Endosomal escape of protein nanoparticles engineered through humanized histidine-rich peptides

Altres ajuts: EU COST Action CA 17140. AV received an ICREA ACADEMIA awardPoly-histidine peptides such as H6 (HHHHHH) are used in protein biotechnologies as purification tags, protein-assembling agents and endosomal-escape entities. The pleiotropic properties of such peptides make them appealing to design protein-based smart materials or nanoparticles for imaging or drug delivery to be produced in form of recombinant proteins. However, the clinical applicability of H6-tagged proteins is restricted by the potential immunogenicity of these segments. In this study, we have explored several humanized histidine-rich peptides in tumor-targeted modular proteins, which can specifically bind and be internalized by the target cells through the tumoral marker CXCR4. We were particularly interested in exploring how protein purification, self-assembling and endosomal escape perform in proteins containing the variant histidine-rich tags. Among the tested candidates, the peptide H5E (HEHEHEHEH) is promising as a good promoter of endosomal escape of the associated full-length protein upon endosomal internalization. The numerical modelling of cell penetration and endosomal escape of the tested proteins has revealed a negative relationship between the amount of protein internalized into target cells and the efficiency of cytoplasmic release. This fact demonstrates that the His-mediated, proton sponge-based endosomal escape saturates at moderate amounts of internalized protein, a fact that might be critical for the design of protein materials for cytosolic molecular delivery

Biofabricació de nanopartícules proteiques funcionals mitjançant l'ús de cues d'histidina

Investigadors del grup de Nanobiotecnologia del IBB-UAB en col·laboració amb CIBER-BBN i ICTS-Nanbiosis-PPP han desenvolupat una nova tècnica de fabricació de nanopartícules proteiques amb funcionalitats úniques i útils a la biomedicina i la biotecnologia. El procediment de síntesi, eficient i econòmic, es podueix mitjançant l'ús de pèptids d'histidina i de cations divalents.Investigadores del grupo de Nanobiotecnología del IBB-UAB en colaboración con CIBER-BBN e ICTS-Nanbiosis-PPP han desarrollado una nueva técnica de fabricación de nanopartículas proteicas con funcionalidades únicas y útiles en la biomedicina y la biotecnología. El procedimiento de síntesis, eficiente y económico, se produce mediante el uso de péptidos de histidina y de cationes divalentes.Researchers from the IBB-UAB Nanobiotechnology group in collaboration with CIBER-BBN and ICTS-Nanbiosis-PPP have developed a new technique for the fabrication of protein nanoparticles with unique and useful functionalities in biomedicine and biotechnology. The efficient and economical synthesis procedure is performed using histidine peptides and divalent cations

Insights on the emerging biotechnology of histidine-rich peptides

Altres ajuts: Acord transformatiu CRUE-CSICIn the late 70's, the discovery of the restriction enzymes made possible the biological production of functional proteins by recombinant DNA technologies, a fact that largely empowered both biotechnological and pharmaceutical industries. Short peptides or small protein domains, with specific molecular affinities, were developed as purification tags in downstream processes to separate the target protein from the culture media or cell debris, upon breaking the producing cells. Among these tags, and by exploiting the interactivity of the imidazole ring of histidine residues, the hexahistidine peptide (H6) became a gold standard. Although initially used almost exclusively in protein production, H6 and related His-rich peptides are progressively proving a broad applicability in novel utilities including enzymatic processes, advanced drug delivery systems and diagnosis, through a so far unsuspected adaptation of their binding capabilities. In this context, the coordination of histidine residues and metals confers intriguing functionalities to His-rich sequences useable in the forward-thinking design of protein-based nano- and micro-materials and devices, through strategies that are comprehensively presented here

Protein features instruct the secretion dynamics from metal-supported synthetic amyloids

Hexahistidine-tagged proteins can be clustered by divalent cations into self-containing, dynamic protein depots at the microscale, which under physiological conditions leak functional protein. While such protein granules show promise in clinics as time-sustained drug delivery systems, little is known about how the nature of their components, that is, the protein and the particular cation used as cross-linker, impact on the disintegration of the material and on its secretory performance. By using four model proteins and four different cation formulations to control aggregation, we have here determined a moderate influence of the used cation and a potent impact of some protein properties on the release kinetics and on the final fraction of releasable protein. In particular, the electrostatic charge at the amino terminus and the instability and hydropathicity indexes determine the disintegration profile of the depot. These data offer clues for the fabrication of efficient and fully exploitable secretory granulesthat being biocompatible and chemically homogenous allow their tailored use as drug delivery platforms in biological systems

