Characteristics of phosgene aspiration lung injury analyzed based on transcriptomics and proteomics.

Background: Phosgene is a chemical material widely used worldwide. No effective method has been developed to reverse its pathological injuries. Some studies have shown that neuronal inflammation in lung tissue is involved, but the specific mechanism has not been reported. Objective: To analyze the expression alterations of whole transcriptome gene sequencing bioinformatics and protein expression profile in lung tissue after phosgene aspiration lung injury (P-ALI) and find the main factors and pathways affecting the prognosis of P-ALI. Methods: Rat models of P-ALI were made by phosgene. Rats were divided into a P-ALI group and a blank group. Hematoxylin-eosin (HE) staining and lung wet/dry ratio measurement were used to evaluate the lung injury. The levels of inflammatory factors were measured by ELISA. High-throughput sequencing was used to measure the expression profile of each gene. Protein expression profiles were determined by label-free relative quantification of the differential proteome. Results: Lung injury such as the disordered structure of alveolar wall and inflammatory factors (IL-1ß, IL-18, and IL-33) were significantly increased in the P-ALI group (p < 0.05). There were 225 differentially expressed lncRNAs, including 85 upregulated and 140 downregulated genes. They were also the genomes with the most significant changes in transcriptome gene expression, mainly constituting cytoplasmic, synaptic structures and transporters, and involved in amino acid and carbon metabolism. There were 42 differentially expressed circRNAs, including 25 upregulated genes and 17 downregulated genes, mainly involved in cell composition, growth, differentiation, and division. There were only 10 differentially expressed miRNAs genes, all upregulated and mainly involved in the inflammatory response pathway. Proteome identification showed 79 differentially expressed proteins. KEGG enrichment analysis showed that it was mainly involved in the N-glycan biosynthesis pathway. Conclusion: We discovered that differentially regulated genes (lncRNAs, circRNAs, and miRNAs) were primarily associated with neuronal reflexes and synaptic signaling, including neurotransmitter transmission, ion signaling pathway conduction, neuronal projection, and synaptic vesicle circulation. They affected inflammatory factors and other metabolic pathways. This finding could be explored in future studies.

High throughput sequencing technology reveals alteration of lower respiratory tract microbiome in severe aspiration pneumonia and its association with inflammation.

BACKGROUND: Aspiration pneumonia is a common and severe clinical condition. The microbiome present in the lower respiratory tract plays a crucial role in regulating human inflammatory response. However, the relationship between the altered lower respiratory tract microbiome and inflammation in aspiration pneumonia remains inadequately explored. PURPOSE: To investigate the alteration of the lower respiratory tract microbiome in severe aspiration pneumonia patients and explore the potential correlation between microbiome components and inflammatory response. METHOD: Patients in the severe aspiration pneumonia group and control group were enrolled from the intensive care unit of Jinshan Hospital, Fudan University between December 31, 2020 and August 19, 2021. Sputum specimens were collected from all participants and subsequently subjected to 16S rDNA high throughput sequencing technology. The concentration of inflammatory cytokines in serum was measured using enzyme-linked immunosorbent assay (ELISA) kits, and collected data including patients' demographic information, clinical data, and laboratory examination results were recorded for further analysis. RESULTS: Alteration in the lower respiratory tract microbiome was observed in severe aspiration pneumonia. Compared to the control group, a significant decrease in the relative abundance of Firmicutes was found at the phylum level (P < 0.01). At the family level, the relative abundance of Corynebacteriaceae, Enterobacteriaceae and Enterococcaceae increased significantly (P < 0.001, P < 0.05, P < 0.01). There were no significant differences in community diversity of the lower respiratory tract between the two groups. Patients in the severe aspiration pneumonia group exhibited significantly higher levels of inflammation compared to those in the control group. Correlation analysis showed that the relative abundance of Corynebacteriaceae was positively correlated with the expression level of IL-1ß and IL-18 (P = 0.002, P = 0.02); the relative abundance of Enterobacteriaceae was negatively correlated with IL-4 (P = 0.011); no other significant correlations have been identified between microbiome and inflammatory indicators thus far (P > 0.05). CONCLUSIONS: Alteration of the lower respiratory tract microbiome is critically involved in inflammation and disease progression in severe cases of aspiration pneumonia. The potential inflammation regulation properties of the microbiome hold promising value for developing novel therapeutic approaches aimed at mitigating the severity of the disease.

