Water stable nanocoatings of poly(N-isopropylacrylamide)-based block copolymers on culture insert membranes for temperature-controlled cell adhesion.

This study demonstrated the spin-coating of functional diblock copolymers to develop smart culture inserts for thermoresponsive cell adhesion/detachment control. One part of the block components, the poly(n-butyl methacrylate) block, strongly supported the water stable surface-immobilization of the thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) block, regardless of temperature. The chain length of the PNIPAAm blocks was varied to regulate thermal surface functions. Immobilized PNIPAAm concentrations became larger with increasing chain length (1.0-1.6 µg cm-2) and the thicknesses of individual layers were relatively comparable at 10-odd nanometers. A nanothin coating scarcely inhibited the permeability of the original porous membrane. When human fibroblasts were cultured on each surface at 37 °C, the efficiencies of cell adhesion and proliferation decreased with longer PNIPAAm chains. Meanwhile, by reducing the temperature to 20 °C, longer PNIPAAm chains promoted cell detachment owing to the significant thermoresponsive alteration of cell-surface affinity. Consequently, we successfully produced a favorable cell sheet by choosing an appropriate PNIPAAm length for block copolymers.

Confounding effects of microbiome on the susceptibility of TNFSF15 to Crohn's disease in the Ryukyu Islands.

Crohn's disease (CD) involves chronic inflammation in the gastrointestinal tract due to dysregulation of the host immune response to the gut microbiome. Even though the host-microbiome interactions are likely contributors to the development of CD, a few studies have detected genetic variants that change bacterial compositions and increase CD risk. We focus on one of the well-replicated susceptible genes, tumor necrosis factor superfamily member 15 (TNFSF15), and apply statistical analyses for personal profiles of genotypes and salivary microbiota collected from CD cases and controls in the Ryukyu Islands, southernmost islands of the Japanese archipelago. Our association test confirmed the susceptibility of TNFSF15 in the Ryukyu Islands. We found that the recessive model was supported to fit the observed genotype frequency of risk alleles slightly better than the additive model, defining the genetic effect on CD if a pair of the chromosomes in an individual consists of all risk alleles. The combined analysis of haplotypes and salivary microbiome from a small set of samples showed a significant association of the genetic effect with the increase of Prevotella, which led to a significant increase of CD risk. However, the genetic effect on CD disappeared if the abundance of Prevotella was low, suggesting the genetic contribution to CD is conditionally independent given a fixed amount of Prevotella. Although our statistical power is limited due to the small sample size, these results support an idea that the genetic susceptibility of TNFSF15 to CD may be confounded, in part, by the increase of Prevotella.

Dysbiosis of salivary microbiota in inflammatory bowel disease and its association with oral immunological biomarkers.

Analysis of microbiota in various biological and environmental samples under a variety of conditions has recently become more practical due to remarkable advances in next-generation sequencing. Changes leading to specific biological states including some of the more complex diseases can now be characterized with relative ease. It is known that gut microbiota is involved in the pathogenesis of inflammatory bowel disease (IBD), mainly Crohn's disease and ulcerative colitis, exhibiting symptoms in the gastrointestinal tract. Recent studies also showed increased frequency of oral manifestations among IBD patients, indicating aberrations in the oral microbiota. Based on these observations, we analyzed the composition of salivary microbiota of 35 IBD patients by 454 pyrosequencing of the bacterial 16S rRNA gene and compared it with that of 24 healthy controls (HCs). The results showed that Bacteroidetes was significantly increased with a concurrent decrease in Proteobacteria in the salivary microbiota of IBD patients. The dominant genera, Streptococcus, Prevotella, Neisseria, Haemophilus, Veillonella, and Gemella, were found to largely contribute to dysbiosis (dysbacteriosis) observed in the salivary microbiota of IBD patients. Analysis of immunological biomarkers in the saliva of IBD patients showed elevated levels of many inflammatory cytokines and immunoglobulin A, and a lower lysozyme level. A strong correlation was shown between lysozyme and IL-1ß levels and the relative abundance of Streptococcus, Prevotella, Haemophilus and Veillonella. Our data demonstrate that dysbiosis of salivary microbiota is associated with inflammatory responses in IBD patients, suggesting that it is possibly linked to dysbiosis of their gut microbiota.

