Proteomic analysis of intracellular Bordetella pertussis: Moving towards a better understanding of bacterial persistence and pathogenesis

SURMANN, KRISTIN; LAMBERTI, YANINA; CAFIERO, HILARIO; VALDEZ, HUGO; VECEREK, BRANISLAV; HOLUBOVA, JANA; SCHMIDT, FRANK; VÖLKER, UWE; RODRIGUEZ, M.EUGENIA

Congreso; Proteomic Forum 2019; 2019

QuestionSeveral studies indicated that Bordetella pertussis, the etiological agent of whooping cough, may have an intracellular phase during infection which might contribute to its persistence. Recently we have shown that upon entry into macrophages, B. pertussis survives in mildly acidic compartments. In order to elucidate its adaptation to the intracellular environment, we have analysed the proteome of B. pertussis upon internalization. MethodsThe human monocytic cell line THP-1 was infected with B. pertussis Tohama I at a multiplicity of infection of 150 bacteria per host cell. After 2 h incubation, the infection medium was replaced with fresh medium containing 100 μg/ml polymyxin B sulfate to kill the remaining extracellular bacteria. The proteome of B. pertussis isolated from host cells by sucrose density gradient centrifugation was examined by nanoLC-MS/MS 3 h and 48 h post infection and compared to extracellular B. pertussis grown in the same medium under similar conditions. Selected proteins were confirmed by single reaction monitoring.ResultsAlmost 300 out of 762 identified proteins showed altered levels in intracellular B. pertussis in comparison to non-internalized bacteria. These included proteins involved in stress response, iron uptake, cellular metabolism, transcriptional regulation, and virulence (Lamberti et al., J Proteomics, 2016). Among the proteins produced by the intracellular bacteria we identified BP0414 displaying homology to MgtC, a protein known to be involved in the intracellular survival of other pathogens. A follow-up study then revealed that MgtC might play a central role the adaptation of B. pertussis to the mildly acidic conditions found inside phagosomes (Cafiero et al., PLoS One, 2018). ConclusionTo our knowledge, we present the first analysis of the B. pertussis proteome upon macrophage infection and thus, provide new hints for understanding the intracellular adaptation and pathogenesis of B. pertussis.