Divergent Genetic Regulation of Nitric Oxide Production between C57BL/6J and Wild-Derived PWD/PhJ Mice Controls Postactivation Mitochondrial Metabolism, Cell Survival, and Bacterial Resistance in Dendritic Cells.

Dendritic cell (DC) activation is characterized by sustained commitment to glycolysis that is a requirement for survival in DC subsets that express inducible NO synthase (Nos2) due to NO-mediated inhibition of mitochondrial respiration. This phenomenon primarily has been studied in DCs from the classic laboratory inbred mouse strain C57BL/6J (B6) mice, where DCs experience a loss of mitochondrial function due to NO accumulation. To assess the conservation of NO-driven metabolic regulation in DCs, we compared B6 mice to the wild-derived genetically divergent PWD/PhJ (PWD) strain. We show preserved mitochondrial respiration and enhanced postactivation survival due to attenuated NO production in LPS-stimulated PWD DCs phenocopying human monocyte-derived DCs. To genetically map this phenotype, we used a congenic mouse strain (B6.PWD-Chr11.2) that carries a PWD-derived portion of chromosome 11, including Nos2, on a B6 background. B6.PWD-Chr11.2 DCs show preserved mitochondrial function and produce lower NO levels than B6 DCs. We demonstrate that activated B6.PWD-Chr11.2 DCs maintain mitochondrial respiration and TCA cycle carbon flux, compared with B6 DCs. However, reduced NO production by the PWD Nos2 allele results in impaired cellular control of Listeria monocytogenes replication. These studies establish a natural genetic model for restrained endogenous NO production to investigate the contribution of NO in regulating the interplay between DC metabolism and immune function. These findings suggest that reported differences between human and murine DCs may be an artifact of the limited genetic diversity of the mouse models used, underscoring the need for mouse genetic diversity in immunology research.

Trends in management and outcomes of pulmonary embolism with a multidisciplinary response team.

Multidisciplinary pulmonary embolism (PE) response teams have garnered widespread adoption given the complexities of managing acute PE and provide a platform for assessment of trends in therapy and outcomes. We describe temporal trends in PE management and outcomes following the deployment of such a team. All consecutive patients managed by our multidisciplinary PE response team activated by the Emergency Department were included over a 5-year calendar period. We examined temporal trends in management and rates of a composite primary endpoint (all-cause-death, major bleeding, recurrent venous thromboembolism, and readmission) at 30 days and 6 months. We assessed 425 patients between 2015 and 2019. We observed an increase in PE acuity and use of systemic thrombolysis. The primary endpoint at 30 days decreased from 16.3% in 2015 to 7.1% in 2019 (adjusted rate ratio per period, 0.63; 95%CI, 0.47-0.84), driven by a decrease in the adjusted rate of major bleeding. Among 406 patients with complete follow-up, the adjusted rate ratio per year for the primary outcome at 6 months was 0.37 (95%CI, 0.19-0.71), driven by a decrease in all-cause mortality. We observed evidence of temporal changes in clinical presentation, therapeutic strategies, and outcomes for acute PE, in parallel to, but not necessarily because of, the implementation of a multidisciplinary response team. Over time, major bleeding, mortality and readmission rates decreased, despite an increase in PE risk category.

MYBPC3 truncation mutations enhance actomyosin contractile mechanics in human hypertrophic cardiomyopathy.

