Galectin-1, an endogenous lectin produced by arterial cells, binds lipoprotein(a) [Lp(a)] in situ: relevance to atherogenesis.
Lipoprotein(a) [Lp(a)], a modified LDL molecule, is implicated in atherogenesis. Mechanisms of the accumulation of [Lp(a)] in atherosclerotic vessels is lacking in literature. We sought to investigate the complementarities of the carbohydrate structures on Lp(a) and LDL with galectin-1(a carbohydrate binding protein) and whether endogenous galectin-1 binds Lp(a) in situ. We investigated T-antigen structures on Lp(a) and LDL by enzyme-linked lectin assay using T-antigen specific lectins, galectin-1 and jacalin. Both jacalin and galectin-1 bound strongly to Lp(a) and to a much lesser extent, to LDL. Galectin-1 recognition of the lipoproteins was abolished when the O-linked sugars were selectively removed. Localization of endogenous galectin-1 within histological sections of human internal mammary artery and in vitro binding of Lp(a) to the tissues was analyzed by immunohistochemical staining. The Lp(a)-binding pattern was found to overlap with the localization of galectin-1. The poor Lp(a)-binding on inhibiting tissue galectin-1 with lactose, suggested the binding of Lp(a) to galectin-1. This may be suggestive of a mechanism by which Lp(a) accumulates within arterial walls in atherogenesis.
Chellan
Bijoy
B
Department of Biochemistry, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, 695011, India.
Narayani
Jayakumari
J
Appukuttan
Padinjaradath S
PS
D000957:Antigens, Viral, Tumor / Q000737:chemistry / Q000378:metabolism; D050197:Atherosclerosis; D037483:Galectin 1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D017270:Lipoprotein(a) / Q000378:metabolism*; D008077:Lipoproteins, LDL / Q000378:metabolism; D008323:Mammary Arteries / Q000166:cytology* / Q000378:metabolism; D037121:Plant Lectins / Q000378:metabolism; D011485:Protein Binding
D000957:Antigens, Viral, Tumor; D037483:Galectin 1; C445499:LGALS1 protein, human; D017270:Lipoprotein(a); D008077:Lipoproteins, LDL; D037121:Plant Lectins; C043696:jacalin