Mast cell activation disrupts interactions between endothelial cells and pericytes during early life allergic asthma.

Allergic asthma generally starts during early life and is linked to substantial tissue remodeling and lung dysfunction. Although angiogenesis is a feature of the disrupted airway, the impact of allergic asthma on the pulmonary microcirculation during early life is unknown. Here, using quantitative imaging in precision-cut lung slices (PCLSs), we report that exposure of neonatal mice to house dust mite (HDM) extract disrupts endothelial cell/pericyte interactions in adventitial areas. Central to the blood vessel structure, the loss of pericyte coverage was driven by mast cell (MC) proteases, such as tryptase, that can induce pericyte retraction and loss of the critical adhesion molecule N-cadherin. Furthermore, spatial transcriptomics of pediatric asthmatic endobronchial biopsies suggests intense vascular stress and remodeling linked with increased expression of MC activation pathways in regions enriched in blood vessels. These data provide previously unappreciated insights into the pathophysiology of allergic asthma with potential long-term vascular defects.

Validation of a Novel Method to Assess the Clinical Quality of Information in Pregnancy-Related Pharmacovigilance Case Reports: A ConcePTION Project.

BACKGROUND: To assess the causal relationship between a medicinal product and a reported event, relevant information needs to be present. Information elements for assessing cases of exposure to medicinal products during pregnancy were predefined and used in a new tool to assess the quality of information. However, the extent in which the presence or absence of these predefined information elements is associated with the overall clinical quality of these cases, as evaluated by pharmacovigilance experts, remains uncertain. OBJECTIVE: We aimed to validate a novel method to assess the clinical quality of information in real-world pregnancy pharmacovigilance case reports. METHODS: The clinical quality of case reports regarding medicinal product exposure and pregnancy-related outcomes was appraised from spontaneous reports, literature, Teratology Information Services (UK and Switzerland), The Dutch Pregnancy Drug Register, the Gilenya pregnancy registry and the Enhanced PV programme of Novartis. Assessment was done by means of the novel standardised tool based on the presence and relevance of information, and by expert judgement. The novel tool was validated compared to the expert assessment as the gold standard expressed as the area under the receiver operating characteristic curves, after which the sensitivity and specificity were calculated using cross-tabulations. Inter-rater variability was determined by means of weighted Cohen's kappa. RESULTS: One hundred and eighty-six case reports were included. The clinical quality score as assessed by the novel method was divided into three categories with cut-off values of 45% (poor to intermediate) and 65% (intermediate to excellent). Sensitivity was 0.93 and 0.96 for poor to intermediate and intermediate to excellent, respectively. Specificity was respectively 0.52 and 0.73. Inter-rater variability was 0.65 (95% confidence interval 0.53-0.78) for the newly developed approach, and 0.40 (95% confidence interval 0.28-0.52) for the gold standard assessment. CONCLUSIONS: The tool described in this study using the presence and relevance of elements of information is the first designed, validated and standardised method for the assessment of the quality of information of case reports in pregnancy pharmacovigilance data. This method confers less inter-rater variability compared with a quality assessment by experts of pregnancy-related pharmacovigilance data.

Improving Data Collection in Pregnancy Safety Studies: Towards Standardisation of Data Elements in Pregnancy Reports from Public and Private Partners, A Contribution from the ConcePTION Project.

INTRODUCTION AND OBJECTIVE: The ConcePTION project aims to improve the way medication use during pregnancy is studied. This includes exploring the possibility of developing a distributed data processing and analysis infrastructure using a common data model that could form a foundational platform for future surveillance and research. A prerequisite would be that data from various data access providers (DAPs) can be harmonised according to an agreed set of standard rules concerning the structure and content of the data. To do so, a reference framework of core data elements (CDEs) recommended for primary data studies on drug safety during pregnancy was previously developed. The aim of this study was to assess the ability of several public and private DAPs using different primary data sources focusing on multiple sclerosis, as a pilot, to map their respective data variables and definitions with the CDE recommendations framework. METHODS: Four pregnancy registries (Gilenya, Novartis; Aubagio, Sanofi; the Organization of Teratology Information Specialists [OTIS]; Aubagio, Sanofi; the Dutch Pregnancy Drug Register, Lareb), two enhanced pharmacovigilance programmes (Gilenya PRIM, Novartis; MAPLE-MS, Merck Healthcare KGaA) and four Teratology Information Services (UK TIS, Jerusalem TIS, Zerifin TIS, Swiss TIS) participated in the study. The ConcePTION primary data source CDE includes 51 items covering administrative functions, the description of pregnancy, maternal medical history, maternal illnesses arising in pregnancy, delivery details, and pregnancy and infant outcomes. For each variable in the CDE, the DAPs identified whether their variables were: identical to the one mentioned in the CDE; derived; similar but with a divergent definition; or not available. RESULTS: The majority of the DAP data variables were either directly taken (85%, n = 305/357, range 73-94% between DAPs) or derived by combining different variables (12%, n = 42/357, range 0-24% between DAPs) to conform to the CDE variables and definitions. For very few of the DAP variables, alignment with the CDE items was not possible, either because of divergent definitions (1%, n = 3/357, range 0-2% between DAPs) or because the variables were not available (2%, n = 7/357, range 0-4% between DAPs). CONCLUSIONS: Data access providers participating in this study presented a very high proportion of variables matching the CDE items, indicating that alignment of definitions and harmonisation of data analysis by different stakeholders to accelerate and strengthen pregnancy pharmacovigilance safety data analyses could be feasible.

