Abstract
Altered cardiac adaptation of physiologically hypertrophied heart during detraining remained obscure for long time. We had previously reported the switching of protein kinase C (PKC) isoforms (-α to -δ) associated with functional deterioration of heart at detraining in mice undergone swim exercise. Here we report that, myocardium targeted overexpression of insulin-like growth factor 1 (IGF1) and knockdown of insulin-like growth factor 1 receptor (IGF1R) during detraining and exercise respectively altered the activation of PKCs and eventual cardiac condition. Moreover, downregulation of mammalian target of rapamycin complex 2 (mTORC2) was recorded in both IGF1R knockdown or detraining groups. Additionally, knocking down of mTORC2 during exercise exhibited impaired cardiac condition. Interestingly, significantly increased interactions of mTORC2 with both PKCα and δ was recorded exclusively in exercise group. This interaction resulted into hydrophobic motif phosphorylation of both PKCs (Serine657-PKCα; Serine662-PKCδ). Serine phosphorylation on one hand activated PKCα mediated cell survival and on the other hand alleviated the apoptotic activity of PKCδ during exercise. Mutation of Serine662 of PKCδ in exercised mice showed higher Tyrosine311 phosphorylation with increased apoptotic load similar to that in detrained animals. These observations confirmed that differential and conditional activation of PKCs depend upon IGF1 induced mTORC2 activation. Furthermore, blocking of PKCα resulted in activated p53 which in turn repressed IGF1 expression during swim, mimicking the condition of detrained heart. In conclusion, this is the first report to unravel the intricate molecular mechanism of switching a physiologically hypertrophied heart to a pathologically hypertrophied heart during exercise withdrawal.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.