Distinct Mesenchymal Lineages and Niches Promote Epithelial Self-Renewal and Myofibrogenesis in the Lung.

The lung is an architecturally complex organ comprising a heterogeneous mixture of various epithelial and mesenchymal lineages. We use single-cell RNA sequencing and signaling lineage reporters to generate a spatial and transcriptional map of the lung mesenchyme. We find that each mesenchymal lineage has a distinct spatial address and transcriptional profile leading to unique niche regulatory functions. The mesenchymal alveolar niche cell is Wnt responsive, expresses Pdgfrα, and is critical for alveolar epithelial cell growth and self-renewal. In contrast, the Axin2+ myofibrogenic progenitor cell preferentially generates pathologically deleterious myofibroblasts after injury. Analysis of the secretome and receptome of the alveolar niche reveals functional pathways that mediate growth and self-renewal of alveolar type 2 progenitor cells, including IL-6/Stat3, Bmp, and Fgf signaling. These studies define the cellular and molecular framework of lung mesenchymal niches and reveal the functional importance of developmental pathways in promoting self-renewal versus a pathological response to tissue injury.

The genomic basis of childhood T-lineage acute lymphoblastic leukaemia.

T-lineage acute lymphoblastic leukaemia (T-ALL) is a high-risk tumour1 that has eluded comprehensive genomic characterization, which is partly due to the high frequency of noncoding genomic alterations that result in oncogene deregulation2,3. Here we report an integrated analysis of genome and transcriptome sequencing of tumour and remission samples from more than 1,300 uniformly treated children with T-ALL, coupled with epigenomic and single-cell analyses of malignant and normal T cell precursors. This approach identified 15 subtypes with distinct genomic drivers, gene expression patterns, developmental states and outcomes. Analyses of chromatin topology revealed multiple mechanisms of enhancer deregulation that involve enhancers and genes in a subtype-specific manner, thereby demonstrating widespread involvement of the noncoding genome. We show that the immunophenotypically described, high-risk entity of early T cell precursor ALL is superseded by a broader category of 'early T cell precursor-like' leukaemia. This category has a variable immunophenotype and diverse genomic alterations of a core set of genes that encode regulators of hematopoietic stem cell development. Using multivariable outcome models, we show that genetic subtypes, driver and concomitant genetic alterations independently predict treatment failure and survival. These findings provide a roadmap for the classification, risk stratification and mechanistic understanding of this disease.

Fennoscandian tree-ring anatomy shows a warmer modern than medieval climate.

Earth system models and various climate proxy sources indicate global warming is unprecedented during at least the Common Era1. However, tree-ring proxies often estimate temperatures during the Medieval Climate Anomaly (950-1250 CE) that are similar to, or exceed, those recorded for the past century2,3, in contrast to simulation experiments at regional scales4. This not only calls into question the reliability of models and proxies but also contributes to uncertainty in future climate projections5. Here we show that the current climate of the Fennoscandian Peninsula is substantially warmer than that of the medieval period. This highlights the dominant role of anthropogenic forcing in climate warming even at the regional scale, thereby reconciling inconsistencies between reconstructions and model simulations. We used an annually resolved 1,170-year-long tree-ring record that relies exclusively on tracheid anatomical measurements from Pinus sylvestris trees, providing high-fidelity measurements of instrumental temperature variability during the warm season. We therefore call for the construction of more such millennia-long records to further improve our understanding and reduce uncertainties around historical and future climate change at inter-regional and eventually global scales.

Dynamic Hippo pathway activity underlies mesenchymal differentiation during lung alveolar morphogenesis.

