SMAD7

引言胶质母细胞瘤是最致命的恶性肿瘤之一，表现出明显的肿瘤内异质性，其中胶质母细胞瘤干细胞（GSCs）对肿瘤发生和治疗抵抗起着重要作用。泛素连接酶和去泛素化酶的药物调节剂正在开发用于癌症和其他疾病。2024年3月19日，西湖大学谢琦，深圳湾实验室李磊和匹兹堡大学Jeremy N. Rich共同通讯在Cell Discovery 发表题为“RBBP6 maintains glioblastoma stem cells through CPSF3-dependent alternative polyadenylation”的研究论文。该研究进行了并行的体外和体内CRISPR/Cas9敲除筛选，针对人类泛素E3连接酶和去泛素化酶，揭示了E3连接酶RBBP6作为GSC维持的一个必需因子，靶向RBBP6抑制了GSC的增殖和肿瘤起始。在机制上，RBBP6介导CPSF3的K63-链接泛素化，稳定了CPSF3来调节选择性多腺苷酸化事件。RBBP6敲除导致MYC竞争性内源性RNA的3'UTR缩短，从而释放了miR-590-3p从缩短的UTRs中，从而降低了MYC的表达。用小分子抑制剂（JTE-607）靶向CPSF3可以减少GSC的存活率并抑制体内肿瘤生长。总的来说，RBBP6通过调节CPSF3依赖的选择性多腺苷酸化在GSC中维持高MYC表达，为胶质母细胞瘤提供了一个潜在的治疗范例。胶质母细胞瘤是最常见和致命的原发性脑肿瘤，中位生存时间不到两年。目前胶质母细胞瘤的标准治疗包括最大程度的手术切除，联合放疗和化疗，随后进行辅助化疗，只能提供姑息治疗。胶质母细胞瘤表现出肿瘤内异质性，其中自我更新的胶质母细胞处于层级顶端。胶质母细胞以其自我更新和肿瘤起始能力而功能特异化，此外还对肿瘤血管生成、放射抵抗力和化疗抵抗力有额外的贡献。胶质母细胞瘤是最早进行全面遗传分析的肿瘤之一，揭示了导致信号传导失调的频繁变异，包括涉及表观遗传学变化、转录调节因子和转录后调节的变异。然而，基于遗传突变的精准医学对胶质母细胞瘤患者的临床管理影响有限，表明替代的分子靶点可能提供治疗益处。泛素化是调节底物蛋白命运和/或功能的最常见的翻译后修饰之一。泛素-蛋白酶体通路维持大多数蛋白质的稳态。泛素分子通过涉及E1（泛素激活）、E2（泛素连接）和E3（泛素连接酶）酶的催化级联添加到靶标蛋白中，可以通过去泛素化酶（DUBs）逆转。先前的研究已将泛素途径与胶质母细胞瘤的生长总体和GSC的维持特异性联系起来。例如，胶质母细胞瘤可能过表达USP15，该酶结合SMAD7-SMAD特异性E3泛素蛋白连接酶2（SMURF2）复合物去泛素化并稳定型I转化生长因子-β受体（TβR-I），增强TGF-β信号传导。在GSCs中，USP9x取消乙醛脱氢酶1A3（ALDH1A3）的多泛素化以稳定ALDH1A3并维持GSCs。用USP9x抑制剂WP1130处理GSCs可诱导ALDH1A3降解并抑制GSC的生长。此外，USP13和FBXL14相互调节GSCs中MYC的多泛素化。因此，去泛素化酶和泛素连接酶可能是胶质母细胞瘤的潜在治疗靶点。模式图（Credit: Cell Discovery）CRISPR/Cas9基因敲除（KO）高通量筛选已被证明是癌症治疗中目标基因发现的有效平台。先前的CRISPR筛选研究主要集中在体外培养的细胞模型上，这些模型无法充分代表肿瘤微环境的复杂效应，这种方法可能限制了药物开发的成功。在这里，作者改进了一种更具生理学相关性的体内CRISPR筛选方法，以识别对GSC维持和肿瘤形成至关重要的泛素连接酶和去泛素化酶。原文链接https://doi-org.libproxy1.nus.edu.sg/10.1038/s41421-024-00654-3责编|探索君排版|探索君文章来源|“iNature”End往期精选围观一文读透细胞死亡(Cell Death) | 24年Cell重磅综述（长文收藏版）热文Nature | 破除传统：为何我们需要重新思考肿瘤的命名方式热文Nature | 2024年值得关注的七项技术热文Nature | 自身免疫性疾病能被治愈吗？科学家们终于看到了希望热文CRISPR技术进化史 | 24年Cell综述

过敏性疾病是一组由于机体免疫系统对环境中典型无害物质产生的超敏反应性疾病，全世界大概有20%的人患有过敏性疾病，包括过敏性鼻炎、特应性皮炎、过敏性哮喘、食物过敏和严重过敏反应等。过敏性疾病的一个主要特征是免疫球蛋白E（IgE）抗体的产生，但目前调节IgE产生的机制尚不清楚。前期的流行病学研究表明，母乳中的转化生长因子（TGFβ）可以预防过敏性疾病的发生，动物实验研究还表明，TGFβ的减少会加重小鼠的过敏性哮喘以及IgE抗体的表达。总的来说，这些研究表明TGFβ通路在过敏的发病机制中发挥着关键作用。然而，所涉及的具体机制还尚不清楚。因此，美国科学家以罕见病洛伊-迪茨综合征（Loeys-Dietz syndrome，LDS）患者和LDS小鼠模型（Tgfbr1WT/mut）为研究对象，研究TGFβ信号传导如何调节过敏性疾病中IgE的产生。相关研究结果“TGFβ prevents IgE-mediated allergic disease by restraining T follicular helper 2 differentiation”于2024年1月发表在Science Immunology 杂志上。研究结果发现，TGFβ可通过PI3Kγ/mTOR途径抑制TFH2的分化和IgE的产生来预防过敏性疾病。 DOI：10.1126/sciimmunol.adg8691患有过敏性罕见疾病洛伊-迪茨综合征（LDS）的患者通常是由于TGFBR1/2中高度保守的激酶结构域的错义突变引起的。研究人员发现，在过敏反应达到高峰时，LDS患者以及Tgfbr1WT/mut小鼠CD4+T细胞中pSmad2/3水平（TGFβ信号转导的标志物）显著低于健康对照组(Healthy volunteer，HV)。同时在TGFβ刺激后，来自非综合征性过敏患者的CD4+T细胞中的pSmad2/3表达量有所降低。这些数据表明，LDS患者、Tgfbr1WT/mut小鼠以及非综合征性过敏患者的CD4+T细胞中TGFβ信号传导有所受损。