Biology subjects

Harmon, C.

Publications and source records attributed to Harmon, C..

6 recordsLinked to original sources

bioRxiv2025

Convergent Signals Encode Persistent Memory of Resilient States

Caloric restriction reduces metabolic disease and associated comorbidities. Yet, the molecular mechanisms encoding cellular memory of these benefits remain unclear. Here, we use a functional genomics approach to integrate evolutionary cues, single-cell sequencing, and metabolomics, identifying convergent signals that encode epigenetic memory of adaptive states in visceral adipose tissue natural killer (NK) cells. Cross-species analysis shows that genomic hubs linked to human accelerated regions (HARs) are conserved and active during dietary restriction, forming transcriptional compartments that regulate oxidative stress response and DNA repair genes. Targeted screens and multimodal profiling across human data and mouse models reveal convergent signals needed for persistent adaptation: cooperative transcriptional regulators (NRF2, CIRBP, NR4A2) at key HAR-linked genomic hubs, innate immune mediators (IL15-IL2RB), and metabolic cofactors from linoleic acid oxidation. Activity of these convergent signals reduces DNA damage and methylation and enhances epigenetic plasticity and cytotoxic functions, thereby decreasing tissue fibrosis and senescence while maintaining both local and systemic metabolic plasticity. Mechanistically, linoleic acid metabolism supplies acetyl-CoA to sustain H3K27ac epigenetic marks that maintain coordinated repair and cytotoxic programs after programming. IL15-IL2RB signaling links tissue metabolic state to NK cell function for coherent adaptive responses. We show that engineering of NK cells with this multimodal programming leads to long-term preservation of therapeutic phenotypes in metabolic aging models, rescuing systemic dysfunction through damaged cells clearance and leptin sensitivity. Overall, these findings establish that convergent signals encode persistent cellular phenotypes linked to metabolic plasticity, suggesting design principles for engineering therapeutic memory of cell function. One-Sentence SummaryA multimodal approach reveals how dietary and evolutionary cues can be harnessed to engineer resilient phenotype memory.

immunology↗

bioRxiv2025

A multivalent mRNA-LNP therapeutic vaccine with broad cross-genotype immunogenicity elicits clearance of HBV infected hepatocytes

Chronic hepatitis B remains a major global health challenge, affecting over 254 million individuals and causing over 1 million deaths annually. Despite current antiviral therapies effectively suppressing viral replication, functional cure rates are low due to HBV-induced immune dysfunction and exhaustion. Therefore, new therapeutic approaches to achieve immune control of HBV infection are needed. Following the systematic evaluation of multiple HBV mRNA antigen designs, we developed mRNA-1965, a trivalent therapeutic mRNA vaccine encoding nanoparticle-displayed PreS1 and PreS2 domains of HBsAg to bypass the immune interference caused by HBV subviral particles, along with mutant forms of HBV Core and Polymerase. In HBV naive mice, mRNA-1965 immunization induced dose-dependent HBV-neutralizing antibodies and Th1-skewed CD4+ and IFN{gamma}+ CD8+ T cell responses to all three encoded HBV antigens. In non-human primates, mRNA-1965 elicited broad antibody and T cell responses across multiple HBV genotypes. Furthermore, vaccination with mRNA-1965 achieved a strong neutralizing antibody response and complete clearance of serum and liver HBV biomarkers in in an AAV-HBV mouse model with [~]100 IU/mL baseline HBsAg. Notably, combining mRNA-1965 with immune stimulatory co-modalities targeting PD-L1 and OX40 further enhanced therapeutic efficacy in mice with [~]1000 IU/mL baseline HBsAg. Clearance of HBV in AAV-HBV mice was associated with T cell response to mRNA-encoded antigens and with activation and differentiation of Core-specific CD8+ T cells. These findings support the potential of mRNA-1965 to promote a functional cure for chronic hepatitis B by overcoming immune dysfunction and subsequently enabling robust, functional immunity.

immunology↗

bioRxiv2025

mRNA-1273.251 and mRNA-1283.251 vaccines expressing SARS-CoV-2 variant LP.8.1 antigens broadly neutralize contemporary JN.1-lineage viruses

