American Journal of Physiology-Lung Cellular and Molecular Physiology

BackgroundChronic obstructive pulmonary disease (COPD) is a chronic lung condition characterised by accelerated lung aging. Extracellular vesicles (EVs), which can be categorised into large EVs (LEVs) and small EVs (SEVs), may play a critical role in intercellular communication. They contribute to the pathogenesis of COPD by transporting and transferring microRNAs (miRNAs). This study profiles cells and EV-associated miRNAs from both healthy and COPD small airway (SA)-epithelial cells and SA-fibroblasts and identifies the biological pathways associated with these miRNAs. MethodsEVs were isolated from conditioned media of healthy and COPD SA-epithelial cells and SA-fibroblasts, both at baseline and following H2O2 exposure. MiRNAs were extracted from cells and EVs and analysed by small RNA (smRNA) sequencing. ResultsSmRNA sequencing of COPD SA-epithelial cells and EVs revealed that four miRNAs were upregulated and fourteen were downregulated in the cells compared to healthy controls. COPD LEVs displayed nine upregulated and ten downregulated miRNAs, while SEVs showed ten upregulated and eleven downregulated miRNAs. Only one miRNA consistently upregulated in COPD SA-epithelial cells, LEVs, and SEVs. The various differentially expressed miRNAs were primarily associated with cellular senescence pathways. In SA-fibroblasts 39 miRNAs were upregulated in COPD compared to healthy cells. 14 miRNAs were upregulated in COPD LEVs and 11 downregulated, whereas SEVs exhibited twenty upregulated and eleven downregulated miRNAs. Overlap was limited, with only three miRNAs consistently upregulated in SA-fibroblasts and EVs. These miRNAs were linked to pathways related to fibrosis and cellular senescence. Furthermore, oxidative stress alters the miRNA profiles detected in cells and EVs differently between cells from healthy individuals and COPD patients. ConclusionsCOPD alters miRNA signatures in cells and their EVs, with limited overlap between compartments. These COPD-associated miRNAs are enriched in pathways driving cellular senescence and fibrosis, suggesting a potential role in disease progression.

BackgroundLung ischemia-reperfusion (IR) injury drives early morbidity after lung transplantation and cardiothoracic surgery, yet targeted preventive therapies are lacking. The gut-lung axis and microbiota-derived tryptophan metabolites, including indole-3-propionate (IPA), may regulate pulmonary immunity and inflammation. We investigated whether a tryptophan-rich (Trp-Rich) diet attenuates sterile lung IR injury by increasing microbiota-derived indole metabolites and reprogramming alveolar macrophage (AM) inflammatory responses. MethodsC57BL/6 mice received isocaloric tryptophan-standard (Trp-Std; 0.18%) or Trp-Rich (0.60%) diets for 14 days, then underwent unilateral left lung IR (60 min ischemia followed by 60 min reperfusion). Oxygen saturation, lung cytokines, and aryl hydrocarbon receptor (AhR) signaling readouts (Cyp1a1/Cyp1b1) were evaluated. Gut microbiota was profiled by 16S rRNA sequencing, and targeted metabolomics quantified tryptophan metabolites in feces, portal vein (PV) plasma, and lung tissue. To further assess inflammatory priming in vivo, mice were additionally challenged with intratracheal lipopolysaccharide (LPS). Mechanistic studies compared IPA with related indole metabolites in MH-S cells and primary human AMs, including ex vivo nutritional IR, LPS stimulation, and AhR stimulation and blockade using synthetic agonists and antagonists. ResultsTrp-Rich feeding improved post-IR oxygenation, reduced lung IL-1{beta}, and increased pulmonary Cyp1a1/Cyp1b1 gene expression. Trp-Rich diet remodeled the gut microbiota, including enrichment of Bifidobacterium and Lactobacillus, and increased IPA levels across feces, PV plasma, and lung tissue, with lower kynurenine/IPA ratios across matrices. In the LPS intratracheal challenge, Trp-Rich feeding reduced IL-6 levels in lung tissue and systemic plasma. Primary murine AMs isolated from Trp-Rich mice also showed reduced IL-1{beta} and IL-6 release in an ex vivo nutritional IR model. Among tested indole metabolites, IPA showed the strongest dose-dependent suppression of LPS-induced cytokines and chemokines in MH-S cells and primary human AMs, remained active in the ex vivo nutritional IR model, and its anti-inflammatory effect was abrogated by AhR blockade and enhanced by co-treatment with other indole metabolites. ConclusionsA Trp-Rich diet attenuated sterile lung IR injury, coinciding with gut microbiota remodeling, increased systemic and pulmonary IPA, reduced inflammatory priming, and reprogrammed AM responses. These data support diet- or microbiome-directed strategies targeting IPA-AhR signaling to mitigate perioperative lung IR injury. Caption for graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=190 SRC="FIGDIR/small/714281v1_ufig1.gif" ALT="Figure 1"> View larger version (67K): org.highwire.dtl.DTLVardef@1b06a9corg.highwire.dtl.DTLVardef@1273f33org.highwire.dtl.DTLVardef@1a63a2borg.highwire.dtl.DTLVardef@350e1c_HPS_FORMAT_FIGEXP M_FIG A tryptophan-rich diet remodels the gut microbiota and indole metabolite profiles, including IPA, enhances alveolar macrophage AhR signaling, and attenuates sterile lung ischemia-reperfusion injury. C_FIG

BackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease characterized by aberrantly activated, apoptosis-resistant profibrotic lung (myo)fibroblasts. Prior research has demonstrated that lung fibroblasts from patients with IPF exhibit resistance to DNA damage, suggesting that this behavior contributes to their persistent survival and continuous proliferation. We propose that elevated levels of the DNA damage repair protein RAD51 regulate myofibroblast activation and apoptosis and provide a potential therapeutic target to impede fibrosis progression. MethodsHuman lung fibroblasts were transfected with siRNA against RAD51 or treated with RAD51-specific inhibitor B02 and markers of fibrosis, DNA damage, apoptosis, metabolic reprogramming, and mitochondrial dynamics were assessed. The preclinical efficacy of B02 was evaluated in human precision cut lung slices (PCLS) and in a mouse model of pulmonary fibrosis. FindingsRAD51 expression was significantly upregulated in the lungs and lung fibroblasts of IPF patients. Knockdown or inhibition of RAD51 in fibroblasts reduced profibrotic marker expression, suppressed mTORC1 signaling and mitochondrial function, and increased apoptosis susceptibility. Pharmacological inhibition of RAD51 shifted the profibrotic phenotype towards a fibrosis-resolving state in human and mouse PCLS, and in a bleomycin-induced mouse model of lung fibrosis. InterpretationThe inhibition of RAD51 exerts therapeutic benefits in lung fibrosis by promoting apoptosis. Our findings identify that inhibiting RAD51 with B02 in fibroblasts impairs DNA repair and induces metabolic reprogramming, making it a potential therapeutic target. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSPulmonary fibrosis (PF) is characterized by excessive fibroblast activation and subsequent deposition of extracellular matrix (ECM) proteins, which ultimately disrupt normal lung architecture. A significant contributing factor to the pathogenesis of pulmonary fibrosis is the presence of fibroblasts that are resistant to apoptosis, preventing normal wound healing. Recent studies highlight the DNA repair protein RAD51 as effective in protecting fibroblasts from death induced by chemotherapy and ionizing radiation. These finding suggested that RAD51 could have a role in fibroblast activation and apoptosis resistance in pulmonary fibrosis. Added value of this studyWe demonstrated that RAD51 is important for maintaining apoptosis-resistant fibrotic fibroblasts and their metabolic abnormalities. Our findings indicated that TGF{beta}-mediated upregulation of RAD51 reduces DNA damage, activates multiple pathways related to fibroblast activation and proliferation, and induces metabolic reprogramming, ultimately regulating apoptosis. Mechanistically, RAD51 inhibition enhanced p53 acetylation at lysine 120 and upregulated the expression proapoptotic proteins PUMA/BAK in mitochondria, promoting apoptosis. Pharmacological inhibition of RAD51 using the specific inhibitor B02 during the fibrotic phase of experimental lung disease effectively ameliorated pulmonary fibrosis. Implications of all the available evidenceOur findings establish that RAD51 plays an important role in the survival of apoptosis-resistant fibrotic fibroblasts. We propose that reducing RAD51 expression leads to the metabolic reprogramming of activated fibroblasts, resulting in decreased mitochondrial respiration, reduced ATP levels, and diminished glycolysis or glutaminolysis. These observations suggest that targeting energy metabolism through RAD51 inhibition could be a viable strategy to enhance apoptosis, thereby creating a therapeutically targetable pathway in fibrotic cells. These findings highlight the potential of RAD51 as a therapeutic target for the treatment of IPF.

