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Song T, Hui W, Huang M, Guo Y, Yu M, Yang X, Liu Y, Chen X. Dynamic Changes in Ion Channels during Myocardial Infarction and Therapeutic Challenges. Int J Mol Sci 2024; 25:6467. [PMID: 38928173 PMCID: PMC11203447 DOI: 10.3390/ijms25126467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 06/02/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
In different areas of the heart, action potential waveforms differ due to differences in the expressions of sodium, calcium, and potassium channels. One of the characteristics of myocardial infarction (MI) is an imbalance in oxygen supply and demand, leading to ion imbalance. After MI, the regulation and expression levels of K+, Ca2+, and Na+ ion channels in cardiomyocytes are altered, which affects the regularity of cardiac rhythm and leads to myocardial injury. Myocardial fibroblasts are the main effector cells in the process of MI repair. The ion channels of myocardial fibroblasts play an important role in the process of MI. At the same time, a large number of ion channels are expressed in immune cells, which play an important role by regulating the in- and outflow of ions to complete intracellular signal transduction. Ion channels are widely distributed in a variety of cells and are attractive targets for drug development. This article reviews the changes in different ion channels after MI and the therapeutic drugs for these channels. We analyze the complex molecular mechanisms behind myocardial ion channel regulation and the challenges in ion channel drug therapy.
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Affiliation(s)
- Tongtong Song
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
- Department of Anatomy, College of Basic Medical Sciences, Jilin University, Changchun 130012, China
| | - Wenting Hui
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Min Huang
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Yan Guo
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Meiyi Yu
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Xiaoyu Yang
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Yanqing Liu
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
| | - Xia Chen
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China; (T.S.); (W.H.); (M.H.); (Y.G.); (M.Y.); (X.Y.); (Y.L.)
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Germoush MO, Fouda M, Aly H, Saber I, Alrashdi BM, Massoud D, Alzwain S, Altyar AE, Abdel-Daim MM, Sarhan M. Proteomic analysis of the venom of Conus flavidus from Red Sea reveals potential pharmacological applications. J Genet Eng Biotechnol 2024; 22:100375. [PMID: 38797555 PMCID: PMC11066669 DOI: 10.1016/j.jgeb.2024.100375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/15/2024] [Accepted: 03/28/2024] [Indexed: 05/29/2024]
Abstract
BACKGROUND Venomous marine cone snails produce unique neurotoxins called conopeptides or conotoxins, which are valuable for research and drug discovery. Characterizing Conus venom is important, especially for poorly studied species, as these tiny and steady molecules have considerable potential as research tools for detecting new pharmacological applications. In this study, a worm-hunting cone snail, Conus flavidus inhabiting the Red Sea coast were collected, dissected and the venom gland extraction was subjected to proteomic analysis to define the venom composition, and confirm the functional structure of conopeptides. RESULTS Analysis of C. flavidus venom identified 117 peptide fragments and assorted them to conotoxin precursors and non-conotoxin proteins. In this procedure, 65 conotoxin precursors were classified and identified to 16 conotoxin precursors and hormone superfamilies. In the venom of C. flavidus, the four conotoxin superfamilies T, A, O2, and M were the most abundant peptides, accounting for 75.8% of the total conotoxin diversity. Additionally, 19 non-conotoxin proteins were specified in the venom, as well as several potentially biologically active peptides with putative applications. CONCLUSION Our research displayed that the structure of the C. flavidus-derived proteome is similar to other Conus species and includes toxins, ionic channel inhibitors, insulin-like peptides, and hyaluronidase. This study provides a foundation for discovering new conopeptides from C. flavidus venom for pharmaceutical use.
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Affiliation(s)
- Mousa O Germoush
- Biology Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia.
| | - Maged Fouda
- Biology Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia
| | - Hamdy Aly
- Zoology Department, Faculty of Science, Al-Azhar University, Assiut Branch 71524, Assuit, Egypt
| | - Islam Saber
- Zoology Department, Faculty of Science, Al-Azhar University, Assiut Branch 71524, Assuit, Egypt
| | - Barakat M Alrashdi
- Biology Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia
| | - Diaa Massoud
- Biology Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia
| | - Sarah Alzwain
- Biology Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia
| | - Ahmed E Altyar
- Department of Pharmacy Practice, Faculty of Pharmacy, King Abdulaziz University, P.O. Box 80260, Jeddah 21589, Saudi Arabia; Pharmacy Program, Batterjee Medical College, P.O. Box 6231, Jeddah 21442, Saudi Arabia
| | - Mohamed M Abdel-Daim
- Department of Pharmaceutical Sciences, Pharmacy Program, Batterjee Medical College, P.O. Box 6231, Jeddah 21442, Saudi Arabia; Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Moustafa Sarhan
- Zoology Department, Faculty of Science, Al-Azhar University, Assiut Branch 71524, Assuit, Egypt; Department of Biomedical Sciences, College of Clinical Pharmacy, King Faisal University, 31982, Saudi Arabia
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Kalatharan V, Al-Karagholi MAM. Targeting Peripheral N-Methyl-D-Aspartate Receptor (NMDAR): A Novel Strategy for the Treatment of Migraine. J Clin Med 2023; 12:jcm12062156. [PMID: 36983158 PMCID: PMC10055974 DOI: 10.3390/jcm12062156] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/23/2023] [Accepted: 03/02/2023] [Indexed: 03/12/2023] Open
Abstract
Backgrounds: Several acute and preventive medications were developed for the treatment of migraine. Yet, a significant proportion of patients reports an inadequate response and a lack of tolerability, emphasizing the need for new options. Glutamate is the most important excitatory neurotransmitter in the brain, and glutamate receptors including N-Methyl-D-Aspartate Receptor (NMDAR) are expressed at several levels of the trigeminovascular system, which is the anatomical and physiological substrate of migraine pain. Objective: To review preclinical and clinical studies investigating the role of the NMDAR in migraine pathophysiology. Methods: No protocol was registered for this study. References for the present review were identified from a narrative search of the PubMed database. Search terms such as glutamate, migraine, N-Methyl-D-Aspartate Receptor, and NMDAR were used. No restrictions were made in terms of the language and date of publication. Results: In animal models, administration of monosodium glutamate (MSG) activated and sensitized trigeminovascular neurons. In healthy human participants, consumption of MSG caused headaches, craniofacial sensitivity, and nausea. In in vivo models and through immunolabeling, NMDAR subunits NR1, NR2A, and NR2B were expressed in trigeminal ganglion neurons. In humans, NMDAR antagonists such as ketamine and memantine caused a significant reduction in pain intensity and monthly headache frequency. Conclusions: Accumulative evidence indicates that NMDAR is a promising new target for the treatment of migraine. Selective NMDAR antagonists without central effects are needed to investigate their therapeutic benefit in the treatment of migraine.
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Tsai SY, Huang CC, Chen PH, Tripathi A, Wang YR, Wang YL, Chen JC. Rapid Drug-Screening Platform Using Field-Effect Transistor-Based Biosensors: A Study of Extracellular Drug Effects on Transmembrane Potentials. Anal Chem 2021; 94:2679-2685. [PMID: 34919373 DOI: 10.1021/acs.analchem.1c03402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ion channel-modulating drugs play an important role in treating cardiovascular diseases. Facing the demands for continuous monitoring of drug effectiveness, the conventional techniques have become limited when investigating a long-term cellular physiology. To address the challenge, we propose a drug-screening platform using the stretch-out electrical double layer (EDL)-gated field-effect transistor-based biosensors (BioFETs). In this work, BioFETs were utilized to amplify electrophysiological signals from the mammalian cardiomyocytes (H9c2). The stretch-out configuration avoided a chemical corrosion on FETs and prolonged the lifetime of a BioFET system. A physical model is presented to elucidate the signal response to a drug effect on a cell. Fibronectin and gelatin were coated on sensors and served as the adhesive layers where H9c2 cells attached. BioFETs demonstrated an ability to qualitatively distinguish a depolarization and a polarization of the cytomembranes. The signal responses to the changes of transmembrane potentials were monitored in real-time, and they were highly correlated. The effects of nifedipine and calcium ions on cellular electrophysiology were examined and discussed. Due to the capability of a rapid detection, a prolonged lifetime, and an excellent sensitivity to an electrical change, a stretch-out EDL-gated BioFET can be a drug-screening platform for ion channel modulators.
