Angiopoietin-1 Guides Directional Angiogenesis Through Integrin α _v β ₅ Signaling for Recovery of Ischemic Retinopathy

Abstract

Retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR) are ischemic retinal diseases caused by insufficient vascular network formation and vascular regression in addition to aberrant angiogenesis. We examined the role of angiopoietin-1 (Ang1) in retinal vascular network formation during postnatal development using Ang1 gain- and loss-of-function mouse models, and tested the effects of intraocular administration of Ang1 in an oxygen-induced retinopathy (OIR) mouse model that mimics cardinal features of ROP and PDR. We observed that Ang1 plays a substantial role in the formation of the retinal vascular network during postnatal development and that Ang1 supplementation can rescue vascular retinopathies by simultaneously promoting healthy vascular network formation and inhibiting subsequent abnormal angiogenesis, vascular leakage, and neuronal dysfunction in the retinas of the OIR model. We attribute these Ang1-induced effects to a dual signaling pathway-Tie2 signaling in the vascular region and integrin αvβ5 signaling in the astrocytes. The activation of integrin αvβ5 signaling promoted fibronectin accumulation and radial distribution along the sprouting endothelial cells, which consequently stimulated guided angiogenesis in the retina. These findings shed light on the role of Ang1 in the recovery of ischemic retinopathies such as ROP, PDR, and retinal vascular occlusive disease.

Inhibition of Ninjurin 1 restores erectile function through dual angiogenic and neurotrophic effects in the diabetic mouse

“…Inhibition of the Ang1-Tie2 signaling pathway with sTie2-Fc or Ang1 siRNA abolished the Ninj1 blockade-mediated increase in neurotrophic factors and restoration of nNOS-positive neurons in diabetic mice in vivo and in neuro2A cells in vitro. A recent study reported that Ang1 inhibits apoptosis of retinal neurons and prevents neuronal dysfunction in a mouse model of oxygeninduced retinopathy (31). Thus, Ang1 may have a protective effect on ischemia-induced neuronal loss.…”

Lymphatic regulator PROX1 determines Schlemm’s canal integrity and identity

“…The group with the highest intensity was normal- All measurements were performed in at least 5 different SC per cornea, excluding the portion of the bifurcation of LPCAs, unless indicated otherwise. Radial length of BVs and number of filopodia in the retina were counted as previously described (60). Intravital imaging.…”

“…Frozen blocks were cut into 10-μm sections. IHC in whole-mounted retinas was performed as previously described (60). The whole corneas or sectioned corneas or retinas were incubated with 1 or more of the following antibodies: anti-CD31 (hamster monoclonal, clone 2H8; Millipore); anti-PDGFRβ (rat monoclonal, clone APB5; eBioscience); FITC-, or Cy3-conjugated anti-α-SMA (mouse monoclonal, clone 1A4; Sigma-Aldrich); anti-Prox1 (rabbit polyclonal; ReliaTech); antiProx1 (goat polyclonal; R&D); anti-VEGFR3 (goat polyclonal; R&D); anti-endomucin (rat polyclonal; Santa Cruz Biotechnology Inc.); antiItga9 (goat polyclonal; R&D); anti-podoplanin (hamster polyclonal; AngioBio); anti-VE-cadherin (rat monoclonal, clone 11D4.1; BD Biosciences -Pharmingen); anti-LYVE-1 (rabbit polyclonal; AngioBio); anti-collagen type IV (rabbit polyclonal; Cosmo Bio); anti-Sox18 (rabbit polyclonal; Aviva System Biology); anti-Foxc2 (sheep polyclonal; R&D); anti-integrin β 1 (rat monoclonal, clone 9EG7; BD Biosciences); anti-CD31 (rat monoclonal, clone MEC 13.3; BD Biosciences); anti-VEGFR2 (rabbit monoclonal, TO14; a gift from Rolf A. Brekken, Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA); anti-phosphohistone H3 (PH3) (rabbit polyclonal; Millipore); anti-caspase-3 (rabbit polyclonal; R&D); anti-Klf4 (goat polyclonal; R&D); anti-eNOS (mouse monoclonal; BD Bioscience); anti-vWF (rabbit polyclonal; Chemicon); anti-vimentin (goat polyclonal; Chemicon); anti-FSP-1 (rabbit polyclonal; Abcam); anti-desmin (rabbit monoclonal, clone Y66; Millipore); anti-MMP-2 (rabbit polyclonal; Abcam); anti-MMP-9 (goat polyclonal; R&D); and anti-TER119 (rat monoclonal, clone TER-119; eBioscience).…”

Perilipin+ embryonic preadipocytes actively proliferate along growing vasculatures for adipose expansion

“…VEGFR2 +/fl (Albuquerque et al, 2009) mice were kindly provided by Professor Masanori Hirashima (Kobe University, Japan). VE-Cadherin-Cre-ER T2 (Wang et al, 2010), Col1a1-Cre (Liu et al, 2004), inducible COMP-Ang1-Tg (Lee et al, 2013) and mT/mG (Muzumdar et al, 2007) mice were transferred and bred in our specific pathogen-free animal facilities at KAIST. Tamoxifen (SigmaAldrich) was dissolved in corn oil and administrated into the peritoneal cavity of pregnant females (3.0 mg/mouse) at the indicated time point.…”