Advancing Treatment Strategies: A Comprehensive Review of Drug Delivery Innovations for Chronic Inflammatory Respiratory Diseases.

Chronic inflammatory respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis, present ongoing challenges in terms of effective treatment and management. These diseases are characterized by persistent inflammation in the airways, leading to structural changes and compromised lung function. There are several treatments available for them, such as bronchodilators, immunomodulators, and oxygen therapy. However, there are still some shortcomings in the effectiveness and side effects of drugs. To achieve optimal therapeutic outcomes while minimizing systemic side effects, targeted therapies and precise drug delivery systems are crucial to the management of these diseases. This comprehensive review focuses on the role of drug delivery systems in chronic inflammatory respiratory diseases, particularly nanoparticle-based drug delivery systems, inhaled corticosteroids (ICSs), novel biologicals, gene therapy, and personalized medicine. By examining the latest advancements and strategies in these areas, we aim to provide a thorough understanding of the current landscape and future prospects for improving treatment outcomes in these challenging conditions.

Acidophilic methanotrophs: Occurrence, diversity, and possible bioremediation applications.

Methanotrophs have been identified and isolated from acidic environments such as wetlands, acidic soils, peat bogs, and groundwater aquifers. Due to their methane (CH4 ) utilization as a carbon and energy source, acidophilic methanotrophs are important in controlling the release of atmospheric CH4 , an important greenhouse gas, from acidic wetlands and other environments. Methanotrophs have also played an important role in the biodegradation and bioremediation of a variety of pollutants including chlorinated volatile organic compounds (CVOCs) using CH4 monooxygenases via a process known as cometabolism. Under neutral pH conditions, anaerobic bioremediation via carbon source addition is a commonly used and highly effective approach to treat CVOCs in groundwater. However, complete dechlorination of CVOCs is typically inhibited at low pH. Acidophilic methanotrophs have recently been observed to degrade a range of CVOCs at pH < 5.5, suggesting that cometabolic treatment may be an option for CVOCs and other contaminants in acidic aquifers. This paper provides an overview of the occurrence, diversity, and physiological activities of methanotrophs in acidic environments and highlights the potential application of these organisms for enhancing contaminant biodegradation and bioremediation.

PTTG1 promotes CD34+CD45+ cells to repair the pulmonary vascular barrier via activating the VEGF-bFGF/PI3K/AKT/eNOS signaling pathway in rats with phosgene-induced acute lung injury.

Accidental exposure to phosgene can cause acute lung injury (ALI), characterized by uncontrolled inflammation and impaired lung blood-gas barrier. CD34+CD45+ cells with high pituitary tumor transforming gene 1 (PTTG1) expression were identified around rat pulmonary vessels through single-cell RNA sequencing, and have been shown to attenuate P-ALI by promoting lung vascular barrier repair. As a transcription factor closely related to angiogenesis, whether PTTG1 plays a role in CD34+CD45+ cell repairing the pulmonary vascular barrier in rats with P-ALI remains unclear. This study provided compelling evidence that CD34+CD45+ cells possess endothelial differentiation potential. Rats with P-ALI were intratracheally administered with CD34+CD45+ cells transfected with or without PTTG1-overexpressing and sh-PTTG1 lentivirus. It was found that CD34+CD45+ cells reduced the pulmonary vascular permeability and mitigated the lung inflammation, which could be reversed by knocking down PTTG1. Although PTTG1 overexpression enhanced the ability of CD34+CD45+ cells to attenuate P-ALI, no significant difference was found. PTTG1 was found to regulate the endothelial differentiation of CD34+CD45+ cells. In addition, knocking down of PTTG1 significantly reduced the protein levels of VEGF and bFGF, as well as their receptors, which in turn inhibited the activation of the PI3K/AKT/eNOS signaling pathway in CD34+CD45+ cells. Moreover, LY294002 (PI3K inhibitor) treatment inhibited the endothelial differentiation of CD34+CD45+ cells, while SC79 (AKT activator) yielded the opposite effect. These findings suggest that PTTG1 can promote the endothelial differentiation of CD34+CD45+ cells by activating the VEGF-bFGF/PI3K/AKT/eNOS signaling pathway, leading to the repair of the pulmonary vascular barrier in rats with P-ALI.

