Molecular Mechanisms Controlling NK Receptors

描述(申请人提供)：自然杀伤(NK)细胞杀死感染和恶性细胞，并直接随后的适应性免疫。NK细胞主要通过杀伤细胞免疫球蛋白样受体(KIR)区分正常和异常细胞。尽管KIR基因之间有很高的同源性，但单个NK细胞表达不同数量和组合的克隆限制性KIR(CrKIR)基因。与crKIR不同，KIR2DL4在所有NK细胞中表达，在NK发育过程中先于crKIR表达。长期目标是利用NK细胞作为癌症和传染病的有效治疗手段。作为实现这一目标的下一个合乎逻辑的步骤，目前的目标是进一步表征KIR在正常生理和淋巴瘤和骨髓增生异常综合征的表观遗传治疗期间的表达控制。这项研究的基本原理是，一旦更好地了解了KIR基因的调控，就可以操纵KIR的表达，使其成为有效的NK细胞试剂，用于癌症和传染病的免疫治疗。在这项提案中，将研究2DL4和crKIR启动子，特别关注克服DNA甲基化和抑制染色质的机制。由于对肿瘤和表观遗传治疗对淋巴细胞特异性基因表达的影响知之甚少，我们将研究DNA甲基化和组蛋白去乙酰酶抑制剂药物如何影响骨髓增生异常综合征和淋巴瘤患者的KIR启动子甲基化、KIR表达和NK细胞激活。这项工作可能解释为什么癌症患者的NK功能很差，并可能提出提高这些患者免疫力的策略。我们将对NK细胞microRNA的表达和它们的靶mRNAs进行分类，并将研究microRNA调节“危险的”细胞毒性NK细胞和“未经许可的”抑制性受体阴性的NK细胞的机制。这将为未来控制NK在健康和疾病中的发育决策提供所需的基本信息。这项研究将1)清楚地了解控制KIR表达启动和维持的多层调控；2)首次建立表观遗传治疗如何影响体内非恶性人类淋巴细胞基因的表达和功能；3)揭示NK特异的microRNA模式，并阐明它们如何控制mRNA靶标来调节NK的发育和设定NK细胞的激活阈值。这些结果将具有非常重要的意义，因为它们将是理解NK细胞如何区分正常和异常细胞的关键。这样的理解将为在癌症和传染病治疗中操纵NK细胞提供新的方法。公共卫生相关性：自然杀伤(NK)细胞杀死感染细胞和恶性细胞，并直接随后的适应性免疫。长期目标是利用NK细胞作为癌症和传染病的有效治疗手段。作为实现这一目标的下一个合乎逻辑的步骤，目前的目标是进一步确定正常生理以及癌症和癌前病变(如淋巴瘤和骨髓增生异常综合征)中NK基因表达控制的特征。

DESCRIPTION (provided by applicant): Natural killer (NK) cells kill infected and malignant cells and direct subsequent adaptive immunity. NK cells distinguish normal from aberrant cells largely via killer cell immunoglobulin-like receptors (KIR). Despite high homology between KIR genes, individual NK cells express distinct numbers and combinations of clonally-restricted KIR (crKIR) genes. In contrast to crKIR, KIR2DL4 is expressed by all NK cells, preceding crKIR expression during NK development. The long-range goal is to use NK cells as effective treatments of cancer and infectious diseases. As the next logical step toward that goal, the current objectives are to further characterize KIR expression control in normal physiology and during epigenetic therapy of lymphoma and myelodysplastic syndrome. The rationale for the proposed research is that once KIR gene regulation is better understood, then KIR expression can be manipulated to make effective NK cells reagents in immunotherapy of cancer and infectious diseases. In this proposal, 2DL4 and crKIR promoters will be investigated, with special attention to mechanisms that overcome DNA methylation and repressive chromatin. Because so little is known about how lymphocyte-specific gene expression is influenced by cancer and by epigenetic therapy, we will study how DNA methylation and histone deacetylase inhibitor drugs affect KIR promoter methylation, KIR expression, and NK cell activation in myelodysplastic syndrome and lymphoma patients. This work may explain why NK function is poor in cancer patients and might suggest strategies for boosting immunity in these patients. We will catalog NK cell microRNA expression and their target mRNAs and we will investigate the microRNA mechanisms that regulate "dangerous" cytotoxic NK cells and "unlicensed" inhibitory receptor- negative NK cells. This will provide the basic information needed for future studies on control of NK developmental decisions in health and disease. This study will 1) develop a clear understanding of the multiple layers of regulation that control the initiation and maintenance of KIR expression; 2) establish for the first time how epigenetic therapy affects nonmalignant human lymphocyte gene expression and function in vivo; and 3) reveal NK-specific microRNA patterns and elucidate how they control mRNA targets to regulate NK development and set NK cell activation thresholds. These results will be highly significant, because they will be essential for understanding how NK cells distinguish normal from aberrant cells. Such an understanding will suggest new ways to manipulate NK cells in the therapy of cancer and infectious diseases. PUBLIC HEALTH RELEVANCE: Natural killer (NK) cells kill infected and malignant cells and direct subsequent adaptive immunity. The long-range goal is to use NK cells as effective treatments of cancer and infectious diseases. As the next logical step toward that goal, the current objectives are to further characterize NK gene expression control in normal physiology and in cancers and pre-cancers, such as lymphoma and myelodysplastic syndrome.