脂多糖增强小鼠腹腔巨噬细胞14.2 kD蛋白质磷酸化①

目的探索LPS对小鼠腹腔巨噬细胞小分子蛋白质磷酸化的影响。方法利用同位素掺入、SDS-PAGE、放射自显影和蛋白质印迹(Western blot)、结合蛋白激酶抑制剂与激活剂的使用,研究LPS对巨噬细胞处理后小分子蛋白质磷酸化及其相关蛋白激酶对此磷酸化的影响。结果14.2 kD蛋白质磷酸化被LPS强烈地促进;MAPK的表达量未见明显变化;TPK抑制剂三羟异黄酮(genistein)明显抑制上述磷酸化;PKA激活剂佛斯可林(forskolin)和Gi蛋白抑制剂百日咳毒素对上述磷酸化无明显影响。结论LPS能促进14.2 kD蛋白质的磷酸化,此磷酸化可能依赖酪氨酸蛋白激酶(TPK)。     

精—甘—天冬—丝氨酸肽抑制血小板活化的胞内信号转导机制

本工作在凝血酶活化的大鼠血小板上,观察ＲＧＤＳ肽对血小板聚集,蛋白磷酸化及丝裂素活化蛋白激酶（ＭＡＰＫ）活性的影响,结果发现,ＩＵ／ｍＬ凝血酶明显引起血小板聚集,９５和６６ｋＤ蛋白磷酸化及ＭＡＰＫ活性的增加,应用５０、１００、２００μｍｏｌ／ＬＲＧＤＳ肽共向孵育,呈浓度依赖地抑制凝血酶引起的血小板聚集和ＭＡＰＫ活性,且两者呈正相关（ｒ＝０．８１,Ｐ＜０．０１）。ＲＧＤＳ肽亦呈浓度依赖地抑制凝血酶诱导的９５和６６ＫＤ蛋白磷酸化,与其抑制ＭＡＰＫ活性呈明显正相关（ｒ＝０．４１,Ｐ＜０．０５和ｄ．５３,Ｐ＜０．０１）。提示,ＭＡＰＫ系统参与了凝血酶引起的Ｗ小板聚集,ＲＧＤＳ肽抑制血小板聚集机理之一可能是通过干预血小板内信号传导途径所致。     

失血性休克对内毒素血症小鼠CD14 mRNA表达的影响

观察家兔失血性休克合并门静脉源性轻度内毒素血症动物血压，血浆乳酸，β－Ｇ水平和死亡率的变化，结合小鼠腹腔巨噬细胞内ＣＤ１４ｍＲＮＡ的表达，并对休克增敏内毒素作用的机制进行初步分析。结果表明：输入ＬＰＳ后，失血休克＋ＬＰＳ组动物血压持续显著下降，血浆乳酸。β－Ｇ水平显著升高，且分别明显低于或高于单纯ＬＰＳ或ＨＳ组。     

七个成人型多囊肾病家系基因的诊断

应用ＰＫＤ１两侧四种探针（３’ＨＶＲ、ＰＧＧＧ１和另一侧的２４－１、２１８ＥＰ６），通过Ｓｏｕｔｈｅｒｎ印迹杂交、ＲＦＬＰ连锁分析，对成人型多囊肾病进行基因诊断的研究。在７个ＡＰＫＥ家系共４１个成员中，进行了基因单体型分析，１６个ＡＰＫＤ患者的ＲＦＬＰ单体型被证明与ＰＫＤ１基因相连锁，检测出６个症状前个体，发现２个重组体，结果表明用ＰＫＤ１两旁侧基因探针进行联合分析，可极有效地检出重组体，避免误诊，提高诊断的准确性。     

七个成人型多囊能病家系基因的诊断

应用ＰＫＤ１两侧四种探讨（３′ＨＶＲ，ＰＧＧＧ１和另一侧的２４－１，２１８ＥＰ６）通过Ｓｏｕｔｈｅｒｎ印迹杂交，ＲＦＬＰ连锁分析，对成人型多囊肾病进行基因诊断的研究，在７个ＡＰＫＥ家系共４１个成员中，进行了基因单体型分析，１６个ＡＰＫＤ的患者的ＲＦＬＰ单体型被证明与ＰＫＤ１基因相连锁，检测６个症状前个体，发现２个重组体，结果表明用ＰＫＤ两旁侧基因探针进行联合分析，可极有效地检出重组体，避免误诊，提     

ROS对小鼠腹腔巨噬细胞凋亡的影响

目的 探讨ＲＯＳ影响巨噬细胞凋亡的机制。方法 激光扫描共聚集显微术,流式细胞术和荧光标记技术等,结果（１）凋亡巨噬细胞内ＤＡＤＰＨ氧化酶活性急剧降低使得胞内ＲＯＳ水平快速上降;（２）ＲＯＳ清除剂促进地塞米松诱导的巨噬细胞凋亡;（３）ＰＫＣ促进巨细胞凋亡和ＲＯＳ急剧减少;ｃＡＭＰ抑制巨噬细胞凋亡和ＲＯＳ急剧减少。结论 （１）ＲＯＳ抑制地塞米松诱导的巨噬细胞凋亡;（２）ＰＫＣ,ｃＡＭＰ等因素通过影响地     

蛋白激酶C在调节血管内皮细胞通透性中的作用

蛋白激酶Ｃ(ｐｒｏｔｅｉｎｋｉｎａｓｅＣ ,ＰＫＣ)是一种钙或 /通过激活ＰＫＣ来增加内皮细胞的通透性 ,同时伴有细胞间连接缝隙增宽[2 ] 。而ＰＫＣ活性的抑制剂如隙形成 ,导致通透性的升高[9] 。2　参与调节内皮细胞通透功能的ＰＫＣ亚型和激活通路 ,引起蛋白质如细胞骨架蛋白的磷酸化 ,最终导ＤＡＧ再分别激活以Ｃａ2 +和ＰＫＣ为代表的两条信号ＰＫＣ活化和Ｃａ2 +升高 ;再由Ｃａ2 +与钙调蛋白结合形成Ｃａ2 +-ＣａＭ ,激活ＭＬＣＫ ;最后由ＭＬＣＫ介导ＭＬＣ蛋白激酶C在调节血管内皮细胞通透性中的作用@杨滔$第一军医大学病理生理…     

Src对细胞的肿瘤性转化和PDGF诱导的有丝分裂需要STAT3介导的Myc基因的表达

利用ＩκＢα磷酸化抑制剂Ｂａｙ11 70 85处理Ｕ937细胞 ,可诱导丝裂原激活的蛋白激酶 (ＭＡＰＫ)ｐ38(ｐ38ＭＡＰＫ)的磷酸化、明显的细胞凋亡、广泛的坏死和ＭＡＰＫＫ的弱磷酸化。Ｂａｙ11 70 85不影响磷酸化ＩκＢα的基础水平 ,但是能完全抑制由 12 肉豆蔻 13乙酸佛波脂 (ＰＭＡ)所诱导的ＩκＢα磷酸化。虽然Ｂａｙ11 70 85能阻断由ＰＭＡ诱导的ＮＦ κＢ的核移位 ,但一种能抑制ＮＦ κＢ核移位和功能的抑制剂ＳＮ5 0并不诱导细胞核和ＤＮＡ的碎裂、ｃａｓｐａｓｅ3的激活和细胞死亡。ｐ38ＭＡＰＫ特异性抑制剂ＳＢ2 0 35 80能完全…     

细菌毒素的受体和信号核转导

已知内毒素脂多糖（ＬＰＳ）与细胞膜相互作用的信号转导中有５个受体蛋白和３种可溶性蛋白起作用。哺乳动物细胞存在２种ＣＤ１４,即膜ＣＤ１４（ｍＣＤ１４）和可溶性ＣＤ１４（ｓＣＤ１４）。在单核巨噬细胞和中性粒细胞等髓样细胞表达的为ｍＣＤ１４,即ＧＰＩ－ＣＤ１４,连接于细胞外侧膜。血管内皮细胞和上皮细胞等非髓样细胞不表达ＣＤ１４。ＬＰＳ诱导的细胞活化需要血清中ｓＣＤ１４的参与,其Ｃ端缺乏ＧＰＩ尾。研究发现一种能与ＬＰＳ类脂体Ａ结合的６０ｋＤ糖蛋白ＬＢＰ,有结合区和调节区。ｍＣＤ１４作为ＬＰＳ的受体有３…     

PKA对跨膜型和分泌TNF—α胞毒效应的影响

目的：研究ＰＫＡ对跨膜型ＴＮＦα（ｍＴＮＦ－α）杀瘤效应的影响。方法：用ＴＮＦ生物活性检测方法在体外观察ＰＫＡ激活剂和抑制剂对一型ＴＮＦ－α杀伤不同肿瘤细胞的影响。结果：ＰＫＡ激活剂Ｆｏｒｓｋｏｌｉｎ（１０μｍｏｌ／Ｌ）和抑制剂Ｈ８（１５μｍｏｌ／Ｌ）可分别增强和抑制ｓＴＮＦ－α对其第三靶细胞的胞毒活性,对其余４株耐受细胞却无逆转使用,而且对ｍＴＮＦ－α的胞毒效应无任何影响。此外,ＰＫＡ活性增强,     

Tyrosine phosphorylation of a low molecular weight protein induced by RANTES in T-lymphocytes

The beta-chemokine RANTES, a T-lymphocyte activator, chemoattractant, and inducer of homotypic aggregation, is considered to exert extensive effects on T lymphocytes through either G protein-coupled or protein tyrosine kinase (PTK) signaling pathway. In the present study, we analyzed RANTES-induced signal transduction through PTK as an early event in T-lymphocyte activation. Tyrosine phosphorylation is detected by immunoblots in the human T-cell line H9 after incubation with human recombinant RANTES. The tyrosine phosphorylation of a protein with a molecular mass of about 25 kD is measurable as early as 30 s and maximal at 1-5 min; and is a dose-dependent effect. The phosphorylation response can be abrogated by the tyrosine-kinase inhibitor herbimycin A (HA) but is insensitive to heterotrimeric Galphai protein inhibitor pertussis toxin (Ptx). This phenomenon is also observed in a visible homotypic aggregation response after incubation serum-starved H9 cells with RANTES. The phosphorylation response can not be down-regulated by preincubation with either anti-CC chemokine receptor 5 (CCR5) antibody or HIV-1Bal supernatants. Our results suggest that tyrosine phosphorylation of a protein with molecular mass of about 25 kD via Src-family PTK(s) is an early event in T-lymphocyte activation associated with the homotypic aggregation in response to RANTES.     

Nuclear phosphotyrosyl-protein with DNA-binding ability in peripheral blood mononuclear cells from systemic lupus erythematosus patients.

This study examined the phosphorylation of cytoplasmic and nuclear proteins in peripheral blood mononuclear cells (PBMC) of systemic lupus erythematosus (SLE) patients. The cytoplasmic and nuclear protein kinase activity in PBMC from SLE patients was at least five-fold higher than that of normal healthy subjects. PBMC of SLE patients produced different nuclear endogenous substrates on phosphorylation and also displayed distinct protein kinase activity. Nuclear phosphoproteins, with human PBMC DNA-binding ability, of 38 kD and 70 kD were detected from both SLE patients and normal healthy subjects, while the 40 kD phosphoprotein, with tyrosine as the main phosphorylation residue, was found only in SLE patients. Other nuclear phosphoproteins, and most of the detected cytoplasmic phosphoproteins, were present in higher levels in both normal PBMC with mitogen stimulation, such as PHA, and SLE PBMC. The expression level of the 40 kD nuclear phosphotyrosyl-protein showed a positive correlation with the clinical disease activity of SLE. These results suggest that PBMC from SLE patients had distinct tyrosine protein kinase (TPK) activity and/or a different endogenous substrate of nuclear DNA-binding proteins in tyrosine phosphorylation. The possible significance of tyrosine phosphorylation in PBMC of SLE patients in the pathogenesis, and its clinical meaning, are discussed.     

微囊介导VE-Cad胞吞参与了LPS作用后血管通透性增高的形成

目的:观察脂多糖(lipopolysaccharide,LPS)作用后微囊介导的血管内皮钙黏蛋白(vascular endothelial cadherin,VE-Cad)胞吞,及其在血管通透性增高中的作用。方法:采用人血管内皮细胞株CRL-2922,以及免疫组化、免疫印迹、免疫共沉淀等技术方法,观察LPS处理后不同时点细胞质膜微囊重要结构蛋白小窝蛋白1(caveolin-1,Cav1)的蛋白表达和磷酸化,Cav1与VE-Cad的共沉淀和共定位,以及微囊抑制剂对LPS处理后Cav1与VE-Cad的共沉淀、VE-Cad质膜表达和单层细胞通透性的影响。结果:(1)LPS处理后Cav1蛋白表达无显著变化,但其Tyr14位点的磷酸化水平逐渐增高(P0.05),Cav1与VE-Cad的免疫共沉淀逐渐增多(P0.05),免疫组化激光共聚焦显微镜观察在4 h时可见明显的共定位;(2)细胞质膜微囊抑制剂非律平(5 mg/L)可以显著减少LPS处理4 h Cav1与VE-Cad的免疫共沉淀(P0.05),增强VE-Cad的质膜表达(P0.05),改善单层细胞通透性(P0.05)。结论:细胞质膜微囊介导VE-Cad胞吞参与了LPS作用后血管通透性增高的形成。     

Porins from Salmonella enterica serovar Typhimurium activate the transcription factors activating protein 1 and NF-kappaB through the Raf-1-mitogen-activated protein kinase cascade.

In this study we examined the ability of Salmonella enterica serovar Typhimurium porins to activate activating protein 1 (AP-1) and nuclear factor kappaB (NF-kappaB) through the mitogen-activated protein kinase (MAPK) cascade, and we identified the AP-1-induced protein subunits. Our results demonstrate that these enzymes may participate in cell signaling pathways leading to AP-1 and NF-kappaB activation following porin stimulation of cells. Raf-1 was phosphorylated in response to the treatment of U937 cells with porins; moreover, the porin-mediated increase in Raf-1 phosphorylation is accompanied by the phosphorylation of MAPK kinase 1/2 (MEK1/2), p38, extracellular-signal-regulated kinase 1/2, and c-Jun N-terminal kinase. We used three different inhibitors of phosphorylation pathways: 2'-amino-3'-methoxyflavone (PD-098059), a selective inhibitor of MEK1 activator and the MAPK cascade; 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580), a specific inhibitor of the p38 pathway; and 7beta-acetoxy-1alpha,6beta,9alpha-trihydroxy-8,13-epoxy-labd-14-en-11-one (forskolin), an inhibitor at the level of Raf-1 kinase. PD-098059 pretreatment of cells decreases AP-1 and NF-kappaB activation by lipopolysaccharide (LPS) but not by porins, and SB203580 pretreatment of cells decreases mainly AP-1 and NF-kappaB activation by porins; in contrast, forskolin pretreatment of cells does not affect AP-1 and NF-kappaB activation following either porin or LPS stimulation. Our data suggest that the p38 signaling pathway mainly regulates AP-1 and NF-kappaB activation in cells treated with S. enterica serovar Typhimurium porins. Antibody electrophoretic mobility shift assays showed that JunD and c-Fos binding is found in cells treated with porins, in cells treated with LPS, and in unstimulated cells. However, by 30 to 60 min of stimulation, a different complex including c-Jun appears in cells treated with porins or LPS, while the Fra-2 subunit is present only after porin stimulation. These data suggest different molecular mechanisms of activation induced by porins or by LPS.     

Inhibiting Mer receptor tyrosine kinase suppresses STAT1, SOCS1/3, and NF-κB activation and enhances inflammatory responses in lipopolysaccharide-induced acute lung injury

Mer signaling participates in a novel inhibitory pathway in TLR activation. The purpose of the present study was to examine the role of Mer signaling in the down-regulation of TLR4 activation-driven immune responses in mice, i.t.-treated with LPS, using the specific Mer-blocking antibody. At 4 h and 24 h after LPS treatment, expression of Mer protein in alveolar macrophages and lung tissue decreased, sMer in BALF increased significantly, and Mer activation increased. Pretreatment with anti-Mer antibody did not influence the protein levels of Mer and sMer levels. Anti-Mer antibody significantly reduced LPS-induced Mer activation, phosphorylation of Akt and FAK, STAT1 activation, and expression of SOCS1 and -3. Anti-Mer antibody enhanced LPS-induced inflammatory responses, including activation of the NF-κB pathway; the production of TNF-α, IL-1β, and MIP-2 and MMP-9 activity; and accumulation of inflammatory cells and the total protein levels in BALF. These results indicate that Mer plays as an intrinsic feedback inhibitor of the TLR4- and inflammatory mediator-driven immune responses during acute lung injury.     

Activation of natural killer cells via the Fc gamma RIII (CD16) requires initial tyrosine phosphorylation.

Triggering of the Fc gamma RIII (CD16) on natural killer (NK) cells by monoclonal antibodies or antibody-coated target cells stimulates a rapid phospholipase C (PLC)-mediated hydrolysis of inositol phospholipids and results in subsequent delivery of the lytic hit. The role of initial tyrosine phosphorylation in these events was investigated with a tyrosine protein kinase (TPK) inhibitor, genistein. At doses that inhibited CD16-triggered tyrosine phosphorylation of substrates in intact cells, genistein did not influence serine/threonine phosphorylation or target cell binding but prevented PLC activation, cell-mediated cytotoxicity and antibody-dependent cellular cytotoxicity. These findings indicate that tyrosine phosphorylation is an early and critical event during receptor-mediated activation of the lytic machinery.     

Lipopolysaccharide (LPS) Induces the Apoptosis and Inhibits Osteoblast Differentiation Through JNK Pathway in MC3T3-E1 Cells

Bone degradation is a serious complication of chronic inflammatory diseases such as septic arthritis, osteomyelitis, and infected orthopedic implant failure. Up to date, effective therapeutic treatments for bacteria-caused bone destruction are limited. In our previous study, we found that LPS promoted osteoclast differentiation and activity through activation of mitogen-activated protein kinases (MAPKs) pathway such as c-Jun N-terminal kinases (JNK) and extracellular signal regulated kinase (ERK1/2). The current study was to evaluate the mechanism of LPS on the apoptosis and osteoblast differentiation in MC3T3-E1 cells. MC3T3-E1 osteoblasts were non-treated, treated with LPS. After treatment, the cell viability, the activity of alkaline phosphatase (ALP) and caspase-3 were measured. The expressions of osteoblast-specific genes and Bax, Bcl-2, and caspase-3 were determined by real-time quantitative polymerase chain reaction (qPCR). Protein levels of Bax, Bcl-2, caspase-3, and phosphorylation of MAPKs were measured using Western blotting assays. The MAPK signaling pathway was blocked by pretreatment with JNK inhibitor SP600125. LPS treatment induced a significant decrease in cell metabolism, viability, and ALP activity in MC3T3-E1 cells. LPS also significantly decreased mRNA expressions of osteoblast-related genes in MC3T3-E1 cells. On the other hand, LPS significantly upregulated mRNA expressions and protein levels of Bax and caspase-3 as well as activation of caspase-3, whereas decreased Bcl-2 expression in MC3T3-E1 cells. Furthermore, LPS significantly promoted MAPK pathway including the phosphorylation of JNK and the phosphorylation of ERK1/2; moreover, pretreatment with JNK inhibitor not only attenuated both of phosphorylation-JNK and ERK1/2 enhanced by LPS in MC3T3-E1 cells, but also reversed the downregulated expressions of osteoblast-specific genes including ALP and BSP induced by LPS. In conclusion, LPS could induce osteoblast apoptosis and inhibit osteoblast differentiation via activation of JNK pathway.     

Lipopolysaccharide-induced cytokine production in human monocytes: Role of tyrosine phosphorylation in transmembrane signal transduction

The signal transduction events that follow the binding of lipopolysaccharide (LPS) to the macrophage cell surface are not well defined. In the current studies LPS was found to induce alterations in phosphorylation of monocyte proteins on tyrosine. Herbimycin A and genistein, inhibitors of tyrosine kinases, markedly attenuated LPS-induced tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) protein and mRNA production. Reciprocally, the tyrosine phosphatase inhibitor sodium orthovanadate enhanced LPS-induced production of TNF-α. LPS induced a concentration-dependent increase in tyrosine phosphorylation of several proteins, which paralleled and preceded the onset of LPS-induced TNF-α production. LPS stimulation had different but reproducible effects on three members of the src family of tyrosine kinases. Both Hck and Lyn kinase activity increased before the onset of TNF-α production, consistent with their participation in the observed LPS-induced tyrosine phosphoprotein accumulation. In contrast, Yes kinase activity was not affected. These observations were made at concentrations of LPS that required serum rich in LPS-binding protein and the monocyte surface antigen CD14 for TNF-α production. These data indicate that tyrosine kinases and phosphatases are involved in the signal transduction cascade by which LPS induces production of TNF-α and IL-6 by human monocytes, and suggest that Lyn and Hck are candidate participants in this process.     

Cisplatin-induced activation of murine bone marrow-derived macrophages require protein tyrosine phosphorylation

The aim of the present study is to evaluate the involvement of tyrosine phosphorylation in the signal transduction mechanism of cisplatin-induced macrophage activation in vitro. Stimulation of bone marrow-derived macrophages (BMDM) with cisplatin (CP) resulted in a time- and dose-dependent phosphorylation of several proteins having estimated molecular weights of approximately 18, 20, 21, 30, 33, 35, 39, 41, 44, 58 and 123 kD, detected by immunoblot using anti-phosphotyrosine antibody. CP-induced tyrosine phosphorylation was inhibited by the tyrosine kinase inhibitor genistein. Using this inhibitor, we were able to correlate tyrosine phosphorylation with several functional effects of CP on murine bone marrow-derived macrophages (BMDM) . Treatment of macrophages with genistein before incubation with CP completely inhibited the CP-induced tumoricidal activation of macrophages as well as production of TNF and NO, whereas pre-treatment of macrophages with phosphatase inhibitor sodium vanadate upregulated macrophage activation in addition to enhanced protein tyrosine phosphorylation. Taken together, these data suggest that tyrosine phosphorylation play a critical regulatory role in the activation of macrophages with CP.     

表皮生长因子对卵巢激活素基因表达的调节及其信号通路

背景：激活素作为卵巢内调控分子,对卵巢卵泡发育起着重要作用。 目的：探索表皮生长因子在激活素基因表达过程中所起的重要作用以及可能参与调节的信号通路。 方法：分离斑马鱼卵巢卵泡,体外培养6 d,消化后传代培养24 h。表皮生长因子单独或与其他分子抑制剂(AG1478、H89、GF109203X)或激动剂(FK、PMA)联合处理细胞,提取细胞RNA,反转录PCR检测细胞激活素表达量。 结果与结论：表皮生长因子可快速提高激活素表达量,其作用可能是通过磷酸化信号分子丝裂原活化蛋白激酶实现,而蛋白激酶C特异性抑制剂或激动剂可减弱或加强表皮生长因子对丝裂原活化蛋白激酶信号分子的激活,显示卵巢内激活素表达受表皮生长因子调节,蛋白激酶C/丝裂原活化蛋白激酶信号通路参与了这种调节作用。蛋白激酶A抑制剂也能抑制表皮生长因子对激活素表达的促进作用。