Cr (VI)-induced ribosomal DNA copy number variation is associated with semen quality impairment: Evidence from human to animal study.

OBJECTIVES: This study aimed to analyze the possible role of rDNA copy number variation in the association between hexavalent chromium [Cr (VI)] exposure and semen quality in semen donors and further confirm this association in mice. METHODS: In this cross-sectional study, whole blood and semen samples were collected from 155 semen donors in the Zhejiang Human Sperm Bank from January 1st to April 31st, 2021. Adult C57BL/6 J male mice were treated with different doses of Cr (VI) (0, 10, or 15 mg/kg b.w./day). Semen quality, including semen volume, total spermatozoa count, sperm concentration, progressive motility, and total motility, were analyzed according to the WHO laboratory manual. Cr concentration was detected using inductively coupled plasma mass spectrometry. The rDNA copy number was measured using qPCR. RESULTS: In semen donors, whole blood Cr concentration was negatively associated with semen concentration and total sperm counts. Semen 5 S and 45 S rDNA copy numbers were negatively associated with whole blood Cr concentration and whole blood 5.8 S rDNA copy number was negatively associated with semen Cr concentration. In mice, Cr (VI) damaged testicular tissue, decreased semen quality, and caused rDNA copy number variation. Semen quality was related to the rDNA copy number in whole blood, testicular tissue, and semen samples in mice. CONCLUSION: Cr (VI) was associated with decreased semen quality in semen donors and mice. Our findings suggest an in-depth analysis of the role of the rDNA copy number variation in the Cr (VI)-induced impairment of semen quality.

Exosomal proteomics and cytokine analysis distinguish silicosis cases from controls.

Occupational silica exposure caused a serious disease burden of silicosis. There is currently a lack of sensitive and effective biomarkers for silicosis, and the pathogenesis of silicosis is unclear. Exosomes were significant in the pathogenesis of silicosis, and our study was carried out from exosomal proteomics and cytokine analysis. Firstly, the plasma levels of cytokines were detected using a Luminex multiplex assay, and the results indicated that the plasma levels of TNF-α, IL-6, CCL2, CXCL10, and PDGF-AB were significantly higher in silicosis patients than in silica-exposed workers and controls (p < 0.05). After correlation analysis, the plasma levels of cytokines were positively correlated with exosomal protein concentration. Secondly, data-independent acquisition (DIA) was performed on plasma-derived exosomes in the screening population, which identified 88, 151, 293, and 53 differentially expressed proteins (DEPs) in exposure/control, silicosis/control, silicosis/exposure, and silicosis stage Ⅲ/silicosis stage Ⅰ groups respectively. After parallel reaction monitoring (PRM) in an independent verification population, the results indicated that the changing trend of 15 DEPs was coincident in screening and verification results. The result of correlation analysis indicated that the plasma level of TNF-α was negatively correlated with the expression of exosomal DSP, KRT78, SERPINB12, and CALML5. The AUC of combined determination of TNF-α and CALML5 reached 0.900, with a sensitivity of 0.714 and a specificity of 0.933. Overall, our study revealed the exosomal proteomic profiling of silicosis patients, silica-exposed workers, and controls, indicating that exosomes were significant in the pathogenesis of silicosis. It also revealed that the combined of the plasma levels of cytokines and the expression of exosomal DEPs could increase determination efficiency. This study provided directions for the development of silicosis biomarkers and a scientific basis for the pathogenesis research of silicosis in the future.

Effects of the SEMA4B gene on hexavalent chromium [Cr(VI)]-induced malignant transformation of human bronchial epithelial cells.

