Inhibition of ASM activity ameliorates DSS-induced colitis in mice.

Acid sphingomyelinase (ASM) is a membrane lipid hydrolase, acting to generate ceramide and regulate cell functions and inflammatory responses.The roles of ASM in mediating T cell functions are postulated whereas its function in regulation of macrophages remains uncertain. The study was performed to explore ASM activity in control of macrophage functions. RAW 264.7 cells were pretreated with desipramine, an ASM inhibitor, prior to LPS challenge in vitro. LPS initiated ASM activity in RAW 264.7 cells. Conversely, inhibition of ASM activity by desipramine diminished LPS induced ASM activities and TNF production of RAW 264.7 cells. The DSS colitis in mice was induced, and desipramine was administered to the mice two days post induction of colitis. Murine colitis was characterized by elevation of ASM activities in colon tissues. Desipramine administration overrode ASM activities in colon, and ameliorated DSS-induced colitis evidenced with the reduced disease activities and the decreased cytokine levels. Together, our data show a crucial role of ASM activity in regulation of macrophage functions and responses, and suggest that ASM represents a novel therapeutic approach for the management of immune diseases.

Inhibition of NADPH oxidase activities ameliorates DSS-induced colitis.

NADPH oxidases (NOX) act to generate reactive oxygen species (ROS) and exhibit microbicidal bioactivity, whereas their roles in mediating immune responses of inflammation in intestine remain to be further elucidated. The study was performed to explore the effects of NOX activity on regulation of macrophage functions. Macrophage responses were induced by lipopolysaccharides (LPS) in RAW 264.7 cells (in vitro) or dextran sulfate sodium (DSS) in BALB/c mice (in vivo) respectively. LPS induced NOX2 expression and initiated NOX activities in RAW 264.7 cells. Conversely, inhibition of NOX activity by DPI and VAS2870 diminished LPS induced NOX activities and the downstream signaling in RAW 264.7 cells. Murine colitis was characterized by macrophage accumulation and elevation of NOX activities in colon tissues. DPI and VAS2870 administration overrode NOX activities and ROS productions in colon tissues, and ameliorated DSS-induced colitis evidenced with the reduced disease activities and the decreased cytokine levels. Intriguingly, NOX2 expression levels were elevated in colon tissues of patients with active inflammatory bowel disease. Together, our data show a crucial role of NOX activity in regulation of macrophage functions and responses, and suggest that NOX represents a novel therapeutic approach for the management of immune diseases.

Advances in treatment of ulcerative colitis with herbs: from bench to bedside.

Ulcerative colitis (UC), an idiopathic inflammatory disorder in the colon, has become a clinical challenge, owing to the increasing incidence and poor prognosis. The conventional treatments for UC including aminosalicylates, corticosteroids, and immunosuppressants, induce remission in only half of patients. Meanwhile, the treatments often come with serious side effects which can be life-threatening. Herbal medicine, one of the most common traditional Chinese medicine modalities, has been introduced for centuries into clinical treatment of many human diseases such as infections and functional disorders. Recently, the potential effectiveness of herbs has been suggested as the treatment of UC, as shown by a variety of clinical trials and experimental studies. The herbs reported in the literature include aloe vera gel, butyrate, tormentil extracts, wheat grass juice, and curcumin. In the review, bioactivity of the herbs and their involvement in UC treatment are discussed.

Osteopontin knockdown suppresses the growth and angiogenesis of colon cancer cells.

