1
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Ćuk M, Lovrenčić L, Unal B, Walker M, Hayes CP, Krakar G, Beluzić R, Sansović I, Pavliša G, Ghazani AA. Novel de Novo Nonsense Variants in AGO3 and KHSRP: Insights into Global Developmental Delay and Autism Spectrum Disorders through Whole Genome Analysis. AMERICAN JOURNAL OF CASE REPORTS 2024; 25:e943641. [PMID: 38995884 PMCID: PMC11315612 DOI: 10.12659/ajcr.943641] [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: 12/28/2023] [Revised: 06/07/2024] [Accepted: 04/09/2024] [Indexed: 07/14/2024]
Abstract
BACKGROUND Neurodevelopmental disorders (NDD) are umbrella disorders that encompass global developmental delay (GDD), intellectual disability, autism spectrum disorders, motor developmental disorders, and sleep disorders. Both GDD and autism spectrum disorder are common and yet clinically and genetically heterogeneous disorders. Despite their high prevalence and the advent of sequencing detection methods, the genomic etiology of GDD and autism spectrum disorder in most patients is largely unknown. CASE REPORT In this study, we describe a 6-year-old girl with GDD, autistic features, and structural brain abnormalities, including a moderate reduction in periventricular white matter and bilateral optic nerve hypoplasia, Chiari malformation type I with normal myelinization. A comprehensive joint whole-genome analysis (WGS) of the proband and her unaffected parents was performed. The trio-WGS analysis identified novel de novo nonsense variants AGO3: c.1324C>T (p.Gln442*) and KHSRP: c.1573C>T (p.Gln525*). These variants have not been reported in gnomAD and published literature. AGO3 and KHSRP are not currently associated with a known phenotype in the Online Mendelian Inheritance in Man (OMIM); however, they may be involved in neuronal development. CONCLUSIONS This report highlights the utility of joint WGS analysis in identifying novel de novo genomic alterations in a patient with the spectrum of phenotypes of GDD and neurodevelopmental disorders. The role of these variants and genes in GDD requires further studies.
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Affiliation(s)
- Mario Ćuk
- Department of Pediatrics, University Hospital Centre Zagreb and University of Zagreb, School of Medicine, Zagreb, Croatia
| | - Luka Lovrenčić
- Department of Pediatrics, University Hospital Centre Zagreb and University of Zagreb, School of Medicine, Zagreb, Croatia
| | - Busra Unal
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA, USA
| | - McKenzie Walker
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA, USA
| | - Connor P. Hayes
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA, USA
| | - Goran Krakar
- Department of Child Neurology, Pediatric Clinic Sabol, Croatia Rudjer Boskovic Institute, Zagreb, Croatia
| | - Robert Beluzić
- Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Ivona Sansović
- Department of Medica and Laboratory Genetics, Endocrinology and Diabetology, Children’s Hospital Zagreb, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Goran Pavliša
- Department for Diagnostic and Interventional Neuroradiology, University Hospital Centre Zagreb, and University of Zagreb, School of Medicine, Zagreb, Croatia
| | - Arezou A. Ghazani
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA, USA
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
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2
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Herbert A. The ancient Z-DNA and Z-RNA specific Zα fold has evolved modern roles in immunity and transcription through the natural selection of flipons. ROYAL SOCIETY OPEN SCIENCE 2024; 11:240080. [PMID: 39092141 PMCID: PMC11293857 DOI: 10.1098/rsos.240080] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/29/2024] [Accepted: 05/08/2024] [Indexed: 08/04/2024]
Abstract
The Zα fold specifically binds to both Z-DNA and Z-RNA, left-handed nucleic acid structures that form under physiological conditions and are encoded by flipons. I trace the Zα fold back to unicellular organisms representing all three domains of life and to the realm of giant nucleocytoplasmic DNA viruses (NCVs). The canonical Zα fold is present in the earliest known holozoan unicellular symbiont Capsaspora owczarzaki and persists in vertebrates and some invertebrates, but not in plants or fungi. In metazoans, starting with porifera, Zα is incorporated into the double-stranded RNA editing enzyme ADAR and reflects an early symbiont relationship with NCV. In vertebrates, Zα is also present in ZBP1 and PKZ proteins that recognize host-derived Z-RNAs to defend against modern-day viruses. A related Zα fold, also likely to bind Z-DNA, is present in proteins thought to modulate gene expression, including a subset of prokaryote arsR proteins and the p15 (PC4) family present in algae. Other Zα variants that probably play a more general role in the reinitiation of transcription include the archaeal and human transcription factor E and the human RNA polymerase 3 subunit C proteins. The roles in immunity and transcription underlie the natural selection of flipons.
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Affiliation(s)
- Alan Herbert
- Discovery, InsideOutBio, 42 8th Street, Charlestown, MA02129, USA
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3
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Nakanishi K. When Argonaute takes out the ribonuclease sword. J Biol Chem 2024; 300:105499. [PMID: 38029964 PMCID: PMC10772731 DOI: 10.1016/j.jbc.2023.105499] [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: 07/10/2023] [Revised: 11/11/2023] [Accepted: 11/15/2023] [Indexed: 12/01/2023] Open
Abstract
Argonaute (AGO) proteins in all three domains of life form ribonucleoprotein or deoxyribonucleoprotein complexes by loading a guide RNA or DNA, respectively. Since all AGOs retain a PIWI domain that takes an RNase H fold, the ancestor was likely an endoribonuclease (i.e., a slicer). In animals, most miRNA-mediated gene silencing occurs slicer independently. However, the slicer activity of AGO is indispensable in specific events, such as development and differentiation, which are critical for vertebrates and thus cannot be replaced by the slicer-independent regulation. This review highlights the distinctions in catalytic activation mechanisms among slicing-competent AGOs, shedding light on the roles of two metal ions in target recognition and cleavage. The precision of the target specificity by the RNA-induced silencing complexes is reevaluated and redefined. The possible coevolutionary relationship between slicer-independent gene regulation and AGO-binding protein, GW182, is also explored. These discussions reveal that numerous captivating questions remain unanswered regarding the timing and manner in which AGOs employ their slicing activity.
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Affiliation(s)
- Kotaro Nakanishi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.
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4
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Guidi R, Wedeles C, Xu D, Kolmus K, Headland SE, Teng G, Guillory J, Zeng YJ, Cheung TK, Chaudhuri S, Modrusan Z, Liang Y, Horswell S, Haley B, Rutz S, Rose C, Franke Y, Kirkpatrick DS, Hackney JA, Wilson MS. Argonaute3-SF3B3 complex controls pre-mRNA splicing to restrain type 2 immunity. Cell Rep 2023; 42:113515. [PMID: 38096048 DOI: 10.1016/j.celrep.2023.113515] [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: 02/14/2023] [Revised: 08/28/2023] [Accepted: 11/15/2023] [Indexed: 12/30/2023] Open
Abstract
Argonaute (AGO) proteins execute microRNA (miRNA)-mediated gene silencing. However, it is unclear whether all 4 mammalian AGO proteins (AGO1, AGO2, AGO3, and AGO4) are required for miRNA activity. We generate Ago1, Ago3, and Ago4-deficient mice (Ago134Δ) and find AGO1/3/4 to be redundant for miRNA biogenesis, homeostasis, or function, a role that is carried out by AGO2. Instead, AGO1/3/4 regulate the expansion of type 2 immunity via precursor mRNA splicing in CD4+ T helper (Th) lymphocytes. Gain- and loss-of-function experiments demonstrate that nuclear AGO3 interacts directly with SF3B3, a component of the U2 spliceosome complex, to aid global mRNA splicing, and in particular the isoforms of the gene Nisch, resulting in a dysregulated Nisch isoform ratio. This work uncouples AGO1, AGO3, and AGO4 from miRNA-mediated RNA interference, identifies an AGO3:SF3B3 complex in the nucleus, and reveals a mechanism by which AGO proteins regulate inflammatory diseases.
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Affiliation(s)
- Riccardo Guidi
- Immunology Discovery, Genentech, South San Francisco, CA 94080, USA
| | | | - Daqi Xu
- Immunology Discovery, Genentech, South San Francisco, CA 94080, USA
| | - Krzysztof Kolmus
- OMNI Bioinformatics, Genentech, South San Francisco, CA 94080, USA
| | - Sarah E Headland
- Immunology Discovery, Genentech, South San Francisco, CA 94080, USA
| | - Grace Teng
- Immunology Discovery, Genentech, South San Francisco, CA 94080, USA
| | - Joseph Guillory
- Next Generation Sequencing (NGS), Genentech, South San Francisco, CA 94080, USA
| | - Yi Jimmy Zeng
- Microchemistry, Proteomics and Lipidomics, Genentech, South San Francisco, CA 94080, USA
| | - Tommy K Cheung
- Microchemistry, Proteomics and Lipidomics, Genentech, South San Francisco, CA 94080, USA
| | - Subhra Chaudhuri
- Next Generation Sequencing (NGS), Genentech, South San Francisco, CA 94080, USA
| | - Zora Modrusan
- Next Generation Sequencing (NGS), Genentech, South San Francisco, CA 94080, USA
| | - Yuxin Liang
- Next Generation Sequencing (NGS), Genentech, South San Francisco, CA 94080, USA
| | - Stuart Horswell
- Bioinformatic and Biostatistics, The Francis Crick Institute, London, UK
| | - Benjamin Haley
- Molecular Biology, Genentech, South San Francisco, CA 94080, USA
| | - Sascha Rutz
- Cancer Immunology, Genentech, South San Francisco, CA 94080, USA
| | - Christopher Rose
- Microchemistry, Proteomics and Lipidomics, Genentech, South San Francisco, CA 94080, USA
| | - Yvonne Franke
- Protein Sciences, Genentech, South San Francisco, CA 94080, USA
| | - Donald S Kirkpatrick
- Microchemistry, Proteomics and Lipidomics, Genentech, South San Francisco, CA 94080, USA
| | - Jason A Hackney
- OMNI Bioinformatics, Genentech, South San Francisco, CA 94080, USA
| | - Mark S Wilson
- Immunology Discovery, Genentech, South San Francisco, CA 94080, USA.
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5
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Khan M, Shah S, Lv B, Lv Z, Ji N, Song Z, Wu P, Wang X, Mehmood A. Molecular Mechanisms of Alu and LINE-1 Interspersed Repetitive Sequences Reveal Diseases of Visual System Dysfunction. Ocul Immunol Inflamm 2023; 31:1848-1858. [PMID: 36040959 DOI: 10.1080/09273948.2022.2112238] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 08/05/2022] [Indexed: 10/14/2022]
Abstract
BACKGROUND Short interspersed nuclear elements (SINEs) and long interspersed nuclear elements (LINE-1s) are the abundant and well-characterized repetitive elements in the human genome. METHODS For this review, all relevant original research studies were assessed by searching electronic databases, including PubMed, Google Scholar, and Web of Science, by using relevant keywords. Accumulating evidence indicates that the disorder of gene expression regulated by these repetitive sequences is one of the causes of the diseases of visual system dysfunction, including retinal degenerations, glaucoma, retinitis punctata albescens, retinitis pigmentosa, geographic atrophy, and age-related macular degeneration, suggesting that SINEs and LINE-1s may have great potential implications in ophthalmology. RESULTS Alu elements belonging to the SINEs are present in more than one million copies, comprising 10% of the human genome. CONCLUSION This study offers recent advances in Alu and LINE-1 mechanisms in the development of eye diseases. The current study could advance our knowledge of the roles of SINEs and LINE-1s in the developing process of eye diseases, suggesting new diagnostic biomarkers, therapeutic strategies, and significant points for future studies.