RATIONALE: Truncation mutations in the MYBPC3 gene, encoding for cardiac myosin-binding protein C (MyBP-C), are the leading cause of hypertrophic cardiomyopathy (HCM). Whole heart, fiber and molecular studies demonstrate that MyBP-C is a potent modulator of cardiac contractility, but how these mutations contribute to HCM is unresolved. OBJECTIVES: To readdress whether MYBPC3 truncation mutations result in loss of MyBP-C content and/or the expression of truncated MyBP-C from the mutant allele and determine how these mutations effect myofilament sliding in human myocardium. METHODS AND RESULTS: Septal wall tissue samples were obtained from HCM patients undergoing myectomy (n = 18) and donor controls (n = 8). The HCM samples contained 40% less MyBP-C and reduced levels of MyBP-C phosphorylation, when compared to the donor control samples using quantitative mass spectrometry. These differences occurred in the absence of changes in the stoichiometry of other myofilament proteins or production of truncated MyBP-C from the mutant MYBPC3 allele. The functional impact of MYBPC3 truncation mutations on myofilament sliding was determined using a total internal reflection microscopy (TIRFM) single particle assay. Myosin-thick filaments containing their native complement of MyBP-C, and actin-thin filaments decorated with the troponin/tropomyosin calcium regulatory proteins, were isolated from a subgroup of the HCM (n = 4) and donor (n = 5) heart samples. The maximal sliding velocity of native thin filaments was enhanced within the C-zones of the native thick filaments isolated from the HCM samples, when compared to velocity within the C-zones of thick filaments isolated from the donor samples. Analytical modeling demonstrated that the 40% reduction in MyBP-C content was sufficient to enhance the myofilament sliding velocity, as observed in the TIRFM assay. CONCLUSIONS: HCM-causing MYBPC3 truncation mutations result in a loss of MyBP-C content that enhances maximal myofilament sliding velocities, only where MyBP-C is localized within the C-zone. These findings support therapeutic rationale for restoring normal levels of MyBP-C and/or dampening maximal contractile velocities for the treatment of human HCM.

Peer-Led Team Learning Helps Minority Students Succeed.

Active learning methods have been shown to be superior to traditional lecture in terms of student achievement, and our findings on the use of Peer-Led Team Learning (PLTL) concur. Students in our introductory biology course performed significantly better if they engaged in PLTL. There was also a drastic reduction in the failure rate for underrepresented minority (URM) students with PLTL, which further resulted in closing the achievement gap between URM and non-URM students. With such compelling findings, we strongly encourage the adoption of Peer-Led Team Learning in undergraduate Science, Technology, Engineering, and Mathematics (STEM) courses.

Acute Care Patient Portal Intervention: Portal Use and Patient Activation.

BACKGROUND: Patient-facing health information technology (HIT) tools, such as patient portals, are recognized as a potential mechanism to facilitate patient engagement and patient-centered care, yet the use of these tools remains limited in the hospital setting. Although research in this area is growing, it is unclear how the use of acute care patient portals might affect outcomes, such as patient activation. OBJECTIVE: The aim of this study was to describe the use of an acute care patient portal and investigate its association with patient and care partner activation in the hospital setting. METHODS: We implemented an acute care patient portal on 6 acute care units over an 18-month period. We investigated the characteristics of the users (patients and their care partners) of the patient portal, as well as their use of the portal. This included the number of visits to each page, the number of days used, the length of the user's access period, and the average percent of days used during the access period. Patient and care partner activation was assessed using the short form of the patient activation measure (PAM-13) and the caregiver patient activation measure (CG-PAM). Comparisons of the activation scores were performed using propensity weighting and robust weighted linear regression. RESULTS: Of the 2974 randomly sampled patients, 59.01% (1755/2974) agreed to use the acute care patient portal. Acute care patient portal enrollees were younger, less sick, less likely to have Medicare as their insurer, and more likely to use the Partners Healthcare enterprise ambulatory patient portal (Patient Gateway). The most used features of the acute care patient portal were the laboratory test results, care team information, and medication list. Most users accessed the portal between 1 to 4 days during their hospitalization, and the average number of days used (logged in at least once per day) was 1.8 days. On average, users accessed the portal 42.69% of the hospital days during which it was available. There was significant association with patient activation on the neurology service (P<.001) and medicine service (P=.01), after the introduction of HIT tools and the acute care patient portal, but not on the oncology service. CONCLUSIONS: Portal users most often accessed the portal to view their clinical information, though portal usage was limited to only the first few days of enrollment. We found an association between the use of the portal and HIT tools with improved levels of patient activation. These tools may help facilitate patient engagement and improve outcomes when fully utilized by patients and care partners. Future study should leverage usage metrics to describe portal use and assess the impact of HIT tools on specific outcome measures in the hospital setting.

Kremen1 regulates the regenerative capacity of support cells and mechanosensory hair cells in the zebrafish lateral line.