High-precision targeting and destruction of cancer-associated PDGFR-β+ stromal fibroblasts through self-assembling, protein-only nanoparticles

Altres ajuts: acords transformatius de la UABThe need for more effective and precision medicines for cancer has pushed the exploration of new materials appropriate for drug delivery and imaging, and alternative receptors for targeting. Among the most promising strategies, finding suitable cell surface receptors and targeting agents for cancer-associated platelet derived growth factor receptor β (PDGFR-β)+ stromal fibroblasts is highly appealing. As a neglected target, this cell type mechanically and biologically supports the growth, progression, and infiltration of solid tumors in non-small cell lung, breast, pancreatic, and colorectal cancers. We have developed a family of PDGFR-β-targeted nanoparticles based on biofabricated, self-assembling proteins, upon hierarchical and iterative selective processes starting from four initial candidates. The modular protein PDGFD-GFP-H6 is well produced in recombinant bacteria, resulting in structurally robust oligomeric particles that selectively penetrates into PDGFR-β+ stromal fibroblasts in a dose-dependent manner, by means of the PDGFR-β ligand PDGFD. Upon in vivo administration, these GFP-carrying protein nanoparticles precisely accumulate in tumor tissues and enlighten them for IVIS observation. When GFP is replaced by a microbial toxin, selective tumor tissue destruction is observed associated with a significant reduction in tumor volume growth. The presented data validate the PDGFR-β/PDGFD pair as a promising toolbox for targeted drug delivery in the tumor microenvironment and oligomeric protein nanoparticles as a powerful instrument to mediate highly selective biosafe targeting in cancer through non-cancer cells. Statement of significance: We have developed a transversal platform for nanoparticle-based drug delivery into cancer-associated fibroblasts. This is based on the engineered modular protein PDGFD-GFP-H6 that spontaneously self-assemble and selectively penetrates into PDGFR-β+ stromal fibroblasts in a dose-dependent manner, by means of the PDGFR-β ligand PDGFD. In vivo, these protein nanoparticles accumulate in tumor and when incorporating a microbial toxin, they destroy tumor tissues with a significant reduction in tumor volume, in absence of side toxicities. The data presented here validate the PDGFR-β/PDGFD pair as a fully versatile toolbox for targeted drug delivery in the tumor microenvironment intended as a synergistic treatment

The spectrum of building block conformers sustains the biophysical properties of clinically-oriented self-assembling protein nanoparticles

Altres ajuts: Acord transformatiu CRUE-CSICHistidine-rich peptides confer self-assembling properties to recombinant proteins through the supramolecular coordination with divalent cations. This fact allows the cost-effective, large-scale generation of microscopic and macroscopic protein materials with intriguing biomedical properties. Among such materials, resulting from the simple bioproduction of protein building blocks, homomeric nanoparticles are of special value as multivalent interactors and drug carriers. Interestingly, we have here identified that the assembly of a given His-tagged protein might render distinguishable categories of self-assembling protein nanoparticles. This fact has been scrutinized through the nanobody-containing fusion proteins EM1-GFP-H6 and A3C8-GFP-H6, whose biosynthesis results in two distinguishable populations of building blocks. In one of them, the assembling and disassembling is controllable by cations. However, a second population immediately self-assembles upon purification through a non-regulatable pathway, rendering larger nanoparticles with specific biological properties. The structural analyses of both model proteins and nanoparticles revealed important conformational variability in the building blocks. This fact renders different structural and functional categories of the final soft materials resulting from the participation of energetically unstable intermediates in the oligomerization process. These data illustrate the complexity of the His-mediated protein assembling in recombinant proteins but they also offer clues for a better design and refinement of protein-based nanomedicines, which, resulting from biological fabrication, show an architectonic flexibility unusual among biomaterials

Controlling self-assembling and tumor cell-targeting of protein-only nanoparticles through modular protein engineering

