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Inflammatory tendencies and overproduction of IL-17 in the colon of young NOD mice are counteracted with diet change.

Alam C, Valkonen S, Palagani V, Jalava J, Eerola E, Hänninen A - Diabetes (2010)

Bottom Line: Young NOD mice showed a disturbed tolerance to autologous commensal bacteria.Increased numbers of activated CD4 T-cells and (CD11b(+)CD11c(+)) dendritic cells and elevated levels of Th17 cells and IL23 mRNA were moreover observed in colon lamina propria.Disrupted immune tolerance in the distal intestine may influence peritoneal cell pools and B-cell-mediated activation of diabetogenic T-cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland.

ABSTRACT

Objective: Dietary factors influence diabetes development in the NOD mouse. Diet affects the composition of microbiota in the distal intestine, which may subsequently influence intestinal immune homeostasis. However, the specific effects of antidiabetogenic diets on gut immunity and the explicit associations between intestinal immune disruption and type 1 diabetes onset remain unclear.

Research design and methods: Gut microbiota of NOD mice fed a conventional diet or ProSobee formula were compared using gas chromatography. Colonic lamina propria immune cells were characterized in terms of activation markers, cytokine mRNA and Th17 and Foxp3(+) T-cell numbers, using real-time PCR and flow cytometry. Activation of diabetogenic CD4 T-cells by purified B-cells was assessed in both groups. Immune tolerance to autologous commensal bacteria was evaluated in vitro using thymidine-incorporation tests.

Results: Young NOD mice showed a disturbed tolerance to autologous commensal bacteria. Increased numbers of activated CD4 T-cells and (CD11b(+)CD11c(+)) dendritic cells and elevated levels of Th17 cells and IL23 mRNA were moreover observed in colon lamina propria. These phenomena were abolished when mice were fed an antidiabetogenic diet. The antidiabetogenic diet also altered the expression levels of costimulatory molecules and the capacity of peritoneal B-cells to induce insulin-specific CD4 T-cell proliferation.

Conclusions: Young NOD mice show signs of subclinical colitis, but the symptoms are alleviated by a diet change to an antidiabetogenic diet. Disrupted immune tolerance in the distal intestine may influence peritoneal cell pools and B-cell-mediated activation of diabetogenic T-cells.

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Peritoneal B-cells' activation markers and antigen-presenting cell (APC) efficiency. A: Mean fluorescence intensity (MFI) of CD40 on peritoneal B1-cells from NOD (black bar) or PNOD (white bar). B: MFI of CD86 on peritoneal B1 cells from NOD (black bar) and PNOD (white bar). Data represent means ± SEM. ***P < 0.001, Student t test. n = 3–5 per group. C–F: Antigen-presenting cell capacity of peritoneal B-cells from NOD and PNOD to 4 μmol/l insulin peptide (C, D) and 20 μg/ml intact insulin (E and F). The graphs show B-cell induced T-cell proliferation using purified NOD (C and E) or PNOD (D and F) peritoneal B-cells (black bars) or splenic B-cells (striped bars). White bars indicate control values (relative baseline proliferation of T-cells + B-cells in the absence of insulin/insulin peptide). Baseline counts per min ranged between 50 and 300 cpm. Data present mean values ± SEM. n = 3–4 per group. *P < 0.05, **P < 0.01 as calculated with one-way ANOVA and Dunnet post hoc test. Peritoneal cells were pooled for each experiment from four mice to yield sufficient numbers of purified B-cells. Splenic B-cells were pooled and purified from the same donors.
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Figure 6: Peritoneal B-cells' activation markers and antigen-presenting cell (APC) efficiency. A: Mean fluorescence intensity (MFI) of CD40 on peritoneal B1-cells from NOD (black bar) or PNOD (white bar). B: MFI of CD86 on peritoneal B1 cells from NOD (black bar) and PNOD (white bar). Data represent means ± SEM. ***P < 0.001, Student t test. n = 3–5 per group. C–F: Antigen-presenting cell capacity of peritoneal B-cells from NOD and PNOD to 4 μmol/l insulin peptide (C, D) and 20 μg/ml intact insulin (E and F). The graphs show B-cell induced T-cell proliferation using purified NOD (C and E) or PNOD (D and F) peritoneal B-cells (black bars) or splenic B-cells (striped bars). White bars indicate control values (relative baseline proliferation of T-cells + B-cells in the absence of insulin/insulin peptide). Baseline counts per min ranged between 50 and 300 cpm. Data present mean values ± SEM. n = 3–4 per group. *P < 0.05, **P < 0.01 as calculated with one-way ANOVA and Dunnet post hoc test. Peritoneal cells were pooled for each experiment from four mice to yield sufficient numbers of purified B-cells. Splenic B-cells were pooled and purified from the same donors.