研究者对LDS患者和Tgfbr1WT/mut小鼠的体液反应进行检测后发现，大多数LDS患者对常见环境和食物中的过敏原会产生特异性IgE抗体，同时小鼠中也存在这样的现象，因此研究人员推测，TGFβ信号传导的减弱与2型体液免疫反应中血浆总IgE和食物抗原特异性IgE的产生有关。图1. T 细胞中TGFβ信号传导与血清 Igs 的关系生发中心（Germinal center,GCs）是淋巴器官繁殖、分化以及抗体基因变异的区域。在机体发挥正常免疫功能对抗感染时，抗体在生发中心会改变它们的类别，例如从IgM变成IgG。其中肠系膜淋巴结(mLN)和派尔氏淋巴结(PP)含有丰富的生发中心。因此，研究人员对Tgfbr1WT/mut小鼠mLN和PP的GCs和TFH2进行分析，发现尽管Tgfbr1WT/mut小鼠PP的总体结构、组织与WT小鼠无区别，但是Tgfbr1WT/mut小鼠PP中的GCs区域比WT的大，同时发现在Tgfbr1WT/mut小鼠的PP、mLN和脾脏中，产生IL-4的TFH2效应细胞在促进IgE产生中发挥着关键作用。这说明TGFβ在Tgfbr1WT/mut小鼠中，对调节GC反应以及TFH对抗原的反应中发挥着潜在的作用。对LDS患者进行研究发现，其记忆CD4+T细胞、CD4+TFH细胞和浆母细胞显著增加，其TFH2细胞选择性增加，TFH17细胞减少。说明LDS患者和小鼠中的TFH2和GC活性有所增加。为了探究T细胞中TGFβ信号减弱导致TFH分化的机制，研究人员从Tgfbr1WT/mut和WT小鼠的PP中分选出TFH细胞，并进行了RNA-seq分析。发现Tgfbr1WT/mut小鼠的TFH细胞中有240个基因上调，228个基因下调，包括Smad7、Sardh、Ctsw、Rgs10、Apol9a/b、Ctnna1、Skil和Kras-。总之，这些数据表明TGFβ信号传导的部分丧失会导致TFH转录特征增强，并且TGFβ信号传导在TFH细胞中具有重要作用。对WT和Tgfbr1WT/mut小鼠TFH细胞之间差异表达的基因进行独创途径分析（Ingenuity pathways analysis，IPA），发现Tgfbr1WT/mut小鼠的TFH细胞中，IL-4、IL-4信号、TH1和TH2以及TH2途径被激活，PI3K脂质激酶表达量上调，PI3K信号通路及其通路下游的p70S6信号通路被激活。这些数据表明Tgfbr1WT/mut小鼠TFH细胞中PI3K/mTOR信号传导增强，并且TFH发育至关重要的下游途径也有所上调。图2. Tgfbr1WT/mut小鼠TFH细胞中PI3Kγ/mTOR信号通路的增强为了研究抑制体内PI3Kγ/mTOR通路是否可以阻止Tgfbr1WT/mut小鼠中TFH细胞的过度生成。研究人员将WT或Tgfbr1WT/mut OTII细胞移植至CD45.1 WT宿主中，并将OVA饲养8天，并在第3天至7天腹膜注射PI3Kγ抑制剂伊加内利西布。发现PI3Kγ通路的抑制，显著抑制了OVA特异性Tgfbr1WT/mut 小鼠的TFH细胞积累。说明TGFβ通过靶向T细胞中的PI3Kγ/mTOR通路，成为了TFH2分化过程中重要的调节因子，并且该通路的破坏会导致TFH2分化异常，从而对对食物抗原过敏。本研究揭示了LDS患者中IgE介导的过敏性疾病的机制，并表明TFH细胞是IgE介导过敏性疾病的关键参与者。不仅如此，还揭示了TGFβ通路中遗传变异与过敏性疾病的关联，并发现了T细胞TGFβ信号传导在预防异常TFH和GC活性方面的关键作用，为深入了解TGFβ在过敏性疾病发病机制提供了强有力的证据。参考文献：Haque, T. T., Weissler, K. A., Schmiechen, Z., Laky, K., Schwartz, D. M., Li, J., Locci, M., Turfkruyer, M., Yao, C., Schaughency, P., Leak, L., Lack, J., Kanno, Y., O'Shea, J., & Frischmeyer-Guerrerio, P. A. (2024). TGFβ prevents IgE-mediated allergic disease by restraining T follicular helper 2 differentiation. Science immunology, 9(91), eadg8691. https://doi-org.libproxy1.nus.edu.sg/10.1126/sciimmunol.adg8691撰文 | Shmily编辑 | lcc部分文字来源于网络，本文仅用于学术分享，转载请注明出处。若有侵权，请联系微信：bioonSir 删除或修改！

SAN DIEGO, Nov. 13, 2023 (GLOBE NEWSWIRE) -- Gyre Therapeutics (“Gyre”) (NASDAQ: GYRE), a clinical-stage biotechnology company developing anti-fibrotic therapeutics for a variety of chronic liver diseases, today announced the presentation of a poster at the American Association for the Study of Liver Diseases’ (AASLD) Annual Liver Meeting, November 10-14, 2023, in Boston, Massachusetts. Gyre’s lead asset, Hydronidone, is currently being investigated for the treatment of Metabolic Dysfunction Associated Steatohepatitis (MASH)-associated liver fibrosis in the United States. Gyre’s poster presented