Deciphering the impact of greenhouse pesticides on hepatic metabolism profile: Toxicity experiments on HepG2 cells using chlorpyrifos and emamectin benzoate.

Epidemiological evidence on the health effects of pesticide exposure among greenhouse workers is limited, and the mechanisms are lacking. Building upon our team's previous population study, we selected two pesticides, CPF and EB, with high detection rates, based on the theoretical foundation that the liver serves as a detoxifying organ, we constructed a toxicity model using HepG2 cells to investigate the impact of individual or combined pesticide exposure on the hepatic metabolism profile, attempting to identify targeted biomarkers. Our results showed that CPF and EB could significantly affect the survival rate of HepG2 cells and disrupt their metabolic profile. There were 117 metabolites interfered by CPF exposure, which mainly affected ABC transporter, biosynthesis of amino acids, center carbon metabolism in cancer, fatty acid biosynthesis and other pathways, 95 metabolites interfered by EB exposure, which mainly affected center carbon metabolism in cancer, HIF-1 signaling pathway, valine, leucine and isoleucine biosynthesis, fatty acid biosynthesis and other pathways. The cross analysis and further biological experiments confirmed that CPF and EB pesticide exposure may affect the HIF-1 signaling pathway and valine, leucine and isoleucine biosynthesis in HepG2 cells, providing reliable experimental evidence for the prevention and treatment of liver damage in greenhouse workers.

High glucose enhances the activation of NLRP3 inflammasome by ambient fine particulate matter in alveolar macrophages.

BACKGROUND: Epidemiological studies have demonstrated that individuals with preexisting conditions, including diabetes mellitus (DM), are more susceptible to air pollution. However, the underlying mechanisms remain unclear. In this study, we proposed that a high glucose setting enhances ambient fine particulate matter (PM2.5)-induced macrophage activation and secretion of the proinflammatory cytokine, IL-1ß, through activation of the NLRP3 inflammasome, altering the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs). RESULTS: Exposure of mouse alveolar macrophages to non-cytotoxic doses of PM2.5 led to upregulation of IL-1ß, activation of the NLRP3 inflammasome, increased nuclear translocation of the transcription factor NF-κB, increased generation of reactive oxygen species (ROS), and increased expression and enzymatic activity of MMP-9; these effects were enhanced when cells were pretreated with high glucose. However, pretreatment in a high glucose setting alone did not induce significant changes. ROS generation following PM2.5 exposure was abolished when cells were pretreated with ROS scavengers such as Trolox and superoxide dismutase (SOD), or with an NADPH oxidase inhibitor, DPI. Pretreatment of cells with DPI attenuated the effects of a high glucose setting on PM2.5-induced upregulation of IL-1ß, activation of the NLRP3 inflammasome, and nuclear translocation of NF-κB. In addition, enhancement of PM2.5-induced expression and enzymatic activity of MMP-9 following high glucose pretreatment was not observed in primary alveolar macrophages obtained from NLRP3 or IL-1R1 knockout (KO) mice, where pro-IL-1ß cannot be cleaved to IL-1ß or cells are insensitive to IL-1ß, respectively. CONCLUSIONS: This study demonstrated that exposure of mouse alveolar macrophages to PM2.5 in a high glucose setting enhanced PM2.5-induced production of IL-1ß through activation of the NLRP3 inflammasome and nuclear translocation of NF-κB due to PM2.5-induced oxidative stress, leading to MMP-9 upregulation. The key role of NADPH oxidase in PM2.5-induced ROS generation and activation of the IL-1ß secretion pathway and the importance of IL-1ß secretion and signaling in PM2.5-induced increases in MMP-9 enzymatic activity were also demonstrated. This study provides a further understanding of the potential mechanisms underlying the susceptibility of individuals with DM to air pollution and suggests potential therapeutic targets.

MMP-3-mediated cleavage of OPN is involved in copper oxide nanoparticle-induced activation of fibroblasts.