Early platelet level reduction as a prognostic factor in intensive care unit patients with severe aspiration pneumonia.

Introduction: This study investigates risk factors underlying the prognosis of severe aspiration pneumonia (SAP) in intensive care unit (ICU) patients and attempts to provide early prognosis reference for clinical tasks. Methods: Patients diagnosed with SAP and admitted to the ICU of Jinshan Hospital, Fudan University, Shanghai, China, between January 2021 and December 2021 were recruited in this retrospective cohort study. Clinical data on a patient's general condition, underlying diseases, laboratory indicators, and 90-day outcomes (survival or death) were recorded. Results: Multivariate logistic regression analysis showed that a low platelet count was an independent risk factor affecting the prognosis of death (OR = 6.68, 95% CI:1.10-40.78, ß = 1.90, P = 0.040). Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive value of variables; cut-off values were calculated and the area under the curve was 0.7782 [(95% CI:0.686-0.871), p < 0.001] for the prediction of death at 90 days in all patients. The Kaplan-Meier curve used for survival analysis showed that, compared with the normal platelet group, the overall survival rate of patients with low platelet levels was significantly lower, and the difference was statistically significant [HR = 2.11, (95% CI:1.47-3.03), p = 0.0001, z = 4.05, X 2 = 14.89]. Cox regression analysis, used to further verify the influence of prognostic risk factors, showed that a concurrent low platelet count was the most important independent risk factor affecting the prognosis of SAP (HR = 2.12 [95% CI:1.12-3.99], X2 = 50.95, p = 0.021). Conclusion: These findings demonstrate an association between SAP mortality and platelet levels on admission. Thus, platelet level at admission may be used as a readily available marker for assessing the prognosis of patients with SAP.

RGD-Hydrogel Improves the Therapeutic Effect of Bone Marrow-Derived Mesenchymal Stem Cells on Phosgene-Induced Acute Lung Injury in Rats.

Mesenchymal stem cells (MSCs) have promising potential in the treatment of various diseases, such as the therapeutic effect of bone marrow-derived MSCs for phosgene-induced acute lung injury (P-ALI). However, MSC-related therapeutics are limited due to poor cell survival, requiring appropriate MSC delivery systems to maximise therapeutic capacity. Biomaterial RGD-hydrogel is a potential cell delivery vehicle as it can mimic the natural extracellular matrix and provide cell adhesion support. The application of RGD-hydrogel in the MSC treatment of respiratory diseases is scarce. This study reports that RGD-hydrogel has good biocompatibility and can increase the secretion of Angiopoietin-1, hepatocyte growth factor, epidermal growth factor, vascular endothelial cell growth factor, and interleukin-10 in vitro MSCs. The hydrogel-encapsulated MSCs could further alleviate P-ALI and show better cell survival in vivo. Overall, RGD-hydrogel could improve the MSC treatment of P-ALI by modulating cell survival and reparative activities. It is exciting to see more and more ways to unlock the therapeutic potential of MSCs.

Percutaneous coronary intervention in insulin-treated diabetic patients: A meta-analysis.

