Reil, Jan-Christian and Reil, Gert-Hinrich and Kovacs, Arpad and Sequeira, Vasco and Waddingham, Mark T. and Lodi, Maria and Herwig, Melissa and Ghaderi, Shahrooz and Kreusser, Michael M. and Papp, Zoltan and Voigt, Niels and Dobrev, Dobromir and Meyhoefer, Svenja and Langer, Harald F. and Maier, Lars S. and Linz, Dominik and Muegge, Andreas and Hohl, Mathias and Steendijk, Paul and Hamdani, Nazha (2020) CaMKII activity contributes to homeometric autoregulation of the heart: A novel mechanism for the Anrep effect. JOURNAL OF PHYSIOLOGY-LONDON, 598 (15). pp. 3129-3153. ISSN 0022-3751, 1469-7793
Full text not available from this repository. (Request a copy)Abstract
Key points The Anrep effect represents the alteration of left ventricular (LV) contractility to acutely enhanced afterload in a few seconds, thereby preserving stroke volume (SV) at constant preload. As a result of the missing preload stretch in our model, the Anrep effect differs from the slow force response and has a different mechanism. The Anrep effect demonstrated two different phases. First, the sudden increased afterload was momentary equilibrated by the enhanced LV contractility as a result of higher power strokes of strongly-bound myosin cross-bridges. Second, the slightly delayed recovery of SV is perhaps dependent on Ca2+/calmodulin-dependent protein kinase II activation caused by oxidation and myofilament phosphorylation (cardiac myosin-binding protein-C, myosin light chain 2), maximizing the recruitment of available strongly-bound myosin cross-bridges. Short-lived oxidative stress might present a new facet of subcellular signalling with respect to cardiovascular regulation. Relevance for human physiology was demonstrated by echocardiography disclosing the Anrep effect in humans during handgrip exercise. The present study investigated whether oxidative stress and Ca2+/calmodulin-dependent protein kinase II (CaMKII) activity are involved in triggering the Anrep effect. LV pressure-volume (PV) analyses of isolated, preload controlled working hearts were performed at two afterload levels (60 and 100 mmHg) in C57BL/6N wild-type (WT) and CaMKII-double knockout mice (DKOCaMKII). In snap-frozen WT hearts, force-pCa relationship, H(2)O(2)generation, CaMKII oxidation and phosphorylation of myofilament and Ca(2+)handling proteins were assessed. Acutely raised afterload showed significantly increased wall stress, H(2)O(2)generation and LV contractility in the PV diagram with an initial decrease and recovery of stroke volume, whereas end-diastolic pressure and volume, as well as heart rate, remained constant. Afterload induced increase in LV contractility was blunted in DKOCaMKII-hearts. Force development of single WT cardiomyocytes was greater with elevated afterload at submaximal Ca(2+)concentration and associated with increases in CaMKII oxidation and phosphorylation of cardiac-myosin binding protein-C, myosin light chain and Ca(2+)handling proteins. CaMKII activity is involved in the regulation of the Anrep effect and associates with stimulation of oxidative stress, presumably starting a cascade of CaMKII oxidation with downstream phosphorylation of myofilament and Ca(2+)handling proteins. These mechanisms improve LV inotropy and preserve stroke volume within few seconds.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | BINDING-PROTEIN-C; STRETCH-ACTIVATED CHANNELS; KINASE-II; PERFUSION-PRESSURE; CARDIAC-MUSCLE; PHOSPHORYLATION; FORCE; RAT; CONTRACTION; FAILURE; Anrep effect; CaMKII; Ca(2+)handling proteins; cMyBP-C; elastance-time curve; end-systolic elastance (Ees); LV contractility; myofilament phosphorylation |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Innere Medizin II |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 17 Mar 2021 10:48 |
| Last Modified: | 17 Mar 2021 10:48 |
| URI: | https://pred.uni-regensburg.de/id/eprint/44119 |
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