Low molecular weight heparin (LMWH) exhibits anti-inflammatory properties, but its effect on inflammation in colitis remains unclear. This study aimed to evaluate the therapeutic effects of LMWH on dextran sulfate sodium (DSS)-induced colitis in mice, in which acute colitis progresses to chronic colitis, and to explore the potential mechanism involved in this process. C57BL/6 mice were randomly divided into control, DSS, and DSS plus LMWH groups (n = 18). Disease activity was scored by a disease activity index (DAI). Histological changes were evaluated by hematoxylin and eosin (HE) staining. The mRNA levels of syndecan-1, interleukin (IL)-1β, and IL-10 were determined by quantitative reverse transcription polymerase chain reaction. Protein expression of syndecan-1 was detected by immunohistochemistry. The serum syndecan-1 level was examined by a dot immunobinding assay. LMWH ameliorated the disease activity of colitis induced by DSS administration in mice. Colon destruction with the appearance of crypt damage, goblet cell loss, and a larger ulcer was found on day 12 after DSS administration, which was greatly relieved by the treatment of LMWH. LMWH upregulated syndecan-1 expression in the intestinal mucosa and reduced the serum syndecan-1 level on days 12 and 20 after DSS administration (P<0.05 vs. DSS group). In addition, LMWH significantly decreased the expression of both IL-1β and IL-10 mRNA on days 12 and 20 (P<0.05 vs. DSS group). LMWH has therapeutic effects on colitis by downregulating inflammatory cytokines and inhibiting syndecan-1 shedding in the intestinal mucosa.

BACKGROUND:Syndecan-1(Sdc1) plays important roles in many steps of inflammatory responses. In ulcerative colitis patients, decreased Sdc1 expression was observed and Sdc1 analogue heparin could improve the disease course. A better understanding of how Sdc1 functions in colitis will benefit the disease intervention.AIMS:To evaluate the role of Sdc1 in dextran sulfate sodium (DSS)-induced colitis.METHODS:BALB/c mice were grouped randomly into control, DSS, and heparin+DSS. The DSS group was given 4% DSS orally and heparin+DSS group was given 4% DSS with heparin (enoxaparin) subcutaneously, while the control was given distilled water orally. All mice were killed at day 7. Disease activities, histopathological changes, membrane-bound and free Sdc1 level and mRNA expression of Sdc1, IL-1, and IL-10 in colon mucosa were detected.RESULTS:Significant colitis was observed in the DSS group, but disease activity index and histological score showed significant lower in the heparin+DSS group than those in the DSS group. Compared to the control group, decreased Sdc1 protein expression was detected in colon mucosa of DSS-induced colitis while Sdc1 ectodomain level in serum was much higher. Inhibited Sdc1 ectodomain shedding was detected in the heparin+DSS group compared to the DSS group. RT-PCR demonstrated that both IL-1 and IL-10 expression were up-regulated in DSS-induced colitis while heparin lessened the up-regulation extent.CONCLUSIONS:Sdc1 shedding is activated in DSS-induced colitis and heparin, which mimics Sdc1 functions, relieves colitis severity by inhibiting Sdc1 shedding and down-regulating cytokines expression.

p21-activated kinase 5 (PAK5) is a recently identified member of the group B PAK family. The PAK proteins are effectors of the small GTPase Cdc42 and Rac1 and are known to regulate cell motility and activate cell-survival signaling pathways. Especially, the mitochondrial localization of PAK5 is vital to its effects on apoptosis and cell survival. Previously, we demonstrated that PAK5 expression increased significantly during the malignant progression of colorectal carcinoma (CRC) and that PAK5 promoted CRC metastasis by regulating CRC cell adhesion and migration. In the present study, we aim to investigate the role of PAK5 in camptothecin-induced apoptosis and its potential mechanism of action. Our results showed that overexpression of PAK5 inhibited camptothecin-induced apoptosis by inhibiting the activity of caspase-8 in CRC cells. Accordingly, knockdown of PAK5 in LoVo cells resulted in increased apoptosis. Mechanistically, we found that PAK5 directly phosphorylated Bad on serine 112 and indirectly led to phosphorylation of serine 136 via the Akt pathway. In conclusion, our study revealed previously unappreciated inhibitory role of PAK5 in camptothecin-induced apoptosis, thus suggesting PAK5 as a novel therapeutic target in CRC.

