Role of tumor necrosis factor receptor 2 (TNFR2) in colonic epithelial hyperplasia and chronic intestinal inflammation in mice.

BACKGROUND & AIMS: Tumor necrosis factor (TNF) induces multiple effects including cell proliferation and death by ligation with TNF receptor type II (TNFR2). We studied the role of TNFR2 in chronic inflammation-induced colonic epithelial alteration. METHODS: TNFR2 expression in colonic epithelial cells (CECs) was assessed by ribonuclease protection assay (RPA) and immunohistochemistry (IHC) in patients with inflammatory bowel disease (IBD) and murine colitis models. TNFR2 expression was also analyzed using COLO205 cells. The role of TNFR2 in colonic epithelial homeostasis was examined by generating interleukin 6-deficient TCR alpha KO (alpha IL-6DKO) or TNFR2-deficient TCR alpha (alpha TNFR2DKO) mice. RESULTS: TNFR2 expression was up-regulated in CEC in both human ulcerative colitis and Crohn's disease. In vitro studies showed that TNFR2 expression was up-regulated by a cooperative effect of key proinflammatory cytokines. By RPA, the increased expression of TNFR2 was detectable in TCR alpha KO mice with colitis compared with TCR alpha KO mice without colitis or wild-type mice. In alpha IL-6DKO mice, TNFR2 expression, proliferation, and nuclear factor kappa B activation of CECs were markedly reduced compared with TCR alpha KO mice. alpha TNFR2 mice also showed significantly less colonic epithelial proliferation compared with TCR alpha KO mice. CONCLUSIONS: Expression of TNFR2 is consistently increased on CECs in both murine colitis models as well as patients with IBD. TNFR2 may play an important role in colonic inflammation-associated alteration in the intestinal epithelium.  

Tumor metastasis and the reciprocal regulation of heparanase gene expression by nuclear factor kappa B in human gastric carcinoma tissue

AIM: To investigate whether NF-kB is activated in human gastric carcinoma tissues and, if so, to study whether there is any correlation between NF-kB activity and heparanase expression in gastric carcinoma. METHODS: NF-kB activation was assayed by immunohistochemical staining in formalin-fixed, paraffin-embedded specimens from 45 gastric carcinoma patients. Electrophoretic mobility shift assay (EMSA) method was used for nuclear protein from these fresh tissue specimens. Heparanase gene expression was quantified using quantitative RT-PCR. RESULTS: The nuclear translocation of RelA (marker of NF-kB activation) was significantly higher in tumor cells compared to adjacent and normal epithelial cells [(41.3±3.52)% vs (0.38±0.22) %, t=10.993, P= 0.000<0.05; (41.3±3.52)% vs(0±0.31)%, t=11.484, P= 0.000<0.05]. NF-kB activation was correlated with tumor invasion-related clinicopathological features such as lymphatic invasion, pathological stage, and depth of invasion (Z= 2.148, P= 0.032<0.05; t = 8.758, P= 0.033<0.05; t = 18.531, P = 0.006<0.05). NF-KB activation was significantly correlated with expression of heparanase gene (r= 0.194, P=0.046<0.05). CONCLUSION: NF-KB RelA (p65) activation was related with increased heparanase gene expression and correlated with poor clinicopathological characteristics in gastric cancers. This suggests NF-kB as a major controller of the metastatic phenotype through its reciprocal regulation of some metastasis-related genes.  

苦瓜蛋白对BALB/C小鼠柯萨奇B3病毒性心肌炎核因子κB的调节作用

为探讨苦瓜蛋白对BALB／C小鼠柯萨奇B3病毒性心肌炎的治疗作用机制，以核因子κB为对象，来观察苦瓜蛋白的调节作用。从苦瓜果肉中提取苦瓜蛋白后，将动物分为5组：病毒对照组、正常对照组、药物对照组、高剂量治疗组、低剂量治疗组，分别在实验的第0d,3d,7d,14d和第21d处死动物，提取核蛋白，在用BCA方法进行蛋白定量后作凝胶滞留分析（EMSA），测定核因子κB的活性，并进行比较分析。结果发现：（1）病毒对照组在第21天时仍然有一定量的核因子κB活化，且其活化程度明显高于正常对照组；（2）高、低剂量的苦瓜蛋白对核因子κB表现出不同程度的抑制作用，其中高剂量组核因子κB几乎看不到活化，低剂量组比病毒对照组核因子κB活化程度明显降低；（3）正常对照组和药物对照组核因子κB只有低水平活化。结果提示，苦瓜蛋白对病毒性心肌炎的治疗作用可能与其降低核因子κB的活性有关。  