To explore the mechanism of Hsa_circ_0000629 adsorbing miR-212-5p/ nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) through sponge in bronchial asthma. Twenty BALB/C mice were randomly divided into a normal control group and an asthma group. Pathological changes in lung tissue were observed via HE staining. Human bronchial epithelial cells (16HBE) were transfected with Hsa_circ_0000629 overexpression group (Hsa_circ_0000629-over), Hsa_circ_0000629 siRNA (Hsa_circ_0000629-si), mimic NC, miR-212-5p mimic, inhibitor NC, miR-212-5p inhibitor, and LPS+Hsa_circ_0000629 si. LPS-induced asthmatic cell models (LPS group) and untransfected 16HBE cells (NC group) served as controls. qRT-PCR was used to measure Hsa_circ_0000629, miR-212-5p and NLRP3 expression. ELISA assessed interleukin 18 (IL-18), interleukin 1{beta} (IL-1{beta}), interleukin 6 (IL-6) and tumor necrosis factor - (TNF-) levels. Cell proliferation and the apoptosis were evaluated by EDU assay and flow cytometry, respectively. Western blot analyzed Cleaved-caspase 1, 3 and 9 proteins expression. Dual-luciferase assay verified the binding sites of Hsa_circ_0000629 to miR-212-5p and NLRP3 to miR-212-5p. HE staining revealed inflammatory cell infiltration, bronchial wall thickening, smooth muscle hyperplasia, and alveolar destruction in asthmatic mice. Compared with the controls, Hsa_circ_0000629 and NLRP3 expression were significantly increased, while miR-212-5p expression was decreased in asthmatic lung tissues. In 16HBE cells, Hsa_circ_0000629-over and LPS groups showed elevated Hsa_circ_0000629 and NLRP3 expression but reduced miR-212-5p levels. Silencing Hsa_circ_0000629 in LPS-treated cells (LPS+Hsa_circ_0000629-si) reversed these effects. Overexpression of miR-212-5p counteracted Hsa_circ_0000629-induced NLRP3 upregulation, while miR-212-5p inhibition enhanced NLRP3 expression. LPS exposure increased TNF-, IL-18, IL-6, and IL-1{beta} levels, reduced cell proliferation, and promoted apoptosis. These changes were attenuated by Hsa_circ_0000629 silencing or miR-212-5p overexpression. Western blot confirmed that Hsa_circ_0000629 overexpression upregulated Cleaved-Caspase 1, 3, and 9, whereas miR-212-5p mimic or Hsa_circ_0000629-si reversed this trend. Dual-luciferase assays demonstrated targeted interactions among Hsa_circ_0000629, miR-212-5p, and NLRP3. Interference with Hsa_circ_0000629 expression can alleviate LPS induced apoptosis in 16HBE cells and inhibit the expression of inflammatory factors by targeting the miR-212-5p/NLRP pathway, which may be a new target for the treatment of asthma.

Right ventricular failure (RVF) is a serious disease with a high mortality but no effective pharmacologic treatments. We reported RVF was reversed by chronic treatment with an 1A-adrenergic receptor (1A-AR) agonist. Recent studies suggest mitochondrial dysfunction contributes to RVF. Therefore, we investigated if reversal of RVF by chronic 1A-AR agonist treatment involved improved mitochondrial function. A mouse model of RVF caused by pulmonary artery constriction (PAC) for 2 wk was chronically treated for a further 2 wk. with a low dose of the 1A-AR agonist A61603 (10 ng/kg/day) or vehicle (no drug control). RV dysfunction was assessed from the fractional shortening of the RV outflow tract (RVOT FS). RVOT FS for sham controls (46.5 {+/-} 1.3 %, n = 9) was reduced 4 wk after PAC (27.6 {+/-} 1.5 %, n = 13, P < 0.0001), but was higher after PAC plus 2 wk A61603 treatment (34.5 {+/-} 0.6 %, n = 14, P < 0.001). RV myocardial respiration rate (O2 consumption) for sham controls (776 {+/-} 51 pM/s/mg, n = 9) was reduced 4 wk after PAC (493 {+/-} 28 pM/s/mg, n = 15, P <0.0001), but was higher after PAC plus 2 wk A61603 treatment (634 {+/-} 30 pM/s/mg, n = 11, P <0.05). RV myocardial ATP level for sham controls (3.3 {+/-} 0.1 mM, n = 10) was reduced 4 wk after PAC (1.9 {+/-} 0.1 mM, n = 6, P < 0.0001), but was higher after PAC plus 2 wk A61603 treatment (2.6 {+/-} 0.13 mM, n = 7, P < 0.01). In conclusion, reversal of RVF after chronic A61603 treatment involved reversal of mitochondrial dysfunction. Consistent with our previous studies, this study suggests that the 1A-AR is a therapeutic target to treat RVF. HighlightsRV failure is reported to involve mitochondrial dysfunction which might impair RV contraction by decreasing cardiomyocyte ATP level. Using the pulmonary artery constriction model of RV failure, we found that chronic treatment with an 1A-adrenergic receptor agonist increased RV myocardial respiration rate, increased RV myocardial ATP level, and increased RV function. These findings suggest that the 1A-adrenergic receptor is a therapeutic target for treating RV failure, and that the mechanism involves improved RV cardiomyocyte bioenergetic status.

