1
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Ruiz M, Devkota R, Bergh PO, Nik AM, Blid Sköldheden S, Mondejar-Duran J, Tufvesson-Alm M, Bohlooly-Y M, Sanchez D, Carlsson P, Henricsson M, Jerlhag E, Borén J, Pilon M. Aging AdipoR2-deficient mice are hyperactive with enlarged brains excessively rich in saturated fatty acids. FASEB J 2024; 38:e23815. [PMID: 38989587 DOI: 10.1096/fj.202400293rr] [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: 02/06/2024] [Revised: 06/04/2024] [Accepted: 06/28/2024] [Indexed: 07/12/2024]
Abstract
To investigate how the fatty acid composition of brain phospholipids influences brain-specific processes, we leveraged the AdipoR2 (adiponectin receptor 2) knockout mouse model in which the brain is enlarged, and cellular membranes are excessively rich in saturated fatty acids. Lipidomics analysis of brains at 2, 7, and 18 months of age showed that phosphatidylcholines, which make up about two-thirds of all cerebrum membrane lipids, contain a gross excess of saturated fatty acids in AdipoR2 knockout mice, and that this is mostly attributed to an excess palmitic acid (C16:0) at the expense of oleic acid (C18:1), consistent with a defect in fatty acid desaturation and elongation in the mutant. Specifically, there was a ~12% increase in the overall saturated fatty acid content within phosphatidylcholines and a ~30% increase in phosphatidylcholines containing two palmitic acids. Phosphatidylethanolamines, sphingomyelins, ceramides, lactosylceramides, and dihydroceramides also showed an excess of saturated fatty acids in the AdipoR2 knockout mice while nervonic acid (C24:1) was enriched at the expense of shorter saturated fatty acids in glyceroceramides. Similar defects were found in the cerebellum and myelin sheaths. Histology showed that cell density is lower in the cerebrum of AdipoR2 knockout mice, but electron microscopy did not detect reproducible defects in the ultrastructure of cerebrum neurons, though proteomics analysis showed an enrichment of electron transport chain proteins in the cerebellum. Behavioral tests showed that older (33 weeks old) AdipoR2 knockout mice are hyperactive and anxious compared to control mice of a similar age. Also, in contrast to control mice, the AdipoR2 knockout mice do not gain weight in old age but do have normal lifespans. We conclude that an excess fatty acid saturation in brain phospholipids is accompanied by hyperactivity but seems otherwise well tolerated.
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Affiliation(s)
- Mario Ruiz
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Ranjan Devkota
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Per-Olof Bergh
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Ali Moussavi Nik
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Sebastian Blid Sköldheden
- Department of Pharmacology, Institute of Neuroscience and physiology, University of Gothenburg, Gothenburg, Sweden
| | - Jorge Mondejar-Duran
- Instituto de Biomedicina y Genética Molecular, Excellence Unit, University of Valladolid-CSIC, Valladolid, Spain
| | - Maximilian Tufvesson-Alm
- Department of Pharmacology, Institute of Neuroscience and physiology, University of Gothenburg, Gothenburg, Sweden
| | | | - Diego Sanchez
- Instituto de Biomedicina y Genética Molecular, Excellence Unit, University of Valladolid-CSIC, Valladolid, Spain
| | - Peter Carlsson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Marcus Henricsson
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Elisabet Jerlhag
- Department of Pharmacology, Institute of Neuroscience and physiology, University of Gothenburg, Gothenburg, Sweden
| | - Jan Borén
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Marc Pilon
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
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2
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Avalos-Hernandez A, Juarez-Navarro K, Ruiz-Baca E, Meneses-Morales I, Espino-Saldaña E, Martinez-Torres A, Lopez-Rodriguez A. Unlocking cellular traffic jams: olive oil-mediated rescue of CNG mutant channels. Front Pharmacol 2024; 15:1408156. [PMID: 39119605 PMCID: PMC11306028 DOI: 10.3389/fphar.2024.1408156] [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: 03/27/2024] [Accepted: 06/28/2024] [Indexed: 08/10/2024] Open
Abstract
One of the reasons to suggest olive oil consumption for a healthy life is its potential to induce robust lipidomic remodeling through membrane modification by dietary lipids. This remodeling might, in turn, modulate essential lipid-protein interactions while maintaining accurate transmembrane protein/domain orientation. Oleic acid, the primary compound in olive oil, has been suggested as a modulator of ion channel function. In this study, we explored whether this lipid could rescue the trafficking of mutated transmembrane proteins. In our initial approach, we supplemented the cell culture medium of HEK-293 cells expressing cyclic nucleotide channels tagged using green fluorescent protein (CNG-GFP) with olive oil or oleic acid. In addition to wild-type channels, we also expressed R272Q and R278W mutant channels, two non-functional intracellularly retained channels related to retinopathies. We used fluorescence microscopy and patch-clamp in the inside-out configuration to assess changes in the cell localization and function of the tested channels. Our results demonstrated that olive oil and oleic acid facilitated the transport of cyclic nucleotide-gated R272Q mutant channels towards the plasma membrane, rendering them electrophysiologically functional. Thus, our findings reveal a novel property of olive oil as a membrane protein traffic inductor.
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Affiliation(s)
| | - Karina Juarez-Navarro
- Facultad de Ciencias Químicas, Universidad Juárez del Estado de Durango, Durango, Mexico
| | - Estela Ruiz-Baca
- Facultad de Ciencias Químicas, Universidad Juárez del Estado de Durango, Durango, Mexico
| | - Ivan Meneses-Morales
- Facultad de Ciencias Químicas, Universidad Juárez del Estado de Durango, Durango, Mexico
| | - Edith Espino-Saldaña
- Laboratorio de Neurobiología Molecular y Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México. Campus Juriquilla, Juriquilla, Mexico
| | - Ataulfo Martinez-Torres
- Laboratorio de Neurobiología Molecular y Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México. Campus Juriquilla, Juriquilla, Mexico
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3
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Kumar M, Has C, Lam-Kamath K, Ayciriex S, Dewett D, Bashir M, Poupault C, Schuhmann K, Thomas H, Knittelfelder O, Raghuraman BK, Ahrends R, Rister J, Shevchenko A. Lipidome Unsaturation Affects the Morphology and Proteome of the Drosophila Eye. J Proteome Res 2024; 23:1188-1199. [PMID: 38484338 PMCID: PMC11002927 DOI: 10.1021/acs.jproteome.3c00570] [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: 09/28/2023] [Revised: 02/20/2024] [Accepted: 02/25/2024] [Indexed: 03/26/2024]
Abstract
Organisms respond to dietary and environmental challenges by altering the molecular composition of their glycerolipids and glycerophospholipids (GPLs), which may favorably adjust the physicochemical properties of lipid membranes. However, how lipidome changes affect the membrane proteome and, eventually, the physiology of specific organs is an open question. We addressed this issue in Drosophila melanogaster, which is not able to synthesize sterols and polyunsaturated fatty acids but can acquire them from food. We developed a series of semisynthetic foods to manipulate the length and unsaturation of fatty acid moieties in GPLs and singled out proteins whose abundance is specifically affected by membrane lipid unsaturation in the Drosophila eye. Unexpectedly, we identified a group of proteins that have muscle-related functions and increased their abundances under unsaturated eye lipidome conditions. In contrast, the abundance of two stress response proteins, Turandot A and Smg5, is decreased by lipid unsaturation. Our findings could guide the genetic dissection of homeostatic mechanisms that maintain visual function when the eye is exposed to environmental and dietary challenges.
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Affiliation(s)
- Mukesh Kumar
- Max
Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
| | - Canan Has
- Max
Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
| | - Khanh Lam-Kamath
- Department
of Biology, University of Massachusetts
Boston, Integrated Sciences Complex, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Sophie Ayciriex
- Max
Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
| | - Deepshe Dewett
- Department
of Biology, University of Massachusetts
Boston, Integrated Sciences Complex, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Mhamed Bashir
- Department
of Biology, University of Massachusetts
Boston, Integrated Sciences Complex, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Clara Poupault
- Department
of Biology, University of Massachusetts
Boston, Integrated Sciences Complex, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Kai Schuhmann
- Max
Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
| | - Henrik Thomas
- Max
Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
| | - Oskar Knittelfelder
- Max
Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
| | - Bharath Kumar Raghuraman
- Max
Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
| | - Robert Ahrends
- Department
of Analytical Chemistry, University of Vienna, Vienna 1090, Austria
| | - Jens Rister
- Department
of Biology, University of Massachusetts
Boston, Integrated Sciences Complex, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Andrej Shevchenko
- Max
Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden 01307, Germany
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4
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Pillai EK, Franze K. Mechanics in the nervous system: From development to disease. Neuron 2024; 112:342-361. [PMID: 37967561 DOI: 10.1016/j.neuron.2023.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/29/2023] [Accepted: 10/04/2023] [Indexed: 11/17/2023]
Abstract
Physical forces are ubiquitous in biological processes across scales and diverse contexts. This review highlights the significance of mechanical forces in nervous system development, homeostasis, and disease. We provide an overview of mechanical signals present in the nervous system and delve into mechanotransduction mechanisms translating these mechanical cues into biochemical signals. During development, mechanical cues regulate a plethora of processes, including cell proliferation, differentiation, migration, network formation, and cortex folding. Forces then continue exerting their influence on physiological processes, such as neuronal activity, glial cell function, and the interplay between these different cell types. Notably, changes in tissue mechanics manifest in neurodegenerative diseases and brain tumors, potentially offering new diagnostic and therapeutic target opportunities. Understanding the role of cellular forces and tissue mechanics in nervous system physiology and pathology adds a new facet to neurobiology, shedding new light on many processes that remain incompletely understood.
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Affiliation(s)
- Eva K Pillai
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK; Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany; Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany.
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK; Institute of Medical Physics and Microtissue Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestraße 91, 91052 Erlangen, Germany; Max-Planck-Zentrum für Physik und Medizin, Kussmaulallee 1, 91054 Erlangen, Germany.
