1
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Wu H, Song C, Ge Y, Ge T. Link Prediction on Complex Networks: An Experimental Survey. DATA SCIENCE AND ENGINEERING 2022; 7:253-278. [PMID: 35754861 PMCID: PMC9211798 DOI: 10.1007/s41019-022-00188-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/31/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Complex networks have been used widely to model a large number of relationships. The outbreak of COVID-19 has had a huge impact on various complex networks in the real world, for example global trade networks, air transport networks, and even social networks, known as racial equality issues caused by the spread of the epidemic. Link prediction plays an important role in complex network analysis in that it can find missing links or predict the links which will arise in the future in the network by analyzing the existing network structures. Therefore, it is extremely important to study the link prediction problem on complex networks. There are a variety of techniques for link prediction based on the topology of the network and the properties of entities. In this work, a new taxonomy is proposed to divide the link prediction methods into five categories and a comprehensive overview of these methods is provided. The network embedding-based methods, especially graph neural network-based methods, which have attracted increasing attention in recent years, have been creatively investigated as well. Moreover, we analyze thirty-six datasets and divide them into seven types of networks according to their topological features shown in real networks and perform comprehensive experiments on these networks. We further analyze the results of experiments in detail, aiming to discover the most suitable approach for each kind of network.
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Affiliation(s)
- Haixia Wu
- College of Computer Science, Tianjin Key Laboratory of Network and Data Security Technology, Nankai University, Tianjin, China
| | - Chunyao Song
- College of Computer Science, Tianjin Key Laboratory of Network and Data Security Technology, Nankai University, Tianjin, China
| | - Yao Ge
- College of Computer Science, Tianjin Key Laboratory of Network and Data Security Technology, Nankai University, Tianjin, China
| | - Tingjian Ge
- University of Massachusetts Lowell, Massachusetts, United States
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2
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Estrada E. Fractional diffusion on the human proteome as an alternative to the multi-organ damage of SARS-CoV-2. CHAOS (WOODBURY, N.Y.) 2020; 30:081104. [PMID: 32872802 PMCID: PMC7585451 DOI: 10.1063/5.0015626] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 07/15/2020] [Indexed: 05/16/2023]
Abstract
The coronavirus 2019 (COVID-19) respiratory disease is caused by the novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), which uses the enzyme ACE2 to enter human cells. This disease is characterized by important damage at a multi-organ level, partially due to the abundant expression of ACE2 in practically all human tissues. However, not every organ in which ACE2 is abundant is affected by SARS-CoV-2, which suggests the existence of other multi-organ routes for transmitting the perturbations produced by the virus. We consider here diffusive processes through the protein-protein interaction (PPI) network of proteins targeted by SARS-CoV-2 as an alternative route. We found a subdiffusive regime that allows the propagation of virus perturbations through the PPI network at a significant rate. By following the main subdiffusive routes across the PPI network, we identify proteins mainly expressed in the heart, cerebral cortex, thymus, testis, lymph node, kidney, among others of the organs reported to be affected by COVID-19.
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Affiliation(s)
- Ernesto Estrada
- Instituto Universitario de Matemáticas y Aplicaciones, Universidad de Zaragoza, 50009 Zaragoza, Spain and ARAID Foundation, Government of Aragón, 50018 Zaragoza, Spain
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3
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Devkota P, Danzi MC, Lemmon VP, Bixby JL, Wuchty S. Computational Identification of Kinases That Control Axon Growth in Mouse. SLAS DISCOVERY 2020; 25:792-800. [PMID: 32613890 DOI: 10.1177/2472555220930697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The determination of signaling pathways and transcriptional networks that control various biological processes is a major challenge from both basic science and translational medicine perspectives. Because such analysis can point to critical disease driver nodes to target for therapeutic purposes, we combined data from phenotypic screening experiments and gene expression studies of mouse neurons to determine information flow through a molecular interaction network using a network propagation approach. We hypothesized that differences in information flow between control and injured conditions prioritize relevant driver nodes that cause this state change. Identifying paths likely taken from potential source nodes to a set of transcription factors (TFs), called sinks, we found that kinases are enriched among source genes sending significantly different amounts of information to TFs in an axonal injury model. Additionally, TFs found to be differentially active during axon growth were enriched in the set of sink genes that received significantly altered amounts of information from source genes. Notably, such enrichment levels hold even when restricting the set of source genes to only those kinases observed to support or hamper neurite growth. That way, we found a set of 71 source genes that send significantly different levels of information to axon growth-relevant TFs. We analyzed their information flow changes in response to axonal injury and their influences on TFs predicted to facilitate or antagonize axon growth. Finally, we drew a network diagram of the interactions and changes in information flow between these source genes and their axon growth-relevant sink TFs.
