Alveolar Epithelial Cells Type Research Articles

Endothelialized Bronchioalveolar Lung Organoids Model Endothelial Cell Responses to Injury.

Organoid 3D systems are powerful platforms to study development and disease. Recently, the complexity of lung organoid models derived from adult mouse and human stem cells has increased substantially in terms of cellular composition and structural complexity. However, a murine lung organoid system with a clear integrated endothelial compartment is still missing. Here, we describe a novel method that adds another level of intricacy to our published bronchioalveolar lung organoid (BALO) model by microinjection of FACS-sorted lung endothelial cells (ECs) into differentiated organoid cultures. Before microinjection, ECs obtained from the lung homogenate (LH) of young mice expressed typical ECs markers such as CD31 and vascular endothelial (VE)-Cadherin and showed tube formation capacity. Following microinjection, ECs surrounded BALO´s alveolar-like compartment aligning with both alveolar epithelial cells type I (AECI) and type II (AECII), as demonstrated by confocal and electron microscopy. Notably, expression of Car4 and Aplnr was as well detected, suggesting presence of EC microvascular phenotypes in the cultured ECs. Moreover, upon epithelial cell injury by lipopolysaccharides (LPS) and influenza A virus (IV), endothelialized BALO (eBALO) released proinflammatory cytokines leading to the upregulation of the intercellular adhesion molecule 1 (ICAM-1) in ECs. In summary, we characterized for the first time a organoid model that incorporates ECs into the alveolar structures of lung organoids, not only increasing our previous model ́s cellular and structural complexity but also providing a suitable niche to model lung endothelium responses to injury ex vivo.

Bilirubin Exerts Protective Effects on Alveolar Type II Pneumocytes in an In Vitro Model of Oxidative Stress.

Newborn infants face a rapid surge of oxygen and a more protracted rise of unconjugated bilirubin after birth. Bilirubin has a strong antioxidant capacity by scavenging free radicals, but it also exerts direct toxicity. This study investigates whether cultured rat alveolar epithelial cells type II (AEC II) react differently to bilirubin under different oxygen concentrations. The toxic threshold concentration of bilirubin was narrowed down by means of a cell viability test. Subsequent analyses of bilirubin effects under 5% oxygen and 80% oxygen compared to 21% oxygen, as well as pretreatment with bilirubin after 4 h and 24 h of incubation, were performed to determine the induction of apoptosis and the gene expression of associated transcripts of cell death, proliferation, and redox-sensitive transcription factors. Oxidative stress led to an increased rate of cell death and induced transcripts of redox-sensitive signaling pathways. At a non-cytotoxic concentration of 400 nm, bilirubin attenuated oxidative stress-induced responses and possibly mediated cellular antioxidant defense by influencing Nrf2/Hif1α- and NFκB-mediated signaling pathways. In conclusion, the study demonstrates that rat AEC II cells are protected from oxidative stress-induced impairment by low-dose bilirubin.

The expression of the surfactant proteins SP-A and SP-B during postnatal alveolarization of the rat lung.

Surfactant-specific proteins (SP) are responsible for the functional and structural integrity as well as for the stabilization of the intra-alveolar surfactant. Morphological lung maturation starts in rat lungs after birth. The aim of this study was to investigate whether the expression of the hydrophilic SP-A and the hydrophobic SP-B is associated with characteristic postnatal changes characterizing morphological lung maturation. Stereological methods were performed on the light microscope. Using immunohistochemical and molecular biological methods (Western Blot, RT-qPCR), the SP-A and SP-B of adult rat lungs and of those with different postnatal developmental stages (3, 7, 14 and 21 days after birth) were characterized. As signs of alveolarization the total septal surface and volume increased and the septal thickness decreased. The significantly highest relative surface fraction of SP-A labeled alveolar epithelial cells type II (AEII) was found together with the highest relative SP-A gene expression before the alveolarization (3th postnatal day). With the downregulation of SP-A gene expression during and after alveolarization (between postnatal days 7 and 14), the surface fraction of the SP-A labeled AEII also decreased, so they are lowest in adult animals. The surface fraction of SP-B labeled AEII and the SP-B gene expression showed the significantly highest levels in adults, the protein expression increased also significantly at the end of morphological lung maturation. There were no alterations in the SP-B expression before and during alveolarization until postnatal day 14. The protein expression as well as the gene expression of SP-A and SP-B correlated very well with the total surface of alveolar septa independent of the postnatal age. The expression of SP-A and SP-B is differentially associated with morphological lung maturation and correlates with increased septation of alveoli as indirect clue for alveolarization.

