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 FallotIn developed countries, heart defects have anoccurrence of 0.8% in neonates and are responsible forabout 10% of childhood mortalityThe tetralogy of Fallot is one of the most common formof congenital heart diseaseResearch group composed of Systems Engineers at Loughborough University, within theSystems Modeling and Simulation Group Medical experts from the University of Rennes 1 5. Heart Development Embryonic heart development is a complex process that occursbetween 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 situationtaking place,the OFT should rotateendocardial cushions about 150 degrees,grow in the outflowclockwisetract (OFT) But there are several Different diseasemechanisms that canclassificationsdisrupt thiscorrespond toremodeling of OFTdifferent degrees ofrotation 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 leftthan it should be pulmonary stenosis : a ventricular septal defect right ventricle hypertrophy. The point that Project Fallot is currentlyinvestigating is the hypothesis that suggests thatthe tetralogy is in fact a "monology" - the latterthree defects occurring as a consequence of thefirst one. 9. Epithilelial to MesenchymalTransformation EMT is an important process in cardiacdevelopment and disease This period has many contributions tomorphogenetic processes in the embryonic heart,such as: the growth the endocardial cushions in theatrioventricular (AV) canal The growth of the outflow tract (OFT) 10. Multiscale Modeling (1) Although it is known which pathways are required forEMT in cardiac cushion development, there is limiteddetail on how these pathways function and interact Computer modeling provides a means to rapidly develop pathway models, based on what isknown and run simulations to form hypotheses. Different types of computational model are suitable fordifferent levels ofbiological scale Biochemical reactions can be represented asnetworks or ODEs Then we can use models at one level of scale, topass 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 andexisting cells are induced to differentiate into valveleaflet 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 Im 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 eventsleading to the release of Arachidonic Acid (AA)and Nitric Oxide (NO) Both intracellular messenger are able to activateplasmamembrane 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 Differentialbehaviour 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 SystemMarkup BiologyLanguage(SBML) COPASISoftware 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) complexcalcineurin/NFATnucl. 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) complexcalcineurin/NFAT nucl. 31. Results The behaviour seems to correspond topublications An objective would be to replace Cas simpleevent input with experimental data or data fromVEGF/AA/NO/Ca Model Another would be to perform more preciseanalysis on initial concentrations/parameters Another would be to perform positive feedbackwith VEGF 32. DSCR1/NFAT interactions (1) We just have seen the promotion of NFAT to thenucleus We have seen that once the NFAT is in the nucleus itcan activates VEGF We have also seen that it can perform either positiveor negative feedback to control the VEGF activation. In this section we will focus on the negative feedbackvia the DSCR1 protein DSCR1 has been shown to bind to calcineurin and toinhibit its activity, preventing the activation (dephosphorylation) of NFATand 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 ofthe 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 andrelated potential blocking therapies Michael Vagner and M. A. Q. Siddiqui, SignalTransduction in Early Heart Development (II) Wayne g. Fisher, Pei-Chi Yang, Ram K. Medikonduriand M. Saleet Jafri,NFAT and NFKB Activation in T Lymphocytes : AModel of Differential Activation of Gene Expression Abdulla T., Imms R., Schleich J-M. and Summers R :Multiscale Information Modelling for HeartMorphogenesis