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Affiliation(s)
- Prajwal Devkota
- Department of Computer Science, University of Miami, Miami, FL, USA
| | - Matt C Danzi
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Vance P Lemmon
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA.,Miami Institute of Data Science and Computing, University of Miami, Miami, FL, USA.,Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.,Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA.,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
| | - John L Bixby
- Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA.,Miami Institute of Data Science and Computing, University of Miami, Miami, FL, USA.,Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.,Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA.,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Stefan Wuchty
- Department of Computer Science, University of Miami, Miami, FL, USA.,Miami Institute of Data Science and Computing, University of Miami, Miami, FL, USA.,Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA.,Department of Biology, University of Miami, Miami, FL, USA
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4
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Kennedy SA, Jarboui MA, Srihari S, Raso C, Bryan K, Dernayka L, Charitou T, Bernal-Llinares M, Herrera-Montavez C, Krstic A, Matallanas D, Kotlyar M, Jurisica I, Curak J, Wong V, Stagljar I, LeBihan T, Imrie L, Pillai P, Lynn MA, Fasterius E, Al-Khalili Szigyarto C, Breen J, Kiel C, Serrano L, Rauch N, Rukhlenko O, Kholodenko BN, Iglesias-Martinez LF, Ryan CJ, Pilkington R, Cammareri P, Sansom O, Shave S, Auer M, Horn N, Klose F, Ueffing M, Boldt K, Lynn DJ, Kolch W. Extensive rewiring of the EGFR network in colorectal cancer cells expressing transforming levels of KRAS G13D. Nat Commun 2020; 11:499. [PMID: 31980649 PMCID: PMC6981206 DOI: 10.1038/s41467-019-14224-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 12/05/2019] [Indexed: 02/07/2023] Open
Abstract
Protein-protein-interaction networks (PPINs) organize fundamental biological processes, but how oncogenic mutations impact these interactions and their functions at a network-level scale is poorly understood. Here, we analyze how a common oncogenic KRAS mutation (KRASG13D) affects PPIN structure and function of the Epidermal Growth Factor Receptor (EGFR) network in colorectal cancer (CRC) cells. Mapping >6000 PPIs shows that this network is extensively rewired in cells expressing transforming levels of KRASG13D (mtKRAS). The factors driving PPIN rewiring are multifactorial including changes in protein expression and phosphorylation. Mathematical modelling also suggests that the binding dynamics of low and high affinity KRAS interactors contribute to rewiring. PPIN rewiring substantially alters the composition of protein complexes, signal flow, transcriptional regulation, and cellular phenotype. These changes are validated by targeted and global experimental analysis. Importantly, genetic alterations in the most extensively rewired PPIN nodes occur frequently in CRC and are prognostic of poor patient outcomes.
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Affiliation(s)
- Susan A Kennedy
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
| | - Mohamed-Ali Jarboui
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Siemens Imaging Center, University of Tübingen, Tübingen, Germany
| | - Sriganesh Srihari
- EMBL Australia Group, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
- QIMR-Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia
| | - Cinzia Raso
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
| | - Kenneth Bryan
- EMBL Australia Group, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Layal Dernayka
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Theodosia Charitou
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
- EMBL Australia Group, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Manuel Bernal-Llinares
- EMBL Australia Group, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | | | | | - David Matallanas
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
| | - Max Kotlyar
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Igor Jurisica
- Krembil Research Institute, University Health Network, Toronto, Canada
- Departments of Medical Biophysics and Computer Science, University of Toronto, Toronto, Canada
- Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Jasna Curak
- Donnelly Centre, University of Toronto, Toronto, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Victoria Wong
- Donnelly Centre, University of Toronto, Toronto, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Igor Stagljar
- Donnelly Centre, University of Toronto, Toronto, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Mediterranean Institute for Life Sciences, Split, Croatia
| | - Thierry LeBihan
- Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
| | - Lisa Imrie
- Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
| | - Priyanka Pillai
- EMBL Australia Group, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Miriam A Lynn
- EMBL Australia Group, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia
| | - Erik Fasterius
- School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Cristina Al-Khalili Szigyarto
- School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
- Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - James Breen
- School of Biological Sciences, University of Adelaide Bioinformatics Hub, Adelaide, SA, Australia
- Computational & Systems Biology Program, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Christina Kiel
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
- Conway Institute, University College Dublin, Dublin, Ireland
| | - Luis Serrano
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Nora Rauch
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
| | | | - Boris N Kholodenko
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
- Conway Institute, University College Dublin, Dublin, Ireland
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Colm J Ryan
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
- School of Computer Science, University College Dublin, Dublin, Ireland
| | - Ruth Pilkington
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
| | | | - Owen Sansom
- Cancer Research UK Beatson Institute, Glasgow, UK
- Institute of Cancer Studies, Glasgow University, Glasgow, UK
| | - Steven Shave
- School of Biological Sciences and School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Manfred Auer
- School of Biological Sciences and School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Nicola Horn
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Franziska Klose
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Karsten Boldt
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
| | - David J Lynn
- EMBL Australia Group, South Australian Health and Medical Research Institute, Adelaide, SA, 5000, Australia.
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, 5042, Australia.
| | - Walter Kolch
- Systems Biology Ireland, University College Dublin, Dublin, Ireland.
- Conway Institute, University College Dublin, Dublin, Ireland.
- School of Medicine, University College Dublin, Dublin, Ireland.
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5
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Alves G, Yu YK. Robust Accurate Identification and Biomass Estimates of Microorganisms via Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:85-102. [PMID: 32881514 PMCID: PMC10501333 DOI: 10.1021/jasms.9b00035] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Rapid and accurate identification of microorganisms and estimation of their biomasses are of extreme importance to public health. Mass spectrometry has become an important technique for these purposes. Previously we published a workflow named Microorganism Classification and Identification (MiCId v.12.26.2017) that was shown to perform no worse than other workflows. This manuscript presents MiCId v.12.13.2018 that, in comparison with the earlier version v.12.26.2017, allows for biomass estimates, provides more accurate microorganism identifications (better controls the number of false positives), and is robust against database size increase. This significant advance is made possible by several new ingredients introduced: first, we apply a modified expectation-maximization method to compute for each taxon considered a prior probability, which can be used for biomass estimate; second, we introduce a new concept called ownership, through which the participation ratio is computed and use it as the number of taxa to be kept within a cluster of closely related taxa; third, based on confidently identified peptides, we calculate for each taxon its degree of independence from the rest of taxa considered to determine whether or not to split this taxon off the cluster. Using 270 data files, each containing a large number of MS/MS spectra, we show that, in comparison with v.12.26.2017, version v.12.13.2018 yields superior retrieval results. We also show that MiCId v.12.13.2018 can estimate species biomass reasonably well. The new MiCId v.12.13.2018, designed to run in Linux environment, is freely available for download at https://www.ncbi.nlm.nih.gov/CBBresearch/Yu/downloads.html.
