Biology subjects

Talbot, P.

Publications and source records attributed to Talbot, P..

14 recordsLinked to original sources

bioRxiv2026

F1F0-ATP-synthase subunit b head-to-head interactions shape intracellular membranes in Escherichia coli

1Intracellular membrane (ICM) compartments in bacteria remain poorly understood. In Escherichia coli, ICMs form upon the overproduction of certain membrane proteins. Here, we investigate at the molecular level how overproduction of subunit b of the F1Fo-ATP synthase complex shapes ICMs. Through a combination of subunit b deletions, electron microscopy, and biochemical analyses, we demonstrate that ICMs network structuration is mediated by the C-terminal domain of subunit b. High-resolution cryo-electron tomography and molecular dynamics simulations reveal that this domain forms tetrameric assemblies, bridging membranes and maintaining a regular 26 nm spacing. Transcriptomic and proteomic analyses further show that the cell responds to ICMs formation by upregulating energy metabolism genes and the ESCRT-III homolog PspA, while downregulating ribosomal and translational machinery. These results uncover a novel mechanism by which the C-terminal domain of subunit b drives the structuring of intracellular membranes. Additionally, they highlight how E. coli adapts to membrane stress by overexpressing membrane-remodeling proteins, a response that shares similarities with intracellular membrane homeostasis mechanisms in photosynthetic bacteria and unicellular algae.

microbiology↗

bioRxiv2025

Susceptibility of Human Neural Stem Cells to SARS-CoV-2: Entry Mechanisms and Glycocalyx Influence

Previous work demonstrated that ectodermal cells exhibit greater susceptibility to SARS-CoV-2 infection than endodermal and mesodermal cells, raising concerns about potential vulnerability of the developing nervous system. We hypothesized that neural stem cells (NSCs) derived from human ectoderm are susceptible to SARS-CoV-2 infection. Using pseudotyped viral particles representing both wild-type and Omicron spike variants, we confirmed efficient infection of NSCs, with Omicron variants preferentially utilizing endocytosis-mediated entry. Inhibition of endocytosis with filipin and OcTMAB significantly reduced infection across all spike variants. Low glycosylation levels on NSCs facilitated viral entry, and enzymatic removal of glycosylation increased their susceptibility. Ectodermal infection by SARS-CoV-2 raises serious concern for potential teratogenic effects on the nervous system, possibly causing latent or subclinical anomalies not immediately evident at birth. Therefore, future clinical studies and long-term surveillance of infants and children exposed in utero are necessary to investigate and identify potential neurodevelopmental deficits.

developmental biology↗

bioRxiv2025

Electronic Cigarette Aerosol Exposure Induces Airway Remodeling in 3D Human Tracheobronchial Epithelial Tissues: From Goblet Cell Hyperplasia to Squamous Metaplasia

Electronic cigarette (EC) aerosols are increasingly recognized for their disruptive effects on airway physiology, yet the temporal progression of epithelial remodeling remains poorly characterized. While squamous metaplasia, mucin hypersecretion, and ciliary dysfunction are hallmark features of smoking-related airway disease, analogous data for EC exposure are limited. To address this gap, we employed a 3D human tracheobronchial epithelial tissue (hTET) model derived from airway basal stem cells and exposed it daily to NJOY ACE "Classic Tobacco" aerosols (1 or 5 puffs) or clean air for 1, 2, or 3 weeks. Remodeling was assessed via immunolabeling and Western blot analysis. MUC5AC expression revealed a transient hypersecretory response, peaking at week 2 and declining by week 3. Multiparametric analysis demonstrated progressive squamous remodeling: early ciliary loss and involucrin upregulation emerged by week 1, with severity increasing in a puff-dependent manner. By week 2, tissues exhibited marked ciliary depletion, altered epithelial thickness, horizontal nuclear reorientation, and elevated involucrin. At week 3, both exposure groups developed a squamous metaplasia phenotype, characterized by involucrin-positive squamous cells replacing ciliated cells. Quantitative analysis confirmed sustained involucrin elevation, with the 1-puff group reaching levels comparable to the 5-puff group by week 3. These findings delineate a sequential pathological trajectory initiated by EC aerosols, progressing from transient goblet cell activation to squamous metaplasia. This human-relevant model underscores the potential for repeated low-level EC exposure to induce airway epithelial remodeling and pathology.

