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Emerging evidence suggests that disease vulnerability is expressed throughout the airways, the so-called unified airway hypothesis, but the evidence to support this is predominantly indirect. We sought to establish the transcriptomic profiles of the upper and lower airways and determine their level of similarity irrespective of airway symptoms (wheeze) and allergy. We performed RNA sequencing on upper and lower airway epithelial cells from 63 children with or without wheeze and accompanying atopy, using differential gene expression and gene coexpression analyses to determine transcriptional similarity. We observed approximately 91% homology in the expressed genes between the 2 sites. When coexpressed genes were grouped into modules relating to biological functions, all were found to be conserved between the 2 regions, resulting in a consensus network containing 16 modules associated with ribosomal function, metabolism, gene expression, mitochondrial activity, and antiviral responses through IFN activity. Although symptom-associated gene expression changes were more prominent in the lower airway, they were reflected in nasal epithelium and included IL-1 receptor like 1, prostaglandin-endoperoxide synthase 1, CCL26 , and periostin. Through network analysis we identified a cluster of coexpressed genes associated with atopic wheeze in the lower airway, which could equally distinguish atopic and nonatopic phenotypes in upper airway samples. We show that the upper and lower airways are significantly conserved in their transcriptional composition, and that variations associated with disease are present in both nasal and tracheal epithelium. Findings from this study supporting a unified airway imply that clinical insight regarding the lower airway in health and disease can be gained from studying the nasal epithelium. [ABSTRACT FROM AUTHOR]

Birth prior to term interrupts the normal development of the respiratory system and consequently results in poor respiratory outcomes that persist throughout childhood. The mechanisms underpinning these poor respiratory outcomes are not well understood, but intrinsic abnormalities within the airway epithelium may be a contributing factor. Current evidence suggests that the airway epithelium is both structurally and functionally abnormal after preterm birth, with reports of epithelial thickening and goblet cell hyperplasia in addition to increased inflammation and apoptosis in the neonatal intensive care unit. However, studies focusing on the airway epithelium are limited and many questions remain unanswered; including whether abnormalities are a direct result of interrupted development, a consequence of exposure to inflammatory stimuli in the perinatal period or a combination of the two. In addition, the difficulty of accessing airway tissue has resulted in the majority of evidence being collected in the pre-surfactant era which may not reflect contemporary preterm birth. This review examines the consequences of preterm birth on the airway epithelium and explores the clinical relevance of currently available models whilst highlighting the need to develop a clinically relevant in vitro model to help further our understanding of the airway epithelium in preterm birth. [ABSTRACT FROM AUTHOR]

Background: There is a growing expectation that cell-based therapies will prove effective for a wide range of conditions including lung diseases such as cystic fibrosis. The promise of these therapies will depend largely on effective delivery and engraftment. In this study, in the setting of human lung transplantation, we sought to determine whether exogenous epithelial cells are able to engraft the transplanted organ and if cells of a similar phenotype could be detected in peripheral blood. Methods: Cells obtained from bronchial brushings and peripheral blood were analyzed via dual fluorescent in situ hybridization/fluorescent immunohistochemistry (FISH/IHC), short tandem repeat polymerase chain reaction (STR-PCR) and flow cytometry. Results: In 2 of 3 gender-mismatched patients we observed limited (5.9% to 6.8% by STR-PCR and 3.5% to 4% by FISH/IHC) engraftment of the bronchial epithelium by exogenous epithelial cells. Engrafting cells were CD34− CD15− CD68− c-Kit−, but expressed CXCR4 on the cell surface. Cells with a similar phenotype were also identified in peripheral blood. In 8 patients, at 2 to 66 months post-transplant, 0.57 ± 0.17% of CD14− peripheral blood mononuclear cells were of epithelial lineage. Almost all were CD45+ and most expressed CXCR4 on the cell membrane. Cells of epithelial lineage were also identified in peripheral blood in healthy individuals but in much lower numbers (0.08 ± 0.01%, p < 0.05). Conclusions: Cells of epithelial lineage are detectable in peripheral blood and are able to engraft the bronchial epithelium in humans. Cell numbers are increased in lung transplantation. [Copyright &y& Elsevier]

