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Franco-Obregón A. Harmonizing Magnetic Mitohormetic Regenerative Strategies: Developmental Implications of a Calcium-Mitochondrial Axis Invoked by Magnetic Field Exposure. Bioengineering (Basel) 2023; 10:1176. [PMID: 37892906 PMCID: PMC10604793 DOI: 10.3390/bioengineering10101176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/05/2023] [Accepted: 10/08/2023] [Indexed: 10/29/2023] Open
Abstract
Mitohormesis is a process whereby mitochondrial stress responses, mediated by reactive oxygen species (ROS), act cumulatively to either instill survival adaptations (low ROS levels) or to produce cell damage (high ROS levels). The mitohormetic nature of extremely low-frequency electromagnetic field (ELF-EMF) exposure thus makes it susceptible to extraneous influences that also impinge on mitochondrial ROS production and contribute to the collective response. Consequently, magnetic stimulation paradigms are prone to experimental variability depending on diverse circumstances. The failure, or inability, to control for these factors has contributed to the existing discrepancies between published reports and in the interpretations made from the results generated therein. Confounding environmental factors include ambient magnetic fields, temperature, the mechanical environment, and the conventional use of aminoglycoside antibiotics. Biological factors include cell type and seeding density as well as the developmental, inflammatory, or senescence statuses of cells that depend on the prior handling of the experimental sample. Technological aspects include magnetic field directionality, uniformity, amplitude, and duration of exposure. All these factors will exhibit manifestations at the level of ROS production that will culminate as a unified cellular response in conjunction with magnetic exposure. Fortunately, many of these factors are under the control of the experimenter. This review will focus on delineating areas requiring technical and biological harmonization to assist in the designing of therapeutic strategies with more clearly defined and better predicted outcomes and to improve the mechanistic interpretation of the generated data, rather than on precise applications. This review will also explore the underlying mechanistic similarities between magnetic field exposure and other forms of biophysical stimuli, such as mechanical stimuli, that mutually induce elevations in intracellular calcium and ROS as a prerequisite for biological outcome. These forms of biophysical stimuli commonly invoke the activity of transient receptor potential cation channel classes, such as TRPC1.
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Affiliation(s)
- Alfredo Franco-Obregón
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; ; Tel.: +65-6777-8427 or +65-6601-6143
- Institute of Health Technology and Innovation (iHealthtech), National University of Singapore, Singapore 117599, Singapore
- Biolonic Currents Electromagnetic Pulsing Systems Laboratory (BICEPS), National University of Singapore, Singapore 117599, Singapore
- NUS Centre for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- Nanomedicine Translational Research Programme, Centre for NanoMedicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117544, Singapore
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Baskaran P, Mohandass A, Gustafson N, Bennis J, Louis S, Alexander B, Nemenov MI, Thyagarajan B, Premkumar LS. Evaluation of a polymer-coated nanoparticle cream formulation of resiniferatoxin for the treatment of painful diabetic peripheral neuropathy. Pain 2023; 164:782-790. [PMID: 36001079 PMCID: PMC9950295 DOI: 10.1097/j.pain.0000000000002765] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/10/2022] [Indexed: 02/02/2023]
Abstract
ABSTRACT Painful diabetic peripheral neuropathy (PDPN) is one of the major complications of diabetes. Currently, centrally acting drugs and topical analgesics are used for treating PDPN. These drugs have adverse effects; some are ineffective, and treatment with opioids is associated with use dependence and addiction. Recent research indicates that transient receptor potential vanilloid 1 (TRPV1) expressed in the peripheral sensory nerve terminals is an emerging target to treat pain associated with PDPN. Block of TRPV1 ion channel with specific antagonists, although effective as an analgesic, induced hyperthermia in clinical trials. However, TRPV1 agonists are useful to treat pain by virtue of their ability to cause Ca 2+ influx and subsequently leading to nerve terminal desensitization. Here, we report the effectiveness of an ultrapotent TRPV1 agonist, resiniferatoxin (RTX) nanoparticle, in a topical formulation (RTX-cream; RESINIZIN) that alleviates pain associated with DPN in animal models of diabetes. Resiniferatoxin causes nerve terminal depolarization block in the short term, which prevents pain during application and leading to nerve terminal desensitization/depletion in the long term resulting in long-lasting pain relief. Application of RTX cream to the hind limbs suppresses thermal hyperalgesia in streptozotocin-induced diabetic rats and mini pigs without any adverse effects as compared with capsaicin at therapeutic doses, which induces intense pain during application. Resiniferatoxin cream also decreases the expression of TRPV1 in the peripheral nerve endings and suppresses TRPV1-mediated calcitonin gene-related peptide release in the skin samples of diabetic rats and mini pigs. Our preclinical data confirm that RTX topical formulation is an effective treatment option for PDPN.
