FK506的药理学及免疫抑制作用

ＦＫ５０６具有强烈的免疫抑制作用，它通过抑制Ｔ辅助细胞、嗜碱性粒细胞、肥大细胞的早期活化基因的表达，从而抑制ＣＴＬ的克隆扩增和细胞因子的产生。临床研究表明，它能明显延长肝、肾、肺移植存活时间，对自身免疫性疾病如葡萄膜炎有控制病情进展的效果。本文对其药理、免疫抑制作用及近年来的临床应用效果进行综述。     

p300介导组蛋白乙酰化修饰下调PPAR-γ致妊娠期糖尿病小鼠子代心肌细胞糖脂代谢紊乱

目的:阐明妊娠期糖尿病(GDM)对子代心肌细胞糖脂代谢的影响,并探讨其可能的调控机制。方法:雌性昆明小鼠于妊娠中期给予腹腔注射链脲佐菌素(30 mg/kg)建立GDM模型,另设对照(control)组。分娩后F1代饲养至8周,测定随机血糖和空腹血脂等相关指标。利用CO2窒息处死F1代实验小鼠,剖开胸腔后分离心脏组织,用于后续实验。q PCR检测p300及p300/CBP相关因子(PCAF)的mRNA表达水平,q PCR及Western blot检测过氧化物酶体增殖物激活受体γ(PPAR-γ)、葡萄糖转运蛋白4(GLUT-4)及中链酰基辅酶A脱氧酶(MCAD)的mRNA和蛋白表达水平,染色质免疫共沉淀(Ch IP)结合q PCR检测p300与PPAR-γ启动子结合水平及PPAR-γ启动子区域组蛋白H3的乙酰化水平。结果:F1代小鼠血糖和总胆固醇轻度升高(P0.05),甘油三酯、高密度及低密度脂蛋白无明显改变;心肌组织中p300、PPAR-γ、GLUT-4及MCAD表达明显降低(P0.05),PCAF的表达两组间差异无统计学显著性;p300与PPAR-γ启动子结合水平和PPAR-γ启动子区域组蛋白H3的乙酰化水平均明显下降(P0.05)。结论:GDM子代小鼠中p300通过介导组蛋白乙酰化修饰而下调PPAR-γ表达,可能引起心肌细胞糖脂代谢紊乱。     

miR-let-7d通过调控核受体PPARγ促进肺癌细胞的增殖和侵袭

目的:探讨miR-let-7d对肺癌细胞核受体过氧化物酶体增殖物激活受体γ(PPARγ)的调控及对肺癌细胞增殖和侵袭的影响。方法:用生物信息学分析与PPARγ相关的microRNA,通过质粒报告基因验证miR-let-7d的作用靶点;利用Western blot法筛选出PPARγ表达水平低的肺癌细胞株;通过双萤光素酶标记和Western blot法验证miR-let-7d对肺癌细胞中PPARγ表达的调控作用;通过集落形成实验检测miR-let-7d对肺癌细胞增殖能力的调控作用;通过Transwell侵袭实验检测miR-let-7d对肺癌细胞侵袭能力的作用。结果:生物信息学的分析结果证明miR-let-7d可以调控核受体PPARγ的蛋白表达;在核受体PPARγ的3’UTR包含2个功能性的miR-let-7d结合位点;PPARγ是miR-let-7d的直接靶点,miR-let-7d可在蛋白和mRNA水平直接调控PPARγ的表达;miR-let-7d inhibitor通过升高PPARγ的表达促进肺癌细胞的增殖和侵袭能力。结论:miR-let-7d能够通过靶向增加具有抑癌作用的核受体PPARγ的表达水平,抑制肺癌细胞的增殖和侵袭能力。     

