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Rameh LE, York JD, Blind RD. Multiple inositol phosphate species enhance stability of active mTOR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.01.592113. [PMID: 38746235 PMCID: PMC11092565 DOI: 10.1101/2024.05.01.592113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Mechanistic Target of Rapamycin (mTOR) binds the small metabolite inositol hexakisphosphate (IP6) as shown in structures of mTOR, however it remains unclear if IP6, or any other inositol phosphate species, can activate mTOR kinase activity. Here, we show that multiple, exogenously added inositol phosphate species (IP6, IP5, IP4 and IP3) can all enhance the ability of mTOR and mTORC1 to auto-phosphorylate and incorporate radiolabeled phosphate into peptide substrates in in vitro kinase reactions. Although IP6 did not affect the apparent KM of mTORC1 for ATP, monitoring kinase activity over longer reaction times showed increased product formation, suggesting inositol phosphates stabilize an active form of mTORC1 in vitro. The effects of IP6 on mTOR were reversible, suggesting IP6 bound to mTOR can be exchanged dynamically with the free solvent. Interestingly, we also observed that IP6 could alter mTOR solubility and electrophoretic mobility in SDS-PAGE in the presence of manganese, suggesting divalent cations may play a role in inositol phosphate regulation of mTOR. Together, these data suggest for the first time that multiple inositol phosphate species (IP4, IP5 and IP6) can dynamically regulate mTOR and mTORC1 by promoting a stable, active state of the kinase. Our data suggest that studies of the dynamics of inositol phosphate regulation of mTOR are well justified.
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Affiliation(s)
- Lucia E. Rameh
- University of South Alabama, Department of Biochemistry and Molecular Biology, Mobile, AL 36688
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
- Vanderbilt University Medical Center, Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Nashville, TN 37232
| | - John D. York
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
| | - Raymond D. Blind
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232
- Vanderbilt University Medical Center, Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Nashville, TN 37232
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2
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Khan A, Mallick M, Ladke JS, Bhandari R. The ring rules the chain - inositol pyrophosphates and the regulation of inorganic polyphosphate. Biochem Soc Trans 2024; 52:567-580. [PMID: 38629621 DOI: 10.1042/bst20230256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/29/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024]
Abstract
The maintenance of phosphate homeostasis serves as a foundation for energy metabolism and signal transduction processes in all living organisms. Inositol pyrophosphates (PP-InsPs), composed of an inositol ring decorated with monophosphate and diphosphate moieties, and inorganic polyphosphate (polyP), chains of orthophosphate residues linked by phosphoanhydride bonds, are energy-rich biomolecules that play critical roles in phosphate homeostasis. There is a complex interplay between these two phosphate-rich molecules, and they share an interdependent relationship with cellular adenosine triphosphate (ATP) and inorganic phosphate (Pi). In eukaryotes, the enzymes involved in PP-InsP synthesis show some degree of conservation across species, whereas distinct enzymology exists for polyP synthesis among different organisms. In fact, the mechanism of polyP synthesis in metazoans, including mammals, is still unclear. Early studies on PP-InsP and polyP synthesis were conducted in the slime mould Dictyostelium discoideum, but it is in the budding yeast Saccharomyces cerevisiae that a clear understanding of the interplay between polyP, PP-InsPs, and Pi homeostasis has now been established. Recent research has shed more light on the influence of PP-InsPs on polyP in mammals, and the regulation of both these molecules by cellular ATP and Pi levels. In this review we will discuss the cross-talk between PP-InsPs, polyP, ATP, and Pi in the context of budding yeast, slime mould, and mammals. We will also highlight the similarities and differences in the relationship between these phosphate-rich biomolecules among this group of organisms.