Alveologenesis, the final stage in lung development, substantially remodels the distal lung, expanding the alveolar surface area for efficient gas exchange. Secondary crest myofibroblasts (SCMF) exist transiently in the neonatal distal lung and are crucial for alveologenesis. However, the pathways that regulate SCMF function, proliferation and temporal identity remain poorly understood. To address this, we purified SCMFs from reporter mice, performed bulk RNA-seq and found dynamic changes in Hippo-signaling components during alveologenesis. We deleted the Hippo effectors Yap/Taz from Acta2-expressing cells at the onset of alveologenesis, causing a significant arrest in alveolar development. Using single cell RNA-seq, we identified a distinct cluster of cells in mutant lungs with altered expression of marker genes associated with proximal mesenchymal cell types, airway smooth muscle and alveolar duct myofibroblasts. In vitro studies confirmed that Yap/Taz regulates myofibroblast-associated gene signature and contractility. Together, our findings show that Yap/Taz is essential for maintaining functional myofibroblast identity during postnatal alveologenesis.

Retraction Note: Fatty acids and cancer-amplified ZDHHC19 promote STAT3 activation through S-palmitoylation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

CXCL12 defines lung endothelial heterogeneity and promotes distal vascular growth.

There is a growing amount of data uncovering the cellular diversity of the pulmonary circulation and mechanisms governing vascular repair after injury. However, the molecular and cellular mechanisms contributing to the morphogenesis and growth of the pulmonary vasculature during embryonic development are less clear. Importantly, deficits in vascular development lead to significant pediatric lung diseases, indicating a need to uncover fetal programs promoting vascular growth. To address this, we used a transgenic mouse reporter for expression of Cxcl12, an arterial endothelial hallmark gene, and performed single-cell RNA sequencing on isolated Cxcl12-DsRed+ endothelium to assess cellular heterogeneity within pulmonary endothelium. Combining cell annotation with gene ontology and histological analysis allowed us to segregate the developing artery endothelium into functionally and spatially distinct subpopulations. Expression of Cxcl12 is highest in the distal arterial endothelial subpopulation, a compartment enriched in genes for vascular development. Accordingly, disruption of CXCL12 signaling led to, not only abnormal branching, but also distal vascular hypoplasia. These data provide evidence for arterial endothelial functional heterogeneity and reveal conserved signaling mechanisms essential for pulmonary vascular development.

Fatty acids and cancer-amplified ZDHHC19 promote STAT3 activation through S-palmitoylation.

Signal transducer and activator of transcription 3 (STAT3) has a critical role in regulating cell fate, inflammation and immunity1,2. Cytokines and growth factors activate STAT3 through kinase-mediated tyrosine phosphorylation and dimerization3,4. It remains unknown whether other factors promote STAT3 activation through different mechanisms. Here we show that STAT3 is post-translationally S-palmitoylated at the SRC homology 2 (SH2) domain, which promotes the dimerization and transcriptional activation of STAT3. Fatty acids can directly activate STAT3 by enhancing its palmitoylation, in synergy with cytokine stimulation. We further identified ZDHHC19 as a palmitoyl acyltransferase that regulates STAT3. Cytokine stimulation increases STAT3 palmitoylation by promoting the association between ZDHHC19 and STAT3, which is mediated by the SH3 domain of GRB2. Silencing ZDHHC19 blocks STAT3 palmitoylation and dimerization, and impairs the cytokine- and fatty-acid-induced activation of STAT3. ZDHHC19 is frequently amplified in multiple human cancers, including in 39% of lung squamous cell carcinomas. High levels of ZDHHC19 correlate with high levels of nuclear STAT3 in patient samples. In addition, knockout of ZDHHC19 in lung squamous cell carcinoma cells significantly blocks STAT3 activity, and inhibits the fatty-acid-induced formation of tumour spheres as well as tumorigenesis induced by high-fat diets in an in vivo mouse model. Our studies reveal that fatty-acid- and ZDHHC19-mediated palmitoylation are signals that regulate STAT3, which provides evidence linking the deregulation of palmitoylation to inflammation and cancer.

Chronic Hypoxia in an EXTrauterine Environment for Neonatal Development Impairs Lung Development.