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5
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Pathak Z, Jadav T, Roy A, Chopra M, Singh N, Sengupta P, Kumar H. Maresin-1 prevents blood-spinal cord barrier disruption associated with TRPV4 elevation in the experimental model of spinal cord injury. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159395. [PMID: 37729963 DOI: 10.1016/j.bbalip.2023.159395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 09/22/2023]
Abstract
Recently, we reported the TRPV4 ion channel activation and its association with secondary damage after spinal cord injury (SCI). TRPV4 activation is linked with blood-spinal cord barrier (BSCB) disruption, endothelial damage, and inflammation after SCI. Specialized pro-resolving mediators (SPM) are endogenous lipid mediators released for inflammation resolution. Studies suggest that SPM could act as an endogenous antagonist of ion channels directly or indirectly at the plasma membrane. Herein, we studied the effect of maresin-1, a docosahexaenoic acid (DHA)-derived SPM, in SCI-induced TRPV4 expression and subsequent associated damage. First, employing a particular agonist (4αPDD) in endothelial and neuronal cell lines, we examined the potential of maresin-1 to block TRPV4 activation. Then we quantify the DHA levels in plasma and epicenter of the spinal cord in sham and at 1, 3, 7, 14, 21, and 28-days post-injury (DPI) using LC-MS. Then, we exogenously administered maresin-1 using two dosing regimens i.e., single-dose (1 μg) and multiple-dose (1 μg/day for seven days), to confirm its role in the TRPV4 inhibition and its linked damage. After SCI, DHA levels decrease in the spinal cord epicenter area as well as in the plasma. Treatment with maresin-1 attenuates TRPV4 expression, inflammatory cytokines, and chemokines and impedes neutrophil infiltration. Furthermore, treatment with maresin-1 prevents BSCB disruption, alleviates glial scar formation, and improves functional recovery. Thus, our results suggest that maresin-1 could modulate TRPV4 expression and could be a safe and promising approach to target inflammation and BSCB damage after SCI.
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Affiliation(s)
- Zarna Pathak
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Tarang Jadav
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Abhishek Roy
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Manjeet Chopra
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Nidhi Singh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Pinaki Sengupta
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat 382355, India
| | - Hemant Kumar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat 382355, India.
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6
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Kumar M, Has C, Lam-Kamath K, Ayciriex S, Dewett D, Bashir M, Poupault C, Schuhmann K, Knittelfelder O, Raghuraman BK, Ahrends R, Rister J, Shevchenko A. Lipidome unsaturation affects the morphology and proteome of the Drosophila eye. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.07.539765. [PMID: 37214967 PMCID: PMC10197557 DOI: 10.1101/2023.05.07.539765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
While the proteome of an organism is largely determined by the genome, the lipidome is shaped by a poorly understood interplay of environmental factors and metabolic processes. To gain insights into the underlying mechanisms, we analyzed the impacts of dietary lipid manipulations on the ocular proteome of Drosophila melanogaster . We manipulated the lipidome with synthetic food media that differed in the supplementation of an equal amount of saturated or polyunsaturated triacylglycerols. This allowed us to generate flies whose eyes had a highly contrasting length and unsaturation of glycerophospholipids, the major lipid class of biological membranes, while the abundance of other membrane lipid classes remained unchanged. By bioinformatically comparing the resulting ocular proteomic trends and contrasting them with the impacts of vitamin A deficiency, we identified ocular proteins whose abundances are differentially affected by lipid saturation and unsaturation. For instance, we unexpectedly identified a group of proteins that have muscle-related functions and increase their abundances in the eye upon lipidome unsaturation but are unaffected by lipidome saturation. Moreover, we identified two differentially lipid-responsive proteins involved in stress responses, Turandot A and Smg5, whose abundances decrease with lipid unsaturation. Lastly, we discovered that the ocular lipid class composition is robust to dietary changes and propose that this may be a general homeostatic feature of the organization of eukaryotic tissues, while the length and unsaturation of fatty acid moieties is more variable to compensate environmental challenges. We anticipate that these insights into the molecular responses of the Drosophila eye proteome to specific lipid manipulations will guide the genetic dissection of the mechanisms that maintain visual function when the eye is exposed to dietary challenges.
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7
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Bruserud Ø, Mosevoll KA, Bruserud Ø, Reikvam H, Wendelbo Ø. The Regulation of Neutrophil Migration in Patients with Sepsis: The Complexity of the Molecular Mechanisms and Their Modulation in Sepsis and the Heterogeneity of Sepsis Patients. Cells 2023; 12:cells12071003. [PMID: 37048076 PMCID: PMC10093057 DOI: 10.3390/cells12071003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Common causes include gram-negative and gram-positive bacteria as well as fungi. Neutrophils are among the first cells to arrive at an infection site where they function as important effector cells of the innate immune system and as regulators of the host immune response. The regulation of neutrophil migration is therefore important both for the infection-directed host response and for the development of organ dysfunctions in sepsis. Downregulation of CXCR4/CXCL12 stimulates neutrophil migration from the bone marrow. This is followed by transmigration/extravasation across the endothelial cell barrier at the infection site; this process is directed by adhesion molecules and various chemotactic gradients created by chemotactic cytokines, lipid mediators, bacterial peptides, and peptides from damaged cells. These mechanisms of neutrophil migration are modulated by sepsis, leading to reduced neutrophil migration and even reversed migration that contributes to distant organ failure. The sepsis-induced modulation seems to differ between neutrophil subsets. Furthermore, sepsis patients should be regarded as heterogeneous because neutrophil migration will possibly be further modulated by the infecting microorganisms, antimicrobial treatment, patient age/frailty/sex, other diseases (e.g., hematological malignancies and stem cell transplantation), and the metabolic status. The present review describes molecular mechanisms involved in the regulation of neutrophil migration; how these mechanisms are altered during sepsis; and how bacteria/fungi, antimicrobial treatment, and aging/frailty/comorbidity influence the regulation of neutrophil migration.
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Affiliation(s)
- Øystein Bruserud
- Leukemia Research Group, Department of Clinical Science, University of Bergen, 5021 Bergen, Norway
- Section for Hematology, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
- Correspondence:
| | - Knut Anders Mosevoll
- Section for Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
- Section for Infectious Diseases, Department of Clinical Research, University of Bergen, 5021 Bergen, Norway
| | - Øyvind Bruserud
- Department for Anesthesiology and Intensive Care, Haukeland University Hospital, 5021 Bergen, Norway
| | - Håkon Reikvam
- Leukemia Research Group, Department of Clinical Science, University of Bergen, 5021 Bergen, Norway
- Section for Hematology, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
| | - Øystein Wendelbo
- Section for Infectious Diseases, Department of Medicine, Haukeland University Hospital, 5021 Bergen, Norway
- Faculty of Health, VID Specialized University, Ulriksdal 10, 5009 Bergen, Norway
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8
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Kumar M, Has C, Lam-Kamath K, Ayciriex S, Dewett D, Bashir M, Poupault C, Schuhmann K, Knittelfelder O, Raghuraman BK, Ahrends R, Rister J, Shevchenko A. Eye proteome of Drosophila melanogaster. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.04.531088. [PMID: 36945598 PMCID: PMC10028839 DOI: 10.1101/2023.03.04.531088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
The Drosophila melanogaster eye is a popular model to elucidate the molecular mechanisms that underlie the structure and function of the eye as well as the causes of retinopathies. For instance, the Drosophila eye has been used to investigate the impacts of ageing and environmental stresses such as light-induced damage or dietary deficiencies. Moreover, large-scale screens have isolated genes whose mutation causes morphological and functional ocular defects, which includes key components of the phototransduction cascade. However, the proteome of the Drosophila eye is poorly characterized. Here, we used GeLC-MS/MS to quantify 3516 proteins he adult Drosophila melanogaster eye and provide a generic and expandable resource for further genetic, pharmacological, and dietary studies.
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9
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Romero LO, Caires R, Kaitlyn Victor A, Ramirez J, Sierra-Valdez FJ, Walsh P, Truong V, Lee J, Mayor U, Reiter LT, Vásquez V, Cordero-Morales JF. Linoleic acid improves PIEZO2 dysfunction in a mouse model of Angelman Syndrome. Nat Commun 2023; 14:1167. [PMID: 36859399 PMCID: PMC9977963 DOI: 10.1038/s41467-023-36818-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 02/17/2023] [Indexed: 03/03/2023] Open
Abstract
Angelman syndrome (AS) is a neurogenetic disorder characterized by intellectual disability and atypical behaviors. AS results from loss of expression of the E3 ubiquitin-protein ligase UBE3A from the maternal allele in neurons. Individuals with AS display impaired coordination, poor balance, and gait ataxia. PIEZO2 is a mechanosensitive ion channel essential for coordination and balance. Here, we report that PIEZO2 activity is reduced in Ube3a deficient male and female mouse sensory neurons, a human Merkel cell carcinoma cell line and female human iPSC-derived sensory neurons with UBE3A knock-down, and de-identified stem cell-derived neurons from individuals with AS. We find that loss of UBE3A decreases actin filaments and reduces PIEZO2 expression and function. A linoleic acid (LA)-enriched diet increases PIEZO2 activity, mechano-excitability, and improves gait in male AS mice. Finally, LA supplementation increases PIEZO2 function in stem cell-derived neurons from individuals with AS. We propose a mechanism whereby loss of UBE3A expression reduces PIEZO2 function and identified a fatty acid that enhances channel activity and ameliorates AS-associated mechano-sensory deficits.
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Affiliation(s)
- Luis O Romero
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, Memphis, TN, 38163, USA
| | - Rebeca Caires
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA
| | - A Kaitlyn Victor
- Department of Neurology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA
| | - Juanma Ramirez
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, UPV/EHU, Leioa, Bizkaia, Spain
| | - Francisco J Sierra-Valdez
- School of Engineering and Sciences, Tecnológico de Monterrey, Ave. Eugenio Garza Sada 2501 Sur, Monterrey, 64849, Mexico
| | | | | | - Jungsoo Lee
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA
| | - Ugo Mayor
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, UPV/EHU, Leioa, Bizkaia, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Bizkaia, Spain
| | - Lawrence T Reiter
- Department of Neurology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA
- Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38104, USA
- Department of Pediatrics, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38104, USA
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA.
| | - Julio F Cordero-Morales
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38103, USA.
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10
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Gyening YK, Chauhan NK, Tytanic M, Ea V, Brush RS, Agbaga MP. ELOVL4 Mutations That Cause Spinocerebellar Ataxia-34 Differentially Alter Very Long Chain Fatty Acid Biosynthesis. J Lipid Res 2023; 64:100317. [PMID: 36464075 PMCID: PMC9823237 DOI: 10.1016/j.jlr.2022.100317] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/28/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022] Open
Abstract
The FA Elongase-4 (ELOVL4) enzyme mediates biosynthesis of both very long chain (VLC)-PUFAs and VLC-saturated FA (VLC-SFAs). VLC-PUFAs play critical roles in retina and sperm function, whereas VLC-SFAs are predominantly associated with brain function and maintenance of the skin permeability barrier. While some ELOVL4 mutations cause Autosomal Dominant Stargardt-like Macular Dystrophy (STGD3), other ELOVL4 point mutations, such as L168F and W246G, affect the brain and/or skin, leading to Spinocerebellar Ataxia-34 (SCA34) and Erythrokeratodermia variabilis. The mechanisms by which these ELOVL4 mutations alter VLC-PUFA and VLC-SFA biosynthesis to cause the different tissue-specific pathologies are not well understood. To understand how these mutations alter VLC-PUFA and VLC-SFA biosynthesis, we expressed WT-ELOVL4, L168F, and W246G ELOVL4 variants in cell culture and supplemented the cultures with VLC-PUFA or VLC-SFA precursors. Total lipids were extracted, converted to FA methyl esters, and quantified by gas chromatography. We showed that L168F and W246G mutants were capable of VLC-PUFA biosynthesis. W246G synthesized and accumulated 32:6n3, while L168F exhibited gain of function in VLC-PUFA biosynthesis as it made 38:5n3, which we did not detect in WT-ELOVL4 or W246G-expressing cells. However, compared with WT-ELOVL4, both L168F and W246G mutants were deficient in VLC-SFA biosynthesis, especially the W246G protein, which showed negligible VLC-SFA biosynthesis. These results suggest VLC-PUFA biosynthetic capabilities of L168F and W246G in the retina, which may explain the lack of retinal phenotype in SCA34. Defects in VLC-SFA biosynthesis by these variants may be a contributing factor to the pathogenic mechanism of SCA34 and Erythrokeratodermia variabilis.
