Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
Infect Immun. 2018 Mar 22;86(4). doi: 10.1128/IAI.00582-17. Print 2018 Apr.
Rats vary in their susceptibilities to infection depending on the rat strain. Compared to the -susceptible Brown Norway (BN) rat, the Lewis (LEW) rat is extremely resistant to Thus, these two rat strains are ideal models for elucidating host mechanisms that are important for host resistance to infection. Therefore, in our efforts to unravel molecular factors directing the protective early innate immune response in the LEW rat, we performed RNA sequencing analysis of the LEW versus BN rat with or without infection. We identified three candidate small TPase munity-ssociated roteins (GIMAPs) that were upregulated (false discovery rate, 0.05) in the LEW rat in response to infection. Subsequently, we engineered -susceptible NR8383 rat macrophage cells for overexpression of LEW rat-derived candidate GIMAP 4, 5, and 6. By immunofluorescence analysis we observed that GIMAP 4, 5, and 6 in -infected NR8383 cells each colocalized with GRA5, a parasite parasitophorous vacuole membrane (PVM) marker protein, suggesting their translocation to the PVM. Interestingly, overexpression of each candidate GIMAP in -infected NR8383 cells induced translocation of LAMP1, a lysosome marker protein, to the surface membrane. Importantly, overexpression of GIMAP 4, 5, or 6 individually inhibited intracellular growth, with GIMAP 4 having the highest inhibitory effect. Together, our findings indicate that upregulation of GIMAP 4, 5, and 6 contributes to the robust refractoriness of the LEW rat to through induction of lysosomal fusion to the otherwise nonfusogenic PVM.
大鼠对感染的易感性因大鼠品系而异。与易感的棕色挪威（BN）大鼠相比，刘易斯（LEW）大鼠对感染极为抵抗。因此，这两种大鼠品系是阐明宿主对抗感染的宿主机制的理想模型。因此，为了阐明指导 LEW 大鼠保护性早期先天免疫反应的分子因素，我们对感染前后的 LEW 和 BN 大鼠进行了 RNA 测序分析。我们发现了三个候选小 TPase munity-ssociated roteins（GIMAPs），它们在 LEW 大鼠中对感染呈上调表达（错误发现率，0.05）。随后，我们对易感的 NR8383 大鼠巨噬细胞进行了基因工程改造，以过度表达来自 LEW 大鼠的候选 GIMAP4、5 和 6。通过免疫荧光分析，我们观察到 GIMAP4、5 和 6 在感染的 NR8383 细胞中与寄生虫寄生空泡膜（PVM）标记蛋白 GRA5 共定位，表明它们向 PVM 转移。有趣的是，在感染的 NR8383 细胞中过度表达每个候选 GIMAP 都会诱导溶酶体标记蛋白 LAMP1 向 表面膜的易位。重要的是，GIMAP4、5 或 6 的单独过表达均抑制了细胞内的生长，其中 GIMAP4 的抑制作用最高。总之，我们的研究结果表明，GIMAP4、5 和 6 的上调有助于 LEW 大鼠对感染的强烈抵抗力，这是通过诱导溶酶体与非融合性 PVM 融合实现的。
