脊椎动物Cyclophilin A肽基脯氨酰顺反异构酶活性及遗传变异分析

Cyclophilin A(简称CypA)由PPIA(Peptidylprolyl isomerase A)基因编码,是典型的Cyclophilin家族蛋白,具有肽基脯氨酰顺反异构酶活性,在蛋白质的折叠和转运、信号转导、炎症、免疫调节、细胞凋亡及病毒复制等生物学过程中发挥着重要作用。本研究重点探讨了不同脊椎动物CypA的肽基脯氨酰顺反异构酶活性及其遗传变异。根据Gen Bank数据库PPIA基因的序列信息,克隆了脊椎动物的PPIA基因并构建其原核表达载体,其中鼠耳蝠(Myotis davidi)和绿头鸭(Anas platyrhynchos)的PPIA基因序列为首次报道。利用大肠杆菌表达GST-Cyp A融合蛋白并进行亲和层析,切除GST标签后再进行分子筛层析,获得纯化的CypA蛋白。利用胰糜蛋白酶偶联法测定CypA的肽基脯氨酰顺反异构酶活性,发现12种脊椎动物CypA的肽基脯氨酰顺反异构酶活性无显著差异。同时,通过一系列遗传变异和分子进化分析,发现12种脊椎动物CypA的酶活位点、CsA结合位点等重要功能域的氨基酸序列完全一致,而且其结构和在染色体中的基因定位也非常保守。研究结果表明,脊椎动物CypA的关键功能域高度保守,这是CypA维持其酶活及生物学功能的有力保障。

人类cyclophilin A基因cDNA的克隆和序列测定

目的:克隆人类环孢霉素A受体亚型cyclophilinA(CypA)基因,对该基因进行序列测定。方法:利用EST重叠序列拼排技术,设计特异性CypA引物,以人外周血白细胞总RNA为模板,进行RT-PCR扩增,纯化PCR产物,装pGEM-T载体,进行DNA序列测定。结果:成功克隆了人类Cyp A基因cDNA序列的开放阅读框,经DNA序列测定证实序列正确。结论:通过克隆人CypA基因,并克隆人pGEM-T载体,为下一步的基因表达和功能研究奠定了实验基础。

cyclophilin A基因多态性及其促炎活性在冠心病中的作用

目的探讨cyclophilin A基因多态性与冠心病的相关性及cyclophilin A的促炎活性在冠心病中的作用。方法抽取冠心病患者200例,正常体检者200例作为对照组。采用硫化修饰引物结合Pfu聚合酶荧光定量PCR的方法检侧各组cyclophilin A 1 460位点的等位基因及基因型频率。酶联免疫吸附法测定各组血浆cy-clophilin A、IL-6、TNF-α和IL-10的水平。结果 cyclophilin A 1 460位点上有3种基因型,即AT,AA和TT型。冠心病组AA基因型频率显著高于对照组,且冠心病组A等位基因频率高于对照组。冠心病组血浆cyclophilin A水平明显高于正常对照组,炎症因子IL-6和TNF-α水平也高于对照组,抗炎因子IL-10低于对照组。冠心病患者经PCI手术后血浆cyclophilin A水平及血浆TNF-α和IL-6水平均逐渐降低,而IL-10则逐渐回升。结论 cyclo-philin A 1 460位点A等位基因可能是冠心病发病的危险因素;cyclophilin A血浆水平可间接反映机体的炎症状态,用于冠心病的病情监侧。

Cyclophilin A affects Bcl-2 and Bax expression following beta-amyloid fragment 25-35-induced injury to PC12 cells

