Sonic hedgehog regulates prostatic growth and epithelial differentiation

Area of Science:

• Developmental Biology
• Molecular Signaling
• Urology

Background:

• The Sonic hedgehog (SHH) signaling pathway plays a vital role in epithelial-mesenchymal interactions during tissue development and disease.
• Its specific role in ventral prostate (VP) development in rats has not been fully elucidated.

Purpose of the Study:

• To investigate the role of the SHH signaling pathway in rat ventral prostate (VP) development.
• To determine if SHH signaling is critical for prostatic induction and subsequent growth, branching, and differentiation.

Main Methods:

• Studied Shh and Ptc gene expression in relation to prostate development.
• Utilized in vitro organ culture of mouse and rat urogenital sinus (UGS) explants.
• Manipulated SHH signaling using cyclopamine and recombinant SHH in cultured rat VP explants.
• Examined effects of SHH inhibition on prostatic duct morphology and epithelial proliferation and differentiation using immunohistochemistry (p63, cytokeratin 14).

Main Results:

• SHH signaling is not critical for initial prostatic induction but is essential for later stages of VP development.
• Disruption of SHH signaling reduced VP organ size, increased ductal tip number, and decreased epithelial proliferation.
• SHH inhibition in the presence of testosterone accelerated ductal canalization and led to aberrant epithelial differentiation, resembling cribriform prostatic intraepithelial neoplasia (PIN).

Conclusions:

• SHH signaling is indispensable for prostate growth, branching morphogenesis, and maintaining normal epithelial proliferation.
• Androgen-stimulated prostate growth without SHH signaling results in precocious and aberrant epithelial differentiation, potentially contributing to neoplastic changes like PIN.