APOE4/4 is linked to damaging lipid droplets in Alzheimer's disease microglia.

Several genetic risk factors for Alzheimer's disease implicate genes involved in lipid metabolism and many of these lipid genes are highly expressed in glial cells1. However, the relationship between lipid metabolism in glia and Alzheimer's disease pathology remains poorly understood. Through single-nucleus RNA sequencing of brain tissue in Alzheimer's disease, we have identified a microglial state defined by the expression of the lipid droplet-associated enzyme ACSL1 with ACSL1-positive microglia being most abundant in patients with Alzheimer's disease having the APOE4/4 genotype. In human induced pluripotent stem cell-derived microglia, fibrillar Aß induces ACSL1 expression, triglyceride synthesis and lipid droplet accumulation in an APOE-dependent manner. Additionally, conditioned media from lipid droplet-containing microglia lead to Tau phosphorylation and neurotoxicity in an APOE-dependent manner. Our findings suggest a link between genetic risk factors for Alzheimer's disease with microglial lipid droplet accumulation and neurotoxic microglia-derived factors, potentially providing therapeutic strategies for Alzheimer's disease.

Congenital heart defects caused by FOXJ1.

FOXJ1 is expressed in ciliated cells of the airways, testis, oviduct, central nervous system and the embryonic left-right organizer. Ablation or targeted mutation of Foxj1 in mice, zebrafish and frogs results in loss of ciliary motility and/or reduced length and number of motile cilia, affecting the establishment of the left-right axis. In humans, heterozygous pathogenic variants in FOXJ1 cause ciliopathy leading to situs inversus, obstructive hydrocephalus and chronic airway disease. Here, we report a novel truncating FOXJ1 variant (c.784_799dup; p.Glu267Glyfs*12) identified by clinical exome sequencing from a patient with isolated congenital heart defects (CHD) which included atrial and ventricular septal defects, double outlet right ventricle (DORV) and transposition of the great arteries. Functional experiments show that FOXJ1 c.784_799dup; p.Glu267Glyfs*12, unlike FOXJ1, fails to induce ectopic cilia in frog epidermis in vivo or to activate the ADGB promoter, a downstream target of FOXJ1 in cilia, in transactivation assays in vitro. Variant analysis of patients with heterotaxy or heterotaxy-related CHD indicates that pathogenic variants in FOXJ1 are an infrequent cause of heterotaxy. Finally, we characterize embryonic-stage CHD in Foxj1 loss-of-function mice, demonstrating randomized heart looping. Abnormal heart looping includes reversed looping (dextrocardia), ventral looping and no looping/single ventricle hearts. Complex CHDs revealed by histological analysis include atrioventricular septal defects, DORV, single ventricle defects as well as abnormal position of the great arteries. These results indicate that pathogenic variants in FOXJ1 can cause isolated CHD.

Recessively Inherited Deficiency of Secreted WFDC2 (HE4) Causes Nasal Polyposis and Bronchiectasis.

Rationale: Bronchiectasis is a pathological dilatation of the bronchi in the respiratory airways associated with environmental or genetic causes (e.g., cystic fibrosis, primary ciliary dyskinesia, and primary immunodeficiency disorders), but most cases remain idiopathic. Objectives: To identify novel genetic defects in unsolved cases of bronchiectasis presenting with severe rhinosinusitis, nasal polyposis, and pulmonary Pseudomonas aeruginosa infection. Methods: DNA was analyzed by next-generation or targeted Sanger sequencing. RNA was analyzed by quantitative PCR and single-cell RNA sequencing. Patient-derived cells, cell cultures, and secretions (mucus, saliva, seminal fluid) were analyzed by Western blotting and immunofluorescence microscopy, and mucociliary activity was measured. Blood serum was analyzed by electrochemiluminescence immunoassay. Protein structure and proteomic analyses were used to assess the impact of a disease-causing founder variant. Measurements and Main Results: We identified biallelic pathogenic variants in WAP four-disulfide core domain 2 (WFDC2) in 11 individuals from 10 unrelated families originating from the United States, Europe, Asia, and Africa. Expression of WFDC2 was detected predominantly in secretory cells of control airway epithelium and also in submucosal glands. We demonstrate that WFDC2 is below the limit of detection in blood serum and hardly detectable in samples of saliva, seminal fluid, and airway surface liquid from WFDC2-deficient individuals. Computer simulations and deglycosylation assays indicate that the disease-causing founder variant p.Cys49Arg structurally hampers glycosylation and, thus, secretion of mature WFDC2. Conclusions: WFDC2 dysfunction defines a novel molecular etiology of bronchiectasis characterized by the deficiency of a secreted component of the airways. A commercially available blood test combined with genetic testing allows its diagnosis.