6-Gingerol ameliorates alveolar hypercoagulation and fibrinolytic inhibition in LPS-provoked ARDS via RUNX1/NF-κB signaling pathway

BackgroundAlveolar hypercoagulation and fibrinolytic inhibition play a central role in refractory hypoxemia in acute respiratory distress syndrome (ARDS), but it lacks effective drugs for prevention and treatment of this pathophysiology. Our previous experiment confirmed that RUNX1 promoted alveolar hypercoagulation and fibrinolytic inhibition through NF-κB pathway. Other studies demonstrated that 6-gingerol regulated inflammation and metabolism by inhibiting the NF-κB signaling pathway. We assume that 6-gingerol would ameliorate alveolar hypercoagulation and fibrinolytic inhibition via RUNX1/ NF-κB pathway in LPS-induced ARDS. MethodsRat ARDS model was replicated through LPS inhalation. Before LPS inhalation, the rats were intraperitoneally treated with different doses of 6-gingerol or the same volume of normal saline (NS) for 12 h, and then intratracheal inhalation of LPS for 24 h. In cell experiment, alveolar epithelial cell type II (AECII) was treated with 6-gingerol for 6 h and then with LPS for another 24 h. RUNX1 gene was down-regulated both in pulmonary tissue and in cells. Tissue factor (TF), plasminogen Activator Inhibitor 1(PAI-1) and thrombin were determined by Wester-blot (WB), qPCR or by enzyme-linked immunosorbent (ELISA). Lung injury score, pulmonary edema and pulmonary collagen III in rat were assessed. NF-κB pathway were also observed in vivo and in vitro. The direct binding capability of 6-gingerol to RUNX1 was confirmed by using Drug Affinity Responsive Target Stability test (DARTS). Results6-gingerol dose-dependently attenuated LPS-induced lung injury and pulmonary edema. LPS administration caused excessive TF and PAI-1 expression both in pulmonary tissue and in AECII cell and a large amount of TF, PAI-1 and thrombin in bronchial alveolar lavage fluid (BALF), which all were effectively decreased by 6-gingerol treatment in a dose-dependent manner. The high collagen Ⅲ level in lung tissue provoked by LPS was significantly abated by 6-gingerol. 6-gingerol was seen to dramatically inhibit the LPS-stimulated activation of NF-κB pathway, indicated by decreases of p-p65/total p65, p-IKKβ/total IKKβ, and also to suppress the RUNX1 expression. RUNX1 gene knock down or RUNX1 inhibitor Ro5-3335 significantly enhanced the efficacies of 6-gingerol in vivo and in vitro, but RUNX1 over expression remarkably impaired the effects of 6-gingerol on TF, PAI-1 and on NF-κB pathway. DARTS result showed that 6-gingerol directly bond to RUNX1 molecules. ConclusionsOur experimental data demonstrated that 6-gingerol ameliorates alveolar hypercoagulation and fibrinolytic inhibition via RUNX1/NF-κB pathway in LPS-induced ARDS. 6-gingerol is expected to be an effective drug in ARDS.

A-249 Theranostic Algorithm: sensitivity and Specificity of a Composite Index Test for Guiding Treatment in Severe COVID-19

Abstract Background Since the outbreak of the pandemic, severely affected COVID-19 patients receive standard of care at intensive care unit (ICU), but clinical trials are still ongoing for new expensive treatments. There is a need for guiding therapeutic decisions to restrain the public healthcare costs and to target the most efficient therapy. Based on the pathophysiology of SARS-CoV-2 on its ACE2-receptor, the angiotensin pathway is activated and circulating biomarkers of interest can be measured. This diagnostic test accuracy study describes how to classify COVID-19 patients in severe vs mild cases with the intention of guiding treatment decisions, to prevent long term sequels like pulmonary fibrosis. A theranostic approach is proposed, which combines in vitro diagnostics and personalized therapeutics. Methods N = 17 severely affected COVID-19 with acute respiratory distress syndrome (ARDS) at ICU were included and compared to N = 7 mild or asymptomatic COVID-19 cases and to N = 10 healthy controls. Follow-up samples have been collected during pulmonology consultation at three time points during one year post-ICU (N = 39). Non-parametrical statistics were used; data are expressed as [median (IQR)] and P < 0.05 is considered to be statistically significant. The biological markers angiotensin-(1-7) (Ang-(1-7)), transforming growth factor beta (TGF-β), ferritin, C-reactive protein (CRP from Roche) and Krebs von den Lungen 6 (KL-6 from Fujirebio) were measured in plasma samples. Those biomarkers represent a disequilibrium in lung protection, fibrogenesis, inflammation and hyperplasia of alveolar epithelial cells type II. Cut-off for a composite index was obtained through receiver operating curve (ROC). Results COVID-19 patients show higher Ang-(1-7) concentrations than healthy controls (P < 0.05). Critical patients at ICU show Ang-(1-7) deficit [124 pg/mL (81–154)], compared to asymptomatic COVID-19 cases [147 pg/mL (138–201)] (P < 0.05). COVID-19 patients with insufficient Ang-(1-7) are eligible for substitution therapy and novel expensive therapies beside standard of care, while the subpopulation of high Ang-(1-7) is analyzed with a composite index test including TGF-β, ferritin and CRP. A composite index of <34 differentiates asymptomatic COVID-19 from severe COVID-19 at ICU having acute respiratory distress syndrome (sensitivity = 100%, specificity = 80%, AUC = 0.933, LR = 5). The patients without risk for pulmonary sequels are not eligible for expensive treatment.After 1 year, KL-6 (<275 U/mL) and TGF- β (<34 968 pg/mL) normalise in only 25%, respectively 33% of severe COVID-19 patients. Within the first year of FU post-ICU, the mean KL-6 value in the patient population does not significantly change at different measuring moments (P = 0.63), while TGF-β decreases gradually at 3, 6 and 12 months post-ICU (P < 0.0001). Conclusion This theranostic algorithm predicts whether a patient infected by SARS-CoV-2 is at risk of developing clinical complications and supports clinical decision making concerning therapy. A supported therapeutic choice, based on objective biomarker measurements, could diminish long-term sequelae like pulmonary fibrosis. Clinical trials using companion drugs (e.g. Ang-(1-7) substitution therapy, MAS-receptor agonist), anti-fibrotics, interferon therapy, or monoclonal antibodies, could also rely on those biomarkers. The measurement of Ang-(1-7) for example, could categorize patients in the targeted subpopulation before administrating Ang-(1-7) substitution therapy, aiming at obtaining better treatment efficacy.

