Abstract
Background Prostate-specific membrane antigen (PSMA), also known as glutamate carboxypeptidase II (GCPII), is an important diagnostic and therapeutic target in prostate cancer. PSMA/GCPII is also expressed in many healthy tissues, but its function has only been established in the brain and small intestine.
Several research groups have attempted to produce PSMA/GCPII-deficient mice to study the physiological role of PSMA/GCPII in detail. The outcomes of these studies differ dramatically, ranging from embryonic lethality to production of viable PSMA/GCPII-deficient mice without any obvious phenotype.
Methods We produced PSMA/GCPII-deficient mice (hereafter also referred as Folh1(-/-) mice) by TALEN-mediated mutagenesis on a C57BL/6NCrl background. Using Western blot and an enzyme activity assay, we confirmed the absence of PSMA/GCPII in our Folh1(-/-) mice.
We performed anatomical and histopathological examination of selected tissues with a focus on urogenital system. We also examined the PSMA/GCPII expression profile within the mouse urogenital system using an enzyme activity assay and confirmed the presence of PSMA/GCPII in selected tissues by immunohistochemistry.
Results Our Folh1(-/-) mice are viable, breed normally, and do not show any obvious phenotype. Nevertheless, aged Folh1(-/-) mice of 69-72 weeks exhibit seminal vesicle dilation, which is caused by accumulation of luminal fluid.
This phenotype was also observed in Folh1(+/-) mice; the overall difference between our three cohorts (Folh1(-/-), Folh1(+/-), and Folh1(+/+)) was highly significant (P < 0.002). Of all studied tissues of the mouse urogenital system, only the epididymis appeared to have a physiologically relevant level of PSMA/GCPII expression.
Additional experiments demonstrated that PSMA/GCPII is also present in the human epididymis. Conclusions In this study, we provide the first evidence characterizing the reproductive tissue phenotype of PSMA/GCPII-deficient mice.
These findings will help lay the groundwork for future studies to reveal PSMA/GCPII function in human reproduction.