Biology subjects

Almeida, A.

Publications and source records attributed to Almeida, A..

At least 19 recordsLinked to original sources

bioRxiv2026

SOX11 stimulates γδ T-cell differentiation and synergizes with LMO2 and MYCN to drive γδ-like T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is a heterogeneous hematologic malignancy in which LMO2 {gamma}{delta}-like T-ALL represents a rare but clinically aggressive subtype associated with poor treatment response and inferior survival. Integrated transcriptomic analyses identified high SOX11 expression as a defining feature of high-risk LMO2 {gamma}{delta}-like T-ALL, where elevated SOX11 levels correlated with refractory disease and poor clinical outcome. To investigate the functional role of SOX11 in {gamma}{delta} T-cell biology and leukemogenesis, we generated a conditional R26-SOX11 mouse model enabling lineage-specific SOX11 overexpression in T-cell progenitors. SOX11 expression promoted expansion of the innate {gamma}{delta} T-cell compartment in thymus, spleen, and bone marrow, accompanied by transcriptional activation of {gamma}{delta} T-cell differentiation, activation, and cytotoxicity programs. However, SOX11 overexpression alone was insufficient to induce leukemia or confer thymocyte self-renewal capacity. In contrast, combined SOX11 and LMO2 overexpression markedly accelerated T-ALL development and strongly increased the incidence of {gamma}{delta}-like leukemias, thereby recapitulating the human high-risk LMO2 {gamma}{delta}-like T-ALL subtype. Mechanistically, SOX11 expanded the pre-leukemic DN3 thymocyte compartment in LMO2-driven mouse model while promoting differentiation toward the {gamma}{delta} lineage. Transcriptomic profiling identified activation of MYCN-associated transcriptional programs in SOX11/LMO2 pre-leukemic thymocytes. Consistently, MYCN was highly expressed in human LMO2 {gamma}{delta}-like T-ALL, and recurrent stabilizing MYCN P44L mutations were enriched in this subtype. Functional validation using genetic and transplantation-based mouse models demonstrated that SOX11 cooperates with MYCN to accelerate T-ALL onset. Together, these findings establish a cooperative SOX11-MYCN oncogenic axis driving {gamma}{delta}-like T-ALL and provide a novel preclinical model for investigating therapeutic vulnerabilities in this high-risk leukemia subtype.

cancer biology↗

bioRxiv2026

Mitochondrial pyruvate import in astrocytes links anaplerosis to seizure resistance

Astrocytes are glycolytic cells that convert a substantial fraction of glucose-derived pyruvate into lactate, a metabolite implicated in supporting neuronal energy demand and modulating excitability, plasticity and memory. This view has placed astrocytic lactate production and export at the centre of astrocyte-neuron metabolic coupling, but whether mitochondrial pyruvate utilization in astrocytes is dispensable in vivo or fulfils an essential function in the intact brain remains unknown. Here we show that adult astrocyte-specific deletion of Mpc2, encoding an obligatory mitochondrial pyruvate carrier subunit, causes motor deficits, neuronal hyperexcitability and seizure-associated lethality. Metabolic profiling revealed pyruvate diversion toward alanine as an unsuccessful compensatory bypass, together with impaired tricarboxylic acid-cycle metabolism and an imbalance in neurotransmitter-related pools, including glutamate, glutamine and {gamma}-aminobutyric acid. Thus, astrocytic mitochondrial pyruvate import is not primarily required for bioenergetic purposes but acts as a non-redundant anaplerotic gate that maintains neurotransmitter homeostasis, excitation-inhibition balance and seizure resistance in vivo.

neuroscience↗

bioRxiv2026

Neuroprotection following FLASH-RT may be mediated by sustained glutamate receptor AMPAR activation in CA3 neurons

