Quantitative and Qualitative Evaluation of Photoreceptor Synapses in Developing, Degenerating and Regenerating Retinas
Quantitative and Qualitative Evaluation of Photoreceptor Synapses in Developing, Degenerating and Regenerating Retinas
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DOI：
10.3389/fncel.2019.00016
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发表时间：
2019-02-11
影响因子：
5.3
通讯作者：
Mandai, Michiko
中科院分区：
文献类型：
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作者：
Akiba, Ryutaro;Matsuyama, Take;Mandai, Michiko
突触的定量和定性评价对于理解神经连接至关重要。鉴于再生生物学和医学的最新进展，这一点现在尤其重要。因此，迫切需要对突触进行评估，以评估重建神经网络的范围和功能。目前使用的大多数突触评估方法只提供全或无评估。然而，突触经常出现在广泛的瞬态谱中，例如在突触发生或神经变性期间。因此，对突触数量和质量的鲁棒评估是非常受欢迎的。在本文中，我们介绍了QUANTOS，一种新的方法，可以评估的数量，可能性和成熟的感光带突触的免疫组织化学图像的图形特性的基础上。QUANTOS由ImageJ Fiji宏和R脚本组成，它们都是开源和免费软件。我们使用QUANTOS评估发育和退化视网膜中的突触发生，以及移植到视网膜退化小鼠模型后小鼠iPSC视网膜的从头突触发生。我们的分析表明，虽然小鼠iPSC视网膜在体外基本上不能形成突触，但它们可以在移植后形成广泛的突触。与野生型视网膜相比，移植后检测到的新生突触似乎处于成熟和不成熟之间的中间状态。此外，使用QUANTOS，我们测试了环境光是否会影响感光细胞突触发生。我们发现，突触发生的启动周期光（LD）条件下相比，恒定黑暗（DD）时，导致更多的突触在早期发育阶段。微视网膜电图也支持光的影响，在LD条件下显示更大的响应。在LD条件下将小鼠iPSC-视网膜移植到rd 1小鼠后，突触的数量也增加。我们对突触的新概率评估可能被证明是一种有价值的工具，可以获得对神经网络重建的重要见解，并帮助开发神经退行性疾病的治疗方法。
Quantitative and qualitative evaluation of synapses is crucial to understand neural connectivity. This is particularly relevant now, in view of the recent advances in regenerative biology and medicine. There is an urgent need to evaluate synapses to access the extent and functionality of reconstructed neural network. Most of the currently used synapse evaluation methods provide only all-or-none assessments. However, very often synapses appear in a wide spectrum of transient states such as during synaptogenesis or neural degeneration. Robust evaluation of synapse quantity and quality is therefore highly sought after. In this paper we introduce QUANTOS, a new method that can evaluate the number, likelihood, and maturity of photoreceptor ribbon synapses based on graphical properties of immunohistochemistry images. QUANTOS is composed of ImageJ Fiji macros, and R scripts which are both open-source and free software. We used QUANTOS to evaluate synaptogenesis in developing and degenerating retinas, as well as de novo synaptogenesis of mouse iPSC-retinas after transplantation to a retinal degeneration mouse model. Our analysis shows that while mouse iPSC-retinas are largely incapable of forming synapses in vitro, they can form extensive synapses following transplantation. The de novo synapses detected after transplantation seem to be in an intermediate state between mature and immature compared to wildtype retina. Furthermore, using QUANTOS we tested whether environmental light can affect photoreceptor synaptogenesis. We found that the onset of synaptogenesis was earlier under cyclic light (LD) condition when compared to constant dark (DD), resulting in more synapses at earlier developmental stages. The effect of light was also supported by micro electroretinography showing larger responses under LD condition. The number of synapses was also increased after transplantation of mouse iPSC-retinas to rd1 mice under LD condition. Our new probabilistic assessment of synapses may prove to be a valuable tool to gain critical insights into neural-network reconstruction and help develop treatments for neurodegenerative disorders.