College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China.
State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
J Virol. 2023 May 31;97(5):e0029223. doi: 10.1128/jvi.00292-23. Epub 2023 May 3.
Chemokine production by epithelial cells is crucial for neutrophil recruitment to sites of inflammation during viral infection. However, the effect of chemokine on epithelia and how chemokine is involved in coronavirus infection remains to be fully understood. Here, we identified an inducible chemokine interleukin-8 (CXCL8/IL-8), which could promote coronavirus porcine epidemic diarrhea virus (PEDV) infection in African green monkey kidney epithelial cells (Vero) and Lilly Laboratories cell-porcine kidney 1 epithelial cells (LLC-PK1). IL-8 deletion restrained cytosolic calcium (Ca), whereas IL-8 stimulation improved cytosolic Ca. The consumption of Ca restricted PEDV infection. PEDV internalization and budding were obvious reductions when cytosolic Ca was abolished in the presence of Ca chelators. Further study revealed that the upregulated cytosolic Ca redistributes intracellular Ca. Finally, we identified that G protein-coupled receptor (GPCR)-phospholipase C (PLC)-inositol trisphosphate receptor (IP3R)-store-operated Ca (SOC) signaling was crucial for enhancive cytosolic Ca and PEDV infection. To our knowledge, this study is the first to uncover the function of chemokine IL-8 during coronavirus PEDV infection in epithelia. PEDV induces IL-8 expression to elevate cytosolic Ca, promoting its infection. Our findings reveal a novel role of IL-8 in PEDV infection and suggest that targeting IL-8 could be a new approach to controlling PEDV infection. Coronavirus porcine epidemic diarrhea virus (PEDV) is a highly contagious enteric coronavirus that caused severe economic losses worldwide, and more effort is needed to develop economical and efficient vaccines to control or eliminate this disease. The chemokine interleukin-8 (CXCL8/IL-8) is indispensable for the activation and trafficking of inflammatory mediators and tumor progression and metastasis. This study evaluated the effect of IL-8 on PEDV infection in epithelia. We found that IL-8 expression improved cytosolic Ca in epithelia, facilitating PEDV rapid internalization and egress. G protein-coupled receptor (GPCR)-phospholipase C (PLC)-inositol trisphosphate receptor (IP3R)-SOC signaling was activated by IL-8, releasing the intracellular Ca stores from endoplasmic reticulum (ER). These findings provide a better understanding of the role of IL-8 in PEDV-induced immune responses, which will help develop small-molecule drugs for coronavirus cure.
趋化因子由上皮细胞产生对于病毒感染时中性粒细胞招募到炎症部位至关重要。然而，趋化因子对上皮细胞的影响以及趋化因子如何参与冠状病毒感染仍有待充分理解。在这里，我们鉴定了一种可诱导的趋化因子白细胞介素-8（CXCL8/IL-8），它可以促进冠状病毒猪流行性腹泻病毒（PEDV）在非洲绿猴肾上皮细胞（Vero）和 Lilly Laboratories 细胞-猪肾 1 上皮细胞（LLC-PK1）中的感染。IL-8 的缺失限制了细胞质钙（Ca），而 IL-8 的刺激改善了细胞质 Ca。Ca 的消耗限制了 PEDV 的感染。当存在 Ca 螯合剂时，用 Ca 耗竭消除细胞质 Ca 时，PEDV 的内化和出芽明显减少。进一步的研究表明，上调的细胞质 Ca 重新分布细胞内 Ca。最后，我们鉴定出 G 蛋白偶联受体（GPCR）-磷脂酶 C（PLC）-肌醇三磷酸受体（IP3R）-储存操作 Ca（SOC）信号对于增强细胞质 Ca 和 PEDV 感染至关重要。据我们所知，这项研究首次揭示了趋化因子白细胞介素-8（IL-8）在冠状病毒 PEDV 感染上皮细胞中的作用。PEDV 诱导 IL-8 的表达以升高细胞质 Ca，从而促进其感染。我们的研究结果揭示了 IL-8 在 PEDV 感染中的新作用，并表明靶向 IL-8 可能是控制 PEDV 感染的一种新方法。 猪流行性腹泻冠状病毒（PEDV）是一种高度传染性的肠冠状病毒，在全球范围内造成了严重的经济损失，因此需要更多的努力来开发经济高效的疫苗来控制或消除这种疾病。趋化因子白细胞介素-8（CXCL8/IL-8）对于炎症介质的激活和运输以及肿瘤的进展和转移是不可或缺的。本研究评估了 IL-8 对上皮细胞中 PEDV 感染的影响。我们发现，IL-8 的表达改善了上皮细胞中的细胞质 Ca，促进了 PEDV 的快速内化和出芽。IL-8 通过 G 蛋白偶联受体（GPCR）-磷脂酶 C（PLC）-肌醇三磷酸受体（IP3R）-SOC 信号激活，从内质网（ER）释放细胞内 Ca 库。这些发现更好地理解了 IL-8 在 PEDV 诱导的免疫反应中的作用，这将有助于开发用于冠状病毒治疗的小分子药物。
