アストロサイトとシナプスのコンタクトダイナミックスの機構

2015 Fiscal Year Annual Research Report

• Project/Area Number: 15H04280
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: 合田 裕紀子 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, チームリーダー (40614897)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: synapse / astrocyte / hGFAP promoter

Outline of Annual Research Achievements

Our overall goal is to assess the mechanisms underlying the dynamic interaction between astrocytes and synapses. Towards this end, we have prepared probes to visualize and manipulate activity of hippocampal astrocytes. Although detailed interaction studies might be better suited to be performed in dissociated cultures, it is also necessary to study the interaction in native hippocampal networks. We have therefore prepared AAV vectors that would allow for the expression of the probes in mice brains and subsequent analysis in acute hippocampal slices. Initially, some difficulties were encountered due to differences in the specificity of astrocyte expression between different versions of the hGFAP promoter in dissociated cultures and in acute brain. In acute brain expression, we were able to control the degree of misexpression of astrocyte-specific probes in neurons in hippocampal area CA1 to less than 1% by fine tuning the virus titre and the duration of virus expression. In dissociated cultures, we found that the method of transfection often biased the expression between neurons or astrocytes. We circumvented the issue by first using pure astrocyte cultures to transfect with the astrocyte expression vectors, and then subsequently plating neurons on top to let the formation of astrocyte and neuronal networks.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

In the initial year, we encountered some delays in the project that were associated with the hiring of the appropriate personnel dedicated to the project. Nevertheless, with the funds that were carried forward, we were able to effectively implement the execution of the experiments to catch up with the overall plan.

Strategy for Future Research Activity

We will continue implementing the astrocyte-specific probes to characterize the basis of the interaction between asrtocyte and synapses, with the particular emphasis on the role for astrocyte gap junction proteins and actin dynamics.