Is Required for Intracellular Replication of in Various Human Cells and Affects Its Polyamine Metabolism and Global Transcriptomes.

The gene has been reported to regulate polyamine metabolism in and , but its role in remains unknown. Our preliminary studies have revealed that widely affects the transcriptomes of infected M and Caco-2 cells and that it is required for the intracellular replication of serovar Typhimurium (. Typhimurium) in HeLa cells. In this study, we demonstrated that plays a time-dependent and cell type-independent role in the intracellular replication of . Typhimurium. Moreover, high-performance liquid chromatography (HPLC) of four major polyamines demonstrated putrescine, spermine, and cadaverine as the leading polyamines in . Typhimurium. The deletion of significantly increased the levels of the three polyamines in intracellular . Typhimurium, suggesting the inhibitory effect of on the biosynthesis of these polyamines. The deletion of was associated with elevated levels of these polyamines in the attenuated intracellular replication of . Typhimurium in host cells. This result was subsequently validated by the dose-dependent suppression of intracellular proliferation after the addition of the polyamines. Furthermore, our RNA transcriptome analysis of . Typhimurium SL1344 and its mutant outside and inside Caco-2 cells revealed that regulates the genes associated with flagellar biosynthesis, fimbrial expression, and functions of types III and I secretion systems. also affects the expression of genes that have been rarely reported to correlate with polyamine metabolism , including those associated with the periplasmic nitrate reductase system, glucarate metabolism, the phosphotransferase system, cytochromes, and the succinate reductase complex in . Typhimurium in the mid-log growth phase, as well as those in the - and histidine biosynthesis operons of intracellular . Typhimurium after invasion in Caco-2 cells. In the present study, we characterized the phenotypes and transcriptome effects of in . Typhimurium and reviewed the relevant literature to facilitate a more comprehensive understanding of the potential role of in the polyamine metabolism and virulence regulation of .