Role of heat shock protein 90 and tubulin in oxidative stress preconditioning

AIM:To find the role of heat shock protein 90 （HSP90） and tubulin in oxidative stress preconditioning in HepG2 cells. METHODS:The different doses of H2O2 were used to induce cell injury in HepG2 cells. MTT assay, Western blotting and confocal laser microscopy were also used. RESULTS:MTT colorimetry showed that preconditioning (50 mmo1/L H2O2) provided a temporary resistance against subsequent oxidative stress (500 mmol/L H2O2). Western blotting demonstrated that preconditioning increased the levels of HSP90 and tubulin in HepG2 cells, and lessen the declining of HSP90 and tubulin after stress. Tubulin and HSP90's colocalizations in cells with different doses of H2O2 were also observed under laser scanning confocal microscope. CONCLUSION:Tubulin might play important role in oxidative stress preconditioning in HepG2 cells by combining with HSP90.     

Glycogen synthase kinase-3 beta overexpression enhances tau protein phosphorylation and attenuates tubulin acetylation in SH-SY5Y cells

AIM: To construct GSK3β-overexpressed SH-SY5Y cells and to observe the effects of GSK3β-overexpression on tau protein phosphorylation and tubulin acetylation in SH-SY5Y engineered cells. METHODS: The cDNA of GSK3β construct was subcloned into mammalian expression vector pBudCE4.1. The integrity of the GSK3β construct was confirmed by sequence analysis. GSK3β was transiently transfected into SH-SY5Y cells using Lipofectamine2000. Western blotting was used to measured protein levels of GSK3β and phosphorylating GSK3β, as well as, the total tau and phosphorylated tau protein and acetylated tubulin. RESULTS: 36 h after transfection, the levels of GSK3β and phosphorylating GSK3β in SH-SY5Y cells were significantly increased compared with non-transfection group and vector group. After 48 h, the levels of phosphorylated tau protein (Ser199/202, Thr231 and Thr205 residues) but not total tau protein were markedly increased in GSK3β-overexpressed SH-SY5Y cells. In addition, the level of acetylated tubulin was lower than that in non- transfection group and vector group. CONCLUSION: The over-expression of GSK3β in SH-SY5Y cells results in robust increases in tau protein phosphorylation at Ser199/202, Thr231 and Thr205 residues, and decreases in tubulin acetylation.     

The proteome research of human lens epithelial cells by two-dimensional gel electrophoresis and mass spectrometry

AIM: To establish the techniques in the proteome research of human lens epithelial cells,including the techniques of two-dimensional electrophoresis and mass spectrometry.METHODS: Total protein of cultured human lens epithelial cells was extracted with two kinds of different methods.The proteins were separated using immobilized pH gradients 2-DE and visualized by silver staining.The digitized images obtained by GS-800 scaner were then analyzed with PDQuest software in order to establish the differential expression profiles.The differential expressed protein spots were cut from the gels using proteomework spot cutter and subjected to in-gel digestion with trypsin.The digested peptide separation was conducted by a Finnigan LCQ MS coupled with a Surveyor HPLC system. RESULTS: A high resolution and reproducible 2-ED image was successfully obtained.The maps of 2-DE showed that lens proteins were in the section of pH 4-7 which the relative molecular weight was 17-72 kD.Relative molecular weight of more abundant proteins was localized at 19-50 kD,as well as the isoelectric points were found to lie between PI 5-7.Two of these proteins were identified by mass spectrometry and database queries.CONCLUSION: A stable protein maps of human lens epithelial cells is constructed.The technique will be used in human lens research to characterize physiological processes and diseases.     

