Effect of Agonist and Inhibitor of PI3K/AKT on Inflammatory Response in Macrophages / 胃肠病学

ABSTRACT

Phosphoinositide 3-kinase/serine-threonine kinase (PI3K/AKT)has been found playing an important role in the pathogenesis of severe acute pancreatitis (SAP)in recent years,but the underlying mechanism has not been clarified.Aims:To investigate the role of PI3K/AKT in regulating the inflammatory response in SAP by evaluating the effect of insulin-like growth factor-Ⅰ (IGF-Ⅰ)and wortmannin,the agonist and inhibitor of PI3K/AKT on Toll-like receptor 4 (TLR4)signaling pathway in macrophage cell line RAW264.7.Methods:RAW264.7 cells were treated with different concentrations of lipopolysaccharide (LPS ), IGF-Ⅰ and wortmannin, respectively, and cell viability was determined by CCK-8 assay.RAW264.7 cells were divided into blank control group (no treatment),LPS group (LPS 1 μg/mL),IGF-Ⅰ group (IGF-Ⅰ 100 ng/mL +LPS 1 μg/mL),wortmannin group (wortmannin 100 nmol/L +LPS 1 μg/mL)and IGF-Ⅰ +wortmannin group (wortmannin 100 nmol/L +IGF-Ⅰ 100 ng/mL +LPS 1 μg/mL).Protein expressions of tumor necrosis factor-α(TNF-α)and interleukin-6 (IL-6)were detected by ELISA;mRNA expressions of TLR4,myeloid differentiation factor 88 (MyD88),AKT,PI3K,p38 mitogen-activated protein kinase (p38MAPK)and nuclear factor-κB (NF-κB)were determined by real-time PCR.Results:After treated with LPS,IGF-Ⅰand wortmannin, respectively,no differences in cell viability of RAW264.7 cells were found between different concentrations groups (P>0.05).Protein expressions of TNF-αand IL-6 in LPS,IGF-Ⅰ,wortmannin and IGF-Ⅰ +wortmannin groups were significantly higher than those in blank control group (P<0.05 ).Protein expressions of TNF-αand IL-6 in wortmannin group were significantly lower than those in LPS and IGF-Ⅰ groups (P<0.05),and those in IGF-Ⅰ+wortmannin group were significantly lower than those in IGF-Ⅰ group (P<0.05).In LPS group,mRNA expressions of AKT and PI3K as well as TLR4 and its downstream molecules MyD88,p38MAPK and NF-κB were significantly higher than those in blank control group (P <0.05 ).Expressions of all above-mentioned mRNAs in IGF-Ⅰ group were further increased and significantly higher than those in LPS group (P<0.05).Expressions of all above-mentioned mRNAs in wortmannin group were significantly lower than those in LPS and IGF-Ⅰ groups (P<0.05 ),and those in IGF-Ⅰ+wortmannin group were significantly higher than those in wortmannin group (P<0.05),but significantly lower than those in IGF-Ⅰ group (P<0.05).Conclusions:PI3K/AKT might regulate TLR4 signaling pathway and its downstream molecules in macrophages, thereby affects the expressions of inflammatory cytokines and being involved in the pathogenesis of inflammatory response in SAP.