BACKGROUND: Copper oxide nanoparticles (Nano-CuO) are one of the most produced and used nanomaterials. Previous studies have shown that exposure to Nano-CuO caused acute lung injury, inflammation, and fibrosis. However, the mechanisms underlying Nano-CuO-induced lung fibrosis are still unclear. Here, we hypothesized that exposure of human lung epithelial cells and macrophages to Nano-CuO would upregulate MMP-3, which cleaved osteopontin (OPN), resulting in fibroblast activation and lung fibrosis. METHODS: A triple co-culture model was established to explore the mechanisms underlying Nano-CuO-induced fibroblast activation. Cytotoxicity of Nano-CuO on BEAS-2B, U937* macrophages, and MRC-5 fibroblasts were determined by alamarBlue and MTS assays. The expression or activity of MMP-3, OPN, and fibrosis-associated proteins was determined by Western blot or zymography assay. Migration of MRC-5 fibroblasts was evaluated by wound healing assay. MMP-3 siRNA and an RGD-containing peptide, GRGDSP, were used to explore the role of MMP-3 and cleaved OPN in fibroblast activation. RESULTS: Exposure to non-cytotoxic doses of Nano-CuO (0.5 and 1 µg/mL) caused increased expression and activity of MMP-3 in the conditioned media of BEAS-2B and U937* cells, but not MRC-5 fibroblasts. Nano-CuO exposure also caused increased production of cleaved OPN fragments, which was abolished by MMP-3 siRNA transfection. Conditioned media from Nano-CuO-exposed BEAS-2B, U937*, or the co-culture of BEAS-2B and U937* caused activation of unexposed MRC-5 fibroblasts. However, direct exposure of MRC-5 fibroblasts to Nano-CuO did not induce their activation. In a triple co-culture system, exposure of BEAS-2B and U937* cells to Nano-CuO caused activation of unexposed MRC-5 fibroblasts, while transfection of MMP-3 siRNA in BEAS-2B and U937* cells significantly inhibited the activation and migration of MRC-5 fibroblasts. In addition, pretreatment with GRGDSP peptide inhibited Nano-CuO-induced activation and migration of MRC-5 fibroblasts in the triple co-culture system. CONCLUSIONS: Our results demonstrated that Nano-CuO exposure caused increased production of MMP-3 from lung epithelial BEAS-2B cells and U937* macrophages, which cleaved OPN, resulting in the activation of lung fibroblasts MRC-5. These results suggest that MMP-3-cleaved OPN may play a key role in Nano-CuO-induced activation of lung fibroblasts. More investigations are needed to confirm whether these effects are due to the nanoparticles themselves and/or Cu ions.

Nickel nanoparticles induce autophagy and apoptosis via HIF-1α/mTOR signaling in human bronchial epithelial cells.

With the rapid development of nanotechnology, the potential adverse health effects of nanoparticles have been caught more attention and become global concerns. However, the underlying mechanisms in metal nanoparticle-induced toxic effects are still largely obscure. In this study, we investigated whether exposure to nickel nanoparticles (Nano-Ni) and titanium dioxide nanoparticles (Nano-TiO2) would alter autophagy and apoptosis levels in normal human bronchial epithelial BEAS-2B cells and the underlying mechanisms involved in this process. Our results showed that the expressions of autophagy- and apoptosis-associated proteins were dysregulated in cells exposed to Nano-Ni. However, exposure to the same doses of Nano-TiO2 had no significant effects on these proteins. In addition, exposure to Nano-Ni, but not Nano-TiO2, led to nuclear accumulation of HIF-1α and decreased phosphorylation of mTOR in BEAS-2B cells. Inhibition of HIF-1α by CAY10585 abolished Nano-Ni-induced decreased phosphorylation of mTOR, while activation of mTOR by MHY1485 did not affect Nano-Ni-induced nuclear accumulation of HIF-1α. Furthermore, both HIF-1α inhibition and mTOR activation abolished Nano-Ni-induced autophagy but enhanced Nano-Ni-induced apoptosis. Blockage of autophagic flux by Bafilomycin A1 exacerbated Nano-Ni-induced apoptosis, while activation of autophagy by Rapamycin effectively rescued Nano-Ni-induced apoptosis. In conclusion, our results demonstrated that Nano-Ni exposure caused increased levels of autophagy and apoptosis via the HIF-1α/mTOR signaling axis. Nano-Ni-induced autophagy has a protective role against Nano-Ni-induced apoptosis. These findings provide us with further insight into Nano-Ni-induced toxicity.

Study on the influence mechanism of students' behavior of participation in industrial colleges-Analysis framework based on theory of planned behavior.

