The interleukin-6 signal transducer, gp130, functioning in immune, hematopoietic, and neural systems]

Functional pleiotropy and redundancy are characteristic features of cytokines. To understand the signaling mechanisms of such cytokines, we have proposed a two-chain interleukin-6 receptor (IL-6-R) model: IL-6 triggers the association of a ligand-binding chain (IL-6-R) and a non-binding signal transducer (gp130) to form a high-affinity receptor complex, causing transmission of the signal by the cytoplasmic portion of gp130. This model would explain the functional redundancy of cytokines if we were to assume that gp130 interacts with several different receptor chains. Here we present data indicating that gp130 functions as a common signal transducer for IL-6, oncostatin M (OM), leukemia inhibitory factor (LIF), and ciliary neurotrophic factor (CNTF). We show that anti-gp130 monoclonal antibodies completely block the biological responses induced by all of these factors. Since LIF functions as a cholinergic differentiation factor in nerve cells as does CNTF, these results suggest that gp130 may also play a role in the neural system.     

gp130胞外区两个片段的克隆与表达及其对IL-6信号转导的影响(英文)

gp130是白细胞介素6(IL-6)受体的β亚基和信号转导子。IL-6介导的信号转导起始于gp130与IL-6和IL-6Rα形成的复合体,但目前还不了解gp130分子中参与复合物形成的部位。为了研究gp130胞外区的结构与功能,我们通过PCR方法构建并克隆表达了其胞外区全长(大片段)及氨基端304个氨基酸残基的片段(小片段),并在杂交瘤细胞系7TD1和肝癌细胞系HepG2中观察其生物学效应。结果发现,含细胞因子结合区的可溶性小片段和大片段都能与膜结合型gp130竞争性结合IL-6和IL-6Rα,拮抗IL-6信号。可见gp130氨基端304个氨基酸残基的片段中存在与IL-6和IL-6Rα作用的部位。     

CD98 expression modulates intestinal homeostasis, inflammation, and colitis-associated cancer in mice

Expression of the transmembrane glycoprotein CD98 (encoded by SLC3A2) is increased in intestinal inflammatory conditions, such as inflammatory bowel disease (IBD), and in various carcinomas, yet its pathogenetic role remains unknown. By generating gain- and loss-of-function mouse models with genetically manipulated CD98 expression specifically in intestinal epithelial cells (IECs), we explored the role of CD98 in intestinal homeostasis, inflammation, and colitis-associated tumorigenesis. IEC-specific CD98 overexpression induced gut homeostatic defects and increased inflammatory responses to DSS-induced colitis, promoting colitis-associated tumorigenesis in mice. Further analysis indicated that the ability of IEC-specific CD98 overexpression to induce tumorigenesis was linked to its capacity to induce barrier dysfunction and to stimulate cell proliferation and production of proinflammatory mediators. To validate these results, we constructed mice carrying conditional floxed Slc3a2 alleles and crossed them with Villin-Cre mice such that CD98 was downregulated only in IECs. These mice exhibited attenuated inflammatory responses and resistance to both DSS-induced colitis and colitis-associated tumorigenesis. Together, our data show that intestinal CD98 expression has a crucial role in controlling homeostatic and innate immune responses in the gut. Modulation of CD98 expression in IECs therefore represents a promising therapeutic strategy for the treatment and prevention of inflammatory intestinal diseases, such as IBD and colitis-associated cancer.     

STAT3 and STAT1 mediate IL-11-dependent and inflammation-associated gastric tumorigenesis in gp130 receptor mutant mice

