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Jimenez, D.

Publications and source records attributed to Jimenez, D..

15 recordsLinked to original sources

MicrobeRT: A Framework and Suite of Fine-tuned Language Models for Genomic Sequences

Accurate and reproducible metagenomic analysis is essential for effective infectious disease surveillance. Targeted diagnostics such as culturing, antigen assays, and multiplex PCR panels identify only predefined organisms and can fail to identify atypical or novel infections. Shotgun metagenomics offers hypothesis-free detection, but adoption is limited by workflow complexity, dependence on mutable reference databases, and high computational cost. To combat these challenges, we introduce MicrobeRT, an integrated suite of genomic language models fine-tuned to classify metagenomic sequencing reads across three tasks: (i) species level taxonomic identification, (ii) antibiotic resistance gene detection, and (iii) pathogenicity assessment. The framework builds on three pre-trained genomic language models - Nucleotide Transformer (Dalla-Torre et al 2025), DNABERT (Ji et al 2021, Zhou et al 2024), and HyenaDNA (Nguyen et al 2024) - leveraging their large-scale genomic pre-training, adaptability to downstream tasks, and, in the case of HyenaDNA, ability to capture long-range sequence dependencies. The models are fine-tuned on large, curated datasets spanning microbial, viral, fungal, and human genomes, including more than 500,000 genomes and 250,000 antibiotic resistance gene sequences. To evaluate the performance of our fine-tuned genomic language models across classification tasks, we developed a benchmarking framework that compares MicrobeRT against state-of-the-art (SOTA) bioinformatics tools. Across both simulated and empirical datasets, the models achieve strong performance while reducing computational overhead. MicrobeRT is released as open-source software, enabling further fine-tuning and reproducible integration of alternative models and classifiers. We also demonstrate seamless, drop-in integration by incorporating our fine-tuned taxonomic classification models as an optional add-on within the open-source TaxTriage pipeline (Merritt et al 2026). MicrobeRT demonstrates the feasibility of three clinically relevant multi-label analyses, offering a practical path to scalable, reproducible metagenomic diagnostics and enabling broader deployment of AI/ML-enhanced infectious disease testing.

bioinformatics↗

Pocket-Conditioned Generation and Down-Selection of Non-Oxime Reactivators

Acetylcholinesterase reactivation is a structure-constrained design problem in which chemical plausibility, access to central nervous system, pocket compatibility, and reactivation geometry must be considered together. We report a computational workflow for generating and down-selecting candidate non-oxime reactivators in the paraoxon-inhibited human acetylcholinesterase pocket. For generating the candidates, the first-round utilitezed pocket-conditioned DrugFlow, but due to solubility issues, the second-round candidates were output form FlexFlow, DrugFlow-OOD, DrugFlow preference alignment, and pocket-specified BoltzMol-1. A property-guided DrugDiff output provided a protein-unconditioned baseline. Although 93.9% of the DrugDiff subset passed Lipinski criteria for druglikeness, its median synthetic accessibility (SA) score signalled that it was difficult to synthesize compared against other generative approaches. A strict predicted blood-brain barrier and solubility gate retained 31.0% of Base DrugFlow, 61.0% of FlexFlow, 27.5% of DrugFlow-OOD, 3.8% of DrugFlow-PA, and 35.1% of BoltzMol-1. The second-round top-ten lists had lower SA scores and higher quantitative estimate of drug-likeness (QED) values than the DrugDiff shortlist, while DrugDiff had fewer aggregate heuristic violations. This work compares the best performing generative drug discovery models with suggested down sleection approaches for human acetylcholinesterase reactivation.

bioengineering↗

Female-Biased IL-17/STAT3 Signaling Marks Dementia-Associated Microglial Inflammation in Alzheimer's Disease

