1. Internship at Loughborough,
Jocelyn Griselle
Heart Development pathway
Jocelyn Griselle

2. Loughborough University
 40 Research Institutes and Centers
 23 academic departments
 Systems Engineering department
 Advanced Systems, Modeling and Simulation
Research Group
Development of better modeling and
simulation methodologies, but also application of
state of the art techniques to help understand and
predict the behavior of complex systems

3. Outline
 Project Fallot
 Heart Developement
 Heart Disease
 Multiscale Modelling
 My project : the NFAT/VEGF pathway
 VEGF / AA / NO / Ca pathway
 Ca2+ / Calcinerin / NFAT pathway
 DSCR1/NFAT pathway
 Conclusion

4. Project Fallot
•In developed countries, heart defects have an
occurrence of 0.8% in neonates and are responsible for
about 10% of childhood mortality
•The tetralogy of Fallot is one of the most common form
of congenital heart disease
•Research group composed of
• Systems Engineers at Loughborough University, within the
Systems Modeling and Simulation Group
• Medical experts from the University of Rennes 1

5. Heart Development
 Embryonic heart development is a complex process that occurs
between week 3 and 6 of gestation
 They are 3 main processes in embryonic heart development:
 fusion of the endocardial tubes
 heart looping
 wedging.

6. Heart Disease (1)
 While heart looping is  In the normal situation
taking place, the OFT should rotate
endocardial cushions about 150 degrees,
grow in the outflow clockwise
tract (OFT)  But there are several
 Different disease mechanisms that can
classifications disrupt this
correspond to remodeling of OFT
different degrees of
rotation

7. Heart Disease (2)
 Tetralogy of Fallot
 The classification of Double Outlet Right Ventricle
(DORV) overlaps with the tetralogy of Fallot with
rotation varying from about 90 to 140 degrees.

8. Heart Disease (3)
 The tetralogy of Fallot is defined as:
 an over-riding aorta - displaced further to the left
than it should be
 pulmonary stenosis : a ventricular septal defect
 right ventricle hypertrophy.
 The point that Project Fallot is currently
investigating is the hypothesis that suggests that
the tetralogy is in fact a "monology" - the latter
three defects occurring as a consequence of the
first one.

9. Epithilelial to Mesenchymal
Transformation
 EMT is an important process in cardiac
development and disease
 This period has many contributions to
morphogenetic processes in the embryonic heart,
such as:
 the growth the endocardial cushions in the
atrioventricular (AV) canal
 The growth of the outflow tract (OFT)

10. Multiscale Modeling (1)
 Although it is known which pathways are required for
EMT in cardiac cushion development, there is limited
detail on how these pathways function and interact
 Computer modeling provides a means
 to rapidly develop pathway models, based on what is
known
 and run simulations to form hypotheses.
 Different types of computational model are suitable for
different levels ofbiological scale
 Biochemical reactions can be represented as
networks or ODEs
 Then we can use models at one level of scale, to
pass information to models at another level of scale.

11. Multiscale Modeling (2)

12. My project
Protein interaction : the NFAT/VEGF pathway
VEGF / AA / NO / Ca Axis
Ca2+ / Calcinerin / NFAT Axis
DSCR1/NFAT pathway

13. VEGF/NFAT pathway (1)
 VEGF is a pleiotropic factor that regulates :
 cell proliferation
 vascular permeability
 chemotaxis
 survival in endothelial cells vasculogenesis
 angiogenesis
 In the developing embryo VEGF must be tightly
controlled during valve development

14. VEGF/NFAT pathway (2)
 In the first stage, activated NFAT represses VEGF
gene expression
 lower levels of VEGF
 Permits the transformation and migration of
mesenchymal cells into the cardiac jelly
 In the second phase, activated NFAT activates
VEGF gene expression
 mesenchymal cell proliferation is stopped and
existing cells are induced to differentiate into valve
leaflet precursors
 VEGF act as a trigger

