Table_1_Deletion of histone demethylase Lsd1 (Kdm1a) during retinal development leads to defects in retinal function and structure.DOCX

PurposeThe purpose of this study was to investigate the role of Lysine specific demethylase 1 (Lsd1) in murine retinal development. LSD1 is a histone demethylase that can demethylate mono- and di-methyl groups on H3K4 and H3K9. Using Chx10-Cre and Rho-iCre75 driver lines, we generated novel transgenic mouse lines to delete Lsd1 in most retinal progenitor cells or specifically in rod photoreceptors. We hypothesize that Lsd1 deletion will cause global morphological and functional defects due to its importance in neuronal development.MethodsWe tested the retinal function of young adult mice by electroretinogram (ERG) and assessed retinal morphology by in vivo imaging by fundus photography and SD-OCT. Afterward, eyes were enucleated, fixed, and sectioned for subsequent hematoxylin and eosin (H&E) or immunofluorescence staining. Other eyes were plastic fixed and sectioned for electron microscopy.ResultsIn adult Chx10-Cre Lsd1fl/fl mice, we observed a marked reduction in a-, b-, and c-wave amplitudes in scotopic conditions compared to age-matched control mice. Photopic and flicker ERG waveforms were even more sharply reduced. Modest reductions in total retinal thickness and outer nuclear layer (ONL) thickness were observed in SD-OCT and H&E images. Lastly, electron microscopy revealed significantly shorter inner and outer segments and immunofluorescence showed modest reductions in specific cell type populations. We did not observe any obvious functional or morphological defects in the adult Rho-iCre75 Lsd1fl/fl animals.ConclusionLsd1 is necessary for neuronal development in the retina. Adult Chx10-Cre Lsd1fl/fl mice show impaired retinal function and morphology. These effects were fully manifested in young adults (P30), suggesting that Lsd1 affects early retinal development in mice.

本研究旨在探讨赖氨酸特异性脱甲基酶1（Lsd1）在啮齿动物视网膜发育中的作用。LSD1是一种组蛋白脱甲基酶，能够去甲基化H3K4和H3K9上的单甲基和二甲基。通过使用Chx10-Cre和Rho-iCre75驱动线路，我们创建了新的转基因小鼠品系，以在大多数视网膜祖细胞或特异性在视杆光感受器中删除Lsd1。我们假设Lsd1的删除将因其对神经元发育的重要性而导致全局的形态和功能缺陷。研究方法包括通过视网膜电图（ERG）测试成年小鼠的视网膜功能，并通过眼底摄影和光谱相干断层扫描（SD-OCT）进行体内成像来评估视网膜形态。随后，眼球被摘除、固定并切片以进行后续的苏木精和伊红（H&E）或免疫荧光染色。其他眼球经塑料固定并切片以进行电子显微镜检查。研究结果发现在成年Chx10-Cre Lsd1fl/fl小鼠中，与同龄对照小鼠相比，在暗适应条件下a、b和c波幅显著降低。在光适应和闪烁ERG波形中观察到更显著的降低。光谱相干断层扫描（SD-OCT）和H&E图像显示视网膜总厚度和外核层（ONL）厚度有轻微的减少。最后，电子显微镜揭示了内、外节显著缩短，免疫荧光显示特定细胞类型群体有轻微的减少。在成年Rho-iCre75 Lsd1fl/fl动物中，我们没有观察到明显的功能或形态缺陷。结论表明，Lsd1对于视网膜中的神经元发育是必需的。成年Chx10-Cre Lsd1fl/fl小鼠表现出视网膜功能和形态的损害。这些效应在年轻成人（P30）中得到充分体现，表明Lsd1影响小鼠的早期视网膜发育。