β2GPI-targeted polymeric nanoparticles form a protective layer to prevent vascular thrombosis in an anti-phospholipid syndrome model Paolo Durigutto, Maria Cristina Grimaldi, Sara Bozzer, Elena Raschi, Pierluigi Meroni, Francesco Tedesco, Paolo Macor Frontiers in Immunology, 2025 Anti-phospholipid syndrome (APS) is a systemic autoimmune disease characterized by thrombotic vascular occlusion and maternal morbidity. Anti-coagulants remain pivotal drugs for the management of APS, but a significant proportion of patients do not benefit from long-term anti-coagulation and may require an alternative therapy to prevent antibody deposition and vascular thrombosis. We have developed a therapeutic approach based on the use of safe polymeric nanoparticles that selectively target beta2-glycoprotein I (β2GPI) deposited on endothelial cells (tNPs). Their efficacy was tested in a rat model of APS developed by infusing patients’ sera containing medium–high titer antibodies against domain I of β2GPI. The tNPs bearing a CH2-deleted anti-β2GPI recombinant antibody as a targeting agent recognize β2GPI deposited on endothelial cells but failed to induce blood clot formation. The tNPs infused into rats immediately before APS sera competed with patients’ antibodies, preventing their binding to deposited β2GPI and, as a consequence, resulted in thrombus formations and occlusion of mesenteric vessels. Similar results were obtained by injecting tNPs 24 hours before the administration of patients’ sera to induce blood clot formation. Our findings suggest that β2GPI-targeted polymeric nanoparticles represent a stable and safe approach to prevent thrombus formation and vessel occlusion in a rat model of APS and may be used to control thrombosis developing in APS patients as a result of acute triggering events.
Stealth-Engineered Albumin-Coated Nanoparticles for Targeted Therapy: Effective Drug Delivery and Tumor Suppression in Xenograft-Zebrafish Model Sara Bozzer, Maria Cristina Grimaldi, Luca De Maso, Marcello Manfredi, Giuseppe Toffoli, Michele Dal Bo, Daniele Sblattero, Paolo Macor International Journal of Nanomedicine, 2024 Purpose: In the bloodstream, nanoparticles (NPs) interact with serum proteins to form the protein corona, which includes both opsonins, promoting NP recognition and elimination, and dysopsonins, which can inhibit opsonin activity. Albumin, the most abundant serum protein, is part of this corona and can act as a dysopsonin, potentially hiding NPs from the immune system. This study aims to investigate how a covalently bound layer of human serum albumin (HSA) on polymeric NPs affects the protein corona and their behavior in the immune system. Methods: We covalently attached HSA to the surface of polymeric NPs to modify the protein corona composition. These HSA-covered nanostructures were then decorated with an anti-CD19 recombinant antibody fragment to target malignant B cells, specifically acute lymphoblastic leukemia (ALL) cells. The safety profile and bioavailability of these targeted HSA-nanoparticles were evaluated in vitro and in vivo using a human-zebrafish xenograft model of ALL. The efficacy of the nanostructures in delivering encapsulated doxorubicin and suppressing tumor growth was also assessed. Results: The HSA coating on polymeric NPs effectively modified the protein corona, preventing opsonization and subsequent macrophage-mediated elimination. The targeted HSA-nanoparticles maintained a safe profile with reduced macrophage interaction and specifically targeted tumor cells in the xenograft model. This resulted in the successful delivery of doxorubicin, tumor growth suppression, and increased survival of the model organisms. Conclusion: The study demonstrates that HSA-coated nanoparticles can be used as a therapeutic nanoplatform with a safe profile and enhanced bioavailability. The ability to decorate these nanostructures with specific targeting agents, such as anti-CD19 antibodies, opens up the potential for developing versatile therapeutic platforms that can be tailored to target various clinical conditions.
