Gene expression profiles and bioinformatics analysis of human umbilical vein endothelial cells exposed to PM2.5

Wildland fire, air pollution and cardiovascular health: is it time to focus on the microvasculature as a risk assessment tool?

Climate change favors weather conditions conducive to wildland fires. The intensity and frequency of forest fires are increasing, and fire seasons are lengthening. Exposure of human populations to smoke emitted by these fires increases, thereby contributing to airborne pollution through the emission of gas and particulate matter (PM). The adverse health outcomes associated with wildland fire exposure represent an important burden on the economies and health systems of societies. Even though cardiovascular diseases (CVDs) are the main of cause of the global burden of diseases attributable to PM exposure, it remains difficult to show reliable associations between exposure to wildland fire smoke and cardiovascular disease risk in population-based studies. Optimal health requires a resilient and adaptable network of small blood vessels, namely, the microvasculature. Often alterations of this microvasculature precede the occurrence of adverse health outcomes, including CVD. Biomarkers of microvascular health could then represent possible markers for the early detection of poor cardiovascular outcomes. This review aims to synthesize the current literature to gauge whether assessing the microvasculature can better estimate the cardiovascular impact of wildland fires.

Effects of ambient particulate exposure on blood lipid levels in hypertension inpatients

Background

With modernization development, multiple studies of atmospheric particulate matter exposure conducted in China have confirmed adverse cardiovascular health effects. However, there are few studies on the effect of particulate matter on blood lipid levels in patients with cardiovascular disease, especially in southern China. The purpose of this study was to investigate the association between short- and long-term exposure to ambient particulate matter and the levels of blood lipid markers in hypertension inpatients in Ganzhou, China.

Methods

Data on admission lipid index testing for hypertension inpatients which were divided into those with and without arteriosclerosis disease were extracted from the hospital's big data center from January 1, 2016 to December 31, 2020, and air pollution and meteorology data were acquired from the China urban air quality real time release platform from January 1, 2015 to December 31, 2020 and climatic data center from January 1, 2016 to December 31, 2020, with data integrated according to patient admission dates. A semi-parametric generalized additive model (GAM) was established to calculate the association between ambient particulate matter and blood lipid markers in hypertension inpatients with different exposure time in 1 year.

Results

Long-term exposure to particulate matter was associated with increased Lp(a) in three kinds of people, and with increased TC and decreased HDL-C in total hypertension and hypertension with arteriosclerosis. But particulate matter was associated with increased HDL-C for hypertension inpatients without arteriosclerosis, at the time of exposure in the present study. It is speculated that hypertension inpatients without arteriosclerosis has better statement than hypertension inpatients with arteriosclerosis on human lipid metabolism.

Conclusion

Long-term exposure to ambient particulate matter is associated with adverse lipid profile changes in hypertension inpatients, especially those with arteriosclerosis. Ambient particulate matter may increase the risk of arteriosclerotic events in hypertensive patients.

The pathophysiological and molecular mechanisms of atmospheric PM2.5 affecting cardiovascular health: A review

BACKGROUND

Exposure to ambient fine particulate matter (PM2.5, with aerodynamic diameter less than 2.5 µm) is a leading environmental risk factor for global cardiovascular health concern.

OBJECTIVE

To provide a roadmap for those new to this field, we reviewed the new insights into the pathophysiological and cellular/molecular mechanisms of PM2.5 responsible for cardiovascular health.

MAIN FINDINGS

PM2.5 is able to disrupt multiple physiological barriers integrity and translocate into the systemic circulation and get access to a range of secondary target organs. An ever-growing body of epidemiological and controlled exposure studies has evidenced a causal relationship between PM2.5 exposure and cardiovascular morbidity and mortality. A variety of cellular and molecular biology mechanisms responsible for the detrimental cardiovascular outcomes attributable to PM2.5 exposure have been described, including metabolic activation, oxidative stress, genotoxicity, inflammation, dysregulation of Ca2+ signaling, disturbance of autophagy, and induction of apoptosis, by which PM2.5 exposure impacts the functions and fates of multiple target cells in cardiovascular system or related organs and further alters a series of pathophysiological processes, such as cardiac autonomic nervous system imbalance, increasing blood pressure, metabolic disorder, accelerated atherosclerosis and plaque vulnerability, platelet aggregation and thrombosis, and disruption in cardiac structure and function, ultimately leading to cardiovascular events and death. Therein, oxidative stress and inflammation were suggested to play pivotal roles in those pathophysiological processes.

CONCLUSION

Those biology mechanisms have deepen insights into the etiology, course, prevention and treatment of this public health concern, although the underlying mechanisms have not yet been entirely clarified.