Severe fetal hypoxia poses a significant risk to lung development resulting in severe postnatal complications. Existing chronic hypoxia animal models lack the ability to achieve pathologically reduced fetal oxygen without compromising animal development, placental blood flow, or maternal health. Using an established model of isolated chronic hypoxia involving the Extrauterine Environment for Neonatal Development (EXTEND), we are able to investigate the direct impact of fetal hypoxia on lung development. Oxygen delivery to preterm fetal lambs (105-110 days GA) delivered by cesarean section was reduced, and animals were supported on EXTEND through the canalicular or saccular stage of lung development. Fetal lambs in hypoxic conditions showed significant growth restriction compared to their normoxic counterparts. We also observed modest aberrant vascular remodeling in the saccular group after hypoxic conditions with decreased macrovessel numbers, microvascular endothelial cell numbers, and increased peripheral vessel muscularization. In addition, fetal hypoxia resulted in enlarged distal airspaces and decreased septal wall volume. Moreover, there was a reduction in mature SFTPB and processed SFTPC protein expression concomitant with a decrease in AT2 cell number. These findings demonstrate that maternally-independent fetal hypoxia predominantly impacts distal airway development, AT2 cell number, and surfactant production with mild effects on the vasculature.

Correction: Oncogenic Transformation by Inhibitor-Sensitive and -Resistant EGFR Mutants.

[This corrects the article DOI: 10.1371/journal.pmed.0020313.].

Regeneration of the lung alveolus by an evolutionarily conserved epithelial progenitor.

Functional tissue regeneration is required for the restoration of normal organ homeostasis after severe injury. Some organs, such as the intestine, harbour active stem cells throughout homeostasis and regeneration; more quiescent organs, such as the lung, often contain facultative progenitor cells that are recruited after injury to participate in regeneration. Here we show that a Wnt-responsive alveolar epithelial progenitor (AEP) lineage within the alveolar type 2 cell population acts as a major facultative progenitor cell in the distal lung. AEPs are a stable lineage during alveolar homeostasis but expand rapidly to regenerate a large proportion of the alveolar epithelium after acute lung injury. AEPs exhibit a distinct transcriptome, epigenome and functional phenotype and respond specifically to Wnt and Fgf signalling. In contrast to other proposed lung progenitor cells, human AEPs can be directly isolated by expression of the conserved cell surface marker TM4SF1, and act as functional human alveolar epithelial progenitor cells in 3D organoids. Our results identify the AEP lineage as an evolutionarily conserved alveolar progenitor that represents a new target for human lung regeneration strategies.

Single Cell Multiomics Identifies Cells and Genetic Networks Underlying Alveolar Capillary Dysplasia.

Rationale: Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a lethal developmental disorder of lung morphogenesis caused by insufficiency of FOXF1 (forkhead box F1) transcription factor function. The cellular and transcriptional mechanisms by which FOXF1 deficiency disrupts human lung formation are unknown. Objectives: To identify cell types, gene networks, and cell-cell interactions underlying the pathogenesis of ACDMPV. Methods: We used single-nucleus RNA and assay for transposase-accessible chromatin sequencing, immunofluorescence confocal microscopy, and RNA in situ hybridization to identify cell types and molecular networks influenced by FOXF1 in ACDMPV lungs. Measurements and Main Results: Pathogenic single-nucleotide variants and copy-number variant deletions involving the FOXF1 gene locus in all subjects with ACDMPV (n = 6) were accompanied by marked changes in lung structure, including deficient alveolar development and a paucity of pulmonary microvasculature. Single-nucleus RNA and assay for transposase-accessible chromatin sequencing identified alterations in cell number and gene expression in endothelial cells (ECs), pericytes, fibroblasts, and epithelial cells in ACDMPV lungs. Distinct cell-autonomous roles for FOXF1 in capillary ECs and pericytes were identified. Pathogenic variants involving the FOXF1 gene locus disrupt gene expression in EC progenitors, inhibiting the differentiation or survival of capillary 2 ECs and cell-cell interactions necessary for both pulmonary vasculogenesis and alveolar type 1 cell differentiation. Loss of the pulmonary microvasculature was associated with increased VEGFA (vascular endothelial growth factor A) signaling and marked expansion of systemic bronchial ECs expressing COL15A1 (collagen type XV α 1 chain). Conclusions: Distinct FOXF1 gene regulatory networks were identified in subsets of pulmonary endothelial and fibroblast progenitors, providing both cellular and molecular targets for the development of therapies for ACDMPV and other diffuse lung diseases of infancy.