INTRODUCTION: Alzheimer's disease (AD) disproportionately affects women, but the underlying mechanisms are not fully understood. We compare sex-specific molecular changes across AD with and without dementia at single-cell resolution. METHODS: We performed sex-stratified single-nucleus transcriptomic analysis of human AD to dissect sex-specific differences in dementia progression, using the SEA-AD cohort for discovery and the ROSMAP and NBB datasets, together with 5xFAD mouse models, for validation. Donors were classified as no-dementia controls, no-dementia AD, or dementia AD, followed by donor-level pathway analysis, de novo microglial clustering, communication modeling, and cytokine-response enrichment RESULTS: Females with AD dementia showed enhanced inflammatory pathway activity across glial, neuronal and vascular-associated cell types, with the strongest enrichment in microglia. This female-biased program centered on IL6-JAK-STAT3 signaling and increased STAT3 expression in microglia and astrocytes. These results were validated in the ROSMAP and NBB datasets and conserved in the 5xFAD mouse model. Microglial clustering resolved 18 states and revealed sex-divergent disease remodeling, including female-specific expansion of redox-reactive and CD163+ macrophage-primed states. Cell:cell communication analysis identified female-biased TGF{beta}/GRN signaling, male-biased CD99 signaling, and dementia-associated SPP1-integrin communication with the vasculature. Microglial cytokine-response analysis identified IL-2 response as a dementia-associated signature in both sexes, alongside a female-biased IL-17/interferon response and a male-biased IL-7 response. DISCUSSION: These findings identify a disease-emergent, female-biased STAT3-centered neuroinflammatory program in human and mouse AD, linking sex-specific microglial remodeling to cytokine responsiveness and glial-vascular communication. The results suggest that sex-specific changes in neuroinflammation pathways in microglia and other cell types are associated with progression to dementia.

neuroscience↗

Microbiological Survey of the San Pedro Basin Subseafloor

Marine subseafloor sediments host extensive microbial communities that drive global biogeochemical processes. Despite its proximity to one of the most densely populated and economically important coastal regions in the world, the sub benthic ecology of the San Pedro Channel, the waterway separating Los Angeles County from Santa Catalina Island, remains largely uncharacterized. To establish the foundational knowledge required for future impact assessment studies, we initiated a sediment coring survey that generated a water and sediment depth standardized transect across the sloping flanks of the San Pedro Basin. Here, we describe the early development of an integrated subseafloor microbiological catalogue for this region of intense maritime activity incorporating molecular ecology, microbial isolation and cultivation, and physiological assays. This initial effort is designed not as a direct comparison between basin flanks, but as a baseline assessment that captures ecological and microbiological variation across paired sides matched in water column depth and sediment depth beneath seafloor. Accordingly, we provide a cross channel coordinated dataset of subseafloor microbial communities and cultivated representatives from San Pedro Basin sediment, offering a critical starting point for understanding natural variability and for detecting potential signatures of environmental or anthropogenic disturbance. Ultimately, this baseline will support long{square}term monitoring efforts and supply a curated collection of isolates for future experimental microbiology and comparative genomics research.

ecology↗

Impaired Associative Memory, Inference, and Theta Dynamics in Postictal Psychosis of Epilepsy

Postictal psychosis (PIP) is a severe complication occurring in 2% of people with epilepsy (PWE) whose underlying pathophysiology remains poorly understood. Although historically considered separate from other forms of psychosis, newer evidence demonstrates a shared genetic susceptibility. People with schizophrenia are typically impaired at both associative learning and inferring connections between overlapping associations. Successful associative encoding, retrieval, and inference can each be predicted by changes in frontotemporal theta band activity, which is impaired in rodent models and people with schizophrenia. Here, we recorded high-density scalp EEG from PWE with history of PIP and well-matched control participants while they undertook a memory inference task. We found that associative memory and inference were both impaired in the PIP group, despite no difference in item recognition. Moreover, we found disrupted theta activity during memory encoding and the retrieval of inferred associations in PWE with PIP that likely originated from the medial temporal and frontal lobes. These results suggest a pattern of behavioural deficits and altered neural dynamics common to both PIP and schizophrenia. Interpreted in conjunction with previous genetic studies, they may reflect shared neural mechanisms contributing to psychopathology in both conditions and argue that PIP is a model of more general psychoses.

neuroscience↗

Global biogeography of mangrove sediment microbiomes is structured by a conserved core and environmental selection

Mangrove sediments are globally important biogeochemical hotspots, yet the large-scale organization and assembly of their microbiomes remain poorly resolved. Here, we compiled and analysed 390 shotgun metagenomes from mangrove sediments across 43 sites worldwide to quantify how diversity, spatial turnover, and ecological processes structure microbial communities across environmental and geographic gradients. We identify a striking dual architecture in mangrove sediment microbiomes. A remarkably small and ubiquitous taxonomic core, representing a minor fraction of total richness but dominating community abundance, persists across continents, climatic regimes, and marine realms. This core is composed primarily of anaerobic microbial lineages associated with carbon, nitrogen, and sulfur cycling and shows limited spatial and environmental turnover. In contrast, the non-core fraction is highly diverse, responds strongly to climatic and edaphic gradients, and drives most biogeographic differentiation. Assembly-process modelling reveals that deterministic selection dominates global taxonomic turnover, with homogeneous selection stabilizing shared community components and heterogeneous selection promoting regional differentiation, while dispersal limitation plays a secondary role. Network analyses further show that core taxa occupy structurally central positions in microbial co-occurrence networks, supporting overall connectivity despite pronounced regional variation in peripheral community composition. Together, these results demonstrate that mangrove sediment microbiomes combine a conserved functional backbone with an environmentally responsive periphery. This organization reconciles global functional continuity with strong regional differentiation and provides a basis for anticipating microbiome responses to environmental change in mangrove ecosystems.

