AvrA effector protein of Salmonella enterica serovar Enteritidis is expressed and translocated in mesenteric lymph nodes at late stages of infection in mice.
Salmonellosis is a major health problem worldwide. Salmonella enterica serovar Enteritidis (S. Enteritidis) has been a primary cause of Salmonella outbreaks in many countries. AvrA is an SPI-1 effector protein involved in the enteritis pathway, with critical roles in inhibiting inflammation and apoptosis. In this work, we constructed an AvrA-FLAG-tagged strain of S. Enteritidis to analyse the expression profile of AvrA in vitro, in cell culture and in vivo. AvrA expression and secretion were observed in vitro under culture conditions that mimicked intestinal and intracellular environments. In agreement, bacteria isolated from infected cell monolayers expressed and translocated AvrA for at least 24 h post-inoculation. For in vivo experiments, BALB/c mice were inoculated by the natural route of infection with the AvrA-FLAG strain. Infecting bacteria and infected cells were recovered from mesenteric lymph nodes (MLN). Our results showed that AvrA continues to be synthesized in vivo up to day 8 post-inoculation. Moreover, AvrA translocation was detected in the cytosol of cells isolated from MLN 8 days after infection. Interestingly, we observed that AvrA is secreted by both type three secretion system (T3SS)-1 and T3SS-2. In summary, these findings indicate that AvrA expression is not constrained to the initial host-bacteria encounter in the intestinal environment as defined previously. The AvrA effector may participate also in systemic S. Enteritidis infection.
Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM-CONICET) and Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
Mónica N
MN
Giacomodonato
Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM-CONICET) and Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
Mariángeles
M
Noto Llana
Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM-CONICET) and Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
María Del Rosario
MDR
Aya Castañeda
Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM-CONICET) and Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
Fernanda R
FR
Buzzola
Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM-CONICET) and Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
Sebastián H
SH
Sarnacki
Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM-CONICET) and Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
María C
MC
Cerquetti
D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D008198:Lymph Nodes / Q000382:microbiology*; D008807:Mice, Inbred BALB C; D021381:Protein Transport; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D012477:Salmonella enteritidis / Q000254:growth & development*; D013997:Time Factors
C495717:AvrA protein, Salmonella enterica; D001426:Bacterial Proteins