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Fahanik-Babaei J, Bagheri M, Salari S. Characterization of a novel Ca 2+-Activated potassium channel in rat brain rough endoplasmic reticulum. Arch Biochem Biophys 2024; 759:110105. [PMID: 39059600 DOI: 10.1016/j.abb.2024.110105] [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: 03/06/2024] [Revised: 07/23/2024] [Accepted: 07/24/2024] [Indexed: 07/28/2024]
Abstract
OBJECTIVES Potassium channels in the endoplasmic reticulum (ER) are crucial for maintaining calcium balance during calcium fluxes. Disruption in ER calcium balance leads to ER stress, implicated in diseases like diabetes and Alzheimer's disease (AD). However, limited data exists on ER potassium channels in excitable tissues such as the brain. To fill this gap, we aimed to evaluate potassium currents in rat brain rough endoplasmic reticulum (RER). METHODS Rats were euthanized under deep anesthesia and their brains were immediately removed. The brains were then homogenized in ice-cold sucrose buffer, followed by the extraction of RER microsomes through a series of centrifugation processes. Purity of sample was evaluated using western blotting technique. Single channel recordings were done in voltage steps from +50 to -60 mV following incorporation of rat brain RER vesicles into planar bilayers. RESULTS We observed a voltage-dependent potassium channel with an approximate conductance of 188 pS. Channel open probability was low at negative voltages, increasing at positive voltages. The channel was blocked by Charybdotoxin but not by Iberiotoxin. Additionally, TRAM-34, a specific KCa3.1 channel blocker, suppressed channel current amplitude and open probability. Western blot analysis revealed specific bands for anti-KCa3.1 antibody, approximately 50 kDa in brain homogenate and RER fraction. CONCLUSION Our study provides strong evidence for the presence of an KCa3.1 channel on the RER membrane in rat brain, exhibiting distinct electro-pharmacological profile compared to plasma membrane and other organelles.
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Affiliation(s)
- Javad Fahanik-Babaei
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Bagheri
- Department of Physiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Sajjad Salari
- Department of Physiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran.
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Brunetti V, Berra-Romani R, Conca F, Soda T, Biella GR, Gerbino A, Moccia F, Scarpellino G. Lysosomal TRPML1 triggers global Ca 2+ signals and nitric oxide release in human cerebrovascular endothelial cells. Front Physiol 2024; 15:1426783. [PMID: 38974517 PMCID: PMC11224436 DOI: 10.3389/fphys.2024.1426783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 06/03/2024] [Indexed: 07/09/2024] Open
Abstract
Lysosomal Ca2+ signaling is emerging as a crucial regulator of endothelial Ca2+ dynamics. Ca2+ release from the acidic vesicles in response to extracellular stimulation is usually promoted via Two Pore Channels (TPCs) and is amplified by endoplasmic reticulum (ER)-embedded inositol-1,3,4-trisphosphate (InsP3) receptors and ryanodine receptors. Emerging evidence suggests that sub-cellular Ca2+ signals in vascular endothelial cells can also be generated by the Transient Receptor Potential Mucolipin 1 channel (TRPML1) channel, which controls vesicle trafficking, autophagy and gene expression. Herein, we adopted a multidisciplinary approach, including live cell imaging, pharmacological manipulation, and gene targeting, revealing that TRPML1 protein is expressed and triggers global Ca2+ signals in the human brain microvascular endothelial cell line, hCMEC/D3. The direct stimulation of TRPML1 with both the synthetic agonist, ML-SA1, and the endogenous ligand phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) induced a significant increase in [Ca2+]i, that was reduced by pharmacological blockade and genetic silencing of TRPML1. In addition, TRPML1-mediated lysosomal Ca2+ release was sustained both by lysosomal Ca2+ release and ER Ca2+- release through inositol-1,4,5-trisphophate receptors and store-operated Ca2+ entry. Notably, interfering with TRPML1-mediated lysosomal Ca2+ mobilization led to a decrease in the free ER Ca2+ concentration. Imaging of DAF-FM fluorescence revealed that TRPML1 stimulation could also induce a significant Ca2+-dependent increase in nitric oxide concentration. Finally, the pharmacological and genetic blockade of TRPML1 impaired ATP-induced intracellular Ca2+ release and NO production. These findings, therefore, shed novel light on the mechanisms whereby the lysosomal Ca2+ store can shape endothelial Ca2+ signaling and Ca2+-dependent functions in vascular endothelial cells.