Gene expression in human umbilical vein endothelial cells exposed to fine particulate matter: RNA sequencing analysis

Exposure to airborne particulate matter (PM2.5) is associated with cardiovascular diseases. In order to investigate the molecular mechanisms of air pollution-induced CVDs toxicity, human umbilical vein endothelial cells (HUVECs) were exposed to PM2.5 collected from January, 2016 winter in Beijing, China. We performed RNA sequencing to elucidate key molecular mechanism of PM 2.5-mediated toxicity in HUVECs. A total of 1753 genes, 864 up-regulated and 889 down-regulated, were observed to be differentially expressed genes (DEGs). Among these, genes involved in metabolic response, oxidative stress, inflammatory response, and vascular dysfunction were significantly differentially expressed (log2 FC > 4). The results were validated by quantitative real-time PCR (qPCR) and Western blot for CYP1B1, HMOX1, IL8, and GJA4. Pathway analysis revealed that DEGs were involved in the biological processes related to metabolism, inflammation, and host defense against environmental insults. This research is providing a further understanding of the mechanisms underlying PM2.5-induced cardiovascular diseases (CVDs).

Molecular mechanism of Pulmonary diseases caused by exposure to urban PM2.5 in Chengdu-Chongqing Economic Circle, China

Chengdu-Chongqing Economic Circle (CD-CQ Economic Circle) is one of China's four major economic circles and five major urban agglomerations located in Southwest China's Sichuan Basin. The CD-CQ Economic Circle, with its strong economic development and dense population, suffers from severe PM_2.5 pollution, which is known to cause chronic and acute respiratory ailments. This study examined the lung disease-related hub genes, functions, and pathways that are affected by PM_2.5 in summer and winter in the two central megacities of Chengdu and Chongqing. PM_2.5 frequently activates lung disease-associated hub genes, most notably the transcription factor TP53. TP53 interacts with the majority of lung disease-related genes and regulates important and commonly occurring biological functions and pathways, including gland development, aging, reactive oxygen species metabolic process, the response to oxygen levels, and fluid shear stress, among others. Thus, PM_2.5 has been shown to target TP53 for regulating lung disease genes/functions/pathways, thereby influencing the occurrence and progression of lung illnesses. Notably, PM_2.5 may be associated with small cell carcinoma of the lung due to the high number of lung disease genes, hub genes, critical functions, and pathways enriched in this kind of cancer. These findings shed fresh light on the molecular pathophysiology of PM_2.5 pollution on the respiratory system in the CD-CQ Economic Circle and aid in the development of novel techniques for mitigating PM_2.5 pollution-associated respiratory illness.

Hair-growth promoting effect and anti-inflammatory mechanism of Ginkgo biloba polysaccharides

The aim of this study was to optimize the separation and purification technology of water-soluble Ginkgo biloba leaves polysaccharides (WGBP), analyze its composition characteristics, observe its hair-growth promoting effect in alopecia areata mice, clarify the polysaccharide fraction with bioactive activities, and explore its anti-inflammation mechanism. We isolated acidic polysaccharides (WGBP-A2) and purified a RG-I type polysaccharide (WGBP-A2b) with a molecular weight of 44 kDa. Results showed that WGBP-A2 could significantly increase the contents of VEGF and HGF in the skin tissue of alopecia areata mice, decrease the contents of Inflammatory factors in the serum. On a cellular level, the expressions of p-p65 and p-IκBα, TNF-α and IL-1β in HUVECs treated with WGBP-A2b were down-regulated. The bioinformatic analysis showed that the inflammation signaling pathway was significantly changed. Its specific mechanism may be related to its regulating the expression of p-p65 p-IκBα, TNF-α and IL-1β proteins in the inflammation signaling pathway.

Transcriptional analysis of gasoline engine exhaust particulate matter 2.5-exposed human umbilical vein endothelial cells reveals the different gene expression patterns related to the cardiovascular diseases