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Affiliation(s)
- Murad Khan
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China
| | - Suleman Shah
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China
| | - Baixue Lv
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, Hubei Province, China
| | - Zhanjun Lv
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China
| | - Ning Ji
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China
| | - Zhixue Song
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China
| | - Peiyuan Wu
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China
| | - Xiufang Wang
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, Hebei Province, China
| | - Arshad Mehmood
- Department of Neurology, the Second Hospital of Hebei Medical University, City Shijiazhuang, P.R. China
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6
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Weigert N, Schweiger AL, Gross J, Matthes M, Corbacioglu S, Sommer G, Heise T. Detection of a 7SL RNA-derived small non-coding RNA using Molecular Beacons in vitro and in cells. Biol Chem 2023; 404:1123-1136. [PMID: 37632732 DOI: 10.1515/hsz-2023-0185] [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: 04/14/2023] [Accepted: 08/11/2023] [Indexed: 08/28/2023]
Abstract
Small non-coding RNAs (sncRNA) are involved in many steps of the gene expression cascade and regulate processing and expression of mRNAs by the formation of ribonucleoprotein complexes (RNP) such as the RNA-induced silencing complex (RISC). By analyzing small RNA Seq data sets, we identified a sncRNA annotated as piR-hsa-1254, which is likely derived from the 3'-end of 7SL RNA2 (RN7SL2), herein referred to as snc7SL RNA. The 7SL RNA is an abundant long non-coding RNA polymerase III transcript and serves as structural component of the cytoplasmic signal recognition particle (SRP). To evaluate a potential functional role of snc7SL RNA, we aimed to define its cellular localization by live cell imaging. Therefore, a Molecular Beacon (MB)-based method was established to compare the subcellular localization of snc7SL RNA with its precursor 7SL RNA. We designed and characterized several MBs in vitro and tested those by live cell fluorescence microscopy. Using a multiplex approach, we show that 7SL RNA localizes mainly to the endoplasmic reticulum (ER), as expected for the SRP, whereas snc7SL RNA predominately localizes to the nucleus. This finding suggests a fundamentally different function of 7SL RNA and its derivate snc7SL RNA.
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Affiliation(s)
- Nina Weigert
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Franz-Josef-Strauß Allee 11, D-93053 Regensburg, Germany
| | - Anna-Lena Schweiger
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Franz-Josef-Strauß Allee 11, D-93053 Regensburg, Germany
| | - Jonas Gross
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Franz-Josef-Strauß Allee 11, D-93053 Regensburg, Germany
| | - Marie Matthes
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Franz-Josef-Strauß Allee 11, D-93053 Regensburg, Germany
| | - Selim Corbacioglu
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Franz-Josef-Strauß Allee 11, D-93053 Regensburg, Germany
| | - Gunhild Sommer
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Franz-Josef-Strauß Allee 11, D-93053 Regensburg, Germany
| | - Tilman Heise
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Franz-Josef-Strauß Allee 11, D-93053 Regensburg, Germany
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7
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Wang J, Weatheritt R, Voineagu I. Alu-minating the Mechanisms Underlying Primate Cortex Evolution. Biol Psychiatry 2022; 92:760-771. [PMID: 35981906 DOI: 10.1016/j.biopsych.2022.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 04/04/2022] [Accepted: 04/28/2022] [Indexed: 11/02/2022]
Abstract
The higher-order cognitive functions observed in primates correlate with the evolutionary enhancement of cortical volume and folding, which in turn are driven by the primate-specific expansion of cellular diversity in the developing cortex. Underlying these changes is the diversification of molecular features including the creation of human and/or primate-specific genes, the activation of specific molecular pathways, and the interplay of diverse layers of gene regulation. We review and discuss evidence for connections between Alu elements and primate brain evolution, the evolutionary milestones of which are known to coincide along primate lineages. Alus are repetitive elements that contribute extensively to the acquisition of novel genes and the expansion of diverse gene regulatory layers, including enhancers, alternative splicing, RNA editing, and microRNA pathways. By reviewing the impact of Alus on molecular features linked to cortical expansions or gyrification or implications in cognitive deficits, we suggest that future research focusing on the role of Alu-derived molecular events in the context of brain development may greatly advance our understanding of higher-order cognitive functions and neurologic disorders.
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Affiliation(s)
- Juli Wang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia.
| | - Robert Weatheritt
- St Vincent Clinical School, University of New South Wales, Sydney, Australia; Garvan Institute of Medical Research, EMBL Australia, Sydney, New South Wales, Australia
| | - Irina Voineagu
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia; Cellular Genomics Futures Institute, University of New South Wales, Sydney, Australia.
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8
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Nakanishi K. Anatomy of four human Argonaute proteins. Nucleic Acids Res 2022; 50:6618-6638. [PMID: 35736234 PMCID: PMC9262622 DOI: 10.1093/nar/gkac519] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 12/24/2022] Open
Abstract
MicroRNAs (miRNAs) bind to complementary target RNAs and regulate their gene expression post-transcriptionally. These non-coding regulatory RNAs become functional after loading into Argonaute (AGO) proteins to form the effector complexes. Humans have four AGO proteins, AGO1, AGO2, AGO3 and AGO4, which share a high sequence identity. Since most miRNAs are found across the four AGOs, it has been thought that they work redundantly, and AGO2 has been heavily studied as the exemplified human paralog. Nevertheless, an increasing number of studies have found that the other paralogs play unique roles in various biological processes and diseases. In the last decade, the structural study of the four AGOs has provided the field with solid structural bases. This review exploits the completed structural catalog to describe common features and differences in target specificity across the four AGOs.
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Affiliation(s)
- Kotaro Nakanishi
- To whom correspondence should be addressed. Tel: +1 614 688 2188;
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9
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Guo YL, Gurung C, Fendereski M, Huang F. Dicer and PKR as Novel Regulators of Embryonic Stem Cell Fate and Antiviral Innate Immunity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:2259-2266. [PMID: 35577384 PMCID: PMC9179006 DOI: 10.4049/jimmunol.2200042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/21/2022] [Indexed: 05/17/2023]
Abstract
Embryonic stem cells (ESCs) represent a unique cell population in the blastocyst stage embryo. They have been intensively studied as a promising cell source for regenerative medicine. Recent studies have revealed that both human and mouse ESCs are deficient in expressing IFNs and have attenuated inflammatory responses. Apparently, the ability to express IFNs and respond to certain inflammatory cytokines is not "innate" to ESCs but rather is developmentally acquired by somatic cells during differentiation. Accumulating evidence supports a hypothesis that the attenuated innate immune response may serve as a protective mechanism allowing ESCs to avoid immunological cytotoxicity. This review describes our current understanding of the molecular basis that shapes the immune properties of ESCs. We highlight the recent findings on Dicer and dsRNA-activated protein kinase R as novel regulators of ESC fate and antiviral immunity and discuss how ESCs use alternative mechanisms to accommodate their stem cell properties.
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Affiliation(s)
- Yan-Lin Guo
- Cell and Molecular Biology Program, University of Southern Mississippi, Hattiesburg, MS; and
| | - Chandan Gurung
- Cell and Molecular Biology Program, University of Southern Mississippi, Hattiesburg, MS; and
| | - Mona Fendereski
- Cell and Molecular Biology Program, University of Southern Mississippi, Hattiesburg, MS; and
| | - Faqing Huang
- Chemistry and Biochemistry Program, University of Southern Mississippi, Hattiesburg, MS
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10
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Li M, Larsen PA. Primate-specific retrotransposons and the evolution of circadian networks in the human brain. Neurosci Biobehav Rev 2021; 131:988-1004. [PMID: 34592258 DOI: 10.1016/j.neubiorev.2021.09.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 08/03/2021] [Accepted: 09/26/2021] [Indexed: 11/26/2022]
Abstract
The circadian rhythm of the human brain is attuned to sleep-wake cycles that entail global alterations in neuronal excitability. This periodicity involves a highly coordinated regulation of gene expression. A growing number of studies are documenting a fascinating connection between primate-specific retrotransposons (Alu elements) and key epigenetic regulatory processes in the primate brain. Collectively, these studies indicate that Alu elements embedded in the human neuronal genome mediate post-transcriptional processes that unite human-specific neuroepigenetic landscapes and circadian rhythm. Here, we review evidence linking Alu retrotransposon-mediated posttranscriptional pathways to circadian gene expression. We hypothesize that Alu retrotransposons participate in the organization of circadian brain function through multidimensional neuroepigenetic pathways. We anticipate that these pathways are closely tied to the evolution of human cognition and their perturbation contributes to the manifestation of human-specific neurological diseases. Finally, we address current challenges and accompanying opportunities in studying primate- and human-specific transposable elements.
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Affiliation(s)
- Manci Li
- University of Minnesota, St. Paul, MN, 55108, United States
| | - Peter A Larsen
- University of Minnesota, St. Paul, MN, 55108, United States.
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11
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Tang D, Zhang Z, Zboril E, Wetzel MD, Xu X, Zhang W, Chen L, Liu Z. Pontin Functions as A Transcriptional Co-activator for Retinoic Acid-induced HOX Gene Expression. J Mol Biol 2021; 433:166928. [PMID: 33713676 PMCID: PMC8184613 DOI: 10.1016/j.jmb.2021.166928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/18/2021] [Accepted: 03/04/2021] [Indexed: 12/12/2022]
Abstract
Pontin is a AAA+ ATPase protein that has functions in various biological contexts including gene transcription regulation, chromatin remodeling, DNA damage sensing and repair, as well as assembly of protein and ribonucleoprotein complexes. Pontin is known to regulate the transcription of several important signaling pathways, including Wnt signaling. However, its role in early embryonic signaling regulation remains unclear. Retinoic acid (RA) signaling plays a central role in vertebrate development. Using an in vivo biotin tagging technology, we mapped the genome-wide binding pattern of Pontin before and after RA-induced differentiation in the pluripotent embryo carcinoma cell line NTERA-2. Biotin ChIP-seq revealed significant changes in genome-wide Pontin binding sites upon RA stimulation. We also identified a substantial amount of overlapping binding peaks between Pontin and RARα, especially on all of the HOX gene loci (A-D clusters). Pontin knockdown experiments showed that its chromatin binding at the HOX gene clusters is required for RA-induced HOX gene expression. Furthermore, we performed Global Run-On sequencing (GRO-seq) to map de novo transcripts genome-wide and found that Pontin knockdown significantly diminished nascent HOX gene transcripts, indicating that Pontin regulates HOX gene expression at the transcriptional level. Finally, proteomic analysis demonstrated that Pontin associates with chromatin organization/remodeling complexes and various other functional complexes. Altogether, we have demonstrated that Pontin is a critical transcriptional co-activator for RA-induced HOX gene activation.
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Affiliation(s)
- Dan Tang
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Department of General Practice, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - Zhao Zhang
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Emily Zboril
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Michael D Wetzel
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Xinping Xu
- Jiangxi Institute of Respiratory Disease, The Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - Wei Zhang
- Jiangxi Institute of Respiratory Disease, The Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - Lizhen Chen
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Zhijie Liu
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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12
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Luo QJ, Zhang J, Li P, Wang Q, Zhang Y, Roy-Chaudhuri B, Xu J, Kay MA, Zhang QC. RNA structure probing reveals the structural basis of Dicer binding and cleavage. Nat Commun 2021; 12:3397. [PMID: 34099665 PMCID: PMC8184798 DOI: 10.1038/s41467-021-23607-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/03/2021] [Indexed: 01/27/2023] Open
Abstract
It is known that an RNA's structure determines its biological function, yet current RNA structure probing methods only capture partial structure information. The ability to measure intact (i.e., full length) RNA structures will facilitate investigations of the functions and regulation mechanisms of small RNAs and identify short fragments of functional sites. Here, we present icSHAPE-MaP, an approach combining in vivo selective 2'-hydroxyl acylation and mutational profiling to probe intact RNA structures. We further showcase the RNA structural landscape of substrates bound by human Dicer based on the combination of RNA immunoprecipitation pull-down and icSHAPE-MaP small RNA structural profiling. We discover distinct structural categories of Dicer substrates in correlation to both their binding affinity and cleavage efficiency. And by tertiary structural modeling constrained by icSHAPE-MaP RNA structural data, we find the spatial distance measuring as an influential parameter for Dicer cleavage-site selection.