A 3D cell culture system to study epithelial-mesenchymal transition and drug resistance of lung cancer

AIM To explore the molecular mechanism of transforming growth factor-β1 （TGF-β1）-induced epithelial-mesenchymal transition （EMT） and cisplatin resistance in three-dimensionally cultured lung cancer cells. METHODS Under three-dimensional culture condition, the morphological changes and protein expression changes of human non-small-cell lung cancer 95D cells were observed by inversed fluorescence microscopy, scanning electron microscopy, laser scanning confocal microscopy and Western blot before or after TGF-β1 stimulation. The cisplatin sensitivity was determined by MTT assay. RESULTS Under the three-dimensional culture condition, the structure of 95D cell spheroids after TGF-β1 stimulation collapsed, the cells were dispersed and migrating, and the spheroids merged with each other. The results of laser confocal microscopy showed that E-cadherin protein expression in the 95D cells did not changed after TGF-β1 stimulation, and the protein expression of N-cadherin and vimentin was significantly up-regulated. The results of Western blot showed that the expression of E-cadherin was down-regulated after TGF-β1 stimulation, and the protein levels of N-cadherin, vimentin, phosphorylated AKT and phosphorylated mTOR were up-regulated. LY294002 and rapamycin reversed TGF-β1-induced expression of the above proteins. The results of MTT assay showed that TGF-β1 reduced the sensitivity of three-dimensionally cultured 95D cells to cisplatin, while LY294002 and rapamycin reversed the cisplatin resistance of the 95D cells stimulated by TGF-β1. CONCLUSION TGF-β1 induces the EMT and cisplatin resistance of three-dimensionally cultured lung cancer cells through the activation of PI3K/AKT/mTOR signaling pathway.     

Effects of ginsenoside Rb1 on proteome from hippocampus of rats with epilepsy induced by Coriaria lactone

AIM: To explore the mechanism of development of Coriaria lactone (CL)-induced epilepsy and the neuroprotective effects of ginsenoside Rb1 (GRb1) on the process of epilepsy by identifying the proteins related to CL and GRb1 in rat hippocampus with two-dimensional electrophoresis (2-DE) technology.METHODS: The rat model of epilepsy was induced by CL. The rats in control group, CL epileptic group and GRb1 +CL epileptic group were decapitated and the hippocampus were collected. Two-dimensional electrophoresis was applied to separate the proteins from each group. Analysis of 2-DE maps was used to determine differential expression of proteins by ImageMaster 2D Platinum 5.0, and some differentially expressed protein spots were picked up for further identification by matrix-assisted laser sorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS).RESULTS: Six proteins were successfully identified. Among these, the expression of brain creatine kinase, endophilin-A1 and UPF0628 protein C10orf96 homolog was lower in GRb1+CL epileptic group than those in CL epileptic group. The expression of cytochrome P-450, phosducin-like protein and bridging integrator 3 protein was lower in GRb1+CL epileptic group than those in control group.CONCLUSION: The protein expression profiles are significantly different among control group, CL epileptic group and GRb1+CL epileptic group. The identified proteins may be related to the neuroprotective effects of GRb1. Among these, brain creatine kinase, endophilin-A1 and UPF0628 protein C10orf96 homolog may be related to CL-induced seizures.     

橡胶树死皮病黄色体差异表达蛋白的初步分析

橡胶树"死皮病"给橡胶种植业带来严重的危害.为了更好地了解和阐明死皮病发生、发展的分子机制,研究应用双向凝胶电泳技术(two-dimensional gel electrophshiya/oresis,2-DE)比较橡胶树死皮株与健康株胶乳黄色体蛋白质组表达的差异.采用TCA/丙酮沉淀法提取橡胶树死皮株与健康株黄色体蛋白质并采用固相pH梯度(immobjlized pH graalient,IPG)双向凝胶电泳分离两种材料蛋白质,凝胶经银染显色后,用PDQuest图像分析软件进行比较分析、识别差异表达的蛋白质.成功获得橡胶树死皮株与健康株胶乳黄色体的双向凝胶电泳图谱.鉴定出13个蛋白差异点,其中10个上调表达,3个下调表达.并应用质谱技术鉴定了其中部分表达差异的蛋白质点,对渗调蛋白进行功能分析,认为渗调蛋白在死皮株中表现下调的情形可能与死皮病的发生有一定的关系.     

