BP1092, A BORDETELLA PERTUSSIS VIRULENCE REGULATORY PROTEIN INVOLVED IN ADAPTATION TO INTRACELLULAR ENVIRONMENT

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

Congreso; Reunión Anual de Sociedades de Biociencias; 2020

Bordetella pertussis (Bp), which causes whooping cough, surviveswithin macrophages, and adapts its bacterial proteome during intracellular infection. Virulence factors play a key role in bacterial persistence inside the host cell. Transcription of Bp virulence factors arecontrolled by the interrelated two-component systems BvgAS andRisAS. The participation of additional regulatory systems in this process is not clear. The aim of this work was to characterize the contribution of the BP1092 protein, a two-component system histidinekinase overexpressed intracellularly, in virulence factor regulationand intracellular survival.To this end, we constructed a Bp deletion mutant defective inBP1092 (BPΔ1092) and analysed the differential expression ofvirulence factors representative of the virulent (fhaB), intermediate (bipA), and avirulent (vraA, kpsE) phases by qRT-PCR understandard (SS medium) and modulating conditions (SS medium + 50mM). We showed that BpΔ1092, unlike the parental strain (wt), wasunable to downregulate fha and bipA expression in bacteria growingunder modulating conditions, suggesting that this protein is involvedin the transition to the avirulent phase. Accordingly, by mean of microtiter crystal violet assay, we showed that under modulating conditions BpΔ1092, but not the WT strain, was able to form a biofilm, away of lifestyle mainly dependent of fhaB expression. Interestingly,microscopy and antibiotic protection assays, showed that the lack ofexpression of BP1092 resulted in a decreased survival of Bp insidemacrophages. This result suggests that early events of the intracellular survival depend on BP1092 expression. All the data presentedhere were statistically significant with p