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Affiliation(s)
- Shu-Yi Tsai
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Chih-Cheng Huang
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Po-Hsuan Chen
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Adarsh Tripathi
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Yu-Rong Wang
- Institute of Biomedical Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan, Republic of China
| | - Yu-Lin Wang
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China.,Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
| | - Jung-Chih Chen
- Institute of Biomedical Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan, Republic of China.,Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan, Republic of China.,Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan, Republic of China.,Catholic Mercy Hospital, Catholic Mercy Medical Foundation, Hsinchu 30342, Taiwan, Republic of China
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Fouda MMA, Abdel-Wahab M, Mohammadien A, Germoush MO, Sarhan M. Proteomic analysis of Red Sea Conus taeniatus venom reveals potential biological applications. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20210023. [PMID: 34712278 PMCID: PMC8525892 DOI: 10.1590/1678-9199-jvatitd-2021-0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/12/2021] [Indexed: 11/26/2022] Open
Abstract
Background: Diverse and unique bioactive neurotoxins known as conopeptides or conotoxins
are produced by venomous marine cone snails. Currently, these small and
stable molecules are of great importance as research tools and platforms for
discovering new drugs and therapeutics. Therefore, the characterization of
Conus venom is of great significance, especially for
poorly studied species. Methods: In this study, we used bioanalytical techniques to determine the venom
profile and emphasize the functional composition of conopeptides in
Conus taeniatus, a neglected worm-hunting cone snail.
Results: The proteomic analysis revealed that 84.0% of the venom proteins were between
500 and 4,000 Da, and 16.0% were > 4,000 Da. In C.
taeniatus venom, 234 peptide fragments were identified and
classified as conotoxin precursors or non-conotoxin proteins. In this
process, 153 conotoxin precursors were identified and matched to 23
conotoxin precursors and hormone superfamilies. Notably, the four conotoxin
superfamilies T (22.87%), O1 (17.65%), M (13.1%) and O2 (9.8%) were the most
abundant peptides in C. taeniatus venom, accounting for
63.40% of the total conotoxin diversity. On the other hand, 48 non-conotoxin
proteins were identified in the venom of C. taeniatus.
Moreover, several possibly biologically active peptide matches were
identified, and putative applications of the peptides were assigned. Conclusion: Our study showed that the composition of the C.
taeniatus-derived proteome is comparable to that of other
Conus species and contains an effective mix of toxins,
ionic channel inhibitors and antimicrobials. Additionally, it provides a
guidepost for identifying novel conopeptides from the venom of C.
taeniatus and discovering conopeptides of potential
pharmaceutical importance.
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Affiliation(s)
- Maged M A Fouda
- Department of Biology, College of Science, Jouf University, Saudi Arabia.,Zoology Department, Faculty of Science, Al-Azhar University, Assiut, Egypt
| | | | - Amal Mohammadien
- Department of Biology, College of Science, Taeif University, Saudi Arabia.,Zoology Department, Faculty of Science, Zagazig University, Zagazig, Egypt
| | - Mousa O Germoush
- Department of Biology, College of Science, Jouf University, Saudi Arabia
| | - Moustafa Sarhan
- Zoology Department, Faculty of Science, Al-Azhar University, Assiut, Egypt
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Chappe Y, Michel P, Joushomme A, Barbeau S, Pierredon S, Baron L, Garenne A, Poulletier De Gannes F, Hurtier A, Mayer S, Lagroye I, Quignard JF, Ducret T, Compan V, Franchet C, Percherancier Y. High-throughput screening of TRPV1 ligands in the light of the Bioluminescence Resonance Energy Transfer technique. Mol Pharmacol 2021; 100:237-257. [PMID: 34127538 DOI: 10.1124/molpharm.121.000271] [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: 03/05/2021] [Accepted: 05/17/2021] [Indexed: 11/22/2022] Open
Abstract
Ion channels are attractive drug targets for many therapeutic applications. However, high-throughput screening (HTS) of drug candidates is difficult and remains very expensive. We thus assessed the suitability of the Bioluminescence Resonance Energy Transfer (BRET) technique as a new HTS method for ion-channel studies by taking advantage of our recently characterized intra- and intermolecular BRET probes targeting the TRPV1 ion channel. These BRET probes monitor conformational changes during TRPV1 gating and subsequent coupling with Calmodulin, two molecular events that are intractable using reference techniques such as automated calcium assay (ACA) and automated patch-clamp (APC). We screened the small-sized Prestwick chemical library, encompassing 1200 compounds with high structural diversity, using either intra- and intermolecular BRET probes or ACA. Secondary screening of the detected hits was done using APC. Multiparametric analysis of our results shed light on the capability of calmodulin inhibitors included in the Prestwick library to inhibit TRPV1 activation by Capsaicin (CAPS). BRET was the lead technique for this identification process. Finally, we present data exemplifying the use of intramolecular BRET probes to study other TRPs and non-TRPs ion channels. Knowing the ease of use of BRET biosensors and the low cost of the BRET technique, these assays may advantageously be included for extending ion-channel drug screening. Significance Statement We screened a chemical library against TRPV1 ion channel using Bioluminescence Resonance Energy Transfer (BRET) molecular probes, and compared the results with the ones obtained using reference techniques such as automated calcium assay and automated patch-clamp. Multiparametric analysis of our results shed light on the capability of Calmodulin antagonists to inhibit chemical activation of TRPV1, and indicates that BRET probes may advantageously be included in ion channel drug screening campaigns.
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Affiliation(s)
- Yann Chappe
- IMS laboratory / CNRS UMR 5218, Bordeaux University, France
| | | | | | - Solène Barbeau
- Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux University, France
| | - Sandra Pierredon
- CNRS UMR 5203 - INSERM U1191, Institut de Genomique Fonctionnelle, France
| | | | - André Garenne
- IMS laboratory / CNRS UMR 5218, Bordeaux University, France
| | | | | | | | | | - Jean-François Quignard
- Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux University, France
| | - Thomas Ducret
- Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux University, France
| | - Vincent Compan
- CNRS UMR 5203 - INSERM U1191, Institut de Genomique Fonctionnelle, France
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Gao S, Liang H, Shou Z, Yao Y, Lv Y, Shang J, Lu W, Jia C, Liu Q, Zhang H, Xiao L. De novo transcriptomic and proteomic analysis and potential toxin screening of Mesobuthus martensii samples from four different provinces. JOURNAL OF ETHNOPHARMACOLOGY 2021; 265:113268. [PMID: 32810618 DOI: 10.1016/j.jep.2020.113268] [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: 02/26/2020] [Revised: 07/04/2020] [Accepted: 08/09/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE As well-known medicinal materials in traditional Chinese medicine, scorpions, commonly called as Quanxie () in Chinese, have been widely used to treat several diseases such as rheumatoid arthritis, apoplexy, epilepsy and chronic pain for more than a thousand years. Not only in the ancient times, the scorpions have also been recorded nowadays in the Pharmacopoeia of the People's Republic of China since 1963. AIM OF STUDY This study aims to explore the differences in composition of the venom of scorpions from different regions by using the method of transcriptomics and proteomics. MATERIALS AND METHODS Whole de novo transcriptomes, proteomics and their bioinformatic analyses were performed on samples of the scorpion Mesobuthus martensii and their venoms from four different provinces with clear geographical boundaries, including Hebei, Henan, Shandong and Shanxi. RESULTS The four captured samples had the same morphology, and the conserved CO-1 sequence matched that of M. martensii. A total of 141,003 of 174,653 transcripts were identified as unigenes, of which we successfully annotated 51,627 (36.61%), 21,970 (15.58%), 7,168 (5.08%), and 45,263 (32.10%) unigenes with the NR, GO, KEGG and SWISSPROT databases, respectively, while a total of 427 proteins were collected from the protein extracted from venoms. Both GO and KEGG annotations exhibited only slight differences among the four samples while the expression level of gene and protein was quite different. A total of 249 toxin-related unigenes were successfully screened, including 41 serine proteases and serine protease inhibitors, 39 potassium channel toxins, 38 phospholipases, 16 host defense peptides, 9 metalloproteases, and 50 other toxins. Although the toxin species were similar among the four samples, the gene expression of each toxin varied considerably, for example, the scorpion from HB province has the most abundant expression quality in sequences c48391_g1, c55239_g1 and c47749_g1 while the lowest expressions of c51178_g1, c62033_g3 and c63754_g2. CONCLUSION The regional differences in the transcriptomes and proteomes of M. martensii are mainly from expression levels e.g. toxins rather than expression species, of which the method can be further extended to evaluate the qualities of traditional Chinese medicines obtained from different regions.
