Abstract The transplantation of pigment epithelial cells as a therapeutic modality for retinal degeneration requires that the transplanted cells form a monolayer in the subretinal space that will ...establish communication with photoreceptors. Since previous studies have shown that transplanted cells in suspension do not form a monolayer, it will be necessary to transplant preformed pigment epithelial cell monolayers at the location of the exposed photoreceptors. To establish cell monolayers, retinal pigment epithelial (RPE) cells were cultured on ultrathin collagen membranes. Cells were examined for morphology, for characteristics of differentiation and viability. Membrane degradation and long-term biocompatibility in vivo were assessed following subconjunctival and subretinal implantation in rabbits. These studies have shown that RPE cells adhere, proliferate, form monolayers, and acquire differentiated properties on a collagen membrane that has features similar to Bruch's membrane. Membranes transplanted subconjunctivally and subretinally exhibit excellent biocompatibility without any evidence of inflammation or rejection. RPE cells cultured on collagen membranes acquire differentiated characteristics similar to those of RPE cells in vivo and form complete monolayers that are amenable to be transplanted to the subretinal space. The collagen membranes are non-toxic and do not elicit any rejection or inflammatory response when implanted subconjunctivally or subretinally in rabbits.
CD73 (ecto-5'-nucleotidase) is expressed by a broad range of immune cells and attenuates inflammation in several acute disease models. This study therefore explored the role of CD73-derived adenosine ...in a model of chronic vascular inflammation such as atherogenesis.
CD73(-/-) mice were backcrossed into the apolipoprotein E (ApoE(-/-)) background. In CD73(-/-)/ApoE(-/-) double mutants, atherosclerotic lesion formation was increased by ∼50% compared with ApoE(-/-). However, the cellular composition and extracellular matrix of the plaques did not differ. Surprisingly, we found significant activity and expression of CD73 in the plaque of ApoE(-/-) mice which increased over time. CD73 co-localized with macrophages, Tregs, and cells of mesenchymal origin. Genome-wide microarray analysis of the aorta lacking CD73 revealed upregulation of endothelin-1 (Edn1) mRNA together with changes of genes in lipid metabolism and the Wnt and nuclear factor kappa B pathways. Measurement of plasma levels verified the upregulation of Edn1 in CD73(-/-) and double mutants. Plasma triglycerides (TG) were also found to be significantly elevated in the CD73(-/-)/ApoE(-/-) mice compared with ApoE(-/-) controls.
Lack of CD73 promotes atherogenesis most likely by de-inhibition of resident macrophages and T cells. Elevated Edn1 and TG levels may have contributed. This establishes CD73-derived adenosine as a direct or indirect regulator of atherogenesis.
Aims
CD73 (ecto-5′-nucleotidase) is expressed by a broad range of immune cells and attenuates inflammation in several acute disease models. This study therefore explored the role of CD73-derived ...adenosine in a model of chronic vascular inflammation such as atherogenesis.
Methods and results
CD73−/− mice were backcrossed into the apolipoprotein E (ApoE−/−) background. In CD73−/−/ApoE−/− double mutants, atherosclerotic lesion formation was increased by ∼50% compared with ApoE−/−. However, the cellular composition and extracellular matrix of the plaques did not differ. Surprisingly, we found significant activity and expression of CD73 in the plaque of ApoE−/− mice which increased over time. CD73 co-localized with macrophages, Tregs, and cells of mesenchymal origin. Genome-wide microarray analysis of the aorta lacking CD73 revealed upregulation of endothelin-1 (Edn1) mRNA together with changes of genes in lipid metabolism and the Wnt and nuclear factor kappa B pathways. Measurement of plasma levels verified the upregulation of Edn1 in CD73−/− and double mutants. Plasma triglycerides (TG) were also found to be significantly elevated in the CD73−/−/ApoE−/− mice compared with ApoE−/− controls.
Conclusion
Lack of CD73 promotes atherogenesis most likely by de-inhibition of resident macrophages and T cells. Elevated Edn1 and TG levels may have contributed. This establishes CD73-derived adenosine as a direct or indirect regulator of atherogenesis.
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