Arsenic induces ferroptosis and acute lung injury through mtROS-mediated mitochondria-associated endoplasmic reticulum membrane dysfunction.

The goal of this study was to analyze whether mitochondria-associated endoplasmic reticulum membrane (MAMs) dysfunction mediated arsenic (As)-evoked pulmonary ferroptosis and acute lung injury (ALI). As exposure led to alveolar structure damage, inflammatory cell infiltration and pulmonary function decline in mice. Ferritin, the marker of iron overload, was increased, GPX4, the index of lipid peroxidation, was decreased in As-exposed lungs and pulmonary epithelial cells (MLE-12). Pretreatment with ferrostatin-1 (Fer-1), the inhibitor of ferroptosis, alleviated As-evoked ALI. In addition, As-induced non-heme iron deposition was inhibited in Fer-1 pretreated-mice. Moreover, As-triggered mitochondria damage and ferroptosis were mitigated in Fer-1 pretreated-MLE-12 cells. Mechanistically, PERK phosphorylation and mitofusin-2 (Mfn-2) reduction was observed in As-exposed MLE-12 cells and mice lungs. Additionally, the interaction between PERK and Mfn-2 was downregulated and MAMs dysfunction was observed in As-exposed MLE-12 cells. Intriguingly, PERK inhibitor and Mfn-2-overexpression all mitigated As-induced ferroptosis in MLE-12 cells. Additionally, CLPP and mtHSP70, the markers of mitochondrial stress, were upregulated, mitochondrial ROS (mtROS) was elevated, mitochondrial membrane potential (MMP) and ATP were decreased in As-exposed MLE-12 cells. Mitoquinone mesylate (MitoQ), a novel mitochondrial-targeted antioxidant, alleviated As-induced excess mtROS, mitochondrial stress, MAMs dysfunction in pulmonary epithelial cells. Similarly, in vivo experiments indicated that MitoQ pretreatment countered As-induced pulmonary ferroptosis and ALI. These data indicated that mtROS-initiated MAMs dysfunction is, at least partially, implicated in As-evoked ferroptosis and ALI.

Renal dysfunction and prognosis of COVID-19 patients: a hospital-based retrospective cohort study.

INTRODUCTION: Increasing evidence indicate that coronavirus disease 2019 (COVID-19) is companied by renal dysfunction. However, the association of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2)-induced renal dysfunction with prognosis remains obscure. MATERIALS AND METHODS: All 154 patients with COVID-19 were recruited from the Second People's Hospital of Fuyang City in Anhui, China. Demographic characteristics and laboratory data were extracted. Renal dysfunction was evaluated and its prognosis was followed up based on a retrospective cohort study. RESULTS: There were 125 (81.2%) mild and 29 (18.8%) severe cases in 154 COVID-19 patients. On admission, 16 (10.4%) subjects were accompanied with renal dysfunction. Serum creatinine and cystatin C were increased and estimated glomerular filtration rate (eGFR) was decreased in severe patients compared with those in mild patients. Renal dysfunction was more prevalent in severe patients. Using multivariate logistic regression, we found that male gender, older age and hypertension were three importantly independent risk factors for renal dysfunction in COVID-19 patients. Follow-up study found that at least one renal function marker of 3.33% patients remained abnormal in 2 weeks after discharge. CONCLUSION: Male elderly COVID-19 patients with hypertension elevates the risk of renal dysfunction. SARS-CoV-2-induced renal dysfunction are not fully recovered in 2 weeks after discharge.

The associations of serum S100A9 with the severity and prognosis in patients with community-acquired pneumonia: a prospective cohort study.