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Affiliation(s)
- Songyu Gao
- Faculty of Naval Medicine, Second Military Medical University (Naval Medical University), Shanghai, 200433, China.
| | - Hongyu Liang
- Faculty of Naval Medicine, Second Military Medical University (Naval Medical University), Shanghai, 200433, China; College of Traditional Chinese Medicine, Jilin Agricultural University, Changchun, 130118, China.
| | - Zhaoyong Shou
- Faculty of Health Service, Second Military Medical University (Naval Medical University), Shanghai, 200433, China.
| | - Yuzhe Yao
- School of Nursing, Second Military Medical University (Naval Medical University), Shanghai, 200433, China.
| | - Yang Lv
- Faculty of Naval Medicine, Second Military Medical University (Naval Medical University), Shanghai, 200433, China.
| | - Jing Shang
- School of Nursing, Second Military Medical University (Naval Medical University), Shanghai, 200433, China.
| | - Wei Lu
- 905th Hospital of PLA Navy, Second Military Medical University (Naval Medical University), Shanghai, 200052, China.
| | - Changliang Jia
- Faculty of Naval Medicine, Second Military Medical University (Naval Medical University), Shanghai, 200433, China.
| | - Qing Liu
- College of Animal Science and Veterinary Medicine, ShanXi Agricultural University, ShanXi, TaiGu, 030801, China.
| | - Haiyan Zhang
- Department of Health Care, Changhai Hospital, Second Military Medical University (Naval Medical University), Shanghai, 200433, China.
| | - Liang Xiao
- Faculty of Naval Medicine, Second Military Medical University (Naval Medical University), Shanghai, 200433, China.
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Li X, Chen W, Zhangsun D, Luo S. Diversity of Conopeptides and Their Precursor Genes of Conus Litteratus. Mar Drugs 2020; 18:md18090464. [PMID: 32937857 PMCID: PMC7551347 DOI: 10.3390/md18090464] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/02/2020] [Accepted: 09/10/2020] [Indexed: 02/07/2023] Open
Abstract
The venom of various Conus species is composed of a rich variety of unique bioactive peptides, commonly referred to as conotoxins (conopeptides). Most conopeptides have specific receptors or ion channels as physiologically relevant targets. In this paper, high-throughput transcriptome sequencing was performed to analyze putative conotoxin transcripts from the venom duct of a vermivorous cone snail species, Conus litteratus native to the South China Sea. A total of 128 putative conotoxins were identified, most of them belonging to 22 known superfamilies, with 43 conotoxins being regarded as belonging to new superfamilies. Notably, the M superfamily was the most abundant in conotoxins among the known superfamilies. A total of 15 known cysteine frameworks were also described. The largest proportion of cysteine frameworks were VI/VII (C-C-CC-C-C), IX (C-C-C-C-C-C) and XIV (C-C-C-C). In addition, five novel cysteine patterns were also discovered. Simple sequence repeat detection results showed that di-nucleotide was the major type of repetition, and the codon usage bias results indicated that the codon usage bias of the conotoxin genes was weak, but the M, O1, O2 superfamilies differed in codon preference. Gene cloning indicated that there was no intron in conotoxins of the B1- or J superfamily, one intron with 1273-1339 bp existed in a mature region of the F superfamily, which is different from the previously reported gene structure of conotoxins from other superfamilies. This study will enhance our understanding of conotoxin diversity, and the new conotoxins discovered in this paper will provide more potential candidates for the development of pharmacological probes and marine peptide drugs.
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Liu C, Li T, Chen J. Role of High‐Throughput Electrophysiology in Drug Discovery. ACTA ACUST UNITED AC 2019; 87:e69. [DOI: 10.1002/cpph.69] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Chang Liu
- Department of Biochemical and Cellular PharmacologyGenentech Early Research and Development, Genentech South San Francisco California
| | - Tianbo Li
- Department of Biochemical and Cellular PharmacologyGenentech Early Research and Development, Genentech South San Francisco California
| | - Jun Chen
- Department of Biochemical and Cellular PharmacologyGenentech Early Research and Development, Genentech South San Francisco California
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Yang X, Wang Y, Wu C, Ling EA. Animal Venom Peptides as a Treasure Trove for New Therapeutics Against Neurodegenerative Disorders. Curr Med Chem 2019; 26:4749-4774. [PMID: 30378475 DOI: 10.2174/0929867325666181031122438] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/08/2018] [Accepted: 10/24/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and cerebral ischemic stroke, impose enormous socio-economic burdens on both patients and health-care systems. However, drugs targeting these diseases remain unsatisfactory, and hence there is an urgent need for the development of novel and potent drug candidates. METHODS Animal toxins exhibit rich diversity in both proteins and peptides, which play vital roles in biomedical drug development. As a molecular tool, animal toxin peptides have not only helped clarify many critical physiological processes but also led to the discovery of novel drugs and clinical therapeutics. RESULTS Recently, toxin peptides identified from venomous animals, e.g. exenatide, ziconotide, Hi1a, and PcTx1 from spider venom, have been shown to block specific ion channels, alleviate inflammation, decrease protein aggregates, regulate glutamate and neurotransmitter levels, and increase neuroprotective factors. CONCLUSION Thus, components of venom hold considerable capacity as drug candidates for the alleviation or reduction of neurodegeneration. This review highlights studies evaluating different animal toxins, especially peptides, as promising therapeutic tools for the treatment of different neurodegenerative diseases and disorders.
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Affiliation(s)
- Xinwang Yang
- Department of Anatomy and Histology & Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming 650500, Yunnan, China
| | - Ying Wang
- Key Laboratory of Chemistry in Ethnic Medicine Resource, State Ethnic Affairs Commission & Ministry of Education, School of Ethnomedicine and Ethnopharmacy, Yunnan Minzu University, Kunming 650500, Yunnan, China
| | - Chunyun Wu
- Department of Anatomy and Histology & Embryology, Faculty of Basic Medical Science, Kunming Medical University, Kunming 650500, Yunnan, China
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
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3D Printed Lab-on-a-Chip Platform for Chemical Stimulation and Parallel Analysis of Ion Channel Function. MICROMACHINES 2019; 10:mi10080548. [PMID: 31430884 PMCID: PMC6722671 DOI: 10.3390/mi10080548] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/06/2019] [Accepted: 08/16/2019] [Indexed: 12/27/2022]
Abstract
Functional imaging has been a widely established method for the assessment of ion channel function in vitro. Conventional infrastructure used for in vitro functional analysis of ion channels is typically proprietary, non-customizable, expensive, and requires a high level of skill to use and maintain. 3D desktop printing, which is employed in the rapid prototyping field, allows for quick engineering of alternatives to conventional imaging infrastructure that are customizable, low cost, and user friendly. Here, we describe an ultra-low-cost microfluidic lab-on-a-chip (LOC) device manufactured using acrylonitrile butadiene styrene (ABS) for in vitro functional imaging of ion channels that can quickly and easily be reconstructed using three-dimensional (3D) desktop printing. The device is light weight (<5 g), small (20 mm × 49 mm), and extremely low cost (<EUR 1). We simulate fluidics within the printed channels and assess the suitability of the engineered chamber to generate homogeneous mixtures during solution exchange. We demonstrate the usability of the 3D printed microfluidic device in a case study using Fluo-4-loaded human embryonal kidney-derived (HEK293) cells, recombinantly expressing the capsaicin receptor, transient receptor potential vanilloid receptor type 1 (TRPV1), as a model system. In the case study, we confirm its applicability to solution exchange for chemical stimulation and parallel functional time-lapse fluorescence microscopy-based calcium imaging. We assess the suitability of ABS for culturing HEK293 cells inside the microfluidic LOC, based on qualitative analysis of microscopic transmission light images of ABS-exposed HEK293 cells and confirm the previously reported biocompatibility of ABS. To highlight the versatility of the 3D printed microfluidic device, we provide an example for multiplication of the shown concept within a 3D printed multichannel microfluidic LOC to be used, for example, in a higher throughput format for parallelized functional analysis of ion channels. While this work focusses on Ca2+ imaging with TRPV1 channels, the device may also be useful for application with other ion channel types and in vitro models.
