Indoleamine 2,3-dioxygenase (IDO) is essential for dendritic cell activation and chemotactic responsiveness to chemokines

Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy. In mice, IDO expression is an inducible feature of specific subsets of dendritic cells (DCs), and is important for T cell regulatory properties. However, the effect of IDO and tryptophan deprivation on DC func- tions remains unknown. We report here that when tryptophan utilization was prevented by a pharmacological inhibitor of IDO, 1-methyl tryptophan (1MT), DC activation induced by pathogenic stimulus lipopolysaccharide (LPS) or inflam- matory cytokine TNF-α was inhibited both phenotypically and functionally. Such an effect was less remarkable when DC was stimulated by a physiological stimulus, CD40 ligand. Tryptophan deprivation during DC activation also regu- lated the expression of CCR5 and CXCR4, as well as DC responsiveness to chemokines. These results suggest that tryptophan usage in the microenvironment is essential for DC maturation, and may also play a role in the regulation of DC migratory behaviors.

Indoleamine 2,3-dioxygenase: As a potential prognostic marker and immunotherapeutic target for hepatocellular carcinoma

Tumor cells induce an immunosuppressive microen-vironment which leads towards tumor immune escape. Understanding the intricacy of immunomodulation by tumor cells is essential for immunotherapy. Indoleamine 2,3-dioxygenase(IDO) is an immunosuppressive enzyme which mediates tumor immune escape in various cancers including hepatocellular carcinoma(HCC). IDO up-regulation in HCC may lead to recruitment of regulatory T-cells into tumor microenvironment and therefore inhibit local immune responses and promote metastasis. HCC associated fibroblasts stimulate natural killer cells dysfunction through prostaglandin E2 and subsequently IDO promotes favorable condition for tumor metastasis. IDO up-regulation induces immuno-suppression and may enhance the risk of hepatitis C virus and hepatitis B virus induced HCC. Therefore, IDO inhibitors as adjuvant therapeutic agents may have clinical implications in HCC. This review proposes future prospects of IDO not only as a therapeutic target but also as a prognostic marker for HCC.

Inhibition of allogeneic T-cell response by Kupffer cells expressing indoleamine 2,3-dioxygenase

AIM:To explore the possibility and mechanism of inhibiting allogeneic T-cell responses by Kupffer cells (KC)pretreated with interferon-γ(IFN-γ)in vitro. METHODS:The expressions of indoleamine 2,3-dioxygenase(IDO)mRNA and FasL mRNA in KC pretreated with IFN-γwere studied with real-time polymerase chain reaction(PCR).The catabolism of tryptophan by IDO from KC was analyzed by high performance liquid chromatography.Allogeneic T-cell response was used to confirm the inhibition of KC in vitro.The proliferation of lymphocytes was detected using[ 3 H]thymidine incorporation.Cell cycle and lymphocyte apoptosis were evaluated by flow cytometric assay. RESULTS:Real-time PCR revealed IDO mRNA and FasL mRNA expressions in KC pretreated with IFN-γ,and IDO catabolic effect was confirmed by a decrease in tryptophan and increase in kynurenine concentration. KC expressing IDO and FasL in BABL/c mice acquired the ability to suppress the proliferation of T-cells from C57BL/6,which could be blocked by addition of 1-methyl-tryptophan and anti-FasL antibody.KC expressing IDO could induce allogeneic T-cell apoptosisCONCLUSION:In addition to Fas/FasL pathway,IDO may be another mechanism for KC to induce immune tolerance.

