Biology subjects

Rodriguez, R.

Publications and source records attributed to Rodriguez, R..

At least 19 recordsLinked to original sources

bioRxiv2026

Ancient Mitogenomes from Belize Provide Insights into the Mobility and Migration of Ancient Communities in Mesoamerica and the Caribbean.

Maya peoples have undergone several largescale demographic transformations over the past 3000 years, including the formation and depopulation of large urban centers, climatic events, and multiple colonial regimes. Archaeological and stable isotope evidence from across the Maya lowlands throughout these periods paints a picture of a demographically mobile population with complex and dynamic relationships among some of the largest urban polities in antiquity. The nature of the genomic relationship between ancient Maya urban centers, as well as their relationship with present-day Maya communities, however, remains under-characterized. Here, we present mitogenomic data of 16 ancient Maya Ancestors recovered from interments in the ancient Maya cities of Caracol and Santa Rita Corozal located in Western and Northern Belize. These ancient data were combined with 110 newly collected contemporary individuals from Northern Belize, along with nearly 600 previously published ancient and contemporary comparative mitogenomes recovered from sites spanning Mesoamerica and the Caribbean to reconstruct paleodemographic and mobility patterns of maternal lineages through time. Our results are consistent with broadly interconnected Maya populations that have maintained maternal genetic continuity across much of the Holocene, and which are not structured by linguistic family.

genetics↗

bioRxiv2026

Inhibiting nociceptor endocytosis reduces MIA-induced osteoarthritic pain behavior

Introduction: Osteoarthritis (OA) is a degenerative joint condition characterized by chronic pain and the need for pain management. Locally targeting the endocytotic AP2 complex in nociceptors presents a potential strategy for providing sustained pain relief in individuals with OA. Objective: We investigated whether pain behavior associated with OA can be mitigated by genetically silencing the AP2alpha2 subunit of the AP2 complex in nociceptors and by pharmacologically inhibiting the AP2 complex through the intraarticular administration of a small lipidated decoy peptide. Method: Monoiodoacetate (MIA) was employed to induce knee joint OA in mice and rats. Pain behavior was assessed using dynamic weight-bearing and von Frey filaments. Upon confirmation of established OA pain behavior, in vivo AP2alpha2 genetic knockdown in mice was achieved through sciatic nerve transfection of a targeting AP2alpha2 short hairpin RNA (shRNA). To pharmacologically target endocytosis, a single intraarticular injection of peptide was administered into the arthritic knee of rats. The injection contained either the AP2 inhibitor peptide or a scrambled peptide control. Results: Pain behavior was significantly reduced after both genetic and pharmacological disruption of AP2-driven endocytosis. Animals treated with the Ap2 inhibitor peptide exhibited reduced pain behavior throughout the 28-day assay period. Following the completion of behavioral testing, arthritic knee joints and contralateral healthy knee joints were subsequently collected to assess the impact of the treatment on disease progression. Micro-computed tomography analysis revealed a preservation of bone volume in the arthritic joints that received the AP2 inhibitor peptide treatment, in contrast to the scrambled peptide group. Conclusion: These findings demonstrate that the inhibition of nociceptor endocytosis by a small lipidated peptide presents a promising approach to provide sustained relief from joint pain in individuals with arthritis.

pharmacology and toxicology↗

bioRxiv2026

Physiological limits of localized hypothermia in the human cochlea: The role of vascular heat transport

