1
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Paul A, Roy PK, Babu NK, Singh S. Clotrimazole causes membrane depolarization and induces sub G 0 cell cycle arrest in Leishmania donovani. Acta Trop 2024; 252:107139. [PMID: 38307362 DOI: 10.1016/j.actatropica.2024.107139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 02/04/2024]
Abstract
Clotrimazole is an FDA approved drug and is widely used as an antifungal agent. An extensive body of research is available about its mechanism of action on various cell types but its mode of killing of Leishmania donovani parasites is unknown. L. donovani causes Visceral Leishmaniasis which is a public health problem with limited treatment options. Its present chemotherapy is expensive, has adverse effects and is plagued with drug resistance issues. In this study we have explored the possibility of repurposing clotrimazole as an antileishmanial drug. We have assessed its efficacy on the parasites and attempted to understand its mode of action. We found that it has a half-maximal inhibitory concentration (IC50) of 35.75 ± 1.06 μM, 12.75 ± 0.35 μM and 73 ± 1.41 μM in promastigotes, intracellular amastigotes and macrophages, respectively. Clotrimazole is 5.73 times more selective for the intracellular amastigotes as compared to the mammalian cell. Effect of clotrimazole was reduced by ergosterol supplementation. It leads to impaired parasite morphology. It alters plasma membrane permeability and disrupts plasma membrane potential. Mitochondrial function is compromised as is evident from increased ROS generation, depolarized mitochondrial membrane and decreased ATP levels. Cell cycle analysis of clotrimazole treated parasites shows arrest at sub-G0 phase suggesting apoptotic mode of cell death.
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Affiliation(s)
- Anindita Paul
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, Punjab 160062, India
| | - Pradyot Kumar Roy
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, Punjab 160062, India
| | - Neerupudi Kishore Babu
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, Punjab 160062, India
| | - Sushma Singh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, Punjab 160062, India.
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2
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Vasileva VY, Khairullina ZM, Sudarikova AV, Chubinskiy-Nadezhdin VI. Role of Calcium-Activated Potassium Channels in Proliferation, Migration and Invasion of Human Chronic Myeloid Leukemia K562 Cells. MEMBRANES 2023; 13:583. [PMID: 37367787 DOI: 10.3390/membranes13060583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/02/2023] [Accepted: 06/02/2023] [Indexed: 06/28/2023]
Abstract
Calcium-activated potassium channels (KCa) are important participants in calcium signaling pathways due to their ability to be activated by an increase in intracellular free calcium concentration. KCa channels are involved in the regulation of cellular processes in both normal and pathophysiological conditions, including oncotransformation. Previously, using patch-clamp, we registered the KCa currents in the plasma membrane of human chronic myeloid leukemia K562 cells, whose activity was controlled by local Ca2+ entry via mechanosensitive calcium-permeable channels. Here, we performed the molecular and functional identification of KCa channels and have uncovered their role in the proliferation, migration and invasion of K562 cells. Using a combined approach, we identified the functional activity of SK2, SK3 and IK channels in the plasma membrane of the cells. Selective SK and IK channel inhibitors, apamin and TRAM-34, respectively, reduced the proliferative, migratory and invasive capabilities of human myeloid leukemia cells. At the same time, the viability of K562 cells was not affected by KCa channel inhibitors. Ca2+ imaging showed that both SK and IK channel inhibitors affect Ca2+ entry and this could underlie the observed suppression of pathophysiological reactions of K562 cells. Our data imply that SK/IK channel inhibitors could be used to slow down the proliferation and spreading of chronic myeloid leukemia K562 cells that express functionally active KCa channels in the plasma membrane.
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Affiliation(s)
- Valeria Y Vasileva
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 Saint-Petersburg, Russia
| | - Zuleikha M Khairullina
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 Saint-Petersburg, Russia
| | - Anastasia V Sudarikova
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 Saint-Petersburg, Russia
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3
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Pavan AR, Dos Santos JL. Advances in Sickle Cell Disease Treatments. Curr Med Chem 2021; 28:2008-2032. [PMID: 32520675 DOI: 10.2174/0929867327666200610175400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/23/2020] [Accepted: 05/07/2020] [Indexed: 11/22/2022]
Abstract
Sickle Cell Disease (SCD) is an inherited disorder of red blood cells that is caused by a single mutation in the β -globin gene. The disease, which afflicts millions of patients worldwide mainly in low income countries, is characterized by high morbidity, mortality and low life expectancy. The new pharmacological and non-pharmacological strategies for SCD is urgent in order to promote treatments able to reduce patient's suffering and improve their quality of life. Since the FDA approval of HU in 1998, there have been few advances in discovering new drugs; however, in the last three years voxelotor, crizanlizumab, and glutamine have been approved as new therapeutic alternatives. In addition, new promising compounds have been described to treat the main SCD symptoms. Herein, focusing on drug discovery, we discuss new strategies to treat SCD that have been carried out in the last ten years to discover new, safe, and effective treatments. Moreover, non-pharmacological approaches, including red blood cell exchange, gene therapy and hematopoietic stem cell transplantation will be presented.
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Affiliation(s)
- Aline Renata Pavan
- Department of Drugs and Medicines, School of Pharmaceutical Sciences, Sao Paulo State University (UNESP), Araraquara, Brazil
| | - Jean Leandro Dos Santos
- Department of Drugs and Medicines, School of Pharmaceutical Sciences, Sao Paulo State University (UNESP), Araraquara, Brazil
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4
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Kast RE, Burns TC, Halatsch ME. Short review of SEC, a potential dexamethasone-sparing regimen for glioblastoma: Spironolactone, ecallantide, clotrimazole. Neurochirurgie 2021; 67:508-515. [PMID: 33450263 DOI: 10.1016/j.neuchi.2020.12.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/31/2020] [Accepted: 12/22/2020] [Indexed: 11/17/2022]
Abstract
This paper presents a short review of data supporting a dexamethasone sparing regimen, SEC, to reduce glioblastoma related brain edema. The conclusion of the reviewed data is that the rationale and risk/benefit ratio favors a pilot study to determine if the three drug regimen of SEC can reduce need for corticosteroid use during the course of glioblastoma. Details of how selected pathophysiological aspects of brain edema occurring during the course of glioblastoma and its treatment intersect with the established action of the three old drugs of SEC indicate that they can be repurposed to reduce that edema. Current first-line treatment of this edema is dexamethasone or related corticosteroids. There are multiple negative prognostic implications of both the edema itself and of dexamethasone, prime among them shortened survival, making a dexamethasone sparing regimen highly desirable. SEC uses spironolactone, an antihypertensive potassium-sparing diuretic acting by mineralocorticoid receptor inhibition, ecallantide acting to inhibit kallikrein activation marketed to treat hereditary angioedema, and clotrimazole, an old antifungal drug that inhibits intermediate conductance Ca++ activated K+ channel (KCa3.1). These three old drugs are well known to most clinicians, have a well-tolerated safety history, and have a robust preclinical database showing their potential to reduce the specific edema of glioblastoma. Additionally, these three drugs were chosen by virtue of each having preclinical evidence of glioblastoma growth and/or migration inhibition independent of their edema reduction action. A clinical study of SEC is being planned.
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Affiliation(s)
- R E Kast
- IIAIGC Study Center, 11, Arlington Ct, VT 05408 Burlington, USA.
| | - T C Burns
- Department of Neurologic Surgery, Mayo Clinic, 200, First St SW, MN 55905 Rochester, USA
| | - M-E Halatsch
- Department of Neurosurgery, Ulm University Hospital, Albert-Einstein-Allée 23, D-89081 Ulm, Germany; Department of Neurosurgery, Cantonal Hospital of Winterthur, Brauerstr, 15, CH-8401, Winterthur, Switzerland
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5
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Li C, Wu D, Li J, Ji X, Qi L, Sun Q, Wang A, Xie C, Gong J, Chen W. Multicomponent crystals of clotrimazole: a combined theoretical and experimental study. CrystEngComm 2021. [DOI: 10.1039/d1ce00934f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Compared with clotrimazole, some multicomponent crystals showed an improvement in solubility and dissolution rate.
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Affiliation(s)
- Chang Li
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Di Wu
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Jiulong Li
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Xu Ji
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Luguang Qi
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Qin Sun
- Shenyang Sinochem Agrochemicals R&D Co., Ltd, Shenyang, Liaoning, 110021 P. R. China
| | - Aiyu Wang
- Shandong Lukang Pharmaceutical Co., Ltd, Jining, Shandong, 272104, P. R. China
| | - Chuang Xie
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, P. R. China
| | - Junbo Gong
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, P. R. China
| | - Wei Chen
- National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, P. R. China
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Jakakul C, Kanjanasirirat P, Muanprasat C. Development of a Cell-Based Assay for Identifying K Ca3.1 Inhibitors Using Intestinal Epithelial Cell Lines. SLAS DISCOVERY 2020; 26:439-449. [PMID: 32830616 DOI: 10.1177/2472555220950661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inhibition of the KCa3.1 potassium channel has therapeutic potential in a variety of human diseases, including inflammation-associated disorders and cancers. However, KCa3.1 inhibitors with high therapeutic promise are currently not available. This study aimed to establish a screening assay for identifying inhibitors of KCa3.1 in native cells and from library compounds derived from natural products in Thailand. The screening platform was successfully developed based on a thallium flux assay in intestinal epithelial (T84) cells with a Z' factor of 0.52. The screening of 1352 compounds and functional validation using electrophysiological analyses identified 8 compounds as novel KCa3.1 inhibitors with IC50 values ranging from 0.14 to 6.57 µM. These results indicate that the assay developed is of excellent quality for high-throughput screening and capable of identifying KCa3.1 inhibitors. This assay may be useful in identifying novel KCa3.1 inhibitors that may have therapeutic potential for inflammation-associated disorders and cancers.
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Affiliation(s)
- Chanon Jakakul
- Section for Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Rajathevi, Bangkok, Thailand
| | - Phongthon Kanjanasirirat
- Excellent Center for Drug Discovery (ECDD), Faculty of Science, Mahidol University, Rajathevi, Bangkok, Thailand
| | - Chatchai Muanprasat
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samutprakarn, Thailand
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7
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Kuck L, Peart JN, Simmonds MJ. Active modulation of human erythrocyte mechanics. Am J Physiol Cell Physiol 2020; 319:C250-C257. [PMID: 32579474 DOI: 10.1152/ajpcell.00210.2020] [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] [Indexed: 12/28/2022]
Abstract
The classic view of the red blood cell (RBC) presents a biologically inert cell that upon maturation has limited capacity to alter its physical properties. This view developed largely because of the absence of translational machinery and inability to synthesize or repair proteins in circulating RBC. Recent developments have challenged this perspective, in light of observations supporting the importance of posttranslational modifications and greater understanding of ion movement in these cells, that each regulate a myriad of cellular properties. There is thus now sufficient evidence to induce a step change in understanding of RBC: rather than passively responding to the surrounding environment, these cells have the capacity to actively regulate their physical properties and thus alter flow behavior of blood. Specific evidence supports that the physical and rheological properties of RBC are subject to active modulation, primarily by the second-messenger molecules nitric oxide (NO) and calcium-ions (Ca2+). Furthermore, an isoform of nitric oxide synthase is expressed in RBC (RBC-NOS), which has been recently demonstrated to have an active role in regulating the physical properties of RBC. Mechanical stimulation of the cell membrane activates RBC-NOS, leading to NO generation, which has several intracellular effects, including the S-nitrosylation of integral membrane components. Intracellular concentration of Ca2+ is increased upon mechanical stimulation via the recently identified mechanosensitive cation channel piezo1. Increased intracellular Ca2+ modifies the physical properties of RBC by regulating cell volume and potentially altering several important intracellular proteins. A synthesis of recent advances in understanding of molecular processes within RBC thus challenges the classic view of these cells and rather indicates a highly active cell with self-regulated mechanical properties.