To elucidate the early mechanisms underlying the long-term neuroprotective effect of FLASH-RT in the normal brain, spatial transcriptomics (Nanostring) were performed after whole-brain irradiation of C57BL/6J mice with either 1 or 3 fractions of 10 Gy at 5.6x106 Gy/s (1 pulse-FLASH) or at conventional dose-rate 0.1 Gy/s. FLASH -RT induced a distinct transcriptomic signature in the CA3 and DG neurons, with upregulation of genes encoding glutamate receptors, involved in calcium signaling, long-term potentiation and mitochondrial OXPHOS. Early transcriptional upregulation of Gria gene translated into increased AMPAR protein levels at 48h in the DG and CA3 region and sustained higher AMPAR expression at 2 and 4 weeks post-FLASH. These findings support a durable activation of AMPAR. We propose a mechanism to explain FLASH-induced neuroprotection initiated by early calcium influx and subsequent sustained expression of glutamate receptor AMPAR in neurons and/or neural progenitors of the CA3, potentially contributing to long-term cognitive sparing. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/725423v1_ufig1.gif" ALT="Figure 1"> View larger version (59K): org.highwire.dtl.DTLVardef@1ae125forg.highwire.dtl.DTLVardef@138357aorg.highwire.dtl.DTLVardef@13f128dorg.highwire.dtl.DTLVardef@1db1cf6_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIFLASH-RT induces a stronger transcriptional response in the hippocampus than the cortex. C_LIO_LIFLASH-RT induces calcium signaling, LTP and mitochondrial OXPHOS genes. C_LIO_LIEarly AMPAR upregulation leads to sustained protein expression. C_LIO_LIFLASH-RT induces a AMPAR-dependent signaling program in CA3 neurons. C_LI

cancer biology↗

bioRxiv2026

Early microglial activation in the TME enables FLASH-RT to eradicate medulloblastoma while promoting neuron-astrocyte crosstalk to minimize toxicity in the hippocampus

BackgroundFLASH-RT defines a promising treatment modality against medulloblastoma, as it minimizes treatment-related complications. To support its clinical translation, we dissected the cellular and molecular determinants of the FLASH response in the tumor-microenvironment (TME) and healthy hippocampus using an orthotopic human medulloblastoma mouse model treated with a hypo-fractionated FLASH regimen. MethodsFive cohorts of 4 weeks-old UW228-MB-bearing female nude mice (n=57) were irradiated, or sham-irradiated using 3x10 Gy (BED=60), delivered 48h apart at 0.1 Gy/s (CONV) or 5.5x106 Gy/s (FLASH) using an electron beam (eRT6). Digital spatial profiling (DSP) was performed 24h after radiotherapy in one cohort, while the four other cohorts were followed for long-term tumor response, cognition, and neuroinflammation. ResultsBoth CONV and FLASH-RT induced a complete and long-lasting anti-tumor response in 100% of animals associated with cognitive decline. However, more mice maintained a very good discrimination score after FLASH exposure (38%) than CONV (7%). DSP revealed a sustained microglial activation in the cerebellar tumor micro-environment, where FLASH enhanced expression of genes with phagocytic and proteolytic activity. In the tumor free hippocampus, FLASH exposure induced a preferential neuron/astrocyte transcriptional crosstalk, which manifested over protracted times to minimize neuroinflammation and cognitive complications. ConclusionThe study shows the tumor-ablative efficacy of hypo-fractionated FLASH-RT in a human medulloblastoma mouse model. It is associated with qualitatively distinct transcriptional signatures prone to tumor and debris clearance mediated by microglial cells of the TME. Moreover, in the hippocampus, FLASH mitigates radiation-induced neurotoxicity by enhancing genes involved in synaptic plasticity, attenuating neuroinflammation, and preserving metabolic function. Key PointsO_LIComplete response of medulloblastoma and reduction of neurotoxicity with hypo-fractionated FLASH regimen. C_LIO_LIClearance-prone phagocytic and proteolytic activity in the microglia of the TME. C_LIO_LINeuron/astrocyte transcriptional crosstalk in the hippocampus. C_LI Importance of the studyThis study constitutes a milestone for the future implementation of FLASH-RT in the treatment of children with brain cancer. It shows that FLASH does not protect medulloblastoma and on the contrary can be ablative when delivered in 3 fractions of 10 Gy. FLASH promotes a metabolically active, phagocytosis-prone phenotype in microglial cells consistent with immune activation and tumor surveillance, in contrast to the proliferative and immunosuppressive signaling programs induced by CONV. It also shows how FLASH may differentially shape long-term brain function in patients with brain tumors by modifying the transcriptional program of hippocampal subregions known to be critical for memory encoding, pattern separation, and consolidation. In summary, this study supports the idea that FLASH has the potential to shift treatment paradigms and change the dismal therapeutic outcome in patients with brain cancer.

