Astrocytes and microglia establish physical interactions during CNS inflammation

To investigate astrocyte-microglia interactions in vivo, we took advantage of the recombinant rabies virus (RV). We used glycoprotein G-deficient RV expressing the fluorescent protein mCherry and pseudotyped with glycoprotein EnvA, in combination with GFAP-Cre RABVgp4/TVA transgenic mice that express TVA protein and glycoprotein G in astrocytes under the control of the Gfap promoter. Following injection into GfapRABVgp4/TVA mice, RV initially infects TVA expressing astrocytes, and following its replication RV infect cells in direct contact with astrocytes. We then sorted mCherry+ or mCherry- microglia on EAE mice and prove that microglia that had interacted with astrocytes had a more proinflammatory transcriptional profile. Microglia were isolated from CNS of Gfap-RABVgp4/TVA mice undergoing EAE that had been transduced with Rab-deltaG-mCherry EnvA pseudotyped a week in advanced.