番石榴叶总三萜对2型糖尿病大鼠的降血糖和血脂作用

目的: 探讨番石榴叶总三萜(TTPGL)对2型糖尿病大鼠血糖及血脂的影响。方法: 采用高糖高脂饮食加腹腔注射小剂量链脲佐菌素(STZ, 35 mg·kg^-1)方法建立2型糖尿病大鼠模型。将造模成功的糖尿病大鼠随机分为5组:糖尿病模型组,TTPGL低、中、高剂量组(60、120、240 mg·kg^-1),罗格列酮阳性对照组(3 mg·kg^-1)。另取12只正常大鼠设为正常对照组。给药组每天灌胃给药1次,连续给药6周;模型组和正常对照组则给予同体积的生理盐水灌胃。给药6周后,采用葡萄糖氧化酶法测定大鼠的空腹血糖(FBG);放射免疫法测定空腹胰岛素(FINS),并计算胰岛素敏感指数(ISI);酶联免疫法测定大鼠的甘油三酯(TG)、总胆固醇(TCH)、游离脂肪酸(FFA)和糖化血红蛋白(GHb);果糖胺法测定糖化血清蛋白(GSP);Western blotting检测脂肪组织过氧化物酶体增殖物激活受体γ(PPARγ)的表达情况。结果: 与正常对照组相比,糖尿病模型组血脂、FBG以及GHb显著升高,FINS及ISI显著下降,脂肪细胞PPARγ蛋白表达水平降低。与模型组相比,TTPGL中、高剂量组大鼠的FBG和GSP显著降低,FINS以及ISI显著升高,脂肪组织PPARγ蛋白的表达水平升高(P<0.01或P<0.05);此外,TTPGL能显著降低糖尿病大鼠血脂水平,TG、TCH和FFA含量均明显降低(P<0.01或P<0.05)。结论: TTPGL能显著降低2型糖尿病大鼠的血糖和血脂水平,明显改善糖尿病动物的糖脂代谢紊乱,升高血清胰岛素水平,提高胰岛素敏感指数;其抗糖尿病作用机制可能与其增加PPARγ蛋白的表达有关。     

植物甾醇酯对大鼠主动脉衰老及相关基因表达的影响

目的:探讨植物甾醇酯延缓大鼠主动脉衰老的作用及其机制。方法:将42只12月龄雌性SD大鼠随机均分为对照组、模型组和植物甾醇酯干预组,分别喂食基础饲料、高脂饲料和高脂加2%植物甾醇酯(W/W)饲料6个月。采用HE染色法和Masson染色法对主动脉横截面石蜡切片进行染色,观察主动脉组织的病理学改变,对血管壁平滑肌细胞和胶原纤维的绝对面积进行图像分析。检测血浆脂质蛋白、晚期糖基化终末产物(AGEs)、丙二醛(MDA)的含量以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性。分别采用real-time PCR和Western blot的方法评估主动脉组织沉默信息调节因子1(SIRT1)和过氧化物酶体增殖物激活受体γ(PPARγ)的mRNA和蛋白表达水平。结果:与模型组相比,植物甾醇酯干预组的血浆总胆固醇和低密度脂蛋白胆固醇水平显著降低,高密度脂蛋白胆固醇的水平相反(P0.05),甘油三酯的水平没有统计学差异;主动脉内膜和中膜的增厚以及平滑肌细胞的迁移均得到改善;主动脉平滑肌细胞和胶原纤维的含量显著下降(P0.05);血浆AGEs的含量显著降低(P0.05);机体的抗氧化功能有所提升,血浆MDA的含量显著减少(P0.05),SOD和CAT活性的差异没有统计学意义;PPARγ的表达下调,SIRT1的表达上调(P0.05)。结论:植物甾醇酯能够延缓大鼠主动脉的衰老。其机制可能与降低机体活性氧的生成有关。植物甾醇酯可能通过激活SIRT1或抑制PPARγ的表达而发挥作用。     