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Affiliation(s)
- Azmi Khan
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500039, India
| | - Manisha Mallick
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500039, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Jayashree S Ladke
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500039, India
- Graduate Studies, Regional Centre for Biotechnology, Faridabad 121001, Haryana, India
| | - Rashna Bhandari
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500039, India
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3
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Márquez-Moñino MÁ, Ortega-García R, Whitfield H, Riley AM, Infantes L, Garrett SW, Shipton ML, Brearley CA, Potter BVL, González B. Substrate promiscuity of inositol 1,4,5-trisphosphate kinase driven by structurally-modified ligands and active site plasticity. Nat Commun 2024; 15:1502. [PMID: 38374076 PMCID: PMC10876669 DOI: 10.1038/s41467-024-45917-5] [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: 08/19/2023] [Accepted: 02/05/2024] [Indexed: 02/21/2024] Open
Abstract
D-myo-inositol 1,4,5-trisphosphate (InsP3) is a fundamental second messenger in cellular Ca2+ mobilization. InsP3 3-kinase, a highly specific enzyme binding InsP3 in just one mode, phosphorylates InsP3 specifically at its secondary 3-hydroxyl group to generate a tetrakisphosphate. Using a chemical biology approach with both synthetised and established ligands, combining synthesis, crystallography, computational docking, HPLC and fluorescence polarization binding assays using fluorescently-tagged InsP3, we have surveyed the limits of InsP3 3-kinase ligand specificity and uncovered surprisingly unforeseen biosynthetic capacity. Structurally-modified ligands exploit active site plasticity generating a helix-tilt. These facilitated uncovering of unexpected substrates phosphorylated at a surrogate extended primary hydroxyl at the inositol pseudo 3-position, applicable even to carbohydrate-based substrates. Crystallization experiments designed to allow reactions to proceed in situ facilitated unequivocal characterization of the atypical tetrakisphosphate products. In summary, we define features of InsP3 3-kinase plasticity and substrate tolerance that may be more widely exploitable.
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Affiliation(s)
- María Ángeles Márquez-Moñino
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry Blas Cabrera, CSIC, Serrano 119, 28006, Madrid, Spain
| | - Raquel Ortega-García
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry Blas Cabrera, CSIC, Serrano 119, 28006, Madrid, Spain
| | - Hayley Whitfield
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Andrew M Riley
- Drug Discovery and Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Lourdes Infantes
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry Blas Cabrera, CSIC, Serrano 119, 28006, Madrid, Spain
| | - Shane W Garrett
- Wolfson Laboratory of Medicinal Chemistry, Department of Life Sciences, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Megan L Shipton
- Drug Discovery and Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Charles A Brearley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Barry V L Potter
- Drug Discovery and Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
- Wolfson Laboratory of Medicinal Chemistry, Department of Life Sciences, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Beatriz González
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry Blas Cabrera, CSIC, Serrano 119, 28006, Madrid, Spain.
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4
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Song Z, Han H, Ge X, Das S, Desert R, Athavale D, Chen W, Komakula SSB, Lantvit D, Nieto N. Deficiency of neutrophil high-mobility group box-1 in liver transplant recipients exacerbates early allograft injury in mice. Hepatology 2023; 78:771-786. [PMID: 37016762 DOI: 10.1097/hep.0000000000000346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 02/10/2023] [Indexed: 04/06/2023]
Abstract
BACKGROUND AND AIMS Early allograft dysfunction (EAD) is a severe event leading to graft failure after liver transplant (LT). Extracellular high-mobility group box-1 (HMGB1) is a damage-associated molecular pattern that contributes to hepatic ischemia-reperfusion injury (IRI). However, the contribution of intracellular HMGB1 to LT graft injury remains elusive. We hypothesized that intracellular neutrophil-derived HMGB1 from recipients protects from post-LT EAD. APPROACH AND RESULTS We generated mice with conditional ablation or overexpression of Hmgb1 in hepatocytes, myeloid cells, or both. We performed LTs and injected lipopolysaccharide (LPS) to evaluate the effect of intracellular HMGB1 in EAD. Ablation of Hmgb1 in hepatocytes and myeloid cells of donors and recipients exacerbated early allograft injury after LT. Ablation of Hmgb1 from liver grafts did not affect graft injury; however, lack of Hmgb1 from recipient myeloid cells increased reactive oxygen species (ROS) and inflammation in liver grafts and exacerbated injury. Neutrophils lacking HMGB1 were more activated, showed enhanced pro-oxidant and pro-inflammatory signatures, and reduced biosynthesis and metabolism of inositol polyphosphates (InsPs). On LT reperfusion or LPS treatment, there was significant neutrophil mobilization and infiltration into the liver and enhanced production of ROS and pro-inflammatory cytokines when intracellular Hmgb1 was absent. Depletion of neutrophils using anti-Ly6G antibody attenuated graft injury in recipients with myeloid cell Hmgb1 ablation. CONCLUSIONS Neutrophil HMGB1 derived from recipients is central to regulate their activation, limits the production of ROS and pro-inflammatory cytokines, and protects from early liver allograft injury.
