Li Feng, Pascal Laura E, Wang Ke, Zhou Yibin, Balasubramani Goundappa K, O'Malley Katherine J, Dhir Rajiv, He Kai, Stolz Donna, DeFranco Donald B, Yoshimura Naoki, Nelson Joel B, Chong Tie, Guo Peng, He Dalin, Wang Zhou
Department of Urology, The First Affiliated Hospital of Xi'an Jiaotong University Xi'an, Shaanxi, China.
Department of Urology, The Second Affiliated Hospital of Xi'an Jiaotong University Xi'an, Shaanxi, China.
Am J Clin Exp Urol. 2020 Feb 25;8(1):9-17. eCollection 2020.
Our recent studies identifying the presence of luminal secretory protein PSA in the stroma, decreased E-cadherin expression, and reduced number of tight junction kiss points in benign prostatic hyperplasia (BPH) tissues suggest that epithelial barrier permeability is increased in BPH. However, the cause of increased epithelial permeability in BPH is unclear. Transforming growth factor beta 1 (TGF-β1) has been reported to be up-regulated in clinical BPH specimens and TGF-β1 overexpression induced fibrosis and inflammation in a murine model. TGF-β1 was reported to repress the expression of E-cadherin in benign prostatic cells. However, whether and how TGF-β1 up-regulation affects epithelial barrier permeability is unknown. Here, benign prostatic epithelial cell lines BHPrE1 and BPH-1 were utilized to determine the impact of TGF-β1 treatment on epithelial barrier, tight junctions, and expression of E-cadherin and claudin 1 by transepithelial electrical resistance (TEER) measurement, FITC-dextran trans-well diffusion assays, qPCR, as well as transmission electron microscopy (TEM) observation. Laser capture micro-dissection (LCM) combined with reverse transcription-polymerase chain reaction (qPCR) were utilized to determine the expression of E-cadherin and claudin 1 in BPH patient specimens. TGF-β1 treatment decreased TEER, increased FITC-dextran diffusion, and reduced the mRNA expression of junction protein claudin 1 in cultured cell monolayers. Claudin 1 mRNA but not E-cadherin mRNA was down-regulated in the luminal epithelial cells in BPH nodules compared to normal prostate tissues. Our studies suggest that TGF-β1 could increase the permeability through decreasing the expression of claudin 1 and inhibiting the formation of tight junctions in BHPrE1 and BPH-1 monolayers. These results suggest that TGF-β1 might play an important role in BPH pathogenesis through increasing the permeability of luminal epithelial barrier in the prostate.
我们最近的研究发现，在良性前列腺增生（BPH）组织的基质中存在腔内分泌蛋白PSA，E-钙黏蛋白表达降低，紧密连接吻点数量减少，这表明BPH中上皮屏障通透性增加。然而，BPH中上皮通透性增加的原因尚不清楚。据报道，转化生长因子β1（TGF-β1）在临床BPH标本中上调，并且TGF-β1过表达在小鼠模型中诱导纤维化和炎症。据报道，TGF-β1可抑制良性前列腺细胞中E-钙黏蛋白的表达。然而，TGF-β1上调是否以及如何影响上皮屏障通透性尚不清楚。在这里，利用良性前列腺上皮细胞系BHPrE1和BPH-1，通过跨上皮电阻（TEER）测量、FITC-葡聚糖跨孔扩散试验、qPCR以及透射电子显微镜（TEM）观察，来确定TGF-β1处理对上皮屏障、紧密连接以及E-钙黏蛋白和闭合蛋白1表达的影响。利用激光捕获显微切割（LCM）结合逆转录-聚合酶链反应（qPCR）来确定BPH患者标本中E-钙黏蛋白和闭合蛋白1的表达。TGF-β1处理降低了TEER，增加了FITC-葡聚糖扩散，并降低了培养的细胞单层中连接蛋白闭合蛋白1的mRNA表达。与正常前列腺组织相比，BPH结节的腔内上皮细胞中闭合蛋白1 mRNA而非E-钙黏蛋白mRNA下调。我们的研究表明，TGF-β1可通过降低闭合蛋白1的表达并抑制BHPrE1和BPH-1单层中紧密连接的形成来增加通透性。这些结果表明，TGF-β1可能通过增加前列腺腔内上皮屏障的通透性在BPH发病机制中起重要作用。