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Affiliation(s)
- Qing-Jun Luo
- Department of Pediatrics, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Jinsong Zhang
- Ministry of Education Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Pan Li
- Ministry of Education Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Qing Wang
- Department of Pediatrics, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
- Faculty of Preventive Medicine, A Key Laboratory of Guangzhou Environmental Pollution and Risk Assessment, School of Public Health, Sun Yat-Sen University, Guangzhou, China
| | - Yue Zhang
- Department of Pediatrics, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
- Freenome Holdings Inc., South San Francisco, CA, USA
| | - Biswajoy Roy-Chaudhuri
- Department of Pediatrics, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
- Impossible Foods Inc., Redwood City, CA, USA
| | - Jianpeng Xu
- Department of Pediatrics, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Mark A Kay
- Department of Pediatrics, Stanford University, Stanford, CA, USA.
- Department of Genetics, Stanford University, Stanford, CA, USA.
| | - Qiangfeng Cliff Zhang
- Ministry of Education Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
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13
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Ambati J, Magagnoli J, Leung H, Wang SB, Andrews CA, Fu D, Pandey A, Sahu S, Narendran S, Hirahara S, Fukuda S, Sun J, Pandya L, Ambati M, Pereira F, Varshney A, Cummings T, Hardin JW, Edun B, Bennett CL, Ambati K, Fowler BJ, Kerur N, Röver C, Leitinger N, Werner BC, Stein JD, Sutton SS, Gelfand BD. Repurposing anti-inflammasome NRTIs for improving insulin sensitivity and reducing type 2 diabetes development. Nat Commun 2020; 11:4737. [PMID: 32968070 PMCID: PMC7511405 DOI: 10.1038/s41467-020-18528-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 08/27/2020] [Indexed: 12/20/2022] Open
Abstract
Innate immune signaling through the NLRP3 inflammasome is activated by multiple diabetes-related stressors, but whether targeting the inflammasome is beneficial for diabetes is still unclear. Nucleoside reverse-transcriptase inhibitors (NRTI), drugs approved to treat HIV-1 and hepatitis B infections, also block inflammasome activation. Here, we show, by analyzing five health insurance databases, that the adjusted risk of incident diabetes is 33% lower in patients with NRTI exposure among 128,861 patients with HIV-1 or hepatitis B (adjusted hazard ratio for NRTI exposure, 0.673; 95% confidence interval, 0.638 to 0.710; P < 0.0001; 95% prediction interval, 0.618 to 0.734). Meanwhile, an NRTI, lamivudine, improves insulin sensitivity and reduces inflammasome activation in diabetic and insulin resistance-induced human cells, as well as in mice fed with high-fat chow; mechanistically, inflammasome-activating short interspersed nuclear element (SINE) transcripts are elevated, whereas SINE-catabolizing DICER1 is reduced, in diabetic cells and mice. These data suggest the possibility of repurposing an approved class of drugs for prevention of diabetes.
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Affiliation(s)
- Jayakrishna Ambati
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA.
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA.
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, USA.
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA, USA.
| | - Joseph Magagnoli
- Dorn Research Institute, Columbia VA Health Care System, Columbia, SC, USA
- Department of Clinical Pharmacy & Outcomes Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA
| | - Hannah Leung
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Shao-Bin Wang
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Chris A Andrews
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI, USA
- Center for Eye Policy and Innovation, University of Michigan, Ann Arbor, MI, USA
| | - Dongxu Fu
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Akshat Pandey
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Srabani Sahu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Siddharth Narendran
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Shuichiro Hirahara
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Shinichi Fukuda
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Tsukuba, Ibaraki, Japan
| | - Jian Sun
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Lekha Pandya
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Meenakshi Ambati
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Felipe Pereira
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Akhil Varshney
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Tammy Cummings
- Dorn Research Institute, Columbia VA Health Care System, Columbia, SC, USA
- Department of Clinical Pharmacy & Outcomes Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA
| | - James W Hardin
- Department of Epidemiology & Biostatistics, University of South Carolina, Columbia, SC, USA
| | - Babatunde Edun
- Dorn Research Institute, Columbia VA Health Care System, Columbia, SC, USA
- Department of Medicine, Baystate Medical Center, Springfield, MA, USA
| | - Charles L Bennett
- Dorn Research Institute, Columbia VA Health Care System, Columbia, SC, USA
- Department of Clinical Pharmacy & Outcomes Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA
- Center for Medication Safety and Efficacy, College of Pharmacy, University of South Carolina, Columbia, SC, USA
| | - Kameshwari Ambati
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Benjamin J Fowler
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY, USA
| | - Nagaraj Kerur
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Christian Röver
- Department of Medical Statistics, University Medical Center Göttingen, Göttingen, Germany
| | - Norbert Leitinger
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Brian C Werner
- Department of Orthopaedics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Joshua D Stein
- Department of Clinical Pharmacy & Outcomes Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Health Management and Policy, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - S Scott Sutton
- Dorn Research Institute, Columbia VA Health Care System, Columbia, SC, USA
- Department of Clinical Pharmacy & Outcomes Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, USA
| | - Bradley D Gelfand
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, VA, USA
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14
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From the Argonauts Mythological Sailors to the Argonautes RNA-Silencing Navigators: Their Emerging Roles in Human-Cell Pathologies. Int J Mol Sci 2020; 21:ijms21114007. [PMID: 32503341 PMCID: PMC7312461 DOI: 10.3390/ijms21114007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 12/27/2022] Open
Abstract
Regulation of gene expression has emerged as a fundamental element of transcript homeostasis. Key effectors in this process are the Argonautes (AGOs), highly specialized RNA-binding proteins (RBPs) that form complexes, such as the RNA-Induced Silencing Complex (RISC). AGOs dictate post-transcriptional gene-silencing by directly loading small RNAs and repressing their mRNA targets through small RNA-sequence complementarity. The four human highly-conserved family-members (AGO1, AGO2, AGO3, and AGO4) demonstrate multi-faceted and versatile roles in transcriptome’s stability, plasticity, and functionality. The post-translational modifications of AGOs in critical amino acid residues, the nucleotide polymorphisms and mutations, and the deregulation of expression and interactions are tightly associated with aberrant activities, which are observed in a wide spectrum of pathologies. Through constantly accumulating information, the AGOs’ fundamental engagement in multiple human diseases has recently emerged. The present review examines new insights into AGO-driven pathology and AGO-deregulation patterns in a variety of diseases such as in viral infections and propagations, autoimmune diseases, cancers, metabolic deficiencies, neuronal disorders, and human infertility. Altogether, AGO seems to be a crucial contributor to pathogenesis and its targeting may serve as a novel and powerful therapeutic tool for the successful management of diverse human diseases in the clinic.
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15
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AP-TSS: A New Method for the Analysis of RNA Expression from Particular and Challenging Transcription Start Sites. Biomolecules 2020; 10:biom10060827. [PMID: 32481529 PMCID: PMC7355800 DOI: 10.3390/biom10060827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/12/2020] [Accepted: 05/21/2020] [Indexed: 11/25/2022] Open
Abstract
Alternative promoter usage involved in the regulation of transcription, splicing, and translation contributes to proteome diversity and is involved in a large number of diseases, in particular, cancer. Epigenetic mechanisms and cis regulatory elements are involved in alternative promoter activity. Multiple transcript isoforms can be produced from a gene, due to the initiation of transcription at different transcription start sites (TSS). These transcripts may not have regions that allow discrimination during RT-qPCR, making quantification technically challenging. This study presents a general method for the relative quantification of a transcript synthesized from a particular TSS that we called AP-TSS (analysis of particular TSS). AP-TSS is based on the specific elongation of the cDNA of interest, followed by its quantification by qPCR. As proof of principle, AP-TSS was applied to two non-coding RNA: telomeric repeat-containing RNAs (TERRA) from a particular subtelomeric TSS, and Alu transcripts. The treatment of cells with a DNA methylation inhibitor was associated with a global increase of the total TERRA level, but the TERRA expression from the TSS of interest did not change in HT1080 cells, and only modestly increased in HeLa cells. This result suggests that TERRA upregulation induced by global demethylation of the genome is mainly due to activation from sites other than this particular TSS. For Alu RNA, the signal obtained by AP-TSS is specific for the RNA Polymerase III-dependent Alu transcript. In summary, our method provides a tool to study regulation of gene expression from a given transcription start site, in different conditions that could be applied to many genes. In particular, AP-TSS can be used to investigate the epigenetic regulation of alternative TSS usage that is of importance for the development of epigenetic-targeted therapies.
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16
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Subhramanyam CS, Cao Q, Wang C, Heng ZSL, Zhou Z, Hu Q. Role of PIWI-like 4 in modulating neuronal differentiation from human embryonal carcinoma cells. RNA Biol 2020; 17:1613-1624. [PMID: 32372724 DOI: 10.1080/15476286.2020.1757896] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PIWI homologs constitute a subclass of the Argonaute family. Traditionally, they have been shown to associate with a specific class of small RNAs, piRNAs, to suppress transposable elements and protect genomic integrity in germ cells. Recent studies imply that PIWI proteins may also exert important biological functions in somatic contexts, including the brain. However, their exact role in neural development remains unknown. Hence we investigated whether PIWI proteins are involved in neuronal differentiation. By using an established cell model for studying neurogenesis, NTera2/D1 (NT2) cells, we found that a particular PIWI homolog, PIWIL4 was increasingly upregulated throughout the course of all-trans retinoic acid (RA)-mediated neuronal differentiation. During this process, PIWIL4 knockdown led to partial recovery of embryonic stem cell markers, while suppressing RA-induced expression of neuronal markers. Consistently, PIWIL4 overexpression further elevated their expression levels. Furthermore, co-immunoprecipitation revealed an RA-induced interaction between PIWIL4 and the H3K27me3 demethylase UTX. Chromatin immunoprecipitation showed that this interaction could be essential for the removal of H3K27me3 from the promoters of RA-inducible genes. By a similar mechanism, PIWIL4 knockdown also suppressed the expression of PTN and NLGN3, two important neuronal factors secreted to regulate glioma activity. We further noted that the conditioned medium collected from PIWIL4-silenced NT2 cells significantly reduced the proliferation of glioma cells. Thus, our data suggest a novel somatic role of PIWIL4 in modulating the expression of neuronal genes that can be further characterized to promote neuronal differentiation and to modulate the activity of glioma cells.
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Affiliation(s)
| | - Qiong Cao
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore , Singapore
| | - Cheng Wang
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore , Singapore
| | - Zealyn Shi Lin Heng
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore , Singapore
| | - Zhihong Zhou
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore , Singapore
| | - Qidong Hu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore , Singapore
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17
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Wright CB, Uehara H, Kim Y, Yasuma T, Yasuma R, Hirahara S, Makin RD, Apicella I, Pereira F, Nagasaka Y, Narendran S, Fukuda S, Albuquerque R, Fowler BJ, Bastos-Carvalho A, Georgel P, Hatada I, Chang B, Kerur N, Ambati BK, Ambati J, Gelfand BD. Chronic Dicer1 deficiency promotes atrophic and neovascular outer retinal pathologies in mice. Proc Natl Acad Sci U S A 2020; 117:2579-2587. [PMID: 31964819 PMCID: PMC7007521 DOI: 10.1073/pnas.1909761117] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Degeneration of the retinal pigmented epithelium (RPE) and aberrant blood vessel growth in the eye are advanced-stage processes in blinding diseases such as age-related macular degeneration (AMD), which affect hundreds of millions of people worldwide. Loss of the RNase DICER1, an essential factor in micro-RNA biogenesis, is implicated in RPE atrophy. However, the functional implications of DICER1 loss in choroidal and retinal neovascularization are unknown. Here, we report that two independent hypomorphic mouse strains, as well as a separate model of postnatal RPE-specific DICER1 ablation, all presented with spontaneous RPE degeneration and choroidal and retinal neovascularization. DICER1 hypomorphic mice lacking critical inflammasome components or the innate immune adaptor MyD88 developed less severe RPE atrophy and pathological neovascularization. DICER1 abundance was also reduced in retinas of the JR5558 mouse model of spontaneous choroidal neovascularization. Finally, adenoassociated vector-mediated gene delivery of a truncated DICER1 variant (OptiDicer) reduced spontaneous choroidal neovascularization in JR5558 mice. Collectively, these findings significantly expand the repertoire of DICER1 in preserving retinal homeostasis by preventing both RPE degeneration and pathological neovascularization.