新红星苹果花芽蛋白质提取及双向电泳的改良方法

以新红星苹果花芽为材料,探索适合蛋白质的提取方法及其双向电泳的条件。采用物理和化学2种方法充分裂解植物组织细胞,并用低温操作加入PVP等去除植物大量的酚类物质,最后离心去除不溶性杂质的苹果蛋白质组双向电泳(2-DE)样品制备方法,第1向为ISO-DALT等电聚焦,第2向为垂直平板SDS-PAGE。通过对样品制备、双向电泳参数的选择及染色等方面进行优化,电泳图谱可分辨出蛋白质斑点数在519个以上,蛋白质相对分子质量约为14.0～97.0ku,主要分布为14.0～67.0ku;等电点约为3.5～9.0,主要分布在4.0～7.0。     

Proteomic study of myocardial mitochondria with ischemia/reperfusion injury and pinacidil postconditioning in isolated rat hearts

AIM: To investigate the protective effect of pinacidil postconditioning on rat myocardium suffering ischemia/reperfusion injury by mitochondrial proteomics. METHODS: Langendorff apparatus was used to establish the model of myocardial ischemia/reperfusion injury. Sprague-Dawley rats were randomly divided into 2 groups: pinacidil postconditioning group (Pina group) and ischemia/reperfusion injury group (I/R group). After 20 min of perfusion with K-H solution, the perfusion was suspended for 40-min (global ischemia) follow by 60 min of reperfusion in I/R group. In Pina group at the end of 40 min global ischemia, the isolated hearts were perfused with K-H solution containing pinacidil (50 μmol/L) for 2 min followed 58-min perfusion with regular K-H solution. Total proteins extracted from the mitochondria were applied to the two-dimensional gel electrophoresis (2-DE). The differentially expressed protein spots over 2 times were evaluated by a software. Then they were subjected to in-gel digestion, and analyzed by spectrometry. RESULTS: The expression levels of NDUFA10, NDUFS2 and NDUFV2 were elevated but those of IDHA and ECH1 were decreased in Pina group compared with I/R group. Interestingly, 2 spots in the 2-DE map were identified as ATPase subunit δ. The expression levels of one spot was elevated, while the other was decreased. CONCLUSION: Pinacidil postconditioning may decrease the degree of increased expression levels of NDUFA10, NDUFS2 and NDUFV2, promote the expression of IDHA and ECH1, and induce the phosphorylation of ATPase subunit δ, which may be related to the protective mechanism of pinacidil postconditioning.     

Protective effect of quercetin on rat cardiomyocytes against anoxia/reoxygenation injury is mediated by PKCε signaling pathway

AIM：To investigate whether quercetin (Que) protects cardiomyocytes from anoxia/reoxygenation (A/R) injury through protein kinase C epsilon (PKCε) pathway. METHODS：Primary cardiomyocytes were isolated from neonatal SD rats and exposed to A/R (3 h of anoxia followed by 2 h of reoxygenation) as well as Que and/or εV1-2 (a selective PKCε inhibitor) preconditioning. The expression of PKCε in the cells was detected by Western blotting. The levels of lactate dehydrogenase (LDH) and creatine kinase (CK) in cell culture supernatants, the reactive oxygen species (ROS) and mitochondrial membrane potential in the cells, the opening of mitochondrial permeability transition pore (mPTP) and the cell viability and apoptosis were also measured. RESULTS：The expression of PKCε protein was significantly increased in the cardiomyocytes pretreated with 40 μmol/L Que 72 h before A/R (P<0.01 vs A/R group). Meanwhile, Que preconditioning could increase cell survival rate, decrease ROS production and cell apoptosis, alleviate the loss of mitochondrial membrane potential and inhibit the opening of mPTP induced by A/R injury (P<0.01 vs A/R group). However, pretreatment with Que and εV1-2 attenuated these protective effects of Que (P<0.01 vs Que+A/R group). CONCLUSION：One of the mechanisms underlying the cardioprotective effect of Que might be the increase in PKCε protein expression and the activation of its downstream pathway.     

