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Martinez, O.

Publications and source records attributed to Martinez, O..

9 recordsLinked to original sources

AutoScreen: AI Co-Scientist System for Target Discovery in Functional Genomics

Target discovery in functional genomics remains largely manual and time-consuming, lacking systematic tools for efficient and reproducible gene-level hypothesis generation. We introduce AutoScreen, an AI co-scientist system supporting target discovery through both Pre-screen Design, which constructs perturbation libraries de novo from free-text research descriptions, and Post-screen Analysis, which re-ranks experimental screen hits by integrating statistical scores with biological context. AutoScreen leverages the complementary strengths of multiple specialist agents that perform deep research into multi-modal evidence, information restructuring, parallel searches across >26 biomedical databases, evidence synthesis, and target review to provide transparent, explainable gene prioritization with pipeline provenance. Across 320 genome-scale CRISPR screens as expert-curated benchmarks, AutoScreen achieved a ~19% increase in validated-hit recovery among its top 100 predictions, relative to the strongest agent baseline, and required a 1.2-fold smaller library to recover the same number of hits at the top-500 reference point. AutoScreen reached mean average precision more than two orders-of-magnitude above random baseline. Further, we validated AutoScreen in cancer immune-evasion case studies focusing on natural killer (NK) and T-cell therapeutics. AutoScreen recovered NK-resistance genes that were initially lower-ranked in a leukemia screen, moving MUC1, PDPN, and LRRC15 from raw ranks of 118, 81, 1384 to 5, 44, 659, respectively. In follow-up tumor killing assay with primary human NK cells, individual perturbation validated all three hits successfully. Next, in prospective benchmarking across two cytotoxic T-cell-killing screens, AutoScreen recovered 77.1% of ground-truth hits called by the consensus of two gold-standard analysis pipelines (FDR<0.1), achieving 8% improvement over the strongest general-purpose LLM agent baseline. Finally, we re-analyzed >500 public datasets to construct the AutoScreen Resource Hub, a growing knowledge base of pre-computed, annotated reports for CRISPR screens, RNA-seq differential expression, and gene-level UK Biobank genome-wide association studies. This agentic AI approach enables real-time genomics benchmark construction that are continuously updated, expanded, for evaluating frontier AI co-scientists. Overall, AutoScreen enables AI-powered target discovery to be more auditable, scalable, extensible, and reproducible.

bioengineering↗

Blood-brain barrier model architecture shapes peripheral immune cell trafficking in Parkinson's disease

Parkinsons disease (PD) is a neurodegenerative disorder traditionally characterized by dopaminergic neuron loss in the substantial nigra pars compacta, but peripheral immune dysregulation and blood-brain barrier (BBB) dysfunction have been increasingly implicated in disease etiology. However, how circulating immune cells interact with the human BBB and how these interactions are captured across experimental models remains poorly understood. In particular, human BBB models offer multiple platforms to interrogate these biological questions, with organ-on-chip approaches attracting significant interest. In this context, it is essential to determine whether model architecture influences the assessment of immune-endothelial interactions in PD, and if it may lead to fundamentally different interpretations of immune cell trafficking at the human BBB. Here, we compared peripheral blood mononuclear cells (PBMCs) from control donors or individuals with PD in human induced pluripotent stem cell (iPSC)-derived BBB models to determine how static and dynamic BBB systems influence immune cell behavior. To do so, we leveraged our brain chip platform to establish a model based on expression of the PD-associated SNCA triplication mutation. Using a two-dimensional transwell system and a three-dimensional (3D) microfluidic BBB chip, we evaluated PBMC attachment and transmigration under conditions of PBMC disease status, endothelial genotype associated with SNCA triplication, and exposure to -synuclein (-Syn) monomers or preformed fibrils (PFFs). PBMCs from PD donors showed increased baseline reactivity and altered endothelial interactions compared with controls. In transwell models, SNCA triplication increased PBMC attachment and selectively enhanced PD PBMC transmigration, while PFF increased attachment without affecting transmigration. In contrast, in the microfluidic BBB chip, attachment was largely unchanged by endothelial genotype or -Syn exposure, whereas transmigration increased following -Syn monomer pre-treatment. Together, PBMC-BBB interactions in PD appear to be shaped by immune cell status, endothelial genotype, and -Syn exposure, but are strongly influenced by BBB model dimensionality and flow. This study underscores the importance of physiologically relevant multicellular and flow-based BBB systems and provides a human-focused framework for studying peripheral immune cell trafficking across the diseased BBB. These findings also emphasize that biological insights into BBB function are inherently shaped by the experimental model used, underscoring the need for complementary human BBB platforms.

neuroscience↗

Genomic dialects: How amino acid properties and the second codon base shape the informational accents of life

