title: The central role of adenosine in statin-induced ERK1/2, Akt, and eNOS phosphorylation.
abstract: Statins activate phosphatidylinositol-3-kinase, which activates ecto-5'-nucleotidase and phosphorylates 3-phosphoinositide-dependent kinase-1 (PDK-1). Phosphorylated (P-)PDK-1 phosphorylates Akt, which phosphorylates endothelial nitric oxide synthase (eNOS). We asked if the blockade of adenosine receptors (A(1), A(2A), A(2B), or A(3) receptors) could attenuate the induction of Akt and eNOS by atorvastatin (ATV) and whether ERK1/2 is involved in the ATV regulation of Akt and eNOS. In protocol 1, mice received intraperitoneal ATV, theophylline (TH), ATV + TH, or vehicle. In protocol 2, mice received intraperitoneal injections of ATV, U0126 (an ERK1/2 inhibitor), ATV + U0126, or vehicle; 8 h later, hearts were assessed by immunoblot analysis. In protocol 3, mice received intraperitoneal ATV alone or with 8-sulfophenyltheophylline (SPT); 1, 3, and 6 h after injection, hearts were assessed by immunoblot analysis. In protocol 4, mice received intraperitoneal ATV alone or with SPT, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), 1,3,7-trimethyl-8-(3-chlorostyryl)xanthine (CSC), alloxazine, or MRS-1523; 3 h after injection, hearts were assessed by immunoblot analysis. ATV increased P-ERK, P-PDK-1, Ser(473) P-Akt, Thr(308) P-Akt, and P-eNOS levels. TH blocked ATV-induced increases in P-ERK, Ser(473) P-Akt, Thr(308) P-Akt, and P-eNOS levels without affecting the induction of P-PDK-1 by ATV. U0126 blocked the ATV induction of Ser(473) P-Akt and Thr(308) P-Akt while attenuating the induction of P-eNOS. A detectable increase in P-ERK, Ser(473) P-Akt and P-eNOS was seen 3 and 6 h after injection but not at 1 h. DPCPX, CSC, and alloxazine partially blocked the ATV induction of P-ERK, Ser(473) P-Akt, and P-eNOS. In conclusion, blockade of adenosine A(1), A(2A), and A(2B) receptors but not A(3) receptors inhibited the induction of Akt and eNOS by statins. Adenosine was required for ERK1/2 activation by statins, which resulted in Akt and eNOS phosphorylation.
authors.affiliation: Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555-0553, USA.
authors.forename: Ramanna
authors.initials: R
authors.lastname: Merla
authors.forename: Yumei
authors.initials: Y
authors.lastname: Ye
authors.forename: Yu
authors.initials: Y
authors.lastname: Lin
authors.forename: Saraswathy
authors.initials: S
authors.lastname: Manickavasagam
authors.forename: Ming-He
authors.initials: MH
authors.lastname: Huang
authors.forename: Regino J
authors.initials: RJ
authors.lastname: Perez-Polo
authors.forename: Barry F
authors.initials: BF
authors.lastname: Uretsky
authors.forename: Yochai
authors.initials: Y
authors.lastname: Birnbaum
mesh_terms: D015720:5'-Nucleotidase / Q000378:metabolism; D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D000069059:Atorvastatin; D002070:Butadienes / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006538:Heptanoic Acids / Q000494:pharmacology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011758:Pyrroles / Q000494:pharmacology; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D018047:Receptors, Purinergic P1 / Q000378:metabolism; D013806:Theophylline / Q000494:pharmacology
chemical_list: D002070:Butadienes; D004791:Enzyme Inhibitors; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D009570:Nitriles; D010726:Phosphodiesterase Inhibitors; D011758:Pyrroles; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D018047:Receptors, Purinergic P1; C113580:U 0126; D009569:Nitric Oxide; D000069059:Atorvastatin; D013806:Theophylline; D052250:Nitric Oxide Synthase Type III; C514862:Akt1 protein, mouse; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D048052:Mitogen-Activated Protein Kinase 3; D015720:5'-Nucleotidase; D000241:Adenosine