Therapeutic effect of intracolonically administered nuclear factor kappa B (p65) antisense oligonucleotide on mouse dextran sulphate sodium (DSS)-induced colitis

Novel anti-inflammatory action of 5-aminoimidazole-4-carboxamide ribonucleoside with protective effect in dextran sulfate sodium-induced acute and chronic colitis

AMP-activated protein kinase (AMPK) is an important cellular energy sensor that is responsible for maintaining systemic and cellular energy balance. Its role in intestinal inflammation remains unclear. Recent studies indicate that AMPK activation initiated by 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) participates in modulating inflammatory responses. Inflammatory bowel disease (IBD) has been characterized by sustained intestinal mucosa inflammation, caused mainly by excessive macrophage activation and T helper type 1 (Th1) and Th17 immune responses. Thus, we sought to determine the effect of AICAR on inflammatory responses of murine models of IBD. Mice with acute or chronic colitis induced by dextran sulfate sodium (DSS) were treated with or without AICAR. Body weight and colon inflammation were evaluated, and production of proinflammatory cytokines in colon tissues was determined. Nuclear factor kappaB (NF-kappaB) activation in colon tissues was assayed, and Th1 and Th17 cell responses were also evaluated. By inducing AMPK activation, AICAR had a therapeutic effect in ameliorating acute and chronic DSS-induced murine colitis as shown by reduced body weight, loss and significant attenuation in clinical symptoms, and histological inflammation. Moreover, AICAR treatment inhibited NF-kappaB activation in macrophages, reduced levels of Th1- and Th17-type cytokines in colon tissues, and down-regulated Th1 and Th17 cell responses during the progress of acute and chronic experimental colitis. AICAR acts as a central inhibitor in immune responses of experimental colitis. Our data show that AICAR-initiated AMPK activation may represent a promising alternative to our current approaches to suppress intestinal inflammation in IBD.

Met-RANTES down-regulates the expression of MIP-3α and CCR6 in the colon of mice with experimental ulcerative colitis

AIM: To investigate the role of macrophage inflammatory protein-3α (MIP-3α) and chemokine receptor 6 (CCR6) in the pathogenesis of ulcerative colitis (UC) and to explore the mechanism of therapeutic effect of Met-RANTES against UC.

METHODS: Forty mice were randomly and equally divided into four groups: blank control group, model control group, normal saline group, and Met-RANTES treatment group. Ulcerative colitis was induced in mice by giving dextran sodium sulfate (DSS). The impact of Met-RANTES on disease activity index (DAI), gross morphological score (GMS) and histopathological score (HPS) in UC was then evaluated. The expression of MIP-3α and CCR6 mRNAs was measured by reverse transcription-polymerase chain reaction (RT-PCR). The expression of MIP-3α and CCR6 proteins was examined by Western blot and immunohistochemistry.

RESULTS: The DAI, GMS and HPS were higher in the model control group and the normal saline group than in the blank control group. The expression levels of MIP-3α and CCR6 mRNAs and proteins in UC were significantly higher in the model control group and the normal saline group than in the blank control group (all P < 0.01). The DAI, GMS and HPS as well as the expression levels of MIP-3α and CCR6 mRNAs and proteins in the Met-RANTES treatment group were significantly lower than those in the model control group and the normal saline group (mRNA: 0.21 ± 0.08 vs 1.09 ± 0.08 and 1.08 ± 0.07, and 0.25 ± 0.08 vs 1.11 ± 0.07 and 1.05 ± 0.08; protein: 0.28 ± 0.08 vs 0.98 ± 0.07 and 1.05 ± 0.06, and 0.25 ± 0.07 vs 1.19 ± 0.07 and 1.15 ± 0.06; all P < 0.01). In contrast, no statistical differences were noted in DAI, GMS and HPS as well as the expression levels of MIP-3α and CCR6 mRNAs and proteins between the model control group and the normal saline group (all P > 0.05).

CONCLUSION: The expression of MIP-3α and its receptor CCR6 is up-regulated in UC, which is closely related with the development and progression of UC. Met-RANTES can down-regulate the expression of MIP-3α and CCR6 and ameliorate inflammatory damage in mice with UC. MIP-3α and CCR6 may represent novel pharmacological targets for treatment of UC.

ROS, Hsp27, and IKKbeta mediate dextran sodium sulfate (DSS) activation of IkappaBa, NFkappaB, and IL-8

BACKGROUND

Dextran sodium sulfate (DSS) is a sulfated polysaccharide that has been very widely used to induce inflammation in experimental models of inflammatory bowel disease in which the effects of pharmacologic and biologic therapies are tested. However, the precise mechanisms by which DSS induces inflammation have not been elucidated.

METHODS

DSS-induced increases in phospho-IkappaBalpha, nuclear NFkappaB (p65), and IL-8 secretion in human colonic epithelial cells in tissue culture are attributable to a reactive oxygen species (ROS)-induced pathway of inflammation, and do not require TLR4, MyD88, or Bcl10, which are associated with the innate immune pathway of NFkappaB-IL-8 activation.

RESULTS

DSS-induced increases were inhibited by the ROS scavengers Tempol and Tiron, were associated with decreased phosphorylation of MAPK12 (p38gamma), MAPK 13 (p38delta), and Hsp27, and required the IkappaB kinase (IKK) signalosome component IKKbeta. In ex vivo colonic tissue from TLR4-deficient mice, or following knockdown of MyD88 or Bcl10 or exposure to an IRAK 1/4 inhibitor, DSS effects were not suppressed. Data demonstrated that DSS activates IkappaBalpha, NFkappaB, and IL-8 through an ROS-Hsp27-IKKbeta-mediated pathway, and not through an innate immune cascade.

CONCLUSIONS

These results suggest that DSS models of inflammation may not be optimal for evaluation of interventions that involve mechanisms of innate immunity.

Chemopreventive effects of the standardized extract (DA-9601) of Artemisia asiatica on azoxymethane-initiated and dextran sulfate sodium-promoted mouse colon carcinogenesis

Dextran sulfate sodium (DSS) administration has been reported to cause inflammation in mouse colonic mucosa, which promotes colon carcinogenesis. When male ICR mice were treated with a single intraperitoneal dose (10 mg/kg body weight) of azoxymethane (AOM) followed by 2.5% DSS in drinking water for 7 consecutive days, all developed tumors at the 16th wk, mostly in the distal colon. Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were markedly upregulated in the AOM-initiated and DSS-promoted colon tumors. The DNA binding activity of nuclear factor-kappaB (NF-kappa B) was also elevated in the colon tumors. In this study, we examined the chemopreventive effects of the standardized extract (DA-9601) of Artemisia asiatica that has been used in the traditional herbal medicine for the treatment of inflammatory disorders. Mice fed the chow diet containing 10% DA-9601 for 15 wk following DSS treatment displayed the significantly lower multiplicity of colon tumors. DA-9601 treatment suppressed the expression of COX-2 and iNOS as well as NF-kappa B DNA binding in the colonic tissues. It also downregulated the phosphorylation of extracellular, signal-regulated protein kinase and p38 mitogen-activated protein kinase that are upstream of NF-kappa B. Furthermore, DA-9601 reduced expression of beta-catenin in colonic mucosa of mice challenged with AOM plus DSS.

Modulation of inflammatory response via alpha2-adrenoceptor blockade in acute murine colitis

Inflammatory bowel disease (IBD) is characterized by heavy production of proinflammatory cytokines such as tumour necrosis factor (TNF)-alpha and interleukin (IL)-1beta. Interactions of the autonomic nervous system with local immune cells play an important role in the development of IBD, and the balance of autonomic nerve function is broken in IBD patients with sympathetic overactivity. However, the function of catecholamines in the progress of colitis is unclear. In this study, we examined the role of catecholamines via alpha2-adrenoreceptor in acute murine colitis. The expression of tyrosine hydroxylase (TH) and dopamine b-hydroxylase (DBH), two rate-limiting enzymes in catecholamine synthesis, was detected by immunohistochemistry in murine colitis. Murine colitis was induced by dextran sodium sulphate or trinitrobenzene sulphonic acid (TNBS), and the mice were administered RX821002 or UK14304, alpha2-adrenoceptor antagonists or agonists. Colitis was evaluated by clinical symptoms, myeloperoxidase assay, TNF-alpha and IL-1beta production and histology. Lamina propria mononuclear cells (LPMCs) from mice with TNBS colitis were cultured in the absence or presence of RX821002 or UK14304, and stimulated further by lipopolysaccharide. TH and DBH are induced in LPMCs of inflamed colon, the evidence of catecholamine synthesis during the process of colitis. RX821002 down-regulates the production of proinflammatory cytokines from LPMCs, while UK14304 leads to exacerbation of colitis. Together, our data show a critical role of catecholamines via alpha2-adrenoreceptors in the progress of acute colitis, and suggest that use of the alpha2-adrenoceptor antagonist represents a novel therapeutic approach for the management of colitis.

