Helicobacter pylori small RNA HPnc1470 represses HP0499/PldA/CGAT expression and modulates gastric epithelial morphology and inflammation

Abstract

Helicobacter pylori persistently colonizes the stomach and contributes to gastric inflammation and carcinogenesis via sustained interactions with gastric epithelial cells. Although bacterial small RNAs (sRNAs) are crucial post-transcriptional regulators, their roles in regulating H. pylori factors that influence host cell responses remain poorly understood. In this study, we characterized HPnc1470, an H. pylori sRNA of unknown function, and identified HP0499/PldA/CGAT, a lipid-modifying factor implicated in H. pylori-epithelial cell interactions, as a gene negatively regulated by HPnc1470. RNA-seq analysis revealed that hpnc1470 deletion increased HP0499 mRNA expression, and RT-qPCR confirmed this upregulation. HPnc1470 restoration reduced HP0499 mRNA expression to near wild-type levels, supporting negative regulation by HPnc1470. Furthermore, RNA-RNA interaction prediction and an electrophoretic mobility shift assay (EMSA) indicated that HPnc1470 binds the HP0499 5' regulatory region near the ribosome-binding site. In AGS cell infection assays, HPnc1470 loss enhanced H. pylori-induced elongation of AGS gastric epithelial cells and increased IL-8 production, whereas HP0499 deletion decreased both responses. These findings identify HPnc1470 as a negative regulator of HP0499 and suggest that sRNA-mediated regulation of HP0499 modulates gastric epithelial responses during H. pylori infection.