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Leyva-Grado VH, Marin A, Hlushko R, Yunus AS, Promeneur D, Luckay A, Lazaro GG, Hamm S, Dimitrov AS, Broder CC, Andrianov AK. Nano-Assembled Polyphosphazene Delivery System Enables Effective Intranasal Immunization with Nipah Virus Subunit Vaccine. ACS APPLIED BIO MATERIALS 2024; 7:4133-4141. [PMID: 38812435 DOI: 10.1021/acsabm.4c00441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
The ultimate vaccine against infections caused by Nipah virus should be capable of providing protection at the respiratory tract─the most probable port of entry for this pathogen. Intranasally delivered vaccines, which target nasal-associated lymphoid tissue and induce both systemic and mucosal immunity, are attractive candidates for enabling effective vaccination against this lethal disease. Herein, the water-soluble polyphosphazene delivery vehicle assembles into nanoscale supramolecular constructs with the soluble extracellular portion of the Hendra virus attachment glycoprotein─a promising subunit vaccine antigen against both Nipah and Hendra viruses. These supramolecular constructs signal through Toll-like receptor 7/8 and promote binding interactions with mucin─an important feature of effective mucosal adjuvants. High mass contrast of phosphorus-nitrogen backbone of the polymer enables a successful visualization of nanoconstructs in their vitrified state by cryogenic electron microscopy. Here, we characterize the self-assembly of polyphosphazene macromolecule with biologically relevant ligands by asymmetric flow field flow fractionation, dynamic light scattering, fluorescence spectrophotometry, and turbidimetric titration methods. Furthermore, a polyphosphazene-enabled intranasal Nipah vaccine candidate demonstrates the ability to induce immune responses in hamsters and shows superiority in inducing total IgG and neutralizing antibodies when benchmarked against the respective clinical stage alum adjuvanted vaccine. The results highlight the potential of polyphosphazene-enabled nanoassemblies in the development of intranasal vaccines.
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Affiliation(s)
- Victor H Leyva-Grado
- Auro Vaccines LLC, 401 Middletown Rd. Bldg. 205, Pearl River, New York 10965, United States
| | - Alexander Marin
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Raman Hlushko
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Abdul S Yunus
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Dominique Promeneur
- Auro Vaccines LLC, 401 Middletown Rd. Bldg. 205, Pearl River, New York 10965, United States
| | - Amara Luckay
- Auro Vaccines LLC, 401 Middletown Rd. Bldg. 205, Pearl River, New York 10965, United States
| | - Glorie G Lazaro
- Auro Vaccines LLC, 401 Middletown Rd. Bldg. 205, Pearl River, New York 10965, United States
| | - Stefan Hamm
- Auro Vaccines LLC, 401 Middletown Rd. Bldg. 205, Pearl River, New York 10965, United States
| | - Antony S Dimitrov
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland 20814, United States
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland 20814, United States
| | - Christopher C Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland 20814, United States
| | - Alexander K Andrianov
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
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Hlushko R, Pozharski E, Prabhu VM, Andrianov AK. Directly visualizing individual polyorganophosphazenes and their single-chain complexes with proteins. COMMUNICATIONS MATERIALS 2024; 5:36. [PMID: 38817739 PMCID: PMC11139433 DOI: 10.1038/s43246-024-00476-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 03/07/2024] [Indexed: 06/01/2024]
Abstract
Polyorganophosphazenes are water-soluble macromolecules with immunoadjuvant activity that self-assemble with proteins to enable biological functionality. Direct imaging by cryogenic electron microscopy uncovers the coil structure of those highly charged macromolecules. The successful visualization of individual polymer chains within the vitrified state is achieved in the absence of additives for contrast enhancement and is attributed to the high mass contrast of the inorganic backbone. Upon assembly with proteins, multiple protein copies bind at the single polymer chain level resulting in structures reminiscent of compact spherical complexes or stiffened coils. The outcome depends on protein characteristics and cannot be deduced by commonly used characterization techniques, such as light scattering, thus revealing direct morphological insights crucial for understanding biological activity. Atomic force microscopy supports the morphology outcomes while advanced analytical techniques confirm protein-polymer binding. The chain visualization methodology provides tools for gaining insights into the processes of supramolecular assembly and mechanistic aspects of polymer enabled vaccine delivery.
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Affiliation(s)
- Raman Hlushko
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States of America
| | - Edwin Pozharski
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States of America
| | - Vivek M. Prabhu
- Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology‡, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States of America
| | - Alexander K. Andrianov
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States of America
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Marin A, Kethanapalli SH, Andrianov AK. Immunopotentiating Polyphosphazene Delivery Systems: Supramolecular Self-Assembly and Stability in the Presence of Plasma Proteins. Mol Pharm 2024; 21:791-800. [PMID: 38206583 PMCID: PMC11164237 DOI: 10.1021/acs.molpharmaceut.3c00916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Studies on the biological performance of nanomedicines have been increasingly focused on the paradigm shifting role of the protein corona, which is imminently formed once the formulation is placed in a complex physiological environment. This phenomenon is predominantly studied in the context of protein adsorption science, while such interactions for water-soluble systems remain virtually unexplored. In particular, the importance of plasma protein binding is yet to be understood for pharmaceuticals designed on the basis of supramolecular architectures, which generally lack well-defined surfaces. Water-soluble ionic polyphosphazenes, clinically proven immunoadjuvants and vaccine delivery vehicles, represent an example of a system that requires supramolecular coassembly with antigenic proteins to attain an optimal immunopotentiating effect. Herein, the self-assembly behavior and stability of noncovalently bound complexes on the basis of a model antigen─hen egg lysozyme─and polyphosphazene adjuvant are studied in the presence of plasma proteins utilizing isothermal calorimetry, asymmetric flow field flow fractionation, dynamic light scattering, and size exclusion chromatography methods. The results demonstrate that although plasma proteins, such as human serum albumin (HSA), show detectable avidity to polyphosphazene, the strength of such interactions is significantly lower than that for the model antigen. Furthermore, thermodynamic parameters indicate different models of binding: entropy driven, which is consistent with the counterion release mechanism for albumin versus electrostatic interactions for lysozyme, which are characterized by beneficial enthalpy changes. In vitro protein release experiments conducted in Franz diffusion cells using enzyme-linked immunoassay detection suggest that the antigen-adjuvant complex stability is not adversely affected by the presence of the most physiologically abundant protein, which confirms the importance of the delivery modality for this immunoadjuvant. Moreover, HSA shows an unexpected stabilizing effect on complexes with high antigen load─an important consideration for further development of polyphosphazene adjuvanted vaccine formulations and their functional assessment.
