Cell- and region-specific expression of sugar chains in the mouse epididymal epithelium using lectin histochemistry combined with immunohistochemistry

Differential expression of glycans in the urothelial layers of horse urinary bladder

BACKGROUND

Urothelium is a multilayer epithelium covering the inner surface of the urinary bladder that acts as a blood-urine barrier and is involved in maintaining the wellbeing of the whole organism. Glycans serve in the maturation and differentiation of cells and thus play a key role in the morphology and function of the multilayered epithelium. The aim of the present study was to examine the glycoprotein pattern of the horse urinary bladder urothelium by lectin histochemistry.

METHODS

The study involved urinary bladders from four horse stallions. Tissue sections were stained with a panel of eleven lectins, in combination with saponification and sialidase digestion (Ks).

RESULTS

Basal cells displayed high-mannose N-glycans (Con A), α2,6-linked sialic acid (SNA), and O-linked sialoglycans with sialic acids linked to Galβl,3GalNAc (T antigen) (KsPNA) and terminal N-acetylgalactosamine (Tn antigen) (KsSBA). The young intermediate cells expressed terminal N-acetylglucosamine (GlcNAc) (GSA II), galactose (GSA I-B₄), T- and Tn antigens (PNA, SBA). The mature intermediate cells showed additional high-mannose N-glycans, O-linked sialoglycans (sialyl-T antigen, sialyl-Tn antigen), α2,6- and α2,3-linked sialic acid (MAL II), α1,2-linked fucose (UEA I), and GlcNAc (KsWGA). The latter residue marked the boundary with the overlying surface layer. Few Con A positive intermediate cells were seen to cross the entire urothelium thickness. The surface cells showed additional glycans such as T antigen and sialic acids linked to GalNAc binding DBA (KsDBA). Few surface cells contained α1,3-linked fucose (LTA), whereas some other cells displayed intraluminal secretion of mucin-type glycans terminating with GalNAcα1,3(LFucα1,2)Galβ1,3/4GlcNAcβ1 (DBA). The luminal surface expressed the most complex glycan pattern in the urothelium because only α1,3-linked fucose lacked among the demonstrated glycans.

CONCLUSIONS

This study showed that the glycan pattern becomes more complex from the basal to surface layer of the urothelium and that surface cells could modify the composition of urine via the secretion of glycoproteins.

Postnatal cadmium administration affects the presence and distribution of carbohydrates in the sperm membrane during maturation in the epididymis in adult Wistar rats

Cadmium (Cd) is a heavy metal related to a decrease in sperm parameters. The transit of spermatozoa through the epididymis is necessary to generate changes in the sperm membrane, such as the assembly of various carbohydrates that are added to the spermatazoan's surface to prepare it for successful fertilisation of the oocyte. No studies have yet analysed whether Cd alters the presence and distribution of these carbohydrates. We aimed to evaluate the changes induced by Cd in the distribution pattern of N-acetylglucosamine, sialic acid, mannose and fucose on the sperm membrane in the epididymis (e.g. caput, corpus, cauda) and if it alters the epididymal epithelium. Male Wistar pups were treated with Cd doses (0.125, 0.25 and 0.5mg/kg) on postnatal days 1-49. At postnatal day 90, they were humanely killed, sperm samples were obtained from the epididymis and tissue samples were taken for histological analysis. Cd concentrations in the blood and epididymis increased in proportion to the dose administered and decreased the serum testosterone levels and sperm quality. Histological analysis revealed alterations in the epithelium in all Cd-treated groups. Cd altered the distribution patterns of carbohydrates and fluorescence indices. All these alterations affected the structure and functioning of sperm.

Histochemical evaluation of postnatal lectin-binding sites in the mouse prostate

The prostate is a male accessory genital gland that plays an essential role in reproductive function. To understand the cytological characteristics of differentiating prostatic cells, we used lectin histochemistry combined with immunohistochemistry to examine the distribution of lectin-binding sites on prostatic cells during postnatal development in the mouse. During postnatal development, Hippeastrum Hybrid Lectin (HHL) lectin reacted consistently with the luminal cells of all prostatic lobes (regions), whereas the Ricinus Communis Agglutinin I (RCA-I) and Soybean Agglutinin (SBA) lectins showed remarkable differences with age, region, and cell type. We found that the lectin-binding pattern in differentiating prostatic cells acquired adult characteristics around 3 weeks after birth. The results indicate that prostatic cell differentiation during postnatal development in mice is characterized by the presence of cell- and region-specific lectin-binding sites in the prostate, suggesting that there may also be cellular and regional differences in their function. Furthermore, some lectins (HHL, RCA-I, and SBA) could provide useful markers for research into cell differentiation and for the pathological evaluation of prostatic diseases or in the diagnosis of male infertility.

Lectin-binding sites in epithelial cells of the mouse prostate gland

The prostate is an exocrine gland in the male reproductive tract that secretes seminal fluids. To gain insight into the cytochemical properties of prostatic epithelial cells, the characteristics of glycoconjugates in mouse prostate sections were examined by lectin histochemistry and immunohistochemistry. Characteristic staining patterns were observed, depending on the type of lectins present in the epithelia. Luminal cells reacted specifically with mannose-binding lectins (Galanthus nivalis lectin, Hippeastrum hybrid lectin, Narcissus pseudonarcissus lectin) and Maclura pomifera lectin in all lobes of the prostate. Luminal cells also expressed galactose, N-acetyl-D-galactosamine (GalNAc), N-acetyl-D-glucosamine (GlcNAc), and fucose residues in the lateral and ventral lobes. Basal cells expressed GlcNAc and fucose, and reacted with Datura stramonium lectin and Aleuria aurantia lectin in all lobes. These results indicate that in the mouse prostate, the selectivity of lectin-binding sites for distinct cell types and lobe-dependent staining may relate to cellular and regional differences in function. Furthermore, some lectins selectively bound to prostatic epithelial cells, indicating their potential use as markers for the histopathological evaluation of prostatic diseases, cancer diagnosis, or male infertility.

Cytokeratin localization and basal cell differentiation in the epididymal epithelium during postnatal development of the mouse

The epididymis is a male genital organ that has plays various functions, including sperm concentration, maturation, and storage. The epididymal epithelium consists of principal cells, clear cells, and basal cells. To comprehensively understand the occurrence and morphological differentiation of basal cells, we examined the expression and localization of cytokeratins (CKs) in the epididymal epithelium during postnatal development of the mouse. Immunohistochemical staining showed that, in adult mice, CK5 and CK14 were exclusively expressed in the cytoplasm of basal cells. During postnatal development, basal cells that stained positive for CK5 and CK14 first appeared in immature columnar epithelial cells in mice aged 1 week. The immunoreactivity became progressively stronger in mice aged 2-3 weeks. In mice aged 3 weeks, the immunoreactivity was strong in regions IV and V. In mice aged ≥ 4 weeks, strong immunoreactivity was observed in all epididymal regions. CK5 and CK14 could be useful markers of differentiation in epididymal basal cells. These basal cells originate from immature columnar epithelial cells and are of two types—dome-shaped and flask-shaped—. The flask-shaped cells are mainly located in the initial segment of the mouse epididymis.