ecology↗

Evaluating the Effectiveness of Parameter-Efficient Fine-Tuning in Genomic Classification Tasks

Foundation models are increasingly being leveraged for biological tasks. To address the high memory requirements of fine-tuning large pre-trained language models, parameter efficient fine-tuning (PEFT) methods are also being increasingly utilized. Previous studies have shown minimal, if any, loss in performance when using PEFT on binary classification tasks. However, the impact of using PEFT on tasks with large classification spaces has not been systemically evaluated. In this work, we apply PEFT to the problem of taxonomic classification using pre-trained genomic language models as the classification backbone. We explore various training strategies--including PEFT, full fine-tuning, and partial fine-tuning--for classifying sequences at the superkingdom, phylum, and genus levels. We find that PEFT-trained models significantly underperform compared to those trained via full fine-tuning or partial fine-tuning. Additionally, we demonstrate increased performance of pretrained models over those randomly initialized.

bioinformatics↗

A breast tissue-specific epigenetic clock provides accurate chronological age predictions and reveals de-correlation of age and DNA methylation in tumor-adjacent and tumor samples

Epigenetic clocks have been widely used to estimate biological age across various tissues, but their accuracy in breast tissue remains suboptimal. Pan-tissue models such as Horvaths and Hannums clocks, perform poorly in predicting chronological age in breast tissue, underscoring the need for a tissue-specific approach. In this study, we introduce a Breast Tissue-specific Epigenetic Clock (BTEC), developed using DNA methylation data from 553 healthy breast tissue samples across seven different studies. BTEC significantly outperformed pan-tissue clocks, demonstrating superior correlation with chronological age (r=0.88) and lower prediction errors (MAE=3.27 years) without requiring for dataset-specific regressions adjustments. BTECs chronological age predictions for tumor-adjacent samples showed distortions, with an average deviation of -1.76 years, which was even more pronounced in tumor samples, where the average difference between predicted and chronological age was -12.29 years. When analyzed by molecular subtype, the distortion was greater in the more aggressive HER2+ and TNBC tumors compared to HR+ tumors. The probes used by BTEC were associated with known oncogenes, genes involved in estrogen metabolism, cadherin binding and fibroblast growth factor binding. Despite the general rejuvenation observed in tumor tissue compared to normal breast, the correlation between BTECs predictions and cancer-related survival indicated that TNBC tumors with increased epigenetic ages had significant lower survival.

cancer biology↗

Glutaminolysis promotes the function of follicular helper T cells in lupus-prone mice

Glutamine metabolism is essential for T cell activation and functions. The inhibition of glutaminolysis impairs Th17 cell differentiation and alters Th1 cell functions. There is evidence for an active glutaminolysis in the immune cells of lupus patients. Treatment of lupus-prone mice with glutaminolysis inhibitors ameliorated disease in association with a reduced frequency of Th17 cells. This study was performed to determine the role of glutaminolysis in murine Tfh cells, a critical subset of helper CD4+ T cells in lupus that provide help to autoreactive B cells to produce autoantibodies. We showed that lupus Tfh present a high level of glutamine metabolism. The pharmacological inhibition of glutaminolysis with DON had little effect on the Tfh cells of healthy mice, but it reduced the expression of the critical costimulatory molecule ICOS on lupus Tfh cells, in association with a reduction of autoantibody production, germinal center B cell dynamics, as well as a reduction of the frequency of atypical age-related B cells and plasma cells. Accordingly, profound transcriptomic and metabolic changes, including an inhibition of glycolysis, were induced in lupus Tfh cells by DON, while healthy Tfh cells showed little changes. The T cell-specific inhibition of glutaminolysis by deletion of the gene encoding for the glutaminase enzyme GLS1 largely phenocopied the effects of DON on Tfh cells and B cells in an autoimmune genetic background with little effect in a congenic control background. These results were confirmed in an induced model of lupus. Finally, we showed that T cell-specific Gls1 deletion impaired T- dependent humoral responses in autoimmune mice as well as their Tfh response to a viral infection. Overall, these results demonstrated a greater intrinsic requirement of lupus Tfh cells for their helper functions, and they suggest that targeting glutaminolysis may be beneficial to treat lupus.

