Qin Aiping, Lai De-Hua, Liu Qifa, Huang Weijun, Wu Ya-Ping, Chen Xiaoyong, Yan Sunxing, Xia Huimin, Hide Geoff, Lun Zhao-Rong, Ayala Francisco J, Xiang Andy Peng
Department of Hematology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
Center for Stem Cell Biology and Tissue Engineering, The Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China.
Proc Natl Acad Sci U S A. 2017 Feb 7;114(6):1365-1370. doi: 10.1073/pnas.1619665114. Epub 2017 Jan 25.
Mesenchymal stromal cells (MSCs) have recently been shown to play important roles in mammalian host defenses against intracellular pathogens, but the molecular mechanism still needs to be clarified. We confirmed that human MSCs (hMSCs) prestimulated with IFN-γ showed a significant and dose-dependent ability to inhibit the growth of two types of Toxoplasma gondii [type I RH strain with green fluorescent proteins (RH/GFP) or type II PLK strain with red fluorescent proteins (PLK/RED)]. However, in contrast to previous reports, the anti-T. gondii activity of hMSCs was not mediated by indoleamine 2,3-dioxygenase (IDO). Genome-wide RNA sequencing (RNA-seq) analysis revealed that IFN-γ increased the expression of the p65 family of human guanylate-binding proteins (hGBPs) in hMSCs, especially hGBP1. To analyze the functional role of hGBPs, stable knockdowns of hGBP1, -2, and -5 in hMSCs were established using a lentiviral transfection system. hGBP1 knockdown in hMSCs resulted in a significant loss of the anti-T. gondii host defense property, compared with hMSCs infected with nontargeted control sequences. hGBP2 and -5 knockdowns had no effect. Moreover, the hGBP1 accumulation on the parasitophorous vacuole (PV) membranes of IFN-γ-stimulated hMSCs might protect against T. gondii infection. Taken together, our results suggest that hGBP1 plays a pivotal role in anti-T. gondii protection of hMSCs and may shed new light on clarifying the mechanism of host defense properties of hMSCs.
间充质基质细胞（MSCs）最近被证明在哺乳动物宿主抵御细胞内病原体的过程中发挥重要作用，但其分子机制仍有待阐明。我们证实，用干扰素-γ预刺激的人MSCs（hMSCs）表现出显著且剂量依赖性的能力，可抑制两种类型的刚地弓形虫的生长[带有绿色荧光蛋白的I型RH株（RH/GFP）或带有红色荧光蛋白的II型PLK株（PLK/RED）]。然而，与先前的报道相反，hMSCs的抗弓形虫活性并非由吲哚胺2,3-双加氧酶（IDO）介导。全基因组RNA测序（RNA-seq）分析显示，干扰素-γ可增加hMSCs中人鸟苷酸结合蛋白（hGBPs）p65家族的表达，尤其是hGBP1。为了分析hGBPs的功能作用，使用慢病毒转染系统在hMSCs中稳定敲低hGBP1、-2和-5。与感染非靶向对照序列的hMSCs相比，hMSCs中hGBP1的敲低导致抗弓形虫宿主防御特性显著丧失。hGBP2和-5的敲低没有效果。此外，hGBP1在干扰素-γ刺激的hMSCs的寄生泡（PV）膜上的积累可能有助于抵御弓形虫感染。综上所述，我们的结果表明，hGBP1在hMSCs抗弓形虫保护中起关键作用，可能为阐明hMSCs宿主防御特性的机制提供新的线索。
