Calmodulin kinase II inhibition protects against myocardial cell apoptosis in vivo.
Inhibition of the multifunctional Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) or depletion of sarcoplasmic reticulum (SR) Ca(2+) stores protects against apoptosis from excessive isoproterenol (Iso) stimulation in cultured ventricular myocytes, suggesting that CaMKII inhibition could be a novel approach to reducing cell death in conditions of increased adrenergic tone, such as myocardial infarction (MI), in vivo. We used mice with genetic myocardial CaMKII inhibition due to transgenic expression of a highly specific CaMKII inhibitory peptide (AC3-I) to test whether CaMKII was important for apoptosis in vivo. A second line of mice expressed a scrambled, inactive form of AC3-I (AC3-C). AC3-C and wild-type (WT) littermates were used as controls. AC3-I mice have reduced SR Ca(2+) content and are resistant to Iso- and MI-induced apoptosis compared with AC3-C and WT mice. Phospholamban (PLN) is a target for modulation of SR Ca(2+) content by CaMKII. PLN(-/-) mice have increased susceptibility to Iso-induced apoptosis. Verapamil pretreatment prevented Iso-induced apoptosis in PLN(-/-) mice, indicating the involvement of a Ca(2+)-dependent pathway. AC3-I and AC3-C mice were bred into a PLN(-/-) background. Loss of PLN increased and equalized SR Ca(2+) content in AC3-I, AC3-C, and WT mice and abolished the resistance to apoptosis in AC3-I mice after MI. There was a trend (P = 0.07) for increased Iso-induced apoptosis in AC3-I mice lacking PLN compared with AC3-I mice with PLN. These findings indicate CaMKII is proapoptotic in vivo and suggest that regulation of SR Ca(2+) content by PLN contributes to the antiapoptotic mechanism of CaMKII inhibition.
Yang
Yingbo
Y
Dept. of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Zhu
Wei-Zhong
WZ
Joiner
Mei-ling
ML
Zhang
Rong
R
Oddis
Carmine V
CV
Hou
Yue
Y
Yang
Jinying
J
Price
Edward E
EE
Gleaves
Linda
L
Eren
Mesut
M
Ni
Gemin
G
Vaughan
Douglas E
DE
Xiao
Rui-Ping
RP
Anderson
Mark E
ME
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D047908:Intracellular Signaling Peptides and Proteins; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014700:Verapamil / Q000494:pharmacology; D000099211:Phospholamban
D000318:Adrenergic beta-Agonists; D002118:Calcium; D002121:Calcium Channel Blockers; D002135:Calcium-Binding Proteins; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007545:Isoproterenol; D014700:Verapamil; D000099211:Phospholamban; C514810:Camk2n2 protein, mouse