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Affiliation(s)
- Padmamalini Baskaran
- School of Pharmacy, University of Wyoming, Laramie, WY, USA
- Ion Channel, Pharmacology LLC, Springfield, IL, USA
| | | | - Noah Gustafson
- School of Pharmacy, University of Wyoming, Laramie, WY, USA
| | - Jane Bennis
- School of Pharmacy, University of Wyoming, Laramie, WY, USA
| | - Somaja Louis
- Department of Pharmacology, Southern Illinois University, Springfield, IL
| | | | - Mikhail I. Nemenov
- Department of Anesthesia, Stanford University, Palo Alto, CA, USA
- LasMed LLC, Mountain View, CA, USA
| | | | - Louis S. Premkumar
- Department of Pharmacology, Southern Illinois University, Springfield, IL
- Ion Channel, Pharmacology LLC, Springfield, IL, USA
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3
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Nam A, Quarshie S, Kimble M, Hessinger DA. Functional Characterization of TRPV-Like Ion Channels Involved in Nematocyst Discharge from the Sea Anemone Diadumene lineata. THE BIOLOGICAL BULLETIN 2022; 242:48-61. [PMID: 35245164 DOI: 10.1086/717902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
AbstractCnidarians require mechanical stimuli to trigger nematocyst discharge and initiate feeding behaviors. The interval from triggering stimulus to response is tens of microseconds, making it likely that mechanically gated ion channels trigger nematocyst discharge. Because many transient receptor potential channels are mechanically gated, we hypothesized that nematocyst discharge involves transient receptor potential channels. We therefore tested various transient receptor potential channel inhibitors to determine whether they inhibit nematocyst discharge and prey killing in the acontiate sea anemone (Actinaria) Diadumene lineata (a.k.a. Haliplanella luciae). Three types of cnidocyte supporting cell complexes regulate nematocyst discharge in anemones: Types C, B, and A. Discharge from Type Cs is directly triggered by stimulation of contact-sensitive mechanoreceptors, while Type Bs require activation of chemoreceptors from prey-derived N-acetylated sugars to sensitize contact-sensitive mechanoreceptors. In Type As, activated chemoreceptors tune vibration-sensitive mechanoreceptors that predispose contact-sensitive mechanoreceptors for triggering. The non-selective transient receptor potential channel blockers lanthanum and gadolinium dose-dependently inhibited about 80% of prey killing and all nematocyst discharge from Type Bs and Type Cs, but not Type As. The selective transient receptor potential vanilloid 4 (TRPV4) blocker GSK2193874 inhibited Type As and Type Bs. However, the selective TRPV4 blockers HC-067047 and RN-1734 inhibited only Type As. Thus, three TRPV4-selective blockers implicate TRPV-like involvement in discharge from Type As, whereas GSK2193874 also affected Type Bs. Our results suggest that a TRPV-like homolog plays an essential role in nematocyst-mediated prey killing from Type As, whereas other transient receptor potential channels are likely involved in discharge from Type B and C cnidocyte supporting cell complexes.
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S100A4 plays a key role in TRPV3 ion channel expression and its electrophysiological function. Neurosci Lett 2021; 759:135999. [PMID: 34058292 DOI: 10.1016/j.neulet.2021.135999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/27/2021] [Accepted: 05/25/2021] [Indexed: 01/07/2023]
Abstract
Transient receptor potential vanilloid 3 (TRPV3), a non-selective cation ion channel, is regulated by small molecules such as Ca2+ and calmodulin (CaM). Together with S100A4 (S100 calcium-binding protein family), is critical in cell proliferation and progression. Although TRPV3 has been proved to play a role in Ca2+ regulation and participate in Ca2+-related cellular processes, its molecular mechanism remains unclear. In this study, we found that TRPV3 and S100A4 were co-expressed in the same region of the cell, and surprisingly, the protein expression level of TRPV3 significantly increased with the overexpression of S100A4. Moreover, co-immunoprecipitation results showed that these two proteins could bind with each other. Functionally, we found that when S100A4 was simultaneously expressed in cells, more Ca2+ would be transferred into the cells through the TRPV3 ion channel. Consistent with Ca2+ regulation results, electrophysiological recordings demonstrated that S100A4 improved the function of TRPV3 in ions' flux, suggesting that the S100A4 could bind with TRPV3 and simultaneously promoted its expression, thus affecting its functions on related ions' flux. Our findings identified the link between S100A4 and TRPV3 and provided a novel molecular mechanism for TRPV3 regulation.
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Modulation of TRPV1 channel function by natural products in the treatment of pain. Chem Biol Interact 2020; 330:109178. [DOI: 10.1016/j.cbi.2020.109178] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 05/22/2020] [Accepted: 06/09/2020] [Indexed: 01/01/2023]
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Morán-Zendejas R, Delgado-Ramírez M, Xu J, Valdés-Abadía B, Aréchiga-Figueroa IA, Cui M, Rodríguez-Menchaca AA. In vitro and in silico characterization of the inhibition of Kir4.1 channels by aminoglycoside antibiotics. Br J Pharmacol 2020; 177:4548-4560. [PMID: 32726456 DOI: 10.1111/bph.15214] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 06/11/2020] [Accepted: 07/15/2020] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Aminoglycoside antibiotics are positively charged molecules that are known to inhibit several ion channels. In this study, we have shown that aminoglycosides also inhibit the activity of Kir4.1 channels. Aminoglycosides inhibit Kir4.1 channels by a pore-blocking mechanism, plugging the central vestibule of the channel. EXPERIMENTAL APPROACH Patch-clamp recordings were made in HEK-293 cells transiently expressing Kir4.1 channels to analyse the effects of gentamicin, neomycin and kanamycin. In silico modelling followed by mutagenesis were realized to identify the residues critical for aminoglycosides binding to Kir4.1. KEY RESULTS Aminoglycoside antibiotics block Kir4.1 channels in a concentration- and voltage-dependent manner, getting access to the protein from the intracellular side of the plasma membrane. Aminoglycosides block Ki4.1 with a rank order of potency as follows: gentamicin ˃ neomycin ˃ kanamycin. The residues T128 and principally E158, facing the central cavity of Kir4.1, are important structural determinants for aminoglycosides binding to the channel, as determined by our in silico modelling and confirmed by mutagenesis experiments. CONCLUSION AND IMPLICATIONS Kir4.1 channels are also target of aminoglycoside antibiotics, which could affect potassium transport in several tissues.