Identification of proteins involved in insulin stimulation in v ascular smooth muscle cells of SHR rats

AIM:To identify proteins involved in insul in stimulation and the molecular mechanism of proliferation and migration in vas cular smooth muscle cells (VSMCs).METHODS:A series of methods,including 2-D electrophoresis,PDQ uest software analysis of 2-DE gels,peptide mass fingerprinting based on matrix -assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TO F-MS) and SWISS-PROT database searching,were used to separate and identify the differentially expressed proteins.The difference of some proteins was proved by Western blotting.Proliferation and migration of VSMCs treated with insulin wer e also observed.RESULTS:DNA synthesis were increased in VSMCs.［3H］-thymidi ne incorporation in VSMCs from SHR (14.40±0.85) was higher than that in VSMCs from WKY (9.21±0.93,P<0.05).Migration rate of VSMCs from SHR was abou t 1.8 times higher than that in VSMCs from WKY (P<0.05).Image analysis re vealed that averages of protein spots detected were 502±32 and 612±39 in contr ol VSMCs and in cells treated with insulin,respectively.Result of western blo tting confirmed that α-SM protein was down-regulated and matrix Gla,OPN protei ns were up-regulated by insulin stimulation.CONCLUSION:The results suggest that the differential proteomic analysis may be useful to study related proteins involved in insulin-regulated p roliferation in VSMCs.     

盐胁迫下枣叶片蛋白质组差异的分析

【目的】为了探明盐胁迫下枣蛋白表达的差异,【方法】以较耐盐碱的‘七月鲜’枣品种的扦插苗为材料,经过临界浓度(0.60%)的钠盐(NaCl)处理,取其叶片进行蛋白质双向电泳,经ImageMaster 2D分析,【结果】结果表明,处理与对照之间总蛋白的整体分布模式非常相似,在pH 3~10和MW50~90 kD内的蛋白点分布最多,处理与对照之间量变倍数大于1.5倍的差异点有26个,其中6个蛋白受胁迫上调,20个蛋白受胁迫下调。在上调的蛋白质点中,3个点受盐胁迫诱导增加了近4倍,2个蛋白质点相对丰度增加了2倍以上,表现出强烈的盐诱导特性。说明他们可能在枣的抗盐机制中发挥重要作用。在下调的蛋白质点中,2个点相对丰度降低至对照的5倍左右,表现出强烈的盐抑制特性,说明其可能是对盐胁迫比较敏感的2个蛋白质或多肽,并且在枣的抗盐性机制中也发挥比较重要的作用。【结论】在临界浓度钠盐胁迫下,枣叶片蛋白质表达有显著差异。     

桃果实蛋白质双向电泳影响因素的研究

以‘大久保’桃（^{Prunus persica} L.'Okubao'）果实为试材,通过比较不同上样量、不同上样缓冲液、不同平衡缓冲液、不同染色方式等条件下的双向电泳图谱,探讨以上各因素对桃果实双向电泳图谱效果的影响。结果表明考马斯亮蓝染色后的电泳图谱虽然蛋白质点的数量少于银染色后的图谱,但背景较为清晰,适用于蛋白质组分析。采用固相pH梯度17 cm胶条,100 μg蛋白质上样量,样品干粉溶于375 μL含有硫脲、磺基三甲基胺乙内脂3~10的上样缓冲液中,等电聚焦后用含有磷酸三丁酯的平衡缓冲液还原,进行SDS-PAGE,银染色得出的双向电泳图有蛋白点1 209个,纹理较少,适用于桃果实蛋白质组学分析且兼容于下游技术的蛋白质质谱鉴定。     