Expression of indoleamine 2,3-dioxygenase in a murine model of Aspergillus fumigatus keratitis

AIM： To observe the presence and expression of indoleamine 2,3-dioxygenase（IDO） during the corneal immunity to Aspergillus fumigatus（A. fumigatus） in the murine models.·METHODS： The murine model of fungal keratitis was established by smearing with colonies of A. fumigatus after scraping central epithelium of cornea and covering with contact lenses in C57BL/6 mice. The mice were randomly divided into control group, sham group and A.fumigatus keratitis group. The cornea was monitored daily using a slit lamp and recorded disease score after infection. Corneal lesion was detected by immunofluorescence staining. IDO m RNA and protein were also detected by quantitative reverse transcription-polymerase chain reaction（q RT-PCR） and Western blot.· RESULTS： The disease score and slit lamp photography indicated that disease severity was consistent with corneal inflammation in the murine models, and the disease scores in A. fumigatus keratitis group were obviously higher than those in the sham group. By immunofluorescence staining, IDO was mainly localized in corneal epithelium and stroma in the murine corneal tissues with A. fumigatus keratitis. Compared with the sham group, IDO m RNA expression was significantly enhanced in corneal epithelium infected by A. fumigatus. Furthermore, IDO protein expression detected by Western blot was in accord with transcript levels of IDO m RNA measured by q RT-PCR. IDO protein expression was enhanced after A. fumigatus infection compared with the sham group.·CONCLUSION： IDO is detected in corneal epithelium and stroma locally, which indicates IDO takes part in the pathogenesis of A. fumigatus keratitis and plays a key role in immune regulation at the early stage.

Indoleamine 2,3-dioxygenase adjusts neutrophils recruitment and chemotaxis in Aspergillus fumigatus keratitis

AIM: To explore the effect of indoleamine 2,3-dioxygenase(IDO) on recruitment and chemotaxis function of neutrophils in Aspergillus fumigatus(A.fumigatus) keratitis.METHODS: C57BL/6 mice models of A.fumigatus keratitis were established by inoculating hyphae of A.fumigatus evenly on the corneas.The clinical scores and inflammatory cytokines expression were measured respectively on the 1^(st), 3^(th), 5^(th) day after infection.The 1-MT(1 mg/m L) was administered by gavage to exert an inhibitory effect on IDO during infection.The mice were divided into control group, 1-MT group, A.fumigatus(A.F.) group, and 1-MT+A.F.groups.The corneas were monitored by slit lamp microscopy, and recorded disease scores in 3 d after infection.Myeloperoxidase(MPO) assay was done to evaluate the neutrophils infiltration.Immunofluorescence staining was used to detect the recruitment of neutrophils in murine corneas.The m RNA of inflammatory cytokines was measured with reverse transcription-polymerase chain reaction(RT-PCR).RESULTS: The corneal inflammation and the clinical score reached the peak on the 3;day after the corneal infection.The m RNA of inflammatory cytokines of the A.F.group reached the highest on the 3;day after the infection accordingly.Meanwhile, the results of slit light photography indicated that inhibitors of IDO made inflammation more serious contrasted with the A.F.group on the 3;day.Besides, imunofluorescence staining and MPO indicated that 1-MT enhanced the recruitment, infiltration and chemotaxis of neutrophils obviously in contrast to the A.F.group.RT-PCR indicated that 1-MT increased the expression of CXCL-1, ICAM-1, IL-1β, and IL-8 significantly.CONCLUSION: IDO participates in the pathogenesis of A.fumigatus keratitis and plays an important role in inducing immune protection by inhibiting neutrophils-related inflammatory reaction and suppressing recruitment and chemotaxis of the neutrophils.

Subcloning and high level expression of xylE gene coding for the catechol 2, 3 dioxygenase in E. coli

To construct a high-level expression of xylE gene in E. coli for quick detection of environmental pollution of aromatic compounds. Methods and Results: XylE gene coding for the catechol 2, 3 dioxygenase (CatO2ase ) was amplified from the recombinant plasmid pTG402 by using PCR technique and was subcloned into pUC118N and pUC119N. The single stranded recombinant phage DNA from the transformed E. coli MV1184 cells was used for sequencing. The sequence of xylE gene was proved to be the same as reported. The gene was then subcloned into the high expression plasmid pJLA503, its expression amount being about 34. 2% of the total bacterial proteins. Conclusion: xylE gene is highly expressed in host E. coli TG1.