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Affiliation(s)
- Rita Morán-Zendejas
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | - Mayra Delgado-Ramírez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | - Jie Xu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA
| | - Belkis Valdés-Abadía
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | | | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA
| | - Aldo A Rodríguez-Menchaca
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
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Osmakov DI, Khasanov TA, Andreev YA, Lyukmanova EN, Kozlov SA. Animal, Herb, and Microbial Toxins for Structural and Pharmacological Study of Acid-Sensing Ion Channels. Front Pharmacol 2020; 11:991. [PMID: 32733241 PMCID: PMC7360831 DOI: 10.3389/fphar.2020.00991] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 06/19/2020] [Indexed: 12/22/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are of the most sensitive molecular sensors of extracellular pH change in mammals. Six isoforms of these channels are widely represented in membranes of neuronal and non-neuronal cells, where these molecules are involved in different important regulatory functions, such as synaptic plasticity, learning, memory, and nociception, as well as in various pathological states. Structural and functional studies of both wild-type and mutant ASICs are essential for human care and medicine for the efficient treatment of socially significant diseases and ensure a comfortable standard of life. Ligands of ASICs serve as indispensable tools for these studies. Such bioactive compounds can be synthesized artificially. However, to date, the search for such molecules has been most effective amongst natural sources, such as animal venoms or plants and microbial extracts. In this review, we provide a detailed and comprehensive structural and functional description of natural compounds acting on ASICs, as well as the latest information on structural aspects of their interaction with the channels. Many of the examples provided in the review demonstrate the undoubted fundamental and practical successes of using natural toxins. Without toxins, it would not be possible to obtain data on the mechanisms of ASICs' functioning, provide detailed study of their pharmacological properties, or assess the contribution of the channels to development of different pathologies. The selectivity to different isoforms and variety in the channel modulation mode allow for the appraisal of prospective candidates for the development of new drugs.
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Affiliation(s)
- Dmitry I. Osmakov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, Russia
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Timur A. Khasanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, Russia
| | - Yaroslav A. Andreev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, Russia
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Ekaterina N. Lyukmanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, Russia
| | - Sergey A. Kozlov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, Russia
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Huang R, Wang F, Yang Y, Ma W, Lin Z, Cheng N, Long Y, Deng S, Li Z. Recurrent activations of transient receptor potential vanilloid-1 and vanilloid-4 promote cellular proliferation and migration in esophageal squamous cell carcinoma cells. FEBS Open Bio 2019; 9:206-225. [PMID: 30761248 PMCID: PMC6356177 DOI: 10.1002/2211-5463.12570] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/19/2018] [Accepted: 10/23/2018] [Indexed: 12/27/2022] Open
Abstract
Some members of the transient receptor potential vanilloid (TRPV) subfamily of cation channels are thermosensitive. Earlier studies have revealed the distribution and functions of these thermo‐TRPVs (TRPV1–4) in various organs, but their expression and function in the human esophagus are not fully understood. Here, we probed for the expression of the thermo‐TRPVs in one nontumor human esophageal squamous cell line and two esophageal squamous cell carcinoma (ESCC) cell lines. TRPV1, TRPV2, and TRPV4 proteins were found to be upregulated in ESCC cells, while TRPV3 was not detectable in any of these cell lines. Subsequently, channel function was evaluated via monitoring of Ca2+ transients by Ca2+ imaging and nonselective cation channel currents were recorded by whole‐cell patch clamp. We found that TRPV4 was activated by heat at 28 °C–35 °C, whereas TRPV1 and TRPV2 were activated by higher, noxious temperatures (44 °C and 53 °C, respectively). Furthermore, TRPV1 was activated by capsaicin (EC50 = 20.32 μm), and this effect was antagonized by AMG9810; TRPV2 was activated by a newly developed cannabinoid compound, O1821, and inhibited by tranilast. In addition, TRPV4 was activated by hypotonic solutions (220 m Osm), and this effect was abolished by ruthenium red. The effects of TRPV1 and TRPV4 on ESCC were also explored. Our data, for the first time, showed that the overactivation of TRPV1 and TRPV4 promoted the proliferation and/or migration of ESCC cells. In summary, TRPV1, TRPV2, and TRPV4 were functionally expressed in human esophageal squamous cells, and thermo‐TRPVs might play an important role in the development of ESCC.
