GSE108864
Long noncoding RNA Hoxb3os is dysregulated in autosomal dominant polycystic kidney disease and regulates mTOR signaling
Autosomal dominant polycystic kidney disease (ADPKD) is a debilitating disease that is characterized by the accumulation of numerous fluid-filled cysts in the kidney. ADPKD is primarily caused by mutations in two genes, PKD1 and PKD2. Long noncoding RNAs (lncRNA) – defined by a length >200 nucleotides and absence of a long open reading frame – have recently emerged as epigenetic regulators of development and disease; however, their involvement in PKD has not been explored previously. Here, we performed deep RNA sequencing to identify lncRNAs that are dysregulated in two orthologous mouse models of ADPKD (kidney-specific Pkd1 and Pkd2 mutant mice). We identified a kidney- specific, evolutionarily-conserved lncRNA called Hoxb3os that was downregulated in cystic kidneys from Pkd1 and Pkd2 mutant mice. The human ortholog HOXB3-AS1 was downregulated in cystic kidneys from ADPKD patients. Hoxb3os was 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 utilized CRISR/Cas9 to knockout its expression in mIMCD3 cells. Deletion of Hoxb3os resulted in increased phosphorylation of mTOR and its downstream targets, including p70 S6 kinase, ribosomal protein S6, and the translation repressor 4E-BP1. Consistent with activation of mTORC1 signaling, Hoxb3os mutant cells displayed increased mitochondrial respiration. The Hoxb3os mutant phenotype was partially rescued upon re- expression of Hoxb3os in knockout cells. These findings identify Hoxb3os as a novel lncRNA that is downregulated in ADPKD and regulates mTOR signaling and mitochondrial respiration. Overall design: Expression profiling by sequencing in primary kidney and cultured cells.