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Affiliation(s)
- Lennart Kuck
- Biorheology Research Laboratory, Griffith University Gold Coast, Southport, Queensland, Australia
| | - Jason N Peart
- School of Medical Science, Griffith University Gold Coast, Southport, Queensland, Australia
| | - Michael J Simmonds
- Biorheology Research Laboratory, Griffith University Gold Coast, Southport, Queensland, Australia
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Shah F, Dwivedi M. Pathophysiology and recent therapeutic insights of sickle cell disease. Ann Hematol 2020; 99:925-935. [PMID: 32157419 DOI: 10.1007/s00277-020-03977-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 02/25/2020] [Indexed: 02/07/2023]
Abstract
Sickle cell disease (SCD) is an autosomal recessive blood disorder which occurs due to point mutation in the β-globin chain of hemoglobin. Since the past decades, various therapies have been put forth, which are based on obstructing pathophysiological mechanisms of SCD including inhibition of Gardos channel and cation fluxes which in turn prevents sickle erythrocyte destruction and dehydration. The pharmacological approaches are based on the mechanism of reactivating γ-globin expression by utilizing fetal hemoglobin (HbF)-inducing drugs such as hydroxyurea. In SCD, gene therapy could be considered as a promising tool which involves modifying mutation at the gene-specific target by either promoting insertion or deletion of globins. Although there are various therapies emerged so far in the treatment of SCD, many of them have faced a major setback in most of developing countries in terms of cost, unavailability of expertise, and suitable donor. Therefore, in addition to pathophysiological aspects, this review will discuss new advancements and approaches made in the therapeutic domain of SCD including a viewpoint of modulating hemoglobin in SCD by the intervention of probiotics.
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Affiliation(s)
- Firdosh Shah
- C. G. Bhakta Institute of Biotechnology, Faculty of Science, Uka Tarsadia University, Maliba Campus, Gopal Vidyanagar, Bardoli-Mahuva Road, Dist. Surat, Tarsadi, Bardoli, Gujarat, 394350, India
| | - Mitesh Dwivedi
- C. G. Bhakta Institute of Biotechnology, Faculty of Science, Uka Tarsadia University, Maliba Campus, Gopal Vidyanagar, Bardoli-Mahuva Road, Dist. Surat, Tarsadi, Bardoli, Gujarat, 394350, India.
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9
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Abstract
Despite sickle cell disease (SCD) being the most common and severe inherited condition worldwide, therapeutic options are limited. To date, hydroxyurea remains the main treatment option in SCD. However, in the last decade the numbers of interventional clinical trials focussing on therapies for SCD have increased significantly. Many new drugs with various pharmacological targets have emerged and, although the majority have failed to show benefit in clinical trials, some have produced encouraging results. It seems probable that more drugs will soon become available for the treatment of SCD. Furthermore, promising clinical trials with improved outcomes have recently changed the perspective of curative therapies in SCD. Nevertheless, the application of novel therapeutic agents and potential curative treatments will most likely be limited to high-income countries and, thus, will remain unavailable for the majority of people with SCD in the foreseeable future.
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Affiliation(s)
- Amina Nardo-Marino
- Centre for Haemoglobinopathies, Department of Haematology, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark
| | - Valentine Brousse
- Sickle Cell Disease Reference Center, Department of General Pediatrics and Pediatric Infectious Diseases, Necker-Enfants Malades Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - David Rees
- Department of Haematological Medicine, King's College London, King's College Hospital, London, UK
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10
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Roach KM, Bradding P. Ca 2+ signalling in fibroblasts and the therapeutic potential of K Ca3.1 channel blockers in fibrotic diseases. Br J Pharmacol 2020; 177:1003-1024. [PMID: 31758702 DOI: 10.1111/bph.14939] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/23/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022] Open
Abstract
The role of Ca2+ signalling in fibroblasts is of great interest in fibrosis-related diseases. Intracellular free Ca2+ ([Ca2+ ]i ) is a ubiquitous secondary messenger, regulating a number of cellular functions such as secretion, metabolism, differentiation, proliferation and contraction. The intermediate conductance Ca2+ -activated K+ channel KCa 3.1 is pivotal in Ca2+ signalling and plays a central role in fibroblast processes including cell activation, migration and proliferation through the regulation of cell membrane potential. Evidence from a number of approaches demonstrates that KCa 3.1 plays an important role in the development of many fibrotic diseases, including idiopathic pulmonary, renal tubulointerstitial fibrosis and cardiovascular disease. The KCa 3.1 selective blocker senicapoc was well tolerated in clinical trials for sickle cell disease, raising the possibility of rapid translation to the clinic for people suffering from pathological fibrosis. This review after analysing all the data, concludes that targeting KCa 3.1 should be a high priority for human fibrotic disease.
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Affiliation(s)
- Katy M Roach
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Peter Bradding
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, Leicester, UK
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11
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K Ca3.1 Channels Confer Radioresistance to Breast Cancer Cells. Cancers (Basel) 2019; 11:cancers11091285. [PMID: 31480522 PMCID: PMC6770875 DOI: 10.3390/cancers11091285] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/09/2019] [Accepted: 08/21/2019] [Indexed: 12/14/2022] Open
Abstract
KCa3.1 K+ channels reportedly contribute to the proliferation of breast tumor cells and may serve pro-tumor functions in the microenvironment. The putative interaction of KCa3.1 with major anti-cancer treatment strategies, which are based on cytotoxic drugs or radiotherapy, remains largely unexplored. We employed KCa3.1-proficient and -deficient breast cancer cells derived from breast cancer-prone MMTV-PyMT mice, pharmacological KCa3.1 inhibition, and a syngeneic orthotopic mouse model to study the relevance of functional KCa3.1 for therapy response. The KCa3.1 status of MMTV-PyMT cells did not determine tumor cell proliferation after treatment with different concentrations of docetaxel, doxorubicin, 5-fluorouracil, or cyclophosphamide. KCa3.1 activation by ionizing radiation (IR) in breast tumor cells in vitro, however, enhanced radioresistance, probably via an involvement of the channel in IR-stimulated Ca2+ signals and DNA repair pathways. Consistently, KCa3.1 knockout increased survival time of wildtype mice upon syngeneic orthotopic transplantation of MMTV-PyMT tumors followed by fractionated radiotherapy. Combined, our results imply that KCa3.1 confers resistance to radio- but not to chemotherapy in the MMTV-PyMT breast cancer model. Since KCa3.1 is druggable, KCa3.1 targeting concomitant to radiotherapy seems to be a promising strategy to radiosensitize breast tumors.
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12
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Jin LW, Lucente JD, Nguyen HM, Singh V, Singh L, Chavez M, Bushong T, Wulff H, Maezawa I. Repurposing the KCa3.1 inhibitor senicapoc for Alzheimer's disease. Ann Clin Transl Neurol 2019; 6:723-738. [PMID: 31019997 PMCID: PMC6469250 DOI: 10.1002/acn3.754] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/06/2019] [Accepted: 02/10/2019] [Indexed: 01/01/2023] Open
Abstract
Objective Microglia play a pivotal role in the initiation and progression of Alzheimer's disease (AD). We here tested the therapeutic hypothesis that the Ca2+‐activated potassium channel KCa3.1 constitutes a potential target for treating AD by reducing neuroinflammation. Methods To determine if KCa3.1 is relevant to AD, we tested if treating cultured microglia or hippocampal slices with Aβ oligomer (AβO) activated KCa3.1 in microglia, and if microglial KCa3.1 was upregulated in 5xFAD mice and in human AD brains. The expression/activity of KCa3.1 was examined by qPCR, Western blotting, immunohistochemistry, and whole‐cell patch‐clamp. To investigate the role of KCa3.1 in AD pathology, we resynthesized senicapoc, a clinically tested KCa3.1 blocker, and determined its pharmacokinetic properties and its effect on microglial activation, Aβ deposition and hippocampal long‐term potentiation (hLTP) in 5xFAD mice. Results We found markedly enhanced microglial KCa3.1 expression/activity in brains of both 5xFAD mice and AD patients. In hippocampal slices, microglial KCa3.1 expression/activity was increased by AβO treatment, and its inhibition diminished the proinflammatory and hLTP‐impairing activities of AβO. Senicapoc exhibited excellent brain penetrance and oral availability, and in 5xFAD mice, reduced neuroinflammation, decreased cerebral amyloid load, and enhanced hippocampal neuronal plasticity. Interpretation Our results prompt us to propose repurposing senicapoc for AD clinical trials, as senicapoc has excellent pharmacological properties and was safe and well‐tolerated in a prior phase‐3 clinical trial for sickle cell anemia. Such repurposing has the potential to expedite the urgently needed new drug discovery for AD.
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Affiliation(s)
- Lee-Way Jin
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
| | - Jacopo Di Lucente
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
| | - Hai M Nguyen
- Department of Pharmacology University of California Davis Davis California
| | - Vikrant Singh
- Department of Pharmacology University of California Davis Davis California
| | - Latika Singh
- Department of Pharmacology University of California Davis Davis California
| | - Monique Chavez
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
| | - Trevor Bushong
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
| | - Heike Wulff
- Department of Pharmacology University of California Davis Davis California
| | - Izumi Maezawa
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
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13
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Duan T, Cil O, Thiagarajah JR, Verkman AS. Intestinal epithelial potassium channels and CFTR chloride channels activated in ErbB tyrosine kinase inhibitor diarrhea. JCI Insight 2019; 4:126444. [PMID: 30668547 PMCID: PMC6478423 DOI: 10.1172/jci.insight.126444] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 01/14/2019] [Indexed: 12/11/2022] Open
Abstract
Diarrhea is a major side effect of ErbB receptor tyrosine kinase inhibitors (TKIs) in cancer chemotherapy. Here, we show that the primary mechanism of ErbB TKI diarrhea is activation of basolateral membrane potassium (K+) channels and apical membrane chloride (Cl-) channels in intestinal epithelia and demonstrate the efficacy of channel blockers in a rat model of TKI diarrhea. Short-circuit current in colonic epithelial cells showed that the TKIs gefitinib, lapatinib, and afatinib do not affect basal secretion but amplify carbachol-stimulated secretion by 2- to 3-fold. Mechanistic studies with the second-generation TKI afatinib showed that the amplifying effect on Cl- secretion was Ca2+ and cAMP independent, was blocked by CF transmembrane conductance regulator (CFTR) and K+ channel inhibitors, and involved EGFR binding and ERK signaling. Afatinib-amplified activation of basolateral K+ and apical Cl- channels was demonstrated by selective membrane permeabilization, ion substitution, and channel inhibitors. Rats that were administered afatinib orally at 60 mg/kg/day developed diarrhea with increased stool water from approximately 60% to greater than 80%, which was reduced by up to 75% by the K+ channel inhibitors clotrimazole or senicapoc or the CFTR inhibitor (R)-BPO-27. These results indicate a mechanism for TKI diarrhea involving K+ and Cl- channel activation and support the therapeutic efficacy of channel inhibitors.
