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Hawlina S, Zorec R, Chowdhury HH. Potential of Personalized Dendritic Cell-Based Immunohybridoma Vaccines to Treat Prostate Cancer. Life (Basel) 2023; 13:1498. [PMID: 37511873 PMCID: PMC10382052 DOI: 10.3390/life13071498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
Prostate cancer (PCa) is the most commonly diagnosed cancer and the second most common cause of death due to cancer. About 30% of patients with PCa who have been castrated develop a castration-resistant form of the disease (CRPC), which is incurable. In the last decade, new treatments that control the disease have emerged, slowing progression and spread and prolonging survival while maintaining the quality of life. These include immunotherapies; however, we do not yet know the optimal combination and sequence of these therapies with the standard ones. All therapies are not always suitable for every patient due to co-morbidities or adverse effects of therapies or both, so there is an urgent need for further work on new therapeutic options. Advances in cancer immunotherapy with an immune checkpoint inhibition mechanism (e.g., ipilimumab, an anti-CTLA-4 inhibitor) have not shown a survival benefit in patients with CRPC. Other immunological approaches have also not given clear results, which has indirectly prevented breakthrough for this type of therapeutic strategy into clinical use. Currently, the only approved form of immunotherapy for patients with CRPC is a cell-based medicine, but it is only available to patients in some parts of the world. Based on what was gained from recently completed clinical research on immunotherapy with dendritic cell-based immunohybridomas, the aHyC dendritic cell vaccine for patients with CRPC, we highlight the current status and possible alternatives that should be considered in the future.
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Affiliation(s)
- Simon Hawlina
- Clinical Department of Urology, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia
- Department of Surgery, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Helena H Chowdhury
- Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
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2
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Hawlina S, Chowdhury HH, Smrkolj T, Zorec R. Dendritic cell-based vaccine prolongs survival and time to next therapy independently of the vaccine cell number. Biol Direct 2022; 17:5. [PMID: 35197090 PMCID: PMC8864901 DOI: 10.1186/s13062-022-00318-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 12/15/2021] [Indexed: 11/10/2022] Open
Abstract
In 2009, new EU legislation regulating advanced therapy medicinal products (ATMPs), consisting of gene therapy, tissue engineering and cell-based medicines, was introduced. Although less than 20 ATMPs were authorized since that time, the awarding of the Nobel Prize for Physiology or Medicine in 2018 revived interest in developing new cancer immunotherapies involving significant manipulation of the patient's own immune cells, including lymphocytes and dendritic cells. The lymphocytes are mainly thought to directly affect tumour cells, dendritic cells are involved in indirect mechanisms by antigen presentation to other leukocytes orchestrating the immune response. It is the latter cells that are the focus of this brief review. Based on the recent results of our study treating patients with castration-resistant prostate cancer (CRPC) with an immunohybridoma cell construct (termed aHyC), produced by electrofusion of autologous tumour and dendritic cells, we compare their effectiveness with a matched documented control group of patients. The results revealed that cancer-specific survival and the time to next in-line therapy (TTNT) were both significantly prolonged versus controls. When patients were observed for longer periods since the time of diagnosis of CRPC, 20% of patients had not yet progressed to the next in-line therapy even though the time under observation was ~ 80 months. Interestingly, analysis of survival of patients revealed that the effectiveness of treatment was independent of the number of cells in the vaccine used for treatment. It is concluded that autologous dendritic cell-based immunotherapy is a new possibility to treat not only CRPC but also other solid tumours.
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Affiliation(s)
- Simon Hawlina
- Clinical Department of Urology, University Medical Centre Ljubljana, 1000, Ljubljana, Slovenia.,Department of Surgery, Faculty of Medicine, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Helena H Chowdhury
- Laboratory of Cell Engineering, Celica Biomedical, 1000, Ljubljana, Slovenia.,Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000, Ljubljana, Slovenia
| | - Tomaž Smrkolj
- Clinical Department of Urology, University Medical Centre Ljubljana, 1000, Ljubljana, Slovenia.,Department of Surgery, Faculty of Medicine, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Cell Engineering, Celica Biomedical, 1000, Ljubljana, Slovenia. .,Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000, Ljubljana, Slovenia.
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3
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D'Adamo P, Horvat A, Gurgone A, Mignogna ML, Bianchi V, Masetti M, Ripamonti M, Taverna S, Velebit J, Malnar M, Muhič M, Fink K, Bachi A, Restuccia U, Belloli S, Moresco RM, Mercalli A, Piemonti L, Potokar M, Bobnar ST, Kreft M, Chowdhury HH, Stenovec M, Vardjan N, Zorec R. Inhibiting glycolysis rescues memory impairment in an intellectual disability Gdi1-null mouse. Metabolism 2021; 116:154463. [PMID: 33309713 PMCID: PMC7871014 DOI: 10.1016/j.metabol.2020.154463] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/30/2020] [Accepted: 12/04/2020] [Indexed: 01/08/2023]
Abstract
OBJECTIVES GDI1 gene encodes for αGDI, a protein controlling the cycling of small GTPases, reputed to orchestrate vesicle trafficking. Mutations in human GDI1 are responsible for intellectual disability (ID). In mice with ablated Gdi1, a model of ID, impaired working and associative short-term memory was recorded. This cognitive phenotype worsens if the deletion of αGDI expression is restricted to neurons. However, whether astrocytes, key homeostasis providing neuroglial cells, supporting neurons via aerobic glycolysis, contribute to this cognitive impairment is unclear. METHODS We carried out proteomic analysis and monitored [18F]-fluoro-2-deoxy-d-glucose uptake into brain slices of Gdi1 knockout and wild type control mice. d-Glucose utilization at single astrocyte level was measured by the Förster Resonance Energy Transfer (FRET)-based measurements of cytosolic cyclic AMP, d-glucose and L-lactate, evoked by agonists selective for noradrenaline and L-lactate receptors. To test the role of astrocyte-resident processes in disease phenotype, we generated an inducible Gdi1 knockout mouse carrying the Gdi1 deletion only in adult astrocytes and conducted behavioural tests. RESULTS Proteomic analysis revealed significant changes in astrocyte-resident glycolytic enzymes. Imaging [18F]-fluoro-2-deoxy-d-glucose revealed an increased d-glucose uptake in Gdi1 knockout tissue versus wild type control mice, consistent with the facilitated d-glucose uptake determined by FRET measurements. In mice with Gdi1 deletion restricted to astrocytes, a selective and significant impairment in working memory was recorded, which was rescued by inhibiting glycolysis by 2-deoxy-d-glucose injection. CONCLUSIONS These results reveal a new astrocyte-based mechanism in neurodevelopmental disorders and open a novel therapeutic opportunity of targeting aerobic glycolysis, advocating a change in clinical practice.
