6 results on '"Romito O"'
Search Results
2. EPAC1 and 2 inhibit K + currents via PLC/PKC and NOS/PKG pathways in rat ventricular cardiomyocytes.
- Author
-
Boileve A, Romito O, Hof T, Levallois A, Brard L, d'Hers S, Fouchet A, Simard C, Guinamard R, Brette F, and Sallé L
- Subjects
- Animals, Rats, Cyclic GMP-Dependent Protein Kinases metabolism, Nitric Oxide Synthase metabolism, Nitric Oxide Synthase antagonists & inhibitors, Type C Phospholipases metabolism, Type C Phospholipases antagonists & inhibitors, Male, Rats, Wistar, Potassium metabolism, Cyclic AMP metabolism, Guanine Nucleotide Exchange Factors metabolism, Myocytes, Cardiac metabolism, Myocytes, Cardiac drug effects, Myocytes, Cardiac enzymology, Protein Kinase C metabolism, Signal Transduction, Action Potentials drug effects, Heart Ventricles metabolism, Heart Ventricles cytology
- Abstract
The exchange protein directly activated by cAMP (EPAC) has been implicated in cardiac proarrhythmic signaling pathways including spontaneous diastolic Ca
2+ leak from sarcoplasmic reticulum and increased action potential duration (APD) in isolated ventricular cardiomyocytes. The action potential (AP) lengthening following acute EPAC activation is mainly due to a decrease of repolarizing steady-state K+ current (IKSS ) but the mechanisms involved remain unknown. This study aimed to assess the role of EPAC1 and EPAC2 in the decrease of IKSS and to investigate the underlying signaling pathways. AP and K+ currents were recorded with the whole cell configuration of the patch-clamp technique in freshly isolated rat ventricular myocytes. EPAC1 and EPAC2 were pharmacologically activated with 8-(4-chlorophenylthio)-2'- O -methyl-cAMP acetoxymethyl ester (8-CPTAM, 10 µmol/L) and inhibited with R-Ce3F4 and ESI-05, respectively. Inhibition of EPAC1 and EPAC2 significantly decreased the effect of 8-CPTAM on APD and IKSS showing that both EPAC isoforms are involved in these effects. Unexpectedly, calmodulin-dependent protein kinase II (CaMKII) inhibition by AIP or KN-93, and Ca2+ chelation by intracellular BAPTA, did not impact the response to 8-CPTAM. However, inhibition of PLC/PKC and nitric oxide synthase (NOS)/PKG pathways partially prevents the 8-CPTAM-dependent decrease of IKSS . Finally, the cumulative inhibition of PKC and PKG blocked the 8-CPTAM effect, suggesting that these two actors work along parallel pathways to regulate IKSS upon EPAC activation. On the basis of such findings, we propose that EPAC1 and EPAC2 are involved in APD lengthening by inhibiting a K+ current via both PLC/PKC and NOS/PKG pathways. This may have pathological implications since EPAC is upregulated in diseases such as cardiac hypertrophy. NEW & NOTEWORHTY Exchange protein directly activated by cAMP (EPAC) proteins modulate ventricular electrophysiology at the cellular level. Both EPAC1 and EPAC2 isoforms participate in this effect. Mechanistically, PLC/PKC and nitric oxide synthase (NO)/PKG pathways are involved in regulating K+ repolarizing current whereas the well-known downstream effector of EPAC, calmodulin-dependent protein kinase II (CaMKII), does not participate. This may have pathological implications since EPAC is upregulated in diseases such as cardiac hypertrophy. Thus, EPAC inhibition may be a new approach to prevent arrhythmias under pathological conditions.- Published
- 2024
- Full Text
- View/download PDF
3. Plasma membrane SK2 channel activity regulates migration and chemosensitivity of high-grade serous ovarian cancer cells.