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Affiliation(s)
- Yeboah Kofi Gyening
- Departments of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Neeraj Kumar Chauhan
- Departments of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Madison Tytanic
- Departments of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Vicki Ea
- Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA
| | - Richard S Brush
- Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA; Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Martin-Paul Agbaga
- Departments of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA; Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, Oklahoma, USA; Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
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11
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Križaj D, Cordeiro S, Strauß O. Retinal TRP channels: Cell-type-specific regulators of retinal homeostasis and multimodal integration. Prog Retin Eye Res 2023; 92:101114. [PMID: 36163161 PMCID: PMC9897210 DOI: 10.1016/j.preteyeres.2022.101114] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/03/2022] [Accepted: 08/08/2022] [Indexed: 02/05/2023]
Abstract
Transient receptor potential (TRP) channels are a widely expressed family of 28 evolutionarily conserved cationic ion channels that operate as primary detectors of chemical and physical stimuli and secondary effectors of metabotropic and ionotropic receptors. In vertebrates, the channels are grouped into six related families: TRPC, TRPV, TRPM, TRPA, TRPML, and TRPP. As sensory transducers, TRP channels are ubiquitously expressed across the body and the CNS, mediating critical functions in mechanosensation, nociception, chemosensing, thermosensing, and phototransduction. This article surveys current knowledge about the expression and function of the TRP family in vertebrate retinas, which, while dedicated to transduction and transmission of visual information, are highly susceptible to non-visual stimuli. Every retinal cell expresses multiple TRP subunits, with recent evidence establishing their critical roles in paradigmatic aspects of vertebrate vision that include TRPM1-dependent transduction of ON bipolar signaling, TRPC6/7-mediated ganglion cell phototransduction, TRP/TRPL phototransduction in Drosophila and TRPV4-dependent osmoregulation, mechanotransduction, and regulation of inner and outer blood-retina barriers. TRP channels tune light-dependent and independent functions of retinal circuits by modulating the intracellular concentration of the 2nd messenger calcium, with emerging evidence implicating specific subunits in the pathogenesis of debilitating diseases such as glaucoma, ocular trauma, diabetic retinopathy, and ischemia. Elucidation of TRP channel involvement in retinal biology will yield rewards in terms of fundamental understanding of vertebrate vision and therapeutic targeting to treat diseases caused by channel dysfunction or over-activation.
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Affiliation(s)
- David Križaj
- Departments of Ophthalmology, Neurobiology, and Bioengineering, University of Utah, Salt Lake City, USA
| | - Soenke Cordeiro
- Institute of Physiology, Faculty of Medicine, Christian-Albrechts-University Kiel, Germany
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a Corporate Member of Freie Universität, Humboldt-University, The Berlin Institute of Health, Berlin, Germany.
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12
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Minke B, Pak WL. The light-activated TRP channel: the founding member of the TRP channel superfamily. J Neurogenet 2022; 36:55-64. [PMID: 36217603 DOI: 10.1080/01677063.2022.2121824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The Drosophila light-activated Transient Receptor Potential (TRP) channel is the founding member of a large and diverse family of channel proteins. The Drosophila TRP (dTRP) channel, which generates the electrical response to light has been investigated in a great detail two decades before the first mammalian TRP channel was discovered. Thus, dTRP is unique among members of the TRP channel superfamily because its physiological role and the enzymatic cascade underlying its activation are established. In this article we outline the research leading to elucidation of dTRP as the light activated channel and focus on a major physiological property of the dTRP channel, which is indirect activation via a cascade of enzymatic reactions. These detailed pioneering studies, based on the genetic dissection approach, revealed that light activation of the Drosophila TRP channel is mediated by G-Protein-Coupled Receptor (GPCR)-dependent enzymatic cascade, in which phospholipase C β (PLC) is a crucial component. This physiological mechanism of Drosophila TRP channel activation was later found in mammalian TRPC channels. However, the initial studies on the mammalian TRPV1 channel indicated that it is activated directly by capsaicin, low pH and hot temperature (>42 °C). This mechanism of activation was apparently at odds with the activation mechanism of the TRPC channels in general and the Drosophila light activated TRP/TRPL channels in particular, which are target of a GPCR-activated PLC cascade. Subsequent studies have indicated that under physiological conditions TRPV1 is also target of a GPCR-activated PLC cascade in the generation of inflammatory pain. The Drosophila light-activated TRP channel is still a useful experimental paradigm because its physiological function as the light-activated channel is known, powerful genetic techniques can be applied to its further analysis, and signaling molecules involved in the activation of these channels are available.
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Affiliation(s)
- Baruch Minke
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC), Edmond and Lily Safra Center for Brain Sciences (ELSC), Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | - William L Pak
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
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13
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Caires R, Garrud TAC, Romero LO, Fernández-Peña C, Vásquez V, Jaggar JH, Cordero-Morales JF. Genetic- and diet-induced ω-3 fatty acid enrichment enhances TRPV4-mediated vasodilation in mice. Cell Rep 2022; 40:111306. [PMID: 36070688 PMCID: PMC9498980 DOI: 10.1016/j.celrep.2022.111306] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 07/05/2022] [Accepted: 08/11/2022] [Indexed: 11/19/2022] Open
Abstract
TRPV4 channel activation in endothelial cells leads to vasodilation, while impairment of TRPV4 activity is implicated in vascular dysfunction. Strategies that increase TRPV4 activity could enhance vasodilation and ameliorate vascular disorders. Here, we show that supplementation with eicosapentaenoic acid (EPA), an ω-3 polyunsaturated fatty acid known to have beneficial cardiovascular effects, increases TRPV4 activity in human endothelial cells of various vascular beds. Mice carrying the C. elegans FAT-1 enzyme, which converts ω-6 to ω-3 polyunsaturated fatty acids, display higher EPA content and increased TRPV4-mediated vasodilation in mesenteric arteries. Likewise, mice fed an EPA-enriched diet exhibit enhanced and prolonged TRPV4-dependent vasodilation in an endothelial cell-specific manner. We also show that EPA supplementation reduces TRPV4 desensitization, which contributes to the prolonged vasodilation. Neutralization of positive charges in the TRPV4 N terminus impairs the effect of EPA on channel desensitization. These findings highlight the beneficial effects of manipulating fatty acid content to enhance TRPV4-mediated vasodilation.
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Affiliation(s)
- Rebeca Caires
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Tessa A C Garrud
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Luis O Romero
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, Memphis, TN 38163, USA
| | - Carlos Fernández-Peña
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jonathan H Jaggar
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Julio F Cordero-Morales
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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14
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Vitamin A Deficiency Alters the Phototransduction Machinery and Distinct Non-Vision-Specific Pathways in the Drosophila Eye Proteome. Biomolecules 2022; 12:biom12081083. [PMID: 36008977 PMCID: PMC9405971 DOI: 10.3390/biom12081083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/25/2022] Open
Abstract
The requirement of vitamin A for the synthesis of the visual chromophore and the light-sensing pigments has been studied in vertebrate and invertebrate model organisms. To identify the molecular mechanisms that orchestrate the ocular response to vitamin A deprivation, we took advantage of the fact that Drosophila melanogaster predominantly requires vitamin A for vision, but not for development or survival. We analyzed the impacts of vitamin A deficiency on the morphology, the lipidome, and the proteome of the Drosophila eye. We found that chronic vitamin A deprivation damaged the light-sensing compartments and caused a dramatic loss of visual pigments, but also decreased the molar abundance of most phototransduction proteins that amplify and transduce the visual signal. Unexpectedly, vitamin A deficiency also decreased the abundances of specific subunits of mitochondrial TCA cycle and respiratory chain components but increased the levels of cuticle- and lens-related proteins. In contrast, we found no apparent effects of vitamin A deficiency on the ocular lipidome. In summary, chronic vitamin A deficiency decreases the levels of most components of the visual signaling pathway, but also affects molecular pathways that are not vision-specific and whose mechanistic connection to vitamin A remains to be elucidated.
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15
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Jensen JB, Falkenburger BH, Dickson EJ, de la Cruz L, Dai G, Myeong J, Jung SR, Kruse M, Vivas O, Suh BC, Hille B. Biophysical physiology of phosphoinositide rapid dynamics and regulation in living cells. J Gen Physiol 2022; 154:e202113074. [PMID: 35583815 PMCID: PMC9121023 DOI: 10.1085/jgp.202113074] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 04/28/2022] [Indexed: 01/07/2023] Open
Abstract
Phosphoinositide membrane lipids are ubiquitous low-abundance signaling molecules. They direct many physiological processes that involve ion channels, membrane identification, fusion of membrane vesicles, and vesicular endocytosis. Pools of these lipids are continually broken down and refilled in living cells, and the rates of some of these reactions are strongly accelerated by physiological stimuli. Recent biophysical experiments described here measure and model the kinetics and regulation of these lipid signals in intact cells. Rapid on-line monitoring of phosphoinositide metabolism is made possible by optical tools and electrophysiology. The experiments reviewed here reveal that as for other cellular second messengers, the dynamic turnover and lifetimes of membrane phosphoinositides are measured in seconds, controlling and timing rapid physiological responses, and the signaling is under strong metabolic regulation. The underlying mechanisms of this metabolic regulation remain questions for the future.
