Table 1.
DSS-induced colitis experimental groups.
Table 2.
Scoring of DAI (modified according to Cooper et al. 1993).
Fig 1.
Phenotypic characteristics of F. prausnitzii strain HTF-F and A2-165.
a) Growth and biofilm formation of F. prausnitzii strains HTF-F and A2-165 in YCFAG medium under anaerobic conditions. i and ii) F. prausnitzii A2-165 before and after shaking respectively; iii and iv) F. prausnitzii HTF-F before and after shaking respectively. b) Gram staining of F. prausnitzii A2-165 (left panel) and HTF-F (right panel).
Fig 2.
Detection of F. prausnitzii HTF-F EPM by transmission electron microscopy.
F. prausnitzii HTF-F (a) possess a diffuse and irregular surface layer (arrow) which is thinner but similar to the capsule polysaccharide (CPS) of S. suis wild type strain (arrow, S. suis wt, left panel b) and absent in S. suis CPS deletion mutant (S. suis Δcps, right panel b).
Fig 3.
Cytokine secretion and surface marker expression in hDCs.
Cytokine secretion and surface marker expression in hDCs after 48 h of incubation with F. prausnitzii A2-165 (3 donors), F. prausnitzii HTF-F (3 donors), L. plantarum (5 donors), L. plantarum + EPM (5 donors), EPM (3 donors) or left unstimulated (5 donors). a) IL-10 and IL-12p70 were measured in the supernatant of hDCs. Error bars represent SEM, * indicates p<0.05 compared with L. plantarum treated samples. b) Percentage of CD83+ (left panel) and CD86+ (right panel) hDCs. Error bars represent SEM, ** indicates p<0.01, n.s. indicates non-significant compared with the control.
Fig 4.
Relative gene expression levels in hDCs determined by quantitative RT-PCR.
RNA was extracted from hDCs after 6 and 20 h of incubation with L. plantarum (in black), L. plantarum + EPM (in dark grey), EPM (in clear grey) or from unstimulated cells (in white) and the expression levels of IL-12p70 gene was calculated relative to the expression levels of the housekeeping gene GAPDH. Error bars represent SEM, n = 3, *** indicates p<0.001 compared with L. plantarum treated samples.
Fig 5.
Cytokine secretion in mouse BMDCs with and without anti-TLR2 blocking antibody.
a) IL-10 and IL-12p70 were measured in BMDC supernatants after incubation with L. plantarum, L. plantarum + EPM, EPM and unstimulated DCs. b) IL-10 and IL-12p70 were measured after incubation of BMDCs with the same samples as in panel (a) except that anti-TLR2 blocking antibody (anti-TLR2 Ab, dark grey bars) or an isotype control (isotype Ab, clear grey bars) were included during the incubation period. Error bars represent SEM (n = 3), *** indicates p<0.001, * indicates p<0.01, n.s. non-significant compared to L. plantarum treated samples.
Fig 6.
Clinical symptoms of DSS-colitis.
Disease activity index (DAI), colon histological damage score and clinical evaluation of DSS treated mice. Mice were left untreated (in white) or treated with DSS during 8 days and administered intrarectally with PBS (in black), EPM (in blue) or F. prausnitzii strains HTF-F (in red) or strain A2-165 (in green). DAI, histological score and colon length (a, b and c respectively) were evaluated at the end of the experiment. Mice body weight (d) was measured throughout the experiment, body weight values are expressed as percentage of the initial value measured at day 0 before DSS administration. Error bars represent SEM, n = 10, * indicates p<0.05, ** p<0.01, *** p<0.001 compared with the control colitis mice that received DSS + PBS.
Fig 7.
Histological colonic sections of DSS-treated mice.
Histological cross-sectional views of colon descendens of untreated or DSS-treated mice: a) colitis control, PBS-DSS-treated mice (damage grade 3–3.5) b) HTF-F-DSS-treated mice (damage grade 1–2.4); c) A2-165-DSS-treated mice, (damage grade 2–3.7); d) EPM-DSS-treated mice (damage grade 2.8–3.8); e) untreated mice (damage grade 0).
Fig 8.
Foxp3 expression in mesenteric lymph nodes and spleen of DSS-treated mice.
Percentage of Foxp3+ CD4+ T cells isolated from mesenteric lymph nodes (MLNs, left panel) and spleens (right panel) of mice untreated (in white) or treated with DSS during 8 days and administered intrarectally with PBS (in black), EPM (in blue) or F. prausnitzii strains HTF-F or strain A2-165 (HTF-F in red and A2-165 in green, respectively).
Fig 9.
IFN-γ and IL-17 secretion in colon cultures from DSS-treated mice.
Mice were left untreated or treated with DSS during 8 days and administered intrarectally with PBS, EPM or F. prausnitzii strains HTF-F or A2-165. Cytokines were measured in the supernatants of 48h cultures of colonic fragments isolated from mice. Error bars represent SEM, n = 5, * indicates p<0.05, ** p<0.01.