Hfq is required for Bordetella pertussis adaptation to the iron starved host environment

JIMENA ALVAREZ HAYES; YANINA LAMBERTI; BRUNO BLANCÁ; KRISTIN SURMANN; FRANK SCHMIDT; MARIA EUGENIA RODRIGUEZ

Buneos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedad Argentina de Inmunología

Bacterial regulation of gene expression based on small noncoding RNA (sRNA) is usually involved in the response to environmental stress, such as iron starvation. Most of Gram-negative bacteria sRNA-mediated regulation requires the cofactor RNA-binding protein Hfq. It was shown that Bordetella pertussis (Bp) is iron starved inside its human host in which is able to survive and eventually persist inside macrophages (MΦ). As strategy to study the infective phenotype, we previously characterized Bp iron-starved proteome and showed that this environmental condition induces a remarkable shift in protein composition. Importantly, we observed that this phenotypic adaptation influences bacterial interaction with immune and epithelial cells facilitating the infectious process. In the present study, we examined the requirement for Hfq in the adaptation of Bp to iron starvation in order to evaluate its relevance in bacterial pathogenesis. By mean of shotgun proteomics we compare the iron-starved proteome of a Bp Hfq deficient mutant (Bp∆Hfq) with the iron-starved proteome of the wild type strain and found that 375 (out of 1325) proteins required Hfq to respond to low iron availability. Among them, we identified proteins involved in LPS and peptidoglycan biosynthesis, metabolism and transport, suggesting that Hfq plays a role in the regulation of many different pathways during Bp adaptation to iron starvation. Importantly, we observed that under this environmental condition Hfq plays a role in the regulation of the expression of several proteins critical during infection, such as iron acquisition systems, proteins involved in oxidative stress resistance and virulence factors. Accordingly, intracellular survival of Bp∆Hfq inside THP-1 MΦ was significantly lower than wild type bacteria (p