1
|
Lu CC, Yen RF, Peng KY, Huang JY, Wu KD, Chueh JS, Lin WY. NP-59 Adrenal Scintigraphy as an Imaging Biomarker to Predict KCNJ5 Mutation in Primary Aldosteronism Patients. Front Endocrinol (Lausanne) 2021; 12:644927. [PMID: 33995277 PMCID: PMC8113947 DOI: 10.3389/fendo.2021.644927] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/06/2021] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Somatic KCNJ5 mutation occurs in half of unilateral primary aldosteronism (PA) and is associated with more severe phenotype. Mutation status can only be identified by tissue sample from adrenalectomy. NP-59 adrenal scintigraphy is a noninvasive functional study for disease activity assessment. This study aimed to evaluate the predictive value of NP-59 adrenal scintigraphy in somatic KCNJ5 mutation among PA patients who received adrenalectomy. METHODS Sixty-two PA patients who had NP-59 adrenal scintigraphy before adrenalectomy with available KCNJ5 mutation status were included. Two semiquantitative parameters, adrenal to liver ratio (ALR) and lesion to contralateral ratio of bilateral adrenal glands (CON) derived from NP-59 adrenal scintigraphy, of mutated and wild-type patients were compared. Cutoff values calculated by receiver-operating characteristic (ROC) analysis were used as a predictor of KCNJ5 mutation. RESULTS Twenty patients had KCNJ5 mutation and 42 patients were wild type. Patients harboring KCNJ5 mutation had both higher ALR and CON (p = 0.0031 and 0.0833, respectively) than wild-type patients. With ALR and CON cutoff of 2.10 and 1.95, the sensitivity and specificity to predict KCNJ5 mutation were 85%, 57% and 45%, 93%, respectively. Among 20 patients with KCNJ5 mutation, 16 showed G151R point mutation (KCNJ5- G151R) and 4 showed L168R point mutation (KCNJ5-L168R), which former one had significantly lower ALR (p=0.0471). CONCLUSION PA patients harboring somatic KCNJ5 mutation had significantly higher NP-59 uptake regarding to ALR and CON than those without mutation. APAs with KCNJ5-L168R point mutation showed significantly higher ALR than those with KCNJ5-G151R point mutation.
Collapse
Affiliation(s)
- Ching-Chu Lu
- Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Ruoh-Fang Yen
- Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Kang-Yung Peng
- Division of Nephrology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Jei-Yie Huang
- Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Kwan-Dun Wu
- Division of Nephrology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Jeff S. Chueh
- Glickman Urological and Kidney Institute, Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
| | - Wan-Yu Lin
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
- Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan
- *Correspondence: Wan-Yu Lin,
| |
Collapse
|
2
|
Lim JS, Plaska SW, Rege J, Rainey WE, Turcu AF. Aldosterone-Regulating Receptors and Aldosterone-Driver Somatic Mutations. Front Endocrinol (Lausanne) 2021; 12:644382. [PMID: 33796077 PMCID: PMC8008747 DOI: 10.3389/fendo.2021.644382] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/08/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Somatic gene mutations that facilitate inappropriate intracellular calcium entrance have been identified in most aldosterone-producing adenomas (APAs). Studies suggest that angiotensin II and adrenocorticotropic hormone (ACTH) augment aldosterone production from APAs. Little is known, however, regarding possible variations in response to hormonal stimuli between APAs with different aldosterone-driver mutations. OBJECTIVE To analyze the transcript expression of type 1 angiotensin II receptors (AGTR1), ACTH receptors (MC2R), and melanocortin 2 receptor accessory protein (MRAP) in APAs with known aldosterone-driver somatic mutations. METHODS RNA was isolated from APAs with mutations in: KCNJ5 (n = 14), ATP1A1 (n = 14), CACNA1D (n = 14), and ATP2B3 (n = 5), and from normal adjacent adrenal tissue (n = 45). Transcript expression of MC2R, MRAP, AGTR1, aldosterone synthase (CYP11B2), 17α-hydroxylase/17,20-lyase (CYP17A1), and 11β-hydroxylase (CYP11B1) were quantified using quantitative RT-PCR and normalized to β-actin. RESULTS Compared to adjacent normal adrenal tissue, APAs had higher transcript levels of CYP11B2 (2,216.4 [1,112.0, 2,813.5]-fold, p < 0.001), MC2R (2.88 [2.00, 4.52]-fold, p < 0.001), and AGTR1 (1.80 [1.02, 2.80]-fold, p < 0.001]), and lower transcript levels of MRAP, CYP17A1, and CYP11B1 (0.28-0.36, p < 0.001 for all). MC2R and CYP11B2 transcripts were lower in APAs with KCNJ5 vs. other mutations (p < 0.01 for both). MC2R expression correlated positively with that of AGTR1 in APAs harboring KCNJ5 and CACNA1D mutations, and with MRAP expression in APAs harboring ATPase mutations. CONCLUSIONS While MC2R and AGTR1 are expressed in all APAs, differences were observed based on the underlying aldosterone-driver somatic mutations. In tandem, our findings suggest that APAs with ATPase-mutations are more responsive to ACTH than KCNJ5-mutated APAs.
Collapse
Affiliation(s)
- Jung Soo Lim
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju Severance Christian Hospital, Wonju, South Korea
| | - Samuel W. Plaska
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Juilee Rege
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - William E. Rainey
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
- Division of Metabolism, Endocrine, and Diabetes, University of Michigan, Ann Arbor, MI, United States
| | - Adina F. Turcu
- Division of Metabolism, Endocrine, and Diabetes, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Adina F. Turcu,
| |
Collapse
|
3
|
Van Aalst E, Yekefallah M, Mehta AK, Eason I, Wylie B. Codon Harmonization of a Kir3.1-KirBac1.3 Chimera for Structural Study Optimization. Biomolecules 2020; 10:biom10030430. [PMID: 32164257 PMCID: PMC7175280 DOI: 10.3390/biom10030430] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/27/2020] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
The expression of functional, folded, and isotopically enriched membrane proteins is an enduring bottleneck for nuclear magnetic resonance (NMR) studies. Indeed, historically, protein yield optimization has been insufficient to allow NMR analysis of many complex Eukaryotic membrane proteins. However, recent work has found that manipulation of plasmid codons improves the odds of successful NMR-friendly protein production. In the last decade, numerous studies showed that matching codon usage patterns in recombinant gene sequences to those in the native sequence is positively correlated with increased protein yield. This phenomenon, dubbed codon harmonization, may be a powerful tool in optimizing recombinant expression of difficult-to-produce membrane proteins for structural studies. Here, we apply this technique to an inward rectifier K+ Channel (Kir) 3.1-KirBac1.3 chimera. Kir3.1 falls within the G protein-coupled inward rectifier K+ (GIRK) channel family, thus NMR studies may inform on the nuances of GIRK gating action in the presence and absence of its G Protein, lipid, and small molecule ligands. In our hands, harmonized plasmids increase protein yield nearly two-fold compared to the traditional ‘fully codon optimized’ construct. We then employ a fluorescence-based functional assay and solid-state NMR correlation spectroscopy to show the final protein product is folded and functional.
Collapse
Affiliation(s)
- Evan Van Aalst
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79423, USA; (E.V.A.); (M.Y.); (I.E.)
| | - Maryam Yekefallah
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79423, USA; (E.V.A.); (M.Y.); (I.E.)
| | - Anil K. Mehta
- National High Magnetic Field Laboratory and McKnight Brain Institute, University of Florida, Box 10015, Gainesville, FL 32610, USA;
| | - Isaac Eason
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79423, USA; (E.V.A.); (M.Y.); (I.E.)
| | - Benjamin Wylie
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79423, USA; (E.V.A.); (M.Y.); (I.E.)
