Exposure to Molybdate Results in Metabolic Disorder: An Integrated Study of the Urine Elementome and Serum Metabolome in Mice.

The increasing use of molybdate has raised concerns about its potential toxicity in humans. However, the potential toxicity of molybdate under the current level of human exposure remains largely unknown. Endogenous metabolic alterations that are caused in humans by environmental exposure to pollutants are associated with the occurrence and progression of many diseases. This study exposed eight-week-old male C57 mice to sodium molybdate at doses relevant to humans (0.01 and 1 mg/kg/day) for eight weeks. Inductively coupled plasma mass spectrometry (ICP-MS) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS) were utilized to assess changes in urine element levels and serum metabolites in mice, respectively. A total of 838 subjects from the NHANES 2017-2018 population database were also included in our study to verify the associations between molybdenum and cadmium found in mice. Analysis of the metabolome in mice revealed that four metabolites in blood serum exhibited significant changes, including 5-aminolevulinic acid, glycolic acid, l-acetylcarnitine, and 2,3-dihydroxypropyl octanoate. Analysis of the elementome revealed a significant increase in urine levels of cadmium after molybdate exposure in mice. Notably, molybdenum also showed a positive correlation with cadmium in humans from the NHANES database. Further analysis identified a positive correlation between cadmium and 2,3-dihydroxypropyl octanoate in mice. In conclusion, these findings suggest that molybdate exposure disrupted amino acid and lipid metabolism, which may be partially mediated by molybdate-altered cadmium levels. The integration of elementome and metabolome data provides sensitive information on molybdate-induced metabolic disorders and associated toxicities at levels relevant to human exposure.

Correlation between in vitro starch digestibility and starch structure/physicochemical properties in rice.

Natural resistant starch (RS) in rice provides human health benefits, and its concentration in rice is influenced by the structure and physicochemical properties of starch. The native starch structures and physicochemical properties of three rice varieties, QR, BR58, and BR50, and their relationships to in vitro digestibility were studied. The starch granules in all three varieties were irregular or polyhedral in shape. There were a few oval granules and a few pinhole structures in QR, no oval granules but a higher number of pinholes in BR58, and no oval granules and pinholes in BR50. QR is a low-amylose (13.8 %), low-RS (0.2 %) variety. BR58 is a low-amylose (15.3 %), high-RS (6.5 %) variety. BR50 is a high-amylose (26.7 %), high-RS (8.3 %) variety. All three starches exhibited typical A-type diffraction patterns. Starch molecular weight, chain length distribution, starch branching degree, pasting capabilities, and thermal properties differed considerably between the rice starches. The RS contents of the rice starch varieties were positively correlated with AAC, Mw/Mn, Mz/Mn, peak 3, B, PTime, and Tp and negatively correlated with Mn, peak 2, DB, PV, and BD, according to Pearson's correlation analysis. These findings may be helpful for the breeding and development of high-RS rice varieties.

Associations between the Maternal Exposome and Metabolome during Pregnancy.

BACKGROUND: Maternal exposure to environmental chemicals during pregnancy can influence various maternal and offspring health parameters. Modification of maternal metabolism by environmental exposure may be an important pathway for these impacts. However, there is limited evidence regarding exposure to a wide array of chemicals and the metabolome during pregnancy. OBJECTIVES: We investigated the relationship between the urinary exposome and metabolome during pregnancy. METHODS: Urine samples were collected in the first and third trimesters from 1,024 pregnant women recruited in prenatal clinics in Jiangsu Province, China. The exposome was analyzed using the first trimester sample with ultra-high performance liquid chromatography-high resolution accurate mass spectrometry (UHPLC-HRMS) and inductively coupled plasma mass spectrometry. The metabolome was analyzed using the third trimester sample with UHPLC-HRMS. We evaluated associations between each of 106 exposures in the first trimester with 139 metabolites in the third trimester. RESULTS: We identified 1,245 significant associations (p<3.39×10-6, Bonferroni correction) between chemical exposures and maternal metabolism during pregnancy. Among elements, the largest number of the significant metabolic associations were observed for magnesium, and among organic compounds, for 4-tert-octylphenol. We used exposome-metabolome associations to explore mechanisms underlying published associations between prenatal chemical exposures and offspring health outcomes. This integration of the literature with our results suggests that reported associations between 10 analytes and birth weight, gestational age, fat deposition, neurobehavioral development, immunological disorders, and hypertension may be partially mediated by metabolites associated with these exposures. DISCUSSION: This high-dimensional analysis of the urinary exposome and metabolome identified many associations between chemical exposures and maternal metabolism during pregnancy. Integration of these associations with the literature on health outcomes of exposure suggests that environmental modulation of the maternal metabolome may play a role in the association between prenatal exposure on pregnancy and child health outcomes. https://doi.org/10.1289/EHP9745.