- Author
-
Romito O, Lemettre A, Chantôme A, Champion O, Couty N, Ouldamer L, Hempel N, Trebak M, Goupille C, and Potier-Cartereau M
- Subjects
- Humans, Female, Cell Line, Tumor, Drug Resistance, Neoplasm genetics, Lysophospholipids metabolism, Calcium metabolism, Ovarian Neoplasms pathology, Ovarian Neoplasms metabolism, Ovarian Neoplasms genetics, Ovarian Neoplasms drug therapy, Cell Movement drug effects, Cell Movement genetics, Small-Conductance Calcium-Activated Potassium Channels metabolism, Small-Conductance Calcium-Activated Potassium Channels genetics, Cell Membrane metabolism
- Abstract
No data are currently available on the functional role of small conductance Ca
2+ -activated K+ channels (SKCa) in ovarian cancer. Here, we characterized the role of SK2 (KCa2.2) in ovarian cancer cell migration and chemosensitivity. Using the selective non-cell-permeant SK2 inhibitor Lei-Dab7, we identified functional SK2 channels at the plasma membrane, regulating store-operated Ca2+ entry (SOCE) in both cell lines tested (COV504 and OVCAR3). Silencing KCNN2 with short interfering RNA (siRNA), or blocking SK2 activity with Lei-Dab7, decreased cell migration. The more robust effect of KCNN2 knockdown compared to Lei-Dab7 treatment suggested the involvement of functional intracellular SK2 channels in both cell lines. In cells treated with lysophosphatidic acid (LPA), an ovarian cancer biomarker of progression, SK2 channels are a key player of LPA pro-migratory activity but their role in SOCE is abolished. Concerning chemotherapy, SK2 inhibition increased chemoresistance to Taxol® and low KCNN2 mRNA expression was associated with the worst prognosis for progression-free survival in patients with serous ovarian cancer. The dual roles of SK2 mean that SK2 activators could be used as an adjuvant chemotherapy to potentiate treatment efficacy and SK2 inhibitors could be administrated as monotherapy to limit cancer cell dissemination., (© 2024 The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)- Published
- 2024
- Full Text
- View/download PDF
4. Enhanced macromolecular substance extravasation through the blood-brain barrier via acoustic bubble-cell interactions.
- Author
-
Chen J, Escoffre JM, Romito O, Iazourene T, Presset A, Roy M, Potier Cartereau M, Vandier C, Wang Y, Wang G, Huang P, and Bouakaz A
- Subjects
- Brain metabolism, Acoustics, Microbubbles, Coloring Agents, Drug Delivery Systems methods, Cell Communication, Blood-Brain Barrier metabolism, Dextrans
- Abstract
The blood-brain barrier (BBB) maintains brain homeostasis, regulates influx and efflux transport, and provides protection to the brain tissue. Ultrasound (US) and microbubble (MB)-mediated blood-brain barrier opening is an effective and safe technique for drug delivery in-vitro and in-vivo. However, the exact mechanism underlying this technique is still not fully elucidated. The aim of the study is to explore the contribution of transcytosis in the BBB transient opening using an in-vitro model of BBB. Utilizing a diverse set of techniques, including Ca
2+ imaging, electron microscopy, and electrophysiological recordings, our results showed that the combined use of US and MBs triggers membrane deformation within the endothelial cell membrane, a phenomenon primarily observed in the US + MBs group. This deformation facilitates the vesicles transportation of 500 kDa fluorescent Dextran via dynamin-/caveolae-/clathrin- mediated transcytosis pathway. Simultaneously, we observed increase of cytosolic Ca2+ concentration, which is related with increased permeability of the 500 kDa fluorescent Dextran in-vitro. This was found to be associated with the Ca2+ -protein kinase C (PKC) signaling pathway. The insights provided by the acoustically-mediated interaction between the microbubbles and the cells delineate potential mechanisms for macromolecular substance permeability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
5. A multiple-oscillator mechanism underlies antigen-induced Ca 2+ oscillations in Jurkat T-cells.
- Author
-
Benson JC, Romito O, Abdelnaby AE, Xin P, Pathak T, Weir SE, Kirk V, Castaneda F, Yoast RE, Emrich SM, Tang PW, Yule DI, Hempel N, Potier-Cartereau M, Sneyd J, and Trebak M
- Subjects
- Humans, Calcium metabolism, Jurkat Cells, Stromal Interaction Molecule 1 genetics, Stromal Interaction Molecule 1 metabolism, Stromal Interaction Molecule 2 genetics, Stromal Interaction Molecule 2 metabolism, Gene Knockout Techniques, Models, Biological, Protein Isoforms, Protein Transport genetics, Cell Proliferation genetics, Cell Survival genetics, Calcium Release Activated Calcium Channels genetics, Calcium Release Activated Calcium Channels metabolism, Calcium Signaling genetics
- Abstract
T-cell receptor stimulation triggers cytosolic Ca
2+ signaling by inositol-1,4,5-trisphosphate (IP3 )-mediated Ca2+ release from the endoplasmic reticulum (ER) and Ca2+ entry through Ca2+ release-activated Ca2+ (CRAC) channels gated by ER-located stromal-interacting molecules (STIM1/2). Physiologically, cytosolic Ca2+ signaling manifests as regenerative Ca2+ oscillations, which are critical for nuclear factor of activated T-cells-mediated transcription. In most cells, Ca2+ oscillations are thought to originate from IP3 receptor-mediated Ca2+ release, with CRAC channels indirectly sustaining them through ER refilling. Here, experimental and computational evidence support a multiple-oscillator mechanism in Jurkat T-cells whereby both IP3 receptor and CRAC channel activities oscillate and directly fuel antigen-evoked Ca2+ oscillations, with the CRAC channel being the major contributor. KO of either STIM1 or STIM2 significantly reduces CRAC channel activity. As such, STIM1 and STIM2 synergize for optimal Ca2+ oscillations and activation of nuclear factor of activated T-cells 1 and are essential for ER refilling. The loss of both STIM proteins abrogates CRAC channel activity, drastically reduces ER Ca2+ content, severely hampers cell proliferation and enhances cell death. These results clarify the mechanism and the contribution of STIM proteins to Ca2+ oscillations in T-cells., Competing Interests: Conflict of interest Mohamed Trebak is a consultant for Seeker Biologics Inc, and is a member of the editorial board of the J. Biol. Chem. The remaining authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2023
- Full Text
- View/download PDF
6. Calcium signaling: A therapeutic target to overcome resistance to therapies in cancer.
- Author
-
Romito O, Guéguinou M, Raoul W, Champion O, Robert A, Trebak M, Goupille C, and Potier-Cartereau M
- Subjects
- Humans, Calcium, Carcinogenesis, Calcium Channels, Calcium Signaling, Neoplasms drug therapy
- Abstract
Innate and acquired resistances to therapeutic agents are responsible for the failure of cancer treatments. Due to the multifactorial nature of resistance, the identification of new therapeutic targets is required to improve cancer treatment. Calcium is a universal second messenger that regulates many cellular functions such as proliferation, migration, and survival. Calcium channels, pumps and exchangers tightly regulate the duration, location and magnitude of calcium signals. Many studies have implicated dysregulation of calcium signaling in several pathologies, including cancer. Abnormal calcium fluxes due to altered channel expression or activation contribute to carcinogenesis and promote tumor development. However, there is limited information on the role of calcium signaling in cancer resistance to therapeutic drugs. This review discusses the role of calcium signaling as a mediator of cancer resistance, and assesses the potential value of combining anticancer therapy with calcium signaling modulators to improve the effectiveness of current treatments., Competing Interests: Declaration of Competing Interest Mohamed Trebak is a paid consultant of Seeker Biologics Inc. The other authors declare that they have no conflict of interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.