Helicobacter pylori proteins response to nitric oxide stress.

Helicobacter pylori is a highly pathogenic microorganism with various strategies to evade human immune responses. Nitric oxide (NO) and reactive nitrogen species (RNS) generated via nitric oxide synthase pathway are important effectors during the innate immune response. However, the mechanisms of H. pylori to survive the nitrosative stress are not clear. Here the proteomic approach has been used to define the adaptive response of H. pylori to nitrosative stress. Proteomic analysis showed that 38 protein spots were regulated by NO donor, sodium nitroprusside (SNP). These proteins were involved in protein processing, anti-oxidation, general stress response, and virulence, as well as some unknown functions. Particularly, some of them were participated in iron metabolism, potentially under the control of ferric uptake regulator (Fur). Real time PCR revealed that fur was induced under nitrosative stress, consistent with our deduction. One stress-related protein up-regulated under nitrosative conditions was thioredoxin reductase (TrxR). Inactivation of fur or trxR can lead to increased susceptivity to nitrosative stress respectively. These studies described the adaptive response of H. pylori to nitric oxide stress, and analyzed the relevant role of Fur regulon and TrxR in nitrosative stress management.