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Biology subjects

Adams, C.

Publications and source records attributed to Adams, C..

At least 19 recordsLinked to original sources

Tamoxifen and Doxorubicin Synergistically Target Estrogen Receptor beta-Mutant p53-p73 Axis, a Therapeutically Actionable Vulnerability in Triple Negative Breast Cancer

Current therapeutic regimens for triple negative breast cancer (TNBC) are not very effective in majority of patients and have serious adverse effects. Tamoxifen (Tam), a selective estrogen receptor modulator (SERM), routinely used to treat estrogen receptor alpha-positive breast cancer, has traditionally not been considered for TNBC therapy because it lacks expression of ER alpha, the canonical target of Tam. Challenging this conventional clinical paradigm, we have demonstrated, using genetic and pharmacological approaches, that Tam synergizes with DNA-damaging agent doxorubicin (Doxo) to increase cell death by both apoptosis and ferroptosis leading to growth inhibition of TNBC CDXs and PDXs expressing mutant p53. Mechanistically, these responses are dependent on ER beta-mutant p53 interaction enhanced by Tam, thereby disrupting p73-mutant p53 complex resulting in reactivation of p73 and transcriptomic reprogramming converging on apoptosis and ferroptosis. These studies demonstrate the potential for repurposing Tam with Doxo as an effective and safe therapeutic strategy to treat molecularly stratified TNBC.

cancer biology↗

Deep Learning-based Modeling Enhances Efficacy of Natural Ligand CAR Binders Targeting CD70

CD70 is well-recognized as a promising "pan-cancer: chimeric antigen receptor (CAR) T-cell target. Prior work has shown that a "natural ligand" (NL)-based CAR targeting CD70, employing its physiological interaction partner CD27, may have therapeutic advantages over antibody-based CARs. Yet while antibody-based CARs are routinely optimized by affinity maturation of their scFv, whether the binding sequence of an NL CAR can be engineered to improve its function remains unexplored. Here, we combined deep learning with physics-based modeling to redesign residues at the CD27:CD70 interface, identifying a CD27 variant, "N88A", which enhances the efficacy of CD70-targeting CAR T-cells across models of acute myeloid leukemia, multiple myeloma, and renal cell carcinoma. Biophysical approaches, including molecular dynamics simulations, support a mechanism of increased binder conformational freedom underlying potency enhancement. Our work presents CD27N88A CAR T-cells as a promising new therapeutic option and proposes that computational modeling could be applied to enhance efficacy of other NL-based immunotherapies.

cancer biology↗

Scalable mass-spectrometry-based molecular phylogeny with TreeMS2

Molecular phylogeny is a well-established method for inferring evolutionary relationships from DNA and RNA sequences. Here, we extend this concept beyond genetic information by applying phylogeny-like analysis to proteomic and metabolomic mass spectrometry data, capturing relationships based on the realized molecular phenotype. The resulting phenotype-derived trees can be directly compared with conventional genetic-based trees to identify where molecular phenotypes reflect evolutionary history and where they diverge due to functional adaptation, regulation, or environmental influence. To enable this analysis, we introduce TreeMS2, a computational tool that constructs similarity matrices by directly comparing tandem mass spectrometry (MS/MS) spectra between samples. By bypassing spectrum annotation, TreeMS2 enables rapid, unbiased comparisons. Across diverse datasets, TreeMS2 reconstructs biologically meaningful relationships. In proteomics, phenotype-derived trees recapitulate established taxonomy, with deviations pinpointing sample handling errors. In single-cell proteomics our method distinguishes cell types despite sparse and noisy measurements and in metabolomics it resolves major biochemical divisions and fine-scale compositional structure. Together, these results establish TreeMS2 as a scalable, annotation-independent framework for deriving molecular relationships from raw MS/MS data.

