Sensing with Thermally Reduced Graphene Oxide under Repeated Large Multi-Directional Strain.

This paper presents a recent investigation into the electromechanical behavior of thermally reduced graphene oxide (rGO) as a strain sensor undergoing repeated large mechanical strains up to 20.72%, with electrical signal output measurement in multiple directions relative to the applied strain. Strain is one the most basic and most common stimuli sensed. rGO can be synthesized from abundant materials, can survive exposure to large strains (up to 20.72%), can be synthesized directly on structures with relative ease, and provides high sensitivity, with gauge factors up to 200 regularly reported. In this investigation, a suspension of graphene oxide flakes was deposited onto Polydimethylsiloxane (PDMS) substrates and thermally reduced to create macroscopic rGO-strain sensors. Electrical resistance parallel to the direction of applied tension (x^) demonstrated linear behavior (similar to the piezoresistive behavior of solid materials under strain) up to strains around 7.5%, beyond which nonlinear resistive behavior (similar to percolative electrical behavior) was observed. Cyclic tensile testing results suggested that some residual micro-cracks remained in place after relaxation from the first cycle of tensile loading. A linear fit across the range of strains investigated produced a gauge factor of 91.50(Ω/Ω)/(m/m), though it was observed that the behavior at high strains was clearly nonlinear. Hysteresis testing showed high consistency in the electromechanical response of the sensor between loading and unloading within cycles as well as increased consistency in the pattern of the response between different cycles starting from cycle 2.

Enhancing clinical and public health interpretation of accelerometer-assessed physical activity with age-referenced values based on UK Biobank data.

BACKGROUND: Higher accelerometer-assessed volume and intensity of physical activity (PA) have been associated with a longer life expectancy but can be difficult to translate into recommended doses of PA. We aimed to: (a) improve interpretability by producing UK Biobank age-referenced centiles for PA volume and intensity; (b) inform public-health messaging by examining how adding recommended quantities of moderate and vigorous PA affect PA volume and intensity. METHODS: 92,480 UK Biobank participants aged 43-80 years with wrist-worn accelerometer data were included. Average acceleration and intensity gradient were derived as proxies for PA volume and intensity. We generated sex-specific centile curves using Generalized Additive Models for Location Scale and Shape (GAMLSS) and modeled the effect of adding moderate (walking) or vigorous (running) activity on the combined change in the volume and intensity centiles (change in PA profile). RESULTS: In men, volume was lower as age increased while intensity was lower after age 55; in women, both volume and intensity were lower as age increased. Adding 150 min of moderate PA weekly (5 × 30 min walking) increased the PA profile by 4 percentage points. Defining moderate PA as brisk walking approximately doubled the increase (9 percentage points) while 75 min of vigorous PA weekly (5 × 15 min running) trebled the increase (13 percentage points). CONCLUSION: These UK Biobank reference centiles provide a benchmark for interpretation of accelerometer data. Application of our translational methods demonstrate that meeting PA guidelines through shorter duration vigorous activity is more beneficial to the PA profile (volume and intensity) than longer duration moderate activity.

Examining public preferences for wood smoke mitigation policies in the sub-Arctic.

Outdoor air pollution is a significant problem worldwide. Policies developed to mitigate air pollution require support from local residents to be successful. While some research has examined various social and psychological metrics associated with support for some types of pollution mitigation, less is known about what variables are critical in resident support for different types of policies that help mitigate air pollution associated with woodsmoke. This research examined the extent that perceived health and economic risks, perceived uncertainties in measuring air quality and estimating risks, trust in government, and affect relate to support for three different types of outdoor wood smoke mitigation policies in Alaska. Using a multiple regression analysis of data obtained from a mail-based survey (n = 442), we characterized local affective associations with wood burning, economic concerns and health risks around heat options, perceived uncertainties, and levels of trust in government. The research identified several social and psychological variables that were important in understanding support for air pollution policies associated with wood smoke. Significantly, we found that perceived economic risk of not taking actions to mitigate outdoor air pollution from wood smoke was related to support for all three policy options. Trust in local government was positively correlated to support for education and regulatory policies, and perceived uncertainty was inversely related to support for regulations. The research also confirmed other known findings with respect to variables associated with support for air pollution regulation policies including perceived health risks and affect.