AIM: To investigate the effects of osteopontin (OPN) gene expression knockdown on colon cancer Lovo cells in vitro. METHODS: Four candidate small interfering RNA (siRNA) constructs targeting the OPN gene and a scrambled control sequence (NC-siRNA) were synthesized and inserted into a pGPU6/GFP/Neo expression vector. After confirmation by restriction enzyme digestion and DNA sequencing, the recombinant plasmids were subsequently transfected into a human colon cancer cell line (Lovo) using a liposome transfection method. Stably transfected cells were maintained with G418 selection and referred to as Lovo-OPN-1, -2, -3, -4, and Lovo-NC cells. Knockdown efficiency of each of the four siRNA constructs was determined by real-time reverse transcription polymerase chain reaction assays and western blotting, and the construct with the most effective silencing was used for subsequent experiments. Cell proliferation, adhesion, and Matrigel invasion assays were performed to analyze the effects of OPN knockdown in stably transfected Lovo cells. The levels of four angiogenic factors, namely vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, MMP-9 and urokinase plasminogen activator were detected by enzyme-linked immunosorbent assays (ELISA). RESULTS: Recombinant vectors containing OPN-specific and scrambled siRNA sequences were successfully constructed and stably transfected into Lovo cells. Compared with the control Lovo and Lovo-NC cells, the levels of OPN mRNA and protein expression in Lovo-OPN-1, -2, -3, and -4 were significantly reduced (all P < 0.05), with the most efficient reduction observed in Lovo-OPN-4 cells (P < 0.05). Relative to untransfected Lovo cells, OPN mRNA expression levels in Lovo-NC and Lovo-OPN-4 cells were 1.008 ± 0.067 and 0.160 ± 0.023, respectively. The relative OPN protein expression levels in Lovo, Lovo-NC, and Lovo-OPN-4 cells were 3.024 ± 0.211, 2.974 ± 0.630, and 0.121 ± 0.008, respectively. Moreover, transfection with the scrambled sequence had no effect on the expression of OPN. After 24, 48, 72, and 96 h of cultivation, absorption values at 450 nm to assess proliferation of Lovo-OPN-4 cells were 0.210 ± 0.017, 0.247 ± 0.024, 0.314 ± 0.037, and 0.359 ± 0.043, respectively, which were significantly lower than those of Lovo (0.244 ± 0.031, 0.313 ± 0.024, 0.513 ± 0.048 and 0.783 ± 0.051) and Lovo-NC cells (0.241 ± 0.029, 0.309 ± 0.022, 0.563 ± 0.023, and 0.735 ± 0.067) (all P < 0.05). The absorption values at 595 nm, which were measured in a cell adhesion assay, showed that adhesion of Lovo-OPN-4 cells (0.215 ± 0.036) was significantly decreased compared to Lovo (0.490 ± 0.037) and Lovo-NC cells (0.462 ± 0.043) (P < 0.05). The number of invasive Lovo-OPN-4 cells (16.1 ± 1.9) was also significantly decreased compared to Lovo (49.9 ± 5.4) and Lovo-NC cells (48.8 ± 4.5) (P < 0.05). ELISA assays showed significant reductions in Lovo-OPN-4 cells compared to Lovo and Lovo-NC cells with regard to the expression of VEGF (1687.85 ± 167.84 ng/L vs 2348.54 ± 143.80 ng/L and 2284.39 ± 138.62 ng/L, respectively), MMP-2 (2966.07 ± 177.36 µg/L vs 4084.74 ± 349.54 µg/L and 4011.41 ± 424.48 µg/L, respectively), MMP-9 (3782.89 ± 300.64 µg/L vs 5062.90 ± 303.02 µg/L and 4986.38 ± 300.75 µg/L, respectively) and uPA (1152.69 ± 120.79 µg/L vs 1380.90 ± 147.25 µg/L and 1449.80 ± 189.92 µg/L, respectively) (all P < 0.05). CONCLUSION: Knockdown of OPN gene expression suppresses colon cancer cell growth, adherence, invasion, and expression of angiogenic factors.

[Effect of Helicobacter pylori-encoded CagA on biological behavior of gastric adenocarcinoma cells in vitro].

OBJECTIVE: To investigate the effect of Helicobacter pylori-encoded CagA on biological behavior of gastric adenocarcinoma AGS cells. METHODS: With experiment-control system of the wild-type CagA positive strain and isogenic CagA negative mutant strain of Helicobacter pyroli (Hp) were used as control and experimental groups, respectively. The cell contact, migration and invasion were examined by light and electron microscopy and invasion assay. RESULTS: The AGS cells infected by Hp strain with positive wild-type CagA showed more severely changed tight junction, wider intercellular space, loss of cell contacts, and higher migrating and invasive ability. CONCLUSION: Hp CagA may lead to loss of cell contacting and higher migrating and invading ability of gastic cells, and accelerates the malignant progress of tumor.

