The research we fund today will improve the health of people who will live tomorrow. But future people will not all benefit equally: decisions we make about what research to prioritize will predictably affect when and...
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The research we fund today will improve the health of people who will live tomorrow. But future people will not all benefit equally: decisions we make about what research to prioritize will predictably affect when and how much different people benefit from research. Organizations that fund health research should thus fairly account for the health needs of future populations when setting priorities. To this end, some research funders aim to allocate research resources in accordance with disease burden, prioritizing illnesses that cause more morbidity and mortality. In this article, I defend research funders' practice of aligning research funding with disease burden but argue that funders should aim to align research funding with future-rather than present-disease burden. I suggest that research funders should allocate research funding in proportion to aggregated estimates of disease burden over the period when research could plausibly start to yield benefits until indefinitely into the future.
To realize the full potential of emerging nucleic acid therapies, there is a need for effective delivery agents to transport cargo to cells of interest. Protein materials exhibit several unique properties, including b...
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To realize the full potential of emerging nucleic acid therapies, there is a need for effective delivery agents to transport cargo to cells of interest. Protein materials exhibit several unique properties, including biodegradability, biocompatibility, ease of functionalization via recombinant and chemical modifications, among other features, which establish a promising basis for therapeutic nucleic acid delivery systems. In this review, we highlight progress made in the use of non-viral protein-based nanoparticles for nucleic acid delivery in vitro and in vivo, while elaborating on key physicochemical properties that have enabled the use of these materials for nanoparticle formulation and drug delivery. To conclude, we comment on the prospects and unresolved challenges associated with the translation of protein-based nucleic acid delivery systems for therapeutic applications.
Human telomere length is tightly regulated and associated with diseases at either extreme, but how these bounds are established remains incompletely understood. Here, we developed a rapid cell-based telomere synthesis...
Human telomere length is tightly regulated and associated with diseases at either extreme, but how these bounds are established remains incompletely understood. Here, we developed a rapid cell-based telomere synthesis assay and found that nucleoside salvage bidirectionally constrains human telomere length. Metabolism of deoxyguanosine (dG) or guanosine via purine nucleoside phosphorylase (PNP) and hypoxanthine-guanine phosphoribosyltransferase to form guanine ribonucleotides strongly inhibited telomerase and shortened telomeres. Conversely, salvage of dG to its nucleotide forms via deoxycytidine kinase drove potent telomerase activation, the extent of which was controlled by the dNTPase SAMHD1. Circumventing limits on salvage by expressing Drosophila melanogaster deoxynucleoside kinase or augmenting dG metabolism using the PNP inhibitor ulodesine robustly lengthened telomeres in human cells, including those from patients with lethal telomere diseases. Our results provide an updated paradigm for telomere length control, wherein telomerase reverse transcriptase activity is actively and bidirectionally constrained by the availability of its dNTP substrates, in a manner that may be therapeutically actionable.
Inhaled delivery of mRNA has the potential to treat a wide variety of diseases. However, nebulized mRNA lipid nanoparticles (LNPs) face several unique challenges including stability during nebulization and penetration...
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Inhaled delivery of mRNA has the potential to treat a wide variety of diseases. However, nebulized mRNA lipid nanoparticles (LNPs) face several unique challenges including stability during nebulization and penetration through both cellular and extracellular barriers. Here we develop a combinatorial approach addressing these barriers. First, we observe that LNP formulations can be stabilized to resist nebulization-induced aggregation by altering the nebulization buffer to increase the LNP charge during nebulization, and by the addition of a branched polymeric excipient. Next, we synthesize a combinatorial library of ionizable, degradable lipids using reductive amination, and evaluate their delivery potential using fully differentiated air-liquid interface cultured primary lung epithelial cells. The final combination of ionizable lipid, charge-stabilized formulation and stability-enhancing excipient yields a significant improvement in lung mRNA delivery over current state-of-the-art LNPs and polymeric nanoparticles. Nebulized mRNA delivery has broad therapeutic potential but has proven challenging. Here, the authors report on a modified lipid nanoparticle with improved conditions to allow nebulization and demonstrate its application for delivering mRNA to the lungs.
SARS-CoV-2 employs its spike protein's receptor binding domain (RBD) to enter host cells. The RBD is constantly subjected to immune responses, while requiring efficient binding to host cell receptors for successfu...
