Asumendi A, Alvarez A, Martinez I, Smedsrød B, Vidal-Vanaclocha F
Department of Cellular Biology and Morphological Sciences, School of Medicine and Dentistry, University of the Basque Country, Leioa, Spain.
Hepatology. 1996 Jun;23(6):1521-9. doi: 10.1053/jhep.1996.v23.pm0008675173.
Using fluorescein isothiocyanate-conjugated ovalbumin (OVA-FITC), 125I-mannan, or 125I-invertase as specific ligands for the mannose receptor, we have quantified its activity in mouse and rat hepatic sinusoidal endothelium (HSE), under both basal conditions and after lipopolysaccharide (LPS) or human recombinant interleukin-1beta (IL-1beta) stimulations. Mouse treatment for 4 hours with 5 microg/kg IL-1beta significantly increased OVA-FITC uptake by HSE. Ligand uptake exhibited a sublobular compartmentalization: In control mice as well as in IL-1beta-stimulated mice, the ligand distributed preferentially in the periportal and septal areas; no OVA-FITC was observed in the perivenous sinusoids. In vitro exposure of mouse HSE to 100 pg/mL LPS or 1 ng/mL IL-1beta for 6 hours significantly (P < .01) increased OVA-FITC uptake. Blocking IL-1 receptors in HSE by addition of 100 ng/mL IL-1 receptor antagonist (IL-1Ra) before stimulation with LPS or IL-1beta abrogated the increase in mannose receptor-mediated uptake. In vitro endocytosis assays showed that rat HSE uptake of 125I-mannan or 125I-invertase progressively increased with both exposure time and concentration of added IL-1beta. Upregulation of mannose receptor-mediated uptake in response to IL-1beta or LPS was also blocked by previous addition of IL-1Ra to rat HSE. Flow cytometric analysis showed a significant HSE heterogeneity in mannose receptor-mediated endocytosis in response to IL-1beta treatment: type I endothelial cells (EC-I, defined by their small size and high cytoplasmic density) significantly (P < .01) increased OVA-FITC uptake compared with type II endothelial cells (EC-II, defined by their large size and low cytoplasmic density). In addition, the subset of EC-I contained three times more IL-1beta-binding cells than the EC-II subset. Because EC-I and EC-II are preferentially located in the periportal and perivenous segments of hepatic sinusoids, respectively, these results suggest that IL-1beta, apart from upregulating mannose receptor activity, contributes to the sublobular compartmentalization of this endothelial cell function.
使用异硫氰酸荧光素偶联的卵清蛋白（OVA-FITC）、125I-甘露聚糖或125I-转化酶作为甘露糖受体的特异性配体，我们在基础条件下以及脂多糖（LPS）或重组人白细胞介素-1β（IL-1β）刺激后，对小鼠和大鼠肝窦内皮细胞（HSE）中的甘露糖受体活性进行了定量。用5μg/kg IL-1β处理小鼠4小时可显著增加HSE对OVA-FITC的摄取。配体摄取呈现小叶下分区：在对照小鼠以及IL-1β刺激的小鼠中，配体优先分布在门静脉周围和间隔区域；在肝静脉窦中未观察到OVA-FITC。将小鼠HSE体外暴露于100 pg/mL LPS或1 ng/mL IL-1β 6小时可显著（P <.01）增加OVA-FITC摄取。在用LPS或IL-1β刺激前添加100 ng/mL白细胞介素-1受体拮抗剂（IL-1Ra）阻断HSE中的IL-1受体，可消除甘露糖受体介导的摄取增加。体外内吞试验表明，大鼠HSE对125I-甘露聚糖或125I-转化酶的摄取随暴露时间和添加的IL-1β浓度的增加而逐渐增加。预先向大鼠HSE中添加IL-1Ra也可阻断IL-1β或LPS诱导的甘露糖受体介导的摄取上调。流式细胞术分析显示，在对IL-1β处理的反应中，HSE在甘露糖受体介导的内吞作用方面存在显著异质性：I型内皮细胞（EC-I，其特点是体积小且细胞质密度高）与II型内皮细胞（EC-II，其特点是体积大且细胞质密度低）相比，OVA-FITC摄取显著（P <.01）增加。此外，EC-I亚群中IL-1β结合细胞的数量是EC-II亚群的三倍。由于EC-I和EC-II分别优先位于肝窦的门静脉周围和肝静脉周围段，这些结果表明，IL-1β除了上调甘露糖受体活性外，还导致了这种内皮细胞功能在小叶下的分区。
