Local and CNS-Wide astrocyte intracellular calcium signaling attenuation in vivo with CalEx^flox mice

Astrocytes exist throughout the CNS and affect neural circuits and behavior through intracellular Ca²¹ signaling. Studying the function(s) of astrocyte Ca²¹ 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 mCherry-tagged hPMCA2w/b to attenuate astrocyte Ca²¹ signaling in genetically defined cells in vivo (CalEx^flox mice for Calcium Extrusion). We characterized CalEx^flox mice following local AAV-Cre microinjections into the striatum and found reduced astrocyte Ca²¹ signaling (;90%) accompanied with repetitive self-grooming behavior. We also crossed CalEx^flox mice to astrocyte-specific Aldh1l1-Cre/ERT2 mice to achieve inducible global CNS-wide Ca²¹ 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 CalEx^flox mice throughout the CNS resulted in substantial attenuation of astrocyte Ca²¹ signaling and significant behavioral alterations in adult mice. We interpreted these findings candidly in relation to the ability of CalEx to attenuate astrocyte Ca²¹ signaling, with regards to additional mechanistic interpretations of the data, and their relation to past studies that reduced astrocyte Ca²¹ signaling throughout the CNS. The data and resources provide complementary ways to interrogate the function(s) of astrocytes in multiple experimental scenarios.