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Remigante A, Spinelli S, Zuccolini P, Gavazzo P, Marino A, Pusch M, Morabito R, Dossena S. Melatonin protects Kir2.1 function in an oxidative stress-related model of aging neuroglia. Biofactors 2024; 50:523-541. [PMID: 38095328 DOI: 10.1002/biof.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/01/2023] [Indexed: 06/15/2024]
Abstract
Melatonin is a pleiotropic biofactor and an effective antioxidant and free radical scavenger and, as such, can be protective in oxidative stress-related brain conditions including epilepsy and aging. To test the potential protective effect of melatonin on brain homeostasis and identify the corresponding molecular targets, we established a new model of oxidative stress-related aging neuroglia represented by U-87 MG cells exposed to D-galactose (D-Gal). This model was characterized by a substantial elevation of markers of oxidative stress, lipid peroxidation, and protein oxidation. The function of the inward rectifying K+ channel Kir2.1, which was identified as the main Kir channel endogenously expressed in these cells, was dramatically impaired. Kir2.1 was unlikely a direct target of oxidative stress, but the loss of function resulted from a reduction of protein abundance, with no alterations in transcript levels and trafficking to the cell surface. Importantly, melatonin reverted these changes. All findings, including the melatonin antioxidant effect, were reproduced in heterologous expression systems. We conclude that the glial Kir2.1 can be a target of oxidative stress and further suggest that inhibition of its function might alter the extracellular K+ buffering in the brain, therefore contributing to neuronal hyperexcitability and epileptogenesis during aging. Melatonin can play a protective role in this context.
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Affiliation(s)
- Alessia Remigante
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Sara Spinelli
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Paolo Zuccolini
- Institute of Biophysics, National Research Council, Genova, Italy
| | - Paola Gavazzo
- Institute of Biophysics, National Research Council, Genova, Italy
| | - Angela Marino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Michael Pusch
- Institute of Biophysics, National Research Council, Genova, Italy
| | - Rossana Morabito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
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Bernardinelli E, Roesch S, Simoni E, Marino A, Rasp G, Astolfi L, Sarikas A, Dossena S. Novel POU3F4 variants identified in patients with inner ear malformations exhibit aberrant cellular distribution and lack of SLC6A20 transcriptional upregulation. Front Mol Neurosci 2022; 15:999833. [PMID: 36245926 PMCID: PMC9558712 DOI: 10.3389/fnmol.2022.999833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/13/2022] [Indexed: 11/14/2022] Open
Abstract
Hearing loss (HL) is the most common sensory defect and affects 450 million people worldwide in a disabling form. Pathogenic sequence alterations in the POU3F4 gene, which encodes a transcription factor, are causative of the most common type of X-linked deafness (X-linked deafness type 3, DFN3, DFNX2). POU3F4-related deafness is characterized by a typical inner ear malformation, namely an incomplete partition of the cochlea type 3 (IP3), with or without an enlargement of the vestibular aqueduct (EVA). The pathomechanism underlying POU3F4-related deafness and the corresponding transcriptional targets are largely uncharacterized. Two male patients belonging to a Caucasian cohort with HL and EVA who presented with an IP3 were submitted to genetic analysis. Two novel sequence variants in POU3F4 were identified by Sanger sequencing. In cell-based assays, the corresponding protein variants (p.S74Afs*8 and p.C327*) showed an aberrant expression and subcellular distribution and lack of transcriptional activity. These two protein variants failed to upregulate the transcript levels of the amino acid transporter gene SLC6A20, which was identified as a novel transcriptional target of POU3F4 by RNA sequencing and RT-qPCR. Accordingly, POU3F4 silencing by siRNA resulted in downregulation of SLC6A20 in mouse embryonic fibroblasts. Moreover, we showed for the first time that SLC6A20 is expressed in the mouse cochlea, and co-localized with POU3F4 in the spiral ligament. The findings presented here point to a novel role of amino acid transporters in the inner ear and pave the way for mechanistic studies of POU3F4-related HL.
