1
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Shi Y, Shen F, Chen X, Sun M, Zhang P. Current understanding of circular RNAs in preeclampsia. Hypertens Res 2024; 47:1607-1619. [PMID: 38605141 DOI: 10.1038/s41440-024-01675-x] [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: 11/17/2023] [Revised: 02/28/2024] [Accepted: 03/22/2024] [Indexed: 04/13/2024]
Abstract
Preeclampsia (PE) is a multiple organ and system disease that seriously threatens the safety of the mother and infant during pregnancy, and has a profound impact on the morbidity and mortality of the mother and new babies. Presently, there are no remedies for cure of PE as to the mechanisms of PE are still unclear, and the only way to eliminate the symptoms is to deliver the placenta. Thus, new therapeutic targets for PE are urgently needed. Approximately 95% of human transcripts are thought to be non-coding RNAs, and the roles of them are to be increasingly recognized of great importance in various biological processes. Circular RNAs (circRNAs) are a class of non-coding RNAs, with no 5' caps and 3' polyadenylated tails, commonly produced by back-splicing of exons. The structure of circRNAs makes them more stable than their counterparts. Increasing evidence shows that circRNAs are involved in the pathogenesis of PE, but the biogenesis, functions, and mechanisms of circRNAs in PE are poorly understood. In the present review, we mainly summarize the biogenesis, functions, and possible mechanisms of circRNAs in the development and progression of PE, as well as opportunities and challenges in the treatment and prevention of PE.
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Affiliation(s)
- Yajun Shi
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Fangrong Shen
- Obstetrics and Gynecology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xionghui Chen
- Department of Emergency Medicine, The First Affiliated Hospital of Soochow University, Suzhou, China.
- Institute of Trauma Medicine, Soochow University, Suzhou, China.
- Jiangsu Provincial Medical Innovation Center of Trauma Medicine, Suzhou, China.
| | - Miao Sun
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China.
| | - Pengjie Zhang
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China.
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2
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Wedge E, Ahmadov U, Hansen TB, Gao Z, Tulstrup M, Côme C, Nonavinkere Srivatsan S, Ahmed T, Jespersen JS, Schlotmann BC, Schöllkopf C, Raaschou-Jensen K, Ødum N, Kjems J, Bak RO, Walter MJ, Grønbæk K, Kristensen LS. Impact of U2AF1 mutations on circular RNA expression in myelodysplastic neoplasms. Leukemia 2023; 37:1113-1125. [PMID: 36922625 DOI: 10.1038/s41375-023-01866-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/16/2023] [Accepted: 02/28/2023] [Indexed: 03/18/2023]
Abstract
Mutations in U2AF1 are relatively common in myelodysplastic neoplasms (MDS) and are associated with an inferior prognosis, but the molecular mechanisms underlying this are not fully elucidated. Circular RNAs (circRNAs) have been implicated in cancer, but it is unknown how mutations in splicing factors may impact on circRNA biogenesis. Here, we used RNA-sequencing to investigate the effects of U2AF1 mutations on circRNA expression in K562 cells with a doxycycline-inducible U2AF1S34 mutation, in a mouse model with a doxycycline-inducible U2AF1S34 mutation, and in FACS-sorted CD34+ bone marrow cells from MDS patients with either U2AF1S34 or U2AF1Q157 mutations. In all contexts, we found an increase in global circRNA levels in the U2AF1-mutated setting, which was independent of expression changes in the cognate linear host genes. In patients, the U2AF1S34 and U2AF1Q157 mutations were both associated with an overall increased expression of circRNAs. circRNAs generated by a non-Alu-mediated mechanism generally showed the largest increase in expression levels. Several well-described cancer-associated circRNAs, including circZNF609 and circCSNK1G3, were upregulated in MDS patients with U2AF1 mutations compared to U2AF1-wildtype MDS controls. In conclusion, high circRNA expression is observed in association with U2AF1 mutations in three biological systems, presenting an interesting possibility for biomarker and therapeutic investigation.
