Kidney Week

Abstract: TH-OR046

The Long Noncoding RNA Hoxb3os Is Dysregulated in Autosomal Dominant Polycystic Kidney Disease and Regulates mTOR Signaling

Session Information

• Cystic Kidney Diseases: Genes, Mechanisms, Interventions
  November 02, 2017 | Location: Room 390, Morial Convention Center
  Abstract Time: 05:30 PM - 05:42 PM

Category: Genetic Diseases of the Kidney

• 801 Cystic Kidney Diseases

Authors

• Aboudehen, Karam S., University of Minnesota, Minneapolis, Minnesota, United States

Karam S. Aboudehen, PhD

• Kanchwala, Mohammed Shabbir, UT Southwestern Medical Center, Dallas, Texas, United States

Mohammed Shabbir Kanchwala,

• Farahani, Shayan A., University of Minnesota, Minneapolis, Minnesota, United States

Shayan A. Farahani,

• Vrba, Sophia M., University of Minnesota, Minneapolis, Minnesota, United States

Sophia M. Vrba,

• Chan, Siu Chiu, University of Minnesota, Minneapolis, Minnesota, United States

Siu Chiu Chan,

• Avdulov, Svetlana, University of Minnesota, Minneapolis, Minnesota, United States

Svetlana Avdulov,

• Mickelson, Alan, University of Minnesota, Minneapolis, Minnesota, United States

Alan Mickelson,

• Patel, Vishal, University of Texas Southwestern Medical Center, Dallas, Texas, United States

Vishal Patel,

• Xing, Chao, University of Texas Southwestern Medical Center, Dallas, Texas, United States

Chao Xing,

• Igarashi, Peter, University of Minnesota, Minneapolis, Minnesota, United States

Peter Igarashi,

Background

Polycystic kidney disease (PKD) is a debilitating disease that is characterized by the accumulation of numerous fluid-filled cysts in the kidney. Autosomal dominant polycystic kidney disease (ADPKD), is primarily caused by mutations in two genes, PKD1 and PKD2. The pathophysiology of PKD is incompletely understood, and no FDA-approved treatment currently exists. Long noncoding RNAs (lncRNAs) are single-stranded RNA molecules that are >200 nucleotides in length, lack a long open-reading-frame, and have recently emerged as epigenetic regulators of development and disease; however, their involvement in PKD has not been explored previously.

Results

Here, we performed deep RNA sequencing to identify lncRNAs that are deregulated in two orthologous mouse models of ADPKD (kidney-specific Pkd1 and Pkd2 mutant mice). We identified a kidney-specific and highly conserved lncRNA, called Hoxb3os, that was down-regulated in cystic kidneys from Pkd1 and Pkd2 mutant mice as well as in a Pkd2 mutant renal cell line. Its human ortholog HOXB3-AS was down-regulated in kidneys from PKD patients. Hoxb3os was normally highly expressed in renal tubules in adult wild-type mice, whereas its expression was lost in the cyst epithelium of mutant mice. To investigate the function of Hoxb3os, we performed RNA-seq analysis on Hoxb3os knockdown mIMCD3 cells. Knockdown of Hoxb3os resulted in >2-fold dysregulation of 77 genes, 40 of which were similarly dysregulated in PKD mouse models. Pathway analysis suggested that Hoxb3os activated mTOR signaling, a pathway that has been implicated in PKD. Consistent with this result, ablation of Hoxb3os in mIMCD3 cells with CRISPR/Cas9 resulted in hyperactivation of mTOR signaling, as evidenced by enhanced phosphorylation of mTOR and ribosomal protein S6. Compared to wild-type cells, Hoxb3os knockout cells had increased rates of cell proliferation. Conversely, overexpression of Hoxb3os in wild-type mIMCD3 cells decreased phosphorylation of mTOR and S6. Collectively, these findings identify Hoxb3os as a novel lncRNA that is dysregulated in human and mouse PKD.

Conclusion

Down-regulation of Hoxb3os may underlie transcriptional abnormalities and hyperactivation of mTOR signaling in PKD.

Funding

• NIDDK Support