1
|
Jang J, Kim SH, Um KB, Kim HJ, Park MK. Somatodendritic organization of pacemaker activity in midbrain dopamine neurons. Korean J Physiol Pharmacol 2024; 28:165-181. [PMID: 38414399 PMCID: PMC10902590 DOI: 10.4196/kjpp.2024.28.2.165] [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] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 02/29/2024]
Abstract
The slow and regular pacemaking activity of midbrain dopamine (DA) neurons requires proper spatial organization of the excitable elements between the soma and dendritic compartments, but the somatodendritic organization is not clear. Here, we show that the dynamic interaction between the soma and multiple proximal dendritic compartments (PDCs) generates the slow pacemaking activity in DA neurons. In multipolar DA neurons, spontaneous action potentials (sAPs) consistently originate from the axon-bearing dendrite. However, when the axon initial segment was disabled, sAPs emerge randomly from various primary PDCs, indicating that multiple PDCs drive pacemaking. Ca2+ measurements and local stimulation/perturbation experiments suggest that the soma serves as a stably-oscillating inertial compartment, while multiple PDCs exhibit stochastic fluctuations and high excitability. Despite the stochastic and excitable nature of PDCs, their activities are balanced by the large centrally-connected inertial soma, resulting in the slow synchronized pacemaking rhythm. Furthermore, our electrophysiological experiments indicate that the soma and PDCs, with distinct characteristics, play different roles in glutamate- induced burst-pause firing patterns. Excitable PDCs mediate excitatory burst responses to glutamate, while the large inertial soma determines inhibitory pause responses to glutamate. Therefore, we could conclude that this somatodendritic organization serves as a common foundation for both pacemaker activity and evoked firing patterns in midbrain DA neurons.
Collapse
Affiliation(s)
- Jinyoung Jang
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Shin Hye Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Ki Bum Um
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Myoung Kyu Park
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| |
Collapse
|
2
|
Jo S, Lee SH, Jo HR, Weon S, Jeon C, Park MK, Kim TH, Cho SH. Eosinophil-derived TGFβ1 controls the new bone formation in chronic rhinosinusitis with nasal polyps. Rhinology 2023; 61:338-347. [PMID: 37083114 DOI: 10.4193/rhin22.439] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
BACKGROUND Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by chronic eosinophilic inflammation and new bone formation (NBF). These processes may be associated with each other in the pathogenesis and influence the severity and prognosis of the disease. However, it is still unclear how eosinophilic inflammation is involved in the NBF. METHODOLOGY Sinus bone cells were isolated from ethmoid bone tissues of patients with CRSwNP and controls. Transforming growth factor beta 1 (TGFβ1) and alkaline phosphatase (ALP) expression in sinus bone cells was determined using quantitative RT-PCR, immunoblotting, and immunohistochemistry. The co-localization of TGFβ1 with eosinophils was assessed by immunofluorescence staining. Sinus bone cells were co-cultured with eosinophils (Eol-1 cell line), which were differentiated with butyrate, to measure the osteoblast differentiation activity of sinus bone cells. RESULTS TGFβ1 expression was increased in sinus bone tissues and correlated with CT scores in CRSwNP. TGFβ1 was also increased in the submucosa of CRSwNP and co-localized predominantly with eosinophils compared with neutrophils Differentiated Eol-1 cells-derived TGFβ1 increased ALP expression in sinus bone cells. Treatment with a TGFβ inhibitor attenuated TGFβ1-induced ALP expression and staining in sinus bone cells of CRSwNP, leading to loss of bone formation. CONCLUSIONS Eosinophil-derived TGFβ1 was enriched in the submucosa of CRSwNP, which induced ALP expression in sinus bone cells and NBF. Therefore, eosinophil-derived TGFβ1 may mediate aberrant bone remodeling in CRSwNP.
Collapse
Affiliation(s)
- S Jo
- Hanyang University Institute for Rheumatology Research (HYIRR), Hanyang University, Seoul, Republic of Korea
| | - S H Lee
- Hanyang University Institute for Rheumatology Research (HYIRR), Hanyang University, Seoul, Republic of Korea
| | - H-R Jo
- Hanyang University Institute for Rheumatology Research (HYIRR), Hanyang University, Seoul, Republic of Korea
| | - S Weon
- Hanyang University Institute for Rheumatology Research (HYIRR), Hanyang University, Seoul, Republic of Korea
| | - C Jeon
- Hanyang University Institute for Rheumatology Research (HYIRR), Hanyang University, Seoul, Republic of Korea
| | - M K Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - T-H Kim
- Hanyang University Institute for Rheumatology Research (HYIRR), Hanyang University, Seoul, Republic of Korea; Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea
| | - S H Cho
- Department of Otorhinolaryngology-Head and Neck Surgery, Hanyang University College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
3
|
Hahn S, Um KB, Kim SW, Kim HJ, Park MK. Proximal dendritic localization of NALCN channels underlies tonic and burst firing in nigral dopaminergic neurons. J Physiol 2023; 601:171-193. [PMID: 36398712 DOI: 10.1113/jp283716] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [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: 08/10/2022] [Accepted: 11/14/2022] [Indexed: 11/19/2022] Open
Abstract
In multipolar nigral dopamine (DA) neurons, the highly excitable proximal dendritic compartments (PDCs) and two Na+ -permeable leak channels, TRPC3 and NALCN, play a key role in pacemaking. However, the causal link between them is unknown. Here we report that the proximal dendritic localization of NALCN underlies pacemaking and burst firing in DA neurons. Our morphological analysis of nigral DA neurons reveals that TRPC3 is ubiquitously expressed in the whole somatodendritic compartment, but NALCN is localized within the PDCs. Blocking either TRPC3 or NALCN channels abolished pacemaking. However, only blocking NALCN, not TRPC3, degraded burst discharges. Furthermore, local glutamate uncaging readily induced burst discharges within the PDCs, compared with other parts of the neuron, and NALCN channel inhibition dissipated burst generation, indicating the importance of NALCN to the high excitability of PDCs. Therefore, we conclude that PDCs serve as a common base for tonic and burst firing in nigral DA neurons. KEY POINTS: Midbrain dopamine (DA) neurons are slow pacemakers that can generate tonic and burst firings, and the highly excitable proximal dendritic compartments (PDCs) and two Na+ -permeable leak channels, TRPC3 and NALCN, play a key role in pacemaking. We find that slow tonic firing depends on the basal activity of both the NALCN and TRPC3 channels, but that burst firing does not require TRPC3 channels but relies only on NALCN channels. We find that TRPC3 is ubiquitously expressed in the entire somatodendritic compartment, but that NALCN exists only within the PDCs in nigral DA neurons. We show that NALCN channel localization confers high excitability on PDCs and is essential for burst generation in nigral DA neurons. These results suggest that PDCs serve as a common base for tonic and burst firing in nigral DA neurons.
Collapse
Affiliation(s)
- Suyun Hahn
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Ki Bum Um
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - So Woon Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea.,Samsung Medical Center, Samsung Biomedical Research Institute, Seoul, Korea
| | - Myoung Kyu Park
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea.,Samsung Medical Center, Samsung Biomedical Research Institute, Seoul, Korea
| |
Collapse
|
4
|
Um KB, Hahn S, Kim SW, Lee YJ, Birnbaumer L, Kim HJ, Park MK. TRPC3 and NALCN channels drive pacemaking in substantia nigra dopaminergic neurons. eLife 2021; 10:70920. [PMID: 34409942 PMCID: PMC8456572 DOI: 10.7554/elife.70920] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [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: 06/02/2021] [Accepted: 08/18/2021] [Indexed: 01/16/2023] Open
Abstract
Midbrain dopamine (DA) neurons are slow pacemakers that maintain extracellular DA levels. During the interspike intervals, subthreshold slow depolarization underlies autonomous pacemaking and determines its rate. However, the ion channels that determine slow depolarization are unknown. Here we show that TRPC3 and NALCN channels together form sustained inward currents responsible for the slow depolarization of nigral DA neurons. Specific TRPC3 channel blockade completely blocked DA neuron pacemaking, but the pacemaking activity in TRPC3 knock-out (KO) mice was perfectly normal, suggesting the presence of compensating ion channels. Blocking NALCN channels abolished pacemaking in both TRPC3 KO and wild-type mice. The NALCN current and mRNA and protein expression are increased in TRPC3 KO mice, indicating that NALCN compensates for TRPC3 currents. In normal conditions, TRPC3 and NALCN contribute equally to slow depolarization. Therefore, we conclude that TRPC3 and NALCN are two major leak channels that drive robust pacemaking in nigral DA neurons.
Collapse
Affiliation(s)
- Ki Bum Um
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Suyun Hahn
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - So Woon Kim
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Yoon Je Lee
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Lutz Birnbaumer
- Neurobiology Laboratory. National Institute of Environmental Health Sciences, North Carolina 27709, USA; and Institute of Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, Argentina
| | - Hyun Jin Kim
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Republic of Korea
| | - Myoung Kyu Park
- Department of physiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Republic of Korea
| |
Collapse
|
5
|
Han MC, Kim J, Hong CS, Chang KH, Han SC, Park K, Kim DW, Park MK, Noh YY, Kim JS. Assessment of dosimetric leaf gap correction factor in Mobius3D commissioning affected by couch top. Phys Eng Sci Med 2020; 43:1069-1075. [PMID: 32700205 DOI: 10.1007/s13246-020-00905-z] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/14/2020] [Indexed: 11/29/2022]
Abstract
This study assesses the dosimetric leaf gap (DLG) correction factor in Mobius3D commissioning affected by a couch top platform and calculates the optimal DLG value according to the point dose difference function. DLG optimizations were performed for 3 LINAC machines and a total of 30 patient volumetric modulated arc therapy plans (i.e., 10 plans per each LINAC). Point dose calculations were performed using an automatic dose calculation system in Mobius3D as well as Mobis3D calculation using a Mobius Verification Phantom (MVP)-based quality assurance plan with a carbon fiber couch top. Subsequently, the results were compared with measurement data. The averaged point dose measured for the MVP with a couch top decreased by approximately 2% relative to that without the couch top. The average of the optimal DLG factors increased by 1.153 mm due to the couch top effect for a dose decrease of 2% at the measured point. In the procedure of Mobius beam commissioning, users should adjust the DLG correction factor using a specific phantom (including MVP) with a couch top structure. If the DLG optimization were performed by using MVP automatic dose calculation system, the factor should be increased by approximately 1.2 mm per 2% dose difference considering user's couch top effect.
