Characterization of the expression of key adenoviral receptors CAR and integrin beta3/beta5 subunits on the membrane of human NT2 neurons.

Expression of therapeutic gene products in differentiated human NT2 neurons (NT2/Ns) is being explored for ex vivo gene therapy of human neurological diseases. In this study we determined the efficiency of adenovirus (Ad)-mediated gene delivery into NT2/Ns and characterized the expression of several key receptors known to be required for efficient Ad-mediated gene delivery. Undifferentiated NT2 cells and NT2/Ns were infected by Ad expressing green fluorescent protein at an efficiency of 33% and 17%, respectively percentages much lower than the 92% infectivity obtained from a human non-neuronal cell line A549 cells. This relatively low infectivity of NT2/Ns might be caused by the extremely low expression of integrin subunit beta3 and the reduced expression of beta5 during differentiation. The expression of coxsackie-Ad receptor (CAR) was relatively high and remained constant during differentiation. Blocking CAR receptor using an antibody specific against CAR reduced Ad infectivity in a dose-dependent manner. These observations suggest that modulating the expression of integrin subunits beta3/5 or the functional heterodimer alphavbeta3/5 in human NT2/Ns may enhance adenoviral infectivity of NT2/Ns.