CD163, A MARKER OF PERIVASCULAR MACROPHAGES IS UPREGULATED ON MICROGLIA IN SIVE

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 大胶质细胞和小胶质细胞是感染HIV的人类和感染SIV的猕猴的中枢神经系统中感染的主要细胞类型。小胶质细胞是大脑的常驻巨噬细胞，并且已经显示出对中枢神经系统（CNS）稳态的甚至微小的干扰都相当敏感，并且容易被激活。小胶质细胞的活化诱导细胞形态和细胞表面受体表达的变化。CD 163是清道夫受体家族的成员，具有富含半胱氨酸的结构域（SCRC），被鉴定为触珠蛋白-血红蛋白（Hp-Hb）复合物的受体，并且仅由单核细胞-巨噬细胞谱系的细胞表达。我们通过多种技术在体外和体内检测了有或没有SIVE的动物在SIV感染后不同时间的CD 163表达。 我们的数据显示，在正常和急性SIV感染的动物或无脑炎的晚期AIDS动物中，CD 163由单核细胞/巨噬细胞谱系的细胞表达，包括血管周围巨噬细胞，但不包括实质小胶质细胞。 CD 163的表达被检测到在慢性感染的猕猴SIVE病变周围的激活的小胶质细胞（HLA-DR+）与严重脑炎的结合珠蛋白-血红蛋白复合物（Hp-Hb）的组织中的存在下，表明血脑屏障的破坏。通过用Hp-Hb复合物刺激，还在体外诱导了小胶质细胞中的CD 163表达，这表明需要Hp-Hb复合物的相互作用来触发CD 163的上调。 为了证实小胶质细胞的活化与CD 163 RNA的存在和上调相关，我们用Hp-Hb处理从恒河猴脑分离的小胶质细胞0、6、12、18和48小时，并进行定量实时PCR。我们观察到在接触后18小时内，用触珠蛋白-血红蛋白处理的小胶质细胞中CD 163 RNA增加了2.5倍。 我们的结论是，CD 163是一个选择性标记血管周围的巨噬细胞在正常猕猴和SIV感染的早期阶段。 然而，在感染后期，CD 163也标记可能由于血管损害而被激活的小胶质细胞。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Macrophages and microglia are the major cell types infected in the central nervous system of humans infected with HIV and macaques infected with SIV. Microglia are the resident macrophages of the brain and have been shown to be quite sensitive to even minor disturbances of central nervous system (CNS) homeostasis, and are readily activated. Activation of microglia induces changes in cellular morphology and in the expression of cell surface receptors. CD163 is a member of the scavenger receptor family with cysteine-rich domains (SCRC) identified as a receptor of haptoglobin-hemoglobin (Hp-Hb) complex and exclusively expressed by cells of monocyte-macrophage lineage. We examined the expression of CD163 in vitro and in vivo by multiple techniques and at varying times after SIV infection in animals with or without SIVE. Our data show that CD163 is expressed by cells of monocyte/macrophage lineage including perivascular macrophages but not parenchymal microglia in normal and acutely SIV-infected animals or animals with terminal AIDS without encephalitis. CD163 expression was detected in activated microglia (HLA-DR+) surrounding SIVE lesions in chronically infected macaques with severe encephalitis in the presence of haptoglobin-haemoglobin complex (Hp-Hb) in the tissue suggesting breakdown of the blood-brain-barrier. CD163 expression was also induced in microglia in vitro by stimulation with Hp-Hb complex indicating that the interaction of the Hp-Hb complex is required to trigger the upregulation of CD163. To confirm that activation of microglia was associated with the presence and upregulation of CD163 RNA we treated microglia isolated from rhesus macaque brain with Hp-Hb for 0, 6, 12, 18 and 48 h and performed quantitative real-time PCR. We observed a 2.5 fold increase of CD163 RNA in the microglia treated with haptoglobin-hemoglobin within 18hrs of exposure. We conclude that CD163 is a selective marker of perivascular macrophages in normal macaques and during the early phases of SIV infection. However, latter in infection CD163 also labels microglia that have been activated probably as a result of vascular compromise.