Dengue virus (DENV) is the most prevalent pathogen of the Flaviviridae family. Due to the considerable increase in DENV incidence and spread, symptoms such as CNS involvement have increased. Heparan sulphate (HS) was the first molecule identified as an adhesion factor for DENV in mammalian cells. Viral phenotypes with different HS interactions are associated with various clinical symptoms, including neurological alterations. Here, using in silico analyses, in vitro studies, and the in vivo mouse model, we characterized two natural circulating DENV3 genotype I (GI) lineage 1 (L1) in Brazil–DENV3 MG-20 (from Minas Gerais) and DENV3 PV_BR (from Rondônia) that present divergent neurovirulent profiles and sensitivity to sulphated molecules. We identified substitutions at the viral envelope (E) in positions 62 and 123 as likely responsible for the differences in neurovirulence. The E62K and E123Q substitutions in DENV3 MG-20 and DENV3 PV_BR, respectively, greatly influenced in silico electrostatic density and heparin docking results. In vivo, mice inoculated with DENV3 MG-20 died, but not those infected with DENV3 PV_BR. The clinical symptoms, such as paralysis of the lower limbs and meningoencephalitis, and histopathology, also differed between the inoculated groups. In vitro heparin and heparinases assays further demonstrated the biological impact of these substitutions. Other characteristics that have been previously associated with alterations in cell tropism and neurovirulence, such as changes in the size of lysis plaques and differences in cytopathic effects in glioblastoma cells, were also observed.

中文翻译：

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登革热病毒 3 基因型 I 显示小鼠模型中硫酸乙酰肝素结合位点、细胞相互作用和神经毒力的自然变化

登革热病毒 (DENV) 是黄病毒科最流行的病原体。由于 DENV 发病率和传播的显着增加，中枢神经系统受累等症状有所增加。硫酸乙酰肝素 (HS) 是第一个被鉴定为哺乳动物细胞中 DENV 粘附因子的分子。具有不同 HS 相互作用的病毒表型与各种临床症状有关，包括神经系统改变。在这里，使用计算机分析、体外研究和体内在小鼠模型中，我们表征了巴西的两个自然循环 DENV3 基因型 I (GI) 谱系 1 (L1)–DENV3 MG-20（来自米纳斯吉拉斯州）和 DENV3 PV_BR（来自朗多尼亚州），它们呈现出不同的神经毒性特征和对硫酸化分子的敏感性。我们确定病毒包膜 (E) 位置 62 和 123 处的替换可能是造成神经毒力差异的原因。DENV3 MG-20 和 DENV3 PV_BR 中的 E62K 和 E123Q 取代分别极大地影响了硅静电密度和肝素对接结果。在体内，接种 DENV3 MG-20 的小鼠死亡，但感染 DENV3 PV_BR 的小鼠没有死亡。接种组之间的临床症状，例如下肢麻痹和脑膜脑炎，以及组织病理学也不同。体外肝素和肝素酶测定进一步证明了这些替代的生物学影响。还观察到以前与细胞趋向性和神经毒力改变相关的其他特征，例如裂解斑块大小的变化和胶质母细胞瘤细胞中细胞病变效应的差异。