Theranostics 2020; 10(18):8281-8297. doi:10.7150/thno.47315

Research Paper

RNA helicase p68 inhibits the transcription and post-transcription of Pkd1 in ADPKD

Lu Zhang1,2, Linda Xiaoyan Li1, Julie Xia Zhou1, Peter C. Harris1, James P. Calvet3, Xiaogang Li1✉

1. Department of Internal Medicine and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905.
2. Department of Nephrology, Renmin Hospital of Wuhan University, Wuhan 430060, China.
3. Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160.

This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). See http://ivyspring.com/terms for full terms and conditions.
Citation:
Zhang L, Li LX, Zhou JX, Harris PC, Calvet JP, Li X. RNA helicase p68 inhibits the transcription and post-transcription of Pkd1 in ADPKD. Theranostics 2020; 10(18):8281-8297. doi:10.7150/thno.47315. Available from http://www.thno.org/v10p8281.htm

File import instruction

Abstract

Background: Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations of the PKD1 and PKD2 genes. Dysregulation of the expression of PKD genes, the abnormal activation of PKD associated signaling pathways, and the expression and maturation of miRNAs regulates cyst progression. However, the upstream factors regulating these abnormal processes in ADPKD remain elusive.

Methods: To investigate the roles of an RNA helicase, p68, in ADPKD, we performed Western blot and qRT-PCR analysis, immunostaining and ChIP assay in cystic renal epithelium cells and tissues.

Results: We found that p68 was upregulated in cystic renal epithelial cells and tissues. p68 represses Pkd1 gene expression via transcriptional and posttranscriptional mechanisms in renal epithelial cells, in that 1) p68 binds to the promoter of the Pkd1 gene together with p53 to repress transcription; and 2) p68 promotes the expression and maturation of miR-17, miR-200c and miR-182 and via these miRNAs, post-transcriptionally regulates the expression of Pkd1 mRNA. Drosha is involved in this process by forming a complex with p68. p68 also regulates the phosphorylation and activation of PKD proliferation associated signaling and the expression of fibrotic markers in Pkd1 mutant renal epithelial cells. Silence of p68 delays cyst formation in collecting duct cell mediated 3D cultures. In addition, the expression of p68 is induced by H2O2-dependent oxidative stress and DNA damage which causes downregulation of Pkd1 transcription in cystic renal epithelial cells and tissues.

Conclusions: p68 plays a critical role in negatively regulating the expression of the PKD1 gene along with positively regulating the expression and maturation of miRNAs and activation of PKD associated signaling pathways to cause renal cyst progression and fibrosis in ADPKD.

Keywords: p68, transcription regulation, miRNA, PKD1, ADPKD