A longitudinal investigation of breastfeeding planning, initiation, and duration among individuals with pre-pregnancy overweight or obesity.

Individuals with a body mass index (BMI)≥25 kg/m2 are less likely to initiate and continue breastfeeding than are those with BMIs<25. Given the intergenerational health benefits of breastfeeding, it is important to understand breastfeeding behaviors and their correlates among individuals with BMIs≥25. Thus, in an observational cohort with BMI≥25 (N = 237), we aimed to characterize longitudinal relationships among breastfeeding planning, initiation, and duration and their sociodemographic/clinical correlates and determine if pre-pregnancy BMI predicts breastfeeding planning, initiation, and duration. Breastfeeding behaviors, weight/BMI, and sociodemographic/clinical characteristics were assessed in early, mid, and late pregnancy, and at six-months postpartum. Most participants planned to (84%) and initiated (81%) breastfeeding, of which 37% breastfed for ≥6 months. Participants who were married, first-time parents, higher in education/income, and had never smoked tobacco were more likely to plan, initiate, and achieve ≥6 months of breastfeeding. Higher pre-pregnancy BMI was not associated with breastfeeding planning or initiation but was associated with lower adjusted odds of breastfeeding for ≥6 months relative to <6 months. Findings suggest that support aimed at extending breastfeeding among those with elevated pre-pregnancy BMI may be warranted. Future interventions should also address sociodemographic and clinical inequities in breastfeeding.

Disparities in Guideline-Recommended Statin Use for Prevention of Atherosclerotic Cardiovascular Disease by Race, Ethnicity, and Gender : A Nationally Representative Cross-Sectional Analysis of Adults in the United States.

BACKGROUND: Although statins are a class I recommendation for prevention of atherosclerotic cardiovascular disease and its complications, their use is suboptimal. Differential underuse may mediate disparities in cardiovascular health for systematically marginalized persons. OBJECTIVE: To estimate disparities in statin use by race-ethnicity-gender and to determine whether these potential disparities are explained by medical appropriateness of therapy and structural factors. DESIGN: Cross-sectional analysis. SETTING: National Health and Nutrition Examination Survey from 2015 to 2020. PARTICIPANTS: Persons eligible for statin therapy based on 2013 and 2018 American College of Cardiology/American Heart Association blood cholesterol guidelines. MEASUREMENTS: The independent variable was race-ethnicity-gender. The outcome of interest was use of a statin. Using the Institute of Medicine framework for examining unequal treatment, we calculated adjusted prevalence ratios (aPRs) to estimate disparities in statin use adjusted for age, disease severity, access to health care, and socioeconomic status relative to non-Hispanic White men. RESULTS: For primary prevention, we identified a lower prevalence of statin use that was not explained by measurable differences in disease severity or structural factors among non-Hispanic Black men (aPR, 0.73 [95% CI, 0.59 to 0.88]) and non-Mexican Hispanic women (aPR, 0.74 [CI, 0.53 to 0.95]). For secondary prevention, we identified a lower prevalence of statin use that was not explained by measurable differences in disease severity or structural factors for non-Hispanic Black men (aPR, 0.81 [CI, 0.64 to 0.97]), other/multiracial men (aPR, 0.58 [CI, 0.20 to 0.97]), Mexican American women (aPR, 0.36 [CI, 0.10 to 0.61]), non-Mexican Hispanic women (aPR, 0.57 [CI, 0.33 to 0.82), non-Hispanic White women (aPR, 0.69 [CI, 0.56 to 0.83]), and non-Hispanic Black women (aPR, 0.75 [CI, 0.57 to 0.92]). LIMITATION: Cross-sectional data; lack of geographic, language, or statin-dose data. CONCLUSION: Statin use disparities for several race-ethnicity-gender groups are not explained by measurable differences in medical appropriateness of therapy, access to health care, and socioeconomic status. These residual disparities may be partially mediated by unobserved processes that contribute to health inequity, including bias, stereotyping, and mistrust. PRIMARY FUNDING SOURCE: National Institutes of Health.