Recombinant CXCL17 Treatment Alleviates Hyperoxia-Induced Lung Apoptosis and Inflammation In Vivo and Vitro by Activating the AKT Pathway: A Possible Therapeutic Approach for Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD), caused by hyperoxia exposure, is the most common complication affecting preterm infants. The C-X-C motif chemokine ligand 17 (CXCL17) belongs to the chemokine family that plays important roles in various processes, but the function in BPD is unknown. Elevated serum CXCL17 levels were observed in human premature infants with hyperoxia-induced lung injury, suggesting that CXCL17 might be involved in BPD. To further validate our speculation, studies were conducted in a hyperoxia-induced lung injury mouse model and primary murine alveolar epithelial cells Type II (T2AEC) cells exposed to hyperoxia. RT-qPCR and western blot were used to validate CXCL17 expression in newborn mice. Hyperoxia exposure-induced lung injury was determined by assessing the lung wet-weight/dry-weight ratio and histological changes. Oxidative stress and inflammatory factors were examined by ELISA assay and RT-qPCR. Reactive oxygen species (ROS) level was evaluated by DHE staining. Apoptosis was assessed by TUNEL staining and western blot. The results showed that hyperoxia exposure increased CXCL17 levels in newborn mice pups. Hyperoxia exposure increased lung wet-weight/dry-weight ratio, increased alveolar diameter and enlarged alveoli, and reduced surfactant protein C expression. However, recombinant CXCL17 (rCXCL17) treatment alleviated hyperoxia-induced lung injury. rCXCL17 treatment inhibited hyperoxia-induced inflammation, oxidative stress, and apoptosis in neonatal mice. These results were further verified in T2AEC cells. Additionally, rCXCL17 treatment activated the AKT pathway, which is a protective pathway in BPD. Collectively, rCXCL17 alleviates hyperoxia-induced lung injury in neonatal mice by activating the AKT pathway, indicating that CXCL17 may be a promising target for BPD therapy.

ISRIB inhibits the senescence of type II pulmonary epithelial cells to alleviate pulmonary fibrosis induced by silica in mice

The role and mechanisms of integrated stress response inhibitor (ISRIB) on silicosis are still not well defined. In the present study, the effects of ISRIB on cellular senescence and pulmonary fibrosis in silicosis were evaluated by RNA sequencing, micro-computed tomography, pulmonary function assessment, histological examination, and Western blot analysis. The results showed that ISRIB significantly reduced the degree of pulmonary fibrosis in mice with silicosis and reduced the expression of type I collagen, fibronectin, α-smooth muscle actin, and transforming growth factor-β1. Both in vivo and in vitro results showed that ISRIB reversed the expression of senescence-related factors β-galactosidase, phosphor-ataxia telangiectasia mutated, phosphor-ataxia telangiectasia and Rad3-related protein, p-p53, p21, p16, and plasminogen activator inhibitor type 1. The aforementioned results were consistent with the sequencing results. These findings implied that ISRIB might reduce the degree of pulmonary fibrosis in mice with silicosis by inhibiting the cellular senescence of alveolar epithelial cell type II.

