Autophagy induced by Vip3Aa has a pro-survival role in Spodoptera frugiperda Sf9 cells

Xiaoyue Hou; Lu Han; Baoju An; Jun Cai

doi:10.1080/21505594.2021.1878747

Autophagy induced by Vip3Aa has a pro-survival role in Spodoptera frugiperda Sf9 cells

Virulence. 2021 Dec;12(1):509-519. doi: 10.1080/21505594.2021.1878747.

Authors

Xiaoyue Hou^{1

2

3}, Lu Han¹, Baoju An¹, Jun Cai^{1

4

5}

Affiliations

¹ Department of Microbiology, College of Life Sciences, Nankai University , Tianjin, China.
² Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University , Lianyungang, China.
³ College of Food Science and Engineering, Jiangsu Ocean University , Lianyungang, China.
⁴ Key Laboratory of Molecular Microbiology and Technology, Ministry of Education , Tianjin, China.
⁵ Tianjin Key Laboratory of Microbial Functional Genomics , Tianjin, China.

Abstract

Vip3Aa is an insecticidal protein that can effectively control certain lepidopteran pests and has been used widely in biological control. However, the mechanism of action of Vip3Aa is unclear. In the present study, we showed that Vip3Aa could cause autophagy in Sf9 cells, which was confirmed by the increased numbers of GFP-Atg8 puncta, the appearance of autophagic vacuoles, and an elevated Atg8-II protein level. Moreover, we found that the AMPK-mTOR-ULK1 pathway is involved in Vip3Aa-induced autophagy, which might be associated with the destruction of ATP homeostasis in Vip3Aa-treated cells. Both the elevated p62 level and the increased numbers of GFP-RFP-Atg8 yellow fluorescent spots demonstrated that autophagy in Sf9 cells was inhibited at 24 h after Vip3Aa treatment. With the prolongation of Vip3Aa treatment time, this inhibition became more serious and led to autophagosome accumulation. Genetic knockdown of ATG5 or the use of the autophagy inhibitor 3-MA further increased the sensitivity of Sf9 cells to Vip3Aa. Overexpression of ATG5 reduced the cell mortality of Vip3Aa-treated cells. In summary, the results revealed that autophagy induced by Vip3Aa has a pro-survival role, which might be related to the development of insect resistance.

Keywords: Vip3Aa; atg5; autophagosome; autophagy; sf9 cells.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Autophagy / drug effects*
Autophagy-Related Protein 5 / genetics
Bacterial Proteins / genetics
Bacterial Proteins / pharmacology*
Sf9 Cells / drug effects*
Spodoptera / cytology*

Substances

Autophagy-Related Protein 5
Bacterial Proteins

Grants and funding

This work was supported by the National Natural Science Foundation of China [31371979]; National Key R&D Program of China [2017YFD0200400]; Innovative Research Group Project of the National Natural Science Foundation of China (CN) [31670081].