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Protein Expression and Purification Jun 2024We previously identified surfactant protein D (SP-D) in the bottlenose dolphin Tursiops truncatus as a unique evolutionary factor of the cetacean pulmonary immune...
We previously identified surfactant protein D (SP-D) in the bottlenose dolphin Tursiops truncatus as a unique evolutionary factor of the cetacean pulmonary immune system. In this short report, recombinant SP-D of bottlenose dolphin (dSP-D) was synthesized in mammalian cells, and its properties were analyzed in vitro. The recombinant proteins were purified using Ni-carrier or Co-carrier. Sodium dodecyl sulfate poly-acrylamide gel electrophoresis and western blotting revealed a 50 kDa major band with minor secondary bands. Enzyme-linked immunosorbent assay-like methods revealed that recombinant dSP-D bonded to gram-positive and gram-negative bacterial walls. Our findings suggest the clinical usefulness of dSP-D for cetacean pneumonia.
PubMed: 38880192
DOI: 10.1016/j.pep.2024.106523 -
American Journal of Respiratory Cell... Jun 2024Lamellar body (LB) is a tissue-specific lysosome-related organelle in type II alveolar cells, which is the main site for the synthesis, storage and secretion of...
Lamellar body (LB) is a tissue-specific lysosome-related organelle in type II alveolar cells, which is the main site for the synthesis, storage and secretion of pulmonary surfactants. Defects in pulmonary surfactants lead to a variety of respiratory and immune-related disorders. LB biogenesis is closely related to its function, but the underlying regulatory mechanism is largely unclear. Here, we found that deficiency of HPS6, a subunit of BLOC-2 (biogenesis of lysosome-related organelles complex-2), led to the reduction of the steady-state level of V-ATPase and the increase of luminal pH of LB. Furthermore, we observed increased LB size, accumulated surfactant proteins, and altered lipid profiling of lung tissue and bronchoalveolar lavage fluid due to HPS6 deficiency. These findings suggest that HPS6 regulates the distribution of V-ATPase on LBs to maintain its luminal acidity and LB homeostasis. This may provide new insights into the LB pathology.
PubMed: 38864759
DOI: 10.1165/rcmb.2022-0492OC -
American Journal of Physiology. Lung... Jun 2024COVID-19 syndrome is characterized by acute lung injury, hypoxemic respiratory failure, and high mortality. Alveolar Type 2 (AT2) cells are essential for gas exchange,...
COVID-19 syndrome is characterized by acute lung injury, hypoxemic respiratory failure, and high mortality. Alveolar Type 2 (AT2) cells are essential for gas exchange, repair, and regeneration of distal lung epithelium. We have shown that the causative agent, SARS-CoV-2 and other β-coronavirus genus members induce an ER stress response , however the consequences for host AT2 function are less understood. To study this, two murine models of coronavirus infection were employed- mouse hepatitis virus-1 (MHV-1) in A/J mice and a mouse adapted SARS-CoV-2 strain. MHV-1 infected mice exhibited dose-dependent weight loss with histological evidence of distal lung injury accompanied by elevated bronchoalveolar lavage fluid (BALF) cell counts and total protein. AT2 cells showed evidence of both viral infection and increased BIP/GRP78 expression, consistent with activation of the unfolded protein response (UPR). The AT2 UPR included increased IRE1α signaling and a biphasic response in PERK signaling accompanied marked reductions in AT2 and BALF surfactant protein (SP-B, SP-C) content, increases in surfactant surface tension, and emergence of a re-programmed epithelial cell population (, ). The loss of a homeostatic AT2 endophenotype was attenuated by treatment with the IRE1α inhibitor OPK711. As proof-of-concept, C57BL6 mice infected with mouse-adapted SARS-CoV-2 demonstrated similar lung injury and evidence of disrupted surfactant homeostasis. We conclude that lung injury from β-coronavirus infection results from an aberrant host response activating multiple AT2 UPR pathways, altering surfactant metabolism/function, and changing AT2 endophenotypes offering a mechanistic link between SARS-CoV-2 infection, AT2 cell biology, and acute respiratory failure.
