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Li M, Lei P, Shuang S, Dong C, Zhang L. Visualization of polarity changes in endoplasmic reticulum (ER) autophagy and rheumatoid arthritis mice with near-infrared ER-targeted fluorescent probe. Talanta 2024; 275:126141. [PMID: 38677168 DOI: 10.1016/j.talanta.2024.126141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 04/18/2024] [Accepted: 04/20/2024] [Indexed: 04/29/2024]
Abstract
The crucial cellular activities for maintaining normal cell functions heavily rely on the polarity of the endoplasmic reticulum (ER). Understanding how the polarity shifts, particularly in the context of ER autophagy (ER-phagy), holds significant promise for advancing knowledge of disorders associated with ER stress. Herein, a polarity-sensitive fluorescent probe CDI was easily synthesized from the condensation reaction of coumarin and dicyanoisophorone. CDI was composed of coumarin as the electron-donating moiety (D), ethylene and phenyl ring as the π-conjugation bridge, and malononitrile as the electron-accepting moiety (A), forming a typical D-π-A molecular configuration that recognition in the near-infrared (NIR) region. The findings suggested that as the polarity increased, the fluorescence intensity of CDI decreased, and it was accompanied by a redshift of emission wavelength at the excitation wavelength of 524 nm, shifting from 641 nm to 721 nm. Significantly, CDI exhibited a notable ability to effectively target ER and enabled real-time monitoring of ER-phagy induced by starvation or drugs. Most importantly, alterations in polarity can be discerned through in vivo imaging in mice model of rheumatoid arthritis (RA). CDI has been proven effective in evaluating the therapeutic efficacy of drugs for RA. ER fluorescent probe CDI can be optically activated in lysosomes, providing a sensitive tool for studying ER-phagy in biology and diseases.
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Affiliation(s)
- Minglu Li
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Third Hospital of Shanxi Medical University, Tongji Shanxi Hospital, Shanxi Province Clinical Theranostics Technology Innovation Center for Immunologic and Rheumatic Diseases, Shanxi Province Clinical Research Center for Dermatologic and Immunologic Disease(Rheumatic diseases), Taiyuan, 030032, China
| | - Peng Lei
- College of Chemistry and Chemical Engineering & Institute of Environmental Science, Shanxi University, Taiyuan, 030006, China
| | - Shaomin Shuang
- College of Chemistry and Chemical Engineering & Institute of Environmental Science, Shanxi University, Taiyuan, 030006, China
| | - Chuan Dong
- College of Chemistry and Chemical Engineering & Institute of Environmental Science, Shanxi University, Taiyuan, 030006, China
| | - Liyun Zhang
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Third Hospital of Shanxi Medical University, Tongji Shanxi Hospital, Shanxi Province Clinical Theranostics Technology Innovation Center for Immunologic and Rheumatic Diseases, Shanxi Province Clinical Research Center for Dermatologic and Immunologic Disease(Rheumatic diseases), Taiyuan, 030032, China.
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Zhou M, Li TS, Abe H, Akashi H, Suzuki R, Bando Y. Expression levels of K ATP channel subunits and morphological changes in the mouse liver after exposure to radiation. World J Exp Med 2024; 14:90374. [PMID: 38948415 PMCID: PMC11212743 DOI: 10.5493/wjem.v14.i2.90374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/28/2024] [Accepted: 03/27/2024] [Indexed: 06/19/2024] Open
Abstract
BACKGROUND ATP sensitive K+ (KATP) channels are ubiquitously distributed in various of cells and tissues, including the liver. They play a role in the pathogenesis of myocardial and liver ischemia. AIM To evaluate the radiation-induced changes in the expression of KATP channel subunits in the mouse liver to understand the potential role of KATP channels in radiation injury. METHODS Adult C57BL/6 mice were randomly exposed to γ-rays at 0 Gy (control, n = 2), 0.2 Gy (n = 6), 1 Gy (n = 6), or 5 Gy (n = 6). The livers were removed 3 and 24 h after radiation exposure. Hematoxylin and eosin staining was used for morphological observation; immunohistochemical staining was applied to determine the expression of KATP channel subunits in the liver tissue. RESULTS Compared with the control group, the livers exposed to 0.2 Gy γ-ray showed an initial increase in the expression of Kir6.1 at 3 h, followed by recovery at 24 h after exposure. Exposure to a high dose of 5.0 Gy resulted in decreased expression of Kir6.1 and increased expression of SUR2B at 24 h. However, the expression of Kir6.2, SUR1, or SUR2A had no remarkable changes at 3 and 24 h after exposure to any of these doses. CONCLUSION The expression levels of Kir6.1 and SUR2B in mouse liver changed differently in response to different radiation doses, suggesting a potential role for them in radiation-induced liver injury.
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Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Tao-Sheng Li
- Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki 852-8523, Japan
| | - Hiroshi Abe
- Sendai Old Age Refresh Station, A Long-term Care Health Facility, Sendai 981-1105, Japan
| | - Hideo Akashi
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Ryoji Suzuki
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Yoshio Bando
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
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Lu S, Dai Z, Cui Y, Kong DM. Recent Development of Advanced Fluorescent Molecular Probes for Organelle-Targeted Cell Imaging. BIOSENSORS 2023; 13:360. [PMID: 36979572 PMCID: PMC10046058 DOI: 10.3390/bios13030360] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 02/10/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Fluorescent molecular probes are very powerful tools that have been generally applied in cell imaging in the research fields of biology, pathology, pharmacology, biochemistry, and medical science. In the last couple of decades, numerous molecular probes endowed with high specificity to particular organelles have been designed to illustrate intracellular images in more detail at the subcellular level. Nowadays, the development of cell biology has enabled the investigation process to go deeply into cells, even at the molecular level. Therefore, probes that can sketch a particular organelle's location while responding to certain parameters to evaluate intracellular bioprocesses are under urgent demand. It is significant to understand the basic ideas of organelle properties, as well as the vital substances related to each unique organelle, for the design of probes with high specificity and efficiency. In this review, we summarize representative multifunctional fluorescent molecular probes developed in the last decade. We focus on probes that can specially target nuclei, mitochondria, endoplasmic reticulums, and lysosomes. In each section, we first briefly introduce the significance and properties of different organelles. We then discuss how probes are designed to make them highly organelle-specific. Finally, we also consider how probes are constructed to endow them with additional functions to recognize particular physical/chemical signals of targeted organelles. Moreover, a perspective on the challenges in future applications of highly specific molecular probes in cell imaging is also proposed. We hope that this review can provide researchers with additional conceptual information about developing probes for cell imaging, assisting scientists interested in molecular biology, cell biology, and biochemistry to accelerate their scientific studies.
