Sienknecht Ulrike J
Department of Neuroscience, School of Medicine and Health Science, Research Center Neurosensory Science, Cluster of Excellence "Hearing4all", Carl von Ossietzky University Oldenburg, Carl von Ossietzky Strasse 9-11, 26129, Oldenburg, Germany,
Cell Tissue Res. 2015 Jul;361(1):25-32. doi: 10.1007/s00441-015-2200-1. Epub 2015 May 12.
Phylogenetically and ontogenetically, vertebrate development led to the generation of several inner ear sensory organs. During embryogenesis, cell fate specification determines whether each progenitor cell differentiates into a sensory hair cell or a supporting cell within the common sensory primordium. Finally, all sensory epithelia of the inner ear consist of a hair cell/supporting cell mosaic, albeit with anatomical differences depending on the sensory organ type. Hair cells develop a polarized bundle of stereovilli that is of functional importance for mechanotransduction. After initiating stereovillar development, hair cells align their bundles in a coordinated fashion, generating a characteristic hair cell orientation pattern, a process referred to as planar cell polarity (PCP). The pathway that controls PCP in the inner ear needs both to establish the development of a polarized morphology of the stereovillar bundle of the hair cell and to organize a systematic hair cell alignment. Because the hair cell orientation patterns of the various inner ear organs and vertebrate species differ fundamentally, it becomes apparent that in vertebrates, different aspects of PCP need to be independently controlled. In spite of important progress recently gained in the field of PCP research, we still need to identify the mechanisms (1) that initiate molecular asymmetries in cells, (2) that guide the transmission of polarity information from cell to cell, and (3) that consistently translate such polarity information into morphological asymmetries of hair cells.
从系统发育和个体发育角度来看，脊椎动物的发育导致了几个内耳感觉器官的产生。在胚胎发生过程中，细胞命运特化决定了每个祖细胞在共同的感觉原基内是否分化为感觉毛细胞或支持细胞。最后，内耳的所有感觉上皮都由毛细胞/支持细胞镶嵌而成，尽管根据感觉器官类型存在解剖学差异。毛细胞发育出一束极化的静纤毛，这对机械转导具有重要功能。在启动静纤毛发育后，毛细胞以协调的方式排列它们的束，产生特征性的毛细胞定向模式，这个过程称为平面细胞极性（PCP）。控制内耳中PCP的途径既需要建立毛细胞静纤毛束极化形态的发育，又需要组织系统的毛细胞排列。由于各种内耳器官和脊椎动物物种的毛细胞定向模式存在根本差异，因此很明显，在脊椎动物中，PCP的不同方面需要独立控制。尽管最近在PCP研究领域取得了重要进展，但我们仍然需要确定以下机制：（1）在细胞中启动分子不对称性的机制；（2）指导极性信息在细胞间传递的机制；（3）将这种极性信息持续转化为毛细胞形态不对称性现实的机制。
