Antioxidant Activity of Plicatin B on Cultured Human Microvascular Endothelial Cells Exposed to H2O2

Oxidative stress plays a crucial role in the pathogenesis of atherosclerosis by promoting endothelial dysfunction and impairing vascular relaxation. Flavonoids are largely investigated for their biological properties and particularly for their scavenging and antioxidant properties. In the current study, we evaluated the clastogenicity of the chalcone plicatin B in peripheral human lymphocytes (whole blood and pure lymphocytes) as well as its antioxidant activity and its ability to contrast dysfunction on human microvascular endothelial cells (HMEC-1) exposed to hydrogen peroxide. We measured in the cell culture medium the levels of 8-isoprostane, NO_x, ET-1, and ICAM-1, as well as the expression of e-NOS, prepro-ET-1, and ICAM-1. In conclusion, our results demonstrate that the chalcone plicatin B (1–10 μM) may represent a good candidate for the prevention of atherosclerosis, as it consistently reduces the oxidative/inflammatory process and is not genotoxic to human lymphocytes.     

Análisis comparativo de la expresión de metaloproteasas (MMP-2, MMP-9, MMP-11 y MMP-13) y del inhibidor tisular de la metaloproteasa 3 (TIMP-3) entre las biopsias previas negativas y las prostatectomías radicales

Metalloproteases (MMPs) and tissue inhibitor of metalloprotease-3 (TIMP-3) have been associated to the risk of having cancer and tumor aggressiveness. When facing the difficulties of prostate cancer diagnosis, the expression of MMPs and TIMP-3 in negative biopsies could be helpful to evaluate a diagnostic suspicion. Our objective is to carry out a comparative study of the expression of MMPs and TIMP-3 in previous negative biopsies and radical prostatectomies (RP).Material and methodsRetrospective analysis of a hospital-based cohort including 21 patients with suspicion of prostate carcinoma, whose expressions of MMP-2, 9, 11 and 13 and TIMP-3 were evaluated by immunohistochemistry in the tumor area from previous negative biopsies and RP.ResultsImmunohistochemical staining values (Score) for MMPs (-11 and -13) and TIMP-3 showed no significant differences when comparing the areas of negative biopsies where tumors subsequently developed with those of the RP. However, we did observe a significant difference in the increased expression of MMP-2 (P = .002) and MMP-9 (P = .001) in the tumor area of the RP with respect to the corresponding area of the previous negative biopsy.ConclusionsOur data indicate a higher overall expression of MMP-2 and MMP-9 in the tumor area of the RP compared to the corresponding areas of the negative previous biopsy, which seems to be associated to the process of malignant transformation.     

The Effect of Ras Inhibition on the Proliferation, Apoptosis and Matrix Metalloproteases Activity in Rat Hepatic Stellate Cells

In vivo inhibition of Ras by its antagonist farnesylthiosalicylic acid (FTS) prevents and reverses liver fibrosis in a rat model. In this study we showed the in vitro effects of Ras inhibition in a rat hepatic stellate cell line, HSC-T6. The IC₅₀ of FTS that inhibited PDGF-induced proliferation was 15 μM. FTS, by itself or in combination with PDGF, induced a three- to fivefold increase in the number of apoptotic stellate cells but did not induce apoptosis in cells cultured with TGFβ1. We observed increased activity of MMP-9 and MMP-2 induced by FTS in combination with PDGF or TGFβ. FTS, alone or in the presence of PDGF and TGFβ, reduced collagen I mRNA expression. In conclusion, the in vivo amelioration of liver fibrosis by FTS may be explained by its ability to inhibit hepatic stellate cell proliferation, induce apoptosis and MMP-2 and MMP-9 activity, and decrease collagen I expression.     

Cellular localization and expression of gp63 homologous metalloproteases in Leishmania (Viannia) braziliensis strains

Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that encompasses a broad spectrum of clinical manifestations. In a previous study, we showed that Brazilian and Colombian L. braziliensis strains, isolated from patients with distinct clinical manifestations, display different pattern of metalloprotease activities. Following these results, we investigated the cellular localization of these molecules and their relation to the major surface protease (gp63) of Leishmania. Comparative analyses of metalloprotease expression among different clinical isolates as well as an evaluation of the effect of long-term in vitro passage on the expression pattern of these metalloproteases were also performed. Western blot analysis, using an anti-gp63 antibody, revealed polypeptide patterns with a similar profile to that observed in zymographic analysis. Flow cytometry and fluorescence microscopy analyses corroborated the presence of metalloproteases with homologous domains to gp63 in the parasites and revealed differences in the expression level of such molecules among the isolates. The cellular distribution of metalloproteases, assessed by confocal analysis, showed the existence of intracellular metalloproteases with homologous domains to gp63, predominantly located near the flagellar pocket. Finally, it was observed that differential zymographic profiles of metalloproteases exhibited by L. (V.) braziliensis isolates remain unaltered during prolonged in vitro culture, suggesting that the proteolytic activity pattern is a stable phenotypic characteristic of these parasites.     