Mentions: NOD peritoneal B1 cells express abnormally high levels of CD40 and CD86, are more effective than splenic B-cells at presenting antigen to diabetogenic T-cells, and migrate at an enhanced rate to the pancreatic lymph nodes (29). The expression of costimulatory molecules CD40 and CD80 is significantly decreased on PNOD peritoneal B1-cells compared with NOD B1-cells (Fig. 6A and B). Peritoneal and splenic B-cells from NOD and PNOD were next tested in parallel for their antigen-presenting efficiency in presenting insulin or insulin peptide (insulin B9-23) to insulin B9-23 primed NOD CD4 T-cells (Fig. 6C–F). In contrast to NOD mice, peritoneal B-cells from PNOD mice were less efficient than splenic B-cells at presenting antigen (Fig. 6D and F). It is suggested that the decreased expression of CD40 and CD86 and the lessened antigen-presenting capacity in PNOD peritoneal cells is a consequence of lower activation status in the peritoneum, which in turn is a result of the lower inflammation level in the colon of PNOD mice.


Inflammatory tendencies and overproduction of IL-17 in the colon of young NOD mice are counteracted with diet change.

Alam C, Valkonen S, Palagani V, Jalava J, Eerola E, Hänninen A - Diabetes (2010)

Peritoneal B-cells' activation markers and antigen-presenting cell (APC) efficiency. A: Mean fluorescence intensity (MFI) of CD40 on peritoneal B1-cells from NOD (black bar) or PNOD (white bar). B: MFI of CD86 on peritoneal B1 cells from NOD (black bar) and PNOD (white bar). Data represent means ± SEM. ***P < 0.001, Student t test. n = 3–5 per group. C–F: Antigen-presenting cell capacity of peritoneal B-cells from NOD and PNOD to 4 μmol/l insulin peptide (C, D) and 20 μg/ml intact insulin (E and F). The graphs show B-cell induced T-cell proliferation using purified NOD (C and E) or PNOD (D and F) peritoneal B-cells (black bars) or splenic B-cells (striped bars). White bars indicate control values (relative baseline proliferation of T-cells + B-cells in the absence of insulin/insulin peptide). Baseline counts per min ranged between 50 and 300 cpm. Data present mean values ± SEM. n = 3–4 per group. *P < 0.05, **P < 0.01 as calculated with one-way ANOVA and Dunnet post hoc test. Peritoneal cells were pooled for each experiment from four mice to yield sufficient numbers of purified B-cells. Splenic B-cells were pooled and purified from the same donors.
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Related In: Results  -  Collection