Mechanosensory hair cells in the inner ear mediate the sensations of hearing and balance, and in the specialized lateral line sensory system of aquatic vertebrates, the sensation of water movement. In mammals, hair cells lack the ability to regenerate following damage, resulting in sensory deficits. In contrast, non-mammalian vertebrates, such as zebrafish, can renew hair cells throughout their lifespan. Wnt signaling is required for development of inner ear and lateral line hair cells and regulates regeneration. Kremen1 inhibits Wnt signaling and hair cell formation, though its role in regeneration is unknown. We used a zebrafish kremen1 mutant line to show overactive Wnt signaling results in supernumerary support cells and hair cell regeneration without increased proliferation, in contrast with the previously described role of Wnt signaling during hair cell regeneration. This work allows us to understand the biology of mechanosensory hair cells and how regeneration might be promoted following damage.

Peer-led team learning in an undergraduate biology course: Impacts on recruitment, retention, and imposter phenomenon.

OBJECTIVES: The data presented in this note were collected during a multi-year project conducted in the context of large-enrollment introductory biology course at a large private R-1 research institution in the Northeastern United States. The project aimed to examine the impact of Peer-Led Team Learning (PLTL) on the recruitment and retention of marginalized groups in Science, Technology, Engineering, and Mathematics (STEM) majors. While several results from the project have been published, additional data of interest have yet to be reported. This data note reports on additional associations between PLTL participation and improved outcomes for students from groups that have historically been excluded in STEM. Additional data reported herein were collected to determine if students in the course experienced imposter phenomenon, and whether PLTL may be associated with reduced levels of imposter feelings. DATA DESCRIPTION: The data in this note includes academic information such as final course grades and academic level; socio-demographic information such as gender identity, minority status, and first-generation status; and information on student recruitment, retention, imposter feelings, and participation in Peer-Led Team Learning (PLTL). These data might be useful and of value to education researchers and undergraduate STEM instructors who are interested in improving equity in STEM education.

Electronic alerts for ambulatory patients with atrial fibrillation not prescribed anticoagulation: A randomized, controlled trial (AF-ALERT2).

BACKGROUND: Despite widely available risk stratification tools, safe and effective anticoagulants, and guideline recommendations, anticoagulation for stroke prevention in atrial fibrillation (AF) is under-prescribed in ambulatory patients. To assess the impact of alert-based computerized decision support (CDS) on anticoagulation prescription in ambulatory patients with AF and high-risk for stroke, we conducted this randomized controlled trial. METHODS: Patients with AF and CHA2DS2-VASc score ≥ 2 who were not prescribed anticoagulation and had a clinic visit at Brigham and Women's Hospital were enrolled. Patients were randomly allocated, according to Attending Physician of record, to intervention (alert-based CDS) versus control (no notification). The primary efficacy outcome was the frequency of anticoagulant prescription. RESULTS: The CDS tool assigned 395 and 403 patients to the alert and control groups, respectively. Alert patients were more likely to be prescribed anticoagulation within 48 h of the clinic visit (15.4 % vs. 7.7 %, p < 0.001) and at 90 days (17.2 % vs. 9.9 %, p < 0.01). Direct oral anticoagulants were the predominantly prescribed form of anticoagulation. No significant differences were observed in stroke, TIA, or systemic embolic events (0 % vs. 0.8 %, p = 0.09), symptomatic VTE (0.5 % vs. 1 %, p = 0.43), all-cause mortality (2 % vs. 0.7 %, p = 0.12), or major adverse cardiovascular events (2.8 % vs. 2.5 %, p = 0.79) at 90 days. CONCLUSIONS: An alert-based CDS strategy increased a primary efficacy outcome of anticoagulation in clinic patients with AF and high-risk for stroke who were not receiving anticoagulation at the time of the office visit. The study was likely underpowered to assess an impact on clinical outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier- NCT02958943.

Determining the impact of vaccination on SARS-CoV-2 RT-PCR cycle threshold values and infectious viral titres.