Basic research on inflammatory bowel disease in China.

OBJECTIVE: Since the etiology and the pathogenesis of inflammatory bowel disease (IBD) are still not well known, research on IBD often focuses on these topics. Investigative science papers about IBD in Chinese medical journals from 1989 to 2003 were viewed to understand the progress of basic IBD research in China. MATERIALS AND METHODS: The basic science investigative papers about IBD from 1989 to 2003 in Chinese periodicals (VIP and CMCC) were reviewed and analyzed; the key words used were as follows: inflammatory bowel disease, ulcerative colitis, Crohn's disease, basic science investigation, and literature review. RESULTS: There were 3454 articles about IBD published in Chinese medical journals from 1989 to 2003, and during these 15 years, 508 papers focused on basic scientific investigations. There were 463 papers investigating the pathogenesis of IBD, 287 papers on immunological mechanisms, and 176 papers about other mechanisms. There were 142 papers investigating the mechanisms of Chinese traditional medicine on IBD from 1989 to 2003, which included 117 papers related to animal experiments and 25 papers related to clinical studies. CONCLUSIONS: There have been relatively few investigative scientific papers on IBD published in Chinese medical journals. However, the study of IBD has been emphasized in China. Research on the immunological mechanisms of IBD has been predominant. Furthermore, a large number of the research papers were about the mechanisms and effects of Chinese traditional medicine on IBD.

Diallyl trisulfide inhibits tumor necrosis factor-alpha expression in inflammed mucosa of ulcerative colitis.

The present study aimed to investigate the effect of diallyl trisulfide (DATS) on tumor necrosis factor (TNF)-alpha expression in inflammed mucosa of ulcerative colitis and its possible mechanism. Colonic biopsies from ulcerative colitis were treated with 0, 1, 5, and 10 microM DATS for 24 hr. Lactate dehydrogenase (LDH) activities and concentrations of TNF-alpha in supernatants were measured. mRNA expressions of TNF-alpha in biopsies were analyzed by RT-PCR. The expression of NF-kappaB P65 in tissues was studied by immunohistochemistry. Concentrations of TNF-alpha in supernatants of biopsies treated with 5 and 10 microM DATS were lower than those of untreated biopsies. There were fewer lamina propria mononuclear cells whose NF-kappaB P65 expression in nuclei was positive, and less mRNA expression of TNF-alpha in biopsies treated with 10 microM DATS than in untreated biopsies. There were no differences in LDH activities in supernatants between tissues treated with DATS and untreated tissues. DATS could downregulate TNF-alpha production and inhibit NF-kappaB activation in lamina propria mononuclear cells of inflammed mucosa, without any effect on the viability of colonic tissue cells.

[Activation of nuclear factor-kappa B and expression of cytokine in intestinal epithelia stimulated by TNF-alpha].

OBJECTIVE: To investigate the effect of nuclear factor-kappa B activation on proinflammatory cytokine expression in intestinal epithelia when intestinal epithelia are in inflammatory condition. METHODS: Colonic adenocarcinoma HT29 cells were cultured in wells and TNF-alpha (10 ng/ml) was added into half of the wells. The supernatants were collected and measured for IL-8 after 3 hours, nuclear factor-kappaB (NF-kappaB) P65 and IL-8 mRNA were also examined by Western blotting and RT-PCR respectively. RESULTS: It was found that in the condition of no stimuli, there is little IL-8 mRNA expression of HT29 cells, P65 is seldom in HT29 cells' nuclei, and the concentration of IL-8 in supernatant is just 172 ng/L. However, after being stimulated by TNF-alpha, a lot of P65 expression in nuclei and a large number of IL-8 mRNA expression of HT29 cells are shown and the concentration of IL-8 in supernatant (639 ng/L) is significantly higher than that of control (P<0.01). CONCLUSION: The activation of nuclear factor-kappa B modulates the expression of some proinflammatory cytokine in intestinal epithelia, and regulates epithelia function in inflammatory reaction.

Imrecoxib: a novel and selective cyclooxygenase 2 inhibitor with anti-inflammatory effect.