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Affiliation(s)
- Charles B Wright
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40506
| | - Hironori Uehara
- Department of Ophthalmology, Loma Linda University, Loma Linda, CA 92350
| | - Younghee Kim
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
| | - Tetsuhiro Yasuma
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40506
| | - Reo Yasuma
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
| | - Shuichiro Hirahara
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
| | - Ryan D Makin
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
- Molecular and Cellular Basis of Disease Graduate Program, University of Virginia School of Medicine, Charlottesville, VA 22903
| | - Ivana Apicella
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
| | - Felipe Pereira
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
- Departamento de Oftalmologia e Ciências Visuais, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04039-032, Brazil
| | - Yosuke Nagasaka
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
| | - Siddharth Narendran
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
- Aravind Medical Research Foundation, Aravind Eye Care System, Madurai, Tamil Nadu 625020, India
| | - Shinichi Fukuda
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Tsukuba, Ibaraki 305-8575, Japan
| | - Romulo Albuquerque
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40506
| | - Benjamin J Fowler
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40506
| | - Ana Bastos-Carvalho
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40506
| | - Philippe Georgel
- Laboratoire d'ImmunoRhumatologie Moléculaire, INSERM UMR-S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, 67085 Strasbourg, France
- Fédération Hospitalo-Universitaire OMICARE, Université de Strasbourg, 67085 Strasbourg, France
| | - Izuho Hatada
- Laboratory of Genome Science, Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, ME 04609
| | - Nagaraj Kerur
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
| | | | - Jayakrishna Ambati
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22903
| | - Bradley D Gelfand
- Center for Advanced Vision Science, University of Virginia School of Medicine, Charlottesville, VA 22903;
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22903
- Department of Biomedical Engineering, University of Virginia School of Engineering, Charlottesville, VA 22904
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18
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Petrie JL, Swan C, Ingram RM, Frame FM, Collins AT, Dumay-Odelot H, Teichmann M, Maitland NJ, White RJ. Effects on prostate cancer cells of targeting RNA polymerase III. Nucleic Acids Res 2019; 47:3937-3956. [PMID: 30820548 PMCID: PMC6486637 DOI: 10.1093/nar/gkz128] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/13/2019] [Accepted: 02/19/2019] [Indexed: 12/12/2022] Open
Abstract
RNA polymerase (pol) III occurs in two forms, containing either the POLR3G subunit or the related paralogue POLR3GL. Whereas POLR3GL is ubiquitous, POLR3G is enriched in undifferentiated cells. Depletion of POLR3G selectively triggers proliferative arrest and differentiation of prostate cancer cells, responses not elicited when POLR3GL is depleted. A small molecule pol III inhibitor can cause POLR3G depletion, induce similar differentiation and suppress proliferation and viability of cancer cells. This response involves control of the fate-determining factor NANOG by small RNAs derived from Alu short interspersed nuclear elements. Tumour initiating activity in vivo can be reduced by transient exposure to the pol III inhibitor. Untransformed prostate cells appear less sensitive than cancer cells to pol III depletion or inhibition, raising the possibility of a therapeutic window.
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Affiliation(s)
- John L Petrie
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Caroline Swan
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Richard M Ingram
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Fiona M Frame
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Anne T Collins
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Hélène Dumay-Odelot
- Université de Bordeaux, ARNA Laboratory, F-33076 Bordeaux, France INSERM, U1212 - CNRS UMR 5320, ARNA Laboratory, F-33000 Bordeaux, France
| | - Martin Teichmann
- Université de Bordeaux, ARNA Laboratory, F-33076 Bordeaux, France INSERM, U1212 - CNRS UMR 5320, ARNA Laboratory, F-33000 Bordeaux, France
| | - Norman J Maitland
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Robert J White
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
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19
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RNAase III-Type Enzyme Dicer Regulates Mitochondrial Fatty Acid Oxidative Metabolism in Cardiac Mesenchymal Stem Cells. Int J Mol Sci 2019; 20:ijms20225554. [PMID: 31703292 PMCID: PMC6888515 DOI: 10.3390/ijms20225554] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 11/05/2019] [Indexed: 12/15/2022] Open
Abstract
Cardiac mesenchymal stem cells (C-MSC) play a key role in maintaining normal cardiac function under physiological and pathological conditions. Glycolysis and mitochondrial oxidative phosphorylation predominately account for energy production in C-MSC. Dicer, a ribonuclease III endoribonuclease, plays a critical role in the control of microRNA maturation in C-MSC, but its role in regulating C-MSC energy metabolism is largely unknown. In this study, we found that Dicer knockout led to concurrent increase in both cell proliferation and apoptosis in C-MSC compared to Dicer floxed C-MSC. We analyzed mitochondrial oxidative phosphorylation by quantifying cellular oxygen consumption rate (OCR), and glycolysis by quantifying the extracellular acidification rate (ECAR), in C-MSC with/without Dicer gene deletion. Dicer gene deletion significantly reduced mitochondrial oxidative phosphorylation while increasing glycolysis in C-MSC. Additionally, Dicer gene deletion selectively reduced the expression of β-oxidation genes without affecting the expression of genes involved in the tricarboxylic acid (TCA) cycle or electron transport chain (ETC). Finally, Dicer gene deletion reduced the copy number of mitochondrially encoded 1,4-Dihydronicotinamide adenine dinucleotide (NADH): ubiquinone oxidoreductase core subunit 6 (MT-ND6), a mitochondrial-encoded gene, in C-MSC. In conclusion, Dicer gene deletion induced a metabolic shift from oxidative metabolism to aerobic glycolysis in C-MSC, suggesting that Dicer functions as a metabolic switch in C-MSC, which in turn may regulate proliferation and environmental adaptation.
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20
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Park MS, Araya-Secchi R, Brackbill JA, Phan HD, Kehling AC, Abd El-Wahab EW, Dayeh DM, Sotomayor M, Nakanishi K. Multidomain Convergence of Argonaute during RISC Assembly Correlates with the Formation of Internal Water Clusters. Mol Cell 2019; 75:725-740.e6. [PMID: 31324450 DOI: 10.1016/j.molcel.2019.06.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 04/30/2019] [Accepted: 06/07/2019] [Indexed: 11/17/2022]
Abstract
Despite the relevance of Argonaute proteins in RNA silencing, little is known about the structural steps of small RNA loading to form RNA-induced silencing complexes (RISCs). We report the 1.9 Å crystal structure of human Argonaute4 with guide RNA. Comparison with the previously determined apo structure of Neurospora crassa QDE2 revealed that the PIWI domain has two subdomains. Binding of guide RNA fastens the subdomains, thereby rearranging the active-site residues and increasing the affinity for TNRC6 proteins. We also identified two water pockets beneath the nucleic acid-binding channel that appeared to stabilize the mature RISC. Indeed, mutating the water-pocket residues of Argonaute2 and Argonaute4 compromised RISC assembly. Simulations predict that internal water molecules are exchangeable with the bulk solvent but always occupy specific positions at the domain interfaces. These results suggest that after guide RNA-driven conformational changes, water-mediated hydrogen-bonding networks tie together the converged domains to complete the functional RISC structure.
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Affiliation(s)
- Mi Seul Park
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Raul Araya-Secchi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - James A Brackbill
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Hong-Duc Phan
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA; Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Audrey C Kehling
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ekram W Abd El-Wahab
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel M Dayeh
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA; Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA; Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Kotaro Nakanishi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA; Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.
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21
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Alu RNA Modulates the Expression of Cell Cycle Genes in Human Fibroblasts. Int J Mol Sci 2019; 20:ijms20133315. [PMID: 31284509 PMCID: PMC6651528 DOI: 10.3390/ijms20133315] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 06/27/2019] [Accepted: 07/02/2019] [Indexed: 12/18/2022] Open
Abstract
Alu retroelements, whose retrotransposition requires prior transcription by RNA polymerase III to generate Alu RNAs, represent the most numerous non-coding RNA (ncRNA) gene family in the human genome. Alu transcription is generally kept to extremely low levels by tight epigenetic silencing, but it has been reported to increase under different types of cell perturbation, such as viral infection and cancer. Alu RNAs, being able to act as gene expression modulators, may be directly involved in the mechanisms determining cellular behavior in such perturbed states. To directly address the regulatory potential of Alu RNAs, we generated IMR90 fibroblasts and HeLa cell lines stably overexpressing two slightly different Alu RNAs, and analyzed genome-wide the expression changes of protein-coding genes through RNA-sequencing. Among the genes that were upregulated or downregulated in response to Alu overexpression in IMR90, but not in HeLa cells, we found a highly significant enrichment of pathways involved in cell cycle progression and mitotic entry. Accordingly, Alu overexpression was found to promote transition from G1 to S phase, as revealed by flow cytometry. Therefore, increased Alu RNA may contribute to sustained cell proliferation, which is an important factor of cancer development and progression.
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22
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Guo WT, Wang Y. Dgcr8 knockout approaches to understand microRNA functions in vitro and in vivo. Cell Mol Life Sci 2019; 76:1697-1711. [PMID: 30694346 PMCID: PMC11105204 DOI: 10.1007/s00018-019-03020-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 01/11/2019] [Accepted: 01/17/2019] [Indexed: 01/07/2023]
Abstract
Biologic function of the majority of microRNAs (miRNAs) is still unknown. Uncovering the function of miRNAs is hurdled by redundancy among different miRNAs. The deletion of Dgcr8 leads to the deficiency in producing all canonical miRNAs, therefore, overcoming the redundancy issue. Dgcr8 knockout strategy has been instrumental in understanding the function of miRNAs in a variety of cells in vitro and in vivo. In this review, we will first give a brief introduction about miRNAs, miRNA biogenesis pathway and the role of Dgcr8 in miRNA biogenesis. We will then summarize studies performed with Dgcr8 knockout cell models with a focus on embryonic stem cells. After that, we will summarize results from various in vivo Dgcr8 knockout models. Given significant phenotypic differences in various tissues between Dgcr8 and Dicer knockout, we will also briefly review current progresses on understanding miRNA-independent functions of miRNA biogenesis factors. Finally, we will discuss the potential use of a new strategy to stably express miRNAs in Dgcr8 knockout cells. In future, Dgcr8 knockout approaches coupled with innovations in miRNA rescue strategy may provide further insights into miRNA functions in vitro and in vivo.
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Affiliation(s)
- Wen-Ting Guo
- Central Laboratory, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, No. 1 Shuaifuyuan, Beijing, 100730, People's Republic of China
| | - Yangming Wang
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, People's Republic of China.
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23
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Exaptation at the molecular genetic level. SCIENCE CHINA-LIFE SCIENCES 2018; 62:437-452. [PMID: 30798493 DOI: 10.1007/s11427-018-9447-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 12/01/2018] [Indexed: 12/22/2022]
Abstract
The realization that body parts of animals and plants can be recruited or coopted for novel functions dates back to, or even predates the observations of Darwin. S.J. Gould and E.S. Vrba recognized a mode of evolution of characters that differs from adaptation. The umbrella term aptation was supplemented with the concept of exaptation. Unlike adaptations, which are restricted to features built by selection for their current role, exaptations are features that currently enhance fitness, even though their present role was not a result of natural selection. Exaptations can also arise from nonaptations; these are characters which had previously been evolving neutrally. All nonaptations are potential exaptations. The concept of exaptation was expanded to the molecular genetic level which aided greatly in understanding the enormous potential of neutrally evolving repetitive DNA-including transposed elements, formerly considered junk DNA-for the evolution of genes and genomes. The distinction between adaptations and exaptations is outlined in this review and examples are given. Also elaborated on is the fact that such distinctions are sometimes more difficult to determine; this is a widespread phenomenon in biology, where continua abound and clear borders between states and definitions are rare.
