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Tosh N, Watson J, Lukas D, Tremewan R, Beard J, Galloway G, Haselhorst T, Young R, Crompton D, Mountford C. Two-dimensional correlated spectroscopy records reduced neurotransmission in blast-exposed artillery soldiers after live fire training. NMR IN BIOMEDICINE 2023:e4934. [PMID: 36940008 DOI: 10.1002/nbm.4934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/17/2023] [Accepted: 03/12/2023] [Indexed: 06/18/2023]
Abstract
There is a requirement for an objective method to determine a safe level of low-level military occupational blast, having recognised it can lead to neurological damage. The purpose of the current study was to evaluate the effect of artillery firing training on the neurochemistry of frontline soldiers using two-dimensional (2D) COrrelated SpectroscopY (2D COSY) in a 3-T clinical MR scanner. Ten men considered to be of sound health were evaluated before and after a week-long live firing exercise in two ways. Prior to the live fire exercise, all participants were screened by a clinical psychologist using a combination of clinical interviews and psychometric tests, and were then scanned with 3-T MRI. The protocols included T1- and T2-weighted images for diagnostic reporting and anatomical localisation and 2D COSY to record any neurochemical effects from the firing. No changes to the structural MRI were recorded. Nine substantive and statistically significant changes in the neurochemistry were recorded as a consequence of firing training. Glutamine and glutamate, glutathione, and two of the seven fucose-α (1-2)-glycans were significantly increased. N-acetyl aspartate, myo-inositol + creatine, and glycerol were also increased. Significant decreases were recorded for the glutathione cysteine moiety and tentatively assigned glycan with a 1-6 linkage (F2: 4.00, F1: 1.31 ppm). These molecules are part of three neurochemical pathways at the terminus of the neurons providing evidence of early markers of disruption to neurotransmission. Using this technology, the extent of deregulation can now be monitored for each frontline defender on a personalised basis. The capacity to monitor early a disruption in neurotransmitters, using the 2D COSY protocol, can observe the effect of firing and may be used to prevent or limit these events.
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Affiliation(s)
- Nathan Tosh
- Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
- Translational Research Institute, Woolloongabba, Queensland, Australia
- Radiology Department, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia
| | - Julia Watson
- Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
- Translational Research Institute, Woolloongabba, Queensland, Australia
- Radiology Department, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia
| | - Darren Lukas
- Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Rosanna Tremewan
- Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Jason Beard
- Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Graham Galloway
- Translational Research Institute, Woolloongabba, Queensland, Australia
| | | | - Ross Young
- Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - David Crompton
- Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
- Glycomics Institute, Southport, Queensland, Australia
| | - Carolyn Mountford
- Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
- Translational Research Institute, Woolloongabba, Queensland, Australia
- Radiology Department, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia
- Glycomics Institute, Southport, Queensland, Australia
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2
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Suliman M, Case KC, Schmidtke MW, Lazcano P, Onu CJ, Greenberg ML. Inositol depletion regulates phospholipid metabolism and activates stress signaling in HEK293T cells. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159137. [PMID: 35247568 DOI: 10.1016/j.bbalip.2022.159137] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/17/2022] [Accepted: 02/23/2022] [Indexed: 12/13/2022]
Abstract
Inositol plays a significant role in cellular function and signaling. Studies in yeast have demonstrated an "inositol-less death" phenotype, suggesting that inositol is an essential metabolite. In yeast, inositol synthesis is highly regulated, and inositol levels have been shown to be a major metabolic regulator, with its abundance affecting the expression of hundreds of genes. Abnormalities in inositol metabolism have been associated with several human disorders. Despite its importance, very little is known about the regulation of inositol synthesis and the pathways regulated by inositol in human cells. The current study aimed to address this knowledge gap. Knockout of ISYNA1 (encoding myo-inositol-3-P synthase 1) in HEK293T cells generated a human cell line that is deficient in de novo inositol synthesis. ISYNA1-KO cells exhibited inositol-less death when deprived of inositol. Lipidomic analysis identified inositol depletion as a global regulator of phospholipid levels in human cells, including downregulation of phosphatidylinositol (PI) and upregulation of the phosphatidylglycerol (PG)/cardiolipin (CL) branch of phospholipid metabolism. RNA-Seq analysis revealed that inositol depletion induced substantial changes in the expression of genes involved in cell signaling, including extracellular signal-regulated kinase (ERK), and genes controlling amino acid transport and protein processing in the endoplasmic reticulum (ER). This study provides the first in-depth characterization of the effects of inositol depletion on phospholipid metabolism and gene expression in human cells, establishing an essential role for inositol in maintaining cell viability and regulating cell signaling and metabolism.