Evaluation of rifle cartridge and shot placement for euthanizing feral swine (Sus scrofa) in traps.

Feral swine are a highly destructive invasive species around the globe. Wildlife managers commonly trap and euthanize feral swine with firearms to reduce their adverse impacts. The utility of euthanizing domestic swine with firearms has been considered when emergency situations arise such as in the event of a foreign animal disease outbreak in domestic swine. Similarly, the rapid depopulation of domestic swine facilities became necessary when the COVID-19 pandemic disrupted pork production in 2020. Evaluation of the effects of caliber, cartridge, size of feral swine, and shot placement on effectiveness and safety of the method is needed. We collected data from feral swine euthanized in traps on how those variables influenced the effectiveness in time to death and number of shots required and safety risks based on the occurrence of bullet pass-through (i.e., bullet exiting the pig). We tested three cartridges of two calibers (.22 long rifle, .22 Winchester magnum rimfire, and .308 Winchester) delivered from a rifle with three shot placements targeting the brain. From 570 euthanization events, we calculated an average time to death of 100.06 (SD = 29.24) seconds, with larger feral swine taking slightly longer. Most feral swine (73%) were euthanized with a single shot but averaged 1.28 (SD = 0.48) shots overall. Safety risks from pass-through shots were more common when using the .308 Winchester cartridge, and when rear and side shot placements were used. Overall, we recommend a .22 long rifle cartridge and frontal shot placement as an effective and safe option for euthanizing feral swine in traps, and likely for domestic swine of similar size and shot distances.

Comparing efficiencies of population control methods for responding to introductions of transboundary animal diseases in wild pigs.

Introductions of transboundary animal diseases (TADs) into free-ranging wildlife can be difficult to control and devastating for domestic livestock trade. Combating a new TAD introduction in wildlife with an emergency response requires quickly limiting spread of the disease by intensely removing wild animals within a contiguous area. In the case of African swine fever virus (ASFv) in wild pigs (Sus scrofa), which has been spreading in many regions of the world, there is little information on the time- and cost-efficiency of methods for intensively and consistently culling wild pigs and recovering carcasses in an emergency response scenario. We compared the efficiencies of aerial operations, trapping, experimental toxic baiting, and ground shooting in northcentral Texas, USA during two months in 2023. Culling and recovering carcasses of wild pigs averaged a rate of 0.15 wild pigs/person hour and cost an average of $233.04/wild pig ($USD 2023) across all four methods. Aerial operations required the greatest initial investment but subsequently was the most time- and cost-efficient, costing an average of $7266 to reduce the population by a standard measure of 10 %, including recovering carcasses. Aerial operations required a ground crew of ∼7 people/helicopter to recover carcasses. Costs for reducing the population of wild pigs using trapping were similar, although took 13.5 times longer to accomplish. In cases where carcass recovery and disposal are needed (e.g., response to ASFv), a benefit of trapping was immediate carcass recovery. Toxic baiting was less efficient because both culling and carcass recovery required substantial time. We culled very few wild pigs with ground shooting in this landscape. Our results provide insight on the efficiencies of each removal method. Strategically combining removal methods may increase overall efficiency. Overall, our findings inform the preparation of resources, personnel needs, and deployment readiness for TAD responses involving wild pigs.

The LEAP2 response to cancer-related anorexia-cachexia syndrome in male mice and patients.

