RNA N6-甲基腺苷(m6A)修饰相关酶在哺乳动物精子发生中的研究进展

N6-甲基腺苷(m6A)核酸修饰是近10年来研究较多的一类表观修饰，RNA通过经典m6A修饰蛋白“Writers”(METTL3/14/WTAP等)、m6A去修饰蛋白“Erasers”(FTO和ALKBH5)和m6A识别蛋白“Readers”(YTHDC1/2、YTHDF1/2/3等)组成的协同调节体系进行转录后核酸m6A修饰、去修饰和识别结合，进而调控转录本下游命运。精子发生是雄性哺乳动物性成熟和维持生育能力的重要过程，涉及生精上皮支持细胞、间质细胞和精原细胞等增殖分化和维持生精微环境过程。多项研究表明m6A调节体系参与哺乳动物精子发生进程，异常的m6A修饰水平和m6A调节体系失衡均会导致睾丸发育异常、精子发生异常和雄性不育。本文综述了精子发生过程中m6A修饰相关酶的作用，深入分析m6A差异修饰转录本之于正常精子发生的作用，对认知哺乳动物精子发生和解析临床生精障碍的分子机制具有重要意义。     

m6A-SNPs及其在复杂疾病分子遗传学研究中的应用

N6-甲基腺苷(N6-methyladenosine, m6A)是真核生物mRNA最常见的一种转录后修饰, 在多种生物过程中具有关键作用。有研究表明单核苷酸多态性(single nucleotide polymorphism, SNP)可以通过改变靶基因基序影响其m6A修饰, 进而对疾病的发生发展产生影响。随着高通量测序技术的不断发展, 越来越多的可能影响m6A修饰的SNPs(m6A-SNPs)被鉴定出来。文章主要就m6A-SNPs在复杂疾病分子遗传学研究中的进展进行综述。     

类甲基化转移酶3(METTL3)在免疫细胞和造血干细胞中的作用研究进展

腺嘌呤第6位氮原子上发生的甲基化修饰(m~6A)是真核生物mRNA中最常见的甲基化修饰,m~6A作为一种动态可逆修饰,参与众多生物学过程。类甲基化转移酶3(METTL3)是构成m~6A甲基转移酶复合体的核心组分,负责催化RNA发生m~6A修饰。近年的研究发现,METTL3通过调控m~6A水平,调节T淋巴细胞的分化和功能的维持、巨噬细胞的活化和极化以及树突状细胞的激活等过程,进而调控免疫反应和有关疾病的发生和发展;同时很多研究也报导,METTL3在内皮造血转化、造血干细胞的自我更新、增殖分化以及细胞周期调控方面也具有重要作用,这为临床上治疗血液系统的有关疾病提供了新思路。     

N6-甲基腺苷(m6A)RNA修饰在生殖系统疾病中作用的研究进展

N6-甲基腺苷(m6A)RNA修饰是发生在RNA腺嘌呤第6位N原子上的一种转录后的甲基化修饰,调控mRNA的结构、稳定性、剪接、输出、转译和衰变等,进而广泛影响各种生物的生命过程。本文总结了在生殖系统疾病及乳腺癌发生发展过程中各种m6A甲基化酶的作用及机制,旨在为生殖系统疾病及乳腺癌早期诊断、治疗及预后判断提供新的依据。     

RNA m6A甲基化调控免疫细胞的研究进展

表观遗传通过调控免疫细胞功能, 参与肿瘤、感染及炎症等疾病的发生发展。N6-甲基腺嘌呤(N6-methyladenosine, m6A)是表观遗传中最常见的RNA甲基化修饰。m6A由三种甲基修饰蛋白参与, 通过共同调控靶分子RNA转录、剪接、降解、翻译和稳定等发挥重要生物学功能。异常m6A修饰与炎症、癌症和自身免疫性疾病等相关。文章主要综述m6A修饰在免疫细胞中的调控作用、分子机制以及与免疫治疗的关系。     

FTO介导RNA的m6A修饰与发育的研究进展

人类脂肪和肥胖相关蛋白FTO作为第一个被确证的N⁶-甲基腺苷(m6A)去甲基化酶,证明了RNA修饰存在可逆性,同时也揭开了m6A修饰的研究序幕。越来越多的学者试着从m6A修饰角度探讨基因表达调控的具体机制。m6A修饰功能需要甲基化酶、去甲基化酶、结合蛋白的共同参与完成。FTO可催化mRNA上m6A修饰的去甲基化,且在人体组织中广泛表达并参与调控多种生物学过程。本文综述去甲基化酶FTO及其介导的m6A/RNA修饰与体脂发育、胚胎发育、大脑发育、神经发育的关系,以期能够深入了解FTO的功能以及作用机制。     

m6A修饰在鳞状细胞癌中的作用研究进展

近年来,RNA表观转录组学已成为生命科学领域研究的热点.作为真核细胞中最丰富的表观转录组修饰,N6-甲基腺苷(N6-methyladenosine,m6A)修饰是一种动态且可逆的过程[1].研究表明,m6A可以通过调节RNA剪接、稳定性、定位、翻译和衰变,参与神经发育、免疫调节和细胞分化等各种生理行为.m6A修饰的失调...     