- Correspondence:
| |
Collapse
|
4
|
Yang Q, Lv Q, Feng M, Liu M, Feng Y, Lin S, Yang J, Hu J. Taurine Prevents the Electrical Remodeling in Ach-CaCl 2 Induced Atrial Fibrillation in Rats. Adv Exp Med Biol 2018; 975 Pt 2:821-830. [PMID: 28849502 DOI: 10.1007/978-94-024-1079-2_64] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
OBJECTIVE To study the preventive actions and mechanism of taurine on the electrical remodeling in atrial fibrillation (AF) rats. METHODS Male Wistar rats were injected with the mixture of acetylcholine (Ach) (66 μg/mL)-CaCl2 (10 mg/mL) (i.v.) for 7 days to establish AF model. Taurine was administered in drinking water 1 week before or at the same time of AF model establishment. The duration of AF was monitored by recording ECG of rats during the model establishment. At the end of the experiment, left atrial appendages were cut down to measure the effective refractory period (ERP) by S1-S2 double stimulation method; atrial tissues were collected in order to detect the concentration of K+ and taurine by flame atomic absorption spectrometry and ELISA respectively; total RNA were extracted from the atrium, gene expressions of Kv1.5, Kv4.3, Kir2.1, Kir3.4 were detected by semi-quantitative RT-PCR. RESULTS Taurine administration effectively shortened the AF duration of rats and prolonged atrial ERP than the model and taurine depleted rats. In addition, atrial K+ level in taurine treated groups was significantly reduced nearly to the normal level. Moreover, the mRNA expression levels of Kir3.4 and Kv1.5 were significantly increased in the taurine preventive treated groups. CONCLUSIONS Taurine can prevent the atrial electrical remodeling and decrease the duration of AF in rats by reducing the atrial K+ concentration and up-regulating mRNA expression levels of Kir3.4 and Kv1.5.
Collapse
Affiliation(s)
- Qunhui Yang
- Liaoning Provincial Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning, 110866, People's Republic of China
| | - Qiufeng Lv
- Liaoning Provincial Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning, 110866, People's Republic of China
| | - Man Feng
- Liaoning Provincial Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning, 110866, People's Republic of China
| | - Mei Liu
- Liaoning Provincial Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning, 110866, People's Republic of China
| | - Ying Feng
- Liaoning Provincial Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning, 110866, People's Republic of China
| | - Shumei Lin
- Liaoning Provincial Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning, 110866, People's Republic of China
| | - Jiancheng Yang
- Liaoning Provincial Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning, 110866, People's Republic of China
| | - Jianmin Hu
- Liaoning Provincial Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, Liaoning, 110866, People's Republic of China.
| |
Collapse
|
5
|
Kitamoto T, Suematsu S, Yamazaki Y, Nakamura Y, Sasano H, Matsuzawa Y, Saito J, Omura M, Nishikawa T. Clinical and Steroidogenic Characteristics of Aldosterone-Producing Adenomas With ATPase or CACNA1D Gene Mutations. J Clin Endocrinol Metab 2016; 101:494-503. [PMID: 26606680 DOI: 10.1210/jc.2015-3284] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECT This comparative study clarified the clinical characteristics and in vitro steroidogenic activities of aldosterone-producing adenomas (APAs) harboring ATPase or CACNA1D gene mutations. DESIGN AND PATIENTS Genetic testing was performed on 159 unilateral APAs. Somatic ATPase and CACNA1D gene mutations were analyzed in 42 APA tissues without KCNJ5 gene mutations. RESULTS ATP1A1, ATP2B3, and CACNA1D mutations were detected in one, four, and four patients, respectively. Compared with patients without KCNJ5, ATPase, or CACNA1D mutations (wild type), ATPase mutations tended to have more severe hyperaldosteronism and smaller tumors; those with CACNA1D mutations had clinical characteristics and tumor sizes similar to those with wild-type genes. APAs with ATPase mutations were composed mainly of compact eosinophilic tumor cells, whereas CACNA1D mutations resulted in predominantly clear tumor cells. Aldosterone production in APA cells with ATP2B3 mutations were more responsive to dibutyryl cAMP, whereas those with CACNA1D mutations were more responsive to adrenocorticotropic hormone than the wild-type cells. CONCLUSION APAs with ATPase mutations demonstrated a potentially severe primary aldosteronism phenotype, whereas those with CACNA1D mutations displayed characteristics similar to wild-type APAs. The status of stimulated aldosterone production was also different according to the cell types, suggesting that the regulatory effects of adrenocorticotropic hormone on aldosterone synthesis could possibly vary according to the intracellular signaling involved in hormone production.