IL-6 enhances CD4 cell motility by sustaining mitochondrial Ca2+ through the noncanonical STAT3 pathway.

Interleukin 6 (IL-6) is known to regulate the CD4 T cell function by inducing gene expression of a number of cytokines through activation of Stat3 transcription factor. Here, we reveal that IL-6 strengthens the mechanics of CD4 T cells. The presence of IL-6 during activation of mouse and human CD4 T cells enhances their motility (random walk and exploratory spread), resulting in an increase in travel distance and higher velocity. This is an intrinsic effect of IL-6 on CD4 T-cell fitness that involves an increase in mitochondrial Ca2+ Although Stat3 transcriptional activity is dispensable for this process, IL-6 uses mitochondrial Stat3 to enhance mitochondrial Ca2+-mediated motility of CD4 T cells. Thus, through a noncanonical pathway, IL-6 can improve competitive fitness of CD4 T cells by facilitating cell motility. These results could lead to alternative therapeutic strategies for inflammatory diseases in which IL-6 plays a pathogenic role.

Come back when you're infected: pharmacy access to sterile syringes in an Arizona Secret Shopper Study, 2023.

BACKGROUND: Pharmacies are critical healthcare partners in community efforts to eliminate bloodborne illnesses. Pharmacy sale of sterile syringes is central to this effort. METHODS: A mixed methods "secret shopper" syringe purchase study was conducted in the fall of 2022 with 38 community pharmacies in Maricopa and Pima Counties, Arizona. Pharmacies were geomapped to within 2 miles of areas identified as having a potentially high volume of illicit drug commerce. Daytime venue sampling was used whereby separate investigators with lived/living drug use experience attempted to purchase syringes without a prescription. Investigator response when prompted for purchase rationale was "to protect myself from HIV and hepatitis C." A 24-item instrument measured sales outcome, pharmacy staff interaction (hostile/neutral/friendly), and the buyer's subjective experience. RESULTS: Only 24.6% (n = 28) of 114 purchase attempts across the 38 pharmacies resulted in syringe sale. Less than one quarter (21.1%) of pharmacies always sold, while 44.7% never sold. Independent and food store pharmacies tended not to sell syringes. There emerged distinct pharmacy staff interactions characterized by body language, customer query, normalization or othering response, response to purchase request and closure. Pharmacy discretion and pharmacy policy not to sell syringes without a prescription limited sterile syringe access. Investigators reported frequent and adverse emotional impact due to pharmacy staff negative and stigmatizing interactions. CONCLUSIONS: Pharmacies miss opportunities to advance efforts to eliminate bloodborne infections by stringent no-sale policy and discretion about syringe sale. State regulatory policy facilitating pharmacy syringe sales, limiting pharmacist discretion for syringe sales, and targeting pharmacy-staff level education may help advance the achievement of public health goals to eliminate bloodborne infections in Arizona.

Strategies used to reduce harms associated with fentanyl exposure among rural people who use drugs: multi-site qualitative findings from the rural opioid initiative.