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Affiliation(s)
- Patrizia D'Adamo
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy; University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia.
| | - Anemari Horvat
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia
| | - Antonia Gurgone
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Veronica Bianchi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Michela Masetti
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maddalena Ripamonti
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Stefano Taverna
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Jelena Velebit
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia
| | - Maja Malnar
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia
| | - Marko Muhič
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia
| | - Katja Fink
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia
| | - Angela Bachi
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | | | - Sara Belloli
- Institute of Bioimaging and Physiology, CNR, Segrate (MI), Italy; Experimental Imaging Center (EIC), San Raffaele Scientific Institute, Milan, Italy
| | - Rosa Maria Moresco
- Experimental Imaging Center (EIC), San Raffaele Scientific Institute, Milan, Italy; Medicine and Surgery Department, University of Milano-Bicocca, Monza (MB), Italy
| | - Alessia Mercalli
- Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Lorenzo Piemonti
- Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milano, Italy; Università Vita-Salute San Raffaele, Milano, Italy
| | - Maja Potokar
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia
| | - Saša Trkov Bobnar
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia
| | - Marko Kreft
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia; University of Ljubljana, Biotechnical Faculty, Department of Biology, Ljubljana, Slovenia
| | - Helena H Chowdhury
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia
| | - Matjaž Stenovec
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia
| | - Nina Vardjan
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia.
| | - Robert Zorec
- University of Ljubljana, Faculty of Medicine, Institute of Pathophysiology, Laboratory of Neuroendocrinology - Molecular Cell Physiology, Ljubljana, Slovenia; Celica Biomedical, Laboratory for Cell Engineering, Ljubljana, Slovenia.
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Chowdhury HH. Differences in cytosolic glucose dynamics in astrocytes and adipocytes measured by FRET-based nanosensors. Biophys Chem 2020; 261:106377. [PMID: 32302866 DOI: 10.1016/j.bpc.2020.106377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 11/17/2022]
Abstract
The cellular response to fluctuations in blood glucose levels consists of integrative regulation of cell glucose uptake and glucose utilization in the cytosol, resulting in altered levels of glucose in the cytosol. Cytosolic glucose is difficult to be measured in the intact tissue, however recently methods have become available that allow measurements of glucose in single living cells with fluorescence resonance energy transfer (FRET) based protein sensors. By studying the dynamics of cytosolic glucose levels in different experimental settings, we can gain insights into the properties of plasma membrane permeability to glucose and glucose utilization in the cytosol, and how these processes are modulated by different environmental conditions, agents and enzymes. In this review, we compare the cytosolic regulation of glucose in adipocytes and astrocytes - two important regulators of energy balance and glucose homeostasis in whole body and brain, respectively, with particular emphasis on the data obtained with FRET based protein sensors as well as other biochemical and molecular approaches.
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Affiliation(s)
- Helena H Chowdhury
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, 1000 Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia.
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5
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Vardjan N, Chowdhury HH, Horvat A, Velebit J, Malnar M, Muhič M, Kreft M, Krivec ŠG, Bobnar ST, Miš K, Pirkmajer S, Offermanns S, Henriksen G, Storm-Mathisen J, Bergersen LH, Zorec R. Enhancement of Astroglial Aerobic Glycolysis by Extracellular Lactate-Mediated Increase in cAMP. Front Mol Neurosci 2018; 11:148. [PMID: 29867342 PMCID: PMC5953330 DOI: 10.3389/fnmol.2018.00148] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/16/2018] [Indexed: 11/13/2022] Open
Abstract
Besides being a neuronal fuel, L-lactate is also a signal in the brain. Whether extracellular L-lactate affects brain metabolism, in particular astrocytes, abundant neuroglial cells, which produce L-lactate in aerobic glycolysis, is unclear. Recent studies suggested that astrocytes express low levels of the L-lactate GPR81 receptor (EC50 ≈ 5 mM) that is in fat cells part of an autocrine loop, in which the Gi-protein mediates reduction of cytosolic cyclic adenosine monophosphate (cAMP). To study whether a similar signaling loop is present in astrocytes, affecting aerobic glycolysis, we measured the cytosolic levels of cAMP, D-glucose and L-lactate in single astrocytes using fluorescence resonance energy transfer (FRET)-based nanosensors. In contrast to the situation in fat cells, stimulation by extracellular L-lactate and the selective GPR81 agonists, 3-chloro-5-hydroxybenzoic acid (3Cl-5OH-BA) or 4-methyl-N-(5-(2-(4-methylpiperazin-1-yl)-2-oxoethyl)-4-(2-thienyl)-1,3-thiazol-2-yl)cyclohexanecarboxamide (Compound 2), like adrenergic stimulation, elevated intracellular cAMP and L-lactate in astrocytes, which was reduced by the inhibition of adenylate cyclase. Surprisingly, 3Cl-5OH-BA and Compound 2 increased cytosolic cAMP also in GPR81-knock out astrocytes, indicating that the effect is GPR81-independent and mediated by a novel, yet unidentified, excitatory L-lactate receptor-like mechanism in astrocytes that enhances aerobic glycolysis and L-lactate production via a positive feedback mechanism.