BACKGROUND: Previous studies found that S100A9 may involve in the pathophysiology of community-acquired pneumonia (CAP). However, the role of S100A9 was unclear in the CAP. The goal was to explore the correlations of serum S100A9 with the severity and prognosis of CAP patients based on a prospective cohort study. METHODS: A total of 220 CAP patients and 110 control subjects were recruited. Demographic and clinical data were collected. Serum S100A9 and inflammatory cytokines were measured. RESULTS: Serum S100A9 was elevated in CAP patients on admission. Serum S100A9 was gradually elevated parallelly with CAP severity scores. Additionally, inflammatory cytokines were increased and blood routine parameters were changed in CAP patients compared with control subjects. Correlation analysis found that serum S100A9 was positively associated with CAP severity scores, blood routine parameters (WBC, NLR and MON) and inflammatory cytokines. Further, logistic regression analysis demonstrated that there were positive associations between serum S100A9 and CAP severity scores. Besides, the prognosis of CAP was tracked. Serum higher S100A9 on the early stage elevated the death of risk and hospital stay among CAP patients. CONCLUSION: Serum S100A9 is positively correlated with the severity of CAP. On admission, serum higher S100A9 elevates the risk of death and hospital stay in CAP patients, suggesting that S100A9 may exert a certain role in the pathophysiology of CAP and regard as a serum diagnostic and managing biomarker for CAP.

Correlations among Pulmonary DJ-1, VDR and Nrf-2 in patients with Chronic Obstructive Pulmonary Disease: A Case-control Study.

Parkinson protein 7 (PARK7)/DJ-1 (DJ-1) is a redox sensitive molecular and stabilizer of nuclear factor erythroid 2-related factor 2 (Nrf-2). Nrf-2 regulates the downstream antioxidant defense system and exerts a significant function in patients with chronic obstructive pulmonary disease (COPD). Vitamin D receptor (VDR) is the nuclear receptor that regulates the downstream target genes. This study aimed to analyze the associations among pulmonary function, DJ-1, VDR and Nrf-2 in COPD patients. Serum was collected from 180 COPD patients and control subjects. Thirty-five lung tissues were obtained. DJ-1 was measured using ELISA and western blotting. Nrf-2 and VDR were detected by immunohistochemistry. Serum and pulmonary DJ-1 levels were lower in COPD patients than those in control subjects. Pulmonary VDR-positive nuclei were reduced in COPD patients. Nrf-2-positive nuclei were reduced in lung tissues of COPD patients. On the contrary, Nrf-2-related downstream target proteins were elevated in COPD patients. Further correlation analysis indicated that forced expiratory volume in 1 second (FEV1) was positively associated with pulmonary DJ-1, VDR and Nrf-2 in patients with COPD. In addition, there were positive correlations among DJ-1, VDR and Nrf-2 in lung tissues of COPD patients. In conclusion, DJ-1, VDR and Nrf-2 were decreased in COPD patients compared with control subjects. The reduction of DJ-1 and VDR associating with Nrf-2 downregulation may be involved in the process of COPD.

Association Between Serum S100A8/S100A9 Heterodimer and Pulmonary Function in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

BACKGROUND: Many studies have indicated that S100A8 and S100A9 may be involved in the development and progression of chronic obstructive pulmonary disease (COPD). However, there has been no clinical study analyzing the role of the serum S100A8/S100A9 heterodimer in COPD patients. The aim of this study was to analyze the correlation of the serum S100A8/S100A9 heterodimer with pulmonary function in COPD patients during acute exacerbation (AE-COPD) based on a cross-sectional study. METHODS: A total of 131 AE-COPD patients and matched healthy subjects were recruited. Pulmonary function, arterial blood gas values, and serum inflammatory cytokines were measured. RESULTS: Serum S100A8/S100A9 was increased in AE-COPD patients. AE-COPD patients were ranked into different grades based on FEV1%. Serum S100A8/S100A9 was higher in Grade 4 than in Grade 1-2 and Grade 3 patients with AE-COPD. Univariate regression analysis found that serum S100A8/S100A9 was negatively correlated with FEV1% in AE-COPD patients. Furthermore, serum S100A8/S100A9 was positively associated with MCP-1 in AE-COPD patients. Further stratified analysis revealed that serum S100A8/S100A9 was negatively associated with FEV1/FVC in Grade 3 (OR 0.629, P < 0.05) and in Grade 4 (OR 0.347, P < 0.05). In addition, there was a positive relationship between serum S100A8/S100A9 and PaCO2 in Grade 3 (OR 1.532, P < 0.05) and Grade 4 (OR 1.925, P < 0.01). CONCLUSION: S100A8/S100A9 was negatively associated with pulmonary function in AE-COPD patients, indicating that the serum S100A8/S100A9 heterodimer may be involved in the progression of AE-COPD, and may be a relevant serum biomarker in the diagnosis for AE-COPD.

