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da Silva Rosa SC, Barzegar Behrooz A, Guedes S, Vitorino R, Ghavami S. Prioritization of genes for translation: a computational approach. Expert Rev Proteomics 2024; 21:125-147. [PMID: 38563427 DOI: 10.1080/14789450.2024.2337004] [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: 05/26/2023] [Accepted: 02/21/2024] [Indexed: 04/04/2024]
Abstract
INTRODUCTION Gene identification for genetic diseases is critical for the development of new diagnostic approaches and personalized treatment options. Prioritization of gene translation is an important consideration in the molecular biology field, allowing researchers to focus on the most promising candidates for further investigation. AREAS COVERED In this paper, we discussed different approaches to prioritize genes for translation, including the use of computational tools and machine learning algorithms, as well as experimental techniques such as knockdown and overexpression studies. We also explored the potential biases and limitations of these approaches and proposed strategies to improve the accuracy and reliability of gene prioritization methods. Although numerous computational methods have been developed for this purpose, there is a need for computational methods that incorporate tissue-specific information to enable more accurate prioritization of candidate genes. Such methods should provide tissue-specific predictions, insights into underlying disease mechanisms, and more accurate prioritization of genes. EXPERT OPINION Using advanced computational tools and machine learning algorithms to prioritize genes, we can identify potential targets for therapeutic intervention of complex diseases. This represents an up-and-coming method for drug development and personalized medicine.
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Affiliation(s)
- Simone C da Silva Rosa
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Science, University of Manitoba, Winnipeg, Canada
| | - Amir Barzegar Behrooz
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Science, University of Manitoba, Winnipeg, Canada
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Sofia Guedes
- LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Rui Vitorino
- LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, Aveiro, Portugal
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
- UnIC@RISE, Department of Surgery and Physiology, Faculty of Medicine of the University of Porto, Porto, Portugal
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Science, University of Manitoba, Winnipeg, Canada
- Faculty of Medicine in Zabrze, Academia of Silesia, Katowice, Poland
- Research Institute of Oncology and Hematology, Cancer Care Manitoba, University of Manitoba, Winnipeg, Canada
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Azadifar S, Ahmadi A. A novel candidate disease gene prioritization method using deep graph convolutional networks and semi-supervised learning. BMC Bioinformatics 2022; 23:422. [PMID: 36241966 PMCID: PMC9563530 DOI: 10.1186/s12859-022-04954-x] [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: 07/12/2022] [Accepted: 09/20/2022] [Indexed: 11/18/2022] Open
Abstract
Background Selecting and prioritizing candidate disease genes is necessary before conducting laboratory studies as identifying disease genes from a large number of candidate genes using laboratory methods, is a very costly and time-consuming task. There are many machine learning-based gene prioritization methods. These methods differ in various aspects including the feature vectors of genes, the used datasets with different structures, and the learning model. Creating a suitable feature vector for genes and an appropriate learning model on a variety of data with different and non-Euclidean structures, including graphs, as well as the lack of negative data are very important challenges of these methods. The use of graph neural networks has recently emerged in machine learning and other related fields, and they have demonstrated superior performance for a broad range of problems. Methods In this study, a new semi-supervised learning method based on graph convolutional networks is presented using the novel constructing feature vector for each gene. In the proposed method, first, we construct three feature vectors for each gene using terms from the Gene Ontology (GO) database. Then, we train a graph convolution network on these vectors using protein–protein interaction (PPI) network data to identify disease candidate genes. Our model discovers hidden layer representations encoding in both local graph structure as well as features of nodes. This method is characterized by the simultaneous consideration of topological information of the biological network (e.g., PPI) and other sources of evidence. Finally, a validation has been done to demonstrate the efficiency of our method. Results Several experiments are performed on 16 diseases to evaluate the proposed method's performance. The experiments demonstrate that our proposed method achieves the best results, in terms of precision, the area under the ROC curve (AUCs), and F1-score values, when compared with eight state-of-the-art network and machine learning-based disease gene prioritization methods. Conclusion This study shows that the proposed semi-supervised learning method appropriately classifies and ranks candidate disease genes using a graph convolutional network and an innovative method to create three feature vectors for genes based on the molecular function, cellular component, and biological process terms from GO data.
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Affiliation(s)
- Saeid Azadifar
- Faculty of Computer Engineering, K. N. Toosi University of Technology, Tehran, Iran.