Lung extracellular matrix modulates KRT5+ basal cell activity in pulmonary fibrosis.

Aberrant expansion of KRT5+ basal cells in the distal lung accompanies progressive alveolar epithelial cell loss and tissue remodelling during fibrogenesis in idiopathic pulmonary fibrosis (IPF). The mechanisms determining activity of KRT5+ cells in IPF have not been delineated. Here, we reveal a potential mechanism by which KRT5+ cells migrate within the fibrotic lung, navigating regional differences in collagen topography. In vitro, KRT5+ cell migratory characteristics and expression of remodelling genes are modulated by extracellular matrix (ECM) composition and organisation. Mass spectrometry- based proteomics revealed compositional differences in ECM components secreted by primary human lung fibroblasts (HLF) from IPF patients compared to controls. Over-expression of ECM glycoprotein, Secreted Protein Acidic and Cysteine Rich (SPARC) in the IPF HLF matrix restricts KRT5+ cell migration in vitro. Together, our findings demonstrate how changes to the ECM in IPF directly influence KRT5+ cell behaviour and function contributing to remodelling events in the fibrotic niche.

Neurodevelopment of babies born to mothers with epilepsy: A prospective observational cohort study.

OBJECTIVE: Despite widespread monotherapy use of lamotrigine or levetiracetam during pregnancy, prospectively collected, blinded child development data are still limited. The NaME (Neurodevelopment of Babies Born to Mothers With Epilepsy) Study prospectively recruited a new cohort of women with epilepsy and their offspring for longitudinal follow-up. METHODS: Pregnant women of <21 weeks gestation (n = 401) were recruited from 21 hospitals in the UK. Data collection occurred during pregnancy (recruitment, trimester 3) and at 12 and 24 months of age. The primary outcome was blinded assessment of infant cognitive, language, and motor development on the Bayley Scales of Infant and Toddler Development (3rd edition) at 24 months of age with supplementary parent reporting on the Vinelands Adaptive Behavior Scales (2nd edition). RESULTS: There were 394 live births, with 277 children (70%) completing the Bayley assessment at 24 months. There was no evidence of an association of prenatal exposure to monotherapy lamotrigine (-.74, SE = 2.9, 95% confidence interval [CI] = -6.5 to 5.0, p = .80) or levetiracetam (-1.57, SE = 3.1, 95% CI = -4.6 to 7.7, p = .62) with poorer infant cognition, following adjustment for other maternal and child factors in comparison to nonexposed children. Similar results were observed for language and motor scores. There was no evidence of an association between increasing doses of either lamotrigine or levetiracetam. Nor was there evidence that higher dose folic acid supplementation (≥5 mg/day) or convulsive seizure exposure was associated with child development scores. Continued infant exposure to antiseizure medications through breast milk was not associated with poorer outcomes, but the number of women breastfeeding beyond 3 months was low. SIGNIFICANCE: These data are reassuring for infant development following in utero exposure to monotherapy lamotrigine or levetiracetam, but child development is dynamic, and future follow-up is required to rule out later emerging effects.

A meta-analysis of genome-wide association studies of childhood wheezing phenotypes identifies ANXA1 as a susceptibility locus for persistent wheezing.

