Bitter Taste Receptor T2R14 and Autophagy Flux in Gingival Epithelial Cells.

Macroautophagy (hereafter autophagy) is a lysosomal degradation pathway that functions in nutrient recycling and as a mechanism of innate immunity. Previously, we reported a novel host-bacteria interaction between cariogenic S. mutans and bitter taste receptor (T2R14) in gingival epithelial cells (GECs), leading to an innate immune response. Further, S. mutans might be using the host immune system to inhibit other Gram-positive bacteria, such as S. aureus. To determine whether these bacteria exploit the autophagic machinery of GEC, it is first necessary to evaluate the role of T2R14 in modulating autophagic flux. So far, the role of T2R14 in the regulation of autophagy is not well characterized. Therefore, in this study, for the first time, we report that T2R14 downregulates autophagy flux in GECs, and T2R14 knockout increases acidic vacuoles. However, the treatments of GEC WT with a T2R14 agonist and antagonist did not lead to a significant change in acidic vacuole formation. Transmission electron microscopy morphometric results also suggested an increased number of autophagic vesicles in T2R14-knockout GEC. Further, our results suggest that S. mutans competence stimulating peptide CSP-1 showed robust intracellular calcium release and this effect is both T2R14- and autophagy protein 7-dependent. In this study, we provide the first evidence that T2R14 modulates autophagy flux in GEC. The results of the current study could help in identifying the impact of T2R in regulation of the immuno-microenvironment of GEC and subsequently oral health.

Effect of a Telehealth Navigator Program on Video Visit Scheduling and Completion in Primary Care.

INTRODUCTION: Patients and clinicians face challenges in participating in video telehealth visits. Patient navigation has been effective in other settings in enhancing patients' engagement with clinical programs. Our objective was to assess whether implementing a telehealth navigator program to support patients and clinicians affected video visit scheduling, video usage, and non-attendance. METHODS: This was a quasi-experimental quality improvement project using difference-in-differences. We included data from 17 adult primary care sites at a large, urban public healthcare system from October 1, 2021 to October 31, 2022. Six sites received telehealth navigators and 11 sites were used as comparators. Navigators contacted patients (by phone) with upcoming video visits to assess and address potential barriers to successful video visit completion. They also provided on-site support to patients and clinicians regarding telehealth visits and usage of an electronic patient portal. The primary outcomes were difference-in-differences for the proportion of telehealth visits scheduled and, separately, completed as video visits and non-attendance for visits scheduled as video visits. RESULTS: There were 65 488 and 71 504 scheduled telehealth appointments at intervention and non-intervention sites, respectively. The adjusted difference-in-differences for the proportion of telehealth visits scheduled as video was -9.1% [95% confidence interval -26.1%, 8.0%], the proportion of telehealth visits completed as video visits 1.3% [-4.9%, 7.4%], and non-attendance for visits scheduled as video visits -3.7% [-6.0%, -1.4%]. CONCLUSIONS: Sites with telehealth navigators had comparatively lower video visit non-attendance but did not have comparatively different video visit scheduling or completion rates. Despite this, navigators' on-the-ground presence can help identify opportunities for improvements in care design.

Relative billing complexity of in-person versus telehealth outpatient encounters.