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12
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Berezhkovskii AM, Dagdug L, Bezrukov SM. Two-site versus continuum diffusion model of blocker dynamics in a membrane channel: Comparative analysis of escape kinetics. J Chem Phys 2019. [DOI: 10.1063/1.5110489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Alexander M. Berezhkovskii
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
- Mathematical and Statistical Computing Laboratory, Office of Intramural Research, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Leonardo Dagdug
- Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, 09340 Mexico City, Mexico
| | - Sergey M. Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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13
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Kazemi SM, Sabatier JM. Venoms of Iranian Scorpions (Arachnida, Scorpiones) and Their Potential for Drug Discovery. Molecules 2019; 24:molecules24142670. [PMID: 31340554 PMCID: PMC6680535 DOI: 10.3390/molecules24142670] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 07/16/2019] [Accepted: 07/20/2019] [Indexed: 12/19/2022] Open
Abstract
Scorpions, a characteristic group of arthropods, are among the earliest diverging arachnids, dating back almost 440 million years. One of the many interesting aspects of scorpions is that they have venom arsenals for capturing prey and defending against predators, which may play a critical role in their evolutionary success. Unfortunately, however, scorpion envenomation represents a serious health problem in several countries, including Iran. Iran is acknowledged as an area with a high richness of scorpion species and families. The diversity of the scorpion fauna in Iran is the subject of this review, in which we report a total of 78 species and subspecies in 19 genera and four families. We also list some of the toxins or genes studied from five species, including Androctonus crassicauda, Hottentotta zagrosensis, Mesobuthus phillipsi, Odontobuthus doriae, and Hemiscorpius lepturus, in the Buthidae and Hemiscorpiidae families. Lastly, we review the diverse functions of typical toxins from the Iranian scorpion species, including their medical applications.
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Affiliation(s)
- Seyed Mahdi Kazemi
- Zagros Herpetological Institute, No 12, Somayyeh 14 Avenue, 3715688415 Qom, Iran.
| | - Jean-Marc Sabatier
- Institute of NeuroPhysiopathology, UMR 7051, Faculté de Médecine Secteur Nord, 51, Boulevard Pierre Dramard-CS80011, 13344-Marseille Cedex 15, France
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14
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Bedoya M, Rinné S, Kiper AK, Decher N, González W, Ramírez D. TASK Channels Pharmacology: New Challenges in Drug Design. J Med Chem 2019; 62:10044-10058. [PMID: 31260312 DOI: 10.1021/acs.jmedchem.9b00248] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Rational drug design targeting ion channels is an exciting and always evolving research field. New medicinal chemistry strategies are being implemented to explore the wild chemical space and unravel the molecular basis of the ion channels modulators binding mechanisms. TASK channels belong to the two-pore domain potassium channel family and are modulated by extracellular acidosis. They are extensively distributed along the cardiovascular and central nervous systems, and their expression is up- and downregulated in different cancer types, which makes them an attractive therapeutic target. However, TASK channels remain unexplored, and drugs designed to target these channels are poorly selective. Here, we review TASK channels properties and their known blockers and activators, considering the new challenges in ion channels drug design and focusing on the implementation of computational methodologies in the drug discovery process.
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Affiliation(s)
- Mauricio Bedoya
- Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior, MCMBB , Philipps-University of Marburg , Deutschhausstraße 2 , Marburg 35037 , Germany
| | - Wendy González
- Centro de Bioinformática y Simulación Molecular (CBSM) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile.,Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD) , Universidad de Talca , 1 Poniente No. 1141 , 3460000 Talca , Chile
| | - David Ramírez
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud , Universidad Autónoma de Chile , El Llano Subercaseaux 2801, Piso 6 , 8900000 Santiago , Chile
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15
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Haustrate A, Hantute-Ghesquier A, Prevarskaya N, Lehen'kyi V. Monoclonal Antibodies Targeting Ion Channels and Their Therapeutic Potential. Front Pharmacol 2019; 10:606. [PMID: 31231216 PMCID: PMC6561378 DOI: 10.3389/fphar.2019.00606] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 05/14/2019] [Indexed: 12/27/2022] Open
Abstract
Monoclonal antibodies (mAbs) represent a rapidly growing pharmaceutical class of protein drugs that becomes an important part of the precision therapy. mAbs are characterized by their high specificity and affinity for the target antigen, which is mostly present on the cell surface. Ion channels are a large family of transmembrane proteins that control ion transport across the cell membrane. They are involved in almost all biological processes in both health and disease and are widely considered as prospective targets. However, no antibody-based drug targeting ion channel has been developed so far that has progressed to clinical use. Thus, we provide a comprehensive review of the elaborated mAbs against ion channels, describe their mechanisms of action, and discuss their therapeutic potential.
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Affiliation(s)
- Aurélien Haustrate
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channel Science and Therapeutics, Department of Biology, Faculty of Science and Technologies, University of Lille, Villeneuve d'Ascq, France
| | - Aline Hantute-Ghesquier
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channel Science and Therapeutics, Department of Biology, Faculty of Science and Technologies, University of Lille, Villeneuve d'Ascq, France
| | - Natalia Prevarskaya
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channel Science and Therapeutics, Department of Biology, Faculty of Science and Technologies, University of Lille, Villeneuve d'Ascq, France
| | - V'yacheslav Lehen'kyi
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channel Science and Therapeutics, Department of Biology, Faculty of Science and Technologies, University of Lille, Villeneuve d'Ascq, France.,FONDATION ARC, Villejuif, France
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16
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Berezhkovskii AM, Bezrukov SM. Blocker escape kinetics from a membrane channel analyzed by mapping blocker diffusive dynamics onto a two-site model. J Chem Phys 2019; 150:194103. [PMID: 31117787 DOI: 10.1063/1.5095594] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
When a large solute molecule enters a membrane channel from the membrane-bathing electrolyte solution, it blocks the small-ion current flowing through the channel. If the molecule spends in the channel sufficiently long time, individual blockades can be resolved in single-channel experiments. In this paper, we develop an analytical theory of the blocker escape kinetics from the channel, assuming that a charged blocking molecule cannot pass through a constriction region (bottleneck). We focus on the effect of the external voltage bias on the blocker survival probability in the channel. The bias creates a potential well for the charged blocker in the channel with the minimum located near the bottleneck. When the bias is strong, the well is deep, and escape from the channel is a slow process that allows for time-resolved observation of individual blocking events. Our analysis is performed in the framework of a two-site model of the blocker dynamics in the channel. Importantly, the rate constants, fully determining this model, are derived from a more realistic continuum diffusion model. This is done by mapping the latter onto its two-site counterpart which, while being much simpler, captures the main features of the blocker escape kinetics at high biases.
