yeong Lee
- From the Laboratories of Veterinary Pharmacology and
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Song MS, Ryu PD, Lee SY. Neuroprotective Effect of Sea Anemone Polypeptide BDS‐II Toxin: Relationship between Neurodegenerative Disease and Kv3.4. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.845.15] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Min Seok Song
- Veterinary MedicineSeoul National UniversitySeoulKorea
| | - Pan Dong Ryu
- Veterinary MedicineSeoul National UniversitySeoulKorea
| | - So Yeong Lee
- Veterinary MedicineSeoul National UniversitySeoulKorea
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Affiliation(s)
- Ji Eun Yang
- College of Veterinary Medicine Seoul National UniversityRepublic of Korea
| | - Min Seok Song
- College of Veterinary Medicine Seoul National UniversityRepublic of Korea
| | - Pan Dong Ryu
- College of Veterinary Medicine Seoul National UniversityRepublic of Korea
| | - So Yeong Lee
- College of Veterinary Medicine Seoul National UniversityRepublic of Korea
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29
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Shen YM, Lee SY, Han SK, Ryu PD. Electrophysiological Properties of Magno‐and Parvo‐Cellular Neurons in Rat Hypothalamic Paraventricular Nucleus. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.lb727] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yi Ming Shen
- Veterinary Pharmacology Seoul National UniversityKorea
| | - So Yeong Lee
- Veterinary Pharmacology Seoul National UniversityKorea
| | | | - Pan Dong Ryu
- Veterinary Pharmacology Seoul National UniversityKorea
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Chong W, Kim SN, Han SK, Lee SY, Ryu PD. Low Non-NMDA Receptor Current Density as Possible Protection Mechanism from Neurotoxicity of Circulating Glutamate on Subfornical Organ Neurons in Rats. Korean J Physiol Pharmacol 2015; 19:177-81. [PMID: 25729280 PMCID: PMC4342738 DOI: 10.4196/kjpp.2015.19.2.177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 12/31/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 11/17/2022]
Abstract
The subfornical organ (SFO) is one of circumventricular organs characterized by the lack of a normal blood brain barrier. The SFO neurons are exposed to circulating glutamate (60~100 µM), which may cause excitotoxicity in the central nervous system. However, it remains unclear how SFO neurons are protected from excitotoxicity caused by circulating glutamate. In this study, we compared the glutamate-induced whole cell currents in SFO neurons to those in hippocampal CA1 neurons using the patch clamp technique in brain slice. Glutamate (100 µM) induced an inward current in both SFO and hippocampal CA1 neurons. The density of glutamate-induced current in SFO neurons was significantly smaller than that in hippocampal CA1 neurons (0.55 vs. 2.07 pA/pF, p<0.05). To further identify the subtype of the glutamate receptors involved, the whole cell currents induced by selective agonists were then compared. The current densities induced by AMPA (0.45 pA/pF) and kainate (0.83 pA/pF), non-NMDA glutamate receptor agonists in SFO neurons were also smaller than those in hippocampal CA1 neurons (2.44 pA/pF for AMPA, p<0.05; 2.34 pA/pF for kainate, p< 0.05). However, the current density by NMDA in SFO neurons was not significantly different from that of hippocampal CA1 neurons (1.58 vs. 1.47 pA/pF, p>0.05). These results demonstrate that glutamate-mediated action through non-NMDA glutamate receptors in SFO neurons is smaller than that of hippocampal CA1 neurons, suggesting a possible protection mechanism from excitotoxicity by circulating glutamate in SFO neurons.
