Biology subjects

Henderson, R.

Publications and source records attributed to Henderson, R..

At least 19 recordsLinked to original sources

bioRxiv2026

B Cell Receptor Signaling Sets Boundaries for Selection of Broadly Neutralizing Antibody Functional Mutations

B cell signaling is required for germinal center (GC) selection and synergizes with T cell-help leading to differentiation into effector cells and a protective antibody response. Here, we studied the relationship between B cell signaling and the selection of functional mutations in a humanized mouse model of a CD4 binding-site specific HIV-1 broadly neutralizing antibody precursor. While BCR signaling increased with antigen affinity, immunization-induced frequency of a functional mutation was inversely related to affinity and favored a gain in association rate. Antigen-specific GC B cells and key mutation frequency were higher in the mid-affinity (0.5 - 5M) than in either the higher or lower affinity group, and were consistent with the significantly higher serum neutralization titers in the mid-range group. Our studies show that BCR signaling imposes boundaries (upper/lower) for selection of antibody functional mutations and support a "Goldilocks Zone" model that defines the favored BCR signaling strength for GC selection.

immunology↗

bioRxiv2026

Sequential HIV-1 fusion protein gates control the initiation of host cell entry

HIV-1 fusion with host cells is initiated upon engagement of the viral envelope (Env) protein by its receptors and co-receptors. Receptor-induced conformational changes in the Env ectodomain expose the fusion machinery and position the HIV-1 fusion peptide for release and transit to the host membrane. However, no allosteric rearrangements in the envelope receptor/co-receptor binding domain that could induce fusion peptide release have been identified, and the trigger for the structural cascade that brings the viral and host membranes together remains unknown. Here, we identified two sequential conformational gates that control fusion peptide release, thereby facilitating its transition to the host membrane. We show that destabilizing a clasp holding the fusion peptide proximal motif enhances fusion peptide release, and that a coupled downstream gate controls the release of the receptor-binding gp120 subunit. Single-particle cryo-EM structures, biased and unbiased atomistic simulations, and functional experiments reveal that this process is controlled by shifts in the angular orientation of the gp120 subunits, induced by the geometries required for receptor and co-receptor binding. These results show how HIV-1 senses contact with the host cell to initiate fusion, thereby permitting viral entry.

molecular biology↗

bioRxiv2026

Neural correlates of glioma progression using implanted neural interfaces

High-grade glioma is an incurable brain cancer with a median survival of approximately 14 months. Over the last 50 years, small improvements in patient outcomes have been overshadowed by significant progress in most other cancers. Yet, emerging research has revealed that neural circuits play an active and central role in driving glioma growth and proliferation, highlighting the nervous system as a promising avenue for both disease monitoring and therapeutic intervention. Here, we present a platform for chronically monitoring tumor progression using neural recordings in freely behaving mice with gliomas. Using this platform across multiple mouse strains and glioma models, we show that neural recordings can accurately track tumor progression in vivo. Cancer progression was consistently associated with elevated gamma-band neural activity in the tumor microenvironment across both adult glioblastoma (GBM) and pediatric diffuse intrinsic pontine glioma (DIPG) cancer models. Interestingly, lower frequency neural activity exhibited distinct, cell-line specific changes over time: GBM models exhibited decreases in low frequency neural activity whereas DIPG models exhibited increases over time. Finally, using machine learning models applied to chronic neural recordings from tumor-bearing mice treated with or without standard-of-care chemotherapy (temozolomide for GBM), we accurately predicted tumor burden as inferred through in vivo bioluminescence imaging. By fitting low-dimensional mathematical models to gamma-band neural trajectories, we could further predict individual tumor growth rates over a 5-week period with high accuracy. These results establish that pathological neural-tumor interactions can be harnessed to monitor glioma progression in vivo. Coupling this monitoring capability with therapeutic electrical stimulation in the same device could open up a new class of implantable, closed-loop neurotechnologies with the potential to transform glioma treatment.

neuroscience↗

bioRxiv2026

Germline-somatic residue synergy reshapes antibody encounter state pathways to enhance HIV 1 recognition