T-cell proliferation is inhibited by the induction of indoleamine 2,3-dioxygenase in spleen-derived dendritic cells in rat

Background Increasing evidence suggests that, by the production of indoleamine 2, 3-dioxygenase （IDO）, dendritic cells （DC） may reduce the activity of T lymphocytes and inhibit T lymphocyte proliferation-induced immune tolerance.One promising way is inspired by increasing IDO expression in DG cells for immune tolerance after transplantation. The aim of this work was to examine the effect of interferon-y （IFN-γ） on the expression of IDO by DC.Methods Spleen-derived rat DCs were cultured and induced by cytokines, and the expression of OX62 and surface molecules CD80 and CD86 were measured with flow cytometry. After the DCs were induced by IFN-γ at different concentrations （0, 100, 300, 500 U/ml）, the expression levels of IDO mRNA were measured with real-time PCR, and the expression levels of IDO protein in DCs were measured with Western blotting. The allogeneic mixed lymphocyte reaction （MLR） was used to test the effects of DCs incubated with different concentrations of IFN-γ on allogeneic T lymphocyte proliferation.Results Under the microscope, the DCs induced by IFN-γ showed a typical dendritic morphology. The expression rate of OX62 was above 80% and the positive expression rates of CD80 and CD86 were both about 80%. The expressions of IDO mRNA and IDO protein increased gradually with the increase of IFN-γ concentration, showing statistical significance in the differences between the groups （P 〈0.05）. Compared with the control DC, the DC incubated with IFN-γ had a notable decrease in allostimulatory activity （P 〈0.05）. With the increasing IFN-γ concentration, the T lymphocyte proliferation decreased, and the difference between the groups was also statistically significant （P 〈0.05）.Conclusions The highly purified spleen derived rat DCs can be successfully acquired through the improved adhesion in-vitro method. IFN-γ can induce increased expression of IDO in spleen-derived rat DCs and reduce the spleen DCs＇ capacity to stimulate the proliferation of allogeneic T cells.

Up-regulation of indoleamine 2,3-dioxygenase 1(IDO1)expression and catalytic activity is associated with immunosuppression and poor prognosis in penile squamous cell carcinoma patients

Background: Indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan (Trp)catabolism have been demonstrated to play an important role in tumor immunosuppression. This study examined the expression and catalytic activity of IDO1 in penilesquamous cell carcinoma (PSCC) and explored their clinical significance.Methods: IDO1 expression level, serum concentrations of Trp and kynurenine (Kyn)were examined in 114 PSCC patients by immunohistonchemistry and solid-phaseextraction-liquid chromatography-tandem mass spectrometry. The survival was analyzed using Kaplan-Meier method and the log-rank test. Hazard ratio of death was analyzed via univariate and multivariate Cox regression. Immune cell types were definedby principal component analysis. The correlativity was assessed by Pearson’s correlation analysis.Results: The expression level of IDO1 in PSCC cells was positively correlatedwith serum Kyn concentration and Kyn/Trp radio (KTR;both P < 0.001) but negatively correlated with serum Trp concentration (P = 0.001). Additionally, IDO1 upregulation in cancer cells and the increase of serum KTR were significantly associated with advanced N stage (both P < 0.001) and high pathologic grade (P = 0.008and 0.032, respectively). High expression level of IDO1 in cancer cells and serumKTR were associated with short disease-specific survival (both P < 0.001). However, besides N stage (hazard radio [HR], 6.926;95% confidence interval [CI],2.458-19.068;P < 0.001) and pathologic grade (HR, 2.194;95% CI, 1.021-4.529;P = 0.038), only serum KTR (HR, 2.780;95% CI, 1.066-7.215;P = 0.036) was anindependent predictor for PSCC prognosis. IDO1 expression was positively correlated with the expression of interferon-𝛾 (IFN𝛾, P < 0.001) and immunosuppressivemarkers (programmed cell death protein 1, cytotoxic T-lymphocyte-associated protein 4 and programmed death-ligand 1 and 2;all P < 0.05), and the infiltration ofimmune cells (including cytotoxic T lymphocytes, regulatory T lymphocytes, tumorassociated macrophages, and myeloid-derived suppressor cells;all P < 0.001) inPSCC tissues. Furthermore, the expression of IDO1 was induced by IFN𝛾 in a dosedependent manner in PSCC cells.Conclusions: IFN𝛾-induced IDO1 plays a crucial role in immunoediting andimmunosuppression in PSCC. Additionally, serum KTR, an indicator of IDO1catabolic activity, can be utilized as an independent prognostic factor for PSCC.

