Novel epigenetic therapy for Th17 cell mediated autoimmune inflammatory diseases.
Novel epigenetic therapy for Th17 cell mediated autoimmune inflammatory diseases.
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DOI：
10.1016/j.ebiom.2022.104368
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发表时间：
2022-12
期刊：
影响因子：
11.1
通讯作者：
Chu, Wai Kit
中科院分区：
文献类型：
--
作者：
Ho, Bo Man;Du, Lin;Chu, Wai Kit
免疫发病机制导致多种器官的自身免疫性和炎症性疾病，临床表现各异。眼睛会受到严重影响。一种常见的眼部自身免疫性并发症，自身免疫性葡萄膜炎，可导致不可逆的失明。目前治疗自身免疫性葡萄膜炎的一线方法是皮质类固醇。然而，一些患者对类固醇没有反应。一些接受类固醇治疗的患者可能出现全身和眼部副作用，如骨质疏松症、白内障和青光眼。使用生物制剂是这些患者替代类固醇的另一种治疗方法，但葡萄膜炎发病机制的复杂性阻碍了这些替代药物的有效性。生物制剂开发的新靶点仍然是迫切需要的。CD4+ T辅助细胞（Th）通过引发适应性免疫反应在自身免疫中起关键作用。不同的Th细胞系通过不同的极化机制对特定的致病因子表现出特定的宿主防御反应，这些极化机制由细胞因子和表观遗传机制精确调节，包括组蛋白修饰、DNA甲基化、核小体重塑和染色质组织。先前有报道称DNA甲基转移酶抑制剂Zebularine和bromodomain以及外端（BET）蛋白抑制剂OTX015在实验动物模型中抑制Th17细胞介导的自身免疫性葡萄膜炎。5,6尽管这些药物表现出不理想的全身毒性和不理想的特异性，但它们表明表观遗传学作为自身免疫性葡萄膜炎的新治疗方法的临床适用性。在最近一期的《电子生物医学》杂志上，Hu等人提出了一种新的自身免疫性葡萄膜炎的表观遗传学治疗方法。研究小组从128种表观遗传抑制剂中确定了5种潜在的候选药物，它们在自身免疫性葡萄膜炎实验动物模型中抑制Th1细胞中IFN-γ的表达和Th17细胞中IL-17的表达，而不影响细胞活力。IOX1是2-氧戊二酸（2OG）依赖性加氧酶的抑制剂，由于其对Th17细胞的优先抑制作用，可以减轻免疫反应。RNA-seq和qPCR分析显示，IOX1处理不影响Th17分化的上游转录因子。相反，观察到Th17下游特征细胞因子Il17a和Ccl20的表达受到抑制，表明IOX1对Th17分化具有直接调节作用。通过细胞热移测定和生物层干涉法发现IOX1直接与TET2 DNA去甲基化酶相互作用。亚硫酸氢盐测序、染色质免疫沉淀和化学免疫沉淀显示IOX1直接结合到Il17a启动子的CpG-6-8位点，导致这些位点上的DNA去甲基化较少。采用TET2缺陷的CD4+ T细胞进一步验证了IOX1对Th17极化、IL-17和CCL20表达的抑制能力。为了研究IOX1和Th17在体内相互作用的影响，我们在实验性自身免疫性葡萄膜炎（EAU）动物模型中研究了IOX1的抗炎作用。IOX1治疗EAU小鼠的临床症状较溶剂对照组轻。此外，流式细胞术分析显示，全身给药IOX1可以显著减少眼内促炎T细胞群，但不影响全身T细胞。这项优雅的研究描述了一种涉及Th17细胞的表观遗传机制，其新发现的IOX1分子靶标通过直接靶向Th17细胞启动子上的TET2活性来抑制Il17a的表达。这种精细的分子机制有助于表观遗传治疗的发展。
Immunopathogenesis leads to autoimmune and inflammatory diseases of many organs with variable clinical manifestations. The eye can be seriously affected. A common ocular autoimmune complication, autoimmune uveitis, can lead to irreversible blindness. Currently the first line treatment for autoimmune uveitis is corticosteroids. 1 However, some patients do not respond to steroids. Some steroid treated patients may developed systemic and ocular side effects such as osteoporosis, cataract and glaucoma. 2 The use of biologics is an alternative treatment for these patients to replace steroids, but the complicated nature of the pathogenesis in uveitis hampers the effectiveness of these alternative agents. 3 New targets for biologics development are still in desperate need. CD4+ T helper (Th) cells play a crucial role in autoimmunity by eliciting adaptive immune responses. Various Th cell lineages exhibit specific host defense responses against specific pathogenic factors by various polarizing mechanisms that are precisely regulated by cytokines and epigenetic machinery including histone modifications, DNA methylation, nucleosome remodeling and chromatin organization. 4 Previously DNA methyltransferase inhibitor, Zebularine and bromodomain, and extra-terminal (BET) protein inhibitor, OTX015 have been reported to suppress the Th17 cell mediated autoimmune uveitis in experimental animal models. 5, 6 Although these drugs show undesirable systemic toxicity with suboptimal specificity, they indicate the clinical applicability of epigenetics as a novel treatment for autoimmune uveitis. 7, 8 In a recent issue of eBioMedicine, Hu et al. proposed a new epigenetic treatment for autoimmune uveitis. 9 The team identified five potential candidates from a pool of 128 epigenetic inhibitors that suppress expression of IFN-γ in Th1 cells and IL-17 in Th17 cells in the experimental animal model of autoimmune uveitis, without compromising cell viability. IOX1, an inhibitor of 2-oxoglutarate (2OG)-dependent oxygenases, could alleviate immunologic responses, because of its preferential inhibition of Th17 cells. RNA-seq analysis and qPCR revealed that upstream transcription factors of Th17 differentiation were not affected by IOX1 treatment. Conversely, suppression of the Th17 downstream signature cytokines Il17a and Ccl20 expression was observed, indicating a direct regulatory role of IOX1 on Th17 differentiation. IOX1 was found directly interacting with the TET2 DNA demethylase via cellular thermal shift assays and biolayer interferometry. Bisulfite sequencing, chromatin immunoprecipitation, and chemical-immunoprecipitation showed direct binding of IOX1 to the CpG-6-8 site in the Il17a promoter that led to less demethylated DNA on these sites. The adoption of TET2 deficient CD4+ T cells further validated the inhibitory ability of IOX1 towards Th17 polarization and IL-17 and CCL20 expression. To study the effects of the IOX1 and Th17 interaction in vivo, the anti-inflammatory efficacy of IOX1 was investigated in an experimental autoimmune uveitis (EAU) animal model. IOX1 treated EAU mice showed less severe clinical symptoms than the solvent control treated group. Furthermore, flow cytometry analysis indicated systemic administration of IOX1 can significantly reduce intraocular pro-inflammatory T cell populations but not affect the systemic T cell counterparts. This elegant study depicted an epigenetic mechanism involving Th17 cells with a newly found molecular target of IOX1 which suppresses Il17a expression by directly targeting TET2 activity on its promoter in Th17 cells. This refined molecular mechanism can help development of epigenetic therapy for …