AMPK activation improves recovery from pneumonia-induced lung injury via reduction of er-stress and apoptosis in alveolar epithelial cells

BackgroundBacterial pneumonia and related lung injury are among the most frequent causes of mortality in intensive care units, but also inflict serious and prolonged respiratory complications among survivors. Given that endoplasmic reticulum (ER) stress is a hallmark of sepsis-related alveolar epithelial cell (AEC) dysfunction, we tested if AMP-activated protein kinase (AMPK) affects recovery from ER stress and apoptosis of AECs during post-bacterial infection.MethodsIn a murine model of lung injury by P. aeruginosa non-lethal infection, therapeutic interventions included AMPK activator metformin or GSK-3β inhibitor Tideglusib for 96 h. Recovery from AEC injury was evidenced by accumulation of soluble T-1α (AEC Type 1 marker) in BAL fluids along with fluorescence analysis of ER-stress (CHOP) and apoptosis (TUNEL) in lung sections. AMPK phosphorylation status and mediators of ER stress were determined via Immunoblot analysis from lung homogenates. Macrophage-dependent clearance of apoptotic cells was determined using flow cytometry assay.ResultsP. aeruginosa-induced lung injury resulted in accumulation of neutrophils and cellular debris in the alveolar space along with persistent (96 h) ER-stress and apoptosis of AECs. While lung infection triggered AMPK inactivation (de-phosphorylation of Thr172-AMPK), metformin and Tideglusib promptly restored the AMPK activation status. In post infected mice, AMPK activation reduced indices of lung injury, ER stress and related apoptosis of AECs, as early as 24 h post administration of AMPK activators. In addition, we demonstrate that the extent of apoptotic cell accumulation is also dependent on AMPK-mediated clearance of apoptotic cells by macrophages.ConclusionsOur study provides important insights into AMPK function in the preservation of AEC viability after bacterial infection, in particular due reduction of ER-stress and apoptosis, thereby promoting effective recovery from lung injury after pneumonia.

Kaempferol inhibits SARS-CoV-2 invasion by impairing heptad repeats-mediated viral fusion

BackgroundThe continuous evolution of SARS-CoV-2 has underscored the development of broad-spectrum prophylaxis. Antivirals targeting the membrane fusion process represent promising paradigms. Kaempferol (Kae), an ubiquitous plant flavonol, has been shown efficacy against various enveloped viruses. However, its potential in anti-SARS-CoV-2 invasion remains obscure. PurposeTo evaluate capabilities and mechanisms of Kae in preventing SARS-CoV-2 invasion. MethodsTo avoid interference of viral replication, virus-like particles (VLPs) constructed with luciferase reporter were applied. To investigate the antiviral potency of Kae, human induced pluripotent stem cells (hiPSC)-derived alveolar epithelial cells type II (AECII) and human ACE2 (hACE2) transgenic mice were utilized as in vitro and in vivo models, respectively. Using dual split protein (DSP) assays, inhibitory activities of Kae in viral fusion were determined in Alpha, Delta and Omicron variants of SARS-CoV-2, as well as in SARS-CoV and MERS-CoV. To further reveal molecular determinants of Kae in restricting viral fusion, synthetic peptides corresponding to the conserved heptad repeat (HR) 1 and 2, involved in viral fusion, and the mutant form of HR2 were explored by circular dichroism and native polyacrylamide gel electrophoresis. ResultsKae inhibited SARS-CoV-2 invasion both in vitro and in vivo, which was mainly attributed to its suppressive effects on viral fusion, but not endocytosis, two pathways that mediate viral invasion. In accordance with the proposed model of anti-fusion prophylaxis, Kae functioned as a pan-inhibitor of viral fusion, including three emerged highly pathogenic coronaviruses, and the currently circulating Omicron BQ.1.1 and XBB.1 variants of SARS-CoV-2. Consistent with the typical target of viral fusion inhibitors, Kae interacted with HR regions of SARS-CoV-2 S2 subunits. Distinct from previous inhibitory fusion peptides which prevent the formation of six-helix bundle (6-HB) by competitively interacting with HRs, Kae deformed HR1 and directly reacted with lysine residues within HR2 region, the latter of which was considered critical for the preservation of stabilized S2 during SARS-CoV-2 invasion. ConclusionsKae prevents SARS-CoV-2 infection by blocking membrane fusion and possesses a broad-spectrum anti-fusion ability. These findings provide valuable insights into potential benefits of Kae-containing botanical products as a complementary prophylaxis, especially during the waves of breakthrough infections and re-infections.

