Mike O'Sullivan

Under homeostatic conditions, epithelial cells remain non-migratory. However, during embryonic development and pathological conditions, they become migratory. The mechanism underlying the transition of the epithelial layer between non-migratory and migratory phases is a fundamental question in biology. Using well-differentiated primary human bronchial epithelial cells that form a pseudostratified epithelium, we have previously identified that a confluent epithelial layer can transition from a non-migratory to migratory phase through an unjamming transition (UJT). We previously defined collective cellular migration and apical cell elongation as hallmarks of UJT. However, other cell-type-specific changes have not been previously studied in the pseudostratified airway epithelium, which consists of multiple cell types. Here, we focused on the quantifying morphological changes in basal stem cells during the …

ImportanceThe longer-term effects of therapies for the treatment of critically ill patients with COVID-19 are unknown.ObjectiveTo determine the effect of multiple interventions for critically ill adults with COVID-19 on longer-term outcomes.Design, Setting, and ParticipantsPrespecified secondary analysis of an ongoing adaptive platform trial (REMAP-CAP) testing interventions within multiple therapeutic domains in which 4869 critically ill adult patients with COVID-19 were enrolled between March 9, 2020, and June 22, 2021, from 197 sites in 14 countries. The final 180-day follow-up was completed on March 2, 2022.InterventionsPatients were randomized to receive 1 or more interventions within 6 treatment domains: immune modulators (n = 2274), convalescent plasma (n = 2011), antiplatelet therapy (n = 1557), anticoagulation (n = 1033), antivirals (n = 726), and corticosteroids (n = 401).Main Outcomes …

Projections of future carbon sinks and stocks are important because they show how the world's ecosystems will respond to elevated CO2 and changes in climate. Moreover, they are crucial to inform policy decisions around emissions reductions to stay within the global warming levels identified by the Paris Agreement. However, Earth System Models from the 6th Coupled Model Intercomparison Project (CMIP6) show substantial spread in future projections—especially of the terrestrial carbon cycle, leading to a large uncertainty in our knowledge of any remaining carbon budget (RCB). Here we evaluate the global terrestrial carbon cycle projections on a region‐by‐region basis and compare the global models with regional assessments made by the REgional Carbon Cycle Assessment and Processes, Phase 2 activity. Results show that for each region, the CMIP6 multi‐model mean is generally consistent with the …

BackgroundRhinovirus (RV) infection of airway epithelial cells triggers asthma exacerbations, during which airway smooth muscle (ASM) excessively contracts. Due to ASM contraction, airway epithelial cells become mechanically compressed. We previously reported that compressed human bronchial epithelial (HBE) cells are a source of endothelin-1 (ET-1) that causes ASM contraction. Here, we hypothesized that epithelial sensing of RV by TLR3 and epithelial compression induce ET-1 secretion through a TGF-β receptor (TGFβR)-dependent mechanism.MethodsTo test this, we used primary HBE cells well-differentiated in air–liquid interface culture and two mouse models (ovalbumin and house dust mite) of allergic airway disease (AAD). HBE cells were infected with RV-A16, treated with a TLR3 agonist (poly(I:C)), or exposed to compression. Thereafter, EDN1 (ET-1 protein-encoding gene) mRNA expression and …

Rationale Under homeostatic conditions, epithelial cells remain non-migratory. However, during embryonic developmental and pathological processes, epithelial cells become migratory. In welldifferentiated primary human bronchial epithelial cell layers, non-migratory epithelial cells become migratory through an unjamming transition (UJT). We have previously identified the hallmarks of UJT: apical cell elongation and collective cellular migration. These indicate that UJT is driven by intercellular force modulation, but the nature of these forces in pseudostratified epithelia is unknown. Methods Primary human bronchial epithelial cells were cultured in air-liquid interface (ALI) conditions to achieve a well-differentiated, pseudostratified epithelium. Then, the layer was exposed to an unjamming stimulus: compression or irradiation. Both live time-lapse movies and F-actinstained fluorescence images were acquired at 24 …