Antibodies initiate antigen recognition through short-lived encounter states. These states are structurally distinct from the bound state and allow an antibody to reach the epitope from diverse approach angles. We previously showed that encounter states enable broadly neutralizing HIV-1 antibodies to access protected epitopes, but how these states evolve during affinity maturation is unknown. Here, we defined encounter-state ensembles for two intermediates in a glycan-dependent antibody clonal lineage using extensive molecular dynamics simulations and Markov state modeling. Somatic mutations in the more mature member did not stabilize the bound state. Instead, they created early glycan-mediated interactions that reoriented the antibody during approach and markedly increased the association rate. This reorientation redistributed productive encounter states across a larger antigen surface. This expanded the antigen surface area over which collisions led to productive binding. The modified encounter state landscape positioned germline residues for conserved contacts and provided a kinetic route that naturally bypasses steric barriers at the epitope. Together, these results show that affinity maturation can proceed by reshaping encounter pathways rather than altering the final complex, revealing a generalizable mechanism by which somatic-germline synergy enhances antigen recognition.

immunology↗

bioRxiv2025

An integrated workflow for structural virology with a 100 keV electron microscope

Cryo-EM has revolutionized structural biology, especially for flexible and heterogeneous samples, although access to high end microscopes that enable these studies remains a bottleneck. While 300 keV microscopes have been the go-to for high-resolution structural determination, they are expensive and restricted to institutional and national facilities needing specialized expertise, with access falling far short of the demand. Here, we present the user-managed operation of a cheaper 100 keV electron microscope within a structural biology laboratory enabling close integration with protein production, biochemical and biophysical studies. We provide details and considerations for the installation of the microscope, its day-to-day maintenance, and operations. Using virus surface glycoproteins as case studies, we illustrate the workflow from grid screening, data collection, and data processing, and provide examples of data quality. This user-administered setup provides a training platform for researchers at all levels, with beginners in cryo-EM achieving proficiency to independently operate the microscope within a month of regular use and training. We have demonstrated routine high-quality low-resolution reconstructions using a Ceta CMOS camera and high-resolution reconstructions enabling building of atomic models using a Falcon C direct detector. While there are several examples of facilities that manage cryo-EM and individual laboratories leveraging cryo-EM, we provide here the first demonstration of a modern group independently doing both successfully, something that has been talked about frequently but rarely seen.

biochemistry↗

bioRxiv2025

Measurement of atomic scattering factors by cryo-electron microscopy

Determination of specimen structure from cryo-electron microscopy (cryo-EM) experiments relies on an accurate model of the electrostatic potential of the specimen. For biological macromolecules, the potential is strongly influenced by the presence of chemical bonds between atoms, a fact unaccounted for by models of electron scattering that are currently standard in the field. We propose a Bayesian approach to the estimation of atomic scattering factors which incorporates the effect of the molecular environment while remaining fast, interpretable and transferable between molecules. Our algorithm infers atomic scattering factors directly from maps of the electrostatic potential determined by cryo-EM single particle analysis, bypassing the need for computationally-intensive theoretical calculations. The algorithm is used to infer empirical scattering factors from high-resolution reconstructions of catalase enzymes. To illustrate its broad applicability, the algorithm is also applied to a training set of publicly-available cryo-EM data. The empirical scattering factors show improved agreement with a test set of cryo-EM reconstructions. The predictions are further validated by comparison with magnetic susceptibility values of organic compounds, as well as by application to the refinement of atomic models. Significance StatementUnderstanding the structure of biomolecules is key to explaining their function. Cryo-electron microscopy is a method for reconstructing the electrostatic potential distribution of a biological macro-molecule, a quantity which contains information about atomic positions and the redistribution of charge due to chemical bonding. These factors should be modelled when inferring the structure of the molecule from its electrostatic potential. We develop an improved model of the potential that takes into account chemical bonding while remaining computationally tractable. The parameters of the model are inferred from a selection of cryo-electron microscopy datasets using Bayesian methods.

biophysics↗

bioRxiv2025

ESPWA: a deep learning-enabled tool for precision-based use of endocrine therapy in resource-limited settings