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Affiliation(s)
- Eileen Wedge
- Department of Hematology, Copenhagen University Hospital, Copenhagen, Denmark
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
| | - Ulvi Ahmadov
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Thomas B Hansen
- Department of Molecular Biology and Genetics, Aarhus, Denmark
| | - Zongliang Gao
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Morten Tulstrup
- Department of Hematology, Copenhagen University Hospital, Copenhagen, Denmark
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
| | - Christophe Côme
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
| | | | - Tanzir Ahmed
- Division of Oncology, Washington University School of Medicine, St Louis, MO, USA
| | - Jakob S Jespersen
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
- The Finsen Laboratory, Copenhagen University Hospital, Copenhagen, Denmark
| | - Balthasar C Schlotmann
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark
- The Finsen Laboratory, Copenhagen University Hospital, Copenhagen, Denmark
| | - Claudia Schöllkopf
- Department of Hematology, Copenhagen University Hospital, Copenhagen, Denmark
| | | | - Niels Ødum
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Kjems
- Department of Molecular Biology and Genetics, Aarhus, Denmark
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark
| | - Rasmus O Bak
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Matthew J Walter
- Division of Oncology, Washington University School of Medicine, St Louis, MO, USA
| | - Kirsten Grønbæk
- Department of Hematology, Copenhagen University Hospital, Copenhagen, Denmark.
- Biotech Research and Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark.
- The Danish Stem Cell Center (Danstem), University of Copenhagen, Copenhagen, Denmark.
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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3
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Xu X, Du T, Mao W, Li X, Ye CY, Zhu QH, Fan L, Chu Q. PlantcircBase 7.0: Full-length transcripts and conservation of plant circRNAs. PLANT COMMUNICATIONS 2022; 3:100343. [PMID: 35637632 PMCID: PMC9284285 DOI: 10.1016/j.xplc.2022.100343] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/13/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Circular RNA (circRNA) is a special type of non-coding RNA that participates in diverse biological processes in both animals and plants. Five years ago, we developed a comprehensive plant circRNA database (PlantcircBase), which has attracted much attention from the plant circRNA community. Here, we report an updated PlantcircBase (v.7.0), which contains 171,118 circRNAs from 21 plant species. Over 31,000 of the circRNAs have full-length sequences constructed based on analysis of 749 bulk RNA sequencing (RNA-seq) datasets downloaded from the public domain and Nanopore long-read sequencing results of rice RNAs newly generated in this study. A plant multiple conservation score (PMCS), based on the conservation of both sequence and expression profiles, was calculated for each circRNA to quantify and compare the conservation of all circRNAs. A new parameter, plant circRNA confidence level (PCCL), is introduced to measure the identity reliability of each circRNA based on experimental validation results and the number of references that support the circRNA. All this information and other details of circRNAs can be browsed, searched, and downloaded from PlantcircBase 7.0, which also provides online bioinformatics tools for visualization and sequence alignment. PlantcircBase 7.0 is publicly and freely accessible at http://ibi.zju.edu.cn/plantcircbase/.
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Affiliation(s)
- Xiaoxu Xu
- Institute of Crop Science & Institute of Bioinformatics, Zhejiang University, Hangzhou 310058, China; Shandong (Linyi) Institute of Modern Agriculture of Zhejiang University, Linyi 310014, China
| | - Tianyu Du
- Institute of Crop Science & Institute of Bioinformatics, Zhejiang University, Hangzhou 310058, China; Shandong (Linyi) Institute of Modern Agriculture of Zhejiang University, Linyi 310014, China
| | - Weihua Mao
- Analysis Center of Agrobiology and Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Xiaohan Li
- Institute of Crop Science & Institute of Bioinformatics, Zhejiang University, Hangzhou 310058, China
| | - Chu-Yu Ye
- Institute of Crop Science & Institute of Bioinformatics, Zhejiang University, Hangzhou 310058, China
| | - Qian-Hao Zhu
- CSIRO Agriculture and Food, Black Mountain Laboratories, Canberra, ACT 2601, Australia
| | - Longjiang Fan
- Institute of Crop Science & Institute of Bioinformatics, Zhejiang University, Hangzhou 310058, China; Shandong (Linyi) Institute of Modern Agriculture of Zhejiang University, Linyi 310014, China
| | - Qinjie Chu
- Institute of Crop Science & Institute of Bioinformatics, Zhejiang University, Hangzhou 310058, China.