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Affiliation(s)
- Mahmoud Suliman
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States of America
| | - Kendall C Case
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States of America
| | - Michael W Schmidtke
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States of America
| | - Pablo Lazcano
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States of America
| | - Chisom J Onu
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States of America
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States of America.
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3
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Suliman M, Schmidtke MW, Greenberg ML. The Role of the UPR Pathway in the Pathophysiology and Treatment of Bipolar Disorder. Front Cell Neurosci 2021; 15:735622. [PMID: 34531727 PMCID: PMC8439382 DOI: 10.3389/fncel.2021.735622] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/09/2021] [Indexed: 11/13/2022] Open
Abstract
Bipolar disorder (BD) is a mood disorder that affects millions worldwide and is associated with severe mood swings between mania and depression. The mood stabilizers valproate (VPA) and lithium (Li) are among the main drugs that are used to treat BD patients. However, these drugs are not effective for all patients and cause serious side effects. Therefore, better drugs are needed to treat BD patients. The main barrier to developing new drugs is the lack of knowledge about the therapeutic mechanism of currently available drugs. Several hypotheses have been proposed for the mechanism of action of mood stabilizers. However, it is still not known how they act to alleviate both mania and depression. The pathology of BD is characterized by mitochondrial dysfunction, oxidative stress, and abnormalities in calcium signaling. A deficiency in the unfolded protein response (UPR) pathway may be a shared mechanism that leads to these cellular dysfunctions. This is supported by reported abnormalities in the UPR pathway in lymphoblasts from BD patients. Additionally, studies have demonstrated that mood stabilizers alter the expression of several UPR target genes in mouse and human neuronal cells. In this review, we outline a new perspective wherein mood stabilizers exert their therapeutic mechanism by activating the UPR. Furthermore, we discuss UPR abnormalities in BD patients and suggest future research directions to resolve discrepancies in the literature.
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Affiliation(s)
- Mahmoud Suliman
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Michael W Schmidtke
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
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4
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Case KC, Salsaa M, Yu W, Greenberg ML. Regulation of Inositol Biosynthesis: Balancing Health and Pathophysiology. Handb Exp Pharmacol 2020; 259:221-260. [PMID: 30591968 DOI: 10.1007/164_2018_181] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Inositol is the precursor for all inositol compounds and is essential for viability of eukaryotic cells. Numerous cellular processes and signaling functions are dependent on inositol compounds, and perturbation of their synthesis leads to a wide range of human diseases. Although considerable research has been directed at understanding the function of inositol compounds, especially phosphoinositides and inositol phosphates, a focus on regulatory and homeostatic mechanisms controlling inositol biosynthesis has been largely neglected. Consequently, little is known about how synthesis of inositol is regulated in human cells. Identifying physiological regulators of inositol synthesis and elucidating the molecular mechanisms that regulate inositol synthesis will contribute fundamental insight into cellular processes that are mediated by inositol compounds and will provide a foundation to understand numerous disease processes that result from perturbation of inositol homeostasis. In addition, elucidating the mechanisms of action of inositol-depleting drugs may suggest new strategies for the design of second-generation pharmaceuticals to treat psychiatric disorders and other illnesses.
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Affiliation(s)
- Kendall C Case
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Michael Salsaa
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Wenxi Yu
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA.