Background: As the COVID-19 pandemic continues, efforts to better understand severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral shedding and transmission in both unvaccinated and vaccinated populations remain critical to informing public health policies and vaccine development. The utility of using real time RT-PCR cycle threshold values (CT values) as a proxy for infectious viral litres from individuals infected with SARS-CoV-2 is yet to be fully understood. This retrospective observational cohort study compares quantitative infectious viral litres derived from a focus-forming viral titre assay with SARS-CoV-2 RT-PCR CT values in both unvaccinated and vaccinated individuals infected with the Delta strain. Methods: Nasopharyngeal swabs positive for SARS-CoV-2 by RT-PCR with a CT value <27 collected from 26 June to 17 October 2021 at the University of Vermont Medical Center Clinical Laboratory for which vaccination records were available were included. Partially vaccinated and individuals <18 years of age were excluded. Infectious viral litres were determined using a micro-focus forming assay under BSL-3 containment. Results: In total, 119 specimens from 22 unvaccinated and 97 vaccinated individuals met all inclusion criteria and had sufficient residual volume to undergo viral titring. A negative correlation between RT-PCR CT values and viral litres was observed in both unvaccinated and vaccinated groups. No difference in mean CT value or viral titre was detected between vaccinated and unvaccinated groups. Viral litres did not change as a function of time since vaccination. Conclusions: Our results add to the growing body of knowledge regarding the correlation of SARS-CoV-2 RNA levels and levels of infectious virus. At similar CT values, vaccination does not appear to impact an individual's potential infectivity when infected with the Delta variant.

Unique Patient-Reported Hospital Safety Concerns With Online Tool: MySafeCare.

BACKGROUND: Hospitalized patients and their care partners have valuable and unique perspectives of the medical care they receive. Direct and real-time reporting of patients' safety concerns, though limited in the acute care setting, could provide opportunities to improve patient care. METHODS: We implemented the MySafeCare (MSC) application on six acute care units for 18 months as part of a patient-centered health information technology intervention to promote engagement and safety in the acute care setting. The web-based application allowed hospitalized patients to submit safety concerns anonymously and in real time. We describe characteristics of patient submissions including their categorizations. We evaluated rates of submissions to MSC and compared them with rates of submissions to the Patient Family Relations department at the hospital. In addition, we performed thematic analysis of narrative concerns submitted to the application. RESULTS: We received 46 submissions to MSC and 33% of concerns received were anonymous. The overall rate of submissions was 0.6 submissions per 1000 patient-days and was considerably lower than the rate of submissions to the Patient Family Relations during the same period (4.1 per 1000 patient-days). Identified themes of narrative concerns included unmet care needs and preferences, inadequate communication, and concerns about safety of care. CONCLUSIONS: Although the submission rate to the application was low, MSC captured important content directly from hospitalized patients or their care partners. A web-based patient safety reporting tool for patients should be studied further to understand patient and care partner use and willingness to engage, as well as potential effects on patient safety outcomes.

Extended-Duration Low-Intensity Apixaban to Prevent Recurrence in Patients with Provoked Venous Thromboembolism and Enduring Risk Factors: Rationale and Design of the HI-PRO Trial.

Patients with acute venous thromboembolism (VTE) in the setting of transient provoking factors are typically treated with short-term anticoagulation. However, the risk of recurrence may be increased in the presence of enduring risk factors. In such patients, the optimal duration of treatment remains uncertain. HI-PRO is a single-center, double-blind randomized trial. Patients with deep vein thrombosis (DVT) or pulmonary embolism (PE) following a major provoking factor, including major surgery or major trauma, who completed at least 3 months of standard-dose therapeutic anticoagulation and have at least one enduring risk factor (such as obesity or heart failure) will be considered for inclusion. Patients will be randomized to apixaban 2.5 mg twice daily or placebo for 12 months. The primary efficacy outcome will be symptomatic recurrent VTE-a composite of DVT and/or PE at 12 months after randomization. Secondary efficacy outcomes include a composite of death due to cardiovascular causes, nonfatal myocardial infarction, stroke or systemic embolism, major adverse limb events, or coronary or peripheral ischemia requiring revascularization at 12 months, and individual components of these outcomes. The primary safety outcome is major bleeding according to the International Society on Thrombosis and Haemostasis definition. The study plans to enroll 600 patients (300 per arm) to have 80% power for detecting a 75% relative risk reduction in the primary outcome. Active recruitment began in March 2021. HI-PRO will provide clinically meaningful data on whether patients with provoked VTE and enduring risk factors have fewer adverse clinical outcomes if prescribed low-intensity extended-duration anticoagulation.

Patients with myeloproliferative neoplasms and COVID-19 have increased rates of arterial thrombosis.