PurposeMild therapeutic hypothermia (MTH) preserves cochlear function in animal models and is now entering early-phase human trials for hearing preservation. However, the extent to which the human cochlea can actually be cooled, and the mechanisms underlying MTH, remain unclear, in part because blood perfusion is expected to oppose localized cooling. In this study we evaluated the impact of blood flow on human cochlear temperature exposed to the MTH device using a combined experimental and computational approach. MethodsTemperature measurements were obtained from a human cadaver skull exposed to a commercial MTH device. These data were used to validate a three-dimensional bioheat transfer model incorporating realistic skull anatomy. The validated model was subsequently extended to include physiological blood perfusion in the internal carotid artery; a major heat source located near the cochlea. Finally, the in silico model was further expanded to incorporate the surrounding skin and brain tissues. ResultsIncorporating blood flow in internal carotid artery substantially altered predicted cochlear temperature distributions, highlighting the importance of localized vascular heat transport in the human cochlea during MTH. Although cochlear cooling was attenuated in the presence of perfusion, the therapeutic effects of MTH may not depend solely on the magnitude of local intracochlear temperature reduction. Additional mechanisms, such as reduced facial surface temperature, may also contribute to its efficacy. ConclusionThe validated in silico model provides a physiologically realistic framework for evaluating human cochlear thermal responses, investigating MTH mechanisms, and optimizing temperature-based strategies for hearing preservation.

bioengineering↗

bioRxiv2026

The Incremental Cluster Threshold-Free Cluster Enhancement Algorithm for Functional Connectivity Analysis

Threshold-free cluster enhancement (TFCE) is one of the most used statistical inference methods in neuroimaging, but its computational cost limits some of its applications. The current implementations recompute clusters at each threshold step, creating computation costs that poorly scale with precision increases. Furthermore, as larger samples and reduced noise increase maximum t-statistics, computational burden grows correspondingly. As the field moves towards finer parcellations, the number of FC edges grows quadratically with the number of ROIs, making TFCE computationally infeasible at the scales increasingly demanded by the field. We present Incremental Cluster TFCE (IC-TFCE), an algorithm that produces numerically equivalent results to standard TFCE while decoupling runtime from discretization precision. The IC-TFCE builds clusters incrementally from previous threshold steps rather than recomputing them, stores TFCE results on a region of interest (ROI) based structure instead of a functional connectivity (FC) edge structure for improved speed, and can be applied to voxel data through a novel graph transformation described and validated herein. This algorithm achieves a measured 3-93x speedup for FC TFCE depending on the precision parameter dh, making TFCE analyses with fine parcellations of 1000 or more ROIs computationally tractable for the first time. Finally, we validate correctness through mathematical proof and numerical comparison. The efficiency provided by IC-TFCE allowed a large-scale empirical power analysis across dh values to guide practitioners in parameter selection for their analyses.

neuroscience↗

bioRxiv2026

PATIENT-DERIVED ORGANOIDS CAPTURE HISTOLOGICAL, MOLECULAR AND THERAPEUTIC HETEROGENEITY IN PHARYNGEAL AND LARYNGEAL SQUAMOUS CELL CARCINOMAS

BackgroundHead and neck squamous cell carcinoma (HNSCC) comprises a heterogeneous group of epithelial malignancies associated with poor survival ({approx}50%), limited therapeutic options, and a lack of predictive biomarkers. Concurrent chemoradiotherapy (CRT) remains the standard treatment for advanced disease; however, many patients fail to respond, develop resistance, or eventually relapse. The development of three-dimensional organoid technology has enabled the generation of patient-derived organoids (PDOs), offering a promising platform for personalized therapeutic testing. MethodsWe established a biobank of HNSCC PDOs from fresh laryngeal and pharyngeal tumor samples, including human papillomavirus-positive (HPV+) cases. Organoid formation and expansion rates were analyzed in relation to clinical parameters. Selected representative PDOs were histologically and molecularly characterized. Additionally, several models were exposed to cisplatin and radiation to evaluate treatment response, and a subset was assessed for tumorigenicity in subcutaneous mouse models. ResultsFifty-seven PDO models were successfully established, long-term expanded, and cryopreserved. Prior chemotherapy and/or radiotherapy was identified as an independent negative predictor of organoid outgrowth and expansion capacity compared with treatment-naive samples. Histological features, including differentiation grade and immunohistochemical markers, were largely preserved and strongly correlated with the original tumors. PDOs displayed heterogeneous responses to cisplatin and radiotherapy, with HPV-positive models showing greater sensitivity, consistent with clinical observations. Global transcriptomic profiling revealed molecular subtypes concordant with established HNSCC classifications and suggested an additional subtype characterized by low MYC and mTORC1 transcriptional activity. ConclusionHNSCC PDOs faithfully recapitulate tumor histology and molecular diversity, providing a robust platform to investigate tumor biology and therapeutic response.

