Puente Navazo M D, Daviet L, Ninio E, McGregor J L
INSERM Unit 331, Faculté de Medicine René Laënnec, Lyon, France.
Arterioscler Thromb Vasc Biol. 1996 Aug;16(8):1033-9. doi: 10.1161/01.atv.16.8.1033.
Uptake of oxidized LDL (oxLDL) by macrophages is one of the key events implicated in the initiation and perpetuation of atherosclerotic lesions. One of the major scavenging receptors, which binds modified LDL, on macrophages is CD36. The domain on CD36 implicated in the binding of oxLDL remains to be elucidated. In this study, COS cells transfected with human CD36 cDNA bound FITC-oxidized human LDL in a dose-dependent, saturable manner. This binding was inhibited by an excess of oxLDL but not by native LDL. Anti-CD36 monoclonal antibodies (mAbs) 10/5, FA6-152, and 8A6 (directed against domain 155-183), but not mAb 13/10 (directed against domain 30-76), completely inhibited oxLDL binding to human CD36-transfected COS cells. Cells transfected with a chimeric human CD36 construct (hmh 155-183), resulting from the swapping of human domain 155-183 with its murine counterpart, resulted in low binding of oxLDL. In contrast, cells transfected with a chimeric murine CD36 construct (mhm 155-183), resulting from the swapping of murine domain 155-183 with its human counterpart, resulted in high binding of oxidized human LDL. Binding of oxLDL to cells transfected by chimeric construct mhm 155-183 were only partially blocked by mAbs 10/5, FA6-152, and 8A6. In the present study we have identified, for the first time, an important functional domain (encompassing amino acids 155-183) on CD36 involved in the binding of oxLDL. In addition, the binding site for oxidized human LDL on murine CD36 seems to differ from its human counterpart.
巨噬细胞摄取氧化型低密度脂蛋白（oxLDL）是动脉粥样硬化病变起始和持续过程中的关键事件之一。巨噬细胞上与修饰型低密度脂蛋白结合的主要清道夫受体之一是CD36。CD36上与oxLDL结合相关的结构域仍有待阐明。在本研究中，转染了人CD36 cDNA的COS细胞以剂量依赖性、可饱和的方式结合异硫氰酸荧光素（FITC）氧化的人低密度脂蛋白。这种结合被过量的oxLDL抑制，但不被天然低密度脂蛋白抑制。抗CD36单克隆抗体（mAb）10/5、FA6 - 152和8A6（针对结构域155 - 183），而非mAb 13/10（针对结构域30 - 76），完全抑制oxLDL与人CD36转染的COS细胞的结合。用嵌合人CD36构建体（hmh 155 - 183）转染的细胞，该构建体是通过将人结构域155 - 183与其鼠对应结构域交换得到的，导致oxLDL的结合较低。相反，用嵌合鼠CD36构建体（mhm 155 - 183）转染的细胞，该构建体是通过将鼠结构域155 - 183与人对应结构域交换得到的，导致氧化型人低密度脂蛋白的高结合。嵌合构建体mhm 155 - 183转染的细胞与oxLDL的结合仅被mAb 10/5、FA6 - 152和8A6部分阻断。在本研究中，我们首次鉴定出CD36上一个参与oxLDL结合的重要功能结构域（包含氨基酸155 - 183）。此外，氧化型人低密度脂蛋白在鼠CD36上的结合位点似乎与其人对应物不同。
