A role for endothelial cells in promoting the maturation of astrocytes through the apelin/APJ system in mice

Abstract

SUMMARYInteractions between astrocytes and endothelial cells (ECs) are crucial for retinal vascular formation. Astrocytes induce migration and proliferation of ECs via their production of vascular endothelial growth factor (VEGF) and, conversely, ECs induce maturation of astrocytes possibly by the secretion of leukemia inhibitory factor (LIF). Together with the maturation of astrocytes, this finalizes angiogenesis. Thus far, the mechanisms triggering LIF production in ECs are unclear. Here we show that apelin, a ligand for the endothelial receptor APJ, induces maturation of astrocytes mediated by the production of LIF from ECs. APJ (Aplnr)-and Aplndeficient mice show delayed angiogenesis; however, aberrant overgrowth of endothelial networks with immature astrocyte overgrowth was induced. When ECs were stimulated with apelin, LIF expression was upregulated and intraocular injection of LIF into APJ-deficient mice suppressed EC and astrocyte overgrowth. These data suggest an involvement of apelin/APJ in the maturation process of retinal angiogenesis.

Arf6 regulates tumour angiogenesis and growth through HGF-induced endothelial β1 integrin recycling

“…In situ hybridization for Arf6 was performed as previously described 53 . Briefly, E13.5 embryos were fixed with 4% paraformaldehyde (PFA)/PBS, and embedded in optimal cutting temperature compound to prepare cryostat sections.…”

CD44 expression in endothelial colony-forming cells regulates neurovascular trophic effect

“…For retinal and post-capsular flat-mounts, we dissected only the cornea, choroid, and sclera from enucleated eyes, and then we punctured the anterior capsule of the lens and removed the nuclei and cortex of the lens with forceps. Immunostaining of cryosections was carried out as previously described (51). The primary antibodies used in this study are described in Supplemental Table 1.…”

Identification of Vascular Endothelial Side Population Cells in the Choroidal Vessels and Their Potential Role in Age-Related Macular Degeneration

“…Respective tissue was excised, minced, and digested with Dispase II (Godo Shusei Corp., Chiba, Japan), collagenase (Wako, Osaka, Japan), and type II collagenase (Worthington Biochemical Corp., Lakewood, NJ) at 378C. 17 The digested tissue was passed through 40-lm filters to yield single cell suspensions. Erythrocytes were lysed with ACK buffer (0.15 M NH 4 Cl, 10 mM KHCO 3 , and 0.1 mM Na 2 -EDTA).…”