Background: Both coronavirus disease-2019 (COVID-19) and myeloproliferative neoplasms (MPNs) are associated with systemic inflammation and risk of thrombosis. Risk of thrombosis in patients with COVID with and without MPNs has not been extensively studied. Methods: Retrospective cohort study of 44 patients with MPNs and 1114 patients without MPNs positive for SARS-COV-2. Outcomes were arterial thrombosis (AT), venous thromboembolism (VTE), bleeding, and death. Time-to-event analysis was performed using competing risk regression model and Cox proportional hazards. Results: AT occurred more frequently in patients with MPN (7% vs. 1%, p = 0.03). Rates of VTE (7% vs. 5%, p = 0.73), bleeding (7% vs. 2%, p = 0.06), and death (9% vs. 6%, p = 0.32) were similar. MPN patients were older and had more cardiovascular comorbidities. After time-to-event competing-risk regression adjusting for age, MPN patients had higher risk of AT (subdivision hazards ratio 3.95, 95% CI 1.09-14.39) but not VTE, bleeding, or death. Conclusions: Among patients with COVID-19, MPN patients had higher risk of arterial thrombosis but not VTE, bleeding, and death compared with non-MPN patients. Larger studies are needed to confirm our findings given the limited sample size.

Mutant Frizzled 4 associated with vitreoretinopathy traps wild-type Frizzled in the endoplasmic reticulum by oligomerization.

nt signalling pathways regulate cell proliferation, cell fate and morphogenetic movements. Here, we demonstrate that the Frizzled (Fz) family of Wnt receptors, similarly to G-protein-coupled receptors (GPCRs), form specific homo- and hetero-oligomers. Two lines of evidence suggest that oligomerization occurs in the endoplasmic reticulum: first, a mutant allele of Fz4, encoding a truncated protein that is retained in the endoplasmic reticulum, is linked to the autosomal-dominant retinal degenerative disease, familial exudative vitreoretinopathy (FEVR). We show that this mutant form of Fz4 oligomerizes with wild-type Fz4, retains it in the endoplasmic reticulum and inhibits its signalling. Second, a derivative of Fz1 targeted to the endoplasmic reticulum traps wild-type Fz1 in the endoplasmic reticulum and blocks its signalling. These data support the hypothesis that oligomerization of mutant and wild-type Fz proteins occurs in the endoplasmic reticulum and may explain the genetic dominance of this FEVR allele.

Impact of Atrial Fibrillation on In-Hospital Mortality and Stroke in Acute Aortic Syndromes.

BACKGROUND: Acute aortic syndromes may present with a number of cardiovascular complications, including atrial fibrillation. We assessed the prevalence of atrial fibrillation in patients presenting with acute aortic syndromes and evaluated atrial fibrillation's association with in-hospital mortality and stroke. METHODS: Consecutive patients with acute aortic syndromes admitted to a single tertiary care center from January 2015 to March 2020 were included. We identified patients with atrial fibrillation on the presenting electrocardiogram. RESULTS: A total of 309 patients with acute aortic syndromes were included in our analyses: 148 (48%) presented with Stanford type A and 161 (52%) with Stanford type B acute aortic syndromes. Twenty-seven (8.7%) patients had atrial fibrillation on the presenting electrocardiogram: 12 (44%) with type A and 15 (56%) with type B acute aortic syndromes. Patients with atrial fibrillation were older, more likely to be white, had a higher frequency of history of cancer, peripheral artery disease, cerebrovascular disease, and heart failure with preserved ejection fraction, compared with those without atrial fibrillation. Acute aortic syndromes patients with atrial fibrillation had higher frequencies of in-hospital mortality compared with those without atrial fibrillation (40.7% vs 12.4%, P < .0001). However, stroke frequencies did not differ between the 2 groups. CONCLUSION: In patients presenting with acute aortic syndromes and atrial fibrillation, we observed higher frequencies of in-hospital mortality, without differences in the frequencies of stroke.

Glycogen Metabolism Supports Early Glycolytic Reprogramming and Activation in Dendritic Cells in Response to Both TLR and Syk-Dependent CLR Agonists.

