Nonghua Lu

All-trans retinoic acid down-regulates inflammatory responses by shifting the Treg/Th17 profile in human ulcerative and murine colitis

IBD is characterized by uncontrolled immune responses in inflamed mucosa, with dominance of IL‐17‐producing cells and deficiency of Treg cells. The aim of this study was to explore the effect and mechanisms of RA, the ligand of RARα, on immune responses in human and murine colitis. Colonic biopsies from patients with UC were cultured and treated with RA as the agonist of RARα or LE135 as the antagonist of RARα. Expressions of IL‐17 and FOXP3 were detected by immunohistochemistry. Murine colitis was induced by intrarectal administration with TNBS at Day 1. Mice were then i.p.‐treated with RA or LE135 daily for 7 days. Cytokine levels in the cultures of mouse LPMCs were measured. Expressions of FOXP3 and IL‐17 in colon tissues or MLN were detected by immunohistological analysis. Body weight and colon inflammation were evaluated. RA treatment up‐regulated FOXP3 expression and down‐regulated IL‐17 expression in colon biopsies of patients and in colon tissues and MLN of mice with colitis compared with controls. LPMCs from RA‐treated mice produced lower levels of proinflammatory cytokines (TNF‐α, IL‐1β, IL‐17) but more regulatory cytokines (IL‐10, TGF‐β) compared with that of untreated mice. LE135 showed the opposite effect of RA. Furthermore, RA ameliorated TNBS‐induced colitis in a dose‐dependent manner, as seen by improved body weight and colon inflammation. RA down‐regulates colon inflammatory responses in patients with IBD in vitro and in murine colitis in vivo, representing a potential therapeutic approach in IBD treatment.

The Effect of the Cholinergic Anti-Inflammatory Pathway on Experimental Colitis

Inflammatory bowel diseases (IBD) are characterized by proinflammatory cytokines, tissue damage and loss of neuron in inflamed mucosa, which implies the cholinergic anti‐inflammatory pathway may be destroyed during the process of inflammatory response. In the study, we identified the effect of cholinergic agonist as anabaseine (AN) and nicotinic receptor antagonist as chlorisondamine diiodide (CHD) on trinitrobenzene sulfonic acid (TNBS)‐induced colitis, to investigate the potential therapeutic effect of the cholinergic anti‐inflammatory pathway on IBD. Experimental colitis was induced by TNBS at day 1, 10u2003μg AN or 1.5u2003μg CHD was injected i.p. to mouse right after the induction of colitis, and repeated on interval day till the mice were sacrificed at day 8. Colonic inflammation was examined by histological analysis, myeloperoxidase (MPO) activity, and the production of tumour necrosis factor (TNF)‐α in tissue. Lamina propria mononuclear cells (LPMC) were isolated, and NF‐κB activation was detected by western blot. The mice with colitis treated by AN showed less tissue damage, less MPO activity, less TNF‐α production in colon, and inhibited NF‐κB activation in LPMC, compared with those mice with colitis untreated, whereas the mice with colitis treated by CHD showed the worst tissue damage, the highest MPO activity, the highest TNF‐α level, and enlarged NF‐κB activation in LPMC. Agonist of the cholinergic anti‐inflammatory pathway inhibits colonic inflammatory response by downregulating the production of TNF‐α, and inhibiting NF‐κB activation, which suggests that modulating the cholinergic anti‐inflammatory pathway may be a new potential management for IBD.

Tanshinone IIA Ameliorates Trinitrobenzene Sulfonic Acid (TNBS)-Induced Murine Colitis

Inflammatory bowel diseases are characterized by proinflammatory cytokines, oxidative stress, and tissue damage. Recently, tanshinone had been shown to act as an antioxidant, and to have anti-inflammatory bioactivity. The study was carried out to investigate the effect of tanshinone IIA on the inflammatory response of experimental colitis. Murine colitis was induced by trinitrobenzene sulfonic acid (TNBS). Ten or 20xa0mg tanshinone IIA was administrated to mice 4xa0h before the induction of colitis, and repeated daily until the mice were sacrificed. Colonic inflammation was examined by histological analysis, myeloperoxidase (MPO) activity, and the production of proinflammatory cytokines in colonic tissue. Activation of nuclear factor-kappa B was identified by western blot and immunohistochemistry, and oxidative stress was shown by glutathione (GSH) level in tissue. The mice with colitis treated by tanshinone IIA showed less tissue damage, lower MPO activity, less production of TNF-α and IL-1β, a higher level of GSH in colonic tissue, and downregulated activation of nuclear factor-kappa B in lamina propria mononuclear cells, compared with those of the untreated colitis group. Our data indicates that tanshinone IIA inhibits inflammatory response of colitis by downregulating the production of proinflammatory cytokines, and attenuating oxidative stress, which suggests that tanshinone IIA may be a new potential management for inflammatory bowel diseases.

