Local and CNS-Wide Astrocyte Intracellular Calcium Signaling Attenuation In Vivo with CalExflox Mice

Astrocytes exist throughout the CNS and affect neural circuits and behavior through intracellular Ca2+ signaling. Studying the function(s) of astrocyte Ca2+ signaling has proven difficult because of the paucity of tools to achieve selective attenuation. Based on recent studies, we generated and used male and female knock-in mice for Cre-dependent expression of mCherrytagged hPMCA2w/b to attenuate astrocyte Ca2+ signaling in genetically defined cells in vivo (CalExflox mice for Calcium Extrusion). We characterized CalEx(flox) mice following local AAV-Cre microinjections into the striatum and found reduced astrocyte Ca2+ signaling (similar to 90%) accompanied with repetitive self-grooming behavior. We also crossed CalExflox mice to astrocyte-specific Aldh1l1-Cre/ERT2 mice to achieve inducible global CNS-wide Ca2+ signaling attenuation. Within 6 d of induction in the bigenic mice, we observed significantly altered ambulation in the open field, disrupted motor coordination and gait, and premature lethality. Furthermore, with histologic, imaging, and transcriptomic analyses, we identified cellular and molecular alterations in the cerebellum following mCherry-tagged hPMCA2w/b expression. Our data show that expression of mCherry-tagged hPMCA2w/b with CalExflox mice throughout the CNS resulted in substantial attenuation of astrocyte Ca2+ signaling and significant behavioral alterations in adult mice. We interpreted these findings candidly in relation to the ability of CalEx to attenuate astrocyte Ca2+ signaling, with regards to additional mechanistic interpretations of the data, and their relation to past studies that reduced astrocyte Ca2+ signaling throughout the CNS. The data and resources provide complementary ways to interrogate the function(s) of astrocytes in multiple experimental scenarios.

Automated summary

By attenuating astrocyte calcium signaling in vivo using specific mouse models, researchers observed significant behavioral alterations in adult mice. Additionally, this attenuation led to cellular and molecular changes, particularly in the cerebellum. These findings provide valuable insights into the role of astrocytes in neural circuits and behavior.