2023 Fiscal Year Research-status Report
| Project/Area Number |
23K06303
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| Research Institution | Osaka University |
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Principal Investigator |
Tu HungYa 大阪大学, 蛋白質研究所, 助教 (10780835)
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| Project Period (FY) |
2023-04-01 – 2026-03-31
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| Keywords | retina / synapse / photoreceptor cell / bipolar cell / deconstruction / reconstruction |
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| Outline of Annual Research Achievements |
The purpose of this project is to elucidate 1) whether the photoreceptor and bipolar cells still possess the plasticity and potential to reorganize their synaptic connection in the mature mammalian retina, and 2) based on that how the cell replacement based therapy may be advanced. We first established the mouse models of inducible photoreceptor-bipolar synaptic deconstruction and reconstruction, both partially and completely, using the CreERT2 system. Tamoxifen-inducible conditional knockout (CKO) of Pikachurin, the one presumably resulting in partial synaptic impairment by depleting the photoreceptor-origin synaptic organizer, has been first launched and showed a limited time window right after the retinal circuitry is established, to effectively disrupt the synaptic organization followed by a delayed functional reduction, suggesting the Pikachurin proteins may be protected after implemented into the synapse and have a slow turn-over rate, or there is at least a limited period for the synapses to retain their structures even without the synaptic organizer. The mouse line for the (presumable) complete synaptic deconstruction by removing Trpm1, one of the key component on the bipolar cell side, has recently become ready, as well as the conditional rescue models of these two CKO models.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The preparation of mouse lines took slightly longer than expected due to the need for clearance of mouse strain background issue and the limited breeding yields because of the complexity of combining multiple CreERT2 lines and fluorescence-based reporter lines. However, with the first-launched CKO line, the protocol of tamoxifen-based induction has been established, with an effective time window identified preliminarily.
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| Strategy for Future Research Activity |
By retinal immunohistochemistry and electrophysiology at both animal-level (optokinetic response) and cell-level (multielectrode array recording), the structural and functional potential of synaptic deconstruction and, more importantly, reconstruction will be evaluated in detail to provide insight for cell replacement based therapeutic advancement.
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