Sevoflurane preconditioning inhibits brain injury in hypoxic mice

AIM: To observe the effects of sevoflurane preconditioning on brain injury in hypoxic mice and its possible mechanism. METHODS: Male C57BL/6J mice were randomly divided into control (C) group, hypoxia (H) group, 2% sevoflurane preconditioning for 30 min + hypoxia (S1+H) group, 2% sevoflurane preconditioning for 60 min+hypoxia (S2+H) group and 4% sevoflurane preconditioning for 30 min + hypoxia (S3+H) group. The hypoxia model was established by continuous inhalation of (6.5±0.1)% O₂ for 24 h. The sevoflurane preconditioning treatments, S1, S2 and S3, were conducted by inhalation of 2% sevoflurane for 30 min, 2% sevoflurane for 60 min and 4% sevoflurane for 30 min, respectively, with the carrier of (21.0±0.5)% O₂, followed by washout for 15 min and then hypoxia treatment. The histological changes of the hippocampal CA1 area were observed under light microscope and transmission electron microscope (TEM), and serum lactate dehydrogenase (LDH) activity was measured by colorimetric method. Furthermore, the protein levels of erythropoietin (EPO) and vascular endothelial growth factor (VEGF) in brain tissue homogenate were examined by ELISA, and the content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured by microplate reader. RESULTS: After hypoxia for 24 h, cell edema or pyknosis in the hippocampal CA1 area was observed in H group. Sevoflurane preconditioning reduced hypoxic injury, and the cell ultrastructure under TEM was significantly improved in S2+H group. Compared with C group, the serum LDH activity and the levels of EPO, VEGF and MDA in brain tissues were significantly increased in H group, while the activity of SOD and GPx decreased. After sevoflurane pretreatment, the serum LDH activity and the levels of EPO and VEGF in brain tissues were lower than those in H group, and the most significant difference was observed in S2+H group. Moreover, the MDA content and SOD activity decreased, and the GPx activity increased in the sevoflurane preconditioning groups. CONCLUSION: Sevoflurane preconditioning attenuates brain injury in hypoxic mice by regulating antihypoxic protein synthesis and reducing oxidative stress.     

Effect of atorvastatin on ventricular remodeling in spontaneous hypertension rats

AIM：To explore the effect of atorvastatin on cardiac remodeling in spontaneous hypertension rats (SHR).METHODS：Twelve spontaneous hypertension rats were divided randomly into two groups：group of atorvastatin (atorvastatin 50 mg·kg^-1·d^-1) and group of SHR (0.5% mucilage of arabic gum,10 mL·kg^-1·d^-1).Additionally,six male Wistar-Kyoto rats (0.5% mucilage of arabic gum,10 mL·kg^-1·d^-1) were selected as control group.Systolic blood pressure was assessed with the tail-cuff method.After six weeks,entire heart,and left ventricle were weighed.The left ventricular weight index was calculated and myocardial hydroxyproline and collagen protein concentration were measured.The serum high sensitivity CRP (hs-CRP) was measured by nephelometry.The localization of vascular cell adhesion molecule (VCAM) in myocardium was investigated by immunohistochemistry assays.The level of NF-κB mRNA expression was detected with in situ hybridization.Ultrastructure in cardiac muscle was also observed under transmission electron microscope.RESULTS：The expression of myocardial VCAM and NF-κB in SHR group was stronger than that in WHY group.Compared with SHR group,entire heart weight,left ventricular weight,left ventricular weight index,serum hs-CRP,myocardial hydroxyproline and collagen protein concentration was decreased,the expression of myocardial VCAM and NF-κB in SHR group was weaker than that in atorvastatin treatment group.The myocardial pathological change such as incomplete karyotheca in cardiac muscle cells,no clear of transverse striation and the mess in myofibril alignment,and hyperplasy in interstitial collagen fibre were observed in SHR group and these changes were improved in atorvastatin treatment group.CONCLUSION：The cardiac remodeling in SHR is improved by atorvastatin.The molecular mechanism may be related to its down-regulating the expression of VCAM protein and NF-κB and inhibiting myocardial chronic inflammation.     