Codon Usage Bias (CUB) is a fundamental feature of genomic architecture, reflecting a balance between mutational pressure and natural selection. We propose a "genomic dialects" framework, where species-specific CUB profiles represent "informational accents" constrained by biochemical and structural requirements. Utilizing a normalized informational index based on Shannons entropy, we analyzed CUB profiles for 18 amino acids across 1,406 species from the three domains of life. Linear models were employed to investigate the relationship between CUB and physicochemical properties, including Saiers second-codon-base classification, molecular volume, hydrophobicity, aliphatic/aromatic status, and dissociation constants. CUB distributions are highly skewed, with > 52% of values below 0.1, suggesting a near-optimal use of the genetic codes potential. We demonstrate that amino acid properties significantly influence CUB, with Saiers classification explaining up to 69% of variance in Archaea and{approx} 47% across all taxa. Hydrophobic amino acids (Q1 class) consistently exhibit higher average CUB than hydrophilic ones, particularly in microbes. Individual species models reveal extreme correlations; for example, in the alga Chlamydomonas reinhardtii, Saier classes explain > 95% of CUB variance. Finally, we show that CUB-based dendrograms represent phenetic similarity ("genomic accents") rather than reliable phylogenetic reconstructions, as they rarely coincide with the true Tree of Life. Our findings indicate that the "rules" of genomic dialects are largely anchored in the dual requirements of translational fidelity and protein stability. The observed "informational accents" are proximately governed by the metabolic and genomic machinery under the constraints of the drift-barrier hypothesis. This study provides a robust framework for understanding how the physical realities of amino acids have shaped the evolution of the genetic codes informational use across the tree of life.

bioinformatics↗

Parkinson's disease risk factors are expressed at brain barriers.

Parkinsons disease (PD) is characterized by the selective loss of dopaminergic neurons in the substantia nigra pars compacta, but whether its etiology is cell autonomous remains unclear. Increasing evidence implicates the blood-central nervous system (CNS) barriers in disease development, highlighting the importance of identifying genetic risk factors linked to cells forming the cerebrovasculature to advance this emerging area of research. The objective of this study is to identify PD genetic risk factors associated with blood-brain (BBB) and blood-cerebrospinal fluid (BCSFB) barriers, and to validate protein localization in human tissue and experimental models. To do so, we integrated genome-wide association studies and single nuclei RNA-sequencing datasets from the human postmortem substantia nigra (SN), midbrain, or cortical samples from control and PD donors. An in-depth bioinformatics analysis identified genes enriched in cell types that form the multicellular architecture of brain barriers, including CAVIN2, ANXA1, ANO2, and LRP1B. We further validated whether corresponding proteins were present in cell types associated with the blood-CNS barriers in human and mouse post-mortem tissues, as well as in iPSC-differentiated cells and choroid plexus organoids. Results showed that quantifying the proportion of endothelial cells expressing PD-related genes was under-evaluated at the transcript level compared to immunofluorescence analyses. In addition, we observed that CAVIN2 and ANXA1 proteins were more abundant at the vasculature of the substantia nigra vs. cortex, and CAVIN2 protein levels were reduced in PD vs. control human postmortem tissues. In contrast, the investigation of mouse postmortem samples demonstrated that the CAVIN2 protein is only present in a subset of mouse blood vessels, compared to nearly all vessels in human tissue. Similarly, mouse ANXA1 protein localizes to dopaminergic neurons of the substantia nigra and not at the vasculature, as seen in human tissue. The primary outcome of this study is the identification of PD-relevant risk genes specifically expressed at brain barriers and enriched in PD-relevant brain regions. The secondary outcome is the demonstration of poor transcript-protein correlation in - at least - a subset of PD risk factors, and a low interspecies conservation of protein localization for the selected candidates. In conclusion, the BBB and BCSFB may represent understudied contributors to PD, endothelial-specific proteins appear differentially regulated compared to transcripts, and experimental models require comprehensive validation to ensure relevance to the human condition.

neuroscience↗

GLUT5 armouring enhances adoptive T cell therapy anti-tumour activity under glucose-limiting conditions

Cancer immunotherapy with engineered T cells has become a standard treatment for certain hematologic cancers. However, clinical trial outcomes for solid tumours are significantly lagging. A primary challenge in solid tumours is the lack of essential metabolites in the tumour microenvironment, such as glucose, due to poor vascularization and competition with tumour cells. To address this, we modified T cells to use fructose as an alternative energy source by introducing ectopic GLUT5 expression. We show that "GLUT5-armored" T cells, engineered with either chimeric antigen receptors (CARs) or an ectopic T cell receptor (TCR), achieve enhanced anti-tumour activity in low-glucose environments in both in vitro and in vivo models. This straightforward modification is compatible with current clinical approaches and may improve the efficacy of T cell therapies for solid tumours. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/633365v1_ufig1.gif" ALT="Figure 1"> View larger version (62K): org.highwire.dtl.DTLVardef@15e10e0org.highwire.dtl.DTLVardef@a5f029org.highwire.dtl.DTLVardef@3a32daorg.highwire.dtl.DTLVardef@e09ff9_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