RNA m6A修饰参与乙型和丙型肝炎病毒复制及相关肝癌发生机制研究进展

RNA甲基化修饰是近几年表观遗传学研究的热点之一,N6-甲基腺苷(m6A)修饰是哺乳动物中RNA甲基化的最主要类型。最新研究发现RNA m6A甲基化修饰在肝炎病毒复制及相关肝癌发生发展中发挥重要作用。本文将对该方面最新研究进展进行综述,这将有利于为相关疾病的研究提供一定的理论依据和新的研究思路。     

miRNA-181b在氧-糖剥夺致N2A细胞缺血损伤中的作用及对热休克蛋白A5表达的调节

目的 探讨miR-181b在氧糖剥夺(OGD)致N2As神经瘤细胞缺血损伤中的作用,及其对热休克蛋白（HSP）A5表达的调节。方法 应用N2A细胞OGD模型模拟神经细胞缺血损伤,MTT比色法检测N2A细胞生存率,免疫印迹法检测HSPA5蛋白表达水平,实时定量PCR法检测miR-181b和HSPA5 mRNA表达水平,荧光素酶报告基因技术检测miR-181b对HSPA5 mRNA的直接调控作用。 结果 miR-181b在OGD致N2A细胞缺血损伤中表达水平明显降低(n=5);在OGD致N2A细胞缺血损伤过程中,通过上调或抑制miR-181b的表达水平可以显著影响N2A细胞的生存率(n=6);而在非OGD条件下,miR-181b表达水平的改变对N2A细胞活力无影响;miR-181b表达水平的改变可显著影响HSPA5蛋白表达水平(n=3),而非HSPA5的mRNA水平;共转染miR181b前体（pre-miR-181b）或miR-181b抑制剂（anti-miR-181b）可显著抑制或增高含有HSPA5 mRNA 3’-UTR的荧光素酶报告基因的活性(n=5)。 结论 miR-181b通过负性调节HSPA5的蛋白表达水平,在OGD致N2A神经细胞缺血性损伤中发挥重要作用。     

RNA m6A修饰在膀胱癌中的作用

近年来,RNA表观修饰引起了全球学者的重视.在所有已知的RNA修饰中,N6-甲基腺苷(N6-methyladenosine,m6A)修饰是主要的RNA修饰.作为一种动态且可逆的修饰,m6A被"作家蛋白"(RNA甲基转移酶)催化,被"橡皮擦蛋白"(去甲基酶)去除,并与"阅读蛋白"(m6A结合蛋白)相互作用,从而影响RNA...     

METTL3调控SPRING1促进巨噬细胞脂质蓄积

目的 探讨METTL3调控SPRING1促进巨噬细胞脂质蓄积的作用及机制。 方法 100 ng/mL PMA诱导THP-1细胞贴壁后,50 μg/mL Ac-LDL孵育THP-1细胞。Western blot测定METTL3和SPRING1蛋白;qRT-PCR测定SPRING1mRNA水平;细胞内总胆固醇、胆固醇酯以及游离胆固醇变化用高效液相色谱法检测;SRAMP和RMBase网站分析SPRING1 mRNA上的m6A修饰位点情况;质膜红色荧光标记探针Dil-Ac-LDL观察巨噬细胞脂滴摄取情况。 结果 与对照组相比,Ac-LDL孵育后THP-1细胞METTL3和SPRING1蛋白表达上调,并且SPRING1 mRNA水平上调;过表达METTL3会使SPRING1蛋白表达上调,巨噬细胞对脂质摄取增加,细胞内Dil-Ac-LDL明显增多;反之,沉默METTL3表达,SPRING1蛋白表达下调;甲基化抑制剂环亮氨酸处理可部分抑制METTL3过表达对SPRING1表达的促进作用;生物信息学分析显示,SPRING1 mRNA存在m6A修饰位点。 结论 METTL3上调SPRING1表达,促进巨噬细胞脂质蓄积。     

CTLA-4 regulates cell cycle progression during a primary immune response.

