Membrane potential and Calcium Signaling in Neutrophil Development and Inflammation

中性粒细胞发育和炎症中的膜电位和钙信号传导

• 批准号: 10529325
• 负责人: Regina Clemens
• 金额: $ 39.21万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-19 至 2026-10-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10529325
• 关键词: Acute; Acute Lung Injury; Bacteria; Bacterial Infections; Biological; Biology; Calcium; Calcium Channel; Calcium Signaling; Calcium ion; Calcium-Activated Potassium Channel; Cell membrane; Cell physiology; Cells; Charge; Clinical; Communicable Diseases; Coupling; Cytoplasmic Granules; Cytotoxin; Data; Development; Disease; Emergency Situation; Enzymes; Event; Functional disorder; Genetic; Goals; Gout; Granulopoiesis; Hemolysin; Host Defense; Human; Immune; Infection; Inflammation; Inflammatory; Innate Immune System; Ion Channel; Knowledge; Laboratories; Lymphocyte; Mediating; Mediator; Membrane Potentials; Molecular; Mus; Mycoses; Neutropenia; Neutrophil Activation; Pathogenesis; Pathway interactions; Patients; Predisposition; Process; Reactive Oxygen Species; Regulation; Rheumatoid Arthritis; Role; Sepsis; Signal Pathway; Signal Transduction; Staphylococcus aureus; Stimulus; Testing; Therapeutic Intervention; Tissues; Toxic Neutrophil; Toxin; Virulence; chronic inflammatory disease; driving force; extracellular; first responder; immune system function; insight; mast cell; mouse model; neutrophil; pathogen; pathogenic bacteria; response

PROJECT SUMMARY Neutrophils are essential for host defense against bacteria, however toxic neutrophil mediators such as reactive oxygen radicals, granule enzymes and neutrophil extracellular traps contribute the pathogenesis of acute and chronic inflammatory diseases. While the ability of neutrophils to phagocytose and kill pathogens has been known for over 100 years, our knowledge of the molecular mechanisms guiding neutrophil activation lags significantly behind that of other immune cells, precluding the development of strategic therapeutic interventions targeting neutrophils. Our long-term goal is to define the mechanisms by which ion channels and associated signaling pathways regulate neutrophil activation, and to leverage this knowledge to modify disease. Calcium signals initiated via store-operated calcium entry (SOCE) are required for neutrophil activation. The cell membrane potential directly influences influx of positively charged calcium ions. While the functional role of the cell membrane potential has been extensively studied in excitable cells, little is known about how the membrane potential modifies cellular processes in neutrophils in the context of development and inflammation. This proposal is based on four fundamental observations from our laboratory: 1) ORAI1 and ORAI2 calcium channels are critical for neutrophil SOCE and host defense during infection with S. aureus. 2) Calcium responses in mouse neutrophils are heterogenous, with the magnitude of the calcium response modulated in part by differential regulation of the cell membrane potential. 3) Expression of the calcium- activated potassium channel KCa3.1 (Kcnn4) drives cell hyperpolarization and enhanced SOCE in a subset of neutrophils. 4) The membrane potential-SOCE relationship is modulated during neutrophil development and emergency granulopoiesis. Moreover, we have observed that a S. aureus pore-forming toxin manipulates the neutrophil membrane potential and SOCE. Together these observations illustrate that the membrane potential is a key modifier of calcium-dependent neutrophil function, and suggest that this pathway is a strategic target of human pathogenic bacteria that secrete pore-forming cytotoxins to overcome host neutrophil defenses. The objective of this proposal is to characterize the mechanisms by which membrane potential regulates SOCE during neutrophil development and inflammation. We will test the central hypothesis that the membrane potential is a critical modifier of neutrophil calcium signaling in mature neutrophils and homeostatic and emergency granulopoiesis. In Aims 1 and 2 we will investigate the role of KCa3.1 in neutrophil SOCE and calcium-dependent activation in mature and developing neutrophils. In Aim 3 we will expand these studies to investigate how exogenous manipulation of the cell membrane potential by bacterial pore-forming toxins disrupts calcium-dependent neutrophil function. The insight derived from these studies is anticipated to engender new clinical opportunities for modulation of neutrophil-dependent infectious and inflammatory disease, and potentially inform a broader understanding of membrane potential in immune cell function.

项目总结