Endogenous carbohydrate-binding proteins of rabbit and human bladder.
OBJECTIVE
To identify the endogenous lectins of the human bladder with the long-term goal of developing improved strategies for the treatment of interstitial cystitis and other bladder disorders.


METHODS
Rabbit and human bladder sections were examined histochemically using biotinylated neoglycoconjugates. Affinity chromatography of extracts of rabbit bladder was performed on immobilized lactose to purify the galactose-binding protein.


RESULTS
Biotinylated beta-D-galactose neoglycoconjugate showed the strongest specific staining of the rabbit and human bladder sections. The beta-D-N-acetylglucosamine neoglycoconjugate also showed significant staining; the alpha-L-fucose, alpha-D-mannose, alpha-D-N-acetylneuraminic acid, and alpha-D-N-acetylgalactosamine neoglycoconjugates showed either very weak or no reaction. The strong Ca2+ -independent binding of beta-D-galactose neoglycoconjugates suggested the presence of galectins in rabbit and human bladder. Affinity chromatography of rabbit bladder extract on lactose gel yielded a galectin of about 30 kDa, consistent with the molecular biological data confirming the expression of galectin-3 in bladder.


CONCLUSIONS
Beta-D-galactose binds strongly and specifically to rabbit and human bladder tissue sections. This information would be useful for the purpose of modifying drugs used for the treatment of bladder disorders with ligands of galactose-binding lectins to improve their retention in the bladder.
Puch
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Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, USA.
Bhavanandan
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VP
D000818:Animals; D050260:Carbohydrate Metabolism; D006801:Humans; D037102:Lectins / Q000032:analysis*; D011817:Rabbits; D001743:Urinary Bladder / Q000737:chemistry*; D019459:Urothelium / Q000737:chemistry
D037102:Lectins