Unraveling the independent role of METTL3 in m6A modification and tumor progression in esophageal squamous cell carcinoma.

METTL3 and METTL14 are traditionally posited to assemble the m6A methyltransferase complex in a stoichiometric 1:1 ratio, modulating mRNA fate via m6A modifications. Nevertheless, recent investigations reveal inconsistent expression levels and prognostic significance of METTL3 and METTL14 across various tumor types, challenging their consistent functional engagement in neoplastic contexts. A pan-cancer analysis leveraging The Cancer Genome Atlas (TCGA) data has identified pronounced disparities in the expression patterns, functional roles, and correlations with tumor burden between METTL3 and METTL14, particularly in esophageal squamous cell carcinoma (ESCC). Knockdown experiments of METTL3 in EC109 cells markedly suppress cell proliferation both in vitro and in vivo, whereas METTL14 knockdown shows a comparatively muted effect on proliferation and does not significantly alter METTL3 protein levels. mRNA sequencing indicates that METTL3 singularly governs the expression of 1615 genes, with only 776 genes co-regulated with METTL14. Additionally, immunofluorescence co-localization studies suggest discrepancies in cellular localization between METTL3 and METTL14. High-performance liquid chromatography-mass spectrometry (HPLC-MS) analyses demonstrate that METTL3 uniquely associates with the Nop56p-linked pre-rRNA complex and mRNA splicing machinery, independent of METTL14. Preliminary bioinformatics and multi-omics investigations reveal that METTL3's autonomous role in modulating tumor cell proliferation and its involvement in mRNA splicing are potentially pivotal molecular mechanisms. Our study lays both experimental and theoretical groundwork for a deeper understanding of the m6A methyltransferase complex and the development of targeted tumor therapies focusing on METTL3.

Comprehensive appraisal of lung function in young COPD patients: a single center observational study.

PURPOSE: The present study aimed to investigate the clinical characteristics and lung function impairment in young people diagnosed with chronic obstructive pulmonary disease (COPD). PATIENTS AND METHODS: We retrospectively enrolled patients with COPD who underwent symptom assessment and comprehensive pulmonary function tests at the First Affiliated Hospital of Guangzhou Medical University between August 2017 and March 2022. The patients were categorized into two groups based on age: a young COPD group (aged 20-50 years) and an old COPD group (aged > 50 years). RESULTS: A total of 1282 patients with COPD were included in the study, with 76 young COPD patients and 1206 old COPD patients. Young COPD patients exhibited a higher likelihood of being asymptomatic, lower rates of smoking, and a lower smoking index compared to old COPD patients. Although young COPD patients had higher median post-bronchodilator forced expiratory volume in 1 s (post-BD FEV1) (1.4 vs.1.2 L, P = 0.019), diffusing capacity of the lung for carbon monoxide (DLCO) (7.2 vs. 4.6, P<0.001), and a lower median residual volume to total lung capacity ratio (RV/TLC) compared to their older counterparts, there were no differences observed in severity distribution by GOLD categories or the proportion of lung hyperinflation (RV/TLC%pred > 120%) between two groups. Surprisingly, the prevalence of reduced DLCO was found to be 71.1% in young COPD, although lower than in old COPD (85.2%). CONCLUSION: Young COPD showed fewer respiratory symptoms, yet displayed a similar severity distribution by GOLD categories. Furthermore, a majority of them demonstrated lung hyperinflation and reduced DLCO. These results underscore the importance of a comprehensive assessment of lung function in young COPD patients.

Mechanism of intestinal microbiota disturbance promoting the occurrence and development of esophageal squamous cell carcinoma--based on microbiomics and metabolomics.