NF-kappaB p65 antisense oligonucleotides may serve as a novel molecular approach for the treatment of patients with ulcerative colitis

BACKGROUND

Activation of nuclear factor-kappa B (NF-kappaB), which controls transcription of various proinflammatory cytokine genes, has been shown to play a critical role in the pathogenesis of ulcerative colitis (UC). The aim of this study was to investigate if NF-kappaB p65 antisense oligonucleotides may affect the expression of NF-kappaB p65 and cytokines in lamina propria mononuclear cells (LPMCs) from patients with UC.

METHODS

LPMCs, which were isolated from intestinal mucosal biopsy specimens from patients with UC, were cultured with or without NF-kappaB p65 antisense oligonucleotides, missense oligonucleotides and dexamethasone. NF-kappaB p65 expression was determined by Western blot analysis. The expression of cytokine mRNA was studied by reverse transcription-polymerase chain reaction (RT-PCR). Cytokine levels were measured by enzyme-linked immunosorbent assay.

RESULTS

NF-kappaB p65 antisense oligonucleotides resulted in downregulation of NF-kappaB p65 expression, blocked the expression of IL-1beta mRNA and IL-8 mRNA, and strikingly reduced the production of IL-1beta and IL-8. These effects were greater than those of dexamethasone in cultured LPMCs from patients with UC (p <0.05).

CONCLUSIONS

Application of NF-kappaB p65 antisense oligonucleotides may serve as a novel molecular approach for the treatment of patients with UC.

Limited effects of dietary curcumin on Th-1 driven colitis in IL-10 deficient mice suggest an IL-10-dependent mechanism of protection

Curcumin (diferulolylmethane) demonstrates profound anti-inflammatory effects in intestinal epithelial cells (IEC) and in immune cells in vitro and exhibits a protective role in rodent models of chemically induced colitis, with its presumed primary mechanism of action via inhibition of NF-kappaB. Although it has been demonstrated effective in reducing relapse rate in ulcerative colitis patients, curcumin's effectiveness in Crohn's disease (CD) or in Th-1/Th-17 mediated immune models of CD has not been evaluated. Therefore, we investigated the effects of dietary curcumin (0.1-1%) on the development of colitis, immune activation, and in vivo NF-kappaB activity in germ-free IL-10(-/-) or IL-10(-/-);NF-kappaB(EGFP) mice colonized with specific pathogen-free microflora. Proximal and distal colon morphology showed a mild protective effect of curcumin only at 0.1%. Colonic IFN-gamma and IL-12/23p40 mRNA expression followed similar pattern ( approximately 50% inhibition at 0.1%). Secretion of IL-12/23p40 and IFN-gamma by colonic explants and mesenteric lymph node cells was elevated in IL-10(-/-) mice and was not decreased by dietary curcumin. Surprisingly, activation of NF-kappaB in IL-10(-/-) mice (phospho-NF-kappaBp65) or in IL-10(-/-);NF-kappaB(EGFP) mice (whole organ or confocal imaging) was not noticeably inhibited by curcumin. Furthermore, we demonstrate that IL-10 and curcumin act synergistically to downregulate NF-kappaB activity in IEC and IL-12/23p40 production by splenocytes and dendritic cells. In conclusion, curcumin demonstrates limited effectiveness on Th-1 mediated colitis in IL-10(-/-) mice, with moderately improved colonic morphology, but with no significant effect on pathogenic T cell responses and in situ NF-kappaB activity. In vitro studies suggest that the protective effects of curcumin are IL-10 dependent.

Blockade of CXCL12/CXCR4 axis ameliorates murine experimental colitis

Recent studies indicate that the CXCL12/CXCR4 interaction is involved in several inflammatory conditions. However, it is unclear whether this interaction has a role in the pathophysiology of inflammatory bowel disease (IBD). We investigated the significance of this interaction in patients with IBD and in mice with dextran sulfate sodium (DSS)-induced colitis and the effect of a CXCR4 antagonist on experimental colitis. First, we measured CXCR4 expression on peripheral T cells in patients with IBD. Furthermore, we investigated CXCR4 expression on leukocytes and CXCL12 expression in the colonic tissue of mice with DSS-induced colitis, and we evaluated the effects of a CXCR4 antagonist on DSS-induced colitis and colonic inflammation of interleukin (IL)-10 knockout (KO) mice. Colonic inflammation was assessed both clinically and histologically. Cytokine production from mesenteric lymph node cells was also examined. CXCR4 expression on peripheral T cells was significantly higher in patients with active ulcerative colitis (UC) compared with normal controls, and CXCR4 expression levels of UC patients correlated with disease activity. Both CXCR4 expression on leukocytes and CXCL12 expression in colonic tissue were significantly increased in mice with DSS-induced colitis. Administration of a CXCR4 antagonist ameliorated colonic inflammation in DSS-induced colitis and IL-10 KO mice. CXCR4 antagonist reduced tumor necrosis factor-alpha and interferon-gamma production from mesenteric lymph node cells, whereas it did not affect IL-10 production. The percentage of mesenteric Foxp3+CD25+ T cells in DSS-induced colitis was not affected by CXCR4 antagonist. These results suggest that blockade of this chemokine axis might have potential as a therapeutic target for the treatment of IBD.

Effects of NF-κB p65 antisense oligonucletide on the expression of cytokines and NF-κB in colonic intestinal mucosa of mice with TNBS-induced colitis

AIM: To evaluate the effects of nuclear factor kappa B (NF-κB) p65 antisense oligonucleotide on the inflammation, expression of cytokines such as tumor necrosis factor alpha (TNF-α), interleukins (IL-1β, IL-10) and NF-κB in colonic intestinal mucosa of mice with trinitrobenzene sulfonic acid-induced colitis.

METHODS: Fifty BALB/c mice were randomly divided into model control group (UC), antisense oligonucleotide treatment group (ASOND), missense oligonucleotide treatment group (MSOND), and sense oligonucleotide treatment group (SOND). Experimental colitis was induced by trinitrobenzene sulfonic acid (TNBS)/ethanol enema. Twenty-four hours after modeling, the mice in the ASOND, MSODN and SODN groups were administered with the corresponding oligonucleotides. Inflammatory scores and mucosal morphological changes were evaluated under light microscope. The leves of TNF-α, IL-1β, IL-10 and NF-κB were determined by immunohistochemistry.

RESULTS: The inflammatory scores in the ASOND group decreased as compared with those in the UC, MSOND and SOND group (all P < 0.05). The mucosal levels of TNF-α, IL-1β and NF-κB expression in the ASOND group were significantly lower than those in the UC, MSOND and SOND groups (82.68 ± 14.30 vs 168.48 ± 11.89, 166.49 ± 11.63, 176.49 ± 12.33, P < 0.05; 42.42 ± 5.77 vs 168.48 ± 11.89, 120.43 ± 28.21, 131.43 ± 30.601, P < 0.01; 62.66 ± 11.32 vs 158.38 ± 12.49, 161.09 ± 12.73, 168.64 ± 11.83, P < 0.01), while IL-10 levels were higher (146.68 ± 6.02 vs 62.50 ± 11.57, 58.44 ± 10.92, 54.24 ± 10.64, P < 0.01).

CONCLUSION: ASOND can attenuate the inflammatory degree in mice with experimental colitis and effectively down-regulates TNF-α, IL-1β and NF-κB expression while up-regulates IL-10 secretion. .