The hormone ghrelin serves a protective role in cancer-related anorexia-cachexia syndrome (CACS) - a condition in which plasma levels of ghrelin rise, its administration lessens CACS severity, and experimentally-reduced signaling by its receptor (GHSR) worsens fat loss and anorexia and accelerates death. Yet, actions for the related hormone liver-expressed antimicrobial peptide-2 (LEAP2), which is an endogenous GHSR antagonist, are unexplored in CACS. Here, we found that plasma LEAP2 and LEAP2/ghrelin ratio were lower in Lewis Lung Carcinoma (LLC) and RM-9 prostate cancer CACS mouse models. Ghrelin deletion exaggerated losses of tumor-free body weight and fat mass, reduced food intake, reduced soleus muscle weight, and/or lowered grip strength in LLC or RM-9 tumor-bearing mice. LEAP2 deletion lessened reductions in tumor-free body weight and fat mass and increased food intake in LLC or RM-9 tumor-bearing mice. In a 55-subject cohort of patients with CACS or weight-stable cancer, the plasma LEAP2/total ghrelin ratio was negatively correlated with 6-month weight change preceding blood collection. These data demonstrate that ghrelin deletion exacerbates CACS in the LLC and RM-9 tumor-bearing mouse models while contrastingly, LEAP2 deletion reduces measures of CACS in these tumor-bearing mouse models. Further, they suggest that lower plasma LEAP2/ghrelin ratio protects against worsened CACS.

Mapping the immunopeptidome of seven SARS-CoV-2 antigens across common HLA haplotypes.

Most COVID-19 vaccines elicit immunity against the SARS-CoV-2 Spike protein. However, Spike protein mutations in emerging strains and immune evasion by the SARS-CoV-2 virus demonstrates the need to develop more broadly targeting vaccines. To facilitate this, we use mass spectrometry to identify immunopeptides derived from seven relatively conserved structural and non-structural SARS-CoV-2 proteins (N, E, Nsp1/4/5/8/9). We use two different B-lymphoblastoid cell lines to map Human Leukocyte Antigen (HLA) class I and class II immunopeptidomes covering some of the prevalent HLA types across the global human population. We employ DNA plasmid transfection and direct antigen delivery approaches to sample different antigens and find 248 unique HLA class I and HLA class II bound peptides with 71 derived from N, 12 from E, 28 from Nsp1, 19 from Nsp4, 73 from Nsp8 and 45 peptides derived from Nsp9. Over half of the viral peptides are unpublished. T cell reactivity tested against 56 of the detected peptides shows CD8+ and CD4+ T cell responses against several peptides from the N, E, and Nsp9 proteins. Results from this study will aid the development of next-generation COVID vaccines targeting epitopes from across a number of SARS-CoV-2 proteins.

Role of secondary interactions in a series of 2:1 halogen-bonded cocrystals formed between 4-(dimethylamino)pyridine and ditopic halogen-bond donors.

The structures of a series of 2:1 cocrystals formed between 4-(dimethylamino)pyridine and each of 1,2,4,5-tetrachloro-3,6-diiodobenzene, 2C7H10N2·C6Cl4I2, 1,2,4,5-tetrabromo-3,6-diiodobenzene, 2C7H10N2·C6Br4I2, 1-bromo-4-iodo-2,3,5,6-tetrafluorobenzene, 2C7H10N2·C6BrF4I, and 1,2-dibromo-4,5-difluoro-3,6-diiodobenzene, 2C7H10N2·C6Br2F2I2, are reported. In all five structures, the core halogen-bonded 2:1 trimolecular units have geometrically similar parameters, with the central halogen-bond donor flanked by two pyridine halogen-bond acceptors twisted with respect to the central halogen-bond donor at angles ranging from 76 to 86°. The I...N halogen-bond separations are all short, ranging from 73.3 to 76.7% of the sum of the van der Waals radii, while the C-I...N bond angles are essentially linear. The Br...N halogen-bond separation in the cocrystal formed with 1-bromo-4-iodo-2,3,5,6-tetrafluorobenzene is 80.4% of the sum of the van der Waals radii. Subtle differences in the crystal packings are attributed to the role of secondary C-H...π and weak π-type interactions with chloro and bromo substituents. The cocrystals 2C7H10N2·C6Cl4I2 and 2C7H10N2·C6Br4I2 are isomorphous.

