Fig. 8.

Astrocytic Itga6 expression is upregulated in Apcdd1^−/− retinas. (A) P10 Apcdd1^−/− retinal flat-mounts stained for Lef1, Pdgfrα and DAPI. Yellow arrowheads indicate Lef1⁻ astrocytes. (B-G) P14 WT retinal flat-mounts stained for either integrin-α2 (B-D) or Itga6 (E-G) and GFAP. Unfilled arrowheads indicate the lack of integrin-α2 expression in astrocytes. Filled arrowheads indicate Itga6 expression in astrocytes. (H-Q) P14 WT and Apcdd1^−/− retinal flat-mounts stained for Itga6 and GFAP in arteries (H-K′) and veins (M-P′). A, artery; V, vein. Corresponding boxed areas are magnified in I′,K′,N′,P′. Ratio of Itga6/GFAP M.F.I. in peri-arterial (L) and perivenous (Q) astrocytes, normalized to WT average values (ten arteries from n=5 mice/group at P10 and 12 arteries from n=6 mice/group at P14). (R-U) Primary mouse brain astrocytes were cultured on laminin-211-coated plates in the presence of either Itga6-blocking antibodies (Abs) or heat-killed Itga6-blocking Abs (control), and stained for Pdgfrα, GFAP, Aqp4 and DAPI. (V) GFAP⁺ and Aqp4⁺ astrocyte area (n=3 independent experiments). (W) Proposed model by which mural Wnt/β-catenin signaling regulates Lama2 deposition to the vBM and NVU maturation (see Discussion). Data are mean±s.e.m., analyzed with two-tailed unpaired Student's t-test: **P<0.02.