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Affiliation(s)
- Jill B. Jensen
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | | | - Eamonn J. Dickson
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA
| | - Lizbeth de la Cruz
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Gucan Dai
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO
| | - Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University in St. Louis, St. Louis, MO
| | | | - Martin Kruse
- Department of Biology and Program in Neuroscience, Bates College, Lewiston, ME
| | - Oscar Vivas
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Byung-Chang Suh
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
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16
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Kanehara K, Cho Y, Yu CY. A lipid viewpoint on the plant endoplasmic reticulum stress response. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2835-2847. [PMID: 35560195 DOI: 10.1093/jxb/erac063] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/15/2022] [Indexed: 06/15/2023]
Abstract
Organisms, including humans, seem to be constantly exposed to various changes, which often have undesirable effects, referred to as stress. To keep up with these changes, eukaryotic cells may have evolved a number of relevant cellular processes, such as the endoplasmic reticulum (ER) stress response. Owing to presumably intimate links between human diseases and the ER function, the ER stress response has been extensively investigated in various organisms for a few decades. Based on these studies, we now have a picture of the molecular mechanisms of the ER stress response, one of which, the unfolded protein response (UPR), is highly conserved among yeasts, mammals, higher plants, and green algae. In this review, we attempt to highlight the plant UPR from the perspective of lipids, especially membrane phospholipids. Phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) are the most abundant membrane phospholipids in eukaryotic cells. The ratio of PtdCho to PtdEtn and the unsaturation of fatty acyl tails in both phospholipids may be critical factors for the UPR, but the pathways responsible for PtdCho and PtdEtn biosynthesis are distinct in animals and plants. We discuss the plant UPR in comparison with the system in yeasts and animals in the context of membrane phospholipids.
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Affiliation(s)
- Kazue Kanehara
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Yueh Cho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Chao-Yuan Yu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
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17
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The Role of Membrane Lipids in Light-Activation of Drosophila TRP Channels. Biomolecules 2022; 12:biom12030382. [PMID: 35327573 PMCID: PMC8945425 DOI: 10.3390/biom12030382] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 12/28/2022] Open
Abstract
Transient Receptor Potential (TRP) channels constitute a large superfamily of polymodal channel proteins with diverse roles in many physiological and sensory systems that function both as ionotropic and metabotropic receptors. From the early days of TRP channel discovery, membrane lipids were suggested to play a fundamental role in channel activation and regulation. A prominent example is the Drosophila TRP and TRP-like (TRPL) channels, which are predominantly expressed in the visual system of Drosophila. Light activation of the TRP and TRPL channels, the founding members of the TRP channel superfamily, requires activation of phospholipase Cβ (PLC), which hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into Diacylglycerol (DAG) and Inositol 1, 4,5-trisphosphate (IP3). However, the events required for channel gating downstream of PLC activation are still under debate and led to several hypotheses regarding the mechanisms by which lipids gate the channels. Despite many efforts, compelling evidence of the involvement of DAG accumulation, PIP2 depletion or IP3-mediated Ca2+ release in light activation of the TRP/TRPL channels are still lacking. Exogeneous application of poly unsaturated fatty acids (PUFAs), a product of DAG hydrolysis was demonstrated as an efficient way to activate the Drosophila TRP/TRPL channels. However, compelling evidence for the involvement of PUFAs in physiological light-activation of the TRP/TRPL channels is still lacking. Light-induced mechanical force generation was measured in photoreceptor cells prior to channel opening. This mechanical force depends on PLC activity, suggesting that the enzymatic activity of PLC converting PIP2 into DAG generates membrane tension, leading to mechanical gating of the channels. In this review, we will present the roles of membrane lipids in light activation of Drosophila TRP channels and present the many advantages of this model system in the exploration of TRP channel activation under physiological conditions.
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18
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Tsai MC, Fleuriot L, Janel S, Gonzalez-Rodriguez D, Morel C, Mettouchi A, Debayle D, Dallongeville S, Olivo-Marin JC, Antonny B, Lafont F, Lemichez E, Barelli H. DHA-phospholipids control membrane fusion and transcellular tunnel dynamics. J Cell Sci 2021; 135:273659. [PMID: 34878112 DOI: 10.1242/jcs.259119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/27/2021] [Indexed: 11/20/2022] Open
Abstract
Metabolic studies and animal knockout models point to the critical role of polyunsaturated docosahexaenoic acid (22:6, DHA)-containing phospholipids (PLs) in physiology. Here, we investigated the impact of DHA-PLs on the dynamics of transendothelial cell macroapertures (TEMs) triggered by RhoA inhibition-associated cell spreading. Lipidomic analyses show that human umbilical vein endothelial cells (HUVECs) subjected to DHA-diet undergo a 6-fold enrichment in DHA-PLs at plasma membrane (PM) at the expense of monounsaturated OA-PLs. Consequently, DHA-PLs enrichment at the PM induces a reduction of cell thickness and shifts cellular membranes towards a permissive mode of membrane fusion for transcellular tunnel initiation. We provide evidence that a global homeostatic control of membrane tension and cell cortex rigidity minimizes overall changes of TEM area through a decrease of TEM size and lifetime. Conversely, low DHA-PL levels at the PM leads to the opening of unstable and wider TEMs. Together, this provides evidence that variations of DHA-PLs levels in membranes affect cell biomechanical properties.
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Affiliation(s)
- Meng-Chen Tsai
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275, CNRS and Université Côte d'Azur, 06560, Valbonne, France.,Institut Pasteur, Université de Paris, CNRS UMR2001, Unité des Toxines Bactériennes, 75015 Paris, France
| | - Lucile Fleuriot
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275, CNRS and Université Côte d'Azur, 06560, Valbonne, France
| | - Sébastien Janel
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | | | - Camille Morel
- Institut Pasteur, Université de Paris, CNRS UMR2001, Unité des Toxines Bactériennes, 75015 Paris, France
| | - Amel Mettouchi
- Institut Pasteur, Université de Paris, CNRS UMR2001, Unité des Toxines Bactériennes, 75015 Paris, France
| | - Delphine Debayle
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275, CNRS and Université Côte d'Azur, 06560, Valbonne, France
| | | | | | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275, CNRS and Université Côte d'Azur, 06560, Valbonne, France
| | - Frank Lafont
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Emmanuel Lemichez
- Institut Pasteur, Université de Paris, CNRS UMR2001, Unité des Toxines Bactériennes, 75015 Paris, France
| | - Hélène Barelli
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275, CNRS and Université Côte d'Azur, 06560, Valbonne, France
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19
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Dewett D, Labaf M, Lam-Kamath K, Zarringhalam K, Rister J. Vitamin A deficiency affects gene expression in the Drosophila melanogaster head. G3 (BETHESDA, MD.) 2021; 11:jkab297. [PMID: 34849795 PMCID: PMC8527478 DOI: 10.1093/g3journal/jkab297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/13/2021] [Indexed: 12/13/2022]
Abstract
Insufficient dietary intake of vitamin A causes various human diseases. For instance, chronic vitamin A deprivation causes blindness, slow growth, impaired immunity, and an increased risk of mortality in children. In contrast to these diverse effects of vitamin A deficiency (VAD) in mammals, chronic VAD in flies neither causes obvious developmental defects nor lethality. As in mammals, VAD in flies severely affects the visual system: it impairs the synthesis of the retinal chromophore, disrupts the formation of the visual pigments (Rhodopsins), and damages the photoreceptors. However, the molecular mechanisms that respond to VAD remain poorly understood. To identify genes and signaling pathways that are affected by VAD, we performed RNA-sequencing and differential gene expression analysis in Drosophila melanogaster. We found an upregulation of genes that are essential for the synthesis of the retinal chromophore, specific aminoacyl-tRNA synthetases, and major nutrient reservoir proteins. We also discovered that VAD affects several genes that are required for the termination of the light response: for instance, we found a downregulation of both arrestin genes that are essential for the inactivation of Rhodopsin. A comparison of the VAD-responsive genes with previously identified blue light stress-responsive genes revealed that the two types of environmental stress trigger largely nonoverlapping transcriptome responses. Yet, both stresses increase the expression of seven genes with poorly understood functions. Taken together, our transcriptome analysis offers insights into the molecular mechanisms that respond to environmental stresses.
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Affiliation(s)
- Deepshe Dewett
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Maryam Labaf
- Department of Mathematics, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Khanh Lam-Kamath
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Kourosh Zarringhalam
- Department of Mathematics, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Jens Rister
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
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20
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Kruse M, Whitten RJ. Control of Neuronal Excitability by Cell Surface Receptor Density and Phosphoinositide Metabolism. Front Pharmacol 2021; 12:663840. [PMID: 33967808 PMCID: PMC8097148 DOI: 10.3389/fphar.2021.663840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/29/2021] [Indexed: 12/27/2022] Open
Abstract
Phosphoinositides are members of a family of minor phospholipids that make up about 1% of all lipids in most cell types. Despite their low abundance they have been found to be essential regulators of neuronal activities such as action potential firing, release and re-uptake of neurotransmitters, and interaction of cytoskeletal proteins with the plasma membrane. Activation of several different neurotransmitter receptors can deplete phosphoinositide levels by more than 90% in seconds, thereby profoundly altering neuronal behavior; however, despite the physiological importance of this mechanism we still lack a profound quantitative understanding of the connection between phosphoinositide metabolism and neuronal activity. Here, we present a model that describes phosphoinositide metabolism and phosphoinositide-dependent action potential firing in sympathetic neurons. The model allows for a simulation of activation of muscarinic acetylcholine receptors and its effects on phosphoinositide levels and their regulation of action potential firing in these neurons. In this paper, we describe the characteristics of the model, its calibration to experimental data, and use the model to analyze how alterations of surface density of muscarinic acetylcholine receptors or altered activity levels of a key enzyme of phosphoinositide metabolism influence action potential firing of sympathetic neurons. In conclusion, the model provides a comprehensive framework describing the connection between muscarinic acetylcholine signaling, phosphoinositide metabolism, and action potential firing in sympathetic neurons which can be used to study the role of these signaling systems in health and disease.
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Affiliation(s)
- Martin Kruse
- Department of Biology, Bates College, Lewiston, ME, United States
- Program in Neuroscience, Bates College, Lewiston, ME, United States
| | - Rayne J. Whitten
- Program in Neuroscience, Bates College, Lewiston, ME, United States
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21
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Hebbar S, Schuhmann K, Shevchenko A, Knust E. Hydroxylated sphingolipid biosynthesis regulates photoreceptor apical domain morphogenesis. J Cell Biol 2020; 219:211460. [PMID: 33048164 PMCID: PMC7557679 DOI: 10.1083/jcb.201911100] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 08/07/2020] [Accepted: 09/08/2020] [Indexed: 01/04/2023] Open
Abstract
Apical domains of epithelial cells often undergo dramatic changes during morphogenesis to form specialized structures, such as microvilli. Here, we addressed the role of lipids during morphogenesis of the rhabdomere, the microvilli-based photosensitive organelle of Drosophila photoreceptor cells. Shotgun lipidomics analysis performed on mutant alleles of the polarity regulator crumbs, exhibiting varying rhabdomeric growth defects, revealed a correlation between increased abundance of hydroxylated sphingolipids and abnormal rhabdomeric growth. This could be attributed to an up-regulation of fatty acid hydroxylase transcription. Indeed, direct genetic perturbation of the hydroxylated sphingolipid metabolism modulated rhabdomere growth in a crumbs mutant background. One of the pathways targeted by sphingolipid metabolism turned out to be the secretory route of newly synthesized Rhodopsin, a major rhabdomeric protein. In particular, altered biosynthesis of hydroxylated sphingolipids impaired apical trafficking via Rab11, and thus apical membrane growth. The intersection of lipid metabolic pathways with apical domain growth provides a new facet to our understanding of apical growth during morphogenesis.
