Escape from X-inactivation in twins exhibits intra- and inter-individual variability across tissues and is heritable.

X-chromosome inactivation (XCI) silences one X in female cells to balance sex-differences in X-dosage. A subset of X-linked genes escape XCI, but the extent to which this phenomenon occurs and how it varies across tissues and in a population is as yet unclear. To characterize incidence and variability of escape across individuals and tissues, we conducted a transcriptomic study of escape in adipose, skin, lymphoblastoid cell lines and immune cells in 248 healthy individuals exhibiting skewed XCI. We quantify XCI escape from a linear model of genes' allelic fold-change and XIST-based degree of XCI skewing. We identify 62 genes, including 19 lncRNAs, with previously unknown patterns of escape. We find a range of tissue-specificity, with 11% of genes escaping XCI constitutively across tissues and 23% demonstrating tissue-restricted escape, including cell type-specific escape across immune cells of the same individual. We also detect substantial inter-individual variability in escape. Monozygotic twins share more similar escape than dizygotic twins, indicating that genetic factors may underlie inter-individual differences in escape. However, discordant escape also occurs within monozygotic co-twins, suggesting environmental factors also influence escape. Altogether, these data indicate that XCI escape is an under-appreciated source of transcriptional differences, and an intricate phenotype impacting variable trait expressivity in females.

Haematopoietic stem cell-derived immune cells have reduced X chromosome inactivation skewing in systemic lupus erythematosus.

OBJECTIVES: Systemic lupus erythematosus (SLE) shows a marked female bias in prevalence. X chromosome inactivation (XCI) is the mechanism which randomly silences one X chromosome to equalise gene expression between 46, XX females and 46, XY males. Though XCI is expected to result in a random pattern of mosaicism across tissues, some females display a significantly skewed ratio in immune cells, termed XCI-skew. We tested whether XCI was abnormal in females with SLE and hence contributes to sexual dimorphism. METHODS: We assayed XCI in whole blood DNA in 181 female SLE cases, 796 female healthy controls and 10 twin pairs discordant for SLE. Using regression modelling and intra-twin comparisons, we assessed the effect of SLE on XCI and combined clinical, cellular and genetic data via a polygenic score to explore underlying mechanisms. RESULTS: Accommodating the powerful confounder of age, XCI-skew was reduced in females with SLE compared with controls (p=1.3×10-5), with the greatest effect seen in those with more severe disease. Applying an XCI threshold of >80%, we observed XCI-skew in 6.6% of SLE cases compared with 22% of controls. This difference was not explained by differential white cell counts, medication or genetic susceptibility to SLE. Instead, XCI-skew correlated with a biomarker for type I interferon-regulated gene expression. CONCLUSIONS: These results refute current views on XCI-skew in autoimmunity and suggest, in lupus, XCI patterns of immune cells reflect the impact of disease state, specifically interferon signalling, on the haematopoietic stem cells from which they derive.

Genome-wide assessment of genetic risk for systemic lupus erythematosus and disease severity.

Using three European and two Chinese genome-wide association studies (GWAS), we investigated the performance of genetic risk scores (GRSs) for predicting the susceptibility and severity of systemic lupus erythematosus (SLE), using renal disease as a proxy for severity. We used four GWASs to test the performance of GRS both cross validating within the European population and between European and Chinese populations. The performance of GRS in SLE risk prediction was evaluated by receiver operating characteristic (ROC) curves. We then analyzed the polygenic nature of SLE statistically. We also partitioned patients according to their age-of-onset and evaluated the predictability of GRS in disease severity in each age group. We found consistently that the best GRS in the prediction of SLE used SNPs associated at the level of P < 1e-05 in all GWAS data sets and that SNPs with P-values above 0.2 were inflated for SLE true positive signals. The GRS results in an area under the ROC curve ranging between 0.64 and 0.72, within European and between the European and Chinese populations. We further showed a significant positive correlation between a GRS and renal disease in two independent European GWAS (Pcohort1 = 2.44e-08; Pcohort2 = 0.00205) and a significant negative correlation with age of SLE onset (Pcohort1 = 1.76e-12; Pcohort2 = 0.00384). We found that the GRS performed better in the prediction of renal disease in the 'later onset' compared with the 'earlier onset' group. The GRS predicts SLE in both European and Chinese populations and correlates with poorer prognostic factors: young age-of-onset and lupus nephritis.