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Affiliation(s)
- Gelio Alves
- National Center for Biotehnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, United States
| | - Yi-Kuo Yu
- National Center for Biotehnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, United States
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6
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Cheng L, Jiang Y, Ju H, Sun J, Peng J, Zhou M, Hu Y. InfAcrOnt: calculating cross-ontology term similarities using information flow by a random walk. BMC Genomics 2018; 19:919. [PMID: 29363423 PMCID: PMC5780854 DOI: 10.1186/s12864-017-4338-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Background Since the establishment of the first biomedical ontology Gene Ontology (GO), the number of biomedical ontology has increased dramatically. Nowadays over 300 ontologies have been built including extensively used Disease Ontology (DO) and Human Phenotype Ontology (HPO). Because of the advantage of identifying novel relationships between terms, calculating similarity between ontology terms is one of the major tasks in this research area. Though similarities between terms within each ontology have been studied with in silico methods, term similarities across different ontologies were not investigated as deeply. The latest method took advantage of gene functional interaction network (GFIN) to explore such inter-ontology similarities of terms. However, it only used gene interactions and failed to make full use of the connectivity among gene nodes of the network. In addition, all existent methods are particularly designed for GO and their performances on the extended ontology community remain unknown. Results We proposed a method InfAcrOnt to infer similarities between terms across ontologies utilizing the entire GFIN. InfAcrOnt builds a term-gene-gene network which comprised ontology annotations and GFIN, and acquires similarities between terms across ontologies through modeling the information flow within the network by random walk. In our benchmark experiments on sub-ontologies of GO, InfAcrOnt achieves a high average area under the receiver operating characteristic curve (AUC) (0.9322 and 0.9309) and low standard deviations (1.8746e-6 and 3.0977e-6) in both human and yeast benchmark datasets exhibiting superior performance. Meanwhile, comparisons of InfAcrOnt results and prior knowledge on pair-wise DO-HPO terms and pair-wise DO-GO terms show high correlations. Conclusions The experiment results show that InfAcrOnt significantly improves the performance of inferring similarities between terms across ontologies in benchmark set. Electronic supplementary material The online version of this article (10.1186/s12864-017-4338-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Liang Cheng
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, People's Republic of China
| | - Yue Jiang
- Hospital for Sick Children, Toronto, M5G 1X8, Canada
| | - Hong Ju
- Department of Information Engineering, Heilongjiang Biological Science and Technology Career Academy, Harbin, 150081, People's Republic of China
| | - Jie Sun
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, People's Republic of China
| | - Jiajie Peng
- School of Computer Science, Northwestern Polytechnical University, Xian, 710072, People's Republic of China
| | - Meng Zhou
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, 150081, People's Republic of China.
| | - Yang Hu
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, 150088, People's Republic of China.
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7
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Gibbs DL, Shmulevich I. Solving the influence maximization problem reveals regulatory organization of the yeast cell cycle. PLoS Comput Biol 2017; 13:e1005591. [PMID: 28628618 PMCID: PMC5495484 DOI: 10.1371/journal.pcbi.1005591] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 07/03/2017] [Accepted: 05/24/2017] [Indexed: 02/07/2023] Open
Abstract
The Influence Maximization Problem (IMP) aims to discover the set of nodes with the greatest influence on network dynamics. The problem has previously been applied in epidemiology and social network analysis. Here, we demonstrate the application to cell cycle regulatory network analysis for Saccharomyces cerevisiae. Fundamentally, gene regulation is linked to the flow of information. Therefore, our implementation of the IMP was framed as an information theoretic problem using network diffusion. Utilizing more than 26,000 regulatory edges from YeastMine, gene expression dynamics were encoded as edge weights using time lagged transfer entropy, a method for quantifying information transfer between variables. By picking a set of source nodes, a diffusion process covers a portion of the network. The size of the network cover relates to the influence of the source nodes. The set of nodes that maximizes influence is the solution to the IMP. By solving the IMP over different numbers of source nodes, an influence ranking on genes was produced. The influence ranking was compared to other metrics of network centrality. Although the top genes from each centrality ranking contained well-known cell cycle regulators, there was little agreement and no clear winner. However, it was found that influential genes tend to directly regulate or sit upstream of genes ranked by other centrality measures. The influential nodes act as critical sources of information flow, potentially having a large impact on the state of the network. Biological events that affect influential nodes and thereby affect information flow could have a strong effect on network dynamics, potentially leading to disease. Code and data can be found at: https://github.com/gibbsdavidl/miergolf.
