COCHLEAR MACROPHAGES AND EPITHELIAL REPAIR

耳蜗巨噬细胞和上皮修复

• 批准号: 8579801
• 负责人: Keiko Hirose
• 金额: $ 38万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-15 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8579801
• 关键词: Acoustics; Adrenal Cortex Hormones; Affect; Aminoglycoside Antibiotics; Anatomy; Anti-Inflammatory Agents; Anti-inflammatory; Apoptosis; Apoptotic; Area; Attention; Bacteria; Binding; Birds; Blood Vessels; Bone Marrow; CD36 gene; CX3CL1 gene; Cell Death Process; Cell Maintenance; Cells; Chimera organism; Cochlea; Complex; Confocal Microscopy; Cues; Dichloromethylene Diphosphonate; Ear; Encapsulated; Epithelial; Epithelium; Event; Excision; Exposure to; Family; Genetic; Goals; Hair Cells; Hearing; Image; Immune system; Immunity; Immunosuppression; Infectious Agent; Inflammation; Inflammatory; Injury; Knockout Mice; Knowledge; Labyrinth; Lateral; Leukocytes; Life; Ligands; Light; Liposomes; Maintenance; Mediating; Methods; Mononuclear; Mouse Strains; Movement; Mus; Natural regeneration; Organ Culture Techniques; Organ of Corti; Pathologic Processes; Pathology; Patients; Pattern recognition receptor; Phagocytes; Phagocytosis; Pharmaceutical Preparations; Plant Roots; Play; Predisposition; Preparation; Process; Protein Tyrosine Kinase; Proteins; Radiation; Recovery; Recruitment Activity; Research; Role; Sensory; Signal Transduction; Signaling Molecule; Source; Speed; Staging; Stereotyping; Steroid therapy; Supporting Cell; Surface; Techniques; Time; Transmission Electron Microscopy; Virus; Work; body system; cell injury; cell type; chemokine receptor; cytokine; hearing impairment; human subject; improved; in vivo; injured; inner ear injury; macrophage; member; monocyte; novel; ototoxicity; pathogen; public health relevance; receptor; repaired; research study; scavenger receptor; time use

DESCRIPTION (provided by applicant): While the presence of the immune system in virtually all organ systems is widely recognized, little attention has been paid to the influences of immunity on the inner ear. Research in human subjects demonstrates that hearing loss is successfully treated with corticosteroids in some patients, presumably due to their anti-inflammatory and immunosuppressive effects. Unfortunately, we possess limited knowledge of the cellular mechanisms that influence interactions between inflammatory processes and normal function of the inner ear. Because steroid therapy provides such hope for successful treatment of hearing loss, the specific mechanisms of how inflammation affects hearing warrant further study. The long-term goal of our research is to identify the role of inflammation in cochlear maintenance and injury. In prior work, we have demonstrated that hair cell injury evokes a strong, rapid recruitment of professional phagocytes in the form of monocytes and macrophages into the mouse cochlea. The present studies will use novel pharmacological methods and knockout mouse strains to examine the role of macrophages in cochlear pathology and recovery from injury. In the first set of experiments, we use liposomally-encapsulated clodronate to deplete cochlear macrophages in vivo, in order to determine whether recruited macrophages are protective or detrimental in cochlear injury. Next, we will examine the role of the chemokine receptor CX3CR1, expressed in cochlear monocytes and macrophages, in ototoxic injury. Our studies have shown that genetic deletion of CX3CR1 leads to both increased macrophage entry into the cochlea and enhancement of ototoxic injury. Proposed experiments will determine whether suppressing macrophages in CX3CR1-knockout mice can reverse this effect. Additional studies will examine the involvement of the cardinal scavenger receptor, CD36, in the phagocytosis of injured hair cells. We have shown that CD36 is expressed by both cochlear macrophages and cochlear supporting cells, suggesting that both cell types may be involved in phagocytosis of hair cell debris. We will use CD36 knockout mice to determine whether CD36 is essential for the recognition and removal of apoptotic hair cells from the organ of Corti. We will also use radiation bone marrow chimeras to isolate the effects of CD36 expression on leukocytes versus cochlear supporting cells. A final experiment will examine the dynamic role of macrophages in ototoxicity by time lapse confocal imaging of the live mouse cochlea in culture. Using this technique, we can follow the movement and activity of macrophages to determine how they interact with hair cells in ototoxic injury. These experiments will broadly study the role of leukocytes in the inner ear after hair cell injury and will allow us to begin understanding how immunosuppression affects normal processes as well as pathological processes in the inner ear.

描述（由申请人提供）：虽然人们广泛认识到几乎所有器官系统中都存在免疫系统，但很少有人关注免疫对内耳的影响。对人体的研究表明，皮质类固醇可以成功治疗一些患者的听力损失，这可能是由于皮质类固醇的抗炎和免疫抑制作用。不幸的是，我们对影响炎症过程和内耳正常功能之间相互作用的细胞机制了解有限。由于类固醇疗法为成功治疗听力损失提供了希望，因此炎症影响听力的具体机制值得进一步研究。我们研究的长期目标是确定炎症在耳蜗维护和损伤中的作用。在之前的工作中，我们已经证明，毛细胞损伤会引起单核细胞和巨噬细胞形式的专业吞噬细胞强烈、快速地募集到小鼠耳蜗中。目前的研究将使用新的药理学方法和基因敲除小鼠品系来研究巨噬细胞在耳蜗病理学和损伤恢复中的作用。在第一组实验中，我们使用脂质体封装的氯膦酸盐在体内消耗耳蜗巨噬细胞，以确定招募的巨噬细胞在耳蜗损伤中是否具有保护性或有害性。接下来，我们将研究在耳蜗单核细胞和巨噬细胞中表达的趋化因子受体 CX3CR1 在耳毒性损伤中的作用。我们的研究表明，CX3CR1 的基因缺失会导致巨噬细胞进入耳蜗的数量增加，并增强耳毒性损伤。拟议的实验将确定抑制 CX3CR1 敲除小鼠中的巨噬细胞是否可以逆转这种效应。其他研究将检查主要清道夫受体 CD36 在吞噬受损毛细胞中的作用。我们已经证明 CD36 由耳蜗巨噬细胞和耳蜗支持细胞表达，表明这两种细胞类型可能都参与毛细胞碎片的吞噬作用。我们将使用 CD36 敲除小鼠来确定 CD36 是否对于识别和去除 Corti 器官中凋亡的毛细胞至关重要。我们还将使用放射骨髓嵌合体来分离 CD36 表达对白细胞与耳蜗支持细胞的影响。最后的实验将通过对培养的活小鼠耳蜗进行延时共聚焦成像来检查巨噬细胞在耳毒性中的动态作用。使用这种技术，我们可以跟踪巨噬细胞的运动和活动，以确定它们在耳毒性损伤中如何与毛细胞相互作用。这些实验将广泛研究毛细胞损伤后白细胞在内耳中的作用，并使我们能够开始了解免疫抑制如何影响内耳的正常过程以及病理过程。