PLOD1、NFE2L3、KLKB1蛋白在结直肠癌组织中的表达水平及与其临床病理特征的相关性

目的 探讨前胶原赖氨酸2-氧代戊二酸5-双加氧酶1(PLOD1)、核因子E2相关因子3(NFE2L3)、血浆激肽释放酶B1(KLKB1)蛋白在结直肠癌组织中的表达水平及与其临床病理特征的相关性。方法 回顾性选取2020年1月至2023年12月安康市中心医院收治的120例结直肠癌患者作为研究对象。分别取患者的结直肠癌组织及癌旁组织进行免疫组织化学检测,检测PLOD1、NFE2L3、KLKB1蛋白表达水平。并对比不同TNF分期、组织分化程度、淋巴结转移患者PLOD1、NFE2L3、KLKB1蛋白表达水平,并采用Spearman相关性分析法分析PLOD1、NFE2L3、KLKB1蛋白表达水平与临床病理特征的相关性。结果 结直肠癌组织PLOD1、NFE2L3蛋白阳性率分别为70.00%、60.00%,均高于癌旁组织(22.50%、17.50%),结直肠癌组织KLKB1蛋白阳性率为43.33%,低于癌旁组织(71.67%),差异均有统计学意义(P<0.05)。TNF分期Ⅳ期患者PLOD1与NFE2L3蛋白阳性率分别为100.00%与95.24%,均明显高于Ⅲ期(83.33%与73.33%)、Ⅱ期(59.09%与45.45%)、Ⅰ期(48.00%与32.00%),Ⅳ期患者KLKB1蛋白阳性率为14.29%,明显低于Ⅲ期(36.67%)、Ⅱ期(34.09%)、Ⅰ期(92.00%),差异均有统计学意义(P<0.05)。低分化患者PLOD1与NFE2L3蛋白阳性率分别为100.00%与90.00%,明显高于中分化(81.13%与50.94%)、高分化(44.68%与23.40%),低分化患者KLKB1蛋白阳性率为20.00%,明显低于中分化(30.19%)、高分化(68.09%),差异均有统计学意义(P<0.05)。Spearman相关分析显示:PLOD1、NFE2L3与TNF分期、淋巴结转移、肿瘤分化程度具有相关性,KLKB1与TNF分期、淋巴结转移、肿瘤分化程度具有相关性(P<0.05)。结论 结直肠癌患者肿瘤组织中PLOD1、NFE2L3蛋白呈现低表达状态,KLKB1蛋白呈现高表达状态,且PLOD1、NFE2L3、KLKB1蛋白表达水平与结直肠癌的TNF分期、组织分化程度及淋巴结转移情况密切相关。

Indoleamine-2,3-dioxygenase 1/cyclooxygenase 2 expression prediction for adverse prognosis in colorectal cancer