Particulate matter (PM) causes several diseases, including cardiovascular diseases (CVDs). Previous studies compared the gene expression patterns in airway epithelial cells and keratinocytes exposed to PM. However, analysis of differentially expressed gene (DEGs) in endothelial cells exposed to PM2.5 (diameter less than 2.5 μm) from fossil fuel combustion has been limited. Here, we exposed human umbilical vein endothelial cells (HUVECs) to PM2.5 from combustion of gasoline, performed RNA-seq analysis, and identified DEGs. Exposure to the IC50 concentrations of gasoline engine exhaust PM2.5 (GPM) for 24 h yielded 1081 (up-regulation: 446, down-regulation: 635) DEGs. The most highly up-regulated gene is NGFR followed by ADM2 and NUPR1. The most highly down-regulated gene is TNFSF10 followed by GDF3 and EDN1. Gene Ontology enrichment analysis revealed that GPM regulated genes involved in cardiovascular system development, tube development and circulatory system development. Kyoto Encyclopedia of Genes and Genomes and Reactome pathway analyses showed that genes related to cytokine–cytokine receptor interactions and cytokine signaling in the immune system were significantly affected by GPM. We confirmed the RNA-seq data of some highly altered genes by qRT-PCR and showed the induction of NGFR, ADM2 and IL-11 at a protein level, indicating that the observed gene expression patterns were reliable. Given the adverse effects of PM2.5 on CVDs, our findings provide new insight into the importance of several DEGs and pathways in GPM-induced CVDs.

GABARAP ameliorates IL-1β-induced inflammatory responses and osteogenic differentiation in bone marrow-derived stromal cells by activating autophagy

Bone mesenchymal stem cells (BMSCs) are the most commonly investigated progenitor cells in bone defect repair and osteoarthritis subchondral bone regeneration; however, these studies are limited by complex inflammatory conditions. In this study, we investigated whether pro-autophagic γ-aminobutyric acid receptor-associated protein (GABARAP) promotes BMSCs proliferation and osteogenic differentiation by modulating autophagy in the presence or absence of interleukin-1 beta (IL-1β) in vitro. The expression levels of all relevant factors were evaluated by qRT-PCR or western blotting where appropriate. BMSCs differentiation were assessed by Alizarin Red, alkaline phosphatase, safranin O, and Oil Red O staining. Furthermore, the interactions between autophagy and osteogenic differentiation were investigated by co-treatment with the autophagy inhibitor 3-methyladenine (3-MA). As the results, we found that treatment with recombinant human His6-GABARAP protein promoted cell proliferation, inhibited apoptosis, and reduced ROS generation by increasing autophagic activity, particularly when co-cultured with IL-1β. Moreover, His6-GABARAP could effectively increase the osteogenic differentiation of BMSCs. The expression levels of inflammatory factors were significantly decreased by His6-GABARAP treatment, whereas its protective effects were attenuated by 3-MA. This study demonstrates that GABARAP maintains BMSCs survival and strengthens their osteogenic differentiation in an inflammatory environment by upregulating mediators of the autophagy pathway.

GABARAP suppresses EMT and breast cancer progression via the AKT/mTOR signaling pathway

Few studies have focused on γ-aminobutyric acid type A (GABAA) receptor-associated protein (GABARAP) in tumor progression. We investigated the expression and importance of GABARAP in breast cancer. We analyzed the expression of GABARAP and its relationship with clinicopathological features and prognosis (TCGA). To explain the role and potential mechanism of GABARAP in regulating tumor development, we performed acquisition and loss of function experiments using cell lines and models of mouse xenotransplantation. We found that GABARAP inhibited proliferation, migration and invasion in vitro and in vivo. Notably, low levels of GABARAP induced the epithelial-mesenchymal transition (EMT). Low levels of GABARAP increased p-AKT and p-mTOR levels, and a specific AKT pathway inhibitor reversed the downregulation of GABARAP-induced tumor progression. GABARAP negatively correlated with advanced clinicopathological features in clinical specimens, such as tumor size and TNM stage. Notably, patients with low GABARAP levels had a poor prognosis. Immunohistochemistry (IHC) revealed that GABARAP expression negatively correlated with matrix metalloproteinase (MMP) 2 and MMP14. Conclusively, these data indicate that GABARAP suppresses the malignant behaviors of breast cancer likely via the AKT/mTOR pathway. The targeting of GABARAP may improve the certainty of diagnosis and treatment strategies for breast cancer.

Interleukins 6/8 and cyclooxygenase-2 release and expressions are regulated by oxidative stress-JAK2/STAT3 signaling pathway in human bronchial epithelial cells exposed to particulate matter ≤2.5 μm