Altres ajuts: EU COST Action CA 17140. Villaverde A received an ICREA ACADEMIA award. Unzueta was supported by PERIS program from the Health Department of la Generalitat de Catalunya.Modular protein engineering is suited to recruit complex and multiple functionalities in single-chain polypeptides. Although still unexplored in a systematic way, it is anticipated that the positioning of functional domains would impact and refine these activities, including the ability to organize as supramolecular entities and to generate multifunctional protein materials. To explore this concept, we have repositioned functional segments in the modular protein T22-GFP-H6 and characterized the resulting alternative fusions. In T22-GFP-H6, the combination of T22 and H6 promotes self-assembling as regular nanoparticles and selective binding and internalization of this material in CXCR4-overexpressing tumor cells, making them appealing as vehicles for selective drug delivery. The results show that the pleiotropic activities are dramatically affected in module-swapped constructs, proving the need of a carboxy terminal positioning of H6 for protein self-assembling, and the accommodation of T22 at the amino terminus as a requisite for CXCR4 cell binding and internalization. Furthermore, the failure of self-assembling as regular oligomers reduces cellular penetrability of the fusions while keeping the specificity of the T22-CXCR4 interaction. All these data instruct how multifunctional nanoscale protein carriers can be designed for smart, protein-driven drug delivery, not only for the treatment of CXCR4 human neoplasias, but also for the development of anti-HIV drugs and other pathologies in which CXCR4 is a relevant homing marker

Artificial inclusion bodies for clinical development

Bacterial inclusion bodies (IBs) are mechanically stable protein particles in the microscale, which behave as robust, slow-protein-releasing amyloids. Upon exposure to cultured cells or upon subcutaneous or intratumor injection, these protein materials secrete functional IB polypeptides, functionally mimicking the endocrine release of peptide hormones from secretory amyloid granules. Being appealing as delivery systems for prolonged protein drug release, the development of IBs toward clinical applications is, however, severely constrained by their bacterial origin and by the undefined and protein-to-protein, batch-to-batch variable composition. In this context, the de novo fabrication of artificial IBs (ArtIBs) by simple, cell-free physicochemical methods, using pure components at defined amounts is proposed here. By this, the resulting functional protein microparticles are intriguing, chemically defined biomimetic materials that replicate relevant functionalities of natural IBs, including mammalian cell penetration and local or remote release of functional ArtIB-forming protein. In default of severe regulatory issues, the concept of ArtIBs is proposed as a novel exploitable category of biomaterials for biotechnological and biomedical applications, resulting from simple fabrication and envisaging soft developmental routes to clinic

Assembly of histidine-rich protein materials controlled through divalent cations

Nanostructured protein materials show exciting biomedical applications, since both structure and function can be genetically programmed. In particular, self-assembling histidine-rich proteins benefit from functional plasticity that allows the generation of protein-only nanoparticles for cell targeted drug delivery. However, the rational development of constructs with improved functions is limited by a poor control of the oligomerization process. By exploring cross-interactions between histidine-tagged building blocks, we have identified a critical architectonic role of divalent cations. The obtained data instruct about how histidine-rich protein materials can be assembled, disassembled and reassembled within the nanoscale through the stoichiometric manipulation of divalent ions, in a biochemical approach to biomaterials design. Statement of Significance: Divalent metal and non-metal cations such as Ni, Cu Ca and Zn have been identified as unexpected molecular tools to control the assembling, disassembling and reassembling of histidine-rich protein materials at the nanoscale. Their stoichiometric manipulation allows generating defined protein-protein cross-molecular contacts between building blocks, for a powerful nano-biochemical manipulation of the material's architecture

Nanostructure empowers active tumor targeting in ligand-based molecular delivery

Altres ajuts: to EU COST Action CA 17140 and ICREA AcademiaCell-selective targeting is expected to enhance effectiveness and minimize side effects of cytotoxic agents. Functionalization of drugs or drug nanoconjugates with specific cell ligands allows receptor-mediated selective cell delivery. However, it is unclear whether the incorporation of an efficient ligand into a drug vehicle is sufficient to ensure proper biodistribution upon systemic administration, and also at which extent biophysical properties of the vehicle may contribute to the accumulation in target tissues during active targeting. To approach this issue, structural robustness of self-assembling, protein-only nanoparticles targeted to the tumoral marker CXCR4 is compromised by reducing the number of histidine residues (from six to five) in a histidine-based architectonic tag. Thus, the structure of the resulting nanoparticles, but not of building blocks, is weakened. Upon intravenous injection in animal models of human CXCR4 colorectal cancer, the administered material loses the ability to accumulate in tumor tissue, where it is only transiently found. It instead deposits in kidney and liver. Therefore, precise cell-targeted delivery requires not only the incorporation of a proper ligand that promotes receptor-mediated internalization, but also, unexpectedly, its maintenance of a stable multimeric nanostructure that ensures high ligand exposure and long residence time in tumor tissue