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Dinicola S, Minini M, Unfer V, Verna R, Cucina A, Bizzarri M. Nutritional and Acquired Deficiencies in Inositol Bioavailability. Correlations with Metabolic Disorders. Int J Mol Sci 2017; 18:E2187. [PMID: 29053604 PMCID: PMC5666868 DOI: 10.3390/ijms18102187] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/09/2017] [Accepted: 10/17/2017] [Indexed: 01/02/2023] Open
Abstract
Communities eating a western-like diet, rich in fat, sugar and significantly deprived of fibers, share a relevant increased risk of both metabolic and cancerous diseases. Even more remarkable is that a low-fiber diet lacks some key components-as phytates and inositols-for which a mechanistic link has been clearly established in the pathogenesis of both cancer and metabolic illness. Reduced bioavailability of inositol in living organisms could arise from reduced food supply or from metabolism deregulation. Inositol deregulation has been found in a number of conditions mechanistically and epidemiologically associated to high-glucose diets or altered glucose metabolism. Indeed, high glucose levels hinder inositol availability by increasing its degradation and by inhibiting both myo-Ins biosynthesis and absorption. These underappreciated mechanisms may likely account for acquired, metabolic deficiency in inositol bioavailability.
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Affiliation(s)
- Simona Dinicola
- Department of Experimental Medicine, Systems Biology Group, Sapienza University of Rome, viale Regina Elena 324, 00161 Rome, Italy.
- Department of Surgery "Pietro Valdoni", Sapienza University of Rome, Via Antonio Scarpa 14, 00161 Rome, Italy.
| | - Mirko Minini
- Department of Experimental Medicine, Systems Biology Group, Sapienza University of Rome, viale Regina Elena 324, 00161 Rome, Italy.
- Department of Surgery "Pietro Valdoni", Sapienza University of Rome, Via Antonio Scarpa 14, 00161 Rome, Italy.
| | - Vittorio Unfer
- Department of Medical Sciences, IPUS-Institute of Higher Education, 5250 Chiasso, Switzerland.
| | - Roberto Verna
- Department of Experimental Medicine, Systems Biology Group, Sapienza University of Rome, viale Regina Elena 324, 00161 Rome, Italy.
| | - Alessandra Cucina
- Department of Surgery "Pietro Valdoni", Sapienza University of Rome, Via Antonio Scarpa 14, 00161 Rome, Italy.
- Policlinico Umberto I, viale del Policlinico 155, 00161 Rome, Italy.
| | - Mariano Bizzarri
- Department of Experimental Medicine, Systems Biology Group, Sapienza University of Rome, viale Regina Elena 324, 00161 Rome, Italy.
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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: 103] [Impact Index Per Article: 12.9] [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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Bizzarri M, Dinicola S, Bevilacqua A, Cucina A. Broad Spectrum Anticancer Activity of Myo-Inositol and Inositol Hexakisphosphate. Int J Endocrinol 2016; 2016:5616807. [PMID: 27795708 PMCID: PMC5067332 DOI: 10.1155/2016/5616807] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/06/2016] [Indexed: 02/06/2023] Open
Abstract
Inositols (myo-inositol and inositol hexakisphosphate) exert a wide range of critical activities in both physiological and pathological settings. Deregulated inositol metabolism has been recorded in a number of diseases, including cancer, where inositol modulates different critical pathways. Inositols inhibit pRB phosphorylation, fostering the pRB/E2F complexes formation and blocking progression along the cell cycle. Inositols reduce PI3K levels, thus counteracting the activation of the PKC/RAS/ERK pathway downstream of PI3K activation. Upstream of that pathway, inositols disrupt the ligand interaction between FGF and its receptor as well as with the EGF-transduction processes involving IGF-II receptor and AP-1 complexes. Additionally, Akt activation is severely impaired upon inositol addition. Downregulation of both Akt and ERK leads consequently to NF-kB inhibition and reduced expression of inflammatory markers (COX-2 and PGE2). Remarkably, inositol-induced downregulation of presenilin-1 interferes with the epithelial-mesenchymal transition and reduces Wnt-activation, β-catenin translocation, Notch-1, N-cadherin, and SNAI1 release. Inositols interfere also with the cytoskeleton by upregulating Focal Adhesion Kinase and E-cadherin and decreasing Fascin and Cofilin, two main components of pseudopodia, leading hence to invasiveness impairment. This effect is reinforced by the inositol-induced inhibition on metalloproteinases and ROCK1/2 release. Overall, these effects enable inositols to remodel the cytoskeleton architecture.