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Affiliation(s)
- David L. Gibbs
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - Ilya Shmulevich
- Institute for Systems Biology, Seattle, Washington, United States of America
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8
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Suo T, Liu J, Chen X, Yu H, Wang T, Li C, Wang Y, Wang C, Li Z. Combining Chemical Profiling and Network Analysis to Investigate the Pharmacology of Complex Prescriptions in Traditional Chinese Medicine. Sci Rep 2017; 7:40529. [PMID: 28084407 PMCID: PMC5233960 DOI: 10.1038/srep40529] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 12/07/2016] [Indexed: 12/28/2022] Open
Abstract
We present a paradigm, combining chemical profiling, absorbed components detection in plasma and network analysis, for investigating the pharmacology of combination drugs and complex formulae. On the one hand, the composition of the formula is investigated comprehensively via mass spectrometry analysis, followed by pharmacological studies of the fractions as well as the plasma concentration testing for the ingredients. On the other hand, both the candidate target proteins and the effective ingredients of the formula are predicted via analyzing the corresponding networks. The most probable active compounds can then be identified by combining the experimental results with the network analysis. In order to illustrate the performance of the paradigm, we apply it to the Danggui-Jianzhong formula (DJF) from traditional Chinese medicine (TCM) and predict 4 probably active ingredients, 3 of which are verified experimentally to display anti-platelet activity, i.e., (Z)-Ligustilide, Licochalcone A and Pentagalloylglucose. Moreover, the 3-compound formulae composed of these 3 chemicals show better anti-platelet activity than DJF. In addition, the paradigm predicts the association between these 3 compounds and COX-1, and our experimental validation further shows that such association comes from the inhibitory effects of the compounds on the activity of COX-1.
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Affiliation(s)
- Tongchuan Suo
- College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
| | - Jinping Liu
- Tianjin Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
| | - Xi Chen
- College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
| | - Hua Yu
- Tianjin Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
| | - Tenglong Wang
- Tianjin Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
| | - Congcong Li
- Tianjin Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
| | - Yuefei Wang
- Tianjin Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
| | - Chunhua Wang
- Tianjin Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
| | - Zheng Li
- College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China.,Tianjin Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, PR China
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9
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Abstract
Cancer is now increasingly studied from the perspective of dysregulated pathways, rather than as a disease resulting from mutations of individual genes. A pathway-centric view acknowledges the heterogeneity between genomic profiles from different cancer patients while assuming that the mutated genes are likely to belong to the same pathway and cause similar disease phenotypes. Indeed, network-centric approaches have proven to be helpful for finding genotypic causes of diseases, classifying disease subtypes, and identifying drug targets. In this review, we discuss how networks can be used to help understand patient-to-patient variations and how one can leverage this variability to elucidate interactions between cancer drivers.
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Affiliation(s)
- Yoo-Ah Kim
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dong-Yeon Cho
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Teresa M. Przytycka
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
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10
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Hamaneh MB, Haber J, Yu YK. Analytical solution and scaling of fluctuations in complex networks traversed by damped, interacting random walkers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:052803. [PMID: 26651740 PMCID: PMC5873644 DOI: 10.1103/physreve.92.052803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Indexed: 06/05/2023]
Abstract
A general model for random walks (RWs) on networks is proposed. It incorporates damping and time-dependent links, and it includes standard (undamped, noninteracting) RWs (SRWs), coalescing RWs, and coalescing-branching RWs as special cases. The exact, time-dependent solutions for the average numbers of visits (w) to nodes and their fluctuations (σ2) are given, and the long-term σ-w relation is studied. Although σ ∝ w(1/2) for SRWs, this power law can be fragile when coalescing-branching interaction is present. Damping, however, often strengthens it but with an exponent generally different from 1/2.
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11
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Ghosh S, Kumar GV, Basu A, Banerjee A. Graph theoretic network analysis reveals protein pathways underlying cell death following neurotropic viral infection. Sci Rep 2015; 5:14438. [PMID: 26404759 PMCID: PMC4585883 DOI: 10.1038/srep14438] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 08/28/2015] [Indexed: 12/17/2022] Open
Abstract
Complex protein networks underlie any cellular function. Certain proteins play a pivotal role in many network configurations, disruption of whose expression proves fatal to the cell. An efficient method to tease out such key proteins in a network is still unavailable. Here, we used graph-theoretic measures on protein-protein interaction data (interactome) to extract biophysically relevant information about individual protein regulation and network properties such as formation of function specific modules (sub-networks) of proteins. We took 5 major proteins that are involved in neuronal apoptosis post Chandipura Virus (CHPV) infection as seed proteins in a database to create a meta-network of immediately interacting proteins (1st order network). Graph theoretic measures were employed to rank the proteins in terms of their connectivity and the degree upto which they can be organized into smaller modules (hubs). We repeated the analysis on 2nd order interactome that includes proteins connected directly with proteins of 1st order. FADD and Casp-3 were connected maximally to other proteins in both analyses, thus indicating their importance in neuronal apoptosis. Thus, our analysis provides a blueprint for the detection and validation of protein networks disrupted by viral infections.