the potential antifibrotic effects of Hydronidone and its expected mode of action in mouse hepatic fibrosis models. “We are encouraged by these preclinical results that support Hydronidone’s candidacy as a potential treatment for liver fibrosis,” said Charles Wu, Ph.D., Chief Executive Officer of Gyre Therapeutics. “Our team and collaborators showed Hydronidone’s ability to ameliorate liver fibrosis by inhibiting the activation of hepatic stellate cells (HSCs) via Smad7-mediated Tumor Growth Transforming (TGF)- degradation. Activation of the HSCs is recognized as a central event in the process of liver fibrogenesis with the TGF as one of the key mediators. The obtained mechanistic data support the potential of Hydronidone for the treatment of liver fibrosis associated with a spectrum of chronic liver diseases. We look forward to initiating the clinical program of Hydronidone in the United States in 2024.” Key highlights from the poster presentation are below: Hydronidone significantly improved liver damage in carbon tetrachloride (CCL4) and 3,5-diethoxycarbonyl-1,4-dihydropyridine (DDC) mouse hepatic fibrosis models and reduced the accumulation of collagenHydronidone inhibited the activation of hepatic stellate cells via Smad7-mediated TGF- degradation and decreased the expression of fibrosis genes in hepatic stellate cellsIn a ubiquitin-proteasome dependent pathway, Hydronidone promoted the Caveolin-1 mediated TGFβRI degradation via Smad7Specific knockdown of Smad7 in vivo blocked the antifibrosis effect of Hydronidone Full details for the poster presentations are below: Title: Hydronidone ameliorates liver fibrosis by inhibiting activation of hepatic stellate cells via Smad7-mediated degradation of TGFβRIPresenting Authors: Xianjun Xu, Department of Gastroenterology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, ChinaPoster Number: 3417-A Date and Time: Sunday, November 12, 2023 from 1:00 p.m. to 2:00 p.m. ETLocation: Poster Hall A A copy of the poster will be made available on the Gyre website at www.gyretx.com following the conclusion of the meeting. About Gyre Therapeutics Gyre Therapeutics (“Gyre”) is a biopharmaceutical company headquartered in San Diego, CA, with a primary focus on the development and commercialization of Hydronidone (F351) for the treatment of Metabolic Dysfunction Associated Steatohepatitis (MASH)-associated fibrosis, formerly known as Nonalcoholic Steatohepatitis (NASH) in the United States. Hydronidone’s development strategy in MASH is based on results obtained in mechanistic studies in MASH rodent model and results of a chronic Hepatitis-B