The changes in glycosylation after partial hepatectomy enhance collagen binding of vitronectin in plasma

Abstract

Vitronectin is a multifunctional glycoprotein present in the extracellular matrix and plasma. Changes in rat vitronectin were studied during liver regeneration after partial hepatectomy. Carbohydrate concentrations of vitronectin decreased to 2/3 of sham-operated rats at 24 h after partial hepatectomy. Carbohydrate composition and lectin reactivity indicated that N-glycosylation and sialylation of vitronectin changed markedly after partial hepatectomy, while amino acid composition did not change significantly. We previously showed that deN-glycosylation of vitronectin in vitro affects collagen binding among various ligands (Yoneda et al., Biochemistry (1998) 37, 6351-6360). Vitronectins from partially hepatectomized rats at 24 h were found to exhibit markedly enhanced binding to type I collagen. The effect of sialylation on collagen binding was further examined using enzymatically deglycosylated vitronectin of nonoperated rats. Collagen binding increased by 1.2 times after deN-glycosylation of vitronectin, while it increased more than 2.9 times after desialylation. Various glycosyltransferases in liver are known to change after partial hepatectomy, including the attenuation of N-oligosaccharide transferase. The findings therefore suggest that the collagen binding of vitronectin is modulated by the alteration of peptide glycosylation caused by postoperative physiological changes of glycosyltransferases and that the change may contribute to tissue remodeling processes.

Glycosylation in a Mammalian Expression System Is Critical for the Production of Functionally Active Leukocyte Immunoglobulin-like Receptor A3 Protein

“…This is similar to previous data showing that glycosylation significantly alters the pI of other similar glycoproteins (20,21). Moreover, glycosylation can provide conformational and structural stability (22,23) and may facilitate correct folding (23,24) and importantly modulate ligand binding and functions (20,25,26). We found that rLILRA3 in its non-glycosylated form required extensive refolding steps, was highly susceptible to aggregation/oxidation, and was non-functional despite being of high purity and high yield (up to 15 mg/liter).…”

Survival Signals of Hepatic Stellate Cells in Liver Regeneration Are Regulated by Glycosylation Changes in Rat Vitronectin, Especially Decreased Sialylation

“…Further study demonstrated that multimerization of rat VN increases during liver regeneration after partial hepatectomy and that increases in the collagen-binding activity are synchronized with the glycan changes in vivo (15). The molecular mass of VN purified from partially hepatectomized (PH-VN) rats at 24 h had shrunk to 65 kDa compared with the 68 -69 kDa of VNs from sham-operated (SH) and non-operated (NO) rats.…”

Matrix Restructuring During Liver Regeneration is Regulated by Glycosylation of the Matrix Glycoprotein Vitronectin

“…2B, the purified vitronectins bound to type I collagen by ELISA in a concentration-dependent manner, and PH-VN was found to exhibit much greater binding to collagen, about 3 times higher than that of SH-VN and NO-VN (Uchibori-Iwaki, H., et al 2000). The enhanced binding of PH-VN to immobilized collagen shown by ELISA was supported by surface plasmon resonance (SPR), as shown in Fig.…”

“…1977) of PH-VN was 0.040 when taking that of SH-VN as 0.0. All three vitronectins had the same N-terminal sequence, indicating that the three vitronectins had high homology among the primary sequence (Uchibori-Iwaki, H., et al 2000).…”

“…Vitronectin was purified from plasma at different times during the liver regeneration process and analyzed by SDS-PAGE (Uchibori-Iwaki, H., et al 2000). As shown in Fig.…”