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Affiliation(s)
- Emanuele Bernardinelli
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Sebastian Roesch
- Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University, Salzburg, Austria
| | - Edi Simoni
- Bioacoustic Research Laboratory, Department of Neuroscience, Biomedical Campus Pietro d’Abano, University of Padua, Padua, Italy
| | - Angela Marino
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Messina, Italy
| | - Gerd Rasp
- Department of Otorhinolaryngology, Head and Neck Surgery, Paracelsus Medical University, Salzburg, Austria
| | - Laura Astolfi
- Bioacoustic Research Laboratory, Department of Neuroscience, Biomedical Campus Pietro d’Abano, University of Padua, Padua, Italy
- Interdepartmental Research Center of International Auditory Processing Project in Venice (I-APPROVE), Department of Neurosciences, University of Padova, Santi Giovanni e Paolo Hospital, ULSS3, Venice, Italy
| | - Antonio Sarikas
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
- *Correspondence: Antonio Sarikas,
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
- Silvia Dossena,
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Rouka E, Kotsiou OS, Kyriakou D, Gourgoulianis KI, Zarogiannis SG. Pleural effusions induced by human herpesviruses in the immunocompetent host. Infect Dis (Lond) 2019; 51:189-196. [PMID: 30676829 DOI: 10.1080/23744235.2018.1551620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
METHODS A computer-based search of the English literature for articles relative to Human Herpesviruses (HHVs) infection and pleural effusions (PEs) in the immunocompetent host was performed in PubMed and Scopus. The reference lists of the retrieved articles were also reviewed for relevant articles. RESULTS A total of 20 articles satisfied the selection criteria and were included in the study. In the majority of the articles, PEs were reported as clinical complications of systemic HHV-induced infection. The frequency of HHVs within the reported cases was five for HHV-1/2, one for HHV-3, six for HHV-4, six for HHV-5 and one for HHV-6. One case involved HHV-4 and HHV-5 co-infection. No case of HHV-7 or HHV-8 related PE in the immunocompetent host was retrieved. CONCLUSIONS Pleural effusions in the immunocompetent host occur in severe viral infections and can be due to comorbidities (or septic complications) or due to the direct HHV pathogenicity although research relative to the susceptibility of pleural mesothelial cells to HHV infection is lacking. HHV pathogenicity needs to be studied further as it could explain undiagnosed PEs.
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Affiliation(s)
- Erasmia Rouka
- a Department of Transfusion Medicine , Faculty of Medicine, University of Thessaly, BIOPOLIS , Larissa , Greece.,b Department of Physiology , Faculty of Medicine, University of Thessaly, BIOPOLIS , Larissa , Greece
| | - Ourania S Kotsiou
- c Department of Respiratory Medicine , Faculty of Medicine, University of Thessaly, BIOPOLIS , Larissa , Greece
| | - Despoina Kyriakou
- a Department of Transfusion Medicine , Faculty of Medicine, University of Thessaly, BIOPOLIS , Larissa , Greece
| | | | - Sotirios G Zarogiannis
- b Department of Physiology , Faculty of Medicine, University of Thessaly, BIOPOLIS , Larissa , Greece.,c Department of Respiratory Medicine , Faculty of Medicine, University of Thessaly, BIOPOLIS , Larissa , Greece
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Bernardinelli E, Costa R, Scantamburlo G, To J, Morabito R, Nofziger C, Doerrier C, Krumschnabel G, Paulmichl M, Dossena S. Mis-targeting of the mitochondrial protein LIPT2 leads to apoptotic cell death. PLoS One 2017; 12:e0179591. [PMID: 28628643 PMCID: PMC5476274 DOI: 10.1371/journal.pone.0179591] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 06/01/2017] [Indexed: 11/27/2022] Open
Abstract
Lipoyl(Octanoyl) Transferase 2 (LIPT2) is a protein involved in the post-translational modification of key energy metabolism enzymes in humans. Defects of lipoic acid synthesis and transfer start to emerge as causes of fatal or severe early-onset disease. We show that the first 31 amino acids of the N-terminus of LIPT2 represent a mitochondrial targeting sequence and inhibition of the transit of LIPT2 to the mitochondrion results in apoptotic cell death associated with activation of the apoptotic volume decrease (AVD) current in normotonic conditions, as well as over-activation of the swelling-activated chloride current (IClswell), mitochondrial membrane potential collapse, caspase-3 cleavage and nuclear DNA fragmentation. The findings presented here may help elucidate the molecular mechanisms underlying derangements of lipoic acid biosynthesis.
