TY - JOUR
T1 - Characterization of lipoteichoic acid structures from three probiotic Bacillus strains
T2 - involvement of d-alanine in their biological activity
AU - Villéger, Romain
AU - Saad, Naima
AU - Grenier, Karine
AU - Falourd, Xavier
AU - Foucat, Loïc
AU - Urdaci, Maria C.
AU - Bressollier, Philippe
AU - Ouk, Tan Sothea
N1 - Publisher Copyright:
© 2014, The Author(s).
PY - 2014/10/1
Y1 - 2014/10/1
N2 - Probiotics represent a potential strategy to influence the host’s immune system thereby modulating immune response. Lipoteichoic Acid (LTA) is a major immune-stimulating component of Gram-positive cell envelopes. This amphiphilic polymer, anchored in the cytoplasmic membrane by means of its glycolipid component, typically consists of a poly (glycerol-phosphate) chain with d-alanine and/or glycosyl substitutions. LTA is known to stimulate macrophages in vitro, leading to secretion of inflammatory mediators such as Nitric Oxide (NO). This study investigates the structure–activity relationship of purified LTA from three probiotic Bacillus strains (Bacillus cereus CH, Bacillus subtilis CU1 and Bacillus clausii O/C). LTAs were extracted from bacterial cultures and purified. Chemical modification by means of hydrolysis at pH 8.5 was performed to remove d-alanine. The molecular structure of native and modified LTAs was determined by 1H NMR and GC–MS, and their inflammatory potential investigated by measuring NO production by RAW 264.7 macrophages. Structural analysis revealed several differences between the newly characterized LTAs, mainly relating to their d-alanylation rates and poly (glycerol-phosphate) chain length. We observed induction of NO production by LTAs from B. subtilis and B. clausii, whereas weaker NO production was observed with B. cereus. LTA dealanylation abrogated NO production independently of the glycolipid component, suggesting that immunomodulatory potential depends on d-alanine substitutions. d-alanine may control the spatial configuration of LTAs and their recognition by cell receptors. Knowledge of molecular mechanisms behind the immunomodulatory abilities of probiotics is essential to optimize their use.
AB - Probiotics represent a potential strategy to influence the host’s immune system thereby modulating immune response. Lipoteichoic Acid (LTA) is a major immune-stimulating component of Gram-positive cell envelopes. This amphiphilic polymer, anchored in the cytoplasmic membrane by means of its glycolipid component, typically consists of a poly (glycerol-phosphate) chain with d-alanine and/or glycosyl substitutions. LTA is known to stimulate macrophages in vitro, leading to secretion of inflammatory mediators such as Nitric Oxide (NO). This study investigates the structure–activity relationship of purified LTA from three probiotic Bacillus strains (Bacillus cereus CH, Bacillus subtilis CU1 and Bacillus clausii O/C). LTAs were extracted from bacterial cultures and purified. Chemical modification by means of hydrolysis at pH 8.5 was performed to remove d-alanine. The molecular structure of native and modified LTAs was determined by 1H NMR and GC–MS, and their inflammatory potential investigated by measuring NO production by RAW 264.7 macrophages. Structural analysis revealed several differences between the newly characterized LTAs, mainly relating to their d-alanylation rates and poly (glycerol-phosphate) chain length. We observed induction of NO production by LTAs from B. subtilis and B. clausii, whereas weaker NO production was observed with B. cereus. LTA dealanylation abrogated NO production independently of the glycolipid component, suggesting that immunomodulatory potential depends on d-alanine substitutions. d-alanine may control the spatial configuration of LTAs and their recognition by cell receptors. Knowledge of molecular mechanisms behind the immunomodulatory abilities of probiotics is essential to optimize their use.
KW - Immunomodulation
KW - Lipoteichoic acid
KW - Probiotics
KW - Structure–activity relationship
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U2 - 10.1007/s10482-014-0239-8
DO - 10.1007/s10482-014-0239-8
M3 - Article
C2 - 25090957
AN - SCOPUS:84926174238
SN - 0003-6072
VL - 106
SP - 693
EP - 706
JO - Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology
JF - Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology
IS - 4
ER -