The role of SPAG1 in the assembly of axonemal dyneins in human airway epithelia.

Mutations in SPAG1, a dynein axonemal assembly factor (DNAAF) that facilitates the assembly of dynein arms in the cytoplasm before their transport into the cilium, result in primary ciliary dyskinesia (PCD), a genetically heterogenous disorder characterized by chronic oto-sino-pulmonary disease, infertility and laterality defects. To further elucidate the role of SPAG1 in dynein assembly, we examined its expression, interactions and ciliary defects in control and PCD human airway epithelia. Immunoprecipitations showed that SPAG1 interacts with multiple DNAAFs, dynein chains and canonical components of the R2TP complex. Protein levels of dynein heavy chains (DHCs) and interactions between DHCs and dynein intermediate chains (DICs) were reduced in SPAG1 mutants. We also identified a previously uncharacterized 60 kDa SPAG1 isoform, through examination of PCD subjects with an atypical ultrastructural defect for SPAG1 variants, that can partially compensate for the absence of full-length SPAG1 to assemble a reduced number of outer dynein arms. In summary, our data show that SPAG1 is necessary for axonemal dynein arm assembly by scaffolding R2TP-like complexes composed of several DNAAFs that facilitate the folding and/or binding of the DHCs to the DIC complex.

Correction: Time to revisit the endpoint dilution assay and to replace the TCID50 as a measure of a virus sample's infection concentration.

[This corrects the article DOI: 10.1371/journal.pcbi.1009480.].

Development of a comprehensive approach to adult hereditary cancer testing in Ontario.

BACKGROUND: Genetic testing for hereditary cancer susceptibility has advanced over time due to the discovery of new risk genes, improved technology and decreased cost. In the province of Ontario, testing eligibility criteria were initially developed to include hereditary breast, ovarian and colorectal cancer syndromes. The rapid evolution of genetic technologies has facilitated the ability to interrogate a large number of genes concurrently. This, coupled with new knowledge about risk genes, necessitated a coordinated approach to expanding the scope of genes and indications tested and synchronisation of access and test utilisation across the province as required in a publicly funded universal healthcare system. METHODS: Ontario Health-Cancer Care Ontario convened expert working groups to develop a standardised and comprehensive cancer gene list for adults and accompanying hereditary cancer testing (HCT) criteria using an evidence-based framework and broad laboratory and clinical genetics engagement. RESULTS: A standardised 76-cancer-gene panel, organised into 13 larger disease site panels and 25 single/small gene panels, was developed and endorsed by the working groups. Provincial genetic testing eligibility criteria were updated to align with the new panels and to guide clinical decision-making. In the first year following the implementation of these changes, 10 564 HCT panels were performed with an overall mutation detection rate of 12.2%. CONCLUSION: Using an evidence framework and broad clinical engagement to develop and endorse an updated guidance document, cancer genetic testing for adults in Ontario is now standardised and coordinated across the province.

Dnmt3a deficiency in the skin causes focal, canonical DNA hypomethylation and a cellular proliferation phenotype.

