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Sinn, P.

Publications and source records attributed to Sinn, P..

3 recordsLinked to original sources

Optimized AAV capsids robustly transduce airway epithelial cells

Gene therapies have demonstrated transformative potential for a range of genetic disorders, including immunodeficiencies, hematopoietic conditions, and neuromuscular diseases. However, the application of these approaches to cystic fibrosis (CF) and other airway diseases remains constrained by the challenge of efficient gene delivery to target epithelial cells. Adeno-associated virus (AAV) vectors are widely used for in vivo gene delivery due to their favorable safety profile and capacity for long-term transgene expression in non-dividing cells. Nonetheless, current AAV capsids require high doses to achieve therapeutic efficacy in the airways, raising safety concerns. Here we report the development of novel AAV capsid variants with markedly enhanced transduction efficiency of airway epithelial cells. Using unbiased peptide-modified AAV libraries and round-over-round screening in well-differentiated primary cultures of human airway epithelia (HAE), we identified 20 novel capsids that efficiently transduced cells at doses 10- to 100-fold lower than those required by existing vectors (termed AAV-AE). These variants demonstrated high transgene expression in HAE, primary human basal cells, tracheal explants from nonhuman primates, and murine airways in vivo. These optimized AAV capsids represent a significant advancement in pulmonary gene therapy, offering a versatile platform for the delivery of gene addition and editing reagents to treat CF and other respiratory diseases.

molecular biology↗

Lentiviral-mediated gene complementation rescues pathogenic ABCA3 variants

The ATP-binding cassette subfamily A member 3 (ABCA3) protein on the limiting membrane of lamellar bodies in alveolar type 2 (AT2) cells transports phospholipids required for pulmonary surfactant assembly. ABCA3 deficiency results from biallelic pathogenic variants in ABCA3 and causes progressive neonatal respiratory failure or childhood interstitial lung disease (chILD). Supportive/compassionate care or lung transplantation are the only current definitive treatments for ABCA3 deficiency and progressive respiratory failure. Complementing dysfunctional ABCA3 by gene addition has therapeutic potential. Previous studies show that repairing or complementing ABCA3 in induced pluripotent stem cell (iPSC)-derived AT2 cells rescues lamellar body morphology and surfactant phospholipid composition. Pathogenic variants disrupt ABCA3 function through altered protein trafficking (type 1) or by impaired phospholipid transport (type 2) into lamellar bodies. Here we tested ABCA3 gene complementation using a human pulmonary epithelial cell line (A549) with a genomically silenced ABCA3 locus (ABCA3KO). From this line, additional cell lines that stably express individual ABCA3 variant cDNA constructs from a single genomic locus were tested: L101P (type 1), E292V (type 2), E690K (type 2), or wild-type ABCA3. Lentiviral-mediated ABCA3 delivery to each cell line partially rescued localization to LAMP3+ vesicles, lamellar body-like structure morphology, and cell proliferation. A functional assay measuring NF-{kappa}B signaling suggested that ABCA3 complementation ameliorated aberrant inflammatory signaling in E292V or E690K (type 2) mutant lines, but not in L101P (type 1) or knockout lines. These studies highlight the therapeutic potential of gene addition as well as differences between ABCA3 pathogenic variants that may influence genetic therapy outcomes.

molecular biology↗

Methods Matter -- Standard Production Platforms For Recombinant AAV Can Produce Chemically And Functionally Distinct Vectors

Different manufacturing approaches have been used in the production of recombinant adeno-associated virus (rAAV). The two leading approaches are transiently transfected human HEK293 cells and live baculovirus infection of Sf9 insect cells. Unexplained differences in vector performance have been seen clinically and preclinically. Thus, we performed for the first time a highly controlled comparative production analysis varying only the host cell species but keeping all other rAAV production parameters the same. We demonstrate that host cell species is critical for determining vector potency. Given these key findings, we then sought to deeply characterize differences in rAAVs when produced by these two manufacturing platforms with multiple analytical approaches including: proteomic profiling by mass spectrometry, isoelectric focusing, cryo-EM, denaturation assays, genomic and epigenomic sequencing of packaged genomes, human cytokine profiling, and comparative functional transduction assessments in vitro and in vivo, including in humanized liver mice. Using these tools weve made two major discoveries: 1) rAAV capsids have post-translational modifications (PTMs) including glycosylation, acetylation, phosphorylation, methylation and deamidation, and these PTMs differ between platforms; 2) rAAV genomes are methylated during production, and these methylation marks are also differentially deposited between platforms. In addition, our data also demonstrate that host cell protein impurities differ between platforms and can have their own PTMs including potentially immunogenic N-linked glycans. We show that human-produced rAAVs are more potent than baculovirus-Sf9 vectors in various cell types in vitro (P < 0.05-0.0001), in various mouse tissues in vivo (P < 0.03-0.0001), and in human liver in vivo (P < 0.005). Collectively, our findings were reproducible across vendors, including commercial manufacturers, academic core facilities, and individual laboratory preparations. These vector differences may have clinical implications for rAAV receptor binding, trafficking, expression kinetics, expression durability, vector immunogenicity as well as cost considerations.

molecular biology↗