Methylglyoxal induces apoptosis mediated by reactive oxygen species in bovine retinal pericytes

One of the histopathologic hallmarks of early diabetic retinopathy is the loss of pericytes. Evidences suggest that the pericyte loss in vivo is mediated by apoptosis. However, the underlying cause of pericyte apoptosis is not fully understood. This study investigated the influence of methylglyoxal (MGO), a reactive alpha-dicarbonyl compound of glucose metabolism, on apoptotic cell death in bovine retinal pericytes. Analysis of internucleosomal DNA fragmentation by ELISA showed that MGO (200 to 800 microM) induced apoptosis in a concentration-dependent manner. Intracellular reactive oxygen species were generated earlier and the antioxidant, N-acetyl cysteine, inhibited the MGO-induced apoptosis. NF-kappaB activation and increased caspase-3 activity were detected. Apoptosis was also inhibited by the caspase-3 inhibitor, Z-DEVD-fmk, or the NF-kappaB inhibitor, pyrrolidine dithiocarbamate. These data suggest that elevated MGO levels observed in diabetes may cause apoptosis in bovine retinal pericytes through an oxidative stress mechanism and suggests that the nuclear activation of NF-kappaB are involved in the apoptotic process.     

肿瘤坏死因子-α对泡沫细胞胆固醇流出及ATP结合盒转运子A1表达的影响

目的探讨肿瘤坏死因子-α（TNF-α）对泡沫细胞胆固醇流出途径的影响及可能作用机制.方法采用人组织瘤细胞-1（THP-1）细胞诱导分化形成的泡沫细胞,测定TNF-α与细胞胆固醇流出的时间、浓度关系.然后给予饱和浓度的TNF-α刺激,随机将泡沫细胞分成对照组、TNF-α组、对甲苯磺酰L-苯丙氨酸甲基甲酮（N-α-tosyl-L-phenylalanine chloromethy ketone,TPCK）组及TPCK＋TNF-α组,以RT-PCR法、Western blot法测定细胞ATP结合盒转运子A1（ABCA1）的表达.结果TNF-α抑制细胞胆固醇流出呈时间、浓度效应,在10.0 ng/ml时,TNF-α抑制胆固醇流出达到饱和效应.10.0 ng/ml TNF-α刺激后以时间依赖方式下调ABCA1表达.TPCK预孵育后可部分逆转TNF-α对ABCA1表达的下调.结论炎症因子TNF-α可通过抑制ABCA1的表达而减少细胞胆固醇的流出,核因子κB（NF-κB）激活抑制剂TPCK可逆转TNF-α的上述影响,提示TNF-α抑制ABCA1表达与NF-κB激活有关.TNF α/NF-κB信号途径可抑制泡沫细胞的胆固醇流出,从而加重细胞内胆固醇的蓄积。     

NF-κB、Notch-1和Ki-67在结肠癌中的表达及其意义

目的 探索核因子κB(NF-κB)、Notch-1和Ki-67在结肠癌组织中的表达及其临床意义.方法 收集泸州医学院附属医院病理科2008年12月至2010年1月存档结肠蜡块120例,其中结肠腺瘤20例;结肠癌90例,包括高分化腺癌45例,中分化腺癌33例,低分化腺癌12例;结肠正常黏膜组织10例.采用免疫组织化学的方...     

IL-1β对ATDC5成软骨分化细胞miR-455-3p的影响

目的：检测IL-1β对ATDC5成软骨分化细胞miR-455-3p表达的影响,探索miR-455-3p在骨关节炎中的作用。方法诱导ATDC5细胞成软骨分化后,予10 ng/ml的IL-1β刺激,在刺激4、12、24、48 h时应用实时荧光定量PCR检测miR-455-3p、C/EBPβ和软骨特征性标记物的表达情况;并利用抑制剂IKK-NBD阻断NF-κB通路后,应用实时荧光定量PCR检测IL-1β作用下miR-455-3p的表达水平。结果在IL-1β作用下的ATDC5成软骨分化细胞中miR-455-3p、C/EBPβ和软骨退变标记物（ MMP13、ADAMTS5）均上调,而软骨基质合成标记物（ ACAN、COL2A1、SOX9）则下调,且后期更为明显;而IKK-NBD可抑制IL-1β诱导的miR-455-3p表达。结论 IL-1β可上调ATDC5成软骨分化细胞miR-455-3p的表达水平,且受NF-κB通路的调节。     