Collapse
Affiliation(s)
- Min Cheol Han
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Jihun Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Chae-Seon Hong
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
| | - Kyung Hwan Chang
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Su Chul Han
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Kwangwoo Park
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Dong Wook Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea
| | - Myoung Kyu Park
- Department of Radiation Oncology, Yonsei Cancer Center, Seoul, South Korea
| | - Yu Yun Noh
- Department of Radiation Oncology, Yonsei Cancer Center, Seoul, South Korea
| | - Jin Sung Kim
- Department of Radiation Oncology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, South Korea.
| |
Collapse
|
6
|
Hahn S, Kim SW, Um KB, Kim HJ, Park MK. N-benzhydryl quinuclidine compounds are a potent and Src kinase-independent inhibitor of NALCN channels. Br J Pharmacol 2020; 177:3795-3810. [PMID: 32436268 DOI: 10.1111/bph.15104] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 05/01/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE NALCN is a Na+ leak, GPCR-activated channel that regulates the resting membrane potential and neuronal excitability. Despite numerous possible roles for NALCN in both normal physiology and disease processes, lack of specific blockers hampers further investigation. EXPERIMENTAL APPROACH The effect of N-benzhydryl quinuclidine compounds on NALCN channels was demonstrated using whole-cell patch-clamp recordings in HEK293T cells overexpressing NALCN and acutely isolated nigral dopaminergic neurons that express NALCN endogenously. Src kinase activity was measured using a Src kinase assay kit, and voltage and current-clamp recordings from nigral dopaminergic neurons were used to measure NALCN currents and membrane potentials. KEY RESULTS N-benzhydryl quinuclidine compounds inhibited NALCN channels without affecting TRPC channels, another important route for Na+ leak. In HEK293T cells overexpressing NALCN, N-benzhydryl quinuclidine compounds potently suppressed muscarinic M3 receptor-activated NALCN currents. Structure-function relationship studies suggest that the quinuclidine ring with a benzhydryl group imparts the ability to inhibit NALCN currents regardless of Src family kinases. Moreover, N-benzhydryl quinuclidine compounds inhibited not only GPCR-activated NALCN currents but also background Na+ leak currents and hyperpolarized the membrane potential in native midbrain dopaminergic neurons that express NALCN endogenously. CONCLUSION AND IMPLICATIONS These findings suggest that N-benzhydryl quinuclidine compounds have a pharmacological potential to directly inhibit NALCN channels and could be a useful tool to investigate functions of NALCN channels.
Collapse
Affiliation(s)
- Suyun Hahn
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - So Woon Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Ki Bum Um
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea
| | - Myoung Kyu Park
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Korea
| |
Collapse
|
7
|
Kim Y, Jang J, Kim HJ, Park MK. Regional difference in spontaneous firing inhibition by GABA A and GABA B receptors in nigral dopamine neurons. Korean J Physiol Pharmacol 2018; 22:721-729. [PMID: 30402033 PMCID: PMC6205942 DOI: 10.4196/kjpp.2018.22.6.721] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/04/2018] [Accepted: 10/04/2018] [Indexed: 01/18/2023]
Abstract
GABAergic control over dopamine (DA) neurons in the substantia nigra is crucial for determining firing rates and patterns. Although GABA activates both GABAA and GABAB receptors distributed throughout the somatodendritic tree, it is currently unclear how regional GABA receptors in the soma and dendritic compartments regulate spontaneous firing. Therefore, the objective of this study was to determine actions of regional GABA receptors on spontaneous firing in acutely dissociated DA neurons from the rat using patch-clamp and local GABA-uncaging techniques. Agonists and antagonists experiments showed that activation of either GABAA receptors or GABAB receptors in DA neurons is enough to completely abolish spontaneous firing. Local GABA-uncaging along the somatodendritic tree revealed that activation of regional GABA receptors limited within the soma, proximal, or distal dendritic region, can completely suppress spontaneous firing. However, activation of either GABAA or GABAB receptor equally suppressed spontaneous firing in the soma, whereas GABAB receptor inhibited spontaneous firing more strongly than GABAA receptor in the proximal and distal dendrites. These regional differences of GABA signals between the soma and dendritic compartments could contribute to our understanding of many diverse and complex actions of GABA in midbrain DA neurons.
Collapse
Affiliation(s)
- Yumi Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Jinyoung Jang
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 06351, Korea
| | - Myoung Kyu Park
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 06351, Korea
| |
Collapse
|
8
|
Bang YK, Park MK, Ju YS, Cho KY. Clinical significance of nutritional risk screening tool for hospitalised children with acute burn injuries: a cross-sectional study. J Hum Nutr Diet 2017; 31:370-378. [PMID: 28948659 DOI: 10.1111/jhn.12518] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND We assessed the nutritional risks among children hospitalised with acute burn injuries and their associated clinical outcomes using three nutritional risk screening (NRS) tools: Screening Tool for Risk of Impaired Nutritional Status and Growth (STRONGKIDS ), Pediatric Yorkhill Malnutrition Score (PYMS) and Screening Tool for the Assessment for Malnutrition in Pediatrics (STAMP). METHODS This prospective cross-sectional study was conducted from October 2015 to November 2016, in a regional burn centre. Patients were screened by two independent observers, using the three NRS tools. RESULTS A total of 100 children aged 3 months to 16.5 years were included. STRONGKIDS identified 16% of patients as having high risk, with being identified 45% by PYMS and 44% by STAMP. After adjustment for confounding factors in multivariate regression analysis, patients in the high-risk group had significantly longer median (SD) lengths of stay [medium versus high risk: STRONGKIDS , 9.5 (6.6) versus 15.0 (24.2) days; PYMS, 8.5 (4.4) versus 13.0 (16.1) days; STAMP, 9.0 (5.7) versus 11.0 (17.4) days] and greater median (SD) weight loss [medium versus high risk: STRONGKIDS, 0.15 (0.8) versus -0.35 (0.8) kg; STAMP, 0.5 (0.7) versus 0 (0.1) kg] than patients in the medium-risk group (P < 0.05). The strengths of agreement in the nutritional risk classification between the two observers were good (κ for STRONGKIDS = 0.61; PYMS = 0.79; STAMP = 0.75) (P < 0.01). CONCLUSIONS The STRONGKIDS , PYMS and STAMP tools could be useful and practical for determining which hospitalised children with acute burn injuries will need additional nutritional intervention.
Collapse
Affiliation(s)
- Y K Bang
- Departments of Pediatrics, KEPCO Medical Center, Seoul, Korea
| | - M K Park
- Departments of Pediatrics, KEPCO Medical Center, Seoul, Korea
| | - Y S Ju
- Department of Occupational and Environmental Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang-si, Gyeonggi-do, Korea
| | - K Y Cho
- Department of Pediatrics, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea
| |
Collapse
|
9
|
Park MK, Li W, Paek SY, Li X, Wu S, Li T, Qureshi AA, Cho E. Consumption of polyunsaturated fatty acids and risk of incident psoriasis and psoriatic arthritis from the Nurses' Health Study II. Br J Dermatol 2017; 177:302-306. [PMID: 27628705 DOI: 10.1111/bjd.15059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- M K Park
- Department of Dermatology, The Warren Alpert Medical School of Brown University, Providence, RI, U.S.A
| | - W Li
- Department of Dermatology, The Warren Alpert Medical School of Brown University, Providence, RI, U.S.A.,Department of Epidemiology, Brown School of Public Health, Providence, RI, U.S.A.,Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, U.S.A
| | - S Y Paek
- Department of Dermatology, The Warren Alpert Medical School of Brown University, Providence, RI, U.S.A
| | - X Li
- Department of Epidemiology, Harvard T.H Chan School of Public Health, Boston, MA, U.S.A
| | - S Wu
- Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, Beijing, China
| | - T Li
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, U.S.A
| | - A A Qureshi
- Department of Dermatology, The Warren Alpert Medical School of Brown University, Providence, RI, U.S.A.,Department of Epidemiology, Brown School of Public Health, Providence, RI, U.S.A.,Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, U.S.A
| | - E Cho
- Department of Dermatology, The Warren Alpert Medical School of Brown University, Providence, RI, U.S.A.,Department of Epidemiology, Brown School of Public Health, Providence, RI, U.S.A.,Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, U.S.A
| |
Collapse
|
10
|
Lee JY, Park JH, Choi HJ, Won HY, Joo HS, Shin DH, Park MK, Han B, Kim KP, Lee TJ, Croce CM, Kong G. LSD1 demethylates HIF1α to inhibit hydroxylation and ubiquitin-mediated degradation in tumor angiogenesis. Oncogene 2017; 36:5512-5521. [PMID: 28534506 DOI: 10.1038/onc.2017.158] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 04/02/2017] [Accepted: 04/18/2017] [Indexed: 12/15/2022]
Abstract
Lysine-specific demethylase 1 (LSD1), which has been considered as a potential therapeutic target in human cancer, has been known to regulate many biological functions through its non-histone substrates. Although LSD1-induced hypoxia-inducible factor alpha (HIF1α) demethylation has recently been proposed, the effect of LSD1 on the relationship between HIF1α post-translational modifications (PTMs) and HIF1α-induced tumor angiogenesis remains to be elucidated. Here, we identify a new methylation site of the HIF1α protein antagonized by LSD1 and the interplay between HIF1α protein methylation and other PTMs in regulating tumor angiogenesis. LSD1 demethylates HIF1α at lysine (K) 391, which protects HIF1α against ubiquitin-mediated protein degradation. LSD1 also directly suppresses PHD2-induced HIF1α hydroxylation, which has a mutually dependent interplay with Set9-mediated HIF1α methylation. Moreover, the HIF1α acetylation that occurs in a HIF1α methylation-dependent manner is inhibited by the LSD1/NuRD complex. HIF1α stabilized by LSD1 cooperates with CBP and MTA1 to enhance vascular endothelial growth factor (VEGF)-induced tumor angiogenesis. Thus, LSD1 is a key regulator of HIF1α/VEGF-mediated tumor angiogenesis by antagonizing the crosstalk between PTMs involving HIF1α protein degradation.