Immunohistochemistry for estrogen receptor (ER) expression is often unavailable in low-and-middle-income countries (LMICs), leading to empiric use of endocrine therapy (ET) and unnecessary toxicity in ER-negative patients. To address this unmet need, we developed ESPWA, a deep-learning model trained on 3448 H&E slides and tissue-matched ER status from breast cancer patients treated at Zanmi Lasante (ZL), Haiti. A model trained on The Cancer Genome Atlas (TCGA) exhibited substantial domain shift when applied to the ZL cohort, with AUROCs dropping from 0.846 on TCGA cross-validation to 0.671 on the ZL cohort. In contrast, ESPWA demonstrated improved performance on ZL cross-validation (AUROC=0.790; p=0.005). In an independent test set of 134 Haitian patients with parallel slides prepared and scanned in Mirebalais Hospital (Haiti) and Brigham and Womens Hospital, ESPWA was robust to variations in slide preparation, quality, and scanners, achieving AUROCs of 0.794 on BWH-prepared WSIs and 0.805 on Mirebalais-prepared WSIs. Prospective studies using ESPWA are underway in sub-Saharan Africa to evaluate its utility in informing precision-based use of ET.

cancer biology↗

bioRxiv2025

A field-focused systems approach reveals mRNA covalent modifications linked to sorghum growth and development under drought stress

RNA Covalent Modifications (RCMs) are post-transcriptional chemical alterations that influence RNA stability and translation efficiency, thus play critical roles in eukaryotic growth and development. However, their role in regulating plant performance under abiotic stress remain largely unexplored. Here, we integrated multi-omics data in six Sorghum bicolor accessions under water-limiting conditions in the field to explore the relationship between RCMs and drought response. Within a stress and photosynthesis-associated gene co-expression module, we identified SbDUS2, a member of family of enzymes, conserved across eukaryotes, which catalyzes the reduction of uracil to dihydrouridine (DHU) on RNA molecules. DHU-modified transcripts in this module were enriched for photosynthetic functions and showed strong correlation with photosynthetic traits. To elucidate the function of this RCM, we characterized loss of function dus2 mutants in the genetic model, Arabidopsis thaliana. Under control conditions, these DHU-deficient mutants exhibited impaired germination and delayed development. Furthermore, when exposed to heat or water-limiting conditions, these mutants showed significantly reduced net CO2 assimilation and survival. Using multiple transcriptome-wide RNA stability assays, we demonstrated that transcripts associated with lower DHU level in a dus2 background generally exhibited increased stability compared to Col-0 controls. Particularly, lack of DUS2 led to the hyperstability of photosynthesis-related transcripts, impeding their turnover and likely preventing proper photosynthetic acclimation during stress. We propose a model based on these data where DHU acts as a critical post-transcriptional regulator marking mRNAs for rapid turnover under stress, highlighting an overlooked regulatory layer contributing to plant resilience.

plant biology↗

bioRxiv2024

Conformational trajectory of the HIV-1 fusion peptide during CD4-induced envelope opening

The hydrophobic fusion peptide (FP), a critical component of the HIV-1 entry machinery, is located at the N terminal stretch of the envelope (Env) gp41 subunit1-3. The receptor-binding gp120 subunit of Env forms a heterodimer with gp41 and assembles into a trimer, in which FP is accessible for antibody binding3. Env conformational changes or "opening" that follow receptor binding result in FP relocating to a newly formed interprotomer pocket at the gp41-gp120 interface where it is sterically inaccessible to antibody4. The mechanistic steps connecting the entry-related transition of antibody accessible-to-inaccessible FP configurations remain unresolved. Here, using SOSIP-stabilized Env ectodomains5, we visualized atomic-level details of a functional entry intermediate, where partially open Env was bound to receptor CD4, co-receptor mimetic antibody 17b, and FP-targeting antibody VRC34.01, demonstrating that FP remains antibody accessible despite substantial receptor-induced Env opening. We determined a series of structures delineating stepwise opening of Env from its closed state to a newly resolved intermediate and defining downstream re-organizations of the gp120-gp41 interface that ultimately resulted in FP burial in an antibody-inaccessible configuration. Our studies improve our understanding of HIV-1 entry and provide information on entry-related conformation reorganization of a key site of HIV vulnerability to neutralizing antibody.

microbiology↗

bioRxiv2024

SARS-CoV-2 Omicron lineage XBB spike structures, conformations, antigenicity, and receptor recognition