BACKGROUND: This meta-analysis of randomized controlled trials (RCTs) compared long-term adverse clinical outcomes of percutaneous coronary intervention (PCI) in insulin-treated diabetes mellitus (ITDM) and non-ITDM patients. METHODS: This is a meta-analysis study. The PubMed and Embase databases were searched for articles on long-term adverse clinical outcomes of PCI in ITDM and non-ITDM patients. The risk ratios (RR) and 95% confidence intervals (CI) were calculated. RESULTS: A total of 11 related RCTs involving 8853 DM patients were included. Compared with non-ITDM patients, ITDM patients had significantly higher all-cause mortality (ACM) (RR = 1.52, 95% CI: 1.25-1.85, pheterogeneity  = .689, I2  = 0%), major adverse cardiac and cerebrovascular events (MACCE) (RR = 1.35, 95% CI: 1.18-1.55, pheterogeneity  = .57, I2  = 0%), myocardial infarction (MI) (RR = 1.41, 95% CI: 1.16-1.72, pheterogeneity  = .962, I2  = 0%), and stent thrombosis (ST) (RR = 1.75, 95% CI: 1.23-2.48, pheterogeneity  = .159, I2  = 32.4%). No significant difference was found in the target lesion revascularization (TLR) and target vessel revascularization (TVR) between the ITDM and non-ITDM groups. CONCLUSIONS: The results showed that ITDM patients had significantly higher ACM, MACCE, MI, and ST, compared with non-ITDM patients.

Dietary calcium pyruvate could improve growth performance and reduce excessive lipid deposition in juvenile golden pompano (Trachinotus ovatus) fed a high fat diet.

Excessive lipid deposition in farmed fish is a challenge in the aquaculture industry. To study the effect of dietary calcium pyruvate (CaP) on lipid accumulation in fish, we used a high fat diet (HFD) to establish a lipid accumulation model in juvenile golden pompano (Trachinotus ovatus) and supplemented with 0%, 0.25%, 0.50%, 0.75% and 1.0% CaP (diets D0-D4, respectively). After 8-week feeding in floating cages, dietary CaP significantly improved growth performance, which peaked in fish fed diet D3. Supplementation of CaP significantly decreased whole body lipid content in fish fed D2-D4 and hepatosomatic index and liver lipid content in fish fed D3 and D4. Serum and hepatic antioxidant indices, including glutathione, catalase and superoxide dismutase, showed generally increasing trends in fish fed diets with CaP. In addition, increasing dietary CaP increasingly reduced hepatic activities of hexokinase, phosphofructokinase and pyruvate kinase involved in glycolysis, and increased glycogen contents of the liver and muscle. Dietary CaP up-regulated the liver mRNA expression of pparα, cpt1, hsl and fabp1, but down-regulated expression of srebp-1, fas and acc. In conclusion, 0.75% CaP improved growth performance and reduced excessive lipid deposition by affecting fatty acid synthesis and lipolysis in juvenile T. ovatus fed HFD.

NEDD4 attenuates phosgene-induced acute lung injury through the inhibition of Notch1 activation.

Phosgene gas leakage can cause life-threatening acute lung injury (ALI), which is characterized by inflammation, increased vascular permeability, pulmonary oedema and oxidative stress. Although the downregulation of neuronal precursor cell-expressed developmentally downregulated 4 (NEDD4) is known to be associated with inflammation and oxidative damage, its functions in phosgene-induced ALI remain unclear. In this study, rats with phosgene-induced ALI were intravenously injected with NEDD4-overexpressing lentiviruses to determine the functions of NEDD4 in this inflammatory condition. NEDD4 expression was decreased in the lung parenchyma of phosgene-exposed control rats, whereas its expression level was high in the NEDD4-overexpressing rats. Phosgene exposure increased the wet-to-dry lung weight ratio, but NEDD4 abrogated this effect. NEDD4 overexpression attenuated phosgene-induced lung inflammation, lowering the high lung injury score (based on total protein, inflammatory cells and inflammatory factors in bronchoalveolar lavage fluid) and also reduced phosgene-induced oxidative stress and cell apoptosis. Finally, NEDD4 was found to interact with Notch1, enhancing its ubiquitination and thereby its degradation, thus attenuating the inflammatory responses to ALI. Therefore, we demonstrated that NEDD4 plays a protective role in alleviating phosgene-induced ALI, suggesting that enhancing the effect of NEDD4 may be a new approach for treating phosgene-induced ALI.