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22
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Zhao H, Wang T. PE homeostasis rebalanced through mitochondria-ER lipid exchange prevents retinal degeneration in Drosophila. PLoS Genet 2020; 16:e1009070. [PMID: 33064773 PMCID: PMC7592913 DOI: 10.1371/journal.pgen.1009070] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/28/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023] Open
Abstract
The major glycerophospholipid phosphatidylethanolamine (PE) in the nervous system is essential for neural development and function. There are two major PE synthesis pathways, the CDP-ethanolamine pathway in the endoplasmic reticulum (ER) and the phosphatidylserine decarboxylase (PSD) pathway in mitochondria. However, the role played by mitochondrial PE synthesis in maintaining cellular PE homeostasis is unknown. Here, we show that Drosophila pect (phosphoethanolamine cytidylyltransferase) mutants lacking the CDP-ethanolamine pathway, exhibited alterations in phospholipid composition, defective phototransduction, and retinal degeneration. Induction of the PSD pathway fully restored levels and composition of cellular PE, thus rescued the retinal degeneration and defective visual responses in pect mutants. Disrupting lipid exchange between mitochondria and ER blocked the ability of PSD to rescue pect mutant phenotypes. These findings provide direct evidence that the synthesis of PE in mitochondria contributes to cellular PE homeostasis, and suggest the induction of mitochondrial PE synthesis as a promising therapeutic approach for disorders associated with PE deficiency.
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Affiliation(s)
- Haifang Zhao
- National Institute of Biological Sciences, Beijing, China
| | - Tao Wang
- National Institute of Biological Sciences, Beijing, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
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23
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Bozelli JC, Epand RM. Specificity of Acyl Chain Composition of Phosphatidylinositols. Proteomics 2020; 19:e1900138. [PMID: 31381272 DOI: 10.1002/pmic.201900138] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/30/2019] [Indexed: 01/15/2023]
Abstract
Phosphatidylinositol (PI) lipids have a predominance of a single molecular species present through the organism. In healthy mammals this molecular species is 1-stearoyl-2-arachidonoyl (18:0/20:4) PI. Although the importance of PI lipids for cell physiology has long been appreciated, less is known about the biological role of enriching PI lipids with 18:0/20:4 acyl chains. In conditions with dysfunctional lipid metabolism, the predominance of 18:0/20:4 acyl chains is lost. Recently, molecular mechanisms underpinning the enrichment or alteration of these acyl chains in PI lipids have begun to emerge. In the majority of the cases a common feature is the presence of enzymes bearing substrate acyl chain specificity. However, in cancer cells, it has been shown that one (not the only) of the mechanisms responsible for the loss in this acyl chain enrichment is mutation on the transcription factor p53 gene, which is one of the most highly mutated genes in cancers. There is a compelling need for a global picture of the specificity of the acyl chain composition of PIs. This can be possible once high-resolution spatio-temporal information is gathered in a cellular context; which can ultimately lead to potential novel targets to combat conditions with altered PI acyl chain profiles.
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Affiliation(s)
- José Carlos Bozelli
- Department of Biochemistry and Biomedical Sciences, McMaster University Health Sciences Centre, Hamilton, Ontario, L8S 4K1, Canada
| | - Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University Health Sciences Centre, Hamilton, Ontario, L8S 4K1, Canada
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Ogueta M, Hardie RC, Stanewsky R. Light Sampling via Throttled Visual Phototransduction Robustly Synchronizes the Drosophila Circadian Clock. Curr Biol 2020; 30:2551-2563.e3. [PMID: 32502413 DOI: 10.1016/j.cub.2020.04.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/07/2020] [Accepted: 04/24/2020] [Indexed: 01/19/2023]
Abstract
The daily changes of light and dark exemplify a prominent cue for the synchronization of circadian clocks with the environment. The match between external and internal time is crucial for the fitness of organisms, and desynchronization has been linked to numerous physical and mental health problems. Organisms therefore developed complex and not fully understood mechanisms to synchronize their circadian clock to light. In mammals and in Drosophila, both the visual system and non-image-forming photoreceptors contribute to circadian clock resetting. In Drosophila, light-dependent degradation of the clock protein TIMELESS by the blue light photoreceptor Cryptochrome is considered the main mechanism for clock synchronization, although the visual system also contributes. To better understand the visual system contribution, we generated a genetic variant exhibiting extremely slow phototransduction kinetics, yet normal sensitivity. In this variant, the visual system is able to contribute its full share to circadian clock entrainment, both with regard to behavioral and molecular light synchronization. This function depends on an alternative phospholipase C-β enzyme, encoded by PLC21C, presumably playing a dedicated role in clock resetting. We show that this pathway requires the ubiquitin ligase CULLIN-3, possibly mediating CRY-independent degradation of TIMELESS during light:dark cycles. Our results suggest that the PLC21C-mediated contribution to circadian clock entrainment operates on a drastically slower timescale compared with fast, norpA-dependent visual phototransduction. Our findings are therefore consistent with the general idea that the visual system samples light over prolonged periods of time (h) in order to reliably synchronize their internal clocks with the external time.
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Affiliation(s)
- Maite Ogueta
- Institute of Neuro and Behavioral Biology, Westfälische Wilhelms University, 48149 Münster, Germany
| | - Roger C Hardie
- Department of Physiology, Development, and Neuroscience, Cambridge University, Cambridge CB2 3EG, UK
| | - Ralf Stanewsky
- Institute of Neuro and Behavioral Biology, Westfälische Wilhelms University, 48149 Münster, Germany.
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25
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Thakur DP, Wang Q, Jeon J, Tian JB, Zhu MX. Intracellular acidification facilitates receptor-operated TRPC4 activation through PLCδ1 in a Ca 2+ -dependent manner. J Physiol 2020; 598:2651-2667. [PMID: 32338378 DOI: 10.1113/jp279658] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/20/2020] [Indexed: 12/28/2022] Open
Abstract
KEY POINTS Receptor-operated activation of TRPC4 cation channels requires Gi/o proteins and phospholipase-Cδ1 (PLCδ1) activation by intracellular Ca2+ . Concurrent stimulation of the Gq/11 pathway accelerates Gi/o activation of TRPC4, which is not mimicked by increasing cytosolic Ca2+ . The kinetic effect of Gq/11 was diminished by alkaline intracellular pH (pHi ) and increased pHi buffer capacity. Acidic pHi (6.75-6.25) together with the cytosolic Ca2+ rise accelerated Gi/o -mediated TRPC4 activation. Protons exert their facilitation effect through Ca2+ -dependent activation of PLCδ1. The data suggest that the Gq/11 -PLCβ pathway facilitates Gi/o activation of TRPC4 through hydrolysing phosphatidylinositol 4,5-bisphosphate (PIP2 ) to produce the initial proton signal that triggers a self-propagating PLCδ1 activity supported by regenerative H+ and Ca2+ . The findings provide novel mechanistic insights into receptor-operated TRPC4 activation by coincident Gq/11 and Gi/o pathways and shed light on how aberrant activation of TRPC4 may occur under pathological conditions to cause cell damage. ABSTRACT Transient Receptor Potential Canonical 4 (TRPC4) forms non-selective cation channels activated downstream from receptors that signal through G proteins. Our recent work suggests that TRPC4 channels are particularly coupled to pertussis toxin-sensitive Gi/o proteins, with a co-dependence on phospholipase-Cδ1 (PLCδ1). The Gi/o -mediated TRPC4 activation is dually dependent on and bimodally regulated by phosphatidylinositol 4,5-bisphosphate (PIP2 ), the substrate hydrolysed by PLC, and intracellular Ca2+ . As a byproduct of PLC-mediated PIP2 hydrolysis, protons have been shown to play an important role in the activation of Drosophila TRP channels. However, how intracellular pH affects mammalian TRPC channels remains obscure. Here, using patch-clamp recordings of HEK293 cells heterologously co-expressing mouse TRPC4β and the Gi/o -coupled μ opioid receptor, we investigated the role of intracellular protons on Gi/o -mediated TRPC4 activation. We found that acidic cytosolic pH greatly accelerated the rate of TRPC4 activation without altering the maximal current density and this effect was dependent on intracellular Ca2+ elevation. However, protons did not accelerate channel activation by directly acting upon TRPC4. We additionally demonstrated that protons exert their effect through sensitization of PLCδ1 to Ca2+ , which in turn promotes PLCδ1 activity and further potentiates TRPC4 via a positive feedback mechanism. The mechanism elucidated here helps explain how Gi/o and Gq/11 co-stimulation induces a faster activation of TRPC4 than Gi/o activation alone and highlights again the critical role of PLCδ1 in TRPC4 gating.
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Affiliation(s)
- Dhananjay P Thakur
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Qiaochu Wang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Jaepyo Jeon
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Jin-Bin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
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Di Miceli M, Bosch-Bouju C, Layé S. PUFA and their derivatives in neurotransmission and synapses: a new hallmark of synaptopathies. Proc Nutr Soc 2020; 79:1-16. [PMID: 32299516 DOI: 10.1017/s0029665120000129] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PUFA of the n-3 and n-6 families are present in high concentration in the brain where they are major components of cell membranes. The main forms found in the brain are DHA (22 :6, n-3) and arachidonic acid (20:4, n-6). In the past century, several studies pinpointed that modifications of n-3 and n-6 PUFA levels in the brain through dietary supply or genetic means are linked to the alterations of synaptic function. Yet, synaptopathies emerge as a common characteristic of neurodevelopmental disorders, neuropsychiatric diseases and some neurodegenerative diseases. Understanding the mechanisms of action underlying the activity of PUFA at the level of synapses is thus of high interest. In this frame, dietary supplementation in PUFA aiming at restoring or promoting the optimal function of synapses appears as a promising strategy to treat synaptopathies. This paper reviews the link between dietary PUFA, synapse formation and the role of PUFA and their metabolites in synaptic functions.
