Expression of protocadherin 11Yb (PCDH11Yb) in seminal germ cells is correlated with fertility status in men.

Protocadherin 11 Y-linked (PCDH11Y), a member of the cadherin superfamily, is predominantly expressed in the central nervous system, is encoded by the Yp11.2 locus and exists in three isoforms: 11Ya, 11Yb and 11Yc. PCDH11Y is upregulated by retinoic acid signalling and is essential for spermatogonial differentiation and initiation of meiosis. PCDH11Y mediates Wnt signalling, which plays a crucial role in the differentiation of various cell types. PCDH11Y has been implicated in neuronal cell differentiation and proliferation, but its association with spermatogenesis has not yet been addressed. Hence, in order to address the possible role of PCDH11Y in relation to spermatogenesis, the expression analysis of PCDH11Y in the seminal germ cells of fertile and infertile males were carried out employing RT-PCR, western blotting and immunofluorescence analysis. In the present study, PCDH11Yb, but not PCDH11Ya or PCDH11Yc, was expressed in germ cells isolated from the semen of all 13 men with proven fertility. However, in several subjects from various infertility classes, there was complete absence or a significant reduction in the expression of PCDH11Yb. PCDH11Y exhibited prominent localisation on the head and midpiece region of spermatozoa from fertile men, whereas spermatozoa from infertile subjects had either weak or abnormal localisation patterns for PCDH11Y. In addition, downregulation of canonical Wnt signalling was correlated with defective expression of PCDH11Y in spermatozoa of infertile men, as evidenced by downregulation of the Wnt targets C-Myc and C-Jun. In conclusion, expression levels of PCDH11Yb in germ cells in the semen were correlated with the fertility status of men.