cancer biology↗

bioRxiv2026

Shared antimicrobial resistance gene families across gut microbiomes in indigenous Orang Asli communities of Peninsular Malaysia

Indigenous groups across the world have been underrepresented in the ongoing efforts to map human microbiome diversity. This study investigates the gut microbiome and resistome diversities of Indigenous Orang Asli communities in Malaysia with different lifestyles and degree of urbanisation. Healthy adult participants (>18 years old) were recruited from three Indigenous communities - Temuan (urban), Temiar (semi-urban), and Jahai (rural hunter-gatherer), as well as urban Malays. Stool samples were collected on dry ice and analysed using shotgun metagenomic sequencing. Microbial alpha diversity (Shannon) decreased but antibiotic resistance genes (ARGs) diversity increased as the degree of urbanisation in the groups increased (P < 0.05). The groups contributed to 13% of the variation observed in the microbial composition (PERMANOVA, P = 0.001), and 14.5% in resistome composition (PERMANOVA, P = 0.001). Romboutsia timonensis was significantly depleted in Jahai compared to Malay (FDR = 0.04). Shared ARGs conferring resistance to beta-lactams (cfxA), tetracyclines (tet), and macrolides (erm) were observed across all groups, irrespective of geographical location, ethnicity and lifestyle. This study provides initial characterisation of the gut microbiome and resistome of three Indigenous Orang Asli communities in Malaysia. Our findings offer foundational evidence of antimicrobial resistance patterns and underscores the need for broader inclusion of underrepresented populations in national surveillance and stewardship efforts. Impact statementOur study generated one of the first integrated microbiome-resistome analyses across an urbanisation gradient of Malaysian gut microbiome. Shotgun metagenomic profiling of hard-to-access Indigenous cohorts enabled taxonomic classification for most reads, supporting high-resolution microbial community and ARG analysis. Increasing urbanisation was associated with reduced microbial alpha diversity alongside increased ARG diversity, with population grouping explaining an insightful proportion of both microbiome and resistome variation. Core resistance determinants to beta-lactams (cfxA), tetracyclines (tet), and macrolides (erm) were consistently detected across lifestyles and geographies. These results establish a baseline framework for urbanisation-linked microbial shifts in the under-studied Malaysian gut microbiome and provide actionable direction for investigating national AMR drivers, surveillance design, and targeted stewardship strategies in underrepresented populations. Data summary and code availabilitySupporting data are provided in the supplementary data files. Specific accession numbers of the sequence data are provided as Supplementary Material. Codes produced for this analysis can be found at https://zenodo.org/records/18208358.

genomics↗

bioRxiv2025

Astrocytic glycolysis attenuates mitochondrial efficiency to preserve cognition

Astrocytic glycolysis is tightly coupled to neurotransmission and thought to be essential for neurological health. However, the metabolic adaptations that enable astrocytes to maintain a durable glycolytic profile without compromising viability are elusive. Here, using in vivo approaches including cell-specific gene expression disruption, metabolic flux analyses and behavioral tests in mice, we addressed this issue. We found that Pfkfb3 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3) is instrumental in maintaining the astrocytic glycolytic phenotype. Importantly, astrocytic glycolysis sustained by Pfkfb3 is required for normal cognitive performance. Mechanistically, ATP generated through glycolysis is consumed by mitochondria, via the reverse mode of ATP synthase, to conserve the proton gradient across the inner mitochondrial membrane. This enables mitochondria to attenuate pyruvate decarboxylation, tricarboxylic acid cycle and electron transport chain activity, thereby preserving pyruvate for conversion into lactate and delivery to neurons. These findings reveal that astrocytes sacrifice mitochondrial bioenergetic efficiency as a previously underappreciated strategy to support cognition.