DNA hypomethylation is a feature of epidermal cells from aged and sun-exposed skin, but the mechanisms responsible for this methylation loss are not known. Dnmt3a is the dominant de novo DNA methyltransferase in the skin; while epidermal Dnmt3a deficiency creates a premalignant state in which keratinocytes are more easily transformed by topical mutagens, the conditions responsible for this increased susceptibility to transformation are not well understood. Using whole genome bisulfite sequencing, we identified a focal, canonical DNA hypomethylation phenotype in the epidermal cells of Dnmt3a-deficient mice. Single-cell transcriptomic analysis revealed an increased proportion of cells with a proliferative gene expression signature, while other populations in the skin were relatively unchanged. Although total DNMT3A deficiency has not been described in human disease states, rare patients with an overgrowth syndrome associated with behavioral abnormalities and an increased risk of cancer often have heterozygous, germline mutations in DNMT3A that reduce its function (Tatton-Brown Rahman syndrome [TBRS]). We evaluated the DNA methylation phenotype of the skin from a TBRS patient with a germline DNMT3AR882H mutation, which encodes a dominant-negative protein that reduces its methyltransferase function by ∼80%. We detected a focal, canonical hypomethylation phenotype that revealed considerable overlap with hypomethylated regions found in Dnmt3a-deficient mouse skin. Together, these data suggest that DNMT3A loss creates a premalignant epigenetic state associated with a hyperproliferative phenotype in the skin and further suggest that DNMT3A acts as a tumor suppressor in the skin.

Access to publicly funded weight management services in England using routine data from primary and secondary care (2007-2020): An observational cohort study.

BACKGROUND: Adults living with overweight/obesity are eligible for publicly funded weight management (WM) programmes according to national guidance. People with the most severe and complex obesity are eligible for bariatric surgery. Primary care plays a key role in identifying overweight/obesity and referring to WM interventions. This study aimed to (1) describe the primary care population in England who (a) are referred for WM interventions and (b) undergo bariatric surgery and (2) determine the patient and GP practice characteristics associated with both. METHODS AND FINDINGS: An observational cohort study was undertaken using routinely collected primary care data in England from the Clinical Practice Research Datalink linked with Hospital Episode Statistics. During the study period (January 2007 to June 2020), 1,811,587 adults met the inclusion criteria of a recording of overweight/obesity in primary care, of which 54.62% were female and 20.10% aged 45 to 54. Only 56,783 (3.13%) were referred to WM, and 3,701 (1.09% of those with severe and complex obesity) underwent bariatric surgery. Multivariable Poisson regression examined the associations of demographic, clinical, and regional characteristics on the likelihood of WM referral and bariatric surgery. Higher body mass index (BMI) and practice region had the strongest associations with both outcomes. People with BMI ≥40 kg/m2 were more than 6 times as likely to be referred for WM (10.05% of individuals) than BMI 25.0 to 29.9 kg/m2 (1.34%) (rate ratio (RR) 6.19, 95% confidence interval (CI) [5.99,6.40], p < 0.001). They were more than 5 times as likely to undergo bariatric surgery (3.98%) than BMI 35.0 to 40.0 kg/m2 with a comorbidity (0.53%) (RR 5.52, 95% CI [5.07,6.02], p < 0.001). Patients from practices in the West Midlands were the most likely to have a WM referral (5.40%) (RR 2.17, 95% CI [2.10,2.24], p < 0.001, compared with the North West, 2.89%), and practices from the East of England least likely (1.04%) (RR 0.43, 95% CI [0.41,0.46], p < 0.001, compared with North West). Patients from practices in London were the most likely to undergo bariatric surgery (2.15%), and practices in the North West the least likely (0.68%) (RR 3.29, 95% CI [2.88,3.76], p < 0.001, London compared with North West). Longer duration since diagnosis with severe and complex obesity (e.g., 1.67% of individuals diagnosed in 2007 versus 0.34% in 2015, RR 0.20, 95% CI [0.12,0.32], p < 0.001), and increasing comorbidities (e.g., 2.26% of individuals with 6+ comorbidities versus 1.39% with none (RR 8.79, 95% CI [7.16,10.79], p < 0.001) were also strongly associated with bariatric surgery. The main limitation is the reliance on overweight/obesity being recorded within primary care records to identify the study population. CONCLUSIONS: Between 2007 and 2020, a very small percentage of the primary care population eligible for WM referral or bariatric surgery according to national guidance received either. Higher BMI and GP practice region had the strongest associations with both. Regional inequalities may reflect differences in commissioning and provision of WM services across the country. Multi-stakeholder qualitative research is ongoing to understand the barriers to accessing WM services and potential solutions. Together with population-wide prevention strategies, improved access to WM interventions is needed to reduce obesity levels.

What effect have commissioners' policies for body mass index had on hip replacement surgery?: an interrupted time series analysis from the National Joint Registry for England.