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Affiliation(s)
- Alexander Marin
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Sri H. Kethanapalli
- University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
| | - Alexander K. Andrianov
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
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Andrianov A, Hlushko R, Pozharski E, Prabhu V. Cryo-EM and AFM visualize linear polyorganophosphazene: individual chains and single-chain assemblies with proteins. RESEARCH SQUARE 2023:rs.3.rs-3411603. [PMID: 37961436 PMCID: PMC10635375 DOI: 10.21203/rs.3.rs-3411603/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Polyorganophosphazenes are biodegradable macromolecules with potent immunoadjuvant activity that self-assemble with protein antigens to provide biological activity. Direct imaging by cryogenic electron microscopy reveals the coil structure of the highly-charged high molecular mass synthetic polyorganophosphazenes within the vitrified state without any additives for contrast enhancement for the first time. Upon mixing with protein antigens under a controlled stoichiometric ratio, multiple proteins bind at the single chain level revealing a structural change reminiscent of compact spherical complexes or stiffened coils depending on the bound protein antigen. The structural outcome depends on the protein charge density that cannot be deduced by methods, such as dynamic light scattering, thus revealing direct morphological insight necessary to understand in vivo biological activity. Complementary atomic force microscopy supports the binding morphology outcomes as well as additional analytical techniques that indicate binding. These observations open opportunities to understand supramolecular assembly of proteins and other biomacromolecules at the single chain level with highly charged polyelectrolytes for vaccines as well as important to developing fields such as polyelectrolyte complex coacervation.
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Tagad HD, Marin A, Wang R, Yunus AS, Fuerst TR, Andrianov AK. Fluorine-Functionalized Polyphosphazene Immunoadjuvant: Synthesis, Solution Behavior and In Vivo Potency. Molecules 2023; 28:4218. [PMID: 37241958 PMCID: PMC10221343 DOI: 10.3390/molecules28104218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 05/28/2023] Open
Abstract
The inclusion of fluorine motifs in drugs and drug delivery systems is an established tool for modulating their biological potency. Fluorination can improve drug specificity or boost the vehicle's ability to cross cellular membranes. However, the approach has yet to be applied to vaccine adjuvants. Herein, the synthesis of fluorinated bioisostere of a clinical stage immunoadjuvant-poly[di(carboxylatophenoxy)phosphazene], PCPP-is reported. The structure of water-soluble fluoropolymer-PCPP-F, which contains two fluorine atoms per repeat unit-was confirmed using 1H, 31P and 19F NMR, and its molecular mass and molecular dimensions were determined using size-exclusion chromatography and dynamic light scattering. Insertion of fluorine atoms in the polymer side group resulted in an improved solubility in acidic solutions and faster hydrolytic degradation rate, while the ability to self-assemble with an antigenic protein, lysozyme-an important feature of polyphosphazene vaccine adjuvants-was preserved. In vivo assessment of PCPP-F demonstrated its greater ability to induce antibody responses to Hepatitis C virus antigen when compared to its non-fluorinated counterpart. Taken together, the superior immunoadjuvant activity of PCPP-F, along with its improved formulation characteristics, demonstrate advantages of the fluorination approach for the development of this family of macromolecular vaccine adjuvants.
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Affiliation(s)
- Harichandra D. Tagad
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Alexander Marin
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Ruixue Wang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Abdul S. Yunus
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Thomas R. Fuerst
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Alexander K. Andrianov
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
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Hyaluronan-cecropin B interactions studied by ultrasound velocimetry and isothermal titration calorimetry. Int J Biol Macromol 2023; 227:786-794. [PMID: 36549616 DOI: 10.1016/j.ijbiomac.2022.12.144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 12/07/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Interactions between hyaluronan and the antimicrobial peptide cecropin B were studied in water and PBS using high-resolution ultrasonic spectroscopy and isothermal titration calorimetry. Although each technique is fundamentally different, they both gave identical results. It was found that the molecular weight of hyaluronan plays an important role in the interactions - in particular, the transition between the rod conformation and the random coil conformation. In water, interactions were saturated in a molar charge ratio of 1.5 and not 1.0 as expected. The later saturation of the interaction probably occurred either for steric reasons or due to the interaction between functional groups in the cecropin structure, which allowed complete dissociation of the antimicrobial peptide. In PBS, in contrast to water, no interactions were observed, irrespective of the molecular weight of hyaluronan. Thus, at a sufficiently high ionic strength, the interactions were suppressed.
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