Abstract: TH-PO338
The Role of Poly (ADP-Ribose) Polymerase 1 in Vasopressin-Mediated AQP2 Expression
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Basic
November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid‚ Electrolyte‚ and Acid-Base Disorders
- 1001 Fluid‚ Electrolyte‚ and Acid-Base Disorders: Basic
Authors
- Jang, Hyo-Ju, Kyungpook National University School of Medicine, Daegu, Korea (the Republic of)
- Park, Euijung, National Institutes of Health, Bethesda, Maryland, United States
- Jung, Hyun Jun, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Kwon, Tae-Hwan, Kyungpook National University School of Medicine, Daegu, Korea (the Republic of)
Background
Poly(ADP-ribosy)lation (PARylation) mediated by poly(ADP-ribose) polymerases (PARPs), catalyzes the transfer of ADP-ribose from NAD+ molecules to acceptor proteins. We previously demonstrated that tankyrase, one of PARPs family, regulates AQP2 expression via β-catenin-mediated transcription. We aimed to examine the role of PARP1, the most abundant protein in the PARPs family, in the AQP2 regulation.
Methods
1) immunoblotting for PARP1 in mpkCCDc14 cells; 2) pulldown assay of biotin-conjugated NAD+ and immunoprecipitation (IP) assay using poly(ADP-ribose) (PAR) antibody; 3) qRT-PCR and immunoblotting for AQP2; and 4) bioinformatics for elucidating PARP1 substrates and interacting proteins in kidney collecting duct (CD) cells.
Results
Immunoblots showed that PARP1 cleavage (both 89 kDa and 25 kDa) was induced by dDAVP (10-9 M) treatment in whole cell lysate, nuclear, and cytoplasm extracts of mpkCCDc14 cells, respectively. dDAVP (10-9 M, 24 h) increased the abundance of total PARylated proteins in biotin-NAD+ pulldown and IP assays of PAR in mpkCCDc14 cells. dDAVP-induced AQP2 mRNA and protein expression was significantly attenuated in mpkCCDc14 cells with siRNA-mediated PARP1 knockdown. Since PARP1 cleavage induced by dDAVP was not affected despite PARP1 knockdown, PARP1 cleavage is unlikely to be involved in AQP2 regulation. In contrast to PARP1 knockdown, inhibition of PARP1 activity by PARP inhibitor (PJ34) did not affect dDAVP-induced AQP2 mRNA and protein upregulation, suggesting that PARylation mediated by PARP1 was not involved in AQP2 regulation. Bioinformatics study revealed 408 proteins interacting with PARP1 and 763 substrates proteins of PARP1 in the kidney CD cells. Among them, 604 proteins were mapped on the vasopressin V2 receptor (V2R) signaling pathway. β-catenin, which is phosphorylated (S552) by dDAVP, was identified as the PARP1 interacting protein mapped on the V2R signaling. Immunoblotting demonstrated that dDAVP-induced pS552-β-catenin expression in the whole cell lysate as well as nucleus in mpkCCDc14 cells was significantly attenuated in the presence of PARP1 knockdown.
Conclusion
PARP1 plays a role in vasopressin-mediated AQP2 regulation via β-catenin, as the vasopressin-responsive interacting protein of PARP1, but unlikely through the PARylation of proteins and/or PARP1 cleavage in the kidney CD cells.
Funding
- Government Support – Non-U.S.