低氧通过HIF-1α调控髓核细胞中ADAMTS-4和ADAMTS-5的表达

目的观察低氧环境及低氧诱导因子1α(HIF-1α)对髓核细胞中解聚蛋白样金属蛋白酶(ADAMTS)-4和ADAMTS-5启动子活性的影响,探讨可能影响椎间盘退变的分子机制。方法将体外培养的大鼠髓核细胞分别置于常氧和低氧(1%O2)培养箱培养,采用蛋白质印迹分析及PCR方法检测细胞中ADAMTS-4和ADAMTS-5的表达。对获取的ADAMTS-4和ADAMTS-5启动子片段测序,并使用JASPAR数据库分析其中是否存在HIF-1α的结合位点。将HIF-1α过表达质粒、PGL3-ADAMTS-4质粒和PGL3-ADAMTS-5质粒转染至大鼠髓核细胞中,用双荧光素酶报告基因检测系统检测髓核细胞中HIF-1α对ADAMTS-4和ADAMTS-5基因启动子的调控作用。结果蛋白质印迹分析和PCR结果显示,低氧分别在蛋白质水平和m RNA水平抑制髓核细胞中ADAMTS-4、ADAMTS-5的表达。使用JASPAR软件分析后,发现ADAMTS-4启动子中可能包含1个HIF-1α的结合位点,而ADAMTS-5启动子中可能包含2个HIF-1α的结合位点。双荧光素酶报告基因检测结果显示,HIF-1α的过表达能够显著抑制ADAMTS-4和ADAMTS-5启动子活性。结论低氧可能通过HIF-1α抑制ADAMTS-4和ADAMTS-5的表达,保持椎间盘内环境的稳态,延缓椎间盘退变的发生。     

Glomerulopathic Light Chain-Mesangial Cell Interactions Modulate in Vitro Extracellular Matrix Remodeling and Reproduce Mesangiopathic Findings Documented in Vivo

Glomerulopathic light chains (LCs) are associated with two distinct mesangiopathies: AL (light-chain-related) amyloidosis and light-chain deposition disease (LCDD) with immunomorphologic features that are well documented in the literature. Even though both conditions are caused by monoclonal LCs, these entities differ dramatically in their morphologic expressions. In AL amyloidosis the mesangial matrix is replaced by amyloid fibrils, while in LCDD the matrix increases as a consequence of deposition of excess extracellular matrix (ECM). The immunomorphologic mesangial alterations observed in biopsy material are closely reproduced in vitro when mesangial cells grown on an artificial matrix are incubated with monoclonal light chains obtained from the urine of patients with either condition. This article summarizes previously reported data, reports new findings, and focuses on integrating all the available information on the subject. When mesangial cells are incubated with LCDD-LCs, production of ECM proteins (collagen IV, laminin, fibronectin, and tenascin) is increased, with maximum effect at 72 hours post LC treatment. A concomitant decrease in collagenase IV activity further accentuates the accumulation of mesangial matrix. These effects are mediated through transforming growth factor-beta (TGF-beta) activation. In contrast, when mesangial cells are incubated with Am-LCs, a decrease in ECM protein production and a stimulatory effect on collagenase IV is observed, which results in matrix degradation and facilitates amyloid deposition. The decreased TGF-beta documented in the literature in this setting precludes adequate matrix repair. These findings substantiate the morphologic alterations observed in renal biopsy specimens and in the in vitro model. Using this in vitro model, it is then possible to delineate the LC interactions with putative receptors at the mesangial cell surface that regulate mesangial cell pathobiologic responses and mesangial matrix homeostasis.     