Deregulated activation of STAT3 is frequently associated with many human hematological and epithelial malignancies, including gastric cancer. While exaggerated STAT3 signaling facilitates an antiapoptotic, proangiogenic, and proproliferative environment for neoplastic cells, the molecular mechanisms leading to STAT3 hyperactivation remain poorly understood. Using the gp130(Y757F/Y757F) mouse model of gastric cancer, which carries a mutated gp130 cytokine receptor signaling subunit that cannot bind the negative regulator of cytokine signaling SOCS3 and is characterized by hyperactivation of the signaling molecules STAT1 and STAT3, we have provided genetic evidence that IL-11 promotes chronic gastric inflammation and associated tumorigenesis. Expression of IL-11 was increased in gastric tumors in gp130(Y757F/Y757F) mice, when compared with unaffected gastric tissue in wild-type mice, while gp130(Y757F/Y757F) mice lacking the IL-11 ligand-binding receptor subunit (IL-11Ralpha) showed normal gastric STAT3 activation and IL-11 expression and failed to develop gastric tumors. Furthermore, reducing STAT3 activity in gp130(Y757F/Y757F) mice, either genetically or by therapeutic administration of STAT3 antisense oligonucleotides, normalized gastric IL-11 expression and alleviated gastric tumor burden. Surprisingly, the genetic reduction of STAT1 expression also reduced gastric tumorigenesis in gp130(Y757F/Y757F) mice and coincided with reduced gastric inflammation and IL-11 expression. Collectively, our data have identified IL-11 as a crucial cytokine promoting chronic gastric inflammation and associated tumorigenesis mediated by excessive activation of STAT3 and STAT1.     

Platelets, inflammation and atherosclerosis

Summary.  An expanding body of evidence continues to build on the role of platelets as initial actors in the development of atherosclerotic lesions. Platelets bind to leukocytes and endothelial cells, and initiate monocyte transformation into macrophages. Platelets internalize oxidized phospholipids and promote foam cell formation. Platelets also recruit progenitor cells to the scene that are able to differentiate into foam cells or endothelial cells depending on conditions. Platelets tip the scales in the initiation, development and total extent of atherosclerotic lesions.     

Vascular lipases, inflammation and atherosclerosis

Members of the lipase family that include lipoprotein lipase, hepatic lipase and endothelial cell lipase play a central role in triglyceride and phospholipid hydrolysis. Because the site of action of these lipases is the endothelium, the endothelium is constantly exposed to products of lipolysis. These lipolysis products could elicit pro- or anti-inflammatory effects in endothelial as well as surrounding cells. These effects could be transient or long-term depending on the nutritional state. While lipolysis is per se anti-atherogenic due to its triglyceride lowering activity, it could also be pro-atherogenic due to prolonged exposure of endothelium to lipolysis products. In addition, lipoprotein lipase expressed in macrophages appears to be pro-atherogenic independent of plasma lipoproteins. In this review we summarize these pro- and anti-inflammatory consequences of lipolysis with respect to atherosclerosis.     

Oncostatin M, leukemia inhibitory factor, and interleukin 6 induce the proliferation of human plasmacytoma cells via the common signal transducer, gp130

We analyzed the stimulatory effect of oncostatin M (OSM), leukemia inhibitory factor (LIF), interleukin 6 (IL-6), IL-11, and the inhibitory effect of anti-IL-6 antibody (Ab), anti-IL-6 receptor monoclonal antibody (mAb), and anti-gp130 mAb on the growth of human plasmacytoma cells freshly isolated from a patient with multiple myeloma. The purified cells showed a plasmacytoid morphology and expressed CD38, CD54, and CD56 antigens but no CD3, CD5, CD10, CD19, CD20, or very late antigen 5. IL-6 receptor (IL-6R) and its signal transducer, gp130, were expressed on their cell surface at a low level. Dose-dependent proliferation of the cells in response to OSM, LIF, and IL-6, but not to IL-11, was observed using [3H]TdR incorporation in vitro. Both anti-IL-6 Ab and anti-IL-6R mAb inhibited the growth of the cells in the presence or absence of exogenous IL-6. These cells release IL-6 but not OSM or LIF into the culture supernatant during short-term culture. Therefore, an autocrine growth mechanism mediated by IL-6, but not by OSM or LIF, was confirmed. Furthermore, anti-gp130 mAb completely inhibited the proliferation of the cells induced by OSM, LIF, as well as IL-6. These data indicate that OSM, LIF, and IL-6 can act as growth factors of human plasmacytoma cells through a common signal transducer, gp130, on their cell surface, and also suggest the potential therapeutic application of anti-gp130 mAb, as well as anti-IL- 6R mAb against myeloma/plasmacytomas.     

