Department of Emergency and Organ Transplantation (DETO), University of Bari Aldo Moro, Bari, Italy.
Department of Emergency and Organ Transplantation (DETO), University of Bari Aldo Moro, Bari, Italy.
Ann Anat. 2022 Oct;244:151988. doi: 10.1016/j.aanat.2022.151988. Epub 2022 Aug 17.
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.
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).
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-B), 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.
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.
尿路上皮是覆盖在膀胱内表面的多层上皮，作为血液-尿液屏障，参与维持整个机体的健康。糖蛋白参与细胞的成熟和分化，因此在多层上皮的形态和功能中起着关键作用。本研究旨在通过凝集素组织化学检查马的尿路上皮尿路上皮的糖蛋白模式。
该研究涉及来自 4 匹种马的膀胱组织。组织切片用一组 11 种凝集素进行染色，结合皂化和唾液酸酶消化（Ks）。
基底细胞显示高甘露糖 N-糖（Con A）、α2,6-连接的唾液酸（SNA）和与 Galβ1,3GalNAc（T 抗原）（KsPNA）和末端 N-乙酰半乳糖胺（Tn 抗原）（KsSBA）连接的 O-连接的唾液酸化糖蛋白。年轻的中间细胞表达末端 N-乙酰葡萄糖胺（GlcNAc）（GSA II）、半乳糖（GSA I-B）、T-和 Tn 抗原（PNA、SBA）。成熟的中间细胞显示额外的高甘露糖 N-糖、O-连接的唾液酸化糖蛋白（唾液酸化 T 抗原、唾液酸化 Tn 抗原）、α2,6-和 α2,3-连接的唾液酸（MAL II）、α1,2-连接的岩藻糖（UEA I）和 GlcNAc（KsWGA）。后者残基标志着与上覆表面层的边界。很少有 Con A 阳性的中间细胞被观察到穿过整个尿路上皮的厚度。表面细胞显示出额外的糖蛋白，如与 GalNAc 结合的 DBA 结合的 T 抗原和唾液酸（KsDBA）。很少有表面细胞含有α1,3-连接的岩藻糖（LTA），而其他一些细胞显示出粘液型糖蛋白的腔内分泌，其末端为 GalNAcα1,3(LFucα1,2)Galβ1,3/4GlcNAcβ1（DBA）。尿路上皮的腔面表达了最复杂的糖蛋白模式，因为在所示的糖蛋白中缺乏仅α1,3-连接的岩藻糖。
本研究表明，糖蛋白模式从尿路上皮的基底到表面层变得更加复杂，并且表面细胞可以通过糖蛋白的分泌来改变尿液的成分。