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24
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De Cauwer A, Mariotte A, Sibilia J, Bahram S, Georgel P. DICER1: A Key Player in Rheumatoid Arthritis, at the Crossroads of Cellular Stress, Innate Immunity, and Chronic Inflammation in Aging. Front Immunol 2018; 9:1647. [PMID: 30087677 PMCID: PMC6066587 DOI: 10.3389/fimmu.2018.01647] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 07/04/2018] [Indexed: 12/20/2022] Open
Abstract
Loss-of-function or knockout mouse models have established a fundamental role for the RNAse III enzyme DICER1 in development and tissue morphogenesis and/or homeostasis. These functions are currently assumed to result mainly from the DICER1-dependent biogenesis of microRNAs which exhibit important gene expression regulatory properties. However, non-canonical DICER1 functions have recently emerged. These include interaction with the DNA damage response (DDR) pathway and the processing of cytotoxic non-coding RNAs, suggesting that DICER1 might also participate in the regulation of major cellular processes through miRNA-independent mechanisms. Recent findings indicated that reduced Dicer1 expression, which correlates with worsened symptoms in mouse models of joint inflammation, is also noted in fibroblast-like synoviocytes (FLS) harvested from rheumatoid arthritis (RA) patients, as opposed to FLS cultured from biopsies of osteoarthritic patients. In addition, low DICER1 levels are associated with the establishment of cellular stress and its associated responses, such as cellular senescence. Senescent and/or stressed cells are associated with an inflammatory secretome (cytokines and chemokines), as well as with "find-me" and "eat-me" signals which will attract and activate the innate immune compartment (NK cells, macrophages, and neutrophils) to be eliminated. Failure of this immunosurveillance mechanism and improper restauration of homeostasis could lead to the establishment of a systemic and chronic inflammatory state. In this review, we suggest that reduced DICER1 expression contributes to a vicious cycle during which accumulating inflammation and premature senescence, combined to inadequate innate immunity responses, creates the appropriate conditions for the initiation and/or progression of autoimmune-autoinflammatory diseases, such as RA.
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Affiliation(s)
- Aurore De Cauwer
- Université de Strasbourg, INSERM, ImmunoRhumatologie Moléculaire UMR_S 1109, Fédération de Médecine Translationnelle de Strasbourg, Faculté de Médecine, Strasbourg, France.,Fédération Hospitalo-Universitaire, OMICARE, Centre de Recherche d'Immunologie et d'Hématologie, Strasbourg, France
| | - Alexandre Mariotte
- Université de Strasbourg, INSERM, ImmunoRhumatologie Moléculaire UMR_S 1109, Fédération de Médecine Translationnelle de Strasbourg, Faculté de Médecine, Strasbourg, France.,Fédération Hospitalo-Universitaire, OMICARE, Centre de Recherche d'Immunologie et d'Hématologie, Strasbourg, France
| | - Jean Sibilia
- Université de Strasbourg, INSERM, ImmunoRhumatologie Moléculaire UMR_S 1109, Fédération de Médecine Translationnelle de Strasbourg, Faculté de Médecine, Strasbourg, France.,Fédération Hospitalo-Universitaire, OMICARE, Centre de Recherche d'Immunologie et d'Hématologie, Strasbourg, France.,Centre de Référence des Maladies Autoimmunes Rares, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Seiamak Bahram
- Université de Strasbourg, INSERM, ImmunoRhumatologie Moléculaire UMR_S 1109, Fédération de Médecine Translationnelle de Strasbourg, Faculté de Médecine, Strasbourg, France.,Fédération Hospitalo-Universitaire, OMICARE, Centre de Recherche d'Immunologie et d'Hématologie, Strasbourg, France
| | - Philippe Georgel
- Université de Strasbourg, INSERM, ImmunoRhumatologie Moléculaire UMR_S 1109, Fédération de Médecine Translationnelle de Strasbourg, Faculté de Médecine, Strasbourg, France.,Fédération Hospitalo-Universitaire, OMICARE, Centre de Recherche d'Immunologie et d'Hématologie, Strasbourg, France
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25
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The role of Alu-derived RNAs in Alzheimer's and other neurodegenerative conditions. Med Hypotheses 2018; 115:29-34. [PMID: 29685192 DOI: 10.1016/j.mehy.2018.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/16/2018] [Accepted: 03/20/2018] [Indexed: 12/14/2022]
Abstract
Non-coding RNAs have emerged as essential contributors to neuroinflammation. The Alu element is the most abundant potential source of non-coding RNA in the human genome represented by over 1.1 million copies totaling ∼10% of the genome's mass. Accumulation of "Alu RNA" was observed in the brains of individuals with dementia and Creutzfeldt-Jakob disease - a degenerative brain disorder. "Alu RNAs" activate inflammatory pathways and apoptosis in the non-neural cells. In particular, the "Alu RNA" cytotoxicity is suggested as a mechanism in retinal pigment epithelium (RPE), a compartment damaged in the process of age-related macular degeneration. In RPE cells, the deficiency of Dicer is reported to lead to an accumulation of P3Alu transcripts, subsequent activation of the ERK1/2 signaling pathway, and the formation of NLRP3 inflammasome. In turn, these events result in RPE cell death by apoptosis. Importantly, RPE cells are of neuroectodermal origin, these cells display more similarity to neurons than to other epithelial cells. Thus, it is plausible that the mechanisms of "Alu RNA" cytotoxicity in brain neurons are similar to that in RPE. We hypothesize that accumulation of polymerase III-transcribed noncoding RNA of Alu (P3Alu) may contribute to both neuroinflammation and neurodegeneration associated with Alzheimer's disease (AD) and other degenerative brain disorders. This hypothesis points toward a novel molecular pathway not previously considered for the treatment of AD.
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26
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Tristán-Flores FE, Guzmán P, Ortega-Kermedy MS, Cruz-Torres G, de la Rocha C, Silva-Martínez GA, Rodríguez-Ríos D, Alvarado-Caudillo Y, Barbosa-Sabanero G, Sayols S, Lund G, Zaina S. Liver X Receptor-Binding DNA Motif Associated With Atherosclerosis-Specific DNA Methylation Profiles of Alu Elements and Neighboring CpG Islands. J Am Heart Assoc 2018; 7:e007686. [PMID: 29386205 PMCID: PMC5850253 DOI: 10.1161/jaha.117.007686] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 10/18/2017] [Indexed: 12/21/2022]
Abstract
BACKGROUND The signals that determine atherosclerosis-specific DNA methylation profiles are only partially known. We previously identified a 29-bp DNA motif (differential methylation motif [DMM]) proximal to CpG islands (CGIs) that undergo demethylation in advanced human atheromas. Those data hinted that the DMM docks modifiers of DNA methylation and transcription. METHODS AND RESULTS We sought to functionally characterize the DMM. We showed that the DMM overlaps with the RNA polymerase III-binding B box of Alu short interspersed nuclear elements and contains a DR2 nuclear receptor response element. Pointing to a possible functional role for an Alu DMM, CGIs proximal (<100 bp) to near-intact DMM-harboring Alu are significantly less methylated relative to CGIs proximal to degenerate DMM-harboring Alu or to DMM-devoid mammalian-wide interspersed repeat short interspersed nuclear elements in human arteries. As for DMM-binding factors, LXRB (liver X receptor β) binds the DMM in a DR2-dependent fashion, and LXR (liver X receptor) agonists induce significant hypermethylation of the bulk of Alu in THP-1 cells. Furthermore, we describe 3 intergenic long noncoding RNAs that harbor a DMM, are under transcriptional control by LXR agonists, and are differentially expressed between normal and atherosclerotic human aortas. Notably, CGIs adjacent to those long noncoding RNAs tend to be hypomethylated in symptomatic relative to stable human atheromas. CONCLUSIONS Collectively, the data suggest that a DMM is associated with 2 distinct methylation states: relatively low methylation of in cis CGIs and Alu element hypermethylation. Based on the known atheroprotective role of LXRs, we propose that LXR agonist-induced Alu hypermethylation, a landmark of atherosclerosis, is a compensatory rather than proatherogenic response.
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Affiliation(s)
| | - Plinio Guzmán
- Department of Genetic Engineering, CINVESTAV Irapuato Unit, Irapuato, Gto, Mexico
| | | | - Gabriela Cruz-Torres
- Department of Medical Sciences, Division of Health Sciences, León Campus, University of Guanajuato, León, Gto, Mexico
| | - Carmen de la Rocha
- Department of Genetic Engineering, CINVESTAV Irapuato Unit, Irapuato, Gto, Mexico
| | | | - Dalia Rodríguez-Ríos
- Department of Genetic Engineering, CINVESTAV Irapuato Unit, Irapuato, Gto, Mexico
| | - Yolanda Alvarado-Caudillo
- Department of Medical Sciences, Division of Health Sciences, León Campus, University of Guanajuato, León, Gto, Mexico
| | - Gloria Barbosa-Sabanero
- Department of Medical Sciences, Division of Health Sciences, León Campus, University of Guanajuato, León, Gto, Mexico
| | - Sergi Sayols
- Institute of Molecular Biology gGmbH, Mainz, Germany
| | - Gertrud Lund
- Department of Genetic Engineering, CINVESTAV Irapuato Unit, Irapuato, Gto, Mexico
| | - Silvio Zaina
- Department of Medical Sciences, Division of Health Sciences, León Campus, University of Guanajuato, León, Gto, Mexico
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27
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Hu Q, Khanna P, Ee Wong BS, Lin Heng ZS, Subhramanyam CS, Thanga LZ, Sing Tan SW, Baeg GH. Oxidative stress promotes exit from the stem cell state and spontaneous neuronal differentiation. Oncotarget 2017; 9:4223-4238. [PMID: 29423117 PMCID: PMC5790534 DOI: 10.18632/oncotarget.23786] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/27/2017] [Indexed: 12/12/2022] Open
Abstract
Reactive oxygen species (ROS) play important roles in fundamental cellular processes such as proliferation and survival. Here we investigated the effect of oxidative stress on stem cell maintenance and neuronal differentiation in a human embryonic stem cell (hESC) model, Ntera2 (NT2). CM-H2DCFDA and DHE assays confirmed that the oxidizing agent paraquat could induce a high level of ROS in NT2 cells. Quantitative PCR, Western blotting and immunocytochemistry showed that paraquat-induced oxidative stress suppressed the expression of stemness markers, including NANOG, OCT4 and TDGF1, whereas it enhanced the spontaneous expression of neuronal differentiation markers such as PAX6, NEUROD1, HOXA1, NCAM, GFRA1 and TUJ1. The treated cells even exhibited a strikingly different morphology from control cells, extending out long neurite-like processes. The neurogenic effect of ROS on stem cell behaviour was confirmed by the observations that the expression of neuronal markers in the paraquat-treated cells was suppressed by an antioxidant while further enhanced by knocking down Nrf2, a key transcription factor associated with antioxidant signaling. Lastly, paraquat dose-dependently activated the neurogenic MAPK-ERK1/2, which can be reversed by the MEK1/2 inhibitor SL327. Our study suggests that excessive intracellular ROS can trigger the exit from stem cell state and promote the neuronal differentiation of hESCs, and that MAPK-ERK1/2 signaling may play a proactive role in the ROS-induced neuronal differentiation of hESCs.