Single-Cell RNA-Sequencing Reveals Epithelial Cell Signature of Multiple Subtypes in Chemically Induced Acute Lung Injury.

Alveolar epithelial cells (AECs) play a role in chemically induced acute lung injury (CALI). However, the mechanisms that induce alveolar epithelial type 2 cells (AEC2s) to proliferate, exit the cell cycle, and transdifferentiate into alveolar epithelial type 1 cells (AEC1s) are unclear. Here, we investigated the epithelial cell types and states in a phosgene-induced CALI rat model. Single-cell RNA-sequencing of bronchoalveolar lavage fluid (BALF) samples from phosgene-induced CALI rat models (Gas) and normal controls (NC) was performed. From the NC and Gas BALF samples, 37,245 and 29,853 high-quality cells were extracted, respectively. All cell types and states were identified and divided into 23 clusters; three cell types were identified: macrophages, epithelial cells, and macrophage proliferating cells. From NC and Gas samples, 1315 and 1756 epithelial cells were extracted, respectively, and divided into 11 clusters. The number of AEC1s decreased considerably following phosgene inhalation. A unique SOX9-positive AEC2 cell type that expanded considerably in the CALI state was identified. This progenitor cell type may develop into alveolar cells, indicating its stem cell differentiation potential. We present a single-cell genome-scale transcription map that can help uncover disease-associated cytologic signatures for understanding biological changes and regeneration of lung tissues during CALI.

Lung-derived exosomes regulate the function of mesenchymal stem cells and alleviate phosgene-induced lung injury via miR-34c-3p.

Phosgene may induce acute lung injury (ALI) when a person is exposed to it. Mesenchymal stem cells (MSCs) were affirmed to have therapeutic effects on phosgene-induced ALI. In a previous study, ALI exosomes have been confirmed to promote the proliferation and migration of MSCs. However, the mechanism of this phenomenon is still unclear. MicroRNAs (miRNAs) are essential in the physiological process of cells. In this study, lung-derived exosomes were isolated from phosgene-exposed and normal rats, respectively, through ultracentrifugation and cultured MSCs with these exosomes. We found that rno-miR-34c-3p was downregulated in MSCs cocultured with ALI exosomes. MiR-34c-3p inhibitor promoted the proliferation and migration of MSCs. Moreover, the dual-luciferase reporter assay demonstrated that miR-34c-3p regulated Janus kinase 1 (JAK1) expression. The miR-34c-3p inhibitor also significantly activated the JAK1/signal transducer and activator of transcription 3 (STAT3) signaling pathway. In conclusion, ALI exosomes decrease the miR-34c-3p expression levels, influencing MSCs via the JAK1/STAT3 signaling pathway.

Comprehensive Analysis of the Profiles of Differentially Expressed mRNAs, lncRNAs, and circRNAs in Phosgene-Induced Acute Lung Injury.

Phosgene exposure can cause acute lung injury (ALI), for which there is no currently available effective treatment. Mesenchymal stem cells (MSCs) which have been proven to have therapeutic potential and be helpful in the treatment of various diseases, but the mechanisms underlying the function of MSCs against phosgene-induced ALI are still poorly explored. In this study, we compared the expression profiles of mRNAs, lncRNAs, and circRNAs in the lung tissues from rats of three groups-air control (group A), phosgene-exposed (group B), and phosgene + MSCs (group C). The results showed that 389 mRNAs, 198 lncRNAs, and 56 circRNAs were differently expressed between groups A and B; 130 mRNAs, 107 lncRNAs, and 35 circRNAs between groups A and C; and 41 mRNAs, 88 lncRNAs, and 18 circRNAs between groups B and C. GO and KEGG analyses indicated that the differentially expressed RNAs were mainly involved in signal transduction, immune system processes, and cancers. In addition, we used a database to predict target microRNAs (miRNAs) interacting with circRNAs and the R network software package to construct a circRNA-targeted miRNA gene network map. Our study showed new insights into changes in the RNA expression in ALI, contributing to explore the mechanisms underlying the therapeutic potential of MSCs in phosgene-induced ALI.