Dendritic cells (DCs) increase their metabolic dependence on glucose and glycolysis to support their maturation, activation-associated cytokine production, and T-cell stimulatory capacity. We have previously shown that this increase in glucose metabolism can be initiated by both Toll-like receptor (TLR) and C-type lectin receptor (CLR) agonists. In addition, we have shown that the TLR-dependent demand for glucose is partially satisfied by intracellular glycogen stores. However, the role of glycogen metabolism in supporting CLR-dependent DC glycolytic demand has not been formally demonstrated. In this work, we have shown that DCs activated with fungal-associated ß-glucan ligands exhibit acute glycolysis induction that is dependent on glycogen metabolism. Furthermore, glycogen metabolism supports DC maturation, inflammatory cytokine production, and priming of the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome in response to both TLR- and CLR-mediated activation. These data support a model in which different classes of innate immune receptors functionally converge in their requirement for glycogen-dependent glycolysis to metabolically support early DC activation. These studies provide new insight into how DC immune effector function is metabolically regulated in response to diverse inflammatory stimuli.

Registry of Arterial and Venous Thromboembolic Complications in Patients With COVID-19.

BACKGROUND: Cardiovascular complications, including myocardial infarction, ischemic stroke, and pulmonary embolism, represent an important source of adverse outcomes in coronavirus disease-2019 (COVID-19). OBJECTIVES: To assess the frequency of arterial and venous thromboembolic disease, risk factors, prevention and management patterns, and outcomes in patients with COVID-19, the authors designed a multicenter, observational cohort study. METHODS: We analyzed a retrospective cohort of 1,114 patients with COVID-19 diagnosed through our Mass General Brigham integrated health network. The total cohort was analyzed by site of care: intensive care (n = 170); hospitalized nonintensive care (n = 229); and outpatient (n = 715). The primary study outcome was a composite of adjudicated major arterial or venous thromboembolism. RESULTS: Patients with COVID-19 were 22.3% Hispanic/Latinx and 44.2% non-White. Cardiovascular risk factors of hypertension (35.8%), hyperlipidemia (28.6%), and diabetes (18.0%) were common. Prophylactic anticoagulation was prescribed in 89.4% of patients with COVID-19 in the intensive care cohort and 84.7% of those in the hospitalized nonintensive care setting. Frequencies of major arterial or venous thromboembolism, major cardiovascular adverse events, and symptomatic venous thromboembolism were highest in the intensive care cohort (35.3%, 45.9%, and 27.0 %, respectively) followed by the hospitalized nonintensive care cohort (2.6%, 6.1%, and 2.2%, respectively) and the outpatient cohort (0% for all). CONCLUSIONS: Major arterial or venous thromboembolism, major adverse cardiovascular events, and symptomatic venous thromboembolism occurred with high frequency in patients with COVID-19, especially in the intensive care setting, despite a high utilization rate of thromboprophylaxis.

Development and Validation of WeCares, a Survey Instrument to Assess Hospitalized Patients' and Family Members' "Willingness to Engage in Your Care and Safety".

BACKGROUND: Patient engagement is recognized as a method to improve care quality and safety. A research team developed WeCares (Willingness to Engage in Your Care and Safety), a survey instrument assessing patients' and families' engagement in the safety of their care during their hospital stay. The objective of this study is to establish the preliminary construct validity and internal consistency of WeCares. METHODS: WeCares was distributed to patients and families. With the survey responses, exploratory factor analysis (EFA) was performed to identify the factorial structure of WeCares. The internal consistency was assessed using Cronbach's alpha. Descriptive and comparative analysis was also performed to summarize patients' and families' responses. RESULTS: A total of 247 patients and families responded to the WeCare survey, of which 224 were used for EFA. EFA resulted in a 13-item, four-factor structure, including (1) comfortable sharing concerns, (2) responsibility for preventing errors, (3) perception of care team members' attitude, and (4) patients'/families' role in preventing errors. The Cronbach alphas were 0.716-0.866, indicating acceptable internal consistency. Overall, patients and families were comfortable sharing concerns with clinicians but preferred to remain anonymous. They believed that the care team members hold most responsibility for error prevention, however, and agreed on their ability to help prevent errors. CONCLUSION: WeCares was developed to assess patients' and families' willingness to engage. WeCares can also be used to facilitate conversation about safety concerns and shared responsibility. The study team believes this would lead to patient activation in guarding their own care and ultimately improve patient outcomes and safety.