Acute 1-NP exposure induces inflammatory responses through activating various inflammatory signaling pathways in mouse lungs and human A549 cells.

1-Nitropyrene (1-NP), a key component of fine particulate matter (PM2.5), is a representative of nitrated polycyclic aromatic hydrocarbons (NPAHs). The aim of this research is to investigate proinflammatory effects of acute 1-NP exposure in mouse lungs and human A549 cells. All mice except controls were intratracheally instilled with 1-NP (20 µg/mouse). A549 cell, a human lung cancer cell line, was cultured with or without 1-NP (5 µM). Acute 1-NP exposure elevated lung weight and caused infiltration of inflammatory cells, especially neutrophils in mouse lungs. Although it had little effect on serum TNF-α and KC, acute 1-NP exposure elevated the levels of TNF-α and KC in BALF. Correspondingly, acute 1-NP exposure upregulated pulmonary Il-1ß, Il-6, Tnf-α and Kc. Mechanistically, acute 1-NP exposure activated nuclear factor kappa B (NF-κB) in mouse lungs and human A549 cells. Additionally, acute 1-NP exposure induced Akt phosphorylation in mouse lungs and human A549 cells. Moreover, acute 1-NP exposure induced phosphorylation of pulmonary JNK and ERK1/2, molecules of the mitogen-activated protein kinase (MAPK) pathway. This study provides evidence that acute 1-NP exposure induces inflammatory responses through activating various inflammatory signaling pathways in mouse lungs and human A549 cells.

Benzo[a]pyrene evokes epithelial-mesenchymal transition and pulmonary fibrosis through AhR-mediated Nrf2-p62 signaling.

Benzo[a]pyrene (BaP) and its metabolic end product benzo(a)pyren-7,8-dihydrodiol-9,10-epoxide (BPDE), are known toxic environmental pollutants. This study aimed to analyze whether sub-chronic BPDE exposure initiated pulmonary fibrosis and the potential mechanisms. In this work, male C57BL6/J mice were exposed to BPDE by dynamic inhalation exposure for 8 weeks. Our results indicated that sub-chronic BPDE exposure evoked pulmonary fibrosis and epithelial-mesenchymal transition (EMT) in mice. Both in vivo and in vitro, BPDE exposure promoted nuclear translocation of Snail. Further experiments indicated that nuclear factor erythroid 2-related factor 2 (Nrf2) and p62 were upregulated in BPDE-exposed alveolar epithelial cells. Moreover, Nrf2 siRNA transfection evidently attenuated BPDE-induced p62 upregulation. Besides, p62 shRNA inhibited BPDE-incurred Snail nuclear translocation and EMT. Mechanically, BPDE facilitated physical interaction between p62 and Snail in the nucleus, then repressed Snail protein degradation by p62-dependent autophagy-lysosome pathway, and finally upregulated transcriptional activity of Snail. Additionally, aryl hydrocarbon receptor (AhR) was activated in BPDE-treated alveolar epithelial cells. Dual-luciferase assay indicated activating AhR could bind to Nrf2 gene promoter. Moreover, pretreatment with CH223191 or α-naphthoflavone (α-NF), AhR antagonists, inhibited BPDE-activated Nrf2-p62 signaling, and alleviated BPDE-induced EMT and pulmonary fibrosis in mice. Taken together, AhR-mediated Nrf2-p62 signaling contributes to BaP-induced EMT and pulmonary fibrosis.

Reduction of lymphocyte count at early stage elevates severity and death risk of COVID-19 patients: a hospital-based case-cohort study.

