Comprehensive understanding of PM2.5 on gene and microRNA expression patterns in zebrafish (Danio rerio) model

Low-level PM2.5 induces the occurrence of early pulmonary injury by regulating circ_0092363

The significant correlation between particulate matter with aerodynamic diameters of ≤ 2.5 µm (PM2.5) and the high morbidity and mortality of respiratory diseases has become the consensus of the research. Epidemiological studies have clearly pointed out that there is no safe concentration of PM2.5, and mechanism studies have also shown that exposure to PM2.5 will first cause pulmonary inflammation. Therefore, the purpose of this study is to explore the mechanism of early lung injury induced by low-level PM2.5 from the perspective of epigenetics. Based on the previous results of population samples, combined with an in vitro/vivo exposure model of PM2.5, it was found that low-level PM2.5 promoted the transport of circ_0092363 from intracellular to extracellular spaces. The decreased expression of intracellular circ_0092363 resulted in reduced absorption of miR-31-5p, leading to inhibition of Rho associated coiled-coil containing protein kinase 1 (ROCK1) and the subsequent abnormal expression of tight junction proteins such as Zonula occludens protein 1 (ZO-1) and Claudin-1, ultimately inducing the occurrence of early pulmonary injury. Furthermore, this study innovatively introduced organoid technology and conducted a preliminary exploration for a study of the relationship among environmental exposure genomics, epigenetics and disease genomics in organoids. The role of circ_0092363 in early pulmonary injury induced by low-level PM2.5 was elucidated, and its value as a potential diagnostic biomarker was confirmed.

Short-term exposure to fine particulate matter exposure impairs innate immune and inflammatory responses to a pathogen stimulus: A functional study in the zebrafish model

Short-term exposure to fine particulate matter (PM2.5) is associated with the activation of adverse inflammatory responses, increasing the risk of developing acute respiratory diseases, such as those caused by pathogen infections. However, the functional mechanisms underlying this evidence remain unclear. In the present study, we generated a zebrafish model of short-term exposure to a specific PM2.5, collected in the northern metropolitan area of Milan, Italy. First, we assessed the immunomodulatory effects of short-term PM2.5 exposure and observed that it elicited pro-inflammatory effects by inducing the expression of cytokines and triggering hyper-activation of both neutrophil and macrophage cell populations. Moreover, we examined the impact of a secondary infectious pro-inflammatory stimulus induced through the injection of Pseudomonas aeruginosa lipopolysaccharide (Pa-LPS) molecules after exposure to short-term PM2.5. In this model, we demonstrated that the innate immune response was less responsive to a second pro-inflammatory infectious stimulus. Indeed, larvae exhibited dampened leukocyte activation and impaired production of reactive oxygen species. The obtained results indicate that short-term PM2.5 exposure alters the immune microenvironment and affects the inflammatory processes, thus potentially weakening the resistance to pathogen infections.

Identification and Characterization of Immune-Associated MicroRNAs in Silver Carp (Hypophthalmichthys molitrix) Responding to Aeromonas veronii and LPS Stimulation

The ubiquitous Gram-negative bacterial pathogen Aeromonas veronii (A. veronii) can easily cause inflammatory reactions in aquatic organisms, resulting in high mortality and huge economic losses. MicroRNAs (miRNAs) participate in immune regulation and have certain conserved properties. MiRNAs are involved in the immune responses of a variety of teleost fish infected with bacteria, whereas there is no related report in silver carp (Hypophthalmichthys molitrix). Therefore, we identified the expression profiles of miRNA in silver carp stimulated by A. veronii and LPS. Among them, the quantity of differentially expressed miRNAs (DEmiRNAs) obtained in the silver carp challenge group was 73 (A. veronii) and 90 (LPS). The GO enrichment and analysis of KEGG pathways have shown that the predicted target genes are mainly associated with lipid metabolism and the immune response in silver carp. This indicates the possibility that miRNAs play a role in regulating immune-related pathways. In addition, a total of eight DEmiRNAs validated the accuracy of the sequencing result via quantitative real-time PCR (qRT-PCR). Finally, we selected the silver carp head kidney macrophage cells (HKCs) as model cells and proved that miR-30b-5p can regulate the inflammatory response in silver carp HKCs. This study lays the foundation for exploring miRNA regulation in silver carp during pathogenic bacterial infection. In addition, it provides a reference for the future development of non-coding RNA antibacterial drugs.

Diesel exhaust exposure alters the expression of networks implicated in neurodegeneration in zebrafish brains

Neurodegenerative diseases are a major cause of disability in the world, but their etiologies largely remain elusive. Genetic factors can only account for a minority of risk for most of these disorders, suggesting environmental factors play a significant role in the development of these diseases. Prolonged exposure to air pollution has recently been identified to increase the risk of Alzheimer's and Parkinson's diseases, but the molecular mechanisms by which it acts are not well understood. Zebrafish embryos exposed to diesel exhaust particle extract (DEPe) lead to dysfunctional autophagy and neuronal loss. Here, we exposed zebrafish embryos to DEPe and performed high throughput proteomic and transcriptomic expression analyses from their brains to identify pathogenic pathways induced by air pollution. DEPe treatment altered several biological processes and signaling pathways relevant to neurodegenerative processes, including xenobiotic metabolism, phagosome maturation, and amyloid processing. The biggest induction of gene expression in brains was in Cyp1A (over 30-fold). The relevance of this expression change was confirmed by blocking induction using CRISPR/Cas9, which resulted in a dramatic increase in sensitivity to DEPe toxicity, confirming that Cyp1A induction was a compensatory protective mechanism. These studies identified disrupted molecular pathways that may contribute to the pathogenesis of neurodegenerative disorders. Ultimately, determining the molecular basis of how air pollution increases the risk of neurodegeneration will help in the development of disease-modifying therapies.

