Detecting and removing inconsistencies between experimental data and signaling network topologies using integer linear programming on interaction graphs

PLoS Comput Biol. 2013;9(9):e1003204. doi: 10.1371/journal.pcbi.1003204. Epub 2013 Sep 5.

Abstract

Cross-referencing experimental data with our current knowledge of signaling network topologies is one central goal of mathematical modeling of cellular signal transduction networks. We present a new methodology for data-driven interrogation and training of signaling networks. While most published methods for signaling network inference operate on Bayesian, Boolean, or ODE models, our approach uses integer linear programming (ILP) on interaction graphs to encode constraints on the qualitative behavior of the nodes. These constraints are posed by the network topology and their formulation as ILP allows us to predict the possible qualitative changes (up, down, no effect) of the activation levels of the nodes for a given stimulus. We provide four basic operations to detect and remove inconsistencies between measurements and predicted behavior: (i) find a topology-consistent explanation for responses of signaling nodes measured in a stimulus-response experiment (if none exists, find the closest explanation); (ii) determine a minimal set of nodes that need to be corrected to make an inconsistent scenario consistent; (iii) determine the optimal subgraph of the given network topology which can best reflect measurements from a set of experimental scenarios; (iv) find possibly missing edges that would improve the consistency of the graph with respect to a set of experimental scenarios the most. We demonstrate the applicability of the proposed approach by interrogating a manually curated interaction graph model of EGFR/ErbB signaling against a library of high-throughput phosphoproteomic data measured in primary hepatocytes. Our methods detect interactions that are likely to be inactive in hepatocytes and provide suggestions for new interactions that, if included, would significantly improve the goodness of fit. Our framework is highly flexible and the underlying model requires only easily accessible biological knowledge. All related algorithms were implemented in a freely available toolbox SigNetTrainer making it an appealing approach for various applications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Computer Graphics*
  • Models, Biological
  • Signal Transduction*

Grants and funding

LGA and INM were funded via European Social Fund (ESF) and Greek National funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program: ERC. SK and RS acknowledge funding and support by the German Federal Ministry of Education and Research (“Virtual Liver” project (grant 0315744) and “JAK-Sys” project (grant 0316167B)) and by the Federal State of Saxony-Anhalt (Research Center “Dynamic Systems: Biosystems Engineering”). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.