Introduction: Several reports have noted that severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) induced lymphopenia in coronavirus disease 2019 (COVID-19) patients. However, the clinical significance of lymphopenia remains unclear. The objective of this study was to analyze the association between lymphopenia at an early stage and the prognosis of COVID-19 patients. Material and methods: All 192 hospitalized patients with COVID-19 were enrolled. Demographic data and clinical characteristics were collected and patient's prognosis was followed up. Results: On admission, 84 (43.8%) patients suffered from lymphopenia among COVID-19 patients. The count and percentage of lymphocytes on admission were lower among patients over 70 years old than those of younger patients. Multivariate logistic regression revealed that older age was a risk factor of lymphopenia. Of interest, chest CT score, a key marker of lung injury, was increased among COVID-19 patients with lymphopenia. By contrast, PaCO2, SpO2 and oxygenation index, several respiratory function markers, were decreased in COVID-19 patients with lymphopenia. Moreover, total bilirubin (TBIL) and direct bilirubin (DBIL), two markers of hepatic injury, creatinine and urea nitrogen, two indices of renal function, and creatine kinase, AST and LDH, three myocardial enzymes, were elevated in COVID-19 patients with lymphopenia. Among 84 COVID-19 patients with lymphopenia, 32.1% died. The fatality rate was obviously higher in COVID-19 patients with lymphopenia. Conclusions: Older COVID-19 patients are more susceptible to lymphopenia. Multiple organ injuries were more serious in COVID-19 patients with lymphopenia. Lymphopenia at an early stage aggravates the severity and elevates the death risk of COVID-19 patients.

N-acetylcysteine alleviates pulmonary inflammatory response during benzo[a]pyrene-evoked acute lung injury.

Benzo[a]pyrene (BaP), a representative polycyclic aromatic hydrocarbon, exists widely in automobile emissions and polluted atmosphere. The current study aimed to describe pulmonary inflammation during BaP-induced acute lung injury (ALI). All mice except controls were intratracheally instilled with a single dose of BaP (90 µg per mouse). The alveolar structure was damaged, accompanied by numerous inflammatory cell infiltration around pulmonary interstitium and small airway. Airway wall area and mean linear intercept were reduced in BaP-exposed mouse lungs. By contrast, airway wall thickness and destructive index were elevated in BaP-exposed mouse lungs. Several inflammatory genes, such as Tnf-α, Il-1ß, Il-6, Mip-2, Kc, and Mcp-1, were upregulated in mouse lungs. Phosphorylated IκBα was elevated in BaP-exposed mouse lungs. Nuclear translocation of NF-κB p65 and p50 was accordingly observed in BaP-exposed mouse lungs. Several molecules of the MAPK pathway, including JNK, ERK1/2, and p38, were activated in mouse lungs. Of interest, pretreatment with N-acetylcysteine (NAC), an antioxidant, alleviated BaP-induced ALI. Moreover, NAC attenuated BaP-induced inflammatory cell infiltration in mouse lungs and inflammatory gene upregulation in A549 cells. In addition, NAC attenuated BaP-induced NF-κB activation in A549 cells and mouse lungs. These results suggest that NAC alleviates pulmonary inflammatory response during BaP-evoked ALI.

Reactive oxygen species-evoked endoplasmic reticulum stress mediates 1-nitropyrene-induced epithelial-mesenchymal transition and pulmonary fibrosis.