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Affiliation(s)
- Nina Vardjan
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
| | - Helena H Chowdhury
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
| | - Anemari Horvat
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jelena Velebit
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
| | - Maja Malnar
- Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
| | - Marko Muhič
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Marko Kreft
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia.,Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Špela G Krivec
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
| | - Saša T Bobnar
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
| | - Katarina Miš
- Laboratory for Molecular Neurobiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Sergej Pirkmajer
- Laboratory for Molecular Neurobiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Gjermund Henriksen
- Nuclear and Energy Physics, Department of Physics, The Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.,Norwegian Medical Cyclotron Centre Ltd., Oslo, Norway
| | - Jon Storm-Mathisen
- Division of Anatomy, Department of Molecular Medicine, CMBN/SERTA Healthy Brain Ageing Centre, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Linda H Bergersen
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway.,Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Robert Zorec
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
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Chowdhury HH, Cerqueira SR, Sousa N, Oliveira JM, Reis RL, Zorec R. The uptake, retention and clearance of drug-loaded dendrimer nanoparticles in astrocytes – electrophysiological quantification. Biomater Sci 2018; 6:388-397. [DOI: 10.1039/c7bm00886d] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Endocytosed dendrimer nanoparticles (NPs) are cleared from the astrocytes by an increased rate of transient exocytotic fusion events.
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Affiliation(s)
- Helena H. Chowdhury
- Laboratory of Neuroendocrinology – Molecular Cell Physiology
- Institute of Pathophysiology
- Faculty of Medicine
- 1000 Ljubljana
- Slovenia
| | - Susana R. Cerqueira
- 3B's Research Group – Biomaterials
- Biodegradables and Biomimetics
- University of Minho
- Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine
- 4805-017 Barco GMR
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS)
- School of Health Sciences
- University of Minho
- 4710-057 Braga
- Portugal
| | - Joaquim M. Oliveira
- 3B's Research Group – Biomaterials
- Biodegradables and Biomimetics
- University of Minho
- Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine
- 4805-017 Barco GMR
| | - Rui L. Reis
- 3B's Research Group – Biomaterials
- Biodegradables and Biomimetics
- University of Minho
- Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine
- 4805-017 Barco GMR
| | - Robert Zorec
- Laboratory of Neuroendocrinology – Molecular Cell Physiology
- Institute of Pathophysiology
- Faculty of Medicine
- 1000 Ljubljana
- Slovenia
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Chowdhury HH, Velebit J, Mekjavic IB, Eiken O, Kreft M, Zorec R. Systemic Hypoxia Increases the Expression of DPP4 in Preadipocytes of Healthy Human Participants. Exp Clin Endocrinol Diabetes 2017; 126:91-95. [PMID: 28950392 DOI: 10.1055/s-0043-113451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Dipeptidyl peptidase 4 (DPP4) is a transmembrane glycoprotein involved in protein degradation. Due to its action on incretins, which increase insulin secretion, DPP4 is considered a therapeutic target for type 2 diabetes. Here we have studied the role of single and combined effects of hypoxia and inactivity on the expression of DPP4 in human adipose tissue of 12 adult normal-weight males. Fat biopsies were obtained at baseline and after each of three experimental campaigns. The results revealed that in isolated human preadipocytes the expression of DPP4 was significantly increased by exposure of participants to hypoxia. Physical inactivity per se had no apparent effect on the DPP4 expression. It is concluded that DPP4 may be a marker to monitor indirectly tissue hypoxia, as occurs in obese subjects.
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Affiliation(s)
- Helena H Chowdhury
- Laboratory for Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana, Slovenia.,Celica Biomedical, Tehnološki park 24, Ljubljana, Slovenia
| | - Jelena Velebit
- Laboratory for Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana, Slovenia.,Celica Biomedical, Tehnološki park 24, Ljubljana, Slovenia
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Jamova 39, Ljubljana, Slovenia
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden
| | - Marko Kreft
- Laboratory for Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana, Slovenia.,Celica Biomedical, Tehnološki park 24, Ljubljana, Slovenia.,Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory for Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana, Slovenia.,Celica Biomedical, Tehnološki park 24, Ljubljana, Slovenia
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8
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Chowdhury HH, Velebit J, Radić N, Frančič V, Kreft M, Zorec R. Hypoxia Alters the Expression of Dipeptidyl Peptidase 4 and Induces Developmental Remodeling of Human Preadipocytes. J Diabetes Res 2016; 2016:7481470. [PMID: 26881257 PMCID: PMC4735901 DOI: 10.1155/2016/7481470] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/25/2015] [Indexed: 01/25/2023] Open
Abstract
Dipeptidyl peptidase 4 (DPP4), a transmembrane protein, has been identified in human adipose tissue and is considered to be associated with obesity-related type 2 diabetes. Since adipose tissue is relatively hypoxic in obese participants, we investigated the expression of DPP4 in human preadipocytes (hPA) and adipocytes in hypoxia, during differentiation and upon insulin stimulation. The results show that DPP4 is abundantly expressed in hPA but very sparsely in adipocytes. During differentiation in vitro, the expression of DPP4 in hPA is reduced on the addition of differentiation medium, indicating that this protein can be hPA marker. Long term hypoxia altered the expression of DPP4 in hPA. In in vitro hypoxic conditions the protease activity of shed DPP4 is reduced; however, in the presence of insulin, the increase in DPP4 expression is potentiated by hypoxia.
