Array profiling reveals contribution of Cthrc1 to growth of the denervated rat urinary bladder

Abstract

Bladder denervation and bladder outlet obstruction are urological conditions that cause bladder growth. Transcriptomic surveys in outlet obstruction have identified differentially expressed genes, but similar studies following denervation have not been done. This was addressed using a rat model in which the pelvic ganglia were cryo-ablated followed by bladder microarray analyses. At 10 days following denervation, bladder weight had increased 5.6-fold, and 2,890 mRNAs and 135 micro-RNAs (miRNAs) were differentially expressed. Comparison with array data from obstructed bladders demonstrated overlap between the conditions, and 10% of mRNAs changed significantly and in the same direction. Many mRNAs, including collagen triple helix repeat containing 1 ( Cthrc1), Prc1, Plod2, and Dkk3, and miRNAs, such as miR-212 and miR-29, resided in the shared signature. Discordantly regulated transcripts in the two models were rare, making up for <0.07% of all changes, and the gene products in this category localized to the urothelium of normal bladders. These transcripts may potentially be used to diagnose sensory denervation. Western blotting demonstrated directionally consistent changes at the protein level, with increases of, e.g., Cthrc1, Prc1, Plod2, and Dkk3. We chose Cthrc1 for further studies and found that Cthrc1 was induced in the smooth muscle cell (SMC) layer following denervation. TGF-β1 stimulation and miR-30d-5p inhibition increased Cthrc1 in bladder SMCs, and knockdown and overexpression of Cthrc1 reduced and increased SMC proliferation. This work defines common and distinguishing features of bladder denervation and obstruction and suggests a role for Cthrc1 in bladder growth following denervation.