AIM: Illicitly manufactured fentanyl and its analogs are the primary drivers of opioid overdose deaths in the United States (U.S.). People who use drugs may be exposed to fentanyl or its analogs intentionally or unintentionally. This study sought to identify strategies used by rural people who use drugs to reduce harms associated with unintentional fentanyl exposure. METHODS: This analysis focused on 349 semi-structured qualitative interviews across 10 states and 58 rural counties in the U.S conducted between 2018 and 2020. Interview guides were collaboratively standardized across sites and included questions about drug use history (including drugs currently used, frequency of use, mode of administration) and questions specific to fentanyl. Deductive coding was used to code all data, then inductive coding of overdose and fentanyl codes was conducted by an interdisciplinary writing team. RESULTS: Participants described being concerned that fentanyl had saturated the drug market, in both stimulant and opioid supplies. Participants utilized strategies including: (1) avoiding drugs that were perceived to contain fentanyl, (2) buying drugs from trusted sources, (3) using fentanyl test strips, 4) using small doses and non-injection routes, (5) using with other people, (6) tasting, smelling, and looking at drugs before use, and (7) carrying and using naloxone. Most people who used drugs used a combination of these strategies as there was an overwhelming fear of fatal overdose. CONCLUSION: People who use drugs living in rural areas of the U.S. are aware that fentanyl is in their drug supply and use several strategies to prevent associated harms, including fatal overdose. Increasing access to harm reduction tools (e.g., fentanyl test strips, naloxone) and services (e.g., community drug checking, syringe services programs, overdose prevention centers) should be prioritized to address the polysubstance-involved overdose crisis. These efforts should target persons who use opioids and other drugs that may contain fentanyl.

The antimicrobial drug pyrimethamine inhibits STAT3 transcriptional activity by targeting the enzyme dihydrofolate reductase.

Cancer is often characterized by aberrant gene expression patterns caused by the inappropriate activation of transcription factors. Signal transducer and activator of transcription 3 (STAT3) is a key transcriptional regulator of many protumorigenic processes and is persistently activated in many types of human cancer. However, like many transcription factors, STAT3 has proven difficult to target clinically. To address this unmet clinical need, we previously developed a cell-based assay of STAT3 transcriptional activity and performed an unbiased and high-throughput screen of small molecules known to be biologically active in humans. We identified the antimicrobial drug pyrimethamine as a novel and specific inhibitor of STAT3 transcriptional activity. Here, we show that pyrimethamine does not significantly affect STAT3 phosphorylation, nuclear translocation, or DNA binding at concentrations sufficient to inhibit STAT3 transcriptional activity, suggesting a potentially novel mechanism of inhibition. To identify the direct molecular target of pyrimethamine and further elucidate the mechanism of action, we used a new quantitative proteome profiling approach called proteome integral solubility alteration coupled with a metabolomic analysis. We identified human dihydrofolate reductase as a target of pyrimethamine and demonstrated that the STAT3-inhibitory effects of pyrimethamine are the result of a deficiency in reduced folate downstream of dihydrofolate reductase inhibition, implicating folate metabolism in the regulation of STAT3 transcriptional activity. This study reveals a previously unknown regulatory node of the STAT3 pathway that may be important for the development of novel strategies to treat STAT3-driven cancers.

Prolactin levels and breast cancer risk by tumor expression of prolactin-related markers.

BACKGROUND: Higher circulating prolactin has been associated with increased breast cancer risk. Prolactin binding to the prolactin receptor (PRLR) can activate the transcription factor STAT5, thus, we examined the association between plasma prolactin and breast cancer risk by tumor expression of PRLR, STAT5, and the upstream kinase JAK2. METHODS: Using data from 745 cases and 2454 matched controls in the Nurses' Health Study, we conducted polytomous logistic regression to examine the association between prolactin (> 11 ng/mL vs. ≤ 11 ng/mL) measured within 10 years of diagnosis and breast cancer risk by PRLR (nuclear [N], cytoplasmic [C]), phosphorylated STAT5 (pSTAT5; N, C), and phosphorylated JAK2 (pJAK2; C) tumor expression. Analyses were conducted separately in premenopausal (n = 168 cases, 765 controls) and postmenopausal women (n = 577 cases, 1689 controls). RESULTS: In premenopausal women, prolactin levels > 11 ng/mL were positively associated with risk of tumors positive for pSTAT5-N (OR 2.30, 95% CI 1.02-5.22) and pSTAT5-C (OR 1.64, 95% CI 1.01-2.65), but not tumors that were negative for these markers (OR 0.98, 95% CI 0.65-1.46 and OR 0.73, 95% CI 0.43-1.25; p-heterogeneity = 0.06 and 0.02, respectively). This was stronger when tumors were positive for both pSTAT5-N and pSTAT5-C (OR 2.88, 95% CI 1.14-7.25). No association was observed for PRLR or pJAK2 (positive or negative) and breast cancer risk among premenopausal women. Among postmenopausal women, plasma prolactin levels were positively associated with breast cancer risk irrespective of PRLR, pSTAT5, or pJAK2 expression (all p-heterogeneity ≥ 0.21). CONCLUSION: We did not observe clear differences in the association between plasma prolactin and breast cancer risk by tumor expression of PRLR or pJAK2, although associations for premenopausal women were observed for pSTAT5 positive tumors only. While additional studies are needed, this suggests that prolactin may act on human breast tumor development through alternative pathways.