MiR-9 targeting RUNX1 improves LPS-induced alveolar hypercoagulation and fibrinolysis inhibition through NF-κB inactivation in ARDS

BackgroundAcute respiratory distress syndrome (ARDS) is a clinical and pathophysiological complex syndrome with high mortality. Alveolar hypercoagulation and fibrinolytic inhibition constitute the core part of the pathophysiology of ARDS. miR-9 (microRNA-9a-5p) plays an important role in the pathogenesis of ARDS, but whether it regulates alveolar pro-coagulation and fibrinolysis inhibition in ARDS remains to be elucidated. We aimed to determine the contributing role of miR-9 on alveolar hypercoagulation and fibrinolysis inhibition in ARDS. MethodsIn the ARDS animal model, we first observed the miR-9 and runt-related transcription factor 1 (RUNX1) expression in lung tissue, the effects of miR-9 on alveolar hypercoagulation and fibrinolytic inhibition in ARDS rats, and the efficacy of miR-9 on acute lung injury. In the cell, alveolar epithelial cells type II (AECII) were treated with LPS, and the levels of miR-9 and RUNX1 were detected. Then we observed the effects of miR-9 on procoagulant and fibrinolysis inhibitor factors in cells. Finally, we explored whether the efficacies of miR-9 were associated with RUNX1; we also preliminarily examined the miR-9 and RUNX1 levels in plasma in patients with ARDS. ResultsIn ARDS rats, miR-9 expression decreased, but RUNX1 expression increased in the pulmonary tissue of ARDS rats. miR-9 displayed to attenuate lung injury and pulmonary wet/dry ratio. Study results in vivo demonstrated that miR-9 ameliorated alveolar hypercoagulation and fibrinolysis inhibition and attenuated the collagen III expressions in tissue. miR-9 also inhibited NF-κB signaling pathway activation in ARDS. In LPS-induced AECII, the expression changes of both miR-9 and RUNX1 were similar to those in pulmonary tissue in the animal ARDS model. miR-9 effectively inhabited tissue factor (TF), plasma activator inhibitor (PAI-1) expressions, and NF-κB activation in LPS-treated ACEII cells. Besides, miR-9 directly targeted RUNX1, inhibiting TF and PAI-1 expression and attenuating NF-κB activation in LPS-treated AECII cells. Clinically, we preliminarily found that the expression of miR-9 was significantly reduced in ARDS patients compared to non-ARDS patients. ConclusionOur experimental data indicate that by directly targeting RUNX1, miR-9 improves alveolar hypercoagulation and fibrinolysis inhibition via suppressing NF-κB pathway activation in LPS-induced rat ARDS, implying that miR-9/RUNX1 is expected to be a new therapeutic target for ARDS treatment.

Identification of a subset of lung neutrophils that promote Acute Lung Injury resolution in mice

Abstract The acute respiratory distress syndrome (ARDS) is a major cause of respiratory failure with limited therapeutic options. Unresolving inflammation in the lungs and alveolar-capillary barrier dysfunction are main features of ARDS. The sharp increase in the incidence of ARDS during COVID19 emphasized the need for a better understanding of immunological events in ARDS that inform novel therapeutics. Here, we used a model of self-limited acid-induced ALI by selectively instilling HCL to the left lung of adult mice. The time-course of barrier dysfunction was determined via quantification of lung consolidation by micro-computed tomography, while inflammation was assessed by histology and flow cytometry. Neutrophils, rapidly recruited into the lungs, decreased over time during resolution while macrophage numbers, reduced during initial stages, increased. Immunophenotyping of the leukocyte recruitment to the lungs during the resolution of injury uncovered a neutrophils’ subset that was expressing SiglecF. These cells were distinct from eosinophils and phenotypically, and functionally different from the classical SiglecF-negative neutrophils. The roles for SiglecF+ neutrophils were further assessed by in vitro functional studies, adoptive transfer experiments, and lipidomic analysis. Depletion of neutrophils impaired alveolar epithelial cell type II (AT2) repair, while the adoptive transfer of SiglecF+ neutrophils accelerated epithelial cell restitution. Among the mechanisms associated with the SiglecF+ neutrophils in lung repair was the production of specialized pro-resolving mediators and CSF1. In sum, we identified protective roles for a subset of tissue neutrophils during the resolution of lung injury in mice.

Abstract 2106: Importance of alveolar epithelial cell type 2 populations in non-small cell lung cancer progression from localized to metastatic disease

