Development of a dual hybrid AAV vector for endothelial-targeted expression of von Willebrand factor
Authors: Aboud Sakkal
Elena Barbon
Cécile V Denis
Caterina Casari
Solenne Marmier
Charlotte Kawecki
Severine Charles
Peter J Lenting
Federico Mingozzi
Olivier D Christophe
Fanny Collaud
Giuseppe Ronzitti
Journal: Gene Therapy (2021)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Von Willebrand disease; gene therapy; endothelial cells; VWF; AAV vector
Affiliations: Généthon, 91000, Evry, France., Laboratory of Hemostasis, Inflammation and Thrombosis, Institut National de la Santé et de la Recherche Médicale UMR_1176, Université Paris-Saclay, 94276, Le Kremlin-Bicêtre, France., Généthon, 91000, Evry, France. .

Abstract:  Von Willebrand disease (VWD), the most common inherited bleeding disorder in humans, is caused by quantitative or qualitative defects in von Willebrand factor (VWF). VWD represents a potential target for gene therapy applications, as a single treatment could potentially result in a long-term correction of the disease. In recent years, several liver-directed gene therapy approaches have been exploited for VWD, but their efficacy was generally limited by the large size of the VWF transgene and the reduced hemostatic activity of the protein produced from hepatocytes. In this context, we aimed at developing a gene therapy strategy for gene delivery into endothelial cells, the natural site of biosynthesis of VWF. We optimized an endothelial-specific dual hybrid AAV vector, in which the large VWF cDNA was put under the control of an endothelial promoter and correctly reconstituted upon cell transduction by a combination of trans-splicing and homologous recombination mechanisms. In addition, we modified the AAV vector capsid by introducing an endothelial-targeting peptide to improve the efficiency for endothelial-directed gene transfer. This vector platform allowed the reconstitution of full-length VWF transgene both in vitro in human umbilical vein endothelial cells and in vivo in VWD mice, resulting in long-term expression of VWF. 

Retracted: No

PubPeer comments:
 Figure 1 and Supplementary Figure 2 contain the same Ponceau sections, but they don t seem to be labelled consistently, I ve added the coloured shapes to show where I mean. Have I misunderstood something here? Would the authors please comment? ![file] , 
 Dear Mycosphaerella arachidis, thank you for carefully reading the paper. As a control for sample loading on the gel, we labelled some Ponceau stained proteins. For Huh7 cells, we highlighted a 70kDa protein while for HEK293 a slightly heavier protein (the one you highlighted in red) since the two protein petterns were obviously different among the two cell types. You re right, there is a mistake in the lower panel of the supplementary Figure2, since it reports the same Ponceau as Figure 1, but indeed these are only Huh7 cells. I hope I answered your question. , 
 #2 Hi Elena, thank you for the prompt response confirming the error. What do the authors think the best course of action is? I think it might be helpful to post the correct loading controls, and share the images before they were cropped. Since the figures cannot currently be interpreted by readers of your paper, perhaps a correction is appropriate. Is a ladder normally visible on developed western blot? I haven t used this technique much. ,