The wtf4 meiotic driver utilizes controlled protein aggregation to generate selective cell death.

Meiotic drivers are parasitic loci that force their own transmission into greater than half of the offspring of a heterozygote. Many drivers have been identified, but their molecular mechanisms are largely unknown. The wtf4 gene is a meiotic driver in Schizosaccharomyces pombe that uses a poison-antidote mechanism to selectively kill meiotic products (spores) that do not inherit wtf4. Here, we show that the Wtf4 proteins can function outside of gametogenesis and in a distantly related species, Saccharomyces cerevisiae. The Wtf4poison protein forms dispersed, toxic aggregates. The Wtf4antidote can co-assemble with the Wtf4poison and promote its trafficking to vacuoles. We show that neutralization of the Wtf4poison requires both co-assembly with the Wtf4antidote and aggregate trafficking, as mutations that disrupt either of these processes result in cell death in the presence of the Wtf4 proteins. This work reveals that wtf parasites can exploit protein aggregate management pathways to selectively destroy spores.

Meiotic drivers are genes that break the normal rules of inheritance. Usually, a gene has a 50% chance of passing on to the next generation. Meiotic drivers force their way into the next generation by poisoning the gametes (the sex cells that combine to form a zygote) that do not carry them. Harnessing the power of genetic drivers could allow scientists to spread beneficial genes across populations. One group of meiotic drivers found in fission yeast is called the 'with transposon fission yeast', or 'wtf' gene family. The wtf drivers act during the production of spores, which are the fission yeast equivalent of sperm, and they encode both a poison that can destroy the spores and its antidote. The poison spreads through the sac holding the spores, and can affect all of them, while the antidote only protects the spores that make it. This means that the spores carrying the wtf genes survive, while the rest of the spores are killed. To understand whether it is possible to use the wtf meiotic drivers to spread other genes, perhaps outside of fission yeast, scientists must first establish exactly how the proteins coded for by genes behave. To do this, Nuckolls et al. examined a member of the wtf family called wtf4. Attaching a fluorescent label to the poison and antidote proteins produced by wtf4 made it possible to see what they do. This revealed that the poison clumps, forming toxic aggregates that damage yeast spores. The antidote works by mopping up these aggregates and moving them to the cell's main storage compartment, called the vacuole. Mutations that disrupted the ability of the antidote to interact with the poison or its ability to move the poison into storage stopped the antidote from working. Nuckolls et al. also showed that if genetic engineering was used to introduce wtf4 into a distantly related species of budding yeast the effects of this meiotic driver were the same. This suggests that the wtf genes may be good candidates for future genetic engineering experiments. Engineered systems known as 'gene drives' could spread beneficial genetic traits through populations. This could include disease-resistance genes in crops, or disease-preventing genes in mosquitoes. The wtf genes are small and work independently of other genes, making them promising candidates for this type of system. These experiments also suggest that the wtf genes could be useful for understanding why clumps of proteins are toxic to cells. Future work could explore why clumps of wtf poison kill spores, while clumps of poison plus antidote do not. This could aid research into human ailments caused by protein clumps, such as Huntington's or Alzheimer's disease.

Syk-dependent glycolytic reprogramming in dendritic cells regulates IL-1ß production to ß-glucan ligands in a TLR-independent manner.

Dendritic cells (DCs) activated via TLR ligation experience metabolic reprogramming, in which the cells are heavily dependent on glucose and glycolysis for the synthesis of molecular building blocks essential for maturation, cytokine production, and the ability to stimulate T cells. Although the TLR-driven metabolic reprogramming events are well documented, fungal-mediated metabolic regulation via C-type lectin receptors such as Dectin-1 and Dectin-2 is not clearly understood. Here, we show that activation of DCs with fungal-associated ß-glucan ligands induces acute glycolytic reprogramming that supports the production of IL-1ß and its secretion subsequent to NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activation. This acute glycolytic induction in response to ß-glucan ligands requires spleen tyrosine kinase signaling in a TLR-independent manner, suggesting now that different classes of innate immune receptors functionally induce conserved metabolic responses to support immune cell activation. These studies provide new insight into the complexities of metabolic regulation of DCs immune effector function regarding cellular activation associated with protection against fungal microbes.