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Affiliation(s)
- Qidong Hu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, MD 10, Singapore
| | - Puja Khanna
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, MD 10, Singapore
| | - Belinda Shu Ee Wong
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, MD 10, Singapore
| | - Zealyn Shi Lin Heng
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, MD 10, Singapore
| | | | - Lal Zo Thanga
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, MD 10, Singapore
| | - Sharon Wui Sing Tan
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, MD 10, Singapore
| | - Gyeong Hun Baeg
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, MD 10, Singapore
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28
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Karijolich J, Zhao Y, Alla R, Glaunsinger B. Genome-wide mapping of infection-induced SINE RNAs reveals a role in selective mRNA export. Nucleic Acids Res 2017; 45:6194-6208. [PMID: 28334904 PMCID: PMC5449642 DOI: 10.1093/nar/gkx180] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 03/08/2017] [Indexed: 12/11/2022] Open
Abstract
Short interspersed nuclear elements (SINEs) are retrotransposons evolutionarily derived from endogenous RNA Polymerase III RNAs. Though SINE elements have undergone exaptation into gene regulatory elements, how transcribed SINE RNA impacts transcriptional and post-transcriptional regulation is largely unknown. This is partly due to a lack of information regarding which of the loci have transcriptional potential. Here, we present an approach (short interspersed nuclear element sequencing, SINE-seq), which selectively profiles RNA Polymerase III-derived SINE RNA, thereby identifying transcriptionally active SINE loci. Applying SINE-seq to monitor murine B2 SINE expression during a gammaherpesvirus infection revealed transcription from 28 270 SINE loci, with ∼50% of active SINE elements residing within annotated RNA Polymerase II loci. Furthermore, B2 RNA can form intermolecular RNA–RNA interactions with complementary mRNAs, leading to nuclear retention of the targeted mRNA via a mechanism involving p54nrb. These findings illuminate a pathway for the selective regulation of mRNA export during stress via retrotransposon activation.
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Affiliation(s)
- John Karijolich
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3370, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3370, USA.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232-2363, USA
| | - Yang Zhao
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232-2363, USA
| | - Ravi Alla
- California Institute for Quantitative Biology, University of California, Berkeley, CA 94720-3370, USA
| | - Britt Glaunsinger
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3370, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3370, USA.,California Institute for Quantitative Biology, University of California, Berkeley, CA 94720-3370, USA
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29
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Linker SB, Marchetto MC, Narvaiza I, Denli AM, Gage FH. Examining non-LTR retrotransposons in the context of the evolving primate brain. BMC Biol 2017; 15:68. [PMID: 28800766 PMCID: PMC5554003 DOI: 10.1186/s12915-017-0409-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Researchers have long sought to understand the genetic basis of the cognitive differences between primates, with particular focus on the human brain. Although all mutational types have worked in concert with evolutionary forces to generate the current human brain, in this review we will explore the impact of mobile elements, specifically non-LTR retrotransposons. Non-LTR retrotransposons have contributed coding and regulatory sequences to the genome throughout evolution. During primate evolution there have been multiple waves of LINE retrotransposition as well as the birth of new mobile elements such as the SINEs Alu and SVA and we will explore what kinds of impacts these may have had on the evolving human brain.
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Affiliation(s)
- Sara B Linker
- Salk Institute for Biological Studies, La Jolla, CA, 92037-1002, USA
| | - Maria C Marchetto
- Salk Institute for Biological Studies, La Jolla, CA, 92037-1002, USA
| | - Iñigo Narvaiza
- Salk Institute for Biological Studies, La Jolla, CA, 92037-1002, USA
| | - Ahmet M Denli
- Salk Institute for Biological Studies, La Jolla, CA, 92037-1002, USA
| | - Fred H Gage
- Salk Institute for Biological Studies, La Jolla, CA, 92037-1002, USA.
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30
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Molecular mechanisms of Dicer: endonuclease and enzymatic activity. Biochem J 2017; 474:1603-1618. [PMID: 28473628 PMCID: PMC5415849 DOI: 10.1042/bcj20160759] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 12/12/2022]
Abstract
The enzyme Dicer is best known for its role as a riboendonuclease in the small RNA pathway. In this canonical role, Dicer is a critical regulator of the biogenesis of microRNA and small interfering RNA, as well as a growing number of additional small RNAs derived from various sources. Emerging evidence demonstrates that Dicer's endonuclease role extends beyond the generation of small RNAs; it is also involved in processing additional endogenous and exogenous substrates, and is becoming increasingly implicated in regulating a variety of other cellular processes, outside of its endonuclease function. This review will describe the canonical and newly identified functions of Dicer.
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31
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Burke JM, Sullivan CS. DUSP11 - An RNA phosphatase that regulates host and viral non-coding RNAs in mammalian cells. RNA Biol 2017; 14:1457-1465. [PMID: 28296624 PMCID: PMC5785229 DOI: 10.1080/15476286.2017.1306169] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dual-specificity phosphatase 11 (DUSP11) is a conserved protein tyrosine phosphatase (PTP) in metazoans. The cellular substrates and physiologic activities of DUSP11 remain largely unknown. In nematodes, DUSP11 is required for normal development and RNA interference against endogenous RNAs (endo-RNAi) via molecular mechanisms that are not well understood. However, mammals lack analogous endo-RNAi pathways and consequently, a role for DUSP11 in mammalian RNA silencing was unanticipated. Recent work from our laboratory demonstrated that DUSP11 activity alters the silencing potential of noncanonical viral miRNAs in mammalian cells. Our studies further uncovered direct cellular substrates of DUSP11 and suggest that DUSP11 is part of regulatory pathway that controls the abundance of select triphosphorylated noncoding RNAs. Here, we highlight recent findings and present new data that advance understanding of mammalian DUSP11 during gene silencing and discuss the emerging biological activities of DUSP11 in mammalian cells.
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Affiliation(s)
- James M Burke
- a The University of Texas at Austin , Center for Systems and Synthetic Biology, Center for Infectious Disease and Department of Molecular Biosciences , Austin , TX , USA
| | - Christopher S Sullivan
- a The University of Texas at Austin , Center for Systems and Synthetic Biology, Center for Infectious Disease and Department of Molecular Biosciences , Austin , TX , USA
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32
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RNY (YRNA)-derived small RNAs regulate cell death and inflammation in monocytes/macrophages. Cell Death Dis 2017; 8:e2530. [PMID: 28055017 PMCID: PMC5386355 DOI: 10.1038/cddis.2016.429] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 11/15/2016] [Accepted: 11/15/2016] [Indexed: 01/01/2023]
Abstract
The recent discovery of new classes of small RNAs has opened unknown territories to explore new regulations of physiopathological events. We have recently demonstrated that RNY (or Y RNA)-derived small RNAs (referred to as s-RNYs) are an independent class of clinical biomarkers to detect coronary artery lesions and are associated with atherosclerosis burden. Here, we have studied the role of s-RNYs in human and mouse monocytes/macrophages and have shown that in lipid-laden monocytes/macrophages s-RNY expression is timely correlated to the activation of both NF-κB and caspase 3-dependent cell death pathways. Loss- or gain-of-function experiments demonstrated that s-RNYs activate caspase 3 and NF-κB signaling pathways ultimately promoting cell death and inflammatory responses. As, in atherosclerosis, Ro60-associated s-RNYs generated by apoptotic macrophages are released in the blood of patients, we have investigated the extracellular function of the s-RNY/Ro60 complex. Our data demonstrated that s-RNY/Ro60 complex induces caspase 3-dependent cell death and NF-κB-dependent inflammation, when added to the medium of cultured monocytes/macrophages. Finally, we have shown that s-RNY function is mediated by Toll-like receptor 7 (TLR7). Indeed using chloroquine, which disrupts signaling of endosome-localized TLRs 3, 7, 8 and 9 or the more specific TLR7/9 antagonist, the phosphorothioated oligonucleotide IRS954, we blocked the effect of either intracellular or extracellular s-RNYs. These results position s-RNYs as relevant novel functional molecules that impacts on macrophage physiopathology, indicating their potential role as mediators of inflammatory diseases, such as atherosclerosis.
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33
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Abstract
Retrotransposons have generated about 40 % of the human genome. This review examines the strategies the cell has evolved to coexist with these genomic "parasites", focussing on the non-long terminal repeat retrotransposons of humans and mice. Some of the restriction factors for retrotransposition, including the APOBECs, MOV10, RNASEL, SAMHD1, TREX1, and ZAP, also limit replication of retroviruses, including HIV, and are part of the intrinsic immune system of the cell. Many of these proteins act in the cytoplasm to degrade retroelement RNA or inhibit its translation. Some factors act in the nucleus and involve DNA repair enzymes or epigenetic processes of DNA methylation and histone modification. RISC and piRNA pathway proteins protect the germline. Retrotransposon control is relaxed in some cell types, such as neurons in the brain, stem cells, and in certain types of disease and cancer, with implications for human health and disease. This review also considers potential pitfalls in interpreting retrotransposon-related data, as well as issues to consider for future research.
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Affiliation(s)
- John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA 212051
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34
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Kalantari R, Hicks JA, Li L, Gagnon KT, Sridhara V, Lemoff A, Mirzaei H, Corey DR. Stable association of RNAi machinery is conserved between the cytoplasm and nucleus of human cells. RNA (NEW YORK, N.Y.) 2016; 22:1085-98. [PMID: 27198507 PMCID: PMC4911916 DOI: 10.1261/rna.056499.116] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/25/2016] [Indexed: 05/25/2023]
Abstract
Argonaute 2 (AGO2), the catalytic engine of RNAi, is typically associated with inhibition of translation in the cytoplasm. AGO2 has also been implicated in nuclear processes including transcription and splicing. There has been little insight into AGO2's nuclear interactions or how they might differ relative to cytoplasm. Here we investigate the interactions of cytoplasmic and nuclear AGO2 using semi-quantitative mass spectrometry. Mass spectrometry often reveals long lists of candidate proteins, complicating efforts to rigorously discriminate true interacting partners from artifacts. We prioritized candidates using orthogonal analytical strategies that compare replicate mass spectra of proteins associated with Flag-tagged and endogenous AGO2. Interactions with TRNC6A, TRNC6B, TNRC6C, and AGO3 are conserved between nuclei and cytoplasm. TAR binding protein interacted stably with cytoplasmic AGO2 but not nuclear AGO2, consistent with strand loading in the cytoplasm. Our data suggest that interactions between functionally important components of RNAi machinery are conserved between the nucleus and cytoplasm but that accessory proteins differ. Orthogonal analysis of mass spectra is a powerful approach to streamlining identification of protein partners.
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Affiliation(s)
- Roya Kalantari
- Department of Pharmacology, Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Jessica A Hicks
- Department of Pharmacology, Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Liande Li
- Department of Pharmacology, Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Keith T Gagnon
- Department of Biochemistry and Molecular Biology, Southern Illinois University, Carbondale, Illinois 62901, USA
| | - Viswanadham Sridhara
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Andrew Lemoff
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Hamid Mirzaei
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - David R Corey
- Department of Pharmacology, Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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Intracellular and extracellular microRNA: An update on localization and biological role. ACTA ACUST UNITED AC 2016; 51:33-49. [PMID: 27396686 DOI: 10.1016/j.proghi.2016.06.001] [Citation(s) in RCA: 153] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/24/2016] [Accepted: 06/24/2016] [Indexed: 12/12/2022]
Abstract
MicroRNA (miRNA) is a class of small non-coding RNAs which mediate post-transcriptional gene silencing (PTGS) by sequence-specific inhibition of target mRNAs translation and/or lowering their half-lives in the cytoplasm. Together with their binding partners, Argonaute (AGO) proteins, miRNAs form cores of RNA-induced silencing complexes (RISC). Despite a substantial progress in understanding RISC structure, until recently little was known about its localization in the cell. This review is aimed to provide an overview of the emerging picture of miRNA and RISC localization and function both in the intracellular space and outside of the cell. In contrast to the common assumption that PTGS occurs in the cytoplasm, it was found to operate mainly on the membranes of the endoplasmic reticulum (ER). Besides ER membranes miRNAs were found in all main cellular compartments including nucleus, nucleolus and mitochondria where they regulate various processes including transcription, translation, alternative splicing and DNA repair. Moreover, a certain pool of miRNAs may not be associated with RISC and carry completely different functions. Finally, the discovery of cell-free miRNAs in all biological fluids suggests that miRNAs might also act as signaling molecules outside the cell, and may be utilized as biomarkers for a variety of diseases. In this review we discuss miRNA secretion mechanisms and possible pathways of cell-cell communication via miRNA-containing exosomes in vivo.