| | - Ali Ahmadi
- Faculty of Computer Engineering, K. N. Toosi University of Technology, Tehran, Iran
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Dozmorov MG, Cresswell KG, Bacanu SA, Craver C, Reimers M, Kendler KS. A method for estimating coherence of molecular mechanisms in major human disease and traits. BMC Bioinformatics 2020; 21:473. [PMID: 33087046 PMCID: PMC7579960 DOI: 10.1186/s12859-020-03821-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 10/15/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Phenotypes such as height and intelligence, are thought to be a product of the collective effects of multiple phenotype-associated genes and interactions among their protein products. High/low degree of interactions is suggestive of coherent/random molecular mechanisms, respectively. Comparing the degree of interactions may help to better understand the coherence of phenotype-specific molecular mechanisms and the potential for therapeutic intervention. However, direct comparison of the degree of interactions is difficult due to different sizes and configurations of phenotype-associated gene networks. METHODS We introduce a metric for measuring coherence of molecular-interaction networks as a slope of internal versus external distributions of the degree of interactions. The internal degree distribution is defined by interaction counts within a phenotype-specific gene network, while the external degree distribution counts interactions with other genes in the whole protein-protein interaction (PPI) network. We present a novel method for normalizing the coherence estimates, making them directly comparable. RESULTS Using STRING and BioGrid PPI databases, we compared the coherence of 116 phenotype-associated gene sets from GWAScatalog against size-matched KEGG pathways (the reference for high coherence) and random networks (the lower limit of coherence). We observed a range of coherence estimates for each category of phenotypes. Metabolic traits and diseases were the most coherent, while psychiatric disorders and intelligence-related traits were the least coherent. We demonstrate that coherence and modularity measures capture distinct network properties. CONCLUSIONS We present a general-purpose method for estimating and comparing the coherence of molecular-interaction gene networks that accounts for the network size and shape differences. Our results highlight gaps in our current knowledge of genetics and molecular mechanisms of complex phenotypes and suggest priorities for future GWASs.
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Affiliation(s)
- Mikhail G. Dozmorov
- Department of Biostatistics, Virginia Commonwealth University, Richmond, VA USA
- Department of Pathology, Virginia Commonwealth University, Richmond, VA USA
| | - Kellen G. Cresswell
- Department of Biostatistics, Virginia Commonwealth University, Richmond, VA USA
| | - Silviu-Alin Bacanu
- Virginia Institute for Psychiatric and Behavior Genetics and the Department of Psychiatry, Virginia Commonwealth University, Richmond, VA USA
| | - Carl Craver
- Philosophy-Neuroscience-Psychology Program, Washington University in St. Louis, St. Louis, MO USA
| | - Mark Reimers
- Department Physiology, Michigan State University, East Lansing, MI USA
- Department Biomedical Engineering, Michigan State University, East Lansing, MI USA
| | - Kenneth S. Kendler
- Virginia Institute for Psychiatric and Behavior Genetics and the Department of Psychiatry, Virginia Commonwealth University, Richmond, VA USA
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van Bilsen JHM, Dulos R, van Stee MF, Meima MY, Rouhani Rankouhi T, Neergaard Jacobsen L, Staudt Kvistgaard A, Garthoff JA, Knippels LMJ, Knipping K, Houben GF, Verschuren L, Meijerink M, Krishnan S. Seeking Windows of Opportunity to Shape Lifelong Immune Health: A Network-Based Strategy to Predict and Prioritize Markers of Early Life Immune Modulation. Front Immunol 2020; 11:644. [PMID: 32362896 PMCID: PMC7182036 DOI: 10.3389/fimmu.2020.00644] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/20/2020] [Indexed: 01/01/2023] Open
Abstract
A healthy immune status is strongly conditioned during early life stages. Insights into the molecular drivers of early life immune development and function are prerequisite to identify strategies to enhance immune health. Even though several starting points for targeted immune modulation have been identified and are being developed into prophylactic or therapeutic approaches, there is no regulatory guidance on how to assess the risk and benefit balance of such interventions. Six early life immune causal networks, each compromising a different time period in early life (the 1st, 2nd, 3rd trimester of gestations, birth, newborn, and infant period), were generated. Thereto information was extracted and structured from early life literature using the automated text mining and machine learning tool: Integrated Network and Dynamical Reasoning Assembler (INDRA). The tool identified relevant entities (e.g., genes/proteins/metabolites/processes/diseases), extracted causal relationships among these entities, and assembled them into early life-immune causal networks. These causal early life immune networks were denoised using GeneMania, enriched with data from the gene-disease association database DisGeNET and Gene Ontology resource tools (GO/GO-SLIM), inferred missing relationships and added expert knowledge to generate information-dense early life immune networks. Analysis of the six early life immune networks by PageRank, not only confirmed the central role of the "commonly used immune markers" (e.g., chemokines, interleukins, IFN, TNF, TGFB, and other immune activation regulators (e.g., CD55, FOXP3, GATA3, CD79A, C4BPA), but also identified less obvious candidates (e.g., CYP1A2, FOXK2, NELFCD, RENBP). Comparison of the different early life periods resulted in the prediction of 11 key early life genes overlapping all early life periods (TNF, IL6, IL10, CD4, FOXP3, IL4, NELFCD, CD79A, IL5, RENBP, and IFNG), and also genes that were only described in certain early life period(s). Concluding, here we describe a network-based approach that provides a science-based and systematical method to explore the functional development of the early life immune system through time. This systems approach aids the generation of a testing strategy for the safety and efficacy of early life immune modulation by predicting the key candidate markers during different phases of early life immune development.
