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Predicting Long Term behavior of Genetic Regulatory Networks with Answer Set Programming

Predicting Long Term behavior of Genetic Regulatory Networks with Answer Set Programming

Using the declarative Answer Set Programming paradigm we showed how biological networks could be efficiently represented in a way that easily allowed computations on top of it.

Gustavo Torres

May 30, 2012
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  1. of 27 GENETIC REGULATORY NETWORKS (GRNs) 2 ASP for Long

    Term Behavior of GRNs GENE 1 GENE 3 GENE 2 mRNA 1 mRNA 2 mRNA 3 Protein 1 Protein 2 Protein 3 GRN
  2. of 27 GENETIC REGULATORY NETWORKS (GRNs) 2 ASP for Long

    Term Behavior of GRNs GENE 1 GENE 3 GENE 2 mRNA 1 mRNA 2 mRNA 3 Protein 1 Protein 2 Protein 3 GRN g1 g3 g3 inhibits g1 g2 activates g3 g2 BOOLEAN NETWORK g1, g2, g3 ∈ {0,1}
  3. of 27 WHY BOOLEAN NETWORKS? 3 ASP for Long Term

    Behavior of GRNs Simple enough to be scalable Detailed biological information is not often available Complex behavior can come from simple structure
  4. of 27 ASP for Long Term Behavior of GRNs ANSWER

    SET PROGRAMMING 4 Boolean Networks are defined according to a set of rules that control its dynamics E.g. if an inhibitor is present the gene will not be switched on in the next time step We rely on ASP, a rule based declarative framework, to flexibly describe the model
  5. of 27 ASP for Long Term Behavior of GRNs ANSWER

    SET PROGRAMMING 5 g2 g1 g3 .n g1 3 g1 g2 g3 - - 1 0 1 - 0 1 - 1 0 1 0 0 0 0 SAT ASP activates(g1,g1) inhibits(g3,g1) activates(g2,g1)
  6. of 27 ASP for Long Term Behavior of GRNs ANSWER

    SET PROGRAMMING 5 g2 g1 g3 .n g1 3 g1 g2 g3 - - 1 0 1 - 0 1 - 1 0 1 0 0 0 0 SAT ASP activates(g1,g1) inhibits(g3,g1) activates(g2,g1) inhibited(X,T+1) inhibits(Y,X) active(Y,T)
  7. of 27 ASP for Long Term Behavior of GRNs ANSWER

    SET PROGRAMMING 6 g2 g1 g3 .n g1 3 g1 g2 g3 - - 1 0 1 - 0 1 - 1 0 1 0 0 0 0 SAT ASP activates(g1,g1) inhibits(g3,g1) activates(g2,g1) inhibited(X,T+1) inhibits(Y,X) active(Y,T)
  8. of 27 ASP for Long Term Behavior of GRNs APPLICABILITY

    OF ASP 7 To show the use of ASP for Boolean Networks modeling we pursued the problem of calculating the attractors of the modeled dynamic system An attractor is a set of states in which the dynamics of the network cycles indefinitely These attractor states usually correspond to important biological decisions
  9. of 27 DYNAMICS OF GRNs: SYNCHRONOUS 8 g2 g1 g3

    100 111 110 001 010 101 011 000 g1=0 g2=1 g3=1 Boolean Network State Transition Graph (STG) ASP for Long Term Behavior of GRNs
  10. of 27 DYNAMICS OF GRNs: SYNCHRONOUS 9 g2 g1 g3

    100 111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs
  11. of 27 DYNAMICS OF GRNs: SYNCHRONOUS 10 g2 g1 g3

    100 111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs
  12. of 27 DYNAMICS OF GRNs: SYNCHRONOUS 11 g2 g1 g3

    100 111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs
  13. of 27 DYNAMICS OF GRNs: SYNCHRONOUS 12 g2 g1 g3

    100 111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs
  14. of 27 DYNAMICS OF GRNs: SYNCHRONOUS 13 g2 g1 g3

    100 111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs
  15. of 27 DYNAMICS OF GRNs: ATTRACTORS 14 g2 g1 g3