Effects of particulate matter (PM2.5) on life history traits, oxidative stress, and defensome system in the marine copepod Tigriopus japonicus

Particulate matter (PM_2.5) generated in large cities creates new problems in marine ecosystems and may adversely affect its inhabitants. However, the mechanisms underlying the same remain unclear; hence, we investigated the effects of PM_2.5 on life history traits (e.g., mortality, development, and fecundity), cellular reactive oxygen species (ROS) levels, antioxidant enzyme (e.g., glutathione peroxidase [GPx], superoxide dismutase [SOD], and catalase [CAT]) activities, and the transcript levels of detoxification-related genes (cytochrome P450s [CYPs]) and antioxidant (glutathione S-transferases [GSTs]) in the copepod Tigriopus japonicus. Among the life history traits, developmental time was the only trait to significantly deviate (P < 0.05) in response to PM_2.5 (compared to that in the controls). Significant changes in ROS levels and antioxidant enzymatic activities (P < 0.05) in response to PM_2.5, suggested that PM_2.5 can induce oxidative stress, leading to adverse effects on the T. japonicus life history. In addition, PM_2.5 induced a differential regulation of various CYP and GST genes, particularly CYP307E1, GST-kappa, and GST-sigma were significantly upregulated (P < 0.05), suggesting that these genes likely play crucial roles in detoxification mechanisms and could be useful as reliable biomarkers for PM_2.5 toxicity. Overall, the results of this study provide new insights into the potential toxicity of PM_2.5.

Laser irradiation as a novel alternative to detach intact particulate matter collected on air filters

Airborne particulate matter (PM) is collected on specific filters. For subsequent testing, the PM should be detached intact from the filter. Liquid extraction (LE), the standard method to detach PM from air filter surfaces, is challenging and can be tedious. Laser irradiation has been used to characterize PM on filters, but not to detach PM from filters for subsequent testing. A feasibility study was conducted to assess the potential of laser irradiation to detach PM from air filters. Laser-detached PM was deposited on a pre-weighed glass plate. PM detachment and collection were conducted in a single step. PM-coated air filters were subjected to visual inspection, gravimetric assessment of captured PM, and spectroscopic scanning (ATR-FTIR, SEM-EDS, and XRD) before and after laser irradiation. Laser irradiation PM detachment efficiency was up to 78 %. Functional groups, elements, and minerals of PM collected on filter surfaces disappeared or significantly decreased after irradiation, demonstrating detachment, without suffering a change in their nature. No evidence of filter fragments was found in the detached PM. Laser irradiation was i) an easy, ii) rapid, and iii) single step procedure that iv) detached PM, v) didn't detach filter fragments, vi) didn't change PM composition, and vii) is amenable to automation and high throughput. Laser irradiation to detach PM from air filters as an alternative to LE is worthy of further study and development.

Role of miR-145-5p/ CD40 in the inflammation and apoptosis of HUVECs induced by PM2.5

Fine particulate matter (PM_2.5) exposure can cause the injury of vascular endothelial cells by inflammatory response. CD40 works in inflammation of endothelial cells and it may be regulated by the miRNAs. This study aimed to clarify the role and mechanism of CD40 and miR-145-5p in PM_2.5-induced injury of human umbilical vein endothelial cells (HUVECs). HUVECs were treated with different concentrations of PM_2.5 exposure (0, 100, 200, 400 μg/mL) for 24 h. The si-RNA was used for CD40 gene silencing (0, 200 μg/mL PM_2.5, siRNA-CD40 and siRNA-CD40 + 200 μg/mL PM_2.5). Mimics was used for overexpression of miR-145-5p (0, 200 μg/mL PM_2.5, mimics and mimics+200 μg/mL PM_2.5). The cell viability of HUVECs was detected with Cell Counting Kit8 (CCK8) kit. The level of cell apoptosis was detected by flow cytometry. The inflammation-related factor including interleukin-1β (IL-1β), interleukin-18 (IL-18), tumor necrosis factor α (TNF-α) and C1q complement/tumor necrosis factor (TNF)-associated proteins9 (CTRP9) were tested with enzyme-linked immunosorbent assay (ELISA) kits. The mRNA and protein expression levels of CD40, CD40L, caspase1, NLRP3 (Nod-like receptor family pyrin domain-containing 3) and IKKB were detected with quantitative real-time PCR (qRT-PCR), Western blot and Immunofluorescence. Compared with the control group, the cell viability of HUVECs exposed to PM_2.5 was significantly decreased (p < 0.05); the levels of IL-Iβ and TNF-α were significantly increased, while the level of CTRP9 was significantly decreased (p < 0.05). The proportion of apoptotic cells was increased after being treated with PM_2.5 (p < 0.05). Besides, the mRNA and protein levels of CD40, CD40L, IKKB, NLRP3 and caspase1 were increased comparing with the control group (p < 0.05). After CD40 silencing, the condition of inflammation and apoptosis in HUVECs exposed to PM_2.5 was alleviated, and the expression levels of CD40L, IKKB, NLRP3 and caspase1 were significantly decreased (p < 0.05). Furthermore, miR-145-5p was significantly down-regulated after exposure to 200μg/mL PM_2.5 (p < 0.05). After over-expression of miR-145-5p, the expression level of CD40 was decreased (p < 0.05). Taken together, PM_2.5 can cause inflammation and apoptosis of HUVECs via the activation of CD40, which can be regulated by miR-145-5p. Over-expression of miR-145-5p can down-regulate CD40, further inhibiting the inflammation and apoptosis of HUVECs induced by PM_2.5.

