title: Impaired intracellular signaling, myeloperoxidase release and bactericidal activity of neutrophils from patients with alcoholic cirrhosis.
abstract: OBJECTIVE
  Myeloperoxidase exocytosis and production of hydrogen peroxide via the neutrophil superoxide-generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase contribute to efficient elimination of bacteria. Cirrhosis impairs immune functions and increases susceptibility to bacterial infection. We recently showed that neutrophils from patients with decompensated alcoholic cirrhosis exhibit a severe impairment of formylpeptide receptor (fPR)-mediated intracellular signaling and superoxide production. Here, we performed ex vivo studies with these patients' neutrophils to further investigate myeloperoxidase release, bactericidal capacity and signaling events following fPR stimulation by the formylpeptide formyl-met-leu-phe (fMLP).
  
  
  METHODS
  Myeloperoxidase release was studied by measuring extracellular myeloperoxidase activity. Activation of signaling effectors was studied by Western blot and their respective contribution to myeloperoxidase release studied using pharmacological antagonists.
  
  
  RESULTS
  fMLP-induced myeloperoxidase release was strongly impaired in patients' neutrophils whereas the intracellular myeloperoxidase stock was unaltered. The fMLP-induced phosphorylation of major signaling effectors, AKT, ERK1/2 and p38-MAP-Kinases, was also strongly deficient despite a similar expression of signaling effectors or fPR. However, based on effector inhibition in healthy neutrophils, AKT and p38-MAPK but not ERK1/2 upregulated fMLP-induced myeloperoxidase exocytosis. Interestingly, patients' neutrophils exhibited a defective bactericidal capacity that was reversed ex vivo by the TLR7/8 agonist CL097, through potentiation of the fMLP-induced AKT/p38-MAPK signaling axis and myeloperoxidase release.
  
  
  CONCLUSIONS
  We provide first evidence that neutrophils from patients with decompensated alcoholic cirrhosis exhibit a deficient AKT/p38-MAPK signaling, myeloperoxidase release and bactericidal activity, which can be reversed via TLR7/8 activation. These defects, together with the previously described severe deficient superoxide production, may increase cirrhotic patients' susceptibility to bacterial infections.
authors.affiliation: INSERM UMRS-1149, Faculté de Médécine X. Bichat, 75018 Paris, France; CNRS ERL 8252, Centre de Recherche sur l'Inflammation, 75018 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX, 75018 Paris, France; Université de Batna, Faculté des Sciences, Département de Biologie, Algeria.
authors.forename: Abdelali
authors.initials: A
authors.lastname: Boussif
authors.affiliation: INSERM UMRS-1149, Faculté de Médécine X. Bichat, 75018 Paris, France; CNRS ERL 8252, Centre de Recherche sur l'Inflammation, 75018 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX, 75018 Paris, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Rolas
authors.affiliation: INSERM UMRS-1149, Faculté de Médécine X. Bichat, 75018 Paris, France; CNRS ERL 8252, Centre de Recherche sur l'Inflammation, 75018 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX, 75018 Paris, France; Département d'Anesthésie Réanimation, Hôpital Beaujon, APHP, 92118 Clichy, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Weiss
authors.affiliation: Laboratoire de Biochimie Appliquée, Département de Biochimie, Faculté des Sciences de la Nature et de Vie, Université Ferhat Abbas, Sétif 1, Algeria.
authors.forename: Hamama
authors.initials: H
authors.lastname: Bouriche
authors.affiliation: INSERM UMRS-1149, Faculté de Médécine X. Bichat, 75018 Paris, France; CNRS ERL 8252, Centre de Recherche sur l'Inflammation, 75018 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX, 75018 Paris, France; Département Hospitalo-Universitaire (DHU) Unity, Service d'Hépatologie, Hôpital Beaujon, APHP, 92118 Clichy, France.
authors.forename: Richard
authors.initials: R
authors.lastname: Moreau
authors.affiliation: INSERM UMRS-1149, Faculté de Médécine X. Bichat, 75018 Paris, France; CNRS ERL 8252, Centre de Recherche sur l'Inflammation, 75018 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'excellence INFLAMEX, 75018 Paris, France. Electronic address: axel.perianin@inserm.fr.
authors.forename: Axel
authors.initials: A
authors.lastname: Périanin
mesh_terms: D015153:Blotting, Western; D005260:Female; D006801:Humans; D008104:Liver Cirrhosis, Alcoholic / Q000201:enzymology* / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D009195:Peroxidase
keywords: Exocytosis; Hepatitis; Host-defence; Phagocytes; Reactive oxygen species; Signaling