cancer biology↗

bioRxiv2026

A minimal transcriptomic signature predicts intravascular tumor extension in renal cell carcinoma

Renal cell carcinoma (RCC) with venous tumor thrombus, termed renal intravascular tumor extension (RITE), is associated with aggressive behavior and poor clinical outcomes. Yet, its underlying molecular determinants remain incompletely defined. We analyzed RNA sequencing data from three independent RCC cohorts comprising 721 samples. Two cohorts included matched samples of index tumor, tumor thrombus, and normal adjacent kidney tissue. Analyses integrated dimensionality reduction, differential gene expression, interpretable machine learning, and gene ontology approaches. Principal component analysis revealed that only these two cohorts exhibited a coherent RITE-associated transcriptional structure. Their sequencing depth was sufficient to delineate 6,317 differentially expressed genes that distinguish RITE from non-RITE tumors. SHAP-based feature attribution across logistic regression, random forest, and XGBoost yielded a robust 29-gene consensus signature, which was further distilled into a compact 13-gene panel that preserved maximal classification performance. These genes converged on biological themes, including loss of distal epithelial identity, dysregulation of ion transport pathways, and consistent enrichment of mitochondrial processes such as oxidative phosphorylation. Together, these findings define a newly discovered and uniquely refined molecular signature of venous tumor extension in RCC and highlight mechanistically relevant pathways that may inform biomarker development and future translational strategies for predicting or mitigating RITE progression.

cancer biology↗

bioRxiv2025

A multi-tiered microDicer with hierarchical blades achieves protein-preserving microdissection down to 10 microns

To study tissue heterogeneity at the sub-millimeter scale, laser capture microdissection (LCM) has been the leading technology for isolating regions of interest (ROI) for downstream molecular profiling. As the ROI approaches cellular dimensions ([~]10 m), laser-induced photothermal damage and challenges in capturing microtissues in conventional LCM can compromise protein preservation and quantitative fidelity. This work introduces multi-tiered Dicers, fabricated by two-photon polymerization, to mechanically dissect tissue slices into uniform microtissues down to 10 m. The hierarchical blade architecture limits instantaneous blade-tissue engagement and lowers the cutting force relative to single-tier designs. For benchmarking, proteomic analysis is performed on ethanol-fixed human squamous cell carcinoma microtissues generated by Dicers and by LCM. Under identical Nanodroplet Processing in One pot for Trace Samples (nanoPOTS) and liquid chromatography-mass spectrometry (LC-MS) conditions, Dicers yield more peptides and proteins than LCM, with the largest gains at 10-20 m spatial resolution. Confocal imaging shows catapult-associated cavities in LCM-generated microtissues. This material loss, along with membrane-limited protein extraction, likely reduces protein coverage. In contrast, multi-tiered Dicers enables reproducible microdissection down to 10 m while maintaining high protein coverage. With spatial registration of microtissues under development, Dicers have potential to complement LCM for next-generation spatial proteomic workflows.