Developmental toxicity induced by particulate matter (PM2.5) in zebrafish (Danio rerio) model

Contemporary research in epidemiology has found that being exposed to air pollution at an early stage of life has associations with both acute and chronic conditions of the multi-organs. Nevertheless, the reasons for this have yet to be fully explained. Because of this there is a need for a robust investigation into the damaging toxic influence of diesel particulate matter (PM2.5) on living organisms. This study is aimed to investigate the developmental toxicity of PM2.5 by using zebrafish (Danio rerio) embryo/larvae as a disease model and to understand the toxicity effects of PM2.5 on ecological environment more thoroughly. This research demonstrates that being exposed to PM2.5 leads to a significant increase in mortality, effective developmental morphology, reductions in hatching rates and lower heart rates in zebrafish. Additionally, it leads to increases in the length of string heart, area of pericardium, and apoptosis, reduces the number of normal intersegmental vessels (ISVs) and motor neurons in the trunk region and liver formation defects in zebrafish embryos. Investigation employing a scanning electron microscope demonstrates that being exposed to PM2.5 leads to damage in zebrafish larvae skin cell layers. Histological analysis demonstrates that when these larvae are treated with PM2.5 then abnormalities occur in the neurons, liver, heart, gills, brain, and eyes, and remarkable increase in in the cellular/subcellular levels of organelle dissolution. These findings are useful to help us understand the pathophysiological influence of being exposed to PM2.5 on the multi-organ defects of zebrafish. More research into which particular elements that make up diesel pollution contribute to this toxicity is needed so that the dangers to development can be further analysed.

Identification of exosome miRNAs in bronchial epithelial cells after PM2.5 chronic exposure

Numerous epidemiological studies have demonstrated that chronic PM2.5 exposure was associated with the lung carcinogenesis without known potential mechanisms. Exosomes-derived non-coding RNAs, including miRNAs, are proposed to play critical role in the occurrence and development of malignant diseases. So identification of exosomes-derived miRNAs could help us to better understand the molecular toxicity of PM2.5-induced lung cancer. Establishment chronic exposure animal and cell model with PM2.5 was conducted as before. HE staining was used for estimating the histological alternations of lungs in vivo. The expressions of EMT markers in vivo and vitro were quantified by Western blot. Then the exosomes in cell culture supernatant were extracted and the involved miRNAs were extracted and sequenced. The different expression level of miRNAs were verified by RT-PCR. Chronic PM2.5 exposure induced bronchial epithelial cell atypical hyperplasia and massive macrophage infiltration. PM2.5 exposure induce EMT event in vivo and vitro indicated as increased expression of Vimentin and decreased expression of E-cadherin. And five passages of PM2.5 stimulation also induced the release of rich and extractable exosomes in the cell culture supernatant in vitro. Through sequencing, there were differentially expressed 36 miRNAs between PM2.5 chronic exposed and control groups with 1.5-fold and greater differences. Among them, there were 30 exosome-miRNAs upregulated and 6 downregulated expression by PM2.5 exposure. The downregulated expression of miR-29b-2-5p, miR-193b-5p and miR-320c and upregulated expression of miR-100-5p, 125b-5p and unconservative_2_45093 in PM2.5 group were identified and reconfirmed by qRT-PCR. Chronic PM2.5 exposure causes bronchial epithelial cells atypical hyperplasia and induces EMT event in vivo, and it also induce the expression differences of miRNAs in exosome in vitro. Meanwhile, the identified differentially expressed exosome-miRNAs may partially associate with tumorigenesis. To sum up, the identified exosome-miRNAs may play role in the development of lung cancer induced by chronic PM2.5 exposure.

Recent Application of Zebrafish Models in Atherosclerosis Research

Atherosclerotic cardiovascular disease is one of the leading causes of death worldwide. Establishing animal models of atherosclerosis is of great benefit for studying its complicated pathogenesis and screening and evaluating related drugs. Although researchers have generated a variety of models for atherosclerosis study in rabbits, mice and rats, the limitations of these models make it difficult to monitor the development of atherosclerosis, and these models are unsuitable for large scale screening of potential therapeutic targets. On the contrast, zebrafish can fulfill these purposes thanks to their fecundity, rapid development ex utero, embryonic transparency, and conserved lipid metabolism process. Thus, zebrafish have become a popular alternative animal model for atherosclerosis research. In this mini review, we summarize different zebrafish models used to study atherosclerosis, focusing on the latest applications of these models to the dynamic monitoring of atherosclerosis progression, mechanistic study of therapeutic intervention and drug screening, and assessment of the impacts of other risk factors.

Determination of Genotoxicity Attributed to Diesel Exhaust Particles in Normal Human Embryonic Lung Cell (WI-38) Line

Several epidemiological studies concluded that inhalation of diesel exhaust particles (DEP) is associated with an increase in the relative risk of lung cancer. In vitro research evaluating the genetic damage and/or changes in gene expression have been attempted to explain the relationship between DEP exposure and carcinogenicity. However, to date, investigations have been largely confined to studies in immortalized or tumorigenic epithelial cell models. Few studies have investigated damage at the chromosomal level to DEP exposure in normal cell lines. Here, we present the genotoxic effects of DEP in normal cells (embryonic human lung fibroblasts) by conventional genotoxicity testing (micronuclei (MN) and comet assay). We show the differentially expressed genes and enriched pathways in DEP-exposed WI-38 cells using RNA sequencing data. We observed a significant increase in single-strand DNA breaks and the frequency of MN in DEP-exposed cells in a dose-dependent manner. The differentially expressed genes following DEP exposure were significantly enriched in the pathway for responding to xenobiotics and DNA damage. Taken together, these results show that DEP exposure induced DNA damage at the chromosomal level in normal human lung cells and provide information on the expression of genes associated with genotoxic stress.

Long-term wet precipitation of PM2.5 disturbed the gut microbiome and inhibited the growth of marine medaka Oryzias melastigma

Wet precipitation, as an important process of geochemical cycling and the most effective way of cleaning fine atmospheric particles (PM_2.5), can introduce the toxic substances in the atmosphere into the water environment. The adverse effect of wet precipitation of PM_2.5 on marine fish is still unclear. In this study, PM_2.5 samples were collected from six locations along coastal areas of the south China sea for 30 days and used to simulate the impacts of multiday discontinuity wet precipitation of PM_2.5 on marine medaka (Oryzias melastigma) in the case of 30 days discontinuity heavy rain (rainfall ≥ 7.6 mm/h and persist 1 h each day). Results showed that wet precipitation of PM_2.5 significantly inhibited the body weight gain of fish. In accordance, the size and number of lipid droplets in liver of the exposed groups were lower than those in normal control (NC) group. The expressions of genes involving in lipid degradation including lipoprotein lipase gene (LPL) and carnitine palmitoyltransferase gene (CPT) were up-regulated after exposure. The composition, diversity and function of gut microbiome were affected by wet precipitation of PM_2.5. PM_2.5 from industrial areas that have higher concentrations of metal profiles show more obvious impacts than PM_2.5 from agricultural leisure areas that possessed lower concentrations. All together, the results indicated that wet precipitation of PM_2.5 can decrease the diversity of gut microbiome, affect the lipid metabolism, and finally suppress the growth of marine medaka. It confirmed the potential ecological risks of long-term rainfall in air pollution areas to the aquatic organisms.