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Figure 6: Peritoneal B-cells' activation markers and antigen-presenting cell (APC) efficiency. A: Mean fluorescence intensity (MFI) of CD40 on peritoneal B1-cells from NOD (black bar) or PNOD (white bar). B: MFI of CD86 on peritoneal B1 cells from NOD (black bar) and PNOD (white bar). Data represent means ± SEM. ***P < 0.001, Student t test. n = 3–5 per group. C–F: Antigen-presenting cell capacity of peritoneal B-cells from NOD and PNOD to 4 μmol/l insulin peptide (C, D) and 20 μg/ml intact insulin (E and F). The graphs show B-cell induced T-cell proliferation using purified NOD (C and E) or PNOD (D and F) peritoneal B-cells (black bars) or splenic B-cells (striped bars). White bars indicate control values (relative baseline proliferation of T-cells + B-cells in the absence of insulin/insulin peptide). Baseline counts per min ranged between 50 and 300 cpm. Data present mean values ± SEM. n = 3–4 per group. *P < 0.05, **P < 0.01 as calculated with one-way ANOVA and Dunnet post hoc test. Peritoneal cells were pooled for each experiment from four mice to yield sufficient numbers of purified B-cells. Splenic B-cells were pooled and purified from the same donors.
Mentions: NOD peritoneal B1 cells express abnormally high levels of CD40 and CD86, are more effective than splenic B-cells at presenting antigen to diabetogenic T-cells, and migrate at an enhanced rate to the pancreatic lymph nodes (29). The expression of costimulatory molecules CD40 and CD80 is significantly decreased on PNOD peritoneal B1-cells compared with NOD B1-cells (Fig. 6A and B). Peritoneal and splenic B-cells from NOD and PNOD were next tested in parallel for their antigen-presenting efficiency in presenting insulin or insulin peptide (insulin B9-23) to insulin B9-23 primed NOD CD4 T-cells (Fig. 6C–F). In contrast to NOD mice, peritoneal B-cells from PNOD mice were less efficient than splenic B-cells at presenting antigen (Fig. 6D and F). It is suggested that the decreased expression of CD40 and CD86 and the lessened antigen-presenting capacity in PNOD peritoneal cells is a consequence of lower activation status in the peritoneum, which in turn is a result of the lower inflammation level in the colon of PNOD mice.

Bottom Line: Young NOD mice showed a disturbed tolerance to autologous commensal bacteria.Increased numbers of activated CD4 T-cells and (CD11b(+)CD11c(+)) dendritic cells and elevated levels of Th17 cells and IL23 mRNA were moreover observed in colon lamina propria.Disrupted immune tolerance in the distal intestine may influence peritoneal cell pools and B-cell-mediated activation of diabetogenic T-cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland.

ABSTRACT

Objective: Dietary factors influence diabetes development in the NOD mouse. Diet affects the composition of microbiota in the distal intestine, which may subsequently influence intestinal immune homeostasis. However, the specific effects of antidiabetogenic diets on gut immunity and the explicit associations between intestinal immune disruption and type 1 diabetes onset remain unclear.

Research design and methods: Gut microbiota of NOD mice fed a conventional diet or ProSobee formula were compared using gas chromatography. Colonic lamina propria immune cells were characterized in terms of activation markers, cytokine mRNA and Th17 and Foxp3(+) T-cell numbers, using real-time PCR and flow cytometry. Activation of diabetogenic CD4 T-cells by purified B-cells was assessed in both groups. Immune tolerance to autologous commensal bacteria was evaluated in vitro using thymidine-incorporation tests.

Results: Young NOD mice showed a disturbed tolerance to autologous commensal bacteria. Increased numbers of activated CD4 T-cells and (CD11b(+)CD11c(+)) dendritic cells and elevated levels of Th17 cells and IL23 mRNA were moreover observed in colon lamina propria. These phenomena were abolished when mice were fed an antidiabetogenic diet. The antidiabetogenic diet also altered the expression levels of costimulatory molecules and the capacity of peritoneal B-cells to induce insulin-specific CD4 T-cell proliferation.

Conclusions: Young NOD mice show signs of subclinical colitis, but the symptoms are alleviated by a diet change to an antidiabetogenic diet. Disrupted immune tolerance in the distal intestine may influence peritoneal cell pools and B-cell-mediated activation of diabetogenic T-cells.

Show MeSH
Related in: MedlinePlus