As a new organizational form for the coordinated development of education and industry, industrial college is an important carrier for application-oriented colleges and universities to implement application-oriented talent training. Based on Theory of Planned Behavior (TPB) as a theoretical framework, this research constructs a model of the influencing factors of college students' participating in industrial colleges from five criteria: behavioral attitudes, subjective norms, perceived behavioral control, behavioral intentions and situational factors. In this study, participants (N = 541) have completed a questionnaire to assess their behavior of participation in the industrial colleges by using the structural equation model (SEM). It turns out that perceived needs, mandatory norms, exemplary norms, and self-efficacy significantly positively affect college students' intention to participate in industrial colleges. Behavior intention and self-efficacy significantly positively affect college students' participation in industrial colleges. Behavior intentions act as a complete mediator between perceived needs and behavior, as well as between exemplary norms and behavior. Behavioral intentions partially mediate between mandatory norms and behavior, as well as between self-efficacy and behavior. In addition, school support plays a significant positive moderating role in college students' intention and behavior of participating in industrial colleges. These findings not only expand the relevant literature on college students' learning behavior, but also provide useful enlightenment for college education managers on how to stimulate college students' endogenous motivation to participate in industrial colleges.

Nickel nanoparticles induce epithelial-mesenchymal transition in human bronchial epithelial cells via the HIF-1α/HDAC3 pathway.

We and others have previously demonstrated that exposure to nickel nanoparticles (Nano-Ni) caused fibrogenic and carcinogenic effects; however, the underlying mechanisms are still not fully understood. This study aimed to investigate the effects of Nano-Ni on epithelial-mesenchymal transition (EMT) in human bronchial epithelial cells (BEAS-2B) and its underlying mechanisms since EMT is involved in both cancer pathogenesis and tissue fibrosis. Our results showed that exposure to Nano-Ni, compared to the control Nano-TiO2, caused a remarkable decrease in the expression of E-cadherin and an increase in the expression of vimentin and α-SMA, indicating an inducible role of Nano-Ni in EMT development in human bronchial epithelial cells. HIF-1α nuclear accumulation, HDAC3 upregulation, and decreased histone acetylation were also observed in the cells exposed to Nano-Ni, but not in those exposed to Nano-TiO2. Pretreatment of the cells with a specific HIF-1α inhibitor, CAY10585, or HIF-1α-specific siRNA transfection prior to Nano-Ni exposure resulted in the restoration of E-cadherin and abolished Nano-Ni-induced upregulation of vimentin and α-SMA, suggesting a crucial role of HIF-1α in Nano-Ni-induced EMT development. CAY10585 pretreatment also attenuated the HDAC3 upregulation and increased histone acetylation. Inhibition of HDAC3 with specific siRNA significantly restrained Nano-Ni-induced reduction in histone acetylation and restored EMT-related protein expression to near control levels. In summary, our findings suggest that exposure to Nano-Ni promotes the development of EMT in human bronchial epithelial cells by decreasing histone acetylation through HIF-1α-mediated HDAC3 upregulation. Our findings may provide information for further understanding of the molecular mechanisms of Nano-Ni-induced fibrosis and carcinogenesis.

Distinct Role of Surface Hydroxyls in Single-Atom Pt1/CeO2 Catalyst for Room-Temperature Formaldehyde Oxidation: Acid-Base Versus Redox.

The development of highly efficient catalysts for room-temperature formaldehyde (HCHO) oxidation is of great interest for indoor air purification. In this work, it was found that the single-atom Pt1/CeO2 catalyst exhibits a remarkable activity with complete removal of HCHO even at 288 K. Combining density functional theory calculations and in situ DRIFTS experiments, it was revealed that the active OlatticeH site generated on CeO2 in the vicinity of Pt2+ via steam treatment plays a key role in the oxidation of HCHO to formate and its further oxidation to CO2. Such involvement of hydroxyls is fundamentally different from that of cofeeding water which dissociates on metal oxide and catalyzes the acid-base-related chemistry. This study provides an important implication for the design and synthesis of supported Pt catalysts with atom efficiency for a very important practical application-room-temperature HCHO oxidation.

A protective role of autophagy in fine airborne particulate matter-induced apoptosis in LN-229 cells.