姜黄素减轻氧化型低密度脂蛋白诱导的人主动脉内皮细胞损伤

目的:观察姜黄素对氧化型低密度脂蛋白(ox-LDL)诱导的人主动脉内皮细胞(HAECs)损伤的作用及分子机制。方法:以不同浓度姜黄素预处理体外培养的HAECs,再以ox-LDL对细胞进行干预。MTT法和Ed U法评估细胞增殖能力;ELISA法对培养液中白细胞介素-6(IL-6)、转化生长因子β1(TGFβ1)、高迁移率族蛋白1(HMGB1)以及分泌型晚期糖基化终产物受体(sRAGE)浓度进行检测;凝胶电泳迁移率实验(EMSA)评估过氧化物酶体增殖物激活受体γ(PPARγ)的结合活性;Western blot法检测HAECs中磷酸化PPARγ、血红素氧合酶-1(HO-1)、HMGB1、IL-6、TGFβ1和RAGE的表达水平。结果:ox-LDL处理的HAECs细胞活力和增殖能力下降,细胞内PPARγ/HO-1信号被抑制,其下游HMGB1/RAGE炎症通路被激活,细胞分泌的IL-6、TGFβ1、HMGB1以及sRAGE浓度显著增加。不同浓度姜黄素预处理可激活ox-LDL诱导的HAECs内PPARγ/HO-1信号通路,从而抑制下游HMGB1/RAGE炎症通路,降低IL-6、TGFβ1、HMGB1以及sRAGE炎症因子水平。结论:ox-LDL能够通过抑制PPARγ/HO-1而激活HMGB1/RAGE炎症通路造成HAECs损伤。姜黄素则能够通过活化PPARγ/HO-1通路抑制炎症反应,减轻ox-LDL对HAECs的损伤。     

硫化氢对糖尿病大鼠心肌纤维化及PPARγ、NF-κB表达的影响

目的:初步探讨硫化氢(H2S)对糖尿病心肌纤维化的影响及其作用机制。方法:采用链脲佐菌素(STZ)单次腹腔注射的方法制作大鼠糖尿病模型,以硫氢化钠作为外源性H2S供体。将40只雄性SD大鼠随机分为对照组、STZ组、STZ+H2S组及H2S组,每组各10只。8周后处死大鼠,HE染色及VG染色观察心肌胶原分布情况,并用图像分析系统测量心肌间质胶原容积分数。Western blotting观察大鼠心肌组织中Ⅰ型胶原、PPARγ和NF-κB的表达水平。结果:与对照组相比,STZ组大鼠心肌组织胶原纤维明显增多,Ⅰ型胶原表达水平明显升高(P0.05),PPARγ表达明显减少(P0.05),NF-κB蛋白表达水平明显升高(P0.05)。与STZ组相比,STZ+H2S组心肌胶原纤维较少,Ⅰ型胶原表达明显降低(P0.05),PPARγ表达显著上调(P0.05),NF-κB蛋白表达显著降低(P0.05),而H2S组大鼠心肌组织Ⅰ型胶原、PPARγ以及和NF-κB蛋白表达水平较对照组均无显著差异。结论:硫化氢可改善糖尿病心肌纤维化,其内在机制可能与PPARγ-NF-κB途径有关。     

FK506作为佐剂刺激Tfh细胞增强体液免疫水平的研究

目的:探讨他克莫司(FK506)作为佐剂通过刺激Tfh细胞增强疫苗体液免疫水平的机制。方法:利用FK506与模式蛋白(卵清白蛋白,OVA)皮下注射免疫BALB/c小鼠,免疫三次,利用ELISA方法检测抗体水平;利用抗体染色流式细胞仪检测Tfh细胞、B细胞表面分子IL-21R及记忆性B细胞标志分子CD27表达。结果:FK506作为OVA蛋白佐剂,能够显著提高小鼠OVA特异性的IgG水平,增强体液免疫水平;免疫后的小鼠Tfh细胞表达IL-21水平显著高于其他对照组。同时,B细胞表达IL-21R及记忆性B细胞标志分子CD27显著高于其他对照组。表明FK506作为佐剂刺激Tfh细胞表达IL-21,作用于B细胞增强抗体水平。结论:FK506能够作为蛋白疫苗佐剂刺激Tfh细胞表达IL-21;IL-21可能通过与B细胞表面IL-21R作用,增强抗体的分泌;并刺激记忆性B细胞的产生,进而增强体液免疫水平。     

