Improved cardiac gene transfer by transcriptional and transductional targeting of adeno-associated viral vectors

Abstract Objective: Vectors based on recombinant adeno-associated virus 2 (AAV-2) are a promising tool for cardiac gene transfer. However, potential therapeutic applications need to consider the predominant transduction of the liver once AAV-2 vectors enter the systemic circulation. We therefore aimed to increase efficiency and specificity of cardiac vector delivery by combining transcriptional and cell surface targeting. Methods: For analysis of transcriptional targeting, recombinant AAV vectors were generated harboring a luciferase reporter gene under control of the cytomegalovirus (CMV) promoter or the 1.5-kb cardiac myosin light chain promoter fused to the CMV immediate-early enhancer (CMV enh /MLC1.5). Luciferase activities were determined in representative organs three weeks after intravenous injection of the vector into adult mice. Transductional targeting was studied using luciferase-reporter constructs crosspackaged into capsids of AAV serotypes 1 to 6 and modified AAV-2 capsids devoid of binding their primary receptor heparan sulfate proteoglycan. Results: Intravenous injections of AAV-2 vectors harboring the CMV enh /MLC1.5 promoter enabled a specific and 50-fold higher reporter gene expression in left ventricular myocardium of adult mice compared to vectors containing the CMV promoter. Comparison of AAV-2 vector genomes crosspackaged into capsids of AAV-1 to -6 showed that AAV-1, -4, -5, and -6 capsids increased cardiac transduction efficiency by about 10-fold. However, transduction of other organs such as the liver was also increased after systemic administration. In contrast, AAV-2-based vectors with ablated binding to their primary receptor heparan sulfate proteoglycan enabled a significantly increased efficiency of cardiac gene transfer and reduced transduction of the liver. Conclusions: Combining transcriptional targeting by the CMV enh /MLC1.5 promoter and AAV vectors devoid of binding the AAV-2 primary receptor results in an efficient cardiac gene transfer with a significantly reduced hepatic transduction

Middle East - North Africa and the millennium development goals : implications for German development cooperation

          Closed-loop controlled combustion is a promising technique to improve the overall performance of internal combustion engines and Diesel engines in particular. In order for this technique to be implemented some form of feedback from the combustion process is required. The feedback signal is processed and from it combustionrelated parameters are computed. These parameters are then fed to a control process which drives a series of outputs (e.g. injection timing in Diesel engines) to control their values. This paper’s focus lies on the processing and computation that is needed on the feedback signal before this is ready to be fed to the control process as well as on the electronics necessary to support it. A number of feedback alternatives are briefly discussed and for one of them, the in-cylinder pressure sensor, the CA50 (crank angle in which the integrated heat release curve reaches its 50% value) and the IMEP (Indicated Mean Effective Pressure) are identified as two potential control variables. The hardware architecture of a system capable of calculating both of them on-line is proposed and necessary feasibility size and speed considerations are made by implementing critical blocks in VHDL targeting a flash-based Actel ProASIC3 automotive-grade FPGA