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Affiliation(s)
- Helena H. Chowdhury
- Laboratory for Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
- Celica Biomedical Center, Tehnološki Park 24, SI-1000 Ljubljana, Slovenia
| | - Jelena Velebit
- Laboratory for Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
- Celica Biomedical Center, Tehnološki Park 24, SI-1000 Ljubljana, Slovenia
| | - Nataša Radić
- Laboratory for Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
- Celica Biomedical Center, Tehnološki Park 24, SI-1000 Ljubljana, Slovenia
| | - Vito Frančič
- Celica Biomedical Center, Tehnološki Park 24, SI-1000 Ljubljana, Slovenia
| | - Marko Kreft
- Laboratory for Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
- Celica Biomedical Center, Tehnološki Park 24, SI-1000 Ljubljana, Slovenia
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory for Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
- Celica Biomedical Center, Tehnološki Park 24, SI-1000 Ljubljana, Slovenia
- *Robert Zorec:
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Muhič M, Vardjan N, Chowdhury HH, Zorec R, Kreft M. Insulin and Insulin-like Growth Factor 1 (IGF-1) Modulate Cytoplasmic Glucose and Glycogen Levels but Not Glucose Transport across the Membrane in Astrocytes. J Biol Chem 2015; 290:11167-76. [PMID: 25792745 DOI: 10.1074/jbc.m114.629063] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 01/21/2023] Open
Abstract
Astrocytes contain glycogen, an energy buffer, which can bridge local short term energy requirements in the brain. Glycogen levels reflect a dynamic equilibrium between glycogen synthesis and glycogenolysis. Many factors that include hormones and neuropeptides, such as insulin and insulin-like growth factor 1 (IGF-1) likely modulate glycogen stores in astrocytes, but detailed mechanisms at the cellular level are sparse. We used a glucose nanosensor based on Förster resonance energy transfer to monitor cytosolic glucose concentration with high temporal resolution and a cytochemical approach to determine glycogen stores in single cells. The results show that after glucose depletion, glycogen stores are replenished. Insulin and IGF-1 boost the process of glycogen formation. Although astrocytes appear to express glucose transporter GLUT4, glucose entry across the astrocyte plasma membrane is not affected by insulin. Stimulation of cells with insulin and IGF-1 decreased cytosolic glucose concentration, likely because of elevated glucose utilization for glycogen synthesis.
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Affiliation(s)
- Marko Muhič
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
| | - Nina Vardjan
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia, Celica Biomedical, 1000 Ljubljana, Slovenia, and
| | - Helena H Chowdhury
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia, Celica Biomedical, 1000 Ljubljana, Slovenia, and
| | - Robert Zorec
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia, Celica Biomedical, 1000 Ljubljana, Slovenia, and
| | - Marko Kreft
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia, Celica Biomedical, 1000 Ljubljana, Slovenia, and the Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
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Rituper B, Flašker A, Guček A, Chowdhury HH, Zorec R. Cholesterol and regulated exocytosis: A requirement for unitary exocytotic events. Cell Calcium 2012; 52:250-8. [DOI: 10.1016/j.ceca.2012.05.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 05/07/2012] [Accepted: 05/15/2012] [Indexed: 11/30/2022]
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Abstract
The adipocyte enlargement is associated with an increase in the cytoplasmic lipid content, but how the plasma membrane area follows this increase is poorly understood. We monitored single-cell membrane surface area fluctuations, which mirror the dynamics of exocytosis and endocytosis. We employed the patch-clamp technique to measure membrane capacitance (C(m)), a parameter linearly related to the plasma membrane area. Specifically, we studied whether insulin affects membrane area dynamics in adipocytes. A five-minute cell exposure to insulin increased resting C(m) by 12 ± 4%; in controls the change in C(m) was not different from zero. We measured cell diameter of isolated rat adipocytes microscopically. Twenty-four hour exposure of cells to insulin resulted in a significant increase in cell diameter by 5.1 ± 0.6%. We conclude that insulin induces membrane area increase, which may in chronic hyperinsulinemia promote the enlargement of plasma membrane area, acting in concert with other insulin-mediated metabolic effects on adipocytes.
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Affiliation(s)
- H H Chowdhury
- Laboratory of Neuroendocrinology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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12
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Potokar M, Lacovich V, Chowdhury HH, Kreft M, Zorec R. Rab4 and Rab5 GTPase are required for directional mobility of endocytic vesicles in astrocytes. Glia 2012; 60:594-604. [PMID: 22279005 DOI: 10.1002/glia.22293] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 12/16/2011] [Indexed: 11/07/2022]
Abstract
Rab4 and Rab5 GTPases are key players in the regulation of endocytosis. Although their role has been studied intensively in the past, it is still unclear how they regulate vesicle mobility. In particular, in astrocytes, the most abundant glial cells in the brain, vesicles have been shown to exhibit nondirectional and directional mobility, which can be intermittent, but the underlying switching mechanisms are not known. By using quantitative imaging, we studied the dynamics of single vesicle movements in astrocytes in real time, by transfecting them with different GDP- and GTP-locked mutants of Rab4 and Rab5. Along with the localization of Rab4 and Rab5 on early and late endocytic compartments, we measured the apparent vesicle size by monitoring the area of fluorescent puncta and determined the patterns of vesicle mobility in the presence of wild-type and Rab mutants. Dominant-negative and dominant-positive mutants, Rab4 S22N, Rab5 S34N and Rab4 Q67L, Rab5 Q79L, induced an increase in the apparent vesicle size, especially Rab5 mutants. These mutants also significantly reduced vesicle mobility in terms of vesicle track length, maximal displacement, and speed. In addition, significant reductions in the fraction of vesicles exhibiting directional mobility were observed in cells expressing Rab4 S22N, Rab4 Q67L, Rab5 S34N, and Rab5 Q79L. Our data indicate that changes in the GDP-GTP switch apparently not only affect fusion events in endocytosis and recycling, as already proposed, but also affect the molecular interactions determining directional vesicle mobility, likely involving motor proteins and the cytoskeleton.