bioinformatics↗

A Brainwide Atlas of Synaptic Nanoarchitecture Across the Mouse Lifespan

How biological complexity emerges from the ordered assembly of molecular building blocks into supramolecular systems remains a central question, particularly in the mammalian brain with its vast synaptic diversity. We introduce NanoSYNMAP, a genetic, optical, and computational platform that integrates FRET with synaptome mapping to quantify nanoscale proximity of proteins in individual synapses brain-wide. We generate the first brain atlas of synaptic nanoarchitecture, based on the proximity of postsynaptic MAGUK supercomplexes. This reveals a molecular logic in which spacing of supramolecular assemblies specifies nanoscale architecture that organizes the global synaptome architecture. Nanoarchitecture varies across brain regions, differentiates during postnatal development, and remodels with aging. Supercomplex proximity reflects scaffold abundance, nanodomain organization, and competitive interactions among MAGUK assemblies. Deletion of a neuropsychiatric risk gene triggers widespread reorganization of nanoscale architecture. These findings establish molecular proximity as a fundamental scalable dimension of synapse diversity in health and disease.

neuroscience↗

A small molecule PTER-selective inhibitor reduces food intake and body weight

PTER (phosphotriesterase-related) is an amidohydrolase that mediates catabolism of the anorexigenic taurine metabolite N-acetyltaurine. However, the structural basis of PTER ligand binding and catalysis remain unknown, limiting our ability to harness this pathway therapeutically. Here we solve crystal structures of a eukaryotic PTER in apo and product-bound forms. These structures uncover an unexpected pocket homology between PTER and histone deacetylase (HDAC) enzymes. We exploit this similarity to engineer a first-in-class substrate-competitive PTER inhibitor called PTERi with nanomolar potency and >100-fold selectivity for PTER over HDACs in vitro. Administration of PTERi to diet-induced obese mice reduces feeding, enhances GLP1-RA (glucagon like peptide 1 receptor agonist)-induced weight loss, and prevents weight regain after GLP1-RA discontinuation. The structure of PTER connects histone and metabolite deacetylation into a parallel conceptual framework and enables proof-of-concept data for pharmacological inhibition of PTER in obesity.

biochemistry↗

Construction of a randomly barcoded insertional mutant library in the filamentous fungus Trichoderma atroviride

Filamentous fungi play key roles in ecosystems, agriculture, biotechnology, symbiosis, and disease, yet the large-scale characterization of gene function in these organisms remains limited by low transformation efficiencies and their multinucleate, syncytial cells, which complicate high-throughput screening strategies. To address the challenge of high-throughput screening in filamentous fungi, we developed methods to construct a genome-wide barcoded insertional mutant library in Trichoderma atroviride, a filamentous fungus widely used as a biocontrol agent against bacterial and fungal plant pathogens. Our strategy leveraged randomly barcoded transfer DNA insertions from plasmid libraries containing hundreds of millions of unique DNA barcodes and a broad host-range drug resistance marker delivered via Agrobacterium tumefaciens into T. atroviride. By optimizing transformation conditions, we achieved up to 600 independent transformants per infection event, resulting in a library of over 31,000 mapped insertions disrupting 7,104 of the 11,863 predicted genes in the T. atroviride genome. This resource establishes a scalable platform for high-throughput functional genomics in filamentous fungi, enabling both fundamental investigations of fungal biology and engineering approaches toward improved medical applications, biotechnology, and sustainable agriculture.

systems biology↗

A critical role for brain nutrition in the life-history decisions of a partially migratory fish

The role played by omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) in life-history polymorphisms in partially migratory species remains poorly understood. Yet, brain development is highly dependent upon nutrition, particularly the supply of n-3 LC-PUFA, derived from diet or internally converted from their shorter-chain precursors, and the fitness of animals may be shaped by cognitive performance, including effective spatial navigation required by migration. We investigated juveniles of a wild polymorphic population of brown trout, Salmo trutta, with three distinct migratory ecotypes, at the point of first outward migration. Using a combination of fatty acid contents, compound-specific stable isotope analysis, and liver transcriptomics, we found that non-migrants compensated for dietary deficiency by biosynthesising n-3 LC-PUFA from precursor molecules and routing them to cell membranes to a greater extent than did migrants. These findings highlight contrasting intake and processing between migratory and non-migratory life histories of nutrients associated with brain development.