AIM To evaluate indoleamine-2,3-dioxygenase 1/cyclooxygenase 2(IDO1/COX2) expression as an independent prognostic biomarker for colorectal cancer(CRC) patients.METHODS We retrospectively studied the medical records of 95 patients who received surgical resection from August 2008 to January 2010. All patients were randomly assigned to adjuvant treatment with or without celecoxib groups after surgery. We performed standard immunohistochemistry to assess the expression levels of IDO1/COX2 and evaluated the correlation of IDO1/COX2 with clinicopathological factors and overall survival(OS) outcomes.RESULTS The expression of nuclear IDO1 was significantly correlated with body mass index(P < 0.001), and IDO1 expression displayed no association with sex, age, tumor differentiation, T stage, N stage, carcinoembryonic antigen, cancer antigen 19-9, CD3+ and CD8+ tumor infiltrating lymphocytes, and COX2. In univariate analysis, we found that nuclear IDO1(P = 0.039), nuclear/cytoplasmic IDO1 [hazard ratio(HR) = 2.044, 95% confidence interval(CI): 0.871-4.798, P = 0.039], nuclear IDO1/COX2(HR = 3.048, 95%CI: 0.868-10.7, P = 0.0049) and cytoplasmic IDO1/COX2(HR = 2.109, 95%CI: 0.976-4.558, P = 0.022) all yielded significantly poor OS outcomes. Nuclear IDO1(P = 0.041), nuclear/cytoplasmic IDO1(HR = 3.023, 95%CI: 0.585-15.61, P = 0.041) and cytoplasmic IDO1/COX2(HR = 2.740, 95%CI: 0.764-9.831, P = 0.038) have significantly poor OS outcomes for the CRC celecoxib subgroup. In our multivariate Cox model, high coexpression of cytoplasmic IDO1/COX2 was found to be an independent predictor of poor outcome in CRC(HR = 2.218, 95%CI: 1.011-4.48, P = 0.047) and celecoxib subgroup patients(HR = 3.210, 95%CI: 1.074-9.590, P = 0.037).CONCLUSION Our results showed that cytoplasmic IDO1/COX2 coexpression could be used as an independent poor predictor for OS in CRC.

吲哚胺2,3-双加氧酶参与乳腺癌患者免疫耐受的研究

目的:研究吲哚胺2,3-双加氧酶(Indoleamine2,3-dioxygenase,IDO)在乳腺癌组织和引流淋巴结中的表达及调节性T细胞在相应组织内的分布,探讨IDO在乳腺癌免疫耐受中的作用机制。方法:收集26例乳腺癌患者的癌组织、癌旁正常乳腺、引流淋巴结和10例乳腺良性病变组织,用RT-PCR法检测IDO mRNA表达,用免疫组织化学法检测IDO和Foxp3蛋白表达。结果:乳腺癌引流淋巴结中IDO mRNA表达水平及IDO表达阳性指数[(19.59±7.65)%]高于原发乳腺癌组织[IDO表达阳性指数(13.16±7.82)%](P<0.05),乳腺癌组织中IDO mRNA表达水平及IDO表达阳性指数高于乳腺良性病变组织[IDO表达阳性指数(3.24±1.30)%]和癌旁正常乳腺组织[IDO阳性细胞指数(2.70±1.53)%](P均<0.05)。乳腺癌组织中IDO表达水平与肿瘤临床分期和淋巴结转移相关(P<0.05)。乳腺癌引流淋巴结中Foxp3阳性细胞指数[(6.13±2.31)%]高于乳腺原发癌[(3.50±1.04)%],乳腺癌组织中Foxp3阳性细胞指数高于乳腺良性病变[(0.71±0.42)%]和癌旁正常乳腺组织[(0.55±0.34)%](P均<0.05)。乳腺癌和引流淋巴结中IDO的表达水平与Treg细胞的分布间均正性相关(r2=0.449,r2=0.454,P均<0.05)。结论:IDO在乳腺癌细胞中表达增高,并伴随乳腺癌和引流淋巴结中Treg细胞比例升高,提示IDO表达增高有可能通过募集Treg细胞参与肿瘤和引流淋巴结内的免疫耐受。