A metabolomic study on the effect of prenatal exposure to Benzophenone-3 on spontaneous fetal loss in mice.

Benzophenone-3 (BP-3) is widely used in a variety of cosmetics and is prevalent in drinking water or food, and women were under notable high exposure burden of BP-3. Reports show the associations between prenatal exposure to BP-3 and the risk of fetal loss, but its underlying mechanism remains largely unknown. Pregnant ICR mice were gavaged with BP-3 from gestational day (GD) 0 to GD 6 at doses of 0.1, 10 and 1000 mg/kg/day. The samples were collected on GD 12. Ultra-performance liquid chromatography coupled with mass spectrometry-based metabolomics was used to detect metabolome changes in fetal mice, the uterus and the placenta to identify the underlying mechanism. The results showed that the body weight and relative organ weights of the liver, brain and uterus of pregnant mice were not significantly changed between the control group and the treatment group. BP-3 increased fetal loss, and induced placental thrombosis and tissue necrosis with enhancement of platelet aggregation. Metabolomic analysis revealed that fructose and mannose metabolism, the TCA cycle, arginine and proline metabolism in the fetus, arginine and proline metabolism and biotin metabolism in the uterus, and arginine biosynthesis and pyrimidine metabolism in the placenta were the key changed pathways involved in the above changes. Our study indicates that exposure to BP-3 can induce placental thrombosis and fetal loss via the disruption of maternal and fetal metabolism in mice, providing novel insights into the influence of BP-3 toxicity on the female reproductive system.

The profiling of elements and pesticides in surface water in Nanjing, China with global comparisons.

The study on high-throughput determination covering various kinds of elements and pesticides in surface water is rarely reported. The surface water samples were collected from the Yangtze River, the Qinhuai River and the Xuanwu Lake in Nanjing which is a large and populous city in eastern China, and elementome (47 elements) and pesticide exposome (60 pesticides) were profiled, which were characterized by univariate and multivariate statistical analysis, literature comparison, and risk assessment. A total of 47 elements and 47 pesticides were detectable. By combining the results of univariate and multivariate statistical analysis, we consistently found that the levels of elements in the Qinhuai River were relatively higher than those in the Yangtze River and the Xuanwu Lake, mainly including rare earth elements and macroelements. The concentrations of isoprocarb, profenofos and simazine in the Yangtze River were relatively higher than those in the Qinhuai River and the Xuanwu Lake. Based on literature search and our data, the results about global element and pesticide concentrations in surface water were summarized. The surface water in Nanjing showed notably higher aluminum level when compared to the level around the world. The risk assessment suggested that arsenic posed a considerable carcinogenic risk. This study provided a large volume of first-hand information about the profiles of elements and pesticides in surface water, which can be used for warning of surface water pollution and preventing potential hazardous effect on public health.

Characterization of Metabolic Patterns in Mouse Oocytes during Meiotic Maturation.

Well-balanced and timed metabolism is essential for making a high-quality egg. However, the metabolic framework that supports oocyte development remains poorly understood. Here, we obtained the temporal metabolome profiles of mouse oocytes during in vivo maturation by isolating large number of cells at key stages. In parallel, quantitative proteomic analyses were conducted to bolster the metabolomic data, synergistically depicting the global metabolic patterns in oocytes. In particular, we discovered the metabolic features during meiotic maturation, such as the fall in polyunsaturated fatty acids (PUFAs) level and the active serine-glycine-one-carbon (SGOC) pathway. Using functional approaches, we further identified the key targets mediating the action of PUFA arachidonic acid (ARA) on meiotic maturation and demonstrated the control of epigenetic marks in maturing oocytes by SGOC network. Our data serve as a broad resource on the dynamics occurring in metabolome and proteome during oocyte maturation.

The relationship between semen factors and unexplained recurrent spontaneous abortion.

BACKGROUND: The male factor may contribute to unexplained recurrent spontaneous abortion (URSA). The relationship between semen factors and URSA is largely unknown. The analysis of metabolomics which is broadly acknowledged as the omics closest to the phenotype is suitable for providing assistance in the semen parameters analysis. METHODS: We conducted a study including couples with URSA and controls which was next combined with a meta-analysis, and finally the study included 2352 subjects on semen parameters and URSA. Metabolomics analysis was conducted to detect semen metabolic factors related to URSA in total of 106 samples including seminal plasma and sperm cells. RESULTS: The URSA group had significantly lower total sperm count, sperm concentration, motility and normal morphology percentage. Meta-analysis next showed consistent findings. Metabolomics revealed that 4 metabolites and one pathway and 8 metabolites and one pathway were significantly associated with URSA in sperm and seminal plasma, respectively. The combination of ascorbic acid and guanine in seminal plasma and hexadecanedioic acid and pyroglutamic acid in sperm showed ability for URSA prediction. CONCLUSION: We provided novel insights into semen indices in relation to URSA. Lower sperm number and quality might increase the risk of URSA, and oxidative stress and hormone metabolism in sperm as well as nucleic acid synthesis and oxidative stress in seminal plasma were related to URSA.