NLRP3 gene silencing ameliorates phosgene-induced acute lung injury in rats by inhibiting NLRP3 inflammasome and proinflammatory factors, but not anti-inflammatory factors.

NOD-like receptor protein 3 (NLRP3) is involved in acute lung injury (ALI), but its exact role in phosgene-induced ALI is not clearly understood. The aim of the study is to explore the potential therapeutic effect of NLRP3 inflammasome modulation in the management of phosgene-induced ALI. ALI was induced in rats by phosgene exposure at 8.33 g/m3 for 5 min, 30 hr before intravenous injection of adenovirus-NLRP3 shRNA (Ad/NLRP3-shRNA). The histological changes in the lung were evaluated. Bronchoalveolar lavage fluid (BALF) neutrophils were counted (smear), and protein content was measured using the BCA assay. The wet/dry ratio of lung tissue (W/D) was measured. TUNEL staining for DNA damage was used to indirectly assess pyroptosis. NLRP3 inflammasome was assessed by immunohistochemistry, RT-PCR, western blotting. Cytokines were measured by ELISA. Histological analyses revealed reduced severity in phosgene-induced ALI with Ad/NLRP3-shRNA pretreatment. TUNEL staining indicated decreased pyroptosis in Psg-Ad/NLRP3-shRNA rats. Decreased mRNA and protein levels of NLRP3 and caspase-1 (all P < 0.05), but not ASC (P > 0.05), were found in Psg-Ad/NLRP3-shRNA rats. Immunohistochemistry revealed that Ad/NLRP3-shRNA pretreatment inhibited NLRP3 inflammasome activation. Reduced level of pro-inflammatory interleukin (IL)-1ß, IL-18, IL-33, and tumor necrosis factor (TNF)-α (all P < 0.05), but not of anti-inflammatory IL-4 and IL-10 (all P > 0.05), were found in serum and BALF from Ad/NLRP3-shRNA rats. NLRP3 gene silencing exerts beneficial effects on phosgene-induced lung injury by inhibiting NLRP3 inflammasome activation and pro-inflammatory factors, but not anti-inflammatory factors. Disruption of NLRP3 inflammasome activation might be used as a therapeutic modality for the treatment of phosgene-induced ALI.

From Organic Wastes to Bioplastics: Feasibility of Nonsterile Poly(3-hydroxybutyrate) Production by Zobellella denitrificans ZD1.

Poly(3-hydroxybutyrate) (PHB)-a renewable and biodegradable polymer-is a promising alternative to nonbiodegradable synthetic plastics that are derived from petrochemicals. The methods currently employed for PHB production are costly, in part, due to the expensive cultivation feedstocks and the need to sterilize the culture medium, which is energy-intensive. This study investigates the feasibility of nonsterile PHB production from several saline organic wastes using a salt-tolerant strain, Zobellella denitrificans ZD1 (referred to as strain ZD1). Factors such as the pH, salinity, carbon/nitrogen (C/N) ratio, nitrogen source, and electron acceptor that might affect the growth of strain ZD1 and its PHB production were determined. Our results showed successful nonsterile PHB production by growing the strain ZD1 on nonsterile synthetic crude glycerol, high-strength saline wastewater, and real municipal wastewater-activated sludge under saline conditions. The PHB production was significantly enhanced when the levels of salts and nitrate-nitrogen in the culture medium were increased. This study suggested a promising low-cost nonsterile PHB production strategy from organic wastes using strain ZD1.

Protective role of mesenchymal stem cells transfected with miRNA-378a-5p in phosgene inhalation lung injury.

