Proteomic analysis of Hfq-regulon in B. pertussis

ALVAREZ HAYES, JIMENA; SURMANN KRISTIN; LAMBERTI, YANINA; BLANCÁ, BRUNO; RUIZ, ESPERANZA; VECEREK, BRADISLAV ; SCHMIDT FRANK; VOLKER UWE; RODRIGUEZ, MARÍA EUGENIA

Simposio; 12th International Symposium on Bordetella; 2019

Regulation of gene expression based on small non-coding RNA (sRNA) is a mechanism that enables bacterial rapid response to changes in the environmental conditions. Most of Gram-negative bacteria sRNA-mediated regulation requires the cofactor RNA-binding protein Hfq. Previous transcriptomic studies showed that Bordetella pertussis Hfq is involved in the regulation of expression of a wide number of genes. However, since Hfq acts at post-transcriptional level the changes observed at transcriptomic level may not necessarily correlate with alterations in protein profiles. In the present study, we used gel-free nanoLC-MS/MS-based proteomics to analyze and compare the protein profiles of B. pertussis wild type and its isogenic hfq defective deletion mutant (Δhfq) strains. We found that the absence of Hfq induced changes in the abundance of 302 (out of 1084) proteins. Among them, we identified proteins involved in cell wall biogenesis, stress response and virulence, all of them potentially relevant in host-pathogen interaction, suggesting that Hfq shapes B. pertussis pathogenesis. We further investigated the role of Hfq in B. pertussis adaptation to iron starvation, a stress condition that bacteria face inside host. To that end wild type and Δhfq strains were grown under iron-replete and iron depleted conditions and both iron-starved proteomes were compared... We found a significant role of this post-transcriptional regulator in this process. Importantly, the abundance of several bacterial virulence factors whose abundance changed in response to iron limitation was found to be dependent on Hfq. Altogether, these results indicate that Hfq regulates a significant portion of B. pertussis proteome (8% of total B. pertussis coding sequences) including bacterial factors implicated in host colonization.