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5
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Ma A, Cui W, Wang X, Zhang W, Liu Z, Zhang J, Zhao T. Osmoregulation by the myo-inositol biosynthesis pathway in turbot Scophthalmus maximus and its regulation by anabolite and c-Myc. Comp Biochem Physiol A Mol Integr Physiol 2019; 242:110636. [PMID: 31846703 DOI: 10.1016/j.cbpa.2019.110636] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 12/08/2019] [Accepted: 12/12/2019] [Indexed: 12/12/2022]
Abstract
The induction of the myo-inositol biosynthesis (MIB) pathway in euryhaline fishes is an important component of the cellular response to osmotic challenge. The MIPS and IMPA1 genes were sequenced in turbot and found to be highly conserved in phylogenetic evolution, especially within the fish species tested. Under salinity stress in turbot, both MIPS and IMPA1 showed adaptive expression, a turning point in the level of expression occurred at 12 h in all tissues tested. We performed an RNAi assay mediated by long fragment dsRNA prepared by transcription in vitro. The findings demonstrated that knockdown of the MIB pathway weakened the function of gill osmotic regulation, and may induce a genetic compensation response in the kidney and gill to maintain physiological function. Even though the gill and kidney conducted stress reactions or compensatory responses to salinity stress, this inadequately addressed the consequences of MIB knockdown. Therefore, the survival time of turbot under salinity stress after knockdown was obviously less than that under seawater, especially under low salt stress. Pearson's correlation analysis between gene expression and dietary myo-inositol concentration indicated that the MIB pathway had a remarkable negative feedback control, and the dynamic equilibrium mediated by negative feedback on the MIB pathway played a crucial role in osmoregulation in turbot. An RNAi assay with c-Myc in vivo and the use of a c-Myc inhibitor (10058-F4) in vitro demonstrated that c-Myc was likely to positively regulate the MIB pathway in turbot.
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Affiliation(s)
- Aijun Ma
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shandong Key Laboratory of Marine Fisheries Biotechnology and Genetic Breeding, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
| | - Wenxiao Cui
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shandong Key Laboratory of Marine Fisheries Biotechnology and Genetic Breeding, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; College of Fisheries and Life Science, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China
| | - Xinan Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shandong Key Laboratory of Marine Fisheries Biotechnology and Genetic Breeding, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; College of Fisheries and Life Science, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China
| | - Wei Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shandong Key Laboratory of Marine Fisheries Biotechnology and Genetic Breeding, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Zhifeng Liu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shandong Key Laboratory of Marine Fisheries Biotechnology and Genetic Breeding, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Jinsheng Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shandong Key Laboratory of Marine Fisheries Biotechnology and Genetic Breeding, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; College of Fisheries and Life Science, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China
| | - Tingting Zhao
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shandong Key Laboratory of Marine Fisheries Biotechnology and Genetic Breeding, Qingdao Key Laboratory for Marine Fish Breeding and Biotechnology, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; College of Fisheries and Life Science, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China
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6
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Carreira AC, Santos TC, Lone MA, Zupančič E, Lloyd-Evans E, de Almeida RFM, Hornemann T, Silva LC. Mammalian sphingoid bases: Biophysical, physiological and pathological properties. Prog Lipid Res 2019:100995. [PMID: 31445071 DOI: 10.1016/j.plipres.2019.100995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 05/17/2019] [Accepted: 05/20/2019] [Indexed: 12/19/2022]
Abstract
Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease.