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Affiliation(s)
- Zhuolun Song
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Hui Han
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Xiaodong Ge
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Sukanta Das
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Romain Desert
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Dipti Athavale
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Wei Chen
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | | | - Daniel Lantvit
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Natalia Nieto
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
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5
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Pires SMG, Reis RS, Cardoso SM, Pezzani R, Paredes-Osses E, Seilkhan A, Ydyrys A, Martorell M, Sönmez Gürer E, Setzer WN, Abdull Razis AF, Modu B, Calina D, Sharifi-Rad J. Phytates as a natural source for health promotion: A critical evaluation of clinical trials. Front Chem 2023; 11:1174109. [PMID: 37123871 PMCID: PMC10140425 DOI: 10.3389/fchem.2023.1174109] [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: 02/25/2023] [Accepted: 04/03/2023] [Indexed: 05/02/2023] Open
Abstract
Phytates are a type of organophosphorus compound produced in terrestrial ecosystems by plants. In plant feeds, phytic acid and its salt form, phytate, account for 60%-80% of total phosphorus. Because phytate is a polyanionic molecule, it can chelate positively charged cations such as calcium, iron, and zinc. Due to its prevalence in vegetal tissues and the fact that people consume plants, phytate was first considered a potential health benefit. This updated review aims to summarize the current data on the results of clinical trials of phytates on human health, highlighting both beneficial and undesirable effects. To obtain these updated data, published papers in electronic databases such as PubMed/MedLine, TRIP database, Wiley, Google Scholar, Baidu, and Scopus were searched. Study results have shown that phytate can have beneficial health effects such as antioxidant, anticancer potential and reduction of pathological calcifications in blood vessels and organs; but also, negative effects by reducing the absorption of minerals important for maintaining the homeostasis of the human body. According to these recent results derived from recent clinical studies, phytates may be a potential natural source for health benefits. To improve clinical efficacy and human health benefits, further dose-response studies are needed to determine effective therapeutic doses and potential interactions with conventional drugs.
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Affiliation(s)
- Sónia M. G. Pires
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Rita Silva Reis
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Susana M. Cardoso
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal
- *Correspondence: Susana M. Cardoso, ; Miquel Martorell, ; Ahmad Faizal Abdull Razis, ; Daniela Calina, ; Javad Sharifi-Rad,
| | - Raffaele Pezzani
- Phytotherapy Lab (PhT-Lab), Endocrinology Unit, Department of Medicine (DIMED), University of Padova, Padova, Italy
- AIROB, Associazione Italiana per la Ricerca Oncologica di Base, Padova, Italy
| | - Esteban Paredes-Osses
- Instituto de Ciencias Naturales, Facultad de Medicina Veterinaria y Agronomía, Universidad de Las Américas, Las Américas, Chile
| | - Ainur Seilkhan
- Educational Program, Geography, Environment and Service Sector, Abai Kazakh National Pedagogical University, Almaty, Kazakhstan
| | - Alibek Ydyrys
- Biomedical Research Centre, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Miquel Martorell
- Centre for Healthy Living, Department of Nutrition and Dietetics, Faculty of Pharmacy, University of Concepción, Concepción, Chile
- Unidad de Desarrollo Tecnológico, UDT, Universidad de Concepción, Concepción, Chile
- *Correspondence: Susana M. Cardoso, ; Miquel Martorell, ; Ahmad Faizal Abdull Razis, ; Daniela Calina, ; Javad Sharifi-Rad,
| | - Eda Sönmez Gürer
- Department of Pharmacognosy, Faculty of Pharmacy, Sivas Cumhuriyet University, Sivas, Türkiye
| | - William N. Setzer
- Aromatic Plant Research Center, Lehi, UT, United States
- Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL, United States
| | - Ahmad Faizal Abdull Razis
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Natural Medicines and Products Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- *Correspondence: Susana M. Cardoso, ; Miquel Martorell, ; Ahmad Faizal Abdull Razis, ; Daniela Calina, ; Javad Sharifi-Rad,
| | - Babagana Modu
- Natural Medicines and Products Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Department of Biochemistry, Faculty of Science, University of Maiduguri, Maiduguri, Borno, Nigeria
| | - Daniela Calina
- Department of Clinical Pharmacy, University of Medicine and Pharmacy of Craiova, Craiova, Romania
- *Correspondence: Susana M. Cardoso, ; Miquel Martorell, ; Ahmad Faizal Abdull Razis, ; Daniela Calina, ; Javad Sharifi-Rad,
| | - Javad Sharifi-Rad
- Facultad de Medicina, Universidad del Azuay, Cuenca, Ecuador