Comparative proteomics of myocardial mitochondrial proteins in aging rats

AIM:To identify the proteins related to aging in the mitochondria of the heart. METHODS:Mitochondria were isolated from the hearts of adult (10-week) and old (12-month) rats (n=3). Total proteins extracted from the mitochondria were applied to the two-dimensional gel electrophoresis. The differentially expressed protein spots evaluated by a software were subjected to in-gel digestion, and analyzed by the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). ATP content in the heart was also measured. RESULTS:Eighty-four differentially expressed protein spots were observed, and fifteen of them were analyzed by MALDI-TOF- MS. Four proteins including creatine kinase, peroxiredoxin 2, Tu translation elongation factor and isocitrate dehydrogenase were up-regulated and 11 proteins including succinate dehydrogenase, malate dehydrogenase, aconitate hydratase, NADH dehydrogenase, ATP synthase H+ transporting, ATP synthase beta chain, heat shock protein 60, glucose-regulated protein 78, prohibitin, Aldehyde dehydrogenase 2 and voltage-dependent anion channel exhibited down-regulation in the aging group compared to the adult one. ATP content in the heart of old rats was significantly reduced as compared to that in adult rats (n=5, P<0.01). CONCLUSION:Significant changes in the mitochondrial protein expression in the aging heart were identified by the 2-DE electrophoretogram with high resolution and reproducibility. The functions of these identified proteins need to be further investigated.     

苹果叶片总蛋白提取及其双向电泳分析

蛋白质提取方法和电泳条件的建立是蛋白质组学研究中双向电泳分析的关键。通过比较不同提取方法,包括酚/SDS抽提、TCA-丙酮沉淀法、甲醇/醋酸铵沉淀法以及改良HB-酚抽提方法。此外,还优化了样品上样量、等电聚焦程序设置等条件。从所得2-D图谱分离效果来看,改良HB-酚抽提方法所得蛋白点数最多,2-D图谱背景清晰、分离效果好,明显优于其他3种方法。300μg上样量可作为苹果叶片总蛋白2-DE分析的理想的上样量,同时优化了等电聚焦程序,最终得到的2-D图谱分离效果较为理想。该研究的开展也为苹果叶片蛋白质组学后续研究奠定了基础。     

Chutan-Jiedu decoction reverses resistance of lung cancer to gefitinib by processing EMT

AIM: To investigate the mechanism of Chutan-Jiedu decoction (CJD) reversing the resistance of lung cancer to gefitinib via epithelial-mesenchymal transition (EMT) pathway.METHODS: BALB/c nude mice (n=60) were selected to establish lung cancer xenograft model with human lung adenocarcinoma drug-resistant cell line H1975, which were randomly divided into 6 groups (10 mice per group):model group, gefitinib (0.04 g/kg) group, low-dose (13.52 g/kg) CJD group, middle-dose (27.04 g/kg) CJD group, high-dose (54.08 g/kg) CJD group, and combined medication group (27.04 g/kg CJD+0.04 g/kg gefitinib). The mice in each group were treated for 2 weeks before the tumor size and tumor weight were detected for the calculation of the tumor inhibitory rate. The mRNA and protein expression levels of E-cadherin, Snail and vimentin were determined by immunohistochemistry, Western blot and real-time PCR.RESULTS: Compared with model group and gefitinib group, the tumor size and the tumor weight in middle-dose CJD group, high-dose CJD group and combined medication group were decreased significantly (P<0.05). The results of immunohistochemistry, Western blot and real-time PCR showed that the expression of E-cadherin at mRNA and protein levels was increased significantly, while the expression of Snail and vimentin at mRNA and protein levels was decreased significantly (P<0.05).CONCLUSION: The growth of lung adenocarcinoma H1975 xenografts in nude mice is inhibited by CJD. In addition, the resistance of lung cancer to gefitinib is reversed. The mechanism may be related to the regulation of EMT-related protein expression.     