Our previous study identified the potential of SEMA4B methylation level as a biomarker for hexavalent chromium [Cr(VI)] exposure. This study aimed to investigate the role of the SEMA4B gene in Cr(VI)-mediated malignant transformation of human bronchial epithelial (BEAS-2B) cells. In our population survey of workers, the geometric mean [95% confidence intervals (CIs)] of Cr in blood was 3.80 (0.42, 26.56) µg/L. Following treatment with various doses of Cr(VI), it was found that 0.5 µM had negligible effects on the cell viability of BEAS-2B cells. The expression of SEMA4B was observed to decrease in BEAS-2B cells after 7 days of treatment with 0.5 µM Cr(VI), and this downregulation continued with increasing passages of Cr(VI) treatment. Chronic exposure to 0.5 µM Cr(VI) enhanced the anchorage-independent growth ability of BEAS-2B cells. Furthermore, the use of a methylation inhibitor suppressed the Cr(VI)-mediated anchorage-independent growth in BEAS-2B cells. Considering that Cr levels exceeding 0.5 µM can be found in human blood due to occupational exposure, the results suggested a potential carcinogenic risk associated with occupational Cr(VI) exposure through the promotion of malignant transformation. The in vitro study further demonstrated that Cr(VI) exposure might inhibit the expression of the SEMA4B gene to promote the malignant transformation of BEAS-2B cells.

Genomic insights into the evolution of flavonoid biosynthesis and O-methyltransferase and glucosyltransferase in Chrysanthemum indicum.

Flavonoids are a class of secondary metabolites widely distributed in plants. Regiospecific modification by methylation and glycosylation determines flavonoid diversity. A rare flavone glycoside, diosmin (luteolin-4'-methoxyl-7-O-glucosyl-rhamnoside), occurs in Chrysanthemum indicum. How Chrysanthemum plants evolve new biosynthetic capacities remains elusive. Here, we assemble a 3.11-Gb high-quality C. indicum genome with a contig N50 value of 4.39 Mb and annotate 50,606 protein-coding genes. One (CiCOMT10) of the tandemly repeated O-methyltransferase genes undergoes neofunctionalization, preferentially transferring the methyl group to the 4'-hydroxyl group of luteolin with ortho-substituents to form diosmetin. In addition, CiUGT11 (UGT88B3) specifically glucosylates 7-OH group of diosmetin. Next, we construct a one-pot cascade biocatalyst system by combining CiCOMT10, CiUGT11, and our previously identified rhamnosyltransferase, effectively producing diosmin with over 80% conversion from luteolin. This study clarifies the role of transferases in flavonoid diversity and provides important gene elements essential for producing rare flavone.

Associations between maternal occupational exposures and pregnancy outcomes among Chinese nurses: a nationwide study.

BACKGROUND: Several studies have provided evidence about adverse pregnancy outcomes of nurses involved in occupational exposure. However, the pregnancy outcomes among nurses in middle-income countries are not well demonstrated. The main aim of this study is to present the prevalence and influencing factors of pregnancy outcomes among female nurses in China. METHODS: We included 2243 non-nurse health care workers, and 4230 nurses in this national cross-sectional study in China. Information on occupational exposures and pregnancy outcomes was collected using a face-to-face investigation. Odds ratios (ORs) were estimated through logistic regression. RESULTS: The proportion of threatened abortion, spontaneous abortion, and stillbirth of female nurses was 2.6%, 7%, and 2.1%, respectively. We found an increased risk of threatened abortion among nurses with overtime work (OR = 1.719, 95% CI 1.158-2.550). The risk of threatened abortion and spontaneous abortion was elevated among nurses handling disinfectant (OR = 2.293 and 1.63, respectively). We found a nearly twofold increased risk of premature birth (OR = 2.169, 95% CI 1.36-3.459) among nurses handling anti-cancer drugs. CONCLUSIONS: Our findings suggested that maternal occupational exposures might be associated with the risk of adverse pregnancy outcomes among female nurses in China. We recommend that policy-markers and hospital managers work together to reduce exposure to occupational hazards and improve pregnancy outcomes among female nurses.

Ribosomal DNA copy number alteration in blood sample from gastric cancer patients.