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Affiliation(s)
- Tianying Duan
- Departments of Medicine and Physiology, UCSF, San Francisco, California, USA.,Department of Gastroenterology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Onur Cil
- Departments of Medicine and Physiology, UCSF, San Francisco, California, USA.,Department of Pediatrics, UCSF, San Francisco, California, USA
| | - Jay R Thiagarajah
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Alan S Verkman
- Departments of Medicine and Physiology, UCSF, San Francisco, California, USA
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14
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Telen MJ, Malik P, Vercellotti GM. Therapeutic strategies for sickle cell disease: towards a multi-agent approach. Nat Rev Drug Discov 2019; 18:139-158. [PMID: 30514970 PMCID: PMC6645400 DOI: 10.1038/s41573-018-0003-2] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
For over 100 years, clinicians and scientists have been unravelling the consequences of the A to T substitution in the β-globin gene that produces haemoglobin S, which leads to the systemic manifestations of sickle cell disease (SCD), including vaso-occlusion, anaemia, haemolysis, organ injury and pain. However, despite growing understanding of the mechanisms of haemoglobin S polymerization and its effects on red blood cells, only two therapies for SCD - hydroxyurea and L-glutamine - are approved by the US Food and Drug Administration. Moreover, these treatment options do not fully address the manifestations of SCD, which arise from a complex network of interdependent pathophysiological processes. In this article, we review efforts to develop new drugs targeting these processes, including agents that reactivate fetal haemoglobin, anti-sickling agents, anti-adhesion agents, modulators of ischaemia-reperfusion and oxidative stress, agents that counteract free haemoglobin and haem, anti-inflammatory agents, anti-thrombotic agents and anti-platelet agents. We also discuss gene therapy, which holds promise of a cure, although its widespread application is currently limited by technical challenges and the expense of treatment. We thus propose that developing systems-oriented multi-agent strategies on the basis of SCD pathophysiology is needed to improve the quality of life and survival of people with SCD.
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Affiliation(s)
- Marilyn J Telen
- Division of Hematology, Department of Medicine and Duke Comprehensive Sickle Cell Center, Duke University, Durham, NC, USA.
| | - Punam Malik
- Division of Experimental Hematology and Cancer Biology and the Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Gregory M Vercellotti
- Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
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15
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Soriano-Ruiz JL, Suñer-Carbó J, Calpena-Campmany AC, Bozal-de Febrer N, Halbaut-Bellowa L, Boix-Montañés A, Souto EB, Clares-Naveros B. Clotrimazole multiple W/O/W emulsion as anticandidal agent: Characterization and evaluation on skin and mucosae. Colloids Surf B Biointerfaces 2018; 175:166-174. [PMID: 30530002 DOI: 10.1016/j.colsurfb.2018.11.070] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/11/2018] [Accepted: 11/27/2018] [Indexed: 01/09/2023]
Abstract
Clotrimazole (CLT) was formulated in a multiple W/O/W emulsion (ME) with the aim of evaluating its potential as topical anticandidal agent and comparing with marketed products. A previously evaluated CLT-ME was selected and physicochemically characterized. The in vitro release behavior and the ex vivo permeation profiles were assessed using Franz diffusion cells using three different types of biological membranes: human skin and porcine buccal, sublingual and vaginal mucosae. The antifungal activity against Candida strains was also tested. Results showed CLT-MEs sizes of 29.206 and 47.678 μm with skin compatible pH values of 6.47 and 6.42 exhibiting high zeta potential values of -55.13 and -55.59 mV with dependence on the pH variation. The physicochemical stability was kept for a period of 180 days of storage at room temperature. CLT-MEs exhibited pseudoplastic behavior with hysteresis areas and viscosities of 286 and 331 mPa⋅s showing higher spreadability properties than commercial counterparts. An improved CLT release pattern was supplied by the ME system following a hyperbolic model. Likewise, ME system gave higher skin permeation flux of CLT than commercial reference. CLT amounts retained in the skin and mucosae were also higher than commercial references, which coupled with the higher antimycotic efficacy make CLT-MEs a great tool for clinical investigation of topical candidiasis treatments.
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Affiliation(s)
- José L Soriano-Ruiz
- Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Granada, University Campus of Cartuja, 18071 Granada, Spain
| | - Joaquim Suñer-Carbó
- Department of Pharmacy and Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain
| | - Ana C Calpena-Campmany
- Department of Pharmacy and Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain; Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, 645 Diagonal Ave., 08028 Barcelona, Spain
| | - Nuria Bozal-de Febrer
- Department of Biology, Healthcare and the Environment, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain
| | - Lyda Halbaut-Bellowa
- Department of Pharmacy and Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain; Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, 645 Diagonal Ave., 08028 Barcelona, Spain
| | - Antonio Boix-Montañés
- Department of Pharmacy and Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain
| | - Eliana B Souto
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Polo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal; CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar 4710-057 Braga, Portugal
| | - Beatriz Clares-Naveros
- Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Granada, University Campus of Cartuja, 18071 Granada, Spain; Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, 645 Diagonal Ave., 08028 Barcelona, Spain.
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16
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Soriano-Ruiz JL, Calpena-Capmany AC, Cañadas-Enrich C, Febrer NBD, Suñer-Carbó J, Souto EB, Clares-Naveros B. Biopharmaceutical profile of a clotrimazole nanoemulsion: Evaluation on skin and mucosae as anticandidal agent. Int J Pharm 2018; 554:105-115. [PMID: 30395953 DOI: 10.1016/j.ijpharm.2018.11.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 10/30/2018] [Accepted: 11/01/2018] [Indexed: 12/15/2022]
Abstract
Clotrimazole (CLT) was formulated in a nanoemulsion (NE) for the topical treatment of candidiasis consisting of 10% labrafac® lipophile, 60% labrasol®:capryol® 90 mixture (ratio 4:1) and 30% propylene glycol. Physicochemical properties, stability, rheology, in vitro drug release, ex vivo drug permeation through human skin and porcine buccal, sublingual and vaginal mucosae, antifungal efficacy, as well as in vivo skin tolerance were evaluated. 1% CLT-NE (CLT-NE1) and 2% CLT-NE (CLT-NE2) exhibited 153 ± 17.25 and 186 ± 15.38 nm droplet sizes, low polydispersity indexes, negative zeta potentials and biocompatible pH values. The CLT-NEs exhibited typical Newtonian profiles with viscosities of 42.14 ± 0.037 mPa·s and 41.35 ± 0.041 mPa·s, respectively and higher extensibility properties than commercial counterparts retaining their physicochemical properties for 180 days. NEs provided a sustained release of drug according to the first order model. Similar skin permeation properties were observed between CLT-NE1 and commercial reference. However, significant higher CLT amounts retained in mucosae were provided by CLT-NE2 when compared with references. Antifungal efficacies were also higher than commercial references, and the in vivo tolerance study confirmed the suitability for topical application, making CLT-NEs a great tool for clinical investigation of topical candidiasis treatments.
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Affiliation(s)
- José L Soriano-Ruiz
- Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Granada, University Campus of Cartuja, 18071 Granada, Spain
| | - Ana C Calpena-Capmany
- Department of Pharmacy and Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain; Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, 645 Diagonal Ave., 08028 Barcelona, Spain
| | - Cristina Cañadas-Enrich
- Department of Pharmacy and Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain
| | - Nuria Bozal-de Febrer
- Department of Biology, Healthcare and the Environment, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain
| | - Joaquim Suñer-Carbó
- Department of Pharmacy and Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 27-31 Joan XXIII Ave., 08028 Barcelona, Spain
| | - Eliana B Souto
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra, Polo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Beatriz Clares-Naveros
- Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Granada, University Campus of Cartuja, 18071 Granada, Spain; Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, 645 Diagonal Ave., 08028 Barcelona, Spain.
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17
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Nagalla S, Ballas SK. Drugs for preventing red blood cell dehydration in people with sickle cell disease. Cochrane Database Syst Rev 2018; 10:CD003426. [PMID: 30338520 PMCID: PMC6517013 DOI: 10.1002/14651858.cd003426.pub6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. This is an updated version of a previously published review. OBJECTIVES To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register. We also searched online trials registries for any ongoing trials (01 July 2018).Last search of the Group's Haemoglobinopathies Trials Register: 08 October 2018. SELECTION CRITERIA Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both authors independently selected studies for inclusion, assessed study quality and extracted data. MAIN RESULTS Of the 51 studies identified, three met the inclusion criteria, including 524 people with sickle cell disease aged between 12 and 65 years of age. One study tested the effectiveness of zinc sulphate as compared to placebo and the remaining two assessed senicapoc versus placebo. No deaths were seen in any of the studies (low-quality evidence). The zinc sulphate study showed a significant reduction in painful crises (in a total of 145 participants) over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15) (moderate-quality evidence). However, analysis was restricted due to limited statistical data. Changes to red blood cell parameters and blood counts were inconsistent (very low-quality evidence). No serious adverse events were noted in the study. The Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo showed that the high dose senicapoc showed significant improvement in change in hemoglobin level, the number and proportion of dense red blood cells, red blood cell count and indices and hematocrit value (very low-quality evidence). The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups (low-quality evidence). A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises. AUTHORS' CONCLUSIONS While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red blood cell survival (depending on dose), this did not lead to fewer painful crises.Given this is no longer an active area of research, this review will no longer be regularly updated.