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Affiliation(s)
| | - Remon Dulos
- Netherlands Organisation for Applied Scientific Research (TNO), Zeist, Netherlands
| | - Mariël F van Stee
- Netherlands Organisation for Applied Scientific Research (TNO), Zeist, Netherlands
| | - Marie Y Meima
- Netherlands Organisation for Applied Scientific Research (TNO), Zeist, Netherlands
| | | | | | | | | | - Léon M J Knippels
- Danone Nutricia Research, Utrecht, Netherlands.,Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Karen Knipping
- Danone Nutricia Research, Utrecht, Netherlands.,Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Geert F Houben
- Netherlands Organisation for Applied Scientific Research (TNO), Zeist, Netherlands
| | - Lars Verschuren
- Netherlands Organisation for Applied Scientific Research (TNO), Zeist, Netherlands
| | - Marjolein Meijerink
- Netherlands Organisation for Applied Scientific Research (TNO), Zeist, Netherlands
| | - Shaji Krishnan
- Netherlands Organisation for Applied Scientific Research (TNO), Zeist, Netherlands
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Timilsina M, Yang H, Sahay R, Rebholz-Schuhmann D. Predicting links between tumor samples and genes using 2-Layered graph based diffusion approach. BMC Bioinformatics 2019; 20:462. [PMID: 31500564 PMCID: PMC6734347 DOI: 10.1186/s12859-019-3056-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 08/26/2019] [Indexed: 12/21/2022] Open
Abstract
Background Determining the association between tumor sample and the gene is demanding because it requires a high cost for conducting genetic experiments. Thus, the discovered association between tumor sample and gene further requires clinical verification and validation. This entire mechanism is time-consuming and expensive. Due to this issue, predicting the association between tumor samples and genes remain a challenge in biomedicine. Results Here we present, a computational model based on a heat diffusion algorithm which can predict the association between tumor samples and genes. We proposed a 2-layered graph. In the first layer, we constructed a graph of tumor samples and genes where these two types of nodes are connected by “hasGene” relationship. In the second layer, the gene nodes are connected by “interaction” relationship. We applied the heat diffusion algorithms in nine different variants of genetic interaction networks extracted from STRING and BioGRID database. The heat diffusion algorithm predicted the links between tumor samples and genes with mean AUC-ROC score of 0.84. This score is obtained by using weighted genetic interactions of fusion or co-occurrence channels from the STRING database. For the unweighted genetic interaction from the BioGRID database, the algorithms predict the links with an AUC-ROC score of 0.74. Conclusions We demonstrate that the gene-gene interaction scores could improve the predictive power of the heat diffusion model to predict the links between tumor samples and genes. We showed the efficient runtime of the heat diffusion algorithm in various genetic interaction network. We statistically validated our prediction quality of the links between tumor samples and genes. Electronic supplementary material The online version of this article (10.1186/s12859-019-3056-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mohan Timilsina
- Insight Centre for Data Analytics, National University of Ireland Galway, Galway, Ireland.
| | - Haixuan Yang
- School of Mathematics Statistics and Applied Mathematics, National University of Ireland Galway, Galway, Ireland
| | - Ratnesh Sahay
- Insight Centre for Data Analytics, National University of Ireland Galway, Galway, Ireland
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Dozmorov MG. Disease classification: from phenotypic similarity to integrative genomics and beyond. Brief Bioinform 2019; 20:1769-1780. [DOI: 10.1093/bib/bby049] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/01/2018] [Indexed: 02/06/2023] Open
Abstract
Abstract
A fundamental challenge of modern biomedical research is understanding how diseases that are similar on the phenotypic level are similar on the molecular level. Integration of various genomic data sets with the traditionally used phenotypic disease similarity revealed novel genetic and molecular mechanisms and blurred the distinction between monogenic (Mendelian) and complex diseases. Network-based medicine has emerged as a complementary approach for identifying disease-causing genes, genetic mediators, disruptions in the underlying cellular functions and for drug repositioning. The recent development of machine and deep learning methods allow for leveraging real-life information about diseases to refine genetic and phenotypic disease relationships. This review describes the historical development and recent methodological advancements for studying disease classification (nosology).
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Affiliation(s)
- Mikhail G Dozmorov
- Department of Biostatistics, Virginia Commonwealth University, 830 East Main Street, Richmond, VA, USA
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8
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Tian Z, Guo M, Wang C, Xing L, Wang L, Zhang Y. Constructing an integrated gene similarity network for the identification of disease genes. J Biomed Semantics 2017; 8:32. [PMID: 29297379 PMCID: PMC5763299 DOI: 10.1186/s13326-017-0141-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Discovering novel genes that are involved human diseases is a challenging task in biomedical research. In recent years, several computational approaches have been proposed to prioritize candidate disease genes. Most of these methods are mainly based on protein-protein interaction (PPI) networks. However, since these PPI networks contain false positives and only cover less half of known human genes, their reliability and coverage are very low. Therefore, it is highly necessary to fuse multiple genomic data to construct a credible gene similarity network and then infer disease genes on the whole genomic scale. RESULTS We proposed a novel method, named RWRB, to infer causal genes of interested diseases. First, we construct five individual gene (protein) similarity networks based on multiple genomic data of human genes. Then, an integrated gene similarity network (IGSN) is reconstructed based on similarity network fusion (SNF) method. Finally, we employee the random walk with restart algorithm on the phenotype-gene bilayer network, which combines phenotype similarity network, IGSN as well as phenotype-gene association network, to prioritize candidate disease genes. We investigate the effectiveness of RWRB through leave-one-out cross-validation methods in inferring phenotype-gene relationships. Results show that RWRB is more accurate than state-of-the-art methods on most evaluation metrics. Further analysis shows that the success of RWRB is benefited from IGSN which has a wider coverage and higher reliability comparing with current PPI networks. Moreover, we conduct a comprehensive case study for Alzheimer's disease and predict some novel disease genes that supported by literature. CONCLUSIONS RWRB is an effective and reliable algorithm in prioritizing candidate disease genes on the genomic scale. Software and supplementary information are available at http://nclab.hit.edu.cn/~tianzhen/RWRB/ .
