Folic acid targets splenic extramedullary hemopoiesis to attenuate carbon black-induced coagulation-thrombosis potential.

Due to its wide applications in tire and rubber products, carbon black (CB) implicates concerns on its safety during production, collection, and handling. Here we report that exposure CB, increases coagulation-thrombosis potential in a splenic extramedullary hemopoiesis (EMH)-dependent manner. Adult C57BL/6 mice are kept in whole-body inhalation chambers, and exposed to filtered room air (FRA) or CB for 28 consecutive days. CB exposure resulted in splenic EMH characterized with platelet precursor cells, megakaryocytes (MKs), hyperplasia and enhanced in vivo blood coagulation ability. Metabolomics analysis suggests significant enhance in PGE2 production but reduction in folic acid (FA) levels in murine serum following CB exposure. Mechanistically, activation of COX-dependent PGE2 production promotes IL-6 expression in splenic macrophages, which subsequently results in splenic EMH and increased platelet counts in circulation. Administration of FA protects the mice against CB-induced splenic EMH through inhibiting prostaglandin-endoperoxide synthase 2 (Ptgs2 or Cox2) and prostaglandin E synthase (Ptges) expression in splenic macrophages, eventually recover the coagulation capacity to normal level. The results strongly suggest the involvement of splenic EMH in response to CB exposure and subsequently increased coagulation-thrombosis potential. Supplementation with FA may be a candidate to prevent thrombosis potential attributable to CB exposure.

Up-regulation of miR-297 mediates aluminum oxide nanoparticle-induced lung inflammation through activation of Notch pathway.

Exposure to Aluminum oxide nanoparticles (Al2O3 NPs) has been associated with pulmonary inflammation in recent years; however, the underlying mechanism that causes adverse effects remains unclear. In the present study, we characterized microRNA (miRNA) expression profiling in human bronchial epithelial (HBE) cells exposed to Al2O3 NPs by miRNA microarray. Among the differentially expressed miRNAs, miR-297, a homologous miRNA in Homo sapiens and Mus musculus, was significantly up-regulated following exposure to Al2O3 NPs, compared with that in control. On combined bioinformatic analysis, proteomics analysis, and mRNA microarray, NF-κB-activating protein (NKAP) was found to be a target gene of miR-297 and it was significantly down-regulated in Al2O3 NPs-exposed HBE cells and murine lungs, compared with that in control. Meanwhile, inflammatory cytokines, including IL-1ß and TNF-α, were significantly increased in bronchoalveolar lavage fluid (BALF) from mice exposed to Al2O3 NPs. Then we set up a mouse model with intranasal instillation of antagomiR-297 to further confirm that inhibition of miR-297 expression can rescue pulmonary inflammation via Notch pathway suppression. Collectively, our findings suggested that up-regulation of miR-297 expression was an upstream driver of Notch pathway activation, which might be the underlying mechanism involved in lung inflammation induced by exposure to Al2O3 NPs.

Association between polymorphism in the promoter region of lncRNA GAS5 and the risk of colorectal cancer.

The growth arrest special 5 (GAS5), as a research hotspot of long noncoding RNAs (lncRNAs), has been reported to be associated with colorectal cancer (CRC). However, the association between polymorphisms in GAS5 and the risk of CRC was not clear. In the present study, a case-control study in 1078 CRC patients and 1175 matched healthy controls was performed to evaluate the association between the potential functional genetic variants in GAS5 and the risk of CRC. PCR-TaqMan, qPCR, dual-luciferase assay, electrophoretic mobility shift assay (EMSA), flow cytometry, migration and invasion assays were performed to evaluate the function of polymorphism. Results showed that subjects carrying the rs55829688 CT/TT genotypes had a significantly higher risk of CRC when compared with the CC genotype. Further qPCR assay confirmed that the CRC tissues with rs55829688 CT/TT genotypes had a higher GAS5 mRNA expression level. The dual-luciferase assay, qPCR and EMSA assay revealed that rs55829688 T>C polymorphism could decrease the expression level of GAS5 by impacting the binding ability of the transcription factor Yin Yang-1 (YY1) to the GAS5 promoter region. The expression of apoptosis-related proteins were detected by Western blot. Further, flow cytometry, migration, and invasion experiments showed that GAS5 repressed apoptosis and increased invasion and migration capability of CRC cells. Taken together, our findings provided evidence that the rs55829688 variant in the GAS5 promoter was associated with the risk of CRC and decreased expression of GAS5 by affecting the binding affinity of the transcription factors YY1 to GAS5.

Suppression of PTPN6 exacerbates aluminum oxide nanoparticle-induced COPD-like lesions in mice through activation of STAT pathway.