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Affiliation(s)
- Sha Lu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Zhiqi Dai
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Yunxi Cui
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - De-Ming Kong
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Centre for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China
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Yamanaka M, Tamura Y, Kuribayashi-Okuma E, Uchida S, Shibata S. Nicorandil protects podocytes via modulation of antioxidative capacity in acute puromycin aminonucleoside-induced nephrosis in rats. Am J Physiol Renal Physiol 2023; 324:F168-F178. [PMID: 36454699 PMCID: PMC9844977 DOI: 10.1152/ajprenal.00144.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Nephrotic syndrome, characterized by proteinuria and hypoalbuminemia, results from the dysregulation of glomerular podocytes and is a significant cause of end-stage kidney disease. Patients with idiopathic nephrotic syndrome are generally treated with immunosuppressive agents; however, these agents produce various adverse effects. Previously, we reported the renoprotective effects of a stimulator of the mitochondrial ATP-dependent K+ channel (MitKATP), nicorandil, in a remnant kidney model. Nonetheless, the cellular targets of these effects remain unknown. Here, we examined the effect of nicorandil on puromycin aminonucleoside-induced nephrosis (PAN) rats, a well-established model of podocyte injury and human nephrotic syndrome. PAN was induced using a single intraperitoneal injection. Nicorandil was administered orally at 30 mg/kg/day. We found that proteinuria and hypoalbuminemia in PAN rats were significantly ameliorated following nicorandil treatment. Immunostaining and ultrastructural analysis under electron microscopy demonstrated that podocyte injury in PAN rats showed a significant partial attenuation following nicorandil treatment. Nicorandil ameliorated the increase in the oxidative stress markers nitrotyrosine and 8-hydroxy-2-deoxyguanosine in glomeruli. Conversely, nicorandil prevented the decrease in levels of the antioxidant enzyme manganese superoxide dismutase in PAN rats. We found that mitochondrial Ca2+ uniporter levels in glomeruli were higher in PAN rats than in control rats, and this increase was significantly attenuated by nicorandil. We conclude that stimulation of MitKATP by nicorandil reduces proteinuria by attenuating podocyte injury in PAN nephrosis, which restores mitochondrial antioxidative capacity, possibly through mitochondrial Ca2+ uniporter modulation. These data indicate that MitKATP may represent a novel target for podocyte injury and nephrotic syndrome.NEW & NOTEWORTHY Our findings suggest that the mitochondrial Ca2+ uniporter may be an upstream regulator of manganese superoxide dismutase and indicate a biochemical basis for the interaction between the ATP-sensitive K+ channel and Ca2+ signaling. We believe that our study makes a significant contribution to the literature because our results indicate that the ATP-sensitive K+ channel may be a potential therapeutic target for podocyte injury and nephrotic syndrome.
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Affiliation(s)
- Masaki Yamanaka
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshifuru Tamura
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Emiko Kuribayashi-Okuma
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shunya Uchida
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
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Le Ribeuz H, Masson B, Dutheil M, Boët A, Beauvais A, Sabourin J, De Montpreville VT, Capuano V, Mercier O, Humbert M, Montani D, Antigny F. Involvement of SUR2/Kir6.1 channel in the physiopathology of pulmonary arterial hypertension. Front Cardiovasc Med 2023; 9:1066047. [PMID: 36704469 PMCID: PMC9871631 DOI: 10.3389/fcvm.2022.1066047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/20/2022] [Indexed: 01/12/2023] Open
Abstract
Aims We hypothesized that the ATP-sensitive K+ channels (KATP) regulatory subunit (ABCC9) contributes to PAH pathogenesis. ABCC9 gene encodes for two regulatory subunits of KATP channels: the SUR2A and SUR2B proteins. In the KATP channel, the SUR2 subunits are associated with the K+ channel Kir6.1. We investigated how the SUR2/Kir6.1 channel contributes to PAH pathogenesis and its potential as a therapeutic target in PAH. Methods and results Using in vitro, ex vivo, and in vivo approaches, we analyzed the localization and expression of SUR2A, SUR2B, and Kir6.1 in the pulmonary vasculature of controls and patients with PAH as in experimental pulmonary hypertension (PH) rat models and its contribution to PAH physiopathology. Finally, we deciphered the consequences of in vivo activation of SUR2/Kir6.1 in the monocrotaline (MCT)-induced PH model. We found that SUR2A, SUR2B, and Kir6.1 were expressed in the lungs of controls and patients with PAH and MCT-induced PH rat models. Organ bath studies showed that SUR2 activation by pinacidil induced relaxation of pulmonary arterial in rats and humans. In vitro experiments on human pulmonary arterial smooth muscle cells and endothelial cells (hPASMCs and hPAECs) in controls and PAH patients showed decreased cell proliferation and migration after SUR2 activation. We demonstrated that SUR2 activation in rat right ventricular (RV) cardiomyocytes reduced RV action potential duration by patch-clamp. Chronic pinacidil administration in control rats increased heart rate without changes in hemodynamic parameters. Finally, in vivo pharmacological activation of SUR2 on MCT and Chronic-hypoxia (CH)-induced-PH rats showed improved PH. Conclusion We showed that SUR2A, SUR2B, and Kir6.1 are presented in hPASMCs and hPAECs of controls and PAH patients. In vivo SUR2 activation reduced the MCT-induced and CH-induced PH phenotype, suggesting that SUR2 activation should be considered for treating PAH.
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Affiliation(s)
- Hélène Le Ribeuz
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Bastien Masson
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Mary Dutheil
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
- Hôptal Marie Lannelongue, Groupe Hospitalier Paris Saint-Joseph, Le Plessis Robinson, France
| | - Angèle Boët
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Antoine Beauvais
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Jessica Sabourin
- Inserm, UMR-S 1180, Signalisation et Physiopathologie Cardiovasculaire, Université Paris-Saclay, Orsay, France
| | | | - Véronique Capuano
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
- Hôptal Marie Lannelongue, Groupe Hospitalier Paris Saint-Joseph, Le Plessis Robinson, France
| | - Olaf Mercier
- Service de Chirurgie Thoracique, Vasculaire et Transplantation Cardio-Pulmonaire, Hôpital Marie Lannelongue, Groupe Hospitalier Paris Saint Joseph, Le Plessis Robinson, France
| | - Marc Humbert
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
- Assistance Publique–Hôpitaux de Paris (AP-HP), Service de Pneumologie et Soins Intensifs Respiratoires, Centre de Référence de l’Hypertension Pulmonaire, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - David Montani
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
- Assistance Publique–Hôpitaux de Paris (AP-HP), Service de Pneumologie et Soins Intensifs Respiratoires, Centre de Référence de l’Hypertension Pulmonaire, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Fabrice Antigny
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
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Sánchez-Vázquez VH, Martínez-Martínez E, Gallegos-Gómez ML, Arias JM, Pallafacchina G, Rizzuto R, Guerrero-Hernández A. Heterogeneity of the endoplasmic reticulum Ca 2+ store determines colocalization with mitochondria. Cell Calcium 2023; 109:102688. [PMID: 36538845 DOI: 10.1016/j.ceca.2022.102688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 11/14/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022]
Abstract
Contact sites between the endoplasmic reticulum (ER) and mitochondria play a pivotal role in cell signaling, and the interaction between these organelles is dynamic and finely regulated. We have studied the role of ER Ca2+ concentration ([Ca2+]ER) in modulating this association in HeLa and HEK293 cells and human fibroblasts. According to Manders' coefficient, ER-mitochondria colocalization varied depending on the ER marker; it was the highest with ER-Tracker and the lowest with ER Ca2+ indicators (Mag-Fluo-4, erGAP3, and G-CEPIA1er) in both HeLa cells and human fibroblasts. Only GEM-CEPIA1er displayed a high colocalization with elongated mitochondria in HeLa cells, this ER Ca2+ indicator reveals low Ca2+ regions because this ion quenches its fluorescence. On the contrary, the typical rounded and fragmented mitochondria of HEK293 cells colocalized with Mag-Fluo-4 and, to a lesser extent, with GEM-CEPIA1er. The ablation of the three IP3R isoforms in HEK293 cells increased mitochondria-GEM-CEPIA1er colocalization. This pattern of colocalization was inversely correlated with the rate of ER Ca2+ leak evoked by thapsigargin (Tg). Moreover, Tg and Histamine in the absence of external Ca2+ increased mitochondria-ER colocalization. On the contrary, in the presence of external Ca2+, both Bafilomycin A1 and Tg reduced the mitochondria-ER interaction. Notably, knocking down MCU decreased mitochondria-ER colocalization. Overall, our data suggest that the [Ca2+] is not homogenous within the ER lumen and that mitochondria-ER interaction is modulated by the ER Ca2+ leak and the [Ca2+]i.
