Table_2_Campylobacter jejuni Demonstrates Conserved Proteomic and Transcriptomic Responses When Co-cultured With Human INT 407 and Caco-2 Epithelial Cells.XLSX

Major foodborne bacterial pathogens, such as Campylobacter jejuni, have devised complex strategies to establish and foster intestinal infections. For more than two decades, researchers have used immortalized cell lines derived from human intestinal tissue to dissect C. jejuni-host cell interactions. Known from these studies is that C. jejuni virulence is multifactorial, requiring a coordinated response to produce virulence factors that facilitate host cell interactions. This study was initiated to identify C. jejuni proteins that contribute to adaptation to the host cell environment and cellular invasion. We demonstrated that C. jejuni responds to INT 407 and Caco-2 cells in a similar fashion at the cellular and molecular levels. Active protein synthesis was found to be required for C. jejuni to maximally invade these host cells. Proteomic and transcriptomic approaches were then used to define the protein and gene expression profiles of C. jejuni co-cultured with cells. By focusing on those genes showing increased expression by C. jejuni when co-cultured with epithelial cells, we discovered that C. jejuni quickly adapts to co-culture with epithelial cells by synthesizing gene products that enable it to acquire specific amino acids for growth, scavenge for inorganic molecules including iron, resist reactive oxygen/nitrogen species, and promote host cell interactions. Based on these findings, we selected a subset of the genes involved in chemotaxis and the regulation of flagellar assembly and generated C. jejuni deletion mutants for phenotypic analysis. Binding and internalization assays revealed significant differences in the interaction of C. jejuni chemotaxis and flagellar regulatory mutants. The identification of genes involved in C. jejuni adaptation to culture with host cells provides new insights into the infection process.

空肠弯曲杆菌（Campylobacter jejuni）这类食源性细菌病原体，已演化出复杂策略以建立并维持肠道感染。二十余年来，研究者一直利用源自人类肠道组织的永生化细胞系，解析空肠弯曲杆菌与宿主细胞的互作机制。现有研究证实，空肠弯曲杆菌的致病过程具有多因子性，需要协同调控以产生促进宿主细胞互作的毒力因子。本研究旨在鉴定参与空肠弯曲杆菌适应宿主细胞环境以及细胞侵袭过程的蛋白质。本研究证实，空肠弯曲杆菌在细胞与分子层面对INT 407细胞与Caco-2细胞呈现相似的应答模式。研究发现，空肠弯曲杆菌要实现对这些宿主细胞的高效侵袭，需要活跃的蛋白质合成过程。随后，研究人员借助蛋白质组学与转录组学手段，明确了与宿主细胞共培养的空肠弯曲杆菌的蛋白质与基因表达谱。研究聚焦于共培养时空肠弯曲杆菌表达上调的基因，结果发现，空肠弯曲杆菌可通过合成特定基因产物快速适应与上皮细胞的共培养环境：这些基因产物可帮助其获取生长所需的特异性氨基酸、清除包括铁在内的无机分子、抵御活性氧/活性氮物质，并促进与宿主细胞的互作。基于上述发现，研究选取了参与趋化作用与鞭毛组装调控的部分基因，构建了空肠弯曲杆菌的缺失突变体以进行表型分析。结合与内化实验结果表明，空肠弯曲杆菌的趋化相关突变体与鞭毛调控相关突变体，其与宿主细胞的互作存在显著差异。本次研究鉴定出参与空肠弯曲杆菌适应宿主细胞共培养的基因，为阐明其感染过程提供了全新视角。