Impact of Heparan Sulfate Binding on Transduction of Retina by Recombinant Adeno-Associated Virus Vectors. J Virol 2016 Apr;90(8):4215-4231
Date
02/13/2016Pubmed ID
26865709Pubmed Central ID
PMC4810560DOI
10.1128/JVI.00200-16Scopus ID
2-s2.0-84963826914 (requires institutional sign-in at Scopus site) 55 CitationsAbstract
UNLABELLED: Adeno-associated viruses (AAVs) currently are being developed to efficiently transduce the retina following noninvasive, intravitreal (Ivt) injection. However, a major barrier encountered by intravitreally delivered AAVs is the inner limiting membrane (ILM), a basement membrane rich in heparan sulfate (HS) proteoglycan. The goal of this study was to determine the impact of HS binding on retinal transduction by Ivt-delivered AAVs. The heparin affinities of AAV2-based tyrosine-to-phenylalanine (Y-F) and threonine-to-valine (T-V) capsid mutants, designed to avoid proteasomal degradation during cellular trafficking, were established. In addition, the impact of grafting HS binding residues onto AAV1, AAV5, and AAV8(Y733F) as well as ablation of HS binding by AAV2-based vectors on retinal transduction was investigated. Finally, the potential relationship between thermal stability of AAV2-based capsids and Ivt-mediated transduction was explored. The results show that the Y-F and T-V AAV2 capsid mutants bind heparin but with slightly reduced affinity relative to that of AAV2. The grafting of HS binding increased Ivt transduction by AAV1 but not by AAV5 or AAV8(Y733F). The substitution of any canonical HS binding residues ablated Ivt-mediated transduction by AAV2-based vectors. However, these same HS variant vectors displayed efficient retinal transduction when delivered subretinally. Notably, a variant devoid of canonical HS binding residues, AAV2(4pMut)ΔHS, was remarkably efficient at transducing photoreceptors. The disparate AAV phenotypes indicate that HS binding, while critical for AAV2-based vectors, is not the sole determinant for transduction via the Ivt route. Finally, Y-F and T-V mutations alter capsid stability, with a potential relationship existing between stability and improvements in retinal transduction by Ivt injection.
IMPORTANCE: AAV has emerged as the vector of choice for gene delivery to the retina, with attention focused on developing vectors that can mediate transduction following noninvasive, intravitreal injection. HS binding has been postulated to play a role in intravitreally mediated transduction of retina. Our evaluation of the HS binding of AAV2-based variants and other AAV serotype vectors and the correlation of this property with transduction points to HS affinity as a factor controlling retinal transduction following Ivt delivery. However, HS binding is not the only requirement for improved Ivt-mediated transduction. We show that AAV2-based vectors lacking heparin binding transduce retina by subretinal injection and display a remarkable ability to transduce photoreceptors, indicating that other receptors are involved in this phenotype.
Author List
Boye SL, Bennett A, Scalabrino ML, McCullough KT, Van Vliet K, Choudhury S, Ruan Q, Peterson J, Agbandje-McKenna M, Boye SEAuthor
Miranda L. Scalabrino PhD Assistant Professor in the Ophthalmology and Visual Sciences department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsCapsid
Dependovirus
Genetic Vectors
HEK293 Cells
Heparitin Sulfate
Humans
Injections, Intraocular
Injections, Intravenous
Liver
Mice, Inbred BALB C
Mice, Inbred C57BL
Mutation
Photoreceptor Cells, Vertebrate
Reassortant Viruses
Retina
Transduction, Genetic
Vitreous Body