BACKGROUND: Despite their widespread use, the impact of commissioners' policies for body mass index (BMI) for access to elective surgery is not clear. Policy use varies by locality, and there are concerns that these policies may worsen health inequalities. The aim of this study was to assess the impact of policies for BMI on access to hip replacement surgery in England. METHODS: A natural experimental study using interrupted time series and difference-in-differences analysis. We used National Joint Registry data for 480,364 patients who had primary hip replacement surgery in England between January 2009 and December 2019. Clinical commissioning group policies introduced before June 2018 to alter access to hip replacement for patients with overweight or obesity were considered the intervention. The main outcome measures were rate of surgery and patient demographics (BMI, index of multiple deprivation, independently funded surgery) over time. RESULTS: Commissioning localities which introduced a policy had higher surgery rates at baseline than those which did not. Rates of surgery fell after policy introduction, whereas rates rose in localities with no policy. 'Strict' policies mandating a BMI threshold for access to surgery were associated with the sharpest fall in rates (trend change of - 1.39 operations per 100,000 population aged 40 + per quarter-year, 95% confidence interval - 1.81 to - 0.97, P < 0.001). Localities with BMI policies have higher proportions of independently funded surgery and more affluent patients receiving surgery, indicating increasing health inequalities. Policies enforcing extra waiting time before surgery were associated with worsening mean pre-operative symptom scores and rising obesity. CONCLUSIONS: Commissioners and policymakers should be aware of the counterproductive effects of BMI policies on patient outcomes and inequalities. We recommend that BMI policies involving extra waiting time or mandatory BMI thresholds are no longer used to reduce access to hip replacement surgery.

COVID-19 virtual patient cohort suggests immune mechanisms driving disease outcomes.

To understand the diversity of immune responses to SARS-CoV-2 and distinguish features that predispose individuals to severe COVID-19, we developed a mechanistic, within-host mathematical model and virtual patient cohort. Our results suggest that virtual patients with low production rates of infected cell derived IFN subsequently experienced highly inflammatory disease phenotypes, compared to those with early and robust IFN responses. In these in silico patients, the maximum concentration of IL-6 was also a major predictor of CD8+ T cell depletion. Our analyses predicted that individuals with severe COVID-19 also have accelerated monocyte-to-macrophage differentiation mediated by increased IL-6 and reduced type I IFN signalling. Together, these findings suggest biomarkers driving the development of severe COVID-19 and support early interventions aimed at reducing inflammation.

Neurobiology of ARID1B haploinsufficiency related to neurodevelopmental and psychiatric disorders.

ARID1B haploinsufficiency is a frequent cause of intellectual disability (ID) and autism spectrum disorder (ASD), and also leads to emotional disturbances. In this review, we examine past and present clinical and preclinical research into the neurobiological function of ARID1B. The presentation of ARID1B-related disorders (ARID1B-RD) is highly heterogeneous, including varying degrees of ID, ASD, and physical features. Recent research includes the development of suitable clinical readiness assessments for the treatment of ARID1B-RD, as well as similar neurodevelopmental disorders. Recently developed mouse models of Arid1b haploinsufficiency successfully mirror many of the behavioral phenotypes of ASD and ID. These animal models have helped to solidify the molecular mechanisms by which ARID1B regulates brain development and function, including epigenetic regulation of the Pvalb gene and promotion of Wnt/ß-catenin signaling in neural progenitors in the ventral telencephalon. Finally, preclinical studies have identified the use of a positive allosteric modulator of the GABAA receptor as an effective treatment for some Arid1b haploinsufficiency-related behavioral phenotypes, and there is potential for the refinement of this therapy in order to translate it into clinical use.

Data sharing to improve concordance in variant interpretation across laboratories: results from the Canadian Open Genetics Repository.