FK506对BXSB狼疮性肾炎小鼠的治疗作用及其机制初步探讨

目的观察FK506对BXSB狼疮性肾炎小鼠治疗作用,初步探讨其作用机制。方法 6只12周龄雄性C57BL/6小鼠为正常对照组,12只12周龄雄性BXSB小鼠随机分为LN治疗组和LN未治疗组。治疗组予FK506 2 mg/kg隔日腹腔注射,未治疗组、正常对照组予NS 0.2 ml隔日腹腔注射,治疗至20周龄。PASM染色法观察肾组织病理变化,直接免疫荧光法观察肾组织IgG沉积,ELISA法检测血清抗-dsDNA抗体和IL-18水平,RT-PCR法检测肾组织IL-18 mRNA表达水平,免疫组化法检测肾组织IL-18表达水平。结果治疗组小鼠肾脏病理学改变明显好转,肾组织免疫球蛋白沉积减少,血清抗-dsDNA抗体和IL-18水平、肾组织IL-18mRNA和蛋白表达水平均低于未治疗组。结论 FK506对BXSB小鼠肾损害具有良好的治疗作用,抑制IL-18 mRNA的表达可能是FK506治疗LN的作用机制之一。     

FK506-binding protein of Neurospora crassa (NcFKBP) mediates sensitivity to the immunosuppressant FK506; resistant mutants identify two loci

Summary Growth of Neurospora crassa wild-type is inhibited by micromolar concentrations of the immuno-suppressive macrolide FK506. Spontaneous and induced mutations that confer resistance to FK506 identified two loci, fkr-1 and fkr-2. They map on the right arm of linkage group V on either side of inl with fkr-1 being centromere proximal. Allele fb (fkr-2) lacks immunodetectable N. crassa FK506-binding protein (NcFKBP). This demonstrates that the sensitivity of N. crassa towards FK506 is mediated by NcFKBP. FK506-binding proteins have been shown to be highly conserved, i.e., found in all eukaryotic cells tested, and to exhibit peptidyl-prolyl cis-trans isomerase (PPIase) activity in vitro. Possible functions for the loci are discussed. Apart from the resistance to FK506 no other mutant phenotype was detected not even in double mutants that lacked NcFKBP as well as cyclophilin. Cyclophilin mediates the cytotoxic effect of the immunosuppressive drug Cyclosporin A and is also characterized by PPIase activity in vitro. Both FK506-resistant alleles studied exhibit incomplete dominance in forced heterokaryons. A mechanism is proposed to explain this dominance especially in view of the NcFKBP-deficient allele, fb.     

The immunosuppressant FK506 ameliorates ischaemic damage in the rat brain

The effect of the immunosuppressant FK506 on ischaemic neuronal damage was studied in a rat model of transient cerebral ischemia induced by occlusion of both common carotid arteries in combination with hypotension for 10 min. Neuronal damage was assessed morphologically after 4 days of recovery. Treatment with FK506, given at a dose of 2 mg kg^-1 by intraperitoneal injections 30 min prior to ischemia and once daily during recovery, decreased neuronal damage by 52% in the hippocampal CA1 region and by 48% in the temporal cortex. The protection was not due to diminished body temperature or a marked reduction of ischaemia-induced synaptic overflow of glutamate. We propose that FK506 decreases neuronal damage either by inhibiting calcineurin-mediated events or by preserving mitochondrial function.     