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Morales-Hernández A, González-Rico FJ, Román AC, Rico-Leo E, Alvarez-Barrientos A, Sánchez L, Macia Á, Heras SR, García-Pérez JL, Merino JM, Fernández-Salguero PM. Alu retrotransposons promote differentiation of human carcinoma cells through the aryl hydrocarbon receptor. Nucleic Acids Res 2016; 44:4665-83. [PMID: 26883630 PMCID: PMC4889919 DOI: 10.1093/nar/gkw095] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/09/2016] [Indexed: 12/18/2022] Open
Abstract
Cell differentiation is a central process in development and in cancer growth and dissemination. OCT4 (POU5F1) and NANOG are essential for cell stemness and pluripotency; yet, the mechanisms that regulate their expression remain largely unknown. Repetitive elements account for almost half of the Human Genome; still, their role in gene regulation is poorly understood. Here, we show that the dioxin receptor (AHR) leads to differentiation of human carcinoma cells through the transcriptional upregulation of Alu retrotransposons, whose RNA transcripts can repress pluripotency genes. Despite the genome-wide presence of Alu elements, we provide evidences that those located at the NANOG and OCT4 promoters bind AHR, are transcribed by RNA polymerase-III and repress NANOG and OCT4 in differentiated cells. OCT4 and NANOG repression likely involves processing of Alu-derived transcripts through the miRNA machinery involving the Microprocessor and RISC. Consistently, stable AHR knockdown led to basal undifferentiation, impaired Alus transcription and blockade of OCT4 and NANOG repression. We suggest that transcripts produced from AHR-regulated Alu retrotransposons may control the expression of stemness genes OCT4 and NANOG during differentiation of carcinoma cells. The control of discrete Alu elements by specific transcription factors may have a dynamic role in genome regulation under physiological and diseased conditions.
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Affiliation(s)
- Antonio Morales-Hernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Francisco J González-Rico
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Angel C Román
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avenida Doctor Arce 37, 28002-Madrid, Spain
| | - Eva Rico-Leo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Alberto Alvarez-Barrientos
- Servicio de Técnicas Aplicadas a las Biociencias, Universidad de Extremadura, Avenida de Elvas s/n 06071-Badajoz, Spain
| | - Laura Sánchez
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Ángela Macia
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Sara R Heras
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - José L García-Pérez
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Jaime M Merino
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Pedro M Fernández-Salguero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
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Marçola M, Lopes-Ramos CM, Pereira EP, Cecon E, Fernandes PA, Tamura EK, Camargo AA, Parmigiani RB, Markus RP. Light/Dark Environmental Cycle Imposes a Daily Profile in the Expression of microRNAs in Rat CD133+Cells. J Cell Physiol 2016; 231:1953-63. [DOI: 10.1002/jcp.25300] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/04/2016] [Indexed: 02/07/2023]
Affiliation(s)
- Marina Marçola
- Department of Physiology; Laboratory of Chronopharmacology; Institute of Bioscience; University of São Paulo; São Paulo City São Paulo Brazil
| | - Camila M. Lopes-Ramos
- Centro de Oncologia Molecular; Hospital Sírio-Libanês; São Paulo City São Paulo Brazil
| | - Eliana P. Pereira
- Department of Physiology; Laboratory of Chronopharmacology; Institute of Bioscience; University of São Paulo; São Paulo City São Paulo Brazil
| | - Erika Cecon
- Department of Physiology; Laboratory of Chronopharmacology; Institute of Bioscience; University of São Paulo; São Paulo City São Paulo Brazil
| | - Pedro A. Fernandes
- Department of Physiology; Laboratory of Chronopharmacology; Institute of Bioscience; University of São Paulo; São Paulo City São Paulo Brazil
| | - Eduardo K. Tamura
- Department of Physiology; Laboratory of Chronopharmacology; Institute of Bioscience; University of São Paulo; São Paulo City São Paulo Brazil
| | - Anamaria A. Camargo
- Centro de Oncologia Molecular; Hospital Sírio-Libanês; São Paulo City São Paulo Brazil
| | - Raphael B. Parmigiani
- Centro de Oncologia Molecular; Hospital Sírio-Libanês; São Paulo City São Paulo Brazil
| | - Regina P. Markus
- Department of Physiology; Laboratory of Chronopharmacology; Institute of Bioscience; University of São Paulo; São Paulo City São Paulo Brazil
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Karijolich J, Abernathy E, Glaunsinger BA. Infection-Induced Retrotransposon-Derived Noncoding RNAs Enhance Herpesviral Gene Expression via the NF-κB Pathway. PLoS Pathog 2015; 11:e1005260. [PMID: 26584434 PMCID: PMC4652899 DOI: 10.1371/journal.ppat.1005260] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/13/2015] [Indexed: 02/07/2023] Open
Abstract
Short interspersed nuclear elements (SINEs) are highly abundant, RNA polymerase III-transcribed noncoding retrotransposons that are silenced in somatic cells but activated during certain stresses including viral infection. How these induced SINE RNAs impact the host-pathogen interaction is unknown. Here we reveal that during murine gammaherpesvirus 68 (MHV68) infection, rapidly induced SINE RNAs activate the antiviral NF-κB signaling pathway through both mitochondrial antiviral-signaling protein (MAVS)-dependent and independent mechanisms. However, SINE RNA-based signaling is hijacked by the virus to enhance viral gene expression and replication. B2 RNA expression stimulates IKKβ-dependent phosphorylation of the major viral lytic cycle transactivator protein RTA, thereby enhancing its activity and increasing progeny virion production. Collectively, these findings suggest that SINE RNAs participate in the innate pathogen response mechanism, but that herpesviruses have evolved to co-opt retrotransposon activation for viral benefit. Short interspersed nuclear elements (SINEs) are noncoding mobile genetic elements that are present at ~106 copies per mammalian genome, roughly comprising 10% of mammalian genomic real estate. SINEs are typically transcriptionally silenced, though in some cases viral infection can promote their expression, yet to an unknown functional outcome. Thus, SINE elements represent the largest class of infection-inducible noncoding RNAs that are functionally uncharacterized. Here, we reveal that SINE RNAs play a critical role in the host-pathogen interaction in that they are required for efficient murine gammaherpesvirus 68 (MHV68) replication and gene expression. We demonstrate that SINE RNAs, both exogenously expressed and infection-induced, are robust activators of the IKKβ kinase, a key signaling molecule in the innate immune response. Activation of the IKKβ kinase by SINE RNA is mediated through both MAVS-dependent and independent mechanisms. Moreover, we demonstrate the activation of the IKKβ via SINE RNA is required to drive the phosphorylation of MHV68 RTA, the main viral transcriptional activator, which enhances its transcriptional activating property. Collectively, we reveal the first example of a role for SINE RNAs in the host-pathogen interaction and identify them as a key immune signaling molecule early during infection. Though SINE RNAs activate the innate immune response, MHV68 has co-opted SINE-mediate innate immune activation to enhance the viral lifecycle.
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Affiliation(s)
- John Karijolich
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Emma Abernathy
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Britt A. Glaunsinger
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, United States of America
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California, United States of America
- * E-mail:
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39
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Iwakawa HO, Tomari Y. The Functions of MicroRNAs: mRNA Decay and Translational Repression. Trends Cell Biol 2015; 25:651-665. [PMID: 26437588 DOI: 10.1016/j.tcb.2015.07.011] [Citation(s) in RCA: 533] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 07/27/2015] [Accepted: 07/29/2015] [Indexed: 12/14/2022]
Abstract
MicroRNAs (miRNAs) are a class of endogenous small noncoding RNAs, which regulate complementary mRNAs by inducing translational repression and mRNA decay. Although this dual repression system seems to operate in both animals and plants, genetic and biochemical studies suggest that the mechanism underlying the miRNA-mediated silencing is different in the two kingdoms. Here, we review the recent progress in our understanding of how miRNAs mediate translational repression and mRNA decay, and discuss the contributions of the two silencing modes to the overall silencing effect in both kingdoms.
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Affiliation(s)
- Hiro-Oki Iwakawa
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Yukihide Tomari
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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40
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Sundermeier TR, Palczewski K. The impact of microRNA gene regulation on the survival and function of mature cell types in the eye. FASEB J 2015; 30:23-33. [PMID: 26399786 DOI: 10.1096/fj.15-279745] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/14/2015] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) regulate multiple genes, often within the same pathway, fine-tuning expression of key factors and stabilizing gene networks against aberrant fluctuations. The demanding physiologic functions of photoreceptor cells and the retinal pigmented epithelium necessitate precise gene regulation to maintain their homeostasis and function, thus rendering these postmitotic cells vulnerable to premature death in retinal degenerative disorders. Recent studies of the physiologic impact of miRNAs in these cells clearly demonstrate that miRNAs are an essential component of that gene regulation. These important advances provide the foundation for future exploration of miRNA-regulated gene networks in the eye to facilitate the development of miRNA-targeted therapeutics to combat blinding diseases.
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Affiliation(s)
- Thomas R Sundermeier
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio, USA
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41
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Argonaute 2 Binds Directly to tRNA Genes and Promotes Gene Repression in cis. Mol Cell Biol 2015; 35:2278-94. [PMID: 25918241 DOI: 10.1128/mcb.00076-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To further our understanding of the RNAi machinery within the human nucleus, we analyzed the chromatin and RNA binding of Argonaute 2 (AGO2) within human cancer cell lines. Our data indicated that AGO2 binds directly to nascent tRNA and 5S rRNA, and to the genomic loci from which these RNAs are transcribed, in a small RNA- and DICER-independent manner. AGO2 chromatin binding was not observed at non-TFIIIC-dependent RNA polymerase III (Pol III) genes or at extra-TFIIIC (ETC) sites, indicating that the interaction is specific for TFIIIC-dependent Pol III genes. A genome-wide analysis indicated that loss of AGO2 caused a global increase in mRNA expression level among genes that flank AGO2-bound tRNA genes. This effect was shown to be distinct from that of the disruption of DICER, DROSHA, or CTCF. We propose that AGO2 binding to tRNA genes has a novel and important regulatory role in human cells.
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42
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Gelfand BD, Wright CB, Kim Y, Yasuma T, Yasuma R, Li S, Fowler BJ, Bastos-Carvalho A, Kerur N, Uittenbogaard A, Han YS, Lou D, Kleinman ME, McDonald WH, Núñez G, Georgel P, Dunaief JL, Ambati J. Iron Toxicity in the Retina Requires Alu RNA and the NLRP3 Inflammasome. Cell Rep 2015; 11:1686-93. [PMID: 26074074 DOI: 10.1016/j.celrep.2015.05.023] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/23/2015] [Accepted: 05/08/2015] [Indexed: 12/16/2022] Open
Abstract
Excess iron induces tissue damage and is implicated in age-related macular degeneration (AMD). Iron toxicity is widely attributed to hydroxyl radical formation through Fenton's reaction. We report that excess iron, but not other Fenton catalytic metals, induces activation of the NLRP3 inflammasome, a pathway also implicated in AMD. Additionally, iron-induced degeneration of the retinal pigmented epithelium (RPE) is suppressed in mice lacking inflammasome components caspase-1/11 or Nlrp3 or by inhibition of caspase-1. Iron overload increases abundance of RNAs transcribed from short interspersed nuclear elements (SINEs): Alu RNAs and the rodent equivalent B1 and B2 RNAs, which are inflammasome agonists. Targeting Alu or B2 RNA prevents iron-induced inflammasome activation and RPE degeneration. Iron-induced SINE RNA accumulation is due to suppression of DICER1 via sequestration of the co-factor poly(C)-binding protein 2 (PCBP2). These findings reveal an unexpected mechanism of iron toxicity, with implications for AMD and neurodegenerative diseases associated with excess iron.
