INVESTIGADORES
MOLLERACH Marta Eugenia
congresos y reuniones científicas
Título:
Functional characterization of S. pneumoniae galU knockout strains: Could the enzyme UDPG:PP be a novel antimicrobial target?
Autor/es:
COOLS F; TORFS E; VANHUTTE B; CAPPOEN D,; BONOFIGLIO L; MOLLERACH M; COS P
Lugar:
Bruselas
Reunión:
Jornada; Microbiome and Host Metabolism, Meeting of National Committee for Microbiology National Committee for Biochemistry and Molecular Biology of The Royal Academies of Science and the Arts of Belgium; 2016
Institución organizadora:
Belgian Society for Biochemistry and Molecular Biology
Resumen:
Streptococcus pneumoniae has been recognized as one of the major bacterial agents of several infectious mucosal and invasive diseases, such as community acquired pneumonia, otitis media and meningitis. Despite available antibiotic treatments, there is a significant mortality from pneumococcal infections, with rates approaching 40% in susceptible hosts (WHO Publication, 2012). The most important virulence factor of S. pneumoniae is its polysaccharide capsule, which prevents opsonization by complement factors, adhesion and macrophage phagocytosis (GENO et al., 2015). The enzyme UTP-glucose-1-phosphate uridylyltransferase (UDPG:PP) is encoded by the galU gene and catalyzes the formation of uridine diphosphate glucose (UDPGlc) from glucose 1-phosphate (Glc-1P). UDP-Glc is the substrate for the synthesis of UDPglucuronic acid, and is also required for the interconversion of galactose and glucose by way of the Leloir pathway, making it a key component in the biosynthetic pathway of pneumococcal capsular polysaccharides (FREY, 1996, MOLLERACH et al., 1998). Also in other bacterialspecies UDPG:PP has a relevant role in virulence, since UDP-Glc is the main glucosyl donor in lipopolysaccharide and capsule biosynthesis. UDPG:PP is widely distributed among animals, plants and other microorganisms but the eukaryotic UDPG:PPs are evolutionary completely unrelated to their prokaryotic counterparts (FLORES-DIAZ et al., 1997). Therefore, UDPG:PP might be a valuable novel target in fighting bacterial diseases.In this study, several characteristics of 5 different pneumococcal galU knockout strains and their non-mutated parent strains were evaluated. Firstly, planktonic and biofilm growth was studied. There was no difference in planktonic growth between parent strains and their respective knockouts, but there were some significant differences in biofilm formation. Because adhesion is the first step towards biofilm formation and pathogenesis, the adhesion to A549 lung epithelial cells was tested. Also, adhesion to RAW246.7 macrophages and macrophage phagocytosis was studied. Our results show that there is an influence of the galU gene product, since deletion of the gene makes the bacteria more prone to phagocytosis and increases their adhesion to both epithelial cells and macrophages in most cases. These data give a first indication that UDPG:PP is involved in pathogenesis and thus might be a novel antimicrobial target, but more experiments are needed.ReferencesFLORES-DIAZ, M., ALAPE-GIRON, A., PERSSON, B., POLLESELLO, P., MOOS, M., VON EICHELSTREIBEL,C., THELESAM, M., FLORIN, I. (1997) J Biol Chem. 272:23784-23791.FREY, P.A. (1996) FASEB J. 10:461-470.GENO, K.A., GILBERT, G. L., SING, J. Y., SKOVSTED, I. C., KLUGMAN, K. P., JONES, C., KONRADSENH.B., NAHM, M. H. (2015) Clin Microbiol Rev. 28:871-899.MOLLERACH, M., LOPEZ, R., GARCIA, E. (1998) J Exp Med. 188:2047-2056.WHO PUBLICATION. (2012) Vaccine. 30:4717-4718.