Air pollution is a public health threat and global epidemiological studies have shown that ambient air pollutants are closely related to various poor health conditions, including neurodegenerative diseases. Here, we evaluated the toxic effects and the underlying mechanisms of fine airborne particulate matter (PM2.5) on human glioblastoma LN-229 cells. Our results showed that exposure of LN-229 cells to PM2.5 (≥ 200 µg/mL) significantly reduced cell viability. PM2.5 exposure increased autophagy, apoptosis, and ROS production in the cells. Pre-treatment with a ROS scavenger, catalase, or depletion of mtDNA (ρ0 cells) abolished PM2.5-induced autophagy and apoptosis. PM2.5 exposure also activated MAPK signals in cells, which were blocked by catalase pre-treatment or mtDNA depletion. Furthermore, inhibition of JNK, but not ERK1/2 or p38, attenuated PM2.5-induced autophagy and apoptosis in cells. Finally, suppression of autophagy with Bafilomycin A1 or Beclin 1 siRNA exacerbated PM2.5-induced apoptosis, indicating a protective role of autophagy against PM2.5-induced apoptosis. Our results demonstrated that exposure of LN-229 cells to PM2.5 caused autophagy and apoptosis through PM2.5-induced ROS generation, mainly by mitochondria, and JNK activation. Autophagy may have a transient protective response in PM2.5-induced apoptosis. These findings have important implications for understanding the potential neurotoxicity of PM2.5.

Research on the Influence Mechanism of Enterprises' Participation in School Enterprise Cooperation Based on the Analysis Framework of Theory of Planned Behavior.

School enterprise cooperation, as the basic school running form of applied undergraduate education, is an important way to cultivate applied talents. However, at present, the lack of motivation for enterprises to participate in school enterprise cooperation and the resulting problem of "school hot and enterprise cold" seriously limit the talent training quality in China's application-oriented universities. There is an urgent need to explore the influencing factors and mechanisms of enterprises' participation in school enterprise cooperation to improve the training quality of applied talents. Taking Ajzen (2002) Theory of Planned Behavior as the theoretical framework, this study constructs the influencing factor model of enterprise participation in school enterprise cooperation from four aspects, namely, behavior attitude, subjective norms, perceived behavior control, and behavior intention. In this study, participants (N = 250) completed a questionnaire assessing their participation in school enterprise cooperation, which was analyzed by a structural equation model. The results show that the behavior attitude and perceived behavior control of enterprises have a significant positive impact on their intention to participate in school enterprise cooperation and then have a significant positive impact on the school enterprise cooperation behavior of enterprises. The behavior intention and perceived behavior control of enterprises have a significant positive impact on their participation in school enterprise cooperation. The policy environment has a significant regulatory effect on the relationship between the intention and behavior of enterprises' participation in school enterprise cooperation. Therefore, from the perspective of enhancing the intention of enterprises to cooperate, colleges and universities should establish the awareness of win-win cooperation and meet the interest demands of enterprises in school enterprise cooperation in order to improve the behavior attitude and intention of enterprises. From the perspective of the formation conditions of school enterprise cooperation, with the help of industry associations, an information service platform for school enterprise cooperation should be built in order to eliminate the information islands between enterprises and universities. From the perspective of the needs of school enterprise cooperation environment, government departments should strengthen the policy support for school enterprise cooperation in order to eliminate the worries of enterprises' participation in school enterprise cooperation.

Nickel nanoparticle-induced cell transformation: involvement of DNA damage and DNA repair defect through HIF-1α/miR-210/Rad52 pathway.