Collapse
Affiliation(s)
- J-Y Lee
- Institute for Bioengineering and Biopharmaceutical Research (IBBR), Hanyang University, Seoul, Republic of Korea
| | - J-H Park
- Institute for Bioengineering and Biopharmaceutical Research (IBBR), Hanyang University, Seoul, Republic of Korea
| | - H-J Choi
- Department of Pathology, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - H-Y Won
- Department of Pathology, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - H-S Joo
- Department of Pathology, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - D-H Shin
- Department of Pathology, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - M K Park
- National Cancer Center, Goyang, Republic of Korea
| | - B Han
- Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin, Korea
| | - K P Kim
- Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin, Korea
| | - T J Lee
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, OH, USA
| | - C M Croce
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, OH, USA
| | - G Kong
- Institute for Bioengineering and Biopharmaceutical Research (IBBR), Hanyang University, Seoul, Republic of Korea.,Department of Pathology, College of Medicine, Hanyang University, Seoul, Republic of Korea
| |
Collapse
|
11
|
Huseinovic E, Winkvist A, Slimani N, Park MK, Freisling H, Boeing H, Buckland G, Schwingshackl L, Weiderpass E, Rostgaard-Hansen AL, Tjønneland A, Affret A, Boutron-Ruault MC, Fagherazzi G, Katzke V, Kühn T, Naska A, Orfanos P, Trichopoulou A, Pala V, Palli D, Ricceri F, Santucci de Magistris M, Tumino R, Engeset D, Enget T, Skeie G, Barricarte A, Bonet CB, Chirlaque MD, Amiano P, Quirós JR, Sánchez MJ, Dias JA, Drake I, Wennberg M, Boer JMA, Ocké MC, Verschuren WMM, Lassale C, Perez-Cornago A, Riboli E, Ward H, Forslund HB. Meal patterns across ten European countries - results from the European Prospective Investigation into Cancer and Nutrition (EPIC) calibration study. Public Health Nutr 2016; 19:2769-80. [PMID: 27194183 PMCID: PMC10271196 DOI: 10.1017/s1368980016001142] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/23/2016] [Accepted: 04/14/2016] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To characterize meal patterns across ten European countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) calibration study. DESIGN Cross-sectional study utilizing dietary data collected through a standardized 24 h diet recall during 1995-2000. Eleven predefined intake occasions across a 24 h period were assessed during the interview. In the present descriptive report, meal patterns were analysed in terms of daily number of intake occasions, the proportion reporting each intake occasion and the energy contributions from each intake occasion. SETTING Twenty-seven centres across ten European countries. SUBJECTS Women (64 %) and men (36 %) aged 35-74 years (n 36 020). RESULTS Pronounced differences in meal patterns emerged both across centres within the same country and across different countries, with a trend for fewer intake occasions per day in Mediterranean countries compared with central and northern Europe. Differences were also found for daily energy intake provided by lunch, with 38-43 % for women and 41-45 % for men within Mediterranean countries compared with 16-27 % for women and 20-26 % for men in central and northern European countries. Likewise, a south-north gradient was found for daily energy intake from snacks, with 13-20 % (women) and 10-17 % (men) in Mediterranean countries compared with 24-34 % (women) and 23-35 % (men) in central/northern Europe. CONCLUSIONS We found distinct differences in meal patterns with marked diversity for intake frequency and lunch and snack consumption between Mediterranean and central/northern European countries. Monitoring of meal patterns across various cultures and populations could provide critical context to the research efforts to characterize relationships between dietary intake and health.
Collapse
Affiliation(s)
- E Huseinovic
- Department of Internal Medicine and Clinical Nutrition, The Sahlgrenska Academy, University of Gothenburg, Box 459, SE-405 30, Gothenburg, Sweden
| | - A Winkvist
- Department of Internal Medicine and Clinical Nutrition, The Sahlgrenska Academy, University of Gothenburg, Box 459, SE-405 30, Gothenburg, Sweden
- Department of Public Health and Clinical Medicine, Nutritional Research, Umeå University, Umeå, Sweden
| | - N Slimani
- Dietary Exposure Assessment Group, International Agency for Research on Cancer, Lyon, France
| | - MK Park
- Dietary Exposure Assessment Group, International Agency for Research on Cancer, Lyon, France
| | - H Freisling
- Dietary Exposure Assessment Group, International Agency for Research on Cancer, Lyon, France
| | - H Boeing
- Department of Epidemiology, German Institute of Human Nutrition, Nuthetal, Germany
| | - G Buckland
- Unit of Nutrition and Cancer, Cancer Epidemiology Research Programme, Catalan Institute of Oncology (ICO-IDIBELL), Barcelona, Spain
| | - L Schwingshackl
- Department of Epidemiology, German Institute of Human Nutrition, Nuthetal, Germany
| | - E Weiderpass
- Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway
- Department of Research, Cancer Registry of Norway – Institute of Population-Based Cancer Research, Oslo, Norway
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Genetic Epidemiology Group, Folkhälsan Research Center, Helsinki, Finland
| | | | - A Tjønneland
- Danish Cancer Society Research Center, Copenhagen, Denmark
| | - A Affret
- Université Paris-Saclay, Université Paris-Sud, UVSQ, CESP, INSERM, Villejuif, France
- Gustave Roussy, Villejuif, France
| | - MC Boutron-Ruault
- Université Paris-Saclay, Université Paris-Sud, UVSQ, CESP, INSERM, Villejuif, France
- Gustave Roussy, Villejuif, France
| | - G Fagherazzi
- Université Paris-Saclay, Université Paris-Sud, UVSQ, CESP, INSERM, Villejuif, France
- Gustave Roussy, Villejuif, France
| | - V Katzke
- German Cancer Research Center (DKFZ), Division of Cancer Epidemiology, Heidelberg, Germany
| | - T Kühn
- German Cancer Research Center (DKFZ), Division of Cancer Epidemiology, Heidelberg, Germany
| | - A Naska
- Hellenic Health Foundation, Athens, Greece
- WHO Collaborating Center for Nutrition and Health, Unit of Nutritional Epidemiology and Nutrition in Public Health, Department of Hygiene, Epidemiology and Medical Statistics, University of Athens Medical School, Athens, Greece
| | - P Orfanos
- Hellenic Health Foundation, Athens, Greece
- WHO Collaborating Center for Nutrition and Health, Unit of Nutritional Epidemiology and Nutrition in Public Health, Department of Hygiene, Epidemiology and Medical Statistics, University of Athens Medical School, Athens, Greece
| | - A Trichopoulou
- Hellenic Health Foundation, Athens, Greece
- WHO Collaborating Center for Nutrition and Health, Unit of Nutritional Epidemiology and Nutrition in Public Health, Department of Hygiene, Epidemiology and Medical Statistics, University of Athens Medical School, Athens, Greece
| | - V Pala
- Epidemiology and Prevention Unit, Department of Preventive and Predictive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - D Palli
- Molecular and Nutritional Epidemiology Unit, Cancer Research and Prevention Institute – ISPO, Florence, Italy
| | - F Ricceri
- Unit of Epidemiology, Regional Health Service ASL TO3, Grugliasco (TO), Italy
- Unit of Cancer Epidemiology, Department of Medical Sciences, University of Turin, Turin, Italy
| | | | - R Tumino
- Cancer Registry and Histopathology Unit, ‘Civic – M.P. Arezzo’ Hospital, ASP Ragusa, Ragusa, Italy
| | - D Engeset
- Norwegian Food Safety Authority, Head Office, Oslo, Norway
| | - T Enget
- Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway
| | - G Skeie
- Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway
| | - A Barricarte
- Navarra Public Health Institute, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
- CIBER Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - CB Bonet
- Unit of Nutrition and Cancer, Cancer Epidemiology Research Programme, Catalan Institute of Oncology (ICO-IDIBELL), Barcelona, Spain
| | - MD Chirlaque
- CIBER Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Department of Epidemiology, Regional Health Council, IMIB-Arrixaca, Murcia, Spain
- Department of Health and Social Sciences, Universidad de Murcia, Murcia, Spain
| | - P Amiano
- CIBER Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Public Health Division of Gipuzkoa, BioDonostia Research Institute, San Sebastian, Spain
| | - JR Quirós
- Public Health Directorate, Asturias, Spain
| | - MJ Sánchez
- CIBER Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Escuela Andaluza de Salud Pública, Instituto de Investigación Biosanitaria ibs.GRANADA, Hospitales Universitarios de Granada/Universidad de Granada, Granada, Spain
| | - JA Dias
- Department of Clinical Sciences in Malmö, Lund University, Lund, Sweden
| | - I Drake
- Department of Clinical Sciences in Malmö, Lund University, Lund, Sweden
| | - M Wennberg
- Department of Public Health and Clinical Medicine, Nutritional Research, Umeå University, Umeå, Sweden
| | - JMA Boer
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - MC Ocké
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - WMM Verschuren
- Centre for Nutrition, Prevention and Health Services, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - C Lassale
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - A Perez-Cornago
- Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - E Riboli
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - H Ward
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - H Bertéus Forslund
- Department of Internal Medicine and Clinical Nutrition, The Sahlgrenska Academy, University of Gothenburg, Box 459, SE-405 30, Gothenburg, Sweden
| |
Collapse
|
12
|
Kim Y, Oh HG, Cho YY, Kwon OH, Park MK, Chung S. Stress hormone potentiates Zn 2+ -induced neurotoxicity via TRPM7 channel in dopaminergic neuron. Biochem Biophys Res Commun 2016; 470:362-367. [DOI: 10.1016/j.bbrc.2016.01.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 01/07/2016] [Indexed: 12/14/2022]
|
13
|
Chun YS, Kwon OH, Oh HG, Kim TW, McIntire L, Park MK, Chung S. Threonine 576 residue of amyloid-β precursor protein regulates its trafficking and processing. Biochem Biophys Res Commun 2015; 467:955-60. [DOI: 10.1016/j.bbrc.2015.10.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 02/08/2023]
|
14
|
Chun YS, Park Y, Oh HG, Kim TW, Yang HO, Park MK, Chung S. O-GlcNAcylation promotes non-amyloidogenic processing of amyloid-β protein precursor via inhibition of endocytosis from the plasma membrane. J Alzheimers Dis 2015; 44:261-75. [PMID: 25208619 DOI: 10.3233/jad-140096] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [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: 11/15/2022]
Abstract
Amyloid-β protein precursor (AβPP) is transported to the plasma membrane, where it is sequentially cleaved by α-secretase and γ-secretase. This is called non-amyloidogenic pathway since it precludes the production of amyloid-β (Aβ), the main culprit of Alzheimer's disease (AD). Alternatively, once AβPP undergoes clathrin-dependent endocytosis, it can be sequentially cleaved by β-secretase and γ-secretase at endosomes, producing Aβ (amyloidogenic pathway). β-N-acetylglucosamine (GlcNAc) can be attached to serine/threonine residues of the target proteins. This novel type of O-linked glycosylation is called O-GlcNAcylation mediated by O-GlcNAc transferase (OGT). The removal of GlcNAc is mediated by O-GlcNAcase (OGN). Recently, it is shown that O-GlcNAcylation of AβPP increases the non-amyloidogenic pathway. To investigate the regulatory role for O-GlcNAcylation in AβPP processing, we first tested the effects of inhibitor for OGN, PUGNAc, on AβPP metabolism in HeLa cells stably transfected with Swedish mutant form of AβPP. Increasing O-GlcNAcylated AβPP level increased α-secretase product while decreased β-secretase products. We found that PUGNAc increased the trafficking rate of AβPP from the trans-Golgi network to the plasma membrane, and selectively decreased the endocytosis rate of AβPP. These events may contribute to the increased AβPP level in the plasma membrane by PUGNAc. Inhibiting clathrin-dependent endocytosis prevented the effect of PUGNAc on Aβ, suggesting that the effect of PUGNAc was mainly mediated by decreasing AβPP endocytosis. These results strongly indicate that O-GlcNAcylation promotes the plasma membrane localization of AβPP, which enhances the non-amyloidogenic processing of AβPP. Thus, O-GlcNAcylation of AβPP can be a potential therapeutic strategy for AD.