Esophageal squamous cell carcinoma (ESCC) is a high-risk malignant tumor that has been reported in China. Some studies indicate that gut microbiota disorders can affect the occurrence and development of ESCC, but the underlying mechanism remains unclear. In this study, we aimed to explore the possible underlying mechanisms using microbiomics and metabolomics. Fifty ESCC patients and fifty healthy controls were selected as the study subjects according to sex and age, and fecal samples were collected. 16S rDNA sequencing and LC‒MS were used for microbiomics and nontargeted metabolomics analyses. We found significant differences in the composition of the gut microbiota and metabolites between the ESCC patients and control individuals (P < 0.05). ESCC patients exhibited increased abundances of Fusobacteriaceae and Lactobacillus, increased levels of GibberellinA34 and decreased levels of 12-hydroxydodecanoic acid; these metabolites could be diagnostic and predictive markers of ESCC. An increase in the abundance of Enterobacteriaceae and Lactobacillus significantly reduced the content of L-aspartate and pantothenic acid, which may be involved in the occurrence and development of ESCC by downregulating the expression of proteins in the pantothenate and coenzyme A biosynthesis pathways. An imbalance in the intestinal flora may decrease the number of eosinophils in peripheral blood, resulting in the activation of an inflammatory response and immune dysfunction, leading to ESCC deterioration. We hypothesize that this imbalance in the gut microbiota can cause an imbalance in intestinal metabolites, which can activate carcinogenic metabolic pathways, affect inflammation and immune function, and play a role in the occurrence and development of ESCC.

Hospitalization, case fatality, comorbidities, and isolated pathogens of adult inpatients with pneumonia from 2013 to 2022: a real-world study in Guangzhou, China.

BACKGROUND: In the context of increasing population aging, ongoing drug-resistant pathogens and the COVID-19 epidemic, the changes in the epidemiological and clinical characteristics of patients with pneumonia remain unclear. This study aimed to assess the trends in hospitalization, case fatality, comorbidities, and isolated pathogens of pneumonia-related adult inpatients in Guangzhou during the last decade. METHODS: We retrospectively enrolled hospitalized adults who had doctor-diagnosed pneumonia in the First Affiliated Hospital of Guangzhou Medical University from January 1, 2013 to December 31, 2022. A natural language processing system was applied to automatically extract the clinical data from electronic health records. We evaluated the proportion of pneumonia-related hospitalizations in total hospitalizations, pneumonia-related in-hospital case fatality, comorbidities, and species of isolated pathogens during the last decade. Binary logistic regression analysis was used to assess predictors for patients with prolonged length of stay (LOS). RESULTS: A total of 38,870 cases were finally included in this study, with 70% males, median age of 64 (53, 73) years and median LOS of 7.9 (5.1, 12.8) days. Although the number of pneumonia-related hospitalizations showed an upward trend, the proportion of pneumonia-related hospitalizations decreased from 199.6 per 1000 inpatients in 2013 to 123.4 per 1000 in 2021, and the case fatality decreased from 50.2 per 1000 in 2013 to 23.9 per 1000 in 2022 (all P < 0.05). The most common comorbidities were chronic obstructive pulmonary disease, lung malignancy, cardiovascular diseases and diabetes. The most common pathogens were Pseudomonas aeruginosa, Candida albicans, Acinetobacter baumannii, Stenotrophomonas maltophilia, Klebsiella pneumoniae, and Staphylococcus aureus. Glucocorticoid use during hospitalization (Odd Ratio [OR] = 1.86, 95% Confidence Interval (CI): 1.14-3.06), immunosuppressant use during hospitalization (OR = 1.99, 1.14-3.46), ICU admission (OR = 16.23, 95%CI: 11.25-23.83), receiving mechanical ventilation (OR = 3.58, 95%CI: 2.60-4.97), presence of other underlying diseases (OR = 1.54, 95%CI: 1.15-2.06), and elevated procalcitonin (OR = 1.61, 95%CI: 1.19-2.19) were identified as independent predictors for prolonged LOS. CONCLUSION: The proportion of pneumonia-related hospitalizations and the in-hospital case fatality showed downward trends during the last decade. Pneumonia inpatients were often complicated by chronic underlying diseases and isolated with gram-negative bacteria. ICU admission was a significant predictor for prolonged LOS in pneumonia inpatients.

Supervised training models with or without manual lesion delineation outperform clinicians in distinguishing pulmonary cryptococcosis from lung adenocarcinoma on chest CT.