Rationale Rhinovirus (RV) infections are the most frequent trigger of asthma exacerbations. However, the mechanisms underlying RV-induced bronchoconstriction, the primary cause of asthma symptoms, remain poorly understood. In addition to obstructing airflow, bronchoconstriction compresses airway epithelial cells mechanically. In our published studies mimicking mechanically compressed human bronchial epithelial (HBE) cells, we demonstrated that HBE cells are a source of endothelin-1 (ET-1), which in turn causes airway smooth muscle (ASM) contraction. Here, we hypothesize that RV infection induces TGF-β receptor (TGFβR)-dependent ET-1, causing bronchoconstriction which underlies RV-induced asthma exacerbations. Methods In air-liquid interface culture, well-differentiated HBE cells were infected with RV-A16, treated with a TLR3 agonist (poly (I: C)), or exposed to mechanical compression. We …

Case Presentation: A 35-year-old parturient with a BMI of 38 and pseudotumor cerebri with an LP shunt in situ. Treatment: Following a discussion with her neurosurgical team, a lumbar epidural was sited under ultrasound guidance for labor analgesia. She proceeded to have an uneventful vaginal delivery.Discussion: Pseudotumor cerebri, also known as idiopathic or benign intracranial hypertension has an incidence of 1-2 per 100,000 [1]. It is most prominent in women of childbearing age with an elevated body mass index (BMI). Presentation is characterized by signs of increased intracranial pressure (ICP), including headaches and visual abnormalities when ICP exceeds 20 mmHg [1]. Lumbo-peritoneal (LP) or ventriculoperitoneal (VP) shunts are used to treat patients with intractable headaches, and progressive visual dysfunction in those patients where conservative measures have failed [2].

We read with interest the article by Arrow et al.[1]. It raises a number of interesting points related to the impact of language used by anaesthetists and the potentially negative impact this may have on the patient’s experience and perception of their care. We recognise that while language is important, and efforts must be made to minimise the potentially negative effects of our choice of words, there remains the issue of informed consent. This article may go too far by encouraging more limited descriptions of therapies to patients. By focusing on the minimisation of nocebo, are we potentially embarking on a journey that will see us return to the days of a paternalistic approach to patient care, whereby patients do not fully understand the therapies they are about to receive? Informed consent is a cornerstone of the modern patient experience. An article by Orr et al.[2] and the Association of Anaesthetists’ guidance in relation …

contained all equipment necessary for intubation. Drawsheld planA, BC andD equipment, while draw E contained extra equipment, tape and nasogastric tubes. Due to equipment constraints, one McGrath was placed in the elective theatre and one within the two emergency theatres while the C-MAC was stored centrally. The old DAT was recycled into a stock trolley. New trollies were introduced with real time data collected in the first 10 weeks. Results: Thirty out of 35 staff gave feedback on the planned set-up (9 ODPs and 26 anaesthetists). All agreed that the new trollies would enhance patient safety. Two respondents suggested the addition of an Ambu bag and Water Circuit to aid resuscitation in the delivery room. Seven intubations occurred in the 10-week period post introduction. Feedback from 4 ODPs and 6 anaesthetists highlighted a delay attaining a video laryngoscope in one of the emergency theatres. As …

RATIONALE A hallmark of asthma is aberrant airway remodeling, but the pathogenesis of this remodeling remains to be elucidated. A growing body of evidence suggests that airway remodeling is caused by dysregulated airway epithelial cells, which serve as a source of pathologic mediators. Moreover, pathologic mediators are excessively produced from airway epithelial cells that are compressed in the narrowed airway during bronchospasm. Here we focus upon tenascin C (TNC). TNC is an extracellular matrix (ECM) protein that remodels tissues, is highly expressed in the asthmatic airways, and is differentially overexpressed in mechanically compressed airway epithelial cells. We investigated the mechanisms by which TNC expression and secretion are increased in airway epithelial cells. METHODS Using well-differentiated primary human bronchial epithelial (HBE) cells maintained in air-liquid interface culture …

Continental North America has been found to be a carbon (C) sink over recent decades by multiple studies employing a variety of estimation approaches. However, several key questions and uncertainties remain with these assessments. Here we used results from an ensemble of 19 state‐of‐the‐art dynamic global vegetation models from the TRENDYv9 project to improve these estimates and study the drivers of its interannual variability. Our results show that North America has been a C sink with a magnitude of 0.37 ± 0.38 (mean and one standard deviation) PgC year−1 for the period 2000–2019 (0.31 and 0.44 PgC year−1 in each decade); split into 0.18 ± 0.12 PgC year−1 in Canada (0.15 and 0.20), 0.16 ± 0.17 in the United States (0.14 and 0.17), 0.02 ± 0.05 PgC year−1 in Mexico (0.02 and 0.02) and 0.01 ± 0.02 in Central America and the Caribbean (0.01 and 0.01). About 57% of the new C assimilated by …

