Dendritic cell immunotherapy for autoimmune diabetes

Dendritic cells (DC) play important roles in the initiation of immune responses and maintenance of self-tolerance. We have been studying the role of DC in the pathogenesis of type 1 diabetes and exploring the ability of specific DC subsets to prevent diabetes in non-obse diabetic (NOD) mice. DC subeets that prevent diabetes in this model have a mature phenotype and induce the production of regulatory Th2 cells. We review here recent advances in this area and highlight the importance of optimizing culture conditions and purification methods in the isolation of therapeutic DC.     

Inhibition of histone deacetylase down-regulates the expression of hypoxia-induced vascular endothelial growth factor by rheumatoid synovial fibroblasts

Objective: To investigate the effect of FK228 on the in vitro expression of hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) by rheumatoid arthritis synovial fibroblasts (RASFs), and on the in vivo expression of VEGF and angiogenesis in the synovial tissue of mice with collagen-antibody-induced arthritis (CAIA). Methods: RASFs were stimulated with IL-1β and TNFα and then incubated under hypoxia (1 % O₂) with various concentrations of FK228. The effects of FK228 on the expression of HIF-1α and VEGF mRNA were examined by quantitative real-time PCR. Changes in HIF-1α protein expression and the secretion of VEGF protein into the culture medium were examined by Western blot analysis and ELISA, respectively. Immunohistochemical analysis was carried out to investigate the expression and distribution of VEGF in synovial tissues of CAIA mice. Results: The cytokine-stimulated expression of HIF-1α and VEGF mRNA was inhibited by FK228 in a dose-dependent manner. FK228 also reduced the expression of HIF-1α and VEGF protein. Intravenous administration of FK228 (2.5 mg/kg) suppressed VEGF expression, and also blocked angiogenesis in the synovial tissue of CAIA. Conclusion: FK228 may exhibit a therapeutic effect on RA by inhibition of angiogenesis through down-regulation of angiogenesis related factors, HIF-1α and VEGF. Received 28 February 2007; returned for revision 19 March 2007; accepted by J. Di Battista 11 July 2007     

组蛋白去乙酰化酶抑制剂与细胞周期和凋亡关系的研究进展

表观遗传学是目前遗传学研究的热点。组蛋白乙酰化修饰是一种重要的表观遗传学调控方式,参与调控染色质构象变化和转录表达过程,组蛋白乙酰化状态紊乱与肿瘤的发生发展关系密切。研究发现,组蛋白去乙酰化酶抑制剂(histone deacetylase in-hibitor,HDACi)可以纠正肿瘤细胞异常的乙酰化状态,诱导肿瘤细胞发生细胞周期停滞和凋亡,逆转肿瘤细胞恶性表型。1组蛋白乙酰化酶(histone acetyltransferase,HAT)和组蛋白去乙酰化酶(histone deacetylase,HDAC)真核生物染色体的基本单位是核小体,核小体的核心是由4种组蛋白(H2A、H2B、H3和H4)各2…     

Dendritic cell homeostasis is maintained by nonhematopoietic and T‐cell‐produced Flt3‐ligand in steady state and during immune responses

Lymphoid‐tissue dendritic cells (DCs) are short‐lived and need to be continuously replenished from bone marrow‐derived DC progenitor cells. Fms‐related tyrosine kinase 3 is expressed during cellular development from hematopoietic progenitors to lymphoid‐tissue DCs. Fms‐related tyrosine kinase 3 ligand (Flt3L) is an essential, nonredundant cytokine for DC progenitor to lymphoid tissue DC differentiation and maintenance. However, which cells contribute to Flt3L production and how Flt3L cytokine levels are regulated in steady state and during immune reactions remains to be determined. Here we demonstrate that besides nonhematopoietic cells, WT T cells produce Flt3L and contribute to the generation of both classical DCs (cDCs) and plasmacytoid DCs in Flt3L^?/? mice. Upon stimulation in vitro, CD4⁺ T cells produce more Flt3L than CD8⁺ T cells. Moreover, in vivo stimulation of naïve OT‐II CD4⁺ T cells with OVA leads to increase of pre‐cDCs and cDCs in draining lymph nodes of Flt3L^?/? mice in a partially Flt3L‐dependent manner. Thus, Flt3L‐mediated lymphoid tissue DC homeostasis is regulated by steady‐state T cells as well as by proliferative T cells, fostering local development of lymphoid organ resident DCs.     