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Affiliation(s)
- A C Carreira
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal; Sir Martin Evans Building, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - T C Santos
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Centro de Química-Física Molecular - Institute of Nanoscience and Nanotechnology (CQFM-IN) and IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal; Institute for Clinical Chemistry, University Hospital Zurich, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - M A Lone
- Institute for Clinical Chemistry, University Hospital Zurich, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - E Zupančič
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - E Lloyd-Evans
- Sir Martin Evans Building, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - R F M de Almeida
- Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal
| | - T Hornemann
- Institute for Clinical Chemistry, University Hospital Zurich, Switzerland; Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - L C Silva
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Centro de Química-Física Molecular - Institute of Nanoscience and Nanotechnology (CQFM-IN) and IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
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7
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Carreira AC, Santos TC, Lone MA, Zupančič E, Lloyd-Evans E, de Almeida RFM, Hornemann T, Silva LC. Mammalian sphingoid bases: Biophysical, physiological and pathological properties. Prog Lipid Res 2019; 75:100988. [PMID: 31132366 DOI: 10.1016/j.plipres.2019.100988] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 12/11/2022]
Abstract
Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules, and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease.
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Affiliation(s)
- A C Carreira
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa 1649-003, Portugal; Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, Lisboa 1749-016, Portugal; Sir Martin Evans Building, School of Biosciences, Cardiff University, Cardiff, UK
| | - T C Santos
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa 1649-003, Portugal; Centro de Química-Física Molecular - Institute of Nanoscience and Nanotechnology (CQFM-IN), IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal; Institute for Clinical Chemistry, University Hospital Zurich, Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - M A Lone
- Institute for Clinical Chemistry, University Hospital Zurich, Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - E Zupančič
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa 1649-003, Portugal
| | - E Lloyd-Evans
- Sir Martin Evans Building, School of Biosciences, Cardiff University, Cardiff, UK
| | - R F M de Almeida
- Centro de Química e Bioquímica (CQB) e Centro de Química Estrutural (CQE), Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, Lisboa 1749-016, Portugal
| | - T Hornemann
- Institute for Clinical Chemistry, University Hospital Zurich, Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland
| | - L C Silva
- iMed.ULisboa - Research Institute for Medicines, Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, Lisboa 1649-003, Portugal; Centro de Química-Física Molecular - Institute of Nanoscience and Nanotechnology (CQFM-IN), IBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
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8
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Disruption of INOS, a Gene Encoding myo-Inositol Phosphate Synthase, Causes Male Sterility in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2018; 8:2913-2922. [PMID: 29991509 PMCID: PMC6118315 DOI: 10.1534/g3.118.200403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Inositol is a precursor for the phospholipid membrane component phosphatidylinositol (PI), involved in signal transduction pathways, endoplasmic reticulum stress, and osmoregulation. Alterations of inositol metabolism have been implicated in human reproductive issues, the therapeutic effects of drugs used to treat epilepsy and bipolar disorder, spinal cord defects, and diseases including diabetes and Alzheimer’s. The sole known inositol synthetic enzyme is myo-inositol synthase (MIPS), and the homolog in Drosophilia melanogaster is encoded by the Inos gene. Three identical deletion strains (inosΔDF/CyO) were constructed, confirmed by PCR and sequencing, and homozygotes (inosΔDF/inosΔDF) were shown to lack the transcript encoding the MIPS enzyme. Without inositol, homozygous inosΔDF deletion fertilized eggs develop only to the first-instar larval stage. When transferred as pupae to food without inositol, however, inosΔDF homozygotes die significantly sooner than wild-type flies. Even with dietary inositol the homozygous inosΔDF males are sterile. An inos allele, with a P-element inserted into the first intron, fails to complement this male sterile phenotype. An additional copy of the Inos gene inserted into another chromosome rescues all the phenotypes. These genetic and phenotypic analyses establish D. melanogaster as an excellent model organism in which to examine the role of inositol synthesis in development and reproduction.
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9
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Salsaa M, Case K, Greenberg ML. Orchestrating phospholipid biosynthesis: Phosphatidic acid conducts and Opi1p performs. J Biol Chem 2017; 292:18729-18730. [PMID: 29127205 DOI: 10.1074/jbc.h117.809970] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphatidic acid (PA) and the conserved integral ER membrane protein Scs2p regulate localization of the transcriptional repressor Opi1p, which controls expression of phospholipid biosynthesis genes, but the mechanisms conducting Opi1p localization are not fully understood. A new study suggests the existence of a distinct pool of PA in the ER that is required for regulation of Opi1p localization and thus phospholipid metabolism in yeast.