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Affiliation(s)
- Wonee Chong
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea
| | - Seong Nam Kim
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju 561-756, Korea
| | - So Yeong Lee
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea
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31
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Song MS, Choi SY, Ryu PD, Lee SY. Voltage‐gated K
+
channel, Kv3.3 is involved in hemin‐induced K562 differentiation (893.13). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.893.13] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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32
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Lee SK, Ryu PD, Lee SY. Selective regulation of voltage‐gated potassium channel subunits in presympathetic PVN neurons of rats with myocardial infarction (686.9). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.686.9] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Seul Ki Lee
- Laboratory of Veterinary Pharmacology College of Veterinary MedicineSeoul National UniversitySEOULRepublic of Korea
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology College of Veterinary MedicineSeoul National UniversitySEOULRepublic of Korea
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology College of Veterinary MedicineSeoul National UniversitySEOULRepublic of Korea
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33
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Lee BH, Ryu PD, Lee SY. Serum starvation-induced voltage-gated potassium channel Kv7.5 expression and its regulation by Sp1 in canine osteosarcoma cells. Int J Mol Sci 2014; 15:977-93. [PMID: 24434641 PMCID: PMC3907850 DOI: 10.3390/ijms15010977] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 12/20/2013] [Accepted: 12/30/2013] [Indexed: 01/03/2023] Open
Abstract
The KCNQ gene family, whose members encode Kv7 channels, belongs to the voltage-gated potassium (Kv) channel group. The roles of this gene family have been widely investigated in nerve and muscle cells. In the present study, we investigated several characteristics of Kv7.5, which is strongly expressed in the canine osteosarcoma cell line, CCL-183. Serum starvation upregulated Kv7.5 expression, and the Kv7 channel opener, flupirtine, attenuated cell proliferation by arresting cells in the G0/G1 phase. We also showed that Kv7.5 knockdown helps CCL-183 cells to proliferate. In an effort to find an endogenous regulator of Kv7.5, we used mithramycin A to reduce the level of the transcription factor Sp1, and it strongly inhibited the induction of Kv7.5 in CCL-183 cells. These results suggest that the activation of Kv7.5 by flupirtine may exert an anti-proliferative effect in canine osteosarcoma. Therefore, Kv7.5 is a possible molecular target for canine osteosarcoma therapy.
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Affiliation(s)
- Bo Hyung Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| | - Pan Dong Ryu
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
| | - So Yeong Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
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34
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Lee HW, Han TH, Yi KJ, Choi MC, Lee SY, Ryu PD. Time course of diurnal rhythm disturbances in autonomic function of rats with myocardial infarction. Auton Neurosci 2013; 179:28-36. [DOI: 10.1016/j.autneu.2013.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Revised: 06/17/2013] [Accepted: 06/19/2013] [Indexed: 10/26/2022]
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35
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Lee SK, Ryu PD, Lee SY. Differential distributions of neuropeptides in hypothalamic paraventricular nucleus neurons projecting to the rostral ventrolateral medulla in the rat. Neurosci Lett 2013; 556:160-5. [DOI: 10.1016/j.neulet.2013.09.070] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 09/16/2013] [Accepted: 09/28/2013] [Indexed: 10/26/2022]
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36
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Pandit S, Jeong JA, Jo JY, Cho HS, Kim DW, Kim JM, Ryu PD, Lee SY, Kim HW, Jeon BH, Park JB. Dual mechanisms diminishing tonic GABAA inhibition of dentate gyrus granule cells in Noda epileptic rats. J Neurophysiol 2013; 110:95-102. [PMID: 23576696 DOI: 10.1152/jn.00727.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [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: 11/22/2022] Open
Abstract
The Noda epileptic rat (NER), a Wistar colony mutant, spontaneously has tonic-clonic convulsions with paroxysmal discharges. In the present study, we measured phasic and tonic γ-aminobutyric acid A (GABAA) current (I tonic) in NER hippocampal dentate gyrus granule cells and compared the results with those of normal parent strain Wistar rats (WIS). I tonic, revealed by a bicuculline-induced outward shift in holding current, was significantly smaller in NER than in WIS (P < 0.01). The frequency of inhibitory postsynaptic currents (IPSCs) was also significantly lower in NER than in WIS (P < 0.05), without significant differences in the IPSC amplitude or decay time between WIS and NER. I tonic attenuation in NER was further confirmed in the presence of GABA transporter blockers, NO-711 and nipecotic acid, with no difference in neuronal GABA transporter expression between WIS and NER. I tonic responses to extrasynaptic GABAA receptor agonists (THIP and DS-2) were significantly reduced in NER compared with WIS (P < 0.05). Allopregnanolone caused less I tonic increase in NER than in WIS, while it prolonged the IPSC decay time to a similar rate in the two groups. Expression of the GABAA receptor δ-subunit was decreased in the dentate gyrus of NER relative to that of WIS. Taken together, our results showed that a combination of attenuated presynaptic GABA release and extrasynaptic GABAA receptor expression reduced I tonic amplitude and its sensitivity to neurosteroids, which likely diminishes the gating function of dentate gyrus granule cells and renders NER more susceptible to seizure propagation.