RATIONALE: Video visits became more widely available during the coronavirus disease (COVID-19) pandemic. However, the ongoing role and value of video visits in care delivery and how these may have changed over time are not well understood. AIMS AND OBJECTIVES: Compare the relative complexity of in-person versus video visits during the COVID-19 pandemic and describe the complexity of video visits over time. METHODS: We used billing data for in-person and video revisits from non-behavioural health specialities with the most video visit utilisation (≥50th percentile) at a large, urban, public healthcare system from 1 January 2021 to 31 March 2022. We used current procedural terminology (CPT) codes as a proxy for information gathering and decision-making complexity and time spent on an encounter. We compared the distribution of CPT codes 99211-99215 between in-person and video visits using Fisher's exact tests. We used Spearman correlation to test for trends between proportions of CPT codes over time for video visits. RESULTS: Ten specialities (adult primary care, paediatrics, adult dermatology, bariatric surgery, paediatric endocrinology, obstetrics and gynaecologist, adult haematology/oncology, paediatric allergy/immunology, paediatric gastroenterology, and paediatric pulmonology) met inclusion criteria. For each speciality, proportions of each CPT code for in-person visits and for video visits varied significantly, and patterns of variation differed by speciality. For example, in adult primary care, video visits had smaller proportions of moderate/high complexity visits (99214 and 99215) and greater proportions of lower complexity visits (99211-99213) compared with in-person visits (p < 0.001), but in paediatric endocrinology, the opposite was seen (p < 0.001). Trends in CPT codes over time for video visits in each speciality were also mixed. CONCLUSION: In-person and video visits had differing proportions of complexity codes (typically skewing towards lower complexity for video visits). The complexity of video visits changed over time in many specialities. Observed patterns for both phenomena varied by speciality.

Patient Characteristics Associated with Telehealth Scheduling and Completion in Primary Care at a Large, Urban Public Healthcare System.

Understanding patient characteristics associated with scheduling and completing telehealth visits can identify potential biases or latent preferences related to telehealth usage. We describe patient characteristics associated with being scheduled for and completing audio and video visits. We used data from patients at 17 adult primary care departments in a large, urban public healthcare system from August 1, 2020 to July 31, 2021. We used hierarchical multivariable logistic regression to generate adjusted odds ratios (aOR) for patient characteristics associated with having been scheduled for and completed telehealth (vs in-person) visits and for video (vs audio) scheduling and completion during two time periods: a telehealth transition period (N = 190,949) and a telehealth elective period (N = 181,808). Patient characteristics were significantly associated with scheduling and completion of telehealth visits. Many associations were similar across time periods, but others changed over time. Patients who were older (≥ 65 years old vs 18-44 years old: aOR for scheduling 0.53/completion 0.48), Black (0.86/0.71), Hispanic (0.76/0.62), or had Medicaid (0.93/0.84) were among those less likely to be scheduled for or complete video (vs audio) visits. Patients with activated patient portals (1.97/3.34) or more visits (≥ 3 scheduled visits vs 1 visit: 2.40/1.52) were more likely to be scheduled for or complete video visits. Variation in scheduling/completion explained by patient characteristics was 7.2%/7.5%, clustering by provider 37.2%/34.9%, and clustering by facility 43.1%/37.4%. Stable and dynamic associations suggest persistent gaps in access and evolving preferences/biases. Variation explained by patient characteristics was relatively low compared with that explained by provider and facility clustering.

KDM6B protects T-ALL cells from NOTCH1-induced oncogenic stress.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematopoietic neoplasm resulting from the malignant transformation of T-cell progenitors. While activating NOTCH1 mutations are the dominant genetic drivers of T-ALL, epigenetic dysfunction plays a central role in the pathology of T-ALL and can provide alternative mechanisms to oncogenesis in lieu of or in combination with genetic mutations. The histone demethylase enzyme KDM6A (UTX) is also recurrently mutated in T-ALL patients and functions as a tumor suppressor. However, its gene paralog, KDM6B (JMJD3), is never mutated and can be significantly overexpressed, suggesting it may be necessary for sustaining the disease. Here, we used mouse and human T-ALL models to show that KDM6B is required for T-ALL development and maintenance. Using NOTCH1 gain-of-function retroviral models, mouse cells genetically deficient for Kdm6b were unable to propagate T-ALL. Inactivating KDM6B in human T-ALL patient cells by CRISPR/Cas9 showed KDM6B-targeted cells were significantly outcompeted over time. The dependence of T-ALL cells on KDM6B was proportional to the oncogenic strength of NOTCH1 mutation, with KDM6B required to prevent stress-induced apoptosis from strong NOTCH1 signaling. These studies identify a crucial role for KDM6B in sustaining NOTCH1-driven T-ALL and implicate KDM6B as a novel therapeutic target in these patients.