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Affiliation(s)
- Zhen Tian
- School of Computer Science and Engineering, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China
| | - Maozu Guo
- School of Computer Science and Engineering, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China
| | - Chunyu Wang
- School of Computer Science and Engineering, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China
| | - LinLin Xing
- School of Computer Science and Engineering, Harbin Institute of Technology, Harbin, 150001 People’s Republic of China
| | - Lei Wang
- Institute of Health Service and Medical Information Academy of Military Medical Sciences Beijing, Beijing, 100850 China
| | - Yin Zhang
- Institute of Health Service and Medical Information Academy of Military Medical Sciences Beijing, Beijing, 100850 China
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Abstract
Motivation: The rapid growth of diverse biological data allows us to consider interactions between a variety of objects, such as genes, chemicals, molecular signatures, diseases, pathways and environmental exposures. Often, any pair of objects—such as a gene and a disease—can be related in different ways, for example, directly via gene–disease associations or indirectly via functional annotations, chemicals and pathways. Different ways of relating these objects carry different semantic meanings. However, traditional methods disregard these semantics and thus cannot fully exploit their value in data modeling. Results: We present Medusa, an approach to detect size-k modules of objects that, taken together, appear most significant to another set of objects. Medusa operates on large-scale collections of heterogeneous datasets and explicitly distinguishes between diverse data semantics. It advances research along two dimensions: it builds on collective matrix factorization to derive different semantics, and it formulates the growing of the modules as a submodular optimization program. Medusa is flexible in choosing or combining semantic meanings and provides theoretical guarantees about detection quality. In a systematic study on 310 complex diseases, we show the effectiveness of Medusa in associating genes with diseases and detecting disease modules. We demonstrate that in predicting gene–disease associations Medusa compares favorably to methods that ignore diverse semantic meanings. We find that the utility of different semantics depends on disease categories and that, overall, Medusa recovers disease modules more accurately when combining different semantics. Availability and implementation: Source code is at http://github.com/marinkaz/medusa Contact:marinka@cs.stanford.edu, blaz.zupan@fri.uni-lj.si
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Affiliation(s)
- Marinka Zitnik
- Department of Computer Science, Stanford University, CA 94305, USA Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia 1000
| | - Blaz Zupan
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia 1000 Department of Molecular and Human Genetics, Baylor College of Medicine, TX 77030, USA
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Jiang J, Li W, Liang B, Xie R, Chen B, Huang H, Li Y, He Y, Lv J, He W, Chen L. A Novel Prioritization Method in Identifying Recurrent Venous Thromboembolism-Related Genes. PLoS One 2016; 11:e0153006. [PMID: 27050193 PMCID: PMC4822849 DOI: 10.1371/journal.pone.0153006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 03/21/2016] [Indexed: 12/13/2022] Open
Abstract
Identifying the genes involved in venous thromboembolism (VTE) recurrence is important not only for understanding the pathogenesis but also for discovering the therapeutic targets. We proposed a novel prioritization method called Function-Interaction-Pearson (FIP) by creating gene-disease similarity scores to prioritize candidate genes underling VTE. The scores were calculated by integrating and optimizing three types of resources including gene expression, gene ontology and protein-protein interaction. As a result, 124 out of top 200 prioritized candidate genes had been confirmed in literature, among which there were 34 antithrombotic drug targets. Compared with two well-known gene prioritization tools Endeavour and ToppNet, FIP was shown to have better performance. The approach provides a valuable alternative for drug targets discovery and disease therapy.
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Affiliation(s)
- Jing Jiang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
| | - Wan Li
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
| | - Binhua Liang
- National Microbology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Ruiqiang Xie
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
| | - Binbin Chen
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
| | - Hao Huang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
| | - Yiran Li
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
| | - Yuehan He
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
| | - Junjie Lv
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
| | - Weiming He
- Institute of Opto-electronics, Harbin Institute of Technology, Harbin, Hei Longjiang Province, China
- * E-mail: (LC); (WH)
| | - Lina Chen
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, Hei Longjiang Province, China, Postal code: 150081
- * E-mail: (LC); (WH)
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Yu G, Fu G, Wang J, Zhu H. Predicting Protein Function via Semantic Integration of Multiple Networks. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2016; 13:220-232. [PMID: 26800544 DOI: 10.1109/tcbb.2015.2459713] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Determining the biological functions of proteins is one of the key challenges in the post-genomic era. The rapidly accumulated large volumes of proteomic and genomic data drives to develop computational models for automatically predicting protein function in large scale. Recent approaches focus on integrating multiple heterogeneous data sources and they often get better results than methods that use single data source alone. In this paper, we investigate how to integrate multiple biological data sources with the biological knowledge, i.e., Gene Ontology (GO), for protein function prediction. We propose a method, called SimNet, to Semantically integrate multiple functional association Networks derived from heterogenous data sources. SimNet firstly utilizes GO annotations of proteins to capture the semantic similarity between proteins and introduces a semantic kernel based on the similarity. Next, SimNet constructs a composite network, obtained as a weighted summation of individual networks, and aligns the network with the kernel to get the weights assigned to individual networks. Then, it applies a network-based classifier on the composite network to predict protein function. Experiment results on heterogenous proteomic data sources of Yeast, Human, Mouse, and Fly show that, SimNet not only achieves better (or comparable) results than other related competitive approaches, but also takes much less time. The Matlab codes of SimNet are available at https://sites.google.com/site/guoxian85/simnet.
