Transcriptomics Analysis of ADPKD Cysts Shows Remodeling of Purinergic Receptors in Pkd1RC/RC Mice

Document Type

Conference Proceeding

Publication Date

11-1-2023

Publication Title

J Am Soc Nephrol

Abstract

Background: Polycystic kidney diseases (PKD) are characterized by development of multiple cysts, dilations of nephron segments, which replace normal tissues and lead to kidney insufficiency.

Methods: To identify new gene pathways affected by cyst development in collecting ducts, we used a bulk RNAseq approach comparing gene expression of normal microdissected cortical collecting ducts (n=3) vs cysts (n=4) microdissected from the same Pkd1RC/RC mice.

Results: Bulk-RNA analysis identified 18,000 genes and allowed statistical comparison of over 15,000 genes. Our data reveals that although cysts originate from normal collecting ducts, cystic epithelium show 2692 down-regulated and 2278 upregulated genes (p<0.05 pAdj. FDR). Ingenuity Pathways Analysis identifies the following intracellular mechanisms mostly affected by transition: Rac and Rho signaling, fibrosis signaling, epithelial-to-mesenchymal transition, cytoskeleton rearrangement and ERK/MAPK signaling. Our previous publication reported that development of cysts in an autosomal recessive model of PKD is associated with a shift of P2Y to P2X receptor abundance. In the current study we found that in the autosomal dominant Pkd1RC/RC mice model purinergic signaling undergoes similar remodeling. The most abundant ionotropic receptors with reduced expression were P2ry2 and P2ry4, whereas ionotropic receptors P2rx5 and P2rx7 increased expression (2.88 and 1.53, log2). Additionally, analysis detected elevated abundance of P2ry6, P2ry12 and P2ry13 RNA level. We hypothesize that the physiological significance of the predominant P2X signaling in the cysts include their role in regulation of ATP release via pannexin-1 channels. Abnormal ATP accumulation in the cyst space was shown earlier to contribute in cystogenesis and we previously showed that pannexin-1 mediates ATP release to the cyst lumen. In the presented study, RNAscope confirms hyperexpression of P2rx7 mRNA in cysts. In a heterologous CHO cells system, interaction of P2X7 with pannexin-1 upregulates channel activity and both proteins co-immuno precipitate.

Conclusions: Development and establishment of ADPKD cysts involves massive transcriptome remodeling of collecting ducts which include a shift in purinergic signaling that facilitates pathogenic pannexin-1 hyperactivity.

Volume

34

First Page

556

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