title: EXTENDED CYTOPROTECTIVE EFFECT OF AUTOPHAGY IN THE LATE STAGES OF SEPSIS AND FLUCTUATIONS IN SIGNAL TRANSDUCTION PATHWAYS IN A RAT EXPERIMENTAL MODEL OF KIDNEY INJURY.
abstract: The impact of a potential autophagy (LC3a/b) deregulation in hyper and in hypo stages during sepsis-induced kidney injury and the temporal profile of phosphorylated extracellular signal-related kinase, P38 (pP38), Akt (pAKT), and 13-3-3β protein were investigated in the current study, using a rat cecal ligation and puncture (CLP) model, by means of flow cytometry and immunohistochemistry. Cell viability was assessed by protein C zymogen concentrate (PC), 7-aminoactinomycin D (7-AAD) staining and inflammation by S100 protein immunostaining. The impact of reduced kidney inflammation in autophagy was assessed by PC administration, an anti-inflammatory and cytoprotective substance. Sepsis induction increased LC3a/b expression, which presented two peaks at 6 and 36 h after CLP, both in the percentage of positive cells (P = 0.024, P = 0.025, respectively) and in fluorescence intensity. At 6 h when inflammation was already apparent, LC3a/b increase was escorted by phosphorylated extracellular signal-related kinase stimulation and high cell viability (65%), designating autophagy as a cytoprotective mechanism against microbial infection. The phosphorylation of P38 was delayed to 12 h after CLP, when autophagy was reduced. pAkt and 14-3-3β expression was stimulated between 6 and 36 h after CLP, although a slight inhibition of pAkt within each cell was detected (lower MnIX value). During the second peak, inflammation was intensified, necrosis was significantly increased with LC3a/b+/7-AAD + cells to present a 1.5-fold increase. Protein C zymogen concentrate administration declined autophagy at 6 and 36 h after CLP and reduced necrosis, whereas double positive LC3a/b and 7-AAD cells were increased by 1.68 and 2.78-fold, respectively. These data open new prospectives in sepsis treatment, since they further support that autophagy represents a cytoprotective mechanism triggered by stress conditions, rather than an alternative cell death pathway.
authors.affiliation: *Laboratory of Surgical Research, 1st Department of Propaedeutic Surgery, University of Athens Hippocration Hospital †Histopathological Diagnosis, Soutsou, Athens ‡Experimental Research Center ELPEN Pharmaceuticals, Pikermi §1st Department of Propaedeutic Surgery, University of Athens Hippocration Hospital, Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Karagiannidis
authors.forename: Agapi
authors.initials: A
authors.lastname: Kataki
authors.forename: Georgia
authors.initials: G
authors.lastname: Glustianou
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Memos
authors.forename: Apostolos
authors.initials: A
authors.lastname: Papalois
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Alexakis
authors.forename: George C
authors.initials: GC
authors.lastname: Zografos
authors.forename: Manoussos M
authors.initials: MM
authors.lastname: Konstadoulakis
mesh_terms: D058186:Acute Kidney Injury / Q000503:physiopathology*; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001343:Autophagy / Q000502:physiology*; D002432:Cecum / Q000503:physiopathology; D002478:Cells, Cultured; D003609:Dactinomycin / Q000031:analogs & derivatives / Q000378:metabolism; D005434:Flow Cytometry; D007150:Immunohistochemistry; D007249:Inflammation / Q000503:physiopathology*; D008026:Ligation; D008297:Male; D008962:Models, Theoretical; D051381:Rats; D017208:Rats, Wistar; D018805:Sepsis / Q000503:physiopathology*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D003609:Dactinomycin; C025942:7-aminoactinomycin D