Figure 4.

Microglia in demyelinated grey matter (GML) of leucocortical lesions upregulate ITGAX and are potentially neuroprotective. qPCR validation of RNA-seq results showing increase mRNA levels of ITGAX in GML versus NAGM and WML versus NAWM (A). Semi-automatic quantification of immunohistochemistry for CD11c (ITGAX) indicated increased count of CD11c⁺ cells in GMLs compared with NAGM but not WML compared with NAWM (B, left side). The number of Iba-1⁺/CD11c⁺ cells increased significantly in WMLs versus NAWM but not in GML versus NAGM (B, right side). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, ns = non-significant as shown by linear mixed models. ROI for quantification: 0.36 mm². N = 6 for qPCR, N = 11 for quantification of CD11c counts, N = 6 to assess co-localization of CD11c and Iba-1. Representative images of immunohistochemical stainings of CD11c (ITGAX) and Iba-1 showing co-localization (C–F). Co-localization of CD11c and CD68 indicating phagocytic activity in both amoeboid (G) and ramified (H) CD11c⁺ microglia. Microglia in GMLs of leucocortical lesions show decreased complexity as indicated by the lower total length of the processes (I) and less forking points (J). *P < 0.05 as shown by mixed models. Scale bar, 50 µm. N = 109 per lesion area with individually traced microglia. WML, white matter lesion; GML, grey matter lesion; NAWM, normal-appearing white matter; NAGM, normal-appearing grey matter.