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Affiliation(s)
- Alexander M Berezhkovskii
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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17
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D'Arcangelo D, Scatozza F, Giampietri C, Marchetti P, Facchiano F, Facchiano A. Ion Channel Expression in Human Melanoma Samples: In Silico Identification and Experimental Validation of Molecular Targets. Cancers (Basel) 2019; 11:cancers11040446. [PMID: 30934896 PMCID: PMC6520727 DOI: 10.3390/cancers11040446] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 03/20/2019] [Accepted: 03/23/2019] [Indexed: 12/30/2022] Open
Abstract
Expression of 328 ion channel genes was investigated, by in silico analysis, in 170 human melanoma samples and controls. Ninety-one members of this gene-family (i.e., about 28%) show a significant (p < 0.05) differential expression in melanoma- vs. nevi-biopsies, taken from the GEO database. ROC (receiver operating characteristic) analysis selected 20 genes as potential markers showing the highest discrimination ability of melanoma vs. nevi (AUC > 0.90 and p < 0.0001). These 20 genes underwent a first in silico-validation round in an independent patients-dataset from GEO. A second-in silico-validation step was then carried out on a third human dataset in Oncomine. Finally, five genes were validated, showing extremely high sensitivity and specificity in melanoma detection (>90% in most cases). Such five genes (namely, SCNN1A, GJB3, KCNK7, GJB1, KCNN2) are novel potential melanoma markers or molecular targets, never previously related to melanoma. The “druggable genome” analysis was then carried out. Miconazole, an antifungal drug commonly used in clinics, is known to target KCNN2, the best candidate among the five identified genes. Miconazole was then tested in vitro in proliferation assays; it dose-dependently inhibited proliferation up to 90% and potently induced cell-death in A-375 and SKMEL-28 melanoma cells, while it showed no effect in control cells. Moreover, specific silencing of KCNN2 ion channel was achieved by siRNA transfection; under such condition miconazole strongly increases its anti-proliferative effect. In conclusion, the present study identified five ion channels that can potentially serve as sensitive and specific markers in human melanoma specimens and demonstrates that the antifungal drug miconazole, known to target one of the five identified ion channels, exerts strong and specific anti-melanoma effects in vitro.
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Affiliation(s)
| | | | - Claudia Giampietri
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Unit of Histology and Medical Embryology, Sapienza University of Rome, 00161 Rome, Italy.
| | - Paolo Marchetti
- Medical Oncology, Sapienza, University of Rome, 00161 Rome, Italy.
| | - Francesco Facchiano
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità (ISS), 00161 Rome, Italy.
| | - Antonio Facchiano
- Istituto Dermopatico dell'Immacolata (IDI-IRCCS), 00167 Rome, Italy.
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18
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Abstract
Ion channels facilitate the movement of ions across the plasma and organellar membranes. A recent symposium brought together scientists who study ion channels and transporters in immune cells, which highlighted advances in this emerging field and served to chart new avenues for investigating the roles of ion channels in immunity.
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Affiliation(s)
- Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
| | - Axel R Concepcion
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - William A Coetzee
- Department of Pediatrics, New York University School of Medicine, New York, NY 10016, USA.
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19
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Abstract
It is now well established that antibodies have numerous potential benefits when developed as therapeutics. Here, we evaluate the technical challenges of raising antibodies to membrane-spanning proteins together with enabling technologies that may facilitate the discovery of antibody therapeutics to ion channels. Additionally, we discuss the potential targeting opportunities in the anti-ion channel antibody landscape, along with a number of case studies where functional antibodies that target ion channels have been reported. Antibodies currently in development and progressing towards the clinic are highlighted.
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Affiliation(s)
| | - Paul Colussi
- a TetraGenetics Inc , Arlington Massachusetts , USA
| | - Theodore G Clark
- a TetraGenetics Inc , Arlington Massachusetts , USA.,b Department of Microbiology and Immunology , Cornell University , Ithaca New York , USA
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20
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Berezhkovskii AM, Bezrukov SM. Mapping Intrachannel Diffusive Dynamics of Interacting Molecules onto a Two-Site Model: Crossover in Flux Concentration Dependence. J Phys Chem B 2018; 122:10996-11001. [PMID: 29957941 DOI: 10.1021/acs.jpcb.8b04371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study focuses on how interactions of solute molecules affect the concentration dependence of their flux through narrow membrane channels. It is assumed that the molecules cannot bypass each other because of their hard-core repulsion. In addition, other short- and long-range solute-solute interactions are included into consideration. These interactions make it impossible to develop an analytical theory for the flux in the framework of a diffusion model of solute dynamics in the channel. To overcome this difficulty, we course-grain the diffusion model by mapping it onto a two-site one, where the rate constants describing the solute dynamics are expressed in terms of the parameters of the initial diffusion model. This allows us (i) to find an analytical solution for the flux as a function of the solute concentration and (ii) to characterize the solute-solute interactions by two dimensionless parameters. Such a characterization proves to be very informative as it results in a clear classification of the effects of the solute-solute interactions on the concentration dependence of the flux. Unexpectedly, this dependence can be nonmonotonic, exhibiting a sharp maximum in a certain parameter range. We hypothesize that such a behavior may constitute an element of a regulatory mechanism, wherein maximal flux reports on the optimal solute concentration in the bulk near the channel entrance.
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Affiliation(s)
- Alexander M Berezhkovskii
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development , National Institutes of Health , Bethesda , Maryland 20892 , United States.,Mathematical and Statistical Computing Laboratory, Division for Computational Bioscience, Center for Information Technology , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development , National Institutes of Health , Bethesda , Maryland 20892 , United States
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21
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Mechanism-specific assay design facilitates the discovery of Nav1.7-selective inhibitors. Proc Natl Acad Sci U S A 2018; 115:E792-E801. [PMID: 29311306 PMCID: PMC5789920 DOI: 10.1073/pnas.1713701115] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Subtype-selective modulation of ion channels is often important, but extremely difficult to achieve for drug development. Using Nav1.7 as an example, we show that this challenge could be attributed to poor design in ion channel assays, which fail to detect most potent and selective compounds and are biased toward nonselective mechanisms. By exploiting different drug binding sites and modes of channel gating, we successfully direct a membrane potential assay toward non–pore-blocking mechanisms and identify Nav1.7-selective compounds. Our mechanistic approach to assay design addresses a significant hurdle in Nav1.7 drug discovery and is applicable to many other ion channels. Many ion channels, including Nav1.7, Cav1.3, and Kv1.3, are linked to human pathologies and are important therapeutic targets. To develop efficacious and safe drugs, subtype-selective modulation is essential, but has been extremely difficult to achieve. We postulate that this challenge is caused by the poor assay design, and investigate the Nav1.7 membrane potential assay, one of the most extensively employed screening assays in modern drug discovery. The assay uses veratridine to activate channels, and compounds are identified based on the inhibition of veratridine-evoked activities. We show that this assay is biased toward nonselective pore blockers and fails to detect the most potent, selective voltage-sensing domain 4 (VSD4) blockers, including PF-05089771 (PF-771) and GX-936. By eliminating a key binding site for pore blockers and replacing veratridine with a VSD-4 binding activator, we directed the assay toward non–pore-blocking mechanisms and discovered Nav1.7-selective chemical scaffolds. Hence, we address a major hurdle in Nav1.7 drug discovery, and this mechanistic approach to assay design is applicable to Cav3.1, Kv1.3, and many other ion channels to facilitate drug discovery.
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22
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Wilson D, Boyle GM, McIntyre L, Nolan MJ, Parsons PG, Smith JJ, Tribolet L, Loukas A, Liddell MJ, Rash LD, Daly NL. The Aromatic Head Group of Spider Toxin Polyamines Influences Toxicity to Cancer Cells. Toxins (Basel) 2017; 9:toxins9110346. [PMID: 29077051 PMCID: PMC5705961 DOI: 10.3390/toxins9110346] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/22/2017] [Accepted: 10/23/2017] [Indexed: 01/08/2023] Open
Abstract
Spider venoms constitute incredibly diverse libraries of compounds, many of which are involved in prey capture and defence. Polyamines are often prevalent in the venom and target ionotropic glutamate receptors. Here we show that a novel spider polyamine, PA366, containing a hydroxyphenyl-based structure is present in the venom of several species of tarantula, and has selective toxicity against MCF-7 breast cancer cells. By contrast, a polyamine from an Australian funnel-web spider venom, which contains an identical polyamine tail to PA366 but an indole-based head-group, is only cytotoxic at high concentrations. Our results suggest that the ring structure plays a role in the cytotoxicity and that modification to the polyamine head group might lead to more potent and selective compounds with potential as novel cancer treatments.
