Sodium absorption stimulator prostasin (PRSS8) has an anti-inflammatory effect via downregulation of TLR4 signaling in inflammatory bowel disease.

BACKGROUND:Prostasin (PRSS8) is a stimulator of epithelial sodium transport. In this study, we evaluated alteration of prostasin expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD) and investigated the role of prostasin in the gut inflammation.METHODS:Prostasin expression was evaluated by immunohistochemical staining. Dextran sodium sulfate (DSS)-colitis was induced in mice lacking prostasin specifically in intestinal epithelial cells (PRSS8ΔIEC mice).RESULTS:In colonic mucosa of healthy individuals, prostasin was strongly expressed at the apical surfaces of epithelial cells, and this was markedly decreased in active mucosa of both ulcerative colitis and Crohn\u27s disease. DSS-colitis was exacerbated in PRSS8ΔIEC mice compared to control PRSS8lox/lox mice. Toll-like receptor4 (TLR4) expression in colonic epithelial cells was stronger in DSS-treated PRSS8ΔIEC mice than in DSS-treated PRSS8 lox/lox mice. NF-κB activation in colonic epithelial cells was more pronounced in DSS-treated PRSS8ΔIEC mice than in DSS-treated PRSS8lox/lox mice, and the mRNA expression of inflammatory cytokines was significantly higher in DSS-treated PRSS8ΔIEC mice. Broad-spectrum antibiotic treatment completely suppressed the exacerbation of DSS-colitis in PRSS8ΔIEC mice. The mRNA expression of tight junction proteins and mucosal permeability assessed using FITC-dextran were comparable between DSS-treated PRSS8lox/lox and DSS-treated PRSS8ΔIEC mice.CONCLUSION:Prostasin has an anti-inflammatory effect via downregulation of TLR4 expression in colonic epithelial cells. Reduced prostasin expression in IBD mucosa is linked to the deterioration of local anti-inflammatory activity and may contribute to the persistence of mucosal inflammation

Nanoparticle curcumin ameliorates experimental colitis via modulation of gut microbiota and induction of regulatory T cells.

Curcumin is a hydrophobic polyphenol derived from turmeric, a traditional Indian spice. Curcumin exhibits various biological functions, but its clinical application is limited due to its poor absorbability after oral administration. A newly developed nanoparticle curcumin shows improved absorbability in vivo. In this study, we examined the effects of nanoparticle curcumin (named Theracurmin) on experimental colitis in mice.BALB/c mice were fed with 3% dextran sulfate sodium (DSS) in water. Mucosal cytokine expression and lymphocyte subpopulation were analyzed by real-time PCR and flow cytometry, respectively. The profile of the gut microbiota was analyzed by real-time PCR.Treatment with nanoparticle curcumin significantly attenuated body weight loss, disease activity index, histological colitis score and significantly improved mucosal permeability. Immunoblot analysis showed that NF-κB activation in colonic epithelial cells was significantly suppressed by treatment with nanoparticle curcumin. Mucosal mRNA expression of inflammatory mediators was significantly suppressed by treatment with nanoparticle curcumin. Treatment with nanoparticle curcumin increased the abundance of butyrate-producing bacteria and fecal butyrate level. This was accompanied by increased expansion of CD4+ Foxp3+ regulatory T cells and CD103+ CD8α- regulatory dendritic cells in the colonic mucosa.Treatment with nanoparticle curcumin suppressed the development of DSS-induced colitis potentially via modulation of gut microbial structure. These responses were associated with induction of mucosal immune cells with regulatory properties. Nanoparticle curcumin is one of the promising candidates as a therapeutic option for the treatment of IBD

Effect of nanoparticle curcumin on the fecal short-chain fatty acid (SCFA) levels.

<p>The concentrations of fecal SCFAs were measured by high-performance liquid chromatography. The data were expressed as means ± SEM (n = 6 mice/group). Values not sharing a letter are significantly different (<i>P</i><0.05).</p

Histological evaluation of colitis.

<p>(A) Histological picture of the colonic tissue on day 18. (original magnification ×200.) (B) Histological sore. The data are expressed as means ± SEM (n = 6 mice/group). (C) Epithelial permeability. Mice were orally administrated with FITC-labeled dextran (44 mg/100 g body weight), (MW 4000; FD4, Sigma-Aldrich Co.). Serum was collected 5 h later and fluorescence intensity was determined. Values not sharing a letter are significantly different (<i>P</i><0.05).</p

The effect of nanoparticle curcumin on NF-κB activation.

<p>(A) Immunoblot for NF-κBp65 in the nuclear protein of colonic epithelium. Lamin A/C was used as a loading control. The picture is representative of four independent experiments. (B) Immunohistochemical staining for NF-κBp65 in the tissues. (original magnification ×200). NF-κBp65 was detected in the nucleus of the epithelial cells in the DSS group, but this was completely blocked in the DSS plus nanoparticle curcumin group. (C) Immunostaining of NF-κBp65 in HT-29 cells. HT-29 cells were stimulated with TNF-α (100ng/ml) in the presence or absence of nanoparticle curcumin (10μM) for 15 minutes. NF-κB p65, green fluorescence; nucleus, DAPI (blue). (D) The effect of nanoparticle curcumin on IκBα phosphorylation in response to TNF-α. HT-29 cells were stimulated with TNF-α (100 ng/ml) in the presence or absence of nanoparticle curcumin (0μM, 10μM, or 50μM) for 15 minutes, and then lysed with lysis buffer. Lysates were subjected to immunoblot analysis. GAPDH were used as loading control. The data represent four independent experiments.</p

The effect of nanoparticle curcumin on the gut microbial structure.

<p>(A) T-RFLP analysis of the gut microbiota. The value indicates the percentage of the predicted bacteria. (B) Real-time PCR analysis for <i>Clostridium</i> cluster IV. (C) Real-time PCR analysis for <i>Clostridium</i> subcluster XIVa. The values were normalized to the amount of total bacteria, and presented as relative amount to the control group. The data were expressed as means ± SEM (n = 4 mice/group). Values not sharing a letter are significantly different (<i>P</i><0.05).</p

The effects of nanoparticle curcumin on the induction of Tregs and regulatory DCs in the lamina propria of the colon.

<p>(A) Flow cytometry analysis for CD4⁺ Foxp3⁺ Tregs in the lamina propria of the colon. Representative picture from two independent experiments. (B) Proportion of CD4⁺ Foxp3⁺ Treg cells in CD4⁺ cells in the lamina propria. The data are expressed as means ± SEM (n = 6 mice/group). Values not sharing a letter are significantly different (<i>P</i><0.05). (C) Flow cytometry analysis for CD103⁺ CD8α⁻ DCs in the lamina propria of the colon. Representative picture from two independent experiments. (D) Proportion of CD103⁺ CD8α⁻ DCs in CD11c⁺ cells in the lamina propria. The data are expressed as means ± SEM (n = 6 mice/group). Values not sharing a letter are significantly different (<i>P</i><0.05).</p

Effects of nanoparticle curcumin on fecal microbial composition.

<p>Effects of nanoparticle curcumin on fecal microbial composition.</p

Effect of nanoparticle curcumin on the development of DSS colitis.

<p>BALB/cAJcl mice were treated with nanoparticle curcumin (Theracurmin) for 7 days prior to the start of 3% DSS treatment. The mice were sacrificed on day 18. (A) Body weight. (B) Disease activity index. (C) Representative photographs of the colon. (D) Colonic weight/length on day 18. The data are expressed as means ± SEM (n = 6 mice/group). The data are representative of four independent experiments. Values not sharing a letter are significantly different (<i>P</i><0.05).</p