Phosgene-induced lung injury is an important type of acute lung injury (ALI). Currently, no effective clinical treatment has been developed yet. Our previous study revealed that expressions of 6 miRNAs were significantly increased in phosgene-induced lung injury. The screened miRNA with the most significant effect on hepatocyte growth factor (HGF) expression by mesenchymal stem cells (MSCs) was transfected into MSCs. This study aimed to investigate whether the transfected MSCs had better therapeutic effects than MSCs alone. MSCs were co-cultured with miRNA mimics for 24h and 48h. HGF expression in culture supernatant was detected by ELISA. HGF expression in MSCs was detected by Western blot after being co-cultured with the selected miRNA inhibitor. The transfected MSCs were given to rats suffering from phosgene-induced lung injury. Expressions of TNF-α, IL-6, IL-1ß and IL-10, were assayed by ELISA. SP-C mRNA level was tested by RT-PCR. VE-CAD expression was tested by Western blot. We found that miRNA-378a-5p most increased HGF expression among the six miRNAs. After transfection of MSCs with miRNA-378a-5p inhibitor, HGF expression was decreased. Compared with untreated MSCs, MSCs transfected with miRNA-378a-5p exhibited more significant decreases in lung injury score, white blood cell count and protein content while restoring respiratory indexes. Meanwhile, expressions of TNF-α, IL-6, IL-1ß were decreased while those of IL-10, SP-C and VE-cadherin were increased. In conclusion, MSCs transfected with miRNA-378a-5p were more effective in treating phosgene-induced lung injury by repairing the secretion of alveolar epithelial cells and improving the permeability of vascular endothelial cells compared with MSCs alone.

Lung-derived exosomes in phosgene-induced acute lung injury regulate the functions of mesenchymal stem cells partially via miR-28-5p.

Accidental phosgene exposure can result in acute lung injury (ALI). Mesenchymal stem cells (MSCs) have been found to alleviate phosgene-induced ALI. However, the mechanism of MSCs underlying such protective effect remains largely unexplored. Exosomes, important components of microenvironment, are closely associated with intercellular information transfer. In the present study, we isolated lung exosomes in rats after phosgene exposure by ultracentrifugation and explored their effects on MSCs in vitro. ALI exosomes were elliptical in shape and 50-200 nm in size. ALI exosomes could promote proliferation and migration of MSCs. Moreover, ALI exosomes increased the secretion of IL-10, leading to enhanced immunoregulatory properties of MSCs. The paracrine factors, VEGF, HGF, LL-37 and Ang-1, were also augmented by ALI exosomes. However, ALI exosomes had no effect on differentiation of MSCs towards lung alveolar cells. To identify the effective miRNAs in ALI exosomes, we performed miRNA profile analysis. MiR-28-5p was considered as a possible effective molecule. We further studied the effect of miR-28-5p on MSCs. MiR-28-5p mimic promoted proliferation, migration, immunomodulation of MSCs. MiR-28-5p mimic promoted the paracrine of VEGF, HGF, LL-37 and Ang-1. Besides, we explored molecular mechanism of miR-28-5p in MSCs. PI3K/Akt signaling pathway was found significantly augmented by miR-28-5p mimic, indicating the activation in this process. Taken together, our findings could help identify the effects of lung-derived exosomes on MSCs, and the effective molecule in exosomes, miR-28-5p, activated MSCs through PI3K/Akt signaling pathway.

Mesenchymal stem cell-derived exosomes attenuate phosgene-induced acute lung injury in rats.