BACKGROUND: The role of artificial intelligence (AI) in the discrimination between pulmonary cryptococcosis (PC) and lung adenocarcinoma (LA) warrants further research. OBJECTIVES: To compare the performances of AI models with clinicians in distinguishing PC from LA on chest CT. METHODS: Patients diagnosed with confirmed PC or LA were retrospectively recruited from three tertiary hospitals in Guangzhou. A deep learning framework was employed to develop two models: an undelineated supervised training (UST) model utilising original CT images, and a delineated supervised training (DST) model utilising CT images with manual lesion annotations provided by physicians. A subset of 20 cases was randomly selected from the entire dataset and reviewed by clinicians through a network questionnaire. The sensitivity, specificity and accuracy of the models and the clinicians were calculated. RESULTS: A total of 395 PC cases and 249 LA cases were included in the final analysis. The internal validation results for the UST model showed a sensitivity of 85.3%, specificity of 81.0%, accuracy of 83.6% and an area under the curve (AUC) of 0.93. Similarly, the DST model exhibited a sensitivity of 88.2%, specificity of 88.1%, accuracy of 88.2% and an AUC of 0.94. The external validation of the two models yielded AUC values of 0.74 and 0.77, respectively. The average sensitivity, specificity and accuracy of 102 clinicians were determined to be 63.1%, 53.7% and 59.3%, respectively. CONCLUSIONS: Both models outperformed the clinicians in distinguishing between PC and LA on chest CT, with the UST model exhibiting comparable performance to the DST model.

Identification of KIFC1 as an independent prognostic marker in renal clear cell carcinoma correlates with tumor proliferation and immune infiltration.

Renal clear cell carcinoma (ccRCC) is the world's most common form of cancer. Up to a third will develop metastases; the 5-year survival rate of the patients was only 14%. Practical prognostic markers remain to be discovered. Kinesin-like protein (KIFC1), a critical factor in maintaining the stability of the microtubule system, has significant prognostic value in some tumors. We analyzed the prognostic value, associated signaling pathways, and regulatory mechanisms of KIFC1 in ccRCC through bioinformatics and proteomics. Concretely, both mRNA and protein expression levels of KIFC1 were dramatically upregulated. KIFC1 is an independent prognostic factor for ccRCC. The expression of KIFC1 showed a significant positive correlation (Spearman coefficient > 0.7) with tumor proliferation-related pathways (tumor proliferation, G2/M checkpoint, and DNA replication) and tumor inflammation. Further, intratumoral immune cell analysis revealed that high expression of KIFC1 predicted more infiltration of CD8 + T and CD4 + T cells (p < 0.001). However, there was a significant positive relationship between CD8 + T cells and numerous immune checkpoint genes. CD8 + T cells in tumors from the KIFC1 high expression group were at the dysregulated state. High expression of KIFC1 may predict a poor immunotherapy outcome. By proteomics, we analyzed proteins interacting with KIFC1; spliceosome proteins had the most significant enrichment, indicating the new directions for KIFC1 investigation. In conclusion, our study identified KIFC1 as an independent prognostic factor in renal clear cell carcinoma, and the associated processes involved tumor proliferation and immune infiltration. KIFC1 had a close relationship with spliceosome proteins; it may be a new research direction.

Prevalence, risk factors, and mortality of COPD in young people in the USA: results from a population-based retrospective cohort.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) has been considered a disease of the elderly, but it could also occur in young people aged 20-50 years. However, the characteristics and prognosis of COPD in such young people remain unclear. METHODS: Our retrospective cohort study was based on the National Health and Nutrition Examination Survey (NHANES). Participants who 20-50 years old at baseline and completed the pulmonary function test were enrolled in our study cohort. These participants were followed up to 31 December 2019. The sample weight and Taylor Linearization Procedures were adapted to make representative estimations of prevalence and baseline characteristics. The weighted logistic regression model was used to assess the risk factors. The propensity score method and Cox proportional hazard models were applied to calculate the risk of mortality. RESULTS: The weighted prevalence of COPD in young people in the USA was 1.64% and it increased with age, with a higher prevalence in males than females (2.59% vs 0.72%, p<0.001). The proportion of Global Initiative for COPD 1-2 was 96.7%. Males (OR=4.56, 95% CI: 2.74 to 7.61), non-Hispanic black (OR=2.77; 95% CI: 1.14 to 6.75), non-Hispanic white (OR=4.93; 95% CI: 2.16 to 11.28) and smoking (current smoking, OR=2.36; 95% CI: 1.40 to 3.98; ever smoking, OR=1.92; 95% CI: 1.05 to 3.51; passive smoking, OR=2.12; 95% CI: 1.41 to 3.20) were shown to be independent risk factors for COPD in young people. Compared with those matched by sex, age and race, the young people with COPD had a higher risk of all-cause death (HR=3.314, p<0.001). CONCLUSION: COPD in young people has a low prevalence in the USA and its independent risk factors included male, race (non-Hispanic black and non-Hispanic white) and smoking. Young COPD has a higher risk of all-cause mortality than the matched non-COPD.