bioengineering↗

bioRxiv2025

Plasma plasmalogen levels and risk of lymph node positive breast cancer

Lymph node involvement is a key predictor of poor breast cancer prognosis. Systemic lipid alterations can contribute to cancer cell survival in lymph nodes, but their relevance in humans remains unclear. Here, we combine human epidemiologic analyses from the Nurses Health Study 2 and complementary mechanistic studies in mouse models to investigate how systemic lipid profiles relate to lymph node positive breast cancer. We show that in pre-diagnostic human plasma (n=511), lower levels of phosphatidylethanolamine (PE) and phosphatidylcholine (PC)-enriched plasmalogens are associated with increased risk of lymph node positivity, with stronger associations in samples collected closer to diagnosis. Consistent with the human data, lower levels of PE and PC-enriched plasma plasmalogens are found in mice with nodal involvement. Furthermore, in mice, dietary PUFA depletion reduces lipid oxidation in breast cancer cells in lymph nodes and promotes their survival and metastatic spread. These findings suggest that reduced levels of PE and PC-plasmalogens and decreased PUFA availability creates a lipid environment that enables breast cancer lymph node involvement.

cancer biology↗

bioRxiv2025

Sodium Aurothiomalate Induces Ferroptosis by Targeting GPX4 via Gold-Dependent Thiomalate Covalent Modification

Ferroptosis, an iron-dependent form of oxidative cell death, is predominantly regulated by glutathione peroxidase 4 (GPX4), making it a promising target for cancer therapy. However, the majority of GPX4 inhibitors, most of which contain a chloroacetamide moiety such as RSL3, are limited by poor pharmacokinetic properties and off-target effects, hindering their preclinical translation. Utilizing a range of interdisciplinary methodologies, we show that sodium aurothiomalate (ATM), a drug approved by many agencies, induces ferroptosis by covalently targeting GPX4 via formation of a selenenylsulfide bond. In preclinical models of neuroblastoma and acute myeloid leukemia (AML), ATM combined with ferric ammonium citrate (FAC) yields a synergistic effect, resulting in a significant reduction in tumor growth. Mechanistically, ATM disrupts GPX4 activity by covalently binding thiomalate to the active site selenocysteine, while modification of specific cysteine residues leads to destabilization of the protein and impaired binding to phospholipids. We propose that these covalent modifications are achieved through a unique reaction mechanism, in which the gold component of ATM acts as a thiol-masking carrier and is only transiently present, being subsequently displaced and allowing the reaction of the thiomalate moiety with the target selenocysteine or cysteine. Our data lay the foundation for development of novel, drug-like thiol-based GPX4 inhibitors.

biochemistry↗

bioRxiv2025

Curing autoimmune diabetes with islet and hematopoietic cell transplantation after CD117 antibody-based conditioning

Mixed hematopoietic chimerism after allogeneic hematopoietic cell transplantation (HCT) promotes tolerance of transplanted donor-matched solid organs, corrects autoimmunity, and could transform therapeutic strategies for autoimmune type 1 diabetes (T1D). However, development of non-toxic bone marrow conditioning protocols is needed to expand clinical use. We developed a chemotherapy-free, non-myeloablative (NMA) conditioning regimen that achieves mixed chimerism and allograft tolerance across MHC barriers in NOD mice. We obtained durable mixed hematopoietic chimerism in prediabetic NOD mice using anti-c-Kit monoclonal antibody, T-cell depleting antibodies, JAK1/2 inhibition, and low-dose total body irradiation prior to transplantation of MHC-mismatched B6 hematopoietic cells, preventing diabetes in 100% of chimeric NOD:B6 mice. In overtly diabetic NOD mice, NMA conditioning followed by combined B6 HCT and islet transplantation durably corrected diabetes in 100% of chimeric mice without chronic immunosuppression or graft-versus-host disease (GVHD). Chimeric mice remained immunocompetent, as assessed by blood count recovery and rejection of 3rd party allogeneic islets. Adoptive transfer studies and analysis of autoreactive T cells confirmed correction of autoimmunity. Analysis of chimeric NOD mice revealed central thymic deletion and peripheral tolerance mechanisms. Thus, with NMA conditioning and cell transplantation, we achieved durable hematopoietic chimerism without GVHD, promoted islet allograft tolerance, and reversed established T1D. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=197 SRC="FIGDIR/small/673576v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@23fcdorg.highwire.dtl.DTLVardef@1aac97borg.highwire.dtl.DTLVardef@191e06forg.highwire.dtl.DTLVardef@25be2b_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