Collapse
Affiliation(s)
- Yoon Sun Chun
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Yurim Park
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Hyun Geun Oh
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Tae-Wan Kim
- Department of Pathology and Cell Biology, and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Hyun Ok Yang
- Natural Products Research Center, Korea Institute of Science and Technology (KIST) Gangneung Institute, Gangneung, Gangwon-do, South Korea
| | - Myoung Kyu Park
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Sungkwon Chung
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, South Korea
| |
Collapse
|
15
|
Oh HG, Chun YS, Park CS, Kim TW, Park MK, Chung S. Regulation of basal autophagy by transient receptor potential melastatin 7 (TRPM7) channel. Biochem Biophys Res Commun 2015; 463:7-12. [DOI: 10.1016/j.bbrc.2015.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
|
16
|
Cho MK, Park MK, Kang SA, Park SK, Lyu JH, Kim DH, Park HK, Yu HS. TLR2-dependent amelioration of allergic airway inflammation by parasitic nematode type II MIF in mice. Parasite Immunol 2015; 37:180-91. [PMID: 25559209 DOI: 10.1111/pim.12172] [Citation(s) in RCA: 22] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 12/24/2014] [Indexed: 12/29/2022]
Abstract
In our previous studies, the recombinant type II macrophage migration inhibitory factor homologue (rAs-MIF) secreted from Anisakis simplex suppressed experimental inflammation mouse model through IL-10 production and CD4(+)CD25(+)Foxp3(+) T-cell recruitment. Also, TLR2 gene expression was significantly increased following rAs-MIF treatment. To know the relation between TLR2 and amelioration mechanisms of rAs-MIF, we induced allergic airway inflammation by ovalbumin and alum with or without rAs-MIF under TLR2 blocking systems [anti-TLR2-specific antibody (α-mTLR2 Ab) treatment and using TLR2 knockout mice]. As a result, the amelioration effects of rAs-MIF in allergic airway inflammation model (diminished inflammation and Th2 response in the lung, increased IL-10 secretion, CD4(+)CD25(+)Foxp3(+) T-cell recruitment) were diminished under two of the TLR2 blocking model. The expression of TLR2 on the surface of lung epithelial cell was significantly elevated by rAs-MIF treatment or Pam3CSK (TLR2-specific agonist) treatment, but they might have some competition effect on the elevation of TLR2 expression. In addition, the elevation of IL-10 gene expression by rAs-MIF treatment was significantly inhibited by α-mTLR2 Ab or Pam3CSK pretreatment. In conclusion, anti-inflammatory effects of the rAs-MIF on OVA-induced allergic airway inflammation might be closely related to TLR2.
Collapse
Affiliation(s)
- M K Cho
- Department of Parasitology, School of Medicine, Pusan National University, Yangsan-si, Korea
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Abstract
In this study, we reported two gram-negative bacteria that were isolated from bitterns, designated as SKKU-TP7(T) and SKKU-TP20, representing a novel species of Citrobacter. Based on the 16S rRNA gene sequences, the two strains were found to be closely related and showed the highest pairwise similarity with Citrobacter farmeri CDC 2992-81(T) (97.1-97.3 %) and other Citrobacter species. Cellular fatty acid analysis revealed that the profiles of strains SKKU-TP7(T) and SKKU-TP20 were similar to those of related species of Citrobacter. The major cellular fatty acids were C16:0 (31.5 %), summed feature 3 (C16:1 ω7c, C16:1 ω6c, 19.7 %), summed feature 8 (C18:1 ω7c, C18:1 ω6c, 11.9 %), C17:0 cyclo (10.7 %), and summed feature 2 (C12:0 aldehyde/unknown 10928, 9.5 %). Although the strains could utilize sucrose and raffinose as a carbon source, they did not produce ornithine decarboxylase and urease. The biochemical and genotypic characteristics indicate that strains SKKU-TP7(T) and SKKU-TP20 represent a novel species of Citrobacter, for which the name Citrobacter bitterns sp. nov. is proposed. The type strain is SKKU-TP7(T) (=KCTC 42139(T) = JCM 30009(T)).
Collapse
Affiliation(s)
- Kwan Soo Ko
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea,
| | | | | | | |
Collapse
|
18
|
Jang J, Um KB, Jang M, Kim SH, Cho H, Chung S, Kim HJ, Park MK. Balance between the proximal dendritic compartment and the soma determines spontaneous firing rate in midbrain dopamine neurons. J Physiol 2014; 592:2829-44. [PMID: 24756642 DOI: 10.1113/jphysiol.2014.275032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Midbrain dopamine (DA) neurons are slow intrinsic pacemakers that require the elaborate composition of many ion channels in the somatodendritic compartments. Understanding the major determinants of the spontaneous firing rate (SFR) of midbrain DA neurons is important because they determine the basal DA levels in target areas, including the striatum. As spontaneous firing occurs synchronously at the soma and dendrites, the electrical coupling between the soma and dendritic compartments has been regarded as a key determinant for the SFR. However, it is not known whether this somatodendritic coupling is served by the whole dendritic compartments or only parts of them. In the rat substantia nigra pars compacta (SNc) DA neurons, we demonstrate that the balance between the proximal dendritic compartment and the soma determines the SFR. Isolated SNc DA neurons showed a wide range of soma size and a variable number of primary dendrites but preserved a quite consistent SFR. The SFR was not correlated with soma size or with the number of primary dendrites, but it was strongly correlated with the area ratios of the proximal dendritic compartments to the somatic compartment. Tetrodotoxin puff and local Ca(2+) perturbation experiments, computer simulation, and local glutamate uncaging experiments suggest the importance of the proximal dendritic compartments in pacemaker activity. These data indicate that the proximal dendritic compartments, not the whole dendritic compartments, play a key role in the somatodendritic balance that determines the SFR in DA neurons.
Collapse
Affiliation(s)
- Jinyoung Jang
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Ki Bum Um
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Miae Jang
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Shin Hye Kim
- Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Hana Cho
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Sungkwon Chung
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Myoung Kyu Park
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| |
Collapse
|
19
|
Kim SH, Jang JY, Jang M, Um KB, Chung S, Kim HJ, Park MK. Homeostatic regulation mechanism of spontaneous firing determines glutamate responsiveness in the midbrain dopamine neurons. Cell Calcium 2013; 54:295-306. [PMID: 23988034 DOI: 10.1016/j.ceca.2013.07.004] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 07/23/2013] [Accepted: 07/28/2013] [Indexed: 01/31/2023]
Abstract
Autonomous tonic firing of the midbrain dopamine neuron is essential for maintenance of ambient dopamine level in the brain, in which intracellular Ca2+ concentration ([Ca2+]c) plays a complex but pivotal role. However, little is known about Ca2+ signals by which dopamine neurons maintain an optimum spontaneous firing rate. In the midbrain dopamine neurons, we here show that spontaneous firing evoked [Ca2+]c changes in a phasic manner in the dendritic region but a tonic manner in the soma. Tonic levels of somatic [Ca2+]c strictly tallied with spontaneous firing rates. However, manipulatory raising or lowering of [Ca2+]c with caged compounds from the resting firing state proportionally suppressed or raised spontaneous firing rate, respectively, suggesting presence of the homeostatic regulation mechanism for spontaneous firing rate via tonic [Ca2+]c changes of the soma. More importantly, abolition of this homeostatic regulation mechanism significantly exaggerated the responses of tonic firings and high-frequency phasic discharges to glutamate. Therefore, we conclude that this Ca(2+)-dependent homeostatic regulation mechanism is responsible for not only maintaining optimum rate of spontaneous firing, but also proper responses to glutamate. Perturbation of this mechanism could cause dopamine neurons to be more vulnerable to glutamate and Ca2+ toxicities.
Collapse
Affiliation(s)
- Shin Hye Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong, Jangan-ku, Suwon 440-746, Republic of Korea; Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon 440-746, Republic of Korea
| | | | | | | | | | | | | |
Collapse
|
20
|
Chun YS, Oh HG, Park MK, Cho H, Chung S. Cholesterol regulates HERG K+ channel activation by increasing phospholipase C β1 expression. Channels (Austin) 2013; 7:275-87. [PMID: 23793622 DOI: 10.4161/chan.25122] [Citation(s) in RCA: 5] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Human ether-a-go-go-related gene (HERG) K(+) channel underlies the rapidly activating delayed rectifier K(+) conductance (IKr) during normal cardiac repolarization. Also, it may regulate excitability in many neuronal cells. Recently, we showed that enrichment of cell membrane with cholesterol inhibits HERG channels by reducing the levels of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] due to the activation of phospholipase C (PLC). In this study, we further explored the effect of cholesterol enrichment on HERG channel kinetics. When membrane cholesterol level was mildly increased in human embryonic kidney (HEK) 293 cells expressing HERG channel, the inactivation and deactivation kinetics of HERG current were not affected, but the activation rate was significantly decelerated at all voltages tested. The application of PtdIns(4,5)P2 or inhibitor for PLC prevented the effect of cholesterol enrichment, while the presence of antibody against PtdIns(4,5)P2 in pipette solution mimicked the effect of cholesterol enrichment. These results indicate that the effect of cholesterol enrichment on HERG channel is due to the depletion of PtdIns(4,5)P2. We also found that cholesterol enrichment significantly increases the expression of β1 and β3 isoforms of PLC (PLCβ1, PLCβ3) in the membrane. Since the effects of cholesterol enrichment on HERG channel were prevented by inhibiting transcription or by inhibiting PLCβ1 expression, we conclude that increased PLCβ1 expression leads to the deceleration of HERG channel activation rate via downregulation of PtdIns(4,5)P2. These results confirm a crosstalk between two plasma membrane-enriched lipids, cholesterol and PtdIns(4,5)P2, in the regulation of HERG channels.
Collapse
Affiliation(s)
- Yoon Sun Chun
- Department of Physiology; Samsung Biomedical Research Institute; Sungkyunkwan University School of Medicine; Suwon, South Korea
| | | | | | | | | |
Collapse
|
21
|
Chun YS, Oh HG, Park MK, Kim TW, Chung S. Increasing Membrane Cholesterol Level Increases the Amyloidogenic Peptide by Enhancing the Expression of Phospholipase C. J Neurodegener Dis 2013; 2013:407903. [PMID: 26316988 PMCID: PMC4437359 DOI: 10.1155/2013/407903] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 12/09/2012] [Indexed: 11/24/2022]
Abstract
Cerebral elevation of 42-residue amyloid β-peptide (Aβ42) triggers neuronal dysfunction in Alzheimer's disease (AD). Even though a number of cholesterol modulating agents have been shown to affect Aβ generation, the role of cholesterol in the pathogenesis of AD is not clear yet. Recently, we have shown that increased membrane cholesterol levels downregulates phosphatidylinositol 4,5-bisphosphate (PIP2) via activation of phospholipase C (PLC). In this study, we tested whether membrane cholesterol levels may affect the Aβ42 production via changing PIP2 levels. Increasing membrane cholesterol levels decreased PIP2 and increased secreted Aβ42. Supplying PIP2, by using a PIP2-carrier system, blocked the effect of cholesterol on Aβ42. We also found that cholesterol increased the expressions of β1 and β3 PLC isoforms (PLCβ1, PLCβ3). Silencing the expression of PLCβ1 prevented the effects of cholesterol on PIP2 levels as well as on Aβ42 production, suggesting that increased membrane cholesterol levels increased secreted Aβ42 by downregulating PIP2 via enhancing the expression of PLCβ1. Thus, cholesterol metabolism may be linked to Aβ42 levels via PLCβ1 expression and subsequent changes in PIP2 metabolism.
