=Paper= {{Paper |id=Vol-2042/paper37 |storemode=property |title=Visualizing Metabolomics Data in Directed Biological Networks |pdfUrl=https://ceur-ws.org/Vol-2042/paper37.pdf |volume=Vol-2042 |authors=Ryan Miller,Denise Slenter,Martina Kutmon,Jonathan Melius,Georg Summer,Chris Evelo,Egon Willighagen |dblpUrl=https://dblp.org/rec/conf/swat4ls/MillerSKMSEW17 }} ==Visualizing Metabolomics Data in Directed Biological Networks== https://ceur-ws.org/Vol-2042/paper37.pdf
                   Visualizing metabolomics data in directed biological networks

Denise Slenter1, Martina Kutmon1,2, Ryan Miller1, Jonathan Melius1, Georg Summer3, Chris T. Evelo1,2 and
Egon L. Willighagen1
1
 Department of Bioinformatics – BiGCaT, NUTRIM Research School, Maastricht University, The Netherlands
2
 Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, The Netherlands
3
 Department of Cardiology, Maastricht University, The Netherlands
E-mail: ryan.miller@maastrichtuniversity.nl



Background
     Metabolomics data describes the state of a biological          visualization functionality to investigate the identified
system at a phenotypic level. Unfortunately, not all                subnetworks. The generic nature of this approach opens up
measured metabolites can be linked to metabolite identities         the option to combine with other omics data sources, such
present in biological pathway models. The resulting                 as proteomics and transcriptomics.
sparseness makes it more complicated to use metabolomics
data in pathway and network analysis.
     In 2014, Posma et al. introduced MetaboNetworks [1], a
Matlab toolbox to create sub-networks between sets of
metabolites using the reactions from the KEGG database [2]
by calculating the shortest paths between them. Such
networks overcome the metabolic data sparseness by
focussing on the paths between the metabolites of interest.
To upscale this approach, we need to be able to combine
different pathway knowledge bases and introduce detailed
directionality information, ensuring the shortest paths follow
one-directional biological cause-and-effect paths.

Materials & Methods
    The presented work creates subnetworks of shortest,
directed pathways between active metabolites. First, with
the WikiPathways RDF [3], we created a directed network of
all metabolic reactions from the WikiPathways [4] and
                                                                                Figure 1: Directed network of metabolic reactions.
Reactome [5] pathway knowledgebase, see Figure 1. In the
next step, we identified the location(s) of the active              References
metabolites in the network, in which we match data with                  1.   J.M. Posma et al. "MetaboNetworks, an interactive Matlab-
nodes in the network using knowledge from the ChEBI                           based toolbox for creating, customizing and exploring sub-
ontology [6] and Wikidata [7]. This ontological linking                       networks from KEGG." Bioinformatics (2013): btt612.
                                                                         2.   M. Kanehisa et al. "KEGG: Kyoto Encyclopedia of Genes and
generalizes the more limited exact matching based on                          Genomes." NAR 28.1 (2000): 27-30.
metabolite identifiers. Finally, using the cyNeo4j app for               3.   A. Waagmeester et al. "Using the Semantic Web for Rapid
Cytoscape [8] we extracted the smallest connected                             Integration of WikiPathways with Other Biological Online Data
subnetwork between the changed metabolites using the                          Resources." PLoS Comput Biol 12.6 (2016): e1004989.
                                                                         4.   M. Kutmon et al. "WikiPathways: capturing the full diversity of
functionality of the graph database Neo4j.
                                                                              pathway knowledge." Nucleic acids research (2015): gkv1024.
    We will apply the described approach to study the                    5.   G. Joshi-Tope et al. "Reactome: a knowledgebase of biological
metabolic changes in diabetes patients reported in a publicly                 pathways." NAR 33.suppl 1 (2005): D428-D432.
available dataset in the MetaboLights repository [9].                    6.   K. Degtyarenko et al. "ChEBI: a database and ontology for
                                                                              chemical entities of biological interest." Nucleic acids research
                                                                              36.suppl 1 (2008): D344-D350.
Conclusion                                                               7.   D. Vrandečić et al. "Wikidata: a free collaborative
     We developed a new solution to visualize the biological                  knowledgebase." Communications of the ACM 57.10 (2014): 78-
pathways involved in sparse metabolomics data. Using                          85.
knowledge from two pathway resources and ontology-based                  8.   G. Summer et al. "cyNeo4j: connecting Neo4j and Cytoscape."
                                                                              Bioinformatics 31.23 (2015): 3868-3869.
approaches, we can show the directed networks between
                                                                         9.   K. Haug et al. "MetaboLights—an open-access general-purpose
active metabolites from metabolomics data. The data from                      repository for metabolomics studies and associated meta-data."
both resources is made interoperable by collapsing                            NAR (2012): gks1004.
metabolites in the pathways into single nodes in the                     10. J. Partner et al. Neo4j in action. Manning,, 2015.
biological networks using ontological approaches. This                   11. P. Shannon et al. "Cytoscape: a software environment for
                                                                              integrated models of biomolecular interaction networks."
explicit ontological linking allows for precise biological                    Genome Research 13.11 (2003): 2498-2504.
interpretation of the paths. By using Neo4j [10] and
Cytoscape [11], we ensure the computational calculation
environment for larger networks as well as advanced