Scavenger receptor B1, the HDL receptor, is expressed abundantly in liver sinusoidal endothelial cells.
Scavenger receptor B1, the HDL receptor, is expressed abundantly in liver sinusoidal endothelial cells.
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DOI：
10.1038/srep20646
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发表时间：
2016-02-11
影响因子：
4.6
通讯作者：
Anderson CL
中科院分区：
文献类型：
--
作者：
Ganesan LP;Mates JM;Cheplowitz AM;Avila CL;Zimmerer JM;Yao Z;Maiseyeu A;Rajaram MV;Robinson JM;Anderson CL
来自外周组织的胆固醇由HDL携带，在被HDL受体SR-B1摄取后在肝脏中代谢。肝细胞长期以来一直被认为是唯一表达SR-B1的肝细胞，然而，在这项研究中，我们描述了两个不同的免疫荧光（IF）实验表明，否则。使用高分辨率共聚焦显微镜，采用小鼠肝脏的120 nm切片，提高z轴分辨率，我们鉴定了肝窦内皮细胞（LSEC），用FcγRIIb标记，作为肝脏内表达丰富SR-B1的细胞。相比之下，用β-连环蛋白鉴定的肝细胞表达的水平相当弱，尽管SR-B1的光学分辨率不足。因此，我们采用了不同的IF策略，首先通过梯度离心将解离的肝细胞分离成两部分，肝细胞（实质细胞）和LSEC（非实质细胞）。通过流式细胞术表征SR-B1的细胞表达的两个部分，我们发现LSEC表达相当数量的SR-B1，而在肝细胞中SR-B1表达几乎不可察觉。通过真实的时间PCR评估SR-B1的mRNA，我们发现LSEC中的信使表达比肝细胞中高约5倍。
Cholesterol from peripheral tissue, carried by HDL, is metabolized in the liver after uptake by the HDL receptor, SR-B1. Hepatocytes have long been considered the only liver cells expressing SR-B1; however, in this study we describe two disparate immunofluorescence (IF) experiments that suggest otherwise. Using high-resolution confocal microscopy employing ultrathin (120 nm) sections of mouse liver, improving z-axis resolution, we identified the liver sinusoidal endothelial cells (LSEC), marked by FcγRIIb, as the cell within the liver expressing abundant SR-B1. In contrast, the hepatocyte, identified with β-catenin, expressed considerably weaker levels, although optical resolution of SR-B1 was inadequate. Thus, we moved to a different IF strategy, first separating dissociated liver cells by gradient centrifugation into two portions, hepatocytes (parenchymal cells) and LSEC (non-parenchymal cells). Characterizing both portions for the cellular expression of SR-B1 by flow cytometry, we found that LSEC expressed considerable amounts of SR-B1 while in hepatocytes SR-B1 expression was barely perceptible. Assessing mRNA of SR-B1 by real time PCR we found messenger expression in LSEC to be about 5 times higher than in hepatocytes.