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SARS-CoV-2 employs its spike protein's receptor binding domain (RBD) to enter host cells. The RBD is constantly subjected to immune responses, while requiring efficient binding to host cell receptors for successful infection. However, our understanding of how RBD's biophysical properties contribute to SARS-CoV-2's epidemiological fitness remains largely incomplete. Through a comprehensive approach, comprising large-scale sequence analysis of SARS-CoV-2 variants and the identification of a fitness function based on binding thermodynamics, we unravel the relationship between the biophysical properties of RBD variants and their contribution to viral fitness. We developed a biophysical model that uses statistical mechanics to map the molecular phenotype space, characterized by dissociation constants of RBD to ACE2, LY-CoV016, LY-CoV555, REGN10987, and S309, onto an epistatic fitness landscape. We validate our findings through experimentally measured and machine learning (ML) estimated binding affinities, coupled with infectivity data derived from population -level sequencing. Our analysis reveals that this model effectively predicts the fitness of novel RBD variants and can account for the epistatic interactions among mutations, including explaining the later reversal of Q493R. Our study sheds light on the impact of specific mutations on viral fitness and delivers a tool for predicting the future epidemiological trajectory of previously unseen or emerging low -frequency variants. These insights offer not only greater understanding of viral evolution but also potentially aid in guiding public health decisions in the battle against COVID-19 and future pandemics.
Background Sequencing of SARS-CoV-2 from rapid diagnostic tests (RDTs) can bolster viral genomic surveillance efforts;however, approaches to maximise and standardise pathogen genome recovery from RDTs remain underdeve...
Background Sequencing of SARS-CoV-2 from rapid diagnostic tests (RDTs) can bolster viral genomic surveillance efforts;however, approaches to maximise and standardise pathogen genome recovery from RDTs remain underdeveloped. We aimed to systematically optimise the elution of genetic material from RDT components and to evaluate the eff i cacy of RDT sequencing for outbreak investigation. Methods In this laboratory and cohort -based study we seeded RDTs with inactivated SARS-CoV-2 to optimise the elution of genomic material from RDT lateral fl ow strips. We measured the effect of changes in buffer type, time in buffer, and rotation on PCR cycle threshold (Ct) value. We recruited individuals older than 18 years residing in the greater Boston area, MA, USA, from July 18 to Nov 5, 2022, via email advertising to students and staff at harvard University, MA, USA, and via broad social media advertising. All individuals recruited were within 5 days of a positive diagnostic test for SARS-CoV-2;no other relevant exclusion criteria were applied. Each individual completed two RDTs and one PCR swab. On Dec 29, 2022, we also collected RDTs from a convenience sample of individuals who were positive for SARS-CoV-2 and associated with an outbreak at a senior housing facility in MA, USA. We extracted all returned PCR swabs and RDT components (ie, swab, strip, or buffer);samples with a Ct of less than 40 were subject to amplicon sequencing. We compared the eff i cacy of elution and sequencing across RDT brands and components and used RDT-derived sequences to infer transmission links within the outbreak at the senior housing facility. We conducted metagenomic sequencing of negative RDTs from symptomatic individuals living in the senior housing facility. Findings Neither elution duration of greater than 10 min nor rotation during elution impacted viral titres. Elution in Buffer AVL (Ct=31 . 4) and Tris-EDTA Buffer (Ct=30 . 8) were equivalent (p=0 . 34);AVL outperformed elution in lysis bu
Intracellular delivery of biomacromolecules is hampered by low efficiency and cytotoxicity. Here we report the development of elastin-based nanoparticles for therapeutic delivery (ENTER), a recombinant elastin-like po...
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Intracellular delivery of biomacromolecules is hampered by low efficiency and cytotoxicity. Here we report the development of elastin-based nanoparticles for therapeutic delivery (ENTER), a recombinant elastin-like polypeptide (ELP)-based delivery system for effective cytosolic delivery of biomacromolecules in vitro and in vivo. Through iterative design, we developed fourth-generation ELPs fused to cationic endosomal escape peptides (EEPs) that self-assemble into pH-responsive micellar nanoparticles and enable cytosolic entry of cargo following endocytic uptake. In silico screening of alpha-helical peptide libraries led to the discovery of an EEP (EEP13) with 48% improved protein delivery efficiency versus a benchmark peptide. Our lead ELP-EEP13 showed similar or superior performance compared to lipid-based transfection reagents in the delivery of mRNA-encoded, DNA-encoded and protein-form Cre recombinase and CRISPR gene editors as well as short interfering RNAs to multiple cell lines and primary cell types. Intranasal administration of ELP-EEP13 combined with Cre protein achieved efficient editing of lung epithelial cells in reporter mice.
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