Global, regional, and national burden of asthma and its attributable risk factors from 1990 to 2019: a systematic analysis for the Global Burden of Disease Study 2019.

BACKGROUND: The burden of asthma in terms of premature death or reduced quality of life remains a huge issue. It is of great importance to evaluate asthma burden geographically and time trends from 1990 to 2019 and to assess the contributions of age, period, and cohort effects at global level. METHODS: Asthma prevalence, deaths, and disability adjusted life years (DALYs) as well as risk-attributable burden were collected from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 database and were compared by age and sex. The Smoothing Splines models were used to estimate the relationship between asthma DALYs and the sociodemographic index (SDI). The Age-Period-Cohort model was used to determine effects of ages, periods, and birth cohorts on disease rates. RESULTS: Between 1990 and 2019, the declines were 24.05% (95% uncertainty interval [UI] - 27.24 to - 20.82) in age-standardized asthma prevalence, 51.3% (- 59.08 to - 43.71) in mortality, and 42.55% (- 48.48 to - 36.61) in DALYs rate. However, the burden of asthma continued to rise, with an estimated 262.41 million prevalent cases globally (95% UI 224.05 to 309.45). Asthma caused greater DALYs in females than in males among people aged 20 years and older. The lowest age-standardized DALYs rate was observed at a SDI of approximately 0.70. The Longitudinal age curves showed an approximate W-shaped pattern for asthma prevalence and a likely J-shaped pattern for asthma mortality. The period effect on prevalence and mortality of asthma decreased from 1990 to 2019. Compared with the 1955-1959 birth cohort, the prevalence relative risk (RR) of asthma was highest in the 1905-1909 birth cohort, whereas the mortality RR continued to decline. At the global level, the percentages of high body-mass index, occupational asthmagens, and smoking contributing to DALYs due to asthma were 16.94%, 8.82%, and 9.87%, respectively. CONCLUSIONS: Although the age-standardized rates of asthma burden declined in the past 30 years, the overall burden of asthma remains severe. High body mass index becomes the most important risk factor for DALYs due to asthma at the global level.

Association of NAD+ levels with metabolic disease in a community-based study.

Background: Nicotinamide adenine dinucleotide (NAD+) is a coenzyme and plays a crucial role in several metabolic processes. This study explored the association of nicotinamide adenine dinucleotide (NAD+) levels with metabolic disease (MD) in adults. Methods: In this cross-sectional study, all data were collected from the Jidong community. MD was defined as the presence of one or more of the following disease components: hypertension, dyslipidemia, diabetes, hyperuricemia, obesity, and non-alcoholic fatty liver disease (NAFLD). The MD components were categorized into three groups: those with one component, those with two components, and those with three to six components. The whole blood NAD+ level was measured using a cycling assay and LC-MS/MS analysis. The participants were divided into four groups based on their NAD+ level quartiles. Multivariable logistic regression was used to evaluate the association of the whole blood NAD+ levels with MD. Results: Of the 1,394 eligible participants, the average age was 43.2 years, and 74.3% had MD. In the top quartile of NAD+, the prevalence of MD and each of its components (hypertension, hyperlipidemia, diabetes, hyperuricemia, obesity, and NAFLD) were 87.9% 35.2%, 62.3%, 8.7%, 36.9%, 21.0%, and 60.5%, respectively. As compared with the lowest NAD+ quartile (≤29.4 µmol/L), the adjusted odds ratios and 95% confidence interval of the highest quartile were 3.01 (1.87-4.87) for MD, 2.48 (1.44-4.29) for 1 MD component, 2.74 (1.45-5.17) for 2 MD components, and 4.30 (2.32-7.98) for 3-6 MD components. The risk of MD began to increase at NAD+ levels of 31.0 µmol/L, as revealed by the gradient associations of NAD+ levels with MD. There was no significant interaction between age, sex, drinking, smoking, and NAD+ for MD (p for interaction ≥0.10). Conclusions: Increased NAD+ was significantly associated with MD, as well as its individual components. Our findings provide new evidence for the relationship between blood NAD+ levels and MD.

The m6A reader YTHDC1 regulates muscle stem cell proliferation via PI4K-Akt-mTOR signalling.