PubMed: 38860845
DOI: 10.1152/ajplung.00324.2023 -
Immunity, Inflammation and Disease Jun 2024Severe cases of COVID-19 often lead to the development of acute respiratory syndrome, a critical condition believed to be caused by the harmful effects of SARS-CoV-2 on... (Review)
Review
BACKGROUND
Severe cases of COVID-19 often lead to the development of acute respiratory syndrome, a critical condition believed to be caused by the harmful effects of SARS-CoV-2 on type II alveolar cells. These cells play a crucial role in producing pulmonary surfactants, which are essential for proper lung function. Specifically focusing on surfactant proteins, including Surfactant protein A (SP-A), Surfactant protein B, Surfactant protein C, and Surfactant protein D (SP-D), changes in the levels of pulmonary surfactants may be a significant factor in the pathological changes seen in COVID-19 infection.
OBJECTIVE
This study aims to gain insights into surfactants, particularly their impacts and changes during COVID-19 infection, through a comprehensive review of current literature. The study focuses on the function of surfactants as prognostic markers, diagnostic factors, and essential components in the management and treatment of COVID-19.
FINDING
In general, pulmonary surfactants serve to reduce the surface tension at the gas-liquid interface, thereby significantly contributing to the regulation of respiratory mechanics. Additionally, these surfactants play a crucial role in the innate immune system within the pulmonary microenvironment. Within the spectrum of COVID-19 infections, a compelling association is observed, characterized by elevated levels of SP-D and SP-A across a range of manifestations from mild to severe pneumonia. The sudden decline in respiratory function observed in COVID-19 patients may be attributed to the decreased synthesis of surfactants by type II alveolar cells.
CONCLUSION
Collectin proteins such as SP-A and SP-D show promise as biomarkers, offering potential avenues for predicting and monitoring pulmonary alveolar injury in the context of COVID-19. This clarification enhances our understanding of the molecular complexities contributing to respiratory complications in severe COVID-19 cases, providing a foundation for targeted therapeutic approaches using surfactants and refined clinical management strategies.
Topics: COVID-19; Humans; SARS-CoV-2; Pulmonary Surfactant-Associated Proteins; Pulmonary Surfactants; Biomarkers; Pulmonary Surfactant-Associated Protein D; Prognosis; Lung
PubMed: 38860749
DOI: 10.1002/iid3.1302 -
PloS One 2024Clear amniotic fluid aspiration syndrome (CAF-AS) is a very rare event occurring in 0.25% of our term clear amniotic fluids deliveries. The study's aims were: 1. to... (Observational Study)
Observational Study
BACKGROUND
Clear amniotic fluid aspiration syndrome (CAF-AS) is a very rare event occurring in 0.25% of our term clear amniotic fluids deliveries. The study's aims were: 1. to characterize the risk factors and outcomes associated with Clear Amniotic Fluid Aspiration Syndrome and 2. to compare the outcomes of Clear Amniotic Fluid Aspiration to Meconium Aspiration.
METHODS
This was an observational study over a 22-year period in a single level-3 medical center. Compared were parturient/labor characteristics and neonatal outcomes in cases with suspected Clear Amniotic Fluid Aspiration to cases suspected for Meconium Aspiration.
RESULTS
Out of 79,620 term deliveries there were 66,705 (83.8%) clear amniotic fluids and 12,915 (16.2%) meconium stained amniotic fluid (MSAF). Of neonates born with clear amniotic fluid, 166 (0.25%) were diagnosed with Clear Amniotic Fluid Aspiration Syndrome (CAF-AS), while 202 (15.7%) of those born with MSAF, were diagnosed with aspiration syndrome (MSAF-AS). Both conditions had comparable rates of mild manifestation (67.5% vs 69.2%, p = 0.63). Persistent pulmonary hypertension (PPH) occurred 5 times less in CAF-AS than MSAF-AS (4% vs 20%, OR 0.17, P< 0.0001) Both conditions presented similar rates of surfactant without PPH (11.1% vs 13.4%, p = 0.87). There was 1 postnatal death in CAF-AS vs 10 in MSAF.
CONCLUSION
CAF-AS were quantitatively quite similar in terms of need of actual active intervention of the neonatologists in the delivery room (166 vs 202, i.e. in terms of numbers of cases and not prevalence) to MSAF-AS.We identified in these cases two major specific causes: hyperkinetic explosive deliveries in multiparas and long-lasting episodes of maternal hypotension due to epidural/spinal anaesthesia during labor. Out of 140 million births per year in the world, it should be of concern that 3 million cases are neglected nowadays. Future studies should evaluate if this CAF-AS should benefit from a more active intervention such as immediate endotracheal suction at birth, this clear fluid being very easy to suction.