动脉粥样硬化炎症的诊断进展

越来越多的证据表明动脉粥样硬化是血管壁的慢性炎症性疾病.因此,能早期通过对血管壁炎症定位的检测对于早期防治动脉粥样硬化具有重要临床意义.本文主要介绍动脉粥样硬化的炎症过程、现有的实验室炎症检测方法及炎症的影像学诊断方法,重点介绍了对比超声在炎症诊断中的重要价值.     

白细胞介素-6受体亚单位gp80和gp130在骨质疏松症中的基因表达(英文)

目的观察骨质疏松症骨髓白细胞介素-6(IL-6)受体(IL-6R)亚单位gp80和gp130基因表达的变化,探讨IL-6R复合系统在雌激素缺乏所致骨质疏松中的作用。方法12周龄雌性SD大鼠20只犤体重(200±20)g犦随机分为骨质疏松组(10只)和空白对照组(10只)。分别于造模后0、12周,测定大鼠骨髓gp80和gp130mRNA水平。结果gp130mRNA水平(pg/μgtotalRNA):术后0、12周空白对照组无明显变化犤(80±3)和(82±4),t=0.85,P>0.05犦,骨质疏松组明显增加犤(80±3)和(290±40),t=6.46,P<0.01犦。gp80mRNA水平(pg/μgtotalRNA):术后0、12周空白对照组无明显变化增加犤(85.4±2.7)和(85.6±2.8),t=0.35,P>0.05犦,骨质疏松组明显增加犤(85.2±2.7)和(210±40),t=6.32,P<0.01犦。结论卵巢切除所致骨质疏松大鼠骨髓IL-6R亚单位gp80和gp130基因表达增加。     

Early atherosclerosis and vascular inflammation in mice with diet‐induced type 2 diabetes

Background Obesity and type 2 diabetes increase the risk of atherosclerosis. It is unknown to what extent this reflects direct effects on the arterial wall or secondary effects of hyperlipidaemia. Materials and methods The effect of obesity and type 2 diabetes on the development of atherosclerosis and inflammation, in the absence or presence of hyperlipidaemia, was assed in wild‐type (n = 36) and human apolipoprotein B (apoB) transgenic mice (n = 27) that were fed normal chow or 60% fat for 12 months. Results Fat‐feeding caused obesity, glucose intolerance and elevated plasma leptin and soluble vascular cell adhesion molecule‐1 (sVCAM‐1) in both wild‐type and apoB transgenic mice. In wild‐type mice, plasma very low‐density lipoprotein cholesterol (VLDL‐C) and low‐density lipoprotein cholesterol (LDL‐C) were unaffected by fat‐feeding. ApoB transgenic mice had mildly elevated plasma LDL‐C (~1 mmol L^?1), which was slightly increased by fat‐feeding. Sixty‐four per cent of fat‐fed wild‐type mice vs. 7% of chow‐fed wild‐type mice had lipid‐staining intimal lesions in the aortic root (P = 0·002). Eighty‐six per cent of fat‐fed apoB transgenic mice had lipid‐staining lesions and the median lesion area was 8·0 times higher than in fat‐fed wild‐type mice (P = 0·001). Intracellular adhesion molecule‐1 staining of the aortic endothelium was most pronounced in the fat‐fed apoB transgenic mice. Conclusions Our findings suggest that diet‐induced type 2 diabetes causes early atherosclerosis in the absence of dyslipidaemia, and that even a moderate level of LDL‐C markedly augments this effect.     