BACKGROUND: This study aimed to identify and resolve discordant variant interpretations across clinical molecular genetic laboratories through the Canadian Open Genetics Repository (COGR), an online collaborative effort for variant sharing and interpretation. METHODS: Laboratories uploaded variant data to the Franklin Genoox platform. Reports were issued to each laboratory, summarising variants where conflicting classifications with another laboratory were noted. Laboratories could then reassess variants to resolve discordances. Discordance was calculated using a five-tier model (pathogenic (P), likely pathogenic (LP), variant of uncertain significance (VUS), likely benign (LB), benign (B)), a three-tier model (LP/P are positive, VUS are inconclusive, LB/B are negative) and a two-tier model (LP/P are clinically actionable, VUS/LB/B are not). We compared the COGR classifications to automated classifications generated by Franklin. RESULTS: Twelve laboratories submitted classifications for 44 510 unique variants. 2419 variants (5.4%) were classified by two or more laboratories. From baseline to after reassessment, the number of discordant variants decreased from 833 (34.4% of variants reported by two or more laboratories) to 723 (29.9%) based on the five-tier model, 403 (16.7%) to 279 (11.5%) based on the three-tier model and 77 (3.2%) to 37 (1.5%) based on the two-tier model. Compared with the COGR classification, the automated Franklin classifications had 94.5% sensitivity and 96.6% specificity for identifying actionable (P or LP) variants. CONCLUSIONS: The COGR provides a standardised mechanism for laboratories to identify discordant variant interpretations and reduce discordance in genetic test result delivery. Such quality assurance programmes are important as genetic testing is implemented more widely in clinical care.

Community health impacts after a jet fuel leak contaminated a drinking water system: Oahu, Hawaii, November 2021.

BACKGROUND: In 2021, a large petroleum leak contaminated a water source that supplied drinking water to military and civilians in Oahu, Hawaii. METHODS: We conducted an Assessment of Chemical Exposures (ACE) survey and supplemented that information with complementary data sources: (1) poison center caller records; (2) emergency department visit data; and (3) a key informant questionnaire. RESULTS: Among 2,289 survey participants, 86% reported ≥1 new or worsening symptom, 75% of which lasted ≥30 days, and 37% sought medical care. Most (n = 1,653, 72%) reported new mental health symptoms. Among equally observable symptoms across age groups, proportions of children ≤2 years experiencing vomiting, runny nose, skin rashes, and coughing (33, 46, 56, and 35%, respectively) were higher than other age groups. Poison center calls increased the first 2 weeks after the contamination, while emergency department visits increased in early December 2021. Key informant interviews revealed themes of lack of support, mental health symptoms, and long-term health impact concerns. DISCUSSION: This event led to widespread exposure to petroleum products and negatively affected thousands of people. Follow-up health surveys or interventions should give special consideration to longer-term physical and mental health, especially children due to their unique sensitivity to environmental exposures.

High risk and low prevalence diseases: Testicular torsion.

INTRODUCTION: Testicular torsion is a serious condition that carries with it a high rate of morbidity. OBJECTIVE: This review highlights the pearls and pitfalls of testicular torsion, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence. DISCUSSION: Testicular torsion is a urological emergency that occurs with rotation of the testicle along its supporting ligaments leading to obstruction of vascular flow. A key risk factor is the presence of a bell-clapper deformity. The most common population affected includes children in a bimodal distribution with the most cases occurring in the first year of life and between 12 and 18 years, although cases do occur in adults. Acute, severe, unilateral scrotal pain is the most common presenting symptom. Nausea and vomiting are common, but the presence or absence of a cremasteric reflex is not a reliable indicator of disease. The TWIST score may assist with clinical decision making in patients presenting with acute testicular pain but should not be used in isolation. If torsion is suspected or confirmed, consultation with the urology specialist should not be delayed, as outcomes are time sensitive. Ultrasound can be used for diagnosis, but a normal ultrasound examination cannot exclude the diagnosis. Treatment includes emergent urology consultation for surgical exploration and detorsion, as well as symptomatic therapy in the ED. Manual detorsion can be attempted in the ED while awaiting transfer or consultation. CONCLUSIONS: An understanding of testicular torsion can assist emergency clinicians in diagnosing and managing this disease.

COVID-19 pandemic-associated changes in overall emergency department visits by age group, race, and ethnicity - United States, January 2019-April 2022.