Fucoidan enhances intestinal barrier function by upregulating the expression of claudin-1.

AIM: To evaluate the protective effects of fucoidan on oxidative stress-induced barrier disruption in human intestinal epithelial cells. METHODS: In Caco-2 cell monolayer models, the disruption of barrier function by oxidative stress is mediated by H2O2. The integrity of polarized Caco-2 cell monolayers was determined by measuring the transepithelial resistance (TER) and permeability was estimated by measuring the paracellular transport of FITC-labeled 4-kDa dextran (FD4). The protective effects of fucoidan on epithelial barrier functions on polarized Caco-2 cell monolayers were evaluated by TER and FD4 flux. The expression of tight junction (TJ) proteins was assessed using reverse-transcription polymerase chain reaction (RT-PCR) and immunofluorescence staining. RESULTS: Without H2O2 treatment, fucoidan significantly increased the TER compared to control (P < 0.05), indicating a direct enhancement of intestinal epithelial barrier function. Next, H2O2 disrupted the epithelial barrier function in a time-dependent manner. Fucoidan prevented the H2O2-induced destruction in a dose-dependent manner. Fucoidan significantly decreased H2O2-induced FD4 flux (P < 0.01), indicating the prevention of disruption in paracellular permeability. RT-PCR showed that Caco-2 cells endogenously expressed claudin-1 and -2, and occludin and that H2O2 reduced the mRNA expression of these TJ proteins. Treatment with fucoidan attenuated the reduction in the expressions of claudin-1 and claudin-2 but not occludin. Immunofluorescence staining revealed that the expression of claudin-1 was intact and high on the cell surface. H2O2 disrupted the integrity of claudin-1. Treatment with fucoidan dramatically attenuated the expression of claudin-1. CONCLUSION: Fucoidan enhanced intestinal epithelial barrier function by upregulating the expression of claudin-1. Thus, fucoidan may be an appropriate therapy for the treatment of inflammatory bowel diseases.

Imbalance of NKp44(+)NKp46(-) and NKp44(-)NKp46(+) natural killer cells in the intestinal mucosa of patients with Crohn's disease.

BACKGROUND & AIMS: Mucosal natural killer (NK) cells that produce interleukin (IL)-22 mediate intestinal homeostasis and inflammation in mice. However, their role in the pathogenesis of human inflammatory bowel diseases (IBDs) is not known. We investigated intestinal NK cells in intestinal mucosa samples of patients with Crohn's disease (CD). METHODS: We isolated lamina propria NK cells from intestinal mucosal samples of patients with IBD and subjects without IBD (controls) and analyzed expression patterns of cell surface molecules and cytokine production. Interactions between lamina propria NK cells and intestinal macrophages were examined. RESULTS: In intestinal mucosa samples from controls, NKp44 and NKp46 were expressed differentially on CD3(-)CD56(+) NK cells, NKp44(+)NKp46(-) (NKp44(+)) NK cells expressed CD127 and the transcription factor retinoic acid-related orphan receptor C (RORC) and produced IL-22 whereas NKp44(-)NKp46(+) (NKp46(+)) NK cells did not express CD127 or RORC and produced interferon (IFN)-gamma. NKp46(+) NK cells were predominant in intestinal mucosa of patients with CD compared with controls or patients with ulcerative colitis. Upon interaction with intestinal inflammatory macrophages NKp46(+), NK cells from patients with CD were activated via IL-23 and produced IFN-gamma; this activation required cell-to-cell contact. CONCLUSIONS: The balance of NKp44(+)/NKp46(+) NK cells is disrupted in intestinal mucosa of patients with CD. NKp46(+) NK cells might mediate the pathogenesis of CD by producing IFN-gamma.

Monocyte chemoattractant protein-1 contributes to gut homeostasis and intestinal inflammation by composition of IL-10-producing regulatory macrophage subset.