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Affiliation(s)
- Sourish Ghosh
- National Brain Research Centre, NH 8, Manesar, Gurgaon -122051, Haryana, India
| | - G Vinodh Kumar
- National Brain Research Centre, NH 8, Manesar, Gurgaon -122051, Haryana, India
| | - Anirban Basu
- National Brain Research Centre, NH 8, Manesar, Gurgaon -122051, Haryana, India
| | - Arpan Banerjee
- National Brain Research Centre, NH 8, Manesar, Gurgaon -122051, Haryana, India
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12
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Hamaneh MB, Yu YK. DeCoaD: determining correlations among diseases using protein interaction networks. BMC Res Notes 2015; 8:226. [PMID: 26047952 PMCID: PMC4467632 DOI: 10.1186/s13104-015-1211-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 05/22/2015] [Indexed: 11/23/2022] Open
Abstract
Background Disease–disease similarities can be investigated from multiple perspectives. Identifying similar diseases based on the underlying biomolecular interactions can be especially useful, because it may shed light on the common causes of the diseases and therefore may provide clues for possible treatments. Here we introduce DeCoaD, a web-based program that uses a novel method to assign pair-wise similarity scores, called correlations, to genetic diseases. Findings DeCoaD uses a random walk to model the flow of information in a network within which nodes are either diseases or proteins and links signify either protein–protein interactions or disease–protein associations. For each protein node, the total number of visits by the random walker is called the weight of that node. Using a disease as both the starting and the terminating points of the random walks, a corresponding vector, whose elements are the weights associated with the proteins, can be constructed. The similarity between two diseases is defined as the cosine of the angle between their associated vectors. For a user-specified disease, DeCoaD outputs a list of similar diseases (with their corresponding correlations), and a graphical representation of the disease families that they belong to. Based on a probabilistic clustering algorithm, DeCoaD also outputs the clusters that the disease of interest is a member of, and the corresponding probabilities. The program also provides an interface to run enrichment analysis for the given disease or for any of the clusters that contains it. Conclusions DeCoaD uses a novel algorithm to suggest non-trivial similarities between diseases with known gene associations, and also clusters the diseases based on their similarity scores. DeCoaD is available at http://www.ncbi.nlm.nih.gov/CBBresearch/Yu/mn/DeCoaD/.
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Affiliation(s)
- Mehdi B Hamaneh
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 8600 Rockville Pike, Bethesda, MD, 20894, USA.
| | - Yi-Kuo Yu
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, 8600 Rockville Pike, Bethesda, MD, 20894, USA.
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Hamaneh MB, Yu YK. Relating diseases by integrating gene associations and information flow through protein interaction network. PLoS One 2014; 9:e110936. [PMID: 25360770 PMCID: PMC4216010 DOI: 10.1371/journal.pone.0110936] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 09/27/2014] [Indexed: 12/31/2022] Open
Abstract
Identifying similar diseases could potentially provide deeper understanding of their underlying causes, and may even hint at possible treatments. For this purpose, it is necessary to have a similarity measure that reflects the underpinning molecular interactions and biological pathways. We have thus devised a network-based measure that can partially fulfill this goal. Our method assigns weights to all proteins (and consequently their encoding genes) by using information flow from a disease to the protein interaction network and back. Similarity between two diseases is then defined as the cosine of the angle between their corresponding weight vectors. The proposed method also provides a way to suggest disease-pathway associations by using the weights assigned to the genes to perform enrichment analysis for each disease. By calculating pairwise similarities between 2534 diseases, we show that our disease similarity measure is strongly correlated with the probability of finding the diseases in the same disease family and, more importantly, sharing biological pathways. We have also compared our results to those of MimMiner, a text-mining method that assigns pairwise similarity scores to diseases. We find the results of the two methods to be complementary. It is also shown that clustering diseases based on their similarities and performing enrichment analysis for the cluster centers significantly increases the term association rate, suggesting that the cluster centers are better representatives for biological pathways than the diseases themselves. This lends support to the view that our similarity measure is a good indicator of relatedness of biological processes involved in causing the diseases. Although not needed for understanding this paper, the raw results are available for download for further study at ftp://ftp.ncbi.nlm.nih.gov/pub/qmbpmn/DiseaseRelations/.
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Affiliation(s)
- Mehdi Bagheri Hamaneh
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States of America
| | - Yi-Kuo Yu
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States of America
- * E-mail:
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Stojmirović A, Yu YK. Building a hierarchical organization of protein complexes out of protein association data. PLoS One 2014; 9:e100098. [PMID: 24978199 PMCID: PMC4076247 DOI: 10.1371/journal.pone.0100098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 05/22/2014] [Indexed: 11/18/2022] Open
Abstract
Organizing experimentally determined protein associations as a hierarchy can be a good approach to elucidating the content of protein complexes and the modularity of subcomplexes. Several challenges exist. First, intrinsically sticky proteins, such as chaperones, are often falsely assigned to many functionally unrelated complexes. Second, the reported collections of proteins may not be true "complexes" in the sense that they bind together and perform a joint cellular function. Third, due to imperfect sensitivity of protein detection methods, both false positive and false negative assignments of a protein to complexes may occur. We mitigate the first issue by down-weighting sticky proteins by their occurrence frequencies. We approach the other two problems by merging nearly identical complexes and by constructing a directed acyclic graph (DAG) based on the relationship of partial inclusion. The constructed DAG, within which smaller complexes form parts of the larger, can reveal how different complexes are joined. By merging almost identical complexes one can deemphasize the influence of false positives, while allowing false negatives to be rescued by other nearly identical association data. We investigate several protein weighting schemes and compare their corresponding DAGs using yeast and human complexes. We find that the scheme incorporating weights based on information flow in the network of direct protein-protein interactions produces biologically most meaningful DAGs. In either yeast or human, isolated nodes form a large proportion of the final hierarchy. While most connected components encompass very few nodes, the largest one for each species contains a sizable portion of all nodes. By considering examples of subgraphs composed of nodes containing a specified protein, we illustrate that the graphs' topological features can correctly suggest the biological roles of protein complexes. The input data, final results and the source code are available at ftp://ftp.ncbi.nlm.nih.gov/pub/qmbpmn/ProteinComplexDAG/.
