Characterization of cardiac stress (Takotsubo Cardiomyopathy)-related miRNAs ex vivo

Anselm Derda, ESC Congress 2015NHLI – Prof. Sian Harding

IMTTS – Prof. Thomas Thum

1. 2. 3.

Isolation of LV rat myocytes

Transfection & Incubation for 48h Control/Inhibitor/Mimic of miR-16

Contractility/IonOptix

Basal contractility

Precursor of miR-16 reduced contractility

Inhibitor of miR-16 increased contractility

N(rat) = 5MEAN + SEM

N(rat) = 5MEAN + SEM

p < 0.0001

p = 0.0194

17 22

16 16

Basal contractility

1. 2. 3.

Isolation of LV rat myocytes

Transfection & Incubation for 48h Control/Inhibitor/Mimic of miR-16

add Pertussis Toxin

Contractility/IonOptix

+ PTX

Contractility after block of Gi

PTX removed decreasing effect of mimic of miR-16

N(rat) = 4MEAN + SEM

p = 0.53

15 20

Contractility after block of Gi

1. 2. 3.

Isolation of LV rat myocytes

Transfection & Incubation for 48h Control/Inhibitor/Mimic of miR-16

Contractility/IonOptix

Contractility with isoprenaline simulating stress

+ isoprenaline

β1 β2

+ CGP

time

length

isoprenaline

CGPmax response

min response

Schematic: isoprenaline response

control

Inhibitor miR-16

max response min response

= = Inhibitor of miR-16 did not affect positive inotropic isoprenaline response

Conclusion

- miR-16 had an Gi-dependent negative inotropic effect on cardiomyocytes

- miR-16 did not affect the contractility of cardiomyocytes under stress

conditions induced by isoprenaline

- miR-16 is possibly influencing the tonic effect of Gi on contraction

- Further experiments are necessary for...

- ...evaluating signal cascade of miR-16 more precisely

- ...showing a possible interaction between miR-16 and adenylate cyclase