15. VEGF/NFAT pathway (3)
 This control is done via the NFAT/VEGF pathway

16. Sum up
 Heart Development
 Heart Disease
 Tetralogy of Fallot
 EMT
 Control of VEGF level
 NFAT/VEGF pathway
 VEGF / AA / NO / Ca Axis
 Ca2+ / Calcinerin / NFAT Axis
 DSCR1/NFAT Axis

17. My model
 The model I'm willing to develop is divided into 3
parts
 VEGF activates Calcium influx via Nitric Oxide (NO)
and Arachidonic Acid (AA)
 Calcium influx promote NFAT in the nucleus
 DSCR1 compete with NFAT to bind to calcineurin
 And is using two different tools
 Matlab ODE
 System Biology Markup Language
within COPASI software

18. VEGF / AA / NO / Ca Axis (1)
 VEGF binds to Tirosine Kinase Receptor (RTK)
 RTK activate a series of intracellular events
leading to the release of Arachidonic Acid (AA)
and Nitric Oxide (NO)
 Both intracellular messenger are able to activate
plasmamembrane calcium channels

19. VEGF / AA / NO / Ca Axis (2)
 Extraction of the
Mathematical model
from Tubulogenesis
(formation of tubules
in epithelial or
endothelial cells)

20. VEGF / AA / NO / Ca Axis (3)
 Using deterministic  Focus on temporal
Ordinary Differential behaviour
Equations

21. VEGF / AA / NO / Ca Axis (3)

22. Matlab Code

23. Results

24. Ca2+ / Calcinerin / NFAT Axis
 Ca2+ influx activates Calcineurin
 Calcinerin dephosphorylates NFAT
 Which promote NFAT translation into the nucleus
 Where it activates or represses target gene

25. Ca2+ / Calcinerin / NFAT Axis
 System
Markup
Biology
Language
(SBML)
 COPASI
Software
 Graphic
Interface
 Deterministic
and
stochastic
simulations

26. Ca2+ / Calcinerin / NFAT Axis
 Model already done via SBML code, 4 stages
 Calcium inflow to cell (cytosol)
 Activation of calcinerium
 Calcinerium + NFAT(P) calcineurin/NFAT(P)
complex
 Calcineurin/NFAT(P) complex calcineurin/NFAT
nucl.

27. Calcium inflow to cell
 Input triggered by a simple event algorithm
 Ca=1 umol/l for t=[0..10] and t=[100..110]

28. Activation of calcinerium

29. Calcinerium + NFAT(P)
calcineurin/NFAT(P) complex

30. Calcineurin/NFAT(P) complex
calcineurin/NFAT nucl.

31. Results
 The behaviour seems to correspond to
publications
 An objective would be to replace Ca’s simple
event input with experimental data or data from
VEGF/AA/NO/Ca Model
 Another would be to perform more precise
analysis on initial concentrations/parameters
 Another would be to perform positive feedback
with VEGF

32. DSCR1/NFAT interactions (1)
 We just have seen the promotion of NFAT to the
nucleus
 We have seen that once the NFAT is in the nucleus it
can activates VEGF
 We have also seen that it can perform either positive
or negative feedback to control the VEGF activation.
 In this section we will focus on the negative feedback
via the DSCR1 protein
 DSCR1 has been shown to bind to calcineurin and to
inhibit its activity,
 preventing the activation (dephosphorylation) of NFAT
and its translocation to the nucleus.

33. DSCR1/NFAT interactions (2)

34. Perspectives
 For now several model have been made
 Need to put them together
 Parameter analysis to improve the accuracy of
the model
 RGB video processing to get experimental data

35. Conclusion
 This is only a start
 Great experience
 As a biological engineer
 As a research student
 As a foreign student

36. References
 Scianna, M., et al.
A multiscale hybrid approach for vasculogenesis and
related potential blocking therapies
 Michael Vagner and M. A. Q. Siddiqui, Signal
Transduction in Early Heart Development (II)
 Wayne g. Fisher, Pei-Chi Yang, Ram K. Medikonduri
and M. Saleet Jafri,
NFAT and NFKB Activation in T Lymphocytes : A
Model of Differential Activation of Gene Expression
 Abdulla T., Imms R., Schleich J-M. and Summers R :
Multiscale Information Modelling for Heart
Morphogenesis