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Affiliation(s)
- Sudip Pandit
- Department of Physiology, School of Medicine and Brain Research Institute, Chungnam National University, Daejeon, South Korea
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37
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Lee SK, Ryu PD, Lee SY. Estrogen modulation of the voltage‐gated potassium channel in rat presympathetic PVN neurons. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.697.5] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Seul Ki Lee
- Seoul National UniversitySeoulRepublic of Korea
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38
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Jeon WI, Ryu PD, Lee SY. Effects of voltage-gated K+ channel blockers in gefitinib-resistant H460 non-small cell lung cancer cells. Anticancer Res 2012; 32:5279-5284. [PMID: 23225427] [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: 06/01/2023]
Abstract
Voltage-gated K(+) (Kv) channels are known to be associated with the proliferation of several types of cancer cells, including lung adenocarcinoma cells, and certain Kv channel blockers inhibit cancer cell proliferation. In the present study, we investigated the effects of Kv channel blockers in gefitinib-resistant H460 non-small cell lung cancer (NSCLC) cells. Treatment with dendrotoxin-κ (DTX-κ), which is a Kv1.1-specific blocker, reduced H460 cell viability and arrested cells in G(1)/S transition during cell-cycle progression. We administered DTX-κ in a xenograft model using nude mice. The tumor volume was reduced by the injection of DTX-κ into the tumor tissues compared to the control group. These results indicate that DTX-κ has antitumor effects in gefitinib-resistant H460 cells through the pathway governing the G(1)/S transition both in vitro and in vivo. These findings suggest that Kv1.1 could serve as a novel therapeutic target for gefitinib-resistant NSCLC.
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Affiliation(s)
- Won Il Jeon
- DVM, Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 151-742, South Korea
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Jang JH, Park JB, Kim SD, Lee SY, Hong SJ, Ryu PD. Property of large conductance Ca(2+)-activated K+ channels from Fasciola hepatica incorporated into planar lipid bilayer. Vet Parasitol 2012; 186:281-8. [PMID: 22154253 DOI: 10.1016/j.vetpar.2011.11.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 11/09/2011] [Accepted: 11/14/2011] [Indexed: 11/26/2022]
Abstract
Fasciola hepatica causes biliary epithelial hyperplasia and obstructive jaundice in humans and animals. Using a planar lipid bilayer technique, we further characterized the single channel property of large conductance K(+)-permeable channels that were previously identified from F. hepatica. The single channel conductance was 254.7±17.9 pS under a symmetrical 200/200 mM (cis/trans) KCl gradient. Open state probability (P(o)) varied from channel to channel at a given membrane potential and Ca(2+) concentration, but increased with voltage (-60 to +40 mV) and cis Ca(2+) (1-200 μM). Under a near bi-ionic condition of 200 mM [K(+)](cis)/200 mM [Na(+)](trans), the permeability ratio of K(+) to Na(+) was 5.0. Charybdotoxin (1 μM) inhibited P(o), whereas tetraethylammonium reduced the conductance (K(D)=67.8mM). Taken together, the results show that the single channel properties of the large conductance K(+)-permeable channels in F. hepatica are similar to those of large conductance Ca(2+)-activated K(+) (BK) channels in general, but distinct from typical BK channels in the extent of voltage- and Ca(2+)-dependence, as well as permeability to Na(+). This study further reveals a variant BK channel in F. hepatica that could serve as a new drug target to treat fascioliasis.