Collapse
Affiliation(s)
- Yoon Sun Chun
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
| | - Hyun Geun Oh
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
| | - Myoung Kyu Park
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
| | - Tae-Wan Kim
- Department of Pathology, Columbia University Medical Center, New York, NY 10032, USA
| | - Sungkwon Chung
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
| |
Collapse
|
22
|
Oh HG, Chun YS, Kim Y, Youn SH, Shin S, Park MK, Kim TW, Chung S. Modulation of transient receptor potential melastatin related 7 channel by presenilins. Dev Neurobiol 2012; 72:865-77. [PMID: 22102510 DOI: 10.1002/dneu.22001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Presenilins (PS1 and PS2) are multifunctional proteins involved in a diverse array of molecular and cellular functions, including proteolysis, development, neurogenesis, synaptic plasticity, ion channel regulation and phospholipid metabolism. Mutations in presenilin genes are responsible for the majority of Familial Alzheimer disease (FAD). Consequently, FAD-associated mutations in genes encoding PS1 or PS2 lead to several key cellular phenotypes, including alterations in proteolysis of β-amyloid precursor protein (APP) and Ca(2+) entry. The mechanism underlying presenilin (PS)-mediated modulation of Ca(2+) entry remains to be determined. Our previous studies showed that the PS-dependent down-regulation of phosphatidylinositol-4,5-bisphosphate (PIP2) is attributable to the observed Ca(2+) deficits. In this study, we attempted to identify the ion channel that is subject to the PIP2 and PS-dependent modulation. We found that Ca(2+) or Zn(2+) entry via the transient receptor potential melastatin 7 (TRPM7) channel was attenuated by the presence of FAD-associated PS1 mutants, such as ΔE9 and L286V. TRPM7 has been implicated in Mg(2+) homeostasis and embryonic development. The intracellular delivery of PIP2 restored TRPM7-mediated Ca(2+) influx, indicating that the observed deficits in Ca(2+) entry are due to downregulation of PIP2. Conversely, PS1 and PS2 deficiency, previously shown to upregulate PIP2 levels, potentiated TRPM7-mediated Ca(2+) influx. PS-dependent changes in Ca(2+) influx could be neutralized by a TRPM7 channel blocker. Collectively, these results indicate that TRPM7 may underlie the Ca(2+) entry deficits observed in FAD-associated PS mutants and suggest that the normal function of PS involves regulation of TRPM7 through a PIP2-dependent mechanism.
Collapse
Affiliation(s)
- Hyun Geun Oh
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, South Korea
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Lee WR, Kim HS, Park MK, Lee JH, Kim KH. Synchronized operation by field programmable gate array based signal controller for the Thomson scattering diagnostic system in KSTAR. Rev Sci Instrum 2012; 83:093505. [PMID: 23020374 DOI: 10.1063/1.4752408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The Thomson scattering diagnostic system is successfully installed in the Korea Superconducting Tokamak Advanced Research (KSTAR) facility. We got the electron temperature and electron density data for the first time in 2011, 4th campaign using a field programmable gate array (FPGA) based signal control board. It operates as a signal generator, a detector, a controller, and a time measuring device. This board produces two configurable trigger pulses to operate Nd:YAG laser system and receives a laser beam detection signal from a photodiode detector. It allows a trigger pulse to be delivered to a time delay module to make a scattered signal measurement, measuring an asynchronous time value between the KSTAR timing board and the laser system injection signal. All functions are controlled by the embedded processor running on operating system within a single FPGA. It provides Ethernet communication interface and is configured with standard middleware to integrate with KSTAR. This controller has operated for two experimental campaigns including commissioning and performed the reconfiguration of logic designs to accommodate varying experimental situation without hardware rebuilding.
Collapse
Affiliation(s)
- W R Lee
- National Fusion Research Institute, Gwahangno 113, Daejeon 305-333, South Korea
| | | | | | | | | |
Collapse
|
24
|
Jang M, Jang JY, Kim SH, Uhm KB, Kang YK, Kim HJ, Chung S, Park MK. Functional organization of dendritic Ca2+ signals in midbrain dopamine neurons. Cell Calcium 2011; 50:370-80. [PMID: 21757230 DOI: 10.1016/j.ceca.2011.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/16/2011] [Accepted: 06/18/2011] [Indexed: 01/30/2023]
Abstract
Dendritic Ca2+ plays an important role not only in synaptic integration and synaptic plasticity, but also in dendritic excitability in midbrain dopamine neurons. However, the functional organization of dendritic Ca2+ signals in the dopamine neurons remains largely unknown. We therefore investigated dendritic Ca2+ signals by measuring glutamate-induced Ca2+ increases along the dendrites of acutely isolated midbrain dopamine neurons. Maximal doses of glutamate induced a [Ca2+]c rise with similar amplitudes in proximal and distal dendritic regions of a dopamine neuron. Glutamate receptors contributed incrementally to the [Ca2+]c rise according to their distance from the soma, with a reciprocal decrement in the contribution of voltage-operated Ca2+ channels (VOCCs). The contribution of AMPA and NMDA receptors increased with dendritic length, but that of metabotropic glutamate receptors decreased. At low doses of glutamate at which spontaneous firing was sustained, the [Ca2+]c rise was higher in the distal than the proximal regions of a dendrite, possibly due to the increased spontaneous firing rate. These results indicate that functional organization of Ca2+ signals in the dendrites of dopamine neurons requires different combination of VOCCs and glutamate receptors according to dendritic length, and that regional Ca2+ rises in dendrites respond differently to applied glutamate concentration.
Collapse
Affiliation(s)
- Miae Jang
- Department of Physiology, Sungkyunkwan University School of Medicine, and Department of Pathology, Inje University Seoul Paik Hospital, 300 Chunchun-dong, Jangan-ku, Suwon 440-746, Republic of Korea
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Chung S, Chun YS, Park MK. Enhanced expression of phospholipase C by cholesterol increases the production of amyloidogenic peptide. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1001.5] [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)
- Sungkwon Chung
- PhysiologySungkyunkwan University School of MedicineSuwonRepublic of Korea
| | - Yoon Sun Chun
- PhysiologySungkyunkwan University School of MedicineSuwonRepublic of Korea
| | - Myoung Kyu Park
- PhysiologySungkyunkwan University School of MedicineSuwonRepublic of Korea
| |
Collapse
|
26
|
Jang JY, Jang M, Kim SH, Um KB, Kang YK, Kim HJ, Chung S, Park MK. Regulation of dopaminergic neuron firing by heterogeneous dopamine autoreceptors in the substantia nigra pars compacta. J Neurochem 2011; 116:966-74. [PMID: 21073466 DOI: 10.1111/j.1471-4159.2010.07107.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dopamine (DA) receptors generate many cellular signals and play various roles in locomotion, motivation, hormone production, and drug abuse. According to the location and expression types of the receptors in the brain, DA signals act in either stimulatory or inhibitory manners. Although DA autoreceptors in the substantia nigra pars compacta are known to regulate firing activity, the exact expression patterns and roles of DA autoreceptor types on the firing activity are highly debated. Therefore, we performed individual correlation studies between firing activity and receptor expression patterns using acutely isolated rat substantia nigra pars compacta DA neurons. When we performed single-cell RT-PCR experiments, D(1), D(2)S, D(2)L, D(3), and D(5) receptor mRNA were heterogeneously expressed in the order of D(2)L > D(2)S > D(3) > D(5) > D(1). Stimulation of D(2) receptors with quinpirole suppressed spontaneous firing similarly among all neurons expressing mRNA solely for D(2)S, D(2)L, or D(3) receptors. However, quinpirole most strongly suppressed spontaneous firing in the neurons expressing mRNA for both D(2) and D(3) receptors. These data suggest that D(2) S, D(2)L, and D(3) receptors are able to equally suppress firing activity, but that D(2) and D(3) receptors synergistically suppress firing. This diversity in DA autoreceptors could explain the various actions of DA in the brain.
Collapse
Affiliation(s)
- Jin Young Jang
- Department of Physiology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Jangan-ku, Suwon, Korea
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Kim Y, Park MK, Chung S. Protective effect of urocortin on 1-methyl-4-phenylpyridinium-induced dopaminergic neuronal death. Mol Cells 2010; 30:427-33. [PMID: 20821057 DOI: 10.1007/s10059-010-0132-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 07/29/2010] [Accepted: 08/02/2010] [Indexed: 10/19/2022] Open
Abstract
Recent studies have indicated that the corticotropin releasing hormone (CRF)-related peptide, urocortin, restores key indicators of damage in animal models for Parkinson's disease (PD). However, the molecular mechanism for the neuroprotective effect of urocortin is unknown. 1-Methy-4-phenylpyridinium (MPP(+)) induces dopaminergic neuronal death. In the present study, MPP(+)-induced neuroblastoma SH-SY5Y cell death was significantly attenuated by urocortin in a concentration-dependent manner. The protective effect of urocortin involved the activation of CRF receptor type 1, resulting in the increase of cyclic AMP (cAMP) levels. Various cAMP-enhancing reagents mimicked the effect of urocortin, while inhibitors for protein kinase A (PKA) blocked the effect of urocortin, strongly implicating the involvement of cAMP-PKA pathway in the neuroprotective effect of urocortin on MPP(+)-induced cell death. As the downstream of this signal pathway, urocortin promoted phosphorylation of both glycogen synthase kinase 3β and extracellular signal-regulated kinases, which are known to promote cell survival. These neuroprotective signaling pathways of urocortin may serve as potential therapeutic targets for PD.
Collapse
Affiliation(s)
- Yonjung Kim
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, 440-746, Korea
| | | | | |
Collapse
|
28
|
Lee SY, Choi HK, Kim ST, Chung S, Park MK, Cho JH, Ho WK, Cho H. Cholesterol inhibits M-type K+ channels via protein kinase C-dependent phosphorylation in sympathetic neurons. J Biol Chem 2010; 285:10939-50. [PMID: 20123983 PMCID: PMC2856299 DOI: 10.1074/jbc.m109.048868] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [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: 07/27/2009] [Revised: 01/25/2010] [Indexed: 01/10/2023] Open
Abstract
M-type (KCNQ) potassium channels play an important role in regulating the action potential firing in neurons. Here, we investigated the effect of cholesterol on M current in superior cervical ganglion (SCG) sympathetic neurons, using the patch clamp technique. M current was inhibited in a dose-dependent manner by cholesterol loading with a methyl-beta-cyclodextrin-cholesterol complex. This effect was prevented when membrane cholesterol level was restored by including empty methyl-beta-cyclodextrin in the pipette solution. Dialysis of cells with AMP-PNP instead of ATP prevented cholesterol action on M currents. Protein kinase C (PKC) inhibitor, calphostin C, abolished cholesterol-induced inhibition whereas the PKC activator, PDBu, mimicked the inhibition of M currents by cholesterol. The in vitro kinase assay showed that KCNQ2 subunits of M channel can be phosphorylated by PKC. A KCNQ2 mutant that is defective in phosphorylation by PKC failed to show current inhibition not only by PDBu but also by cholesterol. These results indicate that cholesterol-induced inhibition of M currents is mediated by PKC phosphorylation. The inhibition of M currents by PDBu and cholesterol was completely blocked by PIP(2) loading, indicating that the decrease in PIP(2)-channel interaction underlies M channel inhibition by PKC-mediated phosphorylation. We conclude that cholesterol specifically regulates M currents in SCG neurons via PKC activation.