KMT2D, the histone methyltransferase and core component of the COMPASS/MLL4 complex, has been implicated in developmental diseases such as Kabuki Syndrome, interstitial lung disease, and congenital diaphragmatic hernia, with clear links to pediatric pulmonary disorders. Despite this, the mechanism by which KMT2D governs lung development remains unclear. Knock-in mouse models rendering, KMT2D catalytically deactivated (KMT2DKI) and reducing H3K4 methylation, have demonstrated potential in defining KMT2Ds role in pulmonary development. Our examination of the lungs of KMT2DKI mice revealed increased cellular density and impaired sacculation indicated by reduced airspace chord length, thickening of intersaccular septa, and abnormal alveolar cell differentiation. KMT2DKI mice revealed narrowed Sox2+ conducting airways and epithelial differentiation defects characterized by reduced Cc10+ club cells. Accompanying the alveolar and airway hypoplasia, blood vessel luminal area was reduced. Conversely, KMT2DKI lungs had a significantly higher proportion of proliferating cells accompanied by a dramatic expansion in Pdgfr+ mesenchymal progenitor cells. Our findings therefore suggest that KMT2D-mediated H3K4 methylation is vital to normal lung development, and its impairment results in widespread pulmonary hypoplasia and potentially pulmonary hypertension.

Equine asthma (EA) is a highly prevalent, chronic, inflammatory disease of the lower airways ranging from mild-to-moderate to severe clinical presentations. Diagnosis currently relies on bronchoalveolar lavage fluid (BALF) cytology, an invasive method associated with interobserver variability, which highlights the need for more reproducible approaches. MicroRNAs (miRNAs) are small noncoding RNAs involved in post-transcriptional gene regulation. They are stable and readily detectable in body fluids and have shown promising results as biomarkers in human asthma. The aim of this study was to characterize miRNA abundance profiles in BALF and serum from horses with distinct EA endotypes to evaluate their biomarker potential and explore their involvement in disease pathogenesis. A total of 43 horses were included and classified as either EA (n=32) or controls (n=11), based on clinical examination and BALF cytology. The EA horses were further divided into three endotypes based on BALF inflammatory cell composition: neutrophilic asthma (n=10), mastocytic asthma (n=15), and mixed asthma (n=7). RNA was isolated from both serum and BALF samples and analyzed by quantitative real-time PCR (qPCR) targeting 103 miRNAs linked to asthma and pulmonary inflammation in humans. Differential miRNA abundance was analyzed across EA endotypes. The most significantly differentially abundant miRNAs were used for in silico target prediction and pathway enrichment analyses. Horses with mixed EA had significantly lower levels of eca-miR-125a-3p and eca-miR-125b-5p in BALF compared to controls. Additionally, eca-miR-146a-5p abundance was significantly increased in BALF from horses with neutrophilic EA compared to mastocytic EA. Target and pathway enrichment analyses for eca-miR-146a-5p identified immune-relevant pathways, such as MAPK and T-cell receptor signaling, supporting its involvement in inflammatory processes associated with asthma. This study identified three promising candidates, eca-miR-125a-3p, eca-miR-125b-5p, and eca-miR-146a-5p, as potential biomarkers associated with different EA endotypes. These miRNAs are interesting candidates for further investigation in an independent cohort.

Background: Diets with high inflammatory potential may contribute to asthma and impaired lung function, yet evidence from Asian populations is limited. Objective: We aimed to examine the association between the energy-adjusted Dietary Inflammatory Index (E-DII) and lung function in Korean adults, stratified by asthma status. Methods: Data were analyzed from 12,400 participants in the Korea National Health and Nutrition Examination Survey (2016-2018). The E-DII was calculated from 24-hour dietary recall using 21 validated food parameters. Lung function (FEV1, FVC) was measured by standardized spirometry, and current asthma was defined as both a physician diagnosis and the presence of current symptoms. Multivariable logistic and linear regression models adjusted for potential confounders were applied. Results: Higher E-DII scores were significantly associated with increased asthma prevalence and lower lung function. Notably, the magnitude of the association between E-DII and FEV1 % predicted was markedly stronger in the asthma group (beta = -0.613) than in the non-asthma group (beta = -0.147). This disparity suggests that individuals with pre-existing airway inflammation may be more susceptible to the adverse effects of a pro-inflammatory diet. Conclusions: A pro-inflammatory diet is associated with higher asthma risk and reduced lung function in Korean adults, with more pronounced effects observed in those with asthma. Dietary interventions targeting reduced systemic inflammation may be beneficial for respiratory health management.