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Affiliation(s)
- Srikanth Nagalla
- Division of Hematology and Oncology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas, USA, 75390
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18
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Brown BM, Pressley B, Wulff H. KCa3.1 Channel Modulators as Potential Therapeutic Compounds for Glioblastoma. Curr Neuropharmacol 2018; 16:618-626. [PMID: 28676010 PMCID: PMC5997873 DOI: 10.2174/1570159x15666170630164226] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/31/2022] Open
Abstract
Background The intermediate-conductance Ca2+-activated K+ channel KCa3.1 is widely expressed in cells of the immune system such as T- and B-lymphocytes, mast cells, macrophages and microglia, but also found in dedifferentiated vascular smooth muscle cells, fibroblasts and many cancer cells including pancreatic, prostate, leukemia and glioblastoma. In all these cell types KCa3.1 plays an important role in cellular activation, migration and proliferation by regulating membrane potential and Ca2+ signaling. Methods and Results KCa3.1 therefore constitutes an attractive therapeutic target for diseases involving excessive proliferation or activation of one more of these cell types and researchers both in academia and in the pharmaceutical industry have developed several potent and selective small molecule inhibitors of KCa3.1. This article will briefly review the available compounds (TRAM-34, senicapoc, NS6180), their binding sites and mechanisms of action, and then discuss the potential usefulness of these compounds for the treatment of brain tumors based on their brain penetration and their efficacy in reducing microglia activation in animal models of ischemic stroke and Alzheimer’s disease. Conclusion Senicapoc, which has previously been in Phase III clinical trials, would be available for repurposing, and could be used to quickly translate findings made with other KCa3.1 blocking tool compounds into clinical trials.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
| | - Brandon Pressley
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
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19
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Sidorenko SV, Ziganshin RH, Luneva OG, Deev LI, Alekseeva NV, Maksimov GV, Grygorczyk R, Orlov SN. Proteomics-based identification of hypoxia-sensitive membrane-bound proteins in rat erythrocytes. J Proteomics 2018; 184:25-33. [DOI: 10.1016/j.jprot.2018.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/01/2018] [Accepted: 06/11/2018] [Indexed: 12/25/2022]
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20
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Abstract
Cell dehydration is a distinguishing characteristic of sickle cell disease and an important contributor to disease pathophysiology. Due to the unique dependence of Hb S polymerization on cellular Hb S concentration, cell dehydration promotes polymerization and sickling. In double heterozygosis for Hb S and C (SC disease) dehydration is the determining factor in disease pathophysiology. Three major ion transport pathways are involved in sickle cell dehydration: the K-Cl cotransport (KCC), the Gardos channel (KCNN4) and Psickle, the polymerization induced membrane permeability, most likely mediated by the mechano-sensitive ion channel PIEZO1. Each of these pathways exhibit unique characteristics in regulation by oxygen tension, intracellular and extracellular environment, and functional expression in reticulocytes and mature red cells. The unique dependence of K-Cl cotransport on intracellular Mg and the abnormal reduction of erythrocyte Mg content in SS and SC cells had led to clinical studies assessing the effect of oral Mg supplementation. Inhibition of Gardos channel by clotrimazole and senicapoc has led to Phase 1,2,3 trials in patients with sickle cell disease. While none of these studies has resulted in the approval of a novel therapy for SS disease, they have highlighted the key role played by these pathways in disease pathophysiology.
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Affiliation(s)
- Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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21
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Grygorczyk R, Orlov SN. Effects of Hypoxia on Erythrocyte Membrane Properties-Implications for Intravascular Hemolysis and Purinergic Control of Blood Flow. Front Physiol 2017; 8:1110. [PMID: 29312010 PMCID: PMC5744585 DOI: 10.3389/fphys.2017.01110] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/14/2017] [Indexed: 01/08/2023] Open
Abstract
Intravascular hemolysis occurs in hereditary, acquired, and iatrogenic hemolytic conditions but it could be also a normal physiological process contributing to intercellular signaling. New evidence suggests that intravascular hemolysis and the associated release of adenosine triphosphate (ATP) may be an important mechanism for in vivo local purinergic signaling and blood flow regulation during exercise and hypoxia. However, the mechanisms that modulate hypoxia-induced RBC membrane fragility remain unclear. Here, we provide an overview of the role of RBC ATP release in the regulation of vascular tone and prevailing assumptions on the putative release mechanisms. We show importance of intravascular hemolysis as a source of ATP for local purinergic regulation of blood flow and discuss processes that regulate membrane propensity to rupture under stress and hypoxia.
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Affiliation(s)
| | - Sergei N. Orlov
- Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
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22
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Wajih N, Basu S, Jailwala A, Kim HW, Ostrowski D, Perlegas A, Bolden CA, Buechler NL, Gladwin MT, Caudell DL, Rahbar E, Alexander-Miller MA, Vachharajani V, Kim-Shapiro DB. Potential therapeutic action of nitrite in sickle cell disease. Redox Biol 2017; 12:1026-1039. [PMID: 28511346 PMCID: PMC5430577 DOI: 10.1016/j.redox.2017.05.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/07/2017] [Accepted: 05/08/2017] [Indexed: 12/26/2022] Open
Abstract
Sickle cell disease is caused by a mutant form of hemoglobin that polymerizes under hypoxic conditions, increasing rigidity, fragility, calcium influx-mediated dehydration, and adhesivity of red blood cells. Increased red cell fragility results in hemolysis, which reduces nitric oxide (NO) bioavailability, and induces platelet activation and inflammation leading to adhesion of circulating blood cells. Nitric Oxide inhibits adhesion and platelet activation. Nitrite has emerged as an attractive therapeutic agent that targets delivery of NO activity to areas of hypoxia through bioactivation by deoxygenated red blood cell hemoglobin. In this study, we demonstrate anti-platelet activity of nitrite at doses achievable through dietary interventions with comparison to similar doses with other NO donating agents. Unlike other NO donating agents, nitrite activity is shown to be potentiated in the presence of red blood cells in hypoxic conditions. We also show that nitrite reduces calcium associated loss of phospholipid asymmetry that is associated with increased red cell adhesion, and that red cell deformability is also improved. We show that nitrite inhibits red cell adhesion in a microfluidic flow-channel assay after endothelial cell activation. In further investigations, we show that leukocyte and platelet adhesion is blunted in nitrite-fed wild type mice compared to control after either lipopolysaccharide- or hemolysis-induced inflammation. Moreover, we demonstrate that nitrite treatment results in a reduction in adhesion of circulating blood cells and reduced red blood cell hemolysis in humanized transgenic sickle cell mice subjected to local hypoxia. These data suggest that nitrite is an effective anti-platelet and anti-adhesion agent that is activated by red blood cells, with enhanced potency under physiological hypoxia and in venous blood that may be useful therapeutically.
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Affiliation(s)
- Nadeem Wajih
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States; Translational Science Center, Wake Forest University, Winston-Salem, NC 27109, United States
| | - Swati Basu
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States; Translational Science Center, Wake Forest University, Winston-Salem, NC 27109, United States
| | - Anuj Jailwala
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States
| | - Hee Won Kim
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States
| | - David Ostrowski
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States
| | - Andreas Perlegas
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States
| | - Crystal A Bolden
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States
| | - Nancy L Buechler
- Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, United States
| | - Mark T Gladwin
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, United States; Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - David L Caudell
- Department of Pathology-Comparative Medicine, Section on Rheumatology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, United States
| | - Elaheh Rahbar
- Department of Biomedical Engineering, Section on Rheumatology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, United States
| | - Martha A Alexander-Miller
- Department of Microbiology and Immunology, Section on Rheumatology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, United States
| | - Vidula Vachharajani
- Translational Science Center, Wake Forest University, Winston-Salem, NC 27109, United States; Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, United States.
| | - Daniel B Kim-Shapiro
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States; Translational Science Center, Wake Forest University, Winston-Salem, NC 27109, United States.
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23
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Suñer J, Calpena AC, Clares B, Cañadas C, Halbaut L. Development of Clotrimazole Multiple W/O/W Emulsions as Vehicles for Drug Delivery: Effects of Additives on Emulsion Stability. AAPS PharmSciTech 2017; 18:539-550. [PMID: 27126008 DOI: 10.1208/s12249-016-0529-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 04/05/2016] [Indexed: 11/30/2022] Open
Abstract
Multiple emulsions have attracted considerable attention in recent years for application as potential delivery systems for different drugs. The aim of the present work is to design a new formulation containing clotrimazole (CLT) loaded into multiple emulsions by two-step emulsification method for transdermal delivery. Different ingredients and quantities like primary and secondary co-emulsifiers and the nature of oily phase were assayed in order to optimize the best system for good. Resulting formulations were characterized in terms of droplet size, conductivity, pH, entrapment efficiency, rheological behavior, and stability under various storage conditions for 180 days. pH values of multiple emulsions containing CLT ranged from 7.04 ± 0.03 to 6.23 ± 0.04. Droplet size increased when increasing concentration of sorbitan stearate. The addition of polysorbate 80 resulted in significant decrease of oil droplet size comparing with those prepared without this. CLT entrapment efficiency ranged between 85.64% and 97.47%. All formulations exhibited non-Newtonian pseudoplastic flow with some apparent thixotropic behavior. Cross and Herschel-Bulkley equations were the models that best fitted experimental data. In general, the addition of 1% polysorbate 80 resulted in a decrease of viscosity values. No signals of optical instability were observed, and physicochemical properties remained almost constant when samples were stored at room temperature after 180 days. On the contrary, samples stored at 40°C exhibited pronounced increase in conductivity values 24 h after elaboration and some of them were unstable after 180 days of storage. JMLP01 was proposed as an innovative and stable system to incorporate CLT as active pharmaceutical ingredient.
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Nagalla S, Ballas SK. Drugs for preventing red blood cell dehydration in people with sickle cell disease. Cochrane Database Syst Rev 2016; 3:CD003426. [PMID: 26942338 DOI: 10.1002/14651858.cd003426.pub5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. This is an updated version of a previously published review. OBJECTIVES To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 28 November 2015. SELECTION CRITERIA Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both authors independently selected studies for inclusion, assessed study quality and extracted data. MAIN RESULTS Of the 51 studies identified, three met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises. AUTHORS' CONCLUSIONS While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red cell survival (depending on dose), this did not lead to fewer painful crises.We will continue to run searches to identify any potentially relevant trials; however, we do not plan to update other sections of the review until new trials are published.
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Affiliation(s)
- Srikanth Nagalla
- Department of Medicine, Division of Hematology, Thomas Jefferson University, Medical Center Boulevard, 1015 Walnut Street, Philadelphia, Pennsylvania, USA, PA 19107-5099
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25
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Ombrone D, Giocaliere E, Forni G, Malvagia S, la Marca G. Expanded newborn screening by mass spectrometry: New tests, future perspectives. MASS SPECTROMETRY REVIEWS 2016; 35:71-84. [PMID: 25952022 DOI: 10.1002/mas.21463] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 01/09/2015] [Indexed: 05/02/2023]
Abstract
Tandem mass spectrometry (MS/MS) has become a leading technology used in clinical chemistry and has shown to be particularly sensitive and specific when used in newborn screening (NBS) tests. The success of tandem mass spectrometry is due to important advances in hardware, software and clinical applications during the last 25 years. MS/MS permits a very rapid measurement of many metabolites in different biological specimens by using filter paper spots or directly on biological fluids. Its use in NBS give us the chance to identify possible treatable metabolic disorders even when asymptomatic and the benefits gained by this type of screening is now recognized worldwide. Today the use of MS/MS for second-tier tests and confirmatory testing is promising especially in the early detection of new disorders such as some lysosomal storage disorders, ADA and PNP SCIDs, X-adrenoleucodistrophy (X-ALD), Wilson disease, guanidinoacetate methyltransferase deficiency (GAMT), and Duchenne muscular dystrophy. The new challenge for the future will be reducing the false positive rate by using second-tier tests, avoiding false negative results by using new specific biomarkers and introducing new treatable disorders in NBS programs.