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Affiliation(s)
- Michael Salsaa
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Kendall Case
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
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10
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Jadhav S, Russo S, Cowart LA, Greenberg ML. Inositol Depletion Induced by Acute Treatment of the Bipolar Disorder Drug Valproate Increases Levels of Phytosphingosine. J Biol Chem 2017; 292:4953-4959. [PMID: 28100786 DOI: 10.1074/jbc.m117.775460] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 01/17/2017] [Indexed: 12/13/2022] Open
Abstract
Bipolar disorder (BD) is a severe psychiatric illness affecting ∼1% of the world population. Valproate (VPA) and lithium, widely used for the treatment of BD, are not universally effective. These drugs have been shown to cause inositol depletion, but translating this observation to a specific therapeutic mechanism has been difficult, hampering the development of more effective therapies. We have shown previously in yeast that chronic VPA treatment induces the unfolded protein response due to increasing ceramide levels. To gain insight into the mechanisms activated during acute VPA treatment, we performed a genome-wide expression study in yeast treated with VPA for 30 min. We observed increased mRNA and protein levels of RSB1, which encodes an exporter of long chain bases dihydrosphingosine (DHS) and phytosphingosine (PHS), and further saw that VPA increased sensitivity of an rsb1Δ mutant to PHS, suggesting that VPA increases long chain base levels. Consistent with this, PHS levels were elevated in wild type and, to a greater extent, in rsb1Δ cells. Expression of ORM genes (negative regulators of PHS synthesis) and of fatty acid elongase genes FEN1 and SUR4 were decreased, and expression of YOR1 (exporter of PHS-1P) and DPL1 (lyase that degrades DHS-1P and PHS-1P) was increased. These effects were more pronounced in medium lacking inositol, and were mirrored by inositol starvation of an ino1Δ mutant. These findings provide a metabolic explanation as to how VPA-mediated inositol depletion causes increased synthesis of PHS and further support the therapeutic relevance of inositol depletion as a bipolar disorder treatment.
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Affiliation(s)
- Shyamalagauri Jadhav
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Sarah Russo
- the Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, and.,the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29425
| | - L Ashley Cowart
- the Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, and.,the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29425
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202,
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11
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Jadhav S, Russo S, Cottier S, Schneiter R, Cowart A, Greenberg ML. Valproate Induces the Unfolded Protein Response by Increasing Ceramide Levels. J Biol Chem 2016; 291:22253-22261. [PMID: 27590340 DOI: 10.1074/jbc.m116.752634] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Indexed: 11/06/2022] Open
Abstract
Bipolar disorder (BD), which is characterized by depression and mania, affects 1-2% of the world population. Current treatments are effective in only 40-60% of cases and cause severe side effects. Valproate (VPA) is one of the most widely used drugs for the treatment of BD, but the therapeutic mechanism of action of this drug is not understood. This knowledge gap has hampered the development of effective treatments. To identify candidate pathways affected by VPA, we performed a genome-wide expression analysis in yeast cells grown in the presence or absence of the drug. VPA caused up-regulation of FEN1 and SUR4, encoding fatty acid elongases that catalyze the synthesis of very long chain fatty acids (C24 to C26) required for ceramide synthesis. Interestingly, fen1Δ and sur4Δ mutants exhibited VPA sensitivity. In agreement with increased fatty acid elongase gene expression, VPA increased levels of phytoceramide, especially those containing C24-C26 fatty acids. Consistent with an increase in ceramide, VPA decreased the expression of amino acid transporters, increased the expression of ER chaperones, and activated the unfolded protein response element (UPRE), suggesting that VPA induces the UPR pathway. These effects were rescued by supplementation of inositol and similarly observed in inositol-starved ino1Δ cells. Starvation of ino1Δ cells increased expression of FEN1 and SUR4, increased ceramide levels, decreased expression of nutrient transporters, and induced the UPR. These findings suggest that VPA-mediated inositol depletion induces the UPR by increasing the de novo synthesis of ceramide.