BACKGROUND: Nickel nanoparticles (Nano-Ni) are increasingly used in industry and biomedicine with the development of nanotechnology. However, the genotoxic and carcinogenic effects of Nano-Ni and the underlying mechanisms are still unclear. METHODS: At first, dose-response (0, 10, 20, and 30 µg/mL) and time-response (0, 3, 6, 12, and 24 h) studies were performed in immortalized normal human bronchial epithelial cells BEAS-2B to observe the effects of Nano-Ni on DNA damage response (DDR)-associated proteins and the HIF-1α/miR-210/Rad52 pathway by real-time PCR or Western blot. Then, a Hsp90 inhibitor (1 µM of 17-AAG, an indirect HIF-1α inhibitor), HIF-1α knock-out (KO) cells, and a miR-210 inhibitor (20 nM) were used to determine whether Nano-Ni-induced Rad52 down-regulation was through HIF-1α nuclear accumulation and miR-210 up-regulation. In the long-term experiments, cells were treated with 0.25 and 0.5 µg/mL of Nano-Ni for 21 cycles (~ 150 days), and the level of anchorage-independent growth was determined by plating the cells in soft agar. Transduction of lentiviral particles containing human Rad52 ORF into BEAS-2B cells was used to observe the role of Rad52 in Nano-Ni-induced cell transformation. Nano-Ni-induced DNA damage and dysregulation of HIF-1α/miR-210/Rad52 pathway were also investigated in vivo by intratracheal instillation of 50 µg per mouse of Nano-Ni. gpt delta transgenic mice were used to analyze mutant frequency and mutation spectrum in mouse lungs after Nano-Ni exposure. RESULTS: Nano-Ni exposure caused DNA damage at both in vitro and in vivo settings, which was reflected by increased phosphorylation of DDR-associated proteins such as ATM at Ser1981, p53 at Ser15, and H2AX. Nano-Ni exposure also induced HIF-1α nuclear accumulation, miR-210 up-regulation, and down-regulation of homologous recombination repair (HRR) gene Rad52. Inhibition of or knocking-out HIF-1α or miR-210 ameliorated Nano-Ni-induced Rad52 down-regulation. Long-term low-dose Nano-Ni exposure led to cell malignant transformation, and augmentation of Rad52 expression significantly reduced Nano-Ni-induced cell transformation. In addition, increased immunostaining of cell proliferation markers, Ki-67 and PCNA, was observed in bronchiolar epithelial cells and hyperplastic pneumocytes in mouse lungs at day 7 and day 42 after Nano-Ni exposure. Finally, using gpt delta transgenic mice revealed that Nano-Ni exposure did not cause increased gpt mutant frequency and certain DNA mutations, such as base substitution and small base insertions/deletions, are not the main types of Nano-Ni-induced DNA damage. CONCLUSIONS: This study unraveled the mechanisms underlying Nano-Ni-induced cell malignant transformation; the combined effects of Nano-Ni-induced DNA damage and DNA repair defects through HIF-1α/miR-210/Rad52 pathway likely contribute to Nano-Ni-induced genomic instability and ultimately cell transformation. Our findings will provide information to further elucidate the molecular mechanisms of Nano-Ni-induced genotoxicity and carcinogenicity.

[Application of copy number variation sequencing combined with short tandem repeat in analysis of abortion and prenatal diagnosis].

OBJECTIVE: To explore the cause of abortion and strategy of prenatal diagnosis for pregnant women with high risk for chromosomal abnormalities by using copy number variation sequencing (CNV-seq) and short tandem repeats (STR) analysis. METHODS: A total of 36 samples were collected, including amniotic fluid, abortion tissue, whole blood, chorionic villi and umbilical cord blood. CNV-seq and STR analysis were carried out to detect microdeletions, microduplications, chromosomal aneuploidies, mosaicisms and triploidies. RESULTS: Among all samples, 1 was detected with 4p15.1p16.3 and 14q11.1q22.1 duplication, 1 was detected with 19p13.3 deletion, 8 were detected with chromosomal aneuploidies, 4 were detected with mosaicisms, two were detected with triploidies. No definite pathogenic CNVs were detected in 20 samples, which yielded a positive detection rate of 44.44%. CONCLUSION: As a high-throughput detection method, CNV-seq has the advantages of rapidity, simplicity and high accuracy. It may suit prenatal diagnosis and analysis of abortion factors in combination with STR analysis.

Effects of metal nanoparticles on tight junction-associated proteins via HIF-1α/miR-29b/MMPs pathway in human epidermal keratinocytes.

