Affiliation:
1. Department of Pulmonary and Critical Care Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Institute of Respiratory Disease of Sun Yat-Sen University, Guangzhou, People's Republic of China
2. School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
Abstract
ABSTRACT
The emergence of high-virulent
Acinetobacter baumannii
strains increases the mortality of patients and seriously affects their prognosis, which motivates us to explore novel ways to control such infections. In this study, gas chromatography–mass spectrometry was adopted to explore the metabolic difference between high- and low-virulent
A. baumannii
strains, and the decreased L-serine levels were identified as the most crucial biomarker in low-virulent
A. baumannii
strains.
In vitro
, L-serine reduced the virulence of
A. baumannii
to Beas 2B cells and inhibited the activation of NLRP3 inflammasome via decreasing the generation of ROS and mtROS and the release of inflammatory cytokines (IL-18 and IL-1β) through upregulating SIRT1.
In vivo
, the
Galleria mellonella
model was adopted. L-serine downregulated the levels of virulence genes (
ompA
,
carO
, and
omp
33-36), reduced the mortality of
A. baumannii
to
G. mellonella
, and decreased the blacking speed as well as the degree of
G. mellonella
after infection. Taken together, we found that L-serine can reduce the virulence of
A. baumannii
and enhance the host’s defense against the pathogen, providing a novel strategy for the treatment of infections caused by
A. baumannii
.
IMPORTANCE
Acinetobacter baumannii
has become one of the most common and severe opportunistic pathogens in hospitals. The high-virulent
A. baumannii
strains pose a great threat to patients and increase the risk of nosocomial infection. However, the mechanism of virulence in
A. baumannii
is still not well understood. In the present study, we identified potential biomarkers in low-virulent
A. baumannii
strains. Our analysis revealed the effect of L-serine on reducing the virulence of
A.baumannii
. This discovery suggests that targeting L-serine could be a promising strategy for the treatment or adjunctive treatment of
A. baumannii
infections. The development of treatments targeting virulence may provide a substitute for the increasingly failed traditional antibacterial treatment.
Funder
MOST | National Natural Science Foundation of China
GDSTC | Basic and Applied Basic Research Foundation of Guangdong Province
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Cell Biology,Microbiology (medical),Genetics,General Immunology and Microbiology,Ecology,Physiology