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Affiliation(s)
- Mathieu Di Miceli
- INRAE, University of Bordeaux, Bordeaux INP, NutriNeuro, UMR 1286, F-33000, Bordeaux, France
| | - Clémentine Bosch-Bouju
- INRAE, University of Bordeaux, Bordeaux INP, NutriNeuro, UMR 1286, F-33000, Bordeaux, France
| | - Sophie Layé
- INRAE, University of Bordeaux, Bordeaux INP, NutriNeuro, UMR 1286, F-33000, Bordeaux, France
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Rapid Release of Ca 2+ from Endoplasmic Reticulum Mediated by Na +/Ca 2+ Exchange. J Neurosci 2020; 40:3152-3164. [PMID: 32156830 DOI: 10.1523/jneurosci.2675-19.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/04/2020] [Accepted: 02/12/2020] [Indexed: 11/21/2022] Open
Abstract
Phototransduction in Drosophila is mediated by phospholipase C (PLC) and Ca2+-permeable TRP channels, but the function of endoplasmic reticulum (ER) Ca2+ stores in this important model for Ca2+ signaling remains obscure. We therefore expressed a low affinity Ca2+ indicator (ER-GCaMP6-150) in the ER, and measured its fluorescence both in dissociated ommatidia and in vivo from intact flies of both sexes. Blue excitation light induced a rapid (tau ∼0.8 s), PLC-dependent decrease in fluorescence, representing depletion of ER Ca2+ stores, followed by a slower decay, typically reaching ∼50% of initial dark-adapted levels, with significant depletion occurring under natural levels of illumination. The ER stores refilled in the dark within 100-200 s. Both rapid and slow store depletion were largely unaffected in InsP3 receptor mutants, but were much reduced in trp mutants. Strikingly, rapid (but not slow) depletion of ER stores was blocked by removing external Na+ and in mutants of the Na+/Ca2+ exchanger, CalX, which we immuno-localized to ER membranes in addition to its established localization in the plasma membrane. Conversely, overexpression of calx greatly enhanced rapid depletion. These results indicate that rapid store depletion is mediated by Na+/Ca2+ exchange across the ER membrane induced by Na+ influx via the light-sensitive channels. Although too slow to be involved in channel activation, this Na+/Ca2+ exchange-dependent release explains the decades-old observation of a light-induced rise in cytosolic Ca2+ in photoreceptors exposed to Ca2+-free solutions.SIGNIFICANCE STATEMENT Phototransduction in Drosophila is mediated by phospholipase C, which activates TRP cation channels by an unknown mechanism. Despite much speculation, it is unknown whether endoplasmic reticulum (ER) Ca2+ stores play any role. We therefore engineered flies expressing a genetically encoded Ca2+ indicator in the photoreceptor ER. Although NCX Na+/Ca2+ exchangers are classically believed to operate only at the plasma membrane, we demonstrate a rapid light-induced depletion of ER Ca2+ stores mediated by Na+/Ca2+ exchange across the ER membrane. This NCX-dependent release was too slow to be involved in channel activation, but explains the decades-old observation of a light-induced rise in cytosolic Ca2+ in photoreceptors bathed in Ca2+-free solutions.
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Parkinson's disease-associated iPLA2-VIA/PLA2G6 regulates neuronal functions and α-synuclein stability through membrane remodeling. Proc Natl Acad Sci U S A 2019; 116:20689-20699. [PMID: 31548400 PMCID: PMC6789907 DOI: 10.1073/pnas.1902958116] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The mechanisms of α-synuclein aggregation and subsequent Lewy body formation are a key pathogenesis of Parkinson’s disease (PD). PARK14-linked PD, which is caused by mutations of the iPLA2-VIA/PLA2G6 gene, exhibits a marked Lewy body pathology. iPLA2-VIA, which belongs to the phospholipase A2 family, is another causative gene of neurodegeneration with brain iron accumulation (NBIA). Here, we demonstrate that iPLA2-VIA loss results in acyl-chain shortening in phospholipids, which affects ER homeostasis and neurotransmission and promotes α-synuclein aggregation. The administration of linoleic acid or the overexpression of C19orf12, one of the NBIA-causative genes, also suppresses the acyl-chain shortening by iPLA2-VIA loss. The rescue of iPLA2-VIA phenotypes by C19orf12 provides significant molecular insight into the underlying common pathogenesis of PD and NBIA. Mutations in the iPLA2-VIA/PLA2G6 gene are responsible for PARK14-linked Parkinson’s disease (PD) with α-synucleinopathy. However, it is unclear how iPLA2-VIA mutations lead to α-synuclein (α-Syn) aggregation and dopaminergic (DA) neurodegeneration. Here, we report that iPLA2-VIA–deficient Drosophila exhibits defects in neurotransmission during early developmental stages and progressive cell loss throughout the brain, including degeneration of the DA neurons. Lipid analysis of brain tissues reveals that the acyl-chain length of phospholipids is shortened by iPLA2-VIA loss, which causes endoplasmic reticulum (ER) stress through membrane lipid disequilibrium. The introduction of wild-type human iPLA2-VIA or the mitochondria–ER contact site-resident protein C19orf12 in iPLA2-VIA–deficient flies rescues the phenotypes associated with altered lipid composition, ER stress, and DA neurodegeneration, whereas the introduction of a disease-associated missense mutant, iPLA2-VIA A80T, fails to suppress these phenotypes. The acceleration of α-Syn aggregation by iPLA2-VIA loss is suppressed by the administration of linoleic acid, correcting the brain lipid composition. Our findings suggest that membrane remodeling by iPLA2-VIA is required for the survival of DA neurons and α-Syn stability.
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Romero LO, Massey AE, Mata-Daboin AD, Sierra-Valdez FJ, Chauhan SC, Cordero-Morales JF, Vásquez V. Dietary fatty acids fine-tune Piezo1 mechanical response. Nat Commun 2019; 10:1200. [PMID: 30867417 PMCID: PMC6416271 DOI: 10.1038/s41467-019-09055-7] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/18/2019] [Indexed: 12/18/2022] Open
Abstract
Mechanosensitive ion channels rely on membrane composition to transduce physical stimuli into electrical signals. The Piezo1 channel mediates mechanoelectrical transduction and regulates crucial physiological processes, including vascular architecture and remodeling, cell migration, and erythrocyte volume. The identity of the membrane components that modulate Piezo1 function remain largely unknown. Using lipid profiling analyses, we here identify dietary fatty acids that tune Piezo1 mechanical response. We find that margaric acid, a saturated fatty acid present in dairy products and fish, inhibits Piezo1 activation and polyunsaturated fatty acids (PUFAs), present in fish oils, modulate channel inactivation. Force measurements reveal that margaric acid increases membrane bending stiffness, whereas PUFAs decrease it. We use fatty acid supplementation to abrogate the phenotype of gain-of-function Piezo1 mutations causing human dehydrated hereditary stomatocytosis. Beyond Piezo1, our findings demonstrate that cell-intrinsic lipid profile and changes in the fatty acid metabolism can dictate the cell's response to mechanical cues.
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Affiliation(s)
- Luis O Romero
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Andrew E Massey
- Department of Pharmaceutical Sciences and Institute of Biomarker and Molecular Therapeutics (IBMT), College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Ave., Memphis, TN, 38163, USA
| | - Alejandro D Mata-Daboin
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Francisco J Sierra-Valdez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
- Centro de Investigación Biomédica, Hospital Zambrano Hellion, TecSalud, Ave. Batallon de San Patricio 112, 66278, San Pedro Garza García, Nuevo León, Mexico
- Tecnólogico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501 Sur, 64849, Monterrey, Nuevo León, Mexico
| | - Subhash C Chauhan
- Department of Pharmaceutical Sciences and Institute of Biomarker and Molecular Therapeutics (IBMT), College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Ave., Memphis, TN, 38163, USA
| | - Julio F Cordero-Morales
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA.
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30
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Solovev IA, Shaposhnikov MV, Moskalev AA. Genetic mechanisms of the influence of light and phototransduction on Drosophila melanogaster lifespan. Vavilovskii Zhurnal Genet Selektsii 2018. [DOI: 10.18699/vj18.429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The light of the visible spectrum (with wavelengths of 380-780 nm) is one of the fundamental abiotic factors to which organisms have been adapting since the start of biological evolution on the Earth. Numerous literature sources establish a connection between the duration of exposure to daylight, carcinogenesis and longevity, convincingly showing a significant reduction in the incidence of cancer in blind people, as well as in animal models. On the other hand, the stimulating nature of the effect of continuous illumination on reproductive function was noted, in particular, the effects of increasing the fecundity of females of various species are known. Increase in motor activity and, as a result, in metabolic rate and thermogenesis during permanent exposure to light also reduces the body's energy reserves and lifespan. In principle, in the context of aging, not only the exposure time, but also the age at the onset of exposure to constant illumination matter, the reverse effects are valid for the maintenance of experimental animals in the constant darkness. Over the long period of the evolution of light signal transduction systems, many mechanisms have emerged that allow to form an adequate response of the organism to illumination, modulating the highly conservative signaling cascades, including those associated with aging and lifespan (FOXO, SIRT1, NF-kB, mTOR/S6k, PPARa, etc). In this review, we consider the relationship between lifespan, photoregimens, and also the expression of the genes encoding the phototransduction cascade and the circadian oscillator elements of animal cells. In the present paper, basic transducers of light and other signals, such as the family of TRP receptors, G proteins, phospholipase C, and others, are considered in the context of aging and longevity. A relationship between the mechanisms of thermoreception, the temperature synchronization of the circadian oscillator and the life span is established in the review. Analysis of experimental data obtained from the Drosophila melano-gaster model allowed us to formulate the hypothesis of age-dependent photoresistance - a gradual decrease in the expression of genes associated with phototransduction and circadian oscillators, leading to deterioration in the ability to adapt to the photoregimen and to the increase in the rate of aging.