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Affiliation(s)
- Daniela Ombrone
- Newborn screening, Clinical Chemistry and Pharmacology Lab, Meyer Children's University Hospital, Viale Pieraccini 24, Florence, 50139, Italy
- Department of Neurosciences, Psychology, Drug Research and Child Health, University of Florence, Viale Pieraccini 6, Florence, 50139, Italy
| | - Elisa Giocaliere
- Newborn screening, Clinical Chemistry and Pharmacology Lab, Meyer Children's University Hospital, Viale Pieraccini 24, Florence, 50139, Italy
| | - Giulia Forni
- Newborn screening, Clinical Chemistry and Pharmacology Lab, Meyer Children's University Hospital, Viale Pieraccini 24, Florence, 50139, Italy
| | - Sabrina Malvagia
- Newborn screening, Clinical Chemistry and Pharmacology Lab, Meyer Children's University Hospital, Viale Pieraccini 24, Florence, 50139, Italy
| | - Giancarlo la Marca
- Newborn screening, Clinical Chemistry and Pharmacology Lab, Meyer Children's University Hospital, Viale Pieraccini 24, Florence, 50139, Italy
- Department of Neurosciences, Psychology, Drug Research and Child Health, University of Florence, Viale Pieraccini 6, Florence, 50139, Italy
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26
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Hannemann A, Rees D, Tewari S, Gibson J. Cation Homeostasis in Red Cells From Patients With Sickle Cell Disease Heterologous for HbS and HbC (HbSC Genotype). EBioMedicine 2015; 2:1669-76. [PMID: 26870793 PMCID: PMC4740305 DOI: 10.1016/j.ebiom.2015.09.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/07/2015] [Accepted: 09/15/2015] [Indexed: 11/24/2022] Open
Abstract
Sickle cell disease (SCD) in patients of HbSC genotype is considered similar, albeit milder, to that in homozygous HbSS individuals--but with little justification. In SCD, elevated red cell cation permeability is critical as increased solute loss causes dehydration and encourages sickling. Recently, we showed that the KCl cotransporter (KCC) activity in red cells from HbSC patients correlated significantly with disease severity, but that in HbSS patients did not. Two transporters involved in red cell dehydration, the conductive channels Psickle and the Gardos channel, behaved similarly in red cells from the two genotypes, but were significantly less active in HbSC patients. By contrast, KCC activity was quantitatively greater in HbSC red cells. Results suggest that KCC is likely to have greater involvement in red cell dehydration in HbSC patients, which could explain its association with disease severity in this genotype. This work supports the hypothesis that SCD in HbSC patients is a distinct disease entity to that in HbSS patients. Results suggest the possibility of designing specific treatments of particular benefit to HbSC patients and a rationale for the development of prognostic markers, to inform early treatment of children likely to develop more severe complications of the disease.
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Affiliation(s)
- A. Hannemann
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - D.C. Rees
- Department of Paediatric Haematology, King's College London School of Medicine, King's College Hospital NHS Foundation Trust, Denmark Hill, London SE5 9RS, UK
| | - S. Tewari
- Department of Paediatric Haematology, King's College London School of Medicine, King's College Hospital NHS Foundation Trust, Denmark Hill, London SE5 9RS, UK
| | - J.S. Gibson
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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Heidari N, Halvaji F, Rezaei Mofrad P, Jalali Far MA, Jalali MT, Zare Javid A. In Vitro Impact of Treatment With Aqueous Extract of Cassia Fistula on Red Blood Cell Sickling in Individuals With Sickle Cell Trait. Jundishapur J Nat Pharm Prod 2015. [DOI: 10.17795/jjnpp-17261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Archer N, Galacteros F, Brugnara C. 2015 Clinical trials update in sickle cell anemia. Am J Hematol 2015; 90:934-50. [PMID: 26178236 PMCID: PMC5752136 DOI: 10.1002/ajh.24116] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 07/08/2015] [Indexed: 02/02/2023]
Abstract
Polymerization of HbS and cell sickling are the prime pathophysiological events in sickle cell disease (SCD). Over the last 30 years, a substantial understanding at the molecular level has been acquired on how a single amino acid change in the structure of the beta chain of hemoglobin leads to the explosive growth of the HbS polymer and the associated changes in red cell morphology. O2 tension and intracellular HbS concentration are the primary molecular drivers of this process, and are obvious targets for developing new therapies. However, polymerization and sickling are driving a complex network of associated cellular changes inside and outside of the erythrocyte, which become essential components of the inflammatory vasculopathy and result in a large range of potential acute and chronic organ damages. In these areas, a multitude of new targets for therapeutic developments have emerged, with several ongoing or planned new therapeutic interventions. This review outlines the key points of SCD pathophysiology as they relate to the development of new therapies, both at the pre-clinical and clinical levels.
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Affiliation(s)
- Natasha Archer
- Pediatric Hematology/Oncology Dana-Farber/Children’s Hospital Blood Disorders and Cancer Center, Boston, Massachusetts
| | - Frédéric Galacteros
- Centre De Référence Des Syndromes Drépanocytaires Majeurs, Hôpital Henri-Mondor, APHP, UPEC, Creteil, France
| | - Carlo Brugnara
- Department of Laboratory Medicine, Boston Children’s Hospital, Harvard Medical School Boston, Massachusetts
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Electrophysiological Studies into the Safety of the Anti-diarrheal Drug Clotrimazole during Oral Rehydration Therapy. PLoS Negl Trop Dis 2015; 9:e0004098. [PMID: 26405813 PMCID: PMC4583490 DOI: 10.1371/journal.pntd.0004098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/30/2015] [Indexed: 11/19/2022] Open
Abstract
Background and Aims Morbidity and mortality from acute diarrheal disease remains high, particularly in developing countries and in cases of natural or man-made disasters. Previous work has shown that the small molecule clotrimazole inhibits intestinal Cl- secretion by blocking both cyclic nucleotide- and Ca2+-gated K+ channels, implicating its use in the treatment of diarrhea of diverse etiologies. Clotrimazole, however, might also inhibit transporters that mediate the inwardly directed electrochemical potential for Na+-dependent solute absorption, which would undermine its clinical application. Here we test this possibility by examining the effects of clotrimazole on Na+-coupled glucose uptake. Materials and Methods Short-circuit currents (Isc) following administration of glucose and secretagogues were studied in clotrimazole-treated jejunal sections of mouse intestine mounted in Ussing chambers. Results Treatment of small intestinal tissue with clotrimazole inhibited the Cl- secretory currents that resulted from challenge with the cAMP-agonist vasoactive intestinal peptide (VIP) or Ca2+-agonist carbachol in a dose-dependent fashion. A dose of 30 μM was effective in significantly reducing the Isc response to VIP and carbachol by 50% and 72%, respectively. At this dose, uptake of glucose was only marginally affected (decreased by 14%, p = 0.37). There was no measurable effect on SGLT1-mediated sugar transport, as uptake of SGLT1-restricted 3-O-methyl glucose was equivalent between clotrimazole-treated and untreated tissue (98% vs. 100%, p = 0.90). Conclusion Treatment of intestinal tissue with clotrimazole significantly reduced secretory responses caused by both cAMP- and Ca2+-dependent agonists as expected, but did not affect Na+-coupled glucose absorption. Clotrimazole could thus be used in conjunction with oral rehydration solution as a low-cost, auxiliary treatment of acute secretory diarrheas. In acute infectious diarrhea, the active secretion of Cl- ions contributes to the secondary loss of Na+ and water from the intestine. Apical Cl- secretion from intestinal epithelial cells is dependent upon cyclic nucleotide- and Ca2+-dependent intracellular signals and requires the concomitant transport of K+ through basolateral K+ channels for maintenance of an electroneutral state. Hence, when efflux of K+ in enterocytes is blocked, Cl- secretion necessarily shuts down. The FDA-approved antifungal drug clotrimazole has been demonstrated to be a potent blocker of basolateral cAMP- and Ca2+-gated K+ channels in enterocytes, and therefore likely has therapeutic efficacy for secretory diarrheas. One important concern that could compromise its clinical applicability as a novel anti-diarrheal drug, however, is that clotrimazole might affect intestinal Na+-coupled glucose absorption, which constitutes the physiological basis of oral rehydration therapies and is thus critical for the efficacy of the current golden standard treatment for acute infectious diarrheal diseases. In this work, we demonstrate that clotrimazole effectively blocks Cl- secretion in mouse intestine after stimulation with secretory stimuli, without affecting the capacity to take up Na+ and glucose. These results pave the way towards further clinical development of clotrimazole as a new pharmacologic strategy for acute diarrheal disease.
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Low-dose photon irradiation alters cell differentiation via activation of hIK channels. Pflugers Arch 2014; 467:1835-49. [PMID: 25277267 DOI: 10.1007/s00424-014-1601-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 08/20/2014] [Accepted: 08/22/2014] [Indexed: 10/24/2022]
Abstract
To understand the impact of ionizing irradiation from diagnostics and radiotherapy on cells, we examined K(+) channel activity before and immediately after exposing cells to X-rays. Already, low dose in the cGy range caused in adenocarcinoma A549 cells within minutes a hyperpolarization following activation of the human intermediate-conductance Ca(2+)-activated K(+) channel (hIK). The response was specific for cells, which functionally expressed hIK channels and in which hIK activity was low before irradiation. HEK293 cells, which do not respond to X-ray irradiation, accordingly develop a sensitivity to this stress after heterologous expression of hIK channels. The data suggest that hIK activation involves a Ca(2+)-mediated signaling cascade because channel activation is suppressed by a strong cytosolic Ca(2+) buffer. The finding that an elevation of H2O2 causes an increase in the concentration of cytosolic Ca(2+) suggests that radicals, which emerge early in response to irradiation, trigger this Ca(2+) signaling cascade. Inhibition of hIK channels by specific blockers clotrimazole and TRAM-34 slowed cell proliferation and migration in "wound" scratch assays; ionizing irradiation, in turn, stimulated the latter process presumably via its activation of the hIK channels. These data stress an indirect radiosensitivity of hIK channels with an impact on cell differentiation.
