Search for author "Zhaohua Cai"

Figure 1. Analysis of angiogenic factor gene expression in cultured cells. Primary cultures of cardiac myocytes (A), cardiac fibroblasts (B), arterial endothelial cells (C), or arterial SMCs (D) were incubated for 24 hours under nonhypoxic (20% O2) or hypoxic (1% O2) conditions or under nonhypoxic conditions in the presence of AdLacZ or AdCA5 at a multiplicity of infection of 25 pfu/cell. Total RNA was analyzed by RT-PCR. E, Structure of HIF-1α and CA5. The basic helix-loop-helix (bHLH) and PAS domains of HIF-1α that are required for dimerization with HIF-1β and DNA binding are intact in CA5, as are the amino- and carboxyl-terminal transactivation domains (TAD-N and TAD-C, respectively). However, O2-dependent degradation of HIF-1α under nonhypoxic conditions is impaired by deletion of amino acids 392 through 520 and the missense mutations Pro567Thr (P567Q) and Pro658Gln (P658Q). F, Summary of changes in gene expression induced by hypoxia or AdCA5. Exposure of cardiac myocytes (CM), cardiac fibroblasts (CF), arterial ECs (EC), and arterial SMCs (SM) to 1% O2 or AdCA5 infection either increased (green), decreased (red), or had no effect (yellow) on the expression of the indicated angiogenic growth factor mRNAs relative to the appropriate control (20% O2 and AdLacZ infection, respectively). G, Gene expression in ES cells. Real-time RT-PCR was performed to analyze total RNA isolated from Hif1a+/+ and Hif1a−/− ES cells that were incubated under nonhypoxic (20% O2) or hypoxic (1% O2) conditions for 24 hours. The mean (n=3) fold induction in hypoxic cells is shown for each mRNA.Show Less

Figure 3. Immunohistochemical analyses of HIF-1α and PLGF expression. Tissue was harvested from AdCA5- and AdLacZ-injected eyes 24 hours or 6 days after subretinal injection, and sections were stained with antibodies against HIF-1α or PLGF, respectively. HIF-1α expression is observed at the site of AdCA5 injection (arrows). In AdCA5-injected eyes, PLGF expression is prominent in the INL (vertical arrows) with vertical lines in the inner plexiform layer (horizontal arrows) typical of Muller cell processes and irregular horizontal linear-stained structures near the surface of the retina (arrowheads) typical of Muller cell end feet. In AdLacZ-injected eyes, modest PLGF staining is observed in the INL and near the retinal surface.Show Less

Figure 5. Histochemical analysis of retinal vasculature after intravitreous injection. Sections from the indicated regions of mouse eyes that received an intravitreous injection of AdCA5 or AdLacZ 6 days earlier were stained with GSA lectin or anti-SMA antibodies. Left (red box), In sections from AdCA5-injected eyes, retinal neovascular tufts (arrows) were seen projecting above the inner limiting membrane (ILM; demarcated by arrowheads). Right (green box), Corneal neovascularization that stained positively for GSA and SMA (arrows) was observed in AdCA5-injected eyes but not in AdLacZ-injected eyes. There was also staining for GSA and SMA in the iridocorneal angle (arrowheads).Show Less

Figure 7. Regulation of angiogenesis by HIF-1. In a cell type–specific manner, HIF-1 can either activate (arrow) or repress (blocked arrow) expression of genes encoding angiogenic growth factors (PLGF, VEGF, ANGPT1, ANGPT2, and PDGFB) that bind to receptors (VEGFR1, VEGFR2, TIE2, and PDGFR) on vascular ECs or SMCs. Receptor signaling leads to critical events required for physiological angiogenesis.Show Less