普乐可复防治大鼠抗肾小球基底膜肾炎的实验研究

目的:观察普乐可复(FK506)防治大鼠抗肾小球基底膜(GBM)肾炎的疗效。方法:复制大鼠抗GBM肾炎模型。实验分3组:肾炎+FK506组、肾炎对照组及正常对照组。大鼠一次性尾静脉注射抗GBM抗血清后6 h内皮下注射FK506注射液(0.5 mg·kg^-1·d^-1), 至第21 d。对照组则给予等量的生理盐水。定期于第4 d、第14 d和第21 d, 检测大鼠尿蛋白、血清肌酐和尿素氮水平, 观察肾组织病理学改变, 以及检测T淋巴细胞转化功能。结果:肾炎对照组大鼠注射抗血清后于第4d即出现异常蛋白尿, 血清肌酐和尿素氮亦持续上升;肾小球内可见细胞数增加和新月体形成, 肾小管内大量蛋白管型, GBM呈不规则增厚, 足突大片融合;T淋巴细胞转化功能异常。而肾炎+FK506组大鼠上述病变均明显较轻。结论:FK506能够明显改善大鼠抗GBM肾炎的肾功能。     

Novel immunosuppressive effect of FK506 by augmentation of T cell apoptosis

We have recently reported the accumulation of oligoclonal activated T cells in the spontaneously developed autoimmune pancreatitis in aly/aly mouse. In this study, we examined the effects of FK506 in this mouse model in preventing autoimmune pancreatitis and investigated its action on calcium signalling apoptosis of alymphoplasia (aly) lymphocytes in vitro. Mice were treated with FK506 from 8 to 25 weeks of age. At the age of 15 weeks, minimal mononuclear cell infiltration was observed in the pancreas in both the FK506 treated group and the control group. Furthermore, a marked cell infiltration associated with destruction of acini and partial fatty changes were observed in 25-week-old control mice. In contrast, FK506 treated mice showed almost no tissue destruction or mononuclear cell infiltration at the age of 25 weeks. Furthermore, at 15 weeks of age, most mononuclear cells in FK506-treated mice were TUNEL positive, whereas only a few were positive in control mice. This augmentation of T cell apoptosis by FK506 was confirmed using naive splenocytes activated by PMA and ionomycin in vitro. Finally, a suppressive effect of FK506 on Bcl-2 production but not on Bax production was confirmed by Western blotting. This unique effect of FK506 on the augmentation of T cell apoptosis is probably one of the mechanisms explaining its beneficial effect on aly autoimmune pancreatitis.     

The effect of FK506 and cyclosporin A on antigen-induced arthritis.

FK506 and cyclosporin A inhibited the development of antigen-induced arthritis in the rat and rabbit. FK506 was five times more potent than cyclosporin A in the rat and approximately 20 times more potent in the rabbit. FK506 was effective in both species if administered either from the day of intra-articular administration of antigen or when the arthritis was established. In the rabbit, arthritis returned when administration of FK506 was stopped. FK506 (10 mg/kg/day) caused renal damage which was not observed at a dose of 2.5 mg/kg/day. Both of these doses were equally effective at inhibiting the arthritis. The conclusion from these studies is that FK506 is a more effective anti-arthritic agent than cyclosporin A and that a pronounced therapeutic effect can be achieved at non-toxic doses of the drug.     

Inhibition by FK506 of established lesions of collagen-induced arthritis in rats.

We investigated the superior potency of the immunosuppressive agent FK506 on collagen-induced arthritis in rats. In our initial studies, we demonstrated that only one shot administration of FK506 at a dose of 10 mg/kg on the same day as type II collagen immunization suppressed the incidence of arthritis completely as well as humoral and delayed-type hypersensitivity (DTH) skin test responses to type II collagen. Yet no major side effects were observed in the rats treated with such a high dose of FK506. Additional studies demonstrated that pretreatment with FK506 on day -7 or day -3 was effective in suppressing the severity of arthritis and immune responses to type II collagen. The immunosuppressive effect of a single high-dose administration of FK506 continued for at least 1 week in this animal model of arthritis. A single administration of FK506 at a dose of 10 mg/kg on day 12 or 15, after the clinical onset of arthritis, was also effective in suppressing the severity of arthritis and immune response to type II collagen. We conclude that FK506, in this model, possesses an important, curative action when applied therapeutically. The outlook of FK506 treatment in clinical autoimmunity is promising at present.     