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Affiliation(s)
- David Wilson
- Centre for Biodiscovery and Molecular Development of Therapeutics, AITHM, James Cook University, Cairns, QLD 4878, Australia.
| | - Glen M Boyle
- QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia.
| | - Lachlan McIntyre
- Centre for Tropical Environmental and Sustainable Sciences, James Cook University, Cairns, QLD 4878, Australia.
| | - Matthew J Nolan
- Centre for Biodiscovery and Molecular Development of Therapeutics, AITHM, James Cook University, Cairns, QLD 4878, Australia.
| | - Peter G Parsons
- QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia.
| | - Jennifer J Smith
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Leon Tribolet
- Centre for Biodiscovery and Molecular Development of Therapeutics, AITHM, James Cook University, Cairns, QLD 4878, Australia.
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, AITHM, James Cook University, Cairns, QLD 4878, Australia.
| | - Michael J Liddell
- Centre for Tropical Environmental and Sustainable Sciences, James Cook University, Cairns, QLD 4878, Australia.
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
| | - Norelle L Daly
- Centre for Biodiscovery and Molecular Development of Therapeutics, AITHM, James Cook University, Cairns, QLD 4878, Australia.
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23
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Liu D, Tseng M, Epstein LF, Green L, Chan B, Soriano B, Lim D, Pan O, Murawsky CM, King CT, Moyer BD. Evaluation of recombinant monoclonal antibody SVmab1 binding to Na V1.7 target sequences and block of human Na V1.7 currents. F1000Res 2016; 5:2764. [PMID: 27990272 PMCID: PMC5155501 DOI: 10.12688/f1000research.9918.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/11/2016] [Indexed: 01/16/2023] Open
Abstract
Identification of small and large molecule pain therapeutics that target the genetically validated voltage-gated sodium channel Na
V1.7 is a challenging endeavor under vigorous pursuit. The monoclonal antibody SVmab1 was recently published to bind the Na
V1.7 DII voltage sensor domain and block human Na
V1.7 sodium currents in heterologous cells. We produced purified SVmab1 protein based on publically available sequence information, and evaluated its activity in a battery of binding and functional assays. Herein, we report that our recombinant SVmAb1 does not bind peptide immunogen or purified Na
V1.7 DII voltage sensor domain via ELISA, and does not bind Na
V1.7 in live HEK293, U-2 OS, and CHO-K1 cells via FACS. Whole cell manual patch clamp electrophysiology protocols interrogating diverse Na
V1.7 gating states in HEK293 cells, revealed that recombinant SVmab1 does not block Na
V1.7 currents to an extent greater than observed with an isotype matched control antibody. Collectively, our results show that recombinant SVmab1 monoclonal antibody does not bind Na
V1.7 target sequences or specifically inhibit Na
V1.7 current.
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Affiliation(s)
- Dong Liu
- Neuroscience, Amgen Inc., Thousand Oaks, USA
| | | | | | | | | | - Brian Soriano
- Discovery Attribute Sciences, Amgen Inc., Thousand Oaks, USA
| | | | - Oscar Pan
- Amgen British Columbia, Burnaby, Canada
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24
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Pal K, Gangopadhyay G. Probing kinetic drug binding mechanism in voltage-gated sodium ion channel: open state versus inactive state blockers. Channels (Austin) 2016; 9:307-16. [PMID: 26274618 DOI: 10.1080/19336950.2015.1078950] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The kinetics and nonequilibrium thermodynamics of open state and inactive state drug binding mechanisms have been studied here using different voltage protocols in sodium ion channel. We have found that for constant voltage protocol, open state block is more efficient in blocking ionic current than inactive state block. Kinetic effect comes through peak current for mexiletine as an open state blocker and in the tail part for lidocaine as an inactive state blocker. Although the inactivation of sodium channel is a free energy driven process, however, the two different kinds of drug affect the inactivation process in a different way as seen from thermodynamic analysis. In presence of open state drug block, the process initially for a long time remains entropy driven and then becomes free energy driven. However in presence of inactive state block, the process remains entirely entropy driven until the equilibrium is attained. For oscillating voltage protocol, the inactive state blocking is more efficient in damping the oscillation of ionic current. From the pulse train analysis it is found that inactive state blocking is less effective in restoring normal repolarisation and blocks peak ionic current. Pulse train protocol also shows that all the inactive states behave differently as one inactive state responds instantly to the test pulse in an opposite manner from the other two states.
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Affiliation(s)
- Krishnendu Pal
- a S.N. Bose National Center for Basic Sciences ; Block-JD; Sector-III; Salt Lake; Kolkata , India
| | - Gautam Gangopadhyay
- a S.N. Bose National Center for Basic Sciences ; Block-JD; Sector-III; Salt Lake; Kolkata , India
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25
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Kuzmenkov AI, Krylov NA, Chugunov AO, Grishin EV, Vassilevski AA. Kalium: a database of potassium channel toxins from scorpion venom. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2016; 2016:baw056. [PMID: 27087309 PMCID: PMC4834203 DOI: 10.1093/database/baw056] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/20/2016] [Indexed: 12/16/2022]
Abstract
Kalium (http://kaliumdb.org/) is a manually curated database that accumulates data on potassium channel toxins purified from scorpion venom (KTx). This database is an open-access resource, and provides easy access to pages of other databases of interest, such as UniProt, PDB, NCBI Taxonomy Browser, and PubMed. General achievements of Kalium are a strict and easy regulation of KTx classification based on the unified nomenclature supported by researchers in the field, removal of peptides with partial sequence and entries supported by transcriptomic information only, classification of β-family toxins, and addition of a novel λ-family. Molecules presented in the database can be processed by the Clustal Omega server using a one-click option. Molecular masses of mature peptides are calculated and available activity data are compiled for all KTx. We believe that Kalium is not only of high interest to professional toxinologists, but also of general utility to the scientific community. Database URL: http://kaliumdb.org/
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Affiliation(s)
- Alexey I Kuzmenkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Nikolay A Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia Joint Supercomputer Center, Russian Academy of Sciences, Moscow 119991, Russia
| | - Anton O Chugunov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Eugene V Grishin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Alexander A Vassilevski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
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Bezrukov SM, Nestorovich EM. Inhibiting bacterial toxins by channel blockage. Pathog Dis 2016; 74:ftv113. [PMID: 26656888 PMCID: PMC4830228 DOI: 10.1093/femspd/ftv113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/15/2015] [Accepted: 11/24/2015] [Indexed: 01/01/2023] Open
Abstract
Emergent rational drug design techniques explore individual properties of target biomolecules, small and macromolecule drug candidates, and the physical forces governing their interactions. In this minireview, we focus on the single-molecule biophysical studies of channel-forming bacterial toxins that suggest new approaches for their inhibition. We discuss several examples of blockage of bacterial pore-forming and AB-type toxins by the tailor-made compounds. In the concluding remarks, the most effective rationally designed pore-blocking antitoxins are compared with the small-molecule inhibitors of ion-selective channels of neurophysiology.