BACKGROUND： Cyclophilin A can protect neurons against oxidative stress. OBJECTIVE： To investigate the effect of cyclophilin A on Bcl-2 and Bax protein expression in pheochro-mocytoma （PC12） cells treated with beta-amyloid fragment 25-35 （Aβ25-35）, and to verify the protection pathway of cyclophilin A. DESIGN, TIME AND SETTING： The initial experiment was performed at the Laboratory of Department of Neurology, First Clinical College, China Medical University from November 2006 to July 2007. MATERIALS： PC12 cells were cultured at the Cell Center of Peking Union Medical College. Aβ25-35 （Sigma, USA）, antibodies of Bcl-2 and Bax （Wuhan Boster, China）, and recombinant human cyclophilin A （Biomol, USA） were used in this study. METHODS： PC12 cells were divided into three groups. Cells in the control group were incubated in culture medium. Cells in the Aβ25-35 injury group were incubated in medium containing a final concentration of 10 μmol/L of Aβ25-35. Cells in the cyclophilin A group were incubated in medium containing a final con-centration of 10 nmol/L of cyclophilin A for 30 minutes, and then treated with 10 μmol/L Aβ25-35. MAIN OUTCOME MEASURES： After 24 hours of culture, immunohistochemistry was used to detect Bcl-2 and Bax expression in PC12 cells. Annexin-V flow cytometry was employed to measure the apoptosis rate of PC12 cells. The MTT method was applied to examine the survival rate of PC12 cells. RESULTS： Bcl-2 expression decreased, whereas Bax expression increased in PC12 cells treated with Aβ25-35 （t = 2.277, 5.957, P 〈 0.05）. However, in PC12 cells treated with Aβ25-35 and cyclophilin A, Bcl-2 expression increased and Bax expression decreased （t = 4.497, 2.531, P 〈 0.05）. The survival rate of PC12 cells significantly decreased and the apoptosis rate increased （t=8.509, 22.886, P 〈 0.05） following Aβ25-35 treatment. Cyclophilin A enhanced the survival rate of PC12 cells to Aβ25-35-induced apoptosis （t = 4.895, 10.042, P 〈 0.05）. CONCLUSION： Cyclophilin A can increase Bcl-2 expression and decrease Bax expression in PC12 cells treated with Aβ25-35, which indicates that cyclophilin A has a protective effect on Aβ25-35-induced injury to PC12 cells.

Caveolin-1结合Cyclophilin A改善大鼠血管平滑肌细胞胆固醇蓄积

观察caveolin-1和cyclophilin A在血管平滑肌细胞荷脂过程中的表达变化及其对细胞内胆固醇蓄积的影响。实验采用Western-blot、免疫荧光法分别定量,定位检测caveolin-1和cyclophilin A蛋白的表达;油红O染色观察细胞内脂滴的形成情况;高效液相检测细胞内外总胆固醇含量;免疫共沉淀检测caveolin-1和cyclophilin A相互作用。结果显示,随着荷脂时间延长,caveolin-1和cyclophilin A的蛋白表达逐渐减弱;细胞内脂滴形成逐渐增多,细胞内总胆固醇含量不断增加;caveolin-1和cyclophilin A在大鼠血管平滑肌细胞中相互结合,并且cyclophilin A活性抑制后,与caveolin-1结合能力减低,而细胞内胆固醇含量增加。这提示,caveolin-1和cyclophilin A在血管平滑肌细胞内可相互结合,并参与改善细胞内胆固醇蓄积。

Correlation of serum cyclophilin A and monocyte chemoattractant protein-1 levels with carotid atherosclerosis in patients with acute cerebral infarction

Objective:To study the correlation of serum cyclophilin A (CyPA) and monocyte chemoattractant protein-1 (MCP-1) levels with carotid atherosclerosis in patients with acute cerebral infarction.Methods: 106 patients with acute cerebral infarction who were hospitalized in our hospital between July 2011 and August 2015 were selected as observation group, and 50 cases of healthy persons who received physical examination in our hospital during the same period were selected as normal control group. The serum CyPA and MCP-1 contnets in two groups were determined. According to the median of CyPA and MCP-1 contents in observation group, they were divided into high CyPA group and low CyPA group as well as high MCP-1 group and low MCP-1 group, 53 cases in each group. Contents of lipid metabolism indexes and carotid atherosclerosis illness-related indicators were compared between acute cerebral infarction patients with different CyPA and MCP-1 contents.Results:Serum CyPA and MCP-1 contents in observation group were significantly higher than those in control group. Serum TC, LP(a) and LDL-C contents in high CyPA group and high MCP-1 group were higher than those in low CyPA group and low MCP-1 group while HDL-C contents were lower than those in low CyPA group and low MCP-1 group. Serum CysC, Hcy and UA contents in high CyPA group and high MCP-1 group were higher than those in low CyPA group and low MCP-1 group.Conclusion: Serum CyPA and MCP-1 contents in patients with acute cerebral infarction are higher than those in normal population, and the contents of CyPA and MCP-1 are positively correlated with the degree of carotid atherosclerosis.

