High-density lipoprotein determines adult mouse cardiomyocyte fate after hypoxia-reoxygenation through lipoprotein-associated sphingosine 1-phosphate.
The lipid mediator sphingosine 1-phosphate (S1P) confers survival benefits in cardiomyocytes and isolated hearts subjected to oxidative stress. High-density lipoprotein (HDL) is a major carrier of S1P in the serum, but whether HDL-associated S1P directly mediates survival in a preparation composed exclusively of cardiomyocytes has not been demonstrated. Accordingly, we tested the hypothesis that signal activation and survival during simulated ischemia-reperfusion injury in response to HDL require lipoprotein-associated S1P. As a model, we used adult mouse cardiomyocytes subjected to hypoxia-reoxygenation. Cells were treated or not with autologous mouse HDL, which significantly increased myocyte viability as measured by trypan blue exclusion. This survival effect was abrogated by the S1P(1) and SIP(3) receptor antagonist VPC 23019. The selective S1P(3) antagonist CAY10444, the G(i) antagonist pertussis toxin, the MEK (MAPK/ERK) kinase inhibitor PD-98059, and the phosphoinositide-3 kinase inhibitor wortmannin also inhibited the prosurvival effect of HDL. We observed that HDL activated both Akt (protein kinase B) and the MEK1/2-ERK1/2 pathway and also stimulated phosphorylation of glycogen synthase kinase-3beta. ERK1/2 activation was through an S1P(1) subtype receptor-G(i) protein-dependent pathway, whereas the activation of Akt was inhibited by CAY10444, indicating mediation by S1P(3) subtype receptors. We conclude that HDL, via its cargo of S1P, can directly protect cardiomyocytes against simulated oxidative injury in the absence of vascular effects and that prosurvival signal activation is dependent on both S1P(1) and S1P(3) subtype receptors.
Tao
Rong
R
Veterans Affairs Medical Center and Department of Medicine, University of California, San Francisco, USA.
Hoover
Holly E
HE
Honbo
Norman
N
Kalinowski
Mikaila
M
Alano
Conrad C
CC
Karliner
Joel S
JS
Raffai
Robert
R
D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004195:Disease Models, Animal; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000502:physiology; D008075:Lipoproteins, HDL / Q000494:pharmacology*; D008246:Lysophospholipids / Q000502:physiology*; D048369:MAP Kinase Kinase 1 / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D048052:Mitogen-Activated Protein Kinase 3 / Q000502:physiology; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000473:pathology; D018384:Oxidative Stress / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000502:physiology
D008075:Lipoproteins, HDL; D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D051057:Proto-Oncogene Proteins c-akt; D048052:Mitogen-Activated Protein Kinase 3; D048369:MAP Kinase Kinase 1; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D013110:Sphingosine