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Affiliation(s)
- Jung Hee Jang
- Department of Pharmacology, Research Institute of Veterinary Science, College of Veterinary Medicine, Seoul National University, 599 Gwanank-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
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40
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Lee SK, Ryu PD, Lee SY. Estrogen regulation of ion channel expression mediating neuronal excitability in rat presympathetic PVN neurons. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1091.49] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Seul Ki Lee
- Laboratory of Veterinary PharmacologySeoul National UniversitySeoulKorea, Republic of
| | - Pan Dong Ryu
- Laboratory of Veterinary PharmacologySeoul National UniversitySeoulKorea, Republic of
| | - So Yeong Lee
- Laboratory of Veterinary PharmacologySeoul National UniversitySeoulKorea, Republic of
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41
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Lee SK, Lee S, Shin SY, Ryu PD, Lee SY. Single cell analysis of voltage-gated potassium channels that determines neuronal types of rat hypothalamic paraventricular nucleus neurons. Neuroscience 2012; 205:49-62. [PMID: 22245500 DOI: 10.1016/j.neuroscience.2011.12.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 11/16/2011] [Accepted: 12/19/2011] [Indexed: 10/14/2022]
Abstract
The hypothalamic paraventricular nucleus (PVN), a site for the integration of both the neuroendocrine and autonomic systems, has heterogeneous cell composition. These neurons are classified into type I and type II neurons based on their electrophysiological properties. In the present study, we investigated the molecular identification of voltage-gated K+ (Kv) channels, which determines a distinctive characteristic of type I PVN neurons, by means of single-cell reverse transcription-polymerase chain reaction (RT-PCR) along with slice patch clamp recordings. In order to determine the mRNA expression profiles, firstly, the PVN neurons of male rats were classified into type I and type II neurons, and then, single-cell RT-PCR and single-cell real-time RT-PCR analysis were performed using the identical cell. The single-cell RT-PCR analysis revealed that Kv1.2, Kv1.3, Kv1.4, Kv4.1, Kv4.2, and Kv4.3 were expressed both in type I and in type II neurons, and several Kv channels were co-expressed in a single PVN neuron. However, we found that the expression densities of Kv4.2 and Kv4.3 were significantly higher in type I neurons than in type II neurons. Taken together, several Kv channels encoding A-type K+ currents are present both in type I and in type II neurons, and among those, Kv4.2 and Kv4.3 are the major Kv subunits responsible for determining the distinct electrophysiological properties. Thus these 2 Kv subunits may play important roles in determining PVN cell types and regulating PVN neuronal excitability. This study further provides key molecular mechanisms for differentiating type I and type II PVN neurons.
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Affiliation(s)
- S K Lee
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
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42
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Seo Y, Yang SR, Jee MK, Joo EK, Roh KH, Seo MS, Han TH, Lee SY, Ryu PD, Jung JW, Seo KW, Kang SK, Kang KS. Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Protect against Neuronal Cell Death and Ameliorate Motor Deficits in Niemann Pick Type C1 Mice. Cell Transplant 2011; 20:1033-47. [DOI: 10.3727/096368910x545086] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Niemann Pick disease type C1 (NPC) is an autosomal recessive disease characterized by progressive neurological deterioration leading to premature death. In this study, we hypothesized that human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) have the multifunctional abilities to ameliorate NPC symptoms in the brain. To test this hypothesis, hUCB-MSCs were transplanted into the hippocampus of NPC mice in the early asymptomatic stage. This transplantation resulted in the recovery of motor function in the Rota Rod test and impaired cholesterol homeostasis leading to increased levels of cholesterol efflux-related genes such as LXRα, ABCA1, and ABCG5 while decreased levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase were observed in NPC mice. In the cerebrum, hUCB-MSCs enhanced neuronal cell survival and proliferation, where they directly differentiated into electrically active MAP2-positive neurons as demonstrated by whole-cell patch clamping. In addition, we observed that hUCB-MSCs reduced Purkinje neuronal loss by suppression of inflammatory and apoptotic signaling in the cerebellum as shown by immunohistochemistry. We further investigated how hUCB-MSCs enhance cellular survival and inhibit apoptosis in NPC mice. Neuronal cell survival was associated with increased PI3K/AKT and JAK2/STAT3 signaling; moreover, hUCB-MSCs modulated the levels of GABA/glutamate transporters such as GAT1, EAAT2, EAAT3, and GAD6 in NPC mice as assessed by Western blot analysis. Taken together, our findings suggest that hUCB-MSCs might play multifunctional roles in neuronal cell survival and ameliorating motor deficits of NPC mice.
