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Soueid DM, Garner AL. Adaptation of RiPCA for the Live-Cell Detection of mRNA-Protein Interactions. Biochemistry 2023; 62:3323-3336. [PMID: 37963240 DOI: 10.1021/acs.biochem.3c00334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
RNA-binding proteins (RBPs) act as essential regulators of cell fate decisions, through their ability to bind and regulate the activity of cellular RNAs. For protein-coding mRNAs, RBPs control the localization, stability, degradation, and ultimately translation of mRNAs to impact gene expression. Disruption of the vast network of mRNA-protein interactions has been implicated in many human diseases, and accordingly, targeting these interactions has surfaced as a new frontier in RNA-targeted drug discovery. To catalyze this new field, methods are needed to enable the detection and subsequent screening of mRNA-RBP interactions, particularly in live cells. Using our laboratory's RNA-interaction with Protein-mediated Complementation Assay (RiPCA) technology, herein we describe its application to mRNA-protein interactions and present a guide for the development of future RiPCA assays for structurally diverse classes of mRNA-protein interactions.
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Affiliation(s)
- Dalia M Soueid
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
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2
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Salvato I, Ricciardi L, Dal Col J, Nigro A, Giurato G, Memoli D, Sellitto A, Lamparelli EP, Crescenzi MA, Vitale M, Vatrella A, Nucera F, Brun P, Caicci F, Dama P, Stiff T, Castellano L, Idrees S, Johansen MD, Faiz A, Wark PA, Hansbro PM, Adcock IM, Caramori G, Stellato C. Expression of targets of the RNA-binding protein AUF-1 in human airway epithelium indicates its role in cellular senescence and inflammation. Front Immunol 2023; 14:1192028. [PMID: 37483631 PMCID: PMC10360199 DOI: 10.3389/fimmu.2023.1192028] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 06/06/2023] [Indexed: 07/25/2023] Open
Abstract
Introduction The RNA-binding protein AU-rich-element factor-1 (AUF-1) participates to posttranscriptional regulation of genes involved in inflammation and cellular senescence, two pathogenic mechanisms of chronic obstructive pulmonary disease (COPD). Decreased AUF-1 expression was described in bronchiolar epithelium of COPD patients versus controls and in vitro cytokine- and cigarette smoke-challenged human airway epithelial cells, prompting the identification of epithelial AUF-1-targeted transcripts and function, and investigation on the mechanism of its loss. Results RNA immunoprecipitation-sequencing (RIP-Seq) identified, in the human airway epithelial cell line BEAS-2B, 494 AUF-1-bound mRNAs enriched in their 3'-untranslated regions for a Guanine-Cytosine (GC)-rich binding motif. AUF-1 association with selected transcripts and with a synthetic GC-rich motif were validated by biotin pulldown. AUF-1-targets' steady-state levels were equally affected by partial or near-total AUF-1 loss induced by cytomix (TNFα/IL1β/IFNγ/10 nM each) and siRNA, respectively, with differential transcript decay rates. Cytomix-mediated decrease in AUF-1 levels in BEAS-2B and primary human small-airways epithelium (HSAEC) was replicated by treatment with the senescence- inducer compound etoposide and associated with readouts of cell-cycle arrest, increase in lysosomal damage and senescence-associated secretory phenotype (SASP) factors, and with AUF-1 transfer in extracellular vesicles, detected by transmission electron microscopy and immunoblotting. Extensive in-silico and genome ontology analysis found, consistent with AUF-1 functions, enriched RIP-Seq-derived AUF-1-targets in COPD-related pathways involved in inflammation, senescence, gene regulation and also in the public SASP proteome atlas; AUF-1 target signature was also significantly represented in multiple transcriptomic COPD databases generated from primary HSAEC, from lung tissue and from single-cell RNA-sequencing, displaying a predominant downregulation of expression. Discussion Loss of intracellular AUF-1 may alter posttranscriptional regulation of targets particularly relevant for protection of genomic integrity and gene regulation, thus concurring to airway epithelial inflammatory responses related to oxidative stress and accelerated aging. Exosomal-associated AUF-1 may in turn preserve bound RNA targets and sustain their function, participating to spreading of inflammation and senescence to neighbouring cells.