Evaluation of nikkomycin Z with frequent oral administration in an experimental model of central nervous system coccidioidomycosis.

We evaluated the in vivo activity of nikkomycin Z against central nervous system coccidioidomycosis. Mice were inoculated intracranially with arthroconidia of Coccidoides immitis, and treatment with nikkomycin Z (50, 100, or 300 mg/kg orally TID) or fluconazole (25 mg/kg orally BID) began 2 days later. Each dose of nikkomycin Z and fluconazole significantly improved survival and reduced brain fungal burden compared with vehicle control. Further studies of nikkomycin Z against coccidioidomycosis are warranted. IMPORTANCE: Coccidioides species are endemic fungi that are capable of causing disease in patients with various comorbidities, as well as in otherwise healthy individuals. Treatment options for coccidioidomycosis are suboptimal, as azole antifungals may be limited by drug interactions and adverse effects due to interactions with enzymes found in humans and other mammals. Nikkomycin Z is an investigational agent that works against a target specific to the fungal cell wall (chitin), which is not present in the cells of humans or other mammals. In this study, we show that frequent oral administration of nikkomycin Z is effective in an experimental model of central nervous system coccidioidomycosis. Further studies of nikkomycin Z against coccidioidomycosis may be warranted.

Factors Associated With Infection in Patients With Combined Pelvic Ring and Bladder Injuries.

OBJECTIVES: To identify the infection rate in patients with combined pelvic ring and bladder injuries. Secondary aims included identifying treatment and injury factors associated with infection. DESIGN: Retrospective review. SETTING: Single Level I Tertiary Academic Center. PATIENTS SELECTION CRITERIA: All patients over a 12-year period with combined pelvic ring and bladder injuries were evaluated. Exclusion criteria were nonoperative management of the pelvic ring, isolated posterior fixation, and follow-up <90 days. OUTCOME MEASURE AND COMPARISONS: Primary outcome measured was deep infection of the anterior pelvis requiring surgical irrigation and debridement. RESULTS: In total, 106 patients with anterior stabilization of the pelvis in the setting of a bladder injury were included. Seven patients (6.6%) developed a deep infection and required surgical debridement within 90 days. Patients undergoing open reduction and internal fixation with plating of the anterior pelvis and acute concomitant bladder repair had an infection rate of 2.2% (1/43). Patients undergoing closed reduction and anterior fixation with either external fixation or percutaneous rami screw after bladder repair had an infection rate of 17.6% (3/17). There was a higher infection rate among patients with combined intraperitoneal (IP) and extraperitoneal (EP) bladder injuries (23%) when compared with those with isolated EP (3.8%) or IP (9.1%) bladder injuries (P = 0.029). CONCLUSIONS: Acute open reduction and internal fixation of the anterior pelvis in patients with combined pelvic ring and bladder injuries has a low infection rate. Patients with combined IP and EP bladder injuries are at increased risk of infection compared with those with isolated IP and EP injuries. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

α-Mannosylated HLA-II glycopeptide antigens dominate the immunopeptidome of immortalised cells and tumour tissues.

