Inhibition of Stat3 signaling pathway decreases TNF-α-induced autophagy in cementoblasts
Autophagy is a self-digestive process that eliminates impaired or aged proteins and potentially toxic intracellular components to maintain homeostasis. We previously demonstrated that TNF-α played a critical role in cementoblast differentiation, mineralization and apoptosis; however, the effect of TNF-α on cementoblast autophagy has remained unclear. In this study, an elevated immunofluorescence signal of LC3B and autophagic vacuoles, autophagosomes and autolysosomes were detected under TNF-α stimulation in OCCM-30 cells. Autophagy-related genes and proteins, Beclin-1, LC3A and Atg-5, were significantly upregulated by TNF-α in a time- and concentration-dependent manner. During this process, the activity of Stat3 was dramatically enhanced and when the activity of Stat3 was blocked by either a specific chemical inhibitor or siRNA transfection before TNF-α stimulation, the TNF-α-induced upregulation of autophagy-related genes and proteins was strongly inhibited. Our results suggest that TNF-α induced autophagy in cementoblasts was dependent, or partially dependent on the activity of Stat3 signaling pathway.
KeywordsTumor necrosis factor-α Dental cementum Cementoblast Autophagy Signal transducer and activator of transcription 3
Study design: L.L. Wang, Y.L. Wang, H. He, Z.J. Liu, Z.G. Cao and M.Y. Du. Data Collection and analysis: L.L. Wang, and Y.R. Hao. Contribution of new reagents or analytical tools: M.Y. Du. Manuscript preparation: L.L. Wang, Y.L. Wang and H. He.
This study was financially supported by grants from the National Natural Science Foundation of China (Nos. 81671020 and 81200811) and the Natural Science Foundation of Hubei Province (No. 2015CFB404)
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Conflict of interest
The authors declare that they have no conflict of interest.
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