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Affiliation(s)
- Ilaria Salvato
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
- Respiratory Medicine Unit, Department of Biomedical Sciences, Dentistry and Morphological and Functional Imaging (BIOMORF), University of Messina, Messina, Italy
| | - Luca Ricciardi
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
- Respiratory Medicine Unit, Department of Biomedical Sciences, Dentistry and Morphological and Functional Imaging (BIOMORF), University of Messina, Messina, Italy
| | - Jessica Dal Col
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Annunziata Nigro
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Giorgio Giurato
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Domenico Memoli
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Assunta Sellitto
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Erwin Pavel Lamparelli
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Maria Assunta Crescenzi
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Monica Vitale
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Alessandro Vatrella
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
| | - Francesco Nucera
- Respiratory Medicine Unit, Department of Biomedical Sciences, Dentistry and Morphological and Functional Imaging (BIOMORF), University of Messina, Messina, Italy
| | - Paola Brun
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | | | - Paola Dama
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Thomas Stiff
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Leandro Castellano
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Sobia Idrees
- Centre for Inflammation, Centenary Institute and University of Technology Sydney, Faculty of Science, School of Life Sciences, Sydney, NSW, Australia
| | - Matt D. Johansen
- Centre for Inflammation, Centenary Institute and University of Technology Sydney, Faculty of Science, School of Life Sciences, Sydney, NSW, Australia
| | - Alen Faiz
- Centre for Inflammation, Centenary Institute and University of Technology Sydney, Faculty of Science, School of Life Sciences, Sydney, NSW, Australia
| | - Peter A. Wark
- Immune Health, Hunter Medical Research Institute and The University of Newcastle, Newcastle, NSW, Australia
| | - Philip M. Hansbro
- Centre for Inflammation, Centenary Institute and University of Technology Sydney, Faculty of Science, School of Life Sciences, Sydney, NSW, Australia
- Immune Health, Hunter Medical Research Institute and The University of Newcastle, Newcastle, NSW, Australia
| | - Ian M. Adcock
- National Heart and Lung Institute, Imperial College London and the National Institute for Health and Care Research (NIHR) Imperial Biomedical Research Centre, London, United Kingdom
| | - Gaetano Caramori
- Respiratory Medicine Unit, Department of Biomedical Sciences, Dentistry and Morphological and Functional Imaging (BIOMORF), University of Messina, Messina, Italy
| | - Cristiana Stellato
- Department of Medicine, Surgery and Dentistry ‘Scuola Medica Salernitana’, University of Salerno, Salerno, Italy
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3
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Gargani S, Lourou N, Arapatzi C, Tzanos D, Saridaki M, Dushku E, Chatzimike M, Sidiropoulos ND, Andreadou M, Ntafis V, Hatzis P, Kostourou V, Kontoyiannis DL. Inactivation of AUF1 in Myeloid Cells Protects From Allergic Airway and Tumor Infiltration and Impairs the Adenosine-Induced Polarization of Pro-Angiogenic Macrophages. Front Immunol 2022; 13:752215. [PMID: 35222366 PMCID: PMC8873154 DOI: 10.3389/fimmu.2022.752215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 01/21/2022] [Indexed: 11/13/2022] Open
Abstract
The four isoforms of the RNA-binding protein hnRNPD/AUF1 have been proposed to limit the use of inflammatory mRNAs in innate immune cells. Mice engineered to lack AUF1s in all tissues are sensitive to acute inflammatory assaults; however, they also manifest complex degenerations obscuring assessment of AUF1s’ roles in innate immune cells. Here, we restricted a debilitating AUF1 mutation to the mouse myeloid lineage and performed disease-oriented phenotypic analyses to assess the requirement of AUF1s in variable contexts of innate immune reactivity. Contrary to the whole-body mutants, the myeloid mutants of AUF1s did not show differences in their susceptibility to cytokine storms occurring during endotoxemia; neither in type-I cell-mediated reactions driving intestinal inflammation by chemical irritants. Instead, they were resistant to allergic airway inflammation and displayed reductions in inflammatory infiltrates and an altered T-helper balance. The ex-vivo analysis of macrophages revealed that the loss of AUF1s had a minimal effect on their proinflammatory gene expression. Moreover, AUF1s were dispensable for the classical polarization of cultured macrophages by LPS & IFNγ correlating with the unchanged response of mutant mice to systemic and intestinal inflammation. Notably, AUF1s were also dispensable for the alternative polarization of macrophages by IL4, TGFβ and IL10, known to be engaged in allergic reactions. In contrast, they were required to switch proinflammatory macrophages towards a pro-angiogenic phenotype induced by adenosine receptor signals. Congruent to this, the myeloid mutants of AUF1 displayed lower levels of vascular remodeling factors in exudates from allergen exposed lungs; were unable to support the growth and inflammatory infiltration of transplanted melanoma tumors; and failed to vascularize inert grafts unless supplemented with angiogenic factors. Mechanistically, adenosine receptor signals enhanced the association of AUF1s with the Vegfa, Il12b, and Tnf mRNAs to differentially regulate and facilitate the pro-angiogenic switch. Our data collectively demonstrates that AUF1s do not act as general anti-inflammatory factors in innate immune cells but have more specialized roles in regulons allowing specific innate immune cell transitions to support tissue infiltration and remodeling processes.