Polyamines buffer labile iron to suppress ferroptosis

Polyamines are essential and evolutionarily conserved metabolites present at millimolar concentrations in mammalian cells. Cells tightly regulate polyamine homeostasis through complex feedback mechanisms, yet the precise role necessitating this regulation remains unclear. Here, we show that polyamines contribute to endogenous buffering of redox-active iron, providing a molecular link between polyamine metabolism and ferroptosis. Using a genome-wide CRISPR screen, we identified a synthetic lethal dependency between polyamine depletion and the key ferroptosis suppressor, GPX4. Mechanistically, we show that polyamine deficiency triggers a redistribution of cellular iron, increasing the labile iron pool and upregulating ferritin. To directly visualize this iron buffering in living cells, we developed a genetically encoded fluorescent reporter for redox-active iron. Live-cell analysis revealed a striking inverse correlation between intracellular polyamine levels and redox-active iron at single-cell resolution. These findings reposition polyamines as key regulators of iron homeostasis, with implications for ferroptosis-linked disease states and cellular redox balance.

cell biology↗

bioRxiv2025

Improved conditioning for hematopoietic chimerism induces islet tolerance to cure diabetes

Mixed hematopoietic chimerism after hematopoietic cell transplantation (HCT) can modulate the immune system and induce tolerance to allogeneic tissues. However, bone marrow conditioning-related toxicities preclude wider adoption of HCT for transplant allotolerance. We sought agents that reduced conditioning intensity, while promoting durable mixed chimerism after HCT across complete major histocompatibility complex (MHC) mismatch in diabetic mice, permitting islet allotransplantation and diabetes reversal. We systematically tested baricitinib (JAK1/2 inhibitor), venetoclax (Bcl2 inhibitor), and CD47 antibody, agents in current clinical use, and quantified hematopoietic chimerism after HCT. Combined with CD117 antibody, transient T cell depletion, and just 10 centigray (cGy) total body irradiation (TBI), these agents enabled durable mixed chimerism and matching allo-islet tolerance, to cure diabetes without evidence of GVHD. Thus, we have developed a conditioning regimen to promote allogeneic mixed hematopoietic chimerism and transplanted islet allotolerance that minimizes conditioning radiation and cures diabetes, a significant achievement.

immunology↗

bioRxiv2025

Localization of AP2α2, TRPV1 and PIEZO2 to the Large Dense Core Vesicles of Human Dorsal Root Ganglion Neurons

Dorsal Root Ganglia (DRG) consist of both peptidergic and non-peptidergic nociceptive neurons. CGRP, an inflammatory neuropeptide, is a classical marker of peptidergic nociceptors and CGRP is stored within the large dense core vesicles (LDCVs) of these neurons. In addition to storing large peptide neurotransmitters, LDCVs might also serve to transport key membrane proteins to the peripheral terminals. This immunohistochemical study investigated the localization of different membrane proteins to the LDCVs of human DRG neurons. Previously validated antibodies against the endocytotic subunit AP22, the heat-activated channel TRPV1 and the mechanosensitive channel PIEZO2 were used in conjunction with an antibody against CGRP on sections of intact human DRG isolated from de-identified human subjects. Immunohistochemical studies were also performed on human synovial tissue to examine peripheral terminals. High magnification confocal microscopy was used to determine the co-localization signal of these membrane proteins with CGRP. We observed a strong co-localization of AP22 with the CGRP containing LDCVs signifying its role in membrane recycling. Moreover, we also observed a strong colocalization of TRPV1 and PIEZO2 with CGRP suggesting that LDCV release controls the trafficking of these channels to the membrane. It is likely that during injury, bulk exocytosis of CGRP will concomitantly increase the surface expression of TRPV1 and PIEZO2 channels enhancing the responsiveness of these neurons to painful stimuli. This model suggests that neurons that co-localize TRPV1 and PIEZO2 to CGRP containing LDCVs are likely silent nociceptors.

