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Insights into IAV Replication and Lipid Metabolism in Suspension-Adapted MDCK-STAT1-KO Cells
Qian Ye1,2, Hong Yao1,2, Zhiying Xiao1,2
1State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
Objectives:
The industrial production of influenza vaccines is facing significant challenges, particularly in improving virus production efficiency. Despite advances in cell culture technologies, our understanding of the production characteristics of high-yield suspension cell lines remains limited, thereby impeding the development of efficient vaccine production platforms. This study aims to investigate the key features of STAT1 knockout suspension-adapted MDCK cells (susMDCK-STAT1-KO) in enhancing influenza A virus (IAV) production.
Methods:
Suspension-adapted susMDCK-STAT1-KO cells were compared to suspension-adapted wild-type MDCK cells (susMDCK) for IAV production. Virus quantification, gene expression analysis, and cholesterol deprivation assays were performed. Metabolite profiles, viral RNA quantification, and lipid and dry weight measurements were also conducted to assess the viral replication and release efficiency.
Results:
The susMDCK-STAT1-KO cells exhibited significantly improved virus adsorption (64%) and entry efficiency (75%) for the H1N1 virus, as well as accelerated viral transcription and replication for both the H1N1 and H9N2 viruses. Virus release was identified as a limiting factor, with a 100-fold higher intracellular-to-extracellular viral RNA ratio. However, the STAT1-KO cells showed a 2.39-fold higher release rate (750 virions/cell/h) and 3.26-fold greater RNA release for the H1N1 virus compared to wild-type cells. A gene expression analysis revealed enhanced lipid metabolism, particularly cholesterol synthesis, as a key factor in viral replication and release. Cholesterol deprivation resulted in reduced viral titers, confirming the critical role of intracellular cholesterol in IAV production.
Conclusions:
This study demonstrates the enhanced influenza virus production capacity of susMDCK-STAT1-KO cells, with significant improvements in viral yield, replication, and release efficiency. The findings highlight the importance of STAT1-mediated immune modulation and cholesterol metabolism in optimizing virus production. These insights provide a foundation for the development of more efficient vaccine production platforms, with implications for large-scale industrial applications.