pharmacology and toxicology↗

bioRxiv2025

Unraveling the Toxicological Effects of Hydroxyacetone - A Reaction Product in Electronic Cigarette Aerosols

Hydroxyacetone has been detected at high concentrations (up to [~]12 mg/mL) in electronic cigarette (EC) aerosols, including those derived from products associated with adverse health effects. Given the limited understanding of its inhalation toxicology, we investigated hydroxyacetones impact on human airway epithelial cells. Acute exposures at the air-liquid interface (ALI) using 3D EpiAirway tissues--a surrogate for human tracheobronchial epithelium--were analyzed via proteomics. Differential expression analysis identified numerous affected proteins, with enrichment pointing to alterations in mitochondrial function and actin cytoskeletal disruption as major targets. Ingenuity Pathway Analysis (IPA) highlighted "Mitochondrial Dysfunction" and "NRF2-Mediated Oxidative Stress" among top toxicological categories, and "Nuclear Cytoskeletal Signaling" as a key canonical pathway. To validate and extend these findings, submerged cultures of BEAS-2B cells were exposed to hydroxyacetone (0.01-10 mg/mL) and assessed for mitochondrial activity, oxidative stress, and F-actin integrity. At 1 mg/mL, mitochondrial membrane potential and reactive oxygen species (ROS) increased, with elevated hydrogen peroxide detected in the culture medium. At 10 mg/mL, mitochondrial activity declined significantly, accompanied by cell rounding and apoptotic blebbing within 2 hours. F-actin destabilization occurred at 1, 3.33, and 10 mg/mL, with cytoplasmic and perinuclear filaments more affected than cortical actin. Findings from ALI and submerged models were concordant, supporting hydroxyacetone-induced mitochondrial stress, oxidative damage, and cytoskeletal disruption. These results suggest that hydroxyacetone concentrations found in EC aerosols may contribute to respiratory toxicity and warrant further investigation.

pharmacology and toxicology↗

bioRxiv2025

A Synthetic Coolant (WS-23) in Electronic Cigarettes Disrupts Normal Development of Human Embryonic Cells

Electronic cigarettes (ECs) often contain high concentrations of WS-23, a synthetic coolant. Our goal was to determine if WS-23 activates TRPM8 channels in human embryonic stem cells (hESCs), leading to abnormal embryonic development. Nanomolar concentrations of WS-23 triggered calcium influx in hESCs, as visualized using Fluo-8. Live cell imaging showed that 26 to 2600 nM of WS-23 inhibited hESC colony growth in a concentration dependent manner. Growth inhibition was caused by an increase in cell death and a reduction in cell division. Exposure to nM WS-23 inhibited mitochondrial reductases in the MTT assay, altered colony morphology, and induced formation of gaps between cells. The above processes were blocked by a TRPM8 channel antagonist. WS-23 at concentrations as low as 26 nM caused loss of OCT4 (a pluripotency marker) in hESCs and expression of SOX17 (an endoderm marker). These data show that WS-23 could reach an embryo during maternal vaping at concentrations sufficient to disrupt normal development. HighlightsO_LIWS-23 is a synthetic coolant frequently used in modern electronic cigarettes C_LIO_LINanomolar WS-23 adversely affected human epiblast and germ layer cells C_LIO_LIWS-23 caused loss of pluripotency and induced endoderm differentiation C_LIO_LIPregnant women should not vape electronic cigarettes with WS-23 C_LI

developmental biology↗

bioRxiv2025

SARS-CoV-2 Viral Pseudoparticles Preferentially Infect Ectoderm In Human Embryonic Tissues