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Affiliation(s)
| | | | | | - Juan M Arias
- Programa de Neurociencias-UIICSE, Facultad de Estudios Superiores Iztacala, UNAM; Tlalnepantla de Baz, Estado de México, 54090, Mexico
| | - Giorgia Pallafacchina
- CNR, Neuroscience Institute, Padua, 35131. Italy; Department of Biomedical Sciences, University of Padua, Padua, 35131. Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, Padua, 35131. Italy
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Weiss M, Nikisher B, Haran H, Tefft K, Adams J, Edwards JG. High throughput screen of small molecules as potential countermeasures to galactic cosmic radiation induced cellular dysfunction. LIFE SCIENCES IN SPACE RESEARCH 2022; 35:76-87. [PMID: 36336373 DOI: 10.1016/j.lssr.2022.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/23/2022] [Accepted: 06/16/2022] [Indexed: 06/16/2023]
Abstract
Space travel increases galactic cosmic ray exposure to flight crews and this is significantly elevated once travel moves beyond low Earth orbit. This includes combinations of high energy protons and heavy ions such as 56Fe or 16O. There are distinct differences in the biological response to low-energy transfer (x-rays) or high-energy transfer (High-LET). However, given the relatively low fluence rate of exposure during flight operations, it might be possible to manage these deleterious effects using small molecules currently available. Virtually all reports to date examining small molecule management of radiation exposure are based on low-LET challenges. To that end an FDA approved drug library (725 drugs) was used to perform a high throughput screen of cultured cells following exposure to galactic cosmic radiation. The H9c2 myoblasts, ES-D3 pluripotent cells, and Hy926 endothelial cell lines were exposed to a single exposure (75 cGy) using the 5-ion GCRsim protocol developed at the NASA Space Radiation Laboratory (NSRL). Following GCR exposure cells were maintained for up to two weeks. For each drug (@10µM), a hierarchical cumulative score was developed incorporating measures of mitochondrial and cellular function, oxidant stress and cell senescence. The top 160 scores were retested following a similar protocol using 1µM of each drug. Within the 160 drugs, 33 are considered to have an anti-inflammatory capacity, while others also indirectly suppressed pro-inflammatory pathways or had noted antioxidant capacity. Lead candidates came from different drug classes that included angiotensin converting enzyme inhibitors or AT1 antagonists, COX2 inhibitors, as well as drugs mediated by histamine receptors. Surprisingly, different classes of anti-diabetic medications were observed to be useful including sulfonylureas and metformin. Using a hierarchical decision structure, we have identified several lead candidates. That no one drug or even drug class was completely successful across all parameters tested suggests the complexity of managing the consequences of galactic cosmic radiation exposure.
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Affiliation(s)
- M Weiss
- Department of Physiology, New York Medical College, Valhalla, New York
| | - B Nikisher
- Department of Physiology, New York Medical College, Valhalla, New York
| | - H Haran
- Department of Physiology, New York Medical College, Valhalla, New York
| | - K Tefft
- Department of Physiology, New York Medical College, Valhalla, New York
| | - J Adams
- Department of Physiology, New York Medical College, Valhalla, New York
| | - J G Edwards
- Department of Physiology, New York Medical College, Valhalla, New York.
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Singh D, Rajput D, Kanvah S. Fluorescent probes for targeting endoplasmic reticulum: design strategies and their applications. Chem Commun (Camb) 2022; 58:2413-2429. [PMID: 35089303 DOI: 10.1039/d1cc06944f] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Advances in developing organic fluorescent probes and fluorescence imaging techniques have enhanced our understanding of cell biology. The endoplasmic reticulum (ER) is a dynamic structure that plays a crucial role in protein synthesis, post-translational modifications, and lipid metabolism. The malfunction of ER contributes to several physiological and pathological conditions. Therefore, the investigations on the imaging and role of ER have attracted a lot of attention. Due to their simplicity, synthetic tunability, photostability, high quantum yields, easier cellular uptake, and lower cytotoxicity, organic fluorophores offer invaluable tools for the precision targeting of various cellular organelles and probe ER dynamics. The precision staining is made possible by incorporating specific functional groups having preferential and local organelle biomolecular interactions. For instance, functional moieties such as methyl sulfonamide, sulfonylurea, and pentafluorophenyl assist in ER targeting and thus have become essential tools to probe a deeper understanding of their dynamics. Furthermore, dual-function fluorescent probes that simultaneously image ER and detect specific physiological parameters or biological analytes were achieved by introducing special recognition or chemically reactive sites. This article attempts to comprehensively capture various design strategies currently employed by researchers utilizing small organic molecules to target the ER and detect specific analytes.
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Affiliation(s)
- Deepmala Singh
- Department of Chemistry, Indian Institute of Technology, Gandhinagar Palaj, Gandhinagar, Gujarat-382055, India.
| | - Deeksha Rajput
- Department of Chemistry, Indian Institute of Technology, Gandhinagar Palaj, Gandhinagar, Gujarat-382055, India.
| | - Sriram Kanvah
- Department of Chemistry, Indian Institute of Technology, Gandhinagar Palaj, Gandhinagar, Gujarat-382055, India.
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Abstract
Fluorescent tools have emerged as an important tool for studying the distinct chemical microenvironments of organelles, due to their high specificity and ability to be used in non-destructive, live cellular studies. These tools fall largely in two categories: exogenous fluorescent dyes, or endogenous labels such as genetically encoded fluorescent proteins. In both cases, the probe must be targeted to the organelle of interest. To date, many organelle-targeted fluorescent tools have been reported and used to uncover new information about processes that underpin health and disease. However, the majority of these tools only apply a handful of targeting groups, and less-studied organelles have few robust targeting strategies. While the development of new, robust strategies is difficult, it is essential to develop such strategies to allow for the development of new tools and broadening the effective study of organelles. This review aims to provide a comprehensive overview of the major targeting strategies for both endogenous and exogenous fluorescent cargo, outlining the specific challenges for targeting each organelle type and as well as new developments in the field.
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Affiliation(s)
- Jiarun Lin
- School of Chemistry, The University of Sydney, NSW, 2006, Australia.
- The University of Sydney Nano Institute (Sydney Nano), The University of Sydney, NSW 2006, Australia
| | - Kylie Yang
- School of Chemistry, The University of Sydney, NSW, 2006, Australia.
| | - Elizabeth J New
- School of Chemistry, The University of Sydney, NSW, 2006, Australia.