Appointment Non-attendance for Telehealth Versus In-Person Primary Care Visits at a Large Public Healthcare System.

BACKGROUND: Appointment non-attendance has clinical, operational, and financial implications for patients and health systems. How telehealth services are associated with non-attendance in primary care is not well-described, nor are patient characteristics associated with telehealth non-attendance. OBJECTIVE: We sought to compare primary care non-attendance for telehealth versus in-person visits and describe patient characteristics associated with telehealth non-attendance. DESIGN: An observational study of electronic health record data. PARTICIPANTS: Patients with primary care encounters at 23 adult primary care clinics at a large, urban public healthcare system from November 1, 2019, to August 31, 2021. MAIN MEASURES: We analyzed non-attendance by modality (telephone, video, in-person) during three time periods representing different availability of telehealth using hierarchal multiple logistic regression to control for patient demographics and variation within patients and clinics. We stratified by modality and used hierarchal multiple logistic regression to assess for associations between patient characteristics and non-attendance in each modality. KEY RESULTS: There were 1,219,781 scheduled adult primary care visits by 329,461 unique patients: 754,149 (61.8%) in-person, 439,295 (36.0%) telephonic, and 26,337 (2.2%) video visits. Non-attendance for telephone visits was initially higher than that for in-person visits (adjusted odds ratio 1.04 [95% CI 1.02, 1.07]) during the early telehealth availability period, but decreased later (0.82 [0.81, 0.83]). Non-attendance for video visits was higher than for in-person visits during the early (4.37 [2.74, 6.97]) and later (2.02 [1.95, 2.08]) periods. Telephone visits had fewer differences in non-attendance by demographics; video visits were associated with increased non-attendance for patients who were older, male, had a primary language other than English or Spanish, and had public or no insurance. CONCLUSIONS: Telephonic visits may improve access to care and be more easily adoptable among diverse populations. Further attention to implementation may be needed to avoid impeding access to care for certain populations using video visits.

Primary care utilization among telehealth users and non-users at a large urban public healthcare system.

Telehealth services may improve access to care, but there are concerns around whether availability of telehealth may increase care utilization. We assessed whether usage of telehealth was associated with differential primary care utilization at a large, urban public healthcare system. Using electronic health record data from 23 primary care clinics, we categorized patients as telehealth users and non-users. Then, we compared the number of visits per patient between groups using Welch's t-tests while stratifying by comorbidity count. We used multivariable Poisson regression to test for associations between telehealth usage and visit count while controlling for other demographic factors. Compared with telehealth non-users, telehealth users had approximately 1 more primary care visit per patient over the year regardless of comorbidity count or other patient characteristics. Availability of telehealth services may be associated with increased primary care utilization in a safety-net setting, though further research on outcomes, costs of care, and patient and clinician experiences is needed to better inform decisions regarding provision and reimbursement of telehealth services.

Increased frequency of TIGIT+ CD4 T Cell subset in autoantibody-positive first-degree relatives of patients with rheumatoid arthritis.