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Crowley PD, Gallagher HC. Clotrimazole as a pharmaceutical: past, present and future. J Appl Microbiol 2014; 117:611-7. [PMID: 24863842 DOI: 10.1111/jam.12554] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 04/29/2014] [Accepted: 05/21/2014] [Indexed: 11/29/2022]
Abstract
Clotrimazole is a broad-spectrum antimycotic drug mainly used for the treatment of Candida albicans and other fungal infections. A synthetic, azole antimycotic, clotrimazole is widely used as a topical treatment for tinea pedis (athlete's foot), as well as vulvovaginal and oropharyngeal candidiasis. It displays fungistatic antimycotic activity by targeting the biosynthesis of ergosterol, thereby inhibiting fungal growth. As well as its antimycotic activity, clotrimazole has become a drug of interest against several other diseases such as sickle cell disease, malaria and some cancers. It has also been combined with other molecules, such as the metals, to produce clotrimazole complexes that show improved pharmacological efficacy. Moreover, several new, modified-release pharmaceutical formulations are also undergoing development. Clotrimazole is a very well-tolerated product with few side effects, although there is some drug resistance appearing among immunocompromised patients. Here, we review the pharmaceutical chemistry, application and pharmacology of clotrimazole and discuss future prospects for its further development as a chemotherapeutic agent.
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Affiliation(s)
- P D Crowley
- School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
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Molecular dynamics simulations of scorpion toxin recognition by the Ca(2+)-activated potassium channel KCa3.1. Biophys J 2014; 105:1829-37. [PMID: 24138859 DOI: 10.1016/j.bpj.2013.08.046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/26/2013] [Accepted: 08/30/2013] [Indexed: 02/06/2023] Open
Abstract
The Ca(2+)-activated channel of intermediate-conductance (KCa3.1) is a target for antisickling and immunosuppressant agents. Many small peptides isolated from animal venoms inhibit KCa3.1 with nanomolar affinities and are promising drug scaffolds. Although the inhibitory effect of peptide toxins on KCa3.1 has been examined extensively, the structural basis of toxin-channel recognition has not been understood in detail. Here, the binding modes of two selected scorpion toxins, charybdotoxin (ChTx) and OSK1, to human KCa3.1 are examined in atomic detail using molecular dynamics (MD) simulations. Employing a homology model of KCa3.1, we first determine conduction properties of the channel using Brownian dynamics and ascertain that the simulated results are in accord with experiment. The model structures of ChTx-KCa3.1 and OSK1-KCa3.1 complexes are then constructed using MD simulations biased with distance restraints. The ChTx-KCa3.1 complex predicted from biased MD is consistent with the crystal structure of ChTx bound to a voltage-gated K(+) channel. The dissociation constants (Kd) for the binding of both ChTx and OSK1 to KCa3.1 determined experimentally are reproduced within fivefold using potential of mean force calculations. Making use of the knowledge we gained by studying the ChTx-KCa3.1 complex, we attempt to enhance the binding affinity of the toxin by carrying out a theoretical mutagenesis. A mutant toxin, in which the positions of two amino acid residues are interchanged, exhibits a 35-fold lower Kd value for KCa3.1 than that of the wild-type. This study provides insight into the key molecular determinants for the high-affinity binding of peptide toxins to KCa3.1, and demonstrates the power of computational methods in the design of novel toxins.
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Jenkins DP, Yu W, Brown BM, Løjkner LD, Wulff H. Development of a QPatch automated electrophysiology assay for identifying KCa3.1 inhibitors and activators. Assay Drug Dev Technol 2013; 11:551-60. [PMID: 24351043 PMCID: PMC3870577 DOI: 10.1089/adt.2013.543] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The intermediate-conductance Ca(2+)-activated K(+) channel KCa3.1 (also known as KCNN4, IK1, or the Gárdos channel) plays an important role in the activation of T and B cells, mast cells, macrophages, and microglia by regulating membrane potential, cellular volume, and calcium signaling. KCa3.1 is further involved in the proliferation of dedifferentiated vascular smooth muscle cells and fibroblast and endothelium-derived hyperpolarization responses in the vascular endothelium. Accordingly, KCa3.1 inhibitors are therapeutically interesting as immunosuppressants and for the treatment of a wide range of fibroproliferative disorders, whereas KCa3.1 activators constitute a potential new class of endothelial function preserving antihypertensives. Here, we report the development of QPatch assays for both KCa3.1 inhibitors and activators. During assay optimization, the Ca(2+) sensitivity of KCa3.1 was studied using varying intracellular Ca(2+) concentrations. A free Ca(2+) concentration of 1 μM was chosen to optimally test inhibitors. To identify activators, which generally act as positive gating modulators, a lower Ca(2+) concentration (∼200 nM) was used. The QPatch results were benchmarked against manual patch-clamp electrophysiology by determining the potency of several commonly used KCa3.1 inhibitors (TRAM-34, NS6180, ChTX) and activators (EBIO, riluzole, SKA-31). Collectively, our results demonstrate that the QPatch provides a comparable but much faster approach to study compound interactions with KCa3.1 channels in a robust and reliable assay.
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Affiliation(s)
| | - Weifeng Yu
- Sophion Bioscience, Inc., North Brunswick, New Jersey
| | - Brandon M. Brown
- Department of Pharmacology, University of California, Davis, California
| | | | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California
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Endothelial small-conductance and intermediate-conductance KCa channels: an update on their pharmacology and usefulness as cardiovascular targets. J Cardiovasc Pharmacol 2013; 61:102-12. [PMID: 23107876 DOI: 10.1097/fjc.0b013e318279ba20] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Most cardiovascular researchers are familiar with intermediate-conductance KCa3.1 and small-conductance KCa2.3 channels because of their contribution to endothelium-derived hyperpolarization. However, to immunologists and neuroscientists, these channels are primarily known for their role in lymphocyte activation and neuronal excitability. KCa3.1 is involved in the proliferation and migration of T cells, B cells, mast cells, macrophages, fibroblasts, and dedifferentiated vascular smooth muscle cells and is, therefore, being pursued as a potential target for use in asthma, immunosuppression, and fibroproliferative disorders. In contrast, the 3 KCa2 channels (KCa2.1, KCa2.2, and KCa2.3) contribute to the neuronal medium afterhyperpolarization and, depending on the type of neuron, are involved in determining firing rates and frequencies or in regulating bursting. KCa2 activators are accordingly being studied as potential therapeutics for ataxia and epilepsy, whereas KCa2 channel inhibitors like apamin have long been known to improve learning and memory in rodents. Given this background, we review the recent discoveries of novel KCa3.1 and KCa2.3 modulators and critically assess the potential of KCa activators for the treatment of diabetes and cardiovascular diseases by improving endothelium-derived hyperpolarizations.
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Strøbæk D, Brown DT, Jenkins DP, Chen YJ, Coleman N, Ando Y, Chiu P, Jørgensen S, Demnitz J, Wulff H, Christophersen P. NS6180, a new K(Ca) 3.1 channel inhibitor prevents T-cell activation and inflammation in a rat model of inflammatory bowel disease. Br J Pharmacol 2013; 168:432-44. [PMID: 22891655 DOI: 10.1111/j.1476-5381.2012.02143.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 06/21/2012] [Accepted: 08/07/2012] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The K(Ca) 3.1 channel is a potential target for therapy of immune disease. We identified a compound from a new chemical class of K(Ca) 3.1 inhibitors and assessed in vitro and in vivo inhibition of immune responses. EXPERIMENTAL APPROACH We characterized the benzothiazinone NS6180 (4-[[3-(trifluoromethyl)phenyl]methyl]-2H-1,4-benzothiazin-3(4H)-one) with respect to potency and molecular site of action on K(Ca) 3.1 channels, selectivity towards other targets, effects on T-cell activation as well as pharmacokinetics and inflammation control in colitis induced by 2,4-dinitrobenzene sulfonic acid, a rat model of inflammatory bowel disease (IBD). KEY RESULTS NS6180 inhibited cloned human K(Ca) 3.1 channels (IC(50) = 9 nM) via T250 and V275, the same amino acid residues conferring sensitivity to triarylmethanes such as like TRAM-34. NS6180 inhibited endogenously expressed K(Ca) 3.1 channels in human, mouse and rat erythrocytes, with similar potencies (15-20 nM). NS6180 suppressed rat and mouse splenocyte proliferation at submicrolar concentrations and potently inhibited IL-2 and IFN-γ production, while exerting smaller effects on IL-4 and TNF-α and no effect on IL-17 production. Antibody staining showed K(Ca) 3.1 channels in healthy colon and strong up-regulation in association with infiltrating immune cells after induction of colitis. Despite poor plasma exposure, NS6180 (3 and 10 mg·kg(-1) b.i.d.) dampened colon inflammation and improved body weight gain as effectively as the standard IBD drug sulfasalazine (300 mg·kg(-1) q.d.). CONCLUSIONS AND IMPLICATIONS NS6180 represents a novel class of K(Ca) 3.1 channel inhibitors which inhibited experimental colitis, suggesting K(Ca) 3.1 channels as targets for pharmacological control of intestinal inflammation.
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Shmukler BE, Hsu A, Alves J, Trudel M, Rust MB, Hubner CA, Rivera A, Alper SL. N-ethylmaleimide activates a Cl(-)-independent component of K(+) flux in mouse erythrocytes. Blood Cells Mol Dis 2013; 51:9-16. [PMID: 23481459 PMCID: PMC3646938 DOI: 10.1016/j.bcmd.2013.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 02/04/2013] [Indexed: 11/17/2022]
Abstract
The K-Cl cotransporters (KCCs) of mouse erythrocytes exhibit higher basal activity than those of human erythrocytes, but are similarly activated by cell swelling, by hypertonic urea, and by staurosporine. However, the dramatic stimulation of human erythroid KCCs by N-ethylmaleimide (NEM) is obscured in mouse erythrocytes by a prominent NEM-stimulated K(+) efflux that lacks Cl(-)-dependence. The NEM-sensitivity of Cl(-)-independent K(+) efflux of mouse erythrocytes is lower than that of KCC. The genetically engineered absence of the K-Cl cotransporters KCC3 and KCC1 from mouse erythrocytes does not modify Cl(-)-independent K(+) efflux. Mouse erythrocytes genetically devoid of the Gardos channel KCNN4 show increased NEM-sensitivity of both Cl(-)-independent K(+) efflux and K-Cl cotransport. The increased NEM-sensitivity and stimulation magnitude of Cl(-)-independent K(+) efflux in mouse erythrocytes expressing transgenic hypersickling human hemoglobin SAD (HbSAD) are independent of the presence of KCC3 and KCC1, but absence of KCNN4 reduces the stimulatory effect of HbSAD. NEM-stimulated Cl(-)-independent K(+) efflux of mouse red cells is insensitive to ouabain and bumetanide, but partially inhibited by chloroquine, barium, and amiloride. The NEM-stimulated activity is modestly reduced at pH6.0 but not significantly altered at pH8.0, and is abolished at 0°C. Although the molecular identity of this little-studied K(+) efflux pathway of mouse erythrocytes remains unknown, its potential role in the pathophysiology of sickle red cell dehydration will be important for the extrapolation of studies in mouse models of sickle cell disease to our understanding of humans with sickle cell anemia.