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Affiliation(s)
- Rongqi Huang
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China.,University of Chinese Academy of Sciences Beijing China
| | - Fei Wang
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Yuchen Yang
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Wenbo Ma
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Zuoxian Lin
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Na Cheng
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China.,Department of Anatomy and Neurobiology Xiangya School of Medicine Central South University Changsha China
| | - Yan Long
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Sihao Deng
- Department of Anatomy and Neurobiology Xiangya School of Medicine Central South University Changsha China
| | - Zhiyuan Li
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China.,University of Chinese Academy of Sciences Beijing China.,Department of Anatomy and Neurobiology Xiangya School of Medicine Central South University Changsha China.,GZMU-GIBH Joint School of Life Sciences Guangzhou Medical University China
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Gao K, Ding D, Sun H, Roth J, Salvi R. Kanamycin Damages Early Postnatal, but Not Adult Spiral Ganglion Neurons. Neurotox Res 2017; 32:603-613. [PMID: 28656549 PMCID: PMC5711550 DOI: 10.1007/s12640-017-9773-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/31/2017] [Accepted: 06/13/2017] [Indexed: 01/13/2023]
Abstract
Although aminoglycoside antibiotics such as kanamycin are widely used clinically to treat life-threatening bacterial infections, ototoxicity remains a significant dose-limiting side effect. The prevailing view is that the hair cells are the primary ototoxic target of aminoglycosides and that spiral ganglion neurons begin to degenerate weeks or months after the hair cells have died due to lack of neurotrophic support. To test the early developmental aspects of this issue, we compared kanamycin-induced hair cell and spiral ganglion pathology in rat postnatal day 3 cochlear organotypic cultures with adult whole cochlear explants. In both adult and postnatal day 3 cultures, hair cell damage began at the base of the cochleae and progressed toward the apex in a dose-dependent manner. In postnatal day 3 cultures, spiral ganglion neurons were rapidly destroyed by kanamycin prior to hair cell loss. In contrast, adult spiral ganglion neurons were resistant to kanamycin damage even at the highest concentration, consistent with in vivo models of delayed SGN degeneration. In postnatal day 3 cultures, kanamycin preferentially damaged type I spiral ganglion neurons, whereas type II neurons were resistant. Spiral ganglion degeneration of postnatal day 3 neurons was associated with upregulation of the superoxide radical and caspase-3-mediated cell death. These results show for the first time that kanamycin is toxic to postnatal day 3 spiral ganglion neurons, but not adult neurons.
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Affiliation(s)
- Kelei Gao
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Hong Sun
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Jerome Roth
- Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan
| | - Richard Salvi
- Department of Otolaryngology Head and Neck Surgery, Xiang Ya Hospital, Central South University, Changsha, Hunan, 410013, China.
- Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan.
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10
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Zhao Y, Wang Z, Lao W, Kuang P, Jiang N, Yin T, Lin W, Zhu H, Ji Y. Anticonvulsant effect of gentamicin on the seizures induced by kainic acid. Neurol Res 2017; 40:45-52. [DOI: 10.1080/01616412.2017.1390932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Yuxiao Zhao
- School of Life Science, Shanghai University, Shanghai, China
| | - Ziyi Wang
- School of Life Science, Shanghai University, Shanghai, China
| | - Wenwen Lao
- School of Life Science, Shanghai University, Shanghai, China
| | - Ping Kuang
- School of Life Science, Shanghai University, Shanghai, China
| | - Nan Jiang
- School of Life Science, Shanghai University, Shanghai, China
| | - Tao Yin
- School of Life Science, Shanghai University, Shanghai, China
| | - Weide Lin
- School of Life Science, Shanghai University, Shanghai, China
| | - Hongyan Zhu
- School of Life Science, Shanghai University, Shanghai, China
| | - Yonghua Ji
- School of Life Science, Shanghai University, Shanghai, China
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Goralczyk A, van Vijven M, Koch M, Badowski C, Yassin MS, Toh SA, Shabbir A, Franco-Obregón A, Raghunath M. TRP channels in brown and white adipogenesis from human progenitors: new therapeutic targets and the caveats associated with the common antibiotic, streptomycin. FASEB J 2017; 31:3251-3266. [PMID: 28416581 DOI: 10.1096/fj.201601081rr] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 03/27/2017] [Indexed: 01/14/2023]
Abstract
Transient receptor potential (TRP) channels are polymodal cell sensors responding to diverse stimuli and widely implicated in the developmental programs of numerous tissues. The evidence for an involvement of TRP family members in adipogenesis, however, is scant. We present the first comprehensive expression profile of all known 27 human TRP genes in mesenchymal progenitors cells during white or brown adipogenesis. Using positive trilineage differentiation as an exclusion criterion, TRP polycystic (P)3, and TPR melastatin (M)8 were found to be uniquely adipospecific. Knockdown of TRPP3 repressed the expression of the brown fat signature genes uncoupling protein (UCP)-1 and peroxisome proliferator-activated receptor γ coactivator (PGC)-1α as well as attenuated forskolin-stimulated uncoupled respiration. However, indices of generalized adipogenesis, such as lipid droplet morphology and fatty acid binding protein (FAPB)-4 expression, were not affected, indicating a principal mitochondrial role of TRPP3. Conversely, activating TRPM8 with menthol up-regulated UCP-1 expression and augmented uncoupled respiration predominantly in white adipocytes (browning), whereas streptomycin antagonized TRPM8-mediated calcium entry, downregulated UCP-1 expression, and mitigated uncoupled respiration; menthol was less capable of augmenting uncoupled respiration (thermogenesis) in brown adipocytes. TRPP3 and TRPM8 hence appear to be involved in the priming of mitochondria to perform uncoupled respiration downstream of adenylate cyclase. Our results also underscore the developmental caveats of using antibiotics in adipogenic studies.-Goralczyk, A., van Vijven, M., Koch, M., Badowski, C., Yassin, M. S., Toh, S.-A., Shabbir, A., Franco-Obregón, A., Raghunath, M. TRP channels in brown and white adipogenesis from human progenitors: new therapeutic targets and the caveats associated with the common antibiotic, streptomycin.
