Inhibition of competence development, horizontal gene transfer and virulence in Streptococcus pneumoniae by a modified competence stimulating peptide.-猫眼课题宝

DOI：

10.1371/journal.ppat.1002241

发表时间：

2011-09

期刊：

PLoS pathogens

影响因子：

6.7

通讯作者：

中科院分区：

医学1区

文献类型：

作者：

Zhu L;Lau GW

来源链接：

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164649/?report=classic

Competence stimulating peptide (CSP) is a 17-amino acid peptide pheromone secreted by Streptococcus pneumoniae. Upon binding of CSP to its membrane-associated receptor kinase ComD, a cascade of signaling events is initiated, leading to activation of the competence regulon by the response regulator ComE. Genes encoding proteins that are involved in DNA uptake and transformation, as well as virulence, are upregulated. Previous studies have shown that disruption of key components in the competence regulon inhibits DNA transformation and attenuates virulence. Thus, synthetic analogues that competitively inhibit CSPs may serve as attractive drugs to control pneumococcal infection and to reduce horizontal gene transfer during infection. We performed amino acid substitutions on conserved amino acid residues of CSP1 in an effort to disable DNA transformation and to attenuate the virulence of S. pneumoniae. One of the mutated peptides, CSP1-E1A, inhibited development of competence in DNA transformation by outcompeting CSP1 in time and concentration-dependent manners. CSP1-E1A reduced the expression of pneumococcal virulence factors choline binding protein D (CbpD) and autolysin A (LytA) in vitro, and significantly reduced mouse mortality after lung infection. Furthermore, CSP1-E1A attenuated the acquisition of an antibiotic resistance gene and a capsule gene in vivo. Finally, we demonstrated that the strategy of using a peptide inhibitor is applicable to other CSP subtype, including CSP2. CSP1-E1A and CSP2-E1A were able to cross inhibit the induction of competence and DNA transformation in pneumococcal strains with incompatible ComD subtypes. These results demonstrate the applicability of generating competitive analogues of CSPs as drugs to control horizontal transfer of antibiotic resistance and virulence genes, and to attenuate virulence during infection by S. pneumoniae. Streptococcus pneumoniae is a major cause of pneumonia, ear infection and meningitis. Antibiotic resistance among S. pneumoniae isolates is increasingly a major clinical problem. The acquisition of antibiotic resistance genes in S. pneumoniae is controlled by a peptide pheromone called competence-stimulating peptide (CSP). CSP binds to a receptor called ComD, which in turn activates its cognate transcription factor ComE to initiate DNA uptake and integration into the S. pneumoniae genome. CSP-ComD/E also regulates the expression of virulence factors required for infection. In this study, multiple synthetic analogues of CSP pheromone were examined for their ability to inhibit acquisition of exogenous DNA, and to control infection by S. pneumoniae in mice. Two of these analogues, CSP1-E1A and CSP2-E1A, competitively inhibit the ability of S. pneumoniae to acquire the streptomycin resistance rpsL gene and the capsule gene cap3A during mouse models of acute pneumonia and bacteremia. CSP1-E1A also reduces mouse mortality during lung infection by S. pneumoniae. This is the first demonstration of the use of CSP analogues to attenuate virulence and to inhibit acquisition of an antibiotic resistance gene in S. pneumoniae. Because the CSP-ComD/E system is conserved among many pathogenic bacteria, CSP analogues may be applicable to reduce the spread of antibiotic resistance genes and to treat infections.