BACKGROUND: The increasing use of metal nanoparticles in industry and biomedicine raises the risk for unintentional exposure. The ability of metal nanoparticles to penetrate the skin ranges from stopping at the stratum corneum to passing below the dermis and entering the systemic circulation. Despite the potential health risks associated with skin exposure to metal nanoparticles, the mechanisms underlying the toxicity of metal nanoparticles on skin keratinocytes remain unclear. In this study, we proposed that exposure of human epidermal keratinocytes (HaCaT) to metal nanoparticles, such as nickel nanoparticles, dysregulates tight-junction associated proteins by interacting with the HIF-1α/miR-29b/MMPs axis. METHODS: We performed dose-response and time-response studies in HaCaT cells to observe the effects of Nano-Ni or Nano-TiO2 on the expression and activity of MMP-2 and MMP-9, and on the expression of tight junction-associated proteins, TIMP-1, TIMP-2, miR-29b, and HIF-1α. In the dose-response studies, cells were exposed to 0, 10, or 20 µg/mL of Nano-Ni or Nano-TiO2 for 24 h. In the time-response studies, cells were exposed to 20 µg/mL of Nano-Ni for 12, 24, 48, or 72 h. After treatment, cells were collected to either assess the expression of mRNAs and miR-29b by real-time PCR or to determine the expression of tight junction-associated proteins and HIF-1α nuclear accumulation by Western blot and/or immunofluorescent staining; the conditioned media were collected to evaluate the MMP-2 and MMP-9 activities by gelatin zymography assay. To further investigate the mechanisms underlying Nano-Ni-induced dysregulation of tight junction-associated proteins, we employed a HIF-1α inhibitor, CAY10585, to perturb HIF-1α accumulation in one experiment, and transfected a miR-29b-3p mimic into the HaCaT cells before Nano-Ni exposure in another experiment. Cells and conditioned media were collected, and the expression and activities of MMPs and the expression of tight junction-associated proteins were determined as described above. RESULTS: Exposure of HaCaT cells to Nano-Ni resulted in a dose-dependent increase in the expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 and the activities of MMP-2 and MMP-9. However, exposure of cells to Nano-TiO2 did not cause these effects. Nano-Ni caused a dose-dependent decrease in the expression of miR-29b and tight junction-associated proteins, such as ZO-1, occludin, and claudin-1, while Nano-TiO2 did not. Nano-Ni also caused a dose-dependent increase in HIF-1α nuclear accumulation. The time-response studies showed that Nano-Ni caused significantly increased expressions of MMP-2 at 24 h, MMP-9 at 12, 24, and 48 h, TIMP-1 from 24 to 72 h, and TIMP-2 from 12 to 72 h post-exposure. The expression of miR-29b and tight junction-associated proteins such as ZO-1, occludin, and claudin-1 decreased as early as 12 h post-exposure, and their levels declined gradually over time. Pretreatment of cells with a HIF-1α inhibitor, CAY10585, abolished Nano-Ni-induced miR-29b down-regulation and MMP-2/9 up-regulation. Introduction of a miR-29b-3p mimic into HaCaT cells by transfection before Nano-Ni exposure ameliorated Nano-Ni-induced increased expression and activity of MMP-2 and MMP-9 and restored Nano-Ni-induced down-regulation of tight junction-associated proteins. CONCLUSION: Our study herein demonstrated that exposure of human epidermal keratinocytes to Nano-Ni caused increased HIF-1α nuclear accumulation and increased transcription and activity of MMP-2 and MMP-9 and down-regulation of miR-29b and tight junction-associated proteins. Nano-Ni-induced miR-29b down-regulation was through Nano-Ni-induced HIF-1α nuclear accumulation. Restoration of miR-29b level by miR-29b-3p mimic transfection abolished Nano-Ni-induced MMP-2 and MMP-9 activation and down-regulation of tight junction-associated proteins. In summary, our results demonstrated that Nano-Ni-induced dysregulation of tight junction-associated proteins in skin keratinocytes was via HIF-1α/miR-29b/MMPs pathway.

MMP-3 activation is involved in copper oxide nanoparticle-induced epithelial-mesenchymal transition in human lung epithelial cells.

Copper oxide nanoparticles (Nano-CuO) are widely used in medical and industrial fields and our daily necessities. However, the biosafety assessment of Nano-CuO is far behind their rapid development. Here, we investigated the adverse effects of Nano-CuO on normal human bronchial epithelial BEAS-2B cells, especially determined whether Nano-CuO exposure would cause dysregulation of MMP-3, an important mediator in pulmonary fibrosis, and its potential role in epithelial-mesenchymal transition (EMT). Our results showed that exposure to Nano-CuO, but not Nano-TiO2, caused increased ROS generation, MAPKs activation, and MMP-3 upregulation. Nano-CuO-induced ROS generation was not observed in mitochondrial DNA-depleted BEAS-2B ρ0 cells, indicating that mitochondria may be the main source of Nano-CuO-induced ROS generation. Pretreatment of the cells with ROS scavengers or inhibitors or depleting mitochondrial DNA significantly attenuated Nano-CuO-induced MAPKs activation and MMP-3 upregulation, and pretreatment of cells with MAPKs inhibitors abolished Nano-CuO-induced MMP-3 upregulation, suggesting Nano-CuO-induced MMP-3 upregulation is through Nano-CuO-induced ROS generation and MAPKs activation. In addition, exposure of the cells to Nano-CuO for 48 h resulted in decreased E-cadherin expression and increased expression of vimentin, α-SMA, and fibronectin, which was ameliorated by MMP-3 siRNA transfection, suggesting an important role of MMP-3 in Nano-CuO-induced EMT. Taken together, our study demonstrated that Nano-CuO exposure caused mitochondrial ROS generation, MAPKs activation, and MMP-3 upregulation. Nano-CuO exposure also caused cells to undergo EMT, which was through Nano-CuO-induced dysregulation of ROS/MAPKs/MMP-3 pathway. Our findings will provide further understanding of the potential mechanisms involved in metal nanoparticle-induced various toxic effects including EMT and pulmonary fibrosis.

