title: 5'-AMP-activated protein kinase activation prevents postischemic leukocyte-endothelial cell adhesive interactions.
abstract: Preconditioning (PC) with nitric oxide (NO) donors or agents that increase endothelial NO synthase (eNOS) activity 24 h before ischemia-reperfusion (I/R) prevents postischemic leukocyte rolling (LR) and stationary leukocyte adhesion (LA). Since 5'-AMP-activated protein kinase (AMPK) phosphorylates eNOS at Ser1177, resulting in activation, we postulated that AMPK activation may trigger the development of a preconditioned anti-inflammatory phenotype similar to that induced by NO donors. Wild-type (WT) C57BL/6J and eNOS(-/-) mice were treated with the AMPK agonist 5-aminoimidazole-4-carboxamide 1-beta-d-furanoside (AICAR) 30 min (early AICAR PC) or 24 h (late AICAR PC) before I/R; LR and LA were quantified in single postcapillary venules in the jejunum using intravital microscopy. I/R induced comparable marked increases in LR and LA in WT and eNOS(-/-) mice relative to sham-operated (no ischemia) animals. Late AICAR PC prevented postischemic LR and LA, whereas early AICAR PC prevented LA in WT mice. Late AICAR PC was ineffective in preventing I/R-induced LR but not LA in the eNOS(-/-) mice, and the same pattern was seen in WT animals treated with the NOS inhibitor N(omega)-nitro-l-arginine. Early AICAR PC remained effective in preventing LA in eNOS(-/-) mice. Our results indicate that both early and late PC with an AMPK agonist produces an anti-inflammatory phenotype in postcapillary venules. Since the protection afforded by late AICAR PC on postischemic LR was prevented by NOS inhibition in WT mice and absent in eNOS-deficient mice, it appears that eNOS triggers this protective effect. In stark contrast, antecedent AMPK activation prevented I/R-induced LA by an eNOS-independent mechanism.
authors.affiliation: Dept. of Medical Pharmacology and Physiology, Univ. of Missouri-Columbia, 1 Hospital Dr., Columbia, MO 65212, USA. korthuisr@health.missouri.edu
authors.forename: F Spencer
authors.initials: FS
authors.lastname: Gaskin
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kamada
authors.forename: Mozow
authors.initials: M
authors.lastname: Yusof
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Korthuis
mesh_terms: D055372:AMP-Activated Protein Kinases; D000620:Aminoimidazole Carboxamide / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects*; D042783:Endothelial Cells / Q000187:drug effects*; D004789:Enzyme Activation; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D007962:Leukocytes / Q000187:drug effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009097:Multienzyme Complexes / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012265:Ribonucleotides / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D009097:Multienzyme Complexes; D012265:Ribonucleotides; D000620:Aminoimidazole Carboxamide; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide