重组人表皮生长因子对中毒性急性肾小管坏死恢复的促进作用

目的：探讨国产重组人表皮生长因子(recombinant human epidermal growth factor, rhEGF)对庆大霉素（gentamicin, GM）中毒性急性肾小管坏死的恢复是否具有促进作用并探讨其机制。方法：将成年Wistar大鼠随机分成3组。GM组,GM皮下注射2 d,400 mg/（kg·d）;EGF组,按上法注射GM,于最后1次注射GM后2 h开始rhEGF皮下注射3 d,90 μg/d;对照组,注射等量生理盐水代替GM。分别于首次注射GM后第2,5,8,11,15,22和29天处死各组大鼠并观察肾功能指标及肾脏组织形态学的改变,包括HE,PAS染色分级,并用免疫组织化学的方法检测肾脏组织中热休克蛋白27（heat shock protein 27,HSP27）的表达。结果：GM注射大鼠肾功能明显受损,但EGF组肾功能损伤程度较GM组轻,并提前恢复正常。组织学分级比较显示,第11和15天EGF组明显好于GM组。免疫组织化学结果显示,EGF组HSP27的表达强于GM组。结论：国产rhEGF具有促进GM中毒性急性肾小管坏死形态和功能恢复的作用,这可能与其促进小分子量热休克蛋白的表达有关。     

Proteomic analysis of zebrafish (Danio rerio) infected with infectious spleen and kidney necrosis virus

Iridovirus infections remain a severe problem in aquaculture industries worldwide. Infectious spleen and kidney necrosis virus (ISKNV), the type species of the genus Megalocytivirus in the family Iridoviridae, has caused significant economic losses among freshwater fish in different Asian countries. To investigate the molecular mechanism of iridoviral pathogenesis, we analyzed the differential proteome from the spleen of ISKNV-infected zebrafish through two-dimensional gel electrophoresis (2-DE). Mass spectrometry revealed 35 altered cellular protein spots, including 15 upregulated proteins and 20 downregulated proteins at five days post-infection. The altered host proteins were classified into 13 categories based on their biological processes: cytoskeletal protein, stress response, lipoprotein metabolism, ubiquitin-proteasome pathway, carbohydrate metabolism, signal transduction, proteolysis, ion binding, transport, metabolic process, catabolic process, biosynthesis, and oxidation reduction. Moreover, 14 corresponding genes of the differentially expressed proteins were validated by RT-PCR. Western blot analysis further demonstrated the changes in α-tubulin, β-actin, HSC70, and major capsid protein (MCP) during infection. β-Actin was selected for further study via co-immunoprecipitation analyses, which confirmed that the cellular β-actin interacts with the MCP protein of ISKNV in the infected zebrafish. These findings provide insight into the interactions between iridoviruses (especially ISKNV) and host, as well as the mechanism and pathogenesis of ISKNV infections.     

一种通过表皮生长因子受体介导的基因转移系统

目的发展一种针对表皮生长因子过量表达的肿瘤细胞的基因转移系统。方法人工合成了一种Ｎ端含多个赖氨酸残基，Ｃ端为人表皮生长因子（ＥＧＦ）的受体结合域的３３肽，此合成肽（Ｋ９Ｅ肽）既具有ＤＮＡ结合活性，又能为细胞表面ＥＧＦ受体所识别并内在化。Ｋ９Ｅ肽与萤火虫荧光素酶表达质粒ｐＥＢｌｕｃ按一定比例结合形成核酸复合物，以此为基础，利用受体介导的基因转移技术，组建了外源基因转移系统。结果核酸复合物直接加入于类上皮癌细胞Ａ４３１的培养液中，４８小时后可从细胞裂解液中测出荧光素酶的显著表达。结论该系统可特异性地将外源基因导入ＥＧＦ受体过量表达的肿瘤细胞。     

Targeting human epidermal growth factor receptor 2 by a cell-penetrating peptide-affibody bioconjugate

Cell-penetrating peptide (CPP)-based delivery systems represent a strategy that facilitates DNA import efficiently and non-specifically into cells. To introduce specificity, we devised an approach that combines a cell-penetrating peptide, TAT-Mu (TM) and a targeting ligand, an HER2 antibody mimetic-affibody (AF), designated as TMAF to deliver nucleic acids into the cells. In this study, we synthesized TMAF protein and its truncated versions, i.e. MAF and AF, by expressing the corresponding plasmids in Escherichia coli BL21(DE3)pLysS cells. Purified TMAF binds DNA efficiently and protects plasmid DNA from DNaseI action. Transfection of HER2+ breast cancer cell lines MDA-MB-453, SK-OV-3, SK-BR-3 and an ovarian cancer cell line with plasmid DNA pCMVβ-gal, resulted in enhanced β-galactosidase activity when compared to control MDA-MB-231 cells. Maximal activity observed in MDA-MB-453 cells at DNA:TMAF:Protamine sulphate (PS) corresponding to 1:8:2 charge ratios. Further the observed gene transfection was resistant to serum, sensitive to the presence of free AF and non-toxic. Variants of TMAF although non-toxic, were far less efficient indicating the effective role of the TAT and Mu domains. The observed DNA uptake and reporter gene activity mediated by TMAFin vitro could be linked with the cell-surface density of tyrosine kinase receptor HER2 (ErbB2) levels estimated by Western blot. Further, we confirmed the efficacy of DNA transfer by TMAF protein in xenograft mouse models using MDA-MB-453 cells. Expression of β-galactosidase as the reporter gene, upon intratumoral injection of DNA, in complex with TMAF, lends credence to specific DNA import and distribution within the tumor tissue that was attributed to high HER2 receptor overexpression in MDA-MB-453 cells. Through delivery of anti-TF hshRNA: TMAF: PS complex, we demonstrate specific knockdown of tissue factor (TF) in MDA-MB-453 cells in vitro. Most importantly, in a xenograft mouse model, we observe significant (P < 0.05) and specific reduction of tumor volume when anti-TF hshRNA: TMAF: PS complex was injected intratumorally. Collectively our data indicate that AF-based chimeric peptides with nucleic acid binding properties may provide an effective tumor specific strategy to deliver therapeutic nucleic acids.     

Enhancement of fibroblastic proliferation on chitosan surfaces by immobilized epidermal growth factor

Chitosan membranes were modified with mouse epidermal growth factor (EGF) by a photochemical technique. Photochemical immobilization was performed via a two-step process, in which EGF was first reacted with a heterobifunctional cross-linker sulfo-SANPAH (sulfosuccinimidyl 6(4'-azido-2'-nitrophenyl-amino)hexanoate) and then immobilized on the chitosan membrane by UV irradiation. The success of immobilization process was checked by Fourier transform infrared attenuated total reflection spectroscopy and X-ray photoelectron spectroscopy. Atomic force microscopy was used to evaluate the surface topography. The mitogenic effect of the EGF-modified chitosan membrane was investigated using mouse fibroblasts (L929 cell line), and cell proliferation was investigated by MTT and crystal violet assays. The results obtained from cell culture experiments showed that immobilized EGF stimulated fibroblast growth on chitosan membranes, and a considerable difference in cell proliferation was detected on EGF-modified chitosan membranes.     

不同血清浓度对bFGF联合EGF诱导BMSCs向神经细胞分化的影响

目的:探讨不同血清浓度条件下碱性成纤维生长因子(basic fibroblast growth factor,bFGF)联合表皮生长因子(epidermal growth factor,EGF)诱导骨髓间充质干细胞(bone mesenchymal stem cells,BMSCs)向神经细胞分化方向的影响。方法:全骨髓贴壁法体外分离培养BMSCs,流式细胞法检测BMSCs表面骨髓基质标志CD90和造血细胞标志CD45,MTT法绘制第3(P3)代BMSCs生长曲线。取P4代细胞分为3组给予不同诱导条件,分别给予含20 ng/ml的bFGF和20 ng/ml EGF的无胎牛血清(A组)、10 ml/L胎牛血清(B组)及100 ml/L胎牛血清(C组)的DMEM/F-12培养液进行诱导,倒置显微镜观察细胞的形态变化,诱导6 d时免疫组织化学法检测细胞内神经元特异性烯醇化酶(NSE)及胶质纤维酸性蛋白(GFAP)的表达,台盼蓝染色检测各组细胞的活力。结果:BM-SCs经3-4次传代培养后形态大致呈单一的长梭形或扁平形,流式细胞鉴定显示CD90阳性,CD45阴性;细胞生长曲线近似呈"S"形;诱导后可见细胞胞体收缩,呈双极、多极并伸出突起;诱导6 d时3组活细胞率分别为:86.57%、95.29%、97.32%;免疫组化各组均见NSE、GFAP表达,3组NSE阳性率高于GFAP,A组NSE阳性率高于B、C组,差异具有统计学意义(P<0.01),C组NSE阳性率高于B组,差异具有统计学意义(P<0.01),A组GFAP阳性率低于B、C组,差异具有统计学意义(P<0.01),C组GFAP阳性率高于B组,差异具有统计学意义(P<0.01)。结论:bFGF联合EGF可诱导BMSCs向神经细胞分化,在无血清条件下趋向于向神经元分化,在高浓度血清条件下趋向胶质细胞分化。     

Differential effects of epidermal growth factor (EGF) receptor ligands on receptor binding,downstream signalling pathways and DNA synthesis in hepatocytes

Hepatocytes are responsive to mitogenic effects of several ligands acting via EGFR. Studying primary cultures of rat hepatocytes, we found that, as compared to EGF, HB-EGF had a markedly higher affinity of the EGFR, while AR and TGFα had lower affinity. HB-EGF was also more potent compared to the other growth factors regarding phosphorylation of EGFR, Shc, ERK1/2 and Akt. All ligands induced phosphorylation of ErbB2, indicating receptor heterodimerization. TGFα, despite having much lower receptor affinity, was about equally potent and efficacious as HB-EGF as a stimulator of DNA synthesis. In contrast, EGF had relatively high affinity but markedly lower efficacy in stimulation of DNA synthesis. The results suggest that amplifying and/or inhibitory mechanisms may modulate the mitogenic responses downstream of the initial signalling steps, and that this may affect the effects of the EGFR ligands differentially.     

A nuclear localization signal in the matrix of spleen necrosis virus (SNV) does not allow efficient gene transfer into quiescent cells with SNV-derived vectors

A major limitation in gene therapy for vectors derived from Moloney murine leukemia virus (MLV) is that they only deliver genes into dividing cells. In this study, a careful comparison of spleen necrosis virus (SNV)-derived vectors with MLV and human immunodeficiency virus (HIV)-1 retroviral vectors indicated that SNV vectors can deliver genes 4-fold more efficiently than MLV vectors into aphidicolin-arrested cells, although at a 25-fold lower efficiency than HIV-1-derived vectors. Furthermore, the addition of a NLS in the SNV matrix (MA) that mimics the one located in HIV-1 MA did not increase the ability of SNV vectors to transfer genes into arrested cells. Also, we found that the RD114 envelope was able to pseudotype SNV viral particles in a very efficient manner.     

Differential effect of epidermal growth factor on serous and mucous cells in porcine airway submucosal gland

Using a patch-clamp technique, we found that the fresh porcine submucosal gland acinar cells contained two functionally distinct cell populations, i.e. physiologically relevant concentration of acetylcholine (ACh, 30 nM) induced two distinct patterns of electric response in tracheal gland acinar cells. One was characterized by an outstanding oscillatory Cl(-)-current activity, and the other was with poor Cl(-)-current response but with a comparable K(+)-current. We examined the effect of epidermal growth factor (EGF) on the ACh-induced electric responses in these cells. EGF affected only the latter (K(+)-prominent) cell type to potentiate significantly the ACh-induced K(+)-current. An immunohistochemistry revealed that the receptor for EGF was identified preferentially on the mucous, but not serous, cells. Genistein, one of the tyrosine-kinase inhibitors, abolished the augmentation effect of EGF on the ACh-induced current. Thus, we identified the serous cell with a Cl(-)-rich current in response to ACh and the mucous cell with a K(+)-dominant response. Moreover, EGF affected the mucous cells alone to potentiate the ACh-induced electric response. EGF may contribute to the pathophysiological alterations in chronic inflammatory airways both in morphological (mucous cell hypertrophy/hyperplasia) and functional (thick viscous hypersecretion) ways.     

干扰表皮生长因子受体磷酸化过程对乳腺癌的抑制效应

目的 探讨干扰表皮生长因子受体(EGFR)的磷酸化过程对裸鼠乳腺癌移植瘤生长的影响及其作用机制.方法 建立裸鼠乳腺癌移植瘤模型,成型后随机分为Ad5-hSulf1组、Ad5-EGFP组和对照组,干预治疗后,测量计算移植瘤生长率,采用免疫组化法检测各组裸鼠移植瘤hSulf-1、EGFR和p-EGFR阳性表达,采用Western blot法检测各组裸鼠移植瘤hSulf-1、EGFR和p-EGFR蛋白表达.结果 Ad5-hSulf1组裸鼠注射治疗后第14天、21天和28天的肿瘤生长率[(165.9±23.8)％,(172.6±25.9)％,(377.3±30.5)％]明显小于同期的对照组,差异均具有统计学意义(t=12.153,21.247,14.587;P =0.000).Ad5-hSulf1组裸鼠移植瘤p-EGFR阳性表达率(46.7％)和蛋白表达[(52.7±7.4)％]明显低于Ad5-EGFR组和对照组,差异均有统计学意义(x2=8.146,t=7.384,7.587;P =0.004、0.000、0.000).结论 使用hSulf1基因抑制乳腺癌细胞的EGFR磷酸化过程,可产生明显的肿瘤抑制效应,对寻求肿瘤基因治疗的一个很有潜力的靶点具有很好的借鉴参考意义.     

脂多糖通过核因子-κB途径影响腹膜间皮细胞生长及TNF的表达

目的研究脂多糖(LPS)是否通过核因子κB,即IκBα、NF-κBp65途径引起腹膜间皮细胞(peritonealmesothelial cells,PMC)凋亡、抑制细胞生长和诱导肿瘤坏死因子(TNF)的表达。方法胰蛋白酶-EDTA消化法用于PMC的原代培养、传代,经鉴定分组①不同浓度LPS组(正常对照组、0.1mg/L、1.0mg/L、10mg/L、50mg/L、100mg/L);②不同时间组LPS作用于PMC0、1、3、6、12、24h。Hoechst33258染色法检测PMC的凋亡;MTT法检测PMC的生长增殖抑制情况;免疫荧光法检测p65的活性;Western blot检测IκBα的表达;用L929细胞株检测TNF的活性;RT-PCR检测TNFα mRNA的表达。结果LPS抑制PMC生长并诱导凋亡、引起IκBα的降解、p65的核移位;LPS诱导PMC表达TNF,1hTNF-α mRNA达最大值、3hTNF-α活性达最大值。结论LPS可抑制PMC的生长及诱导凋亡;LPS诱导PMC表达TNF-α呈浓度依赖性,在LPS作用早期TNF-α明显升高,随后下降。这一过程中IκBα-NF-κBp65信号途径可能发挥了重要作用。     

Mechanisms of human cytomegalovirus infection with a focus on epidermal growth factor receptor interactions

Human cytomegalovirus (HCMV) is a widespread opportunistic herpesvirus that causes severe diseases in immunocompromised individuals. It has a high prevalence worldwide that is linked with socioeconomic factors. Similar to other herpesviruses, HCMV has the ability to establish lifelong persistence and latent infection following primary exposure. HCMV infects a broad range of cell types. This broad tropism suggests that it may use multiple receptors for host cell entry. The identification of receptors used by HCMV is essential for understanding viral pathogenesis, because these receptors mediate the early events necessary for infection. Many cell surface components have been identified as virus receptors, such as epidermal growth factor receptor (EGFR), which is characterized by tyrosine kinase activity and plays a crucial role in the control of key cellular transduction pathways. EGFR is essential for HCMV binding, signaling, and host cell entry. This review focuses on HCMV infection via EGFR on different cell types and its implications for the cellular environment, viral persistence, and infection.     

Retrospective study on transmissible viral proventriculitis and chicken proventricular necrosis virus (CPNV) in the UK

ABSTRACT

Chicken proventricular necrosis virus (CPNV) is a recently described birnavirus, which has been proposed to be the cause of transmissible viral proventriculitis (TVP). The understanding of the epidemiology of both the virus and the disease is very limited. A retrospective investigation on TVP and CPNV in broiler chicken submissions from the UK from between 1994 and 2015 was performed with the aims of assessing the longitudinal temporal evolution of TVP and CPNV, and to review the histological proventricular lesions in the studied chickens. Ninety-nine of the 135 included submissions (73.3%) fulfilled the TVP-diagnostic criteria, while the remaining 36 submissions (26.7%) displayed only lymphocytic proventriculitis (LP). The first detection of CPNV by PCR dated from 2009. Results showed a rise in the number of both TVP and positive CPNV RT–PCR submissions from 2009 with a peak in 2013, suggesting that they may be an emerging or re-emerging disease and pathogen, respectively. Twenty-two out of the 99 submissions displaying TVP lesions (22%) and four out of the 36 (11%) submissions with LP gave positive CPNV RT–PCR results, further supporting the association between CPNV and TVP and confirming that CPNV is present in a low proportion of proventriculi that do not fulfil the TVP-diagnostic criteria. In addition, intranuclear inclusion bodies were observed in 22 of the submissions with TVP. The vast majority of these cases (21 of 22, 96%) gave negative CPNV RT–PCR results, raising the question of whether a virus other than CPNV is responsible for some of these TVP-affected cases.