ecology↗

Inhibition of MLLT1 limits growth of MLL-AF4 leukaemias without killing healthy haematopoietic stem cells

A major challenge in cancer therapeutics has been the identification of targets that are selectively toxic to cancer cells while displaying limited effects on healthy counterparts. Toxicities related to blood production from haematopoietic stem and progenitor cells (HSPCs) can be particularly problematic and result in patient morbidity and mortality. Within haematological malignancies, therapy response rates and patient survival vary widely between cancer subtypes, with leukaemias driven by the MLL-AF4 fusion protein associated with poor prognosis. MLLT1 has been recently identified as a key potential target in acute myeloid leukaemia. Here we evaluated a panel of leukaemia cell lines and healthy HSPCs for their sensitivity to the MLLT1 inhibitor SGC-iMLLT. We found that SGC-iMLLT strongly inhibited MLL-AF4-driven leukaemia growth in vitro and in vivo. By contrast, SGC-iMLLT did not alter in vitro colony forming potential of human HSPCs or affect long-term in vivo function of mouse HSPCs. These results suggest that SGC-iMLLT may have a promising therapeutic window in the treatment of MLL-AF4-driven leukaemias, and that further clinical development is warranted.

cancer biology↗

Molecular basis for multidrug efflux by an anaerobic RND transporter

Bacteria can resist antibiotics and toxic substances within demanding ecological settings, such as low oxygen, extreme acid, and during nutrient starvation. MdtEF, a proton motive force-driven efflux pump from the resistance-nodulation-cell division (RND) superfamily, is upregulated in these conditions but its molecular mechanism is unknown. Here, we report cryo-electron microscopy structures of Escherichia coli multidrug transporter MdtF within native-lipid nanodiscs, including a single-point mutant with an altered multidrug phenotype and associated substrate-bound form. We reveal that drug binding domain and channel conformational plasticity likely governs promiscuous substrate specificity, analogous to its closely related, constitutively expressed counterpart, AcrB. Whereas we discover distinct transmembrane state transitions within MdtF, which create a more engaged proton relay network, altered drug transport allostery and an acid-responsive increase in efflux efficiency. Physiologically, this provides means of xenobiotic and metabolite disposal within remodelled cell membranes that presage encounters with acid stresses, as endured in the gastrointestinal tract.

biochemistry↗

Adult killifish exposure to crude oil perturbs embryonic gene expression and larval morphology in first- and second-generation offspring

Exposures to environmental toxicants can have both immediate and long-term impacts, including those that persist into the next generation. Using Gulf killifish (Fundulus grandis), we tested whether adult progenitor exposure to crude oil caused perturbations to larval morphology and embryonic genome-wide gene expression in their first- and second-generation descendants raised in clean water. We also tracked responses of additional direct oil exposures in the F1 and F2 embryos. Exposure to oil in progenitor fish caused altered larval morphology in F1 and F2 descendants. Some perturbations were enhanced by additional oil exposure in lineages with progenitors that had been exposed to oil. Progenitor exposures altered embryonic gene expression in F1 and F2 descendants, implicating impacts on neurological and cardiovascular systems. Molecular responses to progenitor exposure were distinct between F1 and F2 offspring, suggesting complex interactions between mechanisms that contribute to the transgenerational transfer of information. In contrast, molecular responses to additional direct oil exposures during early-life development were highly conserved between generations and between progenitor exposure treatments. We conclude that exposure to crude oil causes developmental perturbations that propagate at least two generations, and we present additional hypotheses about underlying molecular mechanisms and emergent health consequences. SYNOPSISThis study shows that exposure of adult fish to crude oil perturbs development and gene expression in offspring and grand-offspring, thereby extending the timeframe necessary to consider ecotoxicological risk.