Background: Many genes associated with asthma explain only a fraction of its heritability. Most genome-wide association studies (GWASs) used a broad definition of 'doctor-diagnosed asthma', thereby diluting genetic signals by not considering asthma heterogeneity. The objective of our study was to identify genetic associates of childhood wheezing phenotypes. Methods: We conducted a novel multivariate GWAS meta-analysis of wheezing phenotypes jointly derived using unbiased analysis of data collected from birth to 18 years in 9568 individuals from five UK birth cohorts. Results: Forty-four independent SNPs were associated with early-onset persistent, 25 with pre-school remitting, 33 with mid-childhood remitting, and 32 with late-onset wheeze. We identified a novel locus on chr9q21.13 (close to annexin 1 [ANXA1], p<6.7 × 10-9), associated exclusively with early-onset persistent wheeze. We identified rs75260654 as the most likely causative single nucleotide polymorphism (SNP) using Promoter Capture Hi-C loops, and then showed that the risk allele (T) confers a reduction in ANXA1 expression. Finally, in a murine model of house dust mite (HDM)-induced allergic airway disease, we demonstrated that anxa1 protein expression increased and anxa1 mRNA was significantly induced in lung tissue following HDM exposure. Using anxa1-/- deficient mice, we showed that loss of anxa1 results in heightened airway hyperreactivity and Th2 inflammation upon allergen challenge. Conclusions: Targeting this pathway in persistent disease may represent an exciting therapeutic prospect. Funding: UK Medical Research Council Programme Grant MR/S025340/1 and the Wellcome Trust Strategic Award (108818/15/Z) provided most of the funding for this study.

Three-quarters of children hospitalized for wheezing or asthma symptoms are preschool-aged. Some will continue to experience breathing difficulties through childhood and adulthood. Others will undergo a complete resolution of their symptoms by the time they reach elementary school. The varied trajectories of young children with wheezing suggest that it is not a single disease. There are likely different genetic or environmental causes. Despite these differences, wheezing treatments for young children are 'one size fits all.' Studying the genetic underpinnings of wheezing may lead to more customized treatment options. Granell et al. studied the genetic architecture of different patterns of wheezing from infancy to adolescence. To do so, they used machine learning technology to analyze the genomes of 9,568 individuals, who participated in five studies in the United Kingdom from birth to age 18. The experiments found a new genetic variation in the ANXA1 gene linked with persistent wheezing starting in early childhood. By comparing mice with and without this gene, Granell et al. showed that the protein encoded by ANXA1 controls inflammation in the lungs in response to allergens. Animals lacking the protein develop worse lung inflammation after exposure to dust mite allergens. Identifying a new gene linked to a specific subtype of wheezing might help scientists develop better strategies to diagnose, treat, and prevent asthma. More studies are needed on the role of the protein encoded by ANXA1 in reducing allergen-triggered lung inflammation to determine if this protein or therapies that boost its production may offer relief for chronic lung inflammation.

Core Data Elements for Pregnancy Pharmacovigilance Studies Using Primary Source Data Collection Methods: Recommendations from the IMI ConcePTION Project.

INTRODUCTION AND OBJECTIVE: The risks and benefits of medication use in pregnancy are typically established through post-marketing observational studies. As there is currently no standardised or systematic approach to the post-marketing assessment of medication safety in pregnancy, data generated through pregnancy pharmacovigilance (PregPV) research can be heterogenous and difficult to interpret. The aim of this article is to describe the development of a reference framework of core data elements (CDEs) for collection in primary source PregPV studies that can be used to standardise data collection procedures and, thereby, improve data harmonisation and evidence synthesis capabilities. METHODS: This CDE reference framework was developed within the Innovative Medicines Initiative (IMI) ConcePTION project by experts in pharmacovigilance, pharmacoepidemiology, medical statistics, risk-benefit communication, clinical teratology, reproductive toxicology, genetics, obstetrics, paediatrics, and child psychology. The framework was produced through a scoping review of data collection systems used by established PregPV datasets, followed by extensive discussion and debate around the value, definition, and derivation of each data item identified from these systems. RESULTS: The finalised listing of CDEs comprises 98 individual data elements, arranged into 14 tables of related fields. These data elements are openly available on the European Network of Teratology Information Services (ENTIS) website ( http://www.entis-org.eu/cde ). DISCUSSION: With this set of recommendations, we aim to standardise PregPV primary source data collection processes to improve the speed at which high-quality evidence-based statements can be provided about the safety of medication use in pregnancy.

Immunoregulation of asthma by type 2 cytokine therapies: Treatments for all ages?