Lamina propria macrophages (LPMs) spontaneously produce large amounts of anti-inflammatory IL-10 and play a central role in regulation of immune responses against commensal bacteria. MCP-1 is a chemokine that plays an important role in recruitment of monocytes and macrophages to inflamed tissues. We demonstrated that, in addition to IL-10, LPMs produced large amounts of MCP-1, even in a steady state. MCP-1 deficiency caused impaired IL-10 production by LPMs and led to exacerbation of dextran sulfate sodium-induced acute colitis. As an explanation of this impaired IL-10 production by LPMs, we found that LPMs could be separated into two subsets with distinct side-scattered properties, namely LPM1 (CD11b(+)F4/80(+)CD11c(-)SSC(hi)) and LPM2 (CD11b(+)F4/80(+)CD11c(-)SSC(lo)). Unlike LPM1, the LPM2 subset migrated in response to MCP-1 and produced a larger amount of IL-10 in response to commensal bacteria. LPMs isolated from MCP-1-deficient mice produced less IL-10 as a consequence of the lack of the MCP-1-dependent LPM2 population. This imbalanced composition in LPM population may be involved in the susceptibility to DSS-induced colitis in MCP-1-deficient mice. Our results suggest that endogenous MCP-1 contributes to the composition of resident LPM subsets in the intestine. Moreover, MCP-1-dependent LPM2 subset may play an important role in maintenance of gut homeostasis in the steady state, and in the termination of excess inflammatory responses in the intestine, by producing IL-10.

TL1A produced by lamina propria macrophages induces Th1 and Th17 immune responses in cooperation with IL-23 in patients with Crohn's disease.

BACKGROUND: Tumor necrosis factor (TNF)-like protein 1A (TL1A) is a member of the TNF superfamily and contributes to the pathogenesis of Crohn's disease (CD) by stimulating T-helper (Th) 1 cells. In addition to Th1, recent studies have focused on the role of Th17 cells in the pathogenesis of CD. Here we tried to clarify the role of TL1A in Th1 and Th17 immunity in CD. METHODS: TL1A expression was assessed by quantitative reverse-transcription polymerase chain reaction (RT-PCR) in lamina propria (LP) macrophages (LP-M phi s) from normal controls (NC) and patients with CD or ulcerative colitis (UC). Purified LP CD4(+) T cells were stimulated with TL1A and/or IL-23 and interferon gamma (IFN-gamma) and interleukin (IL)-17 levels were analyzed. We also examined the effect of TL1A on naïve CD4(+) T-cell differentiation. RESULTS: We found that LP-M phi s are a major producer of TL1A. TL1A expression was markedly enhanced in LP-M phi s from CD patients compared with NC or UC patients. IL-23, in addition to TL1A, was induced in LP-M phi s by commensal bacteria stimulation. TL1A and IL-23 synergistically promoted the production of IFN-gamma and IL-17 by LP T cells, while TL1A alone did not induce cytokine production. Furthermore, TL1A promoted Th17 differentiation from naïve T cells by LP-M phi s; however, IL-23 did not show any synergistic effects on Th17 differentiation. CONCLUSIONS: TL1A expressed in LP-M phi s might play an important role in the pathogenesis of CD by inducing Th1 and Th17 immunity. IL-23 differentially regulated these functions of TL1A on memory and naïve T cells.

Human CD14+ macrophages in intestinal lamina propria exhibit potent antigen-presenting ability.