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4
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Insights into the multifaceted role of circular RNAs: implications for Parkinson's disease pathogenesis and diagnosis. NPJ Parkinsons Dis 2022; 8:7. [PMID: 35013342 PMCID: PMC8748951 DOI: 10.1038/s41531-021-00265-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 12/10/2021] [Indexed: 12/13/2022] Open
Abstract
Parkinson's disease (PD) is a complex, age-related, neurodegenerative disease whose etiology, pathology, and clinical manifestations remain incompletely understood. As a result, care focuses primarily on symptoms relief. Circular RNAs (circRNAs) are a large class of mostly noncoding RNAs that accumulate with aging in the brain and are increasingly shown to regulate all aspects of neuronal and glial development and function. They are generated by the spliceosome through the backsplicing of linear RNA. Although their biological role remains largely unknown, they have been shown to regulate transcription and splicing, act as decoys for microRNAs and RNA binding proteins, used as templates for translation, and serve as scaffolding platforms for signaling components. Considering that they are stable, diverse, and detectable in easily accessible biofluids, they are deemed promising biomarkers for diagnosing diseases. CircRNAs are differentially expressed in the brain of patients with PD, and growing evidence suggests that they regulate PD pathogenetic processes. Here, the biogenesis, expression, degradation, and detection of circRNAs, as well as their proposed functions, are reviewed. Thereafter, research linking circRNAs to PD-related processes, including aging, alpha-synuclein dysregulation, neuroinflammation, and oxidative stress is highlighted, followed by recent evidence for their use as prognostic and diagnostic biomarkers for PD.
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5
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Ravanidis S, Bougea A, Karampatsi D, Papagiannakis N, Maniati M, Stefanis L, Doxakis E. Differentially Expressed Circular RNAs in Peripheral Blood Mononuclear Cells of Patients with Parkinson's Disease. Mov Disord 2021; 36:1170-1179. [PMID: 33433033 PMCID: PMC8248110 DOI: 10.1002/mds.28467] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 11/18/2020] [Accepted: 12/08/2020] [Indexed: 12/12/2022] Open
Abstract
Background New noninvasive and affordable molecular approaches that will complement current practices and increase the accuracy of Parkinson's disease (PD) diagnosis are urgently needed. Circular RNAs (circRNAs) are stable noncoding RNAs that accumulate with aging in neurons and are increasingly shown to regulate all aspects of neuronal development and function. Objectives Τhe aims of this study were to identify differentially expressed circRNAs in blood mononuclear cells of patients with idiopathic PD and explore the competing endogenous RNA networks affected. Methods Eighty‐seven circRNAs were initially selected based on relatively high gene expression in the human brain. More than half of these were readily detectable in blood mononuclear cells using real‐time reverse transcription‐polymerase chain reaction. Comparative expression analysis was then performed in blood mononuclear cells from 60 control subjects and 60 idiopathic subjects with PD. Results Six circRNAs were significantly down‐regulated in patients with PD. The classifier that best distinguished PD consisted of four circRNAs with an area under the curve of 0.84. Cross‐linking immunoprecipitation‐sequencing data revealed that the