Objective: To study the effects of cyclic mechanical stretch on the activity and expression of STAT3 in Human bronchial epithelial Cell (16HBEC).
Methods: The 16HBECs were subjected to cyclic mechanical stretch by the four-point bending system at 0.5 Hz of 1 kPa, 2 kPa, 3 kPa, 4 kPa for 30 min or for 30 min, 1 h, 3 h, and 6 h of 3 kPa respectively. The mRNA level of STAT3 was semi-quantified by RT-PCR; STAT3 protein and phosphorylated STAT3 were detected by western blot.
Results: Phosphorylation level of STAT3 Tyr705 was higher under 3 kPa cyclic mechanical stretch than the others. 3 kPa stretch phosphorylatd STAT3 Tyr705 in 16HBE cells in a time-dependent manner. The phosphorylation of STAT3-Tyr705 was significantly increased at 30 min compared with the control group (P<0.05), and reached the highest phosphorylation level at 1 h, then showed a sharp descending tendency. There was no effect of 3 kPa stretch on the phosphorylation of STAT3 Ser727, expression of STAT3 protein or mRNA levels.
Conclusion: STAT3 played an important role in the response and signal transduction of 16HBECs to the cyclic mechanical stretch stimulation through the phosphorylation of STAT3 Tyr705.