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Affiliation(s)
- Sofia Gargani
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
- Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Niki Lourou
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
- Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Christina Arapatzi
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
| | - Dimitris Tzanos
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
| | - Marania Saridaki
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
| | - Esmeralda Dushku
- Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Margarita Chatzimike
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
| | - Nikolaos D. Sidiropoulos
- Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Margarita Andreadou
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
| | - Vasileios Ntafis
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
| | - Pantelis Hatzis
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
| | - Vassiliki Kostourou
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
| | - Dimitris L. Kontoyiannis
- Biomedical Sciences Research Centre “Alexander Fleming”, Institute of Fundamental Biomedical Research, Vari, Greece
- Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
- *Correspondence: Dimitris L. Kontoyiannis, ;
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4
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Solano-Gonzalez E, Coburn KM, Yu W, Wilson GM, Nurmemmedov E, Kesari S, Chang ET, MacKerell AD, Weber DJ, Carrier F. Small molecules inhibitors of the heterogeneous ribonuclear protein A18 (hnRNP A18): a regulator of protein translation and an immune checkpoint. Nucleic Acids Res 2021; 49:1235-1246. [PMID: 33398344 PMCID: PMC7897483 DOI: 10.1093/nar/gkaa1254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 12/01/2022] Open
Abstract
We have identified chemical probes that simultaneously inhibit cancer cell progression and an immune checkpoint. Using the computational Site Identification by Ligand Competitive Saturation (SILCS) technology, structural biology and cell-based assays, we identify small molecules that directly and selectively bind to the RNA Recognition Motif (RRM) of hnRNP A18, a regulator of protein translation in cancer cells. hnRNP A18 recognizes a specific RNA signature motif in the 3′UTR of transcripts associated with cancer cell progression (Trx, VEGF, RPA) and, as shown here, a tumor immune checkpoint (CTLA-4). Post-transcriptional regulation of immune checkpoints is a potential therapeutic strategy that remains to be exploited. The probes target hnRNP A18 RRM in vitro and in cells as evaluated by cellular target engagement. As single agents, the probes specifically disrupt hnRNP A18–RNA interactions, downregulate Trx and CTLA-4 protein levels and inhibit proliferation of several cancer cell lines without affecting the viability of normal epithelial cells. These first-in-class chemical probes will greatly facilitate the elucidation of the underexplored biological function of RNA Binding Proteins (RBPs) in cancer cells, including their effects on proliferation and immune checkpoint activation.