糖尿病肾病小鼠肾组织基质金属蛋白酶9的表达及其细胞内信号传导机制的探讨

目的　观察Kkay小鼠糖尿病肾病(DN)时肾脏基质金属蛋白酶9(MMP-9) 的表达,并探讨其细胞内信号传导机制。　方法　Kkay糖尿病小鼠(KA)组和非糖尿病小鼠(KB)组各8 只,以PAS染色、免疫组化和逆转录聚合酶链反应(RT PCR)观察肾脏病变、MMP-9 表达水平。经糖基化终末产物(AGEs)作用于脐静脉内皮细胞(HUVECs)后,分别以RT PCR 和流式细胞技术检测MMP-9表达;以凝胶阻滞电泳(EMSA)检测核转录因子κB(NF-κB)激活情况。　结果　KA组出现明显DN病变,其肾小球硬化指数(GI)明显高于KB组(P<0.05);KA组肾小球MMP 9阳性着色面积(11 14%)高于KB组(5 68%)(P<0.01),MMP-9 mRNA表达水平有类似变化。AGEs使HU-VECs MMP-9表达增强,并伴有NF-κB激活。抑制NF-κB活性可降低MMP-9表达。　结论　Kkay小鼠DN伴有MMP-9表达增高,推测MMP-9在DN发生发展中起一定作用;AGEs可能是通过激活NF κB使内皮MMP-9表达增强的。  

Up-regulation of intestinal nuclear factor kappa B and intercellular adhesion molecule-1 following traumatic brain injury in rats

AIM: Nuclear factor kappa B (NF-κB) regulates a large number of genes involved in the inflammatory response to critical illnesses, but it is not known if and how NF-KB is activated and intercellular adhesion molecule-1 (ICAM-1) expressed in the gut following traumatic brain injury (TBI). The aim of current study was to investigate the temporal pattern of intestinal NF-κB activation and ICAM-1 expression following TBI. METHODS: Male Wistar rats were randomly divided into six groups (6 rats in each group) including controls with sham operation and TBI groups at hours 3, 12, 24, and 72, and on d 7. Parietal brain contusion was adopted using weight-dropping method. All rats were decapitated at corresponding time point and mid-jejunum samples were taken. NF-KB binding activity in jejunal tissue was measured using EMSA. Immunohistochemistry was used for detection of ICAM-1 expression in jejunal samples. RESULTS: There was a very low NF-κB binding activity and little ICAM-1 expression in the gut of control rats after sham surgery. NF-KB binding activity in jejunum significantly increased by 160% at 3 h following TBI (P<0.05 vs control), peaked at 72 h (500% increase) and remained elevated on d 7 post-injury by 390% increase. Compared to controls, ICAM-1 was significantly up-regulated on the endothelia of microvessels in villous interstitium and lamina propria by 24 h following TBI and maximally expressed at 72 h post-injury (P<0.001). The endothelial ICAM-1 immunoreactivity in jejunal mucosa still remained strong on d 7 post-injury. The peak of NF-κB activation and endothelial ICAM-1 expression coincided in time with the period during which secondary mucosal injury of the gut was also at their culmination following TBI. CONCLUSION: TBI could induce an immediate and persistent up-regulation of NF-κB activity and subsequent up-regulation of ICAM-1 expression in the intestine. Inflammatory response mediated by increased NF-κB activation and ICAM-1 expression may play an important role in the pathogenesis of acute gut mucosal injury following TBI.  

Interleukin-6 contributes to Mcl-1 up-regulation and TRAIL resistance via an Akt-signaling pathway in cholangiocarcinoma cells

BACKGROUND & AIMS: Cholangiocarcinomas often arise within a background of chronic inflammation suggesting that inflammation imparts survival signals to this cancer. Previous studies have also shown that the inflammatory cytokine interleukin (interleukin [IL]-6) contributes to survival signals in an autocrine fashion and that myeloid cell leukemia-1 (Mcl-1), an antiapoptotic member of the B-cell leukemia-2 family, is an important participant in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance in this neoplasm. The present study evaluated the possibility that IL-6 signaling contributes to Mcl-1 up-regulation in cholangiocarcinoma. METHODS: Protein kinase B (Akt) and Mcl-1 expression in human tissue was assessed by immunohistochemistry. The relationship between IL-6 signaling, Akt activity, and Mcl-1 expression was examined in cell lines. RESULTS: Immunohistochemistry showed that the serine/threonine kinase Akt and Mcl-1 are strongly expressed in the preneoplastic bile duct inflammatory disease primary sclerosing cholangitis and in human cholangiocarcinoma specimens. Immunoblotting showed that Akt is expressed and constitutively phosphorylated in 3 human cholangiocarcinoma lines. Further analysis showed that treatment with anti-IL-6-neutralizing antiserum led to reduced Akt phosphorylation, diminished Mcl-1 expression, and enhanced TRAIL sensitivity. Likewise, the Akt inhibitor A443654.3 led to diminished signaling through the Akt pathway, decreased Mcl-1 expression, and enhanced TRAIL-mediated apoptosis. CONCLUSIONS: These findings not only show that an autocrine IL-6/Akt signaling pathway enhances Mcl-1 expression in cholangiocarcinoma but also suggest a strategy for overcoming the resulting apoptosis resistance.