Cooperative application of transcriptomics and ceRNA hypothesis: LncRNA-107052630/miR-205a/G0S2 crosstalk is involved in ammonia-induced intestinal apoptotic injury in chicken

Ammonia (NH₃), as a harmful gas from agricultural production, plays an important role in air pollution, such as haze. Although numerous researchers have paid attention to health damage through NH₃ inhalation, the exhaustive mechanism of NH₃ induced intestinal toxicity remains unclear. A genes crosstalk named competing endogenous RNAs (ceRNA) can explain many regulatory manners from the molecular perspective. However, few studies have attempted to interpret the injury mechanism of air pollutants to the organism via ceRNA theory. Here, we thoroughly investigated the lncRNA-associated-ceRNA mechanism in jejunum samples from a 42-days-old NH₃-exposed chicken model through deep RNA sequencing. We observed the occurrence of apoptosis in jejunum, obtained 46 significantly dysregulated lncRNAs and 30 dysregulated miRNAs, and then constructed lncRNA-associated-ceRNA networks in jejunum. Importantly, a network regulating G0S2 in NH₃-induced apoptosis was discovered. Research results showed that G0S2 was upregulated in jejunum of NH₃-exposed group and was associated with activation of the mitochondrial apoptosis pathway. G0S2 antagonized the anti-apoptotic effect of Bcl2, which could be reversed by miR-205a. Meanwhile, lncRNA-107052630 acted as ceRNA to affect G0S2 function. These data provide new insight for revealing the biological effect of NH₃ toxicity, as well as the environmental research.

PM2.5 downregulates MicroRNA-139-5p and induces EMT in Bronchiolar Epithelium Cells by targeting Notch1

PM2.5 was closely linked to lung cancer worldwide. However, the mechanism involved in PM2.5 induced lung cancer is still largely unknown. In this study, we performed chronic PM2.5 stimulation animal and cells model to investigate the carcinogenetic mechanisms of PM2.5 by targeting EMT through Notch1 signal pathway. Next, we focused on the miRNA involved in PM2.5 induced Notch1 pathway activation. We found chronic PM2.5 could induce EMT event in vivo and in vitro, while reducing miR-139-5p expression and activating Notch1 pathway meanwhile. And blocking Notch1 signal pathway by specific small molecule inhibitor could reverse PM2.5 induced EMT. Then, overexpression of miR-139-5p downregulated the expression of Notch1 protein in untreated 16HBE cells. Importantly, overexpression of miR-139-5p blocked Notch1 pathway activation and inhibited EMT event in PM2.5 treated cells. These results indicate that PM2.5 induces EMT event through Notch1 signal pathway and miR-139-5p is a novel regulator of PM2.5-induced EMT by targeting Notch1. Our conclusion is that overexpression of miR-139-5p can down-regulate the expression of Notch1 and reverse the occurrence of malignant lung events induced by chronic exposure to PM2.5.

MicroRNAs and Xenobiotic Toxicity: An Overview

The advent of new technologies has paved the rise of various chemicals that are being employed in industrial as well as consumer products. This leads to the accumulation of these xenobiotic compounds in the environment where they pose a serious threat to both target and non-target species. miRNAs are one of the key epigenetic mechanisms that have been associated with toxicity by modulating the gene expression post-transcriptionally. Here, we provide a comprehensive view on miRNA biogenesis, their mechanism of action and, their possible role in xenobiotic toxicity. Further, we review the recent in vitro and in vivo studies involved in xenobiotic exposure induced miRNA alterations and the mRNA-miRNA interactions. Finally, we address the challenges associated with the miRNAs in toxicological studies.

Zebrafish as an integrative vertebrate model to identify miRNA mechanisms regulating toxicity

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Zebrafish are an established vertebrate model for toxicity studies.

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Zebrafish have a fully sequenced genome and the capability to create genetic models.

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Zebrafish have over 80 % homology for genes related to human disease.

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Functions of miRNAs in the zebrafish genome are being characterized.

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Zebrafish are ideal for mechanistic studies on how miRNAs regulate toxicity.

Zebrafish (Danio rerio) are an integrative vertebrate model ideal for toxicity studies. The zebrafish genome is sequenced with detailed characterization of all life stages. With their genetic similarity to humans, zebrafish models are established to study biological processes including development and disease mechanisms for translation to human health. The zebrafish genome, similar to other eukaryotic organisms, contains microRNAs (miRNAs) which function along with other epigenetic mechanisms to regulate gene expression. Studies have now established that exposure to toxins and xenobiotics can change miRNA expression profiles resulting in various physiological and behavioral alterations. In this review, we cover the intersection of miRNA alterations from toxin or xenobiotic exposure with a focus on studies using the zebrafish model system to identify miRNA mechanisms regulating toxicity. Studies to date have addressed exposures to toxins, particulate matter and nanoparticles, various environmental contaminants including pesticides, ethanol, and pharmaceuticals. Current limitations of the completed studies and future directions for this research area are discussed.