Atmospheric particulate matter with a diameter ≤2.5 μm (PM2.5) can induce inflammation of the respiratory system, which is the pathological basis of asthma or other respiratory diseases; however, the underlying regulation mechanism has not been clearly addressed. The aim of this study was to explore the potential role of the oxidative stress-JAK/STAT signaling pathway in the inflammation of human bronchial epithelial cells induced by PM2.5. The human bronchial epithelial cell line 16HBE cells were stimulated with PM2.5 at 50 and 100 μg/mL doses for 12 or 24 hours. Intracellular reactive oxygen species (ROS) was detected using flow cytometry. Gene and protein expressions of JAK2, STAT3 and cyclooxygenase 2 (COX-2) were determined using reverse transcription-polymerase chain reaction and western blotting, respectively. The ratio of intracellular glutathione/glutathione disulfide (GSH/GSSG) and the levels of interleukin (IL)-6 and IL-8 in cellular supernatant were analyzed using enzyme-linked immunosorbent assay. The results indicated that PM2.5 treatment significantly increased gene expressions of JAK2/STAT3 and protein levels of p-JAK2/p-STAT3, accompanied by increased intracellular ROS levels, decreased GSH/GSSG ratio at 50 and 100 μg/mL of PM2.5, and significantly enhanced levels of IL-6, IL-8 and COX-2 at a dose of 100 μg/mL. Pretreatment with N-acetyl-l-cysteine (NAC) attenuated the oxidative stress induced by PM2.5; similarly, pretreatment with AG490 (an inhibitor of JAK) decreased the cytokine levels stimulated by PM2.5. Therefore, we concluded that PM2.5 exposure could activate oxidative stress-JAK2/STAT3 signaling pathway, elevate the levels of IL-6, IL-8 and COX-2 in 16HBE cells, which can be inhibited by the NAC or AG490.

GABARAP promotes bone marrow mesenchymal stem cells-based the osteoarthritis cartilage regeneration through the inhibition of PI3K/AKT/mTOR signaling pathway

Osteoarthritis (OA) is a degenerative disease of the cartilage prevalent in the middle-aged and elderly demographic. Direct transplantation of bone marrow mesenchymal stem cells (BMSCs) or stem cell-derived chondrocytes into the damaged cartilage is a promising therapeutic strategy for OA, but is limited by the poor survival and in situ stability of the chondrocytes. Autophagy is a unique catabolic pathway conserved across eukaryotes that maintains cellular homeostasis, recycles damaged proteins and organelles, and promotes survival. The aim of this study was to determine the role of the proautophagic γ-aminobutyric acid receptor-associated protein (GABARAP) on the therapeutic effects of BMSCs-derived chondrocytes in a rat model of OA, and elucidate the underlying mechanisms. Anterior cruciate ligament transection (ACLT) was performed in Sprague-Dawley rats to simulate OA, and the animals were injected weekly with recombinant human His6-GABARAP protein, BMSCs-derived differentiated chondrocytes (DCs) or their combination directly into the knee cartilage. The regenerative effects of GABARAP and/or DCs were determined in term of International Cartilage Repair Society scores and cartilage thickness. The combination treatment of DCs and GABARAP significantly increased the levels of the ECM proteins Col II and SOX9, indicating formation of hyaline-like cartilage, and decreased chondrocyte apoptosis and inflammation. DCs + GABARAP treatment also upregulated the mediators of the autophagy pathway and suppressed the PI3K/AKT/mTOR pathway, indicating a mechanistic basis of its therapeutic action.

Maternal exposure to fine particulate matter and the risk of fetal distress

Prenatal life exposure to fine particulate matter (aerodynamic diameter less than or equal to 2.5 µm, PM_2.5) has been linked with increased risk of adverse fetal development and birth outcomes in previous studies. However, to our knowledge, no study has investigated the association of maternal PM_2.5 with the risk of fetal distress, which is a harmful fetal status and may lead to fetal brain damage, even fetal death. Therefore, we conducted a study to determine the association between maternal PM_2.5 and fetal distress among 7835 mother-infant pairs from a birth cohort, in Wuhan, China, 2013-2015. The individual daily PM_2.5 level was assessed using land use regression model. We evaluated the association of maternal PM_2.5 level over the whole pregnancy with fetal distress by logistic regression model, and estimated the risk between PM_2.5 exposure in specific trimester and fetal distress using generalized estimating equations. We observed that per 10 µg/m³ change of maternal PM_2.5 level over the whole pregnancy was associated with 25% increased risk of fetal distress (95% confidence interval: 1.09-1.44). Further, we found PM_2.5 level in the 2nd trimester, but not in the 1st and 3rd trimesters, was associated with fetal distress. Stratified analyses indicated that the association was only significant among infants who were born in cold seasons. Our study suggested that PM_2.5 exposure during the whole pregnancy exhibited significant associations with the risk of fetal distress, and exposure in the 2nd trimester maybe the susceptible window. Further stratified analyses indicated that birth season is a possible modifier in the association.