Hypoxic preconditioning increases tolerant ability of old human bone marrow mesenchymal stem cells to oxidative stress injury through AKT pathway

AIM: To investigate the protective effect of hypoxic preconditioning on human bone marrow mesenchymal stem cells (hBM-MSCs), and to provide basic experimental support for more effective autologous stem cell transplantation in aged patients. METHODS: The old hBM-MSCs were subjected to hypoxic preconditioning using a hypoxia incubator chamber for 24 h. The cells were divided into young group, old group and old+hypoxia group (with 24 h hypoxic preconditioning). Hydrogen peroxide (H₂O₂, 300 μmol/L) was applied to simulate the oxidative stress. The cells were treated with 50 μmol/L LY294002 for 2 h to inhibit PI3K/AKT pathway. BrdU incorporation and CCK-8 assay were used for analyzing the cell proliferation and viability. The protein levels of Bax, Bcl-2 and p-AKT were measured by Western blot. RESULTS: BrdU-positive cells, which represented the cell proliferation, and the cell viability were significantly increased in old+hypoxia group compared with old group (P<0.05). The protein level of Bax decreased (P<0.05) and Bcl-2 increased (P<0.05) in old+hypoxia group compared with old group after using 300 μmol/L H₂O₂ simulate. the oxidative stress. The phosphorylation of AKT was enhanced by hypoxic preconditioning in old group (P<0.05). The protective effect of hypoxic preconditioning on the cell survival was decreased after treated with LY294002 (inhibitor of the PI3K/AKT pathway) (P<0.05). CONCLUSION: Hypoxic preconditioning increases the survival and proliferation of old hBM-MSCs by activation of AKT pathway.     

山葡萄花序蛋白质双向电泳技术体系的建立

【目的】为开展山葡萄花序蛋白质组学研究。【方法】以山葡萄(Vitis amurensis Rupr)花序为试材,通过对蛋白质提取方法、裂解液成分、胶条pH梯度的改进,建立了适于山葡萄花序蛋白质组学研究的最佳双向电泳技术体系。【结果】采用酚提取法提取花序蛋白质,用含有硫脲和DTT的裂解液Ⅱ裂解,选用17 cm pH 4～7的IPG胶条在适宜的双向电泳条件下分离,可以获得分辨率高、背景清晰且重复性好的双向电泳图谱,可以检测出1 088个清晰的蛋白点。【结论】酚提取法适于山葡萄花序蛋白质的提取,硫脲和DTT可增强花序蛋白质的溶解性。     

Role of Snail in the renal tubular epithelial-mesenchymal- transition mediated by activator protein-1

AIM: To study the role of Snail in the renal tubular epithelial-myofibroblast transdifferentiation and fibronectin synthesis mediated by activator protein-1. METHODS: The cultured HK2 cells were divided into three groups: normal glucose group (NG), high glucose group (HG) and activator protein-1 (AP-1) inhibited group (AG). Concentration of fibronectin into the culture media was determined by ELISA. The activity of activator protein-1 was assessed with electrophoretic mobility shift assay (EMSA). The protein of E-cadherin and vimentin was determined by immunocytochemistry. RT-PCR was used to detect the mRNA expression of vimentin and Snail. Western blotting was used to detect the protein expression of E-cadherin.RESULTS: Secreted FN level was significantly up-regulated by the stimulation of high glucose (P<0.05), but the level significantly decreased in AP-1 inhibited group than that in high glucose group (P<0.05). AP-1 binding activity was significantly stimulated by high glucose and the inhibitor of AP-1 inhibited high glucose induced AP-1 activation in HK-2. High glucose induced Snail mRNA expression, while the level significantly decreased in AP-1 inhibited group than that in high glucose group (P<0.05). Upon the stimulation with high glucose, the expression of E-cadherin protein decreased markedly (P<0.05), while the level was higher in AP-1 inhibited group than that in high glucose group (P<0.05). Cultured with high glucose, the expression of vimentin mRNA and protein significantly increased (P<0.05), but the level significantly decreased in AP-1 inhibited group than that in high glucose group (P<0.05). CONCLUSION: High glucose induces the expression of Snail through the activation of AP-1. The expression of Snail downregulates E-cadherin expression and induces transdifferentiation of renal tubular cells characterized by vimentin expression and fibronectin synthesis.