Effects of lipoprotein lipase on uptake and transcytosis of low density lipoprotein (LDL) and LDL-associated α-tocopherol in a porcine in vitro blood-brain barrier model
Effects of lipoprotein lipase on uptake and transcytosis of low density lipoprotein (LDL) and LDL-associated α-tocopherol in a porcine in vitro blood-brain barrier model
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DOI：
10.1074/jbc.m203989200
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发表时间：
2002-08-09
影响因子：
4.8
通讯作者：
Sattler, W
中科院分区：
文献类型：
--
作者：
Goti, D;Balazs, Z;Sattler, W
在本研究中，脂蛋白脂肪酶（LPL）的贡献，低密度脂蛋白（LDL）的全息颗粒和LDL-脂质（α-生育酚（alphaTocH））的营业额在原代猪脑毛细血管内皮细胞（BCECs）进行了研究。增加LPL浓度的BCEC导致高达11倍的高LDL holoparticle细胞协会。LPL有助于LDL holoparticle营业额，这是一种响应LDL受体上调而大幅增加的效应。添加LPL可使BCEC中LDL相关alphaTocH的选择性摄取增加高达5倍。LPL依赖性选择性alphaTocH摄取不受脂肪酶抑制剂tetrahydrolipstatin的影响，但在蛋白聚糖硫酸化被NaClO 3处理抑制的细胞中受到实质性抑制。因此，LDL相关alphaTocH的选择性摄取需要LPL与硫酸乙酰肝素蛋白聚糖的相互作用。尽管BCEC中清道夫受体BI（SR-BI）的高水平腺病毒过表达导致选择性LDL-alphaTocH摄取增加2倍，但SR-BI不与LPL以协同方式起作用。尽管向BCEC Transwell培养物中添加LPL显著增加了LDL全颗粒细胞结合和LDL相关alphaTocH的选择性摄取，但该猪血脑屏障（BBB）模型中的全颗粒转胞吞作用不受LPL存在的影响。在转胞吞作用实验期间的重要观察结果是LDL颗粒的大量alphaTocH消耗，所述LDL颗粒被重新分泌到基底外侧隔室中。在LPL缺陷小鼠中证实了LPL依赖性alphaTocH跨BBB摄取的相关性。不存在LPL导致脑α TocH浓度显著低于对照动物中观察到的浓度。
During the present study the contribution of lipoprotein lipase (LPL) to low density lipoprotein (LDL) holoparticle and LDL-lipid (alpha-tocopherol (alphaTocH)) turnover in primary porcine brain capillary endothelial cells (BCECs) was investigated. The addition of increasing LPL concentrations to BCECs resulted in up to 11-fold higher LDL holoparticle cell association. LPL contributed to LDL holoparticle turnover, an effect that was substantially increased in response to LDL-receptor upregulation. The addition of LPL increased selective uptake of LDL-associated alphaTocH in BCECs up to 5-fold. LPL-dependent selective alphaTocH uptake was unaffected by the lipase inhibitor tetrahydrolipstatin but was substantially inhibited in cells where proteoglycan sulfation was inhibited by treatment with NaClO3. Thus, selective uptake of LDL-associated alphaTocH requires interaction of LPL with heparan-sulfate proteoglycans. Although high level adenoviral overexpression of scavenger receptor BI (SR-BI) in BCECs resulted in a 2-fold increase of selective LDL-alphaTocH uptake, SR-BI did not act in a cooperative manner with LPL. Although the addition of LPL to BCEC Transwell cultures significantly increased LDL holoparticle cell association and selective uptake of LDL-associated alphaTocH, holoparticle transcytosis across this porcine blood-brain barrier (BBB) model was unaffected by the presence of LPL. An important observation during transcytosis experiments was a substantial alphaTocH depletion of LDL particles that were resecreted into the basolateral compartment. The relevance of LPL-dependent alphaTocH uptake across the BBB was confirmed in LPL-deficient mice. The absence of LPL resulted in significantly lower cerebral alphaTocH concentrations than observed in control animals.