MALAT1 affects hypoxia-induced vascular endothelial cell injury and autophagy by regulating miR-19b-3p/HIF-1α axis

Cardiovascular disease has become the leading cause of death in the world. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays an important role in cardiovascular disease, such as stroke. However, the role of MALAT1 in hypoxia (HYP)-induced vascular endothelial cells (VECs) remains unclear. In the present study, HYP-treated human umbilical vein endothelial cells (HUVECs) were utilized to simulate HYP-induced VEC injury. It was found that after HYP treatment, the levels of MALAT1 and hypoxia-induced factor-1 (HIF-1α) in HUVECs were upregulated, while the level of miR-19b-3p was downregulated. Knockdown of MALAT1 with siRNA significantly reduced the HIF-1α level induced by HYP. In addition, MALAT1 knockdown inhibited HYP-induced HUVECs apoptosis, autophagy and inflammation. The overexpression of HIF-1α overcame the effect of MALAT1 knockdown. Mechanism analysis showed that MALAT1-targeted miR-19b-3p and then regulated downstream HIF-1α. MALAT1 knockdown increased the level of miR-19b-3p in cells, and increased miR-19b-3p further inhibited the expression of HIF-1α, thereby reducing the HYP-induced HUVECs apoptosis, autophagy and inflammation. Taken together, these results suggest that MALAT1 may be a potential target for mitigating HYP-induced endothelial cell injury.

PM2.5 inhibits SOD1 expression by up-regulating microRNA-206 and promotes ROS accumulation and disease progression in asthmatic mice

Bronchial asthma is the most common chronic respiratory disease. Chronic airway inflammation, airflow restriction and airway hyper-responsiveness are its main manifestations. In recent decades, the prevalence and mortality of asthma have been increasing all over the world, which seriously threatens public health. Research suggests that air pollution is associated with the increased incidence of asthma. PM2.5 is one of the most complex pollutants in the atmospheric environment and harmful to human health. It is related to the incidence of asthma. However, the molecular mechanism of PM2.5 in the development of asthma is still unclear. In this study, we established a mouse model of asthma using CRE to observe the effect of PM2.5 on the symptoms of asthmatic mice and its possible molecular mechanism. The results showed that PM2.5 could significantly increase airway resistance and pulmonary inflammation, increase the number of inflammatory cells, eosinophils, macrophages, neutrophils and lymphocytes in bronchoalveolar lavage fluid in asthmatic mice. Moreover, PM2.5 could reduce the contents of antioxidant enzymes such as CAT, GSH, GSH-Px and T-SOD in lung tissue of mice, and increase the ROS level. PM2.5 can promote the expression of microRNA-206 in lung tissue of mice. miR-206 can target the 3'-UTR of SOD1 to inhibit SOD1 expression, which leads to the increase of ROS level and aggravates pulmonary inflammatory response and asthma symptoms in asthmatic mice. This study found the possible molecular mechanism of PM2.5 aggravating asthma, and miR-206 may be a potential target for asthma treatment.

Skin inflammation induced by ambient particulate matter in China

Most published studies on particulate matter (PM) concerning PM_2.5 and PM₁₀ have focused on PM-induced effects on the respiratory system (particularly lung) and cardiovascular system effects. However, epidemiological and mechanistic studies suggest that PM_2.5 and PM₁₀ also affects the skin, which is a key health issue. In this study, we first reviewed the current status of PM_2.5 and PM₁₀ in China, including relevant regulations, concentration levels, chemical components, and emission sources. Next, we summarized the association between PM_2.5 and PM₁₀ or its representative components, in relation to skin inflammation as well as inflammatory skin diseases, such as atopic dermatitis, acne, eczema, and skin aging. Finally, we determined the mechanism of oxidative stress or programmed cell death induced through PM, which can provide useful information for future research on PM-induced skin inflammation.

Coupling Genome-wide Transcriptomics and Developmental Toxicity Profiles in Zebrafish to Characterize Polycyclic Aromatic Hydrocarbon (PAH) Hazard

Polycyclic Aromatic Hydrocarbons (PAHs) are diverse environmental pollutants associated with adverse human health effects. Many studies focus on the carcinogenic effects of a limited number of PAHs and there is an increasing need to understand mechanisms of developmental toxicity of more varied yet environmentally relevant PAHs. A previous study characterized the developmental toxicity of 123 PAHs in zebrafish. Based on phenotypic responses ranging from complete inactivity to acute mortality, we classified these PAHs into eight bins, selected 16 representative PAHs, and exposed developing zebrafish to the concentration of each PAH that induced 80% phenotypic effect. We conducted RNA sequencing at 48 h post fertilization to identify gene expression changes as a result of PAH exposure. Using the Context Likelihood of Relatedness algorithm, we inferred a network that links the PAHs based on coordinated gene responses to PAH exposure. The 16 PAHs formed two broad clusters: Cluster A was transcriptionally more similar to the controls, while Cluster B consisted of PAHs that were generally more developmentally toxic, significantly elevated cyp1a transcript levels, and induced Ahr2-dependent Cyp1a protein expression in the skin confirmed by gene-silencing studies. We found that cyp1a transcript levels were associated with transcriptomic response, but not with PAH developmental toxicity. While all cluster B PAHs predominantly activated Ahr2, they also each enriched unique pathways like ion transport signaling, which likely points to differing molecular events between the PAHs downstream of Ahr2. Thus, using a systems biology approach, we have begun to evaluate, classify, and define mechanisms of PAH toxicity.

In silico prediction of MicroRNA role in regulation of Zebrafish (Danio rerio) responses to nanoparticle exposure

The release of nanoparticles to the environment can affect health of the exposed organisms. MicroRNAs have been suggested as potential toxicology biomarkers, however the information about use of microRNA in aquatic organisms exposed to nanoparticles (NP) is limited. In silico analysis from publicly available gene expression data was performed. Data selection for the analysis was based on reported biological and pathological outcomes of NP induced toxicity in zebrafish. After identifying relevant genes, we constructed six miRNA-mRNA regulatory networks involved in nanoparticle induced toxicological responses in zebrafish. Based on our prediction and selection criteria we selected six miRNAs that overlapped in constructed networks with remarkable prediction score, and were validated by previous mammalian and zebrafish microRNA profiling studies: dre-miR-124, -144, -148, -155, -19a, -223. The results of this in silico analysis indicate that several highly conserved miRNAs likely have a regulatory role of organismal responses to nanoparticles, and can possibly be used as biomarkers of nanotoxicity in studies using zebrafish as model organism One health approaches.