Inhibitory effect of the immunosuppressant FK506 on apoptotic cell death induced by HIV-1 gp120

Human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 may play a central role in inducing immunoregulatory disorders after HIV infection. The apoptotic death of normal human peripheral blood mononuclear cells was induced by priming with gp120 followed by stimulation with an anti-T cell receptor (TCR) antibody. Tumor necrosis factor- produced by gp120-binding macrophages may be important to induce this cell death. Treatment of gp120-primed cells with an immunosuppressant (FK506) before TCR signaling inhibited apoptotic cell death, and this blocking effect of FK506 was concentration dependent. FK506 did not have any influence on cell growth and viability over the range of concentrations tested. These findings suggest that FK506 is a potentially useful drug in delaying the onset of AIDS after HIV infection.     

Neuroprotective effects of FK506 against excitotoxicity in organotypic hippocampal slice culture

FK506 has been originally classified as an immunosuppressant and is known to exhibit neurotrophic actions in vitro and protective effects on some neurological conditions. We investigated the neuroprotective effects of FK506 on kainic acid (KA)-induced neuronal death in organotypic hippocampal slice cultures (OHSCs). After an 18 h KA (5 μM) treatment, significantly neuronal death was detected in the CA3 region using propidium iodide staining. However, neuronal death was significantly prevented at 24 and 48 h after treatment with 0.1 μM FK506. Using cresyl violet staining, we also observed that an increased number of CA3 neurons survived in the 0.1 μM FK506 group compared to the KA only group. Based on the results of the Western blot analysis, the expressions of 5-lipoxygenase and caspase-3 were reduced 24 h after 0.1 μM FK506 treatment. The levels of superoxide dismutase (SOD) and phospho-Akt expression were increased by treatment with 0.1 μM FK506. These results suggest that FK506 may have a positive role in protecting neurons against cell death in the KA injury model of OHSCs.     

FK506-binding protein 5 inhibits proliferation and stimulates apoptosis of glioma cells

Introduction

FK506-binding protein 5 (FKBP5) is reported to act as a scaffolding protein for Akt to promote the dephosphorylation of AKT Ser473 and suppress pancreatic cancer growth. However, other studies have shown that FKBP5 promotes tumor growth and chemoresistance through regulating NF-κB signaling in other cancers. In this study, we attempted to investigate the role and mechanism of action of FKBP5 in the regulation of proliferation and apoptosis of glioma cells.

Material and methods

The glioma U251 cell line was used as the model. Cell proliferation was detected by MTT assay. Cell apoptosis was detected by annexin-V staining. Protein expression was detected by Western blot analysis.

Results

FKBP5 overexpression inhibited the proliferation of U251 cells significantly (p < 0.05), and promoted the apoptosis of U251 cells significantly (p < 0.05). In addition, FKBP5 overexpression inhibited the phosphorylation of Akt at Ser743, decreased the level of Bcl-2, increased the level of Bax, and enhanced the cleavage of caspase-9 and caspase-3 (p < 0.05 compared to control). In contrast, FKBP5 knockdown enhanced the proliferation of U251 cells, increased the phosphorylation of Akt significantly (p < 0.05), increased the expression of Bcl-2 and decreased the expression of Bax, and decreased the cleavage of caspase-9 and caspase-3 significantly (p < 0.05).

Conclusions

FKBP5 plays the role of a tumor suppressor in glioma by inhibiting the activation of Akt and stimulating the intrinsic mitochondrial apoptotic pathway, and could be used as a new target for gene therapy of glioma.