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Affiliation(s)
- Eduardo Solano-Gonzalez
- University of Maryland, Baltimore, School of Medicine, Department of Radiation Oncology, 655 West Baltimore, Street, Baltimore, MD 21201, USA
| | - Katherine M Coburn
- University of Maryland, Baltimore, School of Medicine, Department of Biochemistry and Molecular Biology, 108 N. Greene Street, Baltimore, MD 21201, USA
| | - Wenbo Yu
- Computer-Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, 20 Penn Street, Baltimore MD 21201, USA.,Center for Biomolecular Therapeutics (CBT), University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Gerald M Wilson
- University of Maryland, Baltimore, School of Medicine, Department of Biochemistry and Molecular Biology, 108 N. Greene Street, Baltimore, MD 21201, USA
| | - Elmar Nurmemmedov
- John Wayne Cancer Institute, 2200 Santa Monica Blvd, Santa Monica, CA 90404, USA
| | - Santosh Kesari
- John Wayne Cancer Institute, 2200 Santa Monica Blvd, Santa Monica, CA 90404, USA
| | - Elizabeth T Chang
- University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
| | - Alexander D MacKerell
- Computer-Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, 20 Penn Street, Baltimore MD 21201, USA.,Center for Biomolecular Therapeutics (CBT), University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - David J Weber
- University of Maryland, Baltimore, School of Medicine, Department of Biochemistry and Molecular Biology, 108 N. Greene Street, Baltimore, MD 21201, USA.,University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA.,Center for Biomolecular Therapeutics (CBT), University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - France Carrier
- University of Maryland, Baltimore, School of Medicine, Department of Radiation Oncology, 655 West Baltimore, Street, Baltimore, MD 21201, USA.,University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
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5
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Sänger L, Bender J, Rostowski K, Golbik R, Lilie H, Schmidt C, Behrens SE, Friedrich S. Alternatively spliced isoforms of AUF1 regulate a miRNA-mRNA interaction differentially through their YGG motif. RNA Biol 2020; 18:843-853. [PMID: 32924750 DOI: 10.1080/15476286.2020.1822637] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Proper base-pairing of a miRNA with its target mRNA is a key step in miRNA-mediated mRNA repression. RNA remodelling by RNA-binding proteins (RBPs) can improve access of miRNAs to their target mRNAs. The largest isoform p45 of the RBP AUF1 has previously been shown to remodel viral or AU-rich RNA elements. Here, we show that AUF1 is capable of directly promoting the binding of the miRNA let-7b to its target site within the 3'UTR of the POLR2D mRNA. Our data suggest this occurs in two ways. First, the helix-destabilizing RNA chaperone activity of AUF1 disrupts a stem-loop structure of the target mRNA and thus exposes the miRNA target site. Second, the RNA annealing activity of AUF1 drives hybridization of the miRNA and its target site within the mRNA. Interestingly, the RNA remodelling activities of AUF1 were found to be isoform-specific. AUF1 isoforms containing a YGG motif are competent RNA chaperones, whereas isoforms lacking the YGG motif are not. Overall, our study demonstrates that AUF1 has the ability to modulate a miRNA-target site interaction, thus revealing a new regulatory function for AUF1 proteins during post-transcriptional control of gene expression. Moreover, tests with other RBPs suggest the YGG motif acts as a key element of RNA chaperone activity.
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Affiliation(s)
- Lennart Sänger
- Charles Tanford Protein Centre, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Julian Bender
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Centre, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Katja Rostowski
- Charles Tanford Protein Centre, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Ralph Golbik
- Charles Tanford Protein Centre, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Hauke Lilie
- Charles Tanford Protein Centre, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Carla Schmidt
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Centre, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Sven-Erik Behrens
- Charles Tanford Protein Centre, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Susann Friedrich
- Charles Tanford Protein Centre, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
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6
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Ishii T, Sekiguchi M. Two ways of escaping from oxidative RNA damage: Selective degradation and cell death. DNA Repair (Amst) 2019; 81:102666. [PMID: 31326364 DOI: 10.1016/j.dnarep.2019.102666] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Reactive oxygen species (ROS) are produced during normal cellular metabolism, and various oxidized compounds are formed by the ROS attack. Among oxidized bases, 8-oxo-7,8-dihydroguanine (8-oxoG) is most abundant and seems important with respect to the maintenance and transfer of genetic information. The accumulation of 8-oxoG in messenger RNA may cause errors during codon-anticodon pairing in the translation process, which may result in the synthesis of abnormal proteins. Organisms that use oxygen as the source of energy production must therefore have some mechanisms to eliminate the deleterious effects of RNA oxidation. Recently, we found two protein factors, AUF1 and PCBP1, which each have a different binding capacity to oxidized RNA. Evidence demonstrated that AUF1 is involved in the specific degradation of oxidized RNA, and that PCBP1 has a function of inducing cell death to eliminate severely damaged RNA.