Collapse
Affiliation(s)
- Takumi Kitamoto
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Sachiko Suematsu
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Yuto Yamazaki
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Yasuhiro Nakamura
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Hironobu Sasano
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Yoko Matsuzawa
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Jun Saito
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Masao Omura
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| | - Tetsuo Nishikawa
- Endocrinology and Diabetes Center (T.K., S.S., Y.M., J.S., M.O., T.N.), Yokohama Rosai Hospital, Yokohama 222-0036, Japan; and Department of Pathology (Y.Y., Y.N., H.S.), Tohoku University School of Medicine, Sendai 980-8575, Japan
| |
Collapse
|
6
|
Aguirre P, Mena NP, Carrasco CM, Muñoz Y, Pérez-Henríquez P, Morales RA, Cassels BK, Méndez-Gálvez C, García-Beltrán O, González-Billault C, Núñez MT. Iron Chelators and Antioxidants Regenerate Neuritic Tree and Nigrostriatal Fibers of MPP+/MPTP-Lesioned Dopaminergic Neurons. PLoS One 2015; 10:e0144848. [PMID: 26658949 PMCID: PMC4684383 DOI: 10.1371/journal.pone.0144848] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/24/2015] [Indexed: 01/08/2023] Open
Abstract
Neuronal death in Parkinson’s disease (PD) is often preceded by axodendritic tree retraction and loss of neuronal functionality. The presence of non-functional but live neurons opens therapeutic possibilities to recover functionality before clinical symptoms develop. Considering that iron accumulation and oxidative damage are conditions commonly found in PD, we tested the possible neuritogenic effects of iron chelators and antioxidant agents. We used three commercial chelators: DFO, deferiprone and 2.2’-dypyridyl, and three 8-hydroxyquinoline-based iron chelators: M30, 7MH and 7DH, and we evaluated their effects in vitro using a mesencephalic cell culture treated with the Parkinsonian toxin MPP+ and in vivo using the MPTP mouse model. All chelators tested promoted the emergence of new tyrosine hydroxylase (TH)-positive processes, increased axodendritic tree length and protected cells against lipoperoxidation. Chelator treatment resulted in the generation of processes containing the presynaptic marker synaptophysin. The antioxidants N-acetylcysteine and dymetylthiourea also enhanced axodendritic tree recovery in vitro, an indication that reducing oxidative tone fosters neuritogenesis in MPP+-damaged neurons. Oral administration to mice of the M30 chelator for 14 days after MPTP treatment resulted in increased TH- and GIRK2-positive nigra cells and nigrostriatal fibers. Our results support a role for oral iron chelators as good candidates for the early treatment of PD, at stages of the disease where there is axodendritic tree retraction without neuronal death.