AbstractInflammation and oxidative stress are key drivers in the pathogenesis of chronic lung diseases, including asthma, pulmonary fibrosis, and chronic obstructive pulmonary disease. Extracellular vesicles derived from the marine microalga Tetraselmis chuii, referred to as nanoalgosomes, have recently gained attention as natural nanocarriers that possess inherent antioxidant and anti-inflammatory properties. In this study, we investigated the biocompatibility and protective effects of aerosolized nanoalgosomes in a bronchial epithelial-macrophage co-culture model at the air-liquid interface. Co-cultures of CALU-3 epithelial cells and differentiated THP-1 macrophages were primed with aerosolised nanoalgosomes and subsequently exposed to either oxidative stress (tert-butyl hydroperoxide) or an inflammatory stimulus (lipopolysaccharide; LPS). Epithelial barrier integrity and cytotoxicity were evaluated using transepithelial electrical resistance and lactate dehydrogenase release assays, respectively, while intracellular reactive oxygen species levels and cytokine secretion were measured to assess antioxidant and immunomodulatory responses. Nanoalgosomes were non-cytotoxic, preserved epithelial barrier integrity, and significantly reduced oxidative stress. In addition, nanoalgosomes priming attenuated LPS-induced secretion of pro-inflammatory cytokines (IL-1{beta}, IL-6, IL-8, IL-18, TNF-) as well as the anti-inflammatory cytokine IL-10, suggesting a balanced immunomodulatory response. Overall, aerosolized nanoalgosomes maintained epithelial homeostasis and mitigated both oxidative and inflammatory stress, underscoring their potential as a safe, sustainable, and effective therapeutic strategy for chronic inflammatory lung diseases. Given their natural origin, excellent biocompatibility, and suitability for aerosol delivery, nanoalgosomes represent a promising class of inhalable biotherapeutics.

Resolution of fibrosis following lung injury is distinguished from persistent/progressive parenchymal scarring through the timely clearance of aberrant cell types, removal of excess collagens, and regeneration of alveolar structure. The requisite signaling pathways, cellular cross-talk, and phenotypic shifts associated with, and required for, resolution of established lung fibrosis have not been well characterized. To address this critical knowledge gap, we performed longitudinal single-cell RNA sequencing of whole mouse lung digests obtained during spontaneously resolving fibrosis. We observed a putatively pro-fibrotic macrophage population emerge during peak fibrosis and undergo partial clearance during resolution. Our study also revealed conspicuous shifts in well-established pathways associated with tissue repair and fibrosis among immune, mesenchymal, and epithelial cells during spontaneous resolution. In addition to a decline in pro-fibrotic driver pathways, the putative anti-fibrotic pathways cAMP, HGF/MET, and TWEAK were enriched in several cell types during spontaneous resolution. CellChat analysis was used to predict the cellular senders and recipients of each pathway and characterize their longitudinal changes. Our characterization of the cellular and molecular dynamics in whole lungs during spontaneous fibrosis resolution provides a foundation for the identification of endogenous pathways that might be leveraged to treat pulmonary fibrosis.

BackgroundThe COVID-19 pandemic exposed critical shortages of mechanical ventilators, particularly in low-resource settings. Disruptions in global supply chains and dependence on specialized components highlighted the need for scalable, locally manufacturing alternatives for emergency respiratory support. AimTo describe and evaluate a simplified, supply-chain-independent mechanical ventilator assembled from widely available automotive and simple hardware components, and intended as a last-resort solution. MethodsThe ventilator is based on a reciprocating air pump driven by an automotive windshield wiper motor coupled to parallel shaft bellows and readily assembled passive membrane valves, only requiring materials available from standard hardware retailers, minimal tools, and basic manual skills. Ventilator performance was assessed through bench testing using a patient model simulating severe lung disease in an adult (R=20 cmH2O{middle dot}s/L, C=15 mL/cmH2O) and pediatric (R=50 cmH2O{middle dot}s/L, C=10 mL/cmH2O) patients. Realistic proof of concept was performed in four mechanically ventilated 50-kg pigs. ResultsThe device delivered tidal volumes up to 600 mL and respiratory rates up to 45 breaths/min with PEEP up to 10 cmH2O, covering pediatric and adult ventilation ranges. In vivo testing showed that the ventilator maintained arterial blood gases within the targeted range. Technical details for ventilator construction are provided in an open-source video tutorial. DiscussionThis low-cost ventilator demonstrated adequate performance under demanding conditions. Although not a substitute for commercial intensive care ventilators, its simplicity, autonomy, and independence from fragile supply chains provide a potentially life-saving option in resource-constrained emergency scenarios.

