PI3K/Akt pathway is involved in the activation of RAW 264.7 cells induced by hydroxypropyltrimethyl ammonium chloride chitosan.

We previously demonstrated that 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) promoted the production of nitric oxide (NO) and proinflammatory cytokines by activating the mitogen-activated protein kinases (MAPK) and Janus kinase (JAK)/STAT pathways in RAW 264.7 cells, indicating good immunomodulatory activity of HACC. In this study, to further investigate the immunomodulatory mechanisms of HACC, we determined the roles of phosphatidylinositol 3-kinase (PI3K)/Akt, activating protein (AP-1) and nuclear factor kappa B (NF-κB) in HACC-induced activation of RAW 264.7 cells by the western blotting. The results suggest that HACC promoted the phosphorylation of p85 and Akt. Furthermore, c-Jun and p65 were also increased after the treatment of RAW 264.7 cells with HACC, indicating the translocation of NF-κB and AP-1 from cytoplasm to nucleus. In addition, as scanning electron microscopy (SEM) analysis shows, the cell morphology changed after HACC treatment. These findings indicate that HACC activated MAPK, JAK/STAT, and PI3K/Akt signaling pathways dependent on AP-1 and NF-κB activation in RAW 264.7 cells, ultimately leading to the increase of NO and cytokines. [ABSTRACT FROM AUTHOR]