BACKGROUND: Ribosomal DNA (rDNA) is the most abundant and important housekeeping gene in the cell. It usually acted as DNA damage sensor in DNA damage reaction. Gastric cancer (GC) as a tumor with high morbidity and mortality, it is hard to diagnosis in an early stage. METHODS: In this study, we collected and test the copy number of rDNA in blood sample of 42 GC patients and 56 healthy controls (HC) to explore the relationship between rDNA and GC. Besides, we make a correlation between the copy number of rDNA and ten biomarkers (CYFR21-1, CA15-3, CA72-4, NSE, CEA, CA125, ProGRP, AFP, SCC, CA19-9). RESULTS: The copy number of 18 S, 5.8 S, 28 S rDNA in GC is less than HC and 5 S is more than HC in their blood sample. And the expression of H-cox-1 and ND1 in GC is higher than HC in blood sample. it shows the expression of CA15-3 is related to ND1 and H-cox-1. CONCLUSION: We found for the first time the changes of rDNA and mtDNA expression in the blood of patients with gastric cancer. All these finding suggests rDNA may have potential in diagnosing GC.

Hexavalent chromium [Cr(VI)]-induced ribosomal DNA copy number variation and DNA damage responses and their associations with nucleolar protein HRAS in humans and cells.

The carcinogenicity of hexavalent chromium [Cr(VI)] and its compounds has been widely recognized, yet the mechanism of genetic damage is still not fully understood. The ribosomal DNA (rDNA) copy number is recently considered a potential marker of cancer-associated stress. To investigate the roles of rDNA copy number variation (CNV) in DNA damage responses (DDRs) induced by Cr(VI) and the potential mechanism from nucleolar protein HRAS, a cross-sectional study in Cr(Ⅵ)-exposed workers and an in vitro experiment using HeLa cells were conducted. Our results showed increased levels of rDNA CNV, DDRs, and HRAS expression in Cr(VI)-exposed workers. Generalized linear regression analyses showed that Cr(VI) exposure was significantly positively associated with increased levels of rDNA CNV, DDRs, and HRAS expression in Cr(VI)-exposed workers. Moreover, there were pairwise associations between rDNA CNV, DDRs, and HRAS levels. Mediation analyses found that rDNA CNV significantly mediated the association between Cr(VI) exposure and DDRs. The in vitro experiments further confirmed that Cr(VI) treatment induced increased levels of rDNA CNV, DDRs, and HRAS expression in HeLa cells. Cr(VI)-induced rDNA CNV, ATM activation, and apoptosis damage were then strongly enhanced by HRAS depletion with siRNA in vitro, suggesting the important role of HRAS in CNV and DDRs caused by Cr(VI). The combined results of the human and cell line studies indicated that Cr(VI) exposure might enhance rDNA CNV by regulation of HRAS expression, which leads to Cr(VI)-induced genetic damage.

Terpenoid VOC profiles and functional characterization of terpene synthases in diploid and tetraploid cytotypes of Chrysanthemum indicum L.

Chrysanthemum indicum L. is a valuable medicinal plant with diploid and tetraploid forms that are widely distributed in central and southern China, and it contains abundant volatile organic compounds (VOCs). Despite the discovery of some terpene synthase (TPS) in C. indicum (i.e., CiTPS) in previous studies, many TPSs and their corresponding terpene biosynthesis pathways have yet to be discovered. In the present study, terpenoid VOCs in different tissues from two cytotypes of C. indicum were analyzed. We identified 52 types of terpenoid VOCs and systematically investigated the content and distribution of these compounds in various tissues. The two cytotypes of C. indicum exhibited different volatile terpenoid profiles. The content of monoterpenes and sesquiterpenes in the two cytotypes showed an opposite trend. In addition, four full-length candidate TPSs (named CiTPS5-8) were cloned from Ci-GD4x, and their homologous TPS genes were screened based on the genome data of Ci-HB2x. These eight TPSs displayed various tissue expression patterns and were discovered to produce 22 terpenoids, 5 of which are monoterpenes and 17 are sesquiterpenes. We further proposed corresponding terpene synthesis pathways, which can enable the establishment of an understanding of the volatile terpenoid profiles of C. indicum with different cytotypes. This knowledge may provide a further understanding of germplasm in C. indicum and may be useful for biotechnology applications of Chrysanthemum plants.

