Abstract
Abstract: :
Purpose:To determine the effect and mechanism of hyaluronan modulation of adenoviral transgene expression Methods:Cells were transduced using adenoviral vectors containing expression constructs for firefly luciferase in the presence or absence hyaluronan. The time-dependence of enhancement was established by varying the time that the cells were incubated with hyaluronan after adenoviral exposure. The effect of digesting the hyaluronan with lyase was determined. Results:The enhancement of transgene expression by high molecular weight (MW) hyaluronan was time-dependent and indicated a critical time period of 4-6 hours after adenoviral exposure. High MW hyaluronan was found to enhance adenoviral transgene expression by 1-2 orders of magnitude. Lyase digestion of the hyaluronan not only abrogated the enhancement but actually blocked adenoviral transgene expression. Hyaluronan had no effect on adenoviral-mediated transgene expression in Jurkat cells, a human cell line that contains the adenoviral receptor CAR but not αvß5, an integrin that mediates adenoviral internalization, or CD44, a hyaluronan receptor. When a stable Jurkat cell line expressing CD44 was produced, hyaluronan was found to enhance transgene expression. An antibody that specifically blocks hyaluronan binding to CD44 inhibited transgene expression in murine EpH4 cells that express CD44. Conclusion:Hyaluronan, a macropolysaccharide, is a major component of vitreous and enhances adenoviral-mediated transgene expression through an interaction with its receptor, CD44. The time-dependence of enhanced transgene expression suggests that hyaluronan must be present after adenoviral internalization but prior to transcription of viral DNA. The molecular weight of the polysaccharide is critical; high molecular weight hyaluronan enhances and low molecular weight hyaluronan inhibits adenoviral transgene expression. These results may have implications not only for enhancing gene therapy applications using adenoviral vectors but also for inhibiting adenovirus infections.
Keywords: 419 gene transfer/gene therapy • 307 adenovirus • 629 vitreous