UNCORRECTED PROOFS jgm521 THE JOURNAL OF GENE MEDICINE RESEARCH ARTICLE J Gene Med 2004; 6: 000–000. Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jgm.521 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 Adenovirus vectors targeting α V integrin or heparan sulfate receptors display different distribution of transgene activity after intramuscular injection Corrado Cirielli, 1,3†, * Francesco Serino, 1† Stefania Straino, 2† Gabriele Toietta, 3 Damiano Abeni, 4 Giorgio Ventoruzzo, 3 Giuseppe Orlando, 3 Paola Mazzanti, 3 Guido Melillo, 3 Thomas J. Whickham, 5 Imre Kovesdi, 5 Paolo Biglioli, 2 Carlo Gaetano, 3 Maurizio C. Capogrossi 3 1 Department of Vascular Surgery and Pathology, Istituto Dermopatico dell’Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico IDI-IRCCS, Rome, Italy 2 Istituto Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy 3 Laboratory of Vascular Pathology, Istituto Dermopatico dell’Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico IDI-IRCCS, Rome, Italy 4 Service of Epidemiology, Istituto Dermopatico dell’Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico IDI-IRCCS, Rome, Italy 5 GenVec Inc., Rockville, Maryland, USA *Correspondence to: Corrado Cirielli, Department of Vascular Surgery and Pathology and Laboratory of Vascular Pathology, Istituto Dermopatico dell’Immacolata Istituto di Ricovero e Cura a Carattere Scientifico, Via dei Monti di Creta 104, 00167 Rome, Italy. E-mail: c.cirielli@idi.it † These authors contributed equally to this work. Received: 24 June 2002 Revised: 3 October 2003 Accepted: 24 October 2003 Abstract Background Modification of the fiber proteins in replication-deficient adenoviral (Ad) vectors through incorporation of specific receptor-binding motifs may represent a strategy to enhance their tissue targeting capabilities. Methods In this study, we compared an unmodified Ad (GV10) with two mutated vectors obtained by insertion of specific target sequences that redirect binding, either toward α V integrin (RGD) or heparan sulfate (UTV) cellular receptors, for reporter gene expression spatial distribution in the rabbit skeletal muscle. In a first series of experiments, injection volume was kept constant and activity of a lacZ transgene was evaluated 48 h after injection of the Ad vectors at different doses. In separate experiments, the effects of different volumes of injection at a constant dose of Ad vector were monitored. Results All vectors evaluated showed a significant increase in the number of lacZ-positive muscle segments, with increasing vector dose. However, in muscles treated with the UTV vector, fewer muscle fibers were β -gal- positive than in GV10 or RGD vector treated animals. In fact, total β -gal activity increased in a dose-dependent fashion in the GV10- and RGD-treated muscles, but not in the UTV-treated ones. Remarkably, in samples from UTV- treated animals, a volume-dependent enhancement of transgene expression was observed during experiments performed at the same dose and different injection volumes. Conclusions The results of the present study demonstrate that altering Ad affinity for cellular receptors modulates the level and distribution of transgene activity, conferring characteristics that may allow for treatment customization. Copyright  2004 John Wiley & Sons, Ltd. Keywords adenovirus; gene therapy; skeletal muscle; integrins; heparan sulfate receptor Introduction Replication-deficient adenoviral (Ad) vectors have been largely employed in experimental and clinical applications for cardiovascular gene ther- apy [1–6]. The results of the phase I clinical trials showed that direct myocardial administration of recombinant Ad vectors encoding vascular endothelial growth factor (VEGF) to individuals with clinically significant coronary artery disease is well tolerated, thus encouraging initiation of phase II studies [7]. Therapeutic angiogenesis has also been suggested for the 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 Copyright  2004 John Wiley & Sons, Ltd.