Mechanisms of Natural Killer cell expansion and neoplastic transformation

自然杀伤细胞扩增和肿瘤转化的机制

• 批准号: 497784080
• 负责人: Professorin Dr. Chiara Romagnani, Ph.D.
• 金额: --
• 依托单位: Institut für Medizinische Immunologie (CVK)
• 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/497784080?language=en
• 关键词: Mechanisms; Natural; Killer; cell; expansion

One of the paradigmatic feature of adaptive lymphocytes is to undergo clonal expansion upon antigen encounter. Natural Killer (NK) cells are innate lymphocytes lacking rearranged receptors that are rapidly activated in response to pathogen/danger signals or cytokines. Remarkably, infection with human cytomegalovirus (CMV) induces the expansion of a subset of peptide-specific adaptive NKG2C+ NK cells undergoing global transcriptional and epigenetic remodeling, similar to memory cells. In our preliminary data, we have performed scRNAseq, scATACseq, CITE-seq as well as analysis of mitochondrial DNA (mtDNA) mutations to track clonality within human NK cells from CMV+ and CMV- healthy donors ex vivo. This analysis revealed that, in contrast to the conventional NK cell pool, human memory NKG2C+ NK cells in CMV+ donors comprise of stable clonal expansions, displaying two major types of open chromatin domains: first, a shared signature featured by all adaptive NK cells across CMV+ donors (“public memory”); second, a diverse set of unique open chromatin regions associated with the drastic expansions of individual, stable NK cell clones (“private memory”). Based on this unexpected finding, we hypothesize that clonality and the epigenetic features associated to it might be advantageous for NK cell expansion but might put them at risk of neoplastic transformation. Interestingly, abnormal proliferations of NK cells, more recently classified as chronic lymphoproliferative disease of NK cells (CLPD-NK), comprise 15% of mature large granular lymphocytes (LGL) disorders, a spectrum of conditions ranging from lymphocytosis to overt leukemia. The pathophysiological mechanisms underlying CLPD-NK cell expansions, the degree of their clonality and epigenetic remodeling remain unclear. In this project, we will combine scRNAseq, scATACseq, CITE-seq and mtDNA mutation analysis to study NK cells from healthy CMV+ and CMV- individuals as well as from patients with diagnosed CLPD-NK with different clinical spectra in order to identify possible common epigenetic features and clonal relationships with conventional and memory NK cells from healthy donors and/or within patients. Altogether, this project will shed light on new aspects of NK cell biology, as well as into the pathophysiology of CLPD-NK disorders, and opens a perspective on the identification of new diagnostic and prognostic markers associated to disease.

适应性淋巴细胞的典型特征之一是在遇到抗原时进行克隆扩增。自然杀伤（NK）细胞是先天性淋巴细胞，缺乏重排的受体，这些受体响应于病原体/危险信号或细胞因子而被快速激活。值得注意的是，人巨细胞病毒（CMV）感染诱导肽特异性适应性NKG 2C + NK细胞亚群的扩增，这些细胞经历整体转录和表观遗传重塑，类似于记忆细胞。在我们的初步数据中，我们已经进行了scRNAseq、scATACseq、CITE-seq以及线粒体DNA（mtDNA）突变的分析，以离体追踪来自CMV+和CMV-健康供体的人NK细胞内的克隆性。该分析显示，与常规NK细胞库相比，CMV+供体中的人记忆NKG 2C + NK细胞包含稳定的克隆扩增，显示出两种主要类型的开放染色质结构域：首先，CMV+供体中所有适应性NK细胞具有的共享特征第二，与个体、稳定NK细胞克隆的急剧扩增相关的独特开放染色质区域的多样性集合（“私人记忆”）。基于这一意外的发现，我们假设克隆性和与之相关的表观遗传特征可能有利于NK细胞扩增，但可能使它们处于肿瘤转化的风险中。有趣的是，NK细胞的异常增殖，最近被分类为NK细胞的慢性淋巴细胞增殖性疾病（CLPD-NK），包括15%的成熟大颗粒淋巴细胞（LGL）疾病，从淋巴细胞增多症到明显的白血病。CLPD-NK细胞扩增的病理生理机制、克隆性和表观遗传重塑的程度仍不清楚。在本项目中，我们将结合联合收割机scRNAseq、scATACseq、CITE-seq和mtDNA突变分析来研究来自健康CMV+和CMV-个体以及来自具有不同临床谱的诊断为CLPD-NK的患者的NK细胞，以鉴定可能的共同表观遗传特征以及与来自健康供体和/或患者内的常规和记忆NK细胞的克隆关系。总而言之，该项目将揭示NK细胞生物学的新方面，以及CLPD-NK疾病的病理生理学，并开辟了识别与疾病相关的新诊断和预后标志物的前景。