Trinh Quang Duy, Takada Kazuhide, Pham Ngan Thi Kim, Takano Chika, Namiki Takahiro, Ikuta Ryo, Hayashida Shingo, Okitsu Shoko, Ushijima Hiroshi, Komine-Aizawa Shihoko, Hayakawa Satoshi
Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan.
Nihon University School of Medicine, Tokyo, Japan.
Front Microbiol. 2022 Jul 8;13:904189. doi: 10.3389/fmicb.2022.904189. eCollection 2022.
Rubella virus (RuV) infections in pregnant women, especially first-trimester infections, can lead to congenital rubella syndrome (CRS). However, the mechanisms of fetal RuV infection are not completely understood, and it is not observed in every pregnant woman infected with RuV. As gestational diabetes mellitus is a risk factor for congenital viral infections, we investigated the possible roles of hypoglycemia-related endoplasmic reticulum (ER) stress as a key factor for vertical RuV infection using immortalized human first-trimester trophoblasts. Low-glucose stress was induced prior to RuV infection by culturing HTR-8/SVneo and Swan.71 cells in low-glucose (LG) medium for 24 h or high-glucose medium for 6 h and then LG medium for an additional 18 h. Clinically isolated RuV was inoculated at a multiplicity of infection of 5 to 10. The intracellular localization of the RuV capsid protein was investigated 24 to 48 h post-infection (pi) with flow cytometry (FCM) analysis and fluorescence microscopy. Viral progeny production was monitored by FCM analysis. Increases in RuV infection in LG-induced ER-stressed trophoblasts were observed. No significant increase in apoptosis of RuV-infected cells was noted at days 2 and 5 pi, and substantial viral progeny production was observed until day 5 pi. An approximate fivefold increase in viral binding was noted for the LG-stressed cells. Although the detailed mechanisms underlying viral entry into LG-stressed cells are not known and require further investigation, these findings suggest that a certain degree of LG stress in early pregnancy may facilitate infection and cause CRS.
孕妇感染风疹病毒（RuV），尤其是孕早期感染，可导致先天性风疹综合征（CRS）。然而，胎儿感染RuV的机制尚未完全明确，且并非每个感染RuV的孕妇都会出现这种情况。由于妊娠期糖尿病是先天性病毒感染的一个危险因素，我们使用永生化的人孕早期滋养层细胞，研究了低血糖相关内质网（ER）应激作为垂直RuV感染关键因素的可能作用。在RuV感染前，通过将HTR-8/SVneo和Swan.71细胞在低糖（LG）培养基中培养24小时，或在高糖培养基中培养6小时，然后再在LG培养基中培养18小时，诱导低葡萄糖应激。以5至10的感染复数接种临床分离的RuV。在感染后24至48小时（pi），通过流式细胞术（FCM）分析和荧光显微镜检查RuV衣壳蛋白的细胞内定位。通过FCM分析监测病毒子代的产生。观察到LG诱导的内质网应激滋养层细胞中RuV感染增加。在感染后第2天和第5天，未观察到RuV感染细胞凋亡的显著增加，并且直到感染后第5天观察到大量病毒子代产生。LG应激细胞的病毒结合增加了约五倍。尽管病毒进入LG应激细胞的详细机制尚不清楚，需要进一步研究，但这些发现表明，孕早期一定程度的LG应激可能促进感染并导致CRS。