- The University of Sydney Nano Institute (Sydney Nano), The University of Sydney, NSW 2006, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, NSW 2006, Australia
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10
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Lu J, Pan SS, Wang QT, Yuan Y. Alterations of Cardiac K ATP Channels and Autophagy Contribute in the Late Cardioprotective Phase of Exercise Preconditioning. Int Heart J 2018; 59:1106-1115. [PMID: 30101842 DOI: 10.1536/ihj.17-003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The cardiac effects of exercise preconditioning (EP) are well established; however, the mechanisms involving cardiac ATP-sensitive potassium channel (KATP channel) subunits and autophagy are yet to be fully established. The present work aims to investigate the alterations of cardiac KATP channel subunits Kir6.2, SUR2A, and autophagy-related LC3 during the late cardioprotective phase of EP against exhaustive exercise-induced myocardial injury. Rats run on treadmill for four running time intervals, each with 10 minutes running and rest. Exhaustive exercise was performed 24 h after EP. Cardiac biomarkers, cTnI and NT-proBNP, along with the histological stain, were served as indicators of myocardial injury. Cardiac KATP channel subunits Kir6.2 and SUR2A were analyzed in this study, and autophagy was evaluated by LC3. The results revealed that EP reduced the exhaustive exercise-induced high level of serum cTnI and myocardial ischemia/hypoxia; however, it did not reveal any changes in the serum NT-proBNP level or cardiac BNP. Cardiac SUR2A mRNA significantly upregulated during the exhaustive exercise. The high levels of Kir6.2, SUR2A, LC3IIpuncta and LC3II turnover observed after exhaustive exercise were significantly mitigated by EP in the late phase. These results suggest that EP alleviates myocardial injury induced by exhaustive exercise through the downregulation of cardiac KATP channels and autophagy.
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Affiliation(s)
- Jiao Lu
- School of Kinesiology, Shanghai University of Sport
| | | | | | - Yang Yuan
- School of Kinesiology, Shanghai University of Sport
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11
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Deryagin OG, Gavrilova SA, Gainutdinov KL, Golubeva AV, Andrianov VV, Yafarova GG, Buravkov SV, Koshelev VB. Molecular Bases of Brain Preconditioning. Front Neurosci 2017; 11:427. [PMID: 28790886 PMCID: PMC5524930 DOI: 10.3389/fnins.2017.00427] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 07/11/2017] [Indexed: 12/20/2022] Open
Abstract
Preconditioning of the brain induces tolerance to the damaging effects of ischemia and prevents cell death in ischemic penumbra. The development of this phenomenon is mediated by mitochondrial adenosine triphosphate-sensitive potassium (KATP+) channels and nitric oxide signaling (NO). The aim of this study was to investigate the dynamics of molecular changes in mitochondria after ischemic preconditioning (IP) and the effect of pharmacological preconditioning (PhP) with the KATP+-channels opener diazoxide on NO levels after ischemic stroke in rats. Immunofluorescence-histochemistry and laser-confocal microscopy were applied to evaluate the cortical expression of electron transport chain enzymes, mitochondrial KATP+-channels, neuronal and inducible NO-synthases, as well as the dynamics of nitrosylation and nitration of proteins in rats during the early and delayed phases of IP. NO cerebral content was studied with electron paramagnetic resonance (EPR) spectroscopy using spin trapping. We found that 24 h after IP in rats, there is a two-fold decrease in expression of mitochondrial KATP+-channels (p = 0.012) in nervous tissue, a comparable increase in expression of cytochrome c oxidase (p = 0.008), and a decrease in intensity of protein S-nitrosylation and nitration (p = 0.0004 and p = 0.001, respectively). PhP led to a 56% reduction of free NO concentration 72 h after ischemic stroke simulation (p = 0.002). We attribute this result to the restructuring of tissue energy metabolism, namely the provision of increased catalytic sites to mitochondria and the increased elimination of NO, which prevents a decrease in cell sensitivity to oxygen during subsequent periods of severe ischemia.
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Affiliation(s)
- Oleg G Deryagin
- Department of Physiology and General Pathology, Medical Faculty, Lomonosov Moscow State UniversityMoscow, Russia
| | - Svetlana A Gavrilova
- Department of Physiology and General Pathology, Medical Faculty, Lomonosov Moscow State UniversityMoscow, Russia
| | - Khalil L Gainutdinov
- Laboratory of Neurorehabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia.,Laboratory of Spin Physics and Spin Chemistry, Zavoisky Physical-Technical Institute of the Russian Academy of SciencesKazan, Russia
| | - Anna V Golubeva
- Department of Physiology and General Pathology, Medical Faculty, Lomonosov Moscow State UniversityMoscow, Russia
| | - Vyatcheslav V Andrianov
- Laboratory of Neurorehabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia.,Laboratory of Spin Physics and Spin Chemistry, Zavoisky Physical-Technical Institute of the Russian Academy of SciencesKazan, Russia
| | - Guzel G Yafarova
- Laboratory of Neurorehabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia.,Laboratory of Spin Physics and Spin Chemistry, Zavoisky Physical-Technical Institute of the Russian Academy of SciencesKazan, Russia
| | - Sergey V Buravkov
- Research Laboratory of Cellular Structure and Tissue Imaging Analysis, Medical Faculty, Lomonosov Moscow State UniversityMoscow, Russia
| | - Vladimir B Koshelev
- Department of Physiology and General Pathology, Medical Faculty, Lomonosov Moscow State UniversityMoscow, Russia
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12
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Phaniraj S, Gao Z, Rane D, Peterson BR. Hydrophobic resorufamine derivatives: potent and selective red fluorescent probes of the endoplasmic reticulum of mammalian cells. DYES AND PIGMENTS : AN INTERNATIONAL JOURNAL 2016; 135:127-133. [PMID: 27765999 PMCID: PMC5066811 DOI: 10.1016/j.dyepig.2016.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The endoplasmic reticulum (ER) of eukaryotic cells plays critical roles in the processing of secreted and transmembrane proteins. Defects in these functions are associated with a wide range of pathologies. To image this organelle, cells are often treated with fluorescent ER-Tracker dyes. Although these compounds are selective, existing red fluorescent probes of the ER are costly glibenclamide derivatives that inhibit ER-associated sulphonylurea receptors. To provide simpler and more cost-effective red fluorescent probes of the ER, we synthesized amino analogues of the fluorophore resorufin. By varying the polarity of linked substituents, we identified hexyl resorufamine (HRA) as a novel hydrophobic (cLogD (pH 7.4) = 3.8) red fluorescent (Ex. 565 nm; Em. 614 nm in ethanol) molecular probe. HRA is exceptionally bright in organic solvents (quantum yield = 0.70), it exclusively localizes to the ER of living HeLa cells as imaged by confocal microscopy, it is effective at concentrations as low as 100 nM, and it is non-toxic under these conditions. To examine its utility, we used HRA to facilitate visualization of small molecule-mediated release of a GFP-GPI fusion protein from the ER into the secretory pathway. HRA represents a potent, selective, and cost-effective probe for imaging and labeling the ER.