cell biology↗

bioRxiv2025

Meta-analysis of the uncultured gut microbiome across 11,115 global metagenomes reveals a new candidate biomarker of health

The human gut microbiome plays an important biological role in host health, yet over 60% of gut species remain uncultured and hence inaccessible to experimental manipulation. Here we analysed 11,115 human gut metagenomes from 39 countries, 13 noncommunicable diseases and healthy individuals to understand the clinical relevance of the uncultured microbiome worldwide. We identified 317 uncultured species linked to distinct health states, with most microbiome signatures being disease specific. Uncultured bacteria were more abundant in healthy controls, with the genus CAG-170 predicted as the strongest biomarker of health. The genetic diversity and abundance of CAG-170 negatively correlated with gut microbiome imbalance over time, and ecological modelling identified it as the top candidate keystone genus among healthy populations globally. Functional prediction analysis showed CAG-170 species have greater capabilities for vitamin B12 biosynthesis but lack key genes involved in arginine production, offering new biological insights into this elusive genus. Our findings shed light on the underexplored role of uncultured gut species in health and disease.

microbiology↗

bioRxiv2025

Aeon: an open-source platform to study the neural basis of ethological behaviours over naturalistic timescales

Ethological behaviours are a powerful tool for neuroscience since they leverage the robust neural computations shaped by the species evolution to study the neural basis of cognitive functions. However, such behaviours are often transitory and dependent on factors that vary over space, time and number of individuals, making them difficult to capture with standard laboratory tasks. Here we present Aeon, an open-source platform designed for continuous, long-term study of self-guided behaviours in multiple mice and simultaneous recording of brain activity within large, customizable habitats. By integrating specialized modules for navigation, nesting and sleeping, escaping, foraging, and social interaction, Aeon enables the expression of key ethological behaviours while achieving experimental control and multi-dimensional quantifications from sub-millisecond to month-long durations. Its software architecture ensures robust data acquisition via many synchronized data streams and delivers a new standardised, unified data format that yields seamless, integrated analysis pipelines. Using assays such as digging-to-threshold and social foraging, Aeon reveals how mice adapt strategies in a changing environment and in response to conspecifics. Aeon bridges ecological relevance with rigorous experimental control to advance our understanding of how neural circuit activity gives rise to a range of highly conserved and adaptive behaviours.

neuroscience↗

bioRxiv2025

Host microbiome determines host specificity of the human whipworm, Trichuris trichiura

Long-term whipworm-host co-evolution has resulted in tropism for the caecum of specific hosts, an organ with the densest microbial population in the body. Here, we demonstrate that the host specificity of human whipworms (Trichuris trichiura) is host microbiome-driven. We successfully establish a T. trichiura infection in a non-primate host using a humanised-microbiota mouse model. We further show, in vitro, that hatching of T. trichiura was triggered by mucosal scrapings of the caecum of human microbiota-associated mice, but not from wild-type mice, which only induced T. muris hatching. Comparative metagenomic analysis of the murine versus humanised microbiomes directly implicated specific bacterial species in T. trichiura egg hatching. Additionally, we demonstrate that host tissue does not directly determine host specificity, as T. trichiura readily infected mouse caecaloids. Our findings indicate that host-microbiome-whipworm co-evolution has resulted in exquisite bacterial-whipworm egg interactions critical for hatching and development of these parasites in their definitive hosts.

microbiology↗

bioRxiv2025

Advancing Mobile Neuroscience: A Novel Wearable Backpack for Multi-Sensor Research in Urban Environments