ACE2 expression in adipose tissue is associated with cardio-metabolic risk factors and cell type composition-implications for COVID-19.

BACKGROUND: COVID-19 severity varies widely. Although some demographic and cardio-metabolic factors, including age and obesity, are associated with increasing risk of severe illness, the underlying mechanism(s) are uncertain. SUBJECTS/METHODS: In a meta-analysis of three independent studies of 1471 participants in total, we investigated phenotypic and genetic factors associated with subcutaneous adipose tissue expression of Angiotensin I Converting Enzyme 2 (ACE2), measured by RNA-Seq, which acts as a receptor for SARS-CoV-2 cellular entry. RESULTS: Lower adipose tissue ACE2 expression was associated with multiple adverse cardio-metabolic health indices, including type 2 diabetes (T2D) (P = 9.14 × 10-6), obesity status (P = 4.81 × 10-5), higher serum fasting insulin (P = 5.32 × 10-4), BMI (P = 3.94 × 10-4), and lower serum HDL levels (P = 1.92 × 10-7). ACE2 expression was also associated with estimated proportions of cell types in adipose tissue: lower expression was associated with a lower proportion of microvascular endothelial cells (P = 4.25 × 10-4) and higher proportion of macrophages (P = 2.74 × 10-5). Despite an estimated heritability of 32%, we did not identify any proximal or distal expression quantitative trait loci (eQTLs) associated with adipose tissue ACE2 expression. CONCLUSIONS: Our results demonstrate that individuals with cardio-metabolic features known to increase risk of severe COVID-19 have lower background ACE2 levels in this highly relevant tissue. Reduced adipose tissue ACE2 expression may contribute to the pathophysiology of cardio-metabolic diseases, as well as the associated increased risk of severe COVID-19.

Probable delirium is a presenting symptom of COVID-19 in frail, older adults: a cohort study of 322 hospitalised and 535 community-based older adults.

BACKGROUND: Frailty, increased vulnerability to physiological stressors, is associated with adverse outcomes. COVID-19 exhibits a more severe disease course in older, comorbid adults. Awareness of atypical presentations is critical to facilitate early identification. OBJECTIVE: To assess how frailty affects presenting COVID-19 symptoms in older adults. DESIGN: Observational cohort study of hospitalised older patients and self-report data for community-based older adults. SETTING: Admissions to St Thomas' Hospital, London with laboratory-confirmed COVID-19. Community-based data for older adults using the COVID Symptom Study mobile application. SUBJECTS: Hospital cohort: patients aged 65 and over (n = 322); unscheduled hospital admission between 1 March 2020 and 5 May 2020; COVID-19 confirmed by RT-PCR of nasopharyngeal swab. Community-based cohort: participants aged 65 and over enrolled in the COVID Symptom Study (n = 535); reported test-positive for COVID-19 from 24 March (application launch) to 8 May 2020. METHODS: Multivariable logistic regression analysis performed on age-matched samples from hospital and community-based cohorts to ascertain association of frailty with symptoms of confirmed COVID-19. RESULTS: Hospital cohort: significantly higher prevalence of probable delirium in the frail sample, with no difference in fever or cough. Community-based cohort: significantly higher prevalence of possible delirium in frailer, older adults and fatigue and shortness of breath. CONCLUSIONS: This is the first study demonstrating higher prevalence of probable delirium as a COVID-19 symptom in older adults with frailty compared to other older adults. This emphasises need for systematic frailty assessment and screening for delirium in acutely ill older patients in hospital and community settings. Clinicians should suspect COVID-19 in frail adults with delirium.