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Affiliation(s)
- Yoojin Seo
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Se-Ran Yang
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Min Ki Jee
- Department of Veterinary Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Eun Kyung Joo
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Kyung-Hwan Roh
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Min-Soo Seo
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Tae Hee Han
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - So Yeong Lee
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Pan Dong Ryu
- Department of Veterinary Pharmacology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Ji-Won Jung
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Kwang-Won Seo
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Soo-Kyung Kang
- Department of Veterinary Biotechnology, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Kyung-Sun Kang
- Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Laboratory of Stem Cell and Tumor Biology, Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
- Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
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Shin SY, Han TH, Lee SY, Han SK, Park JB, Erdelyi F, Szabo G, Ryu PD. Direct Corticosteroid Modulation of GABAergic Neurons in the Anterior Hypothalamic Area of GAD65-eGFP Mice. Korean J Physiol Pharmacol 2011; 15:163-9. [PMID: 21860595 DOI: 10.4196/kjpp.2011.15.3.163] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/15/2011] [Accepted: 06/15/2011] [Indexed: 02/07/2023]
Abstract
Corticosterone is known to modulate GABAergic synaptic transmission in the hypothalamic paraventricular nucleus. However, the underlying receptor mechanisms are largely unknown. In the anterior hypothalamic area (AHA), the sympathoinhibitory center that project GABAergic neurons onto the PVN, we examined the expression of glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) of GABAergic neurons using intact GAD65-eGFP transgenic mice, and the effects of corticosterone on the burst firing using adrenalectomized transgenic mice. GR or MR immunoreactivity was detected from the subpopulations of GABAergic neurons in the AHA. The AHA GABAergic neurons expressed mRNA of GR (42%), MR (38%) or both (8%). In addition, in brain slices incubated with corticosterone together with RU486 (MR-dominant group), the proportion of neurons showing a burst firing pattern was significantly higher than those in the slices incubated with vehicle, corticosterone, or corticosterone with spironolactone (GR-dominant group; 64 vs. 11~14%, p< 0.01 by χ(2)-test). Taken together, the results show that the corticosteroid receptors are expressed on the GABAergic neurons in the AHA, and can mediate the corticosteroid-induced plasticity in the firing pattern of these neurons. This study newly provides the experimental evidence for the direct glucocorticoid modulation of GABAergic neurons in the AHA in the vicinity of the PVN.
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Affiliation(s)
- Seung Yub Shin
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea
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Abstract
Voltage-gated K(+) (Kv) channels have been considered to be a regulator of membrane potential and neuronal excitability. Recently, accumulated evidence has indicated that several Kv channel subtypes contribute to the control of cell proliferation in various types of cells and are worth noting as potential emerging molecular targets of cancer therapy. In the present study, we investigated the effects of the Kv1.1-specific blocker, dendrotoxin-κ (DTX-κ, on tumor formation induced by the human lung adenocarcinoma cell line A549 in a xenograft model. Kv1.1 mRNA and protein was expressed in A549 cells and the blockade of Kv1.1 by DTX-κ, reduced tumor formation in nude mice. Furthermore, treatment with DTX-κ significantly increased protein expression of p21(Waf1/Cip1), p27(Kip1), and p15(INK4B) and significantly decreased protein expression of cyclin D3 in tumor tissues compared to the control. These results suggest that DTX-κ has anti-tumor effects in A549 cells through the pathway governing G1-S transition.
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Affiliation(s)
- Soo Hwa Jang
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea
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Kim SR, Lee SK, Jang SH, Choi JH, Lee BC, Hwang IK, Lee SY, Ryu PD. Expression of Keratin 10 in Rat Organ Surface Primo-vascular Tissues. J Acupunct Meridian Stud 2011; 4:102-6. [DOI: 10.1016/s2005-2901(11)60015-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Accepted: 02/22/2011] [Indexed: 01/04/2023] Open
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Abstract
Voltage-gated potassium (Kv) channels are expressed not only in excitable cells but also in non-excitable cells such as epithelial cells. Recent studies have demonstrated that several subtypes of Kv channels are expressed in epithelial tumor cells, including human gastric cancer cells, and are associated with cell proliferation. In the present study, we examined the expression of Kv4.1 in human gastric cancer cell lines and the effects of suppressed expression of Kv4.1 on cell proliferation and cell cycle distribution. We found that Kv4.1 mRNA and protein are expressed in the human gastric cancer cell lines MKN-45 and SNU-638. Moreover, Kv4.1-targeted small interference RNA (siRNA) treatment inhibited gastric cancer cell proliferation. Flow cytometric analysis revealed that suppressed expression of Kv4.1 induced a G1-S transition block of cell cycle progression. These results reveal that Kv4.1 plays a role in the proliferation of the human gastric cancer cell lines MKN-45 and SNU-638 and can be considered as a therapeutic target for human gastric cancer.
