Microsporidian EnP1 alters host cell H2B monoubiquitination and prevents ferroptosis facilitating microsporidia survival

Microsporidia are intracellular eukaryotic pathogens that pose a substantial threat to immunocompromised hosts. The way these pathogens manipulate host cells during infection remains poorly understood. Using a proximity biotinylation strategy we established that microsporidian EnP1 is a nucleus-targeted effector that modifies the host cell environment. EnP1's translocation to the host nucleus is meditated by nuclear localization signals (NLSs). In the nucleus, EnP1 interacts with host histone H2B. This interaction disrupts H2B monoubiquitination (H2Bub), subsequently impacting p53 expression. Crucially, this inhibition of p53 weakens its control over the downstream target gene SLC7A11, enhancing the host cell's resilience against ferroptosis during microsporidian infection. This favorable condition promotes the proliferation of microsporidia within the host cell. These findings shed light on the molecular mechanisms by which microsporidia modify their host cells to facilitate their survival. In order to investigate the impact of the overexpression of the microsporidian secreted protein EnP1 on host cell gene expression, we generated stable cell lines expressing EnP1 and GFP. We then utilized the RNA-seq data obtained from the stable cell lines expressing EnP1 and GFP for the analysis of gene expression profiles, with three biological replicates for each group.

微孢子虫（Microsporidia）是一类细胞内寄生的真核病原体，对免疫受损宿主构成严重威胁。目前学界对这类病原体在感染过程中操纵宿主细胞的具体机制仍知之甚少。本研究通过邻近生物素化（proximity biotinylation）策略证实，微孢子虫效应蛋白EnP1是一种定位于宿主细胞核的效应因子，可重塑宿主细胞微环境。EnP1的核转位过程由核定位信号（nuclear localization signals, NLSs）介导。在宿主细胞核内，EnP1可与宿主组蛋白H2B发生相互作用，该相互作用会干扰H2B单泛素化（H2B monoubiquitination, H2Bub）过程，进而影响p53的表达水平。至关重要的是，这种对p53的抑制作用会削弱其对下游靶基因SLC7A11的调控能力，从而增强宿主细胞在微孢子虫感染期间对抗铁死亡（ferroptosis）的耐受性。这一有利条件可促进微孢子虫在宿主细胞内的增殖。上述研究结果阐明了微孢子虫通过修饰宿主细胞以助力自身存活的分子机制。为探究微孢子虫分泌蛋白EnP1过表达对宿主细胞基因表达的影响，我们构建了分别稳定表达EnP1与绿色荧光蛋白（green fluorescent protein, GFP）的细胞系。随后，我们利用来源于这两类稳定细胞系的RNA测序（RNA-seq）数据开展基因表达谱分析，每组均设置三次生物学重复。