The rapid global urbanisation has intensified the need to understand the complex interactions and impacts that city environments have on human physical or mental health and well-being. Traditional indoor laboratory-based approaches conduct experiments in well controlled settings but, while advantageous for their controlled conditions, they often lack ecological validity. To address this gap, we present the "eMOTIONAL Cities Walker Backpack" -- a wearable unit developed for synchronously collecting multi-modal data in dynamic real-world settings. Designed for both indoor and outdoor use, the backpack integrates environmental (for microclimate, air pollution and noise) and physiological sensors (including electroencephalography, eye-tracking and wrist-based biosensors for cardiovascular monitoring) to enable the study of human experience in naturalistic urban environments. In this paper, we describe the technical specifications and implementation of this technology during outdoor acquisitions across selected urban locations in the city of Lisbon. We also highlight its potential for methodological comparison with traditional lab-based tasks (particularly through the use of equivalent sensing technologies), and thus advancing the field of translational research in mental health and urban studies.

neuroscience↗

bioRxiv2025

Mice dynamically adapt to opponents in competitive multi-player games

Competing for resources in dynamic social environments is fundamental for survival and requires continuous monitoring of both self and others to guide effective choices. Yet most of our understanding of value-based decision-making comes from studying individuals in isolation, leaving open key questions about how animals adapt their strategies during social competition. Here, we developed an ethologically relevant multi-player game in which freely moving mice made valuebased decisions in a competitive spatial foraging task. We found that mice integrated real-time spatial information about both themselves and their opponents to flexibly shift their preferences toward safer, low-payout options when appropriate. Analyses of mice behaviour and reinforcement learning agents revealed that these adaptations could not be explained by simple reward learning, but were instead consistent with optimal decision strategies guided by opponent features. Using a dynamical model of decision-making, we found that competition increased choice variability and sensitivity to initial conditions, generating testable predictions for future neural recordings and perturbations. Together, our findings reveal a fundamental mechanism for flexible competitive foraging and propose novel frameworks for quantitatively understanding value-based decision-making in fast-changing social environments.

neuroscience↗

bioRxiv2025

From sporulation to village differentiation: the shaping of the social microbiome over rural-to-urban lifestyle transition in Indonesia

Despite established roles in human health and profound global diversity, existing gut microbiome datasets are biased toward Western urban cohorts, with especial under-representation of Southeast Asia. Here, we present a novel gut microbiome dataset from 116 Indonesians representing a cline from transitional hunter-gatherers to rural agricultural to urban lifestyles. We identify 1,304 species and 3,258 subspecies by assembling 11,070 metagenome-assembled genomes, revealing substantial species (15%) and subspecies level (50%) novelty. Novel taxa are rare, often village-specific, and depleted for sporulation genes, revealing a direct link between bacterial physiology, transmission, prevalence and discovery. We identify a rural-to-urban cline across multiple levels of biological organisation, from species abundance to microbiome composition and diversity. Furthermore, between-community, but not within-community, variation in diet is strongly predictive of microbiome composition, offering compelling evidence that microbiome divergence is driven by community-level differences. Our work highlights the interplay of host lifestyle, population structure and bacterial physiology in shaping microbiome diversity and biogeography, at the key scale of human communities.

microbiology↗

bioRxiv2024

Integration of metagenome-assembled genomes with clinical isolates reveals genomic signatures of Klebsiella pneumoniae in carriage and disease

Klebsiella pneumoniae is an opportunistic pathogen causing diseases ranging from gastrointestinal disorders to severe liver abscesses. While clinical isolates of K. pneumoniae have been extensively studied, less is known about asymptomatic variants colonizing the human gut across diverse populations. Genome-resolved metagenomics has offered unprecedented access to metagenome-assembled genomes (MAGs) from diverse host states and geographical locations, opening opportunities to explore health-associated microbial features. Here we analysed 662 human gut-derived K. pneumoniae genomes (319 MAGs, 343 isolates) from 29 countries to investigate the population structure and genomic diversity of K. pneumoniae in carriage and disease. Only 9% of sequence types were found to be shared between healthy and disease states, highlighting distinct diversity across health conditions. Integrating MAGs nearly doubled gut-associated K. pneumoniae phylogenetic diversity, and uncovered 86 lineages without representation among >20,000 Klebsiella isolate genomes from various sources. Genomic signatures linked to pathogenicity and carriage included those involved in antibiotic resistance, iron regulation, restriction modification systems and polysaccharide biosynthesis. Notably, machine learning models integrating MAGs and isolates more accurately classified disease and carriage states compared to isolates alone. These findings showcase the value of metagenomics to understand pathogen evolution with implications for public health surveillance strategies.