普通小麦-簇毛麦6VS／6AL易位系cyclophilin基因的克隆与序列分析

利用RT-PCR的方法从普通小麦-簇毛麦6VS／6AL易位系克隆到1个cyp基因，命名为Ta-Hv-cyp。该基因全长为599bp，编码1条171个氨基酸残基的多肽，具有保守的功能位点W128和胞质型CyP蛋白特有的插入序列KSGKPLH48-54。BLAST分析表明，推导的Ta-Hv-CyP蛋白分别与小麦、水稻、玉米、拟南芥的胞质型CyP具有98％，88％，85％和80％的氨基酸序列一致性。构建的进化树显示，推导的Ta-Hv-CyP蛋白与单子叶植物胞质型CyPs的亲缘关系较近。

Protective effect of cyclophilin A against Alzheimer＇s amyloid beta-peptide （25-35）-induced oxidative stress in PC12 cells

Background β-amyloid peptide （Aβ） is considered responsible for the pathogenesis of Alzheimer＇s disease （AD）. Possible mechanisms underlying Aβ-induced neuronal cytotoxicity include excessive production of reactive oxidative species （ROS） and apoptosis. Cyclophilin A （CypA）, exhibits antioxidant properties and protects neurons against oxidative stress induced injury. This study was conducted to demonstrate whether CyPA added to cultured PC12 cells could alleviate Aβ-induced oxidative stress and protect them from apoptosis.Methods PC12 cells were pre-incubated for 30 minutes with recombinant human cyclophilin A （rhCyPA） in 0.1 nmol/L, 1.0 nmol/L, 10 nmol/L and 100 nmol/L and then incubated with 10 μmol/L Aβ25-35. In every group, cell viability, apoptotic morphology, apoptotic rate, intracellular ROS accumulation, the activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） of PC12 cells and mitochondrial transmembrane potential were detected. Subsequently, the expression of the active form of caspase-3 was determined by Western blotting.Results It was shown that cultures treated with 1.0 nmol/L, 1U nmol/L or 100 nmol/L rnL, rhCyPA＋Aβ25-35 had significantly higher cell viability and a lower rate of apoptosis compared with the cultures exposed only to Aβ25-35. In addition, rhCyPA attenuated Aβ25-35-induced overproduction of intracellular ROS and Aβ25.35-induced a decrease in activity of the key antioxidant enzymes SOD and GSH-Px. Furthermore, rhCyPA also attenuated Aβ25.35-induced mitochondrial dysfunction and the activation of caspase-3.Conclusion CyPA may act as an ROS scavenger, and prevent Aβ25-35-induced neurotoxicity through attenuating oxidative stress induced by Aβ25-35.

日本血吸虫Sj CyclophilinA基因的克隆、表达及其生物学功能研究

【目的】克隆和表达了日本血吸虫CyclophilinA(Sj CyPA)编码基因cDNA,分析其在日本血吸虫不同发育阶段虫体的表达情况,评估该重组抗原在小鼠体内诱导的抗血吸虫免疫保护效果。【方法】从实验室构建的7天童虫消减cDNA文库中,PCR扩增一EST序列的基因全长cDNA,提交到NCBI,登录号为GQ403666。应用荧光实时定量PCR分析该基因在日本血吸虫不同发育阶段虫体的表达情况,以pET28a(+)为载体构建重组表达质粒,并在大肠杆菌中表达。诱导、表达、纯化和复性重组蛋白,测定其PPIase活性。利用Western blot检测重组蛋白的抗原性。以重组抗原免疫小鼠,评估其对小鼠诱导的免疫保护效果。【结果】PCR获得了Sj CyPA编码基因的全长cDNA,其开放阅读框为519bp。荧光实时定量PCR分析表明,该基因在13d童虫表达量最高,为童虫期高表达基因。构建了重组表达质粒pET28a(+)-Sj CyPA,并在大肠杆菌中成功表达。复性重组蛋白具有PPIase活性。Western blot试验显示该重组蛋白具有良好的抗原性,在小鼠免疫试验中,与空白对照组比较,免疫组小鼠获得18.72%的减虫率和44.6%的肝脏减卵率。【结论】获得了日本血吸虫童虫期高表达的Sj CyPA基因的全长cDNA,成功构建了Sj CyPA原核重组表达质粒,在大肠杆菌中成功表达,纯化复性得到有PPIase活性的Sj CyPA重组蛋白,并证实该重组抗原在小鼠体内诱导产生了部分免疫保护效果。

Cyclophilin A与免疫相关疾病关系的研究进展

亲环蛋白A(Cyclophilin A,CypA)是免疫抑制剂环孢菌素A(Cyclosporine A,CsA)的体内受体。它是目前所知的人类亲环素(Cyps)家族成员中占细胞溶质的量最大的蛋白,且是Cyps家族中最重要的一员,在生物体中广泛表达,发挥重要的生物学作用。首先,CypA本身被认为具有蛋白质的折叠、转运、修复、细胞信号转导和免疫调节等作用;其次,CypA与CD147之间的趋化因子样作用与多种疾病关系密切。研究发现其在多种疾病发生发展过程中表达变化,如炎症、肿瘤、艾滋病和丙型肝炎等免疫相关疾病。CypA有可能成为人类某些免疫相关疾病早期诊断、预防和治疗的重要分子靶标。因此,CypA以成为医学研究中的热点,人们希望通过对其深入的了解为这些疾病的治疗提供新的思路、策略和方法。