Inter-Individual Variation in Response to Estrogen in Human Breast Explants.

Exposure to estrogen is strongly associated with increased breast cancer risk. While all women are exposed to estrogen, only 12% are expected to develop breast cancer during their lifetime. These women may be more sensitive to estrogen, as rodent models have demonstrated variability in estrogen sensitivity. Our objective was to determine individual variation in expression of estrogen receptor (ER) and estrogen-induced responses in the normal human breast. Human breast tissue from female donors undergoing reduction mammoplasty surgery were collected for microarray analysis of ER expression. To examine estrogen-induced responses, breast tissue from 23 female donors were cultured ex- vivo in basal or 10 nM 17ß-estradiol (E2) media for 4 days. Expression of ER genes (ESR1 and ESR2) increased significantly with age. E2 induced consistent increases in global gene transcription, but expression of target genes AREG, PGR, and TGFß2 increased significantly only in explants from nulliparous women. E2-treatment did not induce consistent changes in proliferation or radiation induced apoptosis. Responses to estrogen are highly variable among women and not associated with levels of ER expression, suggesting differences in intracellular signaling among individuals. The differences in sensitivity to E2-stimulated responses may contribute to variation in risk of breast cancer.

De novo mutations implicate novel genes in systemic lupus erythematosus.

The omnigenic model of complex disease stipulates that the majority of the heritability will be explained by the effects of common variation on genes in the periphery of core disease pathways. Rare variant associations, expected to explain far less of the heritability, may be enriched in core disease genes and thus will be instrumental in the understanding of complex disease pathogenesis and their potential therapeutic targets. Here, using complementary whole-exome sequencing, high-density imputation, and in vitro cellular assays, we identify candidate core genes in the pathogenesis of systemic lupus erythematosus (SLE). Using extreme-phenotype sampling, we sequenced the exomes of 30 SLE parent-affected-offspring trios and identified 14 genes with missense de novo mutations (DNM), none of which are within the >80 SLE susceptibility loci implicated through genome-wide association studies. In a follow-up cohort of 10, 995 individuals of matched European ancestry, we imputed genotype data to the density of the combined UK10K-1000 genomes Phase III reference panel across the 14 candidate genes. Gene-level analyses indicate three functional candidates: DNMT3A, PRKCD, and C1QTNF4. We identify a burden of rare variants across PRKCD associated with SLE risk (P = 0.0028), and across DNMT3A associated with two severe disease prognosis sub-phenotypes (P = 0.0005 and P = 0.0033). We further characterise the TNF-dependent functions of the third candidate gene C1QTNF4 on NF-κB activation and apoptosis, which are inhibited by the p.His198Gln DNM. Our results identify three novel genes in SLE susceptibility and support extreme-phenotype sampling and DNM gene discovery to aid the search for core disease genes implicated through rare variation.

Gene expression signature of atypical breast hyperplasia and regulation by SFRP1.