Topics: Humans; Female; Amniotic Fluid; Pregnancy; Meconium Aspiration Syndrome; Infant, Newborn; Adult; Risk Factors; Male
PubMed: 38857215
DOI: 10.1371/journal.pone.0301595 -
JCI Insight Jun 2024Progressive pulmonary fibrosis (PPF), defined as the worsening of various interstitial lung diseases (ILDs), currently lacks useful biomarkers. To identify novel...
Progressive pulmonary fibrosis (PPF), defined as the worsening of various interstitial lung diseases (ILDs), currently lacks useful biomarkers. To identify novel biomarkers for early detection of patients at risk of PPF, we performed a proteomic analysis of serum extracellular vesicles (EVs). Notably, the identified candidate biomarkers were enriched for lung-derived proteins participating in fibrosis-related pathways. Among them, pulmonary surfactant-associated protein B (SFTPB) in serum EVs could predict ILD progression better than the known biomarkers, serum KL-6 and SP-D, and it was identified as an independent prognostic factor from ILD-gender-age-physiology index. Subsequently, the utility of SFTPB for predicting ILD progression was evaluated further in 2 cohorts using serum EVs and serum, respectively, suggesting that SFTPB in serum EVs but not in serum was helpful. Among SFTPB forms, pro-SFTPB levels were increased in both serum EVs and lungs of patients with PPF compared with those of the control. Consistently, in a mouse model, the levels of pro-SFTPB, primarily originating from alveolar epithelial type 2 cells, were increased similarly in serum EVs and lungs, reflecting pro-fibrotic changes in the lungs, as supported by single-cell RNA sequencing. SFTPB, especially its pro-form, in serum EVs could serve as a biomarker for predicting ILD progression.
Topics: Extracellular Vesicles; Humans; Animals; Biomarkers; Mice; Male; Female; Pulmonary Fibrosis; Disease Progression; Pulmonary Surfactant-Associated Protein B; Middle Aged; Aged; Lung Diseases, Interstitial; Lung; Proteomics; Disease Models, Animal; Prognosis; Protein Precursors; Pulmonary Surfactant-Associated Proteins
PubMed: 38855869
DOI: 10.1172/jci.insight.177937 -
Translational Pediatrics May 2024Bronchopulmonary dysplasia (BPD), characterized by impaired lung development, remains a leading cause of morbidity and mortality in premature infants. The synthesis and...
BACKGROUND
Bronchopulmonary dysplasia (BPD), characterized by impaired lung development, remains a leading cause of morbidity and mortality in premature infants. The synthesis and metabolism of lipids play a critical role in normal lung development, such as dipalmitoylphosphatidylcholine, a key component of pulmonary surfactant (PS). Therefore, we conducted a lipidomics study of rat lung tissue to explore the changes of pulmonary lipid composition in the progression of BPD disease.
METHODS
In this study, we exposed neonatal Sprague-Dawley (SD) rats to hyperoxia for 14 days. After hyperoxia exposure, the lung tissues of rats were analyzed pathologically, and untargeted lipidomics was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
RESULTS
Hematoxylin-eosin (H&E) staining showed that the alveoli enlarged, the number of alveoli decreased and the pulmonary surfactant-associated protein D (SFTPD) decreased in hyperoxia-exposed rats. A total of 620 pulmonary lipids were detected by LC-MS/MS, covering 27 lipid categories. The most common lipids were triacylglycerol (TAG), followed by phosphatidylcholine (PC) and phosphatidylethanolamine (PE).
CONCLUSIONS
Compared with those rats exposed to normoxic conditions, the lipid levels in the lungs of rats exposed to hyperoxia for 14 days generally decreased, with the levels of TAG and PC decreasing most significantly. In short, our results provide a clue for finding therapeutic targets and biomarkers of a BPD rat model lung liposome.
PubMed: 38840687
DOI: 10.21037/tp-23-546 -
Thoracic Cancer Jun 2024The efficacy of anti-CTLA-4 antibody (ipilimumab) plus anti-programmed cell death 1 antibody (nivolumab) in treating advanced non-small cell lung cancer (NSCLC) is...
BACKGROUND
The efficacy of anti-CTLA-4 antibody (ipilimumab) plus anti-programmed cell death 1 antibody (nivolumab) in treating advanced non-small cell lung cancer (NSCLC) is impeded by an elevated risk of severe immune-related adverse events. However, our understanding of associations among pre-existing fibrosis, emphysematous changes, and objective indicators as predictive factors is limited for severe pneumonitis in NSCLC patients receiving this combination therapy. Thus, we retrospectively investigated these associations, including overall tumor burden, before treatment initiation in the Japanese population.