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Affiliation(s)
- Boris E. Shmukler
- Divisions of Nephrology and Molecular and Vascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA
| | - Ann Hsu
- Divisions of Nephrology and Molecular and Vascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA
| | - Jessica Alves
- Department of Laboratory Medicine, Children’s Hospital, Boston, MA
| | - Marie Trudel
- Institut de Recherches Cliniques de Montréal, Molecular Genetics and Development, Faculte de Medecine, University of Montreal, Montreal
| | - Marco B. Rust
- Neurobiology/Neurophysiology Group, University of Kaiserslautern, Kaiserslautern, Germany
| | | | - Alicia Rivera
- Department of Laboratory Medicine, Children’s Hospital, Boston, MA
- Department of Pathology, Harvard Medical School, Boston, MA
| | - Seth L. Alper
- Divisions of Nephrology and Molecular and Vascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA
- Department of Medicine, Harvard Medical School, Boston, MA
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Bi D, Toyama K, Lemaître V, Takai J, Fan F, Jenkins DP, Wulff H, Gutterman DD, Park F, Miura H. The intermediate conductance calcium-activated potassium channel KCa3.1 regulates vascular smooth muscle cell proliferation via controlling calcium-dependent signaling. J Biol Chem 2013; 288:15843-53. [PMID: 23609438 PMCID: PMC3668741 DOI: 10.1074/jbc.m112.427187] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 04/12/2013] [Indexed: 01/14/2023] Open
Abstract
The intermediate conductance calcium-activated potassium channel KCa3.1 contributes to a variety of cell activation processes in pathologies such as inflammation, carcinogenesis, and vascular remodeling. We examined the electrophysiological and transcriptional mechanisms by which KCa3.1 regulates vascular smooth muscle cell (VSMC) proliferation. Platelet-derived growth factor-BB (PDGF)-induced proliferation of human coronary artery VSMCs was attenuated by lowering intracellular Ca(2+) concentration ([Ca(2+)]i) and was enhanced by elevating [Ca(2+)]i. KCa3.1 blockade or knockdown inhibited proliferation by suppressing the rise in [Ca(2+)]i and attenuating the expression of phosphorylated cAMP-response element-binding protein (CREB), c-Fos, and neuron-derived orphan receptor-1 (NOR-1). This antiproliferative effect was abolished by elevating [Ca(2+)]i. KCa3.1 overexpression induced VSMC proliferation, and potentiated PDGF-induced proliferation, by inducing CREB phosphorylation, c-Fos, and NOR-1. Pharmacological stimulation of KCa3.1 unexpectedly suppressed proliferation by abolishing the expression and activity of KCa3.1 and PDGF β-receptors and inhibiting the rise in [Ca(2+)]i. The stimulation also attenuated the levels of phosphorylated CREB, c-Fos, and cyclin expression. After KCa3.1 blockade, the characteristic round shape of VSMCs expressing high l-caldesmon and low calponin-1 (dedifferentiation state) was maintained, whereas KCa3.1 stimulation induced a spindle-shaped cellular appearance, with low l-caldesmon and high calponin-1. In conclusion, KCa3.1 plays an important role in VSMC proliferation via controlling Ca(2+)-dependent signaling pathways, and its modulation may therefore constitute a new therapeutic target for cell proliferative diseases such as atherosclerosis.
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Affiliation(s)
- Dan Bi
- From the Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557
| | - Kazuyoshi Toyama
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
| | - Vincent Lemaître
- From the Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557
| | - Jun Takai
- From the Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557
| | - Fan Fan
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
| | - David P. Jenkins
- the Department of Pharmacology, University of California, Davis, California 95616
| | - Heike Wulff
- the Department of Pharmacology, University of California, Davis, California 95616
| | - David D. Gutterman
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
| | - Frank Park
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
| | - Hiroto Miura
- From the Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557
- the Department of Medicine and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and
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Gee BE. Biologic complexity in sickle cell disease: implications for developing targeted therapeutics. ScientificWorldJournal 2013; 2013:694146. [PMID: 23589705 PMCID: PMC3621302 DOI: 10.1155/2013/694146] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 01/29/2013] [Indexed: 01/01/2023] Open
Abstract
Current therapy for sickle cell disease (SCD) is limited to supportive treatment of complications, red blood cell transfusions, hydroxyurea, and stem cell transplantation. Difficulty in the translation of mechanistically based therapies may be the result of a reductionist approach focused on individual pathways, without having demonstrated their relative contribution to SCD complications. Many pathophysiologic processes in SCD are likely to interact simultaneously to contribute to acute vaso-occlusion or chronic vasculopathy. Applying concepts of systems biology and network medicine, models were developed to show relationships between the primary defect of sickle hemoglobin (Hb S) polymerization and the outcomes of acute pain and chronic vasculopathy. Pathophysiologic processes such as inflammation and oxidative stress are downstream by-products of Hb S polymerization, transduced through secondary pathways of hemolysis and vaso-occlusion. Pain, a common clinical trials endpoint, is also complex and may be influenced by factors outside of sickle cell polymerization and vascular occlusion. Future sickle cell research needs to better address the biologic complexity of both sickle cell disease and pain. The relevance of individual pathways to important sickle cell outcomes needs to be demonstrated in vivo before investing in expensive and labor-intensive clinical trials.
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Affiliation(s)
- Beatrice E Gee
- Department of Pediatrics, Cardiovascular Research Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310-1495, USA.
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Abstract
The oxygenation state of erythrocytes is known to impact several cellular processes. As the only known O2-binding protein in red blood cells, haemoglobin has been implicated in the oxygenation-mediated control of cell pathways and properties. Band 3, an integral membrane protein linked to the spectrin/actin cytoskeleton, preferentially binds deoxygenated haemoglobin at its N-terminus, and has been postulated to participate in the mechanism by which oxygenation controls cellular processes. Because the ankyrin-binding site on band 3 is located near the deoxyHb (deoxygenated haemoglobin)-binding site, we hypothesized that deoxyHb might impact the association between band 3 and the underlying erythrocyte cytoskeleton, a link that is primarily established through band 3-ankyrin bridging. In the present paper we show that deoxygenation of human erythrocytes results in displacement of ankyrin from band 3, leading to release of the spectrin/actin cytoskeleton from the membrane. This weakening of membrane-cytoskeletal interactions during brief periods of deoxygenation could prove beneficial to blood flow, but during episodes of prolonged deoxygenation, such as during sickle cell occlusive crises, could promote unwanted membrane vesiculation.
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40
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Horng CT, Chiang NN, Chen IL, Liang WZ, Chen IS, Kuo DH, Shieh PC, Jan CR. Effect of clotrimazole on cytosolic Ca2+rise and viability in HA59T human hepatoma cells. J Recept Signal Transduct Res 2013; 33:89-95. [DOI: 10.3109/10799893.2013.764321] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Mukhopadhyay S, Das I, Das K. Selection of a stroke risk model based on transcranial Doppler ultrasound velocity. J Appl Stat 2012. [DOI: 10.1080/02664763.2012.725463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Balut CM, Hamilton KL, Devor DC. Trafficking of intermediate (KCa3.1) and small (KCa2.x) conductance, Ca(2+)-activated K(+) channels: a novel target for medicinal chemistry efforts? ChemMedChem 2012; 7:1741-55. [PMID: 22887933 DOI: 10.1002/cmdc.201200226] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 07/09/2012] [Indexed: 12/22/2022]
Abstract
Ca(2+)-activated K(+) (KCa) channels play a pivotal role in the physiology of a wide variety of tissues and disease states, including vascular endothelia, secretory epithelia, certain cancers, red blood cells (RBC), neurons, and immune cells. Such widespread involvement has generated an intense interest in elucidating the function and regulation of these channels, with the goal of developing pharmacological strategies aimed at selective modulation of KCa channels in various disease states. Herein we give an overview of the molecular and functional properties of these channels and their therapeutic importance. We discuss the achievements made in designing pharmacological tools that control the function of KCa channels by modulating their gating properties. Moreover, this review discusses the recent advances in our understanding of KCa channel assembly and anterograde trafficking toward the plasma membrane, the micro-domains in which these channels are expressed within the cell, and finally the retrograde trafficking routes these channels take following endocytosis. As the regulation of intracellular trafficking by agonists as well as the protein-protein interactions that modify these events continue to be explored, we anticipate this will open new therapeutic avenues for the targeting of these channels based on the pharmacological modulation of KCa channel density at the plasma membrane.
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Affiliation(s)
- Corina M Balut
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Abstract
BACKGROUND Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. OBJECTIVES To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 25 October 2011. SELECTION CRITERIA Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both authors independently selected studies for inclusion, assessed study quality and extracted data. MAIN RESULTS Of the 51 studies identified, three met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises. AUTHORS' CONCLUSIONS While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red cell survival (depending on dose), this did not lead to fewer painful crises.
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Affiliation(s)
- Srikanth Nagalla
- Department of Medicine, Division of Hematology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Borhade V, Pathak S, Sharma S, Patravale V. Clotrimazole nanoemulsion for malaria chemotherapy. Part II: Stability assessment, in vivo pharmacodynamic evaluations and toxicological studies. Int J Pharm 2012; 431:149-60. [DOI: 10.1016/j.ijpharm.2011.12.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 12/18/2011] [Accepted: 12/21/2011] [Indexed: 10/14/2022]
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Kuiper EFE, Nelemans A, Luiten P, Nijholt I, Dolga A, Eisel U. K(Ca)2 and k(ca)3 channels in learning and memory processes, and neurodegeneration. Front Pharmacol 2012; 3:107. [PMID: 22701424 PMCID: PMC3372087 DOI: 10.3389/fphar.2012.00107] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/19/2012] [Indexed: 11/13/2022] Open
Abstract
Calcium-activated potassium (KCa) channels are present throughout the central nervous system as well as many peripheral tissues. Activation of KCa channels contribute to maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP) that regulates action potential firing and limits the firing frequency of repetitive action potentials. Different subtypes of KCa channels were anticipated on the basis of their physiological and pharmacological profiles, and cloning revealed two well defined but phylogenetic distantly related groups of channels. The group subject of this review includes both the small conductance KCa2 channels (KCa2.1, KCa2.2, and KCa2.3) and the intermediate-conductance (KCa3.1) channel. These channels are activated by submicromolar intracellular Ca2+ concentrations and are voltage independent. Of all KCa channels only the KCa2 channels can be potently but differentially blocked by the bee-venom apamin. In the past few years modulation of KCa channel activation revealed new roles for KCa2 channels in controlling dendritic excitability, synaptic functioning, and synaptic plasticity. Furthermore, KCa2 channels appeared to be involved in neurodegeneration, and learning and memory processes. In this review, we focus on the role of KCa2 and KCa3 channels in these latter mechanisms with emphasis on learning and memory, Alzheimer’s disease and on the interplay between neuroinflammation and different neurotransmitters/neuromodulators, their signaling components and KCa channel activation.