Inhibitory Effects of Parthenolide on the Angiogenesis Induced by Human Multiple Myeloma Cells and the Mechanism

The inhibitory effects of parthenolide （PTL） on angiogenesis induced by multiple myeloma （MM） cells in vitro and the mechanism were investigated. Human MM line RPMI8226 cells were cultured in vitro. The effects of MM culture supernatant on the migration and tubule formation ability of human umbilical vein endothelial cells （HUVECs） treated with PTL were observed. By using Western blot, the expression of p65 and IкB-α in MM cells was detected. RT-PCR was used to assay the expression of VEGF, IL-6, MMP2 and MMP9 mRNA in MM cells. ELISA was used to measure the levels of VEGF and IL-6 in MM cell culture supernatant. The expression of MMP2 and MMP9 in MM cells was examined by immunohistochemistry. （1） In 3.5, 5.0, 7.5 and 10 μmol/L PTL groups the number of migrated cells was 310±56, 207±28, 127±21 and 49±10 respectively, which was significantly different from that in positive control group （598±47） （P〈0.01）. In 3.5 and 5.0 μmol/L PTL groups the areas of capillary-like structures were 0.092±0.003 and 0.063±0.002 mm2, significantly less than in positive control group （0.262±0.012 mm2） （P〈0.01）, but in 7.5 and 10 μmol/L PTL groups no capillary-like structures were found; （2） After treatment with different concentrations of PTL for 48 h, the expression of p65 protein was gradually decreased, while that of IкB-α was gradually enhanced with the increased concentration of PTL; （3） After treatment with 3.5, 5.0, 7.5 and 10 μmol/L PTL for 48 h, the VEGF levels in the supernatant were 2373.4±392.2, 1982.3±293.3, 1247.0±338.4 and 936.5±168.5 pg/mL respectively, significantly different from those in positive control group （2729±440.0 pg/mL） （P〈0.05）. After treatment with 7.5 and 10 μmol/L PTL, the IL-6 levels in the culture supernatant were 59.6±2.8 and 41.4±9.8 pg/mL respectively, signifi- cantly lower than in positive control group （1287.3±43.5 pg/mL） （P〈0.05）; （4） RT-PCR revealed that PTL could significantly inhibit the expression of V     

Human Trim5α has additional activities that are uncoupled from retroviral capsid recognition

Trim5α is a host antiviral protein that recognizes incoming retroviral capsids in the cytoplasm and prevents productive infections. Although present in most mammals, the state of the Trim5 gene is dynamic in that primates have one copy with several splice variants, while rodents and cows have multiple copies. Mouse Trim30 (one of the mouse Trim5α homologs) has been shown to negatively regulate NF-kappaB activation by targeting upstream signaling intermediates TAB2 and TAB3 for degradation. We show that human Trim5α also affects levels of TAB2, resulting in abrogation of TAB2-dependent NF-kappaB activation. Surprisingly, unlike mouse Trim30, human and rhesus Trim5α are able to activate NF-kappaB-driven reporter gene expression in a dose-dependent manner. We show that Trim5α uses distinct domains for the distinct abilities of affecting TAB2 levels, regulating NF-kappaB, and recognizing retroviral capsids. Our results demonstrate functions of Trim5α that are not dependent on recognizing the retroviral capsid.     

NLRC5在弥漫性大B细胞淋巴瘤中的作用机制

弥漫性大B细胞淋巴瘤(DLBCL)是我国最常见的恶性淋巴瘤,大多首发自淋巴结.研究发现,核苷酸结合寡聚化结构域样受体(NLR)家族成员NLRC5在淋巴系细胞中表达明显,其可能是淋巴细胞肿瘤发生的重要基础.并且NLRC5能阻断信号传导途径中的核心组分核转录因子-κB(NF-κB),影响肿瘤发生发展.同时NF-κB的持续活化是DLBCL细胞生存的必要条件.因此,NLRC5很可能具有抑制过度炎症反应,进而抑制DLBCL的功能,其有望成为DLBCL免疫疗法的新靶点.