Early stages in human development are difficult to study in pregnant women. We used a "disease-in-a-dish" model to investigate SARS-CoV-2 infection of human embryonic stem cells and the three germ layers. Ectoderm had a significantly higher infection than the other cell types. This was due to: (1) the use of two entry pathways by the ectoderm (fusion and endocytosis), (2) high levels of TMPRSS2 in the ectoderm, and (3) a much-reduced ectodermal glycocalyx, which facilitated viral attachment to the ACE2 receptor. Our findings provide strong evidence that cells in young postimplantation human embryos are susceptible to SARS-CoV-2 infection, which could be embryo lethal or teratogenic in surviving embryos. The high level of infection in ectoderm is a concern as its derivatives may also be affected by SARS-CoV-2. Future clinical work should investigate the functioning of the nervous system in infants born to mothers who had COVID-19 during pregnancy. HighlightsSARS-CoV-2 pseudoparticles infected human embryonic stem cells, endoderm, mesoderm and ectoderm Ectoderm was significantly more susceptible to infection than the other three cell types Factors accounting for increased susceptibility and tissue tropism were identified SARS-CoV-2 virus can adversely affect early stages of human development

cell biology↗

bioRxiv2024

Ultrasonic Cigarettes: Chemicals and Cytotoxicity are Similar to Heated-Coil Pod-Style Electronic Cigarettes

Our purpose was to test the hypothesis that ultrasonic cigarettes (u-cigarettes), which operate at relatively low temperatures, produce aerosols that are less harmful than heated-coil pod-style electronic cigarettes (e-cigarettes). The major chemicals in SURGE u-cigarette fluids and aerosols were quantified, their cytotoxicity and cellular effects were assessed, and a Margin of Exposure risk assessment was performed on chemicals in SURGE fluids. Four SURGE u-cigarette flavor variants ("Watermelon Ice," "Blueberry Ice," "Green Mint," and "Polar Mint") were evaluated. Flavor chemicals were quantified in fluids and aerosols using gas chromatography/mass spectrometry. Cytotoxicity and cell dynamics were assessed using the MTT assay, live-cell imaging, and fluorescent microscopy. WS-23 (a coolant) and total flavor chemical concentrations in SURGE were similar to e-cigarettes, while SURGE nicotine concentrations (13 - 19 mg/mL) were lower than many 4th generation e-cigarettes. Transfer efficiencies of dominant chemicals to aerosols in SURGE ranged from 44 - 100%. SURGE fluids and aerosols had four dominant flavor chemicals (> 1 mg/mL). Toxic aldehydes were usually higher in SURGE aerosols than in SURGE fluids. SURGE fluids and aerosols had aldehyde concentrations significantly higher than pod-style e-cigarettes. Chemical constituents, solvent ratios, and aldehydes varied among SURGE flavor variants. SURGE fluids and aerosols inhibited cell growth and mitochondrial reductases, produced attenuated and round cells, and depolymerized actin filaments, effects that depended on pod flavor, chemical constituents, and concentration. The MOEs for nicotine, WS-23, and propylene glycol were < 100 based on consumption of 1 - 2 SURGE cigarettes/day. Replacing the heating coil with a sonicator did not eliminate chemicals, including aldehydes, in aerosols or diminish toxicity in comparisons between SURGE and other pod products. The high concentrations of nicotine, WS-23, flavor chemicals, and aldehydes and the cytotoxicity of SURGE aerosols do not support the hypothesis that aerosols from u-cigarettes are less harmful than those from e-cigarettes.

pharmacology and toxicology↗

bioRxiv2023

Endocytosis Inhibitors Block SARS-CoV-2 Pseudoparticle Infection of Mink Lung Epithelium

Both spill over and spill back of SARS-CoV-2 virus have been reported on mink farms in Europe and the United States. Zoonosis is a public health concern as dangerous mutated forms of the virus could be introduced into the human population through spillback. The purpose of our study was to determine the SARS-CoV-2 entry mechanism using mink lung epithelial cell line (Mv1Lu) and to block entry with drug inhibitors. Mv1Lu cells were susceptible to SARS-CoV-2 viral pseudoparticle infection, validating them as a suitable disease model for COVID-19. Inhibitors of TMPRSS2 and of endocytosis, two pathways of viral entry, were tested to identify those that blocked infection. Dyngo4a, a small molecule endocytosis inhibitor, significantly reduced infection, while TMPRSS2 inhibitors had minimal impact, supporting the conclusion that the entry of the SARS-CoV-2 virus into Mv1Lu cells occurs primarily through endocytosis. The small molecule inhibitors that were effective in this study could potentially be used therapeutically to prevent SARS-CoV-2 infection in mink populations. This study will facilitate the development of therapeutics to prevent zoonotic transmission of SARS-CoV-2 variants to other animals, including humans.