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Affiliation(s)
- Els F E Kuiper
- Molecular Neurobiology, University of Groningen Groningen, Netherlands
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Wulff H, Castle NA. Therapeutic potential of KCa3.1 blockers: recent advances and promising trends. Expert Rev Clin Pharmacol 2012; 3:385-96. [PMID: 22111618 DOI: 10.1586/ecp.10.11] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The Ca(2+)-activated K(+) channel K(Ca)3.1 regulates membrane potential and calcium signaling in erythrocytes, activated T and B cells, macrophages, microglia, vascular endothelium, epithelia, and proliferating vascular smooth muscle cells and fibroblasts. K(Ca)3.1 has therefore been suggested as a potential therapeutic target for diseases such as sickle cell anemia, asthma, coronary restenosis after angioplasty, atherosclerosis, kidney fibrosis and autoimmunity, where activation and excessive proliferation of one or more of these cell types is involved in the pathology. This article will review the physiology and pharmacology of K(Ca)3.1 and critically examine the available preclinical and clinical data validating K(Ca)3.1 as a therapeutic target.
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Hirschler-Laszkiewicz I, Zhang W, Keefer K, Conrad K, Tong Q, Chen SJ, Bronson S, Cheung JY, Miller BA. Trpc2 depletion protects red blood cells from oxidative stress-induced hemolysis. Exp Hematol 2011; 40:71-83. [PMID: 21924222 DOI: 10.1016/j.exphem.2011.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 08/22/2011] [Accepted: 09/09/2011] [Indexed: 11/29/2022]
Abstract
Transient receptor potential (TRP) channels Trpc2 and Trpc3 are expressed on normal murine erythroid precursors, and erythropoietin stimulates an increase in intracellular calcium ([Ca(2+)](i)) through TRPC2 and TRPC3. Because modulation of [Ca(2+)](i) is an important signaling pathway in erythroid proliferation and differentiation, Trpc2, Trpc3, and Trpc2/Trpc3 double knockout mice were utilized to explore the roles of these channels in erythropoiesis. Trpc2, Trpc3, and Trpc2/Trpc3 double knockout mice were not anemic, and had similar red blood cell counts, hemoglobins, and reticulocyte counts as wild-type littermate controls. Although the erythropoietin-induced increase in [Ca(2+)](i) was reduced, these knockout mice showed no defects in red cell production. The major phenotypic difference at steady state was that the mean corpuscular volume, mean corpuscular hemoglobin, and hematocrit of red cells were significantly greater in Trpc2 and Trpc2/Trpc3 double knockout mice, and mean corpuscular hemoglobin concentration was significantly reduced. All hematological parameters in Trpc3 knockout mice were similar to controls. When exposed to phenylhydrazine, unlike the Trpc3 knockouts, Trpc2 and Trpc2/Trpc3 double knockout mice showed significant resistance to hemolysis. This was associated with a significant reduction in hydrogen peroxide-induced calcium influx in erythroblasts. Although erythropoietin-induced calcium influx through TRPC2 or TRPC3 is not critical for erythroid production, these data demonstrate that TRPC2 plays an important role in oxidative stress-induced hemolysis, which may be related to reduced calcium entry in red cells in the presence of Trpc2 depletion.
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Bartolommei G, Tadini-Buoninsegni F, Moncelli MR, Gemma S, Camodeca C, Butini S, Campiani G, Lewis D, Inesi G. The Ca2+-ATPase (SERCA1) is inhibited by 4-aminoquinoline derivatives through interference with catalytic activation by Ca2+, whereas the ATPase E2 state remains functional. J Biol Chem 2011; 286:38383-38389. [PMID: 21914795 DOI: 10.1074/jbc.m111.287276] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Several clotrimazole (CLT) and 4-aminoquinoline derivatives were synthesized and found to exhibit in vitro antiplasmodial activity with IC(50) ranging from nm to μm values. We report here that some of these compounds produce inhibition of rabbit sarcoplasmic reticulum Ca(2+)-ATPase (SERCA1) with IC(50) values in the μm range. The highest affinity for the Ca(2+)-ATPase was observed with NF1442 (N-((3-chlorophenyl)(4-((4-(7-chloroquinolin-4-yl)piperazin-1-yl)methyl)phenyl)methyl)-7-chloro-4-aminoquinoline) and NF1058 (N-((3-chlorophenyl)(4-(pyrrolidin-1-ylmethyl)phenyl)methyl)-7-chloro-4-aminoquinoline),yielding IC(50) values of 1.3 and 8.0 μm as demonstrated by measurements of steady state ATPase activity as well as single cycle charge transfer. Characterization of sequential reactions comprising the ATPase catalytic and transport cycle then demonstrated that NF1058, and similarly CLT, interferes with the mechanism of Ca(2+) binding and Ca(2+)-dependent enzyme activation (E(2) to E(1)·Ca(2) transition) required for formation of phosphorylated intermediate by ATP utilization. On the other hand, Ca(2+) independent phosphoenzyme formation by utilization of P(i) (i.e. reverse of the hydrolytic reaction in the absence of Ca(2+)) was not inhibited by NF1058 or CLT. Comparative experiments showed that the high affinity inhibitor thapsigargin interferes not only with Ca(2+) binding and phosphoenzyme formation with ATP but also with phosphoenzyme formation by utilization of P(i) even though this reaction does not require Ca(2+). It is concluded that NF1058 and CLT inhibit SERCA by stabilization of an E(2) state that, as opposed to that obtained with thapsigargin, retains the functional ability to form E(2)-P by reacting with P(i).
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Affiliation(s)
- Gianluca Bartolommei
- Department of Chemistry "Ugo Schiff," University of Florence, 50019 Sesto Fiorentino, Italy
| | | | - Maria Rosa Moncelli
- Department of Chemistry "Ugo Schiff," University of Florence, 50019 Sesto Fiorentino, Italy
| | - Sandra Gemma
- European Research Centre for Drug Discovery and Development and Department of Pharmaceutical and Applied Chemistry, University of Siena, 53100 Siena, Italy
| | - Caterina Camodeca
- European Research Centre for Drug Discovery and Development and Department of Pharmaceutical and Applied Chemistry, University of Siena, 53100 Siena, Italy
| | - Stefania Butini
- European Research Centre for Drug Discovery and Development and Department of Pharmaceutical and Applied Chemistry, University of Siena, 53100 Siena, Italy
| | - Giuseppe Campiani
- European Research Centre for Drug Discovery and Development and Department of Pharmaceutical and Applied Chemistry, University of Siena, 53100 Siena, Italy
| | - David Lewis
- California Pacific Medical Center Research Institute, San Francisco, California 94107
| | - Giuseppe Inesi
- California Pacific Medical Center Research Institute, San Francisco, California 94107
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Effects of disodium cromoglycate on cationic exchange of deoxygenated sickle cells. Eur J Pharmacol 2011; 665:13-8. [PMID: 21586281 DOI: 10.1016/j.ejphar.2011.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 05/03/2011] [Indexed: 10/18/2022]
Abstract
In the present work, we explored the way in which cromoglycate, a drug used to treat allergies acts on ion movements in sickle cells. Cells were either slowly deoxygenated by overnight exposure to nitrogen or acutely deoxygenated by exposure to metabisulfite, a strong reducing agent which induces sickling of red blood sickle cells. Flushing the cells with nitrogen increased the intracellular concentration of Na(+) and decreased the intracellular concentration of K(+) and the sum of the concentrations of the two cations. One hundred nM cromoglycate inhibited the decrease of intracellular K(+) and the increase of intracellular Na(+) induced by deoxygenation (n=17). Metabisulfite (100mM) increased the intracellular concentration of Ca(2+) (measured by Fura Red) (n=15) and the shape of the cells (measured by light scattering) (n=9). One μM cromoglycate partially inhibited these two responses. In conclusion, cromoglycate partially inhibits abnormal K(+) loss, Ca(2+) entry pathways or Ca(2+) channels opened by cell deoxygenation and ensuing membrane modifications and prevents cell sickling.
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Loganathan A, Linley JE, Rajput I, Hunter M, Lodge JPA, Sandle GI. Basolateral potassium (IKCa) channel inhibition prevents increased colonic permeability induced by chemical hypoxia. Am J Physiol Gastrointest Liver Physiol 2011; 300:G146-53. [PMID: 20966032 PMCID: PMC3025504 DOI: 10.1152/ajpgi.00472.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Major liver resection is associated with impaired intestinal perfusion and intestinal ischemia, resulting in decreased mucosal integrity, increased bacterial translocation, and an increased risk of postoperative sepsis. However, the mechanism by which ischemia impairs intestinal mucosal integrity is unclear. We therefore evaluated the role of Ca(2+)-sensitive, intermediate-conductance (IK(Ca)) basolateral potassium channels in enhanced intestinal permeability secondary to chemical hypoxia. The effects of chemical hypoxia induced by 100 μM dinitrophenol (DNP) and 5 mM deoxyglucose (DG) on basolateral IK(Ca) channel activity and whole cell conductance in intact human colonic crypts, and paracellular permeability (G(S)) in isolated colonic sheets, were determined by patch-clamp recording and transepithelial electrical measurements, respectively. DNP and DG rapidly stimulated IK(Ca) channels in cell-attached basolateral membrane patches and elicited a twofold increase (P = 0.004) in whole cell conductance in amphotericin B-permeabilized membrane patches, changes that were inhibited by the specific IK(Ca) channel blockers TRAM-34 (100 nM) and clotrimazole (CLT; 10 μM). In colonic sheets apically permeabilized with nystatin, DNP elicited a twofold increase (P = 0.005) in G(S), which was largely inhibited by the serosal addition of 50 μM CLT. We conclude that, in intestinal epithelia, chemical hypoxia increases G(S) through a mechanism involving basolateral IK(Ca) channel activation. Basolateral IK(Ca) channel inhibition may prevent or limit increased intestinal permeability during liver surgery.
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Affiliation(s)
- A. Loganathan
- 1Leeds Institute of Molecular Medicine and ,2Department of Hepatobiliary Surgery, St. James's University Hospital; and
| | - J. E. Linley
- 3Institute of Membrane and Systems Biology, University of Leeds, Leeds, United Kingdom
| | - I. Rajput
- 1Leeds Institute of Molecular Medicine and ,2Department of Hepatobiliary Surgery, St. James's University Hospital; and
| | - M. Hunter
- 3Institute of Membrane and Systems Biology, University of Leeds, Leeds, United Kingdom
| | - J. P. A. Lodge
- 2Department of Hepatobiliary Surgery, St. James's University Hospital; and
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