Quantitative Measures of Right Ventricular Size and Function by Echocardiogram Correlate with Cardiac Catheterization Hemodynamics in Congenital Diaphragmatic Hernia.

OBJECTIVE: To evaluate associations between cardiac catheterization (cath) hemodynamics, quantitative measures of right ventricular (RV) function by echocardiogram, and survival in patients with congenital diaphragmatic hernia (CDH). STUDY DESIGN: This single-center retrospective cohort study enrolled patients with CDH who underwent index cath from 2003 to 2022. Tricuspid annular plane systolic excursion z score, RV fractional area change, RV free wall and global longitudinal strain, left ventricular (LV) eccentricity index, RV/LV ratio, and pulmonary artery acceleration time were measured from preprocedure echocardiograms. Associations between hemodynamic values, echocardiographic measures, and survival were evaluated by Spearman correlation and Wilcoxon rank sum test, respectively. RESULTS: Fifty-three patients (68% left-sided, 74% liver herniation, 57% extracorporeal membrane oxygenation, 93% survival) underwent cath (39 during index hospitalization, 14 later) including device closure of a patent ductus arteriosus in 5. Most patients (n = 31, 58%) were on pulmonary hypertension treatment at cath, most commonly sildenafil (n = 24, 45%) and/or intravenous treprostinil (n = 16, 30%). Overall, hemodynamics were consistent with precapillary pulmonary hypertension. Pulmonary capillary wedge pressure was >15 mm Hg in 2 patients (4%). Lower fractional area change and worse ventricular strain were associated with higher pulmonary artery pressure while higher LV eccentricity index and higher RV/LV ratio were associated with both higher pulmonary artery pressure and higher pulmonary vascular resistance. Hemodynamics did not differ based on survival status. CONCLUSIONS: Worse RV dilation and dysfunction by echocardiogram correlate with higher pulmonary artery pressure and pulmonary vascular resistance on cath in this CDH cohort. These measures may represent novel, noninvasive clinical trial targets in this population.

A JAK/STAT-mediated inflammatory signaling cascade drives oncogenesis in AF10-rearranged AML.

Leukemias bearing fusions of the AF10/MLLT10 gene are associated with poor prognosis, and therapies targeting these fusion proteins (FPs) are lacking. To understand mechanisms underlying AF10 fusion-mediated leukemogenesis, we generated inducible mouse models of acute myeloid leukemia (AML) driven by the most common AF10 FPs, PICALM/CALM-AF10 and KMT2A/MLL-AF10, and performed comprehensive characterization of the disease using transcriptomic, epigenomic, proteomic, and functional genomic approaches. Our studies provide a detailed map of gene networks and protein interactors associated with key AF10 fusions involved in leukemia. Specifically, we report that AF10 fusions activate a cascade of JAK/STAT-mediated inflammatory signaling through direct recruitment of JAK1 kinase. Inhibition of the JAK/STAT signaling by genetic Jak1 deletion or through pharmacological JAK/STAT inhibition elicited potent antioncogenic effects in mouse and human models of AF10 fusion AML. Collectively, our study identifies JAK1 as a tractable therapeutic target in AF10-rearranged leukemias.