Macrophages lacking scavenger receptor A show a decrease in binding and uptake of acetylated low-density lipoprotein and of apoptotic thymocytes, but not of oxidatively damaged red blood cells.
Macrophages lacking scavenger receptor A show a decrease in binding and uptake of acetylated low-density lipoprotein and of apoptotic thymocytes, but not of oxidatively damaged red blood cells.
复制标题
缺乏清道夫受体A的巨噬细胞表现出乙酰化低密度脂蛋白和凋亡胸腺细胞的结合和摄取减少，但氧化损伤的红细胞则没有减少。
DOI：
10.1073/pnas.94.15.8127
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发表时间：
1997
影响因子：
11.1
通讯作者：
Steinberg,D
中科院分区：
文献类型：
--
作者：
Terpstra,V;Kondratenko,N;Steinberg,D
巨噬细胞与氧化损伤的红细胞(OxRBC)和凋亡的胸腺细胞的结合在许多情况下与磷脂双层不对称性的丧失有关，即质膜外叶上磷脂酰丝氨酸的表达增加。氧化修饰的低密度脂蛋白(OxLDL)可以竞争这些配体与巨噬细胞的结合。然而，负责的受体(S)仍有待确定。目前的研究表明，小鼠腹膜巨噬细胞完全缺乏清道夫受体A(SRA)与OxRBC的结合，与野生型巨噬细胞一样有效，但其对乙酰低密度脂蛋白的结合和摄取减少了80%以上。凋亡胸腺细胞的结合和氧化低密度脂蛋白的结合也减少了，但仅减少了20%-30%。我们的结论是，SRA不参与识别富含磷脂酰丝氨酸的膜，但有助于OxLDL与凋亡的胸腺细胞的结合。OxRBC的结合几乎完全依赖于钙离子，而与凋亡胸腺细胞的结合不完全依赖，这表明在这两种条件下，巨噬细胞摄取OxRBC的机制是不同的。
Macrophage binding of oxidatively damaged red blood cells (OxRBC) and apoptotic thymocytes correlates in many instances with a loss of phospholipid bilayer asymmetry, i.e., with an increase in expression of phosphatidylserine on the outer leaflet of the plasma membrane. Oxidatively modified LDL (OxLDL) can compete for the binding of these ligands to macrophages. However, the receptor(s) responsible remains to be identified. The present studies show that mouse peritoneal macrophages totally lacking scavenger receptor A (SRA) bound OxRBC just as effectively as wild-type macrophages, whereas their binding and uptake of acetyl LDL was reduced by more than 80%. Binding of apoptotic thymocytes and binding of OxLDL were also reduced, but only by 20–30%. We conclude that SRA is not involved in the recognition of phosphatidylserine-rich membranes but contributes to the binding of OxLDL and apoptotic thymocytes. The binding of OxRBC was almost totally calcium-dependent, whereas the binding of apoptotic thymocytes was not, suggesting that the mechanisms involved in their uptake by macrophages under these conditions were different.