Department of Pediatrics.
Department of Biostatistics and Medical Informatics, and.
Am J Respir Cell Mol Biol. 2020 Jun;62(6):783-792. doi: 10.1165/rcmb.2019-0237OC.
Polymorphism at the 17q21 gene locus and wheezing responses to rhinovirus (RV) early in childhood conspire to increase the risk of developing asthma. However, the mechanisms mediating this gene-environment interaction remain unclear. In this study, we investigated the impact of one of the 17q21-encoded genes, (orosomucoid-like 3), on RV replication in human epithelial cells. knockdown inhibited RV-A16 replication in HeLa, BEAS-2B, A549, and NCI-H358 epithelial cell lines and primary nasal and bronchial epithelial cells. Inhibition varied by RV species, as both minor and major group RV-A subtypes RV-B52 and RV-C2 were inhibited but not RV-C15 or RV-C41. siRNA did not affect expression of the major group RV-A receptor ICAM-1 or initial internalization of RV-A16. The two major outcomes of ORMDL3 activity, SPT (serine palmitoyl-CoA transferase) inhibition and endoplasmic reticulum (ER) stress induction, were further examined: silencing decreased RV-induced ER stress and IFN-β mRNA expression. However, pharmacologic induction of ER stress and concomitant increased IFN-β inhibited RV-A16 replication. Conversely, blockade of ER stress with tauroursodeoxycholic acid augmented replication, pointing to an alternative mechanism for the effect of knockdown on RV replication. In comparison, the SPT inhibitor myriocin increased RV-A16 but not RV-C15 replication and negated the inhibitory effect of knockdown. Furthermore, lipidomics analysis revealed opposing regulation of specific sphingolipid species (downstream of SPT) by myriocin and siRNA, correlating with the effect of these treatments on RV replication. Together, these data revealed a requirement for ORMDL3 in supporting RV replication in epithelial cells via SPT inhibition.
17q21 基因座的多态性和儿童早期呼吸道合胞病毒 (RV) 引发的喘息反应共同增加了患哮喘的风险。然而，介导这种基因-环境相互作用的机制仍不清楚。在这项研究中，我们研究了 17q21 编码基因之一， (粘蛋白样蛋白 3)，对人上皮细胞中 RV 复制的影响。 基因敲低抑制了 HeLa、BEAS-2B、A549 和 NCI-H358 上皮细胞系以及原代鼻和支气管上皮细胞中的 RV-A16 复制。抑制作用因 RV 种类而异，因为小和大组 RV-A 亚型 RV-B52 和 RV-C2 受到抑制，但 RV-C15 或 RV-C41 不受抑制。 siRNA 不影响主要组 RV-A 受体 ICAM-1 的表达或 RV-A16 的初始内化。进一步研究了 ORMDL3 活性的两个主要结果，即 SPT（丝氨酸棕榈酰-CoA 转移酶）抑制和内质网 (ER) 应激诱导：沉默 降低了 RV 诱导的 ER 应激和 IFN-β mRNA 表达。然而，ER 应激的药理学诱导和随之而来的 IFN-β 增加抑制了 RV-A16 的复制。相反，用牛磺熊脱氧胆酸阻断 ER 应激增强了复制，这表明 基因敲低对 RV 复制的影响存在替代机制。相比之下，SPT 抑制剂霉菌酸增加了 RV-A16 但不增加 RV-C15 的复制，并否定了 基因敲低的抑制作用。此外，脂质组学分析显示，霉菌酸和 siRNA 对特定鞘脂种类（SPT 的下游）的调节相反，这与这些处理对 RV 复制的影响相关。总之，这些数据表明，ORMDL3 通过 SPT 抑制在支持上皮细胞中的 RV 复制方面是必需的。