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Affiliation(s)
- Emanuele Bernardinelli
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Roberta Costa
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Giada Scantamburlo
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | - Janet To
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Rossana Morabito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Charity Nofziger
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
| | | | | | - Markus Paulmichl
- Center for Health and Bioresources, Austrian Institute of Technology, Vienna, Austria
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
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Kaifi JT, Toth JW, Gusani NJ, Kimchi ET, Staveley-O'Carroll KF, Belani CP, Reed MF. Multidisciplinary management of malignant pleural effusion. J Surg Oncol 2011; 105:731-8. [PMID: 21960207 DOI: 10.1002/jso.22100] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 09/01/2011] [Indexed: 01/15/2023]
Affiliation(s)
- Jussuf T Kaifi
- Section of Surgical Oncology, Department of Surgery, Penn State Hershey Cancer Institute, Penn State College of Medicine, Hershey, Pennsylvania, USA.
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Dossena S, Gandini R, Tamma G, Vezzoli V, Nofziger C, Tamplenizza M, Salvioni E, Bernardinelli E, Meyer G, Valenti G, Wolf-Watz M, Fürst J, Paulmichl M. The molecular and functional interaction between ICln and HSPC038 proteins modulates the regulation of cell volume. J Biol Chem 2011; 286:40659-70. [PMID: 21917931 PMCID: PMC3220508 DOI: 10.1074/jbc.m111.260430] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Identifying functional partners for protein/protein interactions can be a difficult challenge. We proposed the use of the operon structure of the Caenorhabditis elegans genome as a “new gene-finding tool” (Eichmüller, S., Vezzoli, V., Bazzini, C., Ritter, M., Fürst, J., Jakab, M., Ravasio, A., Chwatal, S., Dossena, S., Bottà, G., Meyer, G., Maier, B., Valenti, G., Lang, F., and Paulmichl, M. (2004) J. Biol. Chem. 279, 7136–7146) that could be functionally translated to the human system. Here we show the validity of this approach by studying the predicted functional interaction between ICln and HSPC038. In C. elegans, the gene encoding for the ICln homolog (icln-1) is embedded in an operon with two other genes, Nx (the human homolog of Nx is HSPC038) and Ny. ICln is a highly conserved, ubiquitously expressed multifunctional protein that plays a critical role in the regulatory volume decrease after cell swelling. Following hypotonic stress, ICln translocates from the cytosol to the plasma membrane, where it has been proposed to participate in the activation of the swelling-induced chloride current (IClswell). Here we show that the interaction between human ICln and HSPC038 plays a role in volume regulation after cell swelling and that HSPC038 acts as an escort, directing ICln to the cell membrane after cell swelling and facilitating the activation of IClswell. Assessment of the NMR structure of HSPC038 showed the presence of a zinc finger motif. Moreover, NMR and additional biochemical techniques enabled us to identify the putative ICln/HSPC038 interacting sites, thereby explaining the functional interaction of both proteins on a molecular level.
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Affiliation(s)
- Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, A-5020 Salzburg, Austria.