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Affiliation(s)
- I. A. Solovev
- Institute of Biology of Komi Scientific Center, UrB RAS; Pitirim Sorokin Syktyvkar State University, Department of Ecology, Institute of Natural Sciences
| | | | - A. A. Moskalev
- Institute of Biology of Komi Scientific Center, UrB RAS; Pitirim Sorokin Syktyvkar State University, Department of Ecology, Institute of Natural Sciences; Moscow Institute of Physics and Technology; Engelhardt Institute of Molecular Biology, RAS; Vavilov Institute of General Genetics, RAS
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31
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Brankatschk M, Gutmann T, Knittelfelder O, Palladini A, Prince E, Grzybek M, Brankatschk B, Shevchenko A, Coskun Ü, Eaton S. A Temperature-Dependent Switch in Feeding Preference Improves Drosophila Development and Survival in the Cold. Dev Cell 2018; 46:781-793.e4. [DOI: 10.1016/j.devcel.2018.05.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 03/17/2018] [Accepted: 08/27/2018] [Indexed: 01/01/2023]
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32
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Katz B, Minke B. The Drosophila light-activated TRP and TRPL channels - Targets of the phosphoinositide signaling cascade. Prog Retin Eye Res 2018; 66:200-219. [DOI: 10.1016/j.preteyeres.2018.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/29/2018] [Accepted: 05/02/2018] [Indexed: 01/28/2023]
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Cordero-Morales JF, Vásquez V. How lipids contribute to ion channel function, a fat perspective on direct and indirect interactions. Curr Opin Struct Biol 2018; 51:92-98. [PMID: 29602157 PMCID: PMC6162190 DOI: 10.1016/j.sbi.2018.03.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/07/2018] [Accepted: 03/15/2018] [Indexed: 11/30/2022]
Abstract
Membrane lipid composition and remodeling influence the function of ion channels. Polyunsaturated fatty acids (PUFAs) and their derivatives modulate ion channel function; whether this effect occurs directly by binding to the protein or indirectly through alteration of membranes' mechanical properties has been difficult to distinguish. There are a large number of studies addressing the effect of fatty acids; recent structural and functional analyses have identified binding sites and provided further evidence for the role of the plasma membrane in ion channel function. Here, we review cation channels that do not share a common topology or lipid-binding signature sequence, but for which there are recent compelling data that support both direct and indirect modulation by PUFAs or their derivatives.
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Affiliation(s)
- Julio F Cordero-Morales
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Valeria Vásquez
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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Ridone P, Grage SL, Patkunarajah A, Battle AR, Ulrich AS, Martinac B. "Force-from-lipids" gating of mechanosensitive channels modulated by PUFAs. J Mech Behav Biomed Mater 2017; 79:158-167. [PMID: 29304430 DOI: 10.1016/j.jmbbm.2017.12.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 12/20/2017] [Accepted: 12/22/2017] [Indexed: 12/15/2022]
Abstract
The level of fatty acid saturation in phospholipids is a crucial determinant of the biophysical properties of the lipid bilayer. Integral membrane proteins are sensitive to changes of their bilayer environment such that their activities and localization can be profoundly affected. When incorporated into phospholipids of mammalian cells, poly-unsaturated fatty acids (PUFAs) determine the mechanical properties of the bilayer thereby affecting several membrane-associated functions such as endo- and exo-cytosis and ion channel/membrane receptor signalling cascades. In order to understand how membrane tension is propagated through poly-unsaturated bilayers, we characterized the effect of lipid saturation on liposome reconstituted MscS and MscL, the two bacterial mechanosensitive ion channels that have for many years served as models of ion- channel-mediated mechanotransduction. The combination of NMR and patch clamp experiments in this study demonstrate that bilayer thinning is the main responsible factor for the modulation of the MscL threshold of activation while a change in transbilayer pressure profile is indicated as the main factor behind the observed modulation of the MscS kinetics. Together, our data offer a novel insight into how the structural shape differences between the two types of mechanosensitive channels determine their differential modulation by poly-unsaturated phospholipids and thus lay the foundation for future functional studies of eukaryotic ion channels involved in the physiology of mechanosensory transduction processes in mammalian cells. SUMMARY Mechanosensitive channels MscL and MscS are differentially modulated by poly-unsaturated fatty acids in lipid bilayers. MscL becomes sensitized because of increased hydrophobic mismatch while MscS open state is stabilized due to changes in the bilayer lateral pressure profile determined by NMR.
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Affiliation(s)
- Pietro Ridone
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Stephan L Grage
- Institute for Biological Interfaces IBG-2, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Amrutha Patkunarajah
- School of Medical Sciences, University of New South Wales, Kensington, Sydney 2052, Australia
| | - Andrew R Battle
- Translational Research Institute (TRI) and Institute of Health and Biomedical Innovation (IHBI), School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia
| | - Anne S Ulrich
- Institute for Biological Interfaces IBG-2, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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35
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Abstract
PURPOSE OF REVIEW Reception and transmission of signals across the plasma membrane has been a function generally attributed to transmembrane proteins. In the last 3 years, however, a growing number of reports have further acknowledged important contributions played by membrane lipids in the process of signal transduction. RECENT FINDINGS In particular, the constituency of membrane lipids can regulate how proteins with SH2 domains and molecules like K-Ras expose their catalytic domains to the cytosol and interact with effectors and second messengers. Recent reports have also shown that the degree of saturation of phospholipids can reduce the activation of certain G-protein-coupled receptors, and signaling downstream to Toll-like receptor 4 with consequences to nuclear factor kappa B activation and inflammation. Levels of specific gangliosides in the membrane were reported to activate integrins in a cell-autonomous manner affecting tumor cell migration. Furthermore, high resolution of the association of cholesterol with the smoothened receptor has clarified its participation in sonic hedgehog signaling. These are some of the key advancements that have further propelled our understanding of the broad versatile contributions of membrane lipids in signal transduction. SUMMARY As we gain definitive detail regarding the impact of lipid-protein interactions and their consequences to cell function, the options for therapeutic targeting expand with the possibility of greater specificity.
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Affiliation(s)
- Hannah Sunshine
- Molecular, Cellular and Integrative Physiology Graduate Program, UCLA
| | - M. Luisa Iruela-Arispe
- Departments of Molecular, Cell and Developmental Biology, UCLA, Los Angeles, California 90095
- Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
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36
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Caires R, Sierra-Valdez FJ, Millet JR, Herwig JD, Roan E, Vásquez V, Cordero-Morales JF. Omega-3 Fatty Acids Modulate TRPV4 Function through Plasma Membrane Remodeling. Cell Rep 2017; 21:246-258. [DOI: 10.1016/j.celrep.2017.09.029] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 07/18/2017] [Accepted: 09/07/2017] [Indexed: 12/26/2022] Open
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Traynor-Kaplan A, Kruse M, Dickson EJ, Dai G, Vivas O, Yu H, Whittington D, Hille B. Fatty-acyl chain profiles of cellular phosphoinositides. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:513-522. [PMID: 28189644 PMCID: PMC5392126 DOI: 10.1016/j.bbalip.2017.02.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/31/2017] [Accepted: 02/07/2017] [Indexed: 12/24/2022]
Abstract
Phosphoinositides are rapidly turning-over phospholipids that play key roles in intracellular signaling and modulation of membrane effectors. Through technical refinements we have improved sensitivity in the analysis of the phosphoinositide PI, PIP, and PIP2 pools from living cells using mass spectrometry. This has permitted further resolution in phosphoinositide lipidomics from cell cultures and small samples of tissue. The technique includes butanol extraction, derivatization of the lipids, post-column infusion of sodium to stabilize formation of sodiated adducts, and electrospray ionization mass spectrometry in multiple reaction monitoring mode, achieving a detection limit of 20pg. We describe the spectrum of fatty-acyl chains in the cellular phosphoinositides. Consistent with previous work in other mammalian primary cells, the 38:4 fatty-acyl chains dominate in the phosphoinositides of the pineal gland and of superior cervical ganglia, and many additional fatty acid combinations are found at low abundance. However, Chinese hamster ovary cells and human embryonic kidney cells (tsA201) in culture have different fatty-acyl chain profiles that change with growth state. Their 38:4 lipids lose their dominance as cultures approach confluence. The method has good time resolution and follows well the depletion in <20s of both PIP2 and PIP that results from strong activation of Gq-coupled receptors. The receptor-activated phospholipase C exhibits no substrate selectivity among the various fatty-acyl chain combinations.
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Affiliation(s)
- Alexis Traynor-Kaplan
- ATK Innovation, Analytics and Discovery, North Bend, WA 98045, USA; Department of Medicine/Gastroenterology, University of Washington School of Medicine, Seattle, WA, USA.
| | - Martin Kruse
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, USA
| | - Eamonn J Dickson
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, USA
| | - Gucan Dai
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, USA
| | - Oscar Vivas
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, USA
| | - Haijie Yu
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, USA
| | - Dale Whittington
- Department of Medicinal Chemistry, University of Washington School of Medicine, Seattle, WA, USA
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, USA
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38
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Peregrim I. Why we age — a new evolutionary view. Biologia (Bratisl) 2017. [DOI: 10.1515/biolog-2017-0064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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39
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Ciardo MG, Ferrer-Montiel A. Lipids as central modulators of sensory TRP channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1615-1628. [PMID: 28432033 DOI: 10.1016/j.bbamem.2017.04.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/13/2017] [Accepted: 04/15/2017] [Indexed: 12/13/2022]
Abstract
The transient receptor potential (TRP) ion channel family is involved in a diversity of physiological processes including sensory and homeostatic functions, as well as muscle contraction and vasomotor control. Their dysfunction contributes to the etiology of several diseases, being validated as therapeutic targets. These ion channels may be activated by physical or chemical stimuli and their function is highly influenced by signaling molecules activated by extracellular signals. Notably, as integral membrane proteins, lipid molecules also modulate their membrane location and function either by direct interaction with the channel structure or by modulating the physico-chemical properties of the cellular membrane. This lipid-based modulatory effect is being considered an alternative and promising approach to regulate TRP channel dysfunction in diseases. Here, we review the current progress in this exciting field highlighting a complex channel regulation by a large diversity of lipid molecules and suggesting some diseases that may benefit from a membrane lipid therapy. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
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Affiliation(s)
| | - Antonio Ferrer-Montiel
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Av. De la Universidad s/n, Elche, Spain.
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40
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The Phosphorylation State of the Drosophila TRP Channel Modulates the Frequency Response to Oscillating Light In Vivo. J Neurosci 2017; 37:4213-4224. [PMID: 28314815 DOI: 10.1523/jneurosci.3670-16.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/13/2017] [Accepted: 02/28/2017] [Indexed: 11/21/2022] Open
Abstract
Drosophila photoreceptors respond to oscillating light of high frequency (∼100 Hz), while the detected maximal frequency is modulated by the light rearing conditions, thus enabling high sensitivity to light and high temporal resolution. However, the molecular basis for this adaptive process is unclear. Here, we report that dephosphorylation of the light-activated transient receptor potential (TRP) ion channel at S936 is a fast, graded, light-dependent, and Ca2+-dependent process that is partially modulated by the rhodopsin phosphatase retinal degeneration C (RDGC). Electroretinogram measurements of the frequency response to oscillating lights in vivo revealed that dark-reared flies expressing wild-type TRP exhibited a detection limit of oscillating light at relatively low frequencies, which was shifted to higher frequencies upon light adaptation. Strikingly, preventing phosphorylation of the S936-TRP site by alanine substitution in transgenic Drosophila (trpS936A ) abolished the difference in frequency response between dark-adapted and light-adapted flies, resulting in high-frequency response also in dark-adapted flies. In contrast, inserting a phosphomimetic mutation by substituting the S936-TRP site to aspartic acid (trpS936D ) set the frequency response of light-adapted flies to low frequencies typical of dark-adapted flies. Light-adapted rdgC mutant flies showed relatively high S936-TRP phosphorylation levels and light-dark phosphorylation dynamics. These findings suggest that RDGC is one but not the only phosphatase involved in pS936-TRP dephosphorylation. Together, this study indicates that TRP channel dephosphorylation is a regulatory process that affects the detection limit of oscillating light according to the light rearing condition, thus adjusting dynamic processing of visual information under varying light conditions.SIGNIFICANCE STATEMENTDrosophila photoreceptors exhibit high temporal resolution as manifested in frequency response to oscillating light of high frequency (≤∼100 Hz). Light rearing conditions modulate the maximal frequency detected by photoreceptors, thus enabling them to maintain high sensitivity to light and high temporal resolution. However, the precise mechanisms for this process are not fully understood. Here, we show by combination of biochemistry and in vivo electrophysiology that transient receptor potential (TRP) channel dephosphorylation at a specific site is a fast, light-activated and Ca2+-dependent regulatory process. TRP dephosphorylation affects the detection limit of oscillating light according to the adaptation state of the photoreceptor cells by shifting the detection limit to higher frequencies upon light adaptation. This novel mechanism thus adjusts dynamic processing of visual information under varying light conditions.