细粒棘球蚴重组抗原B诱导小鼠骨髓源树突状细胞表达吲哚胺2,3-双加氧酶的研究

目的观察细粒棘球蚴重组抗原B(rAgB)体外诱导小鼠骨髓源树突状细胞表达吲哚胺2,3-双加氧酶(IDO)的情况。方法从小鼠股骨中分离出骨髓细胞,进行小鼠重组巨噬细胞集落刺激因子(rmGM-CSF)的诱导,培养并获得CD11c+树突状细胞。应用倒置显微镜和扫描电镜观察树突状细胞形态,采用流式细胞术检测其表面标志物;用混合淋巴细胞反应(MLR)观察树突状细胞对T淋巴细胞的增殖能力。培养至第6天,收集未成熟树突状细胞进行流式细胞术检测;另向部分未成熟树突状细胞中加脂多糖(LPS)刺激24 h后,收集成熟树突状细胞,进行流式细胞术检测。在获得的未成熟树突状细胞中分别加入RPMI 1640完全培养液(为阴性对照组)、重组小鼠γ干扰素(rmIFN-γ,1 000 U/ml,为IFN-γ组)和rAgB(终浓度15μg/ml,为rAgB组),培养24 h后,通过细胞免疫组织化学和蛋白质印迹(Western blot-ting)检测各组树突状细胞IDO的表达情况。结果获得纯度为80%的CD11c+树突状细胞,在倒置显微镜和扫描电镜下均观察到典型树突状细胞。经LPS刺激的成熟树突状细胞的CD40、CD80和主要组织相容性复合体(MHC)Ⅱ类分子I-A/I-E的阳性表达率与未成熟树突状细胞的相比,差异均有统计学意义(均P<0.05)。MLR结果显示,诱导形成的树突状细胞具有刺激T淋巴细胞增殖的能力。细胞免疫组织化学方法检测结果显示,阴性对照组、阳性对照组和rAgB组的IDO阳性表达率分别为(4.544±1.752)%、(20.464±4.452)%和(11.148±1.966)%,3组间的差异均有统计学意义(均P<0.05)。Western blotting结果表明,3组IDO蛋白与相应甘油醛-3-磷酸脱氢酶(GAPDH)蛋白的灰度值之比分别为(0.229±0.085)、(0.794±0.114)和(0.573±0.129),其中rAgB组与阴性对照组相比差异有统计学意义(P<0.05),与IFN-γ组相比差异无统计学意义(P>0.05)。结论细粒棘球蚴重组抗原B在体外具有诱导树突状细胞表达吲哚胺2,3-双加氧酶的功能。

姜黄素抑制IFN-γ诱导的肿瘤细胞内吲哚胺2,3-双加氧酶的表达

目的:研究姜黄素对IFN-γ诱导的肿瘤细胞内吲哚胺2,3-双加氧酶(IDO)表达的影响。方法:利用低浓度的姜黄素作用于人乳腺癌细胞A431、人宫颈癌细胞HeLa、人肝癌细胞HepG2、人鼻咽癌细胞CNE2各24h,通过四甲基偶氮唑盐(MTT)比色检测细胞的增殖;利用免疫印记检测姜黄素对这些肿瘤细胞内IDO表达的影响;利用逆转录聚合酶链反应(RT-PCR)检测姜黄素对IDO基因表达的关键性干扰素应答因子1(IRF-1)的影响。结果:在这些肿瘤细胞内姜黄素对IDO的表达均有抑制作用,但姜黄素并没有抑制肿瘤细胞内IRF-1的转录。结论:姜黄素能抑制肿瘤细胞内IDO的表达。

