Regulatory Mechanisms Of Iron Ions On Escherichia Coli Outer Membrane Protein OmpW

The innate immune response serves as the major immune system of hostdefense against pathogens, and the most effective strategy is to control the iron statusof body fluid. Furthermore, Iron plays a critical role in the pathogen pathogenicity andvirulence, virulence and pathogenicity depend on its capability of iron uptake fromthe host. However, the molecular mechanism of iron on pathogen virulence has notbeen elucidated. Recent studies have found that OmpW widespread in Gram-negativebacteria is a multifunctional protein. It is involved in a variety of antibiotics resistance,osmoregulation, osmotic stress and other diverse environments. Above all, it isassociated with pathogen virulence and pathogenicity, associated with a variety ofinfectious diseases. In addition，studies indicated that the expression of OmpW isrelated to iron, but the regulatory mechanism of iron on OmpW has not beenelucidated.First, in order to confirme whether the expression of OmpW is regulated by iron,we use Western blot to analysis of the OmpW expression with different iron ionsconcentration.It showed that the level of OmpW expression is upregulated by iron. inthis study, the recombinant expression vector pACYC184-ompW was constructed.Then the recombinant vector was transferred into ΔompW to obtain the ompWfunctional complemention. Meanwhile, taking advantage of FerroZine to analysecapacity of iron uptake in K12, ΔompW and+ompW. It suggested that the ΔompWuptaked more iron and however, K12and+ompW took on the reverse result. Itindicated that OmpW maybe play a role in iron ion transportion. Furthermore, inorder to verify which transcription factor is involved in regulating iron on the OmpWexpression, using Real-Time PCR to analyse the transcription factor expression innormal and iron limiting environments. With the iron limited, the levelof thetranscription factor Fur expression is downregulated, while the levelof SoxSexpression did not change. It revealed that Fur may participate regulating the OmpWby iron.Using the vector pET-28(+) to construct Fur, SoxS overexpression strains, and analysed the OmpW expression from overexpression bacteria by Real-Time PCR andWestern blot. It found that the OmpW was upregulated in the Fur overexpressionstrains, however, that the OmpW was downregulated in the SoxS overexpressionstrains. To sum up, the OmpW was upregulated by Fur, and the regulation of iron onthe OmpWwas mediated by the Fur.Those resulat revealed the mechanisms that iron can enhance the pathogenvirulence and pathogenicity, mechanisms of iron ions on Escherichiacoli outer membrane protein W (OmpW) in order to deeply comprehend theinteraction between infection and immunization, layed a foundation for furtherresearching about fully disclosing iron mediated pathogen virulence and pathogenicmechanism, provided new targets to e control and treat infectious diseases mediatedby iron.This research has important theoretical significance and application value.