Repeat dose exposure of PM2.5 triggers the disseminated intravascular coagulation (DIC) in SD rats

Epidemiological evidence suggests that fine particulate matter (PM_2.5) in air pollution promotes the formation of deep venous thrombosis. However, no evidence is available on the effects of PM_2.5 lead to disseminated intravascular coagulation (DIC). For the first time, this study explored the effects of PM_2.5 on DIC via coagulation disorders in vivo. SD rats received intratracheal instillation of PM_2.5 once every three days for one month. Doppler ultrasound showed that the pulmonary valve (PV) and aortic valve (AV) peak flow were decreased after exposure to PM_2.5. Fibrin deposition and bleeding were observed in lung tissue and vascular endothelial injury was found after exposure to PM_2.5. Expression of thrombomodulin (TM) in vessel was downregulated after PM_2.5-treated, whereas the levels of proinflammatory factors and adhesion molecules (IL-6, IL-1β, CRP, ICAM-1 and VCAM-1) were markedly elevated after exposure to PM_2.5. Tissue factor (TF) and the coagulation factor of FXa were increased, while vWF was significantly lowered induced by PM_2.5. Thrombin-antithrombin complex (TAT) and fibrinolytic factor (t-PA) were elevated, while there was no significantly change in the expression of anticoagulant factors (TFPI and AT-III). To clarify the relationship between PM_2.5 and DIC, we examined the general diagnostic indices of DIC: PM_2.5 prolonged PT and increased the expression of D-dimer but decreased platelet count and fibrinogen. In addition, the gene levels of JAK1 and STAT3 showed an upward trend, whereas there was little effect on JAK2 expression. And inflammatory factors (IL-6, IL-1β and TNF) in blood vessels of were up-reglated in PM_2.5-treated rats. In summary, our results found that PM_2.5 could induce inflammatory response, vascular endothelial injury and prothrombotic state, eventually resulted in DIC. It will provide new evidence for a link between PM_2.5 and cardiovascular disease.

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.

Genome-wide identification and functional analysis of long non-coding RNAs in human endothelial cell line after incubation with PM2.5

Epidemiological studies and experimental research have illustrated that PM2.5 has an association with cardiovascular adverse events. However, the underlying mechanisms are still unknown. Long non-coding RNAs (lncRNAs) have been proposed to take part in diverse diseases. To comprehensively gain insight into the molecular toxicity of PM2.5, expression patterns are analyzed in EA.hy926 cell line through RNAs microarray. A total of 356 lncRNA transcripts are dysregulated in 2.5 μg/cm² group, and there are 1283 lncRNAs differentially expressed in 10 μg/cm² group. From functional analysis, several lncRNAs may be implicated in the bio-pathways of phagosome, TNF signaling pathway, chemokine signaling pathway and gap junction. Moreover, certain lncRNAs participate in the toxicity of PM2.5 through cis- and/or trans-regulation of their co-expressed genes. Therefore, lncRNAs may be used as new candidate biomarkers and potentially preventive targets in cardiotoxicity of PM2.5. Our study indicates that not limited to transcriptional regulation, post-transcriptional regulation plays a pivotal role in PM2.5-caused toxicity.

MicroRNAs and their role in environmental chemical carcinogenesis

MicroRNAs (miRNAs) are a class of small, noncoding RNA species that play crucial roles across many biological processes and in the pathogenesis of major diseases, including cancer. Recent studies suggest that the expression of miRNA is altered by certain environmental chemicals, including metals, organic pollutants, cigarette smoke, pesticides and carcinogenic drugs. In addition, extensive studies have indicated the existence and importance of miRNA in different cancers, suggesting that cancer-related miRNAs could serve as potential markers for chemically induced cancers. The altered expression of miRNA was considered to be a vital pathogenic role in xenobiotic-induced cancer development. However, the significance of miRNA in the etiology of cancer and the exact mechanisms by which environmental factors alter miRNA expression remain relatively unexplored. Hence, understanding the interaction of miRNAs with environmental chemicals will provide important information on mechanisms underlying the pathogenesis of chemically induced cancers, and effectively diagnose and treat human cancers resulting from chronic or acute carcinogen exposure. This study presents the current evidence that the miRNA deregulation induced by various chemical carcinogens, different cancers caused by environmental carcinogens and the potentially related genes in the onset or progression of cancer. For each carcinogen, the specifically expressed miRNA may be considered as the early biomarkers of the cancer process. In this review, we also summarize various target genes of the altered miRNA, oncogenes or anti-oncogenes, and the existing evidence regarding the gene regulation mechanisms of cancer caused by environmentally induced miRNA alteration. The future perspective of miRNA may become attractive targets for the diagnosis and treatment of carcinogen-induced cancer.

PM2.5 Upregulates MicroRNA-146a-3p and Induces M1 Polarization in RAW264.7 Cells by Targeting Sirtuin1

