Contribution of sortase SrtA2 to Lactobacillus casei BL23 inhibition of Staphylococcus aureus internalization into bovine mammary epithelial cells.
Probiotics have been considered as a promising strategy to prevent various diseases in both humans and animals. This approach has gained interest in recent years as a potential means to control bovine mastitis. In a previous study, we found that several L. casei strains, including BL23, were able to inhibit the internalization of S. aureus, a major etiologic agent of mastitis, into bovine mammary epithelial cells (bMEC). This antagonism required a direct contact between L. casei and bMEC or S. aureus, suggesting the inhibition relied on interactions between L. casei cell surface components and bMEC. In this study, we have investigated the impact of some candidates which likely influence bacteria host cell interactions. We have shown that L. casei BL23 fbpA retained its inhibitory potential, indicating that L. casei BL23 antagonism did not rely (solely) on competition between S. aureus and L. casei fibronectin-binding proteins for adhesion to bMEC. We have then investigated the impact of four sortase mutants, srtA1, srtA2, srtC1 and srtC2, and a double mutant (srtA1-srtA2) on L. casei BL23 inhibitory potential. Sortases are responsible for the anchoring on the bacterial cell wall of LPXTG-proteins, which reportedly play an important role in bacteria-host cell interaction. All the srt mutants tested presented a reduced inhibition capacity, the most pronounced effect being observed with the srtA2 mutant. A lower internalization capacity of L. casei srtA2 into bMEC was also observed. This was associated with several changes at the surface of L. casei BL23 srtA2 compared to the wild type (wt) strain, including altered abundance of some LPXTG- and moonlighting proteins, and modifications of cell wall structure. These results strongly support the role of sortase A2 in L. casei BL23 inhibition against S. aureus internalization. Deciphering the contribution of the cell surface components altered in srtA2 strain in the inhibition will require further investigation.
INRA, UMR 1253 STLO, Rennes, France.|Agrocampus Ouest, UMR1253 STLO, Rennes, France.|Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.
Renata F S
RF
Souza
INRA, UMR 1253 STLO, Rennes, France.|Agrocampus Ouest, UMR1253 STLO, Rennes, France.
Julien
J
Jardin
INRA, UMR 1253 STLO, Rennes, France.|Agrocampus Ouest, UMR1253 STLO, Rennes, France.
Chantal
C
Cauty
INRA, UMR 1253 STLO, Rennes, France.|Agrocampus Ouest, UMR1253 STLO, Rennes, France.
Lucie
L
Rault
INRA, UMR 1253 STLO, Rennes, France.|Agrocampus Ouest, UMR1253 STLO, Rennes, France.
Damien S
DS
Bouchard
Micalis Institute, INRA, AgroParisTech, Paris-Saclay University, Jouy-en-Josas, France.
Luis G
LG
Bermúdez-Humarán
Micalis Institute, INRA, AgroParisTech, Paris-Saclay University, Jouy-en-Josas, France.
Philippe
P
Langella
Instituto de Agroquímica y Tecnología de Alimentos-CSIC, Paterna, Spain.
Vicente
V
Monedero
Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.
Núbia
N
Seyffert
Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.
Vasco
V
Azevedo
INRA, UMR 1253 STLO, Rennes, France.|Agrocampus Ouest, UMR1253 STLO, Rennes, France.
Yves
Y
Le Loir
INRA, UMR 1253 STLO, Rennes, France.|Agrocampus Ouest, UMR1253 STLO, Rennes, France.
Sergine
http://orcid.org/0000-0002-6836-2855
S
Even
D019881:Aminoacyltransferases / Q000235:genetics*; D000818:Animals; D001422:Bacterial Adhesion / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D001692:Biological Transport / Q000502:physiology; D002417:Cattle; D002473:Cell Wall / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000235:genetics*; D004847:Epithelial Cells / Q000187:drug effects / Q000382:microbiology*; D007780:Lacticaseibacillus casei / Q000502:physiology*; D008414:Mastitis, Bovine / Q000382:microbiology / Q000517:prevention & control* / Q000628:therapy; D008565:Membrane Proteins / Q000378:metabolism; D018384:Oxidative Stress; D033902:Periplasmic Binding Proteins / Q000378:metabolism; D019936:Probiotics / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000517:prevention & control; D013211:Staphylococcus aureus / Q000378:metabolism* / Q000472:pathogenicity
D001426:Bacterial Proteins; D008565:Membrane Proteins; D033902:Periplasmic Binding Proteins; D019881:Aminoacyltransferases; C120542:sortase A; D003546:Cysteine Endopeptidases