Abstract Introduction: Non-small cell lung cancer (NSCLC) is by far the leading cancer killer. Identifying personalized treatment strategies to prevent and treat metastases remains an unmet clinical need. Alveolar epithelial type II (AT2) cells are self-renewing epithelial stem cells that have been identified to initiate a majority NSCLCs. Previously, we have reported the presence of multiple AT2 cell types in micrometastatic circulating tumor cell-derived xenograft (CDX) models and patient metastatic tumors. These findings provide a rationale to further study whether and how AT2 cells contribute to metastatic progression. Hypothesis: We hypothesize that AT2 cell types have a functional role in metastasis tumorigenicity of NSCLC. Methods: A library of NSCLC patient-derived circulating tumor cell (CTC) lines, xenograft (PDX) models, and publicly available data sets of patients’ NSCLC tumor tissues were subjected to single cell/bulk RNA sequencing and analysis to determine the frequencies and expression patterns of AT2 subclones. Using magnetic bead sorting AT2 cells were enriched and AT2-associated tumorigenicity, migratory and invasion capacity determined using 3D culture and PDX models. The effects of AT2 depletion on PDX tumor characteristics were evaluated histologically. Frequencies of AT2 phenotypes in primary and metastatic tumors were validated in human tissue microarrays and patient CTCs. Results: An additional AT2 population was identified in NSCLC brain metastases and primary lung tumors that had metastasized already. However, this additional AT2 cell population was absent in primary lung tumors of patients that had not metastasized and in patients with lymph node, pleural and liver metastases. AT2-depleted NSCLC cell lines had reduced tumorigenicity in PDX models in comparison to tumors derived from whole cell populations. In addition, tumors derived from AT2 depleted cell lines were highly necrotic. AT2-depleted cell lines showed decreased migratory and invasion capacity in 3D models. Further, AT2 phenotypes were identified at high rates in NSCLC patients’ metastases and CTCs. Conclusion: Findings indicate an important role of AT2 cells in metastatic progression, beyond their known role in NSCLC initiation. The role of AT2 in metastasis migration, invasion and growth offers unique opportunities to identify novel therapeutic targets. Expansion of translational findings on AT2 cells has high potential for clinical impact to prevent or treat metastatic disease in NSCLC patients. Citation Format: Kanve Nagaraj Suvilesh. Importance of alveolar epithelial cell type 2 populations in non-small cell lung cancer progression from localized to metastatic disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2106.

Electrotaxis of alveolar epithelial cells in direct-current electric fields

PurposeThis study aims to elucidate the electrotaxis response of alveolar epithelial cells (AECs) in direct-current electric fields (EFs), explore the impact of EFs on the cell fate of AECs, and lay the foundation for future exploitation of EFs for the treatment of acute lung injury. MethodsAECs were extracted from rat lung tissues using magnetic-activated cell sorting. To elucidate the electrotaxis responses of AECs, different voltages of EFs (0, 50, 100, and 200 mV/mm) were applied to two types of AECs, respectively. Cell migrations were recorded and trajectories were pooled to better demonstrate cellular activities through graphs. Cell directionality was calculated as the cosine value of the angle formed by the EF vector and cell migration. To further demonstrate the impact of EFs on the pulmonary tissue, the human bronchial epithelial cells transformed with Ad12-SV40 2B (BEAS-2B cells) were obtained and experimented under the same conditions as AECs. To determine the influence on cell fate, cells underwent electric stimulation were collected to perform Western blot analysis. ResultsThe successful separation and culturing of AECs were confirmed through immunofluorescence staining. Compared with the control, AECs in EFs demonstrated a significant directionality in a voltage-dependent way. In general, type Ⅰ alveolar epithelial cells migrated faster than type Ⅱ alveolar epithelial cells, and under EFs, these two types of cells exhibited different response threshold. For type Ⅱ alveolar epithelial cells, only EFs at 200 mV/mm resulted a significant difference to the velocity, whereas for, EFs at both 100 mV/mm and 200 mV/mm gave rise to a significant difference. Western blotting suggested that EFs led to an increased expression of a AKT and myeloid leukemia 1 and a decreased expression of Bcl-2-associated X protein and Bcl-2-like protein 11. ConclusionEFs could guide and accelerate the directional migration of AECs and exert antiapoptotic effects, which indicated that EFs are important biophysical signals in the re-epithelialization of alveolar epithelium in lung injury.

Xenobiotic-sensing nuclear receptors as targets for phthalates-induced lung injury and antagonism of lycopene

Phthalates are extensively used in the production of plastics products and have been verified to induce lung injury. Lycopene (LYC) has proved an effective preventive and can be utilized to prevent phthalates-induced toxicity. However, the role of phthalate in pathogenesis of lung injury remain poorly researched, and little work has been devoted whether LYC could alleviate phthalate-induced lung toxicity via modulating nuclear xenobiotic receptors (NXRs) response. Here, di (2-ethylhexyl) phthalate (DEHP) is used as the representative of phthalates for further studies on toxicity of phthalates and the antagonistic role of LYC in phthalates-induced lung injury. We found that DEHP exposure caused alveoli destruction and alveolar epithelial cells type II damage. Mechanistically, DEHP exposure increased nuclear accumulation of aryl hydrocarbon receptor (AHR) and its downstream genes level, including cytochrome P450-dependent monooxygenase (CYP) 1A1 and CYP1B1. Constitutive androstane receptor (CAR) and their downstream gene level, including CYP2E1 are also increased after phthalates exposure. Significantly, LYC supplementation relieves lung injury from DEHP exposure by inhibiting the activation of NXRs. We confirm that NXRs plays a key role in phthalates-induced lung injury. Our study showed that LYC may have a positive role in alleviating the toxicity effects of phthalates, which provides an effective strategy for revising phthalates-induced injury.