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Affiliation(s)
- Mariano Bizzarri
- Department of Experimental Medicine, Sapienza University of Rome, Viale Regina Elena 324, 00161 Rome, Italy
- Systems Biology Group Lab, Sapienza University of Rome, Rome, Italy
- *Mariano Bizzarri:
| | - Simona Dinicola
- Department of Clinical and Molecular Medicine, Sapienza University of Rome, Viale Regina Elena 336, 00161 Rome, Italy
- Department of Surgery “Pietro Valdoni”, Sapienza University of Rome, Via A. Scarpa 14, 00161 Rome, Italy
| | - Arturo Bevilacqua
- Department of Psychology, Section of Neuroscience, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy
| | - Alessandra Cucina
- Department of Surgery “Pietro Valdoni”, Sapienza University of Rome, Via A. Scarpa 14, 00161 Rome, Italy
- Azienda Policlinico Umberto I, Viale del Policlinico 155, 00161 Rome, Italy
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Wilson MSC, Bulley SJ, Pisani F, Irvine RF, Saiardi A. A novel method for the purification of inositol phosphates from biological samples reveals that no phytate is present in human plasma or urine. Open Biol 2015; 5:150014. [PMID: 25808508 PMCID: PMC4389793 DOI: 10.1098/rsob.150014] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Inositol phosphates are a large and diverse family of signalling molecules. While
genetic studies have discovered important functions for them, the biochemistry
behind these roles is often not fully characterized. A key obstacle in inositol
phosphate research in mammalian cells has been the lack of straightforward
techniques for their purification and analysis. Here we describe the ability of
titanium dioxide (TiO2) beads to bind inositol phosphates. This
discovery allowed the development of a new purification protocol that, coupled
with gel analysis, permitted easy identification and quantification of
InsP6 (phytate), its pyrophosphate derivatives InsP7
and InsP8, and the nucleotides ATP and GTP from cell or tissue
extracts. Using this approach, InsP6, InsP7 and
InsP8 were visualized in Dictyostelium extracts
and a variety of mammalian cell lines and tissues, and the effects of metabolic
perturbation on these were explored. TiO2 bead purification also
enabled us to quantify InsP6 in human plasma and urine, which led to
two distinct but related observations. Firstly, there is an active
InsP6 phosphatase in human plasma, and secondly, InsP6
is undetectable in either fluid. These observations seriously question reports
that InsP6 is present in human biofluids and the advisability of
using InsP6 as a dietary supplement.
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Affiliation(s)
- Miranda S C Wilson
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Simon J Bulley
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK Department of Haematology, Cambridge University Hospitals NHS Trust, Hills Road, Cambridge CB2 0QQ, UK
| | - Francesca Pisani
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK Department of Biology, Ecology and Earth Science, University of Calabria, Rende, Italy
| | - Robin F Irvine
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
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Inositol 1,3,4,5,6-pentakisphosphate 2-kinase is a distant IPK member with a singular inositide binding site for axial 2-OH recognition. Proc Natl Acad Sci U S A 2010; 107:9608-13. [PMID: 20453199 DOI: 10.1073/pnas.0912979107] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Inositol phosphates (InsPs) are signaling molecules with multiple roles in cells. In particular (InsP(6)) is involved in mRNA export and editing or chromatin remodeling among other events. InsP(6) accumulates as mixed salts (phytate) in storage tissues of plants and plays a key role in their physiology. Human diets that are exclusively grain-based provide an excess of InsP(6) that, through chelation of metal ions, may have a detrimental effect on human health. Ins(1,3,4,5,6)P(5) 2-kinase (InsP(5) 2-kinase or Ipk1) catalyses the synthesis of InsP(6) from InsP(5) and ATP, and is the only enzyme that transfers a phosphate group to the axial 2-OH of the myo-inositide. We present the first structure for an InsP(5) 2-kinase in complex with both substrates and products. This enzyme presents a singular structural region for inositide binding that encompasses almost half of the protein. The key residues in substrate binding are identified, with Asp368 being responsible for recognition of the axial 2-OH. This study sheds light on the unique molecular mechanism for the synthesis of the precursor of inositol pyrophosphates.
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Abstract
A highly specific and sensitive mass assay for inositol hexakisphosphate (InsP6) was characterized. This centres around phosphorylating InsP6 with [32P]ATP using a recombinant InsP6 kinase from Giardia lambia, followed by HPLC of the 32P-labelled products with an internal [3H]InsP7 standard. This assay was used to quantify InsP6 levels in a variety of biological samples. Concentrations of InsP6 in rat tissues varied from 10–20 μM (assuming 64% of wet weight of tissue is cytosol water), whereas using the same assumption axenic Dictyostelium discoideum cells contained 352±11 μM InsP6. HeLa cells were seeded at low density and grown to confluence, at which point they contained InsP6 levels per mg of protein similar to rat tissues. This amounted to 1.952±0.117 nmol InsP6 per culture dish, despite the cells being grown in serum shown to contain no detectable (less than 20 pmol per dish) InsP6. These results demonstrate that mammalian cells synthesize all their own InsP6. Human blood was analysed, and although the white cell fraction contained InsP6 at a concentration comparable with other tissues, in serum and platelet-free plasma no InsP6 was detected (<1 nM InsP6). Human urine was also examined, and also contained no detectable (<5 nM) InsP6. These results suggest that dietary studies purporting to measure InsP6 at micromolar concentrations in human plasma or urine may not have been quantifying this inositol phosphate. Therefore claims that administrating InsP6 in the diet or applying it topically can produce health benefits by increasing extracellular InsP6 levels may require reassessment.
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