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Abstract
KATP channels are integral to the functions of many cells and tissues. The use of electrophysiological methods has allowed for a detailed characterization of KATP channels in terms of their biophysical properties, nucleotide sensitivities, and modification by pharmacological compounds. However, even though they were first described almost 25 years ago (Noma 1983, Trube and Hescheler 1984), the physiological and pathophysiological roles of these channels, and their regulation by complex biological systems, are only now emerging for many tissues. Even in tissues where their roles have been best defined, there are still many unanswered questions. This review aims to summarize the properties, molecular composition, and pharmacology of KATP channels in various cardiovascular components (atria, specialized conduction system, ventricles, smooth muscle, endothelium, and mitochondria). We will summarize the lessons learned from available genetic mouse models and address the known roles of KATP channels in cardiovascular pathologies and how genetic variation in KATP channel genes contribute to human disease.
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Affiliation(s)
- Monique N Foster
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - William A Coetzee
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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Zhou M, Suzuki R, Ishizawa A, Tanaka O, Yasuoka Y, Kanatsu Y, Kawahara K, Abe H. Localization of ATP-sensitive K+ channel subunits in rat pituitary gland . ACTA ACUST UNITED AC 2016. [DOI: 10.1679/aohc.76.53] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University Graduate School of Medicine,
| | - Ryoji Suzuki
- Department of Anatomy, Akita University Graduate School of Medicine,
| | - Akimitsu Ishizawa
- Department of Anatomy, Akita University Graduate School of Medicine,
| | - Osamu Tanaka
- Department of Anatomy, Tokai University School of Medicine,
| | - Yukiko Yasuoka
- Department of Physiology,Kitasato University Graduate School of Medical Sciences,
- Department of Cellular & Molecular Physiology, Kitasato University Graduate School of Medical Sciences,
| | - Yoshinori Kanatsu
- Department of Anatomy, Akita University Graduate School of Medicine,
| | - Katsumasa Kawahara
- Department of Physiology,Kitasato University Graduate School of Medical Sciences,
- Department of Cellular & Molecular Physiology, Kitasato University Graduate School of Medical Sciences,
| | - Hiroshi Abe
- Department of Anatomy, Akita University Graduate School of Medicine,
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Liu Z, Cai H, Dang Y, Qiu C, Wang J. Adenosine triphosphate-sensitive potassium channels and cardiomyopathies (Review). Mol Med Rep 2015; 13:1447-54. [PMID: 26707080 DOI: 10.3892/mmr.2015.4714] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 06/05/2015] [Indexed: 11/06/2022] Open
Abstract
Cardiomyopathies have been indicated to be one of the leading causes of heart failure. Though it was indicated that genetic defects, viral infection and trace element deficiency were among the causes of cardiomyopathy, the etiology has remained to be fully elucidated. Cardiomyocytes require large amounts of energy to maintain their normal biological functions. Adenosine triphosphate-sensitive potassium channels (KATP), composed of inward-rectifier potassium ion channel and sulfonylurea receptor subunits, are present on the cell surface and mitochondrial membrane of cardiac muscle cells. As metabolic sensors sensitive to changes in intracellular energy levels, KATP adapt electrical activities to metabolic challenges, maintaining normal biological functions of myocytes. It is implied that malfunctions, mutations and altered expression of KATP are associated with the pathogenesis of conditions including c hypertrophy, diabetes as well as dilated, ischemic and endemic cardiomyopathy. However, the current knowledge is only the tip of the iceberg and the roles of KATP in cardiomyopathies largely remain to be elucidated in future studies.
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Affiliation(s)
- Zhongwei Liu
- Department of Cardiology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - Hui Cai
- Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yonghui Dang
- College of Medicine and Forensics, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710061, P.R. China
| | - Chuan Qiu
- Department of Biostatistics and Bioinformatics, School of Public Health and Tropical Medicine, Tulane University, New Orleans 70112‑2705, LA, USA
| | - Junkui Wang
- Department of Cardiology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China
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Jovanović S, Ballantyne T, Du Q, Blagojević M, Jovanović A. Phenylephrine preconditioning in embryonic heart H9c2 cells is mediated by up-regulation of SUR2B/Kir6.2: A first evidence for functional role of SUR2B in sarcolemmal KATP channels and cardioprotection. Int J Biochem Cell Biol 2015; 70:23-8. [PMID: 26556311 PMCID: PMC4711337 DOI: 10.1016/j.biocel.2015.10.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 10/22/2015] [Accepted: 10/30/2015] [Indexed: 02/07/2023]
Abstract
ATP-sensitive K+ (KATP) channels were originally described in cardiomyocytes, where physiological levels of intracellular ATP keep them in a closed state. Structurally, these channels are composed of pore-forming inward rectifier, Kir6.1 or Kir6.2, and a regulatory, ATP-binding subunit, SUR1, SUR2A or SUR2B. SUR1 and Kir6.2 form pancreatic type of KATP channels, SUR2A and Kir6.2 form cardiac type of KATP channels, SUR2B and Kir6.1 form vascular smooth muscle type of KATP channels. The presence of SUR2B has been described in cardiomyocytes, but its functional significance and role has remained unknown. Pretreatment with phenylephrine (100 nM) for 24 h increased mRNA levels of SUR2B and Kir6.2, without affecting those levels of SUR1, SUR2A and Kir6.1 in embryonic heart H9c2 cells. Such increase was associated with increased K+ current through KATP channels and Kir6.2/SUR2B protein complexes as revealed by whole cell patch clamp electrophysiology and immunoprecipitation/Western blotting respectively. Pretreatment with phenylephrine (100 nM) generated a cellular phenotype that acquired resistance to chemical hypoxia induced by 2,4-dinitrophenol (DNP; 10 mM), which was accompanied by increased in K+ current in response to DNP (10 mM). Cytoprotection afforded by phenylephrine (100 nM) was abolished by infection of H9c2 cells with adenovirus containing Kir6.2AFA, a mutant form of Kir6.2 with largely reduced K+ conductance. Taking all together, the present findings demonstrate that the activation of α1-adrenoceptors up-regulates SUR2B/Kir6.2 to confer cardioprotection. This is the first account of possible physiological role of SUR2B in cardiomyocytes.
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Affiliation(s)
- Sofija Jovanović
- Medical Research Institute, Division of Cardiovascular & Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, UK
| | - Thomas Ballantyne
- Medical Research Institute, Division of Cardiovascular & Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, UK
| | - Qingyou Du
- Medical Research Institute, Division of Cardiovascular & Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, UK
| | - Miloš Blagojević
- Department of Anatomy, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia
| | - Aleksandar Jovanović
- Medical Research Institute, Division of Cardiovascular & Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, UK.
