Hippo-YAP signaling pathway regulates autophagy of human periodontal ligament cells under cyclic tensile stress.

OBJECTIVES

This work aimed to investigate the molecular mechanism of cyclic tensile stress (CTS) stimulating autophagy in human periodontal ligament cells (hPDLCs).

METHODS

hPDLCs were isolated and cultured from normal periodontal tissues. hPDLCs were loaded with tensile stress by force four-point bending extender to simulate the autophagy of hPDLCs induced by orthodontic force du-ring orthodontic tooth movement. XMU-MP-1 was used to inhibit the Hippo signaling pathway to explore the role of the Hippo-YAP signaling pathway in activating hPDLC autophagy by tensile stress. The expression levels of autophagy-related genes (Beclin-1, LC3, and p62) in hPDLCs were detected by real-time quantitative polymerase chain reaction. Western blot was used to detect the expression levels of autophagy-related proteins (Beclin-1, LC3-Ⅱ/LC3-Ⅰ, and p62) and Hippo-YAP pathway proteins (active-YAP and p-YAP) in hPDLCs. Immunofluorescence was used to locate autophagy-related proteins (LC3-Ⅱand p62) and Hippo-YAP pathway proteins (active-YAP) of hPDLCs.

RESULTS

CTS-activated autophagy in hPDLCs and expression of autophagy-related proteins initially increased and then decreased; it began to increase at 30 min, peaked at 3 h, and decreased (<0.05). CTS increased the expression of active-YAP protein and decreased the expression of p-YAP protein (<0.05). When XMU-MP-1 inhibited the Hippo-YAP signaling pathway (<0.05), active-YAP protein was promoted to enter the nucleus and autophagy expression was enhanced (<0.05).

CONCLUSIONS

The Hippo-YAP signaling pathway is involved in the regulation of autophagy activation in hPDLCs under CTS.