Mortality due to respiratory system disease and lung cancer among female workers exposed to chrysotile in Eastern China: A cross-sectional study.

Female workers in the asbestos processing industry of Eastern China are at high risk of developing multiple types of cancer, and more data are urgently needed to better understand and address this issue. Death certificate data were selected from an asbestos processing city in China from 2005 to 2006. Information was investigated using the relatives of those individuals who had died as sources of information. Individuals were classified into one of three asbestos exposure levels. Standardized mortality ratio and 95% confidence interval were calculated. A total of 2,964 individual deaths were identified from 2005 to 2006; of these, 21.4% were occupationally exposed to asbestos. The main cause of death was circulatory system diseases (21.2%). The proportion of individuals with respiratory system diseases increased by age among each exposure subgroup (P trend < 0.01). Among females, a significant trend was observed between increased asbestos exposure and mortality due to respiratory system diseases and lung cancer. Our study indicated that asbestos exposure was associated with excess mortality from lung cancer and respiratory diseases, particularly among female workers in an asbestos processing area in Eastern China.

Rhamnosyltransferases involved in the biosynthesis of flavone rutinosides in Chrysanthemum species.

Linarin (acacetin-7-O-rutinoside), isorhoifolin (apigenin-7-O-rutinoside), and diosmin (diosmetin-7-O-rutinoside) are chemically and structurally similar flavone rutinoside (FR) compounds found in Chrysanthemum L. (Anthemideae, Asteraceae) plants. However, their biosynthetic pathways remain largely unknown. In this study, we cloned and compared FRs and genes encoding rhamnosyltransferases (RhaTs) among eight accessions of Chrysanthemum polyploids. We also biochemically characterized RhaTs of Chrysanthemum plants and Citrus (Citrus sinensis and Citrus maxima). RhaTs from these two genera are substrate-promiscuous enzymes catalyzing the rhamnosylation of flavones, flavanones, and flavonols. Substrate specificity analysis revealed that Chrysanthemum 1,6RhaTs preferred flavone glucosides (e.g. acacetin-7-O-glucoside), whereas Cs1,6RhaT preferred flavanone glucosides. The nonsynonymous substitutions of RhaTs found in some cytotypes of diploids resulted in the loss of catalytic function. Phylogenetic analysis and specialized pathways responsible for the biosynthesis of major flavonoids in Chrysanthemum and Citrus revealed that rhamnosylation activity might share a common evolutionary origin. Overexpression of RhaT in hairy roots resulted in 13-, 2-, and 5-fold increases in linarin, isorhoifolin, and diosmin contents, respectively, indicating that RhaT is mainly involved in the biosynthesis of linarin. Our findings not only suggest that the substrate promiscuity of RhaTs contributes to the diversity of FRs in Chrysanthemum species but also shed light on the evolution of flavone and flavanone rutinosides in distant taxa.

Association of occupations with decreased semen quality in eastern China: a cross-sectional study of 12 301 semen donors.