Background: Despite immune cell dysregulation being an important event preceding the onset of rheumatoid arthritis (RA), the phenotype of T and B cells in preclinical RA is less understood. The aim of this study was to characterize T and B cell populations in RA patients and their autoantibody (aAb) negative and positive first-degree relatives (FDR). Methods: Cryopreserved peripheral blood mononuclear cells (PBMCs) collected at scheduled visits from aAb-(n=25), and aAb+ FDR (n=10) and RA patients (n=13) were thawed and stained using optimized antibody cocktails as per a specific 13-color T or B cell panel. Immunophenotyping was performed using a Cytoflex LX (Beckman-Coulter) flow cytometer and FlowJo software was used for analyzing the frequency of immune cell populations. Results: Multicolor flow cytometry experiments identified an increased TIGIT expression in circulating lymphocytes of aAb+ FDR and RA patients, relative to aAb- FDR (P<0.01). These TIGIT+ T cells exhibited a memory phenotype and expressed high levels of PD-1, ICOS, HLA-DR, CXCR3 and CXCR5. Moreover, increased TIGIT+ CD4 T cell frequency correlated with the frequency of PD-1+ CD4 T cells (r = 0.4705: P = 0.0043) and circulating levels of ACPA and RF. We also identified a decreased frequency of CD27+IgD- switched memory B cells in RA patients (P < 0.01), while increased frequency of TIGIT+ CD4 T cells in FDR correlated with the frequency of PD1+PTEN+ B cells (r = 0.6838, P = 0.0004) and autoantibody positivity (P = 0.01). Conclusion: We demonstrate TIGIT as a distinct CD4 T cell marker for differentiating aAb- FDR from aAb+FDR and might play a critical role in regulating T and B cell crosstalk in preclinical RA.

SARS-CoV-2 impairs interferon production via NSP2-induced repression of mRNA translation.

Viruses evade the innate immune response by suppressing the production or activity of cytokines such as type I interferons (IFNs). Here we report the discovery of a mechanism by which the SARS-CoV-2 virus coopts an intrinsic cellular machinery to suppress the production of the key immunostimulatory cytokine IFN-ß. We reveal that the SARS-CoV-2 encoded nonstructural protein 2 (NSP2) directly interacts with the cellular GIGYF2 protein. This interaction enhances the binding of GIGYF2 to the mRNA cap-binding protein 4EHP, thereby repressing the translation of the Ifnb1 mRNA. Depletion of GIGYF2 or 4EHP significantly enhances IFN-ß production, which inhibits SARS-CoV-2 replication. Our findings reveal a target for rescuing the antiviral innate immune response to SARS-CoV-2 and other RNA viruses.

Txnip Enhances Fitness of Dnmt3a-Mutant Hematopoietic Stem Cells via p21.

Clonal hematopoiesis (CH) refers to the age-related expansion of specific clones in the blood system, and manifests from somatic mutations acquired in hematopoietic stem cells (HSCs). Most CH variants occur in the gene DNMT3A, but while DNMT3A-mutant CH becomes almost ubiquitous in aging humans, a unifying molecular mechanism to illuminate how DNMT3A-mutant HSCs outcompete their counterparts is lacking. Here, we used interferon gamma (IFNγ) as a model to study the mechanisms by which Dnmt3a mutations increase HSC fitness under hematopoietic stress. We found Dnmt3a-mutant HSCs resist IFNγ-mediated depletion, and IFNγ-signaling is required for clonal expansion of Dnmt3a-mutant HSCs in vivo. Mechanistically, DNA hypomethylation-associated overexpression of Txnip in Dnmt3a-mutant HSCs leads to p53 stabilization and upregulation of p21. This preserves the functional potential of Dnmt3a-mutant HSCs through increased quiescence and resistance to IFNγ-induced apoptosis. These data identify a previously undescribed mechanism to explain increased fitness of DNMT3A-mutant clones under hematopoietic stress. SIGNIFICANCE: DNMT3A mutations are common variants in clonal hematopoiesis, and recurrent events in blood cancers. Yet the mechanisms by which these mutations provide hematopoietic stem cells a competitive advantage as a precursor to malignant transformation remain unclear. Here, we use inflammatory stress to uncover molecular mechanisms leading to this fitness advantage.See related commentary by De Dominici and DeGregori, p. 178. This article is highlighted in the In This Issue feature, p. 171.

A Humanized Animal Model Predicts Clonal Evolution and Therapeutic Vulnerabilities in Myeloproliferative Neoplasms.

