IL-6 enhances the phagocytic function of mouse alveolar macrophages by activating the JAK2/STAT3 signaling pathway / 细胞与分子免疫学杂志

Objective To investigate the effect of interleukin-6 (IL-6) on the phagocytosis of MH-S alveolar macrophages and its related mechanisms. Methods A mouse acute lung injury (ALI) model was constructed by instilling lipopolysaccharide (LPS) into the airway. ELISA was used to detect the content of IL-6 in bronchoalveolar lavage fluid (BALF). In vitro cultured MH-S cells, in the presence or absence of signal transducer and activator 3 of transcription(STAT3) inhibitor Stattic (5 μmol/L), IL-6 (10 ng/mL~500 ng/mL) was added to stimulate for 6 hours, and then incubated with fluorescent microspheres for 2 hours. The phagocytosis of MH-S cells was detected by flow cytometry. Western blot analysis was used to detect the expression levels of phosphorylated Janus kinase 2 (p-JAK2), phosphorylated STAT3 (p-STAT3), actin-related protein 2 (Arp2) and filamentous actin (F-actin). Results The content of IL-6 in BALF was significantly increased after the mice were injected with LPS through the airway. With the increase of IL-6 stimulation concentration, the phagocytic function of MH-S cells was enhanced, and the expression levels of Arp2 and F-actin proteins in MH-S cells were increased. The expression levels of p-JAK2 and p-STAT3 proteins increased in MH-S cells stimulated with IL-6(100 ng/mL). After blocking STAT3 signaling, the effect of IL-6 in promoting phagocytosis of MH-S cells disappeared completely, and the increased expression of Arp2 and F-actin proteins in MH-S cells induced by IL-6 was also inhibited. Conclusion IL-6 promotes the expression of Arp2 and F-actin proteins by activating the JAK2/STAT3 signaling pathway, thereby enhancing the phagocytic function of MH-S cells.

SCF/c-Kit signaling promotes invasion of T24 cells via PI3K pathway / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the role of SCF/c-Kit signaling in the invasion of bladder cancer T24 cells.</p><p><b>METHODS</b>Western blotting was used to detect the expression of c-Kit and PI3K pathway activation stimulated by stem cell factor (SCF) in T24 cells. The invasiveness of T24 cells before and after SCF stimulation and Wortmannin (aspecific PI3K inhibitor) treatment was evaluated using Transwell invasion assay (direct and indirect counting methods).</p><p><b>RESULTS</b>T24 cells expressed c-Kit protein and showed obvious Akt phosphorylation after stimulation with SCF (1 ng/ml) for 24 h. Compared to the control group, SCF stimulation (1 ng/ml) caused a greater number of T24 cells to migrate through the polycarbonate film (P<0.01), and this effect was blocked by the application of Wortmannin before the stimulation.</p><p><b>CONCLUSION</b>SCF/c-Kit signaling promotes the invasiveness of T24 cells, and this effect is mediated by the PI3K pathway.</p>