Lactobacillus crispatus M247-derived H2O2 acts as a signal transducing molecule activating peroxisome proliferator activated receptor-gamma in the intestinal mucosa.
OBJECTIVE
Accumulating evidence indicates that the peroxisome proliferator activated receptor (PPAR)-gamma is a major player in maintaining intestinal mucosa homeostasis, but whether PPAR-gamma is directly involved in probiotic-mediated effects and the molecular events involved in its activation are not known.


METHODS
We investigated the role of PPAR-gamma in the immunomodulatory effects of Lactobacillus crispatus M247 on intestinal epithelial cells (IEC) and the role of probiotic-derived H(2)O(2) on PPAR-gamma activity.


RESULTS
L crispatus M247 supplementation in mice significantly increased PPAR-gamma levels and transcriptional activity in the colonic mucosa. L crispatus M247 induced PPAR-gamma nuclear translocation and enhanced transcriptional activity in epithelial (CMT-93) cells, as demonstrated by the increased luciferase activity of a PPAR-gamma-responsive element, PPAR-gamma-responsive gene up-regulation, and reduced activity of an nuclear factor-kappaB-responsive element. Pharmacologic PPAR-gamma inhibition or silencing by small interfering RNA cancelled the L crispatus M247-mediated effects in CMT-93 cells. Because Lactobacillus strains producing little H(2)O(2) failed to activate PPAR-gamma, we investigated the role of L crispatus M247-derived H(2)O(2) in PPAR-gamma activation. L crispatus M247 induced a transient rise in intracellular H(2)O(2) and PPAR-gamma transcriptional activity was cancelled by antioxidant or H(2)O(2) scavenger. Toll-like receptor (TLR)-2 was not required for PPAR-gamma up-regulation mediated by L crispatus M247 in mice, although the protective effects of L crispatus M247 on dextran sodium sulfate-induced colitis were less pronounced in TLR-2(-/-) mice.


CONCLUSIONS
L crispatus M247 uses H(2)O(2) as a signal transducing molecule to induce PPAR-gamma activation in IEC, directly modulating epithelial cell responsiveness to inflammatory stimuli.
Voltan
Sandra
S
Department of Histology, Microbiology and Medical Biotechnologies, University of Padua, Italy.
Martines
Diego
D
Elli
Marina
M
Brun
Paola
P
Longo
Stefano
S
Porzionato
Andrea
A
Macchi
Veronica
V
D'Incà
Renata
R
Scarpa
Melania
M
Palù
Giorgio
G
Sturniolo
Giacomo C
GC
Morelli
Lorenzo
L
Castagliuolo
Ignazio
I
D000818:Animals; D002460:Cell Line; D003092:Colitis / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D003106:Colon / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D005609:Free Radicals / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007155:Immunologic Factors / Q000276:immunology / Q000378:metabolism; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D007778:Lactobacillus / Q000276:immunology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D047495:PPAR gamma / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D019936:Probiotics; D015398:Signal Transduction / Q000276:immunology*; D014158:Transcription, Genetic / Q000276:immunology; D014162:Transfection
D016207:Cytokines; D005609:Free Radicals; D007155:Immunologic Factors; D047495:PPAR gamma; D006861:Hydrogen Peroxide