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Kremer R, Best LA, Savulescu D, Gavish M, Nagler RM. Pleural fluid analysis of lung cancer vs benign inflammatory disease patients. Br J Cancer 2010; 102:1180-4. [PMID: 20216542 PMCID: PMC2853096 DOI: 10.1038/sj.bjc.6605607] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Correct diagnosis of pleural effusion (PE) as either benign or malignant is crucial, although conventional cytological evaluation is of limited diagnostic accuracy, with relatively low sensitivity rates. METHODS We identified biological markers accurately detected in a simple PE examination. We analysed data from 19 patients diagnosed with lung cancer (nine adeno-Ca, five non-small-cell Ca (not specified), four squamous-cell Ca, one large-cell Ca) and 22 patients with benign inflammatory pathologies: secondary to trauma, pneumonia or TB. RESULTS Pleural effusion concentrations of seven analysed biological markers were significantly lower in lung cancer patients than in benign inflammatory patients, especially in matrix metalloproteinase (MMP)-9, MMP-3 and CycD1 (lower by 65% (P<0.000003), 40% (P<0.0007) and 34% (P<0.0001), respectively), and in Ki67, ImAnOx, carbonyls and p27. High rates of sensitivity and specificity values were found for MMP-9, MMP-3 and CycD1: 80 and 100%; 87 and 73%; and 87 and 82%, respectively. CONCLUSION Although our results are of significant merit in both the clinical and pathogenetic aspects of lung cancer, further research aimed at defining the best combination for marker analysis is warranted. The relative simplicity in analysing these markers in any routine hospital laboratory may result in its acceptance as a new diagnostic tool.
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Affiliation(s)
- R Kremer
- Department of General Thoracic Surgery, Rambam Health Care Campus, Haifa, Israel
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Functional and molecular characterizations of chloride channels in rat pleural mesothelial cells. Eur J Pharmacol 2009; 614:22-9. [DOI: 10.1016/j.ejphar.2009.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 04/27/2009] [Accepted: 05/07/2009] [Indexed: 11/20/2022]
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Larkin D, Treumann A, Murphy D, DeChaumont C, Kiernan A, Moran N. Compartmentalization regulates the interaction between the platelet integrin alpha IIb beta 3 and ICln. Br J Haematol 2008; 144:580-90. [PMID: 19055659 DOI: 10.1111/j.1365-2141.2008.07483.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The volume-regulating protein, ICln, interacts with the conserved KxGFFKR alpha-integrin signature motif. ICln is an abundant protein (4455 +/- 650 molecules/platelet) found exclusively in the soluble cytosolic fraction of unactivated platelets. In contrast, its binding partner, the platelet integrin alpha(IIb)beta(3), is present in detergent-insoluble fractions associated with membrane and cytoskeleton subcellular localizations. This study investigated factors that regulate the interaction of ICln with alpha(IIb)beta(3) during platelet activation. His-tagged recombinant ICln bound equally to purified alpha(IIb)beta(3) and to integrin from resting or activated platelets. Binding was not affected by direct integrin activation with Mn(++) or by inhibitors of integrin occupancy (abciximab, RGD). However, the capacity for interaction between integrin and recombinant ICln was slowly downregulated following prolonged platelet activation for >300 s. In parallel, ICln redistributed to membrane and cytoskeletal platelet subcellular fractions. The time-course of this redistribution preceded the downregulation of integrin binding capacity and suggests that only a short window of opportunity exists for ICln interaction with alpha(IIb)beta(3) to occur. Thus, although ICln has the inherent capacity to bind to alpha(IIb)beta(3) regardless of its activation state, it can only do so following platelet activation. Activation-dependent subcellular redistribution of ICln represents a novel, temporally-regulated mechanism for control of integrin function in platelets.