Muscle stem cells are required for the homeostasis and regeneration of mammalian skeletal muscles. It has been reported that RNA N6-methyladenosine (m6A) modifications play a pivotal role in muscle development and regeneration. Nevertheless, we know little about which m6A reader regulates mammalian muscle stem cells. Here, we discovered that the m6A reader Ythdc1 is indispensable for mouse skeletal muscle regeneration and proliferation of muscle stem cells. In the absence of Ythdc1, Muscle stem cells in adult mice are unable to exit from quiescence. Mechanistically, Ythdc1 binds to m6A-modified Pi4k2a and Pi4kb mRNAs to regulate their alternative splicing and thus PI4K-Akt-mTOR signalling. Ythdc1-null muscle stem cells show a deficiency in phosphatidylinositol (PI) 3,4,5-trisphosphate, phospho-Akt and phospho-S6, which correlates with a failure in exit from quiescence. Our findings connect dynamic RNA methylation to the regulation of PI4K-Akt-mTOR signalling during stem cell proliferation and adult tissue regeneration.

Benzo(a)pyrene-induced mitochondrial respiration and glycolysis disturbance in human neuroblastoma cells.

Mammalian cells generate ATP through mitochondrial respiration and glycolysis. Mitochondria not only play a key role in cell energy metabolism but also in cell cycle regulation. As a neurotoxic pollutant, benzo(a)pyrene (BaP) can trigger neuronal oxidative damage and apoptosis. However, the features of BaP-induced energy metabolism disturbance in SH-SY5Y cells has rarely been addressed. This study aimed to measure oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) as indications of respiratory activities and glycolytic. SH-SY5Y cells were treated with BaP to establish a cytotoxicity model, and butylated hydroxy anisole (BHA) was used to alleviate the damages induced by BaP. Using the Seahorse Extracellular Flux analyzer (XFp), we found that BaP significantly reduced basal respiration, ATP-linked OCR in SH-SY5Y cells with dose- and time-dependent. BHA supplementation recovered the mitochondrial respiration, synchronously attenuated intracellular ROS generation and lipid peroxidation, and simultaneously reversed the abnormal changes in antioxidant biomarkers, then rescued BaP-induced cell apoptosis. But long-term exposure to BaP or exposure to a high dosage of BaP could decrease OCR associated with maximal respiratory, spare capacity, and glycolysis metabolism. At the same time, the damage to cells is also more severe with the rate of apoptosis and mitochondrial membrane potential (ΔΨm) loss rising sharply, which were not entirely reversed by BHA. This study provides energy metabolism-related, indicative biomarkers of cytotoxicity induced by BaP, which might provide information for early prevention and intervention.

The role of reactive astrocytes in neurotoxicity induced by ultrafine particulate matter.

Epidemiological studies have shown that ambient fine particulate matter (PM) can cause various neurodegenerative diseases, including Alzheimer's disease. Reactive astrocytes are strongly induced by ambient fine PM, although their role is poorly understood. Herein, we show that A1 reactive astrocytes (A1s) were induced by neuroinflammatory microglia activated by PM with an aerodynamic diameter ≤ 0.2 µm (PM0.2). The activated-microglia induced A1s by secreting interleukin-1α, tumor necrosis factor-α, and complement 1q, and these cytokines acting together were necessary and sufficient to induce A1s. PM0.2-induced A1s could promote synaptic damage in neurons by secreting complement 3 (C3). SB 290157, a highly selective C3aR nonpeptide antagonist, partially ameliorated glial conditioned medium-induced synaptic injury. In vitro synaptic damage was partially prevented when A1 formation was blocked by minocycline. Finally, this study showed that N-acetyl-L-cysteine ameliorated PM0.2-induced neural damage independent of A1 differentiation. Collectively, these findings explain why central nervous system neurons suffer synaptic damage and neuroinflammation after PM0.2 exposure and suggest that this exposure induces A1s to contribute to synaptic damage of neurons. This study indicates a potential approach for developing improved treatment of these diseases induced by particulate exposure. SYNOPSIS: PM0.2-activated neuroinflammatory microglia induced A1 reactive astrocytes (A1s) by secreting IL-1α, TNF-α, and C1q. PM0.2-induced A1s could promote synaptic damage of neuron by secreting complement 3.

Nano-Calcium Carbonate Affect the Respiratory and Function Through Inducing Oxidative Stress: A Cross-sectional Study Among Occupational Exposure of Workers and a Further Research for Underlying Mechanisms.