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Affiliation(s)
- Aleksandar Stojmirović
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States
| | - Yi-Kuo Yu
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States
- * E-mail:
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Kim YA, Przytycka TM. Bridging the Gap between Genotype and Phenotype via Network Approaches. Front Genet 2013; 3:227. [PMID: 23755063 PMCID: PMC3668153 DOI: 10.3389/fgene.2012.00227] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/10/2012] [Indexed: 11/15/2022] Open
Abstract
In the last few years we have witnessed tremendous progress in detecting associations between genetic variations and complex traits. While genome-wide association studies have been able to discover genomic regions that may influence many common human diseases, these discoveries created an urgent need for methods that extend the knowledge of genotype-phenotype relationships to the level of the molecular mechanisms behind them. To address this emerging need, computational approaches increasingly utilize a pathway-centric perspective. These new methods often utilize known or predicted interactions between genes and/or gene products. In this review, we survey recently developed network based methods that attempt to bridge the genotype-phenotype gap. We note that although these methods help narrow the gap between genotype and phenotype relationships, these approaches alone cannot provide the precise details of underlying mechanisms and current research is still far from closing the gap.
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Affiliation(s)
- Yoo-Ah Kim
- National Center for Biotechnology Information, National Institutes of Health, National Library of Medicine Bethesda, MD, USA
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Abstract
Complex diseases are caused by a combination of genetic and environmental factors. Uncovering the molecular pathways through which genetic factors affect a phenotype is always difficult, but in the case of complex diseases this is further complicated since genetic factors in affected individuals might be different. In recent years, systems biology approaches and, more specifically, network based approaches emerged as powerful tools for studying complex diseases. These approaches are often built on the knowledge of physical or functional interactions between molecules which are usually represented as an interaction network. An interaction network not only reports the binary relationships between individual nodes but also encodes hidden higher level organization of cellular communication. Computational biologists were challenged with the task of uncovering this organization and utilizing it for the understanding of disease complexity, which prompted rich and diverse algorithmic approaches to be proposed. We start this chapter with a description of the general characteristics of complex diseases followed by a brief introduction to physical and functional networks. Next we will show how these networks are used to leverage genotype, gene expression, and other types of data to identify dysregulated pathways, infer the relationships between genotype and phenotype, and explain disease heterogeneity. We group the methods by common underlying principles and first provide a high level description of the principles followed by more specific examples. We hope that this chapter will give readers an appreciation for the wealth of algorithmic techniques that have been developed for the purpose of studying complex diseases as well as insight into their strengths and limitations.
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Affiliation(s)
- Dong-Yeon Cho
- National Center for Biotechnology Information, NLM, NIH, Bethesda, Maryland, United States of America
| | - Yoo-Ah Kim
- National Center for Biotechnology Information, NLM, NIH, Bethesda, Maryland, United States of America
| | - Teresa M. Przytycka
- National Center for Biotechnology Information, NLM, NIH, Bethesda, Maryland, United States of America
- * E-mail:
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Stojmirović A, Bliskovsky A, Yu YK. CytoITMprobe: a network information flow plugin for Cytoscape. BMC Res Notes 2012; 5:237. [PMID: 22587372 PMCID: PMC3514294 DOI: 10.1186/1756-0500-5-237] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 04/29/2012] [Indexed: 11/14/2022] Open
Abstract
Background Cytoscape is a well-developed flexible platform for visualization, integration and analysis of network data. Apart from the sophisticated graph layout and visualization routines, it hosts numerous user-developed plugins that significantly extend its core functionality. Earlier, we developed a network information flow framework and implemented it as a web application, called ITM Probe. Given a context consisting of one or more user-selected nodes, ITM Probe retrieves other network nodes most related to that context. It requires neither user restriction to subnetwork of interest nor additional and possibly noisy information. However, plugins for Cytoscape with these features do not yet exist. To provide the Cytoscape users the possibility of integrating ITM Probe into their workflows, we developed CytoITMprobe, a new Cytoscape plugin. Findings CytoITMprobe maintains all the desirable features of ITM Probe and adds additional flexibility not achievable through its web service version. It provides access to ITM Probe either through a web server or locally. The input, consisting of a Cytoscape network, together with the desired origins and/or destinations of information and a dissipation coefficient, is specified through a query form. The results are shown as a subnetwork of significant nodes and several summary tables. Users can control the composition and appearance of the subnetwork and interchange their ITM Probe results with other software tools through tab-delimited files. Conclusions The main strength of CytoITMprobe is its flexibility. It allows the user to specify as input any Cytoscape network, rather than being restricted to the pre-compiled protein-protein interaction networks available through the ITM Probe web service. Users may supply their own edge weights and directionalities. Consequently, as opposed to ITM Probe web service, CytoITMprobe can be applied to many other domains of network-based research beyond protein-networks. It also enables seamless integration of ITM Probe results with other Cytoscape plugins having complementary functionality for data analysis.
