Rescue of Rod Synapses by Induction of Cav Alpha 1F in the Mature Cav1.4 Knock-Out Mouse Retina
Rescue of Rod Synapses by Induction of Cav Alpha 1F in the Mature Cav1.4 Knock-Out Mouse Retina
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DOI：
10.1167/iovs.19-27226
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发表时间：
2019-07-01
影响因子：
4.4
通讯作者：
Baker, Sheila A.
中科院分区：
文献类型：
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作者：
Laird, Joseph G.;Gardner, Sarah H.;Baker, Sheila A.
目的. Ca（v）1.4是聚集在光感受器突触前活动区的电压门控钙通道。Ca（v）1.4通过介导触发神经递质释放的Ca 2+内流在通信中起作用。它还有助于发育，因为在Ca（v）1.4敲除小鼠中不会形成杆带突触。在这里，我们使用了一种拯救策略来研究Ca（v）1.4在未成熟和成熟小鼠视杆中触发突触发生的能力。使用体内电穿孔在Ca（v）1.4敲除小鼠杆的子集中瞬时表达Ca-v α（1F）或他莫昔芬诱导的Ca-v α（1F）。使用形态学标记和视觉引导的水迷宫检测突触发生。我们发现，引入Ca-v α（1F）敲除终端拯救突触发育所示的PSD-95表达和细长的丝带。当在成熟动物中诱导Ca-v α（1F）的表达时，我们再次发现PSD-95的恢复和延长的条带。然而，Ca-v α（1F）的诱导表达导致Ca-v α（1F）在终末弥散分布，而不是聚集在带状物下方。大约四分之一的治疗动物通过了水迷宫测试，表明这些小鼠中视网膜信号的拯救。这些数据证实了Ca-v α（1F）表达是视杆突触末端发育所必需的，并表明即使在突触疾病晚期的成年动物中，拯救也是稳健的。这里看到的视杆突触可塑性的程度应该足以支持未来的视力恢复治疗，如基因或细胞替代，这将需要感光突触重新布线。
PURPOSE. Ca(v)1.4 is a voltage-gated calcium channel clustered at the presynaptic active zones of photoreceptors. Ca(v)1.4 functions in communication by mediating the Ca2+ influx that triggers neurotransmitter release. It also aids in development since rod ribbon synapses do not form in Ca(v)1.4 knock-out mice. Here we used a rescue strategy to investigate the ability of Ca(v)1.4 to trigger synaptogenesis in both immature and mature mouse rods.METHODS. In vivo electroporation was used to transiently express Ca-v alpha(1F) or tamoxifeninducible Ca-v alpha(1F) in a subset of Ca(v)1.4 knock-out mouse rods. Synaptogenesis was assayed using morphologic markers and a vision-guided water maze.RESULTS. We found that introduction of Ca-v alpha(1F) to knock-out terminals rescued synaptic development as indicated by PSD-95 expression and elongated ribbons. When expression of Ca-v alpha(1F) was induced in mature animals, we again found restoration of PSD-95 and elongated ribbons. However, the induced expression of Ca-v alpha(1F) led to diffuse distribution of Ca-v alpha(1F) in the terminal instead of being clustered beneath the ribbon. Approximately a quarter of treated animals passed the water maze test, suggesting the rescue of retinal signaling in these mice.CONCLUSIONS. These data confirm that Ca-v alpha(1F) expression is necessary for rod synaptic terminal development and demonstrate that rescue is robust even in adult animals with late stages of synaptic disease. The degree of rod synaptic plasticity seen here should be sufficient to support future vision-restoring treatments such as gene or cell replacement that will require photoreceptor synaptic rewiring.