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Affiliation(s)
- Hyung-Jin Kim
- Laboratory of Veterinary Pathology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Korea
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Han TH, Lim CJ, Choi JH, Lee SY, Ryu PD. Viability assessment of primo-node slices from organ surface primo-vascular tissues in rats. J Acupunct Meridian Stud 2011; 3:241-8. [PMID: 21185538 DOI: 10.1016/s2005-2901(10)60043-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 10/14/2010] [Indexed: 02/04/2023] Open
Abstract
The primo-vascular system is a novel thread-like structure which is recently rediscovered, but its cellular properties are largely unknown. In this study, a slice preparation for primo-nodes was developed to facilitate study of the cellular properties of primo-node cells in vitro. Slices (4-8 slices; 200 μm thick) were sectioned from single primo-nodes collected from the abdominal organ surface of rats and incubated in oxygenated Krebs solution at 25°C or 31°C for up to 7 hours. Trypan blue staining and whole-cell patch-clamp recordings were performed to estimate the viability of cells in the slices. Viability was largely maintained during the first 3 hours, but subsequently decreased (from 80% to 21%, p < 0.001). In addition, the viability of slices incubated at 31°C was higher than those incubated at 25°C (80%vs. 47%, p < 0.001). In whole-cell patch-clamp experiments, high resistance seals readily formed and primo-node cells showed a mean resting membrane potential (-38 mV) comparable to that recorded with sharp electrodes and outwardly-rectifying current-voltage relationships. The results show that the primo-node slices developed in this study maintained viability for up to 4 hours in vitro.
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Affiliation(s)
- Tae Hee Han
- Laboratory of Veterinary Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
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Bhattarai JP, Park SA, Park JB, Lee SY, Herbison AE, Ryu PD, Han SK. Tonic extrasynaptic GABA(A) receptor currents control gonadotropin-releasing hormone neuron excitability in the mouse. Endocrinology 2011; 152:1551-61. [PMID: 21285326 DOI: 10.1210/en.2010-1191] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [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: 12/18/2022]
Abstract
It is well established that the GABA(A) receptor plays an important role in regulating the electrical excitability of GnRH neurons. Two different modes of GABA(A) receptor signaling exist: one mediated by synaptic receptors generating fast (phasic) postsynaptic currents and the other mediated by extrasynaptic receptors generating a persistent (tonic) current. Using GABA(A) receptor antagonists picrotoxin, bicuculline methiodide, and gabazine, which differentiate between phasic and tonic signaling, we found that ∼50% of GnRH neurons exhibit an approximately 15-pA tonic GABA(A) receptor current in the acute brain slice preparation. The blockade of either neuronal (NO711) or glial (SNAP-5114) GABA transporter activity within the brain slice revealed the presence of tonic GABA signaling in ∼90% of GnRH neurons. The GABA(A) receptor δ subunit is only found in extrasynaptic GABA(A) receptors. Using single-cell RT-PCR, GABA(A) receptor δ subunit mRNA was identified in GnRH neurons and the δ subunit-specific agonist 4,5,6,7-tetrahydroisoxazolo [5,4-c] pyridin-3-ol was found to activate inward currents in GnRH neurons. Perforated-patch clamp studies showed that 4,5,6,7-tetrahydroisoxazolo [5,4-c] pyridin-3-ol exerted the same depolarizing or hyperpolarizing effects as GABA on juvenile and adult GnRH neurons and that tonic GABA(A) receptor signaling regulates resting membrane potential. Together, these studies reveal the presence of a tonic GABA(A) receptor current in GnRH neurons that controls their excitability. The level of tonic current is dependent, in part, on neuronal and glial GABA transporter activity and mediated by extrasynaptic δ subunit-containing GABA(A) receptors.