cell biology↗

bioRxiv2022

Does Vaping Increase the Likelihood of SARS-CoV-2 Infection? Paradoxically Yes and No

Data on the relationship between electronic cigarettes (ECs) and SARS-CoV-2 infection are limited and contradictory. Evidence indicates that EC aerosols or nicotine increase ACE2, SARS-CoV-2 virus receptors, which increase virus binding and susceptibility. Our objectives were to determine if EC aerosols increased SARS-CoV-2 infection of human bronchial epithelial cells and to identify the causative chemical(s). A 3D organotypic model (EpiAirway) in conjunction with air liquid interface (ALI) exposure was used to test the effects of aerosols produced from JUUL "Virginia Tobacco" and BLU ECs, or individual chemicals (nicotine, propylene glycol, vegetable glycerin (PG/VG), and benzoic acid) on infection using SARS-CoV-2 pseudoparticles. Exposure of EpiAirway to JUUL aerosols increased ACE2, while BLU and lab-made EC aerosols containing nicotine increased ACE2 levels and TMPRSS2 activity, a spike protease that enables viral-cell fusion. Pseudoparticle infection of EpiAirway increased with aerosols produced from PG/VG, PG/VG plus nicotine, or BLU ECs. JUUL EC aerosols did not increase infection above controls. The baseline level of infection in JUUL treated aerosol groups was attributed to benzoic acid, which mitigated the enhanced infection caused by PG/VG or nicotine. The benzoic acid protection from enhanced infection continued at least 48 hours after exposure. TMPRSS2 activity was significantly correlated with e-liquid pH, which in turn was significantly correlated with infection, with lower pH blocking PG/VG and nicotine-induced-enhanced infection. While ACE2 levels increased in EpiAirway tissues exposed to EC aerosols, infection depended on the ingredients of the e-liquids. PG/VG and nicotine enhanced infection, an effect that was mitigated by benzoic acid.

cell biology↗

bioRxiv2022

New Insights into How JUUL Electronic Cigarette Aerosols and Aerosol Constituents Affect SARS-CoV-2 Infection of Human Bronchial Epithelial Cells

BackgroundThe relationship between the use of tobacco products and SARS-CoV-2 infection is poorly understood and controversial. Most studies have been done with tobacco cigarettes, while few have examined the effect of electronic cigarettes (ECs) on SARS-CoV-2 infection. We tested the hypothesis that EC fluids and aerosols with high concentrations of nicotine promote SARS-COV-2 infection by increasing viral entry into human respiratory epithelial cells. MethodsResponses of BEAS-2B cells to authentic JUUL aerosols or their individual constituents (propylene glycol (PG)/vegetable glycerin (VG) and nicotine) were compared using three exposure platforms: submerged culture, air-liquid-interface (ALI) exposure in a cloud chamber, and ALI exposure in a Cultex(R) system, which produces authentic heated EC aerosols. SARS-CoV-2 infection machinery was assessed using immunohistochemistry and Western blotting. Specifically, the levels of the SARS-CoV-2 receptor ACE2 (angiotensin converting enzyme 2) and a spike modifying enzyme, TMPRSS2 (transmembrane serine protease 2), were evaluated. Following each exposure, lentivirus pseudoparticles with spike protein and a green-fluorescent reporter were used to test viral penetration and the susceptibility of BEAS-2B cells to infection. ResultsNicotine, EC fluids, and authentic JUUL aerosols increased both ACE2 levels and TMPRSS2 activity, which in turn increased viral particle entry into cells. While most data were in good agreement across the three exposure platforms, cells were more responsive to treatments when exposed at the ALI in the Cultex system, even though the exposures were brief and intermittent. In the Cultex system, PG/VG, PG/VG/nicotine, and JUUL aerosols significantly increased infection above clean air controls. However, both the PG/VG and JUUL treatments were significantly lower than nicotine/PG/VG. PG/VG increased infection only in the Cultex(R) system, which produces heated aerosol. ConclusionOur data are consistent with the conclusion that authentic JUUL aerosols or their individual constituents (nicotine or PG/VG) increase SARS-CoV-2 infection. The strong effect produced by nicotine was modulated in authentic JUUL aerosols, demonstrating the importance of studying mixtures and aerosols from actual EC products. These data support the idea that vaping increases the likelihood of contracting COVID-19.