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Affiliation(s)
- Deirdre Larkin
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
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Li G, Olson JE. Purinergic activation of anion conductance and osmolyte efflux in cultured rat hippocampal neurons. Am J Physiol Cell Physiol 2008; 295:C1550-60. [PMID: 18923056 DOI: 10.1152/ajpcell.90605.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The majority of mammalian cells demonstrate regulatory volume decrease (RVD) following swelling caused by hyposmotic exposure. A critical signal initiating RVD is activation of nucleotide receptors by ATP. Elevated extracellular ATP in response to cytotoxic cell swelling during pathological conditions also may initiate loss of taurine and other intracellular osmolytes via anion channels. This study characterizes neuronal ATP-activated anion current and explores its role in net loss of amino acid osmolytes. To isolate anion currents, we used CsCl as the major electrolyte in patch electrode and bath solutions and blocked residual cation currents with NiCl(2) and tetraethylammonium. Anion currents were activated by extracellular ATP with a K(m) of 70 microM and increased over fourfold during several minutes of ATP exposure, reaching a maximum after 9.0 min (SD 4.2). The currents were blocked by inhibitors of nucleotide receptors and volume-regulated anion channels (VRAC). Currents showed outward rectification and inactivation at highly depolarizing membrane potentials, characteristics of swelling-activated anion currents. P2X agonists failed to activate the anion current, and an inhibitor of P2X receptors did not block the effect of ATP. Furthermore, current activation was observed with extracellular ADP and 2-(methylthio)adenosine 5'-diphosphate, a P2Y(1) receptor-specific agonist. Much less current activation was observed with extracellular UTP, suggesting the response is mediated predominantly by P2Y(1) receptors. ATP caused a dose-dependent loss of taurine and alanine that could be blocked by inhibitors of VRAC. ATP did not inhibit the taurine uptake transporter. Thus extracellular ATP triggers a loss of intracellular organic osmolytes via activation of anion channels. This mechanism may facilitate neuronal volume homeostasis during cytotoxic edema.
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Affiliation(s)
- Guangze Li
- Dept. of Emergency Medicine, Wright State Univ., Boonshoft School of Medicine, Kettering, OH 45429, USA
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Abstract
Mesothelial cells are specialized epithelial cells, which line the pleural, pericardial, and peritoneal cavities. Accumulating evidence suggests that the monolayer of mesothelial cells is permeable to electrolyte and fluid, and thereby govern both fluid secretion and re-absorption in the serosal cavities. Disorders in these salt and fluid transport systems may be fundamental in the pathogenesis of pleural effusion, pericardial effusion, and ascites. In this review, we discuss the location, physiological function, and regulation of active transport (Na(+)-K(+)-ATPase) systems, cation and anion channels (Na(+), K(+), Cl(-), and Ca(2+) channels), antiport (exchangers) systems, and symport (co-transporters) systems, and water channels (aquaporins). These secretive and absorptive pathways across mesothelial monolayer cells for electrolytes and fluid may provide pivotal therapeutical targets for novel clinical intervention in edematous diseases of serous cavities.
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Affiliation(s)
- Hong-Long Ji
- Department of Biochemistry, Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, TX 75708, USA
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Neragi-Miandoab S. Malignant pleural effusion, current and evolving approaches for its diagnosis and management. Lung Cancer 2006; 54:1-9. [PMID: 16893591 DOI: 10.1016/j.lungcan.2006.04.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Revised: 04/01/2006] [Accepted: 04/11/2006] [Indexed: 10/24/2022]
Abstract
Malignant pleural effusion is a common and debilitating complication of advanced malignant diseases. This problem seems to affect particularly those with lung and breast cancer, contributing to the poor quality of life. Approximately half of all patients with metastatic cancer develop a malignant pleural effusion at some point, which is likely to cause significant symptoms such as dyspnea and cough. Evacuation of the pleural fluid and prevention of its re-accumulation are the main goals of management. Optimal treatment is controversial and there is no universally standard approach. Intervention options range from observation in the case of asymptomatic effusions through simple thoracentesis to more invasive methods such as chemical and mechanical pleurodesis, pleur-X catheter drainage, pleuroperitoneal shunting, and pleurectomy. The best results are reported with thoracoscopy and talc insufflation, with an acceptable morbidity. Development of novel methods to control malignant pleural effusion should be a high priority in palliative care of cancer patients. This article reviews the current, as well as, novel approaches that show some promise for the future. The aim is to identify the proper approach for each individual patient.
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Affiliation(s)
- Siyamek Neragi-Miandoab
- Thoracic and Cardiovascular Surgery, Loyola University Chicago, Stritch School of Medicine, 2160 South First Ave., Building 110, Room 6243, Maywood, IL 60153, USA.
