BP1092, a novel Bordetella pertussis virulence regulatory protein

MARTINA DEBANDI; MARIELA CARRICA; MASSON, CANDELA; YANTORNO, OSVALDO; RODRIGUEZ, MARIA EUGENIA.; LAMBERTI, YANINA

Simposio; First Virtual Bordetella Research Day; 2020

Transcription of B. pertussis virulence factors is controlled by the interrelated two-component systems BvgAS and RisAS. The participation of additional regulatory systems in this process is not clear. Here, we show an initial characterization of the protein BP1092, a histidine kinase probably belonging to a two-component system that was found overexpressed intracellularly in B. pertussis infecting macrophages (Lamberti et al, 2016). qRT-PCR assays showed that a B. pertussis BP1092 deficient strain (BPΔ1092) was unable to downregulate fha and bipA expression in bacteria growing under modulating conditions (SS medium containing 50 mM MgSO4), suggesting that this protein is involved in the regulation of virulence factors expression, affecting the transition to the avirulent phase. Accordingly, under modulating conditions BPΔ1092 but not the WT strain was able to form a biofilm, a way of lifestyle mainly dependent of FHA expression. It is interesting to note that homologues of BP1092 in B. bronchiseptica and B. parapertussis were found upregulated in bacteria growing under modulating conditions (data not published), supporting the involvement of this protein in the virulence modulation of Bordetella. Interestingly, the lack of expression of BP1092 resulted in a decreased survival of B. pertussis inside macrophages at early time post infection while neither bacterial attachment no phagocytosis were affected. This result suggest that early events of the intracellular survival depends on BP1092 possibly linked to the virulence of the intracellular phenotype This work reveals a new level of complexity of the virulence regulations of B. pertussis. Elucidating the role of BP1092 in the regulation Bordetella virulence might shed some light on the poorly understood pathogenesis of these bacteria.