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Affiliation(s)
- Anna Goralczyk
- Department of Biomedical Engineering, National University of Singapore, Singapore.,Life Science Institute, National University of Singapore, Singapore
| | - Marc van Vijven
- Life Science Institute, National University of Singapore, Singapore.,Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Mathilde Koch
- Life Science Institute, National University of Singapore, Singapore.,Department of Biology, Ecole Polytechnique, Palaiseau, France
| | - Cedric Badowski
- Institute of Medical Biology, Agency for Science, Technology, and Research (A*STAR), Singapore
| | - M Shabeer Yassin
- Department of Medicine, National University of Singapore, Singapore
| | - Sue-Anne Toh
- Department of Medicine, National University of Singapore, Singapore.,Department of Medicine, National University Health System, Singapore.,Duke-NUS Graduate Medical School, Singapore.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Asim Shabbir
- Department of Surgery, National University Hospital, Singapore; and
| | - Alfredo Franco-Obregón
- Department of Surgery, National University Hospital, Singapore; and .,BioIonic Currents Electromagnetic Pulsing Systems Laboratory, Department of Surgery, National University of Singapore, Singapore
| | - Michael Raghunath
- Department of Biomedical Engineering, National University of Singapore, Singapore .,Life Science Institute, National University of Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Center for Cell Biology and Tissue Engineering, Competence Center for Tissue Engineering (TEDD), Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Wädenswil, Switzerland
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12
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Mercado F, Almanza A, Simón-Arceo K, López O, Vega R, Coffeen U, Contreras B, Soto E, Pellicer F. Inhibition of peripheral nociceptors by aminoglycosides produces analgesia in inflammatory pain models in the rat. Inflammation 2015; 38:649-57. [PMID: 25028102 DOI: 10.1007/s10753-014-9972-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Aminoglycosides (AGs) modulate nociceptors and ionic channels expressed in sensory neurons. The AG applied in situ could be useful to alleviate hyperalgesia in animal models of inflammatory pain. We tested streptomycin (ST) and neomycin (NEO) as analgesic agents applied in situ in rat paw inflammation caused by formalin or carrageenan administration. The action of ST and NEO on the action potential discharge produced by acidic stimuli in isolated dorsal root ganglion neurons was also studied in current-clamp recordings. In the formalin test, ST and NEO significantly reduced the nociceptive behaviour. ST reduced the N-(4-methyl-2-quinazolinyl)-guanidine (GMQ)-induced nociceptive behaviour, and NEO diminished the hyperalgesia to thermonociception and mechanonociception produced by CAR. In the current-clamp experiments, ST and NEO reduced the generation of action potentials when an acidic solution was applied. We conclude that ST and NEO produce analgesia to inflammatory pain, an effect that is due in part to the inhibition of ASIC activation in sensory neurons.
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Affiliation(s)
- Francisco Mercado
- Laboratorio de Fisiología Celular, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México, D.F., México
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13
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Osmakov DI, Andreev YA, Kozlov SA. Acid-sensing ion channels and their modulators. BIOCHEMISTRY (MOSCOW) 2015; 79:1528-45. [PMID: 25749163 DOI: 10.1134/s0006297914130069] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
According to a modern look acid-sensing ion channels (ASICs) are one of the most important receptors that perceive pH change in the body. ASICs represent proton-gated Na+-selective channels, which are expressed in neurons of the central and peripheral nervous system. These channels are attracting attention of researchers around the world, as they are involved in various physiological processes in the body. Drop of pH may occur in tissues in norm (e.g. the accumulation of lactic acid, the release of protons upon ATP hydrolysis) and pathology (inflammation, ischemic stroke, tissue damage and seizure). These processes are accompanied by unpleasant pain sensations, which may be short-lived or can lead to chronic inflammatory diseases. Modulators of ASIC channels activity are potential candidates for new effective analgesic and neuroprotection drugs. This review summarizes available information about structure, function, and physiological role of ASIC channels. In addition a description of all known ligands of these channels and their practical relevance is provided.
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Affiliation(s)
- D I Osmakov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
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14
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Martinac B. The ion channels to cytoskeleton connection as potential mechanism of mechanosensitivity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:682-91. [PMID: 23886913 DOI: 10.1016/j.bbamem.2013.07.015] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 07/05/2013] [Accepted: 07/15/2013] [Indexed: 01/07/2023]
Abstract
As biological force-sensing systems mechanosensitive (MS) ion channels present the best example of coupling molecular dynamics of membrane proteins to the mechanics of the surrounding cell membrane. In animal cells MS channels have over the past two decades been very much in focus of mechanotransduction research. In recent years this helped to raise awareness of basic and medical researchers about the role that abnormal MS channels may play in the pathophysiology of diseases, such as cardiac hypertrophy, atrial fibrillation, muscular dystrophy or polycystic kidney disease. To date a large number of MS channels from organisms of diverse phylogenetic origins have been identified at the molecular level; however, the structure of only few of them has been determined. Although their function has extensively been studied in a great variety of cells and tissues by different experimental approaches it is, with exception of bacterial MS channels, very little known about how these channels sense mechanical force and which cellular components may contribute to their function. By focusing on MS channels found in animal cells this article discusses the ways in which the connections between cytoskeleton and ion channels may contribute to mechanosensory transduction in these cells. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Boris Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, NSW 2052, Australia.
