This work developed genetically-encoded lysosome targeting chimeras (GELYTACs) that target circulating IgGs for clearance and degradation and establishes GELYTACs as a possible therapeutic modality that is deliverable using genetic medicine approaches.
Abstract
Immunoglobulins (e.g., IgGs) are critical effectors of the adaptive immune system that when overexpressed or dysregulated can result in autoimmune diseases. Thus, depletion of IgGs can be a promising therapeutic avenue. Here we developed genetically-encoded lysosome targeting chimeras (GELYTACs) that target circulating IgGs for clearance and degradation. The GELYTACs comprised two protein modules derived from insulin-like growth factor 2 (IGF2) and an IgG-binding nanobody, respectively, and mediated clearance of plasma IgG via the lysosomal trafficking receptor IGF2R. To achieve long-lasting IgG depletion, we encoded GELYTACs in an AAV gene therapy vector and established continuous expression in mice. We also developed conditional GELYACs that are activatable with disease-specific proteases or small molecule drugs. This work establishes GELYTACs as a possible therapeutic modality that is deliverable using genetic medicine approaches.
Intrinsic innate immune barriers have evolved to suppress viral infection and can reduce effective gene delivery in gene therapy. We have developed BG147, a novel cyclosporine A (CsA) analogue optimised via structure-guided design to specifically inhibit interferon-induced transmembrane proteins (IFITM1-3) but not inhibit CsA target, and HIV cofactor, cyclophilin A. BG147 enhances VSV-G pseudotyped lentiviral vector transduction ex vivo in hematopoietic stem and progenitor cells (HSPCs) and in in vivo ocular gene therapy of photoreceptor cells in mice. Upon BG147 treatment, IFITM3 protein is mislocalised and degraded through lysosomal acidification-dependent pathways but returns 96 h after BG147 washout. Critically, HSPC transduced in the presence of BG147 showed successful engraftment in NGS mice. BG147 promises to transform ex vivo and in vivo gene therapies by transiently inhibiting intrinsic immune barriers mediated by IFITM3 to enhance a wide range of protocols.
Dara Annett, Bethan J. Critchley, Kate L. Morling et al.· Molecular Therapy· 0 citations
Adeno-associated virus (AAV) gene therapy is frequently hindered by dose-limiting toxicities and preexisting neutralizing antibodies (nAbs). Here, we evaluate enhancer polymer (ePL), a cargo-less poly(L-lactic-co-glycolic acid) nanoparticle, the systemic administration of which demonstrated biocompatibility in nonhuman primates (NHPs) and generated a protransduction serum secretome that significantly enhanced AAV uptake in human iPSC-derived cardiomyocytes. Proteomic analysis of human peripheral blood mononuclear cell-derived secretomes identified a transient upregulation of AAV-entry factors, including ITGB3, alongside a downregulation of inflammatory cytokine pathways. Mechanistically, ePL-stimulated macrophages release a paracrine secretome that triggers the rapid, transient degradation of hepatic insulin receptor substrate 2 and subsequent AKT inhibition in liver and isolated primary mouse hepatocytes. Additionally, ePL attenuated the levels of NHP-derived nAbs in vitro and in a mouse-NHP xenotransfusion model without depleting total systemic immunoglobulins. Finally, ePL reduced Immunoglobulin G (IgG) secretory capacity of splenic B cells, suggesting a mechanistic link by which levels of nAbs are likely attenuated. Together, these findings highlight ePL as a promising supporting agent to improve AAV gene transfer, warranting its further optimization for clinical translation.
Lauren Switala, A. Khandaker, Sumita Dutta et al.· Human Gene Therapy· 0 citations
The integration of rational material design, high-throughput screening, artificial intelligence, and interdisciplinary collaboration will be essential to advance next-generation targeted in vivo mRNA cell therapies toward clinical translation.
Danyang Wang, Yumin Li, Jinfeng Deng et al.· Drug Delivery· 0 citations
ABSTRACT Targeted chimeras have reshaped therapeutic design by converting target recognition into active degradation. As one of the most clinically established therapeutic modalities, antibodies provide high affinity and specificity to the protein of interest. Antibody‐associated targeted chimeras (AbTACs) are emerging as an important class of biologic degraders for targeted protein elimination, particularly of extracellular and membrane‐associated proteins. AbTACs offer a strategy to extend its recognition capacity beyond target binding by coupling defined degradation pathway. In these systems, antibody‐derived binders serve as programmable recognition modules, while conjugated ligands, encoded domains, recruited receptors, or nanoparticle scaffolds determine the target's intracellular fate. This review discusses the conceptual evolution of AbTACs and classifies current platforms according to scaffold architecture and engineering strategies, which link target binding to intracellular routing and subsequent clearance. Furthermore, it highlights the design principles and translational barriers that will guide the development of next‐generation antibody‐associated degraders.
Kaige Chen, Quanyin Hu· Advancement of science· 0 citations
Achieving efficient DNA delivery for sustained transgene expression while minimizing immune response remains a significant challenge in gene therapy. Here, we conduct an in-depth characterization of red blood cell-derived extracellular vesicles (RBCEVs) and evaluate their potential as DNA delivery vehicles targeting specific cell types. We aim to achieve stable, prolonged transgene expression, minimizing the need for frequent treatments. Proteomic analysis shows that RBCEVs closely resemble red blood cells in protein content with over 90% of lumen proteins comprised of hemoglobin family proteins. Biodistribution of RBCEVs in non-human primates indicates predominant liver accumulation, highlighting the liver's potential as a biofactory organ for RBCEV-mediated gene therapies. In mice, systemic administration of RBCEVs loaded with luciferase plasmids achieves stable, long-lasting luciferase expression, maintained throughout a 13-month monitoring period. RBCEV-mediated delivery of therapeutic human factor IX plasmids produces durable factor IX protein levels in bloodstream. RBCEVs can also co-deliver two plasmids simultaneously. Incorporating heavy and light chain antibody constructs into RBCEVs enables sustained expression of Herceptin antibodies in circulation. Further utilization of cell-specific promoters enhances transgene expression and concomitantly reduces undesired immune responses. These results highlight RBCEVs as a safe, scalable, and versatile DNA delivery platform for achieving sustained transgene expression in gene therapy.
Melissa Tan, Yumi Kawamura, Carol Wang et al.· Molecular Therapy· 0 citations
An acid-responsive nanoplatform using amorphous carbonated calcium phosphate nanoparticles (ACCP NPs) for effective intracellular co-delivery of TRIM21 and antibodies is disclosed, establishing ACCP NP-based TPD as a versatile and efficient platform for TRIM21/antibody-mediated degradation and a promising strategy for targeting other "undruggable" proteins.
L. Peng, Jiaoyu Chen, Xia Liu et al.· Angewandte Chemie· 0 citations
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