RNA‐binding proteins bound by most of the deregulated circRNAs include the neurodegeneration‐associated FUS, TDP43, FMR1, and ATXN2. MicroRNAs predicted to be sequestered by most deregulated circRNAs have the Gene Ontology categories “protein modification” and “transcription factor activity” mostly enriched. Conclusions This is the first study that identifies specific circRNAs that may serve as diagnostic biomarkers for PD. Because they are highly expressed in the brain and are derived from genes with essential brain functions, they may also hint on the PD pathways affected. © 2021 Biomedical Research Foundation, Academy of Athens. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Stylianos Ravanidis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Anastasia Bougea
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,Center of Clinical Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Dimitra Karampatsi
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Nikolaos Papagiannakis
- Center of Clinical Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Matina Maniati
- Center of Clinical Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Leonidas Stefanis
- Center of Clinical Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Epaminondas Doxakis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
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6
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Mapping a Circular RNA-microRNA-mRNA-Signaling Regulatory Axis That Modulates Stemness Properties of Cancer Stem Cell Populations in Colorectal Cancer Spheroid Cells. Int J Mol Sci 2020; 21:ijms21217864. [PMID: 33114016 PMCID: PMC7672619 DOI: 10.3390/ijms21217864] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 02/08/2023] Open
Abstract
Spheroidal cancer cell cultures have been used to enrich cancer stem cells (CSC), which are thought to contribute to important clinical features of tumors. This study aimed to map the regulatory networks driven by circular RNAs (circRNAs) in CSC-enriched colorectal cancer (CRC) spheroid cells. The spheroid cells established from two CRC cell lines acquired stemness properties in pluripotency gene expression and multi-lineage differentiation capacity. Genome-wide sequencing identified 1503 and 636 circRNAs specific to the CRC parental and spheroid cells, respectively. In the CRC spheroids, algorithmic analyses unveiled a core network of mRNAs involved in modulating stemness-associated signaling pathways, driven by a circRNA–microRNA (miRNA)–mRNA axis. The two major circRNAs, hsa_circ_0066631 and hsa_circ_0082096, in this network were significantly up-regulated in expression levels in the spheroid cells. The two circRNAs were predicted to target and were experimentally shown to down-regulate miR-140-3p, miR-224, miR-382, miR-548c-3p and miR-579, confirming circRNA sponging of the targeted miRNAs. Furthermore, the affected miRNAs were demonstrated to inhibit degradation of six mRNA targets, viz. ACVR1C/ALK7, FZD3, IL6ST/GP130, SKIL/SNON, SMAD2 and WNT5, in the CRC spheroid cells. These mRNAs encode proteins that are reported to variously regulate the GP130/Stat, Activin/Nodal, TGF-β/SMAD or Wnt/β-catenin signaling pathways in controlling various aspects of CSC stemness. Using the CRC spheroid cell model, the novel circRNA–miRNA–mRNA axis mapped in this work forms the foundation for the elucidation of the molecular mechanisms of the complex cellular and biochemical processes that determine CSC stemness properties of cancer cells, and possibly for designing therapeutic strategies for CRC treatment by targeting CSC.