neuroscience↗

bioRxiv2025

14-3-3ϵ UFMylation promotes RIG-I-mediated signaling

Post-translational modifications regulate RIG-I signaling in diverse ways. We previously showed that UFMylation, the covalent attachment of the ubiquitin-fold modifier UFM1 to proteins, enhances RIG-I signaling by promoting its interaction with its membrane-targeting adaptor 14-3-3{varepsilon}. Here, we map UFM1 conjugation to lysines K50 and K215 on 14-3-3{varepsilon} and demonstrate how these UFMylation events control RIG-I signaling. Using in vitro and cellular UFMylation assays, we reveal that K50R/K215R mutations abolish UFMylation and reduce type I and III interferon induction following RIG-I activation. Unexpectedly, these mutations do not disrupt 14-3-3{varepsilon}-RIG-I interaction. Instead, they paradoxically enhance RIG-I interaction with MAVS while simultaneously reducing 14-3-3{varepsilon}-MAVS interaction. These findings establish UFMylation of 14-3-3{varepsilon} as an important control that shapes MAVS complex architecture to ensure optimal RIG-I signaling and highlights the broader regulatory role of UFMylation in antiviral innate immunity. ImportancePost-translational modifications provide regulatory control of antiviral innate immune responses. Our study reveals that UFMylation of 14-3-3{varepsilon} is required for RIG-I-mediated innate immune signaling. We demonstrate that conjugation of UFM1 to specific lysine residues on 14-3-3{varepsilon} enhances downstream signaling events that facilitate interferon induction. It does this by stabilizing 14-3-3{varepsilon} association with the MAVS signaling complex and coordinating productive complex architecture. By identifying the precise sites of UFMylation on 14-3-3{varepsilon} and their functional consequences, we provide insights into the regulatory layers governing antiviral innate immunity. These findings complement emerging evidence that UFMylation serves as a versatile modulator across diverse immune pathways. Furthermore, our work highlights how protein chaperones like 14-3-3{varepsilon} can be dynamically modified to orchestrate complex signaling cascades, suggesting potential therapeutic approaches for targeting dysregulated innate immunity.

immunology↗

bioRxiv2025

A small lipidated peptide targeting NaV1.8 channels attenuates osteoarthritic pain behavior and prevents bone erosion

Chronic pain is a major concern for patients with osteoarthritis (OA). Current treatments for OA-related pain often fail and may worsen the disease. The sodium channel subtype NaV1.8 has emerged as a potential target for treating pain, leading to the development of NaV1.8 inhibitors in clinical trials. We previously identified Magi-1, a WW domain-containing scaffold protein, as a regulator of NaV1.8 at the plasma membrane of nociceptive neurons. Disrupting the interaction between NaV1.8 and Magi-1 facilitated channel degradation in neurons, reducing pain behavior in multiple animal models. In this study, we investigated the impact of disrupting NaV1.8 scaffolding on an animal model of OA pain using genetic and pharmacological approaches. Genetic Magi-1 knockdown effectively attenuated established OA pain in mice. Pharmacological targeting of the NaV1.8-Magi-1 interaction in rats with a lipidated NaV1.8 WW binding domain decoy peptide inhibited pain behavior for multiple weeks. MicroCT imaging revealed minimal alterations in subchondral bone remodeling in animals injected with the lipidated decoy peptide compared to those receiving scrambled peptide-control animals. This suggested that the NaV1.8 peptidomimetic not only alleviated OA pain but also delayed joint degeneration. Our preclinical studies indicate that intraarticular injection of lipidated peptides capable of disrupting ion channel scaffolding in neurons can provide effective and sustained analgesia for several weeks after a single administration.

pharmacology and toxicology↗

bioRxiv2025

Light-induced conformational switching and magnetic sensitivity of Drosophila cryptochrome

