Sheng Gang, Chu Hongqian, Duan Huijuan, Wang Wenjing, Tian Na, Liu Dingyi, Sun Hong, Sun Zhaogang
Beijing Chest Hospital Affiliated to Capital Medical University, Beijing 100000, China.
Beijing Thoracic Tumor and Tuberculosis Institute, Beijing 100000, China.
Microorganisms. 2023 Oct 5;11(10):2500. doi: 10.3390/microorganisms11102500.
Leucine-rich repeat-containing protein-25 (LRRC25) can degrade the ISG15 gene in virus-infected cells and prevent overactivation of the type Ⅰ IFN pathway. However, the role of LRRC25 in bacterial infection is still unclear. In this pursuit, the present study aimed to explore the regulatory role and mechanism of LRRC25 in microglia infected with in a mouse model.
Q-PCR, WB, and cell immunofluorescence were employed to observe the change in LRRC25 in BV2 cells infected by H37Rv. Additionally, siRNA was designed to target the LRRC25 to inhibit its expression in BV2 cells. Flow cytometry and laser confocal imaging were used to observe the infection of BV2 cells after LRRC25 silencing. Q-PCR and ELISA were used to determine the changes in IFN-γ and ISG15 in the culture supernatant of each group.
Following H37Rv infection, it was observed that the expression of LRRC25 was upregulated. Upon silencing LRRC25, the proportion of BV2 cells infected by H37Rv decreased significantly. ELISA analysis showed that IFN-γ and ISG15 levels in cell culture supernatant decreased after H37Rv infection, while they significantly increased after LRRC25 silencing.
This study provides evidence that LRRC25 is the key negative regulator of microglial anti- immunity. It exerts its function by degrading free ISG15 and inhibiting the secretion of IFN-γ, thereby improving the anti-Mtb immunity of BV2 cells.
富含亮氨酸重复序列蛋白25（LRRC25）可在病毒感染的细胞中降解ISG15基因，并防止Ⅰ型干扰素途径过度激活。然而，LRRC25在细菌感染中的作用仍不清楚。在此研究中，本研究旨在探讨LRRC25在小鼠模型中感染结核杆菌的小胶质细胞中的调节作用及机制。
采用Q-PCR、WB和细胞免疫荧光法观察H37Rv感染的BV2细胞中LRRC25的变化。此外，设计针对LRRC25的siRNA以抑制其在BV2细胞中的表达。采用流式细胞术和激光共聚焦成像观察LRRC25沉默后BV2细胞的感染情况。采用Q-PCR和ELISA法检测各组培养上清中IFN-γ和ISG15的变化。
H37Rv感染后，观察到LRRC25的表达上调。沉默LRRC25后，H37Rv感染的BV2细胞比例显著降低。ELISA分析显示，H37Rv感染后细胞培养上清中IFN-γ和ISG15水平降低，而LRRC25沉默后显著升高。
本研究提供了证据表明LRRC25是小胶质细胞抗感染免疫的关键负调节因子。它通过降解游离的ISG15并抑制IFN-γ的分泌发挥其功能，从而提高BV2细胞的抗结核分枝杆菌免疫力。