LC-MS/MS characterization of SOBERANA(R)02, a receptor binding domain-tetanus toxoid conjugate vaccine against SARS-CoV-2

SOBERANA(R)02 is a safe and effective conjugate vaccine against SARS-CoV-2, produced using the maleimide-thiol chemistry. In this vaccine, the Cys538 in the recombinant receptor binding domain (RBD) of SARS-CoV-2 is linked, through a thiosuccinimide linker, to lysine residues of tetanus toxoid (TT) preparation. LC-MS/MS analysis revealed that TT is a complex mixture of proteins, similar to other TTs where the detoxified tetanus neurotoxin (d-TeNT) has been shown to be the most abundant protein (30-56%), regardless the quantification method used. The fifteen most abundant proteins account for approximately 78% of the total proteins. LC-MS/MS analysis of the activation process showed that 102 out of 107 lysine residues in the d-TeNT incorporated a maleimide group. In contrast, when tryptic peptides isolated by Ni2+-NTA affinity chromatography, were analyzed by LC-MS/MS, only 22 Lys residues in the d-TeNT were cross-linked to the RBD C-terminal tryptic peptide (538CVNF541-HHHHHH), probably due to steric hindrance. Twelve and eighteen conjugation sites were assigned based on the identification of linear peptides carrying a conjugated lysine residues ({Delta}m = +1454.58 Da or {Delta}m = +1472.59 Da) and cross-linked peptides with stabilized linker forms, respectively. Eight conjugation sites were coincidently assigned by both strategies. The assignment of the conjugation sites was manually validated by observed regularities (z[&ge;]3+, XIC, immonium ions, specific linker fragment ions) not considered by the identification software (PEAKS, Kojak and pLink2). The RBD was also conjugated, but to a lesser extent, to ten other low abundance carrier proteins. To our knowledge, this work is the first report of conjugation site assignment in a TT-based conjugate vaccine.

biochemistry↗

Atypical DNA methylation, sRNA size distribution and female gametogenesis correlate with genome compaction in Utricularia gibba

O_LIThe most studied DNA methylation pathway in plants is the RNA Directed DNA Methylation (RdDM), which is a conserved mechanism that involves noncoding-RNAs to control the expansion of intergenic regions. However, little is known about relationship between plant genome size reductions and DNA methylation. C_LIO_LIBecause the compact genome size of the carnivorous plant Utricularia gibba, we investigate in this plant the noncoding-RNA landscape and DNA methylation through a combination of cytological, evolutionary, and genome-wide transcriptomic and methylation approaches. C_LIO_LIWe report an unusual distribution of noncoding RNAs in U. gibba in comparison with other characterized angiosperms, which correlated with a lower level of global genome methylation, as determined by a novel strategy based on long-read DNA sequencing and corroborated by whole-genome bisulfite analysis. Moreover, found that genes involved in the RdDM pathway may not be functionally active in U. gibba, including a truncated DICER-LIKE 3 (DCL3), involved in the production of 24-nt small-RNAs. C_LIO_LIOur findings suggest that selective pressure to conserve a fully functional RdDM pathway might be reduced in compact genomes and a defective DCL3 correlate with a decreased proportion of 24-nt small-RNAs and developmental alterations in U. gibba, which could represent an initial step in the evolution of apomixis. C_LI

plant biology↗

Transcriptomic Analyses Throughout Chili Pepper Fruit Development Reveal Novel Insights into Domestication Process

Chili pepper (Capsicum spp.) is both an important crop and a model for domestication studies. Here we performed a time course experiment to estimate standardized gene expression profiles across fruit development for six domesticated and four wild chili pepper ancestors. We sampled the transcriptome every 10 days, from flower to fruit at 60 Days After Anthesis (DAA), and found that the mean standardized expression profile for domesticated and wild accessions significantly differed. The mean standardized expression was higher and peaked earlier for domesticated vs. wild genotypes, particularly for genes involved in the cell cycle that ultimately control fruit size. We postulate that these gene expression changes are driven by selection pressures during domestication and show a robust network of cell cycle genes with a time-shift in expression which explains some of the differences between domesticated and wild phenotypes.

evolutionary biology↗

On an algorithmic definition for the components of the minimal cell

Living cells are highly complex systems comprising a multitude of elements that are engaged in the many convoluted processes observed during the cell cycle. However, not all elements and processes are essential for cell survival and reproduction under steady-state environmental conditions. To distinguish between essential from expendable cell components and thus define the minimal cell and the corresponding minimal genome, we postulate that the synthesis of all cell elements can be represented as a finite set of binary operators, and within this framework we show that cell elements that depend on their previous existence to be synthesized are those that are essential for cell survival. An algorithm to distinguish essential cell elements is presented and demonstrated within an interactome. Data and functions implementing the algorithm are given as supporting information. We expect that this algorithmic approach will lead to the determination of the complete interactome of the minimal cell, which could then be experimentally validated. The assumptions behind this hypothesis as well as its consequences for experimental and theoretical biology are discussed.

bioinformatics↗