Myeloproliferative neoplasms (MPN) are chronic blood diseases with significant morbidity and mortality. Although sequencing studies have elucidated the genetic mutations that drive these diseases, MPNs remain largely incurable with a significant proportion of patients progressing to rapidly fatal secondary acute myeloid leukemia (sAML). Therapeutic discovery has been hampered by the inability of genetically engineered mouse models to generate key human pathologies such as bone marrow fibrosis. To circumvent these limitations, here we present a humanized animal model of myelofibrosis (MF) patient-derived xenografts (PDX). These PDXs robustly engrafted patient cells that recapitulated the patient's genetic hierarchy and pathologies such as reticulin fibrosis and propagation of MPN-initiating stem cells. The model can select for engraftment of rare leukemic subclones to identify patients with MF at risk for sAML transformation and can be used as a platform for genetic target validation and therapeutic discovery. We present a novel but generalizable model to study human MPN biology. SIGNIFICANCE: Although the genetic events driving MPNs are well defined, therapeutic discovery has been hampered by the inability of murine models to replicate key patient pathologies. Here, we present a PDX system to model human myelofibrosis that reproduces human pathologies and is amenable to genetic and pharmacologic manipulation. This article is highlighted in the In This Issue feature, p. 2945.

Altered T Follicular Helper Cell Subsets and Function in Chronic Lymphocytic Leukemia.

Follicular helper T cells (TFH) have specialized properties in promoting normal B cell activation but their role in chronic lymphocytic leukemia (CLL) is unknown. We find that TFH cells are elevated in CLL patients and are phenotypically abnormal, expressing higher levels of PD-1, TIGIT, CD40L, IFNγ and IL-21, and exhibiting abnormal composition of TFH1, TFH2 and TFH17 subsets. Frequencies of CD4-positive T cells expressing TFH1 markers and IL-21 were positively correlated with patient lymphocyte counts and RAI stage, suggesting that accumulation of abnormal TFH cells is concomitant with expansion of the leukemic B cell clone. Treatment with ibrutinib led to normalization of TFH frequencies and phenotype. TFH cells identified in CLL bone marrow display elevated expression of several functional markers compared to blood TFH cells. CLL T cell-B cell co-culture experiments revealed a correlation of patient TFH frequencies with functional ability of their CD4-positive T cells to promote CLL proliferation. Conversely, CLL cells can preferentially activate the TFH cell subset in co-culture. Together our results indicate that CLL development is associated with expansion of abnormal TFH populations that produce elevated levels of cytokines and costimulatory molecules which may help support CLL proliferation.

Dietary Macronutrient Composition Differentially Modulates the Remodeling of Mitochondrial Oxidative Metabolism during NAFLD.

Diets rich in fats and carbohydrates aggravate non-alcoholic fatty liver disease (NAFLD), of which mitochondrial dysfunction is a central feature. It is not clear whether a high-carbohydrate driven 'lipogenic' diet differentially affects mitochondrial oxidative remodeling compared to a high-fat driven 'oxidative' environment. We hypothesized that the high-fat driven 'oxidative' environment will chronically sustain mitochondrial oxidative function, hastening metabolic dysfunction during NAFLD. Mice (C57BL/6NJ) were reared on a low-fat (LF; 10% fat calories), high-fat (HF; 60% fat calories), or high-fructose/high-fat (HFr/HF; 25% fat and 34.9% fructose calories) diet for 10 weeks. De novo lipogenesis was determined by measuring the incorporation of deuterium from D2O into newly synthesized liver lipids using nuclear magnetic resonance (NMR) spectroscopy. Hepatic mitochondrial metabolism was profiled under fed and fasted states by the incubation of isolated mitochondria with [13C3]pyruvate, targeted metabolomics of tricarboxylic acid (TCA) cycle intermediates, estimates of oxidative phosphorylation (OXPHOS), and hepatic gene and protein expression. De novo lipogenesis was higher in the HFr/HF mice compared to their HF counterparts. Contrary to our expectations, hepatic oxidative function after fasting was induced in the HFr/HF group. This differential induction of mitochondrial oxidative function by the high fructose-driven 'lipogenic' environment could influence the progressive severity of hepatic insulin resistance.

