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Microbiology: Current Research 2017
Volume 1 Issue 2 Microbes Infection 2017
Notes:
Page 29
September 28-29, 2017 | London, UK
Microbes Infection
38th Annual congress on
The secret weapon that allows Staphylococcus
aureus to hijack your cell cycle
Nadejda Berkova
INRA, France
Statement of the Problem: Bacterial cyclomodulins are a
growing family of microbial virulence factors that not only
alter host cell cycle progression, but that also interfere with
host cell activity, thus favoring the hijacking of host cell
protective functions for their own benefit. Staphylococcus
aureus (S. aureus), a highly versatile Gram-positive pathogen
can cause life-threatening infections. The implication of S.
aureus in the alteration of the eukaryotic cell cycle and the
biological significance of such an alteration has not been fully
investigated.
Aim: The purpose of the study is to explore the mechanism
and to identify staphylococcal compounds that caused host
cell cycle arrest and to evaluate the benefit provided by
cyclomodulins to bacteria.
Methodology & Theoretical Orientation: Flow Cytometry
analysis, size exclusion chromatography, mass spectroscopy
analysis, Western blotting and immunofluorescence methods
were used to identify staphylococcal cyclomodulins and
characterize the mechanism.
Findings: We demonstrated that S. aureus-induced G2/M
transition delay was associated with the accumulation of
inactive cyclin-dependent kinase Cdk1, a key inducer of
mitosis entry, andwith the accumulation of unphosphorylated
histone H3. Phenol-soluble modulin a (PSMa) peptides
were found responsible for this effect. The use of S. aureus
mutants confirmed the findings. We showed that the G2
phase was preferential for bacterial proliferation and found
that PSMa-induced G2/M transition delay correlated with a
decrease in the defensins genes expression. We demonstrated
that additionally to secreted staphylococcal cyclomodulins
the membrane-anchored lipoprotein-like proteins exert
cyclomodulin activity.
Conclusion & Significance: Our findings demonstrate
that an alteration of the eukaryotic cell cycle enhances an
infective efficiency of bacterial pathogens, suggesting that
such an alteration may be used by S. aureus for propagation
within the host. Moreover, the correlation of PSMa-induced
G2/M transition delay with a decrease in the defensins genes
expression suggests a reduction of antibacterial functions of
infected cells.
Biography
Nadejda Berkova has her expertise in host-pathogen interaction. Her research
interest focuses on the molecular understanding of immunological pathways
and analysis of gene expression in the context of immune deregulation of the
organism. She investigates the mechanistic strategies of pathogens to subvert
the host defense for their own benefit. Her team identified several staphylococcal
cyclomodulins, the family of bacterial effectors that induce eukaryotic cell cycle
alterations, and demonstrated the involvement of these bacterial compounds in
the alteration of the host immune response. These findings are important for the
development of new anti-infective and anti-inflammatory strategies.
Nadejda Berkova, Microbiology: Current Research 2017