BACKGROUND: Atypical breast hyperplasias (AH) have a 10-year risk of progression to invasive cancer estimated at 4-7%, with the overall risk of developing breast cancer increased by ~ 4-fold. AH lesions are estrogen receptor alpha positive (ERα+) and represent risk indicators and/or precursor lesions to low grade ERα+ tumors. Therefore, molecular profiles of AH lesions offer insights into the earliest changes in the breast epithelium, rendering it susceptible to oncogenic transformation. METHODS: In this study, women were selected who were diagnosed with ductal or lobular AH, but no breast cancer prior to or within the 2-year follow-up. Paired AH and histologically normal benign (HNB) tissues from patients were microdissected. RNA was isolated, amplified linearly, labeled, and hybridized to whole transcriptome microarrays to determine gene expression profiles. Genes that were differentially expressed between AH and HNB were identified using a paired analysis. Gene expression signatures distinguishing AH and HNB were defined using AGNES and PAM methods. Regulation of gene networks was investigated using breast epithelial cell lines, explant cultures of normal breast tissue and mouse tissues. RESULTS: A 99-gene signature discriminated the histologically normal and AH tissues in 81% of the cases. Network analysis identified coordinated alterations in signaling through ERα, epidermal growth factor receptors, and androgen receptor which were associated with the development of both lobular and ductal AH. Decreased expression of SFRP1 was also consistently lower in AH. Knockdown of SFRP1 in 76N-Tert cells resulted altered expression of 13 genes similarly to that observed in AH. An SFRP1-regulated network was also observed in tissues from mice lacking Sfrp1. Re-expression of SFRP1 in MCF7 cells provided further support for the SFRP1-regulated network. Treatment of breast explant cultures with rSFRP1 dampened estrogen-induced progesterone receptor levels. CONCLUSIONS: The alterations in gene expression were observed in both ductal and lobular AH suggesting shared underlying mechanisms predisposing to AH. Loss of SFRP1 expression is a significant regulator of AH transcriptional profiles driving previously unidentified changes affecting responses to estrogen and possibly other pathways. The gene signature and pathways provide insights into alterations contributing to AH breast lesions.

Mapping eQTLs with RNA-seq reveals novel susceptibility genes, non-coding RNAs and alternative-splicing events in systemic lupus erythematosus.

Studies attempting to functionally interpret complex-disease susceptibility loci by GWAS and eQTL integration have predominantly employed microarrays to quantify gene-expression. RNA-Seq has the potential to discover a more comprehensive set of eQTLs and illuminate the underlying molecular consequence. We examine the functional outcome of 39 variants associated with Systemic Lupus Erythematosus (SLE) through the integration of GWAS and eQTL data from the TwinsUK microarray and RNA-Seq cohort in lymphoblastoid cell lines. We use conditional analysis and a Bayesian colocalisation method to provide evidence of a shared causal-variant, then compare the ability of each quantification type to detect disease relevant eQTLs and eGenes. We discovered the greatest frequency of candidate-causal eQTLs using exon-level RNA-Seq, and identified novel SLE susceptibility genes (e.g. NADSYN1 and TCF7) that were concealed using microarrays, including four non-coding RNAs. Many of these eQTLs were found to influence the expression of several genes, supporting the notion that risk haplotypes may harbour multiple functional effects. Novel SLE associated splicing events were identified in the T-reg restricted transcription factor, IKZF2, and other candidate genes (e.g. WDFY4) through asQTL mapping using the Geuvadis cohort. We have significantly increased our understanding of the genetic control of gene-expression in SLE by maximising the leverage of RNA-Seq and performing integrative GWAS-eQTL analysis against gene, exon, and splice-junction quantifications. We conclude that to better understand the true functional consequence of regulatory variants, quantification by RNA-Seq should be performed at the exon-level as a minimum, and run in parallel with gene and splice-junction level quantification.

Genomic pathology of SLE-associated copy-number variation at the FCGR2C/FCGR3B/FCGR2B locus.

