title: Adenosine monophosphate-activated protein kinase activation protects against sepsis-induced organ injury and inflammation.
abstract: BACKGROUND
  Mortality in sepsis is most often attributed to the development of multiple organ failure. In sepsis, inflammation-mediated endothelial activation, defined as a proinflammatory and procoagulant state of the endothelial cells, has been associated with severity of disease. Thus, the objective of this study was to test the hypothesis that adenosine monophosphate-activated protein kinase (AMPK) activation limits inflammation and endothelium activation to protect against organ injury in sepsis. 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), which is an adenosine monophosphate analog, has been used to upregulate activity of AMPK. Compound C is a cell-permeable pyrrazolopyrimidine compound that inhibits AMPK activity.
  
  
  METHODS
  Wild-type mice underwent cecal ligation and puncture (CLP) or sham surgery. Mice were randomized to vehicle, AICAR, or compound C. Mouse kidney endothelial cells were used for in vitro experiments. Renal and liver function were determined by serum cystatin C, blood urea nitrogen (BUN), creatinine, and alanine aminotransferase. Serum cytokines were measured by enzyme-linked immunosorbent assay. Microvascular injury was determined using Evans blue dye and electron microscopy. Immunohistochemistry was used to measure protein levels of phospho-AMPK (p-AMPK), microtubule-associated protein 1A/1B-light chain 3 (LC3), and intracellular adhesion molecule. LC3 levels were used as a measure of autophagosome formation.
  
  
  RESULTS
  AICAR decreased liver and kidney injury induced by CLP and minimized cytokine elevation in vivo and in vitro. CLP increased renal and hepatic phosphorylation of AMPK and autophagic signaling as determined by LC3. Inhibition of AMPK with compound C prevented CLP-induced autophagy and exacerbated tissue injury. Additionally, CLP led to endothelial injury as determined by electron microscopy and Evans blue dye extravasation, and AICAR limited this injury. Furthermore, AICAR limited CLP and lipopolysaccharide (LPS)-induced upregulation of intracellular adhesion molecule in vivo and in vitro and decreased LPS-induced neutrophil adhesion in vitro.
  
  
  CONCLUSIONS
  In this model, activation of AMPK was protective, and AICAR minimized organ injury by decreasing inflammatory cytokines and endothelial activation. These data suggest that AMPK signaling influences sepsis or LPS-induced endothelial activation and organ injury.
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Escobar
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Botero-Quintero
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Kautza
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Jason
authors.initials: J
authors.lastname: Luciano
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Patricia
authors.initials: P
authors.lastname: Loughran
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Sophie
authors.initials: S
authors.lastname: Darwiche
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Rosengart
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Surgery, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh, Pennsylvania; Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Zuckerbraun
authors.affiliation: Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania. Electronic address: gomezh@upmc.edu.
authors.forename: Hernando
authors.initials: H
authors.lastname: Gomez
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001343:Autophagy / Q000502:physiology; D002448:Cell Adhesion; D002478:Cells, Cultured; D016207:Cytokines / Q000502:physiology; D042783:Endothelial Cells / Q000502:physiology; D007249:Inflammation / Q000517:prevention & control*; D007962:Leukocytes / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009102:Multiple Organ Failure / Q000517:prevention & control*; D012265:Ribonucleotides / Q000494:pharmacology; D018805:Sepsis / Q000150:complications*
chemical_list: D016207:Cytokines; D012265:Ribonucleotides; D000620:Aminoimidazole Carboxamide; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide
keywords: AMPK; Endothelium; Energy; Inflammation; Organ injury; Sepsis