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Affiliation(s)
- Valentina Brunetti
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Pavia, Italy
| | - Roberto Berra-Romani
- Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Filippo Conca
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, Padova, Italy
| | - Teresa Soda
- Department of Health Sciences, University of Magna Graecia, Catanzaro, Italy
| | - Gerardo Rosario Biella
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Pavia, Italy
| | - Andrea Gerbino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari “Aldo Moro”, Bari, Italy
| | - Francesco Moccia
- Department of Medicine and Health Sciences “V. Tiberio”, University of Molise, Campobasso, Italy
| | - Giorgia Scarpellino
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, Pavia, Italy
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Brunetti V, Soda T, Berra-Romani R, De Sarro G, Guerra G, Scarpellino G, Moccia F. Two Signaling Modes Are Better than One: Flux-Independent Signaling by Ionotropic Glutamate Receptors Is Coming of Age. Biomedicines 2024; 12:880. [PMID: 38672234 PMCID: PMC11048239 DOI: 10.3390/biomedicines12040880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/02/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the central nervous system. Glutamatergic transmission can be mediated by ionotropic glutamate receptors (iGluRs), which mediate rapid synaptic depolarization that can be associated with Ca2+ entry and activity-dependent change in the strength of synaptic transmission, as well as by metabotropic glutamate receptors (mGluRs), which mediate slower postsynaptic responses through the recruitment of second messenger systems. A wealth of evidence reported over the last three decades has shown that this dogmatic subdivision between iGluRs and mGluRs may not reflect the actual physiological signaling mode of the iGluRs, i.e., α-amino-3-hydroxy-5-methyl-4-isoxasolepropionic acid (AMPA) receptors (AMPAR), kainate receptors (KARs), and N-methyl-D-aspartate (NMDA) receptors (NMDARs). Herein, we review the evidence available supporting the notion that the canonical iGluRs can recruit flux-independent signaling pathways not only in neurons, but also in brain astrocytes and cerebrovascular endothelial cells. Understanding the signaling versatility of iGluRs can exert a profound impact on our understanding of glutamatergic synapses. Furthermore, it may shed light on novel neuroprotective strategies against brain disorders.
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Affiliation(s)
- Valentina Brunetti
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, 27110 Pavia, Italy; (V.B.); (G.S.)
| | - Teresa Soda
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (T.S.); (G.D.S.)
| | - Roberto Berra-Romani
- Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico;
| | - Giovambattista De Sarro
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (T.S.); (G.D.S.)
- System and Applied Pharmacology@University Magna Grecia, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, 88110 Catanzaro, Italy
| | - Germano Guerra
- Department of Medicine and Health Science “Vincenzo Tiberio”, School of Medicine and Surgery, University of Molise, 86100 Campobasso, Italy;
| | - Giorgia Scarpellino
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, 27110 Pavia, Italy; (V.B.); (G.S.)
| | - Francesco Moccia
- Department of Medicine and Health Science “Vincenzo Tiberio”, School of Medicine and Surgery, University of Molise, 86100 Campobasso, Italy;
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Servín Muñoz IV, Ortuño-Sahagún D, Griñán-Ferré C, Pallàs M, González-Castillo C. Alterations in Proteostasis Mechanisms in Niemann-Pick Type C Disease. Int J Mol Sci 2024; 25:3806. [PMID: 38612616 PMCID: PMC11011983 DOI: 10.3390/ijms25073806] [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: 02/01/2024] [Revised: 02/20/2024] [Accepted: 02/26/2024] [Indexed: 04/14/2024] Open
Abstract
Niemann-Pick Type C (NPC) represents an autosomal recessive disorder with an incidence rate of 1 in 150,000 live births, classified within lysosomal storage diseases (LSDs). The abnormal accumulation of unesterified cholesterol characterizes the pathophysiology of NPC. This phenomenon is not unique to NPC, as analogous accumulations have also been observed in Alzheimer's disease, Parkinson's disease, and other neurodegenerative disorders. Interestingly, disturbances in the folding of the mutant protein NPC1 I1061T are accompanied by the aggregation of proteins such as hyperphosphorylated tau, α-synuclein, TDP-43, and β-amyloid peptide. These accumulations suggest potential disruptions in proteostasis, a regulatory process encompassing four principal mechanisms: synthesis, folding, maintenance of folding, and protein degradation. The dysregulation of these processes leads to excessive accumulation of abnormal proteins that impair cell function and trigger cytotoxicity. This comprehensive review delineates reported alterations across proteostasis mechanisms in NPC, encompassing changes in processes from synthesis to degradation. Additionally, it discusses therapeutic interventions targeting pharmacological facets of proteostasis in NPC. Noteworthy among these interventions is valproic acid, a histone deacetylase inhibitor (HDACi) that modulates acetylation during NPC1 synthesis. In addition, various therapeutic options addressing protein folding modulation, such as abiraterone acetate, DHBP, calnexin, and arimoclomol, are examined. Additionally, treatments impeding NPC1 degradation, exemplified by bortezomib and MG132, are explored as potential strategies. This review consolidates current knowledge on proteostasis dysregulation in NPC and underscores the therapeutic landscape targeting diverse facets of this intricate process.