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7
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Jadhav SP, Kumari N, Ng L, Tan PF, Yeo-Teh NSL, Goh Y, Fam WN, Tng JQ, Tian JS, Koh BTH, Chun CM, Wang W, Chng WJ, Fullwood MJ, Guccione E, Karnani N, Tenen DG, Jha S. circASXL1-1 regulates BAP1 deubiquitinase activity in leukemia. Haematologica 2019; 105:e343-e348. [PMID: 31780633 DOI: 10.3324/haematol.2019.225961] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Shweta Pradip Jadhav
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Nishi Kumari
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Larry Ng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Pei Fang Tan
- Singapore Institute for Clinical Sciences, A*STAR, Singapore
| | - Nicole Shu Ling Yeo-Teh
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,National University of Singapore Graduate School for Integrative Sciences and Engineering, Singapore
| | - Yufen Goh
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Wee Nih Fam
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Jia Qi Tng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Johann Shane Tian
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Bryan T H Koh
- Department of Orthopedic Surgery, National University Health Systems, Singapore
| | - Chan Ming Chun
- Department of Orthopedic Surgery, National University Health Systems, Singapore
| | - Wilson Wang
- Department of Orthopedic Surgery, National University of Singapore, Singapore
| | - Wee Joo Chng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,Department of Hematology-Oncology, National University Cancer Institute, Singapore
| | - Melissa Jane Fullwood
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,School of Biological Sciences, Nanyang Technological Institute, Singapore.,Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore
| | - Ernesto Guccione
- Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore.,Tisch Cancer Institute, Department of Oncological Sciences and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Neerja Karnani
- Singapore Institute for Clinical Sciences, A*STAR, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Daniel G Tenen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Sudhakar Jha
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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8
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Gao M, Liu Y, Wang Y, Zhang X, Dong S, Liu X. Newly identified APN splice isoforms suggest novel splicing mechanisms may underlie circRNA circularization in moth. FEBS Open Bio 2019; 9:1521-1535. [PMID: 31237102 PMCID: PMC6722899 DOI: 10.1002/2211-5463.12689] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 06/04/2019] [Accepted: 06/21/2019] [Indexed: 12/11/2022] Open
Abstract
Circular RNA (circRNA) have long been considered by-products of splicing errors, but the coordination of RNA transcription and exon circularization events remains poorly understood. Here, we investigated this question using genes encoding aminopeptidases N (APNs), which are receptors of Bacillus thuringiensis toxins, in the cotton bollworm, Helicoverpa armigera. We cloned and sequenced the cDNA of ten APN genes (HaAPN1-10) located in the same APN gene cluster, and detected 20 and 14 novel splicing isoforms with exon skipping in HaAPN1 and HaAPN3, respectively, whereas no or very few variants were found in the remaining genes. Further study identified 14 and 6 circular RNA (circRNA) in HaAPN1 and HaAPN3, respectively. Neither novel splicing isoforms nor circRNA were detected in HaAPN2 and HaAPN5. Distinct from the conventional GT/AG splicing signal, short co-directional repeats were involved in the splicing of the linear and circular isoforms of HaAPN1 and HaAPN3. Identification of the splice sites revealed that the linear isoforms may be related in some way to the circularization. Moreover, phylogenetic analysis and detection of circRNA of the APN gene of the diamondback moth, Plutella xylostella (PxAPN3), showed that circRNA formation is relatively conserved during the lepidopteran evolutionary process. These results contribute to an improved understanding of lepidopteran APNs and this novel class of insect circRNA.
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Affiliation(s)
- Meijing Gao
- Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yuan Liu
- Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
| | - Yun Wang
- Horticulture Department, Jinling Institute of Technology, Nanjing, China
| | - Xiao Zhang
- Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Sa Dong
- School of Horticulture and Plant Protection, Yangzhou University, China
| | - Xianjin Liu
- Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
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9
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Abstract
As a newly discovered type of RNA, circular RNAs (circRNAs) are widespread throughout the eukaryotic genome. The expression of circRNAs is regulated by both cis-elements and trans-factors, and the expression pattern of circRNAs is cell type- and disease-specific. Similar to other types of non-coding RNAs, functions of circRNAs are also versatile. CircRNAs have been reported previously to function as microRNA (miRNA) sponges, protein sponges, coding RNAs or scaffolds for protein complexes. Recently, several circRNAs have been reported to play important roles in human malignancies, including glioma. Here, we reviewed several reports related to circRNAs and glioma, as well as the potential diagnostic and therapeutic applications of circRNAs in brain cancer. In general, some circRNAs, such as circSMARCA5 and circCFH, are found to be expressed in a glioma-specific pattern, these circRNAs may be used as tumor biomarkers. In addition, some circRNAs have been found to play oncogenic roles in glioma (e.g., circNFIX and circNT5E), whereas others have been reported to function as tumor suppressors (e.g., circFBXW7 and circSHPRH). Furthermore, circRNA is a good tool for protein expression because of its higher stability compared to linear RNAs. Thus, circRNAs may also be an ideal choice for gene/protein delivery in future brain cancer therapies. There are some challenges in circRNA research in glioma and other diseases. Research related to circRNAs in glioma is comparatively new and many mysteries remain to be solved.