cell biology↗

bioRxiv2022

Digital data repository and automatic analysis framework for FDOPA PET neuroimaging

IntroductionFDOPA PET has been used extensively to image the human brain in many clinical disorders and has the potential to be used for patient stratification and individualized treatment. However, to reach its full and effective clinical translation, FDOPA PET requires both a robust data infrastructure and analytical protocol that are capable of ensuring high quality data and metadata, accurate biological quantification, and replicable results. In this study we evaluate a digital data repository and automated analytical framework for FDOPA PET neuroimaging that can produce an individualised quantification of dopamine synthesis capacity in the living human brain. MethodsThe imaging platform XNAT was used to store the Kings College London institutional brain FDOPA PET imaging archive, alongside individual demographics and clinical information. A fully automated analysis pipeline for imaging processing and data quantification was developed in Python and integrated in XNAT using the Docker technology. Reproducibility was assessed in test-retest datasets both in controls and patients with psychosis. The agreement between the automated analysis estimates and the results derived by the manual analysis were compared. Finally, using a sample of healthy controls (N=115), a sensitivity analysis was performed to explore the impact of experimental and demographic variables on the FDOPA PET measures. ResultsThe final data repository includes 892 FDOPA PET scans organized from 23 different studies, collected at five different imaging sites. After removing commercials studies, the infrastructure consisted of 792 FDOPA PET scans from 666 individuals (female 33.9%, healthy controls 29.1%) collected from four different imaging sites between 2004-2021. The automated analysis pipeline provided results that were in agreement with the results from the manual analysis, with a Pearsons correlation that ranged from 0.64 to 0.99 for Kicer, and from 0.79 to 1.00 for SUVR. The mean absolute difference between the two pipelines ranges from 3.4% to 9.4% for Kicer, and from 2.5% to 12.4% for SUVR. Moreover, we found good reproducibility of the data analysis by the automated pipeline (in the whole striatum for the Kicer: ICC for the controls = 0.71, ICC for the psychotic patients = 0.88). From the demographic and experimental variables assessed, gender was found to most influence striatal dopamine synthesis capacity (F = 10.7, p <0.001), with women showing greater dopamine synthesis capacity than men, while the effects of weight, age, injected radioactivity, and scanner, varied by brain region and parameter of interest. ConclusionsCombining information from different neuroimaging studies has allowed us to test comprehensively the automated pipeline for quantification of dopamine synthesis capacity using FDOPA PET data and to validate its replicability and reproducibility performances on a large sample size. This validation process is a necessary methodological step for the development of the clinical application of FDOPA PET as precision medicine biomarker. The proposed infrastructure is generalisable behind the FDOPA radiotracer.

bioengineering↗

bioRxiv2020

Tracking the Movement of Electronic Cigarette Flavor Chemicals and Nicotine from Refill Fluids to Aerosol, Lungs and Exhale

Electronic cigarettes (ECs) have been linked to lung diseases, including COVID-19, with little understanding of exposure, retention, and exhalation of EC aerosol chemicals. Here, flavor chemicals and nicotine were quantified in two refill fluids, their transfer efficiency to EC aerosols was determined, exhalation by human participants was measured, and chemical retention was modeled. Nicotine transferred well to aerosols irrespective of topography; however, transfer efficiencies of flavor chemicals depended on the chemical, puff volume, puff duration, pump head, and EC power. Participants could be classified as "mouth inhalers" or "lung inhalers" based on their retention and exhale of flavor chemicals and nicotine. Only mouth inhalers exhaled sufficient concentrations of flavor chemicals and nicotine to contribute to chemical deposition on environmental surfaces. These data help distinguish two types of EC users, add to our knowledge of chemical exposure during vaping, and provide information useful in treating EC-related diseases and regulating EC use.

pharmacology and toxicology↗

bioRxiv2020

Menthol in Electronic Cigarettes: A Contributor to Respiratory Disease?