Collapse
Affiliation(s)
- Pabla Aguirre
- Iron and Biology of Aging Laboratory, Biology Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
- Research Ring on Oxidative Stress in the Nervous System, Santiago, Chile
| | - Natalia P. Mena
- Iron and Biology of Aging Laboratory, Biology Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Carlos M. Carrasco
- Iron and Biology of Aging Laboratory, Biology Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
- Research Ring on Oxidative Stress in the Nervous System, Santiago, Chile
| | - Yorka Muñoz
- Iron and Biology of Aging Laboratory, Biology Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
- Research Ring on Oxidative Stress in the Nervous System, Santiago, Chile
| | - Patricio Pérez-Henríquez
- Iron and Biology of Aging Laboratory, Biology Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Rodrigo A. Morales
- Iron and Biology of Aging Laboratory, Biology Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Bruce K. Cassels
- Chemobiodynamics Laboratory, Chemistry Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Carolina Méndez-Gálvez
- Chemobiodynamics Laboratory, Chemistry Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Olimpo García-Beltrán
- Chemobiodynamics Laboratory, Chemistry Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
- Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Ibagué, Colombia
| | - Christian González-Billault
- Research Ring on Oxidative Stress in the Nervous System, Santiago, Chile
- Neuronal and Cellular Dynamics Laboratory, Biology Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Marco T. Núñez
- Iron and Biology of Aging Laboratory, Biology Department, Faculty of Sciences, Universidad de Chile, Santiago, Chile
- Research Ring on Oxidative Stress in the Nervous System, Santiago, Chile
- * E-mail:
| |
Collapse
|
7
|
Nishida M, Cadene M, Chait BT, MacKinnon R. Crystal structure of a Kir3.1-prokaryotic Kir channel chimera. EMBO J 2007; 26:4005-15. [PMID: 17703190 PMCID: PMC1994128 DOI: 10.1038/sj.emboj.7601828] [Citation(s) in RCA: 255] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 07/23/2007] [Indexed: 11/08/2022] Open
Abstract
The Kir3.1 K(+) channel participates in heart rate control and neuronal excitability through G-protein and lipid signaling pathways. Expression in Escherichia coli has been achieved by replacing three fourths of the transmembrane pore with the pore of a prokaryotic Kir channel, leaving the cytoplasmic pore and membrane interfacial regions of Kir3.1 origin. Two structures were determined at 2.2 A. The selectivity filter is identical to the Streptomyces lividans K(+) channel within error of measurement (r.m.s.d.<0.2 A), suggesting that K(+) selectivity requires extreme conservation of three-dimensional structure. Multiple K(+) ions reside within the pore and help to explain voltage-dependent Mg(2+) and polyamine blockade and strong rectification. Two constrictions, at the inner helix bundle and at the apex of the cytoplasmic pore, may function as gates: in one structure the apex is open and in the other, it is closed. Gating of the apex is mediated by rigid-body movements of the cytoplasmic pore subunits. Phosphatidylinositol 4,5-biphosphate-interacting residues suggest a possible mechanism by which the signaling lipid regulates the cytoplasmic pore.
Collapse
Affiliation(s)
- Motohiko Nishida
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, Rockefeller University, New York, NY, USA
| | - Martine Cadene
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, NY, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, NY, USA
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, Rockefeller University, New York, NY, USA
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA. Tel.: +1 212 327 7288; Fax: +1 212 327 7289; E-mail:
| |
Collapse
|
8
|
Canciani L, Giaroni C, Zanetti E, Giuliani D, Pisani R, Moro E, Trinchera M, Crema F, Lecchini S, Frigo G. Functional interaction between α2-adrenoceptors, μ- and κ-opioid receptors in the guinea pig myenteric plexus: Effect of chronic desipramine treatment. Eur J Pharmacol 2006; 553:269-79. [PMID: 17055479 DOI: 10.1016/j.ejphar.2006.09.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 09/08/2006] [Accepted: 09/11/2006] [Indexed: 10/24/2022]
Abstract