Background: Fine particulate matter (PM_2.5) exposure is proved to be associated with illnesses, but the mechanism is not clear. Potential effects of PM_2.5 on innate immunity have become a hotspot recently. Confronting PM_2.5, macrophages are able to be activated and induce inflammatory responses. Whether PM_2.5 exposure affects macrophage polarization and associated mechanisms remains to be further explored. Afterwards, whether Sirtuin1 (SIRT1) an important intermediate regulator in various physiological processes takes part in the macrophage polarization induced by PM_2.5 is unknown. MiRNAs are acknowledged as key regulator in posttranscriptional modification and our previous study found that miR-146a is a novel biomarker of PM_2.5 exposure. Thus, we propose a hypothesis, PM_2.5 exposure induces M1 polarization and miR-146a-3p is a potential upstream regulator by targeting SIRT1. Methods: RAW264.7 cells were treated with different concentrations of PM_2.5 for 24h. The expressions of cytokines and key molecular markers were detected by qRT-PCR, Western blotting and ELISA. The activation degree of TLRs and NF-κB was assessed by Western blotting. The specific agonist and antagonist of SIRT1 were used to explore the potential role of SIRT1 in M1 polarization induced by PM_2.5. MiR-146a-3p mimic and inhibitor were pre-transfected into RAW264.7 cells and the effects on M1 polarization induced by PM_2.5 were evaluated. Luciferase analysis was used to identify the binding site of miR-146a-3p and SIRT1. Results: PM_2.5 increased the mRNA and protein expression of M1 markers including interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase (iNOS) in RAW264.7 cells. The protein level of TLR4 was significantly increased and the ratio of phosphorylated NF-κB p65 versus p65 subunit was also elevated in PM_2.5 group. PM_2.5 decreased the protein level of SIRT1 but not the mRNA expression in vitro and in vivo experiments. Pre-treatment with SIRT1 agonist SRT1720 rescued the PM_2.5 induced M1 response. Whereas, SIRT1 antagonist EX527 augment the effect. MiR-146a-3p was upregulated in PM_2.5 treated RAW264.7 cells. Luciferase experiments reported that SIRT1 was directly targeted by miR-146a-3p. Overexpression of miR-146a-3p downregulated the expression of SIRT1 protein in untreated RAW264.7 cells. Importantly, inhibition of miR-146a-3p upregulated SIRT1 protein and suppressed M1 polarization in PM_2.5 treated RAW264.7 cells. Conclusions: These results suggested that PM_2.5 induces the inflammatory M1 polarization and TLR4/NF-κB signal transduction pathway might be involved in the process. MiR-146a-3p is a novel regulator of PM_2.5 exerted M1 polarization by targeting SIRT1.

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.

Analysis of differentially changed gene expression in EA.hy926 human endothelial cell after exposure of fine particulate matter on the basis of microarray profile

Epidemiological studies have illustrated that PM2.5 is closely related to cardiovascular disease (CVD), but underlying toxicological mechanisms are not yet clear. The main purpose of this study is to disclose the potential biological mechanisms responsible for PM2.5-dependent adverse cardiovascular outcomes through the appliance of genome-wide transcription microarray. From results, compared with the control group, there are 97 genes significantly altered in 2.5 μg/cm² PM2.5 treated group and 440 differentially expressed genes in 10 μg/cm² group. Of note, when 2.5 μg/cm² and 10 μg/cm² group were respectively compared with the control group, 46 significantly altered genes showed a consistent tendency in two treated groups, of which 31 genes were upregulated while 15 genes were meanwhile downregulated. Based on Gene Ontology (GO) annotation, altered genes are mainly gathered in functions of cellular processes and immune regulation. Pathway analysis indicated that TNF signaling pathway, NOD-like receptor (NLRs) signaling pathway, MAPK signaling pathway and gap junction are vital pathways involved in PM2.5-induced toxicity in EA.hy926. Moreover, results from RT-qPCR further corroborated that changed genes are implicated in oxidative stress, inflammation and metabolic disorder. In addition, metabolism of xenobiotics by cytochrome P450 pathway is the critical pathway which may serve as a target to prevent PM2.5-induced CVD. To sum up, our effort provides a fundamental data for further studies regarding mechanisms of PM2.5-induced cardiovascular toxicity on the basis of genome-wide screening.

miR-486 inhibits PM2.5-induced apoptosis and oxidative stress in human lung alveolar epithelial A549 cells

Background

Environmental exposure to particulate matter 2.5 (PM2.5) threatens public health, which has caused worldwide concerns. MicroRNAs (miRNAs, miRs) participate in multiple biological regulation. Among them, miR-486 has been reported to be a beneficial molecule for cell survival in various cell types. However, the potential function of miR-486 in PM2.5-induced cytotoxic is still uncertain.

Methods

The expression of miR-486 was detected by quantitative real-time polymerase chain reaction (qRT-PCR) after A549 cells incubated with PM2.5. Then TUNEL staining and DCFH-DA fluorescence were used to test the apoptosis and ROS generation of A549 cells after exposed to PM2.5 with miR-486 mimic. Western blot was performed to determine the expression of Bax/Bcl2 ratio. In addition, western blot and rescue experiments were conducted to determine the target gene of miR-486.

Results

After treated with PM2.5, the expression of miR-486 was decreased. And miR-486 mimic treatment reduced cell apoptosis and reactive oxygen species (ROS) generation induced by PM2.5 exposure. Further studies showed that miR-486 negatively regulated the protein levels of PTEN and FOXO1. Rescue experiments demonstrated that PTEN and FOXO1 mediated the protective effects of miR-486 in PM2.5-treated human lung alveolar epithelial A549 cells.

Conclusions

Collectively, our findings identify that miR-486 relieves PM2.5-induced cell injury by targeting PTEN and FOXO1 in human lung alveolar epithelial A549 cells.

Developmental toxicity induced by PM2.5 through endoplasmic reticulum stress and autophagy pathway in zebrafish embryos

The aims of this study were to investigate the mechanism underlying the developmental toxicity of fine particulate matter (PM_2.5) and provide a more thorough understanding of the toxicity of PM_2.5 in an ecological environment. Zebrafish embryos at 4 h post-fertilization were exposed to PM_2.5 at doses of 200, 300, 400, 500, 600 and 800 μg/mL for 120 h. The mortality, hatching rate, morphology score, body length, locomotor capacity, histological changes, antioxidant defense system, leukocyte migration, inflammation-related gene mRNA expression, endoplasmic reticulum stress (ERS) and autophagy were evaluated to study PM_2.5-induced developmental toxicity and its underlying mechanisms. PM_2.5 exposure significantly increased the mortality and malformations and reduced the hatching rate and body length of the zebrafish. PM_2.5 significantly reduced the locomotor capacity of zebrafish larvae, increased the levels of ROS and disturbed the antioxidant defense system in zebrafish larvae. In addition, a histological examination showed that the heart, liver, intestines and muscle of the PM_2.5-treated zebrafish exhibited abnormal changes and a significant increase in cellular autophagic accumulation. RT-PCR showed that the expression of genes related to inflammation (tgfβ and cox2), ERS (hspa5, chop, ire1, xbp1s, and atf6) and autophagy (lc3, beclin1 and atg3) pathways was significantly increased in the PM_2.5-treated zebrafish, indicating that PM_2.5 induced inflammation and promoted ERS and autophagy responses via the activation of the IRE1-XBP1 and ATF6 pathways. Together, our data indicate that PM_2.5 induced a dose- and time-dependent increase in developmental toxicity to zebrafish embryos. Additionally, ERS and autophagy may play important roles in PM_2.5-induced developmental toxicity.

