Time-Course Transcriptome Analysis of Lungs From Mice Infected With Hypervirulent Klebsiella pneumoniae via Aerosolize Intratracheal Inoculation

Purpose:Investigated transcriptome profile changes in the lungs of infected mice at different time points, to increase our understanding of hvKp pulmonary infection and to screen for genes or targets of research value. microarray and quantitative reverse transcription polymerase chain reaction (qRT–PCR) methods and to evaluate protocols for optimal high-throughput data analysis Methods: Animals were randomly divided into four infection groups and one control group (five mice per group), and the infected mice were euthanized at 12, 24, 48 and 60 h post-infection (hpi), respectively, while the control group mice were euthanized immediately after delivery of PBS at the 0 h time point. The lungs of the mice were isolated and divided into two parts for subsequent histopathologic examination or total RNA extraction. Results: Using the control group (0 hpi) as a reference, 6247 DEGs were identified across four time points after hvKp infection. At 12 hpi, 939 upregulated DEGs and 439 downregulated DEGs were detected, and by 60 hpi, 2647 upregulated DEGs and 2806 downregulated DEGs were detected. Overall, the number of upregulated and downregulated DEGs increased over time and a total of 688 genes were upregulated and 240 genes downregulated in common for all time points. And 12 of these were validated with qRT–PCR. RNA-seq data had a linear relationship with qRT–PCR for more than four orders of magnitude and a goodness of fit (R2) of 0.9548. To get a more holistic view, DEGs were clustered into nine clusters according to their temporal expression patterns.WGCNA was performed with the detected DEGs. The dynamic tree cutting algorithm in the WGCNA package was used to process the hierarchical clustering tree, and a total of 28 different modules were finally obtained. Conclusions: Our work both validates the results of previous studies on K. pneumoniae pulmonary infections and provides new additions and insights on hvKp pulmonary infections, which may contribute to the development of therapeutic approaches to reduce hvKp lung inflammation. Overall design: Lung mRNA profiles of c57 mice at 0, 12, 24, 48 and 60 hours after infection with hvKp