Saccharomyces boulardii decreases inflammation and intestinal colonization by Candida albicans in a mouse model of chemically-induced colitis

The present study was designed to investigate the effects of Saccharomyces boulardii on inflammation and intestinal colonization by Candida albicans in a BALB/c mouse model of colitis that had been induced by dextran-sulfate-sodium (DSS). Colonization with C. albicans was established by oral gavage with a 200 microL suspension of 10(7) yeast cells. A 1.5% solution of DSS was administered in drinking water 1 h after C. albicans oral challenge, while 10(7) cells of S. boulardii was inoculated daily by oral gavage for 1 week. Faeces were collected daily for 2 weeks. Seven groups of mice consisting of those that were administered either C. albicans or S. boulardii or both were sacrificed after 14 days and samples of the colon were taken for histological scoring and real-time PCR (RT-PCR) analysis of inflammatory cytokines and toll-like receptors (TLRs). Compared to control animals that did not receive DSS, the number of C. albicans colonies recovered from faeces was significantly greater in mice receiving DSS. In contrast, the colony forming units (CFUs) of C. albicans were greatly reduced in mice receiving S. boulardii. The administration of this yeast decreased the severity of DSS-induced clinical scores and histological inflammation. At the mRNA expression level, an increase in TLR2 and TLR4 resulting from the presence of S. boulardii was associated with a reduction in the inflammatory cytokines TNFalpha and INFgamma. In mice receiving DSS and C. albicans, TLR4 was over-expressed by stimulation with both yeasts, but TLR2 and TNFalpha, which were increased by the administration of C. albicans alone, were decreased in the presence of S. boulardii. These results indicate that S. boulardii decreased inflammation and C. albicans colonization in this BALB/c mouse model of colitis.

Effect of Kuijieling decoction on DNA binding activity of nuclear factor kappa B in colonic mucosa of rats with ulcerative colitis

AIM: To observe the changes of DNA binding activity of NF-κB as well as the effects of Kuijieling Decoction(KD)on DNA binding activity of NF-κB in colonic mucosa of ulcerative colitis (UC)model rats.

METHODS: Rat UC model was induced by trinitrobenzene-sulfonic acid (TNBS). The rats were randomly divided into normal control (NC) group, model control (MC) group, Kuijieling low dose (KLD) group, Kuijieling medium dose (KMD)group, Kuijieling high dose (KHD) group and salazossulfapridine (SASP) group. The rats were killed to get their fresh colonic mucosa and extract nuclear proteins after 10 days of treatment. Relative activity of NF-κB was detected by ELISA with a Trans AM TM NF-κB p65 kit.

RESULTS: The relative activity of NF-κB was significantly higher in the MC group than in the NC group (0.440 ± 0.119 vs 0.261 ± 0.042, P < 0.01). The relative activity of NF-κB was significantly lower in the KHD and SASP groups (0.261 ± 0.056 and 0.269 ± 0.106) than in the MC group (0.440 ± 0.119, P < 0.01).

CONCLUSION: NF-κB may be involved in the pathogenesis of UC, and KD can inhibit the relative activity of NF-κB in colonic mucosa of rats with UC induced by TNBS. The inhibitory effects of KD on UC might be associated with the inhibition of NF-κB activity.

Multipotential acceptance of Peyer's patches in the intestine for both thymus-derived T cells and extrathymic T cells in mice

Peyer's patches (PP) are important inductive sites for the mucosal immune response. It is well known that lymphocytes that migrate into PP are mainly of T-cell lineage from thymus-derived cells (i.e. alphabetaTCR(high) cells). In this study, we further characterized the properties of PP lymphocytes in mice using a mouse model of colitis induced by dextran sulphate sodium (DSS). Although the major site of the inflammation induced by DSS is known to be the large intestine, the small intestine was also damaged. When mice developed DSS-induced colitis, CD3+CD8+B220+ gammadelta T cells increased in PP in the small intestine. These gammadelta T cells, which are not seen in the PP of normal mice, resembled intraepithelial lymphocytes (IEL) in the small intestine in terms of their expression of CD5, CD103 and Thy1.2. In addition, the Vgamma/delta repertoire of these gammadelta T cells was similar to that of gammadelta IEL. When DSS-treated mice were injected with IEL isolated from normal mice, IEL including gammadelta T cells preferentially migrated to PP, raising the possibility that B220+ T cells seen in PP of diseased mice may derive from IEL in the small intestine. Our present study suggests that PP might be able to accept T-cell lineages from intestinal IEL as well as from thymus-derived T cells.

Inhibition of nuclear factor-kappaB ameliorates bowel injury and prolongs survival in a neonatal rat model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a major cause of morbidity and death in premature infants. NEC is associated with increased levels of pro-inflammatory cytokines in plasma and tissues that are regulated by the transcription factor nuclear factor-kappaB (NF-kappaB). It remains unknown, however, whether NF-kappaB mediates injury in neonatal NEC. We therefore examined the activation status of NF-kappaB perinatally in the small intestine and in a neonatal rat model of NEC. We found that intestinal NF-kappaB is strongly activated at birth and, in dam-fed newborn rats, is down-regulated within a day. In contrast, NF-kappaB remains strongly activated at both d 1 and d 2 in stressed animals, and this is accompanied by a significant decrease in the levels of the endogenous NF-kappaB inhibitor protein IkappaBalpha and IkappaBbeta at d 2. To determine the importance of elevated NF-kappaB activity in intestinal injury in NEC, we administered the NEMO-binding domain (NBD) peptide that selectively inhibits the critical upstream IkappaB kinase (IKK). NBD but not a control peptide decreased mortality and bowel injury in this model, supporting the hypothesis that bowel injury in NEC results from elevated NF-kappaB activity. Our findings therefore lead us to conclude that selective NF-kappaB inhibition represents a promising therapeutic strategy for NEC.

Blockade of STAT3 by antisense oligonucleotide in TNBS-induced murine colitis

BACKGROUND AND AIMS

The expression of signal transducers and activators of transcription 3 (STAT3) is increased in Crohn's disease (CD), and nuclear translocated STAT3 is also found in the disease. However, the role of STAT3 protein on the pathogenesis of CD is not clear. This study was executed to investigate the role of STAT3 protein on the pathogenesis of trinitrobenzene sulfonic acid (TNBS)-induced colitis, the pathogenesis of which is CD-like.

METHODS

TNBS-induced colitis was produced, and STAT3 antisense oligonucleotide was administrated intracolonically during the early phase of colitis. The mice were killed 7 days later, and the expressions of STAT3 and phosphorylated STAT3 were identified by Western blot and immunofluorescence. The lamina propria mononuclear cells (LPMCs) were isolated freshly, and the percent of cell death and the expressions of Bcl-2 and Bax in LPMCs were evaluated. Colonic tissue damage and the production of inflammatory cytokines were measured also.

RESULTS

Administration of STAT3 antisense oligonucleotide effectively inhibited STAT3 expression and phosphorylation in inflamed colonic mucosa of colitis. The mice that were administered STAT3 antisense oligonucleotide showed less colonic tissue damage with decreased production of inflammatory cytokines such as TNF-alpha and INF-gamma in mucosa compared with that of those TNBS-induced colitis. Administration of STAT3 antisense oligonucleotide successfully induced apoptosis of LPMCs and counteracted the unbalanced expressions of Bcl-2 and Bax in LPMCs from colitis.

CONCLUSIONS

STAT3 activation may play an important role in the inflammatory process of TNBS-induced colitis, and inhibiting STAT3 activation during the early phase of the inflammatory response may have a beneficial effect on the colitis.

Effects of the probiotic formulation VSL#3 on colitis in weanling rats

BACKGROUND

Only a few studies have used models of inflammatory bowel disease (IBD) with weanling animals. Previously, the effects of probiotics have not been assessed in such IBD models. The objectives of our study were 2-fold: to establish a suitable model of dextran sulfate sodium (DSS)-induced colitis in weanling rats and to determine the effects of the probiotic formulation VSL#3 on DSS-induced colitis in weanling animals.

MATERIALS AND METHODS

Rats were weaned on postnatal day 21 and administered 2%, 2.5%, or 3% (wt/vol) DSS in drinking water. In subsequent experiments, newly weaned animals were administered vehicle or VSL#3 (0.06, 0.6, or 6 mg) by orogastric gavage. These treatments were given to animals maintained on water (postnatal days 21-28) and then on DSS (postnatal days 28-35). Disease activity indices were determined on a routine basis. On day 35, rats were euthanized. The total colon length was determined. Other parameters of colitis were measured from the distal colon. These parameters included myeloperoxidase (MPO), interleukin (IL)-1beta, inhibitory kappaB-alpha (IkappaB-alpha), and histological assessment of crypt damage and inflammation.