Risk Assessment of Nanoparticle Exposure in a Calcium Carbonate Manufacturing Workshop with Six Control Banding Tools.

With wide production and use, nanometer calcium carbonate (nano-CaCO3) has attracted much more concerns due to its potential inhalation toxicity in the occupational setting. It is of great significance to protect exposure workers by scientifically measuring the concentration of aerosol nano-CaCO3 particles, evaluating the risk levels at the production sites and accordingly providing suggestions of improvement. In this study, the aerosol particle concentrations of six operating procedures in a nano-CaCO3 production workshop were determined, including digesting, carbonization, modification, pressure filtration, drying and packaging. The relevant occupational exposure risk was assessed by six control banding (CB) tools, CB Nanotool, Stoffenmanager Nano, Nanosafer, the Guidance on Working Safely with Nanomaterials and Nanoproducts (GWSNN), French Agency for Food, Environmental and Occupational Health and Safety method (ANSES) and Precautionary Matrix for Synthetic Nanomaterials (Precautionary Matrix). It was found that there are quite high concentrations of airborne nanoparticles released from the nano-CaCO3 production procedures in this workshop. Most aerosol particles were agglomerated with the sizes of primary particles about 100 nm. The number concentration of aerosol particles at packaging site is 407000 particles/cm³ in size range of 0.02-1.0 µm, which is 10 times higher than the aerosol particle concentration at the digestion site. Furthermore, there is a significant correlation between the metrics of number and surface area concentrations detected in this workshop. The risk assessment results indicate that this workshop has medium or high exposure risks of the occupational nanoparticle exposure. Detailed engineering control or personal occupational protection should be implemented to protect the occupational health in this workshop. Similar and comparable judgment results were obtained, although the input parameters for six risk assessment CB tools are different. It was found that Stoffenmanager nano and Nanosafer are more suitable for the risk assessment of this workshop comparing to the other four tools. It is recommended a wide applications of risk assessment tools to various nanotechnology related occupational settings for controlling the occupational health risks.

The Overview of Methods of Nanoparticle Exposure Assessment.

Nanotechnology is now widely used in industry as well as consumer products, such as electrical devices, cosmetics, medicine, and household appliances. In the life cycle of the nano-products, including production, use, and disposal, nanoparticles may be released to the environment. However, there is no current consensus on the best method for evaluating and characterizing nanoparticle exposure. Therefore, this chapter focuses on the nanoparticle exposure assessment methods and sampling techniques.

[An analysis of characteristics of exposure to nanoparticles in a workplace manufacturing iron oxide nanoparticles].

OBJECTIVE: To investigate the characteristics of exposure to iron oxide nanoparticles in workplace. METHODS: The real-time particle number (NC), surface area (SAC), and mass (MC) concentrations of nanoparticles were measured in various locations of a selected workplace manufacturing iron oxide nanoparticles. The collected particles were analyzed for morphology and elemental composition. RESULTS: The average NCs and SACs in milling site (16,566 pt/cm3, 106.082 µm2/cm3), packaging site (12,386 pt/cm3, 89.861 µm2/cm3), shipping site (13,808 pt/cm3, 102.071 µm2/cm3), and product storage room (17,192 pt/cm, 115.044 µm2/cm3) of the yellow powder (α-Fe2O3 . nH2O) were all significantly higher than the workplace background concentrations (11,420 pt/cm3, 85.026 µm2/cm3) (all P<0.05). The NC was highly correlated with the SAC (r= 0.784), while both NC and SAC were loosely correlated with the MC (r1=0.323, r2=0.331). Scanning electron microscopy revealed a spindle-like shape of the iron oxide nanoparticle; the chemical composition of the collected particles contained 19.33 weight percent iron (Fe). CONCLUSION: The milling site and product storage room of the yellow powder are exposed to a higher concentration of nanoparticles, which are mainly composed of iron oxide nanoparticles. The NC is highly correlated with the SAC.

