41 research outputs found

    A mouse model for Sorsby fundus dystrophy

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    purpose. Sorsby fundus dystrophy (SFD) is a rare, late-onset macular dystrophy caused by mutations in the tissue inhibitor of metalloproteinases-3 (TIMP3) gene. The known mutations introduce potentially unpaired cysteine residues in the C terminus of the protein and result in the formation of higher-molecular-weight protein complexes of as yet unknown composition and functional consequences in the pathologic course of SFD. To facilitate in vivo investigation of mutant TIMP3, the authors generated a knock-in mouse carrying a disease-related Ser156Cys mutation in the orthologous murine Timp3 gene. methods. Site-directed mutagenesis and homologous recombination in embryonic stem (ES) cells was used to generate mutant ES cells carrying the Timp3 S156C allele. Chimeric animals were obtained, of which two displayed germline transmission of the mutated allele. Molecular genetic, biochemical, electron microscopic, and electrodiagnostic techniques were used for characterization. results. At 8 months of age, knock-in mice showed abnormalities in the inner aspect of Bruch’s membrane and in the organization of the adjacent basal microvilli of the retinal pigment epithelium (RPE). Changes resembling those in the mutant animals were also present to some extent in normal littermates, but only at an advanced age of 30 months. Long-term electrodiagnostic recordings indicated normal retinal function throughout life. The biochemical characteristics of the mutant protein appear similar in humans and knock-in mice, suggesting common molecular pathways in the two species. The localization of the mutant protein in the eye is normal, although there is evidence of increased Timp3 levels in Bruch’s membrane of mutant animals. conclusions. The knock-in mice display early features of age-related changes in Bruch’s membrane and the RPE that may represent the primary clinical manifestations of SFD. In addition, our immunolabeling studies and biochemical data support a model proposing that site-specific excess rather than absence or deficiency of functional Timp3 may be the primary consequence of the known Timp3 mutations

    Branch Retinal Vein Occlusion: Pathogenesis, Visual Prognosis, and Treatment Modalities

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    In branch retinal vein occlusion (BRVO), abnormal arteriovenous crossing with vein compression, degenerative changes of the vessel wall and abnormal hematological factors constitute the primary mechanism of vessel occlusion. In general, BRVO has a good prognosis: 50–60% of eyes are reported to have a final visual acuity (VA) of 20/40 or better even without treatment. One important prognostic factor for final VA appears to be the initial VA. Grid laser photocoagulation is an established treatment for macular edema in a particular group of patients with BRVO, while promising results for this condition are shown by intravitreal application of steroids or new vascular endothelial growth factor inhibitors. Vitrectomy with or without arteriovenous sheathotomy combined with removal of the internal limiting membrane may improve vision in eyes with macular edema which are unresponsive to or ineligible for laser treatment

    Integrating High-Content Imaging and Chemical Genetics to Probe Host Cellular Pathways Critical for <em>Yersinia Pestis</em> Infection

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    <div><p>The molecular machinery that regulates the entry and survival of <em>Yersinia pestis</em> in host macrophages is poorly understood. Here, we report the development of automated high-content imaging assays to quantitate the internalization of virulent <em>Y. pestis</em> CO92 by macrophages and the subsequent activation of host NF-κB. Implementation of these assays in a focused chemical screen identified kinase inhibitors that inhibited both of these processes. Rac-2-ethoxy-3 octadecanamido-1-propylphosphocholine (a protein Kinase C inhibitor), wortmannin (a PI3K inhibitor), and parthenolide (an IκB kinase inhibitor), inhibited pathogen-induced NF-κB activation and reduced bacterial entry and survival within macrophages. Parthenolide inhibited NF-κB activation in response to stimulation with Pam3CSK4 (a TLR2 agonist), <em>E. coli</em> LPS (a TLR4 agonist) or <em>Y. pestis</em> infection, while the PI3K and PKC inhibitors were selective only for <em>Y. pestis</em> infection. Together, our results suggest that phagocytosis is the major stimulus for NF-κB activation in response to <em>Y. pestis</em> infection, and that <em>Y. pestis</em> entry into macrophages may involve the participation of protein kinases such as PI3K and PKC. More importantly, the automated image-based screening platform described here can be applied to the study of other bacteria in general and, in combination with chemical genetic screening, can be used to identify host cell functions facilitating the identification of novel antibacterial therapeutics.</p> </div
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