白细胞介素-6/糖蛋白130/转录激活因子3通路在百草枯诱导小鼠急性肺损伤中的作用机制

目的基于肺特异性白细胞介素-6(IL-6)敲除小鼠研究IL-6/糖蛋白130(gp130)/转录激活因子3(STAT3)通路在百草枯(PQ)诱导急性肺损伤(ALI)中的作用。方法野生型C57BL/6J小鼠分为IL-6野生型(IL-6 WT)组、IL-6 WT+PQ组,采用Sftpc(肺表面活性蛋白C基因)-Cre⁺小鼠与IL-6^FLOX/FLOX小鼠交配的方式得到肺特异性IL-6敲除小鼠并分为IL-6 KO组、IL-6 KO+PQ组,单次腹腔注射PQ诱导ALI,比较四组小鼠肺组织病理改变、肺泡动脉氧分压差(PA-aO₂)、肺组织湿/干质量比值(W/D)、IL-6/gp130/STAT3通路、核转录因子-κB(NF-κB) p65、肿瘤坏死因子-α(TNF-α)及白细胞介素-1β(IL-1β)的差异。结果与IL-6 WT组比较,IL-6 WT+PQ组小鼠肺组织出现了典型的ALI病理改变,肺组织胞浆蛋白中IL-6、gp130、p-STAT3、TNF-α、IL-1β表达水平及胞核蛋白中NF-κB p65的表达水平、PA-aO₂、W/D明显增加(P <0.05);与IL-6 WT+PQ组比较,IL-6 KO+PQ组小鼠肺组织病理改变明显改善,肺组织胞浆蛋白中IL-6、gp130、p-STAT3、TNF-α、IL-1β的表达水平及胞核蛋白中NF-κB p65的表达水平、PA-aO₂、W/D明显降低(P <0.05)。结论 IL-6/gp130/STAT3通路激活与PQ诱导ALI有关。     

Prevention, treatment and management of inflammation in atherosclerosis

Incidence rate of arteriosclerotic disease such as ischemic heart disease and stroke has been on the rise in Japan due to the westernized dietary habit, insufficient exercise brought about by persistent motorization and increase in mental stress caused by social downturn as well as rapid progression of aging society. In this paper, we'll outline prevention, treatment and control of arteriosclerosis from a perspective of antiinflammation.     

Vitamin D3 modulates the expression of bile acid regulatory genes and represses inflammation in bile duct-ligated mice

Vitamin D receptor (VDR), a nuclear receptor that regulates calcium homeostasis, has been found to function as a receptor for secondary bile acids. Because the in vivo role of VDR in bile acid metabolism remains unknown, we investigated the effect of VDR activation in a mouse model of cholestasis. We treated mice with 1alpha-hydroxyvitamin D(3) [1alpha(OH)D(3)] after bile duct ligation (BDL) and examined mRNA expression and cytokine levels. 1alpha(OH)D(3) treatment altered the expression of genes involved in bile acid synthesis and transport in the liver, kidney, and intestine but did not decrease bile acid levels in the plasma and liver of BDL mice. 1alpha(OH)D(3) treatment suppressed mRNA expression of proinflammatory cytokines in the liver and strongly decreased the plasma levels of proinflammatory cytokines in BDL mice. These findings indicate that 1alpha(OH)D(3) regulates a network of bile acid metabolic genes and represses proinflammatory cytokine expression in BDL mice. VDR ligands have the potential to prevent the cholestasis-induced inflammatory response.     

Cloning of novel soluble gp130 and detection of its neutralizing autoantibodies in rheumatoid arthritis

In an attempt to isolate disease-associated autoantigens in rheumatoid arthritis (RA), we cloned a new autoantigen named gp130-RAPS, which is a novel soluble form of the IL-6 signal-transducing molecule gp130. gp130-RAPS is a 50-kDa protein translated from alternatively spliced mRNA and has a truncated form of gp130 with a unique sequence, Asn-Ile-Ala-Ser-Phe (NIASF), in its COOH-terminus. We observed serum antibodies to this NIASF sequence frequently in patients with RA, but not in those with other systemic rheumatic diseases or in healthy subjects. In RA, detection of those antibodies was significantly associated with disease activity indices such as serum C-reactive protein (CRP) levels, erythrocyte sedimentation rate, blood platelet counts, and serum IL-6 concentration. In vitro experiments revealed that gp130-RAPS inhibited IL-6 activity, and this inhibition was neutralized by antibodies to the COOH-terminus of gp130-RAPS derived from patients with RA. Thus, autoantibody to gp130-RAPS may play an important role in the progression of RA by promoting IL-6 activity. Inspection of autoantibodies to gp130-RAPS may become a practical clinical test for RA. gp130-RAPS and its autoantibody provide a new clue to the complicated pathogenesis of RA.     