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Affiliation(s)
- Shyamalagauri Jadhav
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Sarah Russo
- the Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29401, and
| | - Stéphanie Cottier
- the Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Roger Schneiter
- the Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Ashley Cowart
- the Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, the Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29401, and
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202,
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Bizzarri M, Fuso A, Dinicola S, Cucina A, Bevilacqua A. Pharmacodynamics and pharmacokinetics of inositol(s) in health and disease. Expert Opin Drug Metab Toxicol 2016; 12:1181-96. [PMID: 27351907 DOI: 10.1080/17425255.2016.1206887] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Inositol and its derivatives comprise a huge field of biology. Myo-inositol is not only a prominent component of membrane-incorporated phosphatidylinositol, but participates in its free form, with its isomers or its phosphate derivatives, to a multitude of cellular processes, including ion channel permeability, metabolic homeostasis, mRNA export and translation, cytoskeleton remodeling, stress response. AREAS COVERED Bioavailability, safety, uptake and metabolism of inositol is discussed emphasizing the complexity of interconnected pathways leading to phosphoinositides, inositol phosphates and more complex molecules, like glycosyl-phosphatidylinositols. EXPERT OPINION Besides being a structural element, myo-inositol exerts unexpected functions, mostly unknown. However, several reports indicate that inositol plays a key role during phenotypic transitions and developmental phases. Furthermore, dysfunctions in the regulation of inositol metabolism have been implicated in several chronic diseases. Clinical trials using inositol in pharmacological doses provide amazing results in the management of gynecological diseases, respiratory stress syndrome, Alzheimer's disease, metabolic syndrome, and cancer, for which conventional treatments are disappointing. However, despite the widespread studies carried out to identify inositol-based effects, no comprehensive understanding of inositol-based mechanisms has been achieved. An integrated metabolomics-genomic study to identify the cellular fate of therapeutically administered myo-inositol and its genomic/enzymatic targets is urgently warranted.
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Affiliation(s)
- Mariano Bizzarri
- a Department of Experimental Medicine , Sapienza University of Rome , Rome , Italy.,b Systems Biology Group Lab , Sapienza University of Rome , Rome , Italy
| | - Andrea Fuso
- b Systems Biology Group Lab , Sapienza University of Rome , Rome , Italy.,c European Center for Brain Research (CERC)/IRCCS Santa Lucia Foundation , Rome , Italy
| | - Simona Dinicola
- d Department of Clinical and Molecular Medicine , Sapienza Universityof Rome , Rome , Italy.,e Department of Surgery 'Pietro Valdoni' , Sapienza University of Rome , Rome , Italy
| | - Alessandra Cucina
- e Department of Surgery 'Pietro Valdoni' , Sapienza University of Rome , Rome , Italy.,f Azienda Policlinico Umberto I , Rome , Italy
| | - Arturo Bevilacqua
- g Department of Psychology, Section of Neuroscience , Sapienza University of Rome , Rome , Italy
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Kalujnaia S, Hazon N, Cramb G. Myo-inositol phosphate synthase expression in the European eel (Anguilla anguilla) and Nile tilapia (Oreochromis niloticus): effect of seawater acclimation. Am J Physiol Regul Integr Comp Physiol 2016; 311:R287-98. [PMID: 27252471 PMCID: PMC5008666 DOI: 10.1152/ajpregu.00056.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/25/2016] [Indexed: 11/29/2022]
Abstract