The existence of a functional interplay between alpha(2)-adrenoceptor and opioid receptor inhibitory pathways modulating neurotransmitter release has been demonstrated in the enteric nervous system by development of sensitivity changes to alpha(2)-adrenoceptor, mu- and kappa-opioid receptor agents on enteric cholinergic neurons after chronic sympathetic denervation. In the present study, to further examine this hypothesis we evaluated whether manipulation of alpha(2)-adrenoceptor pathways by chronic treatment with the antidepressant drug, desipramine (10 mg/kg i.p. daily, for 21 days), could entail changes in enteric mu- and kappa-opioid receptor pathways in the myenteric plexus of the guinea pig distal colon. In this region, subsensitivity to the inhibitory effect of both UK14,304 and U69,593, respectively alpha(2A)-adrenoceptor and kappa-opioid receptor agonist, on the peristaltic reflex developed after chronic desipramine treatment. On opposite, in these experimental conditions, supersensitivity developed to the inhibitory effect of [D-Ala, N-Me-Phe4-Gly-ol5]-enkephalin (DAMGO), mu-opioid receptor agonist, on propulsion velocity. Immunoreactive expression levels of alpha(2A)-adrenoceptors, mu- and kappa-opioid receptors significantly decreased in the myenteric plexus of the guinea pig colon after chronic desipramine treatment. In these experimental conditions, mRNA levels of alpha(2A)-adrenoceptors, mu- and kappa-opioid receptors significantly increased, excluding a direct involvement of transcription mechanisms in the regulation of receptor expression. Levels of G protein-coupled receptor kinase 2/3 and of inhibitory G(i/o) proteins were significantly reduced in the myenteric plexus after chronic treatment with desipramine. Such changes might represent possible molecular mechanisms involved in the development of subsensitivity to UK14,304 and U69,593 on the efficiency of peristalsis. Alternative molecular mechanisms, including a higher efficiency in the coupling between receptor activation and downstream intracellular effector systems, possibly independent from inhibitory G(i/o) proteins, may be accounted for the development of supersensitivity to DAMGO. Increased sensitivity to the mu-opioid agonist might compensate for the development of alpha(2A)-adrenoceptor and kappa-opioid receptor subsensitivity. On the whole, the present data further strengthen the concept that, manipulation of alpha(2)-adrenergic inhibitory receptor pathways in the enteric nervous system entails changes in opioid inhibitory receptor pathways, which might be involved in maintaining homeostasis as suggested for mu-opioid, but not for kappa-opioid receptors.
Collapse
MESH Headings
- Adrenergic alpha-2 Receptor Agonists
- Adrenergic alpha-Agonists/pharmacology
- Analgesics/pharmacology
- Analgesics, Opioid/pharmacology
- Animals
- Antidepressive Agents, Tricyclic/pharmacology
- Benzeneacetamides/pharmacology
- Blotting, Western
- Brimonidine Tartrate
- Desipramine/pharmacology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- G Protein-Coupled Inwardly-Rectifying Potassium Channels/biosynthesis
- GTP-Binding Proteins/biosynthesis
- Guinea Pigs
- In Vitro Techniques
- Male
- Myenteric Plexus/drug effects
- Peristalsis/drug effects
- Pyrrolidines/pharmacology
- Quinoxalines/pharmacology
- RNA, Messenger/biosynthesis
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/drug effects
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/drug effects
- Reverse Transcriptase Polymerase Chain Reaction
- Synaptosomes/drug effects
- Synaptosomes/metabolism
Collapse
Affiliation(s)
- Luca Canciani
- Clinical and Applied Pharmacology Centre, University of Insubria and University of Pavia, via O Rossi 9, I-21100 Varese, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Smith AJ, Partridge CJ, Asipu A, Mair LA, Hunter M, Sivaprasadarao A. Increased ATP-sensitive K+ channel expression during acute glucose deprivation. Biochem Biophys Res Commun 2006; 348:1123-31. [PMID: 16904639 DOI: 10.1016/j.bbrc.2006.07.170] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 07/27/2006] [Indexed: 11/16/2022]
Abstract
ATP-sensitive potassium (KATP) channels play a central role in glucose-stimulated insulin secretion (GSIS) by pancreatic beta-cells. Activity of these channels is determined by their open probability (Po) and the number of channels present in a cell. Glucose is known to reduce Po, but whether it also affects the channel density is unknown. Using INS-1 model beta-cell line, we show that the expression of K(ATP) channel subunits, Kir6.2 and SUR1, is high at low glucose, but declines sharply when the ambient glucose concentration exceeds 5mM. In response to glucose deprivation, channel synthesis increases rapidly by up-regulating translation of existing mRNAs. The effects of glucose deprivation could be mimicked by pharmacological activation of 5'-AMP-activated protein kinase with 5-aminoimidazole-4-carboxamide ribonucleotide and metformin. Pancreatic beta-cells which have lost their ability for GSIS do not show such changes implicating a possible (patho-)physiological link between glucose-regulated KATP channel expression and the capacity for normal GSIS.