BACKGROUND: ED data are an important source of surveillance data for monitoring many conditions of public health concern and are especially useful in describing trends related to new, or unusual public health events. The COVID-19 pandemic led to significant changes in emergency care seeking behavior. We described the trends in all-cause emergency department (ED) visit volumes by race, ethnicity, and age using ED data from the National Syndromic Surveillance Program (NSSP) during December 30, 2018-April 2, 2022. METHODS: We described total and race, ethnicity, and age group-specific ED visit volumes during the COVID-19 pandemic by comparing quarterly visit volumes during the pandemic period to the relevant quarters in 2019. We quantified the variability of ED visits volumes by calculating the coefficient of variation in mean weekly ED visit volume for each quarter during Q1 2019-Q1 2022. RESULTS: Overall ED visits dropped by 32% during Q2 2020, when the COVID-19 pandemic began, then rebounded to 2019 baseline by Q2 2021. ED visits for all race, ethnicity, and age groups similarly dropped in Q2 2020 and adults of all race and ethnicity groups rebounded to at or above pre-pandemic levels while children remained at or below the pre-pandemic baseline except during Q3 2021. There was larger variation in mean weekly ED visits compared to the respective quarter in 2019 for 6 of 9 quarters during Q1 2020-Q1 2022. CONCLUSIONS: ED utilization fluctuated considerably during the COVID-19 pandemic. Overall ED visits returned to within 5% of 2019 baseline during Q2 2021, however, ED visits among children did not return to the 2019 baseline until Q3 2021, then again dropped below the 2019 baseline in Q4 2021. Trends in ED visit volumes were similar among race and ethnicity groups but differed by age group. Monitoring ED data stratified by race, ethnicity and age can help understand healthcare utilization trends and overall burden on the healthcare system as well as facilitate rapid identification and response to public health threats that may disproportionately affect certain populations.

Access to hip and knee arthroplasty in England: commissioners' policies for body mass index and smoking status and implications for integrated care systems.

BACKGROUND: Commissioning policies are in place in England that alter access to hip and knee arthroplasty based on patients' body mass index and smoking status. Our objectives were to ascertain the prevalence, trend and nature of these policies, and consider the implications for new integrated care systems (ICSs). METHODS: Policy data were obtained from an internet search for all current and historic clinical commissioning group (CCG) hip and knee arthroplasty policies and use of Freedom of Information (FOI) requests to each CCG. Descriptive analyses of policy type, explicit threshold criteria and geography are reported. Estimates were made of the uptake of policies by ICSs based on the modal policy type of their constituent CCGs. RESULTS: There were 106 current and 143 historic CCGs in England at the time of the search in June 2021. Policy information was available online for 56.2% (140/249) CCGs. With the addition of information from FOIs, complete policy information was available for 94.4% (235/249) of CCGs. Prevalence and severity of policies have increased over time. For current CCGs, 67.9% (72/106) had a policy for body mass index (BMI) and 75.5% (80/106) had a policy for smoking status for hip or knee arthroplasty. Where BMI policies were in place, 61.1% (44/72) introduced extra waiting time before surgery or restricted access to surgery based on BMI thresholds (modal threshold: BMI of 40 kg/m2, range 30-45). In contrast, where smoking status policies were in place, most offered patients advice or optional smoking cessation support and only 15% (12/80) introduced extra waiting time or mandatory cessation before surgery. It is estimated that 40% of ICSs may adopt a BMI policy restrictive to access to arthroplasty. CONCLUSIONS: Access policies to arthroplasty based on BMI and smoking status are widespread in England, have increased in prevalence since 2013, and persist within new ICSs. The high variation in policy stringency on BMI between regions is likely to cause inequality in access to arthroplasty and to specialist support for affected patients. Further work should determine the impact of different types of policy on access to surgery and health inequalities.

Prevention and treatment of SHIVAD8 infection in rhesus macaques by a potent d-peptide HIV entry inhibitor.

Cholesterol-PIE12-trimer (CPT31) is a potent d-peptide HIV entry inhibitor that targets the highly conserved gp41 N-peptide pocket region. CPT31 exhibited strong inhibitory breadth against diverse panels of primary virus isolates. In a simian-HIV chimeric virus AD8 (SHIVAD8) macaque model, CPT31 prevented infection from a single high-dose rectal challenge. In chronically infected animals, CPT31 monotherapy rapidly reduced viral load by ∼2 logs before rebound occurred due to the emergence of drug resistance. In chronically infected animals with viremia initially controlled by combination antiretroviral therapy (cART), CPT31 monotherapy prevented viral rebound after discontinuation of cART. These data establish CPT31 as a promising candidate for HIV prevention and treatment.

