Osmotic responsiveness of the master immune regulator PU.1

主免疫调节剂 PU.1 的渗透反应性

• 批准号: 8770311
• 负责人: Gregory Man Kai Poon
• 金额: $ 32.94万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8770311
• 关键词: Activated Lymphocyte; Affect; Affinity; Attention; Binding; Biological; Biological Response Modifiers; Cell Death; Cell Proliferation; Cells; Complement; Coupled; Coupling; DNA; DNA Binding; DNA Sequence; Development; Diabetes Mellitus; Discrimination; Disease; Electrostatics; Elements; Environment; Exposure to; Face; Family; Family member; Gene Expression Regulation; Gene Targeting; Genes; Genomics; Goals; Homologous Gene; Human; Hydration status; Hydrogen Bonding; Immune; Immune System Diseases; Immune response; Immune system; Immunology; Inflammation; Inflammatory; Ions; Knowledge; Lead; Lymphocyte; Lymphoid Tissue; Mediating; Molecular; Mutate; Nature; Osmolalities; Physical environment; Physiological; Play; Positioning Attribute; Proteins; Regulation; Research; Role; Site; Solutions; Specificity; Stress; Structure; T-Lymphocyte; Testing; Thermodynamics; Thymus Gland; Variant; Water; base; biological adaptation to stress; immune function; improved; in vivo; interfacial; knock-down; macrophage; member; novel; pathogen; prevent; programs; public health relevance; solute; transcription factor

DESCRIPTION (provided by applicant): Immune cells such as macrophages and activated lymphocytes are highly sensitive to osmotic stress from exposure to hyperosmotic environments (such as lymphoid tissues and local inflammation) or active cell proliferation. Cells adapt to osmotic stress by accumulating compatible osmolytes, which allow cells to efficiently retain intracellular water, maintain cytoplasmic volume, and dilute cellular ions and other critical solutes. Accumulating osmolytes significantly raise the intracellular solution osmolality, or equivalently reduce water activity. Macromolecular interactions coupled to large changes in hydration are therefore sensitive to osmotic changes inside the cell. PU.1 is an ETS-family transcription factor that regulates the development and function of immune cells such as macrophages and lymphocytes. Our recent studies have demonstrated that DNA-binding affinity and sequence selectivity for PU.1 are profoundly sensitive to their osmotic environment, but not for its close structural homolog, Ets-1. Independently, genomic studies show that regulation of PU.1-target genes, but not Ets-1 target genes, depend strongly on a functional osmotic stress response. Based on this evidence, we hypothesize that osmotic sensitivity is a mechanism for biological responsiveness and target specificity for PU.1. To test our hypothesis, we will determine the physicochemical nature of osmotic sensitivity by PU.1 and identify the structural elements that confer its osmotic sensitivity. We will use Ets-1 as an osmotically insensitive "standard" to interpret how osmotic sensitivity is specifically incorporated into PU.1, and how osmotic sensitivity affects site selectivity (the primary determinant of gene-activating potential) These proposed studies complement more than two decades of cellular and functional studies of PU.1 and other ETS transcription factors in culture and in vivo. They have specific relevance to how PU.1 and Ets-1 coordinately modulate their activities to permit correct maturation of T lymphocytes in the hyperosmotic thymus environment. Upon completion of this research, we expect to have established osmotic sensitivity as a mechanism for responsiveness by PU.1 to the cellular osmotic stress response program. More broadly, this research brings attention to hydration as a biophysical basis for responsiveness to physiologic osmotic stress in human cells. This knowledge has potential implication for our understanding of "anisotonic disorders" (such as diabetes mellitus and inflammation) associated with pathological intracellular osmotic stress.

描述（由申请人提供）：免疫细胞（例如巨噬细胞和活化的淋巴细胞）对暴露于多渗透环境（例如淋巴组织和局部炎症）或活动细胞增殖的渗透压高度敏感。细胞通过积累兼容的渗透液来适应渗透应激，从而使细胞有效保留细胞内水，保持细胞质体积，稀释细胞离子和其他关键溶质。累积的渗透压会显着提高细胞内溶液的渗透压，或同等地减少水活性。因此，与水合的大变化结合的大分子相互作用对细胞内部的渗透变化敏感。 PU.1是一种ETS家族转录因子，可调节免疫细胞（例如巨噬细胞和淋巴细胞）的发育和功能。我们最近的研究表明，PU.1的DNA结合亲和力和序列选择性对其渗透环境非常敏感，但对于其紧密的结构同源物eTET-1。独立地，基因组研究表明，PU.1靶基因的调节，而不是ETS-1靶基因，在很大程度上取决于功能性渗透应激反应。基于这些证据，我们假设渗透敏感性是PU.1的生物反应性和靶标特异性的机制。为了检验我们的假设，我们将通过pu.1确定渗透灵敏度的理化性质，并确定赋予其渗透敏感性的结构元素。我们将使用ETS-1作为渗透敏感的“标准”来解释如何将渗透敏感性专门纳入PU.1，以及渗透敏感性如何影响位点选择性（基因激活潜力的主要决定因素），这些拟议的研究补充了PU.1和其他ETS Transcription cruption in Cultrancription and vivo in Cultial and vivo的pu.1和其他ETS转录因子的细胞和功能研究超过二十年。它们与PU.1和ETS-1如何协调调节其活性以允许在高渗透性胸腺环境中正确成熟的活动有特定的相关性。这项研究完成后，我们希望建立渗透敏感性，以此作为PU.1对细胞渗透应激反应计划的反应性的机制。从更广泛的角度来看，这项研究将水合作为对人类细胞生理渗透应激的反应的生物物理基础。这些知识对我们对与病理细胞内渗透压相关的“各向异性疾病”（例如糖尿病和炎症）的理解具有潜在的影响。