Activin and activin receptors in the normal urinary bladder: immunohistochemistry, in situ hybridization, and RT-PCR

A novel role for follistatin in hypersensitivity following cystitis

AIMS

Previous studies have shown that the activin-binding protein follistatin reduces inflammation in several mouse models of colitis. To determine whether follistatin also has a beneficial effect following bladder inflammation, we induced cystitis in mice using cyclophosphamide (CYP) and examined the relationship between bladder hypersensitivity and bladder follistatin expression.

METHODS

Adult female C57BL/6 mice were treated with CYP (100 mg/kg) or vehicle (saline) three times over 5 days. Bladder hypersensitivity was assessed by recording the visceromotor response (VMR) to urinary bladder distension and in vitro single-fiber bladder afferent recording. Follistatin gene expression was measured using qRT-PCR. Immunohistochemistry was employed for further characterization.

RESULTS

Bladder hypersensitivity was established by day 6 and persisted to day 14 in CYP-treated mice. On day 14, hypersensitivity was accompanied by increases in follistatin gene expression in the bladder. Follistatin-like immunoreactivity colocalized with laminin, and the percentage of structures in the lamina propria that were follistatin-positive was increased in CYP-treated mice. Exogenous follistatin increased VMR and afferent responses to bladder distension in CYP- but not vehicle-treated mice.

CONCLUSIONS

Chronic bladder pain following CYP treatment is associated with increased follistatin expression in the bladder. These results suggest a novel, pro-nociceptive role for follistatin in cystitis, in contrast with its proposed therapeutic role in colitis. This protein has exciting potential as a biomarker and therapeutic target for bladder hypersensitivity. Neurourol. Urodynam. 36:286-292, 2017. © 2015 Wiley Periodicals, Inc.

Molecular profiling of bladder cancer: involvement of the TGF-beta pathway in bladder cancer progression

A human bladder cancer model of nine cell sublines derived from the BL17/2 cell line was used to evaluate genes related to disease progression. Molecular profiling of sublines that were non-tumorigenic and invasive in nude mice was performed and identified 1367 differentially-expressed genes. Quantitative real-time PCR analysis of six transforming growth factor-beta (TGF-beta) pathway genes using the entire panel of nine cell lines was performed. Bone morphogenetic protein-2 expression was significantly associated with in vivo tumorigenicity of the cell lines (p=0.0228, Mann-Whitney); inhibin-betaB was related to their invasiveness (p=0.0468, Mann-Whitney). Analysis of conditioned medium showed TGF-beta1 production to be significantly associated with the phenotype of the cell line. The study shows the possible involvement of the TGF-beta pathway in bladder cancer progression.