Esmael Ahmed, Petro Thomas M
Nebraska Center for Virology, University of Nebraska Lincoln, Lincoln, NE 68583, USA; Botany and Microbiology Department, Faculty of Science, Benha University, Benha 13518, Egypt.
Nebraska Center for Virology, University of Nebraska Lincoln, Lincoln, NE 68583, USA; Dept. of Oral Biology, University of Nebraska Medical Center, Lincoln, NE, 68583, USA.
Virus Res. 2023 Jan 2;323:199007. doi: 10.1016/j.virusres.2022.199007. Epub 2022 Nov 19.
Interleukin-33 (IL-33), which promotes M2 macrophage development, may influence the control of viruses, such as Theiler's Murine Encephalomyelitis Virus (TMEV) that infect macrophages. Because Interferon Regulatory Factor-3 (IRF3) is also critical to control of TMEV infection in macrophages, information on the relationship between IL-33 and IRF3 is important. Thus, RAW264.7 Lucia murine macrophage lineage cells with an endogenous IRF3-ISRE promoter driving secreted luciferase and IRF3KO RAW Lucia, a subline deficient in IRF3, were challenged with TMEV. After the challenge, considerable TMEV RNA detected at 18 and 24 h in RAW cells was significantly elevated in IRF3KO RAW cells. TMEV induction of ISRE-IRF3 promoter activity, IFN-β and IL-33 gene expression, and IL-6 and IL-10 protein production, which was strong in RAW cells, was less in IRF3KO RAW cells. In contrast, expression of CD206 and ARG1, classical M2 macrophage markers, was significantly elevated in IRF3KO RAW cells. Moreover, RAW and IRF3KO RAW cells produced extracellular IL-33 prior to and after infection with TMEV and antibody blockade of the IL-33 receptor, ST2, reduced CD206 and ARG1 expression, but increased IL-6 gene expression. Pre-treating both RAW and IRF3KO RAW cells with IL-33 prior to challenge significantly increased TMEV infection, but also increased IL-33, IL-10, IL-6 mRNA expression, and NO production without increasing IFN-β. Notably, IL-33 induction of IL-33, IRF3-ISRE promoter activity, and IL-10 by TMEV or poly I:C/IFN-γ was significantly dependent upon IRF3. The results show that the expression of IL-33 and the repression of M2 macrophage phenotypic markers are dependent on IRF3 and that IL-33 decreases the ability of macrophages to control infection with macrophage-tropic viruses.
促进M2巨噬细胞发育的白细胞介素-33（IL-33）可能会影响对病毒的控制，比如感染巨噬细胞的泰勒氏鼠脑脊髓炎病毒（TMEV）。由于干扰素调节因子-3（IRF3）对巨噬细胞中TMEV感染的控制也至关重要，因此有关IL-33与IRF3之间关系的信息很重要。于是，用TMEV对具有驱动分泌型荧光素酶的内源性IRF3-ISRE启动子的RAW264.7 Lucia小鼠巨噬细胞系细胞以及IRF3基因敲除的RAW Lucia（一种IRF3缺陷的亚系细胞）进行攻击。攻击后，RAW细胞在18小时和24小时检测到的大量TMEV RNA在IRF3基因敲除的RAW细胞中显著升高。TMEV对ISRE-IRF3启动子活性、IFN-β和IL-33基因表达以及IL-6和IL-10蛋白产生的诱导作用在RAW细胞中很强，但在IRF3基因敲除的RAW细胞中较弱。相反，经典M2巨噬细胞标志物CD206和ARG1的表达在IRF3基因敲除的RAW细胞中显著升高。此外，RAW和IRF3基因敲除的RAW细胞在感染TMEV之前和之后都会产生细胞外IL-33，并且对IL-33受体ST2的抗体阻断会降低CD206和ARG1的表达，但会增加IL-6基因表达。在攻击前用IL-33预处理RAW和IRF3基因敲除的RAW细胞，显著增加了TMEV感染，但也增加了IL-33、IL-10、IL-6 mRNA表达以及一氧化氮（NO）的产生，而没有增加IFN-β。值得注意的是，TMEV或聚肌胞苷酸/干扰素-γ对IL-33、IRF3-ISRE启动子活性和IL-10的诱导作用显著依赖于IRF3。结果表明，IL-33的表达以及M2巨噬细胞表型标志物的抑制依赖于IRF3，并且IL-33会降低巨噬细胞控制嗜巨噬细胞病毒感染的能力。