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Affiliation(s)
- Iris Valeria Servín Muñoz
- Laboratorio de Neuroinmunobiología Molecular, Instituto de Investigación en Ciencias Biomédicas (IICB), Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara 44340, Mexico;
| | - Daniel Ortuño-Sahagún
- Laboratorio de Neuroinmunobiología Molecular, Instituto de Investigación en Ciencias Biomédicas (IICB), Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara 44340, Mexico;
| | - Christian Griñán-Ferré
- Pharmacology Section, Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, Institute of Neuroscience, Universitat de Barcelona, 08028 Barcelona, Spain; (C.G.-F.); (M.P.)
- Centro de Investigación Biomédica en Red (CiberNed), Network Center for Neurodegenerative Diseases, National Spanish Health Institute Carlos III, 28220 Madrid, Spain
| | - Mercè Pallàs
- Pharmacology Section, Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Sciences, Institute of Neuroscience, Universitat de Barcelona, 08028 Barcelona, Spain; (C.G.-F.); (M.P.)
- Centro de Investigación Biomédica en Red (CiberNed), Network Center for Neurodegenerative Diseases, National Spanish Health Institute Carlos III, 28220 Madrid, Spain
| | - Celia González-Castillo
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Campus Guadalajara, Zapopan 45201, Mexico
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Song SE, Shin SK, Ju HY, Im SS, Song DK. Role of cytosolic and endoplasmic reticulum Ca 2+ in pancreatic beta-cells: pros and cons. Pflugers Arch 2024; 476:151-161. [PMID: 37940681 DOI: 10.1007/s00424-023-02872-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/18/2023] [Accepted: 10/25/2023] [Indexed: 11/10/2023]
Abstract
Pancreatic beta cells utilize Ca2+ to secrete insulin in response to glucose. The glucose-dependent increase in cytosolic Ca2+ concentration ([Ca2+]C) activates a series of insulin secretory machinery in pancreatic beta cells. Therefore, the amount of insulin secreted in response to glucose is determined in a [Ca2+]C-dependent manner, at least within a moderate range. However, the demand for insulin secretion may surpass the capability of beta cells. Abnormal elevation of [Ca2+]C levels beyond the beta-cell endurance capacity can damage them by inducing endoplasmic reticulum (ER) stress and cell death programs such as apoptosis. Therefore, while Ca2+ is essential for the insulin secretory functions of beta cells, it could affect their survival at pathologically higher levels. Because an increase in beta-cell [Ca2+]C is inevitable under certain hazardous conditions, understanding the regulatory mechanism for [Ca2+]C is important. Therefore, this review discusses beta-cell function, survival, ER stress, and apoptosis associated with intracellular and ER Ca2+ homeostasis.
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Affiliation(s)
- Seung-Eun Song
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Su-Kyung Shin
- Department of Food Science and Nutrition, Kyungpook National University, Daegu, South Korea
| | - Hyeon Yeong Ju
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Seung-Soon Im
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea
| | - Dae-Kyu Song
- Department of Physiology & Obesity-Mediated Disease Research Center, Keimyung University School of Medicine, 1095 Dalgubeol-Daeroro, Dalseo-Gu, Daegu, 42601, South Korea.
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Moccia F, Brunetti V, Soda T, Berra-Romani R, Scarpellino G. Cracking the Endothelial Calcium (Ca 2+) Code: A Matter of Timing and Spacing. Int J Mol Sci 2023; 24:16765. [PMID: 38069089 PMCID: PMC10706333 DOI: 10.3390/ijms242316765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/16/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
A monolayer of endothelial cells lines the innermost surface of all blood vessels, thereby coming into close contact with every region of the body and perceiving signals deriving from both the bloodstream and parenchymal tissues. An increase in intracellular Ca2+ concentration ([Ca2+]i) is the main mechanism whereby vascular endothelial cells integrate the information conveyed by local and circulating cues. Herein, we describe the dynamics and spatial distribution of endothelial Ca2+ signals to understand how an array of spatially restricted (at both the subcellular and cellular levels) Ca2+ signals is exploited by the vascular intima to fulfill this complex task. We then illustrate how local endothelial Ca2+ signals affect the most appropriate vascular function and are integrated to transmit this information to more distant sites to maintain cardiovascular homeostasis. Vasorelaxation and sprouting angiogenesis were selected as an example of functions that are finely tuned by the variable spatio-temporal profile endothelial Ca2+ signals. We further highlighted how distinct Ca2+ signatures regulate the different phases of vasculogenesis, i.e., proliferation and migration, in circulating endothelial precursors.
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Affiliation(s)
- Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (V.B.); (G.S.)
| | - Valentina Brunetti
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (V.B.); (G.S.)
| | - Teresa Soda
- Department of Health Sciences, University of Magna Graecia, 88100 Catanzaro, Italy;
| | - Roberto Berra-Romani
- Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico;
| | - Giorgia Scarpellino
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (V.B.); (G.S.)
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