Login to Access Video or Poster Abstract: MP17-12
Sources of Funding: Supported by NIH/NIDDK grant 1P20DK090870?03 (JAM) and 1U54DK104310 (JAM).

Introduction

A growing number of recent studies associate lower urinary tract dysfunction (LUTD) with concurrent tissue fibrosis. Other studies have described profuse inflammatory infiltrate of benign prostatic hyperplasia (BPH) tissues, and that Th2 cytokines, particularly IL-4 and IL-13, are produced and secreted by infiltrating T-cells in these tissues. Because Th2 cytokines have been shown to mediate tissue fibrosis in the lung and liver, we hypothesized that Th2 cytokines secreted by inflammatory infiltrate may promote collagen accumulation and fibrosis in the prostate.

Methods

N1 immortalized and primary prostate fibroblasts and lung fibroblasts (the later included as positive controls) were grown in serum free defined media supplemented with vehicle, TGFbeta, IL-4, and IL-13 alone or in combination with or without IL-4 or IL-13 inhibitors. Cells were evaluated by immunofluorescence for alphaSMA and collagen expression in situ, by immunoblot for IL-4Ralpha and IL-13R1alpha expression, by WST assay for cell proliferation, by ELISA for protein expression, or by Sircol assay for collagen production.

Results

Prostate and lung fibroblasts expressed the IL-4Ralpha and IL-13R1alpha receptor proteins. N1 and primary prostate and lung fibroblasts underwent myofibroblast phenoconversion and significantly up-regulated collagen 1 and αSMA protein expression in response to IL-4 or IL-13 treatment. These effects were ablated through co-treatment with IL-4 and IL-13 receptors antibodies. Low concentrations of IL-4 and IL-13 significantly up-regulated N1 and primary prostate cell proliferation. Prostate fibroblasts treated with IL-4 or IL-13 significantly and almost equivalently up-regulated IL-13 protein expression, suggesting the establishment of an autocrine IL-13 expression loop. Treatment with IL-4 alone up-regulated IL-4, but not IL-13, protein expression. Neither IL-4 nor IL-13 affected TGFbeta expression levels.

Conclusions

The results of these studies show that IL-4 and IL-13 promote myofibroblast phenoconversion and collagen accumulation, and thus support a role for IL-4/IL-13 promotion of prostatic fibrosis associated with LUTD. A major new discovery reported here is that Th2 cytokines, particularly IL-13, can establish autocrine expression loops in prostate fibroblasts that may promote continual myofibroblast phenoconversion in the lower urinary tract. These findings support the investigation of small molecules or antibodies that target Th2 IL-4/IL13 activities for the prevention or treatment of lower urinary tract fibrosis.

Funding

Supported by NIH/NIDDK grant 1P20DK090870?03 (JAM) and 1U54DK104310 (JAM).