BACKGROUND: Inhaled nanoparticles can deposit in the deep lung where they interact with pulmonary cells. Despite numerous studies on pulmonary nanotoxicity, detailed molecular mechanisms of specific nanomaterial-induced lung injury have yet to be identified. RESULTS: Using whole-body dynamic inhalation model, we studied the interactions between aluminum oxide nanoparticles (Al2O3 NPs) and the pulmonary system in vivo. We found that seven-day-exposure to Al2O3 NPs resulted in emphysema and small airway remodeling in murine lungs, accompanied by enhanced inflammation and apoptosis. Al2O3 NPs exposure led to suppression of PTPN6 and phosphorylation of STAT3, culminating in increased expression of the apoptotic marker PDCD4. Rescue of PTPN6 expression or application of a STAT3 inhibitor, effectively protected murine lungs from inflammation and apoptosis, as well as, in part, from the induction of chronic obstructive pulmonary disease (COPD)-like effects. CONCLUSION: In summary, our studies show that inhibition of PTPN6 plays a critical role in Al2O3 NPs-induced COPD-like lesions.

Integrative functional transcriptomic analyses implicate specific molecular pathways in pulmonary toxicity from exposure to aluminum oxide nanoparticles.

Gene expression profiling has developed rapidly in recent years and it can predict and define mechanisms underlying chemical toxicity. Here, RNA microarray and computational technology were used to show that aluminum oxide nanoparticles (Al2O3 NPs) were capable of triggering up-regulation of genes related to the cell cycle and cell death in a human A549 lung adenocarcinoma cell line. Gene expression levels were validated in Al2O3 NPs exposed A549 cells and mice lung tissues, most of which showed consistent trends in regulation. Gene-transcription factor network analysis coupled with cell- and animal-based assays demonstrated that the genes encoding PTPN6, RTN4, BAX and IER play a role in the biological responses induced by the nanoparticle exposure, which caused cell death and cell cycle arrest in the G2/S phase. Further, down-regulated PTPN6 expression demonstrated a core role in the network, thus expression level of PTPN6 was rescued by plasmid transfection, which showed ameliorative effects of A549 cells against cell death and cell cycle arrest. These results demonstrate the feasibility of using gene expression profiling to predict cellular responses induced by nanomaterials, which could be used to develop a comprehensive knowledge of nanotoxicity.

An acetyl-L-carnitine switch on mitochondrial dysfunction and rescue in the metabolomics study on aluminum oxide nanoparticles.

BACKGROUND: Due to the wide application of engineered aluminum oxide nanoparticles and increased aluminum containing particulate matter suspending in air, exposure of human to nano-scale aluminum oxide nanoparticles (Al2O3 NPs) is becoming inevitable. METHODS: In the present study, RNA microarray coupled with metabolomics analysis were used to uncover mechanisms underlying cellular responses to Al2O3 NPs and imply the potential rescue. RESULTS: We found that Al2O3 NPs significantly triggered down-regulation of mitochondria-related genes located in complex I, IV and V, which were involved in oxidative phosphorylation and neural degeneration pathways, in human bronchial epithelial (HBE) cells. Subsequent cell- and animal- based assays confirmed that Al2O3 NPs caused mitochondria-dependent apoptosis and oxidative stress either in vitro or in vivo, which were consistent with the trends of gene regulation. To rescue the Al2O3 NPs induced mitochondria dysfunction, disruption of small molecular metabolites of HBE were profiled using metabolomics analysis, which facilitates identification of potential antagonizer or supplement against nanoparticle-involved damages. Supplementation of an antioxidant, acetyl-L-carnitine, completely or partially restored the Al2O3 NPs modulated gene expression levels in mitochondrial complex I, IV and V. It further reduced apoptosis and oxidative damages in both Al2O3 NPs treated HBE cells and animal lung tissues. CONCLUSION: Thus, our results demonstrate the potential mechanism of respiratory system damages induced by Al2O3 NPs. Meanwhile, based on the metabolomics profiling, application of acetyl-L-carnitine is suggested to ameliorate mitochondria dysfunction associated with Al2O3 NPs.

Sex-Dependent Depression-Like Behavior Induced by Respiratory Administration of Aluminum Oxide Nanoparticles.

Ultrafine aluminum oxide, which are abundant in ambient and involved occupational environments, are associated with neurobehavioral alterations. However, few studies have focused on the effect of sex differences following exposure to environmental Al2O3 ultrafine particles. In the present study, male and female mice were exposed to Al2O3 nanoparticles (NPs) through a respiratory route. Only the female mice showed depression-like behavior. Although no obvious pathological changes were observed in mice brain tissues, the neurotransmitter and voltage-gated ion channel related gene expression, as well as the small molecule metabolites in the cerebral cortex, were differentially modulated between male and female mice. Both mental disorder-involved gene expression levels and metabolomics analysis results strongly suggested that glutamate pathways were implicated in sex differentiation induced by Al2O3 NPs. Results demonstrated the potential mechanism of environmental ultrafine particle-induced depression-like behavior and the importance of sex dimorphism in the toxic research of environmental chemicals.