组蛋白去乙酰化酶1在子宫内膜异位症中的表达及意义

目的 研究组蛋白去乙酰化酶1(HDAC1)在子宫内膜异位症患者在位及异位内膜中的表达,探讨其在子宫内膜异位症发生、发展中的作用. 方法 应用免疫组织化学和免疫印迹法检测20例子宫内膜异位症患者在位内膜和异位内膜组织(研究组)中及20例子宫肌瘤患者的子宫内膜组织(对照组)HDAC1的表达情况. 结果 HDAC1阳性着色主要分布于子宫内膜上皮细胞和间质细胞的细胞核,在位内膜中HDAC1的表达强度明显高于对照组子宫内膜(P<0.01).免疫印迹检测提示,子宫内膜异位症在位内膜和异位内膜组织中HDAC1蛋白的相对表达量分别为2.67±0.69和2.55±1.36,显著高于对照组子宫内膜1.63±0.93(P<0.01,P<0.05);而在位内膜组与异位内膜组之间无统计学差异(P＞0.05). 结论 HDAC1在子宫内膜异位症在位和异位内膜组织中的高表达,可能在子宫内膜异位症的发生、发展中起重要作用.     

组蛋白去乙酰化酶抑制剂罗米地辛对小鼠T细胞表型及功能的影响

目的:通过体外实验观察罗米地辛对效应T细胞和调节性T细胞的作用。方法:取CFSE标记的淋巴细胞、CD4+T细胞和CD8+T细胞作为反应细胞,实验组加入不同浓度梯度(1、3、5μmol/L)的罗米地辛及CD3/CD28单抗进行淋巴细胞培养,以仅加入CD3/CD28单抗作为阳性对照组,另设空白对照组。培养72 h后检测各组细胞的增殖情况。以淋巴细胞作为反应细胞,实验组、阳性对照组及空白对照组设定同上,72 h后检测各组中CD4+Foxp3+T细胞与CD4+T细胞的比例变化。同时采用ELISA检测培养液中相关细胞因子,如TNF-α、IL-10及TGF-β水平的变化。结果:罗米地辛剂量依赖性地抑制CD3/CD28单抗诱导的淋巴细胞、CD4+T细胞和CD8+T细胞的增殖(P0.05)。在CD3/CD28单抗存在的条件下,1μmol/L的罗米地辛不能诱导CD4+Foxp3+T细胞的比例上调(P0.05)。但提高罗米地辛的浓度至3μmol/L和5μmol/L后,CD4+Foxp3+T细胞的比例显著提高(P0.05)。随着罗米地辛浓度的增加,TNF-α和IL-10水平呈剂量依赖性降低,但各实验组明显高于空白对照组而低于阳性对照组(P0.05)。TGF-β在阳性对照组虽稍有升高,但与空白对照组相比无显著差异(P0.05)。而随着罗米地辛浓度的增加,TGF-β水平呈剂量依赖性升高,3实验组间及与空白对照组、阳性对照组间差异显著(P0.05)。结论:体外实验研究显示罗米地辛不仅能够有效抑制效应性T细胞的增殖,而且一定浓度的罗米地辛可上调调节性T细胞的比例,这可能与TGF-β升高有关,而与IL-10变化无关。     