Reduced FCGR3B copy number is associated with increased risk of systemic lupus erythematosus (SLE). The five FCGR2/FCGR3 genes are arranged across two highly paralogous genomic segments on chromosome 1q23. Previous studies have suggested mechanisms for structural rearrangements at the FCGR2/FCGR3 locus and have proposed mechanisms whereby altered FCGR3B copy number predisposes to autoimmunity, but the high degree of sequence similarity between paralogous segments has prevented precise definition of the molecular events and their functional consequences. To pursue the genomic pathology associated with FCGR3B copy-number variation, we integrated sequencing data from fosmid and bacterial artificial chromosome clones and sequence-captured DNA from FCGR3B-deleted genomes to establish a detailed map of allelic and paralogous sequence variation across the FCGR2/FCGR3 locus. This analysis identified two highly paralogous 24.5 kb blocks within the FCGR2C/FCGR3B/FCGR2B locus that are devoid of nonpolymorphic paralogous sequence variations and that define the limits of the genomic regions in which nonallelic homologous recombination leads to FCGR2C/FCGR3B copy-number variation. Further, the data showed evidence of swapping of haplotype blocks between these highly paralogous blocks that most likely arose from sequential ancestral recombination events across the region. Functionally, we found by flow cytometry, immunoblotting and cDNA sequencing that individuals with FCGR3B-deleted alleles show ectopic presence of FcγRIIb on natural killer (NK) cells. We conclude that FCGR3B deletion juxtaposes the 5'-regulatory sequences of FCGR2C with the coding sequence of FCGR2B, creating a chimeric gene that results in an ectopic accumulation of FcγRIIb on NK cells and provides an explanation for SLE risk associated with reduced FCGR3B gene copy number.

Leptin signaling in GABA neurons, but not glutamate neurons, is required for reproductive function.

The adipocyte-derived hormone leptin acts in the brain to modulate the central driver of fertility: the gonadotropin releasing hormone (GnRH) neuronal system. This effect is indirect, as GnRH neurons do not express leptin receptors (LEPRs). Here we test whether GABAergic or glutamatergic neurons provide the intermediate pathway between the site of leptin action and the GnRH neurons. Leptin receptors were deleted from GABA and glutamate neurons using Cre-Lox transgenics, and the downstream effects on puberty onset and reproduction were examined. Both mouse lines displayed the expected increase in body weight and region-specific loss of leptin signaling in the hypothalamus. The GABA neuron-specific LEPR knock-out females and males showed significantly delayed puberty onset. Adult fertility observations revealed that these knock-out animals have decreased fecundity. In contrast, glutamate neuron-specific LEPR knock-out mice displayed normal fertility. Assessment of the estrogenic hypothalamic-pituitary-gonadal axis regulation in females showed that leptin action on GABA neurons is not necessary for estradiol-mediated suppression of tonic luteinizing hormone secretion (an indirect measure of GnRH neuron activity) but is required for regulation of a full preovulatory-like luteinizing hormone surge. In conclusion, leptin signaling in GABAergic (but not glutamatergic neurons) plays a critical role in the timing of puberty onset and is involved in fertility regulation throughout adulthood in both sexes. These results form an important step in explaining the role of central leptin signaling in the reproductive system. Limiting the leptin-to-GnRH mediators to GABAergic cells will enable future research to focus on a few specific types of neurons.

Multiplexed imaging of nanoparticles in tissues using laser desorption/ionization mass spectrometry.

Imaging of nanomaterials in biological tissues provides vital information for the development of nanotherapeutics and diagnostics. Multiplexed imaging of different nanoparticles (NPs) greatly reduces costs, the need to use multiple animals, and increases the biodistribution information that can enhance diagnostic applications and accelerate the screening of potential therapeutics. Various approaches have been developed for imaging NPs; however, the readout of existing imaging techniques relies on specific properties of the core material or surface ligands, and these techniques are limited because of the relatively small number of NPs that can be simultaneously measured in a single experiment. Here, we demonstrate the use of laser desorption/ionization mass spectrometry (LDI-MS) in an imaging format to investigate surface chemistry dictated intraorgan distribution of NPs. This new LDI-MS imaging method enables multiplexed imaging of NPs with potentially unlimited readouts and without additional labeling of the NPs. It provides the capability to detect and image attomole levels of NPs with almost no interferences from biomolecules. Using this new imaging approach, we find that the intraorgan distributions of same-sized NPs are directly linked to their surface chemistry.

Oncogenic transformation of mammary epithelial cells by transforming growth factor beta independent of mammary stem cell regulation.