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Affiliation(s)
- Sergey M Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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Robertson DN, Sleno R, Nagi K, Pétrin D, Hébert TE, Pineyro G. Design and construction of conformational biosensors to monitor ion channel activation: A prototype FlAsH/BRET-approach to Kir3 channels. Methods 2016. [DOI: 10.1016/j.ymeth.2015.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Zhang Y. Why do we study animal toxins? DONG WU XUE YAN JIU = ZOOLOGICAL RESEARCH 2015; 36:183-222. [PMID: 26228472 PMCID: PMC4790257 DOI: 10.13918/j.issn.2095-8137.2015.4.183] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/25/2015] [Indexed: 12/31/2022]
Abstract
Venom (toxins) is an important trait evolved along the evolutionary tree of animals. Our knowledges on venoms, such as their origins and loss, the biological relevance and the coevolutionary patterns with other organisms are greatly helpful in understanding many fundamental biological questions, i.e., the environmental adaptation and survival competition, the evolution shaped development and balance of venoms, and the sophisticated correlations among venom, immunity, body power, intelligence, their genetic basis, inherent association, as well as the cost-benefit and trade-offs of biological economy. Lethal animal envenomation can be found worldwide. However, from foe to friend, toxin studies have led lots of important discoveries and exciting avenues in deciphering and fighting human diseases, including the works awarded the Nobel Prize and lots of key clinic therapeutics. According to our survey, so far, only less than 0.1% of the toxins of the venomous animals in China have been explored. We emphasize on the similarities shared by venom and immune systems, as well as the studies of toxin knowledge-based physiological toxin-like proteins/peptides (TLPs). We propose the natural pairing hypothesis. Evolution links toxins with humans. Our mission is to find out the right natural pairings and interactions of our body elements with toxins, and with endogenous toxin-like molecules. Although, in nature, toxins may endanger human lives, but from a philosophical point of view, knowing them well is an effective way to better understand ourselves. So, this is why we study toxins.
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Affiliation(s)
- Yun Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming Yunnan 650223,
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Du Y, Days E, Romaine I, Abney KK, Kaufmann K, Sulikowski G, Stauffer S, Lindsley CW, Weaver CD. Development and validation of a thallium flux-based functional assay for the sodium channel NaV1.7 and its utility for lead discovery and compound profiling. ACS Chem Neurosci 2015; 6:871-8. [PMID: 25879403 DOI: 10.1021/acschemneuro.5b00004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ion channels are critical for life, and they are targets of numerous drugs. The sequencing of the human genome has revealed the existence of hundreds of different ion channel subunits capable of forming thousands of ion channels. In the face of this diversity, we only have a few selective small-molecule tools to aid in our understanding of the role specific ion channels in physiology which may in turn help illuminate their therapeutic potential. Although the advent of automated electrophysiology has increased the rate at which we can screen for and characterize ion channel modulators, the technique's high per-measurement cost and moderate throughput compared to other high-throughput screening approaches limit its utility for large-scale high-throughput screening. Therefore, lower cost, more rapid techniques are needed. While ion channel types capable of fluxing calcium are well-served by low cost, very high-throughput fluorescence-based assays, other channel types such as sodium channels remain underserved by present functional assay techniques. In order to address this shortcoming, we have developed a thallium flux-based assay for sodium channels using the NaV1.7 channel as a model target. We show that the assay is able to rapidly and cost-effectively identify NaV1.7 inhibitors thus providing a new method useful for the discovery and profiling of sodium channel modulators.
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Affiliation(s)
| | | | | | - Kris K. Abney
- Meharry Medical
College Program in Pharmacology, Nashville, Tennessee 37208, United States
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Zuliani V, Rapalli A, Patel MK, Rivara M. Sodium channel blockers: a patent review (2010 – 2014). Expert Opin Ther Pat 2014; 25:279-90. [DOI: 10.1517/13543776.2014.995628] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Wilkinson TCI, Gardener MJ, Williams WA. Discovery of Functional Antibodies Targeting Ion Channels. ACTA ACUST UNITED AC 2014; 20:454-67. [DOI: 10.1177/1087057114560698] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ion channels play critical roles in physiology and disease by modulation of cellular functions such as electrical excitability, secretion, cell migration, and gene transcription. Ion channels represent an important target class for drug discovery that has been largely addressed, to date, using small-molecule approaches. A significant opportunity exists to target these channels with antibodies and alternative formats of biologics. Antibodies display high specificity and affinity for their target antigen, and they have the potential to target ion channels very selectively. Nevertheless, isolating antibodies to this target class is challenging due to the difficulties in expression and purification of ion channels in a format suitable for antibody drug discovery in addition to the complexity of screening for function. In this article, we will review the current state of ion channel biologics discovery and the progress that has been made. We will also highlight the challenges in isolating functional antibodies to these targets and how these challenges may be addressed. Finally, we also illustrate successful approaches to isolating functional monoclonal antibodies targeting ion channels by way of a number of case studies drawn from recent publications.
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Affiliation(s)
| | | | - Wendy A. Williams
- Antibody Discovery and Protein Engineering, MedImmune, Cambridge, UK
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Kalia J, Milescu M, Salvatierra J, Wagner J, Klint JK, King GF, Olivera BM, Bosmans F. From foe to friend: using animal toxins to investigate ion channel function. J Mol Biol 2014; 427:158-175. [PMID: 25088688 DOI: 10.1016/j.jmb.2014.07.027] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 12/19/2022]
Abstract
Ion channels are vital contributors to cellular communication in a wide range of organisms, a distinct feature that renders this ubiquitous family of membrane-spanning proteins a prime target for toxins found in animal venom. For many years, the unique properties of these naturally occurring molecules have enabled researchers to probe the structural and functional features of ion channels and to define their physiological roles in normal and diseased tissues. To illustrate their considerable impact on the ion channel field, this review will highlight fundamental insights into toxin-channel interactions and recently developed toxin screening methods and practical applications of engineered toxins.
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Affiliation(s)
- Jeet Kalia
- Indian Institute of Science Education and Research Pune; Pune, Maharashtra 411 008 India
| | - Mirela Milescu
- Division of Biological Sciences; University of Missouri, Columbia, MO 65211 USA
| | - Juan Salvatierra
- Department of Physiology; Johns Hopkins University, School of Medicine, Baltimore, MD 21205 USA
| | - Jordan Wagner
- Department of Physiology; Johns Hopkins University, School of Medicine, Baltimore, MD 21205 USA
| | - Julie K Klint
- Institute for Molecular Bioscience; The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Glenn F King
- Institute for Molecular Bioscience; The University of Queensland, St. Lucia, QLD 4072 Australia
| | | | - Frank Bosmans
- Department of Physiology; Johns Hopkins University, School of Medicine, Baltimore, MD 21205 USA.,Solomon H. Snyder Department of Neuroscience; Johns Hopkins University, School of Medicine, Baltimore, MD 21205 USA
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Bruhn BR, Liu H, Schuhladen S, Hunt AJ, Mordovanakis A, Mayer M. Dual-pore glass chips for cell-attached single-channel recordings. LAB ON A CHIP 2014; 14:2410-7. [PMID: 24844315 PMCID: PMC4121072 DOI: 10.1039/c4lc00370e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
While high-throughput planar patch-clamp instruments are now established to perform whole-cell recordings for drug screening, the conventional micropipette-based approach remains the gold standard for performing cell-attached single-channel recordings. Generally, planar platforms are not well-suited for such studies due to excess noise resulting from low seal resistances and the use of substrates with poor dielectric properties. Since these platforms tend to use the same pore to position a cell by suction and establish a seal, biological debris from the cell suspension can contaminate the pore surface prior to seal formation, reducing the seal resistance. Here, femtosecond laser ablation was used to fabricate dual-pore glass chips optimized for use in cell-attached single-channel recordings that circumvent this problem by using different pores to position a cell and to establish a seal. This dual-pore design also permitted the use of a relatively small patch aperture (D ~ 150 to 300 nm) that is better-suited for establishing high-resistance seals than the micropores used typically in planar patch-clamp setups (D ~ 1 to 2 μm) without compromising the ability of the device to position a cell. Taking advantage of the high seal resistances and low capacitive and dielectric noise realized using glass substrates, patch-clamp experiments with these dual-pore chips consistently achieved high seal resistances (rate of gigaseal formation = 61%, mean seal resistance = 53 GΩ), maintained gigaseals for prolonged durations (up to 6 hours), achieved RMS noise values as low as 0.46 pA at 5 kHz bandwidth, and enabled single-channel recordings in the cell-attached configuration that are comparable to those obtained by conventional patch-clamp.
