Light and Electron Microscopic Immunohistochemical Localization of Protein Gene Product 9.5 and Ubiquitin Immunoreactivities in the Human Epididymis and Vas Deferens1

Abstract

The distribution of protein gene product 9.5 (PGP) and ubiquitin immunoreactivities in the ductuli efferentes, ductus epididymidis, and ductus deferens of humans was studied by Western blot analyses and light and electron microscopic immunocytochemistry. PGP immunoreactivity was intense in the ductuli efferentes and weak in the ductus epididymidis and ductus deferens, while ubiquitin immunoreactivity was intense in the ductuli efferentes and ductus epididymidis and very weak in the ductus deferens. In the ductuli efferentes epithelium, PGP immunolabeling was observed in the cytoplasm of principal cells, whereas ubiquitin immunoreactivity was found in the nucleus and cytoplasm of principal cells and ciliated cells. In the ductus epididymidis epithelium, only scattered cells (mitochondria-rich cells) showed PGP immunoreaction in their cytoplasm, whereas ubiquitin immunostaining was detected in the nucleus and cytoplasm of most epithelial cells, except for the cauda, where ubiquitin immunolabeling was observed only in the nuclei. The ductus deferens showed no immunostaining for PGP, and only nuclear immunoreactivity to ubiquitin. The ultrastructural localization of PGP immunoreactivity was in the apical cytosol and microvilli. In addition to these locations, ubiquitin immunoreactivity was also found in the nucleus of all cell types and cilia of ciliated cells. Although the distribution of PGP and ubiquitin immunoreactivities in humans differs from that reported in rats, it seems that PGP and ubiquitinated proteins are secreted into the epididymal lumen in both species.

The Region-Specific Functions of Two Ubiquitin C-Terminal Hydrolase Isozymes along the Epididymis

“…2). We detected a high level of UCH-L1 in the caput epididymis, the main maturation organ, whereas the UCH-L3 level was high in the cauda epididymis, the main storage organ [10]. These region-specific variations in UCH-L1 and UCH-L3 level suggest that they have different functions in the epididymis.…”

“…During epididymal passage, ubiquitination may trigger apoptotic mechanisms that recognize and eliminate abnormal sper- matozoa, and ubiquitination is believed to play an important role in controlling sperm quality to ensure the production of intact, functional spermatozoa [10,27,37]. Ubiquitination of abnormal spermatozoa predominantly occurs in the caput epididymis [37].…”

“…Numerous proteins, secreted in an apocrine manner by the epididymal epithelium, are implicated in spermatozoa maturation [18]. Two major components of the ubiquitin-dependent proteolytic pathway, ubiquitin and UCH-L1 (PGP9.5), are expressed in epididymal tissue [10,35]. Ubiquitin is present in human seminal plasma [26], and defective spermatozoa become ubiquitinated during epididymal passage [23,37].…”

Innervation and Immunohistochemical Characteristics of Epididymis in Alpaca Camelid (Vicugna Pacos)

“…These cells are slender cells without an apparent connection with the epithelial basal lamina and are similar to mithocondria-rich cells. These cells were reported in the initial epididymal segments in men (Fraile et al, 1996) and in other mammalian species (Martìnez-Garcìa et al, 1995). In the alpaca, they were observed to contain lectins and were postulated to regulate epididymal ionic composition and intraluminal pH (Parillo et al, 2009b).…”

The New Function of Two Ubiquitin C-Terminal Hydrolase Isozymes as Reciprocal Modulators of Germ Cell Apoptosis

“…Ubiquitin is present in defective spermatozoa (Fig. 5), and proteins in these cells become ubiquitinated during epididymal passage [8,23,33]. Ubiquitination in the epididymis may trigger apoptotic mechanisms that recognize and eliminate abnormal spermatozoa [31].…”