microbiology↗

bioRxiv2023

Weak neuronal glycolysis sustains cognition and organismal fitness

The energy cost of neuronal activity is mainly sustained by glucose1,2. However, in an apparent paradox, neurons only weakly metabolize glucose through glycolysis3,4,5,6, a circumstance that can be accounted for by the constant degradation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (Pfkfb3)3,7,8, a key glycolysis-promoting enzyme. To evaluate the in vivo physiological significance of this hypo-glycolytic metabolism, here we genetically engineered mice with their neurons transformed into active glycolytic cells through Pfkfb3 expression. In vivo molecular, biochemical, and metabolic flux analyses of these neurons revealed an accumulation of anomalous mitochondria, complex I disassembly, bioenergetic deficiency and mitochondrial redox stress. Notably, glycolysis-mediated NAD+ reduction impaired sirtuin-dependent autophagy. Furthermore, these mice displayed cognitive decline and a metabolic syndrome that was mimicked by confining Pfkfb3 expression to hypothalamic neurons. Neuron-specific genetic ablation of mitochondrial redox stress corrected these alterations. Thus, the weak glycolytic nature of neurons is required to sustain higher-order organismal functions.

cell biology↗

bioRxiv2023

Dosimetric and biologic intercomparison between electron and proton FLASH beams

Background and purposeThe FLASH effect has been validated in different preclinical experiments with electrons (eFLASH) and protons (pFLASH) operating at a mean dose rate above 40 Gy/s. However, no systematic intercomparison of the FLASH effect produced by e vs. pFLASH has yet been performed and constitutes the aim of the present study. Materials and methodsThe electron eRT6/Oriatron/CHUV/5.5 MeV and proton Gantry1/PSI/170 MeV were used to deliver conventional (0.1 Gy/s eCONV and pCONV) and FLASH ([≥]100 Gy/s eFLASH and pFLASH) irradiation. Protons were delivered in transmission. Dosimetric and biologic intercomparisons were performed with previously validated models. ResultsDoses measured at Gantry1 were in agreement ({+/-} 2.5%) with reference dosimeters calibrated at CHUV/IRA. The neurocognitive capacity of e and pFLASH irradiated mice was indistinguishable from the control while both e and pCONV irradiated cohorts showed cognitive decrements. Complete tumor response was obtained with the two beams and was similar between e and pFLASH vs. e and pCONV. Tumor rejection was similar indicating that T-cell memory response is beam-type and dose-rate independent. ConclusionDespite major differences in the temporal microstructure, this study shows that dosimetric standards can be established. The sparing of brain function and tumor control produced by the two beams were similar, suggesting that the most important physical parameter driving the FLASH effect is the overall time of exposure which should be in the range of hundreds of milliseconds for WBI in mice. In addition, we observed that immunological memory response is similar between electron and proton beams and is independent off the dose rate.