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Affiliation(s)
- Brandon R Bruhn
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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Sałat K, Kowalczyk P, Gryzło B, Jakubowska A, Kulig K. New investigational drugs for the treatment of neuropathic pain. Expert Opin Investig Drugs 2014; 23:1093-104. [DOI: 10.1517/13543784.2014.916688] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Kinga Sałat
- Jagiellonian University, Faculty of Pharmacy,
Medyczna 9 St., 30-688 Kraków, Poland
| | - Paula Kowalczyk
- Jagiellonian University, Department of Physicochemical Drug Analysis, Faculty of Pharmacy,
Medyczna 9 St., 30-688 Kraków, Poland
| | - Beata Gryzło
- Jagiellonian University, Department of Physicochemical Drug Analysis, Faculty of Pharmacy,
Medyczna 9 St., 30-688 Kraków, Poland
| | - Anna Jakubowska
- Jagiellonian University, Department of Physicochemical Drug Analysis, Faculty of Pharmacy,
Medyczna 9 St., 30-688 Kraków, Poland
| | - Katarzyna Kulig
- Jagiellonian University, Department of Physicochemical Drug Analysis, Faculty of Pharmacy,
Medyczna 9 St., 30-688 Kraków, Poland
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McPate M, Bhalay G, Beckett M, Fairbrother S, Gosling M, Groot-Kormelink PJ, Lane R, Kent T, Van Diepen MT, Tranter P, Verkuyl JM. The Development of Automated Patch Clamp Assays for Canonical Transient Receptor Potential Channels TRPC3, 6, and 7. Assay Drug Dev Technol 2014; 12:282-92. [PMID: 24906109 DOI: 10.1089/adt.2014.574] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Mark McPate
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Gurdip Bhalay
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Martin Beckett
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Sian Fairbrother
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Martin Gosling
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Paul J. Groot-Kormelink
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Rebecca Lane
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Toby Kent
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Michiel T. Van Diepen
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - Pamela Tranter
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
| | - J. Martin Verkuyl
- Novartis Institutes for BioMedical Research, Horsham Research Centre, West Sussex, United Kingdom
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Substituted 4-phenyl-2-aminoimidazoles and 4-phenyl-4,5-dihydro-2-aminoimidazoles as voltage-gated sodium channel modulators. Eur J Med Chem 2014; 74:23-30. [DOI: 10.1016/j.ejmech.2013.12.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/16/2013] [Accepted: 12/22/2013] [Indexed: 11/24/2022]
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Tanzi S, Matteucci M, Christiansen TL, Friis S, Christensen MT, Garnaes J, Wilson S, Kutchinsky J, Taboryski R. Ion channel recordings on an injection-molded polymer chip. LAB ON A CHIP 2013; 13:4784-4793. [PMID: 24154831 DOI: 10.1039/c3lc50760b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this paper, we demonstrate recordings of the ion channel activity across the cell membrane in a biological cell by employing the so-called patch clamping technique on an injection-molded polymer microfluidic device. The findings will allow direct recordings of ion channel activity to be made using the cheapest materials and production platform to date and with the potential for very high throughput. The employment of cornered apertures for cell capture allowed the fabrication of devices without through holes and via a scheme comprising master origination by dry etching in a silicon substrate, electroplating in nickel and injection molding of the final part. The most critical device parameters were identified as the length of the patching capillary and the very low surface roughness on the inside of the capillary. The cross-sectional shape of the orifice was found to be less critical, as both rectangular and semicircular profiles seemed to have almost the same ability to form tight seals with cells with negligible leak currents. The devices were functionally tested using human embryonic kidney cells expressing voltage-gated sodium channels (Nav1.7) and benchmarked against a commercial state-of-the-art system for automated ion channel recordings. These experiments considered current-voltage (IV) relationships for activation and inactivation of the Nav1.7 channels and their sensitivity to a local anesthetic, lidocaine. Both IVs and lidocaine dose-response curves obtained from the injection-molded polymer device were in good agreement with data obtained from the commercial system.
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Affiliation(s)
- Simone Tanzi
- Department of Micro- and Nanotechnology, Technical University of Denmark, Building 345E, DK-2800 Kongens Lyngby, Denmark.
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39
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Talwar S, Lynch JW, Gilbert DF. Fluorescence-based high-throughput functional profiling of ligand-gated ion channels at the level of single cells. PLoS One 2013; 8:e58479. [PMID: 23520514 PMCID: PMC3592791 DOI: 10.1371/journal.pone.0058479] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 02/06/2013] [Indexed: 12/26/2022] Open
Abstract
Ion channels are involved in many physiological processes and are attractive targets for therapeutic intervention. Their functional properties vary according to their subunit composition, which in turn varies in a developmental and tissue-specific manner and as a consequence of pathophysiological events. Understanding this diversity requires functional analysis of ion channel properties in large numbers of individual cells. Functional characterisation of ligand-gated channels involves quantitating agonist and drug dose-response relationships using electrophysiological or fluorescence-based techniques. Electrophysiology is limited by low throughput and high-throughput fluorescence-based functional evaluation generally does not enable the characterization of the functional properties of each individual cell. Here we describe a fluorescence-based assay that characterizes functional channel properties at single cell resolution in high throughput mode. It is based on progressive receptor activation and iterative fluorescence imaging and delivers >100 dose-responses in a single well of a 384-well plate, using α1-3 homomeric and αβ heteromeric glycine receptor (GlyR) chloride channels as a model system. We applied this assay with transiently transfected HEK293 cells co-expressing halide-sensitive yellow fluorescent protein and different GlyR subunit combinations. Glycine EC50 values of different GlyR isoforms were highly correlated with published electrophysiological data and confirm previously reported pharmacological profiles for the GlyR inhibitors, picrotoxin, strychnine and lindane. We show that inter and intra well variability is low and that clustering of functional phenotypes permits identification of drugs with subunit-specific pharmacological profiles. As this method dramatically improves the efficiency with which ion channel populations can be characterized in the context of cellular heterogeneity, it should facilitate systems-level analysis of ion channel properties in health and disease and the discovery of therapeutics to reverse pathological alterations.
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Affiliation(s)
- Sahil Talwar
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Joseph W. Lynch
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Daniel F. Gilbert
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
- * E-mail:
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Abstract
The study of P2X receptors has long been handicapped by a poverty of small-molecule tools that serve as selective agonists and antagonists. There has been progress, particularly in the past 10 years, as cell-based high-throughput screening methods were applied, together with large chemical libraries. This has delivered some drug-like molecules in several chemical classes that selectively target P2X1, P2X3, or P2X7 receptors. Some of these are, or have been, in clinical trials for rheumatoid arthritis, pain, and cough. Current preclinical research programs are studying P2X receptor involvement in pain, inflammation, osteoporosis, multiple sclerosis, spinal cord injury, and bladder dysfunction. The determination of the atomic structure of P2X receptors in closed and open (ATP-bound) states by X-ray crystallography is now allowing new approaches by molecular modeling. This is supported by a large body of previous work using mutagenesis and functional expression, and is now being supplemented by molecular dynamic simulations and in silico ligand docking. These approaches should lead to P2X receptors soon taking their place alongside other ion channel proteins as therapeutically important drug targets.
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Affiliation(s)
- R Alan North
- Faculty of Medical and Human Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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Abstract
INTRODUCTION The relict plastid, or apicoplast, is a characteristic feature of Plasmodium spp. and reflects the unusual evolutionary origins of these parasites. The essential role this organelle plays in the life of the parasite, and its unusual, non-mammalian metabolism, make the apicoplast an excellent drug target. AREAS COVERED This review focuses on the biological role of the apicoplast in the erythrocytic life cycle and what that reveals about existing drug targets. We also discuss the future of the apicoplast in the development of anti-malarials, emphasizing those pathways with greatest potential as a source of novel drug targets and emphasizing the need to understand in vitro drug responses to optimize eventual use of these drugs to treat malaria. EXPERT OPINION More than a decade of research on the apicoplast has confirmed the promise of this organelle as a source of drug targets. It is now possible to rationally assess the value of existing drugs and new drug targets, and to understand the role these drugs can play in the arsenal of anti-malarial treatments.
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Affiliation(s)
- Christopher D Goodman
- University of Melbourne, School of Botany, Professor's Walk, Parkville, Vic, 3010, Australia.
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