同型半胱氨酸对小鼠卵母细胞成熟过程中组蛋白表观遗传修饰的影响

目的 探讨卵母细胞发育过程中同型半胱氨酸（HCY）对组蛋白表观遗传修饰的影响。 方法 首先使用10只2周ICR雌性小鼠建立完整卵泡的体外培养体系,在卵母细胞发育早期,利用免疫组织化学方法,观察HCY对甲基化组蛋白H3K4、H3K9以及乙酰化组蛋白H3K9分布的影响;其次使用10只4周ICR雌性小鼠,利用卵母细胞的体外成熟培养体系,观察HCY对卵母细胞成熟过程的影响,同时利用实时定量PCR方法,观察在此成熟过程中HCY对卵母细胞内组蛋白乙酰化水平的调控酶GCN5和HDAC表达的影响。 结果 HCY明显抑制卵母细胞的体外成熟,在HCY作用下,甲基化组蛋白H3K4、H3K9以及乙酰化组蛋白H3K9的分布没有变化,但是表达强度降低,核呈现去浓缩的趋势。成熟过程中HCY并不改变基因GCN5的表达水平,却明显抑制卵母细胞内HDAC基因的表达。 结论 卵母细胞发育过程中高水平的同型半胱氨酸影响组蛋白的表观遗传修饰,HCY对卵母细胞核内组蛋白甲基化和乙酰化修饰的影响有可能是造成核染色体稳定性下降的重要原因。     

Rapid histone deacetylation and transient HDAC association in the IL-2 promoter region of TSST-1-stimulated T cells

It remains unclear how superantigen induces unresponsiveness in stimulated T cells. We analyzed the chromatin status of the interleukin-2 (IL-2) promoter region in T cells stimulated with toxic shock syndrome toxin-1 (TSST-1) superantigen using T cell receptor-transgenic T cells responding to ovalbumin (OVA) and TSST-1. Compared to OVA stimulation, na?ve T cells cultured with TSST-1 showed lower IL-2 expression after transient enhancement. Coincidentally, the acetylated histone H3 (AcH3) level at the IL-2 promoter region was first enhanced, and then decreased, in TSST-1-stimulated T cells. At the reduction stage of AcH3, histone deacetylase-1 (HDAC1) was markedly associated with the IL-2 promoter region in a TSST-1-specific manner without HDAC1 over-expression. The enhancement of HDAC1 association and IL-2 suppression was prevented by pre-treatment with HDAC inhibitor, but not once the anergy status was established. These results suggest that recruitment of HDAC1 in the IL-2 promoter region at the early stimulation stage with TSST-1 plays a pivotal role in sAg-induced anergy.     

Inactivation of BRM/SMARCA2 sensitizes clear cell renal cell carcinoma to histone deacetylase complex inhibitors

BRM, a key subunit of the SWI/SNF chromatin remodeling complex, is an important tumor suppressor gene in multiple tumors. BRM is not mutated, but rather epigenetically silenced in a variety of tumor types, which is different from many anti-cancer genes. In addition, histone deacetylase complex (HDAC) inhibitors are known to reverse BRM silencing, but they also inactivate it via acetylation of its c-terminus. HDAC inhibitors have been reported to be effective at pharmacologically restoring BRM and thereby inhibiting cancer cell growth. But we do not know which HDAC inhibitor, if any, regulate BRM in clear cell renal cell carcinoma (RCC). By using seven types of HDAC inhibitors, we found that Pan-HDAC inhibitors restored BRM protein expression. Despite their ability to restore BRM expression, these HDAC inhibitors also blocked BRM function when present. However, after their removal, we observed that BRM expression remained elevated for several days, and during this period, BRM activity was detected. In addition, HDAC3 and HDAC9 regulate BRM expression and function, especially for HDAC3 inhibitor, RGFP966. Our study demonstrated that knockdown of BRM promoted RCC cells proliferation, migration and invasion. RGFP966 inhibited the tumor progression of clear cell RCC by restoring BRM expression both in vivo and in vitro. In conclusion, HDAC3 is potential targets for clinical treatment, and our study provides a new approach for targeted therapy of BRM-negative clear cell RCC.     

