1. Academic Validation
  2. Non-Structural Protein 3 of Duck Tembusu Virus Induces Autophagy via the ERK and PI3K-AKT-mTOR Signaling Pathways

Non-Structural Protein 3 of Duck Tembusu Virus Induces Autophagy via the ERK and PI3K-AKT-mTOR Signaling Pathways

  • Front Immunol. 2022 Feb 3;13:746890. doi: 10.3389/fimmu.2022.746890.
Jun Zhao 1 Tingting Zhang 1 2 Guomin Chen 3 Ningwei Geng 1 Zhiyun Guo 1 Shengliang Cao 1 Yudong Yang 1 Kuihao Liu 1 Siqi Wang 1 Yiran Zhao 1 Fanliang Meng 1 Sidang Liu 1 Meijie Jiang 4 Ning Li 1 5
Affiliations

Affiliations

  • 1 Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, College of Animal Science and Technology, Shandong Agricultural University, Taian City, China.
  • 2 Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, College of Basic Medical Sciences, Shandong First Medical University, Taian City, China.
  • 3 Laboratory Medicine, Central Hospital Affiliated to Shandong First Medical University, Jinan, China.
  • 4 Laboratory Medicine, Tai'an City Central Hospital, Taian, China.
  • 5 Sino-German Cooperative Research Centre for Zoonosis of Animal Origin Shandong Province, Shandong Agricultural University, Taian City, China.
Abstract

Despite autophagy's pivotal role in the replication of viruses such as duck Tembusu virus (DTMUV), which has caused massive economic losses to the poultry industry in the world, the specific relationships between DTMUV and cellular Autophagy remain largely unknown. In response, we investigated the interactions between Autophagy and DTMUV, the effects of the structural and non-structural proteins of DTMUV on Autophagy, and the autophagy-related signaling pathways induced by DTMUV. Among the results, DTMUV increased the Autophagy flux in duck embryo fibroblasts (DEF) and BHK-21 cells, while Autophagy facilitated viral replication. After we pharmacologically induced Autophagy with rapamycin (RAPA), the replication of DTMUV increased by 15.23-fold compared with the control group of DEF cells. To identify which DTMUV protein primarily induced Autophagy, all three structural proteins and seven non-structural proteins of DTMUV were transfected into cells, and the results showed that non-structural protein 3 (NS3) induced significant Autophagy in DEF cells. By means of Western blot, immunofluorescence, and transmission electron microscopy, we confirmed that NS3 protein could significantly induce Autophagy and Autophagy flux. Furthermore, we showed that NS3 induced Autophagy in DEF cells through extracellular signal-regulated kinase 2 (ERK2) and phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) signaling pathways using specific inhibitors and RNA interference assays. Finally, Autophagy induced by NS3 promoted DTMUV replication. These results provide novel insight into the relationship between DTMUV and Autophagy, broadening the current understanding of the molecular pathogenesis of DTMUV.

Keywords

ERK2; PI3K-AKT-mTOR; autophagy; duck Tembusu virus; non-structural protein 3; virus replication.

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