DECLARATION OF CONFLICT OF INTEREST

Transcription

1 DECLARATION OF CONFLICT OF INTEREST

2 A potential anti-hypertrophic agent Riham Abouleisa

3 Cardiac hypertrophy is a compensatory response to maintain function during increased stress. A sustained hypertrophic response predisposes the heart to cardiac diseases. Treatment of hypertrophy is considered to be a promising target for treatment of heart failure. anti-hypertrophic agent increased stress sustained hypertrophic response

4 Plasma membrane calcium ATPase isoform 4 PMCA4 PMCA4 calcineurin ATP Ca +2 ADP PMCA is a calcium transporting enzyme. In the heart, PMCA4 plays a crucial role in regulating signalling proteins (Buch et al, 2005; Cartwright, 2005). Calcineurin which is a protein involved in the development of pathological cardiac hypertrophy (Molkentin, 1998 ).

5 KO WT KO WT PMCA4 knockout mice are protected from cardiac hypertrophy after TAC TAC: Transverse Aortic Constriction PMCA4 calcineurin Sham TAC Sham TAC (n=10 (Buch in et al, each 2005) group,*p<0.05, WT TAC vs PMCA4 ko TAC).

6 Hypothesis Aims Specific 1- Identification pharmacological of the first inhibitor PMCA4 of specific PMCA4 inhibitor. may act 2- Elucidation as a novel of the anti effect hypertrophic of the identified agent. inhibitor on the development of cardiac hypertrophy in vitro. 3-Confirmation of the anti-hypertrophic effect in vivo. 4- Investigation of cellular mechanism involved.

7 PMCA4 Ca 2+ ADP ATP Coupled enzyme assay Screened 1300 compounds of medically optimised drug library AP2

8 Inhibition % PMCA4 SERCA PMCA1 Na/K ATPase IC 50 = 0.1 µm AP2 concentration (µm) AP2 is the first specific PMCA4 inhibiting compound

9 Relative value Control +PE +PE+1µM AP2 +PE+5µM AP2 +PE+10µM AP2 * * PMCA4 inhibition with * AP2 reduced the hypertrophic response in vitro PE AP2(µM)

10 HW / TL (mg/mm) Fibrosis % AP2 Sham TAC Vehicle TAC AP2 Sham TAC TAC Vehicle Vehicle AP2 PMCA4 inhibition with AP2 * treated the hypertrophic response in vivo TAC AP μm 2 * TAC AP

11 Relative value NRCM PE AP2 PMCA4 Calcineurin NFAT luciferase activity Immunostaining for NFAT localisation * * P NFAT control control+pe nucleus PE AP2(µM) PE+1μM AP2 +PE+5μM AP2 +PE+10μMAP2 (Buch (Molkentin, et al, 2005) 1998 ) Hypertrophic response

12 AP2 Ca +2 PMCA4 Calcineurin 10μM AP2 NRCM infected with genetically modified calcium sensor (Gcamp2) viruses Cytoplasmic- GCamP2 Ca +2 50% Perfusion with Plain Tyrode s solution followed by tyroid solution containing 10µM AP2 PMCA4- GCamP2 Monitor the calcium oscillation during electric stimulation at 1Hz

13 1) AP2 is the first specific inhibitor for PMCA4 activity. 2) Pharmacological inhibition of PMCA4, with AP2, reduces the hypertrophic response in vitro and in vivo. 3) PMCA4 inhibition with AP2 reduces calcium oscillations in the microdomain around PMCA4 resulting in reduced calcineurin activation.

14 Pharmaceutical companies Academia Innovative drug New target and early stage compound AP2 is an early stage compound from which to develop a novel anti-hypertrophic agent

15 Acknowledgements Heart failure research group Supervisors Dr. Elizabeth Cartwright Prof. Ludwig Neyses Advisor Dr. Mamas Mamas ORS

16 A potential anti-hypertrophic agent Riham Abouleisa

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18 sec Indo1 ratio Indo-1 ratio Adult mice cardiomyocytes (3-4 months) loaded with the calcium dye Indo-I Stimulated at a frequency of 1Hz before AP2 After AP Perfusion with Tyrode s solution containing 10 µm AP Tau 0.25 Amplitude N=10 different cells from 3 independent animals in each group Before AP2 After AP Before AP2 After AP2

19 Fluorescent intensity Nitic oxid bioavailability test 0 1uM 2uM 5uM 10uM NRCM were incubated with AP2 for 24 hours Stained with DAF FM (NO sensitive dye Using live cell imaging to look at NO ptroduction 0 1uM 2uM 5uM 10uM

20 TAC Sham HW/TL (mg/mm) Prevention experiment in vivo Week 0 week 1 week 2 TAC AP2 treatment TAC start analysis * Vehicle AP2 TAC Vehicle AP2 (n=9-11 in each group,*p<0.05,tac-vehicle vs TAC-AP2).

21 Fold induction Does AP2 have a direct effect on calcineurin activity? Adv control Adv CnA Adv CnA Adv CnA Adv CnA AP2 (µm) N=4 independent experiments

22 HW / TL (mg/mm) PMCA4 -/- mice AP2 PMCA4 -/- mice Sham TAC Vehicle Vehicle TAC AP2 Sham Vehicle TAC Vehicle TAC AP2