AAV2-or AAVv66-vector was incubated for 30?min at 37?C in the presence of increasing quantities of heparin (Sigma-Aldrich, H3149-25KU) in 10% FBS in DMEM (Existence Technologies, 11965126)
April 22, 2022
AAV2-or AAVv66-vector was incubated for 30?min at 37?C in the presence of increasing quantities of heparin (Sigma-Aldrich, H3149-25KU) in 10% FBS in DMEM (Existence Technologies, 11965126). Here, we describe a novel capsid identified inside a human being clinical sample by high-throughput, long-read sequencing. The capsid, which we have named AAVv66, shares high sequence similarity with AAV2. We demonstrate that compared to AAV2, AAVv66 exhibits enhanced production yields, virion stability, and CNS transduction. Unique structural properties of AAVv66 visualized by cryo-EM at 2.5-? resolution, suggest that essential residues in the three-fold protrusion and at the interface of the five-fold axis of symmetry likely contribute to the beneficial characteristics of AAVv66. Our findings underscore the potential of AAVv66 like a gene therapy vector. gene encodes for three capsid subunits, VP1CVP3 that assemble into a ORF. Amplicons were subjected to solitary molecule, real-time (SMRT) sequencing and the producing reads were analyzed by BWA-MEM positioning to contemporary AAV serotype sequences, InDelFixer to remove insertion/deletions related to PCR or SMRT sequencing errors, and de novo assembly to cluster reads of high sequence similarity. b The sequence of variant AAVv66 was found to become the most abundant in the analysis (45%). c Summary of the 13 unique residues in the AAVv66 capsid sequence that are different from AAV2. d Phylogenetic tree of AAV2 variants reported with this study (blue) and contemporary serotypes. To better make predictions for the contributions of the unique AAVv66 amino acid residues toward capsid function, the VP3 region was compared with those of additional contemporary AAV serotypes (AAV1CAAV9). The most notable differences happen at four positions (499, 533, 585, and 588), which are highly conserved among AAV serotypes (Supplementary Fig.?1b). At position 499, most serotypes harbor an asparagine, while AAVv66, AAV2, AAV4, and AAV9 have a negatively charged aspartic Hydrochlorothiazide acid or glutamic acid. The highly conserved phenylalanine at position 533 is definitely a tyrosine in AAVv66 (also, T533 in AAV5). Finally, unlike AAV2, which harbors positively charged arginine residues that define AAV2s capacity to bind heparan sulfate proteoglycans (HSPG) at positions 585 and 58811, AAVv66 consists of S585 and T588 (identical to AAV1, AAV3, AAV5, and AAV6). AAVv66 and AAV2 differ in production and cell infectivity The strong affinity of AAV2 for heparin and its producing strong cellCsurface association is definitely proposed to lead to the virus relatively poor packaging titers24. The limited vector yield by AAV2 is definitely thought to result from non-productive binding and re-infection of the packaging cells by vector particles during Hydrochlorothiazide production. We consequently wanted to compare vector production and cell infectivity of AAVv66 with those of AAV2 and AAV3b. Of notice, AAV3b is Hydrochlorothiazide the closest unique cousin of AAV2 (89% sequence similarity), but uses different electrostatic surface charges in the threefold protrusions to weakly bind heparin25. This difference between AAV3b and AAV2 likely explains AAV3bs improved packaging titers FLN that result from weaker transduction of HEK maker cells during production26,27. We 1st compared the packaging profiles of AAVv66 with those of AAV2 and AAV3b by measuring the yields of encapsidated vector genomes in cell lysates. To this end, the AAVv66 capsid ORF was synthesized and cloned into a plasmid expressing AAV2 under the AAV2 promoter (pAAV2/v66). Small-scale vector preparations of AAVv66, AAV2, and AAV3b were used to package Hydrochlorothiazide a single-stranded vector consisting of the firefly luciferase transgene driven from the ubiquitous chicken-beta actin promoter (AAV-transgene driven from the CB6 promoter28. Vectors were unilaterally injected into the right hemisphere of the hippocampus at a dose of 3.6E9 vector genomes (vg) per animal. Four weeks post-injection, cryo-sections of treated brains showed that AAVv66 transduced ~13-collapse more cells of the CNS than AAV2, as Hydrochlorothiazide shown by the enhanced spread throughout the cells, while AAV2 tended to stay localized to the site of injection (Fig.?2a, b). High-magnification imaging of contralateral areas to the site of injection showed that all sub-anatomical regions of the brain (cornu ammonis [CA1CCA4], dentate gyrus, and corpus callosum, Fig.?2c), exhibited detectable levels of EGFP expression (Fig.?2d), indicating.