Collapse
Affiliation(s)
| | - Hyun-Kyung Choi
- Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea and
| | - Seong-Tae Kim
- Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea and
| | | | | | - Jung-Hwa Cho
- the WCU Neurocytomics Program Project, Department of Physiology, Seoul National University College of Medicine and Neuroscience Research Institute, Seoul 110-799, Korea
| | - Won-Kyung Ho
- the WCU Neurocytomics Program Project, Department of Physiology, Seoul National University College of Medicine and Neuroscience Research Institute, Seoul 110-799, Korea
| | - Hana Cho
- From the Departments of Physiology and
| |
Collapse
|
29
|
Chun YS, Shin S, Kim Y, Cho H, Park MK, Kim TW, Voronov SV, Di Paolo G, Suh BC, Chung S. Cholesterol modulates ion channels via down-regulation of phosphatidylinositol 4,5-bisphosphate. J Neurochem 2009; 112:1286-94. [PMID: 20015154 DOI: 10.1111/j.1471-4159.2009.06545.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ubiquitously expressed Mg(2+)-inhibitory cation (MIC) channels are permeable to Ca2+ and Mg2+ and are essential for cell viability. When membrane cholesterol level was increased by pre-incubating cells with a water-soluble form of cholesterol, the endogenous MIC current in HEK293 cells was negatively regulated. The application of phosphatidylinositol 4,5-bisphosphate (PIP2) recovered MIC current from cholesterol effect. As PIP2 is the direct modulator for MIC channels, high cholesterol content may cause down-regulation of PIP2. To test this possibility, we examined the effect of cholesterol on two exogenously expressed PIP2-sensitive K+ channels: human Ether-a-go-go related gene (HERG) and KCNQ. Enrichment with cholesterol inhibited HERG currents, while inclusion of PIP2 in the pipette solution blocked the cholesterol effect. KCNQ channel was also inhibited by cholesterol. The effects of cholesterol on these channels were blocked by pre-incubating cells with inhibitors for phospholipase C, which may indicate that cholesterol enrichment induces the depletion of PIP2 via phospholipase C activation. Lipid analysis showed that cholesterol enrichment reduced gamma-(32)P incorporation into PIP2 by approximately 35%. Our results suggest that cholesterol may modulate ion channels by changing the levels of PIP2. Thus, an important cross-talk exists among two plasma membrane-enriched lipids, cholesterol and PIP2.
Collapse
Affiliation(s)
- Yoon Sun Chun
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Kim Y, Park MK, Chung S. Regulation of somatodendritic dopamine release by corticotropin-releasing factor via the inhibition of voltage-operated Ca2+ channels. Neurosci Lett 2009; 465:31-5. [DOI: 10.1016/j.neulet.2009.08.066] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 08/21/2009] [Accepted: 08/28/2009] [Indexed: 10/20/2022]
|
31
|
Park MK, Fontana, Babaali H, Gilbert-McClain LI, Stylianou M, Joo J, Moss J, Manganiello VC. Steroid-sparing effects of pentoxifylline in pulmonary sarcoidosis. Sarcoidosis Vasc Diffuse Lung Dis 2009; 26:121-31. [PMID: 20560292 PMCID: PMC2946799] [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] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
BACKGROUND Agents that target pro-inflammatory cytokines may be useful in pulmonary sarcoidosis. OBJECTIVE To determine effectiveness of a non-selective cyclic nucleotide phosphodiesterase (PDE) inhibitor, pentoxifylline (POF). DESIGN Randomized, double-blind, placebo-controlled trial, SETTING Clinical Research Center, National Institutes of Health. PATIENTS 27 patients with biopsy-confirmed pulmonary sarcoidosis receiving prednisone. INTERVENTION Placebo or POF (1200-2000 mg/day) for 10 months, as prednisone was tapered. MEASUREMENTS Primary endpoints: sustained improvement in two or more pulmonary function parameters, or a combination of one pulmonary function parameter and dyspnea. RESULTS Except for one patient, primary endpoints were not reached in POF-treated patients. Therefore, a post hoc analysis was performed. The observed relative risk reduction for flares associated with POF treatment was 54.9% (95% CI 0.21, 0.89) and the absolute risk reduction was 50.6% (95% CI 0.22, 0.80). Compared to placebo treatment, in the POF group, the mean prednisone dose was lower at 8 and 10 months (p = 0.007 and 0.01 respectively), and there was a trend towards less prednisone usage over the entire study period (p = 0.053), as determined by cumulative change analysis. CONCLUSIONS Although our exploratory post hoc analysis suggested that POF reduced flares and had steroid-sparing effects, given the study limitations, definitive conclusions cannot be drawn regarding the efficacy of POF in pulmonary sarcoidosis. In addition, gastrointestinal side-effects, at the doses used, would seem to limit the use of POF in treating pulmonary sarcoidosis. Overall, however, this trial may provide a basis for using more specific, better-tolerated, PDE inhibitors in future clinical trials.
Collapse
Affiliation(s)
- M K Park
- Translational Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1434, USA
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Choi YM, Jang JY, Jang M, Kim SH, Kang YK, Cho H, Chung S, Park MK. Modulation of firing activity by ATP in dopamine neurons of the rat substantia nigra pars compacta. Neuroscience 2009; 160:587-95. [PMID: 19272429 DOI: 10.1016/j.neuroscience.2009.02.067] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2008] [Revised: 02/12/2009] [Accepted: 02/27/2009] [Indexed: 11/26/2022]
Abstract
ATP acts as a neurotransmitter or co-neurotransmitter in many areas of the CNS and peripheral nervous systems; however, little is known about the expression and functional role of purinoceptors (P2) in midbrain dopaminergic neurons. Therefore, we investigated P2X receptor expression and regulation of spontaneous firing activity in dopaminergic neurons of the substantia nigra pars compacta (SNc) in rats using patch-clamp and Ca(2+)-imaging techniques. In most neurons, application of ATP (1 microM-1 mM) increased firing rate dose-dependently (EC(50)=1.26+/-0.26 microM, n=45). When the P2-receptor agonists such as 2-methylthio-adenosine 5'-triphosphate (2-MeSATP) or ATPgammaS were applied or pressure-applied to the neuron, the firing activity increased together with a rise in cytosolic Ca(2+) concentration ([Ca(2+)]c), but application of beta,gamma-methylene ATP (P2X(1, 3) agonist) or methylthio-adenosine 5'-diphosphate (P2Y(1) agonist) had no effect. In many neurons, the effect of ATP was abolished by the application of the P2-receptor antagonists, suramin or pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). When ATP was applied in a Ca(2+)-free solution, there was no detectable change in [Ca(2+)]c, suggesting that ATP does not release Ca(2+) from intracellular stores. In the single-cell reverse transcription polymerase chain reaction (RT-PCR), we found that 65% of dopaminergic neurons expressed mRNAs for P2X receptors; positive amplifications of P2X(6) (57.1%), P2X(2/6) (25.0%), and P2X(4) mRNA (17.9%), respectively. From the above results, we could conclude that ATP modulates firing activities in the rat SNc dopaminergic neurons, possibly via P2X(2), P2X(2/6), and/or P2X(4) receptors.
Collapse
Affiliation(s)
- Y M Choi
- Department of Physiology, Sungkyunkwan University, School of Medicine and Center for Molecular Medicine, Samsung Biomedical Research Institute, Suwon, Korea
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Kim Y, Park MK, Chung S. Corticotropin-releasing Factor Regulates Somatodendritic Dopamine Release By Inhibiting Voltage-dependent Ca2+ Channels. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.873] [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: 11/28/2022] Open
|
34
|
Jin TE, Jang M, Kim H, Choi YM, Cho H, Chung S, Park MK. Involvement of corticotropin-releasing factor receptor 2 beta in differentiation of dopaminergic MN9D cells. Mol Cells 2008; 26:243-9. [PMID: 18511879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
Corticotropin releasing factor (CRF) mediates various responses to stress through CRF receptors 1 and 2. CRF receptor 2 has two forms, 2alpha and 2beta each of which appears to have distinct roles. Here we used dopaminergic neuron-derived MN9D cells to investigate the function of CRF receptor 2 in dopamine neurons. We found that n-butyrate, a histone deacetylase inhibitor, induced MN9D cell differentiation and increased gene expression of all CRF receptors. CRF receptor 2beta was minimally expressed in MN9D cells; however, its expression dramatically increased during differentiation. CRF receptor 2beta expression levels appeared to correlate with neurite outgrowth, suggesting CRF receptor 2beta involvement in neuronal differentiation. To validate this statement, we made a CRF receptor 2beta-overexpressing MN9D/CRFR2 beta stable cell line. This cell line showed robust neurite outgrowth and GAP43 overexpression, together with MEK and ERK activation, suggesting MN9D cell neuronal differentiation. From these results, we conclude that CRF receptor 2beta plays an important role in MN9D cell differentiation by activating the MEK/ERK signaling pathway.
Collapse
Affiliation(s)
- Tae-Eun Jin
- Department of Physiology, Sungkyunkwan University, School of Medicine and Center For Molecular Medicine, Samsung Biomedical Research Institute, Suwon 440-746, Korea
| | | | | | | | | | | | | |
Collapse
|
35
|
Kim Y, Park MK, Chung S. Voltage-operated Ca2+ channels regulate dopamine release from somata of dopamine neurons in the substantia nigra pars compacta. Biochem Biophys Res Commun 2008; 373:665-9. [PMID: 18601902 DOI: 10.1016/j.bbrc.2008.06.099] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 06/24/2008] [Indexed: 10/21/2022]
Abstract
Dopamine (DA) neurons release DA not only from axon terminals at the striatum, but from their somata and dendrites at the substantia nigra pars compacta (SNc). Released DA may auto-regulate further DA release or modulate non-DA cells. However, the actual mechanism of somatodendritic DA release, especially the Ca(2+) dependency of the process, remains controversial. In this study, we used amperometry to monitor DA release from somata of acutely isolated rat DA neurons. We found that DA neurons spontaneously released DA in the resting state. Removal of extracellular Ca(2+) and application of blockers for voltage-operated Ca(2+) channels (VOCCs) suppressed the frequency of secretion events. Activation of VOCCs by stimulation with K(+)-rich saline increased the frequency of secretion events, which were also sensitive to blockers for L- and T-type Ca(2+) channels. These results suggest that Ca(2+) influx through VOCCs regulates DA release from somata of DA neurons.