OBJECTIVES: This study aims to examine the association between occupational factors and semen quality in semen donors in eastern China. METHODS: We recruited 12 301 semen donors from 2006 to 2020 as the studying population. A self-designed questionnaire was applied for collecting lifestyle and work style information. Semen samples were analysed according to WHO guidelines. A crude and adjusted linear regression model was used to analyse the association between occupational factors and semen quality. RESULTS: College students accounted for 36.2% of all semen donors. The majority (81.3%) of semen donors were between 18 year and 30 years. Soldiers or the police had the highest semen volume (the median value=3.8 mL), however, they had the lowest sperm concentration (53.6×106/ml) and sperm motility (45.5%). Workers in finance or insurance had an elevated risk of low semen volume, sperm concentration and total sperm count (OR=1.43, 1.57 and 1.98, respectively). Unemployed men had a high risk of low sperm concentration and low total sperm count (OR=1.84 and 1.58, respectively). Working in the information technology industry had a deleterious effect on the progressive motility of sperm (OR=1.27, 95% CI 1.03 to 1.57). CONCLUSION: Our study indicated that sedentary work style and intensive sports in certain professions might be associated with decreased semen quality. We reported evidence of becoming unemployed on the damage to semen quality. Hence, we advocate a healthy work style to improve semen quality in eastern China.

Ribosomal DNA copy number associated with blood metal levels in school-age children: A follow-up study on a municipal waste incinerator in Zhejiang, China.

To evaluate the body burdens of heavy metals and explore the impact of environmental metal exposure on ribosomal DNA (rDNA) or mitochondrial DNA (mtDNA) copy number (CN) variation in school-age children living near a municipal waste incinerator (MWI), we conducted a follow-up study in 2019. A total of 146 sixth-grade children from a primary school located 1.2 km away from the MWI were recruited for our study. Metals, including vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), stannum (Sn), stibium (Sb), thallium (Tl), and lead (Pb), were determined by an inductively coupled plasma mass spectrometer method. Real-time qPCR was used to measure the rDNA and mtDNA CN. The blood metal levels followed this order: Zn > Cu > Se > Pb > Mn > Sb > As > Ni > Cd > Co > Cr > Sn > V > Tl. Blood Cr level was significantly correlated with 18 S, 2.5 S, and 45 S CN (ß = -0.25, -0.22, -0.26, p < 0.05); Ni was correlated with 5 S (ß = -0.36, p < 0.01); Cu was correlated with 28 S, 18 S, and 5.8 S (ß = -0.24, -0.24, -0.23, p < 0.05); while Zn was correlated with 18 S, 5.8 S, and 45 S (ß = -0.28, -0.32, -0.26, p < 0.05). In conclusion, school-age children living near the MWI had lower blood metal levels compared to children recruited in 2013, while rDNA CN loss was found to be correlated to several heavy metals in these children.

Can Daytime Transcranial Direct Current Stimulation Treatment Change the Sleep Electroencephalogram Complexity of REM Sleep in Depressed Patients? A Double-Blinded, Randomized, Placebo-Controlled Trial.

Study Objectives: The purpose of this study was to determine the effects of daytime transcranial direct current stimulation (tDCS) on sleep electroencephalogram (EEG) in patients with depression. Methods: The study was a double-blinded, randomized, controlled clinical trial. A total of 37 patients diagnosed with a major depression were recruited; 19 patients (13 females and 6 males mean age 44.79 ± 15.25 years) received tDCS active stimulation and 18 patients (9 females and 9 males; mean age 43.61 ± 11.89 years) received sham stimulation. Ten sessions of daytime tDCS were administered with the anode over F3 and the cathode over F4. Each session delivered a 2 mA current for 30 min per 10 working days. Hamilton-24 and Montgomery scales were used to assess the severity of depression, and polysomnography (PSG) was used to assess sleep structure and EEG complexity. Eight intrinsic mode functions (IMFs) were computed from each EEG signal in a channel. The sample entropy of the cumulative sum of the IMFs were computed to acquire high-dimensional multi-scale complexity information of EEG signals. Results: The complexity of Rapid Eye Movement (REM) EEG signals significantly decreased intrinsic multi-scale entropy (iMSE) (1.732 ± 0.057 vs. 1.605 ± 0.046, P = 0.0004 in the case of the C4 channel, IMF 1:4 and scale 7) after tDCS active stimulation. The complexity of the REM EEG signals significantly increased iMSE (1.464 ± 0.101 vs. 1.611 ± 0.085, P = 0.001 for C4 channel, IMF 1:4 and scale 7) after tDCS sham stimulation. There was no significant difference in the Hamilton-24 (P = 0.988), Montgomery scale score (P = 0.726), and sleep structure (N1% P = 0.383; N2% P = 0.716; N3% P = 0.772) between the two groups after treatment. Conclusion: Daytime tDCS changed the complexity of sleep in the REM stage, and presented as decreased intrinsic multi-scale entropy, while no changes in sleep structure occurred. This finding indicated that daytime tDCS may be an effective method to improve sleep quality in depressed patients. Trial registration This trial has been registered at the ClinicalTrials.gov (protocol ID: TCHIRB-10409114, in progress).