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Affiliation(s)
- Takashi Ishii
- Department of Biochemistry, Fukuoka Dental College, Fukuoka 814-0193, Japan.
| | - Mutsuo Sekiguchi
- Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
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7
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Specific binding of PCBP1 to heavily oxidized RNA to induce cell death. Proc Natl Acad Sci U S A 2018; 115:6715-6720. [PMID: 29891675 DOI: 10.1073/pnas.1806912115] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In aerobically growing cells, the guanine base of RNA is oxidized to 8-oxo-7,8-dihydroguanine (8-oxoG), which induces alteration in their gene expression. We previously demonstrated that the human AUF1 protein binds to 8-oxoG in RNA to induce the selective degradation of oxidized messenger RNA. We herein report that the poly(C)-binding protein PCBP1 binds to more severely oxidized RNA to activate apoptosis-related reactions. While AUF1 binds to oligoribonucleotides carrying a single 8-oxoG, PCBP1 does not bind to such oligoribonucleotides but instead binds firmly to oligoribonucleotides in which two 8-oxoG residues are located nearby. PCBP1-deficient cells, constructed from the human HeLa S3 line using the CRISPR-Cas9 system, exhibited higher survival rates than HeLa S3 cells when small doses of hydrogen peroxide were applied. The levels of caspase-3 activation and PARP-1 cleavage in the PCBP1-deficient cells were significantly lower than those in wild-type cells. The structure-function relationship of PCBP1 was established with the use of PCBP1 mutant proteins in which the conserved KH domains were defective. Human cells appear to possess two distinct mechanisms, one controlled by AUF1 and the other by PCBP1, with the former functioning when messenger RNA is moderately oxidized and the latter operating when the RNA is more severely damaged.
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8
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Kishor A, White EJF, Matsangos AE, Yan Z, Tandukar B, Wilson GM. Hsp70's RNA-binding and mRNA-stabilizing activities are independent of its protein chaperone functions. J Biol Chem 2017; 292:14122-14133. [PMID: 28679534 PMCID: PMC5572911 DOI: 10.1074/jbc.m117.785394] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/29/2017] [Indexed: 12/22/2022] Open
Abstract
Hsp70 is a protein chaperone that prevents protein aggregation and aids protein folding by binding to hydrophobic peptide domains through a reversible mechanism directed by an ATPase cycle. However, Hsp70 also binds U-rich RNA including some AU-rich elements (AREs) that regulate the decay kinetics of select mRNAs and has recently been shown to bind and stabilize some ARE-containing transcripts in cells. Previous studies indicated that both the ATP- and peptide-binding domains of Hsp70 contributed to the stability of Hsp70-RNA complexes and that ATP might inhibit RNA recruitment. This suggested the possibility that RNA binding by Hsp70 might mimic features of its peptide-directed chaperone activities. Here, using purified, cofactor-free preparations of recombinant human Hsp70 and quantitative biochemical approaches, we found that high-affinity RNA binding requires at least 30 nucleotides of RNA sequence but is independent of Hsp70's nucleotide-bound status, ATPase activity, or peptide-binding roles. Furthermore, although both the ATP- and peptide-binding domains of Hsp70 could form complexes with an ARE sequence from VEGFA mRNA in vitro, only the peptide-binding domain could recover cellular VEGFA mRNA in ribonucleoprotein immunoprecipitations. Finally, Hsp70-directed stabilization of VEGFA mRNA in cells was mediated exclusively by the protein's peptide-binding domain. Together, these findings indicate that the RNA-binding and mRNA-stabilizing functions of Hsp70 are independent of its protein chaperone cycle but also provide potential mechanical explanations for several well-established and recently discovered cytoprotective and RNA-based Hsp70 functions.
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Affiliation(s)
- Aparna Kishor
- From the Department of Biochemistry and Molecular Biology and Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Elizabeth J F White
- From the Department of Biochemistry and Molecular Biology and Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Aerielle E Matsangos
- From the Department of Biochemistry and Molecular Biology and Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Zisui Yan
- From the Department of Biochemistry and Molecular Biology and Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Bishal Tandukar
- From the Department of Biochemistry and Molecular Biology and Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Gerald M Wilson
- From the Department of Biochemistry and Molecular Biology and Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201.