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Liu Z, Hu J. Mislocalization-related disease gene discovery using gene expression based computational protein localization prediction. Methods 2015; 93:119-27. [PMID: 26416496 DOI: 10.1016/j.ymeth.2015.09.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 09/17/2015] [Accepted: 09/21/2015] [Indexed: 01/09/2023] Open
Abstract
Protein sorting is an important mechanism for transporting proteins to their target subcellular locations after their synthesis. Mutations on genes may disrupt the well regulated protein sorting process, leading to a variety of mislocation related diseases. This paper proposes a methodology to discover such disease genes based on gene expression data and computational protein localization prediction. A kernel logistic regression based algorithm is used to successfully identify several candidate cancer genes which may cause cancers due to their mislocation within the cell. Our results also showed that compared to the gene co-expression network defined on Pearson correlation coefficients, the nonlinear Maximum Correlation Coefficients (MIC) based co-expression network give better results for subcellular localization prediction.
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Affiliation(s)
- Zhonghao Liu
- Department of Computer Science & Engineering, University of South Carolina, 301 Main Street, Columbia, SC 29208, United States
| | - Jianjun Hu
- Department of Computer Science & Engineering, University of South Carolina, 301 Main Street, Columbia, SC 29208, United States.
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ProSim: A Method for Prioritizing Disease Genes Based on Protein Proximity and Disease Similarity. BIOMED RESEARCH INTERNATIONAL 2015; 2015:213750. [PMID: 26339594 PMCID: PMC4538409 DOI: 10.1155/2015/213750] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/16/2015] [Indexed: 01/19/2023]
Abstract
Predicting disease genes for a particular genetic disease is very challenging in bioinformatics. Based on current research studies, this challenge can be tackled via network-based approaches. Furthermore, it has been highlighted that it is necessary to consider disease similarity along with the protein's proximity to disease genes in a protein-protein interaction (PPI) network in order to improve the accuracy of disease gene prioritization. In this study we propose a new algorithm called proximity disease similarity algorithm (ProSim), which takes both of the aforementioned properties into consideration, to prioritize disease genes. To illustrate the proposed algorithm, we have conducted six case studies, namely, prostate cancer, Alzheimer's disease, diabetes mellitus type 2, breast cancer, colorectal cancer, and lung cancer. We employed leave-one-out cross validation, mean enrichment, tenfold cross validation, and ROC curves to evaluate our proposed method and other existing methods. The results show that our proposed method outperforms existing methods such as PRINCE, RWR, and DADA.
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Himmelstein DS, Baranzini SE. Heterogeneous Network Edge Prediction: A Data Integration Approach to Prioritize Disease-Associated Genes. PLoS Comput Biol 2015; 11:e1004259. [PMID: 26158728 PMCID: PMC4497619 DOI: 10.1371/journal.pcbi.1004259] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/26/2015] [Indexed: 12/13/2022] Open
Abstract
The first decade of Genome Wide Association Studies (GWAS) has uncovered a wealth of disease-associated variants. Two important derivations will be the translation of this information into a multiscale understanding of pathogenic variants and leveraging existing data to increase the power of existing and future studies through prioritization. We explore edge prediction on heterogeneous networks—graphs with multiple node and edge types—for accomplishing both tasks. First we constructed a network with 18 node types—genes, diseases, tissues, pathophysiologies, and 14 MSigDB (molecular signatures database) collections—and 19 edge types from high-throughput publicly-available resources. From this network composed of 40,343 nodes and 1,608,168 edges, we extracted features that describe the topology between specific genes and diseases. Next, we trained a model from GWAS associations and predicted the probability of association between each protein-coding gene and each of 29 well-studied complex diseases. The model, which achieved 132-fold enrichment in precision at 10% recall, outperformed any individual domain, highlighting the benefit of integrative approaches. We identified pleiotropy, transcriptional signatures of perturbations, pathways, and protein interactions as influential mechanisms explaining pathogenesis. Our method successfully predicted the results (with AUROC = 0.79) from a withheld multiple sclerosis (MS) GWAS despite starting with only 13 previously associated genes. Finally, we combined our network predictions with statistical evidence of association to propose four novel MS genes, three of which (JAK2, REL, RUNX3) validated on the masked GWAS. Furthermore, our predictions provide biological support highlighting REL as the causal gene within its gene-rich locus. Users can browse all predictions online (http://het.io). Heterogeneous network edge prediction effectively prioritized genetic associations and provides a powerful new approach for data integration across multiple domains. For complex human diseases, identifying the genes harboring susceptibility variants has taken on medical importance. Disease-associated genes provide clues for elucidating disease etiology, predicting disease risk, and highlighting therapeutic targets. Here, we develop a method to predict whether a given gene and disease are associated. To capture the multitude of biological entities underlying pathogenesis, we constructed a heterogeneous network, containing multiple node and edge types. We built on a technique developed for social network analysis, which embraces disparate sources of data to make predictions from heterogeneous networks. Using the compendium of associations from genome-wide studies, we learned the influential mechanisms underlying pathogenesis. Our findings provide a novel perspective about the existence of pervasive pleiotropy across complex diseases. Furthermore, we suggest transcriptional signatures of perturbations are an underutilized resource amongst prioritization approaches. For multiple sclerosis, we demonstrated our ability to prioritize future studies and discover novel susceptibility genes. Researchers can use these predictions to increase the statistical power of their studies, to suggest the causal genes from a set of candidates, or to generate evidence-based experimental hypothesis.