Chromosome-level and haplotype-resolved genome provides insight into the tetraploid hybrid origin of patchouli.

Patchouli (Pogostemon cablin (Blanco) Benth.), a member of the Lamiaceae family, is an important aromatic plant that has been widely used in medicine and perfumery. Here, we report a 1.94 Gb chromosome-scale assembly of the patchouli genome (contig N50 = 7.97 Mb). The gene annotation reveals that tandem duplication of sesquiterpene biosynthetic genes may be a major contributor to the biosynthesis of patchouli bioactivity components. We further phase the genome into two distinct subgenomes (A and B), and identify a chromosome substitution event that have occurred between them. Further investigations show that a burst of universal LTR-RTs in the A subgenome lead to the divergence between two subgenomes. However, no significant subgenome dominance is detected. Finally, we track the evolutionary scenario of patchouli including whole genome tetraploidization, subgenome divergency, hybridization, and chromosome substitution, which are the key forces to determine the complexity of patchouli genome. Our work sheds light on the evolutionary history of patchouli and offers unprecedented genomic resources for fundamental patchouli research and elite germplasm development.

Isolation and characterization of AaZFP1, a C2H2 zinc finger protein that regulates the AaIPPI1 gene involved in artemisinin biosynthesis in Artemisia annua.

MAIN CONCLUSION: AaZFP1, a C2H2-type transcription factor, was found to bind the AGT-N1-10-AGT box of AaIPPI1pro and activate the expression of AaIPPI1 involved in artemisinin biosynthesis. Artemisinin, an endoperoxide sesquiterpene lactone, is a widely used antimalarial drug isolated from Artemisia annua L. Isopentenyl pyrophosphate isomerase (AaIPPI1) catalyzes the interconversion of isopentenyl diphosphate and dimethylallyl diphosphate and is the key gene involved in the biosynthesis of artemisinin. However, the AaIPPI1 gene regulation network remains largely unknown. Here, we isolated the AaIPPI1 promoter (AaIPPI1pro) and predicted that it contains cis-elements involved in stress responses, including the TGACG motif (a methyl jasmonate-responsive element), GARE motif (a gibberellin-responsive element), ABRE (an abscisic acid-responsive element), TC-rich repeats (a stress-responsive element), and the AGT-N1-10-AGT box, which is the binding site of Cys/His2 zinc finger protein (C2H2 ZFP). The C2H2 ZFP gene AaZFP1 was discovered by screening a cDNA library using AaIPPI1pro as bait in yeast. AaZFP1 contains two conserved C2H2 regions, a nuclear localization domain (B box), a Leu-rich domain (L box), and a conserved DLN sequence (DLN box) close to its C terminus. A subcellular localization assay indicated that AaZFP1 protein is localized in the nucleus and cytoplasm. An electrophoretic mobility shift assay demonstrated that AaZFP1 binds to the AGT-N1-10-AGT box of AaIPPI1pro. A dual-luciferase assay indicated that AaZFP1 enhanced the promoter activity of AaIPPI1 in vivo. Transient overexpression of AaZFP1 in A. annua increased the expression of AaIPPI1 and the content of artemisinin. Our data demonstrated that AaZFP1 functions as a transcriptional activator that regulates the expression of AaIPPI1 by directly binding to its promoter. The present study provides insights into the transcriptional regulation of genes involved in artemisinin biosynthesis in A. annua.