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Prakash T, Veerappa A, B Ramachandra N. Complex interaction between HNRNPD mutations and risk polymorphisms is associated with discordant Crohn's disease in monozygotic twins. Autoimmunity 2017; 50:275-276. [PMID: 28300425 DOI: 10.1080/08916934.2017.1300883] [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] [Indexed: 10/20/2022]
Abstract
Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) affecting the lining of digestive tracts of the colon and ileum. To investigate the reasons behind the presence of CD phenotype in one of the monozygotic (MZ) twins, we utilized the whole exome sequence (WES) datasets of CD tissue biopsy and CD blood of affected twin and the exome dataset of blood from healthy twin. We report the presence of discordant and rare damaging mutation in HNRNPD and other risk polymorphisms such as, rs12103, rs2241880, rs3810936, rs7076156, rs1042058 and rs1292053. HNRNPD was found carrying two novel heterozygous mutations - a stop gain mutation that truncated the protein at 249th and 268th amino acid position and a single base missense mutation replacing Aspartate with Valine at 300th amino acid. The identified risk polymorphisms were found conferring susceptibility to CD and IBD. Discordant deleterious and damaging mutation was detected in HNRNPD that have been implicated in inflammatory pathways. Integrating these variants led to the elucidation of pathophysiology of CD in the affected twin involving the causal processes of macrophage activation, tissue death, autophagy, immune response, cell-migration and T-cell activation.
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Affiliation(s)
- Tejaswini Prakash
- a Genetics and Genomics Lab, Department of Studies in Genetics and Genomics , University of Mysore , Mysuru , India
| | - Avinash Veerappa
- b Laboratory of Genomic Sciences, Department of Studies in Genetics and Genomics , University of Mysore , Mysuru , India
| | - Nallur B Ramachandra
- a Genetics and Genomics Lab, Department of Studies in Genetics and Genomics , University of Mysore , Mysuru , India
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10
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White EJF, Matsangos AE, Wilson GM. AUF1 regulation of coding and noncoding RNA. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27620010 DOI: 10.1002/wrna.1393] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/09/2016] [Accepted: 08/16/2016] [Indexed: 01/12/2023]
Abstract
AUF1 is a family of four RNA-binding proteins (RBPs) generated by alternative pre-messenger RNA (pre-mRNA) splicing, with canonical roles in controlling the stability and/or translation of mRNA targets based on recognition of AU-rich sequences within mRNA 3' untranslated regions. However, recent studies identifying AUF1 target sites across the transcriptome have revealed that these canonical functions are but a subset of its roles in posttranscriptional regulation of gene expression. In this review, we describe recent developments in our understanding of the RNA-binding properties of AUF1 together with their biochemical implications and roles in directing mRNA decay and translation. This is then followed by a survey of newly discovered activities for AUF1 proteins in control of miRNA synthesis and function, including miRNA assembly into microRNA (miRNA)-loaded RNA-induced silencing complexes (miRISCs), miRISC targeting to mRNA substrates, interplay with an expanding network of other cellular RBPs, and reciprocal regulatory relationships between miRNA and AUF1 synthesis. Finally, we discuss recently reported relationships between AUF1 and long noncoding RNAs and regulatory roles on viral RNA substrates. Cumulatively, these findings have significantly expanded our appreciation of the scope and diversity of AUF1 functions in the cell, and are prompting an exciting array of new questions moving forward. WIREs RNA 2017, 8:e1393. doi: 10.1002/wrna.1393 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Elizabeth J F White
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Aerielle E Matsangos
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Gerald M Wilson
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
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11
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Gunzburg MJ, Sivakumaran A, Pendini NR, Yoon JH, Gorospe M, Wilce MCJ, Wilce JA. Cooperative interplay of let-7 mimic and HuR with MYC RNA. Cell Cycle 2015; 14:2729-33. [PMID: 26177105 DOI: 10.1080/15384101.2015.1069930] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Both RNA-binding proteins (RBP) and miRNA play important roles in the regulation of mRNA expression, often acting together to regulate a target mRNA. In some cases the RBP and miRNA have been reported to act competitively, but in other instances they function cooperatively. Here, we investigated HuR function as an enhancer of let-7-mediated translational repression of c-Myc despite the separation of their binding sites. Using an in vitro system, we determined that a let-7 mimic, consisting of single-stranded (ss)DNA complementary to the let-7 binding site, enhanced the affinity of HuR for a 122-nt MYC RNA encompassing both binding sites. This finding supports the biophysical principle of cooperative binding by an RBP and miRNA purely through interactions at distal mRNA binding sites.