All-trans retinoic acid attenuates experimental colitis through inhibition of NF-κB signaling

Inflammatory bowel disease (IBD) is characterized by excessive innate immune cell activation, which is responsible for tissue damage and induction of adaptive immune responses. All-trans retinoic acid (ATRA), the ligand of retinoic acid receptors (RAR), has been previously shown to regulate adaptive immune responses and restore Th17/Treg balance, while its role in regulation of innate immune cell function such as macrophages remains to be elucidated. The study was performed to explore the effect of ATRA on regulation of innate immune responses during dextran sulfate sodium (DSS) induced murine colitis. The mice with DSS colitis were administered with vehicle, ATRA, or LE135. Colitis was evaluated by clinical symptoms, tissue myeloperoxidase (MPO) activity, and the expressions of CD68 and nuclear factor (NF) κB p65, and tumor necrosis factor (TNF) level in inflamed colon. RAW 264.7 cells were pretreated with vehicle, ATRA, or LE135, followed by LPS challenge in vitro. ATRA administration ameliorates DSS-induced colitis evidenced with decreased TNF level and CD68 expression, while LE135 leads to exacerbation of colitis. ATRA treatment in vitro dampens LPS induced NF-κB activation and TNF production of RAW 264.7 cells. Together, our data show a crucial role of ATRA in the progress of acute colitis through inhibiting NF-κB activation, and suggest that ATRA represents a novel therapeutic approach for the management of IBD.

Seasonality in Flares and Months of Births of Patients with Ulcerative Colitis in a Chinese Population

Background and Aims Reports on seasonality in flares or months of births of inflammatory bowel disease patients have been inconsistent, but little data are available in a Chinese population. The aim of this study was to determine whether symptom flares and births of ulcerative colitis (UC) patients follow a seasonal pattern. Methods Patients with a diagnosis of UC established between January 1990 and December 2007 were investigated according to the occurrence of flares of symptoms and months of births. The expected flares or births were calculated on a monthly basis over the study period, taking into consideration the difference in the number of days in the month in each year. Results A total of 409 UC patients were included in the study, and 1030 flares of symptoms were determined. The peak number of flares occurred during the spring and summer, especially in June, while the nadir occurred in the winter, especially in January (χ2(11 df)xa0=xa032.74304, Pxa0<xa00.005). The symptom flares also occurred more frequently in the spring–summer period than in the autumn–winter period (χ2(3 df)xa0=xa022.1269, Pxa0<xa00.001). There was no statistical difference in birth distribution on a monthly or seasonal (spring, summer, autumn, winter) basis. However, the births of UC patients occurred more frequently in the autumn–winter period than in the spring–summer period when the data were merged into these two seasonal components (χ2(1 df)xa0=xa05.255607, Pxa0<xa00.025). Conclusions The data indicate that the symptom flares of UC occurred more frequently in the spring and summer, while the births of UC patients occurred more often in the autumn and winter. Environmental recurring factors may be associated with the symptom flares of UC, and these factors during pregnancy or postpartum may be associated with susceptibility to UC later in life.

Effect of Helicobacter pylori eradication on oncogenes and cell proliferation.

Backgroundu2002 Helicobacter pylori , the main cause of chronic gastritis, is a class 1 gastric carcinogen. However, it remains unclear whether H. pylori affects molecular alterations in chronic gastritis. Thus, this study was designed to investigate the effect of H. pylori eradication on the expression of human telomerase RNA (hTR), human telomerase reverse transcriptase (hTERT), c‐myc and proliferation nuclear cell antigen (PCNA) in H. pylori associated chronic gastritis.