pharmacology and toxicology↗

HIV-1 Rebound Virus Consists of a Small Number of Lineages That Entered the Reservoir Close to ART Initiation

HIV-1 persists as a latent reservoir during suppressive antiretroviral therapy (ART). Viral rebound occurs upon ART interruption, posing a challenge to cure efforts. Characterizing viral populations fuelling rebound is imperative to curing HIV-1. We used longitudinal samples collected pretherapy from women in the CAPRISA 002 cohort to create an evolutionary time- line to determine the pretherapy timepoint when the rebound virus originally entered the long- lived reservoir. Participants (N=10) were untreated for an average of 5 years then on ART for an average of 2 years before viral rebound (defined as >1000 RNA copies/ml). env sequences were used to characterize the longitudinal pre-ART evolving viral RNA population, the proviral DNA reservoir during ART, and viral RNA in the plasma during rebound. For each participant, between 1 and 3 major viral lineages were identified in the plasma during rebound. A total of 20 rebound virus lineages were examined for the 10 participants, and 19 were found to have entered the reservoir around the time of therapy initiation. The one lineage estimated to enter the reservoir more than a year before therapy was observed in a participant who was untreated for more than 8 years, yet retained moderate CD4 T cell counts. Analysis of the viral DNA reservoir, from which the rebound viruses emanated, revealed that while 95% of rebounding lineages dated to the year before ART initiation, only 61% of unique proviruses dated to that time period. Strikingly, for three participants with DNA reservoirs dominated by viruses from earlier in untreated infection, only 33% of unique proviruses dated to the year before ART initiation, yet 83% of rebounding lineages dated to that time. Our results show that rebound virus almost exclusively comes from the portion of the latent reservoir that formed around the time of therapy initiation, even when the reservoir is composed of diverse sequences from across the pre-ART time period. Author SummaryHIV-1 is maintained in a long-lived reservoir during suppressive therapy. Virus rebounds if therapy is discontinued. We found that in most cases rebound virus comes from a pool of viral sequences that entered the long-lived reservoir around the time of therapy initiation. While the viral DNA reservoir is on average also skewed toward sequences replicating around the time of therapy initiation, the rebound virus almost exclusively comes from this portion of the latent reservoir, even when the reservoir contained proviruses from much earlier in untreated infection. Thus, we hypothesize that there are features of the viruses forming the latent reservoir around the time of therapy initiation, or features of the host at that time, that select these viruses as initiators of rebound during therapy discontinuation.

microbiology↗

3D super-resolution imaging of PSD95 reveals an abundance of diffuse protein supercomplexes in the mouse brain

PSD95 is an abundant scaffolding protein that assembles multiprotein complexes controlling synaptic physiology and behavior. Confocal microscopy has previously shown that PSD95 is enriched in the postsynaptic terminals of excitatory synapses and 2D super-resolution microscopy further revealed that it forms nanoclusters. In this study, we utilized 3D super-resolution microscopy to examine the nanoarchitecture of PSD95 in the mouse brain, characterizing over 8 million molecules. While we were able to identify structural subtypes previously reported, imaging in 3D allowed us to classify these with higher accuracy. Furthermore, 3D super-resolution microscopy enabled the quantification of protein levels, revealing an abundance of PSD95 molecules existed outside of synapses as a diffuse population of supercomplexes, containing multiple copies of PSD95. Further analysis of the supercomplexes containing two units identified two populations: one that had PSD95 molecules separated by 39 {+/-} 2 nm, and a second with a separation of 94 {+/-} 27 nm. These results suggest that PSD95 supercomplexes containing multiple protein copies assemble outside the synapse and then integrate into the synapse to form a supramolecular nanocluster architecture.

biophysics↗

Rare twin cysteine residues in the HIV-1 envelope variable region 1 link to neutralization escape and breadth development