A metabolomic study on the association of exposure to heavy metals in the first trimester with primary tooth eruption.

BACKGROUND: The influence of prenatal heavy metals exposure on primary tooth eruption in humans is rarely reported. AIM: Based on the cohort study design, we investigated the association of exposure to 12 heavy metals in the first trimester with primary tooth eruption, and the maternal metabolisms in the first trimester which might be related to the above relationship. METHODS: Maternal urine samples were collected in their first trimester, and 12 metals (Ti, V, Fe, Co, Cu, As, Se, Cd, Sn, Hg, Tl, U) were measured using the inductively coupled plasma mass spectrometry method. The maternal metabolome in the first trimester was analyzed by ultrahigh performance liquid chromatography coupled mass spectrometry based metabolomics using urine samples. The infant's first tooth eruption time and number of teeth at age one were recorded by oral examination and questionnaire. RESULTS: No significant associations were observed between heavy metals exposure in the first trimester and primary tooth eruption, except for Co. The level of Co was positively associated with time of infant's first tooth eruption, and was negatively associated with the number of teeth at age one. Based on metabolomic profiling, glycine was revealed as the key mediating metabolite, which showed negative correlation with Co and opposite effect of Co in the primary tooth eruption. CONCLUSIONS: Prenatal Co exposure in the first trimester might delay the primary tooth eruption in children through the decreased glycine-disrupted dentin formation, providing the first evidence and novel insights into the control of prenatal heavy metals exposure for ensuring normal (timely) primary tooth eruption.

Metabolomics study and meta-analysis on the association between maternal pesticide exposome and birth outcomes.

BACKGROUND: Pregnant women are exposed to a number of pesticides which are widely used in China. Their potential risks on reproduction and infants are still unknown. OBJECTIVE: We aimed to investigate whether infant's birth weight and length of gestation were associated with levels of various pesticides in maternal blood based on Nanjing Medical University (NMU) affiliated hospitals data and meta-analysis, and also to explore the possible intermediate metabolomics pathways. METHODS: Eligible subjects (n = 102) were included in this study from the affiliated hospitals of NMU. Gas chromatography tandem mass spectrometry (GC/MS) and Q-Exactive mass spectrometer (QE) were used to detect 37 pesticides (9 organophosphorus pesticides, 7 organochlorine pesticides, 5 carbamate pesticides, and 16 others) and 161 metabolites (53 in animo acid metabolism 47 in lipid metabolism, 18 in carbohydrate metabolism, 14 in nucleotide metabolism and 29 in other metabolisms) in maternal blood, respectively. Multi-linear regression and Bayesian kernel machine regression (BKMR) were performed to identify the association of single/mixed pesticide exposure in maternal blood with birth weight and length of gestation. Moreover, we conducted a meta-analysis including additional 2497 subjects to evaluate whether exposure to key pesticide, ß-hexachlorocyclohexane (ß-HCH) was associated with decreased birth weight globally. Mediation analysis was used to explore the metabolic alteration mediating the association between key pesticide exposure and birth outcomes. RESULTS: We found that decreased birth weight was significantly associated with increasing levels of mecarbam and ß-HCH. We did not find any association between length of gestation and these pesticides. Among pesticides with detection rate more than 50%, BKMR analysis found an overall negative association of mixed pesticides exposure with birth weight, and verified that ß-HCH was the key pesticide for such effect. Meta-analysis revealed a significantly negative association between exposure to ß-HCH and birth weight. Metabolomics identified three metabolites and five metabolites as significant mediators for the effect of mecarbam and ß-HCH, respectively, among which glyceraldehyde and its related glycerolipid metabolism and thyroxine and its related thyroid hormone metabolism were found to be the mostly enriched mediating metabolic pathway. CONCLUSIONS: Based on the comprehensive pesticide exposome and metabolome wide associational study combined with meta-analysis, we found that prenatal exposure to ß-HCH and mecarbam decreased birth weight via disrupting thyroid hormone metabolism and glyceraldehyde metabolism, providing new insights into the toxic effects of exposure to pesticides on birth outcomes.

Metabolomic profiling identifies novel biomarkers and mechanisms in human bladder cancer treated with submucosal injection of gemcitabine.