Ensitrelvir, a 3C-like protease inhibitor, received emergency approval in Japan in November 2022 for treating non-hospitalized patients with mild-to-moderate COVID-19. However, confirmation of its real-world clinical effectiveness is limited. This retrospective study evaluated 18 vaccinated outpatients (15 men; median age, 39.5 years; range, 26–56), treated with a 5-day oral ensitrelvir regimen (375 mg loading dose, followed by 125 mg daily) between December 1, 2022, and January 31, 2023. Nasal swabs were collected on days 0, 3, 6, and 9 for RT-qPCR to assess viral load. Variants were identified by Sanger sequencing, and outcomes were compared to historical controls. Patients were followed for 60 days to monitor for post-acute sequelae of COVID-19 (PASC). Symptoms such as mild fever and sore throat improved rapidly after one day of ensitrelvir treatment, with 66 % of patients recovering within six days. All individuals were infected with the BA.5 Omicron variant. Viral loads, as measured by Ct values, increased significantly from 21.82 at symptom onset to 37.65 b y day 6, with SARS-CoV-2 RNA undetectable in most patients by day 9. Those treated within 48 h of symptom onset showed the viral load reduction. Compared to historical controls, where symptom resolution took 8.5 days, ensitrelvir shortened recovery time to as little as 1.4 days for over 66 % of patients. Ensitrelvir treatment resulted in rapid symptom relief and significant viral load reduction, with no adverse events, viral rebound, or PASC symptoms, demonstrating its potential efficacy and safety. Larger studies are needed for further confirmation. • Ensitrelvir reduces SARS-CoV-2 viral load in real-world clinical data. • Ensitrelvir given within 24 h of symptoms improves viral clearance and symptoms. • The study found no viral rebound, symptom recurrence, or resistance to ensitrelvir. [ABSTRACT FROM AUTHOR]

Biodiesel, a renewable diesel fuel that can be created from almost any natural fat or oil, is promoted as a greener and healthier alternative to commercial mineral diesel without the supporting experimental data to back these claims. The aim of this research was to assess the health effects of acute exposure to two types of biodiesel exhaust, or mineral diesel exhaust or air as a control in mice. Male BALB/c mice were exposed for 2-hrs to diluted exhaust obtained from a diesel engine running on mineral diesel, Tallow biodiesel or Canola biodiesel. A room air exposure group was used as a control. Twenty-four hours after exposure, a variety of respiratory related end point measurements were assessed, including lung function, responsiveness to methacholine and airway and systemic immune responses. Tallow biodiesel exhaust exposure resulted in the greatest number of significant effects compared to Air controls, including increased airway hyperresponsiveness (178.1 ± 31.3% increase from saline for Tallow biodiesel exhaust exposed mice compared to 155.8 ± 19.1 for Air control), increased airway inflammation (63463 ± 13497 cells/mL in the bronchoalveolar lavage of Tallow biodiesel exhaust exposed mice compared to 40561 ± 11800 for Air exposed controls) and indications of immune dysregulation. In contrast, exposure to Canola biodiesel exhaust resulted in fewer significant effects compared to Air controls with a slight increase in airway resistance at functional residual capacity and indications of immune dysregulation. Exposure to mineral diesel exhaust resulted in significant effects between that of the two biodiesels with increased airway hyperresponsiveness and indications of immune dysregulation. These data show that a single, brief exposure to biodiesel exhaust can result in negative health impacts in a mouse model, and that the biological effects of exposure change depending on the feedstock used to make the biodiesel. [Display omitted] • Exhaust characteristics changed significantly between different biodiesel feedstock types. • Different exposure types caused different biological effects. • A single exposure to both ULSD and Tallow biodiesel exhaust induced airway hyperreactivity. • Indications of immune dysregulation were observed after a single exposure to Tallow biodiesel exhaust. [ABSTRACT FROM AUTHOR]

Dysregulated induction of goblet cell differentiation results in excessive production and retention of mucus and is a common feature of several chronic airways diseases. To date, therapeutic strategies to reduce mucus accumulation have focused primarily on altering the properties of the mucus itself, or have aimed to limit the production of mucus-stimulating cytokines. Here we review the current knowledge of key molecular pathways that are dysregulated during persistent goblet cell differentiation and highlights both pre-existing and novel therapeutic strategies to combat this pathology. [ABSTRACT FROM AUTHOR]