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Affiliation(s)
- Daniel S. Himmelstein
- Biological & Medical Informatics, University of California, San Francisco, San Francisco, California, United States of America
| | - Sergio E. Baranzini
- Biological & Medical Informatics, University of California, San Francisco, San Francisco, California, United States of America
- Department of Neurology, University of California, San Francisco, San Francisco, California, United States of America
- Institute for Human Genetics, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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15
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Fang M, Hu X, Wang Y, Zhao J, Shen X, He T. NDRC: A Disease-Causing Genes Prioritized Method Based on Network Diffusion and Rank Concordance. IEEE Trans Nanobioscience 2015; 14:521-7. [PMID: 26080386 DOI: 10.1109/tnb.2015.2443852] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Disease-causing genes prioritization is very important to understand disease mechanisms and biomedical applications, such as design of drugs. Previous studies have shown that promising candidate genes are mostly ranked according to their relatedness to known disease genes or closely related disease genes. Therefore, a dangling gene (isolated gene) with no edges in the network can not be effectively prioritized. These approaches tend to prioritize those genes that are highly connected in the PPI network while perform poorly when they are applied to loosely connected disease genes. To address these problems, we propose a new disease-causing genes prioritization method that based on network diffusion and rank concordance (NDRC). The method is evaluated by leave-one-out cross validation on 1931 diseases in which at least one gene is known to be involved, and it is able to rank the true causal gene first in 849 of all 2542 cases. The experimental results suggest that NDRC significantly outperforms other existing methods such as RWR, VAVIEN, DADA and PRINCE on identifying loosely connected disease genes and successfully put dangling genes as potential candidate disease genes. Furthermore, we apply NDRC method to study three representative diseases, Meckel syndrome 1, Protein C deficiency and Peroxisome biogenesis disorder 1A (Zellweger). Our study has also found that certain complex disease-causing genes can be divided into several modules that are closely associated with different disease phenotype.
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Joice R, Yasuda K, Shafquat A, Morgan XC, Huttenhower C. Determining microbial products and identifying molecular targets in the human microbiome. Cell Metab 2014; 20:731-741. [PMID: 25440055 PMCID: PMC4254638 DOI: 10.1016/j.cmet.2014.10.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Human-associated microbes are the source of many bioactive microbial products (proteins and metabolites) that play key functions both in human host pathways and in microbe-microbe interactions. Culture-independent studies now provide an accelerated means of exploring novel bioactives in the human microbiome; however, intriguingly, a substantial fraction of the microbial metagenome cannot be mapped to annotated genes or isolate genomes and is thus of unknown function. Meta'omic approaches, including metagenomic sequencing, metatranscriptomics, metabolomics, and integration of multiple assay types, represent an opportunity to efficiently explore this large pool of potential therapeutics. In combination with appropriate follow-up validation, high-throughput culture-independent assays can be combined with computational approaches to identify and characterize novel and biologically interesting microbial products. Here we briefly review the state of microbial product identification and characterization and discuss possible next steps to catalog and leverage the large uncharted fraction of the microbial metagenome.
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Affiliation(s)
- Regina Joice
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Koji Yasuda
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Afrah Shafquat
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Xochitl C Morgan
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | - Curtis Huttenhower
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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Wang J, Yang J, Mao S, Chai X, Hu Y, Hou X, Tang Y, Bi C, Li X. MitProNet: A knowledgebase and analysis platform of proteome, interactome and diseases for mammalian mitochondria. PLoS One 2014; 9:e111187. [PMID: 25347823 PMCID: PMC4210245 DOI: 10.1371/journal.pone.0111187] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 09/26/2014] [Indexed: 12/18/2022] Open
Abstract
Mitochondrion plays a central role in diverse biological processes in most eukaryotes, and its dysfunctions are critically involved in a large number of diseases and the aging process. A systematic identification of mitochondrial proteomes and characterization of functional linkages among mitochondrial proteins are fundamental in understanding the mechanisms underlying biological functions and human diseases associated with mitochondria. Here we present a database MitProNet which provides a comprehensive knowledgebase for mitochondrial proteome, interactome and human diseases. First an inventory of mammalian mitochondrial proteins was compiled by widely collecting proteomic datasets, and the proteins were classified by machine learning to achieve a high-confidence list of mitochondrial proteins. The current version of MitProNet covers 1124 high-confidence proteins, and the remainders were further classified as middle- or low-confidence. An organelle-specific network of functional linkages among mitochondrial proteins was then generated by integrating genomic features encoded by a wide range of datasets including genomic context, gene expression profiles, protein-protein interactions, functional similarity and metabolic pathways. The functional-linkage network should be a valuable resource for the study of biological functions of mitochondrial proteins and human mitochondrial diseases. Furthermore, we utilized the network to predict candidate genes for mitochondrial diseases using prioritization algorithms. All proteins, functional linkages and disease candidate genes in MitProNet were annotated according to the information collected from their original sources including GO, GEO, OMIM, KEGG, MIPS, HPRD and so on. MitProNet features a user-friendly graphic visualization interface to present functional analysis of linkage networks. As an up-to-date database and analysis platform, MitProNet should be particularly helpful in comprehensive studies of complicated biological mechanisms underlying mitochondrial functions and human mitochondrial diseases. MitProNet is freely accessible at http://bio.scu.edu.cn:8085/MitProNet.