Bladder cancer (BCa) is a common urinary tract malignancy with frequent recurrences after initial resection. Submucosal injection of gemcitabine prior to transurethral resection of bladder tumor (TURBT) may prevent recurrence of urothelial cancer. However, the underlying mechanism remains unknown. In the present study, ultra­performance liquid chromatography Q­Exactive mass spectrometry was used to profile tissue metabolites from 12 BCa patients. The 48 samples included pre­ and post­gemcitabine treatment BCa tissues, as well as adjacent normal tissues. Principal component analysis (PCA) revealed that the metabolic profiles of pre­gemcitabine BCa tissues differed significantly from those of pre­gemcitabine normal tissues. A total of 34 significantly altered metabolites were further analyzed. Pathway analysis using MetaboAnalyst identified three metabolic pathways closely associated with BCa, including glutathione, purine and thiamine metabolism, while glutathione metabolism was also identified by the enrichment analysis using MetaboAnalyst. In search of the possible targets of gemcitabine, metabolite profiles were compared between the pre­gemcitabine normal and post­gemcitabine BCa tissues. Among the 34 metabolites associated with BCa, the levels of bilirubin and retinal recovered in BCa tissues treated with gemcitabine. When comparing normal bladder tissues with and without gemcitabine treatment, among the 34 metabolites associated with BCa, it was observed that histamine change may be associated with the prevention of relapse, whereas thiamine change may be involved in possible side effects. Therefore, by employing a hypothesis­free tissue­based metabolomics study, the present study investigated the metabolic signatures of BCa and found that bilirubin and retinal may be involved in the mechanism underlying the biomolecular action of submucosal injection of gemcitabine in urothelial BCa.

Up regulation of miR-96-5p is responsible for TiO2 NPs induced invasion dysfunction of human trophoblastic cells via disturbing Ezrin mediated cytoskeletons arrangement.

Titanium dioxide nanoparticles (TiO2 NPs) are used extensively in our daily lives, and their toxic effects on the placenta have been reported. Animal studies indicated that placental development is impaired after maternal exposure of TiO2 NPs, but the underlying mechanisms remain largely unknown. In the present study, we used a human trophoblast-derived cell, HTR8-SVneo, to determine how TiO2 NPs affected placental functions, and found out potential reversal targets. TEM was employed for TiO2 NPs morphology observation and uptake assessment. RT-PCR was used to detect the expression of both mRNA and miRNA, and western blotting was used for protein examination. Cell invasion ability was evaluated by Transwell assay, and cytoskeletons were observed by immunofluorescence combined with confocal microscope examination. We found that TiO2 NPs disrupted cytoskeletons and impaired cell invasion ability. Further investigations showed that TiO2 NPs increased the expression of a microRNA (miR-96-5p), which targeted and down-regulated the translation of EZR mRNA, a gene that encodes ezrin protein, and affected the cell cytoskeletons and ultimately cell invasion ability. When the expression of miR-96-5p was down-regulated, the expression level of ezrin protein was also reversed, and cell invasion ability was partially restored. Collectively, we determined how miR-96-5p mediates TiO2 NP-induced placental dysfunction, and provided a potential rescue target for future therapy.

OsABCG15 encodes a membrane protein that plays an important role in anther cuticle and pollen exine formation in rice.

KEY MESSAGE: An ABC transporter gene ( OsABCG15 ) was proven to be involved in pollen development in rice. The corresponding protein was localized on the plasma membrane using subcellular localization. Wax, cutin, and sporopollenin are important for normal development of the anther cuticle and pollen exine, respectively. Their lipid soluble precursors, which are produced in the tapetum, are then secreted and transferred to the anther and microspore surface for polymerization. However, little is known about the mechanisms underlying the transport of these precursors. Here, we identified and characterized a member of the G subfamily of ATP-binding cassette (ABC) transporters, OsABCG15, which is required for the secretion of these lipid-soluble precursors in rice. Using map-based cloning, we found a spontaneous A-to-C transition in the fourth exon of OsABCG15 that caused an amino acid substitution of Thr-to-Pro in the predicted ATP-binding domain of the protein sequence. This osabcg15 mutant failed to produce any viable pollen and was completely male sterile. Histological analysis indicated that osabcg15 exhibited an undeveloped anther cuticle, enlarged middle layer, abnormal Ubisch body development, tapetum degeneration with a falling apart style, and collapsed pollen grains without detectable exine. OsABCG15 was expressed preferentially in the tapetum, and the fused GFP-OsABCG15 protein was localized to the plasma membrane. Our results suggested that OsABCG15 played an essential role in the formation of the rice anther cuticle and pollen exine. This role may include the secretion of the lipid precursors from the tapetum to facilitate the transfer of precursors to the surface of the anther epidermis as well as to microspores.