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Affiliation(s)
- Aleksandar Stojmirović
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD 20894, USA
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Stojmirović A, Yu YK. Information flow in interaction networks II: channels, path lengths, and potentials. J Comput Biol 2012; 19:379-403. [PMID: 22409812 DOI: 10.1089/cmb.2010.0228] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In our previous publication, a framework for information flow in interaction networks based on random walks with damping was formulated with two fundamental modes: emitting and absorbing. While many other network analysis methods based on random walks or equivalent notions have been developed before and after our earlier work, one can show that they can all be mapped to one of the two modes. In addition to these two fundamental modes, a major strength of our earlier formalism was its accommodation of context-specific directed information flow that yielded plausible and meaningful biological interpretation of protein functions and pathways. However, the directed flow from origins to destinations was induced via a potential function that was heuristic. Here, with a theoretically sound approach called the channel mode, we extend our earlier work for directed information flow. This is achieved by constructing a potential function facilitating a purely probabilistic interpretation of the channel mode. For each network node, the channel mode combines the solutions of emitting and absorbing modes in the same context, producing what we call a channel tensor. The entries of the channel tensor at each node can be interpreted as the amount of flow passing through that node from an origin to a destination. Similarly to our earlier model, the channel mode encompasses damping as a free parameter that controls the locality of information flow. Through examples involving the yeast pheromone response pathway, we illustrate the versatility and stability of our new framework.
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Affiliation(s)
- Aleksandar Stojmirović
- National Central for Biotechnology Information, National Library of Medicine, National Institute of Health, Bethesda, Maryland, USA
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Kim YA, Przytycki JH, Wuchty S, Przytycka TM. Modeling information flow in biological networks. Phys Biol 2011; 8:035012. [PMID: 21572171 DOI: 10.1088/1478-3975/8/3/035012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Large-scale molecular interaction networks are being increasingly used to provide a system level view of cellular processes. Modeling communications between nodes in such huge networks as information flows is useful for dissecting dynamical dependences between individual network components. In the information flow model, individual nodes are assumed to communicate with each other by propagating the signals through intermediate nodes in the network. In this paper, we first provide an overview of the state of the art of research in the network analysis based on information flow models. In the second part, we describe our computational method underlying our recent work on discovering dysregulated pathways in glioma. Motivated by applications to inferring information flow from genotype to phenotype in a very large human interaction network, we generalized previous approaches to compute information flows for a large number of instances and also provided a formal proof for the method.
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Affiliation(s)
- Yoo-Ah Kim
- National Center for Biotechnology Information, NLM, NIH, 8600 Rockville Pike, Bethesda, MD 20894, USA.
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Abstract
Allosteric communication in proteins can be induced by the binding of effective ligands, mutations or covalent modifications that regulate a site distant from the perturbed region. To understand allosteric regulation, it is important to identify the remote sites that are affected by the perturbation-induced signals and how these allosteric perturbations are transmitted within the protein structure. In this study, by constructing a protein structure network and modeling signal transmission with a Markov random walk, we developed a method to estimate the signal propagation and the resulting effects. In our model, the global perturbation effects from a particular signal initiation site were estimated by calculating the expected visiting time (EVT), which describes the signal-induced effects caused by signal transmission through all possible routes. We hypothesized that the residues with high EVT values play important roles in allosteric signaling. We applied our model to two protein structures as examples, and verified the validity of our model using various types of experimental data. We also found that the hot spots in protein binding interfaces have significantly high EVT values, which suggests that they play roles in mediating signal communication between protein domains.
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Affiliation(s)
- Keunwan Park
- Department of Bio and Brain Engineering, KAIST, S Korea
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21
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Stojmirović A, Yu YK. Robust and accurate data enrichment statistics via distribution function of sum of weights. ACTA ACUST UNITED AC 2010; 26:2752-9. [PMID: 20826881 PMCID: PMC2958744 DOI: 10.1093/bioinformatics/btq511] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Motivation: Term-enrichment analysis facilitates biological interpretation by assigning to experimentally/computationally obtained data annotation associated with terms from controlled vocabularies. This process usually involves obtaining statistical significance for each vocabulary term and using the most significant terms to describe a given set of biological entities, often associated with weights. Many existing enrichment methods require selections of (arbitrary number of) the most significant entities and/or do not account for weights of entities. Others either mandate extensive simulations to obtain statistics or assume normal weight distribution. In addition, most methods have difficulty assigning correct statistical significance to terms with few entities. Results: Implementing the well-known Lugananni–Rice formula, we have developed a novel approach, called SaddleSum, that is free from all the aforementioned constraints and evaluated it against several existing methods. With entity weights properly taken into account, SaddleSum is internally consistent and stable with respect to the choice of number of most significant entities selected. Making few assumptions on the input data, the proposed method is universal and can thus be applied to areas beyond analysis of microarrays. Employing asymptotic approximation, SaddleSum provides a term-size-dependent score distribution function that gives rise to accurate statistical significance even for terms with few entities. As a consequence, SaddleSum enables researchers to place confidence in its significance assignments to small terms that are often biologically most specific. Availability: Our implementation, which uses Bonferroni correction to account for multiple hypotheses testing, is available at http://www.ncbi.nlm.nih.gov/CBBresearch/qmbp/mn/enrich/. Source code for the standalone version can be downloaded from ftp://ftp.ncbi.nlm.nih.gov/pub/qmbpmn/SaddleSum/. Contact:yyu@ncbi.nlm.nih.gov Supplementary information: Supplementary materials are available at Bioinformatics online.
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Affiliation(s)
- Aleksandar Stojmirović
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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Solving the apparent diversity-accuracy dilemma of recommender systems. Proc Natl Acad Sci U S A 2010; 107:4511-5. [PMID: 20176968 DOI: 10.1073/pnas.1000488107] [Citation(s) in RCA: 182] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recommender systems use data on past user preferences to predict possible future likes and interests. A key challenge is that while the most useful individual recommendations are to be found among diverse niche objects, the most reliably accurate results are obtained by methods that recommend objects based on user or object similarity. In this paper we introduce a new algorithm specifically to address the challenge of diversity and show how it can be used to resolve this apparent dilemma when combined in an elegant hybrid with an accuracy-focused algorithm. By tuning the hybrid appropriately we are able to obtain, without relying on any semantic or context-specific information, simultaneous gains in both accuracy and diversity of recommendations.
