Survival Signals of Hepatic Stellate Cells in Liver Regeneration Are Regulated by Glycosylation Changes in Rat Vitronectin, Especially Decreased Sialylation
Survival Signals of Hepatic Stellate Cells in Liver Regeneration Are Regulated by Glycosylation Changes in Rat Vitronectin, Especially Decreased Sialylation
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DOI：
10.1074/jbc.m109.077016
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发表时间：
2010-06-04
影响因子：
4.8
通讯作者：
Ogawa, Haruko
中科院分区：
文献类型：
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作者：
Sano, Kotone;Miyamoto, Yasunori;Ogawa, Haruko
细胞外基质（ECM）分子在许多生物和病理过程中起着重要作用。在组织重塑过程中，糖基化的ECM分子与正常组织的分子不同，这是由于许多负责聚糖合成的蛋白质表达的变化。玻璃体连接蛋白（VN）是识别肝星状细胞（hsc）上整合素的主要ECM分子。本研究试图阐明VN聚糖的变化如何调节造血干细胞的存活，造血干细胞在肝脏再生中起着关键作用。从部分肝切除（PH）和假手术（SH）大鼠和未手术（NO）大鼠的24 h血浆中纯化VN。大鼠造血干细胞（rHSCs）在PH-VN中的黏附，以及局灶黏附激酶的磷酸化，减少到no或SH-VN的一半。去氮化的NO-VN使造血干细胞的扩散减少到对照VN的一半，这表明VN唾液化对造血干细胞的激活很重要。液相色谱/多级质谱分析每个VN的gluc糖肽确定位点特异性糖基化。除了主要的双天线络合物型n -聚糖外，杂交型n -聚糖在Asn（167）上特异存在。发现在Thr(110)-Thr（124）区域存在高度唾液化的o -聚糖。PH-VN中，二醇型o -聚糖和络合型n -聚糖减少，核心聚焦型n -聚糖增加。此外，二维PAGE后的免疫检测表明，每个VN中都存在高和低唾液化分子，并显示PH-VN中的高唾液化明显减弱。本研究提出VN糖基化的改变可调节底物与大鼠造血干细胞的粘附，从而导致基质重组。
The extracellular matrix (ECM) molecules play important roles in many biological and pathological processes. During tissue remodeling, the ECM molecules that are glycosylated are different from those of normal tissue owing to changes in the expression of many proteins that are responsible for glycan synthesis. Vitronectin (VN) is a major ECM molecule that recognizes integrin on hepatic stellate cells (HSCs). The present study attempted to elucidate how changes in VN glycans modulate the survival of HSCs, which play a critical role in liver regeneration. Plasma VN was purified from partially hepatectomized (PH) and sham-operated (SH) rats at 24 h after operation and non-operated (NO) rats. Adhesion of rat HSCs (rHSCs), together with phosphorylation of focal adhesion kinase, in PH-VN was decreased to one-half of that in NO-or SH-VN. Spreading of rHSCs on desialylated NO-VN was decreased to one-half of that of control VN, indicating the importance of sialylation of VN for activation of HSCs. Liquid chromatography/multiple-stage mass spectrometry analysis of Glu-C glycopeptides of each VN determined the site-specific glycosylation. In addition to the major biantennary complex-type N-glycans, hybrid-type N-glycans were site-specifically present at Asn(167). Highly sialylated O-glycans were found to be present in the Thr(110)-Thr(124) region. In PH-VN, the disialyl O-glycans and complex-type N-glycans were decreased while core-fucosylated N-glycans were increased. In addition, immunodetection after two-dimensional PAGE indicated the presence of hyper- and hyposialylated molecules in each VN and showed that hypersialylation was markedly attenuated in PH-VN. This study proposes that the alteration of VN glycosylation modulates the substrate adhesion to rat HSCs, which is responsible for matrix restructuring.