Islet-1 在乙酰化调控网络中特异性辅助C3H10T1/2细胞向心肌样细胞分化

 目的 筛选并分析转染Islet-1慢病毒载体的C3H10T1/2细胞转化为心肌样细胞过程中与Islet-1 相互作用的组蛋白乙酰化酶（HATs）和组蛋白去乙酰化酶（HDACs）,明确Islet-1在C3H10T1/2细胞分化为心肌样细胞乙酰化调控网络中的关键枢纽作用。方法 培养转染Islet-1慢病毒载体的C3H10T1/2细胞,观察细胞形态。免疫荧光和免疫印迹检测Islet-1的表达部位和最高表达时间点。免疫共沉淀沉淀与Islet-1结合的蛋白。免疫印迹验证Islet-1 相互作用的HATs和HDACs。结果 诱导组细胞形态出现心肌样细胞改变。各组Islet-1主要在胞浆表达。诱导组Islet-1表达量在诱导后3周最高（0.782±0.015）。诱导组Islet-1表达量显著高于空白对照组和C3H10组（分别为0.819±0.026,0.127±0.006和0.126±0.001）（P<0.05）,免疫共沉淀技术可行。与Islet-1相互作用的HATs和HDACs有GCN5、P300/CBP和HDAC4。结论 Islet-1 与GCN5、P300/CBP和HDAC4相互作用特异性辅助C3H10T1/2细胞向心肌样细胞分化。     

Effect of histone deacetylase inhibitors on the cell nucleus and nucleolus of leukemic myeloblasts in vitro - a cytochemical study

The present study was designed to provide complementary information on the effects of histone deacetylase inhibitors (HDACi's) such as trichostatin A (TSA) and sodium valproate (VAP) on nuclei and nucleoli of leukemic myeloblasts represented by cultured Kasumi-1 cells. The number of apoptotic cells and bodies with characteristic chromatin condensation and fragmentation was greater after TSA treatment. However, in contrast to TSA, myeloblasts treated with VPA recovered and started to proliferate again. TSA-treated myeloblasts with a fine chromatin structure exhibited an intense phagocytosis of cell fragments. The decreased number and translocation of silver-stained proteins of nucleolus organiser regions (AgNORs) in large nucleoli of myeloblasts treated with HDACi's indicated that these cells entered apoptosis and/or ageing without preceding terminal maturation. The nucleolar asynchrony observed in an increased number of treated cells with both HDACi's studied here possibly represented myeloblasts resistant to such treatment. In conclusion, this study demonstrates that the chromatin structure and nucleoli visualised by simple cytochemical procedures provides useful information on the effects of HDACi's on myeloblasts and facilitated detection of these effects at the single cell level.     

Class I and II histone deacetylase inhibition by ITF2357 reduces SLE pathogenesis in vivo

We sought to determine if a specific class I and II HDAC inhibitor (ITF2357) was able to decrease disease in lupus-prone NZB/W mice through regulation of T cell profiles. From 22 to 38 weeks-of-age, NZB/W and non-lupus NZW mice were treated with ITF2357 (5 mg/kg or 10 mg/kg), or vehicle control. Body weight and proteinuria were measured every 2 weeks, while sera anti-dsDNA and cytokine levels were measured every 4 weeks. Kidney disease was determined by sera IgG levels, immune complex deposition, and renal pathology. T lymphocyte profiles were assessed using flow cytometric analyses. Our results showed that NZB/W mice treated with the 10mg/kgof ITF2357 had decreased renal disease and inflammatory cytokines in the sera. Treatment with ITF2357 decreased the Th17 phenotype while increasing the percentage of Tregs as well as Foxp3 acetylation. These results suggest that specific HDAC inhibition may decrease disease by altering T cell differentiation and acetylation.     

Biology of Dendritic Cells in Aging

Dendritic cells are central to the generation of both immunity and tolerance. This review focuses on the alterations in the functions of dendritic cells in aged and its consequences on both tolerance and immunity. We have discussed certain mechanisms responsible for the defective dendritic cell function associated with aging.     

Dendritic cell functions: Learning from microbial evasion strategies

Dendritic cells (DCs) are specialized antigen presenting cells (APC) that are fundamental to initiate both immunity and tolerance. DCs play a ‘sentinel’ role to protect our body from potential pathogens and induce tolerogenic responses toward harmless antigens. The flexibility of DCs or macrophages to adapt to the environment and to respond accordingly can be hijacked by pathogens for their own interest to transform a potentially immunogenic APC into a tolerogenic cell with clear consequences in pathogen clearance. While these immune evasion mechanisms can be detrimental for the host, they can highlight important molecular pathways in DCs necessary for their function. In this review we will mention several mechanisms employed by pathogens to evade DC patrolling function.     