The identification of HIV-1 Envelope glycoprotein (Env) traits associated with development of neutralization cross-reactivity in natural infection is critical for vaccine design. Here we describe the presence of additional Cysteine (Cys) residues in V1 that are enriched among people with elite neutralization breadth. Using >65,000 V1 sequences from the CATNAP database, the AMP trials and three large longitudinal HIV infection cohorts, the SHCS, ZPHI and CAPRISA studies, we show that Env variants with extra V1 Cys are present at low levels throughout infection and fluctuate in frequency over time within participants. We demonstrate an independent association of extra V1 Cys with elite plasma neutralization, and a strong preference for two versus one extra Cys, suggesting certain Envs introduce an additional disulfide bond for stabilization. We observed high levels of neutralization resistance among Envs from 34 bNAb donors, of which 17.6% had elongated V1 regions with extra Cys. We show that extra V1 Cys moderately increase neutralization resistance in an Env from a V2- Apex bNAb-inducer. Modulation of the accessibility of bNAb epitopes on this Env by extra V1 Cys enhanced epitope shielding of several regions, but increased V2 exposure. This suggests that escape from autologous neutralizing activity drove insertion of the extra V1 Cys, creating a modified antigen that may have favored V2 bNAb induction in this donor. Overall, we identify a rare motif of twin Cys in V1 that confers increased neutralization resistance and Env stabilization, is associated with bNAb induction, and may hold potential for incorporation into future HIV bNAb immunogens.

immunology↗

Machine learning strategies to tackle data challenges in mass spectrometry-based proteomics

In computational proteomics, machine learning (ML) has emerged as a vital tool for enhancing data analysis. Despite significant advancements, the diversity of ML model architectures and the complexity of proteomics data present substantial challenges in the effective development and evaluation of these tools. Here, we highlight the necessity for high-quality, comprehensive datasets to train ML models and advocate for the standardization of data to support robust model development. We emphasize the instrumental role of key datasets like ProteomeTools and MassIVE-KB in advancing ML applications in proteomics and discuss the implications of dataset size on model performance, highlighting that larger datasets typically yield more accurate models. To address data scarcity, we explore algorithmic strategies such as self-supervised pretraining and multi-task learning. Ultimately, we hope that this discussion can serve as a call to action for the proteomics community to collaborate on data standardization and collection efforts, which are crucial for the sustainable advancement and refinement of ML methodologies in the field.

bioinformatics↗

The Legionella collagen-like protein employs a unique binding mechanism for the recognition of host glycosaminoglycans

Bacterial adhesion is a fundamental process which enables colonisation of niche environments and is key for infection. However, in Legionella pneumophila, the causative agent of Legionnaires disease, these processes are not well understood. The Legionella collagen-like protein (Lcl) is an extracellular peripheral membrane protein that recognises sulphated glycosaminoglycans (GAGs) on the surface of eukaryotic cells, but also stimulates bacterial aggregation in response to divalent cations. Here we report the crystal structure of the Lcl C-terminal domain (Lcl-CTD) and present a model for intact Lcl. Our data reveal that Lcl-CTD forms an unusual dynamic trimer arrangement with a positively charged external surface and a negatively charged solvent exposed internal cavity. Through Molecular Dynamics (MD) simulations, we show how the GAG chondroitin-4-sulphate associates with the Lcl-CTD surface via unique binding modes. Our findings show that Lcl homologs are present across both the Pseudomonadota and Fibrobacterota-Chlorobiota-Bacteroidota phyla and suggest that Lcl may represent a versatile carbohydrate binding mechanism.

microbiology↗

Fragment ion intensity prediction improves the identification rate of non-tryptic peptides in TimsTOF