Intestinal APCs are considered critical in maintaining the balance between the response against harmful pathogens and the induction of tolerance to commensal bacteria and food Ags. Recently, several studies indicated the presence of gut-specific APC subsets, which possess both macrophage and dendritic cell (DC) markers. These unique APC subsets play important roles in gut immunity, especially for immune regulation against commensal bacteria. Herein, we examined a unique macrophage subset, which coexpressed the macrophage (Mphi) marker CD14 and the DC marker CD209 in human intestinal lamina propria (LP). The LP Mphi subset in both normal control subjects or Crohn's disease (CD) patients induced proliferation of naive CD4(+) T cells as well as monocyte-derived DCs, and it expressed retinoic acid synthetic enzyme retinaldehyde dehydrogenase 2 and retinol dehydrogenase 10, which induced expression of gut homing receptors on T cells in a retinoic acid-dependent manner. Moreover, the LP Mphi subset strongly evoked differentiation of Th1 cells and slightly induced Th17 cells in both normal control subjects and CD patients; the inducing potential was highest in CD patients. In CD patients, Th17, but not Th1, induction by the LP Mphi subset was enhanced in the presence of commensal bacteria Ags. This enhancement was not observed in normal control subjects. The Th17 induction by the LP Mphi subset was inhibited by neutralization of IL-6 and IL-1beta, but it was enhanced by blockade of retinoic acid signaling. These observations highlight a role for LP Mphi in the enhanced Th1, and potentially in Th17 differentiation, at the inflammatory site of inflammatory bowel diseases.

Dietary histidine ameliorates murine colitis by inhibition of proinflammatory cytokine production from macrophages.

BACKGROUND & AIMS: Elemental diet (ED) is effective for human Crohn's disease (CD). Although some of this effectiveness may be due to its low antigenic load and low fat content, the mechanisms remain unclear. We sought to assess the role of histidine, one of the constituent amino acids of ED, in controlling colitis. METHODS: The interleukin (IL)-10-deficient (IL-10(-/-)) cell transfer model of colitis was used. SCID mice with colitis induced by transfer of IL-10(-/-) cells were maintained on experimented diets containing either single amino acids or a mixture. The severity of colitis was assessed by wet colon weight. Colonic tumor necrosis factor (TNF)-alpha messenger RNA (mRNA) expression was detected by quantitative reverse-transcription polymerase chain reaction. Mouse peritoneal macrophages were stimulated by lipopolysaccharides (LPS), with or without amino acids. The concentration of cytokines in the supernatant was determined by enzyme-linked immunosorbent assay. Inhibitor of nuclear factor (NF)-kappaB-alpha and nuclear p65 were confirmed by immunoblotting. RESULTS: In the IL-10(-/-) transfer model, dietary histidine, but not alanine, reduced histologic damage and colon weight and TNF-alpha mRNA expression. Histidine inhibited LPS-induced TNF-alpha and IL-6 production by mouse macrophages in a concentration-dependent manner, whereas alanine or histidine-related metabolites had no such effect. Histidine inhibited LPS-induced NF-kappaB in macrophages. CONCLUSIONS: These results showed that histidine could be a novel therapeutic agent for CD by inhibition of NF-kappaB activation, following down-regulation of proinflammatory cytokine production by macrophages. Thus, our studies provided new insights into the roles of amino acid metabolism in the pathophysiology of CD and for therapeutic strategies.

Tetomilast suppressed production of proinflammatory cytokines from human monocytes and ameliorated chronic colitis in IL-10-deficient mice.

BACKGROUND: Tetomilast (OPC-6535) was originally developed as a compound inhibiting superoxide production in neutrophils. Although its mechanism of action is not completely understood, phosphodiesterase type 4 inhibitory function has been postulated. The therapeutic effect of PDE4 inhibitors has been reported for chronic inflammatory disorders such as chronic obstructive pulmonary diseases. In this study we aimed to examine whether tetomilast could be a novel drug for inflammatory bowel diseases by further clarifying its antiinflammatory effects. METHODS: Cytokines from human peripheral blood mononuclear cells were measured by enzyme-linked immunosorbent assay (ELISA) and Cytokine Beads Array. The transcripts were quantified by reverse-transcriptase polymerase chain reaction (RT-PCR). Phosphorylation of transcription factors was examined by phosflow. To examine its in vivo effect, a once-daily oral dose of tetomilast was tested in murine IL-10(-/-) chronic colitis. RESULTS: Tetomilast suppressed TNF-alpha and IL-12 but not IL-10 production from lipopolysaccharide (LPS)-stimulated human monocytes. It suppressed TNF-alpha, IFN-gamma, and IL-10 from CD4 lymphocytes. Tetomilast suppressed cytokine production at the transcriptional level but did not alter phosphorylation of p65, ERK, p38, and STAT3. HT-89, a protein kinase A inhibitor, did not abolish the effect of tetomilast, suggesting that it was independent from the classical cAMP/PKA pathway. IL-10 was not essential to the inhibitory effect of tetomilast on TNF-alpha and IL-12. Tetomilast ameliorated IL-10(-/-) chronic colitis with reduced clinical symptoms, serum amyloid A, and histological scores with decreased TNF-alpha mRNA expression. CONCLUSIONS: Tetomilast exerts its antiinflammatory effects on human monocytes and CD4 cells. Combined with in vivo data these findings support the feasibility of tetomilast as a novel drug for inflammatory bowel diseases.

