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Abstract: FR-PO307

Parathyroid Hormone (PTH) Promotes the Release of H+ by Osteoclasts via the ATF3/V-ATPase Signaling Pathway

Session Information

Category: Bone and Mineral Metabolism

  • 501 Bone and Mineral Metabolism: Basic

Author

  • Deng, Shuting, Guangdong Provincial People's Hospital, Guangzhou, Guangdong, China
Background

Persistently high levels of parathyroid hormone (PTH) promote osteolysis in patients with end-stage renal disease (ESRD). It is an important part that release of hydrogen ions (H+ ) by osteoclasts leads to hydroxyapatite crystal dissolution in osteolysis, which is closely related to the proton pump (V-ATPase) on the osteoclast membrane. Activating Transcription Factor 3 (ATF3) initiates the differentiation and activation of osteoclasts. This experiment aimed to investigate that PTH promotes the release of H+ by osteoclasts via the ATF3/V-ATPase a3 signaling pathway.

Methods

Chromatin immunoprecipitation(ChIP) assay was used to examine the binding of ATF3 and V-ATPase a3 in mouse osteoclasts. With the stimulation of PTH, we used RT-qPCR and western blot to detect the expression of ATF3, V-ATPase a3 and the expression of V-ATPase a3 which treated with silencing and overexpression of ATF3. After PTH treatment in osteoclasts, we used BCECF-AM probe to detect the pH with silencing and overexpression of ATF3, and the stronger the green fluorescence, the lower the pH, which indirectly reflected the release of H+ by osteoclasts.

Results

ChIP assay proved that ATF3 binds to the V-ATPase a3(Figure1 A-B). PTH promoted the expression of ATF3 and V-ATPase a3(Figure1 C-F), and weakened green fluorescence of the cell, increasing the release of H+ by osteoclasts. After PTH treatment in osteoclasts, silencing ATF3 can decrease the expression of V-ATPase a3 and the release of H+ by cells but enhance green fluorescence in osteoclasts (Figure2), while overexpression of ATF3 can increase the expression of V-ATPase a3.

Conclusion

ATF3 is a transcription factor of V-ATPase a3. PTH promotes the expression of ATF3 and V-ATPase a3, which then facilitates the release of H+ by osteoclasts.