Andrographolide Suppresses Expressions of Coagulation and Fibrinolytic Inhibition-Related Factors in LPS-Induced Alveolar Epithelial Cell Type II via NF-κB Signal Pathway In Vitro

BackgroundAndrographolide (Andro) has been confirmed to ameliorate alveolar hypercoagulation and fibrinolysis inhibition via NF-κB pathway in acute respiratory distress syndrome (ARDS), but the specific target of Andro is unknown.PurposeOur aim is to explore the specific target of Andro through which the drug exerted its effects on alveolar hypercoagulation and fibrinolytic inhibition in LPS-induced ARDS.MethodsAECII was treated with different doses of Andro for 1 h, and then stimulated with LPS for 24 h. Expressions of tissue factor (TF), plasminogen activator inhibitor (PAI)-1 and tissue factor pathway inhibitor (TFPI) were detected. Concentrations of thrombin-antithrombin complex (TAT), pro-collagen type III peptide (PIIIP), antithrombin III (ATIII) and activated protein C (APC) in cell supernatant were measured by enzyme linked immunosorbent assay (ELISA). NF-κB signaling pathways activation was simultaneously determined. AECII with p65 down-/over-expression were used as control.ResultsAndro effectively inhibited TF and PAI-1 and promoted TFPI expressions on AECII induced by LPS stimulation. Andro also significantly suppressed the productions of TAT and PIIIP but promoted ATIII and APC secretions from the LPS-treated cell. Furthermore, Andro application obviously inhibited NF-κB signaling pathway activation provoked by LPS, as shown by decreased level of phosphorylation (p‑)-IKKβ/IKKβ, p-p65/p65 and p65 DNA binding activity. The effects of Andro on those factors were obviously strengthened by down- but were weakened by up-regulation of p65 gene in AECII cell.ConclusionsOur data demonstrates that targeting AECII is the mechanism by which Andro ameliorates alveolar hypercoagulaiton and fibrinolytic inhibition via NF-κB pathway in ARDS. Andro is worth to be clinically further studied in ARDS treatment.

Distinct Epithelial Cell Profiles in Normal Versus Induced-Congenital Diaphragmatic Hernia Fetal Lungs.

BackgroundRecent studies identified a great diversity of cell types in precise number and position to create the architectural features of the lung that ventilation and respiration at birth depend on. With damaged respiratory function at birth, congenital diaphragmatic hernia (CDH) is one of the more severe causes of fetal lung hypoplasia with unspecified cellular dynamics.Objectives To characterize the epithelial cell tissue in hypoplastic lungs, a careful analysis regarding pulmonary morphology and epithelial cell profile was conducted from pseudoglandular-to-saccular phases in normal versus nitrofen-induced CDH rat lungs.DesignOur analysis comprises three experimental groups, control, nitrofen (NF) and CDH, in which the relative expression levels (western blot) by group and developmental stage were analyzed in whole lung. Spatiotemporal distribution (immunohistochemistry) was revealed by pulmonary structure during normal and hypoplastic fetal lung development. Surfactant protein-C (SP-C), calcitonin gene-related peptide (CGRP), clara cell secretory protein (CCSP), and forkhead box J1 (FOXJ1) were the used molecular markers for alveolar epithelial cell type 2 (AEC2), pulmonary neuroendocrine, clara, and ciliated cell profiles, respectively.ResultsGenerally, we identified an aberrant expression of SP-C, CGRP, CCSP, and FOXJ1 in nitrofen-exposed lungs. For instance, the overexpression of FOXJ1 and CGRP in primordia of bronchiole defined the pseudoglandular stage in CDH lungs, whereas the increased expression of CGRP in bronchi; FOXJ1 and CGRP in terminal bronchiole; and SP-C in BADJ classified the canalicular and saccular stages in hypoplastic lungs. We also described higher expression levels in NF than CDH or control groups for both FOXJ1 in bronchi, terminal bronchiole and BADJ at canalicular stage, and SP-C in bronchi and terminal bronchiole at canalicular and saccular stages. Finally, we report an unexpected expression of FOXJ1 in BADJ at canalicular and saccular stages, whereas the multi cilia observed in bronchi were notably absent at embryonic day 21.5 in induced-CDH lungs.ConclusionThe recognized alterations in the epithelial cell profile contribute to a better understanding of neonatal respiratory insufficiency in induced-CDH lungs and indicate a problem in the epithelial cell differentiation in hypoplastic lungs.