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15
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Urbanek DA, Proschak E, Tanrikulu Y, Becker S, Karas M, Schneider G. Scaffold-hopping from aminoglycosides to small synthetic inhibitors of bacterial protein biosynthesis using a pseudoreceptor model. MEDCHEMCOMM 2011. [DOI: 10.1039/c0md00207k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Bongartz EV, Rettinger J, Hausmann R. Aminoglycoside block of P2X2 receptors heterologously expressed in Xenopus laevis oocytes. Purinergic Signal 2010; 6:393-403. [PMID: 21437010 DOI: 10.1007/s11302-010-9204-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 11/01/2010] [Indexed: 12/01/2022] Open
Abstract
Aminoglycosides are polycationic antibiotics that have been shown to block a variety of cation channels. The inhibitory effect of externally applied aminoglycosides on P2X2 receptor currents was examined after heterologous expression in Xenopus laevis oocytes using the two-electrode voltage-clamp technique. All of the aminoglycosides tested inhibited the ATP-evoked responses with potencies ranging from 71 μM to 2 mM (IC(50) values). The ranked order of potency was streptomycin > gentamicin > neomycin > paromomycin > kanamycin. The inhibition of P2X receptor currents was independent of the ATP concentration used for the activation, which is compatible with a noncompetitive mechanism. The inhibition was voltage-dependent and was reduced at more positive membrane potentials. To examine whether the current block was dependent on the receptor conformation, the aminoglycoside effect on a non-desensitizing P2X2-X1 receptor chimera was analyzed. The results from these measurements suggest that inhibition is caused by an open pore block that locks the P2X receptor chimera in an open nonconducting state from which the agonist dissociation is slow. We also demonstrate that the P2X2-X1 chimera can serve as a tool to directly test whether an antagonist acts competitively or not.
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17
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Padilla IMG, Burgos L. Aminoglycoside antibiotics: structure, functions and effects on in vitro plant culture and genetic transformation protocols. PLANT CELL REPORTS 2010; 29:1203-13. [PMID: 20644935 DOI: 10.1007/s00299-010-0900-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/06/2010] [Accepted: 07/06/2010] [Indexed: 05/12/2023]
Abstract
Plant transformation protocols generally involve the use of selectable marker genes for the screening of transgenic material. The bacterial gene nptII, coding for a neomycin phosphotransferase, and the hpt gene, coding for a hygromycin phosphotransferase, are frequently used. These enzymes detoxify aminoglycoside antibiotics by phosphorylation, thereby permitting cell growth in the presence of antibiotics. Nevertheless, the screening for transgenic regenerated shoots is often partial and difficult due to regeneration of escapes and chimeras. These difficulties can be caused, in part, by an incorrect assumption about the mode of action of antibiotics in bacterial and eukaryotic cells and in in vitro tissue culture. The information contained in this review could be useful to establish better selection strategies by taking into account factors such as explant complexity, transformation and selection protocols that allow better accessibility to cells of Agrobacterium and antibiotics, and faster regeneration methods that avoid collateral effects of antibiotics on recovered, putative transgenic shoots.
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Affiliation(s)
- I M G Padilla
- Grupo de Biotecnología de Frutales, Departamento de Mejora, CEBAS-CSIC, Campus Universitario de Espinardo, Apartado de correos 164, 30100, Murcia, Spain.
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18
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Jara-Oseguera A, Simon SA, Rosenbaum T. TRPV1: on the road to pain relief. Curr Mol Pharmacol 2010; 1:255-69. [PMID: 20021438 DOI: 10.2174/1874467210801030255] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Historically, drug research targeted to pain treatment has focused on trying to prevent the propagation of action potentials in the periphery from reaching the brain rather than pinpointing the molecular basis underlying the initial detection of the nociceptive stimulus: the receptor itself. This has now changed, given that many receptors of nociceptive stimuli have been identified and/or cloned. Transient Receptor Potential (TRP) channels have been implicated in several physiological processes such as mechanical, chemical and thermal stimuli detection. Ten years after the cloning of TRPV1, compelling data has been gathered on the role of this channel in inflammatory and neuropathic states. TRPV1 activation in nociceptive neurons, where it is normally expressed, triggers the release of neuropeptides and transmitters resulting in the generation of action potentials that will be sent to higher CNS areas where they will often be perceived as pain. Its activation also will evoke the peripheral release of pro-inflammatory compounds that may sensitize other neurons to physical, thermal or chemical stimuli. For these reasons as well as because its continuous activation causes analgesia, TRPV1 has become a viable drug target for clinical use in the management of pain. This review will provide a general picture of the physiological and pathophysiological roles of the TRPV1 channel and of its structural, pharmacological and biophysical properties. Finally, it will provide the reader with an overall view of the status of the discovery of potential therapeutic agents for the management of chronic and neuropathic pain.