BACKGROUND: Transforming growth factor beta (TGFß) is transiently increased in the mammary gland during involution and by radiation. While TGFß normally has a tumour suppressor role, prolonged exposure to TGFß can induce an oncogenic epithelial to mesenchymal transition (EMT) program in permissive cells and initiate the generation of cancer stem cells. Our objective is to mimic the transient exposure to TGFß during involution to determine the persistent effects on premalignant mammary epithelium. METHOD: CDßGeo cells, a transplantable mouse mammary epithelial cell line, were treated in vitro for 14 days with TGFß (5 ng/ml). The cells were passaged for an additional 14 days in media without TGFß and then assessed for markers of EMT and transformation. RESULTS: The 14-day exposure to TGFß induced EMT and transdifferentiation in vitro that persists after withdrawal of TGFß. TGFß-treated cells are highly tumorigenic in vivo, producing invasive solid de-differentiated tumours (100%; latency 6.7 weeks) compared to control (43%; latency 32.7 weeks). Although the TGFß-treated cells have initiated a persistent EMT program, the stem cell population was unchanged relative to the controls. The gene expression profiles of TGFß-treated cells demonstrate de-differentiation with decreases in the expression of genes that define luminal, basal and stem cells. Additionally, the gene expression profiles demonstrate increases in markers of EMT, growth factor signalling, TGFß2 and changes in extra cellular matrix. CONCLUSION: This model demonstrates full oncogenic EMT without an increase in stem cells, serving to separate EMT markers from stem cell markers.

No effects of short-term sleep restriction, in a controlled feeding setting, on lipid profiles in normal-weight adults.

Short sleep has been associated with cardiovascular risk. The aim of this study was to determine the impact of short-term sleep restriction on lipid profiles and resting blood pressure factors in young, normal-weight individuals (14 men, 13 women). Participants were randomized to five nights of either habitual (9 h) or short (4 h) sleep in a cross-over design separated by a 3-week washout period. There was no sleep × day interaction on lipid profile and blood pressure. Short-term sleep restriction does not alter lipid profiles and resting blood pressure in healthy, normal-weight individuals. The association between short sleep and increased cardiovascular risk reported in the epidemiological literature may be the result of long-term sleep restriction and poor lifestyle choices.

COVID-19 vaccine safety inquiries to the centers for disease control and prevention immunization safety office.

BACKGROUND: Following the authorization and recommendations for use of the U.S. COVID-19 vaccines, the Centers for Disease Control and Prevention (CDC)'s Immunization Safety Office (ISO) responded to inquiries and questions from public health officials, healthcare providers, and the general public on COVID-19 vaccine safety. METHODS: We describe COVID-19 vaccine safety inquiries, by topic, received and addressed by ISO from December 1, 2020-August 31, 2022. RESULTS: Of the 1978 COVID-19 vaccine-related inquiries received, 1655 specifically involved vaccine safety topics. The most frequently asked-about topics included deaths following vaccination, myocarditis, pregnancy, and reproductive health outcomes, understanding or interpreting data from the Vaccine Adverse Event Reporting System (VAERS), and thrombosis with thrombocytopenia syndrome. CONCLUSIONS: Inquiries about vaccine safety generally reflect issues that receive media attention. ISO will continue to monitor vaccine safety inquiries and provide accurate and timely information to healthcare providers, public health officials, and the general public.

Trends in Ductus Arteriosus Stent Versus Blalock-Taussig-Thomas Shunt Use and Comparison of Cost, Length of Stay, and Short-Term Outcomes in Neonates With Ductal-Dependent Pulmonary Blood Flow: An Observational Study Using the Pediatric Health Information Systems Database.