The continued evolution of the SARS-CoV-2 Omicron JN.1 lineage has led to the emergence of antigenically distinct subvariants including KP.2, KP.3, XEC, and LP.8.1, which became the dominant strains in the Americas and Europe by mid-2025. LP.8.1 was designated a Variant Under Monitoring by the WHO in January 2025 due to its potential to displace prior circulating variants. Informed by early growth modeling and antigenic analysis, we selected LP.8.1 as a candidate strain for the 2025-2026 vaccine season. Here, we describe the development of updated LP.8.1-matched mRNA vaccine compositions encoding either the full-length spike protein for mRNA-1273 (monovalent) or the membrane-anchored receptor-binding and N-terminal domains for the mRNA-1283 vaccine. Initial in vitro characterization, including structural analysis, demonstrated robust antigen expression and intact antigenic features. Immunogenicity of both vaccines were evaluated in murine models following immunization as either a primary series in naive animals or as a booster dose. LP.8.1-matched vaccines elicited strong neutralizing antibody responses against the homologous LP.8.1 strain and more recently emerging JN.1-lineage subvariants, including XFG and NB.1.8.1. Notably, the mRNA-1283 vaccine expressing LP.8.1 induced higher mean neutralization titers than the mRNA-1273 version across multiple variants. These data demonstrate the immunogenicity and breadth of both LP.8.1-based mRNA-1273 and mRNA-1283 vaccines in the context of ongoing JN.1 lineage evolution and support the selection of LP.8.1 as the updated vaccine antigen for the 2025-2026 season.

immunology↗

bioRxiv2024

Solvation Free Energy in Governing Equations for DNA Hybridization, Protein-Ligand Binding, and Protein Folding

This work examines the thermodynamics of model biomolecular interactions using a governing equation that accounts for the participation of bulk water in the balanced reaction. In the first example, the binding affinities of two model DNA duplexes, one of nine and one of ten base pairs in length, are measured and characterized by isothermal titration calorimetry as a function of concentration. The results indicate that the change in solvation free energy that accompanies duplex formation ({Delta}GS) is large and unfavorable. When normalized to the number of base pairs, the duplex with the larger number of G:C pairings yields the largest change in solvation free energy, {Delta}GS = +460 kcal/mol/base pair at 25 {degrees}C. A modelling study demonstrates how the solvation free energy alters the output of a typical titration experiment. Hybridization measurements are completed at four different temperatures, however a vant Hoff analysis of the data is complicated by the varying degree of intramolecular base stacking within each DNA strand as a function of temperature. The same thermodynamic framework is applied to a model protein- ligand interaction, the binding of ribonuclease A with the nucleotide inhibitor 3-UMP, and to a conformational equilibrium, the change in tertiary structure of -lactalbumin in molar guanidinium chloride solutions. The ribonuclease study yields a value of {Delta}GS = +160 kcal/mol, whereas the folding equilibrium yields {Delta}GS {approx} 0, an apparent characteristic of hydrophobic interactions. These examples complement previous applications of the governing equation to the interaction of smaller molecules and demonstrate the importance of solvation energy in biothermodynamics.

biochemistry↗

bioRxiv2018

Evolutionary exploitation of PD-L1 expression in hormone receptor positive breast cancer

Based on clinical data from hormone positive breast cancer patients, we determined that there is a potential tradeoff between reducing tumor burden and altering metastatic potential when administering combination therapy of aromatase inhibitors and immune checkpoint inhibitors. While hormone-deprivation therapies serve to reduce tumor size in the neoadjuvant setting pre-surgery, they may induce tumors to change expression patterns towards a metastatic phenotype. We used mathematical modeling to explore how the timing of the therapies affects tumor burden and metastatic potential with an eye toward developing a dynamic prognostic score and reducing both tumor size and risk of metastasis.

cancer biology↗

bioRxiv2018

The immune checkpoint kick start: Optimization of neoadjuvant combination therapy using game theory

An upcoming clinical trial at the Moffitt Cancer Center for women with stage 2/3 ER+breast cancer combines an aromatase inhibitor and a PD-L1 checkpoint inhibitor, and aims to lower a preoperative endocrine prognostic index (PEPI) that correlates with relapse-free survival. PEPI is fundamentally a static index, measured at the end of neoadjuvant therapy before surgery. We develop a mathematical model of the essential components of the PEPI score in order to identify successful combination therapy regimens that minimize both tumor burden and metastatic potential, based on time-dependent trade-offs in the system. We consider two molecular traits, CCR7 and PD-L1 which correlate with treatment response and increased metastatic risk. We use a matrix game model with the four phenotypic strategies to examine the frequency-dependent interactions of cancer cells. This game was embedded into an ecological model of tumor population growth dynamics. The resulting model predicts both evolutionary and ecological dynamics that track with changes in the PEPI score. We consider various treatment regimens based on combinations of the two therapies with drug holidays. By considering the trade off between tumor burden and metastatic potential, the optimal therapy plan was found to be a 1 month kick start of the immune checkpoint inhibitor followed by five months of continuous combination therapy. Relative to a protocol with both therapeutics given together from the start, this delayed regimen results in transient sub-optimal tumor regression while maintaining a phenotypic constitution that is more amenable to fast tumor regression for the final five months of therapy. The mathematical model provides a useful abstraction of clinical intuition, enabling hypothesis generation and testing of clinical assumptions.

cancer biology↗