A single MIPS gene (Isyna1/Ino1) exists in eel and tilapia genomes with a single myo-d-inositol 3-phosphate synthase (MIPS) transcript identified in all eel tissues, although two MIPS spliced variants [termed MIPS(s) and MIPS(l)] are found in all tilapia tissues. The larger tilapia transcript [MIPS(l)] results from the inclusion of the 87-nucleotide intron between exons 5 and 6 in the genomic sequence. In most tilapia tissues, the MIPS(s) transcript exhibits much higher abundance (generally >10-fold) with the exception of white skeletal muscle and oocytes, in which the MIPS(l) transcript predominates. SW acclimation resulted in large (6- to 32-fold) increases in mRNA expression for both MIPS(s) and MIPS(l) in all tilapia tissues tested, whereas in the eel, changes in expression were limited to a more modest 2.5-fold increase and only in the kidney. Western blots identified a number of species- and tissue-specific immunoreactive MIPS proteins ranging from 40 to 67 kDa molecular weight. SW acclimation failed to affect the abundance of any immunoreactive protein in any tissue tested from the eel. However, a major 67-kDa immunoreactive protein (presumed to be MIPS) found in tilapia tissues exhibited 11- and 54-fold increases in expression in gill and fin samples from SW-acclimated fish. Immunohistochemical investigations revealed specific immunoreactivity in the gill, fin, skin, and intestine taken from only SW-acclimated tilapia. Immunofluorescence indicated that MIPS was expressed within gill chondrocytes and epithelial cells of the primary filaments, basal epithelial cell layers of the skin and fin, the cytosol of columnar intestinal epithelial and mucous cells, as well as unknown entero-endocrine-like cells.
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Affiliation(s)
- Svetlana Kalujnaia
- School of Medicine, University of St. Andrews, St. Andrews, United Kingdom; and
| | - Neil Hazon
- School of Biology, University of St. Andrews, St. Andrews, United Kingdom
| | - Gordon Cramb
- School of Medicine, University of St. Andrews, St. Andrews, United Kingdom; and
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14
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Yu W, Greenberg ML. Inositol depletion, GSK3 inhibition and bipolar disorder. FUTURE NEUROLOGY 2016; 11:135-148. [PMID: 29339929 DOI: 10.2217/fnl-2016-0003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/04/2016] [Indexed: 12/31/2022]
Abstract
Valproic acid and lithium are widely used to treat bipolar disorder, a severe illness characterized by cycles of mania and depression. However, their efficacy is limited, and treatment is often accompanied by serious side effects. The therapeutic mechanisms of these drugs are not understood, hampering the development of more effective treatments. Among the plethora of biochemical effects of the drugs, those that are common to both may be more related to therapeutic efficacy. Two common outcomes include inositol depletion and GSK3 inhibition, which have been proposed to explain the efficacy of both valproic acid and lithium. Here, we discuss the inositol depletion and GSK3 inhibition hypotheses, and introduce a unified model suggesting that inositol depletion and GSK3 inhibition are inter-related.
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Affiliation(s)
- Wenxi Yu
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Miriam L Greenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
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Yu W, Ye C, Greenberg ML. Inositol Hexakisphosphate Kinase 1 (IP6K1) Regulates Inositol Synthesis in Mammalian Cells. J Biol Chem 2016; 291:10437-44. [PMID: 26953345 DOI: 10.1074/jbc.m116.714816] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Indexed: 01/12/2023] Open
Abstract
myo-Inositol, the precursor of all inositol compounds, has pivotal roles in cell metabolism and signaling pathways. Although physiological studies indicate a strong correlation between abnormal intracellular inositol levels and neurological disorders, very little is known about the regulation of inositol synthesis in mammalian cells. In this study, we report that IP6K1, an inositol hexakisphosphate kinase that catalyzes the synthesis of inositol pyrophosphate, regulates inositol synthesis in mammalian cells. Ip6k1 ablation led to profound changes in DNA methylation and expression of Isyna1 (designated mIno1), which encodes the rate-limiting enzyme inositol-3-phosphate synthase. Interestingly, IP6K1 preferentially bound to the phospholipid phosphatidic acid, and this binding was required for IP6K1 nuclear localization and the regulation of mIno1 transcription. This is the first demonstration of IP6K1 as a novel negative regulator of inositol synthesis in mammalian cells.
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Affiliation(s)
- Wenxi Yu
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Cunqi Ye
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
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