Natural killer cells and immune control: Deciphering the transcription factors that regulate expression of the NKG2D-ligand MICA

自然杀伤细胞和免疫控制：破译调节 NKG2D 配体 MICA 表达的转录因子

• 批准号: 324329506
• 负责人: Professorin Dr. Elke Pogge von Strandmann
• 金额: --
• 依托单位: Zentrum für Tumor- und Immunbiologie (ZTI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/324329506?language=en
• 关键词: Natural; killer; cells; immune; control

NKG2D (encoded by the KLRK1 gene, killer cell lectin-like receptor subfamily K, member 1) is a C-type lectin receptor and an important activating immunoreceptor involved in tumor surveillance. NKG2D is expressed on the surface of most cytotoxic lymphocytes such as NK cells, CD8+ T cells, some γδ T cells, and possibly also some CD4+ T cells and known as a sensor for damaged or dangerous cells. Ligands for NKG2D (NKG2D-L) are generally not expressed on healthy cells but are induced on the surface of malignant cells. Evasion from the innate NKG2D-mediated immune surveillance is a hallmark of many solid and hematopoietic tumors and depends among other strategies on proteolytic shedding and release of soluble NKG2D-L. This renders target cells invisible to an NKG2D-dependent NK cell attack and moreover causes a downregulation of receptor surface expression on effector cells. Targeting the NKG2D-NKG2D-L axis to stimulate anti-tumor immunity is a promising therapeutic approach. Here, we aim to identify specific transcription factors, which regulate the inducible expression of MHC Class I Polypeptide-Related Sequence A (NKG2D-L, MICA). Until today the network of transcription factors regulating the up-regulation of MICA is not defined. A better understanding of factors that direct NKG2D-L expression will contribute to the development of novel therapeutic strategies aiming at an increased NKG2D-L expression on the tumor cell surface and thus more efficient killing by NK cells. In our previous work, we demonstrated that CBP/p300 acetyltransferases and the cAMP responsive element binding protein (CREB) contribute critically to the inducible expression of MICA. Using an enChIP approach we identified several transcription factors which are in response to histone deacetylase inhibition associated with the active MICA promoter including Krüppel-like factor 4 (KLF4), Yin Yang 1 (YY1), and CCCTC-Binding Factor (CTCF). The aim of this project is to assess the involvement of these candidate proteins, in particular transcription factors, in the regulation of MICA expression. For this purpose, we plan to analyze to what extend these factors regulate the transcription of MICA in promoter-reporter assays. Further overexpression and depletion approaches are planned to investigate the impact on MICA surface protein expression and on NK cell-mediated target cell elimination. Finally the clinical relevance of the identified factors will be assessed in acute myeloma leukemia patient samples. To this end we will perform Rhapsodytm (Beckman Coulter) single-cell sequencing to correlate MICA and candidate factor expression and to measure whether these factors regulate (gain/loss of function) MICA expression and susceptibility against NK cells. We expect that we will identify positive regulators of MICA which may on the long run represent novel therapeutic targets.

NKG 2D（由KLRK 1基因编码，杀伤细胞凝集素样受体亚家族K，成员1）是一种C型凝集素受体，也是一种参与肿瘤监视的重要活化免疫受体。NKG 2D在大多数细胞毒性淋巴细胞（如NK细胞、CD 8 + T细胞、一些γδ T细胞，也可能是一些CD 4 + T细胞）的表面上表达，被称为受损或危险细胞的传感器。NKG 2D（NKG 2D-L）的配体通常不在健康细胞上表达，但在恶性细胞表面上被诱导。逃避先天NKG 2D介导的免疫监视是许多实体瘤和造血系统肿瘤的标志，并且在其他策略中取决于可溶性NKG 2D-L的蛋白水解脱落和释放。这使得靶细胞对NKG 2D依赖性NK细胞攻击不可见，此外还导致效应细胞上受体表面表达下调。靶向NKG 2D-NKG 2D-L轴以刺激抗肿瘤免疫是一种有前景的治疗方法。 在这里，我们的目标是确定特定的转录因子，调节诱导型表达的MHC I类多肽相关序列A（NKG 2D-L，云母）。直到今天，调控云母上调的转录因子网络尚未确定。更好地了解指导NKG 2D-L表达的因素将有助于开发新的治疗策略，旨在增加肿瘤细胞表面上的NKG 2D-L表达，从而提高NK细胞的杀伤效率。 在我们以前的工作中，我们证明了CBP/p300乙酰转移酶和cAMP反应元件结合蛋白（CREB）对云母的诱导型表达有重要贡献。使用enChIP方法，我们鉴定了几种转录因子，其响应于与活性云母启动子相关的组蛋白脱乙酰酶抑制，包括Krüppel样因子4（KLF 4）、阴阳1（YY 1）和CCCTC结合因子（CTCF）。 该项目的目的是评估这些候选蛋白质，特别是转录因子，在云母表达的调节中的参与。为了这个目的，我们计划在启动子-报告基因分析中分析这些因子在多大程度上调节云母的转录。计划进一步的过表达和耗竭方法来研究对云母表面蛋白表达和NK细胞介导的靶细胞消除的影响。最后，将在急性骨髓瘤白血病患者样本中评估所鉴定因素的临床相关性。为此，我们将进行Rhapsodytm（Beckman Coulter）单细胞测序，以关联云母和候选因子表达，并测量这些因子是否调节（功能获得/丧失）云母表达和对NK细胞的易感性。 我们希望我们将确定积极的监管机构的云母可能在长期代表新的治疗目标。