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Ujike A, Otsuguro KI, Miyamoto R, Yamaguchi S, Ito S. Bidirectional effects of hydrogen sulfide via ATP-sensitive K+ channels and transient receptor potential A1 channels in RIN14B cells. Eur J Pharmacol 2015; 764:463-470. [DOI: 10.1016/j.ejphar.2015.07.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 07/09/2015] [Accepted: 07/10/2015] [Indexed: 12/22/2022]
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Molecular analysis of ATP-sensitive K(+) channel subunits expressed in mouse portal vein. Vascul Pharmacol 2015; 75:29-39. [PMID: 26163942 DOI: 10.1016/j.vph.2015.06.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/16/2015] [Accepted: 06/29/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND Several combinations of inwardly rectifying K(+) channel 6.x family pore-forming (KIR6.x) subunits associated with sulphonylurea receptor (SUR.x) subunits have been detected among ATP-sensitive K(+) (KATP) channels. It remains to be established which of these is expressed in native vascular smooth muscle. METHODS Pharmacological and electrophysiological properties of KATP channels in mouse portal vein were investigated using tension measurements and patch-clamp techniques. Molecular biological analyses were also performed to investigate the structural properties of these channels. RESULTS Spontaneous contractions in mouse portal vein were reversibly reduced by pinacidil and MCC-134, and the pinacidil-induced relaxation was antagonized by glibenclamide and U-37883A. In cell-attached mode, pinacidil activated glibenclamide-sensitive K(+) channels with a conductance (35 pS) similar to that of KIR6.1. RT-PCR analysis revealed the expression of KIR6.1, KIR6.2 and SUR2B transcripts. Using real-time PCR methods, the quantitative expression of KIR6.1 was much greater than that of KIR6.2. Immunohistochemical studies indicated the presence of KIR6.1 and SUR2B proteins in the smooth muscle layers of mouse portal vein and in single smooth muscle cells dispersed from mouse portal vein. CONCLUSIONS The results indicate that native KATP channels in mouse portal vein are likely to be composed of a heterocomplex of KIR6.1 and SUR2B subunits.
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Iwasa K, Zhu HL, Shibata A, Maehara Y, Teramoto N. Molecular analysis of ATP-sensitive K⁺ channel subunits expressed in mouse vas deferens myocytes. Br J Pharmacol 2014; 171:145-57. [PMID: 24117345 DOI: 10.1111/bph.12437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 09/10/2013] [Accepted: 09/13/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE ATP-sensitive K(+)(K(ATP)) channels, which are composed of K(IR)6.x associated with sulphonylurea receptor (SUR) subunits, have been detected in native smooth muscle cells, but it is currently not known which of these is expressed in mouse vas deferens myocytes. EXPERIMENTAL APPROACH Pharmacological and electrophysiological properties of K(ATP) channels in mouse vas deferens myocytes were investigated using patch clamp techniques. Molecular biological analyses were performed to examine the properties of these K(ATP) channels. KEY RESULTS During conventional whole-cell recording, pinacidil elicited an inward current that was suppressed by glibenclamide, a sulfonylurea agent, and by U-37883A, a selective K(IR)6.1 blocker. When 0.3 mM ATP was added to the pipette solution, the peak amplitude of the pinacidil-induced current was much smaller than that recorded in its absence. When 3 mM UDP, GDP or ADP was included in the pipette solution, an inward current was elicited after establishment of the conventional whole-cell configuration, with potency order being UDP > GDP > ADP. These nucleoside diphosphate-induced inward currents were suppressed by glibenclamide. MCC-134, a SUR modulator, induced glibenclamide-sensitive K(ATP) currents that were similar to those induced by 100 μM pinacidil. In the cell-attached configuration, pinacidil activated channels with a conductance similar to that of K(IR)6.1. Reverse transcription PCR analysis revealed the expression of K(IR)6.1 and SUR2B transcripts and immunohistochemical studies indicated the presence of K(IR)6.1 and SUR2B proteins in the myocytes. CONCLUSIONS AND IMPLICATIONS Our results indicate that native K(ATP) channels in mouse vas deferens myocytes are a heterocomplex of K(IR)6.1 channels and SUR2B subunits.
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Affiliation(s)
- Kazuomi Iwasa
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Pouokam E, Bader S, Brück B, Schmidt B, Diener M. ATP-sensitive K(+) channels in rat colonic epithelium. Pflugers Arch 2012; 465:865-77. [PMID: 23262522 DOI: 10.1007/s00424-012-1207-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 12/10/2012] [Accepted: 12/10/2012] [Indexed: 11/30/2022]
Abstract
ATP-sensitive K(+) (KATP) channels couple the metabolic state of a cell to its electrical activity. They consist of a hetero-octameric complex with pore-forming Kir6.x (Kir6.1, Kir6.2) and regulatory sulfonylurea receptor (SUR) subunits. Functional data indicate that KATP channels contribute to epithelial K(+) currents at colonic epithelia. However, their molecular identity and their properties are largely unknown. Therefore, changes in short-circuit current (I sc) induced by the KATP channel opener pinacidil (5 10(-4) mol l(-1)) were measured in Ussing chambers under control conditions and in the presence of different blockers of KATP channels. The channel subunits expressed by the colonic epithelium were identified by immunohistochemistry and by RT-PCR. The K(+) channel opener, when administered at the serosal side, induced an increase in I sc consistent with the induction of transepithelial Cl(-) secretion after activation of basolateral K(+) channels, whereas mucosal administration of pinacidil resulted in a negative I sc. The increase in I sc evoked by serosal pinacidil was inhibited by serosal administration of glibenclamide (5 10(-4) mol l(-1)) and gliclazide (10(-6) mol l(-1)), but was resistant even against a high concentration (10(-2) mol l(-1)) of tolbutamide. In contrast, none of these inhibitors (administered at the mucosal side) reduced significantly the negative I sc induced by mucosal pinacidil. Instead, pinacidil inhibited Cl(-) currents across apical Cl(-) channels in basolaterally depolarized epithelia indicating that the negative I sc induced by mucosal pinacidil is due to a transient inhibition of Cl(-) secretion. In mRNA prepared from isolated colonic crypts, messenger RNA for both pore-forming subunits, Kir6.1 and Kir6.2, and two regulatory subunits (SUR1 and SUR2B) was found. Expression within the colonic epithelium was confirmed for these subunits by immunohistochemistry. In consequence, KATP channels are present in the basolateral membrane of the colonic epithelium; their exact subunit composition, however, has still to be revealed.
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Affiliation(s)
- Ervice Pouokam
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University, Frankfurter Str. 100, Giessen, Germany
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Hirose M, Takeishi Y, Nakada T, Shimojo H, Kashihara T, Nishio A, Suzuki S, Mende U, Matsumoto K, Matsushita N, Taira E, Sato F, Yamada M. Nicorandil prevents Gαq-induced progressive heart failure and ventricular arrhythmias in transgenic mice. PLoS One 2012; 7:e52667. [PMID: 23285142 PMCID: PMC3527603 DOI: 10.1371/journal.pone.0052667] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 11/19/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Beneficial effects of nicorandil on the treatment of hypertensive heart failure (HF) and ischemic heart disease have been suggested. However, whether nicorandil has inhibitory effects on HF and ventricular arrhythmias caused by the activation of G protein alpha q (Gα(q)) -coupled receptor (GPCR) signaling still remains unknown. We investigated these inhibitory effects of nicorandil in transgenic mice with transient cardiac expression of activated Gα(q) (Gα(q)-TG). METHODOLOGY/PRINCIPAL FINDINGS Nicorandil (6 mg/kg/day) or vehicle was chronically administered to Gα(q)-TG from 8 to 32 weeks of age, and all experiments were performed in mice at the age of 32 weeks. Chronic nicorandil administration prevented the severe reduction of left ventricular fractional shortening and inhibited ventricular interstitial fibrosis in Gα(q)-TG. SUR-2B and SERCA2 gene expression was decreased in vehicle-treated Gα(q)-TG but not in nicorandil-treated Gα(q)-TG. eNOS gene expression was also increased in nicorandil-treated Gα(q)-TG compared with vehicle-treated Gα(q)-TG. Electrocardiogram demonstrated that premature ventricular contraction (PVC) was frequently (more than 20 beats/min) observed in 7 of 10 vehicle-treated Gα(q)-TG but in none of 10 nicorandil-treated Gα(q)-TG. The QT interval was significantly shorter in nicorandil-treated Gα(q)-TG than vehicle-treated Gα(q)-TG. Acute nicorandil administration shortened ventricular monophasic action potential duration and reduced the number of PVCs in Langendorff-perfused Gα(q)-TG mouse hearts. Moreover, HMR1098, a blocker of cardiac sarcolemmal K(ATP) channels, significantly attenuated the shortening of MAP duration induced by nicorandil in the Gα(q)-TG heart. CONCLUSIONS/SIGNIFICANCE These findings suggest that nicorandil can prevent the development of HF and ventricular arrhythmia caused by the activation of GPCR signaling through the shortening of the QT interval, action potential duration, the normalization of SERCA2 gene expression. Nicorandil may also improve the impaired coronary circulation during HF.
