Fig 2: A Heatmap of 314 differentially expressed genes for control versus CSF1 OE samples. Each row represents a single gene, while each column represents a sample. Two hundred fourteen genes are upregulated (shown in red) in the CSF1 OE condition and one hundred are downregulated (shown in green). Genes are shown in the order depicted in Supplemental Table 1, and the rows for the M2 markers Ccl24 and Retnla are indicated. B GO terms enriched in differentially expressed genes between microglia from CSF1 OE and control mice. Benjamini–Hochberg corrected p values are presented

Fig 3: CSF1 OE does not impact the expression of astrocytic genes. A Quantification of the percent of cells that are GFAP+ astrocytes in the cerebellar white matter of control (CON, white shaded bars) or CSF1 OE (OE, grey shaded bars) at p14 and 1 year. RT-qPCR for Gfap (B), Slc1a2 (C), and C3 (D) on mRNA isolated from half brain hemispheres of control (CON, white shaded bars) or CSF1 OE (OE, grey shaded bars) mice at age p14 or 1 year. ns = non-significant (p > 0.05), unpaired, two-tailed t test

Fig 4: CSF1 OE does not impact the expression of genes expressed in the oligodendrocyte lineage. Quantification of the percent of cells that are OPCs (OLIG2+; PDGFRA+) (A) or mature or maturing oligodendrocytes (OLIG2+; PDGFRA-) (B) in the cerebellar white matter of control (CON, white shaded bars) or CSF1 OE (OE, grey shaded bars) at p14 and 1 year. RT-qPCR for Pdgfra (C), Olig2 (D), and Mog (E) on mRNA isolated from half brain hemispheres of control (CON, white shaded bars) or CSF1 OE (OE, grey shaded bars) mice at p14 and 1 year. ns = non-significant (p > 0.05), unpaired, two-tailed t test

Fig 5: CSF1 OE does not increase expression of M2 markers, even in aged mice. A Representative images of immunofluorescence for ARG1 (green) with IBA1 (red) in the indicated brain regions in CSF1 OE mice at p14 and 1 year. DAPI (blue) is also shown in the merged image. Arrowheads indicate examples of IBA1+ ARG1- cells while an asterisk indicates an example of lipofuscin autofluorescence that was also visible in additional channels (not shown). B Representative images of immunofluorescence for MRC1 (CD206) (green) with IBA1 (red) in the indicated brain regions in CSF1 OE mice at p14 and 1 year. Arrowheads indicate examples of IBA1+ MRC1- parenchymal microglia and arrows indicate MRC1+ perivascular macrophages residing next to blood vessels that stain with lectin (in white, lectin staining is also present as expected in microglia). DAPI (blue) is also shown in the merged image. Scale bars = 25 µ. RT-qPCR for Arg1 (C) and Mrc1 (D) in p14 and 1-year mice on mRNA isolated from half brain hemispheres of control (CON, white shaded bars) or CSF1 OE (OE, grey shaded bars) mice. ns = non-significant (p > 0.05), unpaired, two-tailed t test