OBJECTIVE: The aim of the study is to investigate whether nano-calcium carbonate (nano-CaCO 3 ) occupational exposure could induce adverse health effects in workers. METHODS: A cross-sectional study was conducted in a nano-CaCO 3 manufacturing plant in China. Then, we have studied the dynamic distribution of nano-CaCO 3 in nude mice and examined the oxidative damage biomarkers of subchronic administrated nano-CaCO 3 on Sprague-Dawley rats. RESULTS: The forced vital capacity (%) and the ratio of FEV1 to FVC is the rate of one second of workers were significantly decreased than unexposed individuals. Dynamic imaging in mice of fluorescence labeled nano-CaCO 3 showed relatively high uptake and slow washout in lung. Similar to population data, the decline in serum glutathione level and elevation in serum MDA were observed in nano-CaCO 3 -infected Sprague-Dawley rats. CONCLUSIONS: We found that nano-CaCO 3 exposure may result in the poor pulmonary function in workers and lead to the changes of oxidative stress indexes.

Organic extracts in PM2.5 are the major triggers to induce ferroptosis in SH-SY5Y cells.

As a major air pollutant, PM2.5 can induce apoptosis of nerve cells, causing impairment of the learning and memory capabilities of humans and animals. Ferroptosis is a newly discovered way of programmed cell death. It is unclear whether the neurotoxicity induced by PM2.5 is related to the ferroptosis of nerve cells. In this study, we observed the changes in ferroptosis hallmarks of SH-SY5Y cells after exposure to various doses (40, 80, and 160 µg/mL PM2.5) for 24 h, exposure to 40 µg/mL PM2.5 for various times (24, 48, and 72 h), as well as exposure to various components (Po, organic extracts; Pw, water-soluble extracts; Pc, carbon core component). The results showed that PM2.5 reduced the cell viability, the content of GSH, and the activity of GSH-PX and SOD in SH-SY5Y cells with exposure dose and duration increasing. On the other hand, PM2.5 increased the content of iron, MDA, and the level of lipid ROS in SH-SY5Y cells with exposure dose and duration increasing. Additionally, PM2.5 reduced the expression levels of HO-1, NRF2, SLC7A11, and GPX4. The ferroptosis inhibitors Fer-1 and DFO significantly increase the cells viabilities and significantly reversed the changes of other above ferroptosis hallmarks. We also observed the different effects on ferroptosis hallmarks in the SH-SY5Y cells exposed to PM2.5 (160 µg/mL) and its various components (organic extracts, water-soluble extracts, and carbon core) for 24 h. We found that only the organic extracts shared similar results with PM2.5 (160 µg/mL). This study demonstrated that PM2.5 induced ferroptosis of SH-SY5Y cells, and organic extracts might be the primary component that caused ferroptosis.

Benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide induces ferroptosis in neuroblastoma cells through redox imbalance.

As a widespread environmental pollutant, benzo(a)pyrene-7,8-diol-9,10-epoxide (BPDE)-induced neurotoxicity has received increasing attention. Studies have shown that BPDE-induced neurodegeneration is due partly to neuronal apoptosis. Unlike apoptosis, ferroptosis is a non-apoptotic form of programmed cell death, but its specific role in the neurotoxicity of BPDE remains unclear. In this work, we investigated the ferroptosis in BPDE-induced cell death in human neuroblastoma cell line SH-SY5Y using a specific pharmacological inhibitor. Lipid peroxides, malondialdehyde production, glutathione / glutathione peroxidase activity, superoxide dismutase activity, and iron content were evaluated. Consistent with previous studies, our data showed that 0.5 µM BPDE poisoning for 24 hr could induce cell apoptosis and that cell survival could be improved by using apoptosis inhibitors. But with prolonged exposure time (72 hr) or increased exposure dose (1.0 µM), we have elucidated and validated that BPDE triggered ferroptosis in human SH-SY5Y cells. We also revealed that suppression of ferroptosis by specific inhibitors, ferrostatin-1 and deferoxamine, significantly rescued the phenotypes of ferroptosis induced by BPDE. BPDE downregulated Nrf2 and its target genes related to redox regulation, GPX4 and SLC7A11, but upregulated HO-1. Our results first demonstrated that BPDE caused cytotoxic effects on cell death via apoptosis and ferroptosis. Most notably, long-term environmental exposure to BPDE becomes a concern due to ferroptosis. Redox imbalance is controlled by the Nrf2, SLC7A11, and HO-1, through which lipid peroxides and ferrous ion accumulation cause ferroptosis after BPDE treatment. These findings highlight that targeting ferroptosis could serve as an effective protective strategy for neurotoxicity of BPDE.