Serum apolipoprotein A-I depletion is causative to silica nanoparticles-induced cardiovascular damage.

The rapid development of nanotechnology has greatly benefited modern science and engineering and also led to an increased environmental exposure to nanoparticles (NPs). While recent research has established a correlation between the exposure of NPs and cardiovascular diseases, the intrinsic mechanisms of such a connection remain unclear. Inhaled NPs can penetrate the air-blood barrier from the lung to systemic circulation, thereby intruding the cardiovascular system and generating cardiotoxic effects. In this study, on-site cardiovascular damage was observed in mice upon respiratory exposure of silica nanoparticles (SiNPs), and the corresponding mechanism was investigated by focusing on the interaction of SiNPs and their encountered biomacromolecules en route. SiNPs were found to collect a significant amount of apolipoprotein A-I (Apo A-I) from the blood, in particular when the SiNPs were preadsorbed with pulmonary surfactants. While the adsorbed Apo A-I ameliorated the cytotoxic and proinflammatory effects of SiNPs, the protein was eliminated from the blood upon clearance of the NPs. However, supplementation of Apo A-I mimic peptide mitigated the atherosclerotic lesion induced by SiNPs. In addition, we found a further declined plasma Apo A-I level in clinical silicosis patients than coronary heart disease patients, suggesting clearance of SiNPs sequestered Apo A-I to compromise the coronal protein's regular biological functions. Together, this study has provided evidence that the protein corona of SiNPs acquired in the blood depletes Apo A-I, a biomarker for prediction of cardiovascular diseases, which gives rise to unexpected toxic effects of the nanoparticles.

miR221 regulates cell migration by targeting annexin a1 expression in human mesothelial MeT-5A cells neoplastic-like transformed by multi-walled carbon nanotube.

BACKGROUND: Multi-walled carbon nanotube (MWCNT) is one of the most widely used manufactured nanomaterials, however, its potential harmful effect on human health is of great concern. Previously we have shown the acute and chronic exposure to MWCNT induced different responses in human mesothelial MeT-5A cells. In the current study, MeT-5A cells were continuously subjected to MWCNT exposure at 10 µg/cm2 for 48 h per passage, up to a whole year, to further clarify the carcinogesis and its potential mechanisms of MWCNT. RESULTS: After one-year MWCNT treatment, MeT-5A cells exhibited neoplastic-like properties, including morphological changes, anchorage-independent growth, increased cell proliferation and cell migration. Further examination revealed the expression of microRNA 221 (miR221) was gradually decreased, while the annexin a1 expression was increased at both the mRNA and protein level during the exposure. Bioinformatic analysis indicated that annexin a1 is a target for miR221 regulation, and it was confirmed by transfecting cells with miR221 mimics, which resulted in the downregulation of annexin a1. Detailed analyses demonstrated miR221 was involved in the regulation of cell migration, e.g., downregulation of miR221 or overexpression of ANNEXIN A1, contributed to the increased cell migration. In contrast, overexpression of miR221 or downregulation of ANNEXIN A1 slowed cell migration. CONCLUSIONS: Taken together, these results point to a neoplastic-transforming property of MWCNT, and the miR221-annexin a1 axis is involved in the regulation of cell migration in the transformed cells.

Genome wide profiling of miRNAs relevant to the DNA damage response induced by hexavalent chromium exposure (DDR-related miRNAs in response to Cr (VI) exposure).