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Affiliation(s)
- Masamichi Hirose
- Department of Molecular and Cellular Pharmacology, Iwate Medical University School of Pharmaceutical Sciences, Shiwa, Iwate, Japan.
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Zhou M, He HJ, Tanaka O, Sekiguchi M, Kawahara K, Abe H. Localization of the ATP-sensitive K(+) channel regulatory subunits SUR2A and SUR2B in the rat brain. Neurosci Res 2012; 74:91-105. [PMID: 22960600 DOI: 10.1016/j.neures.2012.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Revised: 08/22/2012] [Accepted: 08/23/2012] [Indexed: 01/11/2023]
Abstract
ATP-sensitive K(+) (K(ATP)) channel subunits SUR2A and SUR2B in the rat brain were investigated by RT-PCR assay, western blot analysis, in situ hybridization histochemistry, and immunohistochemical staining. The results show that the mRNA and protein of SUR2A and SUR2B are expressed in whole rat brain extracts and selected regions. SUR2 mRNA is widely expressed in many neurons and glial cells as revealed by in situ hybridization histochemistry. Immunohistochemical staining shows SUR2A to be widely expressed in neurons of the brain, especially in the large pyramidal neurons and their main dendrites in the neocortex and in the Purkinje cells of the cerebellar cortex. In contrast to SUR2A, SUR2B is potently expressed in small cells in the corpus callosum and cerebellar white matter, but is also weakly expressed in some neurons. Double immunostaining shows SUR2B to be localized in astrocytes and oligodendrocytes, while SUR2A is only localized in oligodendrocytes. These results suggest that SUR2A might be mainly a regulatory subunit of the K(ATP) channel in most neurons and part of oligodendrocytes, while SUR2B might be mainly a regulatory subunit of the K(ATP) channel in astrocytes, oligodendrocytes, and some neurons.
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Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University Graduate School of Medicine and Faculty of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
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Kefaloyianni E, Bao L, Rindler MJ, Hong M, Patel T, Taskin E, Coetzee WA. Measuring and evaluating the role of ATP-sensitive K+ channels in cardiac muscle. J Mol Cell Cardiol 2012; 52:596-607. [PMID: 22245446 DOI: 10.1016/j.yjmcc.2011.12.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Revised: 12/06/2011] [Accepted: 12/23/2011] [Indexed: 11/27/2022]
Abstract
Since ion channels move electrical charge during their activity, they have traditionally been studied using electrophysiological approaches. This was sometimes combined with mathematical models, for example with the description of the ionic mechanisms underlying the initiation and propagation of action potentials in the squid giant axon by Hodgkin and Huxley. The methods for studying ion channels also have strong roots in protein chemistry (limited proteolysis, the use of antibodies, etc.). The advent of the molecular cloning and the identification of genes coding for specific ion channel subunits in the late 1980s introduced a multitude of new techniques with which to study ion channels and the field has been rapidly expanding ever since (e.g. antibody development against specific peptide sequences, mutagenesis, the use of gene targeting in animal models, determination of their protein structures) and new methods are still in development. This review focuses on techniques commonly employed to examine ion channel function in an electrophysiological laboratory. The focus is on the K(ATP) channel, but many of the techniques described are also used to study other ion channels.
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Ahrén B. Are sulfonylureas less desirable than DPP-4 inhibitors as add-on to metformin in the treatment of type 2 diabetes? Curr Diab Rep 2011; 11:83-90. [PMID: 21243448 DOI: 10.1007/s11892-011-0179-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Sulfonylureas (SUs) are commonly used as add-on to metformin in treatment of type 2 diabetes in patients who are insufficiently controlled by metformin alone. They have good efficacy and have been shown to prevent microvascular complications. However, treatment with SUs is also associated with a high frequency of hypoglycemia, increased body weight, and a high risk of secondary failure. During recent years, dipeptidyl peptidase-4 (DPP-4) inhibitors have emerged as alternatives to SUs. They show similar efficacy as SUs but with lower risk of hypoglycemia, and reduction or no change in body weight, and if confirmed in humans, they may preserve islet function and thereby minimize the risk for secondary failure. Their limitation at present is the lack of long-term (>5 years) experience on durability and safety. Overall, therefore, the conclusion emerges that SUs are less desirable than DPP-4 inhibitors in management of hyperglycemia in type 2 diabetes.
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Affiliation(s)
- Bo Ahrén
- Department of Clinical Sciences Lund, Lund University, B11 BMC, SE-221 84, Lund, Sweden.
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Zhou M, He HJ, Tanaka O, Sekiguchi M, Kawahara K, Abe H. Different Localization of ATP Sensitive K+ Channel Subunits in Rat Testis. Anat Rec (Hoboken) 2011; 294:729-37. [DOI: 10.1002/ar.21348] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 12/16/2010] [Accepted: 12/19/2010] [Indexed: 01/21/2023]
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Ploug KB, Baun M, Hay-Schmidt A, Olesen J, Jansen-Olesen I. Presence and vascular pharmacology of KATP channel subtypes in rat central and peripheral tissues. Eur J Pharmacol 2010; 637:109-17. [PMID: 20361954 DOI: 10.1016/j.ejphar.2010.03.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 02/23/2010] [Accepted: 03/14/2010] [Indexed: 11/25/2022]
Abstract
K(ATP) channel openers are vasodilators and induce headache in normal subjects. We previously identified the Kir6.1/SUR2B K(ATP) channel subtype in major cerebral and dural arteries of rat, pig and man. We hypothesized that craniovascular Kir6.1/SUR2B K(ATP) channels mediate the headache-inducing effects of K(ATP) channel openers and that a Kir6.1/SUR2B specific blocker might be effective in the treatment of primary headaches such as migraine. Since K(ATP) channels are ubiquitous, we characterized the K(ATP) channel subtypes in major rat cranial and peripheral arteries and organs in order to understand the possible adverse effects of a Kir6.1/SUR2B blocker. We studied the mRNA expression of K(ATP) channel subunits in rat femoral, mesenteric, renal, coronary, basilar, middle cerebral and middle meningeal arteries and in tissue from rat heart, brain, liver, colon, lung, kidney and pancreas. We also studied the effects and potencies of a panel of synthetic K(ATP) channel openers and their potential inhibition by the Kir6.1 subunit-specific K(ATP) channel blocker PNU-37883A in segments of the arteries mounted in a wire myograph. Our studies suggest that Kir6.1/SUR2B forms the major functional K(ATP) channel complex in rat cranial and peripheral arteries. The mRNA transcripts of SUR1 and Kir6.2 subunits were predominantly found in brain, pancreas and heart, while SUR2A mRNA was merely detected within the heart. K(ATP) channel blockers highly specific for the SUR2B subunit may have no adverse CNS and cardiac effects and will not affect insulin release in the pancreas. However, a SUR2B blocker may not discriminate between cranial and peripheral arteries.
