Nio Junko, Takahashi-Iwanaga Hiromi, Morimatsu Masami, Kon Yasuhiro, Iwanaga Toshihiko
Laboratory of Anatomy, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18-Nishi 9, 060-0818, Kita-ku, Sapporo, Japan.
Histochem Cell Biol. 2006 Jul;126(1):45-56. doi: 10.1007/s00418-005-0142-5. Epub 2006 Jan 11.
Galectin is an animal lectin that has high affinity to beta-galactoside of glycoconjugates. In the present study, cellular expression of galectin subtypes in the urinary system of adult mice was examined by in situ hybridization and immunohistochemistry. The major subtype expressed in the murine urinary system was galectin-3, which was expressed continuously from the kidney to the distal end of the urethra. The renal cortex expressed galectin-3 more intensely than the medulla. Renal galectin-3 immunoreactivity was strongest in the cortical collecting ducts, where principal cells were the sole cellular source. All cell layers of the transitional epithelium from the renal pelvis to the urethra strongly expressed galectin-3 at the mRNA and protein levels. An electron microscopic study demonstrated diffuse cytoplasmic localization of galectin-3 in principal cells of the collecting ducts and in the bladder epithelial cells. Urethral galectin-3 expression at the pars spongiosa decreased in intensity near the external urethral orifice, where the predominant subtype of galectin was substituted by galectin-7. The muscular layer of the ureter and urinary bladder contained significant signals for galectin-1. Taken together, the observations indicate that the adult urinary system shows intense and selective expression of galectin-3 in epithelia of the uretic bud- and cloaca-derivatives.
半乳糖凝集素是一种对糖缀合物的β-半乳糖苷具有高亲和力的动物凝集素。在本研究中，通过原位杂交和免疫组织化学检测了成年小鼠泌尿系统中半乳糖凝集素亚型的细胞表达。在小鼠泌尿系统中表达的主要亚型是半乳糖凝集素-3，其从肾脏到尿道远端持续表达。肾皮质比髓质更强烈地表达半乳糖凝集素-3。肾半乳糖凝集素-3免疫反应性在皮质集合管中最强，其中主细胞是唯一细胞来源。从肾盂到尿道的移行上皮的所有细胞层在mRNA和蛋白质水平上都强烈表达半乳糖凝集素-3。电子显微镜研究表明半乳糖凝集素-3在集合管主细胞和膀胱上皮细胞中呈弥漫性细胞质定位。尿道海绵体部的半乳糖凝集素-3表达在尿道外口附近强度降低，在那里半乳糖凝集素的主要亚型被半乳糖凝集素-7取代。输尿管和膀胱的肌肉层含有半乳糖凝集素-1的显著信号。综上所述，这些观察结果表明成年泌尿系统在输尿管芽和泄殖腔衍生物的上皮中显示出半乳糖凝集素-3的强烈且选择性表达。