A recombinant lineage of the SARS-CoV-2 Omicron variant, named XBB, appeared in late 2022 and evolved descendants that successively swept local and global populations. XBB lineage members were noted for their improved immune evasion and transmissibility. Here, we determine cryo-EM structures of XBB.1.5, XBB.1.16, EG.5 and EG.5.1 spike (S) ectodomains to reveal reinforced 3-RBD-down receptor inaccessible closed states mediated by interprotomer receptor binding domain (RBD) interactions previously observed in BA.1 and BA.2. Improved XBB.1.5 and XBB.1.16 RBD stability compensated for stability loss caused by early Omicron mutations, while the F456L substitution reduced EG.5 RBD stability. S1 subunit mutations had long-range impacts on conformation and epitope presentation in the S2 subunit. Our results reveal continued S protein evolution via simultaneous optimization of multiple parameters including stability, receptor binding and immune evasion, and the dramatic effects of relatively few residue substitutions in altering the S protein conformational landscape.

biochemistry↗

bioRxiv2023

Broadly neutralizing antibody induction by non-stabilized SARS-CoV-2 Spike mRNA vaccination in nonhuman primates

Immunization with mRNA or viral vectors encoding spike with diproline substitutions (S-2P) has provided protective immunity against severe COVID-19 disease. How immunization with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) spike elicits neutralizing antibodies (nAbs) against difficult-to-neutralize variants of concern (VOCs) remains an area of great interest. Here, we compare immunization of macaques with mRNA vaccines expressing ancestral spike either including or lacking diproline substitutions, and show the diproline substitutions were not required for protection against SARS-CoV-2 challenge or induction of broadly neutralizing B cell lineages. One group of nAbs elicited by the ancestral spike lacking diproline substitutions targeted the outer face of the receptor binding domain (RBD), neutralized all tested SARS-CoV-2 VOCs including Omicron XBB.1.5, but lacked cross-Sarbecovirus neutralization. Structural analysis showed that the macaque broad SARS-CoV-2 VOC nAbs bound to the same epitope as a human broad SARS-CoV-2 VOC nAb, DH1193. Vaccine-induced antibodies that targeted the RBD inner face neutralized multiple Sarbecoviruses, protected mice from bat CoV RsSHC014 challenge, but lacked Omicron variant neutralization. Thus, ancestral SARS-CoV-2 spike lacking proline substitutions encoded by nucleoside-modified mRNA can induce B cell lineages binding to distinct RBD sites that either broadly neutralize animal and human Sarbecoviruses or recent Omicron VOCs. One Sentence SummaryNon-stabilized SARS-CoV-2 Spike mRNA vaccination activated B cells that target either conserved epitopes on SARS-CoV-2 Omicron variants of concern, or cross-neutralizing epitopes on pre-emergent Sarbecoviruses.

immunology↗

bioRxiv2023

Engineering immunogens that select for specific mutations in HIV broadly neutralizing antibodies

Vaccine development targeting rapidly evolving pathogens such as HIV-1 requires induction of broadly neutralizing antibodies (bnAbs) with conserved paratopes and mutations, and, in some cases, the same Ig-heavy chains. The current trial-and-error search for immunogen modifications that improve selection for specific bnAb mutations is imprecise. To precisely engineer bnAb boosting immunogens, we used molecular dynamics simulations to examine encounter states that form when antibodies collide with the HIV-1 Envelope (Env). By mapping how bnAbs use encounter states to find their bound states, we identified Env mutations that were predicted to select for specific antibody mutations in two HIV-1 bnAb B cell lineages. The Env mutations encoded antibody affinity gains and selected for desired antibody mutations in vivo. These results demonstrate proof-of-concept that Env immunogens can be designed to directly select for specific antibody mutations at residue-level precision by vaccination, thus demonstrating the feasibility of sequential bnAb-inducing HIV-1 vaccine design.