ObjectiveObstructive sleep apnea (OSA) exacerbates Parkinson's disease (PD) manifestations including cognitive dysfunction. Both OSA and PD have been associated with inflammation. Brain-derived neurotrophic factor (BDNF) has been implicated in cognitive function. We aimed to investigate inflammatory cytokines and BDNF in relation to OSA and PD symptoms.MethodsIn a prospective observational study, patients with PD underwent overnight polysomnography. Morning serum levels of interleukin (IL)-1β, IL-6, IL-8, TNFα, and BDNF were quantified at baseline (n = 64) and 6 months (n = 38). Outcomes included non-motor and motor standard scores; Montreal Cognitive Assessment (MoCA); and Epworth Sleepiness scale (ESS). Associations were assessed using linear regression, adjusting for age, sex and body mass index.ResultsAt baseline, IL-6 was associated with the Apnea–Hypopnea Index (β = 0.013 …

Added to this, patient, equipment and drug checks are already well established in our practice and, as their study showed, the vast majority of our airway management occurs in the controlled, elective theatre setting [1]. This may reflect the fact that anaesthetists primarily manage airways in a controlled environment set up expressly for airway management. Healthcare providers working in these areas perform airway management less frequently than theatre-based anaesthetists and, therefore, may benefit more from the use of an aide-memoire.[Extracted from the article]Copyright of Anaesthesia is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the …

Aberrant remodeling of the asthmatic airway is not well understood but is thought to be attributable in part to mechanical compression of airway epithelial cells. Here, we examine compression-induced expression and secretion of the extracellular matrix protein tenascin C (TNC) from well-differentiated primary human bronchial epithelial (HBE) cells grown in an air–liquid interface culture. We measured TNC mRNA expression using RT-qPCR and secreted TNC protein using Western blotting and ELISA. To determine intracellular signaling pathways, we used specific inhibitors for either ERK or TGF-β receptor, and to assess the release of extracellular vesicles (EVs) we used a commercially available kit and Western blotting. At baseline, secreted TNC protein was significantly higher in asthmatic compared to non-asthmatic cells. In response to mechanical compression, both TNC mRNA expression and secreted TNC protein was significantly increased in both non-asthmatic and asthmatic cells. TNC production depended on both the ERK and TGF-β receptor pathways. Moreover, mechanically compressed HBE cells released EVs that contain TNC. These data reveal a novel mechanism by which mechanical compression, as is caused by bronchospasm, is sufficient to induce the production of ECM protein in the airway and potentially contribute to airway remodeling.

Under homeostatic conditions, epithelial cells remain non-migratory. However, during embryonic developmental and pathological processes, they become migratory. The mechanism underlying the transition between non-migratory and migratory epithelial cells is a fundamental question of cellular biology. In well-differentiated primary human bronchial epithelial cell layers, non-migratory epithelial cells become migratory through an unjamming transition (UJT). We have previously identified the hallmarks of UJT: apical cell elongation and collective cellular migration. These indicate that UJT is driven by intercellular force modulation, but the nature of these forces in pseudostratified epithelia is unknown. Here, we identify structural characteristics of basal stem cells that are indicative of force generation. During the UJT, basal stem cells elongate and enlarge, and their stress fibers lengthen and align. These morphological changes in basal stem cells correspond to the previously defined hallmarks of the UJT. Moreover, basal cell elongation and stress fiber lengthening precedes apical cell elongation. Together, these structural changes in basal stem cells suggest that in pseudostratified airway epithelium, basal stem cells may be the origin of the traction forces through stress fiber modeling during the UJT.Summary StatementOur image analysis of pseudostratified airway epithelium reveals basal stem cells as the likely source of traction forces driving collective cellular migration during an unjamming transition.