RESULTS

DSS 2% was optimal for inducing colitis in weanling rats without significant morbidity. VSL#3 treatments improved various parameters of 2% DSS-induced colitis in weanling rats. The 0.6- and 6-mg doses of VSL#3 were most effective for attenuating this colitis.

CONCLUSIONS

The probiotic formulation VSL#3 improved DSS-induced colitis in weanling rats. This improvement of colitis involved changes in colonic IkappaB-alpha, IL-1beta, and MPO, which are suggestive of immune modulation by VSL#3.

Non-viral delivery of nuclear factor-kappaB decoy ameliorates murine inflammatory bowel disease and restores tissue homeostasis

BACKGROUND

Nuclear factor-kappaB (NF-kappaB) is a key transcriptional regulator of inflammatory bowel disease (IBD).

AIM

To investigate the therapeutic potential of a locally administered "non-viral" nuclear factor-kappaB decoy (NFkappaBD) in multiple experimental models of IBD.

METHODS

A fully phosphorothioated decoy oligonucleotide with improved stability that specifically binds NF-kappaB and blocks inflammatory mediators regulated by this transcription factor without the help of viral envelope-assisted delivery was developed. The therapeutic effects of NFkappaBD were studied in the trinitrobenzene sulphonic acid, oxazolone and dextran sodium sulphate induced colitis models.

RESULTS

Intracolonic administration of NFkappaBD results in the delivery of NFkappaBD to inflammatory cells and a reduction of NF-kappaB heterodimers. In the T helper cell 1-driven trinitrobenzene sulphonic acid-induced colitis model, mice receiving NFkappaBD treatment exhibit a dose-dependent reduction in disease severity and a more rapid recovery to normal body weight, similar to a clinically relevant dose of budesonide. Clinical efficacy was corroborated by considerable reductions in colitis pathology and tissue levels of several pro-inflammatory markers, including tumour necrosis factor alpha, interleukin 6, interleukin 1beta and monocyte chemotactic protein 1. NFkappaBD also mitigates disease activity in the T helper cell 2-like oxazolone colitis and epithelial injury-related acute dextran sodium sulphate colitis models. Interestingly, restoration of tissue homeostasis is observed in NFkappaBD-treated animals with the rapid re-emergence of functional goblet cells and a return to normal patterns of cell proliferation in the mucosal epithelium and smooth muscle cell layers.

CONCLUSIONS

These data support the potential use of "naked" NFkappaBD as a cross-functional therapeutic in IBD, and show for the first time that it can facilitate the restoration of colon homeostasis and function.

NF-kappa B as a therapeutic target in autoimmune disease

NF-kappaB transmits signals from the cell surface to the nucleus. Signaling through cell surface receptors to activate NF-kappaB and mitogen-activated protein kinases through adaptor molecules is of critical importance to survival and activation of all cells in the body, including those regulating innate and adaptive immunity. As such, NF-kappaB is a key signaling component in autoimmunity and an attractive target for autoimmune disease therapy. However, given its global importance, targeting NF-kappaB tends to be immunosuppressive. In this review, the authors discuss the roles played by NF-kappaB in autoimmunity, drugs which target it, and complexities which need to be addressed to improve the use of NF-kappaB as a target. Finally, the authors highlight some novel approaches that are likely to be important in the next generation of NF-kappaB therapies.

Evaluation of the effect of pyrrolidine dithiocarbamate in suppressing inflammation in mice with dextran sodium sulfate-induced colitis

AIM: To evaluate the effect of pyrrolidine dithio-carbamate (PDTC; an NF-κB inhibitor) administered at low (50 mg/kg) and high (100 mg/kg) doses in suppressing colitis in mice with dextran sodium sulfate (DSS)-induced colitis.

METHODS: Mice were divided into a DSS-untreated group (normal group), DSS-treated control group, DSS+PDTC-treated groupI(low-dose group), and DSS+PDTC-treated groupII (high-dose group). In each group, the disease activity index score (DAI score), intestinal length, histological score, and the levels of activated NF-κB and inflammatory cytokines (IL-1β and TNF-α) in tissue were measured.

RESULTS: The DSS+PDTC-treated groupII exhibited suppression of shortening of intestinal length and reduction of DAI score. Activated NF-κB level and IL-1β and TNF-α levels were significantly lower in DSS+PDTC-treated groupII.

CONCLUSION: These findings suggest that PDTC is useful for the treatment of ulcerative colitis.

Enhanced intestinal expression of the proteasome subunit low molecular mass polypeptide 2 in patients with inflammatory bowel disease

PURPOSE

Low molecular mass polypeptide 2 is an inducible immunoproteasome subunit. The expression of low molecular mass polypeptide 2 has not been examined in the intestine of patients with inflammatory bowel disease. This study was designed to determine whether the intestinal expression of low molecular mass polypeptide 2 was enhanced in a group of patients with inflammatory bowel disease compared with a group of control patients without inflammatory bowel disease. Moreover, we examined the association between low molecular mass polypeptide 2 expression and histologic pathology in these patients.

METHODS

Twenty-one patients participated in the study. These included six control subjects without inflammatory bowel disease, eight patients with ulcerative colitis, and seven patients with Crohn's disease. Intestinal low molecular mass polypeptide 2 expression was evaluated by immunohistochemistry, as well as by Western blot. Histology scores (0-40 severity scale) were determined on the same sections of intestine as those used for low molecular mass polypeptide 2 histochemistry.

RESULTS

By immunohistochemistry, low molecular mass polypeptide 2 expression was significantly enhanced (P < 0.05 vs. control subjects) throughout visibly diseased areas of colon, rectum, and ileum from patients with inflammatory bowel disease. Low molecular mass polypeptide 2 expression also was increased in macroscopically normal intestine from patients with inflammatory bowel disease compared with normal tissue from control subjects. There was a significant correlation (P < 0.0001) between low molecular mass polypeptide 2 expression and histologic pathology in our patients. Western blot results confirmed that low molecular mass polypeptide 2 expression was enhanced in patients with ulcerative colitis (3.1-fold) and in patients with Crohn's disease (3.5-fold).

CONCLUSIONS

Intestinal low molecular mass polypeptide 2 expression is significantly increased in inflammatory bowel disease. The association between intestinal low molecular mass polypeptide 2 expression and histologic pathology suggests that this proteasome subunit plays a role in the pathogenesis of inflammatory bowel disease.

Alleviation of neuropathic pain by intrathecal injection of antisense oligonucleotides to p65 subunit of NF-kappaB

BACKGROUND

Treatment of neuropathic pain remains a challenge. The current study investigated the therapeutic effect of intrathecal administration of NF-kappaB antisense oligodeoxynucleotides (ODNs) on mechanical allodynia and thermal hyperalgesia in a chronic constriction injury (CCI) model of rats.

METHODS

Lumbar intrathecal catheters were implanted in male Sprague-Dawley rats and a CCI model was established. Thermal and mechanical nociceptive thresholds were assessed with paw withdrawal latency (PWL) to radiant heat and von Frey filaments. The phosphorothioate-modified antisense ODNs to p65 subunit of NF-kappaB were administered intrathecally on each of five consecutive days post-CCI. Nuclear NF-kappaB p65 expression was assessed by western blot.

RESULTS

CCI induced mechanical allodynia and thermal hyperalgesia and significantly increased NF-kappaB p65 protein expression. Intrathecal injection of antisense ODN markedly suppressed the expression of NF-kappaB p65 protein and significantly attenuated CCI-induced mechanical allodynia and thermal hyperalgesia.

CONCLUSION

The activation of NF-kappaB pathway may contribute to neuropathic pain in CCI rats. Suppression of NF-kappaB could be a potential new strategy for the treatment of neuropathic pain.