Background: Besides its well-known anticoagulant action, heparin also has anti-inflammatory effect. However, the mechanism responsible for the anti-inflammatory effect is not yet fully elucidated. Aims: To observe the effect of low molecular weight heparin (LMWH) on mRNA and protein expressions of Syndecan-1 (Sdc-1) and mRNA expression of interleukin (IL)-1β in colitis model induced by dextran sulfate sodium (DSS) in mice, and to define the mechanism of its anti-inflammatory effect. Methods: Fifty-four C57BL/6 mice were divided into normal control group, model group and treatment group. Mice were fed with 3% DSS solution for 5 days followed by distilled water for 2 weeks to induce the colitis model which progressed from acute to chronic inflammation. Mice in treatment group were given LMWH by subcutaneous injection. The mice were killed on 5th, 12th and 19th day, and the colonic histopathological score was evaluated. The mRNA expressions of Sdc-1 and IL-1β in colonic mucosa were assessed by RT-PCR. The protein expression of Sdc-1 in colonic mucosa was evaluated by immunohistochemistry. Results: Compared with the normal control group, the colonic histopathological score and mRNA expression of IL-1β at various time points were significantly increased (P<0.05), while mRNA and protein expressions of Sdc-1 were significantly decreased (P<0.05) in model group. After treatment with LMWH, all the above-mentioned indices were significantly ameliorated. Conclusions: In the process of acute colitis progressing to chronic stage induced by DSS in mice, LMWH has an anti-inflammatory effect, which may be due to the down-regulation of expression of IL-1β. The administration of LMWH can reduce intestinal mucosal injury, and may replace the lost Sdc-1 from cell surface, thus speeding up the restoration process and promoting healing of colitis.

目的:探讨Syndecan-1在葡聚糖硫酸钠(DSS)诱导的小鼠结肠炎中的表达及其在肠道炎症中的作用.方法:54只C57BL/6小鼠随机分为正常对照组和模型组,每组27只.模型组自由饮用3%DSS溶液,5 d后改饮用蒸馏水2、vk,建立急性结肠炎慢性化模型.正常对照组饮用蒸馏水19 d.于实验第5、12、19天分别处死2组各9只小鼠.HE染色评价小鼠结肠组织学改变:RT-PCR检测小鼠肠黏膜Sdc-1 mRNA及IL-8mRNA表达:免疫组织化学检测小鼠肠黏膜Sdc-1蛋白的表达.结果:第5、12、19天模型组小鼠结肠组织学评分均高于对照组(2.17±1.03、2.60±1.73、1.18±0.75 vs 0.04±0.13,均p<0.05);模型组小鼠肠黏膜Sdc-l mRNA表达水平均明显低于对照组(1.58±0.13、1.39±0.17、1.78±0.08 vs2.12±0.03,均P<0.05);模型组小鼠肠黏膜细胞表面Sdc-1蛋白水平均明显低于对照组(1.59±0.12、1.43±0.12、1.81±0.10 vs 2.20±0.04.均P<0.01);模型组小鼠结肠黏膜IL-8 mRNA表达评分均高于对照组(1.20±0.15、1.53±0.05、1.65±0.04 VS 1.02±0.08,均P<0.01).结论:小鼠结肠炎症的严重程度可能与肠黏膜Sdc-1 mRNA及蛋白表达水平减低均有关,而肠黏膜Sdc-1mRNA及蛋白表达水平减低可能与肠黏膜IL-8水平增高有关.

OBJECTIVE:To explore the effect of syndecan-1 (Sdc-1) in the pathogenesis of colitis. METHODS:Thirty BALB/c mice were forced to drink 4% dextran sodium sulphate (DSS) in distilled water as the sole source of drinking fluid for 7 days, distilled water for 10 days, and 4% DSS in distilled water for another 7 days so as to establish colitis models and then were randomly divided into 3 equal groups: model groups 1, 2, and 3 to be killed 8, 18, and 25 days after the DSS drinking respectively to take their colons. Another 10 mice were fed with distilled water as control group and were killed on Day 8. Microscopy was used to evaluate the histological score of the colon. RT-PCR was used to detect the expression of Sdc-1 mRNA and IL-1 mRNA in the colon mucosa. Immunohistochemistry was conducted to detect the Sdc-1 protein level. RESULTS:The histological scores of the 3 model groups were all significantly higher than that of the control group (F = 448.717, P < 0.01) and the score was the highest in the model group 1 and then gradually decreased. There was not significant differences in the Sdc-1 mRNA expression among different groups (F = 0.822, P > 0.05). The levels of Sdc-1 protein of the 3 model groups were all significantly lower than that of the control group (F = 865.586, P < 0.01), and the Sdc-1 protein level was the lowest level in the model group1, and then increased gradually. The expression of IL-1 mRNA of the 3 model groups were all significantly higher than that of the control group (F = 103.833, P < 0.01), and the IL-1 mRNA level was the highest in the model group1 and then decreased gradually. CONCLUSION:The severity of colitis is associated with the reduction of Sdc-1 protein level, but not with the Sdc-1 mRNA level in the colon mucosa. The reduction of Sdc-1 protein level may be associated to increase of IL-1 level.