AbstractsBiology & Animal Science

Gene therapy involves the delivery of exogenous DNA into the target cells in order to produce therapeutic protein or to correct a genetic defect. The use of cationic liposomes and polymers as carriers of DNA is based on observations that positively charged carriers bind to anionic DNA protecting its premature degradation and facilitating its cellular uptake in transfection. The modification of carriers and the engineering of DNA are proposed to enable efficient and prolonged protein expression after transfection. Gene therapy is a potential treatment for age related macular degeneration (AMD). The dysfunction of retinal pigment epithelial (RPE) cells is assumed to be a significant factor in the development of AMD. The aim of this Master’s thesis was to study non-viral gene delivery to RPE cells and endothelial cells using several carrier/DNA combinations. Carriers in this study were DOTAP/DOPE/PS liposomes, methacrylamide based (PDMAEMA) micelles, and anionic lipid coated DNA complexes (LCDCs). The carriers were complexed with episomal plasmid DNA or minicircles using secreted alkaline phosphatase (SEAP) gene as a marker gene. Adult retinal pigment epithelial (ARPE-19) cells, human embryonic stem cell-derived retinal pigment epithelial cells (hESC-RPE), human embryonic primary RPE cells and endothelial cells (EaHy 926) were used in transfections. In ARPE-19 cells linear PBuA-PDMAEMA -based complexes reached the transfection efficiency of positive control whereas in human primary RPE cells star-like PBuAPDMAEMA -based complexes were the most efficient. In human primary RPE cells, SEAP secretion lasted at least 18 days when PDMAEMA-based micelles complexed with plasmid or minicircle with cytomegalovirus (CMV) promoter were used. High nitrogen/phosphate (n/p) ratios of polyplexes decreased cell viability. DOTAP/DOPE/PS/DNA lipoplexes transfected EaHy cells with high efficiency. In hESC-RPE, lipoplexes also exceeded the transfection efficiency of the positive control and the marker protein secretion lasted ~20 days. Human elongation factor 1a (EF1a) promoter could not prevent transgene silencing. Gene delivery did not succeed with LCDCs in any transfection. According to the results, PBuA-PDMAEMA-polymers and DOTAP/DOPE/PS-liposomes complexed with episomal plasmid or minicircles are potential gene delivery agents for further studies in AMD. More investigation is needed i.e. to confirm the transfection efficiency of the complexes in non-dividing cells. Geeniterapian tarkoituksena on siirtää kohdesoluihin vierasta DNA:ta tuottamaan terapeuttista proteiinia tai korjaamaan geenivirhe. Positiivisesti varautuneiden lipidi- ja polymeerikantaja-aineiden on todettu muodostavan komplekseja negatiivisesti varautuneen DNA:n kanssa suojellen DNA:ta ennenaikaiselta hajoamiselta ja parantavan DNA:n soluunottoa geeninsiirrossa. Kantajamolekyylien kehittäminen ja DNA:n muokkaaminen voivat mahdollistaa pitkäkestoinen proteiinin tuotannon kohdesoluissa. Geeniterapia on mahdollinen tulevaisuuden hoitomuoto silmänpohjan ikärappeumaan,…