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Affiliation(s)
- Maja Potokar
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
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13
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Kovacic PB, Chowdhury HH, Velebit J, Kreft M, Jensen J, Zorec R. New insights into cytosolic glucose levels during differentiation of 3T3-L1 fibroblasts into adipocytes. J Biol Chem 2011; 286:13370-81. [PMID: 21349852 DOI: 10.1074/jbc.m110.200980] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytosolic glucose concentration reflects the balance between glucose entry across the plasma membrane and cytosolic glucose utilization. In adipocytes, glucose utilization is considered very rapid, meaning that every glucose molecule entering the cytoplasm is quickly phosphorylated. Thus, the cytosolic free glucose concentration is considered to be negligible; however, it was never measured directly. In the present study, we monitored cytosolic glucose dynamics in 3T3-L1 fibroblasts and adipocytes by expressing a fluorescence resonance energy transfer (FRET)-based glucose nanosensor: fluorescent indicator protein FLIPglu-600μ. Specifically, we monitored cytosolic glucose responses by varying transmembrane glucose concentration gradient. The changes in cytosolic glucose concentration were detected in only 56% of 3T3-L1 fibroblasts and in 14% of 3T3-L1 adipocytes. In adipocytes, the resting cytosolic glucose concentration was reduced in comparison with the one recorded in fibroblasts. Membrane permeabilization increased cytosolic glucose concentration in adipocytes, and glycolytic inhibitor iodoacetate failed to increase cytosolic glucose concentration, indicating low adipocyte permeability for glucose at rest. We also examined the effects of insulin and adrenaline. Insulin significantly increased cytosolic glucose concentration in adipocytes by a factor of 3.6; however, we recorded no effect on delta ratio (ΔR) in fibroblasts. Adrenaline increased cytosolic glucose concentration in fibroblasts but not in adipocytes. However, in adipocytes in insulin-stimulated conditions, glucose clearance was significantly faster following adrenaline addition in comparison with controls (p < 0.001). Together, these results demonstrate that during differentiation, adipocytes develop more efficient mechanisms for maintaining low cytosolic glucose concentration, predominantly with reduced membrane permeability for glucose.
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14
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Velebit J, Chowdhury HH, Kreft M, Zorec R. Rosiglitazone balances insulin-induced exo- and endocytosis in single 3T3-L1 adipocytes. Mol Cell Endocrinol 2011; 333:70-7. [PMID: 21167254 DOI: 10.1016/j.mce.2010.12.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 12/06/2010] [Accepted: 12/07/2010] [Indexed: 11/20/2022]
Abstract
Rosiglitazone (Rosi) improves insulin sensitivity and increases the translocation of glucose transporter 4 (GLUT4) to the plasma membrane (PM). This involves the fusion of membrane-bound compartments with the plasma membrane, thus increasing the plasma membrane area. However, recent work has shown that in Rosi-pretreated 3T3-L1 adipocytes membrane area did not increase following insulin application, suggesting that the rates of exo- and endocytosis are balanced. Here we examined whether Rosi differentially affects the rates of exo- and endocytosis in 3T3-L1 adipocytes. The immunolabelling of GLUT4 revealed the 3.1-fold increase in PM-resident GLUT4 in Rosi-pretreated, insulin-stimulated cells. By monitoring cumulative exocytosis and endocytosis we found that in Rosi-pretreated cells insulin substantially stimulated the rate of exocytosis and to a similar extent also the rate of endocytosis. We conclude that Rosi-pretreatment balances insulin-stimulated exocytosis and endocytosis, which may prevent insulin-mediated adipocyte cell size increase.
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Kreft M, Prebil M, Chowdhury HH, Grilc S, Jensen J, Zorec R. Analysis of confocal images using variable-width line profiles. Protoplasma 2010; 246:73-80. [PMID: 20229327 DOI: 10.1007/s00709-010-0127-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 02/19/2010] [Indexed: 05/28/2023]
Abstract
A line profile of fluorescent intensities in confocal images is frequently examined. We have developed the computer software tool to analyse the profiles of intensities of fluorescent probes in confocal images. The software averages neighbouring pixels, adjacent to the central line, without reducing the spatial resolution of the image. As an experimental model, we have used the skeletal muscle fibre isolated from the rat skeletal muscle extensor digitorum brevis. As a marker of myofibrils' structure, we have used phalloidin-rhodamine staining and the anti-TIM antibody to label mitochondria. We also tested the distribution of the protein kinase B/Akt. Since signalling is ordered in modules and large protein complexes appear to direct signalling to organelles and regulate specific physiological functions, a software tool to analyse such complexes in fluorescent confocal images is required. The software displays the image, and the user defines the line for analysis. The image is rotated by the angle of the line. The line profile is calculated by averaging one dimension of the cropped rotated image matrix. The spatial resolution in averaged line profile is not decreased compared with single-pixel line profile, which was confirmed by the discrete Fourier transform computed with a fast Fourier transform algorithm. We conclude that the custom software tool presented here is a useful tool to analyse line profiles of fluorescence intensities in confocal images.
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Affiliation(s)
- Marko Kreft
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, Ljubljana, Slovenia.