- *Correspondence: Susana M. Cardoso, ; Miquel Martorell, ; Ahmad Faizal Abdull Razis, ; Daniela Calina, ; Javad Sharifi-Rad,
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6
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Ahmed N, Kidane B, Wang L, Nugent Z, Moldovan N, McElrea A, Shariati-Ievari S, Qing G, Tan L, Buduhan G, Srinathan SK, Meyers R, Aliani M. Metabolic Alterations in Sputum and Exhaled Breath Condensate of Early Stage Non-Small Cell Lung Cancer Patients After Surgical Resection: A Pilot Study. Front Oncol 2022; 12:874964. [PMID: 35719971 PMCID: PMC9204221 DOI: 10.3389/fonc.2022.874964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 04/27/2022] [Indexed: 12/19/2022] Open
Abstract
Every year, close to two million people world-wide are diagnosed with and die of lung cancer. Most patients present with advanced-stage cancer with limited curative options and poor prognosis. Diagnosis of lung cancer at an early stage provides the best chance for a cure. Low- dose CT screening of the chest in the high-risk population is the current standard of care for early detection of lung cancer. However, CT screening is invasive due to radiation exposure and carries the risk of unnecessary biopsies in non-cancerous tumors. In this pilot study, we present metabolic alterations observed in sputum and breath condensate of the same population of early- stage non-small cell lung cancer (NSCLC) patients cancer before and after surgical resection (SR), which could serve as noninvasive diagnostic tool. Exhaled breath condensate (EBC) (n=35) and sputum (n=15) were collected from early-stage non-small cell lung cancer (NSCLC) patients before and after SR. Median number of days for EBC and sputum collection before and after SR were 7 and 42; and 7 and 36 respectively Nuclear magnetic resonance (NMR) and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) were used to analyze the metabolic profile of the collected samples. A total of 26 metabolites with significant alteration post SR were identified, of which 14 (54%) were lipids and 12 constituted nine different chemical metabolite classes. Eighteen metabolites (69%) were significantly upregulated and 8 (31%) were downregulated. Median fold change for all the up- and downregulated metabolites (LC-QTOF-MS) were 10 and 8, respectively. Median fold change (MFC) in concentration of all the up- and downregulated metabolites (NMR) were 0.04 and 0.27, respectively. Furthermore, glucose (median fold change, 0.01, p=0.037), adenosine monophosphate (13 log fold, p=0.0037) and N1, N12- diacetylspermine (8 log fold p=0.011) sputum levels were significantly increased post-SR. These identified sputa and EBC indices of altered metabolism could serve as basis for further exploration of biomarkers for early detection of lung cancer, treatment response, and targets for drug discovery. Validation of these promising results by larger clinical studies is warranted.
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Affiliation(s)
- Naseer Ahmed
- CancerCare Manitoba Research Institute, Winnipeg, MB, Canada
- Department of Radiology, Section of Radiation Oncology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Biniam Kidane
- CancerCare Manitoba Research Institute, Winnipeg, MB, Canada
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Le Wang
- Department of Epidemiology and Cancer Registry, CancerCare Manitoba, Winnipeg, MB, Canada
- St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - Zoann Nugent
- Department of Epidemiology and Cancer Registry, CancerCare Manitoba, Winnipeg, MB, Canada
| | - Nataliya Moldovan
- Department of Radiology, Section of Radiation Oncology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - April McElrea
- St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | | | - Gefei Qing
- Department of Pathology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Lawrence Tan
- Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Gordon Buduhan
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Sadeesh K. Srinathan
- Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Renelle Meyers
- BC Cancer Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Michel Aliani
- St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada
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7
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Ricaña CL, Dick RA. Inositol Phosphates and Retroviral Assembly: A Cellular Perspective. Viruses 2021; 13:v13122516. [PMID: 34960784 PMCID: PMC8703376 DOI: 10.3390/v13122516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 12/13/2022] Open
Abstract
Understanding the molecular mechanisms of retroviral assembly has been a decades-long endeavor. With the recent discovery of inositol hexakisphosphate (IP6) acting as an assembly co-factor for human immunodeficiency virus (HIV), great strides have been made in retroviral research. In this review, the enzymatic pathways to synthesize and metabolize inositol phosphates (IPs) relevant to retroviral assembly are discussed. The functions of these enzymes and IPs are outlined in the context of the cellular biology important for retroviruses. Lastly, the recent advances in understanding the role of IPs in retroviral biology are surveyed.
