{"doi":"10.1002/ejhf.2792","title":"Abstract","abstract":"Background: Cardiac remodelling processes are closely associated with fibrosis, a pathological mechanism leading to the stiffening of the myocardium and therefore, to a deteriorating heart function.Therapeutic strategies are urgently required since current treatments are not addressing the critical over-activation of fibroblasts that contributes to the progression to heart failure.We developed a novel gene therapy approach based on adeno-associated viral (AAV) vectors to specifically target these disease-associated fibroblasts and identified three promising AAV variants with an improved tropism for cardiac fibroblasts.Purpose: Adeno-associated viruses present optimal features for a long-term gene delivery in vivo.Their safety and efficacy has already been demonstrated in diverse clinical trials that resulted in five market approvals in Europe to date.However, the available serotypes are not suitable for the targeting of cardiac fibroblasts.Thus, our aim was to retarget AAV2 variants derived from a large peptide display library.Methods: The AAV2 library is based on a random 7mer peptide insertion into the viral capsid proteins.This library was selected in mice with pressure-overload induced cardiac hypertrophy with severe cardiac fibrosis.After three rounds of selection, cardiac fibroblast-enriched variants were identified via next generation sequencing.For further in depth analysis, fourteen variants were combined to a GFP-expressing barcoded sub-library that was once screened in vivo.Here, three variants were chosen for a subsequent in vitro characterization including transduction of several on and off target cells, natural AAV2 receptor affinity assays and in vitro neutralization with serum from immunized mice.Finally, the three AAV variants were examined in a proof-of-principle study in mice. Results:The results of the GFP-barcode-library screening indicated an enrichment of AAV-Var1, Var4 and Var14 vector genomes as well as the highest relative eGFP expression in cardiac fibroblasts compared to cardiomyocytes, endothelial cells and the major off target organ, the liver.In vitro studies confirmed an increased transduction efficiency of murine and human cardiac fibroblasts while off target cells were less transduced.The retargeting is accompanied by a reduced binding affinity to an AAV2 primary receptor analogue.One major challenge for clinical translation is the high prevalence of neutralizing antibodies.Therefore, the diminished recognition by AAV2 antibodies is beneficial for future studies.Finally, the enhanced tropism for cardiac fibroblasts was validated in a proof-of-principle approach in vivo.Conclusions: The three AAV variants are highly interesting novel gene therapy vectors for the treatment of cardiac fibrosis and potentially additional fibrotic diseases.Future studies will, therefore, include an in-depth analysis of their tropism, immune responses and therapeutic potential in a murine animal model.","journal":"European Journal of Heart Failure","year":2023,"id":406304,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9612,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-19T01:21:03.432924Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}