Unique CD14 intestinal macrophages contribute to the pathogenesis of Crohn disease via IL-23/IFN-gamma axis.

Intestinal macrophages play a central role in regulation of immune responses against commensal bacteria. In general, intestinal macrophages lack the expression of innate-immune receptor CD14 and do not produce proinflammatory cytokines against commensal bacteria. In this study, we identified what we believe to be a unique macrophage subset in human intestine. This subset expressed both macrophage (CD14, CD33, CD68) and DC markers (CD205, CD209) and produced larger amounts of proinflammatory cytokines, such as IL-23, TNF-alpha, and IL-6, than typical intestinal resident macrophages (CD14-CD33+ macrophages). In patients with Crohn disease (CD), the number of these CD14+ macrophages were significantly increased compared with normal control subjects. In addition to increased numbers of cells, these cells also produced larger amounts of IL-23 and TNF-alpha compared with those in normal controls or patients with ulcerative colitis. In addition, the CD14+ macrophages contributed to IFN-gamma production rather than IL-17 production by lamina propria mononuclear cells (LPMCs) dependent on IL-23 and TNF-alpha. Furthermore, the IFN-gamma produced by LPMCs triggered further abnormal macrophage differentiation with an IL-23-hyperproducing phenotype. Collectively, these data suggest that this IL-23/IFN-gamma-positive feedback loop induced by abnormal intestinal macrophages contributes to the pathogenesis of chronic intestinal inflammation in patients with CD.

Exacerbating role of gammadelta T cells in chronic colitis of T-cell receptor alpha mutant mice.

BACKGROUND & AIMS: T-cell receptor (TCR) gammadelta T cells are an important component of the mucosal immune system and regulate intestinal epithelial homeostasis. Interestingly, there is a significant increase in gammadelta T cells in the inflamed mucosa of patients with ulcerative colitis (UC). However, the role of gammadelta T cells in chronic colitis has not been fully identified. METHODS: TCRalpha-deficient mice, which spontaneously develop chronic colitis with many features of human UC including an increase in gammadelta T-cell population, represent an excellent model to investigate the role of gammadelta T cells in UC-like colitis. To identify the role of gammadelta T cells in this colitis, we herein have generated TCRgamma-deficient mice through deletion of all TCR Cgamma genes (Cgamma1, Cgamma2, Cgamma3, and Cgamma4) using the Cre/loxP site-specific recombination system and subsequently crossing these mice with TCRalpha-deficient mice. RESULTS: An increase in colonic gammadelta T cells was associated with the development of human UC as well as UC-like disease seen in TCRalpha-deficient mice. Interestingly, the newly established TCRalpha(-/-) x TCRgamma(-/-) double mutant mice developed significantly less severe colitis as compared with TCRalpha-deficient mice. The suppression of colitis in TCRalpha(-/-) x TCRgamma(-/-) double mutant mice was associated with a significant reduction of proinflammatory cytokine and chemokine productions and a decrease in neutrophil infiltration. CONCLUSIONS: gammadelta T cells are involved in the exacerbation of UC-like chronic disease. Therefore, gammadelta T cells may represent a promising therapeutic target for the treatment of human UC.