Immunopeptides are cell surface-located protein fragments that aid our immune system to recognise and respond to pathogenic insult and malignant transformation. In this two-part communication, we firstly summarise and reflect on our recent discovery documenting that MHC-II-bound immunopeptides from immortalised cell lines prevalently carry N-glycans that differ from the cellular glycoproteome (Goodson, Front Immunol, 2023). These findings are important as immunopeptide glycosylation remains poorly understood in immunosurveillance. The study also opened up new technical and biological questions that we address in the second part of this communication. Our study highlighted that the performance of the search engines used to detect glycosylated immunopeptides from LC-MS/MS data remains untested and, importantly, that little biochemical in vivo evidence is available to document the nature of glycopeptide antigens in tumour tissues. To this end, we compared the N-glycosylated MHC-II-bound immunopeptides that were reported from tumour tissues of 14 meningioma patients in the MSFragger-HLA-Glyco database (Bedran, Nat Commun, 2023) to those we identified with the commercial Byonic software. Encouragingly, the search engines produced similar outputs supporting that N-glycosylated MHC-II-bound immunopeptides are prevalent in meningioma tumour tissues. Consistent also with in vitro findings, the tissue-derived MHC-II-bound immunopeptides were found to predominantly carry hyper-processed (paucimannosidic- and chitobiose core-type) and hypo-processed (oligomannosidic-type) N-glycans that varied in prevalence and distribution between patients. Taken together, evidence is emerging suggesting that α-mannosidic glycoepitopes abundantly decorate MHC-II-bound immunopeptides presented in both immortalised cells and tumour tissues warranting further research into their functional roles in immunosurveillance.

An enterococcal phage protein inhibits type IV restriction enzymes involved in antiphage defense.

The prevalence of multidrug resistant (MDR) bacterial infections continues to rise as the development of antibiotics needed to combat these infections remains stagnant. MDR enterococci are a major contributor to this crisis. A potential therapeutic approach for combating MDR enterococci is bacteriophage (phage) therapy, which uses lytic viruses to infect and kill pathogenic bacteria. While phages that lyse some strains of MDR enterococci have been identified, other strains display high levels of resistance and the mechanisms underlying this resistance are poorly defined. Here, we use a CRISPR interference (CRISPRi) screen to identify a genetic locus found on a mobilizable plasmid from Enterococcus faecalis involved in phage resistance. This locus encodes a putative serine recombinase followed by a Type IV restriction enzyme (TIV-RE) that we show restricts the replication of phage phi47 in vancomycin-resistant E. faecalis. We further find that phi47 evolves to overcome restriction by acquiring a missense mutation in a TIV-RE inhibitor protein. We show that this inhibitor, termed type IV restriction inhibiting factor A (tifA), binds and inactivates diverse TIV-REs. Overall, our findings advance our understanding of phage defense in drug-resistant E. faecalis and provide mechanistic insight into how phages evolve to overcome antiphage defense systems.

How Do Financial Obstacles Affect Decision-Making Among Potential Living Organ Donors?

Introduction: Living donation increases the organ supply, but associated non-medical expenses can disincentivize donation. Programs aimed at increasing living donation need to better understand how financial obstacles, including lost wages, impact the decision to pursue donation. Methods/Approach: Forty-eight interviews were conducted and analyzed using a grounded theory approach. Findings: Three key themes were identified that influenced decision-making: emotional attachment, temporal flexibility, and job security. These themes emerged when dividing interview participants into 3 groups: close relationship donors, broader network donors, and non-directed donors, representing donation to a family member or friend, a specific person they do not know well or at all, or a non-specified individual, respectively. Most close relationship donors wanted to donate regardless of personal financial cost, based on emotional attachment to the recipient. Wage reimbursement did not typically affect their decision-making but could reduce stress. Since non-directed donors did not donate to a specific individual, they could wait to achieve financial stability before donating, if needed. While wage reimbursement might create more proximate stability, non-directed donors had the flexibility to postpone donations until they could independently achieve financial stability. Lacking emotional attachment and temporal flexibility, broader network donors were particularly active decision-makers and most influenced by wage reimbursement. Across all groups, donors with job security were more resolute about donating. Conclusion: The findings underscore the importance of lost wage reimbursement to facilitate donation and reduce stress, and policies to protect donor job security.

The role of microglia in neuronal and cognitive function during high altitude acclimatization.

