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）：虽然免疫系统在几乎所有器官系统中的存在被广泛认可，但很少关注免疫对内耳的影响。对人类受试者的研究表明，在一些患者中，听力损失可以用皮质类固醇成功治疗，这可能是由于其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的知识有限。由于类固醇治疗为成功治疗听力损失提供了希望，因此炎症如何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。在以前的工作中，我们已经证明，毛细胞损伤引起了一个强大的，快速招聘的专业吞噬细胞的形式单核细胞和巨噬细胞进入小鼠耳蜗。目前的研究将使用新的药理学方法和敲除小鼠品系来检查巨噬细胞在耳蜗病理和损伤恢复中的作用。在第一组实验中，我们使用脂质体包封的氯膦酸盐在体内耗尽耳蜗巨噬细胞，以确定募集的巨噬细胞在耳蜗损伤中是保护性的还是有害的。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基因缺失导致巨噬细胞进入耳蜗的增加和耳毒性损伤的增强。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。进一步的研究将检查参与的主要清道夫受体，CD36，在吞噬受损的毛细胞。我们已经表明，耳蜗巨噬细胞和耳蜗支持细胞表达CD36，这表明这两种细胞类型可能参与吞噬毛细胞碎片。我们将使用CD36基因敲除小鼠，以确定是否CD36是必不可少的识别和去除凋亡的毛细胞从Corti器官。我们还将使用辐射骨髓嵌合体来分离CD 36表达对白细胞和耳蜗支持细胞的影响。最后一个实验将检查巨噬细胞的动态作用，耳毒性的时间推移共聚焦成像的活小鼠耳蜗培养。使用这种技术，我们可以跟踪巨噬细胞的运动和活动，以确定它们如何与耳毒性损伤中的毛细胞相互作用。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和病理过程。