Fig. 9

Astrocytes, AR and CXCR4 are highly expressed at the border of human white matter MS lesions. a–d Coronal section of the thoracic spinal cord from a female MS patient with 3 mixed active/inactive (chronic active) lesions were immunostained for MBP, CXCR4 and MPZ. The center and RIM of a lesion are delimited by dotted lines. NAWM = Normal Appearing White Matter. Scale bar: 1 mm. e–h Enlarged image of a lesion RIM immunostained for GFAP, CXCR4 and MPZ. GFAP and CXCR4 colocalized, indicating CXCR4 expressing astrocytes, and their immunostaining never overlapped with the Schwann cell marker MPZ (arrows). The MPZ⁺ Schwann cells most likely originated from nearby spinal nerve roots (indicated by stars). Scale bar: 30 µm. i and j Enlarged view of the colocalization of CXCR4 and MBP at the RIM, which was excluded of MPZ⁺ immunostaining. Scale bar: 50 µm. k and l GFAP and AR immunostaining colocalized and were exclusive to MPZ⁺ Schwann cells, most likely originating from nearby spinal nerve roots (star). Scale bar: 50 µm. m–p Quantification of MBP (m), CXCR4 (n), GFAP (o) and CXCR4/GFAP immunostaining (p) and counting of AR⁺ cells (q) within the lesion center, lesion RIM and NAWM of the MS lesions identified on spinal cord sections from the 10 MS patients (5 men and 5 women). Lesion is delimited by the dotted line. Data are presented as means ± S.E.M. (one-way ANOVA with Tukey's multiple comparisons tests). Asterisks mark significant differences. ***P < 0.001, **P < 0.01