Changes in miR-222 expression, DNA repair capacity, and MDM2-p53 axis in association with low-dose benzene genotoxicity and hematotoxicity.

Mechanisms for hematotoxicity and health effects from exposure to low doses of benzene (BZ) remain to be identified. To address the information gap, our investigation was focused onto using appropriate populations and cell cultures to investigate novel BZ-induced effects such as disruption of DNA repair capacity (DRC). From our study, abnormal miRNAs were identified and validated using lymphocytes from 56 BZ-poisoned workers and 53 controls. In addition, 173 current BZ-exposed workers and 58 controls were investigated for key miRNA expression using RT-PCR and for cellular DRC using a challenge assay. Subsequently, the observed activities in lymphocytes were verified using human HL-60 (p53 null) and TK6 (p53 wild-type) cells via 1,4-benzoquinone (1,4-BQ) treatment and miR-222 interferences. The targeting of MDM2 by miR-222 was validated using a luciferase reporter. Our results indicate induction of genotoxicity in lymphocytes from workers with low exposure doses to BZ. In addition, miR-222 expression was up-regulated among both BZ-poisoned and BZ-exposed workers together with inverse association with DRC. Our in vitro validation studies using both cell lines indicate that 1,4-BQ exposure increased expression of miR-222 and Comet tail length but decreased DRC. Loss of miR-222 reduced DNA damage, but induced S-phase arrest and apoptosis. However, silencing of MDM2 failed to activate p53 in TK6 cells. In conclusion, our in vivo observations were confirmed by in vitro studies showing that BZ/1,4-BQ exposures caused genotoxicity and high expression of miR-222 which obstructed expression of the MDM2-p53 axis that led to failed activation of p53, abnormal DRC and serious biological consequences.

Aberrant lncRNA Profiles Are Associated With Chronic Benzene Poisoning and Acute Myelocytic Leukemia.

OBJECTIVE: This study investigates the mechanisms of benzene hematotoxicity. METHODS: We used microarray to detect expression profiles of long non-coding RNAs (lncRNAs) and mRNAs in peripheral lymphocytes from chronic benzene poisoning, acute myelocytic leukemia, and healthy controls. The lncRNAs and mRNAs were validated using real-time quantitative PCR (RT-qPCR). Cytokinesis-block micronucleus assay was used to analyze chromosomal aberration. RESULTS: We found 173 upregulated and 258 downregulated lncRNAs, and 695 upregulated and 804 downregulated mRNAs. The lncRNA CUST_40243 and mRNA PDGFC and CDKN1A associated with chronic benzene poisoning. Relevant inflammatory response, hematopoietic cell lineage, and cell cycle may be important pathways for the sifted lncRNAs and mRNAs. Furthermore, micronuclei frequency was significantly higher in off-post chronic benzene poisoning patients. CONCLUSIONS: Chromosomal aberration induced by benzene exposure is irreversible. The lncRNA CUST_40243 and mRNA PDGFC and CDKN1A are related to chronic benzene poisoning.

Promoter hypermethylation in CSF3R induces peripheral neutrophil reduction in benzene-exposure poisoning.

Benzene is a global pollutant and has been established to cause leukemia. To better understand the role of DNA methylation in benzene toxicity, peripheral blood mononuclear cells were collected from six benzene-poisoning patients and six matched controls for genome-wide DNA methylation screening by Illumina Infinium Methylation 450 BeadChip. The Gene Chip Human Gene 2.0 ST Array (Affymetrix) was used to analyze global mRNA expression. Compared with the corresponding sites of controls, 442 sites in patients were hypermethylated, corresponding to 253 genes, and 237 sites were hypomethylated, corresponding to 130 genes. The promoter methylation and mRNA expression of CSF3R, CREB5, and F2R were selected for verification by bisulfite sequencing and real-time PCR in a larger data set with 21 cases and 23 controls. The results indicated that promoter methylation of CSF3R (p = .005) and F2R (p = .015) was significantly higher in cases than in controls. Correlation analysis showed that the promoter methylation of CSF3R (p < .001) and F2R (p < .001) was highly correlated with its mRNA expression. In the poisoning cases, neutrophil percentage was significantly different among the high, middle, and low CSF3R-methylation groups (p = .002). In particular, the neutrophil percentage in the high CSF3R-methylation group (48.10 ± 9.63%) was significantly lower than that in the low CSF3R-methylation group (59.30 ± 6.26%) (p = .012). The correlation coefficient between promoter methylation in CSF3R and the neutrophil percentage was -0.445 (p = .020) in cases and - 0.398 (p = .060) in controls. These results imply that hypermethylation occurs in the CSF3R promoter due to benzene exposure and is significantly associated with a reduction in neutrophils.

[The clinical features of indium-related lung diseases].

OBJECTIVE: To discuss the clinical features of Indium-related lung diseases. METHODS: We searched database of Chinese and Pubmed, Embase, Web of Science to collect research data of indium-related lung diseases from Jan. 1998 to Aprl. 2014. Case reports, exposure histories and lab results were analysed and summarized. RESULTS: 1998 to Mar 2010, ten cases of indium-related lung diseases were published. Seven cases of interstitial pneumonia were reported in Japan, two cases of pulmonary alveolar proteinosis (PAP) were reported in the USA and one case of PAP reported in China. Chest computer tomography (CT) showed diffuse or local ground glass appearance (GGA) in 8 cases, 3 of which also showed centrilobular nodules; Pulmonary function test were normal only in one out of 8 cases. Cholesterol clefts were found in 4 cases of interstitial pneumonia. 3 cases died among 6 cases who were followed-up. CONCLUSIONS: Occupational exposure to indium compounds are contributory to different pulmonary diseases, which are composed of interstitial pneumonia and pulmonary alveolar proteinosis. The relationships between In-C, In-S and these pulmonary diseases are unclear.

Cardiopulmonary exercise capacity and ventilation effectiveness in patients after clinical cure of acute irritant gas poisoning.

The aim of this study is to assess the medium to long-term effect of acute irritant gas poisoning on cardiopulmonary exercise function in patients after clinical cure. Fourteen patients after an average of 18.5 months of clinical cure of acute irritant gas poisoning were recruited, and 14 healthy individuals were selected as control. All subjects were examined by resting pulmonary function testing (RPFT), cardiopulmonary exercise testing (CPET), and arterial blood gas (ABG) analysis. No statistically significant differences were found between poisoning and control groups for baseline parameters (age, height, and weight) or ABG values (pH, PaO2, PaCO2, and SaO2) (P > 0.05). For most RPFT parameters, including FEV1/FVC, FEV1, FEV1%pred, RV/TLC, DLCO%, and FVC%, no statistically significant differences were observed between poisoning and control groups (P > 0.05). However, MVV% was significantly lower in poisoning group compared with healthy individuals (P < 0.05). Statistically significant differences were observed for some CPET parameters, including peak VO2, peak VO2/kg, peak VE, and lowest VE/VCO2 (P < 0.05), and peak load, V D/V T, and peak PETCO2 (P < 0.01) between the two groups. However, there were no statistically significant differences in peak VO2%pred or peak O2 pulse between poisoning and control groups (P > 0.05). Compared with controls, patients with acute irritant gas poisoning had decreased cardiopulmonary exercise capacity and ventilation effectiveness after clinical cure.