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41
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Asteriti S, Liu CH, Hardie RC. Calcium signalling in Drosophila photoreceptors measured with GCaMP6f. Cell Calcium 2017; 65:40-51. [PMID: 28238353 PMCID: PMC5472182 DOI: 10.1016/j.ceca.2017.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/10/2017] [Accepted: 02/10/2017] [Indexed: 11/30/2022]
Abstract
Drosophila phototransduction is mediated by phospholipase C leading to activation of cation channels (TRP and TRPL) in the 30000 microvilli forming the light-absorbing rhabdomere. The channels mediate massive Ca2+ influx in response to light, but whether Ca2+ is released from internal stores remains controversial. We generated flies expressing GCaMP6f in their photoreceptors and measured Ca2+ signals from dissociated cells, as well as in vivo by imaging rhabdomeres in intact flies. In response to brief flashes, GCaMP6f signals had latencies of 10-25ms, reached 50% Fmax with ∼1200 effectively absorbed photons and saturated (ΔF/F0∼10-20) with 10000-30000 photons. In Ca2+ free bath, smaller (ΔF/F0 ∼4), long latency (∼200ms) light-induced Ca2+ rises were still detectable. These were unaffected in InsP3 receptor mutants, but virtually eliminated when Na+ was also omitted from the bath, or in trpl;trp mutants lacking light-sensitive channels. Ca2+ free rises were also eliminated in Na+/Ca2+ exchanger mutants, but greatly accelerated in flies over-expressing the exchanger. These results show that Ca2+ free rises are strictly dependent on Na+ influx and activity of the exchanger, suggesting they reflect re-equilibration of Na+/Ca2+ exchange across plasma or intracellular membranes following massive Na+ influx. Any tiny Ca2+ free rise remaining without exchanger activity was equivalent to <10nM (ΔF/F0 ∼0.1), and unlikely to play any role in phototransduction.
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Affiliation(s)
- Sabrina Asteriti
- Cambridge University, Department of Physiology Development and Neuroscience, Downing Street, Cambridge, CB2 3EG, UK
| | - Che-Hsiung Liu
- Cambridge University, Department of Physiology Development and Neuroscience, Downing Street, Cambridge, CB2 3EG, UK
| | - Roger C Hardie
- Cambridge University, Department of Physiology Development and Neuroscience, Downing Street, Cambridge, CB2 3EG, UK.
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42
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Abstract
Aggression is a universal social behavior important for the acquisition of food, mates, territory, and social status. Aggression in Drosophila is context-dependent and can thus be expected to involve inputs from multiple sensory modalities. Here, we use mechanical disruption and genetic approaches in Drosophila melanogaster to identify hearing as an important sensory modality in the context of intermale aggressive behavior. We demonstrate that neuronal silencing and targeted knockdown of hearing genes in the fly's auditory organ elicit abnormal aggression. Further, we show that exposure to courtship or aggression song has opposite effects on aggression. Our data define the importance of hearing in the control of Drosophila intermale aggression and open perspectives to decipher how hearing and other sensory modalities are integrated at the neural circuit level.
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43
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Juusola M, Dau A, Zheng L, Rien D. Electrophysiological Method for Recording Intracellular Voltage Responses of Drosophila Photoreceptors and Interneurons to Light Stimuli In Vivo. J Vis Exp 2016. [PMID: 27403647 PMCID: PMC4993232 DOI: 10.3791/54142] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Voltage responses of insect photoreceptors and visual interneurons can be accurately recorded with conventional sharp microelectrodes. The method described here enables the investigator to measure long-lasting (from minutes to hours) high-quality intracellular responses from single Drosophila R1-R6 photoreceptors and Large Monopolar Cells (LMCs) to light stimuli. Because the recording system has low noise, it can be used to study variability among individual cells in the fly eye, and how their outputs reflect the physical properties of the visual environment. We outline all key steps in performing this technique. The basic steps in constructing an appropriate electrophysiology set-up for recording, such as design and selection of the experimental equipment are described. We also explain how to prepare for recording by making appropriate (sharp) recording and (blunt) reference electrodes. Details are given on how to fix an intact fly in a bespoke fly-holder, prepare a small window in its eye and insert a recording electrode through this hole with minimal damage. We explain how to localize the center of a cell's receptive field, dark- or light-adapt the studied cell, and to record its voltage responses to dynamic light stimuli. Finally, we describe the criteria for stable normal recordings, show characteristic high-quality voltage responses of individual cells to different light stimuli, and briefly define how to quantify their signaling performance. Many aspects of the method are technically challenging and require practice and patience to master. But once learned and optimized for the investigator's experimental objectives, it grants outstanding in vivo neurophysiological data.
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Affiliation(s)
- Mikko Juusola
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University; Department of Biomedical Science, The University of Sheffield;
| | - An Dau
- Department of Biomedical Science, The University of Sheffield
| | - Lei Zheng
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University
| | - Diana Rien
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University; Department of Biomedical Science, The University of Sheffield
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44
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Kolay S, Basu U, Raghu P. Control of diverse subcellular processes by a single multi-functional lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. Biochem J 2016; 473:1681-92. [PMID: 27288030 PMCID: PMC6609453 DOI: 10.1042/bcj20160069] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/07/2016] [Indexed: 12/16/2022]
Abstract
Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a multi-functional lipid that regulates several essential subcellular processes in eukaryotic cells. In addition to its well-established function as a substrate for receptor-activated signalling at the plasma membrane (PM), it is now recognized that distinct PI(4,5)P2 pools are present at other organelle membranes. However, a long-standing question that remains unresolved is the mechanism by which a single lipid species, with an invariant functional head group, delivers numerous functions without loss of fidelity. In the present review, we summarize studies that have examined the molecular processes that shape the repertoire of PI(4,5)P2 pools in diverse eukaryotes. Collectively, these studies indicate a conserved role for lipid kinase isoforms in generating functionally distinct pools of PI(4,5)P2 in diverse metazoan species. The sophistication underlying the regulation of multiple functions by PI(4,5)P2 is also shaped by mechanisms that regulate its availability to enzymes involved in its metabolism as well as molecular processes that control its diffusion at nanoscales in the PM. Collectively, these mechanisms ensure the specificity of PI(4,5)P2 mediated signalling at eukaryotic membranes.
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Affiliation(s)
- Sourav Kolay
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India
| | - Urbashi Basu
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Padinjat Raghu
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
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45
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Weijers RNM. Membrane flexibility, free fatty acids, and the onset of vascular and neurological lesions in type 2 diabetes. J Diabetes Metab Disord 2016; 15:13. [PMID: 27123439 PMCID: PMC4847252 DOI: 10.1186/s40200-016-0235-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 04/10/2016] [Indexed: 12/13/2022]
Abstract
Free fatty acids released from human adipose tissue contain a limited amount of non-esterified poly-cis-unsaturated fatty acids. In cases of elevated plasma free fatty acids, this condition ultimately leads to a shift from unsaturated to saturated fatty-acyl chains in membrane phospholipids. Because this shift promotes the physical attractive van der Waals interactions between phospholipid acyl chains, it increases stiffness of both erythrocyte and endothelial membranes, which causes a reduction in both insulin-independent and insulin-dependent Class 1 glucose transporters, a reduction in cell membrane functionality, and a decreased microcirculatory blood flow which results in tissue hypoxia. Against the background of these processes, we review recently published experimental phospholipid data obtained from Drosophila melanogaster and from human erythrocytes of controls and patients with type 2 diabetes, with and without retinopathy, along the way free fatty acids interfere with eye and kidney function in patients with type 2 diabetes and give rise to endoplasmic reticulum stress, reduced insulin sensitivity, and ischemia.
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Affiliation(s)
- Rob N M Weijers
- Teaching Hospital, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands
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46
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Barelli H, Antonny B. Lipid unsaturation and organelle dynamics. Curr Opin Cell Biol 2016; 41:25-32. [PMID: 27062546 DOI: 10.1016/j.ceb.2016.03.012] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/16/2016] [Accepted: 03/23/2016] [Indexed: 12/13/2022]
Abstract
The number of double bonds (=unsaturation) in the acyl chains of phospholipids (PL) influences the physical properties of cellular membranes. Here, we discuss disparate molecular processes, including vesicle budding, ion channel opening, and lipoprotein formation, which are greatly facilitated by PL polyunsaturation in membranes. Experimental and computer-based approaches for the structure and dynamics of PL suggest a common cause for these effects: the ability of the polyunsaturated acyl chain of PL to extend or bent along the membrane normal according to various constraints, thereby enabling a third dimension of motion in a structure that is essentially a 2D fluid.
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Affiliation(s)
- Hélène Barelli
- Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France.
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France.
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47
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Weijers RNM. Comment on Dornellas et al., Deleterious effects of lard-enriched diet on tissues fatty acids composition and hypothalamic insulin actions, Prostaglandins, Leukot. Essent. Fat. Acids., 102-103 (2015) 21-29. Prostaglandins Leukot Essent Fatty Acids 2016; 107:22-3. [PMID: 27033422 DOI: 10.1016/j.plefa.2016.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 03/01/2016] [Indexed: 11/20/2022]
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48
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Antonny B, Vanni S, Shindou H, Ferreira T. From zero to six double bonds: phospholipid unsaturation and organelle function. Trends Cell Biol 2015; 25:427-36. [DOI: 10.1016/j.tcb.2015.03.004] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/19/2015] [Accepted: 03/23/2015] [Indexed: 01/21/2023]
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