Cryptochromes are flavoproteins with a number of established and proposed biological functions based on their sensitivity to light. Amongst the latter is the possibility that cryptochromes mediate the geomagnetic compass sense used by migratory birds as a navigational cue. This hypothesis rests on a magnetically sensitive photochemical reaction of the flavin chromophore in which a series of electron transfers within the protein scaffold ultimately generates a signal propagated within the central nervous system of the animal. Although there is a good understanding of the photochemistry and the electron transfer pathway, the protein-mediated mechanisms of signal transduction are still unclear. Here we have examined the response of Drosophila melanogaster cryptochrome - DmCRY, an archetypal cryptochrome - to photochemical activation by means of molecular dynamics simulations, hydrogen-deuterium exchange mass spectrometry, and cavity ring-down spectroscopy. We were able to measure the dynamics of DmCRY at near-residue level resolution, revealing a reversible, long-lived, blue-light induced conformational change in the C-terminal tail of the protein. This putative signalling state was validated using different illumination conditions, and by examining DmCRY variants in which the electron transfer chain was disrupted by point mutation. Our results show how the photochemical behaviour of the flavin chromophore generates a state of DmCRY that may act as a key primer for modulating downstream interactions.

biophysics↗

bioRxiv2024

Reactive Oxygen Detoxification Contributes to Mycobacterium abscessus Antibiotic Survival

When a population of bacteria is exposed to a bactericidal antibiotic, most cells die rapidly. However, a sub-population of antibiotic-tolerant cells known as "persister cells" can survive for prolonged periods. In addition, antibiotic tolerance can be broadly induced throughout the population by stresses such as nutrient deprivation. However, the pathways required to maintain viability in this setting, and how stress induces antibiotic tolerance are both poorly understood. To identify genetic determinants of antibiotic tolerance in mycobacteria, we carried out transposon mutagenesis insertion sequencing (Tn-Seq) screens in Mycobacterium abscessus (Mabs) exposed to bactericidal translation-inhibiting antibiotics. This analysis identified genes essential for the survival of both spontaneous persister cells as well as for stress-induced tolerance, allowing the first genetic comparison of these states in mycobacteria. Pathway analysis identified multiple genes involved in the detoxification of reactive oxygen species (ROS), including the catalase-peroxidase katG, which contributed to survival in both unstressed and nutrient-starved cells. In addition, we found that endogenous ROS were generated by translation-inhibiting antibiotics, and that hypoxia impaired bacterial killing. KatG specifically contributed to survival following exposure to transcription or translation inhibitors, but not other antibiotic classes tested. Thus, the lethality of some antibiotics is amplified by toxic ROS accumulation, and antibiotic-tolerant cells require detoxification systems to remain viable. These findings further demonstrate that antibiotic-induced ROS plays a broad role in mediating antibiotic lethality across diverse organisms.

microbiology↗

bioRxiv2024

Ether lipids influence cancer cell fate by modulating iron uptake

Cancer cell fate has been widely ascribed to mutational changes within proteincoding genes associated with tumor suppressors and oncogenes. In contrast, the mechanisms through which the biophysical properties of membrane lipids influence cancer cell survival, dedifferentiation and metastasis have received little scrutiny. Here, we report that cancer cells endowed with high metastatic ability and cancer stem celllike traits employ ether lipids to maintain low membrane tension and high membrane fluidity. Using genetic approaches and lipid reconstitution assays, we show that these ether lipid-regulated biophysical properties permit non-clathrin-mediated iron endocytosis via CD44, resulting in significant increases in intracellular redox-active iron and enhanced ferroptosis susceptibility. Using a combination of in vitro threedimensional microvascular network systems and in vivo animal models, we show that loss of ether lipids from plasma membranes also strongly attenuates extravasation, metastatic burden and cancer stemness. These findings illuminate a mechanism whereby ether lipids in carcinoma cells serve as key regulators of malignant progression while conferring a unique vulnerability that can be exploited for therapeutic intervention.

cancer biology↗