Molecular Mechanisms Controlling NK Receptors

描述（由申请人提供）：自然杀伤（NK）细胞杀死感染和恶性细胞，并指导随后的适应性免疫。NK细胞主要通过杀伤细胞免疫球蛋白样受体（KIR）来区分正常细胞和异常细胞。尽管KIR基因之间具有高度的同源性，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相反，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方法。为了实现这一目标，下一步是进一步研究KIR在淋巴瘤和骨髓增生异常综合征的正常生理和表观遗传治疗中的表达控制。提出这项研究的基本原理是，一旦更好地了解了KIR基因的调控，那么就可以操纵KIR的表达来制造有效的NK细胞试剂，用于癌症和传染病的免疫治疗。在这项提议中，2DL4和crKIR启动子将被研究，特别关注克服DNA甲基化和抑制染色质的机制。由于对淋巴细胞特异性基因表达如何受到癌症和表观遗传治疗的影响知之甚少，我们将研究DNA甲基化和组蛋白去乙酰化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细胞活化。这项工作可能解释了为什么NK功能在癌症患者中很差，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表达及其靶mrna进行分类，并研究microRNA调节“危险”细胞毒性NK细胞和“未经许可”抑制受体阴性NK细胞的机制。这将为今后研究NK在健康和疾病中的发育决定的控制提供必要的基础信息。本研究将1)清楚地了解控制KIR表达起始和维持的多层调控；2)首次建立了表观遗传治疗在体内对非恶性人淋巴细胞基因表达和功能的影响；3)揭示NK特异性microRNA模式，并阐明它们如何控制mRNA靶点来调节NK发育和设置NK细胞激活阈值。这些结果将非常重要，因为它们对于理解NK细胞如何区分正常细胞和异常细胞至关重要。这样的认识将为操纵NK细胞治疗癌症和传染病提供新的方法。公共卫生相关性：自然杀伤（NK）细胞杀死感染和恶性细胞，并指导随后的适应性免疫。长期目标是利用NK细胞作为癌症和传染病的有效治疗方法。为了实现这一目标，下一步的目标是进一步研究NK基因在正常生理和癌症及癌症前期（如淋巴瘤和骨髓增生异常综合征）中的表达控制。

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.