Cyclophilin A在心脑血管疾病方面的研究进展

亲环素A(cyclophilinA,CyPA)是一种胞质蛋白,属于亲免素家族(Cyclophilins)成员。它广泛存在并且大量表达于各种组织中,高度保守,具有肽脯氨酰顺反异构酶活性,能够参与多种信号转导途径。亲环素A具有很多生物学功能,包括血管疾病和免疫调节、肿瘤发生等。本文就CyclophilinA蛋白在心脑血管疾病中的研究进展进行综述。

Study of Structural Stability of Cyclophilin A by NMR and Circular Dichroism Spectra

The structural stability of cyclophilin A （CypA） was investigated using H/D exchange and temperature coefficients of chemical shifts of amide protons, monitored by 213 heteronuclear NMR spectroscopy. Amide proton exchange rates were measured by H/D exchange experiments for slow-exchange protons and measured by SEA （Solvent Exposed Amides）-HSQC experiments for fast-exchange protons. Temperature coefficients of chemical shifts and hydrogen exchange rates of amide protons show reasonably good correlation with the protein structure. Totally, 44 out of 153 non-proline assigned residues still exist in 86 d of hydrogen-deuterium exchange at 4 ℃, suggesting that CypA structure should be highly stable. Residues in secondary structures of α2, β1, β2, β5, β6 and β7 might constitute the hydrophobic core of the protein. The change in free energy of unfolding （ △Gu^H2O ） of CypA was estimated to be （21.99± 1.53） kJ·mol^-1 by circular dichroism （CD）. The large free energy change is also an indicator of the high structural stability.

Characterization of a Cyclophilin cDNA from Soybean Cells

A cDNA clone encoded for cyclophilin (GmCyp1) was isolated by RT-PCR method from suspension-cultured soybean (Glycine max L.) cells. The deduced amino acid sequence was 91% identical to a kidney bean cyclophilin in the open reading frame of the gene. Results from Southern blotting analysis suggests that the GmCyp1 belong to a small gene family in soybean cells. The time course of GmCyp1 mRNA accumulation upon treatment of elicitor from yeast extract did not show significant change in the time period examined. The data suggest that the GmCyp1 was not regulated much by biotic factors. A possible role of the cyclophilin in the plant-pathogen interaction was discussed.

Cyclophilin A binds to AKT1 and facilitates the tumorigenicity of Epstein-Barr virus by mediating the activation of AKT/mTOR/NF-κB positive feedback loop

The AKT/mTOR and NF-κB signalings are crucial pathways activated in cancers including nasopharyngeal carcinoma(NPC), which is prevalent in southern China and closely related to Epstein-Barr virus(EBV) infection.How these master pathways are persistently activated in EBV-associated NPC remains to be investigated. Here we demonstrated that EBV-encoded latent membrane protein 1(LMP1) promoted cyclophilin A(CYPA) expression through the activation of NF-κB. The depletion of CYPA suppressed cell proliferation and facilitated apoptosis.CYPA was able to bind to AKT1, thus activating AKT/mTOR/NF-κB signaling cascade. Moreover, the use of mTOR inhibitor, rapamycin, subverted the activation of the positive feedback loop, NF-κB/CYPA/AKT/mTOR. It is reasonable that LMP1 expression derived from initial viral infection is enough to assure the constant potentiation of AKT/mTOR and NF-κB signalings. This may partly explain the fact that EBV serves as a tumor-promoting factor with minimal expression of the viral oncoprotein LMP1 in malignancies. Our findings provide new insight into the understanding of causative role of EBV in tumorigenicity during latent infection.