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Affiliation(s)
- Jinglei Liu
- Department of Neurosurgery, The First Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou 510080, China
| | - Kun Zhao
- Department of Neurosurgery, The First Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou 510080, China
| | - Nunu Huang
- Department of Neurosurgery, The First Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou 510080, China
| | - Nu Zhang
- Department of Neurosurgery, The First Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou 510080, China
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10
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Holdt LM, Kohlmaier A, Teupser D. Circular RNAs as Therapeutic Agents and Targets. Front Physiol 2018; 9:1262. [PMID: 30356745 PMCID: PMC6189416 DOI: 10.3389/fphys.2018.01262] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/21/2018] [Indexed: 12/26/2022] Open
Abstract
It has recently been reported that thousands of covalently linked circular RNAs (circRNAs) are expressed from human genomes. circRNAs emerge during RNA splicing. circRNAs are circularized in a reaction termed "backsplicing," whereby the spliceosome fuses a splice donor site in a downstream exon to a splice acceptor site in an upstream exon. Although a young field of research, first studies indicate that backsplicing is not an erroneous reaction of the spliceosome. Instead, circRNAs are produced in cells with high cell-type specificity and can exert biologically meaningful and specific functions. These observations and the finding that circRNAs are stable against exonucleolytic decay are raising the question whether circRNAs may be relevant as therapeutic agents and targets. In this review, we start out with a short introduction into classification, biogenesis and general molecular mechanisms of circRNAs. We then describe reports, where manipulating circRNA abundance has been shown to have therapeutic value in animal disease models in vivo, with a focus on cardiovascular disease (CVD). Starting from existing approaches, we outline particular challenges and opportunities for future circRNA-based therapeutic approaches that exploit stability and molecular effector functions of native circRNAs. We end with considerations which designer functions could be engineered into artificial therapeutic circular RNAs.
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Affiliation(s)
| | | | - Daniel Teupser
- Institute of Laboratory Medicine, University Hospital, Ludwig Maximilian University of Munich (LMU), Munich, Germany
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11
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Holdt LM, Kohlmaier A, Teupser D. Molecular functions and specific roles of circRNAs in the cardiovascular system. Noncoding RNA Res 2018; 3:75-98. [PMID: 30159442 PMCID: PMC6096412 DOI: 10.1016/j.ncrna.2018.05.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 05/11/2018] [Accepted: 05/11/2018] [Indexed: 12/25/2022] Open
Abstract
As part of the superfamily of long noncoding RNAs, circular RNAs (circRNAs) are emerging as a new type of regulatory molecules that partake in gene expression control. Here, we review the current knowledge about circRNAs in cardiovascular disease. CircRNAs are not only associated with different types of cardiovascular disease, but they have also been identified as intracellular effector molecules for pathophysiological changes in cardiovascular tissues, and as cardiovascular biomarkers. This evidence is put in the context of the current understanding of general circRNA biogenesis and of known interactions of circRNAs with DNA, RNA, and proteins.