Engineering mucosal RNA interference in vivo

Mucosal surfaces serve as a gateway to disease. Here, we demonstrate that RNA interference can be used to manipulate mucosal gene expression in vivo. Using a murine model, we show that direct application of liposome-complexed siRNA mediates gene-specific silencing in cervicovaginal and rectal mucosa. A single vaginal or rectal administration of siRNA targeting hematopoietic or somatic cell gene products reduced corresponding mRNA levels by up to 90%. Using a murine model of inflammatory bowel disease, we found that the rectal application of siRNA targeting TNF-alpha led to relative mucosal resistance to experimental colitis. Liposomal siRNA formulations proved nontoxic, did not elicit a nonspecific interferon response, and provide a means for genetic engineering of mucosal surfaces in vivo.

NF-kappaBp65-specific siRNA inhibits expression of genes of COX-2, NOS-2 and MMP-9 in rat IL-1beta-induced and TNF-alpha-induced chondrocytes

OBJECTIVE

Small interfering RNA (siRNA) triggers RNA interference in mammalian somatic cells. Nuclear factor kappaB (NF-kappaB) is a transcription factor that is implicated in inflammation and immune activation. This study was to use NF-kappaBp65-specific siRNA to inhibit the expression of genes of cyclooxygenase-2 (COX-2), nitric oxide synthase-2 (NOS-2) and matrix metalloproteinase-9 (MMP-9), which is paralleled with the initiation and progression of cartilage lesions in osteoarthritis (OA) model, in induced chondrocytes, and therefore to explore a new gene therapy for OA.

METHODS

Western blot and reverse transcriptase polymerase chain reaction (RT-PCR) were performed to optimize the silencing effects of NF-kappaBp65-specific siRNA in cultured rat chondrocytes, and then to determine the expression of COX-2, NOS-2 and MMP-9 in induced chondrocytes. The activation of NF-kappaB was determined by electrophoretic mobility shift assay (EMSA). Western blot and RT-PCR were subjected to densitometric analysis and then band intensities were also determined.

RESULTS

The NF-kappaBp65-specific siRNA inhibited the expression of NF-kappaBp65 and activation of NF-kappaB, reducing significantly the expression of COX-2, NOS-2 and MMP-9 induced by interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in cultured chondrocytes.

CONCLUSIONS

NF-kappaBp65-specific siRNA can inhibit the expression of COX-2, NOS-2 and MMP-9 in IL-1beta-induced and TNF-alpha-induced chondrocytes. This suggests that NF-kappaBp65-specific siRNA has potential to be a useful, preventive and therapeutic agent for OA at early stages.

Chronic inflammation and pathogenesis of GI and pancreatic cancers

The pathogenesis of cancer represents a complex and multifactorial process requiring a number of acquired and genetic defects. It is becoming increasingly apparent that many cancers originate from a chronic inflammatory process. The topic of this review is the inflammatory response and development of gastrointestinal (GI) and pancreatic cancers. Here, we describe the development of various gastric colorectal and pancreatic cancers through an inflammatory process. The tumor microenvironment which predisposes to tissue destruction, subsequent attempts at healing and accumulation of cellular damage with loss of cell cycle control mechanisms is discussed. Components of the tumor microenvironment that are important in the final common pathway leading to cancer include the tumor stroma, tumor-associated macrophages, cytokines and chemokines and reactive oxygen and nitrogen species. Common signaling pathways that link inflammation with cancer are described and include the COX-2, NF-kappaB and phosphatidyl inositol 3-kinase (PI3K) pathways. Finally, therapies that can be directed to the inflammatory process as either treatment or prevention of these cancers will be discussed including novel inhibitors of signaling pathways which are currently in development.

Carboxylated glycans mediate colitis through activation of NF-kappa B

The role of carbohydrate modifications of glycoproteins in leukocyte trafficking is well established, but less is known concerning how glycans influence pathogenesis of inflammation. We previously identified a carboxylate modification of N-linked glycans that is recognized by S100A8, S100A9, and S100A12. The glycans are expressed on macrophages and dendritic cells of normal colonic lamina propria, and in inflammatory infiltrates in colon tissues from Crohn's disease patients. We assessed the contribution of these glycans to the development of colitis induced by CD4(+)CD45RB(high) T cell transfer to Rag1(-/-) mice. Administration of an anti-carboxylate glycan Ab markedly reduced clinical and histological disease in preventive and early therapeutic protocols. Ab treatment reduced accumulation of CD4(+) T cells in colon. This was accompanied by reduction in inflammatory cells, reduced expression of proinflammatory cytokines and of S100A8, S100A9, and receptor for advanced glycation end products. In vitro, the Ab inhibited expression of LPS-elicited cytokines and induced apoptosis of activated macrophages. It specifically blocked activation of NF-kappaB p65 in lamina propria cells of colitic mice and in activated macrophages. These results indicate that carboxylate-glycan-dependent pathways contribute to the early onset of colitis.

Topical antisense oligonucleotide therapy against LIX, an enterocyte-expressed CXC chemokine, reduces murine colitis

Epithelial neutrophil-activating peptide-78 (ENA-78), a member of the CXC chemokine subfamily, is induced by inflammatory cytokines in human colonic enterocyte cell lines and increased in the colon of patients with inflammatory bowel disease (IBD). Lipopolysaccharide-induced CXC-chemokine (LIX) was recently identified as the murine homolog of ENA-78. Here we show that, similar to ENA-78, inflammatory cytokine stimulation of a murine colonic epithelial cell line, MODE-K, results in increased LIX expression. Consistent with the expression pattern of ENA-78 in IBD, LIX expression is significantly increased in mice with colitis induced by the ingestion of dextran sodium sulfate (DSS). Treating mice with antisense oligonucleotides to LIX via rectal enema delivery before DSS treatment results in colonic enterocyte uptake and a significant reduction in neutrophil infiltration and severity of colitis. These findings indicate that LIX plays an integral role in the pathogenesis of DSS-induced colitis. Similarly, enterocyte-derived CXC chemokines may play a key role in regulating neutrophil recruitment and intestinal injury in IBD. The intracolonic administration of ENA-78 antisense oligonucleotides may be effective in treating distal ulcerative colitis in humans.

NF-kappaB activation precedes increases in mRNA encoding neurokinin-1 receptor, proinflammatory cytokines, and adhesion molecules in dextran sulfate sodium-induced colitis in rats

Nuclear factor kappa B (NF-kappa B) plays a key role in initiating inflammation associated with colitis. A systematic study was conducted in the rat DSS colitis model to determine the temporal relationship between NF-kappa B activation and expression of substance P (SP), neurokinin-1 receptor (NK-1R), proinflammatory cytokines, and adhesion molecules. Rats were given 5% DSS in their water and sacrificed daily for 6 days. Colon tissue was collected for assessment of histological changes, NF-kappa B activation, myeloperoxidase (MPO) activity, and expression of NK-1R, SP, TNFalpha, IL-1beta, VCAM-1, ICAM-1, E-selectin, CINC-1, MIP-1alpha, and iNOS. NF-kappa B activation increased, biphasically, on Day 1 and again on Days 4-6. The mRNA levels for ICAM-1, CINC-1, IL-1beta, TNFalpha, VCAM-1, and NK-1R rose significantly (P < 0.05) by 2-4 days. Increased iNOS mRNA levels, MPO activity, and mucosal damage occurred on Day 6. These data demonstrate that NF-kappa B activation substantially precedes the onset of physical disease signs and active inflammation.

Inhibition of proinflammatory cytokine expression by NF-kappaB (p65) antisense oligonucleotide in Helicobacter pylori-infected mice

BACKGROUND

Helicobacter pylori induces the expression of proinflammatory cytokines in vitro by activating nuclear factor-kappaB, a transcriptional regulator. However, it has not been clarified whether H. pylori-induced proinflammatory cytokines are also mediated through nuclear factor-kappaB in vivo. The aim of this study was to evaluate the role of nuclear factor-kappaB on the expressions of proinflammatory cytokines in H. pylori-infected mice.

MATERIALS AND METHODS

We evaluated nuclear factor-kappaB (p65) activation in the H. pylori-infected gastric mucosa of mice by immunofluorescent staining using antip65 polyclonal antibody, and the expressions of proinflammatory cytokines with inhibition of nuclear factor-kappaB pathway by using phosphorothioate antisense and sense oligonucleotide against the nuclear factor-kappaB (p65).