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Affiliation(s)
- Jiabin Wang
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
| | - Jian Yang
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
| | - Song Mao
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
| | - Xiaoqiang Chai
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
| | - Yuling Hu
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
| | - Xugang Hou
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
| | - Yiheng Tang
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
| | - Cheng Bi
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
| | - Xiao Li
- College of Life Sciences, Sichuan University, Ministry of Education Key Laboratory for Bio-resource and Eco-environment, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Chengdu, People’s Republic of China
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Martin F, Sewer A, Talikka M, Xiang Y, Hoeng J, Peitsch MC. Quantification of biological network perturbations for mechanistic insight and diagnostics using two-layer causal models. BMC Bioinformatics 2014; 15:238. [PMID: 25015298 PMCID: PMC4227138 DOI: 10.1186/1471-2105-15-238] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 06/26/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND High-throughput measurement technologies such as microarrays provide complex datasets reflecting mechanisms perturbed in an experiment, typically a treatment vs. control design. Analysis of these information rich data can be guided based on a priori knowledge, such as networks or set of related proteins or genes. Among those, cause-and-effect network models are becoming increasingly popular and more than eighty such models, describing processes involved in cell proliferation, cell fate, cell stress, and inflammation have already been published. A meaningful systems toxicology approach to study the response of a cell system, or organism, exposed to bio-active substances requires a quantitative measure of dose-response at network level, to go beyond the differential expression of single genes. RESULTS We developed a method that quantifies network response in an interpretable manner. It fully exploits the (signed graph) structure of cause-and-effect networks models to integrate and mine transcriptomics measurements. The presented approach also enables the extraction of network-based signatures for predicting a phenotype of interest. The obtained signatures are coherent with the underlying network perturbation and can lead to more robust predictions across independent studies. The value of the various components of our mathematically coherent approach is substantiated using several in vivo and in vitro transcriptomics datasets. As a proof-of-principle, our methodology was applied to unravel mechanisms related to the efficacy of a specific anti-inflammatory drug in patients suffering from ulcerative colitis. A plausible mechanistic explanation of the unequal efficacy of the drug is provided. Moreover, by utilizing the underlying mechanisms, an accurate and robust network-based diagnosis was built to predict the response to the treatment. CONCLUSION The presented framework efficiently integrates transcriptomics data and "cause and effect" network models to enable a mathematically coherent framework from quantitative impact assessment and data interpretation to patient stratification for diagnosis purposes.
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Affiliation(s)
- Florian Martin
- Philip Morris International, R&D, Biological Systems Research, Quai Jeanrenaud 5, 2000 Neuchatel, Switzerland.
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Valentini G, Paccanaro A, Caniza H, Romero AE, Re M. An extensive analysis of disease-gene associations using network integration and fast kernel-based gene prioritization methods. Artif Intell Med 2014; 61:63-78. [PMID: 24726035 PMCID: PMC4070077 DOI: 10.1016/j.artmed.2014.03.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 03/05/2014] [Accepted: 03/10/2014] [Indexed: 02/07/2023]
Abstract
OBJECTIVE In the context of "network medicine", gene prioritization methods represent one of the main tools to discover candidate disease genes by exploiting the large amount of data covering different types of functional relationships between genes. Several works proposed to integrate multiple sources of data to improve disease gene prioritization, but to our knowledge no systematic studies focused on the quantitative evaluation of the impact of network integration on gene prioritization. In this paper, we aim at providing an extensive analysis of gene-disease associations not limited to genetic disorders, and a systematic comparison of different network integration methods for gene prioritization. MATERIALS AND METHODS We collected nine different functional networks representing different functional relationships between genes, and we combined them through both unweighted and weighted network integration methods. We then prioritized genes with respect to each of the considered 708 medical subject headings (MeSH) diseases by applying classical guilt-by-association, random walk and random walk with restart algorithms, and the recently proposed kernelized score functions. RESULTS The results obtained with classical random walk algorithms and the best single network achieved an average area under the curve (AUC) across the 708 MeSH diseases of about 0.82, while kernelized score functions and network integration boosted the average AUC to about 0.89. Weighted integration, by exploiting the different "informativeness" embedded in different functional networks, outperforms unweighted integration at 0.01 significance level, according to the Wilcoxon signed rank sum test. For each MeSH disease we provide the top-ranked unannotated candidate genes, available for further bio-medical investigation. CONCLUSIONS Network integration is necessary to boost the performances of gene prioritization methods. Moreover the methods based on kernelized score functions can further enhance disease gene ranking results, by adopting both local and global learning strategies, able to exploit the overall topology of the network.