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Fulgenzi G, Graciotti L, Faronato M, Soldovieri MV, Miceli F, Amoroso S, Annunziato L, Procopio A, Taglialatela M. Human neoplastic mesothelial cells express voltage-gated sodium channels involved in cell motility. Int J Biochem Cell Biol 2006; 38:1146-59. [PMID: 16458569 DOI: 10.1016/j.biocel.2005.12.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 11/26/2005] [Accepted: 12/08/2005] [Indexed: 02/07/2023]
Abstract
Given the pivotal role of ion channels in neoplastic transformation, the aim of the present study has been to assess possible differences in the expression patterns of voltage-gated monovalent cationic (Na(+) and K(+)) currents between normal and neoplastic mesothelial cells (NM, MPM, respectively), and to evaluate the role of specific ion channels in mesothelioma cells proliferation, apoptosis, and motility. To achieve this aim, membrane currents expressed in NM and MPM cells derived from surgically-removed human specimens were investigated by means of patch-clamp electrophysiology. NM cells were found to express three main classes of K(+) currents, which were defined as K(IR), maxiK(Ca), and K(V) currents on the basis of their biophysical and pharmacological properties. Each of these K(+) currents was absent in MPM cells; by contrast, MPM cells revealed the novel appearance of tetrodotoxin (TTX)-sensitive voltage-gated Na(+) currents undetected in normal mesothelial cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR analysis of MPM cells transcripts showed significant expression of the mRNAs encoding for Na(V)1.2, and Na(V)1.6, and Na(V)1.7 (and less so for Na(V)1.3, Na(V)1.4, and Na(V)1.5) main voltage-gated sodium channel (VGSC) alpha-subunit(s). Interestingly, blockade of VGSCs with TTX decreased mesothelioma cell migration in in vitro motility assays; on the other hand, TTX failed to interfere with cell viability, proliferation, and apoptosis progression triggered by UV exposure. In summary, the results of the present study suggest that VGSCs expression in MPM cells may favor the increased motility of the neoplastic cells, a phenotypic feature often associated with the malignant phenotype.
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Affiliation(s)
- Gianluca Fulgenzi
- Department of Molecular Pathology and Innovative Therapies, Polytechnic University of Marche, Via Ranieri, Ancona 60131, Italy
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Yeung CH, Barfield JP, Cooper TG. Chloride Channels in Physiological Volume Regulation of Human Spermatozoa1. Biol Reprod 2005; 73:1057-63. [PMID: 16033995 DOI: 10.1095/biolreprod.105.044123] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
As with other mammalian species, human spermatozoa experience a decrease in extracellular osmolarity in cervical mucus upon ejaculation, which requires the efflux of osmolytes and water to counteract swelling that hinders mucus penetration. Recent evidence for the operation of K+ channels in the process of volume regulation suggests parallel involvement of Cl-/anion channels for electro-neutrality as in somatic cells. This was studied using ejaculated spermatozoa washed at seminal osmolality and incubated for 30 min in a medium of mucus osmolality in the presence of Cl- channel blockers. Increases in cell size measured as laser forward-scatter by flow cytometry were detected in the presence of 100 microM 5-nitro-2(3-phenylpropylamino) benzoic acid, 400 microM diisothiocyanato-stilbene-2,2'-disulphonic acid, and 20 microM tamoxifen. No volume changes were found with 400 microM 4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulphonic acid, 200 microM verapamil, or niflumic acid, whereas 1 mM niflumic acid induced shrinkage. Among the candidate channel proteins, Western blotting revealed the presence of ClC-3 (CLCN3) at 87 kDa, but the absence of ClC-2 (CLCN2) from sperm proteins in all samples tested. ICln (CLNS1A) was found in only one of eight samples. Immunocytochemistry localized CLCN3 to the sperm tail. To confirm molecular identities, sperm mRNA was extracted and checked for quality by the presence of protamine 2 transcripts and the absence of sperm DNA and leukocyte mRNA using reverse transcription-polymerase chain reaction. Transcripts of Clcn3 were found in all samples and that of Clns1a in some but not all samples. Clcn3 was therefore considered the most likely candidate of Cl- channel involved in volume regulation of human sperm.
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Affiliation(s)
- C H Yeung
- Institute of Reproductive Medicine of the University, D-48129 Münster, Germany.
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