Effect of 1-methyl-3-hexylimidazolium bromide on zebrafish (Danio rerio)

Room-temperature ionic liquids, generally referred to ionic liquids (ILs), are "green solvents". Antioxidant responses and DNA damage in zebrafish livers exposed to 1-methyl-3-hexylimidazolium bromide ([C₆mim]Br) were evaluated at various doses (5-40 mg/L) for a 28-day IL-exposure. A significant decrease of superoxide dismutase (SOD) activity was exhibited, and catalase (CAT) was inhibited at the highest dose (40 mg/L). Reactive oxygen species (ROS) levels were significantly promoted at most exposure interval times except for the dose of 5 mg/L on day 21 in male and days 21 and 28 in female. Malonaldehyde (MDA) contents remarkable increased exposed to [C₆mim]Br. Besides, a notable increase was exhibited, which indicated an inducement of DNA damage with respect to control groups. Thus, we believed that [C₆mim]Br causes oxidative stress and DNA damage in zebrafish. Gender differences were insignificant in almost all the tested biomarkers, thus, male and female zebrafish could be mixed at a ratio of 1:1 in the future evaluation. The present study may also provide basic toxicology information for IL evaluation to aquatic organisms.

Acute and chronic toxic effects of fluoxastrobin on zebrafish (Danio rerio)

Fluoxastrobin is a new strobilurin fungicide, similar to azoxystrobin and pyraclostrobin. Before the wide application of fluoxastrobin, the present study was performed to assay the acute and chronic toxicity of fluoxastrobin on zebrafish (Danio rerio). The 96-hour median lethal concentration (96h LC₅₀) after initiation of zebrafish exposure to fluoxastrobin was 0.51mg/L with a 95% confidence interval of 0.45 to 0.57mg/L, indicating that fluoxastrobin was highly toxic to zebrafish. As endpoints, we assayed the levels of reactive oxygen species (ROS), malondialdehyde (MDA), the activities of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and the degree of DNA damage at three different doses, 0.001, 0.01, and 0.1mg/L on days 7, 14, 21, and 28. The antioxidant enzymes partially ameliorated the ROS induced by fluoxastrobin t and were in turn inhibited by excess ROS, especially at 0.1mg/L. Lipid peroxidation and DNA damage were stimulated by ROS. The fluoxastrobin contents of the tested solutions were also determined; at the fluoxastrobin doses of 0.001, 0.01, and 0.1mg/L, the contents on day 28 were 3.9, 5.0, and 0.64% greater than those on day 0. Thus, fluoxastrobin was relatively stable in an aquatic environment. In addition, the present study provided more information regarding the toxic effects of fluoxastrobin and the scientific methods for selection and evaluation of fungicides in the future.

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

Cardiovascular system is demonstrated the main target of PM_2.5 and the objective of this study was to explore the toxic effect and molecular mechanisms caused by PM_2.5 in primary human umbilical vein endothelial cells (HUVECs) using microarray and bioinformatics analysis. The results showed that 591 genes were differentially expressed triggered by PM_2.5, of which 174 genes were down-regulated, while 417 genes were up-regulated. Gene ontology analysis revealed that PM_2.5 caused significant changes in gene expression patterns, including response to stimuli, immune response, and cellular processes. Pathway analysis and Signal-net analysis suggested that endocytosis, chemokine signaling pathway, RNA transport, protein processing in endoplasmic reticulum (ER) and autophagy regulation were the most critical pathways in PM_2.5-induced toxicity in HUVECs. Moreover, gene expression confirmation of LIF, BCL2L1, CSF3, HMOX1, RPS6, PFKFB, CAPN1, HSPBP1, MOGS, PREB, TUBB2A, GABARAP by qRT-PCR indicated that endocytosis might be involved in the cellular uptake of PM_2.5 by forming phagosomes, and subsequently inflammation, hypoxia and ER stress was occurred, which finally activated autophagy after PM_2.5 exposure in HUVECs. In summary, our data can serve as fundamental research clues for further studies of PM_2.5-induced toxicity in HUVECs.

Multi-organ toxicity induced by fine particulate matter PM2.5 in zebrafish (Danio rerio) model

The fine particulate matter (PM_2.5) in air pollution is a major public health concern and now known to contribute to severe diseases, therefore, a comprehensive understanding of PM_2.5-induced adverse effects in living organisms is needed urgently. This study was aimed to evaluate the toxicity of PM_2.5 on multi-organ systems in a zebrafish (Danio rerio) model. The embryonic toxicity induced by PM_2.5 was demonstrated by an increase in mortality and inhibition of hatching rate, in a dose- and time-dependent manner. PM_2.5 caused the pericardial edema, as well as reducing heart rate and cardiac output. The area of sub-intestinal vessels (SIVs) was significant reduced in Tg(fli-1:EGFP) transgenic zebrafish lines. Morphological defects and yolk sac retention were associated with hepatocyte injury. In addition, PM_2.5 disrupted the axonal integrity, altering of axon length and pattern in Tg(NBT:EGFP) transgenic lines. Genes involved in cardiac function (spaw, supt6h, cmlc1), angiogenesis (vegfr2a, vegfr2b), and neural function (gabrd, chrna3, npy8br) were markedly down-regulated; while genes linked to hepatic metabolism (cyp1a, cyp1b1, cyp1c1) were significantly up-regulated by PM_2.5. In summary, our data showed that PM_2.5 induced the cardiovascular toxicity, hepatotoxicity and neurotoxicity in zebrafish, suggested that PM_2.5 could cause multi-organ toxicity in aquatic organism.