METHODS
We focused on patients (n = 76) with pre-existing interstitial lung disease (ILD) to identify predictors of severe pneumonitis. Variables included age, sex, smoking status, programmed cell death ligand 1 expression, overall tumor burden, chest computed tomography-confirmed fibrosis, serum markers, and respiratory function test results.
RESULTS
Severe pneumonitis was more frequent in patients with squamous cell carcinoma, fibrosis, low diffusing capacity for carbon monoxide (%DLCO), and high surfactant protein D (SP-D) level. Notably, squamous cell carcinoma, baseline %DLCO, and SP-D level were significant risk factors. Our findings revealed the nonsignificance of tumor burden (≥85 mm) in predicting severe pneumonitis, emphasizing the importance of pre-existing ILD. Conversely, in cases without pre-existing fibrosis, severe pneumonitis was not associated with %DLCO or SP-D level (93.2% vs. 91.9%, and 63.3 vs. 40.9 ng/mL, respectively) and was more common in patients with a large overall tumor burden (97.5 vs. 70.0 mm).
CONCLUSION
Vigilant monitoring and early intervention are crucial for patients with squamous cell carcinoma, high SP-D level, or low %DLCO undergoing ipilimumab plus nivolumab therapy.
PubMed: 38828610
DOI: 10.1111/1759-7714.15385 -
Acta Veterinaria Scandinavica May 2024A syndrome of acute non-cardiogenic pulmonary edema associated with hunting is prevalent in the drever breed, but etiology of this syndrome is currently unknown....
BACKGROUND
A syndrome of acute non-cardiogenic pulmonary edema associated with hunting is prevalent in the drever breed, but etiology of this syndrome is currently unknown. Alveolar surfactant has a critical role in preventing alveolar collapse and edema formation. The aim of this study was to investigate, whether the predisposition to hunting associated pulmonary edema in drever dogs is associated with impaired biophysical properties of alveolar surfactant. Seven privately owned drever dogs with recurrent hunting associated pulmonary edema and seven healthy control dogs of other breeds were included in the study. All affected dogs underwent thorough clinical examinations including echocardiography, laryngeal evaluation, bronchoscopy, and bronchoalveolar lavage (BAL) as well as head, neck and thoracic computed tomography imaging to rule out other cardiorespiratory diseases potentially causing the clinical signs. Alveolar surfactant was isolated from frozen, cell-free supernatants of BAL fluid and biophysical analysis of the samples was completed using a constrained sessile drop surfactometer. Statistical comparisons over consecutive compression expansion cycles were performed using repeated measures ANOVA and comparisons of single values between groups were analyzed using T-test.
RESULTS
There were no significant differences between groups in any of the biophysical outcomes of surfactant analysis. The critical function of surfactant, reducing the surface tension to low values upon compression, was similar between healthy dogs and affected drevers.
CONCLUSIONS
The etiology of hunting associated pulmonary edema in drever dogs is not due to an underlying surfactant dysfunction.
Topics: Animals; Dogs; Pulmonary Edema; Dog Diseases; Pulmonary Surfactants; Male; Female; Bronchoalveolar Lavage Fluid; Case-Control Studies
PubMed: 38822358
DOI: 10.1186/s13028-024-00745-x -
American Journal of Respiratory Cell... May 2024Pulmonary fibrosis (PF) can be idiopathic or driven by a specific insult or disease process. Inflammation plays a role in the pathophysiology, the extent of which...
Pulmonary fibrosis (PF) can be idiopathic or driven by a specific insult or disease process. Inflammation plays a role in the pathophysiology, the extent of which remains a longstanding topic of debate. More recently there has been increasing interest in a potential inciting role for aberrant lipid metabolism. Lipids are essential for the structure and function of all cell membranes but specifically in the lung for surfactant composition, intra and intercellular lipid mediators and lipofibroblasts. Clinically, there is evidence of increased lipid deposition in the subpleural space, and at a whole lung tissue level in PF. There is evidence of increased parenchymal lipid deposition and abnormal mediastinal fat shape on chest CT. A protective role for cholesterol lowering drugs including statins and ezetimibe has been described in PF. At a cellular level, fatty acid (FA), phospholipid (PL) and glucose metabolism are disordered, as is the production of lipid mediators. In this perspectives piece we put forward the argument that there is substantive clinical and biological evidence to support a role for aberrant lipid metabolism and lipid mediators in the pathogenesis of PF.
PubMed: 38820234
DOI: 10.1165/rcmb.2024-0124PS