Aberrant Transforming Growth Factor‐β Activation Recruits Mesenchymal Stem Cells During Prostatic Hyperplasia

: Benign prostatic hyperplasia (BPH) is the overgrowth of prostate tissues with high prevalence in older men. BPH pathogenesis is not completely understood, but it is believed to be a result of de novo overgrowth of prostatic stroma. In this study, we show that aberrant activation of transforming growth factor-β (TGF-β) mobilizes mesenchymal/stromal stem cells (MSCs) in circulating blood, which are recruited for the prostatic stromal hyperplasia. Elevated levels of active TGF-β were observed in both a phenylephrine-induced prostatic hyperplasia mouse model and human BPH tissues. Nestin lineage tracing revealed that 39.6% ± 6.3% of fibroblasts and 73.3% ± 4.2% smooth muscle cells were derived from nestin+ cells in Nestin-Cre, Rosa26-YFPflox/+mice. Nestin+ MSCs were increased in the prostatic hyperplasia mice. Our parabiosis experiment demonstrate that nestin+ MSCs were mobilized and recruited to the prostatic stroma of wild-type mice and gave rise to the fibroblasts. Moreover, injection of a TGF-β neutralizing antibody (1D11) inhibits mobilization of MSCs, their recruitment to the prostatic stroma and hyperplasia. Importantly, knockout of TβRII in nestin+ cell lineage ameliorated stromal hyperplasia. Thus, elevated levels of TGF-β-induced mobilization and recruitment of MSCs to the reactive stroma resulting in overgrowth of prostate tissues in BPH and, thus, inhibition of TGF-β activity could be a potential therapy for BPH. SIGNIFICANCE Activation of transforming growth factor-β (TGF-β) plays a role in the pathogenesis of benign prostatic hyperplasia. TGF-β activation results in recruitment of MSCs and their subsequent differentiation into prostatic stromal cells. Thus, careful modulation of TGF-β activity could provide potential therapeutic options in the management of benign prostatic hyperplasia.