吲哚胺2,3-二氧化酶与免疫系统功能调节

免疫应答受多种因素影响和调节,从而维持机体内环境的稳定。巨噬细胞、树突状细胞等抗原提呈细胞表达的吲哚胺2,3-二氧化酶(Indoleam ine 2,3-d ioxygenase,IDO)清除局部微环境中的色氨酸,诱导T淋巴细胞的凋亡,通过调节性T细胞的作用抑制T细胞的克隆性增生,参于细胞免疫的调节;在机体维持正常的妊娠以及自身免疫性疾病、器官移植排斥反应、肿瘤等疾病的发生发展中起着重要作用。调控IDO的活性可能是寻找防治免疫相关性疾病药物的新途径。

吲哚胺2,3-二氧化酶在人急性单核细胞白血病(M_5)和急性淋巴细胞白血病细胞中的表达及其抑制剂1-甲基色氨酸的治疗作用(英文)

本研究旨在探讨吲哚胺2,3-二氧化酶(IDO)在白血病细胞中的表达和作用。应用间接免疫荧光染色光法检测人急性单核细胞白血病(M5)和急性淋巴细胞白血病(ALL)的细胞内吲哚胺2,3-二氧化酶的表达情况,并以小鼠急性淋巴细胞白血病细胞系L1210建立白血病小鼠模型以观察吲哚胺2,3-二氧化酶抑制剂1-甲基色氨酸是否具有抑制白血病细胞生长的作用。结果表明:M5和ALL的白血病细胞中吲哚胺2,3-二氧化酶阳性细胞率分别为29.4±11.2%和24.7±7.96%,而对照组的外周血单个核细胞中吲哚胺2,3-二氧化酶阳性细胞率仅为3±1.2%;两个白血病组与正常对照组在吲哚胺2,3-二氧化酶阳性细胞率方面的差异均有显著的统计学意义(P<0.05),而M5与ALL组之间在吲哚胺2,3-二氧化酶阳性细胞率方面无显著性差异(P>0.05);1-甲基色氨酸(1-MT)治疗的白血病小鼠与对照组比较,肿瘤消退,生存期延长(P<0.05),部分治疗小鼠达到无病长期生存(注射肿瘤细胞后生存期超过3个月)。结论:人急性单核细胞白血病(M5)和急性淋巴细胞白血病(ALL)的细胞均表达吲哚胺2,3-二氧化酶,1-甲基色氨酸对白血病小鼠有一定的治疗作用。

吲哚胺2,3双加氧酶在肿瘤局部免疫耐受中的作用

吲哚胺2,3双加氧酶(IDO)是人体内肝外色氨酸代谢限速酶,最近研究表明,在肿瘤微环境内产生免疫耐受的机制中,多种细胞成分通过高表达IDO,导致肿瘤局部色氨酸代谢异常及调节性T细胞形成,对T细胞的增殖、分化和活性产生影响,进而介导肿瘤局部的T细胞免疫耐受,在恶性肿瘤的发生、发展和转移过程中发挥了重要作用。现就吲哚胺2,3双加氧酶在肿瘤局部免疫耐受中的作用作一综述。

沉默吲哚胺2,3-双加氧酶2基因对黑色素瘤细胞B16-BL6增殖、迁移和侵袭的影响

目的:探讨沉默吲哚胺2,3-双加氧酶2(IDO2)基因对小鼠黑色素瘤B16-BL6细胞增殖、迁移及侵袭等生物学行为的影响。方法:IDO2-siRNA转染体外培养的黑色素瘤细胞B16-BL6,应用real-time PCR和Western blot检测IDO2和IDO1基因的表达;平板集落形成实验检测IDO2基因沉默对肿瘤细胞增殖的影响;细胞划痕实验和Transwell小室细胞迁移实验观察IDO2对肿瘤细胞迁移的影响;Transwell小室侵袭实验观察肿瘤细胞侵袭能力。结果:沉默B16-BL6细胞中IDO2基因能使细胞单集落形成密度降低,划痕迁移变慢,Transwell小室细胞迁移数减少,侵袭细胞数减少。结论:沉默IDO2可以影响黑色素瘤细胞B16-BL6的增殖、迁移和侵袭能力。