AIM: To investigate the inhibitory effect of imrecoxib, a synthetic compound of completely new structure, on cyclooxygenase 1 (COX-1) and 2 (COX-2) and its anti-inflammatory effect in vivo. METHODS: The inhibitory effects of imrecoxib on cyclooxygenase 1 and 2 were studied using whole cell assay with murine peritoneal macrophages induced by calcimycin and LPS. The inhibitory effects of imrecoxib on mRNA level of COX-1 and COX-2 in human macrophage cell line U937 were detected by reverse transcription polymerase chain reaction (RT-PCR) analysis. Effects of imrecoxib on acute and chronic inflammation were evaluated in rat carrageenan induced edema model and rat adjuvant-induced arthritis model, respectively. RESULTS: Imrecoxib was found to inhibit COX-1 and COX-2 with IC50 value of 115+/-28 nmol/L and 18+/-4 nmol/L, respectively. Imrecoxib was shown to selectively and dose-dependently inhibit COX-2 mRNA level. Imrecoxib effectively inhibited carrageenan-induced acute inflammation at the doses of 5, 10, and 20 mg/kg i.g. and adjuvant-induced chronic inflammation at the doses of 10 and 20 mg/kg/d i.g. CONCLUSION: Imrecoxib is a novel and moderately selective COX-2 inhibitor that possesses anti-inflammatory effect by inhibition of COX-2 mRNA expression.

Probiotics inhibit TNF-alpha-induced interleukin-8 secretion of HT29 cells.

AIM: To study the effect of probiotics on interleukin-8 secretion in intestinal epithelia when stimulated by proinflammatory cytokines. METHODS: Colonic adenocarcinoma HT29 cells were cultured and divided into four groups: control, TNF-alpha (group T in short), bifidobacterium (group B), lactobacillus (group L). B. Longum and L. bulgaricus were suspended in culture medium with a concentration of 1 x 10(8) cfu/ml and added into 24 wells respectively. One hour later TNF-alpha (10 ng/ml) was added into each well of groups T, B, L. The supernatants were collected and measured for IL-8 after 3 hours, nuclear factor-kappaB (NF-kappaB) p65 was also examined by Western blotting. RESULTS: There was less interleukin-8 secretion in HT29 cells when preincubated with B. Longum or L. bulgaricus compared with group T. Less p65 appeared in nuclei in groups B and L compared with group T, as detected by Western blot. CONCLUSION: Probiotics can suppress interleukin-8 secretion in intestinal epithelia when stimulated by proinflammatory cytokines, which is most likely mediated by NF-kappaB.

Inhibitory effect of 3,4-diaryl-3-pyrrolin-2-one derivatives on cyclooxygenase 1 and 2 in murine peritoneal macrophages.

AIM: To develop a whole-cell assay based on murine peritoneal macrophages and evaluate the inhibitory effect of candidate compounds on cyclooxygenase-1 (COX-1) and COX-2. METHODS: Macrophages were stimulated with calcimycin or lipopolysaccharide (LPS) for various periods. Their abilities to convert endogenous arachidonic acid to 6-keto-PGF1alpha or PGE2 were examined by radioimmunoassay (RIA). RNA level of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and COX-1/2 was detected by reverse transcription polymerase chain reaction (RT-PCR) using specific primers. RESULTS: Rofecoxib selectively inhibited LPS-induced, COX-2-derived PGE2 synthesis with an IC50 value of (4.7+/-0.5) nmol/L compared with maximum inhibitory ratio of 17.3 % for the inhibition of calcimycin induced, COX-1-derived 6-keto-PGF1alpha synthesis. Indomethacin exhibited dual inhibitory effects on COX-1 and COX-2 with IC50 of (4.7+/-1.1) nmol/L and (7.1+/-1.2) nmol/L, respectively. Two series of 17 compounds were tested. Most of compounds in series II showed comparable inhibitory activities to rofecoxib on COX-2. The relative position of the sulfonylphenyl group to the lactam carbonyl group has important effects on COX-2 inhibitory activity. CONCLUSION: The established whole cell assay is appropriate for drug-design oriented in vitro assay. 3,4-Diaryl-3-pyrrolin-2-one derivatives were proved to be prospective new type of COX-2 selective inhibitors.