AUTHOR=Ding Fusheng , Liang Shanshan , Li Ruijie , Yang Zhiqi , He Yong , Yang Shaofan , Duan Qingtian , Zhang Jianxiong , Lyu Jing , Zhou Zhenqiao , Huang Mingzhu , Wang Haoyu , Li Jin , Yang Chuanyan , Wang Yuxia , Gong Mingyue , Chen Shangbin , Jia Hongbo , Chen Xiaowei , Liao Xiang , Fu Ling , Zhang Kuan TITLE=Astrocytes exhibit diverse Ca2+ changes at subcellular domains during brain aging JOURNAL=Frontiers in Aging Neuroscience VOLUME=14 YEAR=2022 URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2022.1029533 DOI=10.3389/fnagi.2022.1029533 ISSN=1663-4365 ABSTRACT=

Astrocytic Ca2+ transients are essential for astrocyte integration into neural circuits. These Ca2+ transients are primarily sequestered in subcellular domains, including primary branches, branchlets and leaflets, and endfeet. In previous studies, it suggests that aging causes functional defects in astrocytes. Until now, it was unclear whether and how aging affects astrocytic Ca2+ transients at subcellular domains. In this study, we combined a genetically encoded Ca2+ sensor (GCaMP6f) and in vivo two-photon Ca2+ imaging to determine changes in Ca2+ transients within astrocytic subcellular domains during brain aging. We showed that aging increased Ca2+ transients in astrocytic primary branches, higher-order branchlets, and terminal leaflets. However, Ca2+ transients decreased within astrocytic endfeet during brain aging, which could be caused by the decreased expressions of Aquaporin-4 (AQP4). In addition, aging-induced changes of Ca2+ transient types were heterogeneous within astrocytic subcellular domains. These results demonstrate that the astrocytic Ca2+ transients within subcellular domains are affected by aging differently. This finding contributes to a better understanding of the physiological role of astrocytes in aging-induced neural circuit degeneration.