RESULTS

In the H. pylori-infected gastric mucosa of mice, immunofluorescent staining using antip65 polyclonal antibody showed nuclear factor-kappaB (p65) activation, which was particularly localized to epithelial cells. Tumor necrosis factor-alpha and interleukin-1beta concentrations in gastric mucosa by enzyme-linked immunosorbent assay (ELISA) were elevated in the infected group versus the uninfected group. Pretreatment with nuclear factor-kappaB (p65) antisense oligonucleotide inhibited the activation of nuclear factor-kappaB and the expressions of tumor necrosis factor-alpha and interleukin-1beta in H. pylori-infected gastric mucosa. Sense oligonucleotide did not influence on the expression of proinflammatory cytokines.

CONCLUSIONS

H. pylori infection was found to activate the expressions of proinflammatory cytokines via nuclear factor-kappaB in vivo, and this may play an important role in the initiation of H. pylori-induced gastric inflammation.

Effects of Huoxue, Jianpi and Bushen recipe on expression of TNF-α and its mRNA in mice with colitis

AIM: To observe the expression of tumor necrosis factor-a (TNF-α) and its mRNA in colitis mice, and to explore the effects of Huoxue Jianpi Bushen recipe on it.

METHODS: The mouse model of ulcerative colitis was induced by dextran sulfate sodium (DSS). The mice were randomly divided into six groups: normal control, model, sulfasalazine (SASP), Huoxun, Jianpi, and Bushen group. The expression of TNF-α and its mRNA in the mice were examined by immunohistochemistry and in situ hybridization.

RESULTS: The colonic histological scores (for inflam-mation, depth of the illness, damage of the recess) of the mice in the model group were 4.85±2.1, 5.77±2.2, and 7.76±2.4, respectively, which were significantly higher than those in Huoxue group (2.24±2.4, 2.53±2.5, 3.49±2.3), Jianpi group (2.76±2.2, 2.89±2.4, 3.87±2.3), and Bushen group (2.12±2.3, 2.33±2.2, 3.44±2.4) (all P < 0.05). The expression of TNF-α (integral after staining, mean optical density, mean grey) in model group (6.8±1.4, 0.35±0.03, 78.6±4.4) was significantly different from those in Huoxue group (3.7±1.1, 0.18±0.05, 137.9±6.7), Jianpi group (3.4±1.3, 0.16±0.03, 155.1±8.8), and Bushen group (3.1±1.5, 0.17±0.04, 145.62±7.6)(all P < 0.05).

CONCLUSION: TNF-α plays an important role in the occurrence of ulcerative colitis induced by DSS, and the recipe of Huoxue, Jianpi, and Bushen can prevent and cure this disease by down-regulating the expression of TNF-α.

Anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium-induced colitis of rats

AIM: To investigate the anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium (DSS)-induced colitis of rats.

METHODS: Acute colitis was induced by giving 2% DSS orally in drinking water for 8 d. Twenty-six male rats were randomized into oxymatrine-treated group (group A, 10 rats), DSS control (group B, 10 rats) and normal control (group C, 6 rats). The rats in group A were injected muscularly with oxymatrine at the dosage of 63 mg/(kg穌) from d 1 to 11 and drank 2% DSS solution from d 4 to 11. The rats in group B were treated with 0.9% saline in an equal volume as group A and drank 2% DSS solution from d 4 to 11. The rats in group C were treated with 0.9% saline as group B from d 1 to 11 and drank water normally. Diarrhea and bloody stool as well as colonic histology were observed. The levels of serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined by ELISA, and nuclear factor-κB (NF-κB) activity and the expression of inter-cellular adhesion molecule-1 (ICAM-1) in colonic mucosa were detected by immunohistochemistry method.

RESULTS: Compared with DSS control group, the inflammatory symptoms and histological damages of colonic mucosa in oxymatrine-treated group were significantly improved, the serum levels of TNF-α, IL-6, and the expression of NF-κB, ICAM-1 in colonic mucosa were significantly reduced.

CONCLUSION: The fact that oxymatrine can reduce the serum levels of TNF-α, IL-6, and the expression of NF-κB and ICAM-1 in colonic mucosa in DSS-induced colitis of rats indicates that oxymatrine may ameliorate the colonic inflammation and thus alleviate diarrhea and bloody stool.

Treatment of Experimental Septic Shock with Microencapsulated Antisense Oligomers to NF-κB

NF-kappaB is an ideal target for inhibition of proinflammatory cytokines. The purpose of this study was to determine if microencapsulated antisense oligomer to NF-kappaB can inhibit proinflammatory cytokine release in response to Escherichia coli endotoxin and bacteria. Microencapsulation takes advantage of the phagocytic function of the macrophage to deliver the oligomer intracellularly and enhance the effect. Albumin microcapsules 1 microm in size were prepared by a nebulization method containing antisense oligomers to NF-kappaB. E. coli endotoxin was incubated in 1 ml aliquots of whole blood. Microencapsulated antisense to NF-kappaB was given, and the inhibition of tumor necrosis factor (TNF), interleukin-1 (IL-1), IL-6, and IL-8 was compared with similar amounts of oligomer in solution. Endotoxic shock was produced in rats using E. coli endotoxin (15 mg/kg). Peritonitis was induced by injecting 10(10) CFU E. coli. Cytokines were measured after simultaneous and delayed (4 h) administration of antisense to NF-kappaB in microcapsules and solution form. TNF was suppressed by 81% in whole blood, 56% in the endotoxic shock model, 89% in the peritonitis model (simultaneous treatment), and 56% in the delayed treatment group. Survival was 70% in the endotoxic shock group, 80% in the simultaneous peritonitis group, and 70% in the delayed treatment group. Microcapsule treatment using antisense to NF-kappaB suppressed TNF and IL-1 levels and mortality significantly better than all solution treatment groups in the whole blood model, endotoxic shock model, and peritonitis model.

Heme oxygenase-1-generated biliverdin ameliorates experimental murine colitis

BACKGROUND

Heme oxygenase-1 (HO-1) seems to have an important protective role in acute and chronic inflammation. The products of heme catalysis, biliverdin/bilirubin, carbon monoxide (CO), and iron (that induces apoferritin) mediate the beneficial effects of HO-1. Blockade of HO-1 activity results in exacerbation of experimental colitis. We tested whether HO-1 has protective effects in the development of colitis and determined that specific enzymatic products of HO-1 are responsible for these effects.

METHODS

Colitis was induced by oral administration of dextran sodium sulfate (5%) to C57BL/6 mice for 7 days. HO-1 was up-regulated by cobalt-protoporphyrin (5 mg/kg, intraperitoneally). Biliverdin, exogenous CO, or the iron chelator desferrioxamine was administered to other groups.

RESULTS

Cobalt-protoporphyrin treatment resulted in significant up-regulation of HO-1 protein in mucosal and submucosal cells. Induction of HO-1 was associated with significantly less loss of body weight in mice with induced colitis (-12% versus -22% in the control animals, P < 0.001). Development of diarrhea and gastrointestinal hemorrhage was substantially delayed in animals in which HO-1 was induced, and mucosal injury was significantly attenuated. Administration of CO or desferrioxamine alone had no significant effects, whereas enhanced protection with lesser evidence of bowel inflammation was observed with systemic biliverdin administration (50 micromol/kg, 3 times per day, intraperitoneally).

CONCLUSIONS

We conclude that heightened HO-1 expression or administration of biliverdin ameliorates dextran sodium sulfate-induced experimental colitis. Novel therapeutic strategies based on HO-1 and/or biliverdin administration may have use in inflammatory bowel disease.

Animal models of inflammatory bowel disease

In inflammatory bowel disease (IBD), experimental models have proven to be important tools for detecting potential therapeutic agents and for investigating the mechanisms of pathogenesis. This review is intended to cover recent advances in basic IBD model applications. The use of more than 20 animal models has allowed the detection of numerous protective pharmacological agents, including a number of immunomodulatory agents that have entered the therapeutic armamentarium. The models have been classified into five main categories based on the methods of induction: gene knockout (KO), transgenic, chemical, adoptive transfer, and spontaneous (each with subcategories).

MAdCAM-1 expression and regulation in murine colonic endothelial cells in vitro

BACKGROUND

Although the mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is associated with the etiology of inflammatory bowel diseases, few studies have directly examined MAdCAM-1 using microvascular endothelium derived from the colon. This study measured the expression of MAdCAM-1 in a novel colon endothelial line MJC-1, as well as MAdCAM-1 regulation and function in vitro.