Exposure characteristics of ferric oxide nanoparticles released during activities for manufacturing ferric oxide nanomaterials.

The exposure characteristics of Fe2O3 nanoparticles (NPs) released in a factory were investigated, as exposure data on this type of NP is absent. The nature of the particles was identified in terms of their concentrations [i.e. number concentration (NC(20-1000 nm)), mass concentration (MC(100-1000 nm)), surface area concentration (SAC(10-1000 nm))], size distribution, morphology and elemental composition. The relationships between different exposure metrics were determined through analyses of exposure ranking (ER), concentration ratios (CR), correlation coefficients and shapes of the particle concentration curves. Work activities such as powder screening, material feeding and packaging generated higher levels of NPs as compared to those of background particles (p < 0.01). The airborne Fe2O3 NPs exhibited a unimodal size distribution and a spindle-like morphology and consisted predominantly of the elements O and Fe. Periodic and activity-related characteristics were noticed in the temporal variations in NC(20-1000 nm) and SAC(10-1000 nm). The modal size of the Fe2O3 NPs remained relatively constant (ranging from 10 to 15 nm) during the working periods. The ER, CR values and the shapes of NC(20-1000 nm) and SAC(10-1000 nm) curves were similar; however, these were significantly different from those for MC(100-1000 nm). There was a high correlation between NC(20-1000 nm) and SAC(10-1000 nm), and relatively lower correlations between the two and MC(100-1000 nm). These findings suggest that the work activities during the manufacturing processes generated high levels of primary Fe2O3 NPs. The particle concentrations exhibited periodicity and were activity dependent. The number and SACs were found to be much more relevant metrics for characterizing NPs than was the mass concentration.

Construction of the tricyclic core of steenkrotin-type diterpenoids via intramolecular [3 + 2] cycloaddition.

A concise and diastereoselective route to the angularly fused [5-6-7] tricyclic carbon framework of the steenkrotin-type diterpenoids was reported. The key features of the strategy are based on an intramolecular nitrile oxide/alkene [3 + 2] cycloaddition and a regio-selective aldol/dehydration sequence.

Diastereoselective total synthesis of salvileucalin C.

A concise and efficient approach for the diastereoselective total synthesis of salvileucalin C, as well as their biosynthetically related diterpenoids salvileucalin D, salvipuberulin, isosalvipuberulin, and dugesin B, has been reported for the first time. The key features of the strategy are based on a Beckwith-Dowd ring expansion, a tandem diastereoselective Stille coupling/debromination/desilylation/lactonization reaction, and a photoinduced electrocyclic ring contraction.

Ax21-triggered immunity plays a significant role in rice defense against Xanthomonas oryzae pv. oryzicola.

XA21, as a pattern recognition receptor in rice, senses the quorum-sensing (QS) signal molecule Ax21 secreted by Xanthomonas oryzae pv. oryzae (Xoo) and mediates hypersensitive response-like immunity against the pathogen. However, for the infection of another pathovar, X. o. pv. oryzicola (Xoc), relatively weak defense responses are observed in XA21-containing rice cultivars. In the present study, we demonstrated that the Xoc Δax21 mutant caused more severe disease symptoms than the wild type in XA21 rice cv. IRBB21, but not in non-Xa21 rice cv. Taipei 309. The substance(s) secreted by the wild-type Xoc strain, but not those by the ax21 mutant triggered host immunity against Xoo PXO99 Δax21 in Xa21 rice. Immunoblot analysis corroborated that Xoc, like Xoo, synthesizes and secretes Ax21. Furthermore, the membrane fusion protein RaxA was demonstrated to be required, but the ATP-binding cassette transporter RaxB was dispensable for Ax21 secretion in Xoc. In addition, we demonstrated that Ax21 functions as a QS signal molecule that regulates biofilm formation in Xoc. However, Ax21 signaling is dispensable for bacterial motility, the production of extracellular polysaccharide and protease secretion in Xoc. Interestingly, the two-component system RaxR/H was involved in the regulation of bacterial motility and the regulation was likely independent on Ax21 signaling in Xoc. Taken together, the results indicated that Ax21 secreted by Xoc might induce plant immunity that plays a significant role in rice defense against the pathogen infection.