Objective: We have previously found that mesenchymal stem cell (MSC) therapy can ameliorate phosgene-induced acute lung injury (ALI). Moreover, exosomes can be used as a cell-free alternative therapy. In the present study, we aimed to assess the effect of MSC-derived exosomes on phosgene-induced ALI. Methods: MSC-derived exosomes were isolated from MSCs through ultracentrifugation. Sprague-Dawley (SD) rats were exposed to phosgene at 8.33 g/m3 for 5 min. MSC-derived exosomes were intratracheally administered and rats were sacrificed at the time points of 6, 24 and 48 h. Results: Compared with the phosgene group, MSC-derived exosomes reversed respiratory function alterations, showing increased levels of TV, PIF, PEF and EF50 as well as decreased levels of RI and EEP. Furthermore, MSC-derived exosomes improved pathological alterations and reduced wet-to-dry ratio and total protein content in BALF. MSC-derived exosomes reduced the levels of TNF-α, IL-1ß and IL-6 and increased the IL-10 level in BALF and plasma. MSC-derived exosomes suppressed the MMP-9 level and increased the SP-C level. Conclusions: MSC-derived exosomes exerted beneficial effects on phosgene-induced ALI via modulating inflammation, inhibiting MMP-9 synthesis and elevating SP-C level.

Exogenous mesenchymal stem cells affect the function of endogenous lung stem cells (club cells) in phosgene-induced lung injury.

Exogenous mesenchymal stem cells (MSCs) affect lung cells via cytokines as well as vesicles and activate the Notch signaling pathway thus affecting the proliferation of endogenous stem cells to repair damaged tissue. Club cells are endogenous lung stem cells whose proliferation is also closely related to the Notch signaling pathway. The club cell secretory protein (CCSP) has anti-inflammatory and anti-oxidative properties. This study aimed to investigate whether exogenous MSCs affect the function of club cells in an injured lung and whether these effects are related to the Notch signaling pathway. CCSP levels in bronchoalveolar lavage fluid (BALF) and serum were evaluated using enzyme-linked immunosorbent assay (ELISA) and the average fluorescence intensity (AFI) of CCSP in club cells was determined using flow cytometry. Immunohistochemistry and immunofluorescence were used to visualize club cells and proliferative club cells. The expression of important Notch signaling pathway components including Notch1∼4, c-myc, Hey1 and Hes1 were also assessed. LY3039478 (LY), a specific inhibitor of the Notch signaling pathway, was applied. After MSCs intervention, CCSP levels decreased, and club cell AFI increased, indicating that the secretion of club cells had weakened. The expression of Notch1, Notch2, c-myc, Hey1, Hes1 increased, accompanied by an increase in the number of proliferative club cells. Furthermore, MSCs enhanced the proliferation of club cells, while LY suppressed this phenomenon. In summary, MSCs reduced the secretion of club cells. And MSCs enhanced the proliferation of club cells partly via activating the Notch signaling pathway, which promoted lung injury repair.

Evaluation of methanotrophic bacterial communities capable of biodegrading trichloroethene (TCE) in acidic aquifers.

While bioremediation technologies for trichloroethene (TCE), a suspected carcinogen, have been successfully demonstrated in neutral pH aquifers, these technologies are often ineffective for remediating TCE contamination in acidic aquifers (i.e., pH < 5.5). Acidophilic methanotrophs have been detected in several low pH environments, but their presence and potential role in TCE degradation in acidic aquifers is unknown. This study applied a stable isotope probing-based technique to identify active methanotrophs that are capable of degrading TCE in microcosms prepared from two low pH aquifers. A total of thirty-five clones of methanotrophs were derived from low pH microcosms in which methane and TCE degradation had been observed, with 29 clustered in γ-Proteobacteria and 6 clustered in α-Proteobacteria. None of the clones has a high similarity to known acidophilic methanotrophs from other environments. The presence and diversity of particulate MMO and soluble MMO were also investigated. The pmoA gene was detected predominantly at one site, and the presence of a specific form of mmoX in numerous samples suggested that Methylocella spp. may be common in acidic aquifers. Finally, a methane-grown culture at pH 4 was enriched from an acidic aquifer and its ability to biodegrade various chlorinated ethenes was tested. Interestingly, the mixed culture rapidly degraded TCE and vinyl chloride, but not cis-dichloroethene after growth on methane. The data suggest that aerobic biodegradation of TCE and other chlorinated solvents in low pH groundwater may be facilitated by methanotrophic bacteria, and that there are potentially a wide variety of different strains that inhabit acidic aquifers.