Bordetella pertussis infection affects iron homeostasis in macrophages

ALVAREZ HAYES, JIMENA; VALDEZ, HUGO; BLANCÁ, BRUNO; RODRIGUEZ, MARÍA EUGENIA

Mar del Plata, Buenos Aires, Argentina

Congreso; LXIV REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA; 2016

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. In the majority of Gram-negative bacteria, sRNA-mediated regulation requires Hfq, a cofactor RNA-binding protein, for proper gene regulation and stabilization. We previously showed that in Bordetella pertussis (Bp), the etiological agent of whooping cough, a significant portion of the genome is regulated in response to iron starvation, a condition that the bacteria faces inside the host, and that this phenotypic adaptation influences in the bacterial interaction with immune and epithelial host cells. In the present study we examined the requirement for Hfq in the adaptation of Bp to iron starvation. By mean of shotgun proteomics we compere the iron starved proteome of a Hfq mutant (∆Hfq-Bp-Fe) to iron starved proteome of wild type bacteria (Bp-Fe). We observed 125 proteins downregulated and 143 proteins upregulated in ∆Hfq-Bp-Fe as compared to Bp-Fe. Among them, we identified proteins involved in LPS and peptidoglycan biosynthesis, aminoacids metabolism and transport and transcriptional regulators, suggesting that Hfq plays a role on the regulation of diverse proteins during bacterial adaptation to iron starvation. Importantly, we observed that Hfq is involved in the regulation in response to low iron availability of iron acquisition systems and virulence factors, which are critical during infection. All together these results suggest that Hfq plays a role on regulation of diverse physiological processes during adaptation of B. pertussis to iron starvation which might impact in the infection of human host