immunology↗

The transcriptional landscape of metastatic hormone-naive prostate cancer

Metastatic hormone-naive prostate cancer (mHNPC) is an infrequent form of this tumour type that is characterized by metastasis at the time of diagnosis and accounts for 50% of prostate cancer-related deaths. Despite the extensive characterization of localized and metastatic castration resistant prostate cancer (mCRPC), the molecular characteristics of mHNPC remain largely unexplored. Here we provide the first extensive transcriptomics characterization of mHNPC. We generated discovery and validation bulk and single-cell RNA-Seq datasets and performed integrative computational analysis in combination with experimental studies. Our results provide unprecedented evidence of the distinctive transcriptional profile of mHNPC and identify stroma remodelling as a predominant feature of these tumours. Importantly, we discover a central role for the transcription factor SOX11 in triggering a heterotypic communication that is associated to the acquisition of metastatic properties. Our study will constitute an invaluable resource for a profound understanding of mHNPC that can influence patient management.

cancer biology↗

Maternal Alcohol Drinking Patterns Predict Offspring Neurobehavioral Outcomes

SIGNIFICANCEThe timing, rate, and quantity of gestational alcohol consumption, collectively referred to here as Maternal Drinking Patterns (MDPs), are of known importance to fetal developmental outcomes. Though studies in rodents exist that have investigated the impact of gestational alcohol drinking characteristics, few have sought to determine the impact of MDPs on offspring behavioral outcomes. METHODSWe first used specialized equipment to record the precise amount and timing of binge alcohol consumption in pregnant mouse dams, and then characterized MDPs using Principle Component Analysis (PCA). We focused these analyses on the first fifteen minutes of every gestational drinking session when dams consumed the majority of each sessions alcohol (a phenomenon known as front-loading), as well as the entire 2 hour session across all days of gestation. We next tested offspring in open field and rotarod assays and evaluated these behavioral results in the context of MDPs. RESULTSMale alcohol exposed mice exhibited longer latencies to fall on the rotarod compared to their controls, which we attribute to a delayed decrease in body weight-gain not observed in females. This effect was found to be associated with MDPs within the first fifteen minutes of drinking, but not other MDPs. Female alcohol exposed mice had significantly reduced total locomotor activity in the open field compared to controls, and this effect was also associated with MDPs but only of the entire drinking session. Surprisingly, total gestational alcohol consumption alone was not associated with any particular behavioral outcome. Furthermore, we replicated robust behavioral data demonstrating development of allodynia in alcohol exposed mice where it did not develop in controls. CONCLUSIONSTo our knowledge, this report represents the highest resolution assessment of alcohol drinking throughout gestation, and one of few to have identified relationships between specific alcohol MDPs and neurobehavioral outcomes in offspring. Specifically, based on characteristics of the PCA groups, we found evidence that the rate of alcohol front-loading leads to developmental delays in males, whereas an interaction of front-loading rate and duration, overall persistence, and total amount consumed lead to a female-only decrease in locomotor activity. Beyond these results, we provide a method for precise and accessible tracking of such data.

neuroscience↗

Mechanical force of uterine occupation enables large vesicle extrusion from proteostressed maternal neurons

Large vesicle extrusion from neurons may contribute to spreading pathogenic protein aggregates and promoting inflammatory responses, two mechanisms leading to neurodegenerative disease. Factors that regulate extrusion of large vesicles, such as exophers produced by proteostressed C. elegans touch neurons, are poorly understood. Here we document that mechanical force can significantly potentiate exopher extrusion from proteostressed neurons. Exopher production from the C. elegans ALMR neuron peaks at adult day 2 or 3, coinciding with the C. elegans reproductive peak. Genetic disruption of C. elegans germline, sperm, oocytes, or egg/early embryo production can strongly suppress exopher extrusion from the ALMR neurons during the peak period. Conversely, restoring egg production at the late reproductive phase through mating with males or inducing egg retention via genetic interventions that block egg-laying can strongly increase ALMR exopher production. Overall, genetic interventions that promote ALMR exopher production are associated with expanded uterus lengths and genetic interventions that suppress ALMR exopher production are associated with shorter uterus lengths. In addition to the impact of fertilized eggs, ALMR exopher production can be enhanced by filling the uterus with oocytes, dead eggs, or even fluid, supporting that distention consequences, rather than the presence of fertilized eggs, constitute the exopher-inducing stimulus. We conclude that the mechanical force of uterine occupation potentiates exopher extrusion from proximal proteostressed maternal neurons. Our observations draw attention to the potential importance of mechanical signaling in extracellular vesicle production and in aggregate spreading mechanisms, making a case for enhanced attention to mechanobiology in neurodegenerative disease.

