title: Dynamic activation of basilar membrane macrophages in response to chronic sensory cell degeneration in aging mouse cochleae.
abstract: In the sensory epithelium, macrophages have been identified on the scala tympani side of the basilar membrane. These basilar membrane macrophages are the spatially closest immune cells to sensory cells and are able to directly respond to and influence sensory cell pathogenesis. While basilar membrane macrophages have been studied in acute cochlear stresses, their behavior in response to chronic sensory cell degeneration is largely unknown. Here we report a systematic observation of the variance in phenotypes, the changes in morphology and distribution of basilar membrane tissue macrophages in different age groups of C57BL/6J mice, a mouse model of age-related sensory cell degeneration. This study reveals that mature, fully differentiated tissue macrophages, not recently infiltrated monocytes, are the major macrophage population for immune responses to chronic sensory cell death. These macrophages display dynamic changes in their numbers and morphologies as age increases, and the changes are related to the phases of sensory cell degeneration. Notably, macrophage activation precedes sensory cell pathogenesis, and strong macrophage activity is maintained until sensory cell degradation is complete. Collectively, these findings suggest that mature tissue macrophages on the basilar membrane are a dynamic group of cells that are capable of vigorous adaptation to changes in the local sensory epithelium environment influenced by sensory cell status.
authors.affiliation: Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA. Electronic address: mfrye@buffalo.edu.
authors.forename: Mitchell D
authors.initials: MD
authors.lastname: Frye
authors.affiliation: Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA. Electronic address: yangwp301@126.com.
authors.forename: Weiping
authors.initials: W
authors.lastname: Yang
authors.affiliation: Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA. Electronic address: celiazha@buffalo.edu.
authors.forename: Celia
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA. Electronic address: xiongbb2015@126.com.
authors.forename: Binbin
authors.initials: B
authors.lastname: Xiong
authors.affiliation: Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA. Electronic address: bhu@buffalo.edu.
authors.forename: Bo Hua
authors.initials: BH
authors.lastname: Hu
mesh_terms: D000161:Acoustic Stimulation; D000367:Age Factors; D000375:Aging / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D001309:Auditory Threshold; D001489:Basilar Membrane / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D015415:Biomarkers / Q000378:metabolism; D003051:Cochlea / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D006198:Hair Cells, Auditory / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008810:Mice, Inbred C57BL; D009410:Nerve Degeneration
chemical_list: D015415:Biomarkers
keywords: Aging; C57BL/6J; Cochlea; Hair cells; Immunity; Macrophage