cancer biology↗

bioRxiv2023

Development of a Plasmodium vivax biobank for functional ex vivo assays

BackgroundPlasmodium vivax is the second most prevalent cause of malaria yet remains challenging to study due to the lack of a continuous in vitro culture system, highlighting the need to establish a biobank of clinical isolates with multiple freezes per sample for use in functional assays. Different methods for cryopreserving parasite isolates were compared and subsequently the most promising one was validated. Enrichment of early- and late-stage parasites and parasite maturation were quantified to facilitate assay planning. MethodsIn order to compare cryopreservation protocols, nine clinical P. vivax isolates were frozen with four glycerolyte-based mixtures. Parasite recovery post thaw, post KCl-Percoll enrichment and in short-term in vitro culture was measured via slide microscopy. Enrichment of late-stage parasites by magnetic activated cell sorting (MACS) was measured. Short and long-term storage of parasites at either -80{degrees}C or liquid nitrogen were also compared. ResultsOf the four cryopreservation mixtures, one mixture (glycerolyte:serum:RBC at a 2.5:1.5:1 ratio) resulted in improved parasite recovery and statistically significant (P<0.05) enhancement in parasite survival in short-term in vitro culture. A parasite biobank was subsequently generated using this protocol resulting in a collection with 106 clinical isolates, each with 8 vials. The quality of the biobank was validated by measuring several factors from 47 thaws: the average reduction in parasitemia post-thaw (25.3%); the average fold enrichment post KCl-Percoll (6.65-fold); and the average percent recovery of parasites (22.0%, measured from 30 isolates). During short-term in vitro culture, robust maturation of ring stage parasites to later stages (>20% trophozoites, schizonts and gametocytes) was observed in 60.0% of isolates by 48 hours. Enrichment of mature parasite stages via MACS showed good reproducibility, with an average 30.0% post-MACS parasitemia and an average 5.30 x 105 parasites/vial. Finally, the effect of storage temperature was tested, and no large impacts from short-term (7 day) or long term (7 - 10 year) storage at -80{degrees}C on parasite recovery, enrichment or viability was observed. ConclusionsHere, an optimized freezing method for P. vivax clinical isolates is demonstrated as a template for the generation and validation of a parasite biobank for use in functional assays.

microbiology↗

bioRxiv2022

Hypoxic tumors are sensitive to FLASH radiotherapy

Tumor hypoxia is a major cause of resistance to cancer treatments and especially to radiotherapy (RT) and we wanted to assess whether ultra-high dose rate FLASH RT could overcome this resistance. We engrafted tumor cells of various origins subcutaneously in mice to provide a reliable and rigorous way to modulate oxygen supply via vascular clamping or carbogen breathing. We irradiated tumors using a single 20 Gy fraction at either conventional (CONV) or FLASH dose-rate. Using multiple different subcutaneous tumor models, and in contrast CONV-RT, FLASH-RT retained anti-tumor efficacy under extreme hypoxia. These findings demonstrate that in addition to normal tissue sparing, FLASH-RT overcomes hypoxia-mediated tumor resistance. Follow-up molecular analysis using RNAseq profiling uncovered FLASH-specific inhibition of cell proliferation and translation as well as metabolic shifts that discriminated FLASH-RT from CONV-RT. These data provide new and specific insights into the mechanism of action and identify novel targets for intervention.

cancer biology↗

bioRxiv2022

Mitochondrial sodium/calcium exchanger NCLX regulates glycolysis in astrocytes, impacting on cognitive performance

Intracellular Ca2+ concentrations are strictly controlled by plasma membrane transporters, the endoplasmic reticulum, and mitochondria, in which Ca2+ uptake is mediated by the mitochondrial calcium uniporter complex (MCUc), while efflux occurs mainly through the mitochondrial Na+/Ca2+ exchanger (NCLX). RNAseq database repository searches led us to identify the Nclx transcript as highly enriched in astrocytes when compared to neurons. To assess the role of NCLX in mouse primary culture astrocytes, we inhibited its function both pharmacologically or genetically. This resulted in re-shaping of cytosolic Ca2+ signaling and a metabolic shift that increased glycolytic flux and lactate secretion in a Ca2+-dependent manner. Interestingly, in vivo genetic deletion of NCLX in hippocampal astrocytes improved cognitive performance in behavioral tasks, whereas hippocampal neuron-specific deletion of NCLX impaired cognitive performance. These results unveil a role for NCLX as a novel modulator of astrocytic glucose metabolism, impacting on cognition.

biochemistry↗