解整合素-金属蛋白酶33基因多态性与慢性阻塞性肺疾病易感性的荟萃分析

目的 运用荟萃分析的方法探讨解整合素-金属蛋白酶33 (ADAM33)基因多态性与COPD易感性的关系.方法 全面检索PubMed、中国知网、重庆维普中文科技期刊全文数据库、万方科技期刊全文数据库获取ADAM33基因多态性与COPD易感性的病例对照研究,根据纳入及排除标准筛选文献并提取数据.采用等位基因遗传模型、显性遗传模型、隐性遗传模型、共显性遗传模型分别评价COPD发病的相对危险度,合并效应采用比值比(OR)和95％可信区间(95％CI).并通过人种分组,对各基因多态性进行亚组分析.发表偏倚通过漏斗图直观判断和Egger回归法、Begg秩相关法检验.结果 共6篇文献(6个病例-对照研究)被纳入,共有2 371例研究对象(其中1 174例为COPD患者,1 197例为正常对照者)被纳入荟萃分析.Meta分析结果表明,无论在亚洲人还是高加索人中,ADAM33 F+1基因多态性与COPD易感性无关联.而Q-1 G/A与亚洲人种COPD患者易感性无关(OR=1.289,95％CI=0.759～2.190,P=0.347),与高加索人种COPD易感性有关(OR =1.651,95％ CI=1.178～2.314,P=0.004).ADAM33 Q-1 G/A与COPD有关联(OR=1.421,95％ CI =1.014～1.991,P=0.042).亚组分析显示,Q-1 G/A基因多态性与亚洲人COPD易感性无关(OR=1.289,95％CI =0.759～2.190,P=0.347);与高加索人COPD易感性有关(OR =1.651,95％ CI =1.178～2.314,P=0.004).结论 ADAM33 F+ 1T/C基因多态性可能与COPD易感性没有相关性,ADAM33 Q-1 G/A等位基因G可能是COPD的易感因素.     

脂氧素A4对脂多糖活化小鼠巨噬细胞NF-κB和TNF-α转化酶的影响

目的 研究脂氧素A4（LXA4）对脂多糖（LPS）活化的小鼠巨噬细胞NF-κB及TNF-α转化酶的影响。方法 小鼠RAW 264．7巨噬细胞株培养于细胞培养板,随机分为空白对照组、LPS处理组（LPS 1μg/ml）和LPS＋LXA4组（LPS 1μg/ml＋LXA4 10^-7mol/L）。酶联免疫吸附法测定上清液TNF-α水平,提取细胞总蛋白,Western blot法测定NF-κB p65、IκB-α及TNF-α转化酶含量,荧光素酶报告质粒测定NF-κB活性。结果 LXA4抑制LPS活化的RAW 264．7巨噬细胞IκB-α降解、NF-κB p65核转位及NF-κB活性,同时抑制TNF-α蛋白表达和上调TNF-α转化酶蛋白表达。结论 LXA4通过抑制NF-κB活性和下调TNF-α转化酶表达而减少LPS活化的RAW264．7巨噬细胞分泌TNF-α。     

Regulation of cell surface APO-1/Fas (CD95) ligand expression by metalloproteases

APO-1/Fas (CD95) ligand (APO-1L) induces apoptosis in sensitive target cells. Activation-induced T cell death and Ca²⁺-independent cytotoxicity in perforin knockout mice are mediated by APO-1L. To define whether APO-1L is expressed on the surface of activated T cells and to investigate the mechanisms leading to the release of a soluble form, we developed rabbit anti-APO-1L antibodies (Ab). The purified rabbit Ab detected the mature forms of the human and mouse APO-1L of approximately 42 and 40kDa. In addition, the Ab recognized the non-glycosylated form of APO-1L of approximately 32-33 kDa. In activated human T cells, the soluble form of APO-1L was detectable with a moleculas mass of 26 kDa. Immunofluorescence of three human T lymphoblastoid cell lines showed that activation of these cells by phorbol 12-myristate 13-acetate/ionomycin induced a significant increase in cell surface APO-1L only in the presence of metalloprotease inhibitors. Zn²⁺, but not Ca²⁺, prevented the increase in surface APO-1L observed in the presence of 1,10-phenanthroline. Blocking of other classes of proteases (serine- and acid-proteases, chymotrypsin) had no effect. Increased expression of surface APO-1L by metalloprotease inhibitors was not dependent on T cell activation, as the metalloprotease inhibitors also modulated the low level of constitutive APO-1L expression. These results suggest that cell surface expression of human APO-1L is regulated by Zn²⁺-dependent metalloproteases. Cleavage of surface APO-1L may act as a regulatory mechanism to prevent accumulation of the membrane-bound form and may cause systemic effects of the APO-1L.