RESEARCH HIGHLIGHTS

• TVP and CPNV have been present in British broilers since at least 1994 and 2009, respectively.

• TVP and CPNV seem to be an emerging and re-emerging disease and pathogen, respectively.

• CPNV was detected in proventriculi with both TVP and LP-lesions.

• Viruses other than CPNV may be responsible for some TVP-affected cases.

     

Improvement of cytotoxic effects induced by mitoxantrone on hormone-refractory metastatic prostate cancer cells by co-targeting epidermal growth factor receptor and hedgehog signaling cascades

The results of the present study revealed for the first time the possibility to use a combination of mitoxantrone with gefitinib and cyclopamine for inhibiting the growth of epidermal growth factor (EGF), sonic hedgehog- (SHHNp), and serum-stimulated androgen-sensitive LNCaP-C33 and androgen-independent (AI) LNCaP-C81, DU145 and PC3 prostate cancer (PC) cells. The supra-additive anti-proliferative effects of drugs were mediated via a blockade of the PC3 cells in the G₁ and G₂M phases of the cell cycle. Importantly, the combination of mitoxantrone plus gefitinib and/or cyclopamine also caused a higher rate of apoptotic death of PC cells including enriched fraction of CD44^high PC3 cell subpopulation as compared to the individual agents or bi-combination of drugs. The cytotoxic effects induced by mitoxantrone, gefitinib and cyclopamine on PC3 cells appear to be at least partly mediated through the depolarization of the mitochondrial membrane, release of cytochrome c into the cytosol, hydrogen peroxide production and activation of caspase cascades. These findings indicate that the simultaneous blockade of EGF–EGFR and sonic hedgehog tumorigenic signaling cascades may represent a promising strategy for improving the efficacy of current mitoxantrone-based therapies against incurable AI and metastatic PCs in the clinics.     

慢性乙肝患者外周血单个核细胞TRAIL受体表达及其临床意义

目的探索慢性乙肝患者外周血单个核细胞(PBMC)肿瘤细胞坏死因子相关的凋亡诱导配体(TRAIL)受体在PBMC凋亡中的作用,及其与机体肝脏损伤的相关性。方法用RT-PCR和流式细胞术检测55例慢性乙肝患者(包括轻度、中度、重度)外周血单个核细胞TRAIL各受体(DR4、DR5、DcR1和DcR2)表达水平,同时检测肝功能相关指标,并进行相关性分析。以30例正常人作为对照。结果诱骗受体DcR1在慢性乙肝患者中的表达显著低于对照组(P<0.05)。DcR1的表达随慢性乙肝病情的加重而逐渐降低。慢性乙肝患者的DcR1表达与转氨酶(ALT)呈显著负相关,与血清白蛋白成显著正相关。结论慢性乙肝患者外周血单个核细胞DcR1表达下调可能是其细胞凋亡增加的机制之一,且DcR1表达情况可从一定程度上反映肝脏的损伤程度。     

Contribution of tumor necrosis factor α and interleukin-1 α on the production of macrophage inflammatory protein-2 in response to respiratory syncytial virus infection in a murine macrophage cell line,RAW264.7

The production of several inflammatory cytokines, such as murine macrophage inflammatory protein-2 (MIP-2), tumor necrosis factor (TNF), and interleukin (IL)-1, was investigated in response to respiratory syncytial virus (RSV) infection in a murine macrophage cell line, RAW264.7, with special reference to mutual relation of their productions. The kinetics of MIP-2 production showed a trend for a biphasic pattern, that is, MIP-2 levels became detectable from 2 h postinfection (p.i.) and increased markedly until 8 h p.i. Thereafter, this level fell to the same level until 16 h p.i. and then increased again. TNF α was also detectable at 2 h p.i. and then increased sharply until 8 h p.i., when the peak level attained. Compared with the levels of MIP-2 and TNF α, that of IL-1 α/β, especially IL-1 β, was lower (ng versus pg/ml order). The presence of anti-TNF α or anti-IL-1 α antibody did not influence the early phase of MIP-2 production but significantly inhibited the late phase, suggesting that MIP-2 is induced by the combined effects of RSV infection via direct induction and indirectly after initial induction of TNF α and IL-1 α productions. Although RSV-infected RAW264.7 cells had no alteration inviability compared with mock-infected control, these data demonstrate that RSV is a potent inducer of inflammatory cytokines by direct induction and indirectly via the initial production of other cytokines. J. Med. Virol. 53:145–149, 1997. © 1997 Wiley-Liss, Inc.