immunology↗

bioRxiv2023

Microsecond dynamics control the HIV-1 envelope conformation

The HIV-1 Envelope (Env) glycoprotein facilitates host cell fusion through a complex series of receptor-induced structural changes. Although significant progress has been made in understanding the structures of various Env conformations and transition intermediates that occur within the millisecond timescale, faster transitions in the microsecond timescale have not yet been observed. In this study, we employed time-resolved, temperature-jump small angle X- ray scattering to monitor structural rearrangements in an HIV-1 Env ectodomain construct with microsecond precision. We detected a transition correlated with Env opening that occurs in the hundreds of microseconds range and another more rapid transition that preceded this opening. Model fitting indicated that the early rapid transition involved an order-to-disorder transition in the trimer apex loop contacts, suggesting that conventional conformation-locking design strategies that target the allosteric machinery may be ineffective in preventing this movement. Utilizing this information, we engineered an envelope that locks the apex loop contacts to the adjacent protomer. This modification resulted in significant angle-of-approach shifts in the interaction of a neutralizing antibody. Our findings imply that blocking the intermediate state could be crucial for inducing antibodies with the appropriate bound state orientation through vaccination.

biophysics↗

bioRxiv2023

Vaccine induction of CD4-mimicking broadly neutralizing antibody precursors in macaques

The CD4 binding site (CD4bs) is a conserved epitope on HIV-1 envelope (Env) that can be targeted by protective broadly neutralizing antibodies (bnAbs). HIV-1 vaccines have not elicited CD4bs bnAbs for many reasons, including the CD4bs is occluded by glycans, immunogen expansion of appropriate naive B cells, and selection of functional antibody mutations. Here, we demonstrate immunization of macaques with a CD4bs-targeting immunogen elicits neutralizing bnAb precursors with structural and genetic features of CD4-mimicking bnAbs. Structures of the CD4bs nAbs bound to HIV-1 Env demonstrated binding angles similar to human bnAbs and heavy chain second complementarity determining region-dependent binding characteristic of all known human CD4-mimicking bnAbs. Macaque nAbs were derived from variable and joining gene segments orthologous to the genes of human VH1-46-class bnAbs. This vaccine study initiated the B cells from which derive CD4bs bnAbs in primates, accomplishing the key first step in development of an effective HIV-1 vaccine.

immunology↗

bioRxiv2022

Longitudinal monitoring of maternal care and maternal neglect

Parental care is required for offspring survival, because infants require nearly-continual oversight for extensive periods. Parents must balance caretaking with their own survival, and benefit from help provided by other experienced adults. We built a system for 24/7 long-term monitoring of wild-type or oxytocin receptor knockout (OXTR-KO) mouse mothers ( dams) over litters. Some wild-type dams had high litter survival rates, but others consistently lost pups due to neglect and hypothermia. Maternal caretaking in low-pup-survival dams improved after co-housing with an experienced dam and litter, from reorganized maternal behavior including increased nest-building. In contrast, singly-housed OXTR-KOs died in childbirth and pups died due to prolonged parturition. Co-housing with a lactating female prevented OXTR-KO maternal-infant mortality, because the other female acted as a midwife by removing and cleaning pups from the pregnant dam. Thus for single mothers that continually lose litters or die in labor, maternal-infant survival is enhanced by experienced helpers.

neuroscience↗

bioRxiv2022

Mutation-Guided Vaccine Design: A Strategy for Developing Boosting Immunogens for HIV Broadly Neutralizing Antibody Induction

A major goal of HIV-1 vaccine development is induction of broadly neutralizing antibodies (bnAbs). While success has been achieved in initiating bnAb B cell lineages, design of boosting immunogens that select for bnAb B cell receptors with improbable mutations required for bnAb affinity maturation remains difficult. Here we demonstrate a process for designing boosting immunogens for a V3-glycan bnAb B cell lineage. The immunogens induced affinity-matured antibodies by selecting for functional improbable mutations in bnAb precursor knock-in mice. Moreover, we show similar success in prime and boosting with nucleoside-modified mRNA-encoded HIV-1 envelope trimer immunogens, with improved selection by mRNA immunogens of improbable mutations required for bnAb binding to key envelope glycans. These results demonstrate the ability of both protein and mRNA prime-boost immunogens for selection of rare B cell lineage intermediates with neutralizing breadth after bnAb precursor expansion, a key proof-of concept and milestone towards development of an HIV vaccine. One-Sentence SummaryA vaccine strategy for selecting key rare antibody mutations is shown to induce HIV broadly neutralizing antibodies in mice.