Collapse
Affiliation(s)
- Andrew J Smith
- Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, UK
| | | | | | | | | | | |
Collapse
|
10
|
Koyrakh L, Luján R, Colón J, Karschin C, Kurachi Y, Karschin A, Wickman K. Molecular and cellular diversity of neuronal G-protein-gated potassium channels. J Neurosci 2006; 25:11468-78. [PMID: 16339040 PMCID: PMC6725904 DOI: 10.1523/jneurosci.3484-05.2005] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Neuronal G-protein-gated potassium (GIRK) channels mediate the inhibitory effects of many neurotransmitters. Although the overlapping distribution of GIRK subunits suggests that channel composition varies in the CNS, little direct evidence supports the existence of structural or functional diversity in the neuronal GIRK channel repertoire. Here we show that the GIRK channels linked to GABAB receptors differed in two neuron populations. In the substantia nigra, GIRK2 was the principal subunit, and it was found primarily in dendrites of neurons in the substantia nigra pars compacta (SNc). Baclofen evoked prominent barium-sensitive outward current in dopamine neurons of the SNc from wild-type mice, but this current was completely absent in neurons from GIRK2 knock-out mice. In the hippocampus, all three neuronal GIRK subunits were detected. The loss of GIRK1 or GIRK2 was correlated with equivalent, dramatic reductions in baclofen-evoked current in CA1 neurons. Virtually all of the barium-sensitive component of the baclofen-evoked current was eliminated with the ablation of both GIRK2 and GIRK3, indicating that channels containing GIRK3 contribute to the postsynaptic inhibitory effect of GABAB receptor activation. The impact of GIRK subunit ablation on baclofen-evoked current was consistent with observations that GIRK1, GIRK2, and GABAB receptors were enriched in lipid rafts isolated from mouse brain, whereas GIRK3 was found primarily in higher-density membrane fractions. Altogether, our data show that different GIRK channel subtypes can couple to GABAB receptors in vivo. Furthermore, subunit composition appears to specify interactions between GIRK channels and organizational elements involved in channel distribution and efficient receptor coupling.
Collapse
Affiliation(s)
- Lev Koyrakh
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Thompson L, Barraud P, Andersson E, Kirik D, Björklund A. Identification of dopaminergic neurons of nigral and ventral tegmental area subtypes in grafts of fetal ventral mesencephalon based on cell morphology, protein expression, and efferent projections. J Neurosci 2006; 25:6467-77. [PMID: 16000637 PMCID: PMC6725273 DOI: 10.1523/jneurosci.1676-05.2005] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [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: 11/21/2022] Open
Abstract
Transplants of fetal ventral mesencephalic tissue are known to contain a mixture of two major dopamine (DA) neuron types: the A9 neurons of the substantia nigra pars compacta (SNpc) and the A10 neurons of the ventral tegmental area (VTA). Previous studies have suggested that these two DA neuron types may differ in their growth characteristics, but, because of technical limitations, it has so far been difficult to identify the two subtypes in fetal ventral mesencephalon (VM) grafts and trace their axonal projections. Here, we have made use of a transgenic mouse expressing green fluorescent protein (GFP) under the tyrosine hydroxylase promoter. The expression of the GFP reporter allowed for visualization of the grafted DA neurons and their axonal projections within the host brain. We show that the SNpc and VTA neuron subtypes in VM grafts can be identified on the basis of their morphology and location within the graft, and their expression of a G-protein-gated inwardly rectifying K+ channel subunit (Girk2) and calbindin, respectively, and also that the axonal projections of the two DA neuron types are markedly different. By retrograde axonal tracing, we show that dopaminergic innervation of the striatum is derived almost exclusively from the Girk2-positive SNpc cells, whereas the calbindin-positive VTA neurons project to the frontal cortex and probably also other forebrain areas. The results suggest the presence of axon guidance and target recognition mechanisms in the DA-denervated forebrain that can guide the growing axons to their appropriate targets and indicate that cell preparations used for cell replacement in Parkinson's disease will be therapeutically useful only if they contain cells capable of generating the correct nigral DA neuron phenotype.
