Minten Carsten, Alt Carsten, Gentner Melanie, Frei Elisabeth, Deutsch Urban, Lyck Ruth, Schaeren-Wiemers Nicole, Rot Antal, Engelhardt Britta
1 Theodor Kocher Institute, University of Bern, CH-3012 Bern, Switzerland.
Brain. 2014 May;137(Pt 5):1454-69. doi: 10.1093/brain/awu045. Epub 2014 Mar 12.
The Duffy antigen/receptor for chemokines, DARC, belongs to the family of atypical heptahelical chemokine receptors that do not couple to G proteins and therefore fail to transmit conventional intracellular signals. Here we show that during experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis, the expression of DARC is upregulated at the blood-brain barrier. These findings are corroborated by the presence of a significantly increased number of subcortical white matter microvessels staining positive for DARC in human multiple sclerosis brains as compared to control tissue. Using an in vitro blood-brain barrier model we demonstrated that endothelial DARC mediates the abluminal to luminal transport of inflammatory chemokines across the blood-brain barrier. An involvement of DARC in experimental autoimmune encephalomyelitis pathogenesis was confirmed by the observed ameliorated experimental autoimmune encephalomyelitis in Darc(-/-) C57BL/6 and SJL mice, as compared to wild-type control littermates. Experimental autoimmune encephalomyelitis studies in bone marrow chimeric Darc(-/-) and wild-type mice revealed that increased plasma levels of inflammatory chemokines in experimental autoimmune encephalomyelitis depended on the presence of erythrocyte DARC. However, fully developed experimental autoimmune encephalomyelitis required the expression of endothelial DARC. Taken together, our data show a role for erythrocyte DARC as a chemokine reservoir and that endothelial DARC contributes to the pathogenesis of experimental autoimmune encephalomyelitis by shuttling chemokines across the blood-brain barrier.
达菲抗原/趋化因子受体(DARC)属于非典型七螺旋趋化因子受体家族,该家族受体不与G蛋白偶联,因此无法传递传统的细胞内信号。在此我们表明,在实验性自身免疫性脑脊髓炎(一种多发性硬化症的动物模型)中,血脑屏障处DARC的表达上调。与对照组织相比,人类多发性硬化症脑内皮质下白质微血管中DARC染色呈阳性的数量显著增加,这证实了上述发现。使用体外血脑屏障模型,我们证明内皮细胞DARC介导炎症趋化因子从管腔外到管腔内穿过血脑屏障的转运。与野生型对照同窝小鼠相比,在Darc(-/-) C57BL/6和SJL小鼠中观察到实验性自身免疫性脑脊髓炎病情改善,这证实了DARC参与实验性自身免疫性脑脊髓炎的发病机制。对骨髓嵌合的Darc(-/-)和野生型小鼠进行的实验性自身免疫性脑脊髓炎研究表明,实验性自身免疫性脑脊髓炎中炎症趋化因子血浆水平的升高依赖于红细胞DARC的存在。然而,完全发展的实验性自身免疫性脑脊髓炎需要内皮细胞DARC的表达。综上所述,我们的数据表明红细胞DARC作为趋化因子储存库发挥作用,并且内皮细胞DARC通过在血脑屏障间穿梭趋化因子而促成实验性自身免疫性脑脊髓炎的发病机制。