AIM: We aimed to explore the expression of miRNAs and their potential roles in the DNA damage response (DDR) induced by Cr (VI) exposure in human B lymphoblast cells (HMy2.CIR cells) and in a population of Cr (VI)-exposed humans. METHODS: Differentially expressed miRNAs were found by a combination of miRNA sequencing and RT-qPCR validation in HMy2.CIR cells treated with K2Cr2O7. Differentially expressed miRNAs related to DDR were selected for functional study. The expression levels of differential miRNAs were also investigated in chromate workers. RESULTS: A total of 214 differentially expressed miRNAs were identified by sequencing, and the expression of 5 miRNAs among 25 associated with DDR was found to be consistent between sequencing and validation studies.Functional studies showed that miR-148a-3p, miR-21-5p, and miR-424-3p might be related to Cr (VI)-induced cell apoptosis, and miR-221-3p might participate in Cr (VI)-induced DDR. We also found that the expression of miR-21-5p and miR-424-3p was upregulated in chromate workers. CONCLUSIONS: Cr (VI) exposure could significantly impact miRNAs expression in vitro and in chromate workers. Functional studies showed that miR-148a-3p, miR-21-5p and miR-221-3p might take a crucial role in the cellular DDR induced by Cr (VI) exposure.

Environmentally induced ribosomal DNA (rDNA) instability in human cells and populations exposed to hexavalent chromium [Cr (VI)].

Hexavalent Chromium [Cr (VI)] is an established toxicant, carcinogen, and a significant source of public health concern. The multicopy ribosomal DNA (rDNA) array is mechanistically linked to aging and cancer, is the most evolutionarily conserved segment of the human genome, and gives origin to nucleolus, a nuclear organelle where ribosomes are assembled. Here we show that exposure to Cr (VI) induces instability in the rDNA, triggering cycles of rapid, specific, and transient amplification and contraction of the array in human cells. The dynamic of environmentally responsive rDNA copy number (CN) amplification and contraction occurs at doses to which millions of individuals are regularly exposed. Finally, analyses of human populations occupationally exposed to Cr (VI) indicate that environmental exposure history and drinking habits but not age shape extensive naturally occurring rDNA copy number variation. Our observations identify a novel pathway of response to hexavalent chromium exposure and raise the prospect that a suite of environmental determinants of rDNA copy number remain to be discovered.

Exploration of identifying novel serum biomarkers for malignant mesothelioma using iTRAQ combined with 2D-LC-MS/MS.

Malignant mesothelioma (MM) is an aggressive cancer linked to asbestos exposure. Its poor prognosis makes early diagnosis extremely important, which would provide an opportunity for early treatment and potentially changing outcomes. This study aimed to explore the underlying mechanisms of MM and discover novel noninvasive biomarkers for the diagnosis of malignant mesothelioma. Using Isobaric tags for relative and absolute quantitation (iTRAQ) combined with two-dimensional liquid chromatography/tandem mass spectrometry (2D LC-MS/MS), a total of 145 differentially expressed serum proteins were identified between MM patients and healthy controls. The identified proteins were further analyzed by bioinformatics, out of which three candidate biomarkers (Filamin A (FLNA), Fibulin 1 (FBLN1) and Thrombospondin-1 (TSP-1)) were validated in large cohorts of patients with asbestos-related diseases including MM patients by ELISA assay. Receiver operating characteristic (ROC) curve analysis showed that serum FLNA, FBLN1 and TSP-1 had high diagnostic values in distinguishing MM patients from healthy controls, individuals with asbestos exposure (AE), and patients with pleural plaques (PP) or asbestosis. Meanwhile, serum FBLN1 and TSP-1 possessed good diagnostic values in distinguishing asbestosis patients from healthy controls and individuals with AE. The combination of FLNA, FBLN1, and TSP-1 proteins had higher sensitivity and specificity in discriminating patients with MM, PP and asbestosis. Our findings indicated that analysis of serum proteome using iTRAQ is a feasible strategy for biomarker discovery, and serum FLNA, FBLN1 and TSP-1 may be promising candidates for diagnosis of malignant mesothelioma and screening of at-risk individuals.