neuroscience↗

Metabolic snapshot of plasma samples reveals new pathways implicated in SARS-CoV-2 pathogenesis

Despite of the scientific and human efforts to understand COVID-19, there are questions still unanswered. Variations in the metabolic reaction to SARS-CoV-2 infection could explain the striking differences in the susceptibility to infection and the risk of severe disease. Here, we used untargeted metabolomics to examine novel metabolic pathways related to SARS-CoV-2 susceptibility and COVID-19 clinical severity using capillary electrophoresis coupled to a time-of-flight mass spectrometer (CE-TOF-MS) in plasma samples. We included 27 patients with confirmed COVID-19 early after symptom onset who were prospectively followed and 29 healthcare workers heavily exposed to SARS-CoV-2 but with low susceptibility to infection ( nonsusceptible). We found that the metabolite profile was predictive of the study group. We identified a total of 55 metabolites as biomarkers of SARS-CoV-2 susceptibility or COVID-19 clinical severity. We report the discovery of new plasma biomarkers for COVID-19 that provide mechanistic explanations for the clinical consequences of SARS-CoV-2, including mitochondrial and liver dysfunction as a consequence of hypoxemia (citrulline, citrate, and BAIBA), energy production and amino acid catabolism (L-glycine, L-alanine, L-serine, L-proline, L-aspartic acid and L-histidine), endothelial dysfunction and thrombosis (citrulline, L-ADMA, 2-AB, and Neu5Ac), and we found interconnections between these pathways. In summary, in this first report of the metabolomic profile of individuals with severe COVID-19 and SARS-CoV-2 susceptibility by CE-MS, we define several metabolic pathways implicated in SARS-CoV-2 susceptibility and COVID-19 clinical progression that could be developed as biomarkers of COVID-19.

biochemistry↗

A noncatalytic activity of the H4K20 demethylase DPY-21 regulates condensin DC binding

Condensin is a multi-subunit SMC complex that binds to and compacts chromosomes. Here we addressed the regulation of condensin binding dynamics using C. elegans condensin DC, which represses X chromosomes in hermaphrodites for dosage compensation. We established fluorescence recovery after photobleaching (FRAP) using the SMC4 homolog DPY-27 and showed that a well-characterized ATPase mutation abolishes its binding. Next, we performed FRAP in the background of several chromatin modifier mutants that cause varying degrees of X-chromosome derepression. The greatest effect was in a null mutant of the H4K20me2 demethylase DPY-21, where the mobile fraction of condensin DC reduced from [~]30% to 10%. In contrast, a catalytic mutant of dpy-21 did not regulate condensin DC mobility. Hi-C data in the dpy-21 null mutant showed little change compared to wild type, uncoupling Hi-C measured long-range DNA contacts from transcriptional repression of the X chromosomes. Together, our results indicate that DPY-21 has a non-catalytic role in regulating the dynamics of condensin DC binding, which is important for transcription repression.

cell biology↗

Novel Chlamydiae and Amoebophilus endosymbionts are prevalent in wild isolates of the model social amoebae Dictyostelium discoideum

Amoebae interact with bacteria in diverse and multifaceted ways. Amoeba predation can serve as a selective pressure for the development of bacterial virulence traits. Bacteria may also adapt to life inside amoebae, resulting in symbiotic relationships (pathogenic or mutualistic). Indeed, particular lineages of obligate bacterial endosymbionts have been found in different amoebae. Here, we screened an extensive collection of Dictyostelium discoideum wild isolates for the presence of such bacterial symbionts using PCR primers that identify these endosymbionts. This is the first report of obligate symbionts in this highly-studied amoeba species. They are surprisingly common, identified in 42% of screened isolates (N=730). Members of the Chlamydiae phylum are particularly prevalent, occurring in 27% of the host strains. They are novel and phylogenetically distinct. We also found Amoebophilus symbionts in 8% of screened isolates (N=730). Antibiotic-cured amoebae behave similarly to their endosymbiont-infected counterparts, suggesting that endosymbionts do not significantly impact host fitness, at least in the laboratory. We found several natural isolates were co-infected with multiple endosymbionts, with no obvious fitness effects of co-infection under laboratory conditions. The high prevalence and novelty of amoeba endosymbiont clades in the model organism D. discoideum opens the door to future research on the significance and mechanisms of amoeba-symbiont interactions.

microbiology↗