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Nibbe RK, Koyutürk M, Chance MR. An integrative -omics approach to identify functional sub-networks in human colorectal cancer. PLoS Comput Biol 2010; 6:e1000639. [PMID: 20090827 PMCID: PMC2797084 DOI: 10.1371/journal.pcbi.1000639] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 12/11/2009] [Indexed: 02/03/2023] Open
Abstract
Emerging evidence indicates that gene products implicated in human cancers often cluster together in “hot spots” in protein-protein interaction (PPI) networks. Additionally, small sub-networks within PPI networks that demonstrate synergistic differential expression with respect to tumorigenic phenotypes were recently shown to be more accurate classifiers of disease progression when compared to single targets identified by traditional approaches. However, many of these studies rely exclusively on mRNA expression data, a useful but limited measure of cellular activity. Proteomic profiling experiments provide information at the post-translational level, yet they generally screen only a limited fraction of the proteome. Here, we demonstrate that integration of these complementary data sources with a “proteomics-first” approach can enhance the discovery of candidate sub-networks in cancer that are well-suited for mechanistic validation in disease. We propose that small changes in the mRNA expression of multiple genes in the neighborhood of a protein-hub can be synergistically associated with significant changes in the activity of that protein and its network neighbors. Further, we hypothesize that proteomic targets with significant fold change between phenotype and control may be used to “seed” a search for small PPI sub-networks that are functionally associated with these targets. To test this hypothesis, we select proteomic targets having significant expression changes in human colorectal cancer (CRC) from two independent 2-D gel-based screens. Then, we use random walk based models of network crosstalk and develop novel reference models to identify sub-networks that are statistically significant in terms of their functional association with these proteomic targets. Subsequently, using an information-theoretic measure, we evaluate synergistic changes in the activity of identified sub-networks based on genome-wide screens of mRNA expression in CRC. Cross-classification experiments to predict disease class show excellent performance using only a few sub-networks, underwriting the strength of the proposed approach in discovering relevant and reproducible sub-networks. Intensive research on cancer has led to an understanding of many individual genes that may be important for the initiation and progression of tumors. However, since cancer is a progressive disease that results from accumulation of multiple mutations likely acting in concert, individual markers can only provide limited insights into cellular mechanisms that underlie tumorigenesis. For this reason, recent studies focus on identification of “sub-network markers”, that is, functionally associated genes that exhibit coordinate changes in molecular expression during cancer progression. However, expression of genes is most frequently interrogated at the mRNA level, which captures functional activity of genes only to a limited extent. Screening of protein expression, on the other hand, provides information on the abundance of functional gene products, but its scale is often limited compared to screening of mRNA expression. In this article, we develop a proteomics-driven computational method that searches for sub-network markers in human colorectal cancer, based on a seed of differentially expressed proteins identified by proteomic screening. Our results show that significant changes in the expression of these proteins is likely to be associated with coordinate changes in the expression of the genes whose products are functionally associated with these proteins. This analysis leads to novel insights in the synergistic processes that underlie tumorigenesis.
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Affiliation(s)
- Rod K Nibbe
- Center for Proteomics & Bioinformatics, Case Western Reserve University, Cleveland, Ohio, United States of America.
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Park K, Kim D. Localized network centrality and essentiality in the yeastâprotein interaction network. Proteomics 2009; 9:5143-54. [DOI: 10.1002/pmic.200900357] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Sun D, Zhou T, Liu JG, Liu RR, Jia CX, Wang BH. Information filtering based on transferring similarity. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:017101. [PMID: 19658838 DOI: 10.1103/physreve.80.017101] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2009] [Indexed: 05/28/2023]
Abstract
In this Brief Report, we propose an index of user similarity, namely, the transferring similarity, which involves all high-order similarities between users. Accordingly, we design a modified collaborative filtering algorithm, which provides remarkably higher accurate predictions than the standard collaborative filtering. More interestingly, we find that the algorithmic performance will approach its optimal value when the parameter, contained in the definition of transferring similarity, gets close to its critical value, before which the series expansion of transferring similarity is convergent and after which it is divergent. Our study is complementary to the one reported in [E. A. Leicht, P. Holme, and M. E. J. Newman, Phys. Rev. E 73, 026120 (2006)], and is relevant to the missing link prediction problem.
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Affiliation(s)
- Duo Sun
- Department of Modern Physics and Nonlinear Science Center, University of Science and Technology of China, Hefei Anhui 230026, People's Republic of China
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Abstract
Summary: Founded upon diffusion with damping, ITM Probe is an application for modeling information flow in protein interaction networks without prior restriction to the sub-network of interest. Given a context consisting of desired origins and destinations of information, ITM Probe returns the set of most relevant proteins with weights and a graphical representation of the corresponding sub-network. With a click, the user may send the resulting protein list for enrichment analysis to facilitate hypothesis formation or confirmation. Availability:ITM Probe web service and documentation can be found at www.ncbi.nlm.nih.gov/CBBresearch/qmbp/mn/itm_probe Contact:yyu@ncbi.nlm.nih.gov
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Affiliation(s)
- Aleksandar Stojmirović
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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