McCarthy-de Vellis astrocytes express elevated levels of reactive gliosis genes. A, The Venn diagram shows the distribution of genes significantly induced more than fourfold in LPS and MCAO reactive astrocytes and significantly expressed more than fourfold more in MD-astrocytes relative to astrocytes in vivo. More than 50% of astrocyte reactive gliosis genes are elevated in MD-astrocytes relative to astrocytes in vivo. B, The dendrogram represented in Euclidean distance was generated by hierarchical clustering of the quiescent, reactive, and MD-astrocyte expression profiles using the 263 more than fourfold induced reactive astrocyte genes. MD-astrocytes cluster most strongly with MCAO reactive astrocytes and away from all three groups of quiescent astrocytes. C, Hierarchical clustering represented in Euclidean distance of the quiescent, reactive, and MD-astrocyte expression profiles using class subsets of genes. Using the cytokine signaling genes, ECM binding/adhesion genes, and IL6 signaling pathway, MD-astrocytes cluster most closely with MCAO reactive astrocytes. Using the complement pathway and interferon response genes, MD-astrocytes cluster most closely with the LPS reactive astrocytes. Using transporter/channel genes, peptidase inhibitors, and acute phase signaling, MD-astrocytes cluster with both subtypes of reactive astrocytes. Using the antigen presentation pathway, MD-astrocytes cluster with quiescent astrocytes.