DNA-loaded targeted nanoparticles as a safe platform to produce exogenous proteins in tumor B cells Maria Cristina Grimaldi, Sara Bozzer, Dick J. Sjöström, Linnea I. Andersson, Tom Eirik Mollnes, Per H. Nilsson, Luca De Maso, Federico Riccardi, Michele Dal Bo, Daniele Sblattero, Paolo Macor Frontiers in Immunology, 2024 IntroductionThe functionalization of nanoparticles (NPs) with an antiCD19 targeting mechanism represents a promising approach for the selective delivery of drugs and nucleic acids into normal and tumor B cells. This strategy has the advantage of minimizing off-target effects by restricting gene delivery to the desired cell population. However, the nanoplatform must guarantee both the local production of the protein and the safety of the treatment to allow an effective therapy with reduced systemic toxicity.MethodsIn order to ensure a selective delivery of nucleic acids, we developed poly(lactic-co-glycolic acid) (PLGA)-poly(vinyl alcohol) (PVA) NPs loaded with an Enhanced Green Fluorescent Protein (EGFP)-coding plasmid and covalently coated with antiCD19 recombinant antibody as a targeting mechanism. To assess the functionality of the NPs, physicochemical characterization, safety tests, and transfection assay were employed to evaluate the NPs’ behavior in vitro and in vivo, in a human/zebrafish lymphoma xenograft model.ResultsThe results demonstrated that the PLGA-PVA nanoplatform was capable of efficiently encapsulating and releasing the payload. These nanostructures demonstrated a favorable safety profile, as evidenced by the absence of significant cell cytotoxicity, coagulation activation, complement system activation, and the slight activation of endothelial cells and leukocytes. The targeting mechanism facilitated the interaction of NPs with target cells, thereby enhancing their internalization and subsequent exogenous plasmid DNA (pDNA) translation and protein expression. In the human/zebrafish lymphoma xenograft model, no evidence of toxicity was observed, and targeted NPs demonstrated the capacity to enhance exogenous pDNA expression.ConclusionOur findings provide a rationale for the use of targeted NPs as a DNA delivery system for the local expression of therapeutic proteins.
Nanocarriers as a Delivery Platform for Anticancer Treatment: Biological Limits and Perspectives in B-Cell Malignancies Sara Bozzer, Michele Dal Bo, Maria Cristina Grimaldi, Giuseppe Toffoli, Paolo Macor Pharmaceutics, 2022 Nanoparticle-based therapies have been proposed in oncology research using various delivery methods to increase selectivity toward tumor tissues. Enhanced drug delivery through nanoparticle-based therapies could improve anti-tumor efficacy and also prevent drug resistance. However, there are still problems to overcome, such as the main biological interactions of nanocarriers. Among the various nanostructures for drug delivery, drug delivery based on polymeric nanoparticles has numerous advantages for controlling the release of biological factors, such as the ability to add a selective targeting mechanism, controlled release, protection of administered drugs, and prolonging the circulation time in the body. In addition, the functionalization of nanoparticles helps to achieve the best possible outcome. One of the most promising applications for nanoparticle-based drug delivery is in the field of onco-hematology, where there are many already approved targeted therapies, such as immunotherapies with monoclonal antibodies targeting specific tumor-associated antigens; however, several patients have experienced relapsed or refractory disease. This review describes the major nanocarriers proposed as new treatments for hematologic cancer, describing the main biological interactions of these nanocarriers and the related limitations of their use as drug delivery strategies.
Zebrafish: A Useful Animal Model for the Characterization of Drug-Loaded Polymeric NPs Sara Bozzer, Luca De Maso, Maria Cristina Grimaldi, Sara Capolla, Michele Dal Bo, Giuseppe Toffoli, Paolo Macor Biomedicines, 2022 The use of zebrafish (ZF) embryos as an in vivo model is increasingly attractive thanks to different features that include easy handling, transparency, and the absence of adaptive immunity until 4–6 weeks. These factors allow the development of xenografts that can be easily analyzed through fluorescence techniques. In this work, ZF were exploited to characterize the efficiency of drug-loaded polymeric NPs as a therapeutical approach for B-cell malignancies. Fluorescent probes, fluorescent transgenic lines of ZF, or their combination allowed to deeply examine biodistribution, elimination, and therapeutic efficacy. In particular, the fluorescent signal of nanoparticles (NPs) was exploited to investigate the in vivo distribution, while the colocalization between the fluorescence in macrophages and NPs allows following the elimination pathway of these polymeric NPs. Xenotransplanted human B-cells (Nalm-6) developed a reproducible model useful for demonstrating drug delivery by polymeric NPs loaded with doxorubicin and, as a consequence, the arrest of tumor growth and the reduction in tumor burden. ZF proved to be a versatile model, able to rapidly provide answers in the development of animal models and in the characterization of the activity and the efficacy of drug delivery systems.