Engagement of CTLA-4 is critical for inhibiting T cell immune responses. Recent studies have shown that CTLA-4 plays a key role in regulating peripheral T cell tolerance. It has been suggested that one mechanism by which CTLA-4 performs this function is by regulating cell cycle progression. Here, we investigate in depth the role of CTLA-4 in regulating cell cycle progression in naive T cells by comparing the immune responses in the absence or presence of CTLA-4. In the absence of CLTA-4, T cells exhibit marked increases in T cell proliferation, IL-2 mRNA and protein secretion, and cells cycling in the S and G2-M phase. Analyses of cyclins, cyclin-dependent kinases, and cell cycle inhibitors involved in the transition from the G1 to S phase reveal that cell cycle progression is prolonged in the absence of CTLA-4. This is due to the early exit from the G1 phase, entry into the S phase, and prolonged S phase period. Re-expression of the cell cycle inhibitor p27(kip1) is delayed in the absence of CTLA-4. These studies demonstrate that the B7 : CTLA-4 pathway exerts its major effects on T cell immune responses via regulation of the cell cycle.     

Viral and non-viral approaches for transient delivery of mRNA and proteins

The transient delivery of gene products (RNA or proteins) is not a biotechnological invention but rather an evolutionarily conserved process underlying and regulating a variety of biological functions. On the basis of insights into the underlying mechanisms, several viral and cell-based approaches have been developed for the delivery of RNA or proteins. Prominent applications include the induction of major biological or therapeutic effects on the basis of "hit-and-run" mechanisms, such as vaccination, cell fate modification (reprogramming, differentiation), control of cell trafficking, enhancement of cell regeneration, and genome engineering using sequence-specific recombinases or nucleases. Ideally, procedures for delivery of RNA or proteins should be targeted to specific cells, overcome biophysical hurdles without harming cellular integrity, circumvent the various alarm signals of the innate immune system, allow dose-controlled delivery of functional biomacromolecules, and avoid the induction of an adaptive immune response. Here we review the current state of approaches for the delivery of mRNA and proteins with a focus on RNA viruses, virus-like particles including retrovirus particle-mediated transfer of mRNA or proteins, extracellular vesicles, and cell-penetrating peptides. The basic concepts and recent advances are put into perspective in the context of potential limitations of the technologies and strategies to overcome cellular barriers and defense mechanisms.     

The RNA m6A methyltransferase METTL3 promotes pancreatic cancer cell proliferation and invasion

Epigenetic modifications are involved in carcinogenesis and METTL3 is involved in RNA methylation. This study aimed to explore the role of the RNA m6A methyltransferase METTL3 in pancreatic cancer cells. The m6A modification was analyzed in human pancreatic cancer and paracancerous specimens, as well as in the normal HPDE6-C7 pancreatic cell line and the MIA-PaCa-2 and BxPC-3 pancreatic cancer cell lines. Immunohistochemistry (IHC), western blotting, and RT-qPCR were used to detect the expression of METTL3. Cell lines were transfected with siRNAs against METLL3. Proliferation, invasion, and migration were examined. The functions of METTL3 were predicted by bioinformatics analysis. In the 40 patients included, high METTL3 expression was associated with high pathological stage (P = 0.02) and high N stage (P = 0.02). Survival was better in patients with low METTL3 expression compared with those with high MTTL3 expression (P < 0.01). METTL3 and CIITA expression levels were inversely correlated (r = ?0.71, P < 0.01). RNA m6A content in tumor specimens was significantly higher than that in paracancerous specimens. METTL3 protein and mRNA levels were significantly higher in tumor specimens compared with paracancerous specimens, as well as in cancerous cell lines vs. normal cells. METTL3 knockdown in MIA PaCa-2 and BxPC-3 cells decreased RNA m6A modifications. Cell proliferation, invasion, and migration were decreased by METTL3 knockdown in cancerous cell lines. A total of 673 differentially expressed genes were identified by bioinformatics: 659 were upregulated and 14 were downregulated. In conclusion, METTL3 is probably involved in pancreatic carcinogenesis. It could eventually be a prognostic marker or a treatment target.     