Increased Serum SP-D Level, Neutrophils and Lymphocytes Sputum in Malang Splendid Bird Market Workers

Background: Workers in the bird market have a high risk of exposure in the form of air pollution, pollutant particles including debris / organic dust, loose feathers, insects/ticks, aerosol particles in food, bird excreta (ammonia), various kinds of gram bacteria, fungi and virus. Exposure to particles will stimulate the immune system against harmful pathogens in the form of inflammatory response. An infection or injury will stimulate the secretion of Surfactant protein-D (SP-D) which is a group of collectin (collagen-lectin) with subgroups of the C-type lectin superfamily, together with bovine coglutinin, mannose-binding lectin (MBL), and CL43 protein. This aim of this study was to determine serum SP-D and neutrophil and sputum lymphocyte levels in workers at splendid bird market.Methods: A cross sectional analytic observational study on 35 subjects, analyzed the characteristics of the workers, calculated neutrophil types, lymphocytes on induced sputum and serum SP-D levels using sandwich ELISA.Results: Mean SP-D serum levels in workers in the bird market environment increased (mean SD: 81.39 + 47.656 ng/ml) from normal levels (60 ± 3 ng/ml). There was a significant positive correlation between length of exposure and serum SP-D levels (r: 0.693; p <0.001). There was an average increase in the percentage of neutrophils and sputum lymphocytes (90.71% + 4.04% and 9.17% + 4.42%) compared to normal limit (50.3% + 23.5% and 2.6% + 5.2%).Conclusion: Inhalation exposure in the Bird Market environment can cause an increase in the percentage of neutrophils, sputum lymphocytes and serum SP-D levels in workers that indicate an airway inflammation process, as well as an alleged increase in alveolar wall permeability, damage and regeneration of alveolar epithelial cell type II cells (AEC type II).

GM-CSF: Orchestrating the Pulmonary Response to Infection.

This review summarizes the structure and function of the alveolar unit, comprised of alveolar macrophage and epithelial cell types that work in tandem to respond to infection. Granulocyte-macrophage colony-stimulating factor (GM-CSF) helps to maintain the alveolar epithelium and pulmonary immune system under physiological conditions and plays a critical role in restoring homeostasis under pathologic conditions, including infection. Given the emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and global spread of coronavirus disease 2019 (COVID-19), with subsequent acute respiratory distress syndrome, understanding basic lung physiology in infectious diseases is especially warranted. This review summarizes clinical and preclinical data for GM-CSF in respiratory infections, and the rationale for sargramostim (yeast-derived recombinant human [rhu] GM-CSF) as adjunctive treatment for COVID-19 and other pulmonary infectious diseases.

Dynamic Regulation of GH-IGF1 Signaling in Injury and Recovery in Hyperoxia-Induced Neonatal Lung Injury.

Prematurely born infants often require supplemental oxygen that impairs lung growth and results in arrest of alveolarization and bronchopulmonary dysplasia (BPD). The growth hormone (GH)- and insulin-like growth factor (IGF)1 systems regulate cell homeostasis and organ development. Since IGF1 is decreased in preterm infants, we investigated the GH- and IGF1 signaling (1) in newborn mice with acute and prolonged exposure to hyperoxia as well as after recovery in room air; and (2) in cultured murine lung epithelial cells (MLE-12) and primary neonatal lung fibroblasts (pLFs) after treatment with GH, IGF1, and IGF1-receptor (IGF1-R) inhibitor or silencing of GH-receptor (Ghr) and Igf1r using the siRNA technique. We found that (1) early postnatal hyperoxia caused an arrest of alveolarization that persisted until adulthood. Both short-term and prolonged hyperoxia reduced GH-receptor expression and STAT5 signaling, whereas Igf1 mRNA and pAKT signaling were increased. These findings were related to a loss of epithelial cell markers (SFTPC, AQP5) and proliferation of myofibroblasts (αSMA+ cells). After recovery, GH-R-expression and STAT5 signaling were activated, Igf1r mRNA reduced, and SFTPC protein significantly increased. Cell culture studies showed that IGF1 induced expression of mesenchymal (e.g., Col1a1, Col4a4) and alveolar epithelial cell type I (Hopx, Igfbp2) markers, whereas inhibition of IGF1 increased SFTPC and reduced AQP5 in MLE-12. GH increased Il6 mRNA and reduced proliferation of pLFs, whereas IGF1 exhibited the opposite effect. In summary, our data demonstrate an opposite regulation of GH- and IGF1- signaling during short-term/prolonged hyperoxia-induced lung injury and recovery, affecting alveolar epithelial cell differentiation, inflammatory activation of fibroblasts, and a possible uncoupling of the GH-IGF1 axis in lungs after hyperoxia.

Alveolar macrophages and epithelial cells: The art of living together.

In this issue of JEM, Gschwend et al. (2021. J. Exp. Med.https://doi.org/10.1084/jem.20210745) reveal the indispensable role of alveolar epithelial cells type 2 in controlling the density of alveolar macrophages. This study highlights the intricate crosstalk that lung stroma and macrophages undergo to maintain homeostasis.