Role of PI3K/Akt signaling pathway in mitochondrial fission in endotoxin-challenged alveolar type Ⅱ epithelial cells of rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of phosphatidylinositol 3-kinase/serine-threonine kinase(PI3K/Akt) signaling pathway in mitochondrial fission in endotoxin-challenged alveolar type Ⅱ epithelial cells of rats.Methods Rat alveolar type Ⅱ epithelial cells CCL-149 were seeded in 6-well plates at a density of 2×105 cells/ml.CCL-149 cells were divided into 6 groups (n =10 each) using a random number tablecontrol group (group C),lipopolysaccharide (LPS) group (group L),LPS plus CO-releasing molecule-2 (CORM-2) group (group L+CO),LPS plus PI3K inhibitor LY294002 group (group L+LY),LPS plus iCORM-2 group (group L+iCO) and LPS plus dimethyl sulfoxide (DMSO) group (group L+D).CCL149 cells were stimulated with 10 μg/ml LPS for 24 h in L,L+CO,L+LY,L+iCO and L+D groups.CORM-2 100 μmol,LY294002 25 μg and iCORM-2 100 μmol were added at 1 h before stimulation with LPS in L+CO,L+LY and LPS+iC0 groups,respectively.In group L+D,0.1％ DMSO 100 μmol was added at 1 h before stimulation with LPS.After the end of incubation,the concentrations of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the culture medium were determined by enzyme-linked immunosorbent assay,and the expression of phosphorylated-Akt (p-Akt),heme oxygenase-1 (HO-1),dynamin-related protein 1 (Drpl) and fissionl (Fisl) was detected by Western blot.Results Compared with group C,IL-6 and TNF-α concentrations in the culture medium were significantly increased,and the expression ofp-Akt,HO-1,Drp1and FIS1 was up-regulated in L,L+CO,L+LY,L+iCO and L+D groups (P＜0.05).Compared with group L,IL-6 and TNF-α concentrations in the culture medium were significantly decreased,the expression of p-Akt and HO-1 was up-regulated,and the expression of Drp1 and Fis1 was down-regulated in group L+CO,and IL-6 and TNF-α concentrations in the culture medium were significantly increased,the expression of p-Akt and HO-l was down-regulated,and the expression of Drpl and Fisl was up-regulated in group L+LY (P＜0.05).Conclusion Activation of PI3K/Akt signaling pathway can inhibit mitochondrial fission in endotoxin-challenged alveolar type Ⅱ epithelial cells of rats.