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Affiliation(s)
- Andrés Jara-Oseguera
- Departamento de Biofísica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
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Garza A, López-Ramírez O, Vega R, Soto E. The aminoglycosides modulate the acid-sensing ionic channel currents in dorsal root ganglion neurons from the rat. J Pharmacol Exp Ther 2009; 332:489-99. [PMID: 19864615 DOI: 10.1124/jpet.109.152884] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Acid-sensing ionic channels (ASICs) have been shown to have a significant role in a growing number of physiological and pathological processes, such as nociception, synaptic transmission and plasticity, mechanosensation, and acidosis-induced neuronal injury. The discovery of pharmacological agents targeting ASICs has significant therapeutic potential and use as a research tool. In our work, we studied the action of transient perfusion (5-15 s) of aminoglycosides (AGs) (streptomycin and neomycin) on the proton-gated ionic currents in dorsal root ganglion (DRG) neurons of the rat and in human embryonic kidney (HEK)-293 cells. In DRG neurons, streptomycin and neomycin (30 microM) produced a significant, concentration-dependent, and reversible reduction in the amplitude of the proton-gated current, and a slowing of the desensitization rate of the ASIC current. Gentamycin (30 microM) also showed a significant reversible action on the ASIC currents. The curves of the pH effect for streptomycin and neomycin indicated that their effect was not significantly affected by pH. In HEK-293 cells, streptomycin (30 microM) produced a significant reduction in the amplitude of the proton-gated current. Neomycin and gentamycin had no significant action. Reduction of extracellular Ca(2+) concentration produced a significant increase in the action of streptomycin and neomycin on the desensitization time course of ASIC currents. These results indicate that ASICs are molecular targets for AGs, which may contribute to the understanding of their actions on excitable cells. Moreover, AGs may constitute a source to develop novel molecules with a greater affinity, specificity, and selectivity for the different ASIC subunits.
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Affiliation(s)
- Aníbal Garza
- Instituto de Fisiología, Universidad Autónoma de Puebla, Puebla, Pue. CP 72570, México
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van den Wijngaard RM, Welting O, Bulmer DC, Wouters MM, Lee K, de Jonge WJ, Boeckxstaens GE. Possible role for TRPV1 in neomycin-induced inhibition of visceral hypersensitivity in rat. Neurogastroenterol Motil 2009; 21:863-e60. [PMID: 19298229 DOI: 10.1111/j.1365-2982.2009.01287.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Transient receptor ion channel 1 (TRPV1) is a nociceptor involved in visceral hypersensitivity. Aminoglycosides like neomycin are not only potent antibiotics but in vitro data suggest that neomycin also acts as a TRPV1-antagonist and alleviates somatic pain responses. To what extent neomycin reduces visceral hypersensitivity remains unknown. Therefore, we aimed to investigate whether neomycin can inhibit in vivo TRPV1-dependent hypersensitivity responses in two rat models of visceral pain. In the first model rats were pretreated with intraperitoneal (i.p.) capsazepine, the selective TRPV1 antagonist SB-705498, neomycin or vehicle alone and 30 min later instilled with intracolonic TRPV1-activating capsaicin. Likewise, rats were pretreated with 10 days oral neomycin and then subjected to intracolonic capsaicin. The visceromotor response (VMR) to distension was measured before and after capsaicin application. In addition, the VMR to distension was measured in adult maternal separated rats before and after acute stress. Before the 2nd distension protocol these rats were treated with i.p. neomycin, amoxycillin or vehicle alone. Our results showed that capsaicin administration induced an enhanced VMR to distension that was prevented by i.p. capsazepine, SB-705498 and neomycin. Oral neomycin treatment changed bacterial faecal content but could not inhibit capsaicin induced visceral hypersensitivity. In maternal separated rats acute stress induced an enhanced response to distension that was reversed by i.p. neomycin, but not amoxycillin. These data indicate that (i.p.) neomycin can inhibit visceral hypersensitivity to distension in a nonbactericidal manner and suggest that TRPV1-modulation may be involved.
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Korepanova A, Pereda-Lopez A, Solomon LR, Walter KA, Lake MR, Bianchi BR, McDonald HA, Neelands TR, Shen J, Matayoshi ED, Moreland RB, Chiu ML. Expression and purification of human TRPV1 in baculovirus-infected insect cells for structural studies. Protein Expr Purif 2008; 65:38-50. [PMID: 19121396 DOI: 10.1016/j.pep.2008.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 11/11/2008] [Accepted: 12/03/2008] [Indexed: 10/21/2022]
Abstract
TRPV1 is a ligand-gated cation channel that is involved in acute thermal nociception and neurogenic inflammation. By using the GP67 signal peptide, high levels of full-length human TRPV1 was expressed in High Five insect cells using the baculovirus expression system. The functional activity of the expressed TRPV1 was confirmed by whole-cell ligand-gated ion flux recordings in the presence of capsaicin and low pH and via specific ligand binding to the isolated cellular membranes. Efficient solubilization and purification protocols have resulted in milligram amounts of detergent-solubilized channel at 80-90% purity after Ni2+ IMAC chromatography and size exclusion chromatography. Western blot analysis of amino and carboxyl terminal domains and MS of tryptic digestions of purified protein confirmed the presence of the full-length human TRPV1. Specific ligand binding experiments confirmed the protein integrity of the purified human TRPV1.
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Affiliation(s)
- Alla Korepanova
- Department of Structural Biology, R46Y, Abbott Laboratories, Bldg. AP10-LL8, 100 Abbott Park Rd., Abbott Park, IL 60064-6098, USA.
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Scholz-Starke J, Carpaneto A, Gambale F. On the interaction of neomycin with the slow vacuolar channel of Arabidopsis thaliana. ACTA ACUST UNITED AC 2006; 127:329-40. [PMID: 16505151 PMCID: PMC2151498 DOI: 10.1085/jgp.200509402] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
This study investigates the interaction of the aminoglycoside antibiotic neomycin with the slow vacuolar (SV) channel in vacuoles from Arabidopsis thaliana mesophyll cells. Patch-clamp experiments in the excised patch configuration revealed a complex pattern of neomycin effects on the channel: applied at concentrations in the submicromolar to millimolar range neomycin (a) blocked macroscopic SV currents in a voltage- and concentration-dependent manner, (b) slowed down activation and deactivation kinetics of the channel, and most interestingly, (c) at concentrations above 10 μM, neomycin shifted the SV activation threshold towards negative membrane potentials, causing a two-phasic activation at high concentrations. Single channel experiments showed that neomycin causes these macroscopic effects by combining a decrease of the single channel conductance with a concomitant increase of the channel's open probability. Our results clearly demonstrate that the SV channel can be activated at physiologically relevant tonoplast potentials in the presence of an organic effector molecule. We therefore propose the existence of a cellular equivalent regulating the activity of the SV channel in vivo.