BACKGROUND: The modified Blalock-Taussig-Thomas shunt is the gold standard palliation for securing pulmonary blood flow in infants with ductal-dependent pulmonary blood flow. Recently, the ductus arteriosus stent (DAS) has become a viable alternative. METHODS AND RESULTS: This was a retrospective multicenter study of neonates ≤30 days undergoing DAS or Blalock-Taussig-Thomas shunt placement between January 1, 2017 and December 31, 2020 at hospitals reporting to the Pediatric Health Information Systems database. We performed generalized linear mixed-effects modeling to evaluate trends in intervention and intercenter variation, propensity score adjustment and inverse probability weighting with linear mixed-effects modeling to analyze length of stay and cost of hospitalization, and generalized linear mixed modeling to analyze differences in 30-day outcomes. There were 1874 subjects (58% male, 61% White) from 45 centers (29% DAS). Odds of DAS increased with time (odds ratio [OR] 1.23, annually, P<0.01 [95% CI, 1.10-1.38]) with significant intercenter variation (median OR, 3.81 [95% CI, 2.74-5.91]). DAS was associated with shorter hospital length of stay (ratio of geometric means, 0.76 [95% CI, 0.63-0.91]), shorter intensive care unit length of stay (ratio of geometric means, 0.77 [95% CI, 0.61-0.97]), and less expensive hospitalization (ratio of geometric means, 0.70 [95% CI, 0.56-0.87]). Intervention was not significantly associated with odds of 30-day transplant-free survival (OR,1.18 [95% CI, 0.70-1.99]) or freedom from catheter reintervention (OR, 1.02 [95% CI, 0.65-1.58]), but DAS was associated with 30-day freedom from composite adverse outcome (OR, 1.51 [95% CI, 1.11-2.05]). CONCLUSIONS: Use of DAS is increasing, but there is variability across centers. Though odds of transplant-free survival and reintervention were not significantly different after DAS, and DAS was associated with shorter length of stay and lower in-hospital costs.

Impact of Ventricular Dysfunction and Atrioventricular Valve Regurgitation on Pre-Fontan Attrition.

BACKGROUND: There is a significant incidence of pre-Fontan attrition-defined as failure to undergo Fontan completion-after superior cavopulmonary connection. This study investigated the impact of at least moderate ventricular dysfunction (VD) and atrioventricular valve regurgitation (AVVR) on pre-Fontan attrition. METHODS: This single-center retrospective cohort study included all infants who underwent Norwood palliation from 2008 to 2020 and subsequently underwent superior cavopulmonary connection. Pre-Fontan attrition was defined as death, listing for heart transplantation before Fontan completion, or unsuitability for Fontan completion. The study's secondary outcome was transplant-free survival. RESULTS: Pre-Fontan attrition occurred in 34 of 267 patients (12.7%). Isolated VD was not associated with attrition. However, patients with isolated AVVR had 5 times the odds of attrition (odds ratio, 5.4; 95% CI 1.8-16.2), and patients with both VD and AVVR had 20 times the odds of attrition (odds ratio, 20.1; 95% CI 7.7-52.8) compared with patients without VD or AVVR. Only patients with both VD and AVVR had significantly worse transplant-free survival compared with patients without VD or AVVR (hazard ratio, 7.7; 95% CI 2.8-21.6). CONCLUSIONS: The additive effect of VD and AVVR is a powerful contributor to pre-Fontan attrition. Future research investigating therapies that can mitigate the degree of AVVR may help improve Fontan completion rates and long-term outcomes.

Adipose tissue eQTL meta-analysis reveals the contribution of allelic heterogeneity to gene expression regulation and cardiometabolic traits.

Complete characterization of the genetic effects on gene expression is needed to elucidate tissue biology and the etiology of complex traits. Here, we analyzed 2,344 subcutaneous adipose tissue samples and identified 34K conditionally distinct expression quantitative trait locus (eQTL) signals in 18K genes. Over half of eQTL genes exhibited at least two eQTL signals. Compared to primary signals, non-primary signals had lower effect sizes, lower minor allele frequencies, and less promoter enrichment; they corresponded to genes with higher heritability and higher tolerance for loss of function. Colocalization of eQTL with conditionally distinct genome-wide association study signals for 28 cardiometabolic traits identified 3,605 eQTL signals for 1,861 genes. Inclusion of non-primary eQTL signals increased colocalized signals by 46%. Among 30 genes with ≥2 pairs of colocalized signals, 21 showed a mediating gene dosage effect on the trait. Thus, expanded eQTL identification reveals more mechanisms underlying complex traits and improves understanding of the complexity of gene expression regulation.