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Affiliation(s)
- Lesca M. Holdt
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Germany
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12
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Holdt LM, Kohlmaier A, Teupser D. Molecular roles and function of circular RNAs in eukaryotic cells. Cell Mol Life Sci 2018; 75:1071-1098. [PMID: 29116363 PMCID: PMC5814467 DOI: 10.1007/s00018-017-2688-5] [Citation(s) in RCA: 238] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/29/2017] [Accepted: 10/17/2017] [Indexed: 12/27/2022]
Abstract
Protein-coding and noncoding genes in eukaryotes are typically expressed as linear messenger RNAs, with exons arranged colinearly to their genomic order. Recent advances in sequencing and in mapping RNA reads to reference genomes have revealed that thousands of genes express also covalently closed circular RNAs. Many of these circRNAs are stable and contain exons, but are not translated into proteins. Here, we review the emerging understanding that both, circRNAs produced by co- and posttranscriptional head-to-tail "backsplicing" of a downstream splice donor to a more upstream splice acceptor, as well as circRNAs generated from intronic lariats during colinear splicing, may exhibit physiologically relevant regulatory functions in eukaryotes. We describe how circRNAs impact gene expression of their host gene locus by affecting transcriptional initiation and elongation or splicing, and how they partake in controlling the function of other molecules, for example by interacting with microRNAs and proteins. We conclude with an outlook how circRNA dysregulation affects disease, and how the stability of circRNAs might be exploited in biomedical applications.
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Affiliation(s)
- Lesca M Holdt
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany.
| | - Alexander Kohlmaier
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
- Faculty of Biology, Genetics, LMU Munich, Großhaderner Str. 2-4, 82152, Martinsried, Germany
| | - Daniel Teupser
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany
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Dinan AM, Atkins JF, Firth AE. ASXL gain-of-function truncation mutants: defective and dysregulated forms of a natural ribosomal frameshifting product? Biol Direct 2017; 12:24. [PMID: 29037253 PMCID: PMC5644247 DOI: 10.1186/s13062-017-0195-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/04/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Programmed ribosomal frameshifting (PRF) is a gene expression mechanism which enables the translation of two N-terminally coincident, C-terminally distinct protein products from a single mRNA. Many viruses utilize PRF to control or regulate gene expression, but very few phylogenetically conserved examples are known in vertebrate genes. Additional sex combs-like (ASXL) genes 1 and 2 encode important epigenetic and transcriptional regulatory proteins that control the expression of homeotic genes during key developmental stages. Here we describe an ~150-codon overlapping ORF (termed TF) in ASXL1 and ASXL2 that, with few exceptions, is conserved throughout vertebrates. RESULTS Conservation of the TF ORF, strong suppression of synonymous site variation in the overlap region, and the completely conserved presence of an EH[N/S]Y motif (a known binding site for Host Cell Factor-1, HCF-1, an epigenetic regulatory factor), all indicate that TF is a protein-coding sequence. A highly conserved UCC_UUU_CGU sequence (identical to the known site of +1 ribosomal frameshifting for influenza virus PA-X expression) occurs at the 5' end of the region of enhanced synonymous site conservation in ASXL1. Similarly, a highly conserved RG_GUC_UCU sequence (identical to a known site of -2 ribosomal frameshifting for arterivirus nsp2TF expression) occurs at the 5' end of the region of enhanced synonymous site conservation in ASXL2. CONCLUSIONS Due to a lack of appropriate splice forms, or initiation sites, the most plausible mechanism for translation of the ASXL1 and 2 TF regions is ribosomal frameshifting, resulting in a transframe fusion of the N-terminal half of ASXL1 or 2 to the TF product, termed ASXL-TF. Truncation or frameshift mutants of ASXL are linked to myeloid malignancies and genetic diseases, such as Bohring-Opitz syndrome, likely at least in part as a result of gain-of-function or dominant-negative effects. Our hypothesis now indicates that these disease-associated mutant forms represent overexpressed defective versions of ASXL-TF. REVIEWERS This article was reviewed by Laurence Hurst and Eugene Koonin.
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Affiliation(s)
- Adam M Dinan
- Department of Pathology, Division of Virology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, T12 YT57, Cork, Ireland.,Department of Human Genetics, University of Utah, Salt Lake City, UT, 84112, USA
| | - Andrew E Firth
- Department of Pathology, Division of Virology, University of Cambridge, Cambridge, CB2 1QP, UK.
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