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16
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Gonçalves PP, Stenovec M, Chowdhury HH, Grilc S, Kreft M, Zorec R. Prolactin secretion sites contain syntaxin-1 and differ from ganglioside monosialic acid rafts in rat lactotrophs. Endocrinology 2008; 149:4948-57. [PMID: 18556353 DOI: 10.1210/en.2008-0096] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In neuroendocrine cells, discharge of hormones follows the fusion of exocytotic vesicles with the plasma membrane at confined sites; however, the molecular nature of these distinct sites remains poorly understood. We studied intact pituitary lactotrophs and plasma membrane lawns by confocal microscopy in conjunction with antibodies against rat prolactin (rPRL), soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE) proteins (syntaxin-1 and synaptobrevin-2,) and fluorescent cholera toxin subunit B (CT-B), a marker of ganglioside monosialic acid (GM1) lipid rafts, to examine 1) whether rPRL vesicles discharge cargo at GM1 rafts, 2) whether discharging rPRL vesicles interact with SNAREs, and 3) to examine the overlap of GM1 rafts, rPRL, and syntaxin-1 sites in plasma membrane lawns. In intact cells, immunofluorescently labeled rPRL poorly colocalized (<6%) with CT-B. In conditions favoring endocytotic trafficking, vesicle SNARE synaptobrevin-2 modestly colocalized (35%) with CT-B, whereas it highly colocalized (58%) with retrieved rPRL. Although partial mixing between rPRL and CT-B intracellular trafficking pathways is likely, our results indicated that rPRL discharge involves interactions with plasma membrane SNAREs, but not with GM1 rafts. In support of this, the plasma membrane SNARE syntaxin-1 poorly colocalized with CT-B (<5%), whereas it highly colocalized (75%) with rPRL in inside-out plasma membrane lawns. Spontaneous and stimulated rPRL discharge in live lactotrophs is thus associated with plasma membrane sites enriched with SNARE proteins, however, spatially confined to plasma membrane areas other than GM1 rafts.
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Affiliation(s)
- Paula P Gonçalves
- Centro de Estudos do Ambiente e do Mar, Departamento de Biologia, Universidade de Aveiro, Aveiro, Portugal
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17
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Velebit J, Kovacic PB, Prebil M, Chowdhury HH, Grilc S, Kreft M, Jensen J, Isenović ER, Zorec R. Rosiglitazone modulates insulin-induced plasma membrane area changes in single 3T3-L1 adipocytes. J Membr Biol 2008; 223:141-9. [PMID: 18754069 DOI: 10.1007/s00232-008-9120-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 07/08/2008] [Indexed: 11/30/2022]
Abstract
In this study we hypothesized that rosiglitazone, an antidiabetic high-affinity agonist for the peroxisome proliferator-activated receptor gamma, affects the plasma membrane (PM) turnover in single 3T3-L1 adipocytes. To study the PM turnover, the patch-clamp electrophysiological method was used to measure changes in membrane capacitance (Cm), a parameter linearly related to the PM area. Microscopy results show that the presence of rosiglitazone in the differentiating medium significantly increased the differentiation of 3T3-L1 adipocytes in cell culture, based on oil red O-stained area (11.4 +/- 1.2%) vs. controls (3.1 +/- 0.5%). Moreover, rosiglitazone treatment significantly reduced the size of single 3T3-L1 adipocytes; their average radius of 21.1 +/- 1.1 microm in controls was reduced to 17.5 +/- 0.5 microm in rosiglitazone-treated cells. Consistent with this, insulin application increased the rate of Cm increase to 2.34 +/- 0.10%/min, which was significantly different from controls (0.12 +/- 0.08%/min). However, pretreatment of cells with rosiglitazone prior to the treatment with insulin resulted in an attenuated rate of Cm increase. These data support the involvement of insulin in the modulation of membrane area and show that treatment by rosiglitazone reduced the insulin-mediated membrane area increase in 3T3-L1 adipocytes.
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Affiliation(s)
- Jelena Velebit
- Laboratory for Molecular Genetics and Radiobiology, Institute Vinca, P.O. Box 522, 11000 Belgrade, Serbia
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18
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Chowdhury HH, Rebolj K, Kreft M, Zorec R, Maček P, Sepčić K. Lysophospholipids prevent binding of a cytolytic protein ostreolysin to cholesterol-enriched membrane domains. Toxicon 2008; 51:1345-56. [DOI: 10.1016/j.toxicon.2008.03.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 02/25/2008] [Accepted: 03/03/2008] [Indexed: 10/22/2022]
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Malicev E, Chowdhury HH, Macek P, Sepcic K. Effect of ostreolysin, an Asp-hemolysin isoform, on human chondrocytes and osteoblasts, and possible role of Asp-hemolysin in pathogenesis. Med Mycol 2007; 45:123-30. [PMID: 17365648 DOI: 10.1080/13693780601039615] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Aspergillus fumigatus, a pathogenic mould causing a wide range of diseases including aspergillosis, produces a series of toxic substances which appear to act in an additive and/or synergic way on cells. Aspergillosis generally occurs in immunocompromised hosts or is associated with organ transplantation. From the muscul skeleton system the vertebrae, ribs and orbit are the most commonly affected, while the joints are less frequent targets. The cytolytic protein Asp-hemolysin is one of the toxins produced by Aspergillus fumigatus during infection. It belongs to the aegerolysin protein family and shares 43% identity in amino acid sequence with ostreolysin, a cytolysin from the mushroom Pleurotus ostreatus. In this work, ostreolysin was used in an experimental model to study the in vitro effects of aegerolysin-like proteins on human chondrocytes and osteoblasts. Immunostaining analyses showed selective binding and clustering of the protein on chondrocyte membranes, pointing to its association with distinctive membrane microdomains. Consequently, ostreolysin can induce effective permeabilization of both chondrocytes and osteoblasts. Based on sequence similarities of ostreolysin and Asp-hemolysin, their comparable cytolytic effects towards different cells, and similar signs of intoxication in experimental animals, our results indicate that Asp-hemolysin might be considered as a possible virulence factor of Aspergillus fumigatus during the infection of bone and cartilage.