Asthma is classically considered to be a disease of type 2 immune dysfunction, since many patients exhibit the consequences of excess secretion of cytokines such as IL-4, IL-5, and IL-13 concomitant with inflammation typified by eosinophils. Mouse and human disease models have determined that many of the canonical pathophysiologic features of asthma may be caused by these disordered type 2 immune pathways. As such considerable efforts have been made to develop specific drugs targeting key cytokines. There are currently available multiple biologic agents that successfully reduce the functions of IL-4, IL-5, and IL-13 in patients, and many improve the course of severe asthma. However, none are curative and do not always minimize the key features of disease, such as airway hyperresponsiveness. Here, we review the current therapeutic landscape targeting type 2 immune cytokines and discuss evidence of efficacy and limitations of their use in adults and children with asthma.

Bacterial Glycoengineering as a Biosynthetic Route to Customized Glycomolecules.

Bacteria have garnered increased interest in recent years as a platform for the biosynthesis of a variety of glycomolecules such as soluble oligosaccharides, surface-exposed carbohydrates, and glycoproteins. The ability to engineer commonly used laboratory species such as Escherichia coli to efficiently synthesize non-native sugar structures by recombinant expression of enzymes from various carbohydrate biosynthesis pathways has allowed for the facile generation of important products such as conjugate vaccines, glycosylated outer membrane vesicles, and a variety of other research reagents for studying and understanding the role of glycans in living systems. This chapter highlights some of the key discoveries and technologies for equipping bacteria with the requisite biosynthetic machinery to generate such products. As the bacterial glyco-toolbox continues to grow, these technologies are expected to expand the range of glycomolecules produced recombinantly in bacterial systems, thereby opening up this platform to an even larger number of applications.

Nine newly identified individuals refine the phenotype associated with MYT1L mutations.

Both point mutations and deletions of the MYT1L gene as well as microdeletions of chromosome band 2p25.3 including MYT1L are associated with intellectual disability, obesity, and behavioral problems. Thus, MYT1L is assumed to be the-at least mainly-causative gene in the 2p25.3 deletion syndrome. Here, we present comprehensive descriptions of nine novel individuals bearing MYT1L mutations; most of them single nucleotide variants (SNVs). This increases the number of known individuals with causative deletions or SNVs of MYT1L to 51. Since eight of the nine novel patients bear mutations affecting MYT1L only, the total number of such individuals now nearly equals the number of individuals with larger microdeletions affecting additional genes, allowing for a comprehensive phenotypic comparison of these two patient groups. For example, 55% of the individuals with mutations affecting MYT1L only were overweight or obese as compared to 86% of the individuals with larger microdeletions. A similar trend was observed regarding short stature with 5 versus 35%, respectively. However, these differences were nominally significant only after correction for multiple testing, further supporting the hypothesis that MYT1L haploinsufficiency is central to the 2p25.3 deletion phenotype. Most importantly, the large number of individuals with MYT1L mutations presented and reviewed here allowed for the delineation of a more comprehensive clinical picture. Seizures, postnatal short stature, macrocephaly, and microcephaly could be shown to be over-represented among individuals with MYT1L mutations.

The clinical presentation caused by truncating CHD8 variants.

Variants in the chromodomain helicase DNA-binding protein 8 (CHD8) have been associated with intellectual disability (ID), autism spectrum disorders (ASDs) and overgrowth and CHD8 is one of the causative genes for OGID (overgrowth and ID). We investigated 25 individuals with CHD8 protein truncating variants (PTVs), including 10 previously unreported patients and found a male to female ratio of 2.7:1 (19:7) and a pattern of common features: macrocephaly (62.5%), tall stature (47%), developmental delay and/or intellectual disability (81%), ASDs (84%), sleep difficulties (50%), gastrointestinal problems (40%), and distinct facial features. Most of the individuals in this cohort had moderate-to-severe ID, some had regression of speech (37%), seizures (27%) and hypotonia (27%) and two individuals were non-ambulant. Our study shows that haploinsufficiency of CHD8 is associated with a distinctive OGID syndrome with pronounced autistic traits and supports a sex-dependent penetrance of CHD8 PTVs in humans.

Live imaging of alveologenesis in precision-cut lung slices reveals dynamic epithelial cell behaviour.