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Affiliation(s)
- Menachem J Gunzburg
- a Biochemistry and Molecular Biology; Monash University ; Melbourne , VIC Australia
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12
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Singh AB, Kan CFK, Shende V, Dong B, Liu J. A novel posttranscriptional mechanism for dietary cholesterol-mediated suppression of liver LDL receptor expression. J Lipid Res 2014; 55:1397-407. [PMID: 24792925 DOI: 10.1194/jlr.m049429] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Indexed: 12/21/2022] Open
Abstract
It is well-established that over-accumulation of dietary cholesterol in the liver inhibits sterol-regulatory element binding protein (SREBP)-mediated LDL receptor (LDLR) gene transcription leading to a reduced hepatic LDLR mRNA level in hypercholesterolemic animals. However, it is unknown whether elevated cholesterol levels can elicit a cellular response to increase LDLR mRNA turnover to further repress LDLR expression in liver tissue. In the current study, we examined the effect of a high cholesterol diet on the hepatic expression of LDLR mRNA binding proteins in three different animal models and in cultured hepatic cells. Our results demonstrate that high cholesterol feeding specifically elevates the hepatic expression of LDLR mRNA decay promoting factor heterogeneous nuclear ribonucleoprotein (HNRNP)D without affecting expressions of other LDLR mRNA binding proteins in vivo and in vitro. Employing the approach of adenovirus-mediated gene knockdown, we further show that depletion of HNRNPD in the liver results in a marked reduction of serum LDL-cholesterol and a substantial increase in liver LDLR expression in hyperlipidemic mice. Additional studies of gene knockdown in albumin-luciferase-untranslated region (UTR) transgenic mice provide strong evidence supporting the essential role of 3'UTR in HNRNPD-mediated LDLR mRNA degradation in liver tissue. Altogether, this work identifies a novel posttranscriptional regulatory mechanism by which dietary cholesterol inhibits liver LDLR expression via inducing HNRNPD to accelerate LDLR mRNA degradation.
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Affiliation(s)
- Amar Bahadur Singh
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 Department of Medicine, Stanford University, Stanford, CA 94305
| | | | - Vikram Shende
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304 Department of Medicine, Stanford University, Stanford, CA 94305
| | - Bin Dong
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304
| | - Jingwen Liu
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304
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13
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Cui Y, Osorio JC, Risquez C, Wang H, Shi Y, Gochuico BR, Morse D, Rosas IO, El-Chemaly S. Transforming growth factor-β1 downregulates vascular endothelial growth factor-D expression in human lung fibroblasts via the Jun NH2-terminal kinase signaling pathway. Mol Med 2014; 20:120-34. [PMID: 24515257 DOI: 10.2119/molmed.2013.00123] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 02/03/2014] [Indexed: 01/28/2023] Open
Abstract
Vascular endothelial growth factor (VEGF)-D, a member of the VEGF family, induces both angiogenesis and lymphangiogenesis by activating VEGF receptor-2 (VEGFR-2) and VEGFR-3 on the surface of endothelial cells. Transforming growth factor (TGF)-β1 has been shown to stimulate VEGF-A expression in human lung fibroblast via the Smad3 signaling pathway and to induce VEGF-C in human proximal tubular epithelial cells. However, the effects of TGF-β1 on VEGF-D regulation are unknown. To investigate the regulation of VEGF-D, human lung fibroblasts were studied under pro-fibrotic conditions in vitro and in idiopathic pulmonary fibrosis (IPF) lung tissue. We demonstrate that TGF-β1 downregulates VEGF-D expression in a dose- and time-dependent manner in human lung fibroblasts. This TGF-β1 effect can be abolished by inhibitors of TGF-β type I receptor kinase and Jun NH2-terminal kinase (JNK), but not by Smad3 knockdown. In addition, VEGF-D knockdown in human lung fibroblasts induces G1/S transition and promotes cell proliferation. Importantly, VEGF-D protein expression is decreased in lung homogenates from IPF patients compared with control lung. In IPF lung sections, fibroblastic foci show very weak VEGF-D immunoreactivity, whereas VEGF-D is abundantly expressed within alveolar interstitial cells in control lung. Taken together, our data identify a novel mechanism for downstream signal transduction induced by TGF-β1 in lung fibroblasts, through which they may mediate tissue remodeling in IPF.
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Affiliation(s)
- Ye Cui
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Juan C Osorio
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Cristobal Risquez
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hao Wang
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ying Shi
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bernadette R Gochuico
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Danielle Morse
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ivan O Rosas
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Souheil El-Chemaly
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
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