Objective

Mycoplasma gallisepticum (MG), a notorious avian pathogen, leads to considerable economic losses in the poultry industry. MG infection is characterized by severe, uncontrollable inflammation and host DNA damage. Micro ribonucleic acids (miRNAs) have emerged as important regulators in microbial pathogenesis. However, the role of miRNAs in MG infection is poorly characterized. In this study, we validated the functional roles of gga-miR-142-3p.

Methods

The relative expression of gga-miR-142-3p in the lungs of the MG-infected chicken embryos and the MG-infected chicken embryonic fibroblast cell line (DF-1) was determined by reverse transcription quantitative real-time PCR analysis. Bioinformatics database was used to analysis the target gene of gga-miR-142-3p. The luciferase reporter assay as well as gene expression analysis were conducted to validate the target gene. To further explore the biological functions of gga-miR-142-3p upon MG infection, the cell proliferation was quantified using Cell Counting Kit-8 (CCK-8). Meanwhile, cell cycle analysis and apoptosis were measured using a flow cytometer.

Results

gga-miR-142-3p was significantly upregulated in both MG-infected chicken-embryo lungs and the DF-1 cells. gga-miR-142-3p over expression significantly downregulated the expression of pro-inflammatory cytokines, including interleukin-1β, interleukin-6 and tumor necrosis factor alpha after MG infection. Meanwhile, gga-miR-142-3p enhanced the host defense against MG infection by facilitating cell proliferation, promoting cell progression and inhibiting cell apoptosis. Interestingly, TAB2 knockdown groups show similar results, whereas, TAB2 over-expression groups and gga-miR-142-3p inhibitor groups had thoroughly opposite results. The expression of p-p65 in nuclear factor kappa B (NF-κB) and p-p38 in the mitogen-activated protein kinase (MAPK) pathway was decreased when gga-miR-142-3p was over-expressed.

Conclusion

Upon MG infection, upregulation of gga-miR-142-3p alleviates inflammation by negatively regulating the signaling pathways of NF-κB and MAPKs by targeting TAB2 and facilitates cell proliferation by inhibiting cell apoptosis and promoting cell cycle progression to defend against MG infection.

中文翻译：

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gga-miR-142-3p 通过靶向 TAB2 的 NF-κB 和 MAPK 信号传导负调节鸡毒支原体（HS 株）诱导的炎性细胞因子产生

客观的

鸡毒支原体(MG) 是一种臭名昭著的禽类病原体，给家禽业造成了相当大的经济损失。MG 感染的特点是严重的、无法控制的炎症和宿主 DNA 损伤。微核糖核酸 (miRNA) 已成为微生物发病机制中的重要调节因子。然而，miRNA 在 MG 感染中的作用尚不明确。在这项研究中，我们验证了 gga-miR-142-3p 的功能作用。

方法

gga-miR-142-3p 在 MG 感染的鸡胚胎和 MG 感染的鸡胚胎成纤维细胞系 (DF-1) 的肺中的相对表达通过逆转录定量实时 PCR 分析确定。使用生物信息学数据库分析gga-miR-142-3p的靶基因。进行荧光素酶报告基因测定以及基因表达分析以验证靶基因。为了进一步探索 gga-miR-142-3p 在 MG 感染后的生物学功能，使用 Cell Counting Kit-8 (CCK-8) 量化细胞增殖。同时，使用流式细胞仪测量细胞周期分析和细胞凋亡。

结果

gga-miR-142-3p 在 MG 感染的鸡胚胎肺和 DF-1 细胞中均显着上调。gga-miR-142-3p 过表达显着下调促炎细胞因子的表达，包括 MG 感染后的白细胞介素-1β、白细胞介素-6 和肿瘤坏死因子α。同时，gga-miR-142-3p通过促进细胞增殖、促进细胞进展和抑制细胞凋亡来增强宿主对MG感染的防御。有趣的是，TAB2 敲低组显示出相似的结果，而 TAB2 过表达组和 gga-miR-142-3p 抑制剂组的结果完全相反。当 gga-miR-142-3p 过表达时，p-p65 在核因子 kappa B (NF-κB) 和 p-p38 在丝裂原活化蛋白激酶 (MAPK) 通路中的表达降低。

结论

MG感染后，gga-miR-142-3p的上调通过靶向TAB2负调节NF-κB和MAPKs的信号通路减轻炎症，并通过抑制细胞凋亡和促进细胞周期进程促进细胞增殖以防御MG感染。