Damage to alveoli, the gas-exchanging region of the lungs, is a component of many chronic and acute lung diseases. In addition, insufficient generation of alveoli results in bronchopulmonary dysplasia, a disease of prematurity. Therefore visualising the process of alveolar development (alveologenesis) is critical for our understanding of lung homeostasis and for the development of treatments to repair and regenerate lung tissue. Here we show live alveologenesis, using long-term, time-lapse imaging of precision-cut lung slices. We reveal that during this process, epithelial cells are highly mobile and we identify specific cell behaviours that contribute to alveologenesis: cell clustering, hollowing and cell extension. Using the cytoskeleton inhibitors blebbistatin and cytochalasin D, we show that cell migration is a key driver of alveologenesis. This study reveals important novel information about lung biology and provides a new system in which to manipulate alveologenesis genetically and pharmacologically.

Glyco-recoded Escherichia coli: Recombineering-based genome editing of native polysaccharide biosynthesis gene clusters.

Recombineering-based redesign of bacterial genomes by adding, removing or editing large segments of genomic DNA is emerging as a powerful technique for expanding the range of functions that an organism can perform. Here, we describe a glyco-recoding strategy whereby major non-essential polysaccharide gene clusters in K-12 Escherichia coli are replaced with orthogonal glycosylation components for both biosynthesis of heterologous glycan structures and site-specific glycan conjugation to target proteins. Specifically, the native enterobacterial common antigen (ECA) and O-polysaccharide (O-PS) antigen loci were systematically replaced with ∼9-10 kbp of synthetic DNA encoding Campylobacter jejuni enzymes required for asparagine-linked (N-linked) protein glycosylation. Compared to E. coli cells carrying the same glycosylation machinery on extrachromosomal plasmids, glyco-recoded strains attached glycans to acceptor protein targets with equal or greater efficiency while exhibiting markedly better growth phenotypes and higher glycoprotein titers. Overall, our results define a convenient and reliable framework for bacterial glycome editing that provides a more stable route for chemical diversification of proteins in vivo and effectively expands the bacterial glycoengineering toolkit.

Time-lapse Imaging of Alveologenesis in Mouse Precision-cut Lung Slices.

Alveoli are the gas-exchange units of lung. The process of alveolar development, alveologenesis, is regulated by a complex network of signaling pathways that act on various cell types including alveolar type I and II epithelial cells, fibroblasts and the vascular endothelium. Dysregulated alveologenesis results in bronchopulmonary dysplasia in neonates and in adults, disrupted alveolar regeneration is associated with chronic lung diseases including COPD and pulmonary fibrosis. Therefore, visualizing alveologenesis is critical to understand lung homeostasis and for the development of effective therapies for incurable lung diseases. We have developed a technique to visualize alveologenesis in real-time using a combination of widefield microscopy and image deconvolution of precision-cut lung slices. Here, we describe this live imaging technique in step-by-step detail. This time-lapse imaging technique can be used to capture the dynamics of individual cells within tissue slices over a long time period (up to 16 h), with minimal loss of fluorescence or cell toxicity.

Author Correction: Single-pot glycoprotein biosynthesis using a cell-free transcription-translation system enriched with glycosylation machinery.

The original version of this Article contained an error in Figure 2, wherein the bottom right western blot panel in Figure 2a was blank. This has now been corrected in both the PDF and HTML versions of the Article.

Single-pot glycoprotein biosynthesis using a cell-free transcription-translation system enriched with glycosylation machinery.

The emerging discipline of bacterial glycoengineering has made it possible to produce designer glycans and glycoconjugates for use as vaccines and therapeutics. Unfortunately, cell-based production of homogeneous glycoproteins remains a significant challenge due to cell viability constraints and the inability to control glycosylation components at precise ratios in vivo. To address these challenges, we describe a novel cell-free glycoprotein synthesis (CFGpS) technology that seamlessly integrates protein biosynthesis with asparagine-linked protein glycosylation. This technology leverages a glyco-optimized Escherichia coli strain to source cell extracts that are selectively enriched with glycosylation components, including oligosaccharyltransferases (OSTs) and lipid-linked oligosaccharides (LLOs). The resulting extracts enable a one-pot reaction scheme for efficient and site-specific glycosylation of target proteins. The CFGpS platform is highly modular, allowing the use of multiple distinct OSTs and structurally diverse LLOs. As such, we anticipate CFGpS will facilitate fundamental understanding in glycoscience and make possible applications in on demand biomanufacturing of glycoproteins.

The Tatton-Brown-Rahman Syndrome: A clinical study of 55 individuals with de novo constitutive DNMT3A variants.