General anesthetics enable invasive experimentation but can affect cardiovascular and respiratory physiology, biasing preclinical outcomes. We compared five anesthetic regimens in adult male Wistar rats, tribromoethanol (TBE, 250 mg/kg i.p.), chloral hydrate (CH, 400 mg/kg i.p.), ketamine-xylazine (KX, 80/10 mg/kg i.p.), thiopental (TP, 80 mg/kg i.p.), and isoflurane (ISO, 4% induction, 2% maintenance), to investigate integrated cardiorespiratory and biochemical markers. Femoral arterial catheterization allowed continuous blood pressure (BP) and derived heart rate (HR) recordings, while ventilation was assessed through pletysmography at baseline (awake), during induction, and recovery phases of anesthesia. Variability was evaluated in the time and frequency domains, including HR, systolic blood pressure (SBP), and spontaneous baroreflex sensitivity. In an independent cohort of rats, butyrylcholinesterase (BChE), CK-MB, cTnI, and LDH were measured. Baseline BP was unchanged by TBE and TP, whereas all anesthetics affected HR. Minute ventilation and breathing frequency were reduced with all agents, while tidal volume decreased with KX and TBE only. LDH and cTnI were unaffected, BChE was reduced by KX, TBE, and ISO, and CK-MB increased with CH and KX. Variability analysis showed that all anesthetics depressed pulse-interval and SBP variability and shifted spectral power toward higher frequencies, while baroreflex sensitivity and effectiveness were consistently reduced. During recovery, KX and TP restored most variability indices, whereas CH, TBE, and ISO showed persistent suppression. These findings highlight distinct profiles of cardiovascular depression and biomarker responses across anesthetics and underscore the importance of accounting for autonomic variability when selecting different anesthetics in experimental protocols. HighlightsO_LIFive anesthetic regimens were tested in rats. C_LIO_LIAll anesthetics reduced ventilation, and KX and TBE also reduced tidal volume. C_LIO_LICH and KX increased CKMB, while KX, TBE and ISO reduced BChE. C_LIO_LIAll anesthetics reduced blood pressure variability and baroreflex sensitivity. C_LIO_LIVariability recovered with TP and KX, whereas CH, TBE and ISO showed persistent suppression. C_LI

"Dry Hitting" is a unique phenomenon of e-cigarette use that has been shown to produce toxic chemical degradants and byproducts. Although it is widely understood that nicotine exposure during adolescence impacts neurobiological and behavioral function, little is known about how dry hitting may impact users. We hypothesized that subjects repeatedly exposed to nicotine dry hit vapor would exhibit distinct behavioral responses compared with saturated nicotine vapor and would differentially alter the expression of perineuronal nets (PNNs) in the rodent brain. Using a customized system of e-cigarette vapor inhalation, adolescent male Wistar rats (PND 31-40) received vaporized nicotine (30 or 60 mg/mL; [~]2.5-3 mL/cage), nicotine with dry hits (60 mg/mL; 1.75-2 mL/cage), or propylene glycol (PG) vehicle for 30 minutes over 7 daily sessions. Locomotor activity, antinociception, and elevated plus maze testing were used to assess behavioral response to drug intoxication and tolerance. Immunohistochemistry was used to identify Wisteria Floribunda Agglutinin (WFA)-positive PNN structures in the amygdala and insular cortex. Rats exposed to dry hits exhibited behavioral responses (locomotor sensitization, antinociception) similar to those of rats exposed to saturated nicotine vapor, but spent more time in the open arms of the elevated plus maze. Immunohistochemical analyses confirmed significantly greater WFA intensity in the central nucleus of the amygdala, but not the basolateral amygdala or insular cortex, of rats exposed to dry hits. Overall, these data confirm the impact of dry hit vapor on behavioral responses and perineuronal net expression in rats during adolescence.