Immunopeptidomics plays a crucial role in identifying targets for immunotherapy and vaccine development. Because the generation of immunopeptides from their parent proteins does not adhere to clear-cut rules, rather than being able to use known digestion patterns, every possible protein subsequence within human leukocyte antigen (HLA) class-specific length restrictions needs to be considered during sequence database searching. This leads to an inflation of the search space and results in lower spectrum annotation rates. Peptide-spectrum match (PSM) rescoring is a powerful enhancement of standard searching that boosts the spectrum annotation performance. Low abundant peptides often occur in the field of immunopeptidomics, which is why the highly sensitive timsTOF instruments are increasingly gaining popularity. To improve PSM rescoring for immunopeptides measured using timsTOF instruments, we trained a deep learning-based fragment ion intensity prediction model. 302,105 unique synthesized non-tryptic peptides from the ProteomeTools project were analyzed on a timsTOF-Pro to generate a ground-truth dataset, containing 93,227 MS/MS spectra of 74,847 unique peptides, that was used to fine-tune an existing Prosit model. By applying our fragment ion intensity prediction model, we demonstrate up to 3-fold improvement in the identification of immunopeptides. Furthermore, our approach increased detection of immunopeptides even from low input samples.

bioinformatics↗

The organisation and turnover of synaptic proteins within molecular supercomplexes.

The concept that dimeric protein complexes in synapses can sequentially replace their subunits has been a cornerstone of Francis Cricks 1984 hypothesis, explaining how long-term memories could be maintained in the face of short protein lifetimes. However, it is unknown whether the subunits of protein complexes that mediate memory are sequentially replaced in the brain and if this process is linked to protein lifetime. We address these issues by focusing on supercomplexes assembled by the abundant postsynaptic scaffolding protein PSD95, which plays a crucial role in memory. We used single-molecule detection, super-resolution microscopy and MINFLUX to probe the molecular composition of PSD95 supercomplexes in mice carrying genetically encoded HaloTags, eGFP and mEos2. We found a population of PSD95-containing supercomplexes comprised of two copies of PSD95, with a dominant 12.7 nm separation. Time-stamping of PSD95 subunits in vivo revealed that each PSD95 subunit was sequentially replaced over days and weeks. Comparison of brain regions showed subunit replacement was slowest in the cortex, where PSD95 protein lifetime is longest. Our findings reveal that protein supercomplexes within the postsynaptic density can be maintained by gradual replacement of individual subunits providing a mechanism for stable maintenance of their organization. Moreover, we extend Cricks model by suggesting that synapses with slow subunit replacement of protein supercomplexes and long protein lifetimes are specialized for long-term memory storage and that these synapses are highly enriched in superficial layers of the cortex where long-term memories are stored.

neuroscience↗

Structure and Neutralization Mechanism of a Human Antibody Targeting a Complex Epitope on Zika Virus

We currently have an incomplete understanding of why only a fraction of human antibodies that bind to flaviviruses block infection of cells. Here we define the footprint of a strongly neutralizing human monoclonal antibody (mAb G9E) with Zika virus (ZIKV) by both X-ray crystallography and cryo-electron microscopy. Flavivirus envelope (E) glycoproteins are present as homodimers on the virion surface, and G9E bound to a quaternary structure epitope spanning both E protomers forming a homodimer. As G9E mainly neutralized ZIKV by blocking a step after viral attachment to cells, we tested if the neutralization mechanism of G9E was dependent on the mAb cross-linking E molecules and blocking low-pH triggered conformational changes required for viral membrane fusion. We introduced targeted mutations to the G9E paratope to create recombinant antibodies that bound to the ZIKV envelope without cross-linking E protomers. The G9E paratope mutants that bound to a restricted epitope on one protomer poorly neutralized ZIKV compared to the wild-type mAb, demonstrating that the neutralization mechanism depended on the ability of G9E to cross-link E proteins. In cell-free low pH triggered viral fusion assay, both wild-type G9E, and epitope restricted paratope mutant G9E bound to ZIKV but only the wild-type G9E blocked fusion. We propose that, beyond antibody binding strength, the ability of human antibodies to cross-link E-proteins is a critical determinant of flavivirus neutralization potency.

microbiology↗