Figure 3

Differential localization of nidogen isoforms in peripheral nerve. (A, B) Nidogens are differentially localized in the basal laminas (BLs) associated with intramuscular nerve fascicles. Whereas nidogen-1 is present at similar levels in both peri- and endoneurial BL, nidogen-2 is enriched in perineurial BL. Most endoneurial BL expressed little nidogen-2, but a few structures within the nerve fascicle did contain nidogen-2 (arrowheads). Double staining with antibodies to CD31/PECAM indicate that most nidogen-2-positive structures within nerve fascicles are not associated with capillaries (data not shown). (C, D) Nidogens are differentially localized in BLs associated with sensory muscle spindles. Nidogen-1 is enriched in BLs surrounding individual intrafusal fibers within the muscle spindle, but nidogen-2 is enriched in the capsular BL surrounding the entire spindle. (E-H) Nidogen-1 and 2 are both present in BLs associated with vascular structures, including capillaries (E, F; arrowheads in E, G, H highlight capillary BL) and arterioles (arrows in G, H). Scale bar in (B) is 20 μm for (A, B), in (D) is 10 μm for (C, D), in (F) is 20 μm for (E, F), and in (H) is 20 μm for (G, H).