The Modulation of Cardiac Contractile Function by the Pharmacological and Toxicological Effects of Urocortin2.
Urocortin2 (Ucn2) has been revealed to enhance cardiac function in heart failure. However, the pharmacological and toxicological effects of Ucn2 on cardiomyocytes are incompletely understood. In this study, we investigated the possible mechanisms of Ucn2 on mediating the contractility of cardiomyocytes. Mechanical properties and intracellular Ca(2+) properties were measured in isolated cardiomyocytes from different treatment groups. The stress signaling was evaluated using Western blot. The results demonstrated that Ucn2 induced maximal velocity of shortening (+dL/dt), peak height, peak shortening (PS) amplitude, maximal velocity of relengthening (-dL/dt), accompanied by a significant rise in intracellular Ca(2+) level and a fall of the mean time constant of Ca(2+) transient decay (Tau) in WT cardiomyocytes. However, these effects were abolished by preincubation of type 2 CRF receptors (CRFR2) antagonist anti-sauvagine 30 (a-SVG-30). We also found that Ucn2 treatment activated the AMPK pathway in isolated cardiomyocytes via CRFR2. Furthermore, Ucn2 induced protein kinase A (PKA) and phospholamban (PLN) phosphorylation. Pretreatment of PKA inhibitor H89 reduced the inotropic and lusitropic effects of Ucn2 as well as decreased the intracellular Ca(2+) load and slowed down the Ca(2+) transient decay. We also showed that preincubation of Compound C, an inhibitor of AMPK, inhibited the phosphorylation of PKA and the intracellular Ca(2+) level in cardiomyocytes without affecting the contractile function and the Tau of cardiomyocytes. Taken together, it suggests that Ucn2 facilitate the contractility of cardiomyocytes via activating both AMPK and PKA.
State University of New York at Buffalo, Buffalo, New York 14214.
Si
S
Chen
*College of Life Sciences, Yantai University, Yantai, Shandong 264005.
Zhenhua
Z
Wang
*College of Life Sciences, Yantai University, Yantai, Shandong 264005, Key Laboratory of Pharmacology and Molecular Drug Evaluation, School of Pharmacy, Yantai University, Yantai, Shandong 264005.
Bo
B
Xu
School of Life Sciences, Lanzhou University, Lanzhou, Gansu 730000.
Xiangquan
X
Mi
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi 39216, and The First Affiliated Hospital, Jilin University, Changchun, Jilin 130000.
Wanqing
W
Sun
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi 39216, and The First Affiliated Hospital, Jilin University, Changchun, Jilin 130000.
Nanhu
N
Quan
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi 39216, and The First Affiliated Hospital, Jilin University, Changchun, Jilin 130000.
Lin
L
Wang
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi 39216, and.
Xingchi
X
Chen
The First Affiliated Hospital, Jilin University, Changchun, Jilin 130000.
Quan
Q
Liu
The First Affiliated Hospital, Jilin University, Changchun, Jilin 130000.
Yang
Y
Zheng
The First Affiliated Hospital, Jilin University, Changchun, Jilin 130000.
Jiyan
J
Leng
Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi 39216, and jli3@umc.edu.
Ji
J
Li
D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D002135:Calcium-Binding Proteins / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004789:Enzyme Activation; D006727:Hormone Antagonists / Q000494:pharmacology; D008297:Male; D008810:Mice, Inbred C57BL; D009200:Myocardial Contraction / Q000187:drug effects*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D018019:Receptors, Corticotropin-Releasing Hormone / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D054832:Urocortins / Q000633:toxicity*; D000099211:Phospholamban
D055372:AMP-Activated Protein Kinases; D002135:Calcium-Binding Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D006727:Hormone Antagonists; D047428:Protein Kinase Inhibitors; D018019:Receptors, Corticotropin-Releasing Hormone; D054832:Urocortins; D000099211:Phospholamban; C101531:CRF receptor type 2
AMPK; PKA; Ucn2; cardiac toxicology; contractile function