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. 2010 Feb;176(2):839–849. doi: 10.2353/ajpath.2010.090570

Figure 6.

Figure 6

Immunofluorescence microscopy: patterns and transitions in laminin isoforms. Kidneys from wt and ko mice were stained with antibodies to the following proteins: A: LN111, LNα1, LNα2, LNα3. Anti-LN111 stains all kidney basement membranes showing overall structure. Typically this antibody stains mesangial matrix more brightly than GBM. This was true in wild-type and lama4−/− mice. Note the irregular organization of mesangial matrix and wide separation between adjacent tubular basement membranes, which represents the space occupied by dilated peritubular capillaries. In the mouse, staining for LNα1 is normally detected in GBM at early stages of glomerulogenesis, and disappears from this site as glomerulogenesis is completed, with detectable LNα1 remaining in the mesangium and TBM of proximal tubules. These transitions in LNα1 were identical in 7-to 14-week-old wild-type and lama4−/− mice. Note the absence of glomerular staining for LNα2 in lama4−/− mice (arrow) and the increase in staining around afferent and efferent arterioles at the glomerular hilum. LNα3 has a limited distribution on the endothelial side of GBM. No significant change in LNα3 was identified in lama4−/− mice. B: LNα4, LNα5, LNβ1, and LNβ2. LNα4 is detected in the mesangial matrix and surrounding peritubular capillaries in wild-type mice and is not detected in lama4−/− mice. During normal glomerulogenesis, LNα5 replaces LNα1 in the GBM and it facilitates maturation and condensation of the mesangium. LNα5 is a normal component of TBM and the peritubular capillary basement membrane. In lama4−/− mice, LNα5 staining of GBM, mesangial matrix, TBM and peritubular capillaries was not different from wild-type mice; however, structural differences in the mesangium were apparent with staining for this LN chain. The brightly stained, condensed mature mesangium was not uniformly present in lama4−/− mice. As glomeruli become fully mature, LNβ1 in GBM is replaced by LNβ2. This transition occurred normally in lama4−/− mice. In wild-type and lama4−/− mice, LNβ1 persists in other ECM compartments including the mesangium and TBM. Adjacent to TBM, a fibrillar matrix that supports peritubular capillaries normally contains LN411 and LN511. Of note, LNβ1 was not detected in this location, but LNβ2 was abundant, which indicates that peritubular capillary matrix is altered and contains only LN521 in lama4−/− mice.