Remethylation of Dnmt3a-/- hematopoietic cells is associated with partial correction of gene dysregulation and reduced myeloid skewing.

Mutations in the DNA methyltransferase 3A (DNMT3A) gene are the most common cause of age-related clonal hematopoiesis (ARCH) in older individuals, and are among the most common initiating events for acute myeloid leukemia (AML). The most frequent DNMT3A mutation in AML patients (R882H) encodes a dominant-negative protein that reduces methyltransferase activity by ∼80% in cells with heterozygous mutations, causing a focal, canonical DNA hypomethylation phenotype; this phenotype is partially recapitulated in murine Dnmt3a-/- bone marrow cells. To determine whether the hypomethylation phenotype of Dnmt3a-/- hematopoietic cells is reversible, we developed an inducible transgene to restore expression of DNMT3A in transplanted bone marrow cells from Dnmt3a-/- mice. Partial remethylation was detected within 1 wk, but near-complete remethylation required 6 mo. Remethylation was accurate, dynamic, and highly ordered, suggesting that differentially methylated regions have unique properties that may be relevant for their functions. Importantly, 22 wk of DNMT3A addback partially corrected dysregulated gene expression, and mitigated the expansion of myeloid cells. These data show that restoring DNMT3A expression can alter the epigenetic "state" created by loss of Dnmt3a activity; this genetic proof-of-concept experiment suggests that this approach could be relevant for patients with ARCH or AML caused by loss-of-function DNMT3A mutations.

How equestrians conceptualise horse welfare: Does it facilitate or hinder change?

More than ever the welfare of horses in equestrian sport is in the spotlight. In response to this scrutiny, one peak body, the Federation Equestre Internationale (FEI) has created an Equine Ethics and Wellbeing Commission to protect their sport's longevity. However, for welfare-based strategies to be successful, the conceptualisation of horse welfare must align across various stakeholders, including the general public. The value-laden nature of welfare makes agreement on its definition, even among scientists, difficult. Given little is known about how equestrians conceptualise horse welfare, we interviewed 19 Australian amateur equestrians using a semi-structured format. Systems thinking and the Five Domains Model provided the theoretical framework and informed our methods. Using reflexive thematic analysis, three themes were identified: (1) good horse welfare is tangible; (2) owners misinterpret unwanted horse behaviour; and (3) equestrians publicly minimise horse welfare issues but are privately concerned. Our results highlight participants' conceptualisations of horse welfare do not align with the Five Domains Model; participants' ideal of prioritising horse welfare does not align with their practice; and there is inconsistency between what participants share publicly and what they think privately about horse welfare. These findings can inform the development of programmes to improve ridden horse welfare throughout the horse industry. As a starting point, programmes that provide a safe space for equestrians to explore their private horse welfare concerns, and programmes that build a partnership mindset to facilitate knowledge exchange between all stakeholders are needed.

Bystander preference for naloxone products: a field experiment.

BACKGROUND: Bystander administration of naloxone is a critical strategy to mitigate opioid overdose mortality. To ensure bystanders' willingness to carry and administer naloxone in response to a suspected overdose, it is critical to select products for community distribution with the highest likelihood of being utilized. This study examines bystanders' preference for and willingness to administer three naloxone products approved by the FDA for bystander use and identify product features driving preference. METHODS: The population was a convenience sample of individuals who attended the Kentucky State Fair, August 18-28, 2022, in Louisville, Kentucky. Participants (n = 503) watched a standardized overdose education and naloxone training video, rated their willingness to administer each of three products (i.e., higher-dose nasal spray, lower-dose nasal spray, intramuscular injection), selected a product to take home, and rated factors affecting choice. RESULTS: After training, 44.4% chose the higher-dose nasal spray, 30.1% chose the intramuscular injection, and 25.5% chose the lower-dose nasal spray. Factors most influencing choice on a 10-point Likert scale were ease of use (9 [7-10]), naloxone dose (8 [5-10]), and product familiarity (5 [5-9]). CONCLUSIONS: Bystanders expressed high willingness to administer all studied formulations of naloxone products. Product choice preference varied as a function of product features. As the number and variety of available products continue to increase, continuous evaluation of formulation acceptability, in addition to including individuals with lived experience who are receiving and administering overdose reversal agents, is critical to support adoption and save lives.