Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium.
Vet Res. 2019 Dec 19;50(1):110. doi: 10.1186/s13567-019-0728-x.
Intestinal epithelium functions as a barrier to protect multicellular organisms from the outside world. It consists of epithelial cells closely connected by intercellular junctions, selective gates which control paracellular diffusion of solutes, ions and macromolecules across the epithelium and keep out pathogens. Rotavirus is one of the major enteric viruses causing severe diarrhea in humans and animals. It specifically infects the enterocytes on villi of small intestines. The polarity of rotavirus replication in their target enterocytes and the role of intestinal epithelial integrity were examined in the present study. Treatment with EGTA, a drug that chelates calcium and disrupts the intercellular junctions, (i) significantly enhanced the infection of rotavirus in primary enterocytes, (ii) increased the binding of rotavirus to enterocytes, but (iii) considerably blocked internalization of rotavirus. After internalization, rotavirus was resistant to EGTA treatment. To investigate the polarity of rotavirus infection, the primary enterocytes were cultured in a transwell system and infected with rotavirus at either the apical or the basolateral surface. Rotavirus preferentially infected enterocytes at the basolateral surface. Restriction of infection through apical inoculation was overcome by EGTA treatment. Overall, our findings demonstrate that integrity of the intestinal epithelium is crucial in the host's innate defense against rotavirus infection. In addition, the intercellular receptor is located basolaterally and disruption of intercellular junctions facilitates the binding of rotavirus to their receptor at the basolateral surface.
肠上皮作为一道屏障，保护多细胞生物免受外界侵害。它由上皮细胞通过细胞间连接紧密连接而成，这些连接是选择性的门，控制溶质、离子和大分子穿过上皮的旁细胞扩散，并阻止病原体进入。轮状病毒是导致人类和动物严重腹泻的主要肠道病毒之一。它专门感染小肠绒毛上的肠细胞。本研究检查了轮状病毒在其靶肠细胞中的复制极性和肠上皮完整性的作用。用 EGTA（一种螯合钙并破坏细胞间连接的药物）处理（i）显著增强了原代肠细胞中轮状病毒的感染，（ii）增加了轮状病毒与肠细胞的结合，但（iii）严重阻断了轮状病毒的内化。内化后，轮状病毒能抵抗 EGTA 的处理。为了研究轮状病毒感染的极性，将原代肠细胞在 Transwell 系统中培养，并在顶端或基底外侧表面感染轮状病毒。轮状病毒优先感染基底外侧表面的肠细胞。通过顶端接种限制感染被 EGTA 处理克服。总的来说，我们的发现表明肠上皮的完整性对于宿主先天防御轮状病毒感染至关重要。此外，细胞间受体位于基底外侧，细胞间连接的破坏促进了轮状病毒与其在基底外侧表面的受体的结合。