Due to their interactions with the neurovasculature, microglia are implicated in maladaptive responses to hypobaric hypoxia at high altitude (HA). To explore these interactions at HA, pharmacological depletion of microglia with the colony-stimulating factor-1 receptor inhibitor, PLX5622, was employed in male C57BL/6J mice maintained at HA or sea level (SL) for 3-weeks, followed by assessment of ex-vivo hippocampal long-term potentiation (LTP), fear memory recall and microglial dynamics/physiology. Our findings revealed that microglia depletion decreased LTP and reduced glucose levels by 25% at SL but did not affect fear memory recall. At HA, the absence of microglia did not significantly alter HA associated deficits in fear memory or HA mediated decreases in peripheral glucose levels. In regard to microglial dynamics in the cortex, HA enhanced microglial surveillance activity, ablation of microglia resulted in increased chemotactic responses and decreased microglia tip proliferation during ball formation. In contrast, vessel ablation increased cortical microglia tip path tortuosity. In the hippocampus, changes in microglial dynamics were only observed in response to vessel ablation following HA. As the hippocampus is critical for learning and memory, poor hippocampal microglial context-dependent adaptation may be responsible for some of the enduring neurological deficits associated with HA.

SMN1 c.5C>G (p.Ala2Gly) missense variant, a challenging molecular SMA diagnosis associated with mild disease, preserves SMN nuclear gems in patient-specific fibroblasts.

Introduction: Spinal muscular atrophy (SMA) is caused by homozygous loss of the SMN1 gene with SMN2 gene copy number correlating with disease severity. Rarely SMA is caused by a deletion on one allele and a pathogenic variant on the other. The pathogenic missense variant c.5C>G (p.Ala2Gly) correlates with a mild disease phenotype that does not correlate with SMN2 copy number. In a mouse model the c.5C>G transgene produces SMN that is thought to form partially functional SMN complexes, but levels in humans have not yet been investigated. Methods: We identified two patients with mild SMA caused by a heterozygous deletion of SMN1 and the heterozygous variant, c.5C>G. Molecular findings were confirmed with deletion/duplication analysis and Sanger sequencing. Skin fibroblasts were collected and cultured, and SMN expression was analyzed using immunofluorescence. Results: Two patients with slowly progressing mild weakness were confirmed to have heterozygous pathogenic missense variant c.5C>G and a heterozygous deletion of SMN1. Their clinical presentation revealed much milder disease progression than patients with matched SMN2 copy number. Analysis of the patients' fibroblasts revealed much higher numbers of SMN nuclear complexes than a patient with a homozygous SMN1 deletion and matched SMN2 copy number. Conclusions: These case reports reinforce that the rare c.5C>G variant causes mild disease. Furthermore, the analysis of SMA nuclear gems in patient samples supports the theory that the p.Ala2Gly SMN can form partially functional SMN complexes that may carry out essential cellular functions and result in mild disease.

Late anastomotic perforation of the ileum 3 years after intestinal resection.

Late perforation of the ileum is a rare and potentially life-threatening complication following intestinal resection. We present a unique case of a woman in her 60s with a history of appendiceal carcinoid tumour, who underwent a right hemicolectomy. Positron emission tomography and surveillance CTs showed normal surgical changes and no recurrent malignancy. Three years postoperatively, she presented with severe abdominal pain. CT revealed a perforation along the ileal wall of the ileocolonic anastomosis. She underwent emergent resection and repeat ileocolonic anastomosis. We conclude that the patient had subclinical ischaemia of the anastomosis, which eventually progressed to perforation 3 years later. We discuss a literature review on late small intestinal anastomotic perforations and their associated risk factors. Our case and literature review emphasise the importance of considering delayed anastomotic leak in postoperative patients with a history of intestinal cancer, inflammatory bowel disease, Roux-en-Y enteroenterostomy or side-to-side anastomosis.

Living Donor Decision-Making and the Complex Interplay of Finances and Other Motivators, Barriers, and Facilitators.

