Liposome-based DNA carriers may induce cellular stress response and change gene expression pattern in transfected cells

<p>Abstract</p> <p>Background</p> <p>During functional studies on the rat stress-inducible <it>Hspa1b </it>(<it>hsp70.1</it>) gene we noticed that some liposome-based DNA carriers, which are used for transfection, induce its promoter activity. This observation concerned commercial liposome formulations (LA), Lipofectin and Lipofectamine 2000. This work was aimed to understand better the mechanism of this phenomenon and its potential biological and practical consequences.</p> <p>Results</p> <p>We found that a reporter gene driven by <it>Hspa1b </it>promoter is activated both in the case of transient transfections and in the stably transfected cells treated with LA. Using several deletion clones containing different fragments of <it>Hspa1b </it>promoter, we found that the regulatory elements responsible for most efficient LA-driven inducibility were located between nucleotides -269 and +85, relative to the transcription start site. Further studies showed that the induction mechanism was independent of the classical HSE-HSF interaction that is responsible for gene activation during heat stress. Using DNA microarrays we also detected significant activation of the endogenous <it>Hspa1b </it>gene in cells treated with Lipofectamine 2000. Several other stress genes were also induced, along with numerous genes involved in cellular metabolism, cell cycle control and pro-apoptotic pathways.</p> <p>Conclusions</p> <p>Our observations suggest that i) some cationic liposomes may not be suitable for functional studies on <it>hsp </it>promoters, ii) lipofection may cause unintended changes in global gene expression in the transfected cells.</p

Results of the clinical donor case and quality system case workshops of the European Association of Tissue Banks annual meeting 2009

The European Association of Tissue Banks (EATB) Donor Case Workshop and Quality System Case workshop are forums held within the program of the EATB Annual Congress. These workshops offer an opportunity to discuss and evaluate approaches taken to challenging situations, regarding donor selection and quality issues, and strengthen the professional tissue banking and regulatory networks across Europe. This report reflects some of the discussion at the congress workshops and also subsequent correspondence between the various individuals who submitted cases for discussion. The cases presented to the workshops demonstrate that the findings, their interpretation, deducted actions and preventive measures in tissue banks are not predictable. The varied responses and lack of consensus corroborate this and clearly indicate that operating procedures cannot comprehensively cover or prepare for all eventualities. For many of the issues raised there is a lack of information in the published literature. The workshops actively engage participants, representing a wide array of international expertise, in an informal, secure and enjoyable setting, which facilitates learning from peers and provides potential solutions to those submitting cases. By publishing a summary of the discussions, we hope to reach a wider audience and to stimulate individuals to undertake full literature reviews or research on some of the discussed subjects