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Abstract
Exocytotic vesicles in astrocytes are increasingly viewed as essential in astrocyte-to-neuron communication in the brain. In neurons and excitable secretory cells, delivery of vesicles to the plasma membrane for exocytosis involves an interaction with the cytoskeleton, in particular microtubules and actin filaments. Whether cytoskeletal elements affect vesicle mobility in astrocytes is unknown. We labeled single vesicles with fluorescent atrial natriuretic peptide and monitored their mobility in rat astrocytes with depolymerized microtubules, actin, and intermediate filaments and in mouse astrocytes deficient in the intermediate filament proteins glial fibrillary acidic protein and vimentin. In astrocytes, as in neurons, microtubules participated in directional vesicle mobility, and actin filaments played an important role in this process. Depolymerization of intermediate filaments strongly affected vesicle trafficking and in their absence the fraction of vesicles with directional mobility was reduced.
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Affiliation(s)
- Maja Potokar
- Celica Biomedical Sciences Center, Stegne 21c, SI-1000 Ljubljana, Slovenia
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21
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Abstract
In the past few years it has been shown that, like many other non-neuroendocrine cells, adipocytes possess a mechanism for triggered exocytosis. Endocytosis and exocytosis affect the plasma membrane surface area, which can be directly monitored with electrophysiological patch-clamp techniques by measuring membrane capacitance, a parameter linearly related to the plasma membrane area. In this study we used the whole-cell mode of the patch-clamp technique to measure changes in membrane capacitance to monitor the effect of extracellular adenosine triphosphate (ATP) on the dynamics of membrane area changes in single adipocytes. Experimental evidence shows that extracellular application of ATP (100 microM) increases membrane capacitance for 30 +/- 2%. In controls a significantly smaller increase of 3 +/- 2% was measured, which is due to a slow exocytic-endocytic membrane cycling rate of 0.3%/min. We found that ATP induces a transient increase in membrane current, temporally associated with the peak rate in membrane capacitance increase. These results show directly the presence of ATP-induced increase in membrane area correlated to the increase in membrane current in single adipocytes.
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Affiliation(s)
- Helena H Chowdhury
- Laboratory for Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, School of Medicine, University of Ljubljana, Slovenia
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22
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Abstract
A key step in the intrinsic apoptotic pathway is the assembly of the apoptosome complex. The apoptosome components are well known; however, the physiology of the assembly of the apoptosome complex at the cellular level is still poorly defined. The aim of this work was to study the subcellular distribution of the apoptosome scaffold protein apoptotic protease-activating factor 1 (Apaf-1) before and after triggering apoptosis in single somatotrophs. Somatotrophs are the subject of extensive pituitary tissue remodeling in different physiological situations in which the quality and the number of pituitary cells are determined by cell proliferation and apoptosis. We show herein that 2 h after triggering apoptosis with rotenone, Apaf-1 redistributed to the proximity of mitochondria. In addition, the degree of colocalization between Apaf-1 and fluorescently labeled caspase-9 significantly increased during the same period. Furthermore, we show herein for the first time in single cells that the colocalization between Apaf-1 and cytochrome c increases only transiently, indicating a transient interaction between cytochrome c and Apaf-1 during the activation of apoptosis in these cells.
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Affiliation(s)
- Maja Potokar
- Institute of Pathophysiology, Medical Faculty, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
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Chowdhury HH, Jevsek M, Kreft M, Mars T, Zorec R, Grubic Z. Insulin-induced exocytosis in single, in vitro innervated human muscle fibres: a new approach. Pflugers Arch 2005; 450:131-5. [PMID: 15647928 DOI: 10.1007/s00424-004-1378-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Accepted: 12/14/2004] [Indexed: 12/22/2022]
Abstract
We describe a new approach for studying insulin-induced exocytosis in individual, well-differentiated, innervated human muscle fibres. We used an in vitro system in which motor axons extending from embryonic rat spinal cord explants functionally innervate co-cultured human muscle fibres. Under such conditions, the human muscle fibres reach a high degree of differentiation that is never observed in non-innervated, cultured human muscle fibres. To monitor insulin-induced membrane dynamics, we used confocal microscopy to measure the fluorescence intensity changes of the styryl dye FM1-43, a marker for membrane area. The fluorescence intensity increased after insulin stimulation. This increase, as well as the intensity of staining for the glucose transporter 4 (GLUT4), was significantly higher in the innervated and contracting fibres than in myoblasts and myotubes. This shows that in vitro innervation of human muscle cells not only enhances the differentiation stage but also improves the insulin response. Our approach allows continuous monitoring and quantitative assessment of insulin-induced increase in cumulative exocytosis in individual human muscle fibres at a differentiation level practically corresponding to that of adult muscle. It is therefore a suitable system for studying various parameters affecting the mechanisms underlying insulin-induced GLUT4 translocation in human skeletal muscle.
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Affiliation(s)
- Helena H Chowdhury
- Slovenia Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Medical School, University of Ljubljana, Zaloska 4, 1000, Ljubljana, Slovenia
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Chowdhury HH, Kreft M, Zorec R. Distinct effect of actin cytoskeleton disassembly on exo- and endocytic events in a membrane patch of rat melanotrophs. J Physiol 2002; 545:879-86. [PMID: 12482893 PMCID: PMC2290733 DOI: 10.1113/jphysiol.2002.028043] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We used the cell-attached mode of patch-clamp technique to measure discrete attofarad steps in membrane capacitance (C(m)), reporting area changes in the plasma membrane due to unitary exocytic and endocytic events. To investigate the role of the actin cytoskeleton in elementary exocytic and endocytic events, neuroendocrine rat melanotrophs were treated with Clostridium spiroforme toxin (CST), which specifically depolymerises F-actin. The average amplitude of exocytic events was not significantly different in control and in CST-treated cells. However, the amplitude of endocytic events was significantly smaller in CST-treated cells as compared to controls. The frequency of exocytic events increased by 2-fold in CST-treated cells relative to controls. In control cells the average frequency of exocytic events (upsilon;(exo)) was lower than the frequency of endocytic events (upsilon;(endo)) with a ratio upsilon;(exo)/upsilon;(endo) < 1. In the toxin treated cells, the predominant process was exocytosis with a ratio (upsilon;(exo)/upsilon;(endo) > 1). To study the coupling between the two processes, the slopes of regression lines relating upsilon;(exo) and upsilon;(endo) in a given patch of membrane were studied. The slopes of regression lines were similar, whereas the line intercepts with the y-axis were significantly different. The increased frequency of unitary exocytic events in CST-treated cells is consistent with the view, that the actin cytoskeleton acts as a barrier for exocytosis. While the disassembly of the actin cytoskeleton diminishes the size of unitary endocytic events, suggesting an important role of the actin cytoskeleton in determining the size of endocytic vesicles, the coupling between exocytosis and endocytosis in a given patch of membrane was independent of the state of the actin cytoskeleton.
