title: Distorted Coarse Axon Targeting and Reduced Dendrite Connectivity Underlie Dysosmia after Olfactory Axon Injury.
abstract: The glomerular map in the olfactory bulb (OB) is the basis for odor recognition. Once established during development, the glomerular map is stably maintained throughout the life of an animal despite the continuous turnover of olfactory sensory neurons (OSNs). However, traumatic damage to OSN axons in the adult often leads to dysosmia, a qualitative and quantitative change in olfaction in humans. A mouse model of dysosmia has previously indicated that there is an altered glomerular map in the OB after the OSN axon injury; however, the underlying mechanisms that cause the map distortion remain unknown. In this study, we examined how the glomerular map is disturbed and how the odor information processing in the OB is affected in the dysosmia model mice. We found that the anterior-posterior coarse targeting of OSN axons is disrupted after OSN axon injury, while the local axon sorting mechanisms remained. We also found that the connectivity of mitral/tufted cell dendrites is reduced after injury, leading to attenuated odor responses in mitral/tufted cells. These results suggest that existing OSN axons are an essential scaffold for maintaining the integrity of the olfactory circuit, both OSN axons and mitral/tufted cell dendrites, in the adult.
authors: Laboratory for Sensory Circuit Formation, RIKEN Center for Developmental Biology, Chuo-ku 650-0047, Japan; Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan.
authors: Aya
authors: 0000-0001-6322-5459
authors: A
authors: Murai
authors: Laboratory for Sensory Circuit Formation, RIKEN Center for Developmental Biology , Chuo-ku 650-0047, Japan.
authors: Ryo
authors: R
authors: Iwata
authors: Laboratory for Sensory Circuit Formation, RIKEN Center for Developmental Biology , Chuo-ku 650-0047, Japan.
authors: Satoshi
authors: S
authors: Fujimoto
authors: Laboratory for Sensory Circuit Formation, RIKEN Center for Developmental Biology , Chuo-ku 650-0047, Japan.
authors: Shuhei
authors: S
authors: Aihara
authors: Laboratory for Molecular Biology of Neural System, Advanced Medical Research Center, Nara Medical University School of Medicine , Kashihara 634-8521, Nara, Japan.
authors: Akio
authors: 0000-0002-4790-4512
authors: A
authors: Tsuboi
authors: Department of Developmental Biology, Graduate School of Medicine, Chiba University , Chiba 260-8670, Japan.
authors: Yuko
authors: 0000-0002-6697-2123
authors: Y
authors: Muroyama
authors: Department of Developmental Biology, Graduate School of Medicine, Chiba University , Chiba 260-8670, Japan.
authors: Tetsuichiro
authors: 0000-0002-1538-1454
authors: T
authors: Saito
authors: Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , Okayama 700-8558, Japan.
authors: Kazunori
authors: 0000-0002-3895-7858
authors: K
authors: Nishizaki
authors: Laboratory for Sensory Circuit Formation, RIKEN Center for Developmental Biology, Chuo-ku 650-0047, Japan; Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan.
authors: Takeshi
authors: 0000-0002-8449-0080
authors: T
authors: Imai
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism / Q000473:pathology*; D003712:Dendrites / Q000378:metabolism / Q000473:pathology*; D005260:Female; D008297:Male; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D000857:Olfaction Disorders / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D009830:Olfactory Bulb / Q000378:metabolism / Q000473:pathology*; D018034:Olfactory Receptor Neurons / Q000378:metabolism / Q000473:pathology*; D012903:Smell / Q000502:physiology
keywords: dysosmia; glomerular map; olfactory bulb; olfactory sensory neurons; regeneration; traumatic axon injury