Energy metabolism disorders and oxidative stress in the SH-SY5Y cells following PM2.5 air pollution exposure.

Studies have shown that PM2.5 exposure can induce neuronal apoptosis and neurobehavioral changes in animal experiments due partly to the mitochondria-mediated oxidative damage. How does it affect the mitochondrial energy metabolism as well as the neuronal damage, however, remain unclear. This study aimed to investigate the molecular processes of energy metabolism and oxidative damage induced by ambient PM2.5 exposure in SH-SY5Y cells. SH-SY5Y cells were treated with PM2.5 to establish a cytotoxicity model. A Seahorse Extracellular Flux Analyzer (XFp) was performed to evaluate the cellular mitochondrial respiratory and glycolysis after exposure to PM2.5. The dose- and time-dependent effects of PM2.5 on oxidative damage and apoptosis were analyzed. To further explore the relationship among oxidative damage, energy metabolism and apoptosis, SH-SY5Y cells were co-cultured with BHA and PM2.5 for 24 h. The results demonstrated that the basic respiration and ATP production, the typical index of mitochondrial respiration as well as glycolysis, significantly reduced in SH-SY5Y cells with dose and time dependent. At the same time, the PM2.5 could significantly decrease the cell viability and Mn-SOD activity, and increase the ROS levels and apoptosis rate as the escalation of dose and the extension of time. Importantly, the application of BHA could synchronously recover the PM2.5 induced cell energy metabolism disorder, oxidative damage, and apoptosis. It seems that the abnormal cellular energy metabolism may be caused by oxidative damage following fine particles exposure, and further led to apoptosis.

Association of Human Whole Blood NAD+ Contents With Aging.

Background: NAD+, nicotinamide adenine dinucleotide, is mostly described to associate with the aging process. We aimed to investigate the association between human whole blood NAD+ contents and aging in a relative large-scale community-based population and further to address the gender impact on this association. Methods: We recruited 1,518 participants aged over 18 years old and free of cardiovascular and any type of cancer from the Jidong community from 2019 to 2020. Whole blood NAD+ level was measured by cycling assay and LC-mass spectroscopy assay. The chronological age and clinical data were collected using standard questionnaires. The participants were divided into five groups according to their chronological age. General liner regression model was performed to analyze the association between NAD+ contents and aging. In addition, we also conducted subgroup analysis by gender. Results: The mean age of included 1,518 participants was 43.0 years, and 52.6% of them were men. The average levels of whole blood NAD+ of total participants was 33.0 ± 5.5 µmol/L. The whole blood NAD+ contents in men were significantly higher than that in women (34.5 vs. 31.3 µmol/L). There was significant difference in the meat diet among NAD+ quartile groups (p = 0.01). We observed a decline trend of NAD+ contents with aging before 50 years in total participants with significant level in 40-49 years old group (ß coefficients with 95% confidence interval (95% CI): -1.12 (-2.18, -0.06)), while this trend disappeared after the 50 years. In addition, this association was significantly altered by gender (p for interaction = 0.003). In men, as compared with ≤29 years group, adjusted ß coefficient decreased with aging but was only significant in the ≥60 year group (ß,-2.16; 95% CI, -4.16 to -0.15). In females, the level of whole blood NAD+ did not significantly differ among five age groups and without the trend as males. Conclusions: Association of whole blood NAD+ contents with aging significantly differed in males and females. The loss of blood NAD+ with aging only was observed in males, especially in the male middle-aged population. It is crucial to consider the gender difference in further NAD+ related studies in the future.

MUC5B regulates goblet cell differentiation and reduces inflammation in a murine COPD model.