The rs1143679 (R77H) lupus associated variant of ITGAM (CD11b) impairs complement receptor 3 mediated functions in human monocytes.

OBJECTIVES: The rs1143679 variant of ITGAM, encoding the R77H variant of CD11b (part of complement receptor 3; CR3), is among the strongest genetic susceptibility effects in human systemic lupus erythematosus (SLE). The authors aimed to demonstrate R77H function in ex-vivo human cells. METHODS: Monocytes/monocyte-derived macrophages from healthy volunteers homozygous for either wild type (WT) or 77H CD11b were studied. The genotype-specific expression of CD11b, and CD11b activation using conformation-specific antibodies were measured. Genotype-specific differences in iC3b-mediated phagocytosis, adhesion to a range of ligands and the secretion of cytokines following CR3 ligation were studied. The functionality of R77H was confirmed by replicating findings in COS7 cells expressing variant-specific CD11b. RESULTS: No genotype-specific difference in CD11b expression or in the expression of CD11b activation epitopes was observed. A 31% reduction was observed in the phagocytosis of iC3b opsonised sheep erythrocytes (sRBC(iC3b)) by 77H cells (p=0.003) and reduced adhesion to a range of ligands: notably a 24% reduction in adhesion to iC3b (p=0.014). In transfected COS7 cells, a 42% reduction was observed in phagocytosis by CD11b (77H)-expressing cells (p=0.004). A significant inhibition was seen in the release of Toll-like receptor 7/8-induced pro-inflammatory cytokines from WT monocytes when CR3 was pre-engaged using sRBC(iC3b), but no inhibition in 77H monocytes resulting in a significant difference between genotypes (interleukin (IL)-1ß p=0.030; IL-6 p=0.029; tumour necrosis factor alpha p=0.027). CONCLUSIONS: The R77H variant impairs a broad range of CR3 effector functions in human monocytes. This study discusses how perturbation of this pathway may predispose to SLE.

Alterations in sleep architecture in response to experimental sleep curtailment are associated with signs of positive energy balance.

Sleep reduction is associated with increased energy intake and weight gain, though few studies have explored the relationship between sleep architecture and energy balance measures in the context of experimental sleep restriction. Fourteen males and 13 females (body mass index: 22-26 kg/m(2)) participated in a crossover sleep curtailment study. Participants were studied under two sleep conditions: short (4 h/night; 0100-0500 h) and habitual (9 h/night; 2200-0700 h), for 5 nights each. Sleep was polysomnographically recorded nightly. Outcome measures included resting metabolic rate (RMR), feelings of appetite-satiety, and ad libitum food intake. Short sleep resulted in reductions in stage 2 sleep and rapid eye movement (REM) sleep duration (P < 0.001), as well as decreased percentage of stage 2 sleep and REM sleep and increased slow wave sleep (SWS) percentage (P < 0.05). Linear mixed model analysis demonstrated a positive association between stage 2 sleep duration and RMR (P = 0.051). Inverse associations were observed between REM sleep duration and hunger (P = 0.031) and between stage 2 sleep duration and appetite for sweet (P = 0.015) and salty (P = 0.046) foods. Stage 2 sleep percentage was inversely related to energy consumed (P = 0.024). Stage 2 sleep (P = 0.005), SWS (P = 0.008), and REM sleep (P = 0.048) percentages were inversely related to fat intake, and SWS (P = 0.040) and REM sleep (P = 0.050) were inversely related to carbohydrate intake. This study demonstrates that changes in sleep architecture are associated with markers of positive energy balance and indicate a means by which exposure to short sleep duration and/or an altered sleep architecture profile may lead to excess weight gain over time.