Rapamycin Inhibits the Growth and Collagen Production of Fibroblasts Derived from Human Urethral Scar Tissue.

Delai Fu,Hecheng Li,Tie Chong,Shanlong Huang,Jian Yin,Zhaolun Li

doi:10.1155/2018/7851327

Abstract

Rapamycin can inhibit fibroblast proliferation, collagen accumulation, and urethral stricture in rabbits. Transforming growth factor-beta-1 (TGF-β1) signaling, with downstream recruitment of Smad2, is known to promote fibrosis. This in vitro study examined the effects of rapamycin on fibroblasts derived from human urethral scar tissue (FHUS) and investigated the possible mechanism with respect to regulation of TGF-β1 signaling. FHUS were cultured from urethral scar tissues collected from four patients with urethral stricture. The cells were exposed to different concentrations of rapamycin (0, 10, 20, 40, 80, or 160 ng/ml) for 24 or 48 hours. Cell growth was assessed by the MTT assay. Collagen content was measured based on hydroxyproline levels. The mRNA expressions of Smad2, eIF-4E, and alpha-1 chains of collagen types I and III (Col1α1 and Col3α1) were determined by semiquantitative reverse-transcription PCR. The protein expressions of Smad2, phospho-Smad2, and eIF-4E were evaluated by western blot. Rapamycin caused a concentration-dependent inhibition of FHUS growth at 24 and 48 hours (P < 0.01). Rapamycin decreased total collagen content (P < 0.01), collagen content per 105 cells (P < 0.05), and mRNA expressions of Col1α1 and Col3α1 (P < 0.05) in a concentration-dependent manner. Rapamycin elicited concentration-dependent reductions in the mRNA (P < 0.05) and protein (P < 0.01) expressions of Smad2 and eIF-4E. The two highest concentrations of rapamycin also enhanced phospho-Smad2 levels (P < 0.01). In conclusion, the present study confirmed that rapamycin may reduce the growth and collagen production of FHUS, possibly through inhibition of TGF-β1 signaling.

Highlights

Urethral stricture is a common problem in men, with a reported prevalence of 229–627 per 100,000 males [1]
Since activation of Smad2 is established as a downstream effector of the TGF-β1 signaling pathway and since eukaryotic translation initiation factor 4E (eIF-4E) is a translational coactivator of TGF-β signaling [15], our data are consistent with the possibility that rapamycin reduces from human urethral scar tissue (FHUS) growth and collagen production, associated with inhibition of TGF-β1 signaling
Tamaki et al [19] found that rapamycin could regulate the deposition of COL-I in the extracellular matrix through inhibition of COL-I synthesis and promotion of COL-I degradation. Consistent with this previous investigation, our results indicated that rapamycin evoked concentration-dependent reductions in total collagen production and mRNA expressions of Col1α1 and Col3α1 by FHUS

Summary

Introduction

Urethral stricture is a common problem in men, with a reported prevalence of 229–627 per 100,000 males [1]. The etiology of urethral stricture is iatrogenic or idiopathic in around two-thirds of cases, with less common causes including trauma, infection, and chronic inflammation [3, 4]. Surgery is the main treatment method for urethral stricture [5, 6]. The surgical techniques used vary widely from dilation to endoscopic internal urethrotomy and urethroplasty, depending on the length and location of the stricture and the experience of the surgeon [5,6,7,8]. Multiple complications can occur even when the most appropriate surgical technique is used, with disease recurrence being the most common complication [9]. The management of urethral stricture remains a surgical challenge

Objectives

Methods

Discussion

Conclusion