INTRODUCTION: The decision to become a living donor requires consideration of a complex, interactive array of factors that could be targeted for clinical, policy, and educational interventions. Our objective was to assess how financial barriers interact with motivators, other barriers, and facilitators during this process. METHODS: Data were obtained from a public survey assessing motivators, barriers, and facilitators of living donation. We used multivariable logistic regression and consensus k-means clustering to assess interactions between financial concerns and other considerations in the decision-making process. RESULTS: Among 1592 respondents, the average age was 43; 74% were female and 14% and 6% identified as Hispanic and Black, respectively. Among employed respondents (72%), 40% indicated that they would not be able to donate without lost wage reimbursement. Stronger agreement with worries about expenses and dependent care challenges was associated with not being able to donate without lost wage reimbursement (OR = 1.2, 95% CI = 1.0-1.3; OR = 1.2, 95% CI = 1.1-1.3, respectively). Four respondent clusters were identified. Cluster 1 had strong motivators and facilitators with minimal barriers. Cluster 2 had barriers related to health concerns, nervousness, and dependent care. Clusters 3 and 4 had financial barriers. Cluster 3 also had anxiety related to surgery and dependent care. CONCLUSIONS: Financial barriers interact primarily with health and dependent care concerns when considering living organ donation. Targeted interventions to reduce financial barriers and improve provider communication regarding donation-related risks are needed.

A tandem activity-based sensing and labeling strategy reveals antioxidant response element regulation of labile iron pools.

Iron is an essential element for life owing to its ability to participate in a diverse array of oxidation-reduction reactions. However, misregulation of iron-dependent redox cycling can also produce oxidative stress, contributing to cell growth, proliferation, and death pathways underlying aging, cancer, neurodegeneration, and metabolic diseases. Fluorescent probes that selectively monitor loosely bound Fe(II) ions, termed the labile iron pool, are potentially powerful tools for studies of this metal nutrient; however, the dynamic spatiotemporal nature and potent fluorescence quenching capacity of these bioavailable metal stores pose challenges for their detection. Here, we report a tandem activity-based sensing and labeling strategy that enables imaging of labile iron pools in live cells through enhancement in cellular retention. Iron green-1 fluoromethyl (IG1-FM) reacts selectively with Fe(II) using an endoperoxide trigger to release a quinone methide dye for subsequent attachment to proximal biological nucleophiles, providing a permanent fluorescent stain at sites of elevated labile iron. IG1-FM imaging reveals that degradation of the major iron storage protein ferritin through ferritinophagy expands the labile iron pool, while activation of nuclear factor-erythroid 2-related factor 2 (NRF2) antioxidant response elements (AREs) depletes it. We further show that lung cancer cells with heightened NRF2 activation, and thus lower basal labile iron, have reduced viability when treated with an iron chelator. By connecting labile iron pools and NRF2-ARE activity to a druggable metal-dependent vulnerability in cancer, this work provides a starting point for broader investigations into the roles of transition metal and antioxidant signaling pathways in health and disease.

Glutathione synthesis in the mouse liver supports lipid abundance through NRF2 repression.

Cells rely on antioxidants to survive. The most abundant antioxidant is glutathione (GSH). The synthesis of GSH is non-redundantly controlled by the glutamate-cysteine ligase catalytic subunit (GCLC). GSH imbalance is implicated in many diseases, but the requirement for GSH in adult tissues is unclear. To interrogate this, we have developed a series of in vivo models to induce Gclc deletion in adult animals. We find that GSH is essential to lipid abundance in vivo. GSH levels are highest in liver tissue, which is also a hub for lipid production. While the loss of GSH does not cause liver failure, it decreases lipogenic enzyme expression, circulating triglyceride levels, and fat stores. Mechanistically, we find that GSH promotes lipid abundance by repressing NRF2, a transcription factor induced by oxidative stress. These studies identify GSH as a fulcrum in the liver's balance of redox buffering and triglyceride production.