16 research outputs found
De novo design of potent and resilient hACE2 decoys to neutralize SARS-CoV-2
We developed a de novo protein design strategy to swiftly engineer decoys for neutralizing pathogens that exploit extracellular host proteins to infect the cell. Our pipeline allowed the design, validation, and optimization of de novo hACE2 decoys to neutralize SARS-CoV-2. The best decoy, CTC-445.2, binds with low nanomolar affinity and high specificity to the RBD of the spike protein. Cryo-EM shows that the design is accurate and can simultaneously bind to all three RBDs of a single spike protein. Because the decoy replicates the spike protein target interface in hACE2, it is intrinsically resilient to viral mutational escape. A bivalent decoy, CTC-445.2d, shows ~10-fold improvement in binding. CTC-445.2d potently neutralizes SARS-CoV-2 infection of cells in vitro and a single intranasal prophylactic dose of decoy protected Syrian hamsters from a subsequent lethal SARS-CoV-2 challenge
De novo design of potent and resilient hACE2 decoys to neutralize SARS-CoV-2
We developed a de novo protein design strategy to swiftly engineer decoys for neutralizing pathogens that exploit extracellular host proteins to infect the cell. Our pipeline allowed the design, validation, and optimization of de novo hACE2 decoys to neutralize SARS-CoV-2. The best decoy, CTC-445.2, binds with low nanomolar affinity and high specificity to the RBD of the spike protein. Cryo-EM shows that the design is accurate and can simultaneously bind to all three RBDs of a single spike protein. Because the decoy replicates the spike protein target interface in hACE2, it is intrinsically resilient to viral mutational escape. A bivalent decoy, CTC-445.2d, shows ~10-fold improvement in binding. CTC-445.2d potently neutralizes SARS-CoV-2 infection of cells in vitro and a single intranasal prophylactic dose of decoy protected Syrian hamsters from a subsequent lethal SARS-CoV-2 challenge
Secreted Biomolecules Alter the Biological Identity and Cellular Interactions of Nanoparticles
This document is the Accepted Manuscript version of a Published
Work that appeared in final form in ACS Nano, copyright ©American
Chemical Society after peer review and technical editing by the
publisher. To access the final edited and published work see
http://dx.doi.org/10.1021/nn4061012A nanoparticle’s physical and chemical properties at the time of cell contact will determine the ensuing cellular response. Aggregation and the formation of a protein corona in the extracellular environment will alter nanoparticle size, shape, and surface properties, giving it a “biological identity” that is distinct from its initial “synthetic identity”. The biological identity of a nanoparticle depends on the composition of the surrounding biological environment and determines subsequent cellular interactions. When studying nanoparticle–cell interactions, previous studies have ignored the dynamic composition of the extracellular environment as cells deplete and secrete biomolecules in a process known as “conditioning”. Here, we show that cell conditioning induces gold nanoparticle aggregation and changes the protein corona composition in a manner that depends on nanoparticle diameter, surface chemistry, and cell phenotype. The evolution of the biological identity in conditioned media enhances the cell membrane affinity, uptake, and retention of nanoparticles. These results show that dynamic extracellular environments can alter nanoparticle–cell interactions by modulating the biological identity. The effect of the dynamic nature of biological environments on the biological identity of nanoparticles must be considered to fully understand nano–bio interactions and prevent data misinterpretation
Protein Corona Fingerprinting Predicts the Cellular Interaction of Gold and Silver Nanoparticles
Using quantitative models to predict the biological interactions of nanoparticles will accelerate the translation of nanotechnology. Here, we characterized the serum protein corona ‘fingerprint’ formed around a library of 105 surface-modified gold nanoparticles. Applying a bioinformatics-inspired approach, we developed a multivariate model that uses the protein corona fingerprint to predict cell association 50% more accurately than a model that uses parameters describing nanoparticle size, aggregation state, and surface charge. Our model implicates a set of hyaluronan-binding proteins as mediators of nanoparticle–cell interactions. This study establishes a framework for developing a comprehensive database of protein corona fingerprints and biological responses for multiple nanoparticle types. Such a database can be used to develop quantitative relationships that predict the biological responses to nanoparticles and will aid in uncovering the fundamental mechanisms of nano–bio interactions
Nanoparticle Size and Surface Chemistry Determine Serum Protein Adsorption and Macrophage Uptake
Delivery and toxicity are critical issues facing nanomedicine
research.
Currently, there is limited understanding and connection between the
physicochemical properties of a nanomaterial and its interactions
with a physiological system. As a result, it remains unclear how to
optimally synthesize and chemically modify nanomaterials for <i>in vivo</i> applications. It has been suggested that the physicochemical
properties of a nanomaterial after synthesis, known as its “synthetic
identity”, are not what a cell encounters <i>in vivo</i>. Adsorption of blood components and interactions with phagocytes
can modify the size, aggregation state, and interfacial composition
of a nanomaterial, giving it a distinct “biological identity”.
Here, we investigate the role of size and surface chemistry in mediating
serum protein adsorption to gold nanoparticles and their subsequent
uptake by macrophages. Using label-free liquid chromatography tandem
mass spectrometry, we find that over 70 different serum proteins are
heterogeneously adsorbed to the surface of gold nanoparticles. The
relative density of each of these adsorbed proteins depends on nanoparticle
size and poly(ethylene glycol) grafting density. Variations in serum
protein adsorption correlate with differences in the mechanism and
efficiency of nanoparticle uptake by a macrophage cell line. Macrophages
contribute to the poor efficiency of nanomaterial delivery into diseased
tissues, redistribution of nanomaterials within the body, and potential
toxicity. This study establishes principles for the rational design
of clinically useful nanomaterials
Secreted Biomolecules Alter the Biological Identity and Cellular Interactions of Nanoparticles
A nanoparticle’s physical and chemical properties at the time of cell contact will determine the ensuing cellular response. Aggregation and the formation of a protein corona in the extracellular environment will alter nanoparticle size, shape, and surface properties, giving it a “biological identity” that is distinct from its initial “synthetic identity”. The biological identity of a nanoparticle depends on the composition of the surrounding biological environment and determines subsequent cellular interactions. When studying nanoparticle–cell interactions, previous studies have ignored the dynamic composition of the extracellular environment as cells deplete and secrete biomolecules in a process known as “conditioning”. Here, we show that cell conditioning induces gold nanoparticle aggregation and changes the protein corona composition in a manner that depends on nanoparticle diameter, surface chemistry, and cell phenotype. The evolution of the biological identity in conditioned media enhances the cell membrane affinity, uptake, and retention of nanoparticles. These results show that dynamic extracellular environments can alter nanoparticle–cell interactions by modulating the biological identity. The effect of the dynamic nature of biological environments on the biological identity of nanoparticles must be considered to fully understand nano–bio interactions and prevent data misinterpretation