The widespread use of electronic cigarettes (e-cig) is a serious public health concern; however, mechanisms by which e-cig impair the function of airway epithelial cells—the direct target of e-cig smoke—are not fully understood. Here we report transcriptomic changes, including decreased expression of many ribosomal genes, in airway epithelial cells in response to e-cig exposure. Using RNA-seq we identify over 200 differentially expressed genes in air–liquid interface cultured primary normal human bronchial epithelial (NHBE) exposed to e-cig smoke solution from commercial e-cig cartridges. In particular, exposure to e-cig smoke solution inhibits biological pathways involving ribosomes and protein biogenesis in NHBE cells. Consistent with this effect, expression of corresponding ribosomal proteins and subsequent protein biogenesis are reduced in the cells exposed to e-cig. Gas chromatography/mass …

Epithelial tissue can transition from a jammed, solid-like, quiescent phase to an unjammed, fluid-like, migratory phase, but the underlying molecular events of the unjamming transition (UJT) remain largely unexplored. Using primary human bronchial epithelial cells (HBECs) and one well-defined trigger of the UJT, compression mimicking the mechanical effects of bronchoconstriction, here, we combine RNA sequencing data with protein-protein interaction networks to provide the first genome-wide analysis of the UJT. Our results show that compression induces an early transcriptional activation of the membrane and actomyosin network and a delayed activation of the extracellular matrix (ECM) and cell-matrix networks. This response is associated with a signaling cascade that promotes actin polymerization and cellular motility through the coordinated interplay of downstream pathways including ERK, JNK, integrin …

The increased mass of airway smooth muscle (ASM) in the airways of asthmatic patients may contribute to the pathology of this disease by increasing the capacity for airway narrowing. Evidence for the airway epithelium as a participant in ASM remodeling is accruing. To investigate mechanisms by which airway epithelial cells induce ASM cell (ASMC) proliferation, we have employed a co-culture model to explore markers of ASMC proliferative phenotype. Co-culture with epithelial cells led to incorporation of bromodeoxyuridine into ASMCs, indicating augmented proliferation and an associated increase in mRNA of the pro-proliferative co-transcription factor Elk1. Although the mitogen heparin-binding epidermal growth factor (HB-EGF) was augmented in the co-culture supernatant, the ASMC epidermal growth factor receptor (EGFR), an effector of HB-EGF induced proliferation, did not mediate epithelial-induced proliferation. The co-culture increased the expression of ASMC mRNA for the pro-inflammatory cytokines IL-6 and IL-8 as well as the pro-proliferative microRNA miR-210. The transcriptional repressor Max-binding protein (Mnt), a putative target of miR-210, was transcriptionally repressed in co-cultured ASMCs. Together, these data indicate that the airway epithelium-induced proliferative phenotype of ASMCs is not driven by EGFR signaling, but rather may be dependent on miR210 targeting of tumor suppressor Mnt.

The COVID-19 pandemic is an ongoing threat to public health. Since the identification of COVID-19, the disease caused by SARS-CoV-2, no drugs have been developed to specifically target SARS-CoV-2. To develop effective and safe treatment options, a better understanding of cellular mechanisms underlying SARS-CoV-2 infection is required. To fill this knowledge gap, researchers require reliable experimental systems that express the host factor proteins necessary for the cellular entry of SARS-CoV-2. These proteins include the viral receptor, angiotensin-converting enzyme 2 (ACE2), and the proteases, transmembrane serine protease 2 (TMPRSS2) and furin. A number of studies have reported cell-type-specific expression of the genes encoding these molecules. However, less is known about the protein expression of these molecules. We assessed the suitability of primary human bronchial epithelial (HBE …

The COVID-19 pandemic is an ongoing threat to public health. Since the identification of COVID-19, the disease caused by SARS-CoV-2, no drugs have been developed to specifically target SARS-CoV-2. To develop effective and safe treatment options, a better understanding of cellular mechanisms underlying SARS-CoV-2 infection is required. To fill this knowledge gap, researchers require reliable experimental systems that express the host factor proteins necessary for the cellular entry of SARS-CoV-2. These proteins include the viral receptor, angiotensin-converting enzyme 2 (ACE2), and the proteases, transmembrane serine protease 2 (TMPRSS2) and furin. A number of studies have reported cell-type-specific expression of the genes encoding these molecules. However, less is known about the protein expression of these molecules. We assessed the suitability of primary human bronchial epithelial (HBE …