Proteomic analysis of Hfq-regulon in B. pertussis

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

Bruselas

Simposio; 12th International Symposium on Bordetella; 2019

International Bordetella Society

Regulation of gene expression by small non-coding RNA (sRNA) is a mechanism that enables bacteria to rapidly respond to changes in the environmental conditions. Most of the Gram-negative bacteria sRNA-mediated regulation requires the 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 deletion mutant (Δhfq). We found that the absence of Hfq induced changes in the abundance of 302 (out of 1084 detected) proteins. Among them, we identified proteins involved in cell wall biogenesis, stress response and virulence, all of them potentially relevant in host-pathogen interaction and thereby 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 the host. To that end, wild type and Δhfq strains were grown under iron-replete and iron depleted conditions and the different proteomes were compared. Our data indicate a significant role of this post-transcriptional regulator in this stress adaptation process. In particular , several bacterial virulence factors whose abundance changed in response to iron limitation were found to be dependent on Hfq. Collectively, these results indicate that Hfq affects the composition of a significant portion of B. pertussis proteome (8% of total B. pertussis coding sequences) including bacterial factors implicated in host colonization.