Immunocytochemical localization of MG1 mucin in human bulbourethral glands

Abstract

Salivary mucins MG1 and MG2 have been found in the oral cavity where they perform several functions such as the formation of the mucous layer covering the oral mucosa and teeth. Recent studies have demonstrated their presence in other organs and tissues. The aim of this study was to determine their expression in human bulbourethral (Cowper's) glands. Normal bulbourethral glands were obtained at surgery and fixed in a mixture of 1% paraformaldehyde-1.25% glutaraldehyde in 0.1 M cacodylate buffer and embedded in Epon resin. Thin sections were labeled with rabbit antibodies to MG1 or to an N-terminal synthetic peptide of MG2, followed by gold-labeled goat anti-rabbit IgG. The granules of all mucous cells were intensely reactive with anti-MG1, whereas no labeling was detected for MG2. These results indicate that MG1 is not exclusively a salivary component and furthermore show that bulbourethral glands represent a significant source of the MG1 detected in human seminal plasma.

Tissue Distribution of Murine Muc19/Smgc Gene Products

“…We find comparable results in mice, except for expression of Muc5b transcripts in epididymis. The recent results of Piludu et al (2009) suggest that MUC5B glycoproteins are probably contributed by bulbourethral glands, a tissue not tested by Russo et al (2006). Piludu et al (2009) localized anti-MG1 reactivity to bulbourethral mucous cells.…”

Differences in the seminal plasma proteome are associated with oxidative stress levels in men with normal semen parameters

“…Mucins are highly glycosylated proteins involved with mucosal innate immune response (53,54). Specifically, mucin-5B is a high-molecular-weight, gel-forming protein (55). Russo et al (56) were the first to demonstrate the presence of mucin-5B in the seminal plasma.…”

“…Russo et al (56) were the first to demonstrate the presence of mucin-5B in the seminal plasma. Thereafter, Piludu et al (55) demonstrated that this protein is secreted by the bulbourethral glands, where it seems to protect the epithelium against infection. The function of mucin-5B in semen remains unknown, but it is suggested that it might modulate sperm transport in the male and female reproductive tracts (55,57).…”

“…Thereafter, Piludu et al (55) demonstrated that this protein is secreted by the bulbourethral glands, where it seems to protect the epithelium against infection. The function of mucin-5B in semen remains unknown, but it is suggested that it might modulate sperm transport in the male and female reproductive tracts (55,57). In lungs, oxidative stress promotes an up-regulation of mucin-5B in the respiratory epithelium, both in vivo and in vitro (58).…”

Multi-omics biomarker pipeline reveals elevated levels of protein-glutamine gamma-glutamyltransferase 4 in seminal plasma of prostate cancer patients

“…Since analysis of prostate cancer-specific molecules in urine, such as PCA3, often requires normalization to KLK3 mRNA to account for the sample dilution 13 , we also investigated if normalization of protein concentrations by total KLK3 protein in SP would improve the performance of markers ( Figure 5). Levels of MUC5B, a mucin exclusively expressed and secreted by the Cowper's glands 50 , were significantly lower in PCa (0.4-fold change, P =0.005) before, but not after normalization by KLK3. Due to its exclusive expression in the Cowper's glands and its potentially high variability in SP, MUC5B thus was not considered as a candidate.…”