Helicobacter pylori Infection Activates the Akt-Mdm2-p53 Signaling Pathway in Gastric Epithelial Cells.

Backgrounds and AimsAlthough Helicobacter pylori is widely accepted as a causative factor of many gastric diseases, the signaling pathways affected by H. pylori and subsequent effects on cell apoptosis and proliferation remain unclear. Here, we investigated the molecular mechanisms mediating H. pylori infection in gastric epithelial cells.MethodsTissues from 160 patients with various gastric diseases with or without H. pylori infection were obtained and analyzed by immunohistochemistry for Akt, pAkt, Mdm2, p53, and Bax expression. In vitro, human gastric epithelial cells, GES-1, were incubated with H. pylori culture filtrates. Cell viability was measured by MTT assay. Apoptosis was evaluated by Annexin V/PI double staining followed by flow cytometry, DNA electrophoresis, and comet assay. mRNA and protein expression was assessed by RT-PCR and Western blot analysis.ResultsIn patient tissues, H. pylori infection was associated with significantly elevated levels of pAkt in chronic nonatrophic gastritis (CNAG), Mdm2 in dysplasia, p53 in metaplastic atrophy (MA), and Bax in CNAG and MA. In vitro, H. pylori culture filtrates reduced GES-1 cell viability in a time- and dose-dependent manner, induced G0/G1 arrest, triggered apoptosis, and increased DNA fragmentation. Mdm2 and Bax mRNA expression and pAkt, Mdm2, p53, and Bax protein expression were significantly upregulated when treated with H. pylori culture filtrates. Akt inhibition by LY294002 decreased Mdm2 expression, upregulated p53, and enhanced H. pylori-induced growth inhibition of GES-1 cells.ConclusionsThese findings suggest that Akt–Mdm2–p53 signaling is involved in the molecular response of GES-1 cells to H. pylori infection.

Treatment of inflammatory bowel disease with neural stem cells expressing choline acetyltransferase.

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder, with increasing incidence and prevalence in the last one-half century. IBD patients suffer from autonomic vagal neuropathy and nerve dysfunction, with deficiency of acetylcholine in inflamed mucosa. Recent studies showed that death of enteric neuron in local tissue was induced during the process of IBD, which also played a crucial role in the pathogenesis of disease. Stem cells have been demonstrated a new biological treatment for IBD, therefore, we proposal that neural stem cells expressing choline acetyltransferase may enhance enteric neural cell regeneration, restore acetylcholine production in intestinal mucosa, and thus inhibit immune responses of IBD.

M1671 All-Trans Retinoic Acid Downregulates Inflammatory Responses By Shifting the Treg/TH17 Profile in Human Ulcerative and Murine Colitis

IBD is characterized by uncontrolled immune responses in inflamed mucosa, with dominance of IL-17-producing cells and deficiency of Treg cells. The aim of this study was to explore the effect and mechanisms of RA, the ligand of RAR, on immune responses in human and murine colitis. Colonic biopsies from patients with UC were cultured and treated with RA as the agonist of RAR or LE135 as the antagonist of RAR. Expressions of IL-17 and FOXP3 were detected by immunohistochemistry. Murine colitis was induced by intrarectal administration with TNBS at Day 1. Mice were then i.p.-treated with RA or LE135 daily for 7 days. Cytokine levels in the cultures of mouse LPMCs were measured. Expressions of FOXP3 and IL-17 in colon tissues or MLN were detected by immunohistological analysis. Body weight and colon inflammation were evaluated. RA treatment up-regulated FOXP3 expression and downregulated IL-17 expression in colon biopsies of patients and in colon tissues and MLN of mice with colitis compared with controls. LPMCs from RA-treated mice produced lower levels of proinflammatory cytokines (TNF-, IL-1, IL-17) but more regulatory cytokines (IL-10, TGF-) compared with that of untreated mice. LE135 showed the opposite effect of RA. Furthermore, RA ameliorated TNBS-induced colitis in a dose-dependent manner, as seen by improved body weight and colon inflammation. RA down-regulates colon inflammatory responses in patients with IBD in vitro and in murine colitis in vivo, representing a potential therapeutic approach in IBD treatment. J. Leukoc. Biol. 86: 959–969; 2009.