METHODS

We cloned microvascular endothelial cells from primary colon cultures using ImmortoMice mice (whose cells express a temperature-sensitive SV40 large T antigen, H-2Kb-tsA58 mice). Expression of MAdCAM-1 after stimulation with cytokines [tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, or interferon (IFN)-gamma] was determined by Western blotting. Signal paths regulating MAdCAM-1 expression were examined using pharmacological blockers before cytokines. We also examined lymphocyte adhesion using lymphocytes that constitutively express alpha4beta7 integrin.

RESULTS

TNF-alpha induced MAdCAM-1 in a dose-dependent manner by 24 hours. MAdCAM-1 induction was protein kinase C, tyrosine kinase, p38 mitogen activated protein kinase, and nuclear-factor kappa-B/poly adenosine diphosphate ribose polymerase dependent. Lymphocyte adhesion was increased 2.6-fold after TNF-alpha stimulation and was inhibited by anti-MAdCAM-1 antibody before treatment (P < 0.05 control versus TNF-alpha).

CONCLUSIONS

In vitro, MAdCAM-1 can be induced on colon endothelial cells by TNF-alpha stimulation and may represent a useful model to study microvascular injury in the large intestine.

IKKbeta links inflammation and tumorigenesis in a mouse model of colitis-associated cancer

A link between inflammation and cancer has long been suspected, but its molecular nature remained ill defined. A key player in inflammation is transcription factor NF-kappaB whose activity is triggered in response to infectious agents and proinflammatory cytokines via the IkappaB kinase (IKK) complex. Using a colitis-associated cancer model, we show that although deletion of IKKbeta in intestinal epithelial cells does not decrease inflammation, it leads to a dramatic decrease in tumor incidence without affecting tumor size. This is linked to increased epithelial apoptosis during tumor promotion. Deleting IKKbeta in myeloid cells, however, results in a significant decrease in tumor size. This deletion diminishes expression of proinflammatory cytokines that may serve as tumor growth factors, without affecting apoptosis. Thus, specific inactivation of the IKK/NF-kappaB pathway in two different cell types can attenuate formation of inflammation-associated tumors. In addition to suppressing apoptosis in advanced tumors, IKKbeta may link inflammation to cancer.

Pathophysiological significance of a reaction in mouse gastrointestinal tract associated with delayed-type hypersensitivity

AIM: To explore the pathophysiological significance of delayed type hypersensitivity (DTH) reaction in mouse gastrointestinal tract induced by an allergen 2,4-dinitrochlorobenzene (DNCB).

METHODS: BALB/c mice were randomly divided into control and DTH_1-6 groups. After sensitized by DNCB smeared on the abdominal skin, the mice were challenged with DNCB by gavage or enema. The weight, stool viscosity and hematochezia were observed and accumulated as disease active index (DAI) score; the gastrointestinal motility was represented by active charcoal propulsion rate; the colon pathological score was achieved by macropathology and HE staining of section prepared for microscopy; and the leukocyte migration inhibitory factor (LMIF) activity was determined by indirect capillary assay of the absorbance (A) of migrated leukocytes.

RESULTS: Active charcoal propulsion rates of small intestine in the DNCB gavages groups were significantly higher than that in the control group (P < 0.01). The DAI scores and pathological score in DNCB enema groups were also higher than that in the control group ( P < 0.05), and there were significant rises in LMIF activity in DNCB enema groups as compared with control groups (P < 0.01).

CONCLUSION: Mouse gastrointestinal DTH reaction could be induced by DNCB, which might facilitate the mechanism underlying the ulcerative colitis.

Pioglitazone, a PPAR-gamma ligand, provides protection from dextran sulfate sodium-induced colitis in mice in association with inhibition of the NF-kappaB-cytokine cascade

Nuclear factor-kappaB-dependent up-regulation of inflammatory cytokines occurs in inflammatory bowel disease. We investigated the effect of pioglitazone, a peroxisome proliferator-activated receptor-gamma ligand, on dextran sulfate sodium-induced colonic mucosal injury and inflammation in mice. Acute colitis was induced in female mice receiving 0, 1, 3, and 10 mg/kg i.p. of pioglitazone daily. Colonic mucosal inflammation was evaluated chemically and histologically. Thiobarbituric acid-reactive substances and tissue-associated myeloperoxidase activity were measured in intestinal mucosa as indices of lipid peroxidation and neutrophil infiltration, respectively. Colonic mRNA expression of pro-inflammatory cytokines and inducible nitric oxide synthase was measured by reverse transcription-PCR and nuclear factor-kappaB activation was evaluated by electrophoretic mobility shift assay. Dextran sulfate sodium administration resulted in decreases in body weight and colon length and increases in lipid peroxide and neutrophil accumulation of the intestine. In contrast, co-administration with pioglitazone prevented these changes. Transcripts coding for pro-inflammatory cytokines and inducible nitric oxide were expressed in high levels after the development of colitis, and pioglitazone markedly reduced mRNA expression of these genes. DNA binding activity of nuclear factor-kappaB was markedly increased, whereas in pioglitazone co-treated intestines the effect was significantly reduced. These data suggest that peroxisome proliferator-activated receptor-gamma may be a novel therapeutic target for the therapy of inflammatory bowel disease.

The heat shock response and cytoprotection of the intestinal epithelium

Following heat stress, the mammalian intestinal epithelial cells respond by producing heat shock proteins that confer protection under stressful conditions, which would otherwise lead to cell damage or death. Some of the noxious processes against which the heat shock response protects cells include heat stress, infection, and inflammation. The mechanisms of heat shock response-induced cytoprotection involve inhibition of proinflammatory cytokine production and induction of cellular proliferation for restitution of the damaged epithelium. This can mean selective interference of pathways, such as nuclear factor kappa B (NF-kappaB) and mitogen-activated protein kinase (MAPK), that mediate cytokine production and growth responses. Insight into elucidating the exact protective mechanisms could have therapeutic significance in treating intestinal inflammations and in aiding maintenance of intestinal integrity. Herein we review findings on heat shock response-induced intestinal epithelial protection involving regulation of NF-kappaB and MAPK cytokine production.

Anti-inflammatory activities of human lactoferrin in acute dextran sulphate-induced colitis in mice

In this study, we investigated the anti-inflammatory effects of orally administered human lactoferrin (hLF) and two peptides, based on the bactericidal region of hLF (HLD1 and HLD2), on the course of experimental colitis. Acute colitis was induced in C57Bl/6 mice by giving 5% dextran sulphate (DX) in the drinking water. The mice were killed after 2 or 7 days of DX exposure. The animals were given hLF or the peptides orally twice a day (2 mg/dose/mouse) during the DX exposure. In the control animals, the hLF or the peptides were replaced by bovine serum albumin or water. The appearance of occult blood in the faeces and macroscopic rectal bleeding were significantly delayed and partly reduced in the hLF-treated animals compared with the control animals. The shortening of the colon, a pathological effect of DX exposure, was significantly less pronounced in the hLF-treated group compared with the control group. Also, the interleukin-1beta (IL-1beta) levels in the blood were significantly diminished in this group after 2 days of DX exposure. A significantly lower crypt score was observed in the distal part of the colon in the hLF-treated group compared with the control group. Also, significantly reduced numbers of CD4 cells, F4/80-positive macrophages and tumour necrosis factor-alpha-producing cells were detected by immunohistochemistry in the distal colon of the hLF-treated animals compared with the control animals after 7 days of DX exposure. A reduction was also observed concerning the IL-10-producing cells in the middle colonic submucosa. The HLD1 and HLD2 treatment, which was carried out for 2 days, only gave results almost identical to those of hLF, concerning clinical parameters after the 2 days of DX exposure. An even stronger effect was observed for HLD2, regarding decreased occult blood in the faeces and colon length. Our results show that perorally given hLF mediates anti-inflammatory effects on the DX-induced acute colitis, and further suggest that the bactericidal region of the hLF molecule may be involved in these activities.

Overexpression of alpha(1)-acid glycoprotein in transgenic mice leads to sensitisation to acute colitis

BACKGROUND

alpha(1)-Acid glycoprotein (alpha(1)-AGP) is an acute phase protein in most mammalian species whose concentration rises 2-5-fold during an acute phase reaction. Its serum concentration has often been used as a marker of disease, including inflammatory bowel disease (IBD). High alpha(1)-AGP levels were found to have a prognostic value for an increased risk of relapse in IBD.

