A Manually-Curated Database of Experimentally
Total Page:16
File Type:pdf, Size:1020Kb
D118–D126 Nucleic Acids Research, 2020, Vol. 48, Database issue Published online 12 November 2019 doi: 10.1093/nar/gkz985 LncTarD: a manually-curated database of experimentally-supported functional lncRNA–target regulations in human diseases Hongying Zhao1,†,JianShi1,†, Yunpeng Zhang1,†, Aimin Xie1, Lei Yu1, Caiyu Zhang1, Junjie Lei1, Haotian Xu1, Zhijun Leng1, Tengyue Li1, Waidong Huang1, Shihua Lin1, Li Wang1,*, Yun Xiao1,* and Xia Li1,2,* 1College of Bioinformatics Science and Technology, Harbin Medical University, Harbin 150081, China and 2College of Bioinformatics, Hainan Medical University, Haikou 570100, China Received July 31, 2019; Revised October 12, 2019; Editorial Decision October 14, 2019; Accepted October 16, 2019 ABSTRACT standing of functions and molecular mechanisms of lncRNA deregulation in human disease, which will Long non-coding RNAs (lncRNAs) are associated help to identify novel and sensitive biomarkers and with human diseases. Although lncRNA–disease as- therapeutic targets. sociations have received significant attention, no online repository is available to collect lncRNA- mediated regulatory mechanisms, key downstream INTRODUCTION targets, and important biological functions driven > by disease-related lncRNAs in human diseases. Studies have shown that 98% of the human genome does not encode protein sequences. In particular, long non- We thus developed LncTarD (http://biocc.hrbmu. coding RNAs (lncRNAs) are a class of important non- edu.cn/LncTarD/ or http://bio-bigdata.hrbmu.edu.cn/ coding RNAs with lengths >200 nt (1). With the rapid de- LncTarD), a manually-curated database that pro- velopment of both experimental technology and compu- vides a comprehensive resource of key lncRNA– tational methods, the number of lncRNAs has increased target regulations, lncRNA-influenced functions, and drastically over the past few years. Recent advances in lncRNA-mediated regulatory mechanisms in human lncRNA-related research concerning their sequence, ex- diseases. LncTarD offers (i) 2822 key lncRNA–target pression, and function have led to the creation of several regulations involving 475 lncRNAs and 1039 tar- publicly available lncRNA resources. For example, LNCi- gets associated with 177 human diseases; (ii) 1613 pedia 5 (lncRNA sequence and annotation) (2), LNCedit- experimentally-supported functional regulations and ing (functional prediction of RNA editing in lncRNAs) (3), 1209 expression associations in human diseases; lncRNASNP2 (single nucleotide polymorphisms in lncR- NAs) (4), lncRNome (lncRNA annotation) (5), lncRNA- (iii) important biological functions driven by disease- tor (lncRNA sequence, annotation, gene expression, pro- related lncRNAs in human diseases; (iv) lncRNA– tein binding and conservation) (6) and lncRNAdb v2.0 target regulations responsible for drug resistance or (lncRNA sequence, expression data and the literature) (7) sensitivity in human diseases and (v) lncRNA mi- all focus on the basic information and functional char- croarray, lncRNA sequence data and transcriptome acteristics of lncRNAs. LncRNA2Target v2.0 (predicted data of an 11 373 pan-cancer patient cohort from lncRNA–target relationships) (8), ChIPBase v2.0 (pre- TCGA to help characterize the functional dynamics dicted TF-ncRNA regulations) (9), LncReg (experimentally of these lncRNA–target regulations. LncTarD also validated lncRNA-associated regulatory entries) (10), and provides a user-friendly interface to conveniently DIANA-LncBase v2 (experimentally verified and predicted browse, search, and download data. LncTarD will miRNA-lncRNA pairs) (11) focus on lncRNA-associated be a useful resource platform for the further under- regulatory entries without disease information. More im- portantly, the involvement of lncRNAs in numerous hu- *To whom correspondence should be addressed. Tel: +86 451 86615922; Email: [email protected] Correspondence may also be addressed to Yun Xiao. Tel: +86451 86615922; Email: [email protected] Correspondence may also be addressed to Xia Li. Tel: +86451 86615922; Email: [email protected] †The authors wish it to be known that, in their opinion, the first three authors should be regarded as Joint First Authors. C The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. Nucleic Acids Research, 2020, Vol. 48, Database issue D119 man diseases, especially in cancers, has received a great DATA COLLECTION, PROCESSING AND IMPLEMEN- deal of attention. Recently, experimentally-supported or TATION predicted lncRNA–disease associations have been stored in First, we searched the PubMed literature database using publicly available databases, such as LncRNADisease 2.0 the master keywords ‘long noncoding RNA,’ ‘lncRNA’ (experimentally-supported and predicted lncRNA–disease and ‘lincRNA,’ in combination with ‘cancer,’ ‘tumor,’ ‘dis- associations) (12) and Lnc2Cancer v2.0 (experimentally ease,’ ‘carcinoma,’ ‘dysfunction,’ ‘proliferation,’ ‘invasive- supported lncRNA-cancer associations) (13). However, im- ness,’ ‘invasion,’ ‘migration,’ ‘patient,’ ‘patients,’ ‘abnormal- portant information concerning key downstream targets, ities,’ ‘syndrome,’ ‘disorder’ and ‘human.’ PubMed arti- biological functions driven by disease-related lncRNAs, as cles were identified by searching these keywords in full well as lncRNA-dependent mechanisms of gene expression text on PubMed. We then manually screened the abstracts deregulation in human diseases still remain hidden in a large in order to extract the entries that described associations amount of dispersed literature, and have yet to be exten- between lncRNA–target regulations and human diseases sively and systematically collected. from 8866 PubMed publications (17). Next, the full text Indeed, anomalies in lncRNA-dependent gene- of these articles was double-reviewed to extract the de- regulatory mechanisms contribute to the occurrence tailed lncRNA-mediated regulatory mechanisms in hu- and progression of human diseases. For instance, the man diseases. Only the articles meeting all of the follow- lncRNA HOTAIR could be involved in the downregula- ing criteria were retained: (i) lncRNAs associated with tion of HOX loci through H3K27 trimethylation, thereby human diseases; (ii) identification of key target genes of regulating breast invasion and metastasis by binding to the lncRNA and (iii) mention of important biological polycomb repressive complex 2 (PRC2) (14). In addition functions affected by lncRNA–target regulations. Through to the epigenetic regulation of genes, several lncRNAs strict screening, 1862 articles comprised relevant informa- could act as ceRNAs by sponging miRNAs to reduce their tion that was incorporated into the database. Second, we inhibitory effect on their target protein-coding mRNAs, retrieved the lncRNA, target and disease names, direc- thus participating in post-transcriptional processing. For tion of regulation (positively-F/E or negatively-F/E), ex- example, SNHG16 promotes epithelial-to-mesenchymal perimental method for each interaction, expression pattern transition (EMT) in esophageal squamous cell carcinoma of lncRNA (upregulated or downregulated), experimental (ESCC) by competing with miR-140-5p to positively method and lncRNA microarray, lncRNA sequence data regulate its key target ZEB1 (15,16). Understanding the for lncRNA dysregulation, lncRNA coordinates, positively- precise molecular mechanisms by which lncRNA regulates or negatively-influenced biological functions emphasized downstream key mediators to affect important biological by the original reference articles, lncRNA-mediated regu- functions is necessary to help explain the roles of lncRNAs latory mechanisms (such as ceRNA or sponge, and epi- in the pathogenesis of human diseases and will be a critical genetic regulation), and a brief description of functional first step in exploring these potential new avenues in cancer lncRNA–target regulation in human diseases from the orig- therapy. However, such important information concerning inal studies and reference information. Notably, we ex- how these disease-related lncRNAs contribute to patho- tracted and recorded the cancer subtype information from genesis, which targets are the downstream key mediators, the PubMed literature. We used negatively-F (or positively- and which functions are affected has been largely ignored. F) and negatively-E (or positively-E) to represent negatively To fill this gap, we therefore developed LncTarD, a novel (or positively) affecting function and expression, respec- database that collects and integrates disease-associated tively. For example, lncRNA:miRNA sponge interactions lncRNA–target regulations into a comprehensive resource are annotated as ‘negatively-F,’ which potentially means for the first time (Supplementary Table S1). The cur- that miRNA function (not expression) is negatively af- rent version of LncTarD includes 2822 disease-associated fected. In other regulations, ‘negatively-E’ would mean the lncRNA–target regulations, including 1613 experimentally- reduction of target expression. Only high-quality functional supported functional regulations and 1209 expression as- regulations with strong experimental evidence such as RNA sociations, involving 475 lncRNAs and 1039 targets