CyclophilinA对荷脂细胞胆固醇流出的影响

目的观察cyclophilinA在ox—LDL诱导的巨噬细胞荷脂过程中的蛋白表达对细胞内胆固醇流出的影响。方法实验采用荷脂细胞模型，以Westernblot法检测cyclophilinA蛋白的表达改变，高效液相色谱法检测细胞内胆固醇含量的变化，放射性同位素法检测细胞内胆固醇流出情况。结果75rng／Lox—LDL与RAW264.7细胞共同孵育48h后．cyclophilinA的蛋白表达减弱，48、72h分别较未处理组下降了54．5％±6．3％、59．8％±5．9％，差异有显著性（P〈0．05）。细胞内胆固醇流出率未处理组是30．71％±0．71％，ox—LDL处理48、72h后依次下降为12．94％±0．59％、10．77％±0．35％，差异有显著性（P均〈0．05）。结论ox—LDL诱导的RAW264．7细胞荷脂过程中，cyclophilinA的蛋白表达下调与细胞内胆固醇流出密切相关。

The Cyclophilin AtCYP71 Interacts with CAF-1 and LHP1 and Functions in Multiple Chromatin Remodeling Processes

Chromatin is the primary carrier of epigenetic information in higher eukaryotes. AtCYP71 contains both cyclophilin domain and WD40 repeats. Loss of AtCYP71 function causes drastic pleiotropic phenotypic defects. Here, we show that AtCYP71 physically interacts with FAS1 and LHP1, respectively, to modulate their distribution on chromatin. The Ihpl cyp71 double mutant showed more severe phenotypes than the single mutants, suggesting that AtCYP71 and LHP1 synergistically control plant development. Such synergism was in part illustrated by the observation that LHP1 association with its specific target loci requires AtCYP71 function. We also demonstrate that AtCYP71 physically interacts with FAS1 and is indispensable for FAS1 targeting to the KNAT1 locus. Together, our data suggest that AtCYP71 is involved in fundamental processes of chromatin assembly and histone modification in plants.

Evaluation of non-covalent interaction between Seryl-Histidine dipeptide and cyclophilin A using NMR and molecular modeling

Seryl-Histidine dipeptide(Ser-His) has been previously reported to be capable of cleaving DNAs and carboxyl esters,as well as proteins.The protein cleavage mechanism has not been addressed yet.As an initial step of protein cleavage activity,the non-covalent binding affinity of Ser-His for proteins is a crucial prerequisite.In this work,we took cyclophilin A(CyPA) as a substrate protein,and evaluated the non-covalent interaction between CyPA and Ser-His using a combination of NMR spectroscopy and molecular modeling approach.Two independent Ser-His binding sites on CyPA were detected using 15N-1H heteronuclear single-quantum coherence(HSQC) spectra.Each binding site binds one Ser-His molecule.Dissociation constants,Kd1 and Kd2,were estimated to be 2.07 and 6.66 mmol/L,respectively,indicative of the weak non-covalent interaction between Ser-His and CyPA.Based on molecular modeling results,we suggest that both the α-amino and the side chain hydroxyl group of Ser-His are crucial for the non-covalent interaction between Ser-His and CyPA.This work sheds light on the molecular mechanism of Ser-His and its analogues cleaving proteins.

Cyclophilin D-induced mitochondrial impairment confers axonal injury after intracerebral hemorrhage in mice

The mitochondrial permeability transition pore is a nonspecific transmembrane channel.Inhibition of mitochondrial permeability transition pore opening has been shown to alleviate mitochondrial swelling,calcium overload,and axonal degeneration.Cyclophilin D is an important component of the mitochondrial permeability transition pore.Whether cyclophilin D participates in mitochondrial impairment and axonal injury after intracerebral hemorrhage is not clear.In this study,we established mouse models of intracerebral hemorrhage in vivo by injection of autologous blood and oxyhemoglobin into the striatum in Thy1-YFP mice,in which pyramidal neurons and axons express yellow fluorescent protein.We also simulated intracerebral hemorrhage in vitro in PC12 cells using oxyhemoglobin.We found that axonal degeneration in the early stage of intracerebral hemorrhage depended on mitochondrial swelling induced by cyclophilin D activation and mitochondrial permeability transition pore opening.We further investigated the mechanism underlying the role of cyclophilin D in mouse models and PC12 cell models of intracerebral hemorrhage.We found that both cyclosporin A inhibition and short hairpin RNA interference of cyclophilin D reduced mitochondrial permeability transition pore opening and mitochondrial injury.In addition,inhibition of cyclophilin D and mitochondrial permeability transition pore opening protected corticospinal tract integrity and alleviated motor dysfunction caused by intracerebral hemorrhage.Our findings suggest that cyclophilin D is used as a key mediator of axonal degeneration after intracerebral hemorrhage;inhibition of cyclophilin D expression can protect mitochondrial structure and function and further alleviate corticospinal tract injury and motor dysfunction after intracerebral hemorrhage.Our findings provide a therapeutic target for preventing axonal degeneration of white matter injury and subsequent functional impairment in central nervous diseases.