To address climate change concerns, and reduce the carbon footprint caused by fossil fuel use, it is likely that blend ratios of renewable biodiesel with commercial mineral diesel fuel will steadily increase, resulting in biodiesel use becoming more widespread. Exhaust toxicity of unblended biodiesels changes depending on feedstock type, however the effect of feedstock on blended fuels is less well known. The aim of this study was to assess the impact of biodiesel feedstock on exhaust toxicity of 20% blended biodiesel fuels (B20). Primary human airway epithelial cells were exposed to exhaust diluted 1/15 with air from an engine running on conventional ultra-low sulfur diesel (ULSD) or 20% blends of soy, canola, waste cooking oil (WCO), tallow, palm or cottonseed biodiesel in diesel. Physico-chemical exhaust properties were compared between fuels and the post-exposure effect of exhaust on cellular viability and media release was assessed 24 h later. Exhaust properties changed significantly between all fuels with cottonseed B20 being the most different to both ULSD and its respective unblended biodiesel. Exposure to palm B20 resulted in significantly decreased cellular viability (96.3 ± 1.7%; p < 0.01) whereas exposure to soy B20 generated the greatest number of changes in mediator release (including IL-6, IL-8 and TNF-α, p < 0.05) when compared to air exposed controls, with palm B20 and tallow B20 closely following. In contrast, canola B20 and WCO B20 were the least toxic with only mediators G-CSF and TNF-α being significantly increased. Therefore, exposure to palm B20, soy B20 and tallow B20 were found to be the most toxic and exposure to canola B20 and WCO B20 the least. The top three most toxic and the bottom three least toxic B20 fuels are consistent with their unblended counterparts, suggesting that feedstock type greatly impacts exhaust toxicity, even when biodiesel only comprises 20% of the fuel. [Display omitted] • Exhaust characteristics changed significantly between different feedstock types. • Cottonseed biodiesel blend exhaust was the most different to commercial diesel. • Biodiesel feedstock type altered exhaust toxicity when making up 20% of the fuel. • Canola biodiesel was the least toxic type tested and Palm and Soy were the most. [ABSTRACT FROM AUTHOR]

The epithelium of asthmatics is characterized by reduced expression of E-cadherin and increased expression of the basal cell markers ck-5 and p63 that is indicative of a relatively undifferentiated repairing epithelium. This phenotype correlates with increased proliferation, compromised wound healing and an enhanced capacity to undergo epithelial–mesenchymal transition (EMT). The transcription factor β-catenin plays a vital role in epithelial cell differentiation and regeneration, depending on the co-factor recruited. Transcriptional programs driven by the β-catenin/CBP axis are critical for maintaining an undifferentiated and proliferative state, whereas the β-catenin/p300 axis is associated with cell differentiation. We hypothesized that disrupting the β-catenin/CBP signaling axis would promote epithelial differentiation and inhibit EMT. We treated monolayer cultures of human airway epithelial cells with TGFβ1 in the presence or absence of the selective small molecule ICG-001 to inhibit β-catenin/CBP signaling. We used western blots to assess expression of an EMT signature, CBP, p300, β-catenin, fibronectin and ITGβ1 and scratch wound assays to assess epithelial cell migration. Snai-1 and -2 expressions were determined using q-PCR. Exposure to TGFβ1 induced EMT, characterized by reduced E-cadherin expression with increased expression of α-smooth muscle actin and EDA-fibronectin. Either co-treatment or therapeutic administration of ICG-001 completely inhibited TGFβ1-induced EMT. ICG-001 also reduced the expression of ck-5 and -19 independent of TGFβ1. Exposure to ICG-001 significantly inhibited epithelial cell proliferation and migration, coincident with a down regulation of ITGβ1 and fibronectin expression. These data support our hypothesis that modulating the β-catenin/CBP signaling axis plays a key role in epithelial plasticity and function. [ABSTRACT FROM AUTHOR]

Background: Long-term survival after lung transplantation is hindered by the development of bronchiolitis obliterans syndrome (BOS), and recent evidence suggests that dysregulated epithelial repair may underlie its development. Because matrix metalloproteinase (MMP) -2 and MMP-9 secretion is integral to repair, we hypothesized that airway epithelial cells from patients with BOS would over-express these matrix-degrading enzymes. Methods: Cells obtained from bronchial and bronchiolar brushings from patients with and without BOS (without acute rejection or infection) were analyzed via quantitative polymerase chain reaction and immunocytochemistry for MMP-2, and MMP-9 gene and protein expression. The expression of tissue inhibitor of metalloproteinase (TIMP)2 and TIMP1 was also assessed. MMP activity in bronchoalveolar lavage was determined via gelatin zymography. Results: MMP-2 and MMP-9 production was significantly higher in bronchoalveolar lavage (3.85- and 11.59-fold, p < 0.001) and airway epithelium (MMP-2 bronchial: 6.33-fold, bronchiolar: 3.57-fold, both p < 0.001; MMP-9 bronchial: 32.55-fold, p < 0.001; bronchiolar: 8.60-fold, p = 0.01) in patients with BOS, but expression in patients without BOS was not different from healthy controls. TIMP expression was similar in patients with and without BOS. Immunostaining confirmed that the airway epithelium was a direct source of MMP-2 and MMP-9 expression in patients with BOS. Conclusion: In patients with BOS, the airway epithelium over-expresses MMPs, even in the absence of acute rejection or infection. Dysregulated epithelial repair may be a key feature of BOS. [ABSTRACT FROM AUTHOR]