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Affiliation(s)
- Giorgio Valentini
- AnacletoLab - Dipartimento di Informatica, Università degli Studi di Milano, via Comelico 39/41, 20135 Milano, Italy.
| | - Alberto Paccanaro
- Department of Computer Science and Centre for Systems and Synthetic Biology, Royal Holloway, University of London, Egham TW20 0EX, UK
| | - Horacio Caniza
- Department of Computer Science and Centre for Systems and Synthetic Biology, Royal Holloway, University of London, Egham TW20 0EX, UK
| | - Alfonso E Romero
- Department of Computer Science and Centre for Systems and Synthetic Biology, Royal Holloway, University of London, Egham TW20 0EX, UK
| | - Matteo Re
- AnacletoLab - Dipartimento di Informatica, Università degli Studi di Milano, via Comelico 39/41, 20135 Milano, Italy
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20
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Staunton L, Clancy T, Tonry C, Hernández B, Ademowo S, Dharsee M, Evans K, Parnell AC, Watson RW, Tasken KA, Pennington SR. Protein Quantification by MRM for Biomarker Validation. QUANTITATIVE PROTEOMICS 2014. [DOI: 10.1039/9781782626985-00277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In this chapter we describe how mass spectrometry-based quantitative protein measurements by multiple reaction monitoring (MRM) have opened up the opportunity for the assembly of large panels of candidate protein biomarkers that can be simultaneously validated in large clinical cohorts to identify diagnostic protein biomarker signatures. We outline a workflow in which candidate protein biomarker panels are initially assembled from multiple diverse sources of discovery data, including proteomics and transcriptomics experiments, as well as from candidates found in the literature. Subsequently, the individual candidates in these large panels may be prioritised by application of a range of bioinformatics tools to generate a refined panel for which MRM assays may be developed. We describe a process for MRM assay design and implementation, and illustrate how the data generated from these multiplexed MRM measurements of prioritised candidates may be subjected to a range of statistical tools to create robust biomarker signatures for further clinical validation in large patient sample cohorts. Through this overall approach MRM has the potential to not only support individual biomarker validation but also facilitate the development of clinically useful protein biomarker signatures.
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Affiliation(s)
- L. Staunton
- UCD Conway Institute, School of Medicine and Medical Science, University College Dublin Dublin 4 Ireland
| | - T. Clancy
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital Norway
| | - C. Tonry
- UCD Conway Institute, School of Medicine and Medical Science, University College Dublin Dublin 4 Ireland
| | - B. Hernández
- UCD Conway Institute, School of Medicine and Medical Science, University College Dublin Dublin 4 Ireland
| | - S. Ademowo
- UCD Conway Institute, School of Medicine and Medical Science, University College Dublin Dublin 4 Ireland
| | - M. Dharsee
- Ontario Cancer Biomarker Network Toronto Ontario M5A 2K3 Canada
| | - K. Evans
- Ontario Cancer Biomarker Network Toronto Ontario M5A 2K3 Canada
| | - A. C. Parnell
- School of Mathematical Sciences, University College Dublin Dublin 4 Ireland
| | - R. W. Watson
- UCD Conway Institute, School of Medicine and Medical Science, University College Dublin Dublin 4 Ireland
| | - K. A. Tasken
- Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital Norway
| | - S. R. Pennington
- UCD Conway Institute, School of Medicine and Medical Science, University College Dublin Dublin 4 Ireland
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Abstract
High throughput technologies have been applied to investigate the underlying mechanisms of complex diseases, identify disease-associations and help to improve treatment. However it is challenging to derive biological insight from conventional single gene based analysis of "omics" data from high throughput experiments due to sample and patient heterogeneity. To address these challenges, many novel pathway and network based approaches were developed to integrate various "omics" data, such as gene expression, copy number alteration, Genome Wide Association Studies, and interaction data. This review will cover recent methodological developments in pathway analysis for the detection of dysregulated interactions and disease-associated subnetworks, prioritization of candidate disease genes, and disease classifications. For each application, we will also discuss the associated challenges and potential future directions.
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Cun Y, Fröhlich H. Network and data integration for biomarker signature discovery via network smoothed T-statistics. PLoS One 2013; 8:e73074. [PMID: 24019896 PMCID: PMC3760887 DOI: 10.1371/journal.pone.0073074] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 07/16/2013] [Indexed: 01/01/2023] Open
Abstract
Predictive, stable and interpretable gene signatures are generally seen as an important step towards a better personalized medicine. During the last decade various methods have been proposed for that purpose. However, one important obstacle for making gene signatures a standard tool in clinics is the typical low reproducibility of signatures combined with the difficulty to achieve a clear biological interpretation. For that purpose in the last years there has been a growing interest in approaches that try to integrate information from molecular interaction networks. We here propose a technique that integrates network information as well as different kinds of experimental data (here exemplified by mRNA and miRNA expression) into one classifier. This is done by smoothing t-statistics of individual genes or miRNAs over the structure of a combined protein-protein interaction (PPI) and miRNA-target gene network. A permutation test is conducted to select features in a highly consistent manner, and subsequently a Support Vector Machine (SVM) classifier is trained. Compared to several other competing methods our algorithm reveals an overall better prediction performance for early versus late disease relapse and a higher signature stability. Moreover, obtained gene lists can be clearly associated to biological knowledge, such as known disease genes and KEGG pathways. We demonstrate that our data integration strategy can improve classification performance compared to using a single data source only. Our method, called stSVM, is available in R-package netClass on CRAN (http://cran.r-project.org).
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Affiliation(s)
- Yupeng Cun
- Algorithmic Bioinformatics, Bonn-Aachen International Center for IT, Bonn, Germany
| | - Holger Fröhlich
- Algorithmic Bioinformatics, Bonn-Aachen International Center for IT, Bonn, Germany
- * E-mail:
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