Identification of mRNA-miRNA crosstalk in human endothelial cells after exposure of PM2.5 through integrative transcriptome analysis

PM2.5 has implications in cardiovascular adverse events, but the underlying mechanisms are still obscure. The aim of this study is to evaluate miRNA expression in endothelial cells in response to two realistic doses of PM2.5 and to identify the possible gene targets of deregulated miRNAs through microarray profiling and computational technology. As a result, there are 18 differentially expressed miRNAs between 2.5 μg/cm² group and the control, of which 11 miRNAs are up-regulated and 7 miRNAs are down-regulated. Relative to the control group, 40 miRNAs are significantly changed in 10 μg/cm² group with 21 miRNAs being upregulated and 19 miRNAs being downregulated. Interestingly, when two PM2.5-treated groups respectively compared with the control, the expressed trends of 12 miRNAs in 2.5 μg/cm² group are the same as those in 10 μg/cm² group, with 8 being upregulated and 4 miRNAs being simultaneously downregulated. Gene ontology (GO) analysis shows that the crucial functional categories of miRNA-targeted genes incorporate transcription-related process and intracellular signal transduction. Pathway analysis reveals that endocytosis, FoxO signaling pathway and PI3K-Akt signaling pathway are involved in the PM2.5-caused cardiotoxicity. Further confirmation by RT-qPCR indicates that PM2.5 could induce the down-regulation of hsa-miR-128-3p, hsa-miR-96-5p, hsa-miR-28-5p, hsa-miR-4478 and hsa-miR-6808-5p, which are in accordance with the results of array data. With the comprehensive analysis of mRNAs and miRNAs, a great number of pairs have been identified, suggesting abnormally expressed miRNAs have functions in the cardiotoxicity of PM2.5, and the function may be achieved through the post-transcriptional regulation of certain genes on the related pathways.

TMT-Based Quantitative Proteomics Analysis Reveals Airborne PM2.5-Induced Pulmonary Fibrosis

Epidemiological and experimental studies have documented that long-term exposure to fine particulate matter (PM_2.5) increases the risk of respiratory diseases. However, the details of the underlying mechanism remain unclear. In this study, male C57BL/6 mice were exposed to ambient PM_2.5 (mean daily concentration ~64 µg/m³) for 12 weeks through a "real-world" airborne PM_2.5 exposure system. We found that PM_2.5 caused severe lung injury in mice as evidenced by histopathological examination. Then, tandem mass tag (TMT) labeling quantitative proteomic technology was performed to analyze protein expression profiling in the lungs from control and PM_2.5-exposed mice. A total of 32 proteins were differentially expressed in PM_2.5-exposed lungs versus the controls. Among these proteins, 24 and 8 proteins were up- and down-regulated, respectively. Gene ontology analysis indicated that PM_2.5 exerts a toxic effect on lungs by affecting multiple biological processes, including oxidoreductase activity, receptor activity, and protein binding. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that extracellular matrix (ECM)⁻receptor interaction, phagosome, small cell lung cancer, and phosphatidylinositol 3-kinase(PI3K)-protein kinase B (Akt) signaling pathways contribute to PM_2.5-induced pulmonary fibrosis. Taken together, these results provide a comprehensive proteomics analysis to further understanding of the molecular mechanisms underlying PM_2.5-elicited pulmonary disease.

COPD rat model is more susceptible to cold stress and PM2.5 exposure and the underlying mechanism

The purpose of this study is to verify the hypothesis that chronic obstructive pulmonary disease (COPD) model rat is more susceptible to cold stress and fine particulate matter (PM_2.5) exposure than the healthy rat, and explore the related mechanism. COPD rat model, established with cigarette smoke and lipopolysaccharide intratracheal instillation, were exposed to cold stress (0 °C) and PM_2.5 (0, 3.2, 12.8 mg/ml). After that, the levels of superoxide dismutase, inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1) and angiotensin Ⅱ (Ang-Ⅱ) in lung were measured, as well as the expression levels of lung 8-hydroxy-2-deoxyguanosine (8-OHdG), nuclear factor kappa B (NF-κB), heme-oxygenase-1 (HO-1) and nuclear factor erythroid-2-related factor 2 (Nrf2). There were significant positive relationships between PM_2.5 and lung level of iNOS, TNF-α, MCP-1 and Ang-Ⅱ, lung function and pathologic damage in COPD rats. The HO-1, NF-κB and 8-OHdG were found highly expressed in COPD rat lung, particularly at the higher PM_2.5 dose of cold stress groups, while Nrf2 was found declined. Thus, COPD rats may be more susceptible to cold stress and PM_2.5 exposure. Cold stress may aggravate PM_2.5-induced toxic effects in the lung of COPD rats through increasing Ang-Ⅱ/NF-κB signaling pathway and suppressing Nrf2 signaling pathway.