Collapse
Affiliation(s)
- Yonjung Kim
- Department of Physiology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Jangan-ku, Suwon 440-746, South Korea
| | | | | |
Collapse
|
36
|
Abstract
Dendrites are integrating elements that receive numerous subsets of heterogeneous synaptic inputs, which generate temporally and spatially distinct changes in membrane potential and intracellular Ca2+ levels in local domains. The ubiquitously distributed endoplasmic reticulum (ER) in dendrites is luminally connected to the bulk ER in the soma, constituting a huge interconnected intracellular network that allows rapid Ca2+ diffusion and equilibration. The ER is an excitable organelle that can elicit or terminate cytosolic Ca2+ signals in local or global domains. The absolute level or changes in the Ca2+ concentration in the ER lumen are also very important for the synthesis and maturation of proteins, regulation of gene expression, mitochondrial functions, neuronal excitability, and synaptic plasticity. Through the connected lumen of the ER, information from multiple dendritic events in neurons appears to be delivered into the bulk ER in the soma. Therefore, the ER network in neurons is emerging as a conveyor and integrator of signals. In this article, we will discuss the various roles of the ER and the functional and structural organization of the ER network in neurons. NEUROSCIENTIST 14(1):68—77, 2008.
Collapse
Affiliation(s)
- Myoung Kyu Park
- Department of Physiliogy, Sungkyunkwan University School of Medicine and Center for Molecular Medicine, Samsung Biomedical Resarch Institute, Suwon, Korea.
| | | | | | | |
Collapse
|
37
|
Kim Y, Park MK, Uhm DY, Chung S. Modulation of T-type Ca2+ channels by corticotropin-releasing factor through protein kinase C pathway in MN9D dopaminergic cells. Biochem Biophys Res Commun 2007; 358:796-801. [PMID: 17506983 DOI: 10.1016/j.bbrc.2007.04.198] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Accepted: 04/27/2007] [Indexed: 11/21/2022]
Abstract
Corticotrophin-releasing factor (CRF) is the main regulator of the body's stress axis and its signal is translated through G-protein-coupled CRF receptors (CRF-R1, CRF-R2). Even though CRF receptors are present in the midbrain dopamine neurons, the cellular mechanism of CRF action is not clear yet. Since voltage-dependent Ca(2+) channels are highly expressed and important in dopamine neuronal functions, we tested the effect of CRF on voltage-dependent Ca(2+) channels in MN9D cells, a model of dopamine neurons. The application of CRF-related peptide, urocortin 1, reversibly inhibited T-type Ca(2+) currents, which was a major Ca(2+) channel in the cells. The effect of urocortin was abolished by specific CRF-R1 antagonist and was mimicked by protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate. PKC inhibitors abolished the effect of urocortin. These results suggest that urocortin modulates T-type Ca(2+) channel by interacting with CRF-R1 via the activation of PKC signal pathway in MN9D cells.
Collapse
Affiliation(s)
- Yonjung Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 440-746, South Korea
| | | | | | | |
Collapse
|
38
|
Hajdú P, Ikemoto T, Akazome Y, Park MK, Oka Y. Terminal nerve gonadotrophin-releasing hormone (GnRH) neurones express multiple GnRH receptors in a teleost, the dwarf gourami (Colisa lalia). J Neuroendocrinol 2007; 19:475-9. [PMID: 17504441 DOI: 10.1111/j.1365-2826.2007.01553.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gonadotophin-releasing hormone (GnRH) peptide released from the terminal nerve (TN)-GnRH neurones of the dwarf gourami primarily modifies the electrical properties of various neurones, including the TN-GnRH neurones themselves. However, our knowledge on the expression of GnRH receptors (GnRHRs) in the TN-GnRH neurones is still limited. Here, we used the single-cell reverse transcriptase-polymerase chain reaction after whole-cell patch-clamp recording to study the distribution of various GnRHR types expressed in the individual TN-GnRH neurones. We found that TN-GnRH neurones express two of the three types of GnRHRs cloned in the dwarf gourami: GnRHR1-2 and -R2, but not -R1-1. Furthermore, in agreement with our previous findings, all TN-GnRH neurones contained mRNAs of salmon GnRH but not chicken GnRH-II.
Collapse
Affiliation(s)
- P Hajdú
- Laboratory of Biological Signalling, Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | | | | | | | | |
Collapse
|
39
|
Kim SH, Choi YM, Jang JY, Chung S, Kang YK, Park MK. Nonselective cation channels are essential for maintaining intracellular Ca2+ levels and spontaneous firing activity in the midbrain dopamine neurons. Pflugers Arch 2007; 455:309-21. [PMID: 17492308 DOI: 10.1007/s00424-007-0279-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 04/01/2007] [Indexed: 02/06/2023]
Abstract
Intracellular Ca2+ and Ca2+-permeable ion channels are important in regulating the firing activity and pattern of midbrain dopamine neurons, but the role of Ca2+-permeable nonselective cation channels (NSCCs) on spontaneous firing activity is unclear. Therefore, we investigated how Ca2+-permeable NSCCs modulate spontaneous firing activity and cytosolic Ca2+ concentration ([Ca2+]c) in acutely isolated midbrain dopamine neurons of the rat. Applications of voltage-dependent Ca2+ channels antagonists failed to abolish spontaneous firing activity completely, but they decreased firing rate and [Ca2+]c. However, a blockade of NSCCs by 2-APB or SKF96365 more potently suppressed spontaneous firings with a depolarization of membrane potential and strong decreases in basal [Ca2+]c levels. The depolarization of membrane potentials was attenuated by intracellular dialysis with 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). NSCCs blockers inhibited oscillatory potentials and decreased basal [Ca2+]c in the presence of tetrodotoxin. Apamin, a small-conductance Ca2+-activated K+ channel inhibitor, depolarized membrane potentials and enhanced firing rates. From these data, we conclude that NSCCs not only make up the tonic Ca2+ entry pathways to uphold basal [Ca2+]c levels but also contribute to generation of spontaneous firings, thereby regulating spontaneous firing activities of the midbrain dopamine neurons.
Collapse
Affiliation(s)
- Shin Hye Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, 300 Chunchun-dong Jangan-ku, Suwon 440-746, Republic of Korea
| | | | | | | | | | | |
Collapse
|
40
|
Ahn Y, Kwon E, Shim JE, Park MK, Joo Y, Kimm K, Park C, Kim DH. Validation and reproducibility of food frequency questionnaire for Korean genome epidemiologic study. Eur J Clin Nutr 2007; 61:1435-41. [PMID: 17299477 DOI: 10.1038/sj.ejcn.1602657] [Citation(s) in RCA: 565] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE To evaluate validity and reliability of the food-frequency questionnaire (FFQ) developed for the Korean Genome Epidemiologic Study (KoGES). METHODS FFQ was administered twice at 1-year interval (first FFQ (FFQ1) at the beginning and second FFQ (FFQ2) at the end of the study) and diet records (DRs) were collected for 3 days during each of the four seasons from December 2002 to May 2004 for those who attended the health examination center. At the end of the study period, we collected the 12-day DRs of 124 participants. The nutrient intakes from the DRs were compared with both FFQ1 and FFQ2. RESULTS The intakes of energy and some nutrients estimated from FFQ1 and FFQ2 were different from those assessed by the DRs. Especially, the consumption of carbohydrates was higher in FFQ1 and FFQ2 than in the DRs. The de-attenuated, age, sex and energy intake adjusted correlation coefficients between the FFQ2 and the 12-day DRs in Korean population ranged between 0.23 (Vitamin A) and 0.64 (carbohydrate). The median for all nutrients was 0.39. The correlations were similar when we compared nutrient densities of both methods. Joint classification of calorie-adjusted nutrient intakes assessed by FFQ2 and 12-day DRs by quartile ranged from 25.8% (vitamin A) to 39.5% (carbohydrate, iron) for exact concordance. Except vitamin A, the proportion of subjects classified into distant quartile was less than 7% in all nutrients. The median of correlations between the two FFQs 1 year apart were 0.45 for all nutrient intakes and 0.39 for nutrient densities. CONCLUSIONS We conclude that the FFQ we have developed appears to be an acceptable tool for assessing the nutrient intakes in this population. Further studies for calibration of the FFQ collected from multicenters participating in the KoGES are needed. SPONSORSHIP This study was supported by the budget of the National Genome Research Institute, Korea National Institute of Health (2002-347-6111-221).
Collapse
Affiliation(s)
- Y Ahn
- Center for Genomic Science, National Institute of Health, Center for Disease Control and Prevention, Seoul, Korea
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Choi YM, Kim SH, Chung S, Uhm DY, Park MK. Regional interaction of endoplasmic reticulum Ca2+ signals between soma and dendrites through rapid luminal Ca2+ diffusion. J Neurosci 2006; 26:12127-36. [PMID: 17122037 PMCID: PMC6675421 DOI: 10.1523/jneurosci.3158-06.2006] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The endoplasmic reticulum (ER) Ca2+ store plays a key role in integration and conveyance of Ca2+ signals in highly polarized neurons. The interconnected ER network in neurons generates Ca2+ signals in local domains, but the regional interaction is unclear. Here, we show that continuous or repetitive applications of caffeine produced robust Ca2+ release from the ER Ca2+ store in dendritic areas without severe store depletion, but that similar stimuli applied to soma caused rapid store depletion in acutely isolated midbrain dopamine neurons. Partial emptying of the ER Ca2+ store within a dendrite caused a similar level of store depletion in unstimulated dendrites, as well as in soma. Photobleaching and local stimulation experiments revealed that Ca2+ and the dye trapped within the ER diffused rapidly from the soma to dendrites up to 90 microm, which we could resolve, suggesting that the ER network acts as a functional tunnel for rapid Ca2+ transport. These data imply that the ER in soma acts as a Ca2+ reservoir supplying Ca2+ to the dendritic store, and that the dendritic store, hence, is able to respond to Ca2+-mobilizing input signals endurably.
Collapse
Affiliation(s)
- Yu Mi Choi
- Department of Physiology, Sungkyunkwan University School of Medicine and Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Shin Hye Kim
- Department of Physiology, Sungkyunkwan University School of Medicine and Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Sungkwon Chung
- Department of Physiology, Sungkyunkwan University School of Medicine and Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Dae Yong Uhm
- Department of Physiology, Sungkyunkwan University School of Medicine and Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| | - Myoung Kyu Park
- Department of Physiology, Sungkyunkwan University School of Medicine and Center For Molecular Medicine, Samsung Biomedical Research Institute, 300 Chunchun-dong, Jangan-ku, Suwon, 440-746, Korea
| |
Collapse
|
42
|
Min JY, Park MH, Park MK, Park KW, Lee NW, Kim T, Kim HJ, Lee DH. Staurosporin induces neurite outgrowth through ROS generation in HN33 hippocampal cell lines. J Neural Transm (Vienna) 2006; 113:1821-6. [PMID: 16715208 DOI: 10.1007/s00702-006-0500-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Accepted: 03/17/2006] [Indexed: 11/29/2022]
Abstract
Staurosporin, a specific inhibitor of PKC, is widely used in studies of signal transduction pathways. Previous studies have shown that staurosporin induces neurite outgrowth, but the underlying mechanisms remain unclear. Here we report that staurosporin induces neurite outgrowth in HN33 hippocampal cells. Two other PKC inhibitors, Go 6976 (specific for alpha- and beta-isoforms) and rotterlin (a selective inhibitor of PKC delta), have no neuritogenic effect. In addition, staurosporin specifically increases ROS generation. NAC, which inhibits the generation of ROS, suppresses the staurosporin-induced neurite outgrowth in HN33 cells. Further, H(2)O(2) causes neurite outgrowth. Taken together, these results confirm a neuritogenic effect of staurosporin and point to ROS as the signal mediator of staurosporin-induced neurite outgrowth in HN33 hippocampal cells. Theme: Development and regeneration Topic: Neurotrophic factors: receptors and cellular mechanisms.