Collapse
Affiliation(s)
- Lachlan Thompson
- Wallenberg Neuroscience Center, Department of Experimental Medical Research, Lund Strategic Center for Stem Cell Biology and Cell Therapy, Lund University, SE-221 84 Lund, Sweden.
| | | | | | | | | |
Collapse
|
12
|
Plummer HK, Dhar MS, Cekanova M, Schuller HM. Expression of G-protein inwardly rectifying potassium channels (GIRKs) in lung cancer cell lines. BMC Cancer 2005; 5:104. [PMID: 16109170 PMCID: PMC1208863 DOI: 10.1186/1471-2407-5-104] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Accepted: 08/18/2005] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Previous data from our laboratory has indicated that there is a functional link between the beta-adrenergic receptor signaling pathway and the G-protein inwardly rectifying potassium channel (GIRK1) in human breast cancer cell lines. We wanted to determine if GIRK channels were expressed in lung cancers and if a similar link exists in lung cancer. METHODS GIRK1-4 expression and levels were determined by reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR. GIRK protein levels were determined by western blots and cell proliferation was determined by a 5-bromo-2'-deoxyuridine (BrdU) assay. RESULTS GIRK1 mRNA was expressed in three of six small cell lung cancer (SCLC) cell lines, and either GIRK2, 3 or 4 mRNA expression was detected in all six SCLC cell lines. Treatment of NCI-H69 with beta2-adrenergic antagonist ICI 118,551 (100 microM) daily for seven days led to slight decreases of GIRK1 mRNA expression levels. Treatment of NCI-H69 with the beta-adrenergic agonist isoproterenol (10 microM) decreased growth rates in these cells. The GIRK inhibitor U50488H (2 microM) also inhibited proliferation, and this decrease was potentiated by isoproterenol. In the SCLC cell lines that demonstrated GIRK1 mRNA expression, we also saw GIRK1 protein expression. We feel these may be important regulatory pathways since no expression of mRNA of the GIRK channels (1 & 2) was found in hamster pulmonary neuroendocrine cells, a suggested cell of origin for SCLC, nor was GIRK1 or 2 expression found in human small airway epithelial cells. GIRK (1,2,3,4) mRNA expression was also seen in A549 adenocarcinoma and NCI-H727 carcinoid cell lines. GIRK1 mRNA expression was not found in tissue samples from adenocarcinoma or squamous cancer patients, nor was it found in NCI-H322 or NCI-H441 adenocarcinoma cell lines. GIRK (1,3,4) mRNA expression was seen in three squamous cell lines, GIRK2 was only expressed in one squamous cell line. However, GIRK1 protein expression was not seen in any non-SCLC cells. CONCLUSION We feel that this data may indicate that stimulation of GIRK1 or GIRK2 channels may be important in lung cancer. Stimulation of GIRK channels and beta-adrenergic signaling may activate similar signaling pathways in both SCLC and breast cancer, but lead to different results.
Collapse
Affiliation(s)
- Howard K Plummer
- Molecular Cancer Analysis Laboratory, Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4542, USA
| | - Madhu S Dhar
- Molecular Cancer Analysis Laboratory, Department of Pathobiology, and Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4542, USA
| | - Maria Cekanova
- Experimental Oncology Laboratory, Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4542, USA
| | - Hildegard M Schuller
- Experimental Oncology Laboratory, Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996-4542, USA
| |
Collapse
|