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Affiliation(s)
- Bradley D Gelfand
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA; Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40536, USA; Department of Microbiology, Immunology, and Human Genetics, University of Kentucky, Lexington, KY 40536, USA.
| | - Charles B Wright
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Younghee Kim
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Tetsuhiro Yasuma
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Reo Yasuma
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Shengjian Li
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Benjamin J Fowler
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA; Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
| | - Ana Bastos-Carvalho
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Nagaraj Kerur
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Annette Uittenbogaard
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Youn Seon Han
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Dingyuan Lou
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Mark E Kleinman
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - W Hayes McDonald
- Proteomics Laboratory, Mass Spectrometry Research Center and Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37205, USA
| | - Gabriel Núñez
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Philippe Georgel
- INSERM UMR_S 1109, Fédération de Médecine Translationnelle (FMTS), Université de Strasbourg, Strasbourg 67085, France
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jayakrishna Ambati
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536, USA; Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
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Burger K, Gullerova M. Swiss army knives: non-canonical functions of nuclear Drosha and Dicer. Nat Rev Mol Cell Biol 2015; 16:417-30. [DOI: 10.1038/nrm3994] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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44
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Smalheiser NR. The RNA-centred view of the synapse: non-coding RNAs and synaptic plasticity. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0504. [PMID: 25135965 PMCID: PMC4142025 DOI: 10.1098/rstb.2013.0504] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
If mRNAs were the only RNAs made by a neuron, there would be a simple mapping of mRNAs to proteins. However, microRNAs and other non-coding RNAs (ncRNAs; endo-siRNAs, piRNAs, BC1, BC200, antisense and long ncRNAs, repeat-related transcripts, etc.) regulate mRNAs via effects on protein translation as well as transcriptional and epigenetic mechanisms. Not only are genes ON or OFF, but their ability to be translated can be turned ON or OFF at the level of synapses, supporting an enormous increase in information capacity. Here, I review evidence that ncRNAs are expressed pervasively within dendrites in mammalian brain; that some are activity-dependent and highly enriched near synapses; and that synaptic ncRNAs participate in plasticity responses including learning and memory. Ultimately, ncRNAs can be viewed as the post-it notes of the neuron. They have no literal meaning of their own, but derive their functions from where (and to what) they are stuck. This may explain, in part, why ncRNAs differ so dramatically from protein-coding genes, both in terms of the usual indicators of functionality and in terms of evolutionary constraints. ncRNAs do not appear to be direct mediators of synaptic transmission in the manner of neurotransmitters or receptors, yet they orchestrate synaptic plasticity—and may drive species-specific changes in cognition.
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Affiliation(s)
- Neil R Smalheiser
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA
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45
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Pickl JMA, Kamel W, Ciftci S, Punga T, Akusjärvi G. Opposite expression of CYP51A1 and its natural antisense transcript AluCYP51A1 in adenovirus type 37 infected retinal pigmented epithelial cells. FEBS Lett 2015; 589:1383-8. [PMID: 25907535 DOI: 10.1016/j.febslet.2015.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/26/2015] [Accepted: 04/10/2015] [Indexed: 11/29/2022]
Abstract
Cytochrome P450 family member CYP51A1 is a key enzyme in cholesterol biosynthesis whose deregulation is implicated in numerous diseases, including retinal degeneration. Here we describe that HAdV-37 infection leads to downregulation of CYP51A1 expression and overexpression of its antisense non-coding Alu element (AluCYP51A1) in retinal pigment epithelium (RPE) cells. This change in gene expression is associated with a reversed accumulation of a positive histone mark at the CYP51A1 and AluCYP51A1 promoters. Further, transient AluCYP51A1 RNA overexpression correlates with reduced CYP51A1 mRNA accumulation. Collectively, our data suggest that AluCYP51A1 might control CYP51A1 gene expression in HAdV-37-infected RPE cells.
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Affiliation(s)
- Julia Maria Anna Pickl
- Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, BMC, Box 582, 75123 Uppsala, Sweden
| | - Wael Kamel
- Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, BMC, Box 582, 75123 Uppsala, Sweden
| | - Sibel Ciftci
- Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, BMC, Box 582, 75123 Uppsala, Sweden
| | - Tanel Punga
- Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, BMC, Box 582, 75123 Uppsala, Sweden
| | - Göran Akusjärvi
- Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, BMC, Box 582, 75123 Uppsala, Sweden.
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46
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Ross JP, Kassir Z. The varied roles of nuclear argonaute-small RNA complexes and avenues for therapy. MOLECULAR THERAPY-NUCLEIC ACIDS 2014; 3:e203. [PMID: 25313622 PMCID: PMC4217078 DOI: 10.1038/mtna.2014.54] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/22/2014] [Indexed: 12/14/2022]
Abstract
Argonautes are highly conserved proteins found in almost all eukaryotes and some bacteria and archaea. In humans, there are eight argonaute proteins evenly distributed across two clades, the Ago clade (AGO1-4) and the Piwi clade (PIWIL1-4). The function of Ago proteins is best characterized by their role in RNA interference (RNAi) and cytoplasmic post-transcriptional gene silencing (PTGS) – which involves the loading of siRNA or miRNA into argonaute to direct silencing of genes at the posttranscriptional or translational level. However, nuclear-localized, as opposed to cytoplasmic, argonaute-small RNA complexes may also orchestrate the mechanistically very different process of transcriptional gene silencing, which results in prevention of transcription from a gene locus by the formation of silent chromatin domains. More recently, the role of argonaute in other aspects of epigenetic regulation of chromatin, alternative splicing and DNA repair is emerging. This review focuses on the activity of nuclear-localized short RNA-argonaute complexes in a mammalian setting and discusses recent in vivo studies employing nuclear-directed sRNA for therapeutic interventions. These studies heed the potential development of RNA-based drugs which induce epigenetic changes in the cell.
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Affiliation(s)
- Jason P Ross
- CSIRO Food and Nutrition Flagship, Sydney, New South Wales, Australia
| | - Zena Kassir
- 1] CSIRO Food and Nutrition Flagship, Sydney, New South Wales, Australia [2] Garvan Institute of Medical Research, Sydney, New South Wales, Australia
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47
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Abstract
Dicer is central to microRNA-mediated silencing and several other RNA interference phenomena that are profoundly embedded in cancer gene networks. Most recently, both germline and somatic mutations in DICER1 have been identified in diverse types of cancer. Although some of the mutations clearly reduce the dosage of this key enzyme, others dictate surprisingly specific changes in select classes of small RNAs. This Review reflects on the molecular properties of the Dicer enzymes in small RNA silencing pathways, and rationalizes the newly discovered mutations on the basis of the activities and functions of its determinants.
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Affiliation(s)
- William D Foulkes
- 1] Departments of Human Genetics, Medicine and Oncology, McGill University; Lady Davis Institute, Jewish General Hospital and Research Institute, McGill University Health Centre, Montreal, Quebec, Canada. [2]
| | | | - Thomas F Duchaine
- 1] Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada, H3A 1A3. [2]
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Berger A, Ivanova E, Gareau C, Scherrer A, Mazroui R, Strub K. Direct binding of the Alu binding protein dimer SRP9/14 to 40S ribosomal subunits promotes stress granule formation and is regulated by Alu RNA. Nucleic Acids Res 2014; 42:11203-17. [PMID: 25200073 PMCID: PMC4176187 DOI: 10.1093/nar/gku822] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Stress granules (SGs) are formed in response to stress, contain mRNAs, 40S ribosomal subunits, initiation factors, RNA-binding and signaling proteins, and promote cell survival. Our study describes a novel function of the protein heterodimer SRP9/14 and Alu RNA in SG formation and disassembly. In human cells, SRP9/14 exists assembled into SRP, bound to Alu RNA and as a free protein. SRP9/14, but not SRP, localizes to SGs following arsenite or hippuristanol treatment. Depletion of the protein decreases SG size and the number of SG-positive cells. Localization and function of SRP9/14 in SGs depend primarily on its ability to bind directly to the 40S subunit. Binding of SRP9/14 to 40S and Alu RNA is mutually exclusive indicating that the protein alone is bound to 40S in SGs and that Alu RNA might competitively regulate 40S binding. Indeed, by changing the effective Alu RNA concentration in the cell or by expressing an Alu RNA binding-defective protein we were able to influence SG formation and disassembly. Our findings suggest a model in which SRP9/14 binding to 40S promotes SG formation whereas the increase in cytoplasmic Alu RNA following stress promotes disassembly of SGs by disengaging SRP9/14 from 40S.
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Affiliation(s)
- A Berger
- Department of Cell Biology, University of Geneva, 1211 Geneva, Switzerland
| | - E Ivanova
- Department of Cell Biology, University of Geneva, 1211 Geneva, Switzerland
| | - C Gareau
- Département de biologie moléculaire, biochimie médicale et pathologie Université Laval, 4 Québec G1V0A6, Canada
| | - A Scherrer
- Department of Cell Biology, University of Geneva, 1211 Geneva, Switzerland
| | - R Mazroui
- Département de biologie moléculaire, biochimie médicale et pathologie Université Laval, 4 Québec G1V0A6, Canada
| | - K Strub
- Department of Cell Biology, University of Geneva, 1211 Geneva, Switzerland
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Dynamic Alu methylation during normal development, aging, and tumorigenesis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:784706. [PMID: 25243180 PMCID: PMC4163490 DOI: 10.1155/2014/784706] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 08/16/2014] [Indexed: 12/15/2022]
Abstract
DNA methylation primarily occurs on CpG dinucleotides and plays an important role in transcriptional regulations during tissue development and cell differentiation. Over 25% of CpG dinucleotides in the human genome reside within Alu elements, the most abundant human repeats. The methylation of Alu elements is an important mechanism to suppress Alu transcription and subsequent retrotransposition. Decades of studies revealed that Alu methylation is highly dynamic during early development and aging. Recently, many environmental factors were shown to have a great impact on Alu methylation. In addition, aberrant Alu methylation has been documented to be an early event in many tumors and Alu methylation levels have been associated with tumor aggressiveness. The assessment of the Alu methylation has become an important approach for early diagnosis and/or prognosis of cancer. This review focuses on the dynamic Alu methylation during development, aging, and tumor genesis. The cause and consequence of Alu methylation changes will be discussed.
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50
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Signaling through retinoic acid receptors in cardiac development: Doing the right things at the right times. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:94-111. [PMID: 25134739 DOI: 10.1016/j.bbagrm.2014.08.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 06/19/2014] [Accepted: 08/04/2014] [Indexed: 11/23/2022]
Abstract
Retinoic acid (RA) is a terpenoid that is synthesized from vitamin A/retinol (ROL) and binds to the nuclear receptors retinoic acid receptor (RAR)/retinoid X receptor (RXR) to control multiple developmental processes in vertebrates. The available clinical and experimental data provide uncontested evidence for the pleiotropic roles of RA signaling in development of multiple embryonic structures and organs such eyes, central nervous system, gonads, lungs and heart. The development of any of these above-mentioned embryonic organ systems can be effectively utilized to showcase the many strategies utilized by RA signaling. However, it is very likely that the strategies employed to transfer RA signals during cardiac development comprise the majority of the relevant and sophisticated ways through which retinoid signals can be conveyed in a complex biological system. Here, we provide the reader with arguments indicating that RA signaling is exquisitely regulated according to specific phases of cardiac development and that RA signaling itself is one of the major regulators of the timing of cardiac morphogenesis and differentiation. We will focus on the role of signaling by RA receptors (RARs) in early phases of heart development. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
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