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Affiliation(s)
- Janardhan P Bhattarai
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, Jeonju, 561-756, Korea
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Jo JY, Jeong JA, Pandit S, Stern JE, Lee SK, Ryu PD, Lee SY, Han SK, Cho CH, Kim HW, Jeon BH, Park JB. Neurosteroid modulation of benzodiazepine-sensitive GABAA tonic inhibition in supraoptic magnocellular neurons. Am J Physiol Regul Integr Comp Physiol 2011; 300:R1578-87. [PMID: 21451144 DOI: 10.1152/ajpregu.00627.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Interactions between neurosteroids and GABA receptors have attracted particular attention in the supraoptic nucleus (SON). Although GABA(A) receptors (GABA(A)R) mediate a sustained tonic inhibitory current (I(tonic)), as well as conventional phasic inhibitory postsynaptic currents (IPSCs, I(phasic)) in the SON, whether the steroid modulation on I(tonic) is present in SON magnocelluar neurosecretory cells (MNCs) is unknown. Here, we addressed this question and gained insights into the potential molecular configuration of GABA(A) receptors mediating I(tonic) and conferring its neurosteroids sensitivity in SON MNCs. 4,5,6,7-tetrahydroisoxazolo[5,4-c]-pyridin-3-ol (THIP) (1 μM), a relatively selective extrasynaptic GABA(A)R agonist, facilitated I(tonic) without affecting the main characteristics of IPSCs, while DS-2, a relatively selective modulator of GABA(A)R δ-subunits, caused minimal changes in I(tonic) of SON MNCs. l-655,708, a relatively selective GABA(A)R α(5)-subunit inverse agonist, blocked ∼35% of the total I(tonic) both under basal and elevated ambient GABA concentration (3 μM). Facilitation of I(tonic) by benzodiazepines further supported the role of GABA(A)R γ(2)-subunit in I(tonic) of SON MNCs. Quantitative RT-PCR analysis showed much lesser expression of GABA(A)R δ-subunit than the α(5) or γ(2)-subunit in the SON. Allopregnanolone and 3α,5α-tetrahydrodeoxycorticosterone increased both I(tonic) and I(phasic) in SON MNCs, respectively, although more than 90% of the current increase was mediated by I(tonic) during the neurosteroid facilitation. Finally, l-655,708 attenuated the neurosteroid facilitation of I(tonic) but not of I(phasic). Altogether, our results suggest that I(tonic), mediated mainly by benzodiazepine-sensitive GABA(A)Rs containing α(5)-, β-, and γ(2)-, and to a lesser extent, δ-subunits, is a potential target of neurosteroid modulation in SON neurons.
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Affiliation(s)
- Ji Yoon Jo
- Department of Physiology, School of Medicine, Chungnam National University, Daejeon, Korea
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Sonner PM, Lee S, Ryu PD, Lee SY, Stern JE. Imbalanced K+ and Ca2+ subthreshold interactions contribute to increased hypothalamic presympathetic neuronal excitability in hypertensive rats. J Physiol 2011; 589:667-83. [PMID: 21149460 PMCID: PMC3055550 DOI: 10.1113/jphysiol.2010.198556] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [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: 08/25/2010] [Accepted: 12/09/2010] [Indexed: 12/12/2022] Open
Abstract
Despite the importance of brain-mediated sympathetic activation in the morbidity and mortality of patients with high blood pressure, the precise cellular mechanisms involved remain largely unknown. We show that an imbalanced interaction between two opposing currents mediated by potassium (I(A)) and calcium (I(T)) channels occurs in sympathetic-related hypothalamic neurons in hypertensive rats. We show that this imbalance contributes to enhanced membrane excitability and firing activity in this neuronal population. Knowledge of how these opposing ion channels interact in normal and disease states increases our understanding of underlying brain mechanisms contributing to the high blood pressure condition.
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Affiliation(s)
- P M Sonner
- Department of Physiology, Medical College of Georgia, Augusta, GA 30912, USA
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