Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
J Biomed Sci. 2024 Jan 17;31(1):8. doi: 10.1186/s12929-024-00995-x.
Chikungunya virus (CHIKV) has reemerged as a major public health concern, causing chikungunya fever with increasing cases and neurological complications.
In the present study, we investigated a low-passage human isolate of the East/ Central/South African (ECSA) lineage of CHIKV strain LK(EH)CH6708, which exhibited a mix of small and large viral plaques. The small and large plaque variants were isolated and designated as CHIKV-SP and CHIKV-BP, respectively. CHIKV-SP and CHIKV-BP were characterized in vitro and in vivo to compare their virus production and virulence. Additionally, whole viral genome analysis and reverse genetics were employed to identify genomic virulence factors.
CHIKV-SP demonstrated lower virus production in mammalian cells and attenuated virulence in a murine model. On the other hand, CHIKV-BP induced higher pro-inflammatory cytokine levels, compromised the integrity of the blood-brain barrier, and led to astrocyte infection in mouse brains. Furthermore, the CHIKV-SP variant had limited transmission potential in Aedes albopictus mosquitoes, likely due to restricted dissemination. Whole viral genome analysis revealed multiple genetic mutations in the CHIKV-SP variant, including a Glycine (G) to Arginine (R) mutation at position 55 in the viral E2 glycoprotein. Reverse genetics experiments confirmed that the E2-G55R mutation alone was sufficient to reduce virus production in vitro and virulence in mice.
These findings highlight the attenuating effects of the E2-G55R mutation on CHIKV pathogenicity and neurovirulence and emphasize the importance of monitoring this mutation in natural infections.
基孔肯雅病毒（CHIKV）再次成为一个主要的公共卫生关注点，导致基孔肯雅热病例不断增加，并伴有神经系统并发症。
在本研究中，我们研究了一株来自东/中非/南非（ECSA）谱系的低代人分离株 CHIKV 株 LK(EH)CH6708，其表现出小和大病毒斑的混合。从小和大斑块中分离出变体，并分别命名为 CHIKV-SP 和 CHIKV-BP。对 CHIKV-SP 和 CHIKV-BP 进行了体外和体内特征分析，以比较它们的病毒产量和毒力。此外，还进行了全病毒基因组分析和反向遗传学，以鉴定基因组毒力因子。
CHIKV-SP 在哺乳动物细胞中的病毒产量较低，在小鼠模型中的毒力减弱。另一方面，CHIKV-BP 诱导更高水平的促炎细胞因子，破坏血脑屏障的完整性，并导致小鼠大脑中的星形胶质细胞感染。此外，CHIKV-SP 变体在白纹伊蚊中的传播潜力有限，可能是由于传播受限。全病毒基因组分析显示，CHIKV-SP 变体存在多个遗传突变，包括病毒 E2 糖蛋白第 55 位甘氨酸（G）突变为精氨酸（R）。反向遗传学实验证实，E2-G55R 突变单独足以降低病毒在体外的产量和在小鼠中的毒力。
这些发现强调了 E2-G55R 突变对 CHIKV 致病性和神经毒力的减弱作用，并强调了在自然感染中监测这种突变的重要性。