Increased atherosclerosis in myeloperoxidase-deficient mice

Myeloperoxidase (MPO), a heme enzyme secreted by activated phagocytes, generates an array of oxidants proposed to play critical roles in host defense and local tissue damage. Both MPO and its reaction products are present in human atherosclerotic plaque, and it has been proposed that MPO oxidatively modifies targets in the artery wall. We have now generated MPO-deficient mice, and show here that neutrophils from homozygous mutants lack peroxidase and chlorination activity in vitro and fail to generate chlorotyrosine or to kill Candida albicans in vivo. To examine the potential role of MPO in atherosclerosis, we subjected LDL receptor-deficient mice to lethal irradiation, repopulated their marrow with MPO-deficient or wild-type cells, and provided them a high-fat, high-cholesterol diet for 14 weeks. White cell counts and plasma lipoprotein profiles were similar between the two groups at sacrifice. Cross-sectional analysis of the aorta indicated that lesions in MPO-deficient mice were about 50% larger than controls. Similar results were obtained in a genetic cross with LDL receptor-deficient mice. In contrast to advanced human atherosclerotic lesions, the chlorotyrosine content of aortic lesions from wild-type as well as MPO-deficient mice was essentially undetectable. These data suggest an unexpected, protective role for MPO-generated reactive intermediates in murine atherosclerosis. They also identify an important distinction between murine and human atherosclerosis with regard to the potential involvement of MPO in protein oxidation.     

LIF受体α亚基和gp130细胞内区与U937细胞内信号分子Stat3 …

目的 探讨人白血病细胞系Ｕ９３７的白血病抑制因子（ＬＩＦ）受体α亚基和ｇｐ１３０亚基细胞内区与转录活性因子Ｓｔａｔ３的活性关系,旨在研究白血病细胞增殖和分化的机制。方法 用基因重组技术将２个基因在细胞内区截除（ｇｐ１９０ＥＸ、ｇｐ１３０ＥＸ）,并分别Ｕ９３７细胞中表达,因其可与野生型受体竞争性结合故可用免疫印迹法分析受体细胞内区截除后Ｓｔａｔ３的表达水平及该信号分子酷氨酸磷酸化。结果 转染ｇｐ１９     

Stat3-dependent acute Rantes production in vascular smooth muscle cells modulates inflammation following arterial injury in mice

Inflammation is a key component of arterial injury, with VSMC proliferation and neointimal formation serving as the final outcomes of this process. However, the acute events transpiring immediately after arterial injury that establish the blueprint for this inflammatory program are largely unknown. We therefore studied these events in mice and found that immediately following arterial injury, medial VSMCs upregulated Rantes in an acute manner dependent on Stat3 and NF-κB (p65 subunit). This led to early T cell and macrophage recruitment, processes also under the regulation of the cyclin-dependent kinase inhibitor p21^Cip1. Unique to VSMCs, Rantes production was initiated by Tnf-α, but not by Il-6/gp130. This Rantes production was dependent on the binding of a p65/Stat3 complex to NF-κB–binding sites within the Rantes promoter, with shRNA knockdown of either Stat3 or p65 markedly attenuating Rantes production. In vivo, acute NF-κB and Stat3 activation in medial VSMCs was identified, with acute Rantes production after injury substantially reduced in Tnfa^–/– mice compared with controls. Finally, we generated mice with SMC-specific conditional Stat3 deficiency and confirmed the Stat3 dependence of acute Rantes production by VSMCs. Together, these observations unify inflammatory events after vascular injury, demonstrating that VSMCs orchestrate the arterial inflammatory response program via acute Rantes production and subsequent inflammatory cell recruitment.