    100 111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs
  16. of 27 CALCULATING ALL ATTRACTORS 15 g2 g1 g3 100

    111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs Pick a path in the STG of size 2
  17. of 27 CALCULATING ALL ATTRACTORS 16 g2 g1 g3 100

    111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs Pick a path in the STG of size 4
  18. of 27 CALCULATING ALL ATTRACTORS 17 g2 g1 g3 100

    111 110 001 010 101 011 000 ASP for Long Term Behavior of GRNs Find cycles inside the path
  19. of 27 CALCULATING ALL ATTRACTORS 18 g2 g1 g3 100

    001 011 000 ASP for Long Term Behavior of GRNs Pick a path in the STG of size 4
  20. of 27 EXPERIMENTAL RESULTS 19 ASP for Long Term Behavior

    of GRNs T helper (Th) cells are a subgroup of lymphocytes important for the immune system Divided into Th1 and Th2 cells each responsible for different diseases Pedicini et al (2010) used gene knockout experiments to tell whether Th1 and Th2 are mutually exclusive
  21. of 27 EXPERIMENTAL RESULTS 20 ASP for Long Term Behavior

    of GRNs 0 5,00 10,00 15,00 20,00 COT GATA3 IKBKB IRAK IRF4 JAK1 JAK3 LCK MAF NFAT NFKB Solving time for the Th Cell Helper network (Pedicini et al (2010)) SAT ASP
  22. of 27 ASYNCHRONOUS BEHAVIOR 21 ASP for Long Term Behavior

    of GRNs In addition to SAT, which only implements finding attractors for the synchronous updated network we also considered asynchronously updated networks. An asynchronous updated network considers the fact that genes do not change their state all at the same moment
  23. of 27 EXTENDING ATTRACTORS TO ASYNCHRONOUS 22 g2 g1 g3

    001 000 011 010 111 110 101 100 ASP for Long Term Behavior of GRNs
  24. of 27 DYNAMICS OF GRNs: ASYNCHRONOUS 23 g2 g1 g3

    001 000 011 010 111 110 101 100 ASP for Long Term Behavior of GRNs
  25. of 27 CALCULATING ALL ATTRACTORS: ALGORITHM 24 changed ( X,

    T ) active ( X, T ) , inhibited ( X, T 1) , protein ( X ) , T > 0 . changed ( X, T ) inhibited ( X, T ) , active ( X, T 1) , protein ( X ) , T > 0 . N = # changed ( X, T ) , N 2 , protein ( X ) , T > 0 . active(g1, T), inhibited(g2, T), active(g3, T). Asynchronous 101 Do not repeat visited states ASP for Long Term Behavior of GRNs 001 000 011 010 111 110 101 100
  26. of 27 CALCULATING ALL ATTRACTORS: ALGORITHM 25 changed ( X,

    T ) active ( X, T ) , inhibited ( X, T 1) , protein ( X ) , T > 0 . changed ( X, T ) inhibited ( X, T ) , active ( X, T 1) , protein ( X ) , T > 0 . N = # changed ( X, T ) , N 2 , protein ( X ) , T > 0 . active(g1, T), inhibited(g2, T), active(g3, T). Asynchronous 101 Do not repeat visited states ASP for Long Term Behavior of GRNs 000 011 110
  27. of 27 CONCLUSIONS ‣ ASP provides a natural way to

    encode GRNs’ behavior and adds flexibility ‣ Attractors can be used as predictors of long term behavior of GRNs ‣ The running time for calculating all attractors becomes proportional to the number of attractors rather than in the size of the network (2n) 26 ASP for Long Term Behavior of GRNs
  28. of 27 ACKNOWLEDGMENTS ‣ Kathleen Marchal, Yves Van de Peer,

    Martine De Cock ‣ Dubrova, Teslenko (2011) A SAT based algorithm for finding Attractors in Synchronous Boolean Networks ‣ Pedicini, Barrenäs, Clancy, Castiglione, Hovig, Kanduri, Santoni et al (2010) Combining network modeling and gene expression microarray analysis to explore the dynamics of Th1 and Th2 cell regulation 27 ASP for Long Term Behavior of GRNs