Hee Jing-Ru, Cheng Dayna, Chen Yu-Hong, Wang Sheng-Hsuan, Chao Chiao-Hsuan, Huang Sheng-Wen, Ling Pin, Wan Shu-Wen, Chang Chih-Peng, Chu Justin Jang Hann, Yeh Trai-Ming, Wang Jen-Ren
Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan, 701, Taiwan.
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
J Biomed Sci. 2025 Feb 20;32(1):25. doi: 10.1186/s12929-024-01116-4.
The largest dengue virus 2 (DENV2) outbreak occurred in Taiwan in 2015, resulting in many fatalities. We therefore aim to identify crucial genetic variations which determine the virulence of the 2015 Taiwan outbreak strains.
We compared the 2015 Taiwan DENV2 sequences to the pre-2015 sequences. Reverse genetics (rg) viruses with substitutions were produced and the viral growth kinetics were investigated. We treated A549 cells with interferon (IFN) to determine the interferon-stimulated genes (ISGs) expression and STAT1 phosphorylation in the rg viral infection and plasmid transfection systems. IFN and pro-inflammatory cytokines levels were measured upon DENV infection using ELISA.
The rgNS1-K272R mutant showed faster replication in IFN-I producing cells compared to wildtype (WT) virus. Results revealed that NS1-K272R substitution contributed to higher soluble NS1 secretion and evade the antiviral response by suppressing the expression of ISGs and STAT1 phosphorylation compared to NS1-WT. Infection with rgNS1-K272R induced higher secretion of pro-inflammatory cytokines through the activation of canonical nuclear factor-kappa B (NF-κB) signaling pathway.
Our results revealed that the DENV NS1 amino acid substitution affects the NS1 ability in immune evasion, which may contribute to the largest dengue outbreak in Taiwan since the 1990s.
2015年台湾发生了最大规模的登革热病毒2型（DENV2）疫情，导致许多人死亡。因此，我们旨在确定决定2015年台湾疫情毒株毒力的关键基因变异。
我们将2015年台湾DENV2序列与2015年前的序列进行了比较。构建了带有替换突变的反向遗传学（rg）病毒，并研究了病毒的生长动力学。我们用干扰素（IFN）处理A549细胞，以确定rg病毒感染和质粒转染系统中干扰素刺激基因（ISGs）的表达和STAT1磷酸化情况。使用酶联免疫吸附测定法（ELISA）测量登革热病毒感染后IFN和促炎细胞因子的水平。
与野生型（WT）病毒相比，rgNS1-K272R突变体在产生I型干扰素的细胞中复制更快。结果显示，与NS1-WT相比，NS1-K272R替换导致更高的可溶性NS1分泌，并通过抑制ISGs的表达和STAT1磷酸化来逃避抗病毒反应。rgNS1-K272R感染通过激活经典的核因子-κB（NF-κB）信号通路诱导更高水平的促炎细胞因子分泌。
我们的结果表明，登革热病毒NS1氨基酸替换会影响NS1的免疫逃逸能力，这可能是导致台湾自20世纪90年代以来最大规模登革热疫情的原因之一。
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