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Dai C, Mangiardi D, Cotanche D, Steyger P. Uptake of fluorescent gentamicin by vertebrate sensory cells in vivo. Hear Res 2006; 213:64-78. [PMID: 16466873 PMCID: PMC2424187 DOI: 10.1016/j.heares.2005.11.011] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Revised: 10/26/2005] [Accepted: 11/25/2005] [Indexed: 11/16/2022]
Abstract
Aminoglycoside uptake in the inner ear remains poorly understood. We subcutaneously injected a fluorescently-conjugated aminoglycoside, gentamicin-Texas Red (GTTR), to investigate the in vivo uptake of GTTR in the inner ear of several vertebrates, and in various murine sensory cells using confocal microscopy. In bullfrogs, GTTR uptake was prominent in mature hair cells, but not in immature hair cells. Avian hair cells accrued GTTR more rapidly at the base of the basilar papilla. GTTR was associated with the hair bundle; and, in guinea pigs and mice, somatic GTTR fluorescence was initially diffuse before punctate (endosomal) fluorescence could be observed. A baso-apical gradient of intracellular GTTR uptake in guinea pig cochleae could only be detected at early time points (<3h). In 21-28 day mice, cochlear GTTR uptake was greatly reduced compared to guinea pigs, 6-day-old mice, or mice treated with ethacrynic acid. In mice, GTTR was also rapidly taken up, and retained, in the kidney, dorsal root and trigeminal ganglia. In linguinal and vibrissal tissues rapid GTTR uptake cleared over a period of several days. The preferential uptake of GTTR by mature saccular, and proximal hair cells resembles the pattern of aminoglycoside-induced hair cell death in bullfrogs and chicks. Differences in the degree of GTTR uptake in hair cells of different species suggests variation in serum levels, clearance rates from serum, and/or the developmental and functional integrity of the blood-labyrinth barrier. GTTR uptake by hair cells in vivo suggests that GTTR has potential to elucidate aminoglycoside transport mechanisms into the inner ear, and as a bio-tracer for in vivo pharmacokinetic studies.
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Affiliation(s)
- C.F. Dai
- Oregon Hearing Research Center, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, United States
- Department of Otolaryngology, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai 200031, PR China
| | - D. Mangiardi
- Department of Otolaryngology, Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States
- Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215, United States
| | - D.A. Cotanche
- Department of Otolaryngology, Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States
| | - P.S. Steyger
- Oregon Hearing Research Center, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, United States
- Corresponding author. Tel.: +1 503 494 1062; fax: +1 503 494 5656. E-mail address: (P.S. Steyger)
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Johansen ME, Reilly CA, Yost GS. TRPV1 antagonists elevate cell surface populations of receptor protein and exacerbate TRPV1-mediated toxicities in human lung epithelial cells. Toxicol Sci 2005; 89:278-86. [PMID: 16120755 PMCID: PMC2291391 DOI: 10.1093/toxsci/kfi292] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
TRPV1 mediates cell death and pro-inflammatory cytokine production in lung epithelial cells exposed to prototypical receptor agonists. This study shows that NHBE, BEAS-2B and TRPV1 over-expressing BEAS-2B cells pre-treated with various TRPV1 antagonists become sensitized to the prototypical TRPV1 agonist, nonivamide, via a mechanism that involves translocation of existing receptor from the endoplasmic reticulum to the plasma membrane. As such, typical cellular responses to agonist treatment, as measured by calcium flux, inflammatory cytokine gene induction, and cytotoxicity were exacerbated. These data were in contrast to the results obtained when TRPV1 antagonists were co-administered with nonivamide; conditions which inhibited TRPV1-mediated effects. The antagonists LJO-328, SC0030, and capsazepine increased the cytotoxicity of nonivamide by approximately 20-fold and agonist-induced calcium flux by approximately 6-fold. Inflammatory-cytokine gene induction by nonivamide was also increased significantly by pre-treatment with the antagonists. The enhanced responses were inhibited by the co-administration of antagonists with nonivamide, confirming that increases in sensitivity were attributable to increased TRPV1-associated activity. Sensitization was attenuated by brefeldin A (a golgi transport inhibitor), but not cycloheximide (a protein synthesis inhibitor), or actinomycin D (a transcription inhibitor). Sensitized cells exhibited increased calcium flux from extracellular calcium sources, while unsensitized cells exhibited calcium flux originating primarily from intracellular stores. These results demonstrate the presence of a novel mechanism for regulating the sub-cellular distribution of TRPV1 and subsequent control of cellular sensitivity to TRPV1 agonists.
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Affiliation(s)
| | - Christopher A. Reilly
- To whom correspondence should be addressed at University of Utah, Department of Pharmacology and Toxicology, 30 S. 2000 E., Room 201 Skaggs Hall, Salt Lake City, UT 84112. Fax: (801) 585-3945. E-mail:
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