Staphylococcus aureus is the most common bacterial pathogen affecting pediatric patients with Cystic fibrosis (CF), a genetic disorder that causes thick mucus buildup in the lungs, providing a scaffold for chronic infections. Antibiotic treatment is typically guided by standard in vitro antimicrobial susceptibility testing (AST) in Mueller-Hinton broth (MHB), which does not represent the infection site in CF lungs. Notably, discordances between AST predictions and antibiotic therapeutic outcomes were reported in up to 50% of CF cases. To address this gap, we conducted ASTs against methicillin-resistant S. aureus (MRSA) in CF sputum-mimetic media compared with MHB, demonstrating [&ge;]4-fold discordances across four of nine antibiotic classes. Most significantly, we observed unexpected {beta}-lactam sensitization of MRSA strains (up to 128-fold) in CF sputum-like media, crossing the CLSI clinical breakpoint, suggesting this shift may alter therapeutic outcomes. Genome-wide screens and follow-up assays revealed underlying cell envelope remodelling and alterations to cell envelope stress responses. On the other hand, mucin binding to daptomycin may have led to an apparent 8-fold increase in resistance to this antibiotic in one of the CF sputum-like media. Overall, our AST results in CF sputum-mimetic conditions provide insights into bacterial responses during CF infections. Importantly, they suggest {beta}-lactams may be effective in treating MRSA infections in CF patients, warranting further investigation in relevant in vivo systems.

This study aimed to investigate the dynamics of gene expression in pigs during heat stress (HS), focusing on both short-term (STHA) and long-term (LTHA) heat acclimation phases. A total of 12 castrated males were exposed to thermoneutral temperatures (24{degrees}C) for 14 days (TN) and then to a constant temperature of 30{degrees}C for 21 days. Rectal temperature measurements indicated a biphasic thermoregulatory response, with an initial peak followed by acclimation. Using whole blood transcriptome analysis at seven time points between day 5 before the initiation of HS challenge and day 13 post HS. A total of 525 genes were differentially expressed during the STHA (day 0-day 2) phase. A switch in the expression of most genes was observed around 20 hours after HS. Functional pathway enrichment analysis identified through shape-based clustering revealed the activation of the immune system, especially mediated through toll-like receptor signaling pathways. The LTHA phase (day 2-day 13) revealed 985 differentially expressed genes, with pathways associated with various metabolisms, including mitochondrial fatty acid beta-oxidation, and electron transport, ATP synthesis, and heat production by uncoupling proteins. Interestingly, oxidative phosphorylation was predicted to be activated during the LTHA, particularly in Complex V, whereas other complexes showed mixed regulation. Comparative pathway analysis indicated distinct metabolic adaptations between STHA and LTHA, with up-regulation of glucose and lipid metabolism in late STHA and down-regulation of lipid metabolism during LTHA. This study contributes to a better understanding of the time course of adaptation mechanisms in pigs to HS, underlying a coordinated regulation during STHA involving several stress-specific mechanisms (via the HSP) and metabolic variation to help pigs achieve homeothermy.

RationaleBronchopulmonary dysplasia (BPD), the lung disease associated with premature birth, is a significant health problem, often with long-term respiratory consequences. Recent research has highlighted the potential role of the lung and gut microbiome in the development and progression of BPD, yet it is unclear what aspects of the microbiome may contribute to BPD susceptibility. ObjectivesTo comprehensively characterize the lung and gut microbiomes of preterm infants and identify shared microbial taxa that are associated with BPD development. MethodsTracheal aspirate and stool samples were collected from 39 premature infants over the first month of life. To assess the taxonomic microbial composition of the lung and gut, samples were analyzed using shotgun metagenomic sequencing. BPD classification was determined using the National Institute of Child Health and Human Development severity-based definition at 36 weeks postmenstrual age. Measurements and Main ResultsMicrobial communities of the lung and gut were significantly different between infants who went on to develop BPD and those who did not, with an enrichment of skin-associated microbial genera such as Staphylococcus, Corynebacterium, and Cutibacterium in infants who developed BPD. Specifically, Staphylococcus epidermidis was enriched in premature infants who developed BPD and was the most prominent species shared between lung and gut communities. Temporal changes in gut microbial communities co-occurred with feeding practices and antibiotic exposure, suggesting an influence of external factors on microbiome composition. ConclusionsOur findings provide evidence that certain microbial colonization patterns among premature infants are closely associated with the pathogenesis and progression of BPD.