Branched chain amino acids and carbohydrate restriction exacerbate ketogenesis and hepatic mitochondrial oxidative dysfunction during NAFLD.

Mitochondrial adaptation during non-alcoholic fatty liver disease (NAFLD) include remodeling of ketogenic flux and sustained tricarboxylic acid (TCA) cycle activity, which are concurrent to onset of oxidative stress. Over 70% of obese humans have NAFLD and ketogenic diets are common weight loss strategies. However, the effectiveness of ketogenic diets toward alleviating NAFLD remains unclear. We hypothesized that chronic ketogenesis will worsen metabolic dysfunction and oxidative stress during NAFLD. Mice (C57BL/6) were kept (for 16-wks) on either a low-fat, high-fat, or high-fat diet supplemented with 1.5X branched chain amino acids (BCAAs) by replacing carbohydrate calories (ketogenic). The ketogenic diet induced hepatic lipid oxidation and ketogenesis, and produced multifaceted changes in flux through the individual steps of the TCA cycle. Higher rates of hepatic oxidative fluxes fueled by the ketogenic diet paralleled lower rates of de novo lipogenesis. Interestingly, this metabolic remodeling did not improve insulin resistance, but induced fibrogenic genes and inflammation in the liver. Under a chronic "ketogenic environment," the hepatocyte diverted more acetyl-CoA away from lipogenesis toward ketogenesis and TCA cycle, a milieu which can hasten oxidative stress and inflammation. In summary, chronic exposure to ketogenic environment during obesity and NAFLD has the potential to aggravate hepatic mitochondrial dysfunction.

Alien hand syndrome - a rare presentation of stroke.

Alien Hand Syndrome (AHS) is characterized by intermittent and involuntary movements of a single limb that is not associated with motor dysfunction. AHS may be the initial presentation of serious underlying pathology, such as stroke localized to the non-dominant parietal lobe, corpus callosum damage, or neurodegenerative disease. AHS occurs at a low prevalence in the general population yet represents significant underlying disease burden, necessitating early identification. In this case report, we present an 88-year-old right-handed male with involuntary movement of his left forearm and hand three hours prior to presentation. His symptom corresponded to findings on MRI of the brain, which showed acute infarcts of the right temporal lobe, right parietal cortex, and right parietal subcortex. Infarction of the right parietal cortex accounted for his AHS. The multifocal nature of the infarcts elevated the index of suspicion for an embolic source.

Low FoxO expression in Drosophila somatosensory neurons protects dendrite growth under nutrient restriction.

During prolonged nutrient restriction, developing animals redistribute vital nutrients to favor brain growth at the expense of other organs. In Drosophila, such brain sparing relies on a glia-derived growth factor to sustain proliferation of neural stem cells. However, whether other aspects of neural development are also spared under nutrient restriction is unknown. Here we show that dynamically growing somatosensory neurons in the Drosophila peripheral nervous system exhibit organ sparing at the level of arbor growth: Under nutrient stress, sensory dendrites preferentially grow as compared to neighboring non-neural tissues, resulting in dendrite overgrowth. These neurons express lower levels of the stress sensor FoxO than neighboring epidermal cells, and hence exhibit no marked induction of autophagy and a milder suppression of Tor signaling under nutrient stress. Preferential dendrite growth allows for heightened animal responses to sensory stimuli, indicative of a potential survival advantage under environmental challenges.

