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10 Endogenous and exogenous loading of extracellular vesicles for therapeutic delivery of renin-angiotensin system peptides in cardiomyocyte hypertrophy
  1. LS Downie,
  2. LM Work,
  3. SA Nicklin
  1. Institute of Cardiovascular and Medical Sciences, University of Glasgow


Introduction The RAS peptide angiotensin II (AngII) mediates cardiac hypertrophy. The counter-regulatory RAS axis peptide Angiotensin 1–7 [Ang-(1–7)] inhibits cardiomyocyte hypertrophy. EVs were purified from cardiomyocytes ± treatment with AngII or Ang-(1–7) to assess cardiomyocyte hypertrophy. EVs were loaded with Ang-(1–7) via electroporation for therapeutic delivery.

Methods H9c2 cardiomyocytes were untreated (control) or treated with AngII or Ang-(1–7). EVs were isolated from conditioned media by differential ultracentrifugation, characterised by BCA, western immunoblot, Nanosight and TEM and incubated with recipient cardiomyocytes. Next, cells were stained with F-Phalloidin actin and area measured. Gene expression of hypertrophy marker brain natriuretic peptide (BNP) was assessed by qRT-PCR. Control EVs were electroporated in the presence of Ang-(1–7) and levels determined by ELISA.

Results H9c2 cardiomyocyte-derived EV size was 101.0±2.4 nm and EV markers CD63 and TSG-101 were consistently detected. EVs from AngII treated cardiomyocytes significantly increased recipient cardiomyocyte area compared to control EVs [control: 3291.1±90.1 µm2 vs AngII:5252.3±125.4 µm2; p<0.001] and significantly increased BNP expression [p<0.017]. EVs isolated from Ang-(1–7) treated H9c2 cardiomyocytes significantly reduced AngII induced hypertrophy in recipient cardiomyocytes [AngII +Control EVs:5566.3±139.0µm2 vs AngII +Ang-(1–7) EVs:4212.7±132.1 µm2; p<0.01]. Electroporation loaded EVs with Ang-(1–7) [naïve EVs:0.0 pg/mL vs Ang-(1–7) EVs:342.3±9.1 pg/mL; p<0.001]. Ang-(1–7) loaded EVs significantly reduced AngII induced hypertrophy in recipient cardiomyocytes [Naive EVs:4641.2±35.3µm2 vs Ang-(1–7) EVs:2758.4±20.1µm2; p<0. 001].

Conclusion EVs isolated from AngII treated H9c2 cardiomyocytes stimulate recipient cardiomyocyte hypertrophy. EVs isolated from Ang-(1–7) treated cardiomyocytes inhibit hypertrophy. Furthermore, EVs exogenously loaded with Ang-(1–7) inhibit cardiomyocyte hypertrophy. These findings have implications for understanding the role of the RAS and EV function in cardiomyocytes.

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