PurposeHyperosmolar stress (HOS) is a major contributor to corneal epithelial cell damage in dry eye disease. We have previously shown that HOS damages mitochondria and impairs cell metabolism in corneal epithelial cells. Small extracellular vesicles (sEVs) are cell-derived lipid envelopes that are present in all body fluids, including tears. Prior studies suggest that sEV release and composition may be linked with changes in cell metabolism. In this study, we tested the effects of HOS on sEV release and composition, and found that sEV cargo may reflect early, underlying changes in dry eye disease. MethodsTelomerase-immortalized human corneal epithelial (hTCEpi) cells were treated with 450 mOsm NaCl for five days to induce chronic HOS. sEVs were isolated using differential centrifugation followed by iodixanol density gradient flotation. Particle number was determined using Nanoparticle Tracking Analysis (NTA). Mass spectrometry was used to assess the sEV proteome, and selected proteins were validated by immunoblot. Proteome pathways were analyzed using KEGG and CORUM. ResultsPathway analysis revealed an increase in metabolic proteins and proteasome components in sEV cargo released from hTCEpi cells exposed to HOS. These proteins were increased more than fourfold in HOS-sEVs. Examination of proteins involved in the endosomal pathway and NTA further confirmed an increase in HOS-sEV release. ConclusionOur findings suggest a potential mechanism whereby corneal epithelial cells exposed to HOS retain proteins involved in maintaining tissue integrity, while simultaneously releasing unneeded proteins involved in cell metabolism. The presence of metabolic proteins in sEVs may serve as early indicators of dry eye disease.

Severe lung injury promotes the ectopic accumulation of basal cells in the alveoli and the presence of these dysplastic epithelial cells are strongly associated with regions of pulmonary fibrosis (PF) in diseased lungs. Recent studies have identified a unique subset of "inflammatory" fibroblasts expressing pro-inflammatory genes, especially cytokines involved in monocyte recruitment, that are also enriched in disease and thought to contribute to the onset and progression of PF. Here we show that these two injury-induced cell types are intricately connected, in that dysplastic basal cells generate diffusible signals to robustly induce the inflammatory phenotype in pulmonary fibroblasts. Capitalizing on transcriptomic analysis, we identify the enriched inflammatory signaling pathways in treated fibroblasts and specifically demonstrate that IL-1 secreted by dysplastic basal cells is responsible for this fibroblastic transformation. IL-1 neutralization in vivo is sufficient to significantly reduce the inflammatory fibroblast burden in regions of alveolar bronchiolization, and the resolution of inflammatory fibroblasts in turn reduces CCR2+ immune cell recruitment to these areas. These results suggest dysplastic basal cells play an indirect role in chronic inflammation and fibrotic remodeling through the induction of a proinflammatory fibroblast phenotype and subsequent recruitment of immune cells, establishing a chronic wound healing microenvironment that prolongs localized pathologic remodeling.

Asthma is a chronic respiratory illness that causes mild to severe inflammation throughout narrowed airways. During allergic airways inflammation, autophagy prevents extensive lung tissue impairment while inducing a protective anti-pathogen response and macrophages in the lung to maintain homeostasis. Previous studies of autophagy genes and asthma have shown an association with variants in ATG5, but a comprehensive analysis of autophagy related genes and asthma has not been performed. Here we utilize summary statistic data generated from a two-stage genome-wide association study (GWAS) of asthma in the UK Biobank. We examined variants in 21 autophagy related genes and found statistically significant associations for 28 variants in two genes in the discovery dataset and nominally significant replication for 16 of these variants, all annotated to ATG4B. This is the first evidence of an association with variants in ATG4B with asthma which provides a novel potential for future drug development.

Purpose: To understand how the Philips PAP device recall affected patient experiences, clinical practice, and health system responses. Methods: From November 2022 to August 2023, we interviewed individuals with OSA, physicians, respiratory therapists and health system leaders. We also received emailed responses from Health Canada. Interviews explored participants' experiences with the recall announcement and communication, their own responses and perceptions of actions taken by others, the overall impact of the recall and suggestions for improving future recall processes. Interviews were analyzed using an inductive thematic approach. Results: We interviewed 47 participants (16 individuals with OSA, 10 physicians, 17 public or private respiratory therapists, five health system leaders). Themes were organized into four domains: recall communication, execution, participant experiences, and the policy and regulatory context. Participants were confused due to inadequate information from Philips throughout the process. The burden of notifying patients and tracing devices mostly fell to healthcare providers and vendors, while replacement efforts were disorganized and frustrating. Individuals with OSA experienced emotional distress over therapy decisions and difficulties navigating the recall. Healthcare providers described moral distress from being unable to support patients adequately, and vendors faced additional logistical and financial strain. While regulatory authorities reported that Philips followed standard procedures, participants expressed a loss of trust in both the manufacturer and oversight systems. Conclusions: Interviews revealed that poor communication and execution of the Philips recall caused confusion, frustration and significant emotional and financial burden. Collaborative, context-specific strategies are required to improve future recalls.