吲哚胺2,3-双加氧酶及细胞因子在创伤后应激障碍患者中的表达变化及意义

目的探讨干扰素-γ(interferon-γ,INF-γ)、肿瘤坏死因子-α(tumor necrosis factor,TNF-α)、白介素-6(interleukin-6,IL-6)与吲哚胺2,3-双加氧酶(indoleamine 2,3-dioxy-genase,IDO)在创伤后应激障碍(PTSD)患者血清中表达变化及其临床意义。方法采集80例PTSD患者血清,同时收集80例健康对照组血清,运用酶联免疫吸附法(ELISA)和Western blot的方法对PTSD患者血清中INF-γ、TNF-α、IL-6及IDO进行检测,与对照组进行比较。结果实验表明PTSD组及正常对照组血清INF-γ、TNF-α、IL-6、IDO水平分别为[(28.43±11.23)vs.(3.01±1.12)pg/mL]、[(14.58±2.16)vs.(2.45±0.90)pg/mL]、[(16.34±5.31)vs.(2.01±1.08)pg/mL]、[(0.223 5±0.061 1)vs.(0.031 2±0.001 6)],PTSD组明显高于正常对照组(均P<0.01)。结论 INF-γ、TNF-α、IL-6及IDO表达的异常升高可能在PTSD的发病机制中扮演重要角色。

GITRL对Kupffer细胞内脂多糖诱导的吲哚胺2,3双加氧酶的作用研究

目的:研究糖皮质激素诱导的TNF受体配体(GITRL)对Kupffer细胞(KCs)内脂多糖(LPS)诱导的吲哚胺2,3双加氧酶(IDO)的影响。方法:分离小鼠KCs后分为5组:Control组,只加培养基;LPS组,加入LPS(10μg/ml);LPS+Control siRNA组,转染Control siRNA后同LPS组;LPS+GITRLsiRNA组,转染GITRLsiRNA后同LPS组;LPS+Dex组,地塞米松(100μmol/L)处理后同LPS组。处理24小时后,分别采用免疫细胞化学染色、蛋白免疫印记和ELISA法检测KCs的GITRL、IDO表达及肿瘤坏死因子(TNF)-α分泌。结果:和Control组比较,LPS刺激后KCs上GITRL的表达明显上调(P<0.05),而沉默GITRL基因或者使用地塞米松能减弱其升高(P<0.05)。LPS可以诱导IDO和TNF-α在KCs上的高表达,然而GITRL基因沉默可以抑制其诱导的IDO和TNF-α的表达(P<0.05),同样地塞米松预处理也能够减弱其诱导的IDO和TNF-α的表达(P<0.05)。结论:GITRL介导了KCs内LPS诱导的IDO,地塞米松可通过下调GITRL的表达以降低LPS诱导的IDO。

Vav1在吲哚胺2,3双加氧酶抑制T细胞中的作用初探

目的:探讨吲哚胺2,3双加氧酶(IDO)抑制T细胞中信号传导分子Vav1的分子机制。方法:应用稳定表达IDO的CHO细胞株,与纯化的外周血T细胞共孵育,检测IDO抑制T细胞增殖,诱导凋亡的情况,通过semi-quantitative RT-PCR检测T细胞中Vav1、IL-2 mRNA表达变化;Western blot及免疫沉淀技术检测Vav1蛋白表达及活化情况。结果:IDO可抑制T细胞的增殖。T细胞中Vav1和IL-2 mRNA水平明显下降(P<0.05)。而且,IDO还能使Vav1蛋白的表达和磷酸化水平降低。结论:研究证实在肿瘤局部产生于抗原呈递细胞或肿瘤细胞的IDO,可能通过抑制细胞内重要的信号传导蛋白Vav1的表达和磷酸化过程,使肿瘤浸润淋巴细胞的主动免疫受损,有利于肿瘤发生免疫逃逸。