Collapse
Affiliation(s)
- J Y Min
- Department of Obstetrics and Gynecology, Korea University Medical College, 516 Gojan-1-dong, Danwon-gu, Ansan-si, Gyeonggi-do, Republic of Korea
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Bae JT, Park JP, Song CH, Yu CB, Park MK, Yun JW. Effect of carbon source on the mycelial growth and exo-biopolymer production by submerged culture of Paecilomyces japonica. J Biosci Bioeng 2005; 91:522-4. [PMID: 16233033 DOI: 10.1263/jbb.91.522] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2000] [Accepted: 02/02/2001] [Indexed: 11/17/2022]
Abstract
A significant difference was observed in the production pattern of exo-biopolymer and broth rheology during submerged culture of Paecilomyces japonica when two efficient carbon sources (maltose and sucrose) were employed. The maximum concentration of biopolymers in maltose medium (30 g/l) was higher than that in sucrose medium (25 g/l), whereas maximum mycelial concentration displayed an inverse result (i.e., 25 g/l in sucrose medium and 20 g/l in maltose medium). The broth rheology and morphology of P. japonica were also markedly different between the two culture media.
Collapse
Affiliation(s)
- J T Bae
- Department of Biotechnology, Taegu University, Kyungbuk 712-714, Korea
| | | | | | | | | | | |
Collapse
|
44
|
Ikemoto T, Park MK. Identification and molecular characterization of three GnRH ligands and five GnRH receptors in the spotted green pufferfish. Mol Cell Endocrinol 2005; 242:67-79. [PMID: 16122867 DOI: 10.1016/j.mce.2005.07.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [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] [Received: 05/09/2005] [Revised: 07/18/2005] [Accepted: 07/21/2005] [Indexed: 02/03/2023]
Abstract
Gonadotropin-releasing hormone (GnRH) is thought to have diverse physiological functions. Understanding regulatory mechanisms of GnRH functions requires detailed knowledge of gene expressions of both GnRH ligands and receptors in a single species. This report concerns identification and molecular characterization of GnRH ligands and receptors in the spotted green pufferfish Tetraodon nigroviridis. It was identified that the pufferfish possessed three types of GnRH ligands and five types of GnRH receptors. All types of ligands and receptors showed different expression patterns, and were widely expressed both inside and outside the brain. Gonads expressed all the ligand and receptor subtypes. Two of five receptor subtypes could not be detected in the pituitary gland of reproductively active individuals, suggesting the existence of novel GnRH systems independent of hypothalamic-pituitary-gonadal axis. Alternative splicing was also observed for some receptor subtypes. The present results indicate that diversified gene expressions combined with molecular diversity contribute to the functional diversity of GnRH.
Collapse
Affiliation(s)
- T Ikemoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | | |
Collapse
|
45
|
Lee M, Chung S, Uhm DY, Park MK. Regulation of zymogen granule exocytosis by Ca2+, cAMP, and PKC in pancreatic acinar cells. Biochem Biophys Res Commun 2005; 334:1241-7. [PMID: 16040001 DOI: 10.1016/j.bbrc.2005.07.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Accepted: 07/01/2005] [Indexed: 11/18/2022]
Abstract
The effect of cAMP and PKC on zymogen granule exocytosis was investigated by simultaneously measuring cytosolic Ca2+ concentration ([Ca2+]c) and individual zymogen granule exocytosis in isolated mouse pancreatic acini. When acinar cells were stimulated with acetylcholine (ACh, 10 microM), exocytic events were detected through granule-attached apical membranes with [Ca2+]c rise. Application of secretin, forskolin (an adenylate cyclase activator), or PMA (a PKC activator) alone did not elicit any [Ca2+]c rise or zymogen granule exocytosis, but co-stimulation with ACh led to exocytosis in that the total number of secreted granules increased markedly without a significant difference in [Ca2+]c rises. When we evoked exocytosis by [Ca2+]c ramps, pretreatment with forskolin or PMA elicited exocytosis at lower [Ca2+]c levels. These results indicate that PKC or cAMP alone could not directly elicit zymogen granule exocytosis, but that they increase the total releasable pool by rendering zymogen granules more sensitive to Ca2+.
Collapse
Affiliation(s)
- Misun Lee
- Department of Physiology, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, 300 Chunchun-dong Jangan-ku, Suwon 440-746, Republic of Korea
| | | | | | | |
Collapse
|
46
|
Abstract
We previously reported blood pressure (BP) readings obtained by the Dinamap (DIN) (Model 8100) were 10 mmHg higher than those obtained by auscultatory methods and thus were not interchangeable. DIN BP data on 7208 schoolchildren ages 5 to 17 were analyzed to generate normative DIN BP standards and to examine the rational for presenting BP standards according to age and height percentiles. Three BP measurements were taken in the sitting position using a BP cuff width 40% to 50% of the circumference of the arm. Boys' systolic pressures (SP) were significantly (p < 0.05) greater (up to 11 mmHg) than those of the girls in subjects age 13 to 17 years. SP levels were most closely correlated with weight (r = 0.595), followed by height (r = 0.560) and age (r = 0.518). When BP levels were adjusted for age and weight, the correlation coefficient of DIN SP with height was negligible (r = 0.026 for boys; r = 0.085 for girls), whereas when adjusted for age and height, the correlation of SP with weight remained high (r = 0.303 for boys; r = 0.216 for girls), indicating that height is not an important independent predictor of BP levels. In conclusion, Dinamap-specific BP standards presented in this report are the only standards that have been generated according to the current BP guidelines recommended by national committees. We found no rational for presenting BP standards according to age and height percentiles.
Collapse
Affiliation(s)
- M K Park
- Department of Cardiology, Department of Pediatrics, Driscoll Children's Hospital, Corpus Christi, TX, USA.
| | | | | |
Collapse
|
47
|
Kang YK, Park MK. Endoplasmic reticulum Ca2+ store: regulation of Ca2+ release and reuptake by intracellular and extracellular Ca2+ in pancreatic acinar cells. Mol Cells 2005; 19:268-78. [PMID: 15879713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
We investigated the effect of cytosolic and extracellular Ca2+ on Ca2+ signals in pancreatic acinar cells by measuring Ca2+ concentration in the cytosol([Ca2+]c) and in the lumen of the ER([Ca2+]Lu). To control buffers and dye in the cytosol, a patch-clamp microelectrode was employed. Acetylcholine released Ca2+ mainly from the basolateral ER-rich part of the cell. The rate of Ca2+ release from the ER was highly sensitive to the buffering of [Ca2+]c whereas ER Ca2+ refilling was enhanced by supplying free Ca2+ to the cytosol with [Ca2+]c clamped at resting levels with a patch pipette containing 10 mM BAPTA and 2 mM Ca2+. Elevation of extracellular Ca2+ to 10 mM from 1 mM raised resting [Ca2+]c slightly and often generated [Ca2+]c oscillations in single or clustered cells. Although pancreatic acinar cells are reported to have extracellular Ca2+-sensing receptors linked to phospholipase C that mobilize Ca2+ from the ER, exposure of cells to 10 mM Ca2+ did not decrease [Ca2+]Lu but rather raised it. From these findings we conclude that 1) ER Ca2+ release is strictly regulated by feedback inhibition of [Ca2+]c, 2) ER Ca2+ refilling is determined by the rate of Ca2+ influx and occurs mainly in the tiny subplasmalemmal spaces, 3) extracellular Ca2+-induced [Ca2+]c oscillations appear to be triggered not by activation of extracellular Ca2+-sensing receptors but by the ER sensitised by elevated [Ca2+]c and [Ca2+]Lu.
Collapse
Affiliation(s)
- Yun Kyung Kang
- Department of Pathology, Inje University Seoul Paik Hospital, Seoul, Korea
| | | |
Collapse
|
48
|
Abstract
BACKGROUND Hiccups are an infrequent result of lateral medullary infarction. Their importance may be underestimated and they can cause distress, exhaustion, and aspiration. Hiccups in lateral medullary infarction remain poorly understood OBJECTIVE To evaluate the relation between the lesional loci of lateral medullary infarction and hiccups. METHODS 51 patients with lateral medullary infarction were investigated by magnetic resonance imaging within three days of the onset of infarction. Seven of the 51 patients developed hiccup. RESULTS All patients with hiccups had middle level lateral medullary lesions, including two with lower level lesions and four with upper level lesions. In the middle level lateral medullary lesions, dorsolateral lesions were most often involved. All patients with lateral medullary infarction presenting with hiccups also had vertigo, dizziness, nausea, vomiting, and dysphagia. CONCLUSIONS The observations suggest that middle level and dorsolateral lesion locations in lateral medullary infarction frequently induce hiccups.
Collapse
Affiliation(s)
- M H Park
- Department of Neurology, Korea University Medical College, 126-1 Anam-dong-5-ga, Sungbuk-gu, Seoul 136-705, Republic of Korea.
| | | | | | | | | | | |
Collapse
|
49
|
Abstract
The excitatory neurotransmitter, glutamate, generates a characteristic burst-pause type of firing in midbrain dopamine neurons in association with the reward behavior, but the cellular mechanism by which glutamate generates these bursts is unknown. Here, we show that the bursts in spontaneously firing dopamine neurons can be generated by the combinative actions of the brief stimulatory and the subsequent Ca(2+)-dependent inhibitory signals in response to glutamate stimulation. The two Ca(2+)-dependent firing-extinction signals are activated by different glutamate receptors. Although the activation of metabotropic glutamate receptors rapidly stopped the enhanced firing through the Ca(2+) release from intracellular stores, the activation of NMDA and AMPA/kainate receptors abolished the firing immediately after termination of the stimulation due to the Ca(2+) accumulation in the cell. These two Ca(2+)-dependent inhibitory mechanisms appear to participate in the generation of characteristic bursts in dopamine neurons by controlling the maximum firing number of single bursts and the duration of post-firing pauses.
Collapse
Affiliation(s)
- Shin Hye Kim
- Department of Physiology and Medical Research Center for Regulation of Neuronal Cell Excitability, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Jangan-ku, Suwon, Korea
| | | | | | | | | |
Collapse
|
50
|
Hee Kim C, Rhee PL, Chul J, Kim YI, So I, Whan Kim K, Park MK, Uhm DY, Mook Kang T. Hypotonic Swelling Increases L-Type Calcium Current in Smooth Muscle Cells of the Human Stomach. Exp Physiol 2004. [DOI: 10.1111/j.1469-445x.2000.02013.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|