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Affiliation(s)
- Kenneth Beri Ploug
- Department of Neurology, Glostrup Hospital, Faculty of Health Sciences, University of Copenhagen, Denmark
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Zhou M, He HJ, Hirano M, Sekiguchi M, Tanaka O, Kawahara K, Abe H. Localization of ATP-sensitive K+ channel subunits in rat submandibular gland. J Histochem Cytochem 2009; 58:499-507. [PMID: 19934381 DOI: 10.1369/jhc.2009.955047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ATP-sensitive K(+) (K(ATP)) channel subunits were investigated in rat submandibular gland (SMG). RT-PCR detected the presence of mRNA transcripts of the Kir6.1, Kir6.2, SUR2A, and SUR2B in the SMG, whereas SUR1 mRNA was barely detected. Western blot analysis provided the evidence that these four K(ATP) channel subunits are expressed in rat SMG. Immunostaining detected that these four K(ATP) channel subunits are widely distributed, with different intensities, in myoepithelial cells, epithelial cells of intercalated ducts, granular convoluted tubules, striated ducts, and excretory ducts. Immunofluorescence double staining showed that Kir6.1 and Kir6.2 colocalized with SUR2A in the myoepithelial cells, granular convoluted tubules, striated ducts, and excretory ducts. Kir6.1 and Kir6.2 also colocalized with SUR2B, mainly in the duct system, e.g., the granular convoluted tubules, striated ducts, and excretory ducts. Taken together, these results indicate that the K(ATP) channels in SMG may consist of Kir6.1, Kir6.2, SUR2A, and SUR2B, with various combinations of colocalization with each other, and may play important roles in rat SMG during salivary secretion.
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Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University Graduate School of Medicine and Faculty of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
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Zoratti M, De Marchi U, Gulbins E, Szabò I. Novel channels of the inner mitochondrial membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1787:351-63. [PMID: 19111672 DOI: 10.1016/j.bbabio.2008.11.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 11/24/2008] [Accepted: 11/26/2008] [Indexed: 12/15/2022]
Abstract
Along with a large number of carriers, exchangers and "pumps", the inner mitochondrial membrane contains ion-conducting channels which endow it with controlled permeability to small ions. Some have been shown to be the mitochondrial counterpart of channels present also in other cellular membranes. The manuscript summarizes the current state of knowledge on the major inner mitochondrial membrane channels, properties, identity and proposed functions. Considerable attention is currently being devoted to two K(+)-selective channels, mtK(ATP) and mtBK(Ca). Their activation in "preconditioning" is considered by many to underlie the protection of myocytes and other cells against subsequent ischemic damage. We have recently shown that in apoptotic lymphocytes inner membrane mtK(V)1.3 interacts with the pro-apoptotic protein Bax after the latter has inserted into the outer mitochondrial membrane. Whether the just-discovered mtIK(Ca) has similar cellular role(s) remains to be seen. The Ca(2+) "uniporter" has been characterized electrophysiologically, but still awaits a molecular identity. Chloride-selective channels are represented by the 107 pS channel, the first mitochondrial channel to be observed by patch-clamp, and by a approximately 400 pS pore we have recently been able to fully characterize in the inner membrane of mitochondria isolated from a colon tumour cell line. This we propose to represent a component of the Permeability Transition Pore. The available data exclude the previous tentative identification with porin, and indicate that it coincides instead with the still molecularly unidentified "maxi" chloride channel.
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Lybaert P, Vanbellinghen AM, Quertinmont E, Petein M, Meuris S, Lebrun P. KATP Channel Subunits Are Expressed in the Epididymal Epithelium in Several Mammalian Species1. Biol Reprod 2008; 79:253-61. [DOI: 10.1095/biolreprod.107.064659] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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30
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Zhou M, He HJ, Tanaka O, Suzuki R, Sekiguchi M, Yasuoka Y, Kawahara K, Itoh H, Abe H. Localization of the sulphonylurea receptor subunits, SUR2A and SUR2B, in rat renal tubular epithelium. TOHOKU J EXP MED 2008; 214:247-56. [PMID: 18323694 DOI: 10.1620/tjem.214.247] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
ATP-sensitive K+ (K(ATP)) channels in the kidney are considered to play roles in regulating membrane potential according to changes in the intracellular ATP concentration. They are composed of two types of subunits; the pore subunits (Kir6.1, Kir6.2), which are members of the inwardly rectifying K+ channel family, and the regulatory subunits, the sulphonylurea receptors, which belong to the ATP-binding cassette (ABC) superfamily. The sulphonylurea receptors (SURs) are receptors of sulphonylureas widely used for the treatment of type 2 diabetes mellitus. The SURs are divided into two isoforms, SUR1 and SUR2, the latter was further divided into SUR2A and SUR2B. In the present study, we have investigated the mRNA expression by RT-PCR assay, and protein expression profiles by immunoblotting, immunohistochemistry, and immunoelectron microscopy with anti SUR2A and anti SUR2B antibodies. RT-PCR detected the presence of mRNA transcripts of the SUR2A and SUR2B, while SUR1 mRNA was barely detected. In immunoblotting, SUR2A protein was detected distinctly in the microsomal fraction, weakly in the mitochondrial fraction and at negligible level in the cell membrane fraction. In contrast, the SUR2B protein was detected intensely in the microsomal fraction, with a low level in the mitochondrial fraction and scarcely in the cell membrane fraction. In immunohistochemistry SUR2A and SUR2B proteins were widely distributed in renal tubular epithelial cells, glomerular mesangial cells, and the endothelium and the smooth muscle of blood vessels. In immunoelectron microscopy, the immunoreactivity was localized in the endoplasmic reticulum and mitochondria throughout the epithelial cells for SUR2A, and dominantly in the apical cytoplasm of the cells for SUR2B. In conclusion, the regulatory subunits of the K(ATP) channel in the rat kidney are SUR2A and SUR2B; they also are candidate regulatory subunits for the mitochondrial K(ATP) channel.
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Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University School of Medicine.
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Burke MA, Mutharasan RK, Ardehali H. The Sulfonylurea Receptor, an Atypical ATP-Binding Cassette Protein, and Its Regulation of the KATPChannel. Circ Res 2008; 102:164-76. [DOI: 10.1161/circresaha.107.165324] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Michael A. Burke
- From the Division of Cardiology, Feinberg Cardiovascular Institute, Northwestern University, Chicago, Ill
| | - R. Kannan Mutharasan
- From the Division of Cardiology, Feinberg Cardiovascular Institute, Northwestern University, Chicago, Ill
| | - Hossein Ardehali
- From the Division of Cardiology, Feinberg Cardiovascular Institute, Northwestern University, Chicago, Ill
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