immunology↗

bioRxiv2022

Structural basis for breadth development in a HIV-1 neutralizing antibody

Antibody affinity maturation enables adaptive immune responses to a wide range of pathogens. In some individuals broadly neutralizing antibodies develop to recognize rapidly mutating pathogens with extensive sequence diversity. Vaccine design for pathogens such as HIV-1 and influenza have therefore focused on recapitulating the natural affinity maturation process. Here, we determined structures of antibodies in complex with HIV-1 Envelope for all observed members and ancestral states of a broadly neutralizing HIV-1 antibody clonal B cell lineage. These structures track the development of neutralization breadth from the unmutated common ancestor and define affinity maturation at high spatial resolution. By elucidating contacts mediated by key mutations at different stages of antibody development we have identified sites on the epitope-paratope interface that are the focus of affinity optimization. Thus, our results identify bottlenecks on the path to natural affinity maturation and reveal solutions for these that will inform immunogen design aimed at eliciting a broadly neutralizing immune response by vaccination. SummarySomatic hypermutation drives affinity maturation of germline-encoded antibodies leading to the development of their pathogen neutralization function1. Rational vaccine design efforts that aim to recapitulate affinity maturation rely on information from antibodies elicited and matured during natural infection. High-throughput next generation sequencing and methods for tracing antibody development have allowed close monitoring of the antibody maturation process. Since maturation involves both affinity-enhancing and affinity-independent diversification, the precise effect of each observed mutation, their role in enhancing affinity to antigens, and the order in which the mutations accumulated are often unclear. These gaps in knowledge most acutely hinder efforts directed at difficult targets such as pan-HIV, pan-Influenza, and pan-Coronavirus vaccines. In HIV-1 infection, antibody maturation over several years is required to achieve neutralization breadth. Here, we determined structures of antibodies in complex with HIV-1 Envelope trimers for all observed members and ancestral states of a broadly neutralizing HIV-1 antibody clone to examine affinity maturation as neutralization breadth developed from the unmutated common ancestor. Structural determination of epitope-paratope interfaces revealed details of the contacts evolving over a timescale of several years. Structures along different branches of the clonal lineage elucidated differences in the branch that led to broad neutralization versus off-track paths that culminated in sub-optimal neutralization breadth. We further determined structures of the evolving Envelope revealing details of the virus-antibody co-evolution through visualization of how the virus constructs barriers to evade antibody-mediated neutralization and the mechanisms by which the developing antibody clone circumvents these barriers. Together, our structures provide a detailed time-resolved imagery of the affinity maturation process through atomic level descriptions of virus-antibody co-evolution leading to broad HIV neutralization. While the findings from our studies have direct relevance to HIV-1, the principles of affinity optimization and breadth development elucidated in our study should have broad relevance to other pathogens.

immunology↗

bioRxiv2022

Replenishing the malaria drug discovery pipeline: Screening and hit evaluation of the MMV Hit Generation Library 1 (HGL1) against asexual blood stage Plasmodium falciparum, using a nano luciferase reporter read-out

A central challenge of antimalarial therapy is the emergence of resistance to the components of artemisinin-based combination therapies (ACTs) and the urgent need for new drugs acting through novel mechanism of action. Over the last decade, compounds identified in phenotypic high throughput screens (HTS) have provided the starting point for six candidate drugs currently in the Medicines for Malaria Venture (MMV) clinical development portfolio. However, the published screening data which provided much of the new chemical matter for malaria drug discovery projects have been extensively mined. Here we present a new screening and selection cascade for generation of hit compounds active against the blood stage of Plasmodium falciparum. In addition, we validate our approach by testing a library of 141,786 compounds not reported earlier as being tested against malaria. The Hit Generation Library 1 (HGL1) was designed to maximise the chemical diversity and novelty of compounds with physicochemical properties associated with potential for further development. A robust HTS cascade containing orthogonal efficacy and cytotoxicity assays, including a newly developed and validated nanoluciferase-based assay was used to profile the compounds. 75 compounds (Screening Active hit rate of 0.05%) were identified meeting our stringent selection criteria of potency in drug sensitive (NF54) and drug resistant (Dd2) parasite strains (IC50 [≤] 2 {micro}M), rapid speed of action and cell viability in HepG2 cells (IC50 [≥] 10 {micro}M). Following further profiling, 33 compounds were identified that meet the MMV Confirmed Active profile and are high quality starting points for new antimalarial drug discovery projects.

microbiology↗