Tatton-Brown-Rahman syndrome (TBRS; OMIM 615879), also known as the DNMT3A-overgrowth syndrome, is an overgrowth intellectual disability syndrome first described in 2014 with a report of 13 individuals with constitutive heterozygous DNMT3A variants. Here we have undertaken a detailed clinical study of 55 individuals with de novoDNMT3A variants, including the 13 previously reported individuals. An intellectual disability and overgrowth were reported in >80% of individuals with TBRS and were designated major clinical associations. Additional frequent clinical associations (reported in 20-80% individuals) included an evolving facial appearance with low-set, heavy, horizontal eyebrows and prominent upper central incisors; joint hypermobility (74%); obesity (weight ³2SD, 67%); hypotonia (54%); behavioural/psychiatric issues (most frequently autistic spectrum disorder, 51%); kyphoscoliosis (33%) and afebrile seizures (22%). One individual was diagnosed with acute myeloid leukaemia in teenage years. Based upon the results from this study, we present our current management for individuals with TBRS.

A flow cytometric approach to engineering Escherichia coli for improved eukaryotic protein glycosylation.

A synthetic pathway for production of the eukaryotic trimannosyl chitobiose glycan (mannose3-N-acetylglucosamine2, Man3GlcNAc2) and its transfer to specific asparagine residues in target proteins was previously engineered in Escherichia coli, providing this simple microbe with the ability to perform a complex post-translational protein modification. Here, we leveraged a flow cytometric fluorescence-based assay to improve Man3GlcNAc2 glycan biosynthesis in E. coli cells. Specifically, pathway improvements were identified, including reducing pathway enzyme expression levels and overexpressing nucleotide sugar biosynthesis genes, which enhanced production of lipid-linked Man3GlcNAc2 by nearly 50-fold to 13.9 µg/L. In turn, cells producing higher levels of the Man3GlcNAc2 substrate yielded up to 10 times more glycosylated acceptor protein (to ~ 14 mg/L) than their non-optimized counterparts. These results demonstrate the use of flow cytometry screening as a powerful tool for interrogating the surfaces of glyco-engineered bacteria and identifying meaningful improvements in glycan biosynthesis. We anticipate this approach will enable further optimization of bacterial glycan biosynthesis pathways using new strain engineering tools from metabolic engineering and synthetic biology.

Manipulation of dipeptidylpeptidase 10 in mouse and human in vivo and in vitro models indicates a protective role in asthma.

We previously identified dipeptidylpeptidase 10 (DPP10) on chromosome 2 as a human asthma susceptibility gene, through positional cloning. Initial association results were confirmed in many subsequent association studies but the functional role of DPP10 in asthma remains unclear. Using the MRC Harwell N-ethyl-N-nitrosourea (ENU) DNA archive, we identified a point mutation in Dpp10 that caused an amino acid change from valine to aspartic acid in the ß-propeller region of the protein. Mice carrying this point mutation were recovered and a congenic line was established (Dpp10145D ). Macroscopic examination and lung histology revealed no significant differences between wild-type and Dpp10145D/145D mice. However, after house dust mite (HDM) treatment, Dpp10 mutant mice showed significantly increased airway resistance in response to 100 mg/ml methacholine. Total serum IgE levels and bronchoalveolar lavage (BAL) eosinophil counts were significantly higher in homozygotes than in control mice after HDM treatment. DPP10 protein is present in airway epithelial cells and altered expression is observed in both tissue from asthmatic patients and in mice following HDM challenge. Moreover, knockdown of DPP10 in human airway epithelial cells results in altered cytokine responses. These results show that a Dpp10 point mutation leads to increased airway responsiveness following allergen challenge and provide biological evidence to support previous findings from human genetic studies. This article has an associated First Person interview with the first author of the paper.

A role for core planar polarity proteins in cell contact-mediated orientation of planar cell division across the mammalian embryonic skin.

The question of how cell division orientation is determined is fundamentally important for understanding tissue and organ shape in both healthy or disease conditions. Here we provide evidence for cell contact-dependent orientation of planar cell division in the mammalian embryonic skin. We propose a model where the core planar polarity proteins Celsr1 and Frizzled-6 (Fz6) communicate the long axis orientation of interphase basal cells to neighbouring basal mitoses so that they align their horizontal division plane along the same axis. The underlying mechanism requires a direct, cell surface, planar polarised cue, which we posit depends upon variant post-translational forms of Celsr1 protein coupled to Fz6. Our hypothesis has parallels with contact-mediated division orientation in early C. elegans embryos suggesting functional conservation between the adhesion-GPCRs Celsr1 and Latrophilin-1. We propose that linking planar cell division plane with interphase neighbour long axis geometry reinforces axial bias in skin spreading around the mouse embryo body.