Apicosome: Newly identified cell-type-specific organelle in mouse cochlear and vestibular hair cells
Xiaofen Li,
Qirui Zhao,
Xiaojie Yu,
Wenhan Cao,
Yingyi Zhang,
Wanying Feng,
Liwen Jiang,
David Z. He,
Robert Z. Qi,
Pingbo Huang
Affiliations
Xiaofen Li
Division of Life Science, Hong Kong University of Science and Technology, Hong Kong 999077, China; Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China; Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
Qirui Zhao
Division of Life Science, Hong Kong University of Science and Technology, Hong Kong 999077, China
Xiaojie Yu
Division of Life Science, Hong Kong University of Science and Technology, Hong Kong 999077, China
Wenhan Cao
School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China; State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; Provincial Key Laboratory of Forest Aromatic Plants-based Healthcare Functions, Zhejiang A & F University, Hangzhou 311300, China
Yingyi Zhang
Biological Cryo-EM Center, Hong Kong University of Science and Technology, Hong Kong 999077, China; Office of the Vice-President for Research and Development, Hong Kong University of Science and Technology, Hong Kong 999077, China
Wanying Feng
Division of Life Science, Hong Kong University of Science and Technology, Hong Kong 999077, China
Liwen Jiang
School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China
David Z. He
Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE 68178, USA
Robert Z. Qi
Division of Life Science, Hong Kong University of Science and Technology, Hong Kong 999077, China; Bioscience and Biomedical Engineering Thrust, Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511453, China
Pingbo Huang
Division of Life Science, Hong Kong University of Science and Technology, Hong Kong 999077, China; Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong 999077, China; State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong 999077, China; HKUST Shenzhen Research Institute, Hong Kong University of Science and Technology, Hong Kong 999077, China; Hong Kong Branch of Guangdong Southern Marine Science and Engineering Laboratory (Guangzhou), Hong Kong University of Science and Technology, Hong Kong 999077, China; Corresponding author
Summary: Cochlear and vestibular hair cells are highly specialized sensory receptors for hearing and balance. Here, we report a serendipitous identification of a hair-cell-specific organelle in neonatal mouse inner ear, which we name “apicosome.” The apicosome is ∼500 nm in diameter and shows itinerant nature and transient appearance during development in cochlear hair cells. In contrast to cochlear hair cells, the apicosome persists in vestibular hair cells even in adult. The timing of apicosome translocation and disappearance in cochlear hair cells during development is correlated with kinocilium development and maintenance. The apicosome is not seen in supporting cells despite the fact that nascent supporting cells have microvilli and a primary cilium. Interestingly, transdifferentiated hair cells from supporting cells also contain apicosome, suggesting that it is unique to hair cells. Thus, our study identifies a previously undescribed organelle in hair cells and lays the foundation for further characterization of this specialized structure.
