Analysis of androgen- and TGF-beta-regulated proteins in Sertoli cells

• Applicant: Privatdozent Dr. Lutz Konrad
• Subject Area: Reproductive Medicine, Urology
• Term: from 2008 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 34016037

The human androgen receptor (AR) is a transcription factor responsible for Sertoli cell (SC) function and spermatogenesis. In contrast, elevated TGF-beta levels disturb the blood-testisbarrier and cause apoptosis of germ cells. In a previous study, AR-GAG repeat length in testis DNA/mRNA of patients with normal spermatogenesis (NSP) or spermatogenic impairment was found to be within the physiological range and not correlating to severe histological impairment, AR expression, and testosterone or LH levels, suggesting other factors to be responsible for disturbed spermatogenesis. Additionally, we generated two rat Sertoli cell lines transfected with the human AR containing an either short (18) or long (36) CAG repeat. Stimulated with different concentrations of testosterone we found a moderate downregulation of clusterin orTGF-betas, not correlating with CAG repeat length. In contrast, TGF-betas increased the secretion of clusterin. In the present study, the following aims will be addressed: 1) to generate SC lines with CAG repeats >40 known to be pathological; 2) to evaluate testosterone and AR-CAG-dependent gene expression pattern using microarray analysis; 3) to test, whether these genes are involved in an induction of meiosis or germ cell differentiation in vitro; 4) to test, whether these genes are relevant in patients showing normal or hypospermatogenesis and different CAG repeat lengths; 5) to evaluate effects of testosterone alone or in combination with TGFbetas on extracellular and nuclear clusterin; 6) to analyse the association of clusterin (extracellular and nuclear) with Impaired spermatogenesis. Data will provide new information on androgen-regulated genes in SCs and their relevance for spermatogenesis.

• DFG Programme: Clinical Research Units
• Subproject of: KFO 181: Male Factor Infertility due to Impaired Spermatogenesis