Menthol is widely used in tobacco products. This study compared the effects of menthol on human bronchial epithelium using submerged cultures, a VITROCELL(R) cloud chamber that provides air liquid interface (ALI) exposure without solvents or heating, and a Cultex ALI system that delivers aerosol equivalent to that inhaled during vaping. In submerged culture, menthol significantly increased calcium influx and mitochondrial reactive oxygen species (ROS) via the TRPM8 receptor, responses that were inhibited by a TRPM8 antagonist. VITROCELL(R) cloud chamber exposure of BEAS-2B monolayers increased mitochondrial protein oxidation, expression of the antioxidant enzyme SOD2, activation of NF-{kappa}B, and secretion of inflammatory cytokines (IL-6 and IL-8). Proteomics data collected following ALI exposure of 3D EpiAirway tissue in the Cultex showed upregulation of NRF-2-mediated oxidative stress, oxidative phosphorylation, and IL-8 signaling. Across the three platforms, menthol adversely effected human bronchial epithelium in a manner that could lead to respiratory disease. O_FIG O_LINKSMALLFIG WIDTH=115 HEIGHT=200 SRC="FIGDIR/small/988006v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@b86c96org.highwire.dtl.DTLVardef@1e12bd2org.highwire.dtl.DTLVardef@4008corg.highwire.dtl.DTLVardef@c01cad_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract. Mechanism of action of menthol on human bronchial epithelium.Three in vitro platforms were used to study the effect of menthol on bronchial epithelium. In submerged culture (using BEAS-2B cells), menthol produced rapid calcium influx followed by an increase in oxidative stress and inflammatory cytokines. ALI exposure of BEAS-2B cells to unheated menthol in a cloud chamber caused activation of an inflammatory transcription factor (NF-{kappa}B) and oxidative stress. Proteomics analysis of human EpiAirway tissues exposed at the ALI to heated menthol EC aerosols identified changes in the expression of proteins involved in oxidative stress and in an inflammatory response. C_FIG

cell biology↗

bioRxiv2018

Toxicity of JUUL Fluids and Aerosols Correlates Strongly with Nicotine and Some Flavor Chemical Concentrations

While JUUL electronic cigarettes (ECs) have captured the majority of the EC market with a large fraction of their sales going to adolescents, little is known about their cytotoxicity and potential effects on health. The purpose of this study was to determine flavor chemical and nicotine concentrations in the eight currently marketed pre-filled JUUL EC cartridges (\"pods\") and to evaluate the cytotoxicity of the different variants (e.g., \"Cool Mint\" and \"Creme Brulee\") using in vitro assays. Nicotine and flavor chemicals were analyzed using gas chromatography/mass spectrometry in pod fluid before and after vaping and in the corresponding aerosols. 59 flavor chemicals were identified in JUUL pod fluids, and three were >1 mg/mL. Duplicate pods were similar in flavor chemical composition and concentration. Nicotine concentrations (average 60.9 mg/mL) were significantly higher than any EC products we have analyzed previously. Transfer efficiency of individual flavor chemicals that were >1mg/mL and nicotine from the pod fluid into aerosols was generally 35 - 80%. All pod fluids were cytotoxic at a 1:10 dilution (10%) in the MTT and neutral red uptake assays when tested with BEAS-2B lung epithelial cells. Most aerosols were cytotoxic in these assays at concentrations >1%. The cytotoxicity of aerosols was highly correlated with nicotine and ethyl maltol concentrations and moderately to weakly correlated with total flavor chemical concentration and menthol concentration. Our study demonstrates that: (1) some JUUL flavor pods have high concentrations of flavor chemicals that may make them attractive to youth, and (2) the concentrations of nicotine and some flavor chemicals (e.g. ethyl maltol) are high enough to be cytotoxic in acute in vitro assays, emphasizing the need to determine if JUUL products will lead to adverse health effects with chronic use.

pharmacology and toxicology↗