Abstract 942 Soluble adenylyl cyclase affects AKT and CaMKII activity in adult rat cardiomyocytes, but not in H9c2 cells. Are H9c2 cells really cardiomyocytelike?

Clin Res Cardiol (2021) DOI DOI https://doi.org/10.1007/s00392-021-01843-w
Soluble adenylyl cyclase affects AKT and CaMKII activity in adult rat cardiomyocytes, but not in H9c2 cells. Are H9c2 cells really cardiomyocytelike?
N. Radev¹, T. Poppenga¹, A. Al Haj¹, H. G. Mannherz¹, A. Mügge², N. Hamdani³, D. Cimiotti⁴, K. Jaquet⁵, für die Studiengruppe: AG13
¹Molekulare und Experimentelle Kardiologie, Ruhr-Universität Bochum, Bochum; ²Med. Klinik II, Kardiologie, Kath. Klinikum Bochum gGmbH, Bochum; ³Institut für Physiologie, Abt. für Systemphysiologie - MA2/148, Ruhr-Universität Bochum, Bochum; ⁴Forschungslabor Molekulare Kardiologie, Kath. Klinikum Bochum gGmbH, Bochum; ⁵Molekulare Kardiologie, Ruhr-Universität Bochum, Bochum;
Soluble adenylyl cyclase (sAC) is pivotal in stress-induced cardiac hypertrophy, however involved signaling pathways are unknown. We investigated if sAC acts via AKT or CaMKII. For this we tried to use H9c2 cellline as an alternative to the difficult to handle adulat rat cardiomyocytes. In recent years, there has been an increasing interest in H9c2 myoblast cell line, initially isolated from embryonic ventricular rat heart tissue, and which is used as an in vitro cardiac-like cell model for skeletal and cardiac muscle. In the presence of retinoic acid (RA) undifferentiated H9c2 cells should differentiate into cardiac-like cells. Our aim is to verify if H9c2 cells could be used for our research on the role of soluble adenylyl cyclase (sAC) in cardiac hypertrophy. In our study H9c2 cells were cultured in media with low serum level and with 1 µM RA for a maximum period of 31 days. For comparison, cardiomyocytes from adult WistarKyoto rats were isolated. Data to identify selected muscle and signaling proteins were collected. Muscle proteins which are relevant for our research for example, were cardiac myosin binding protein C (MyBPC) and cardiac troponin T (cTnT). The presence of proteins was investigated by western blot analysis and immunohistochemistry. However, MyBPC could not be observed in H9c2 cells neither with nor without the presence of RA. Similar results are shown for cTnT. Its expression in H9c2 cells was lower compared to the expression in cardiomyocytes and was independent on the presence of RA. In addition, the signaling protein sAC was not detected in H9c2 cells. But CaMKII is present in both, though H9c2 cells and cardiomyocytes show different band pattern analyzed by western blot. In isolated adult rat cardiomyocytes we could show that sAC regulates AKT and CaMKII activity. Furthermore we have shown that H9c2 cells cannot be used to study stress induced cardiac hypertrophy, and in addition we verified that H9c2 cells are not a suitable replacement for cardiomyocytes.
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