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Affiliation(s)
- Helena H Chowdhury
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Medical School, University of Ljubljana, 1000 Ljubljana, Slovenia
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Chowdhury HH, Kreft M, Zorec R. Rapid insulin-induced exocytosis in white rat adipocytes. Pflugers Arch 2002; 445:352-6. [PMID: 12466937 DOI: 10.1007/s00424-002-0938-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2002] [Revised: 08/29/2002] [Accepted: 08/16/2002] [Indexed: 10/27/2022]
Abstract
Insulin is believed to increase glucose permeability of adipocytes by regulating the incorporation of glucose transporters into the plasma membrane by exocytosis. This process involves fusion of membrane-bound cellular compartments with the plasma membrane, thus influencing the plasma membrane area. However, insulin-induced changes in plasma membrane area have not yet been demonstrated. In the present study we monitored fluorescence intensity with a confocal microscope to study the effect of insulin on adipocyte plasma membrane area. After cell isolation and adhesion to a glass cover-slip, adipocytes were stained with the dye FM1-43, a membrane area reporter. At rest, the rate of fluorescence intensity increase was initially high, but gradually stabilized at 2%/min. This steady increase in fluorescence is due to a slow rate of exocytosis coupled to endocytosis, since the removal of FM1-43 from the bath did not abolish FM1-43 fluorescence. Insulin addition caused an abrupt increase of fluorescence intensity of 4%/min, which was significantly higher than in controls. These results suggest rapid, insulin-induced incorporation of new membrane into the plasma membrane by exocytosis.
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Affiliation(s)
- Helena H Chowdhury
- Loboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Medical School, University of Ljubljana, Slovenia.
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Chowdhury HH, Popoff MR, Zorec R. Actin cytoskeleton and exocytosis in rat melanotrophs. Pflugers Arch 2000; 439:R148-9. [PMID: 10653173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
We monitored secretory activity of single rat melanotrophs by the patch-clamp membrane capacitance measurements (Cm). Secretory activity was stimulated by cytosol dialysis with a patch-pipette solution containing 1 microM [Ca2+]i. Actin cytoskeleton was disaggregated by pretreating cells with Clostridium spiroforme toxin, which specifically ADP-ribosylates cellular actin. The extent of cytoskeleton disaggregation was monitored by phalloidin immunostaining. The maximal rate of secretion increases two folds in toxin-treated cells in comparison to controls, whereas the extent of calcium-induced secretory response was similar to that obtained in the non-treated cells. The results show that the subcortical actin network attenuates the rate of secretory activity, which we interpret to reflect a barrier function of cytoskeleton for exocytosis.
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Affiliation(s)
- H H Chowdhury
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Medical School, Ljubljana, Slovenia
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Chowdhury HH, Popoff MR, Zorec R. Actin cytoskeleton depolymerization with clostridium spiroforme toxin enhances the secretory activity of rat melanotrophs. J Physiol 1999; 521 Pt 2:389-95. [PMID: 10581310 PMCID: PMC2269662 DOI: 10.1111/j.1469-7793.1999.00389.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
1. We measured membrane capacitance (Cm) in cultured rat melanotrophs pretreated with Clostridium spiroforme toxin (CST), which specifically depolymerizes cortical filamentous actin (F-actin). Phalloidin staining confirmed that CST treatment depolymerised the F-actin. 2. In control cells, cytosol dialysis with 1 microM Ca2+i increased Cm by 23 +/- 4 % (n = 11) relative to the resting Cm 400 s after the start of patch rupture. In CST-treated cells the increase in Cm was 32 +/- 5 % (n = 15), not significantly different from controls. The rate of Cm increase was affected transiently by CST treatment, peaking at 1 min after patch rupture. The maximal rate of Cm increase was 4.27 +/- 0.85 fF s-1 (n = 12; measured 200 s after the start of patch rupture) in controls and 8.0 +/- 1.35 fF s-1 (n = 23; measured 75 s after the start of patch rupture) in CST-treated cells (P < 0.01). 3. In control cells cytosol dialysis with 0 microM Ca2+i decreased Cm by 9 +/- 3 % (n = 7), in CST-treated cells Cm increased by 11 +/- 3 % (n = 7) relative to resting Cm 400 s after the start of cytosol dialysis. The rate of change in Cm remained constant (controls: -1 to -2 fF s-1; CST treatment: 1-2 fF s-1). 4. Transient and sustained effects of CST treatment on changes in Cm at high or low [Ca2+]i, respectively, suggest a distinct role of cytoskeleton in Ca2+-dependent and Ca2+-independent changes in Cm. Transient enhancement of the rate of Cm by CST is consistent with a barrier role of cytoskeleton in regulated exocytosis. The sustained effect of CST on Ca2+-independent changes in Cm suggests cytoskeletal involvement in endocytosis.
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Affiliation(s)
- H H Chowdhury
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Medical School, p.p. 2211, 1001 Ljubljana, Slovenija
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