AIMS

To investigate a possible role for increased serum levels of alpha(1)-AGP in the development of IBD.

METHODS

Dextran sodium sulphate (DSS) 2% was added to the drinking water of transgenic mice, overexpressing the rat alpha(1)-AGP gene, to induce acute colitis, thus mimicking the conditions of relapse. Clinical parameters, inflammatory parameters, and histological analyses on colon sections were performed.

RESULTS

Homozygous alpha(1)-AGP-transgenic mice started losing weight and showed rectal bleeding significantly earlier than heterozygous transgenic or wild-type mice. Survival time of homozygous transgenic mice was significantly shorter compared with heterozygous and wild-type mice. The higher susceptibility of homozygous alpha(1)-AGP-transgenic mice to DSS induced acute colitis was also reflected in higher local myeloperoxidase levels, higher inflammation scores of the colon, and higher systemic levels of interleukin 6 and serum amyloid P component. Local inflammatory parameters were also significantly different in heterozygous transgenic mice compared with wild-type mice, indicating a local dosage effect. In homozygous transgenic mice, significantly higher amounts of bacteria were found in organs but IgA levels were only slightly lower than those of control mice.

CONCLUSION

Sufficiently high serum levels of alpha(1)-AGP result in a more aggressive development of acute colitis.

Inhibition of chronic ulcerative colitis-associated colorectal adenocarcinoma development in a murine model by N-acetylcysteine

Long-term ulcerative colitis (UC) patients are at increased risk for developing colorectal cancer. In order to develop strategies for preventing UC-associated carcinogenesis, we studied the effect of the antioxidant N-acetylcysteine (NAC) on UC-associated cancer development in a mouse model. Female C57BL/6J mice were subjected to long-term administration of dextran sulfate sodium (DSS) in the drinking fluid and 2-fold iron-enriched AIN76A diet, with or without NAC. In the DSS-plus-2-fold iron positive control group, gross tumor incidence was 88.5% (23/26 mice) after 12 DSS cycles (1 DSS cycle = 7 day DSS treatment period followed by 10 day recovery period). The tumor multiplicity was 2.1 +/- 0.2 tumors/tumor-bearing mouse, and the tumor volume was 0.054 +/- 0.019 cm3. With 0.2% NAC administration, tumor incidence was significantly reduced (68%, 17/25 mice; P < 0.05), as was the tumor multiplicity (1.5 +/- 0.1 tumors/tumor-bearing mouse; P < 0.05). The tumor volume was lower (0.014 +/- 0.004 cm3), but not significantly decreased. The proliferation index was significantly decreased in non-cancerous epithelia (48.5 +/- 6.0% vs 32.0 +/- 3.7%; P < 0.05), but not in tumor cells. NAC significantly induced apoptosis in both non-cancerous epithelia and colorectal adenocarcinoma. The number of cells immunostained-positive for nitrotyrosine was markedly decreased in the non-cancerous mucosa of NAC-treated mice (102.4 +/-16.6 positive cells/mm2 mucosa vs 53.6 +/- 14.9 cells/mm2; P < 0.05). In addition, the number of inducible nitric oxide synthase (iNOS)-positive inflammatory cells in the non-cancerous mucosa of the distal colon was markedly decreased by NAC. This study indicates that the antioxidant NAC has the potential to serve as a preventive agent for UC-associated colorectal cancer, possibly via inhibition of cellular proliferation and nitrosative stress-caused cellular damage.

Small therapeutic molecules for the treatment of inflammatory bowel disease

New therapies for inflammatory bowel disease are needed, because standard therapies fail to induce remission in about 30% of patients, and because of the relative inefficacy of current maintenance therapies. This review summarises the current status of the development of small therapeutic molecules for inflammatory bowel disease.

The heat shock response and cytoprotection of the intestinal epithelium

Following heat stress, the mammalian intestinal epithelial cells respond by producing heat shock proteins that confer protection under stressful conditions, which would otherwise lead to cell damage or death. Some of the noxious processes against which the heat shock response protects cells include heat stress, infection, and inflammation. The mechanisms of heat shock response-induced cytoprotection involve inhibition of proinflammatory cytokine production and induction of cellular proliferation for restitution of the damaged epithelium. This can mean selective interference of pathways, such as nuclear factor kappa B (NF-kappaB) and mitogen-activated protein kinase (MAPK), that mediate cytokine production and growth responses. Insight into elucidating the exact protective mechanisms could have therapeutic significance in treating intestinal inflammations and in aiding maintenance of intestinal integrity. Herein we review findings on heat shock response-induced intestinal epithelial protection involving regulation of NF-kappaB and MAPK cytokine production.

alpha-Phenyl-N-tert-butylnitrone provides protection from dextran sulfate sodium-induced colitis in mice

Nuclear factor-kappaB (NF-kappaB)-dependent up-regulation of inflammatory cytokines and inducible nitric oxide (iNOS) occurs in inflammatory bowel disease. We investigated the effect of alpha-phenylN-tert-butylnitrone (PBN), a spin-trapping agent that inhibits NF-kappaB activity, on dextran sulfate sodium (DSS)-induced colonic mucosal injury and inflammation in mice. Acute colitis was induced with DSS in female BALB/c mice receiving 0, 0.3, 3, and 30 mg/kg i.p. PBN daily. Colonic mucosal inflammation was evaluated biochemically and histologically. Nitric oxide was evaluated as luminal nitrite/nitrite concentration by the Griess reaction and as immunoreactive nitrotyrosine in mucosal cells. Mucosal tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were determined by immunoassay. Colonic mRNA expression for iNOS, TNF-alpha, and IFN-gamma was measured by reverse transcription-polymerase chain reaction, and NF-kappaB activation was evaluated by electrophoretic mobility shift assay. After DSS administration, mice showed increased luminal nitrite/nitrate, mucosal TNF-alpha and IFN-gamma, and mRNA for iNOS and these cytokines, in addition to decreased colonic length and increased inflammatory score, luminal hemoglobin, and colonic myeloperoxidase activity. PBN inhibited increases in luminal nitric oxide production, nitrotyrosine immunoreactivity, and mucosal TNF-alpha and IFN-gamma. Colonic iNOS, TNF-alpha, and IFN-gamma mRNA were suppressed by PBN, as was a DSS-induced increase in colonic NF-kappaB DNA-binding activity. NF-kappaB is essential to DSS-induced colitis, suggesting molecular approach targeting of NF-kappaB for treatment of inflammatory bowel disease.

Regulation and distribution of MAdCAM-1 in endothelial cells in vitro

Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is a 60-kDa endothelial cell adhesion glycoprotein that regulates lymphocyte trafficking to Peyer's patches and lymph nodes. Although it is widely agreed that MAdCAM-1 induction is involved in chronic gut inflammation, few studies have investigated regulation of MAdCAM-1 expression. We used two endothelial lines [bEND.3 (brain) and SVEC (high endothelium)] to study the signal paths that regulate MAdCAM-1 expression in response to tumor necrosis factor (TNF)-alpha using RT-PCR, blotting, adhesion, and immunofluorescence. TNF-alpha induced both MAdCAM-1 mRNA and protein in a dose- and time-dependent manner. This induction was tyrosine kinase (TK), p42/44, p38 mitogen-activated protein kinase (MAPK), and nuclear factor (NF)-kappa B/poly-ADP ribose polymerase (PARP) dependent. Because MAdCAM-1 is regulated via MAPKs, we examined mitogen/extracellular signal-regulated kinase (MEK)-1/2 activation in SVEC. We found that MEK-1/2 is activated by TNF-alpha within minutes and is dependent on TK and p42/44 MAPKs. Similarly, TNF-alpha activated NF-kappa B through TK, p42/44, p38 MAPKs, and PARP pathways in SVEC cells. MAdCAM-1 was also shown to be frequently distributed to endothelial junctions both in vitro and in vivo. Cytokines like TNF-alpha stimulate MAdCAM-1 in high endothelium via TK, p38, p42/22 MAPKs, and NF-kappa B/PARP. MAdCAM-1 expression requires NF-kappa B translocation through both direct p42/44 and indirect p38 MAPK pathways in high endothelial cells.