induced liver fibrosis Phase 2 clinical study in China which met the primary endpoints of safety and efficacy and led recently to the designation of a breakthrough therapy by the New Medicines Product Administration of China (NMPA). Gyre is also advancing a diverse pipeline China through its indirect controlling interest in Beijing Continent Pharmaceuticals Ltd., Co., including pirfenidone, F573, F528, and F230. Forward-looking Statements This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, which statements are subject to substantial risks and uncertainties and are based on estimates and assumptions. All statements, other than statements of historical facts included in this press release, including statements concerning the progress and future expectations and goals of Gyre’s research and development efforts, including the timing of the clinical program of Hydronidone, are forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “may,” “might,” “will,” “objective,” “intend,” “should,” “could,” “can,” “would,” “expect,” “believe,” “design,” “estimate,” “predict,” “potential,” “plan” or the negative of these terms, and similar expressions intended to identify forward-looking statements. These statements reflect our plans, estimates, and expectations, as of the date of this press release. These statements involve known and unknown risks, uncertainties and other factors that could cause our actual results to differ materially from the forward-looking statements expressed or implied in this press release. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation: risks associated with the possible failure to realize certain anticipated benefits of the business combination with Catalyst Biosciences, Inc., including with respect to future financial and operating results; positive results from a clinical study may not necessarily be predictive of the results of future or ongoing clinical studies; competition from competing products; the impact of general economic, health, industrial or political conditions in the United States or internationally; the sufficiency of Gyre’s capital resources and its ability to raise additional capital. Additional risks and factors are identified under “Risk Factors” in Gyre’s Annual Report on Form 10-K filed on March 30, 2023 and subsequent reports filed with the SEC, and identified under “Risk Factors” in the Proxy Statement. Gyre expressly disclaims any obligation to update any forward-looking statements whether as a result of new information, future events or otherwise, except as required by law. For Investors: Stephen Jasper stephen@gilmartinir.com