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8
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Vucenik I. Bioactivity of Inositol Phosphates. Molecules 2021; 26:molecules26165042. [PMID: 34443630 PMCID: PMC8400110 DOI: 10.3390/molecules26165042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 11/16/2022] Open
Affiliation(s)
- Ivana Vucenik
- Department of Medical and Research Technology, University of Maryland School of Medicine, 100 Penn Street, Baltimore, MD 21201, USA; ; Tel.: +1-(410)-706-1832; Fax: +1-(410)-706-5229
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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9
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Innate immunity to prions: anti-prion systems turn a tsunami of prions into a slow drip. Curr Genet 2021; 67:833-847. [PMID: 34319422 DOI: 10.1007/s00294-021-01203-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 12/17/2022]
Abstract
The yeast prions (infectious proteins) [URE3] and [PSI+] are essentially non-functional (or even toxic) amyloid forms of Ure2p and Sup35p, whose normal function is in nitrogen catabolite repression and translation termination, respectively. Yeast has an array of systems working in normal cells that largely block infection with prions, block most prion formation, cure most nascent prions and mitigate the toxic effects of those prions that escape the first three types of systems. Here we review recent progress in defining these anti-prion systems, how they work and how they are regulated. Polymorphisms of the prion domains partially block infection with prions. Ribosome-associated chaperones ensure proper folding of nascent proteins, thus reducing [PSI+] prion formation and curing many [PSI+] variants that do form. Btn2p is a sequestering protein which gathers [URE3] amyloid filaments to one place in the cells so that the prion is often lost by progeny cells. Proteasome impairment produces massive overexpression of Btn2p and paralog Cur1p, resulting in [URE3] curing. Inversely, increased proteasome activity, by derepression of proteasome component gene transcription or by 60S ribosomal subunit gene mutation, prevents prion curing by Btn2p or Cur1p. The nonsense-mediated decay proteins (Upf1,2,3) cure many nascent [PSI+] variants by associating with Sup35p directly. Normal levels of the disaggregating chaperone Hsp104 can also cure many [PSI+] prion variants. By keeping the cellular levels of certain inositol polyphosphates / pyrophosphates low, Siw14p cures certain [PSI+] variants. It is hoped that exploration of the yeast innate immunity to prions will lead to discovery of similar systems in humans.
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10
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Bizzarri M, Logoteta P, Monastra G, Laganà AS. An innovative approach to polycystic ovary syndrome. J OBSTET GYNAECOL 2021; 42:546-556. [PMID: 34169781 DOI: 10.1080/01443615.2021.1920006] [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] [Indexed: 10/21/2022]
Abstract
Myo-inositol and D-chiro-inositol are insulin sensitising agents. In the ovary, myo-inositol acts as second messenger of Follicle Stimulating Hormone (FSH). Both molecules were administered to Polycystic Ovary Syndrome (PCOS) women. The gynaecologist Vittorio Unfer was the first to give specific value to myo-inositol for the treatment of PCOS: this important innovation opened new ways of research to identify efficient therapies based on myo-inositol alone or with low doses of D-chiro-inositol. Significant successes were also gained using myo-inositol in treating male and female infertility. Unfer's researches allowed to identify "the D-Chiro-Inositol Paradox in the Ovary" and the best myo-inositol/D-chiro-inositol ratio (40:1) for the treatment of PCOS. Furthermore, his studies allowed to improve the inositol's efficacy using alpha-lactalbumin. As shown in this review, the main stages of Unfer's scientific career have been closely intertwined with important phases of the recent pharmacological research about the topic.
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Affiliation(s)
- Mariano Bizzarri
- Department of Experimental Medicine, Systems Biology Group Lab, Sapienza University of Rome, Rome, Italy
| | | | | | - Antonio Simone Laganà
- Department of Obstetrics and Gynecology, "Filippo Del Ponte" Hospital, University of Insubria, Varese, Italy
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11
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Analytical Methods for Determination of Phytic Acid and Other Inositol Phosphates: A Review. Molecules 2020; 26:molecules26010174. [PMID: 33396544 PMCID: PMC7795710 DOI: 10.3390/molecules26010174] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/28/2020] [Accepted: 12/29/2020] [Indexed: 12/12/2022] Open
Abstract
From the early precipitation-based techniques, introduced more than a century ago, to the latest development of enzymatic bio- and nano-sensor applications, the analysis of phytic acid and/or other inositol phosphates has never been a straightforward analytical task. Due to the biomedical importance, such as antinutritional, antioxidant and anticancer effects, several types of methodologies were investigated over the years to develop a reliable determination of these intriguing analytes in many types of biological samples; from various foodstuffs to living cell organisms. The main aim of the present work was to critically overview the development of the most relevant analytical principles, separation and detection methods that have been applied in order to overcome the difficulties with specific chemical properties of inositol phosphates, their interferences, absence of characteristic signal (e.g., absorbance), and strong binding interactions with (multivalent) metals and other biological molecules present in the sample matrix. A systematical and chronological review of the applied methodology and the detection system is given, ranging from the very beginnings of the classical gravimetric and titrimetric analysis, through the potentiometric titrations, chromatographic and electrophoretic separation techniques, to the use of spectroscopic methods and of the recently reported fluorescence and voltammetric bio- and nano-sensors.
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