Richards Maureen H, Narasipura Srinivas D, Kim Stephanie, Seaton Melanie S, Lutgen Victoria, Al-Harthi Lena
Department of Immunology and Microbiology, Rush University Medical Center, Chicago, Illinois.
Glia. 2015 Mar;63(3):441-51. doi: 10.1002/glia.22763. Epub 2014 Oct 21.
HIV-mediated neuropathogenesis is a multifaceted process involving several players, including resident brain cells (neurons, astrocytes, and microglia) and infiltrating cells [peripheral blood mononuclear cells (PBMCs)]. We evaluated the dynamic interaction between astrocytes and infiltrating PBMCs as it impacts HIV in the CNS. We demonstrate that human primary-derived astrocytes (PDAs) predominantly secrete Wnt 1, 2b, 3, 5b, and 10b. Wnts are small secreted glycoproteins that initiate either β-catenin-dependent or independent signal transduction. The Wnt pathway plays a vital role in the regulation of CNS activities including neurogenesis, neurotransmitter release, synaptic plasticity, and memory consolidation. We show that HIV infection of PDAs altered astrocyte Wnt profile by elevating Wnts 2b and 10b. Astrocyte conditioned media (ACM) inhibited HIV replication in PBMCs by 50%. Removal of Wnts from ACM abrogated its ability to suppress HIV replication in PBMCs. Inversely, PBMCs supernatant activated PDAs, as demonstrated by a 10-fold increase in HLA-DR and a 5-fold increase in IFNγ expression, and enhanced astrocyte susceptibility to HIV by 2-fold, which was mediated by IFNγ in a Stat-3-dependent manner. Collectively, these data demonstrate a dynamic interaction between astrocytes and PBMCs, whereby astrocyte-secreted Wnts exert an anti-HIV effect on infected PBMCs and PBMCs, in turn, secrete IFNγ that enhance astrocyte susceptibility to productive HIV infection and mediate their activation.
HIV介导的神经病变是一个多方面的过程,涉及多个参与者,包括脑内驻留细胞(神经元、星形胶质细胞和小胶质细胞)以及浸润细胞[外周血单核细胞(PBMC)]。我们评估了星形胶质细胞与浸润性PBMC之间的动态相互作用,因为它会影响中枢神经系统中的HIV。我们证明,人原代星形胶质细胞(PDA)主要分泌Wnt 1、2b、3、5b和10b。Wnt是小的分泌型糖蛋白,可启动β-连环蛋白依赖性或非依赖性信号转导。Wnt信号通路在中枢神经系统活动的调节中起着至关重要的作用,包括神经发生、神经递质释放、突触可塑性和记忆巩固。我们表明,PDA感染HIV通过升高Wnt 2b和10b改变了星形胶质细胞的Wnt谱。星形胶质细胞条件培养基(ACM)可将PBMC中的HIV复制抑制50%。从ACM中去除Wnt消除了其抑制PBMC中HIV复制的能力。相反,PBMC上清液激活了PDA,HLA-DR增加了10倍,IFNγ表达增加了5倍,同时使星形胶质细胞对HIV的易感性增加了2倍,这是由IFNγ以Stat-3依赖性方式介导的。总的来说,这些数据证明了星形胶质细胞与PBMC之间的动态相互作用,即星形胶质细胞分泌的Wnt对受感染的PBMC发挥抗HIV作用,而PBMC反过来分泌IFNγ,增强星形胶质细胞对HIV有效感染的易感性并介导其激活。