Vasoactive intestinal peptide alleviates food allergy via restoring regulatory B cell functions

The immune regulatory cell dysfunction is associated with many immune diseases including food allergy (FA). This study aims to investigate the role of vasoactive intestinal peptide (VIP) in the maintenance of regulatory B cell (Br cell)'s immune suppressive functions by stabilizing thrombospondin (TSP1) expression. In this study, blood samples were collected from patients with food allergy (FA) and healthy control (HC) subjects. Br cells were isolated from the samples through flow cytometry cell sorting and analyzed by immunological approaches to determine the immune regulatory capacity. We found that the immune suppressive functions of Br cells were impaired in FA patients. The serum VIP levels were associated with the production of immune suppressive function-related mediators (interleukin-10, IL-10) of Br cells in FA patients. VIP counteracted IL-10 mRNA decay in Br cells by up regulating the TSP1 expression. TSP1 inhibited tristetraprolin (TTP) to prevent IL-10 mRNA decay in Br cells. Administration of VIP inhibited FA response through restoration of immune suppressive functions in Br cells. In conclusion, administration of VIP can alleviate FA response through up regulating expression of TSP1 to stabilize IL-10 expression in FA Br cells and recover the immune regulatory functions. The results have translational potential for the treatment of FA and other disorders associated with immune regulatory dysfunction of Br cells.     

炎症性肠病的自噬与表观遗传修饰

文题释义：自噬：是一个吞噬自身细胞质蛋白或细胞器并使其包被进入囊泡,并与溶酶体融合形成自噬溶酶体,降解其所包裹的内容物的过程,以此实现细胞本身的代谢需要和某些细胞器的更新。 表观遗传：是指DNA序列不发生变化,但基因表达却发生了可遗传的改变,主要包括DNA甲基化、组蛋白修饰、染色质重塑以及非编码RNA的调控,这种改变在细胞发育和增殖过程中能稳定的传递。 背景：炎症性肠病是一种与肠道自身免疫相关的慢性炎症性疾病,自噬是促进免疫调节的细胞途径,相关基因的表达异常与肠道炎症以及免疫反应关系密切,而表观遗传修饰对炎症性肠病自噬的调控机制尚未阐明。 目的：文章旨在对表观遗传修饰在炎症性肠病自噬中的调控作用作一介绍,以期探讨炎症性肠病自噬的发生机制。 方法：检索PubMed数据库,检索时限1998年1月至2019年4月,检索关键词为“inflammatory bowel disease,autophagy,autophagy related genes,epigenetic modification,DNA methylation,histone modification,chromatin remodeling,miRNA”,选择61篇符合标准的文献。 结果与结论：表观遗传(DNA甲基化、组蛋白修饰、染色质重塑、非编码RNA)可通过修饰炎症性肠病的易感基因ATG、IRGM等来调控肠道炎症、免疫以及自噬,从而介导炎症性肠病的发生和发展。 ORCID: 0000-0003-0627-9236(郭娅静) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

6A8 α-甘露糖苷酶基因的mRNA表达与染色体定位

目的 对6A8α－甘露糖苷酶基因作染色体定位,比较6A8α－甘露糖苷酶mRNA在人多种免疫细胞株的表达。方法 用Fish原位杂交作染色体定位,用RT－PCR检测mRNA表达。结果 6A8α－甘露糖苷酶基因定位于人第13号染色体长臂的31－32区。6A8α－甘露糖苷酶mRNA在B细胞株SKW6高表达,在B细胞株3D5、BJAB、DESS、Daudi、Nalm6中度表达,在B细胞株Navalm,T细胞株GM、Jurkat,细胞细胞瘤细胞株U937弱表达,在T细胞株Peer,慢性髓性白血病细胞株K562极弱表达。结论 6A8α－甘露糖苷酶基因定位于人第13号染色体长臂的31－32区,其mRNA表达水平在各种人免疫细胞株不同。     

Mice deficient in heparanase exhibit impaired dendritic cell migration and reduced airway inflammation

Heparanase is a β‐d ‐endoglucuronidase that cleaves heparan sulphate, a key component of the ECM and basement membrane. The remodelling of the ECM by heparanase has been proposed to regulate both normal physiological and pathological processes, including wound healing, inflammation, tumour angiogenesis and cell migration. Heparanase is also known to exhibit non‐enzymatic functions by regulating cell adhesion, cell signalling and differentiation. In this study, constitutive heparanase‐deficient (Hpse^?/?) mice were generated on a C57BL/6 background using the Cre/loxP recombination system, with a complete lack of heparanase mRNA, protein and activity. Although heparanase has been implicated in embryogenesis and development, Hpse^?/? mice are anatomically normal and fertile. Interestingly, consistent with the suggested function of heparanase in cell migration, the trafficking of dendritic cells from the skin to the draining lymph nodes was markedly reduced in Hpse^?/? mice. Furthermore, the ability of Hpse^?/? mice to generate an allergic inflammatory response in the airways, a process that requires dendritic cell migration, was also impaired. These findings establish an important role for heparanase in immunity and identify the enzyme as a potential target for regulation of an immune response.