The organs of a young animal develop in a carefully controlled way to reach the right size relative to each other. However, if the animal's diet does not contain the right amount of nutrients ­ a condition known as malnutrition ­ the body prioritizes the needs of the brain and other vital organs. This means that certain organs keep on growing while others stop. The brain is at the center of the nervous system, which is formed of networks of nerve cells (or neurons) that rapidly carry messages around the body. In the larvae of malnourished fruit flies, a molecular signal allows the nervous system to continue making new neurons as other parts of the body slow down their growth. During development, neurons also connect to each other by growing tree-like structures known as dendrites. However, it remained unclear whether the growth of dendrites was also protected during episodes of malnutrition. To address this question, Poe, Xu et al. performed experiments in the larvae of fruit flies, focusing on a type of neuron whose dendrites extend into the skin. When nutrients were scarce, the neurons grew more rapidly than the surrounding skin cells, resulting in dendrite overgrowth. Compared to neurons, the skin cells had higher levels of a stress sensor known as FoxO, which stops cell growth when nutrients are scarce. Conversely, low quantities of FoxO in neurons allow these cells to keep on growing dendrites, which ultimately helps the starved animals to better react to their environment. These results suggest that the growth of neurons and their connecting structures is preserved during malnutrition. Ultimately, dissecting how organisms prioritize resources can help to develop new approaches to treat human conditions that emerge during malnutrition.

The Effects of Age, Distraction, and Simulated Central Vision Impairment on Hazard Detection in a Driving Simulator.

SIGNIFICANCE: Despite similar levels of visual acuity and contrast sensitivity reductions, simulated central vision impairment increased response times to a much greater extent in older than in younger participants. PURPOSE: Driving is crucial for maintaining independence in older age, but age-related vision impairments and in-vehicle auditory distractions may impair driving safety. We investigated the effects of age, simulated central vision impairment, and auditory distraction on detection of pedestrian hazards. METHODS: Thirty-two normally sighted participants (16 younger and 16 older) completed four highway drives in a simulator and pressed the horn whenever they saw a pedestrian. Pedestrians ran toward the road on a collision course with the approaching vehicle. Simulated central vision impairment was achieved by attaching diffusing filters to a pair of laboratory goggles, which reduced visual acuity to 20/80 and contrast sensitivity by 0.35 log units. For drives with distraction, subjects listened to an audiobook and repeated out loud target words. RESULTS: Simulated central vision impairment had a greater effect on reaction times (660-millisecond increase) than age (350-millisecond increase) and distraction (160-millisecond increase) and had a greater effect on older than younger subjects (828- and 492-millisecond increase, respectively). Simulated central vision impairment decreased safe response rates from 94.7 to 78.3%. Distraction did not, however, affect safety because older subjects drove more slowly when distracted (but did not drive more slowly with vision impairment), suggesting that they might have perceived greater threat from the auditory distraction than the vision impairment. CONCLUSIONS: Older participants drove more slowly in response to auditory distraction. However, neither older nor younger participants adapted their speed in response to simulated vision impairment, resulting in unsafe detections. These results underline the importance of evaluating safety of responses to hazards as well as reaction times in a paradigm that flexibly allows participants to modify their driving behaviors.

Divergent Effects of Dnmt3a and Tet2 Mutations on Hematopoietic Progenitor Cell Fitness.

The DNA methylation regulators DNMT3A and TET2 are recurrently mutated in hematological disorders. Despite possessing antagonistic biochemical activities, loss-of-function murine models show overlapping phenotypes in terms of increased hematopoietic stem cell (HSC) fitness. Here, we directly compared the effects of these mutations on hematopoietic progenitor function and disease initiation. In contrast to Dnmt3a-null HSCs, which possess limitless self-renewal in vivo, Tet2-null HSCs unexpectedly exhaust at the same rate as control HSCs in serial transplantation assays despite an initial increase in self-renewal. Moreover, loss of Tet2 more acutely sensitizes hematopoietic cells to the addition of a common co-operating mutation (Flt3ITD) than loss of Dnmt3a, which is associated with a more rapid expansion of committed progenitor cells. The effect of Tet2 mutation manifests more profound myeloid lineage skewing in committed hematopoietic progenitor cells rather than long-term HSCs. Molecular characterization revealed divergent transcriptomes and chromatin accessibility underlying these functional differences.

Erratum: PTEN deletion drives acute myeloid leukemia resistance to MEK inhibitors.

[This corrects the article DOI: 10.18632/oncotarget.27206.].