干扰素-λ3 促进上皮防御和屏障功能抵抗微小隐孢子虫感染。
Interferon-λ3 Promotes Epithelial Defense and Barrier Function Against Cryptosporidium parvum Infection.
机构信息
Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina; Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.
Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina; Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.
出版信息
Cell Mol Gastroenterol Hepatol. 2019;8(1):1-20. doi: 10.1016/j.jcmgh.2019.02.007. Epub 2019 Mar 5.
BACKGROUND & AIMS: The epithelial response is critical for intestinal defense against Cryptosporidium, but is poorly understood. To uncover the host strategy for defense against Cryptosporidium, we examined the transcriptional response of intestinal epithelial cells (IECs) to C parvum in experimentally infected piglets by microarray. Up-regulated genes were dominated by targets of interferon (IFN) and IFN-λ3 was up-regulated significantly in infected piglet mucosa. Although IFN-λ has been described as a mediator of epithelial defense against viral pathogens, there is limited knowledge of any role against nonviral pathogens. Accordingly, the aim of the study was to determine the significance of IFN-λ3 to epithelial defense and barrier function during C parvum infection.
METHODS
The significance of C parvum-induced IFN-λ3 expression was determined using an immunoneutralization approach in neonatal C57BL/6 mice. The ability of the intestinal epithelium to up-regulate IFN-λ2/3 expression in response to C parvum infection and the influence of IFN-λ2/3 on epithelial defense against C parvum invasion, intracellular development, and loss of barrier function was examined using polarized monolayers of a nontransformed porcine-derived small intestinal epithelial cell line (IPEC-J2). Specifically, changes in barrier function were quantified by measurement of transepithelial electrical resistance and transepithelial flux studies.
RESULTS
Immunoneutralization of IFN-λ2/3 in C parvum-infected neonatal mice resulted in a significantly increased parasite burden, fecal shedding, and villus blunting with crypt hyperplasia during peak infection. In vitro, C parvum was sufficient to induce autonomous IFN-λ3 and interferon-stimulated gene 15 expression by IECs. Priming of IECs with recombinant human IFN-λ3 promoted cellular defense against C parvum infection and abrogated C parvum-induced loss of barrier function by decreasing paracellular permeability to sodium.
CONCLUSIONS
These studies identify IFN-λ3 as a key epithelial defense mechanism against C parvum infection.
背景与目的
上皮细胞反应对于肠道抵御隐孢子虫至关重要，但目前对此知之甚少。为了揭示宿主抵御隐孢子虫的策略，我们通过微阵列分析研究了实验感染仔猪的肠道上皮细胞（IECs）对 C parvum 的转录反应。上调的基因主要是干扰素（IFN）的靶标，IFN-λ3 在感染仔猪黏膜中显著上调。尽管 IFN-λ 已被描述为抵抗病毒病原体的上皮防御介质，但对非病毒病原体的任何作用知之甚少。因此，本研究的目的是确定 IFN-λ3 在 C parvum 感染期间对上皮防御和屏障功能的重要性。
方法
使用新生 C57BL/6 小鼠的免疫中和方法确定 C parvum 诱导的 IFN-λ3 表达的意义。使用非转化的猪源性小肠上皮细胞系（IPEC-J2）的极化单层研究了 C parvum 感染后肠道上皮细胞上调 IFN-λ2/3 表达的能力，以及 IFN-λ2/3 对上皮防御隐孢子虫入侵、细胞内发育和屏障功能丧失的影响。具体而言，通过测量跨上皮电阻和跨上皮通量研究来量化屏障功能的变化。
结果
在 C parvum 感染的新生小鼠中中和 IFN-λ2/3 导致寄生虫负担显著增加，粪便脱落，感染高峰期绒毛变钝，隐窝增生。在体外，C parvum 足以诱导 IEC 自主表达 IFN-λ3 和干扰素刺激基因 15。用重组人 IFN-λ3 对 IEC 进行预处理可促进细胞防御 C parvum 感染，并通过降低钠的旁通透性来阻止 C parvum 诱导的屏障功能丧失。
结论
这些研究将 IFN-λ3 确定为抵抗 C parvum 感染的关键上皮防御机制。
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