BACKGROUND: Airway mucus hypersecretion is one of the important pathological features of chronic obstructive pulmonary disease (COPD). MUC5B is the main mucin expressed in the airways of COPD patients and has been indicated to play an important role in airway defense. However, the specific biological function of MUC5B in COPD and the possible mechanism are not clear. METHODS: We established a COPD model with 24-week-old MUC5B-/- mice exposed to cigarette smoke and tested our hypothesis through lung function tests, HE and PAS staining, immunohistochemistry (IHC), western blot, q-PCR and ELISA. RESULTS: Compared with MUC5B+/+ mice, MUC5B-/- mice had worse general condition and lung function, increased inflammatory infiltration, reduced goblet cell differentiation as indicated by decreased PAS staining (PAS grade: 1.8 ± 0.24 vs. 0.6 ± 0.16), reduced MUC5AC expression (ELISA: 0.30 ± 0.01 vs. 0.17 ± 0.01 mg/ml, q-PCR: 9.4 ± 1.7 vs. 4.1 ± 0.1 fold, IHC score: 3.1 ± 0.9 vs. 1.6 ± 0.7), increased macrophage secretion of inflammatory factors (TNF-α and IL-6) and expression of downstream pathway factors (ERK1/2 and NF-κB), decreased expression of SPDEF and STAT6, and increased expression of FOXA2. CONCLUSION: The protective effect of MUC5B in the development of COPD was mediated by the promotion of goblet cell differentiation and the inhibition of inflammation. The role of MUC5B in regulating inflammation was related to macrophage function, and goblet cell differentiation was promoted by the induced expression of STAT6 and SPDEF. This study describes a mechanism of mucus hypersecretion and identifies MUC5B as a new target for the treatment of mucus hypersecretion.

A ratiometric fluorescent nanoprobe for signal amplification monitoring of intracellular telomerase activity.

Telomerase is considered a valuable diagnostic and prognostic cancer biomarker. Accurate and reliable detection of telomerase activity is of great value in clinical diagnosis, screening of inhibitors, and therapeutics. Here, we developed a novel amplified fluorescence resonance energy transfer (FRET) nanoprobe for highly sensitive and reliable monitoring of intracellular telomerase activity. The nanoprobe (QDSA@DNA) was composed of a streptavidin-modified quantum dot (QDSA) which was functionalized with a telomerase primer sequence (TP) and Cy5-tagged signal switching sequence (SS) through biotin-streptavidin interaction. When the nanoprobe was assembled, the Cy5 was in close proximity to the QDSA, resulting in high FRET efficiency from the QDSA to Cy5. In the presence of telomerase, the TP could be extended to produce telomeric repeat units, which was complementary to the loop of SS. Thus, the SS could hybridize with elongated sequences to form a rigid double-stranded structure, which forced the Cy5 away from the surface of the QDSA, causing low FRET efficiency. Furthermore, due to the production of multiple repeat units by telomerase, multiple hairpin structures could be opened, yielding significant fluorescence ratio (FQDsa/FCy5) enhancement for sensing of telomerase activity. In this way, the combination of a FRET and target-assisted strategy in a nanoprobe improved the detection accuracy and amplified the detection signal, respectively. The QDSA@DNA nanoprobe also showed high selectivity, excellent nuclease stability, and good biocompatibility. More importantly, this nanoprobe was found to be an excellent platform for efficient monitoring of intracellular telomerase activity, providing a potential platform in tumor diagnosis and screening of telomerase-related inhibitors.

Clinical analysis of the "small plateau" sign on the flow-volume curve followed by deep learning automated recognition.

BACKGROUND: Small plateau (SP) on the flow-volume curve was found in parts of patients with suspected asthma or upper airway abnormalities, but it lacks clear scientific proof. Therefore, we aimed to characterize its clinical features. METHODS: We involved patients by reviewing the bronchoprovocation test (BPT) and bronchodilator test (BDT) completed between October 2017 and October 2020 to assess the characteristics of the sign. Patients who underwent laryngoscopy were assigned to perform spirometry to analyze the relationship of the sign and upper airway abnormalities. SP-Network was developed to recognition of the sign using flow-volume curves. RESULTS: Of 13,661 BPTs and 8,168 BDTs completed, we labeled 2,123 (15.5%) and 219 (2.7%) patients with the sign, respectively. Among them, there were 1,782 (83.9%) with the negative-BPT and 194 (88.6%) with the negative-BDT. Patients with SP sign had higher median FVC and FEV1% predicted (both P < .0001). Of 48 patients (16 with and 32 without the sign) who performed laryngoscopy and spirometry, the rate of laryngoscopy-diagnosis upper airway abnormalities in patients with the sign (63%) was higher than those without the sign (31%) (P = 0.038). SP-Network achieved an accuracy of 95.2% in the task of automatic recognition of the sign. CONCLUSIONS: SP sign is featured on the flow-volume curve and recognized by the SP-Network model. Patients with the sign are less likely to have airway hyperresponsiveness, automatic visualizing of this sign is helpful for primary care centers where BPT cannot available.