1-Nitropyrene (1-NP) is one component of atmospheric fine particles. Previous report revealed that acute 1-NP exposure induced respiratory inflammation. This study aimed to investigate whether chronic 1-NP exposure induces pulmonary fibrosis. Male C57BL6/J mice were intratracheally instilled to 1-NP (20 µg/mouse/week) for 6 weeks. Diffuse interstitial inflammation, a-smooth muscle actin (a-SMA)-positive cells, a marker of epithelial-mesenchymal transition (EMT), and an extensive collagen deposition, measured by Masson staining, were observed in 1-NP-exposed mouse lungs. Pulmonary function showed that lung dynamic compliance (Cydn-min) was reduced in 1-NP-exposed mice. Conversely, inspiratory resistance (Ri) and expiratory resistance (Re) were elevated in 1-NP-exposed mice. Mechanistically, cell migration and invasion were accelerated in 1-NP-exposed pulmonary epithelial cells. In addition, E-cadherin, an epithelial marker, was downregulated, and vimentin, a-SMA and N-cadherin, three mesenchymal markers, were upregulated in 1-NP-exposed pulmonary epithelial cells. Although TGF-ß wasn't altered, phosphorylated Smad2/3 were enhanced in 1-NP-exposed pulmonary epithelial cells. Moreover, reactive oxygen species (ROS) were increased and endoplasmic reticulum (ER) stress was activated in 1-NP-exposed pulmonary epithelial cells. N-Acetylcysteine (NAC), an antioxidant, attenuated 1-NP-evoked excess ROS, ER stress and EMT in pulmonary epithelial cells. Similarly, pretreatment with NAC alleviated 1-NP-caused pulmonary EMT and lung fibrosis in mice. These results demonstrate that ROS-evoked ER stress contributes, at least partially, to 1-NP-induced EMT and pulmonary fibrosis.

Liver Dysfunction and Its Association with the Risk of Death in COVID-19 Patients: A Prospective Cohort Study.

Background and Aims: Coronavirus disease 2019 (COVID-19) is a new respiratory infectious disease caused by severe acute respiratory syndrome coronavirus-2 (commonly known as SARS-CoV-2) with multiple organ injuries. The aim of this study was to analyze COVID-19-associated liver dysfunction (LD), its association with the risk of death and prognosis after discharge. Methods: Three-hundred and fifty-five COVID-19 patients were recruited. Clinical data were collected from electronic medical records. LD was evaluated and its prognosis was tracked. The association between LD and the risk of death was analyzed. Results: Of the 355 COVID-19 patients, 211 had mild disease, 88 had severe disease, and 51 had critically ill disease. On admission, 223 (62.8%) patients presented with hypoproteinemia, 151(42.5%) with cholestasis, and 101 (28.5%) with hepatocellular injury. As expected, LD was more common in critically ill patients. By multivariate logistic regression, male sex, older age and lymphopenia were three important independent risk factors predicting LD among COVID-19 patients. Risk of death analysis showed that the fatality rate was higher in patients with hypoproteinemia than in those without hypoproteinemia (relative risk=9.471, p<0.01). Moreover, the fatality rate was higher in patients with cholestasis than those without cholestasis (relative risk=2.182, p<0.05). Follow-up observation found that more than one hepatic functional index of two-third patients remained abnormal at 14 days after discharge. Conclusions: LD at early disease stage elevates the risk of death of COVID-19 patients. COVID-19-associated LD does not recover completely by 14 days after discharge.

Myocardial Injury at Early Stage and Its Association With the Risk of Death in COVID-19 Patients: A Hospital-Based Retrospective Cohort Study.

Background: There are growing evidence demonstrating that coronavirus disease 2019 (COVID-19) is companied by acute myocardial injury. However, the associations of SARS-CoV-2-induced myocardial injury with the risk of death and prognosis after discharge in COVID-19 patients are unclear. Methods: This prospective cohort study analyzed 355 COVID-19 patients from two hospitals in different regions. Clinical and demographic information were collected and prognosis was followed up. Results: Of 355 hospitalized patients with COVID-19, 213 were mild, 90 severe, and 52 critically ill patients. On admission, 59 (16.7%) patients were with myocardial injury. Myocardial injury was more popular in critically ill patients. Univariate and multivariate logistic regression revealed that male, older age and comorbidity with hypertension were three crucial independent risk factors predicting myocardial injury of COVID-19 patients. Among 59 COVID-19 patients with myocardial injury, 25 (42.4%) died on average 10.9 days after hospitalization. Mortality was increased among COVID-19 patients with myocardial injury (42.4 vs. 3.38%, RR = 12.542, P < 0.001). Follow-up study observed that 4.67% COVID-19 patients with myocardial injury were not fully recovered in 14 days after discharge. Conclusion: Myocardial injury at early stage elevates mortality of COVID-19 patients. Male elderly patients with hypertension are more vulnerable to myocardial injury. SARS-CoV-2-induced myocardial injury has not completely recovered in 14 days after discharge.