2017 Fiscal Year Research-status Report
The coordinating roles of ITGb3 for adult neurogenesis-mediated homeostatic synaptic scaling and innate anxiety
| Project/Area Number |
17K18367
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
PARK YUNKYUNG 国立研究開発法人理化学研究所, 脳科学総合研究センター, 研究員 (50568863)
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| Project Period (FY) |
2017-04-01 – 2019-03-31
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| Keywords | circuit specificity / mossy fiber bouton / synaptoporin / CA3 pyramidal neurons / adult neurogenesis |
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| Outline of Annual Research Achievements |
Current research found out that total number of neurons and adult neurogenesis rate in dentate gyrus (DG) were not different in ITGb3 null mice. Also these mice did not show the difference in gross anatomy of mossy fiber (MF) projection such as the length in stratum lucidum of CA3 and the hilus area within DG. However, reduction in averaged size of synaptoporin (MF-specific synaptic vesicle protein) punta in null mice indicates the release property change in MF bouton.
On the other hand, field recording from mice which lack ITGb3 only in CA3 excitatory neuron exhibited reduced CA3 output with unaltered afferent fiber volley.
Altogether, it suggests that expression of ITGb3 in both MF bouton and CA3 neurons is required to modulate the excitatory synaptic transmission in hippocampus.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
There were several technical reasons for delay.
One was the animal. The breeding of conditional floxed mice, which was generated via Cas9 system in our lab, and their cross-breeding with transgenic mice expressing Cre only in CA3 pyramidal neurons were more delayed than originally planned. Also it took a while to complete the validation tests for Cre-dependent protein knockout effect using these mice, although it was succesfully done and this result was presented in conference.
Second is delayed installation of newly purchased equipments such as microscope and light source.
The last is the limitated imaging resolution of DG-CA3 synapse labed by conventional fluorescent probe in preliminary experiments.
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| Strategy for Future Research Activity |
To overcome poor resolution of MF bouton and thorny excrescence (TE) of CA3 neurons, we tested the feasibility of several labeling method such as utilizing membrane tagging probe together with a newly developed hyperantigenic probe spagetthi monster. Systemic morphology analysis of MF boutons in adult-born and matured DG neurons and TE of CA3 pyramidal neurons will be performed by above method.
Also DG-specific knockdown effect by injecting Cre-carrying virus into DG of conditionally floxed mice will be carried out.
Testing the ostsynaptic knockdown effect on quantal amplitude of EPSC in MF-TE synapses and network oscillation is under progress.
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