Increased expression of histone deacetylase 2 is found in human gastric cancer

Accumulated evidence has established that aberrant regulation of histone deacetylases (HDACs) is one of the major causes of the development of human malignancies. Among different iso-enzymes of HDAC and sirtuins grouped as the HDAC super family, little is known as to how histone deacetylase 2 (HDAC2) causes carcinogenesis in solid tumors. Here, in order to investigate the possible role of HDAC2 in gastric carcinogenesis, we analyzed the expression of HDAC2 in 71 gastric adenocarcinomas by immunohistochemistry. Moderate to strong expression of HDAC2 was found in 44 (62%) out of a total of 71 tumors. The majority of positive tumors, which were detected in the nucleus but not in normal gastric epithelium, did not express HDAC2 or showed only weak positive staining. Interestingly, we also noted that HDAC2 expression appeared to be associated with tumor aggressiveness as HDAC2 expression was observed to be statistically significant in advanced gastric cancer (P=0.0023, Chi-square test) and in positive lymph node metastasis (P=0.0713, Chi-square test). Taken together, these results suggest that HDAC2 may play an important role in the aggressiveness of gastric cancer.     

不同细胞因子诱导的小鼠骨髓树突状细胞亚群与小鼠脾脏树突状细胞亚群的比较

目的对粒-单集落刺激因子(GM-CSF)/白介素4(IL-4)或脱氧氟胸腺嘧啶配体(Flt3-L)体外诱导的小鼠骨髓来源树突状细胞(BMDC)亚群和正常小鼠脾脏DC亚群进行比较,探索诱生DC的特性。方法分离Balb/c小鼠骨髓细胞,分别加入含GM-CSF/IL-4或Flt3-L的培养液,体外培养7d,倒置显微镜观察细胞形态,并用流式细胞术检测CD11c、MHCⅡ、CD4、CD8α、CD45RA及Sirp-α分子;利用免疫磁珠从小鼠脾脏细胞中分离DC。结果两组细胞因子均可在体外诱导小鼠骨髓细胞分化发育为未成熟的DC;倒置显微镜下观察可见BMDCs表面有树突状突起,具有典型的DC形态学特点,与Flt3-L诱导的BMDC相比GM-CSF/IL-4诱导的DC体积大,树突长;但是,流式细胞术检测发现Flt3-L体外诱导的BMDCs与小鼠脾脏DC亚群更为相似。结论 GM-CSF/IL-4及Flt3-L均可在体外诱导小鼠骨髓细胞分化发育为DC,且Flt3-LDC亚群与脾脏DC亚群相似,有可能成为体外研究脾脏来源DC的一种方法。     

DNA甲基转移酶1和组蛋白去乙酰化酶1在子宫内膜异位症在位内膜的表达

目的 探讨DNA甲基转移酶1（DNMT1）和组蛋白去乙酰化酶1（HDAC1）在子宫内膜异位症患者子宫内膜中的表达及其两者在子宫内膜异位症发生、发展中的作用。方法 选取子宫内膜异位症患者在位内膜18例, 无子宫内膜异位症的对照子宫内膜20例,应用免疫组织化学法测定DNMT1的分布,应用免疫印迹法检测内膜组织中DNMT1和HDAC1蛋白的表达。结果 免疫组织化学提示,DNMT1主要分布于子宫内膜腺上皮细胞和间质细胞的胞核;子宫内膜异位症在位内膜中DNMT1的表达强度显著高于对照组子宫内膜（P<0.01）。免疫印迹发现,子宫内膜异位症在位内膜DNMT1和HDAC1蛋白的表达高于对照组子宫内膜, 差异有统计学意义（P<0.05）;且两者的表达呈正相关 （P<0.05）。结论 DNMT1和HDAC1在EMs患者的高表达可能在子宫内膜异位症的发生、发展中起着重要作用。