Brucella melitensis-infected HeLa cells gene expression

In a time course study, we characterized global gene expression profile of B. melitensis-infected epithelium-like cells at the onset of infection. B. melitensis-infected HeLa cells exhibited a down-regulated expression profile at 4 h (48 up- and 109 down-regulated genes) that transitioned to an activated transcriptional profile at 12 h post-infection (733 up- and 224 down-regulated genes). The analysis of the results indicates that infected cells undergo an adaptation period during the first 4 h p.i. that is overcome by 12 h p.i., permitting Brucella to replicate intracellularly while minimally affecting host physiological processes. Specific genes and biological processes identified in this study will further help elucidate how both host and Brucella interact during the early infectious process to the eventual benefit of the pathogen and to the detriment of the naïve host. Keywords: Time course study of gene expression profile of Brucella melitensis-infected HeLa cells We generated 4 different samples: A) RNA isolated from Brucella melitensis-infected HeLa cells at 4 h p.i.; B) RNA isolated from non-infected HeLa cells at 4 h p.i. of the A samples; C) RNA isolated from Brucella melitensis-infected HeLa cells at 12 h p.i., and D) RNA isolated from non-infected HeLa cells at 12 h p.i. of the D samples. The B. melitensis-infected HeLa cells gene expression was compared with gene expression from non-infected HeLa cells treated similarly. There are four biological replicates of each sample and time point (n=16). ORFs were single spotted on each microarray. Each replicate was normalized against labeled universal human reference RNA.

本研究通过时间进程实验，对感染马耳他布鲁氏菌（Brucella melitensis）的上皮样细胞在感染初期的全局基因表达谱进行了系统表征。感染马耳他布鲁氏菌的海拉（HeLa）细胞在感染后4 h p.i.呈现下调型表达谱（共48个基因上调、109个基因下调），并在感染后12 h p.i.转变为激活型转录谱（733个基因上调、224个基因下调）。结果分析表明，受感染细胞在感染后最初4 h p.i.处于适应性阶段，该状态在感染后12 h p.i.被打破，使得布鲁氏菌能够在细胞内增殖，同时对宿主生理过程的影响极小。本研究中鉴定得到的特定基因与生物学过程，将有助于进一步阐明宿主与布鲁氏菌在感染早期的互作机制，最终实现病原体的增殖优势，并使初始未感染宿主受到损害。关键词：马耳他布鲁氏菌感染海拉细胞的基因表达谱时间进程研究。本研究共设置4组独立样本：A）感染后4 h p.i.的马耳他布鲁氏菌感染海拉细胞的总RNA提取物；B）对应A样本、感染后4 h p.i.的未感染海拉细胞的总RNA提取物；C）感染后12 h p.i.的马耳他布鲁氏菌感染海拉细胞的总RNA提取物；D）取自标注为“of the D samples”的感染后12 h p.i.的未感染海拉细胞的总RNA提取物（原文疑似存在笔误）。将感染马耳他布鲁氏菌的海拉细胞的基因表达谱，与经过相同处理的未感染海拉细胞的基因表达谱进行对照分析。每组样本与每个时间点均设置4次生物学重复，总样本量为n=16。每个微阵列上均单点印刷开放阅读框（Open Reading Frames, ORFs）。每一次生物学重复样本均以标记后的通用人类参考RNA进行标准化处理。