A study of low-molecular-weight organic acid urinary profiles in prostate cancer by a new liquid chromatography-tandem mass spectrometry method

Arsenic activated GLUT1-mTORC1/HIF-1α-PKM2 positive feedback networks promote proliferation and migration of bladder epithelial cells

Arsenic (As) is recognized as a potent environmental contaminant associated with bladder carcinogenesis. However, its molecular mechanism remains unclear. Metabolic reprogramming is one of the hallmarks of cancer and is as a central feature of malignancy. Here, we performed the study of cross-talk between the mammalian target of rapamycin complex 1 (mTORC1)/ Hypoxia-inducible factor 1 alpha (HIF-1α) pathway and aerobic glycolysis in promoting the proliferation and migration of bladder epithelial cells treated by arsenic in vivo and in vitro. We demonstrated that arsenite promoted N-methyl-N-nitrosourea (MNU)-induced tumor formation in the bladder of rats and the malignant behavior of human ureteral epithelial (SV-HUC-1) cell. We found that arsenite positively regulated the mTORC1/HIF-1α pathway through glucose transporter protein 1 (GLUT1), which involved in the malignant progression of bladder epithelial cells relying on glycolysis. In addition, pyruvate kinase M2 (PKM2) increased by arsenite reduced the protein expressions of succinate dehydrogenase (SDH) and fumarate hydratase (FH), leading to the accumulation of tumor metabolites of succinate and fumarate. Moreover, heat shock protein (HSP)90, functioning as a chaperone protein, stabilized PKM2 and thereby regulated the proliferation and aerobic glycolysis in arsenite treated SV-HUC-1 cells. Taken together, these results provide new insights into mTORC1/HIF-1α and PKM2 networks as critical molecular targets that contribute to the arsenic-induced malignant progression of bladder epithelial cells.

Genomics analysis of three phosphorus-dissolving bacteria isolated from Torreya grandis soil

With the increasingly serious problem of phosphorus deficiency in the subtropical zone, chemical fertilizers are widely used. But it pollutes the environment. Phosphorus-solubilizing microorganisms (PSMs) are referred to as a new solution to this problem. We explored the phosphorus-dissolving characteristics of PSB strains isolated from the rhizosphere soil of Torreya grandis to provide a theoretical basis for selecting the strain for managing phosphorus deficiency in subtropical soils and also provides a more sufficient theoretical basis for the utilization of PSMs. From 84 strains, three strains exhibiting high phosphorus solubility and strong IAA producing capacity were selected through a series of experiments. The phosphate-solubilizing capacity of the three selected strains W1, W74, and W83 were 339.78 mg/L, 332.57 mg/L, and 358.61 mg/L, respectively. Furthermore, W1 showed the strongest IAA secreting capacity of 8.62 mg/L, followed by W74 (7.58 mg/L), and W83 (7.59 mg/L). Determination by metabolites, it was observed that these three strains dissolved phosphorus by secreting a large amount of lactic acid, aromatic acid, and succinic acid. The genome of these PSBs were sequenced and annotated in this study. Our results revealed that PSB primarily promotes their metabolic pathway, especially carbon metabolism, to secrete plenty organic acids for dissolving insoluble phosphorus.

One metal-ion-regulated AgTNPs etching sensor array for visual discrimination of multiple organic acids

The detection and discrimination of organic acids (OAs) is of great importance in the early diagnosis of specific diseases. In this study, we established an effective visual sensor array for the identification of OA. This is the first time, to our best knowledge, that metal ions were used to regulate the etching of silver triangular nanoprisms (AgTNPs) in an OA discrimination sensor array. The sensor array was based on the oxidation etching of AgTNPs by three metal ions (Mn²⁺, Pb²⁺, and Cr³⁺) and accelerated etching of AgTNPs by OA. The introduction of metal ions alone led to a slight wavelength shift of the AgTNPs colloid solution, signifying the incomplete etching of the AgTNPs. Nevertheless, when metal ions and OA were introduced simultaneously to the solution, a significant blueshift of the localized surface plasmon resonance peak was detected, and a color change of the AgTNPs was observed, which were the consequences of morphological transitions of the AgTNPs. The addition of different OA accelerated AgTNPs etching in varying degrees, generating diverse colorimetric response patterns (i.e., RGB variations) as "fingerprints" associated with each specific organic acid. Pattern recognition algorithms and neural network simulation were employed to further data analysis, indicating the outstanding discrimination capability of the provided array for eight OA at the 33 µM level. Moreover, excellent results of selective experiments as well as real samples tests demonstrate that our proposed method possesses great potential for practical applications.

Molecular and Physiological Responses of Citrus sinensis Leaves to Long-Term Low pH Revealed by RNA-Seq Integrated with Targeted Metabolomics

Low pH-induced alterations in gene expression profiles and organic acids (OA) and free amino acid (FAA) abundances were investigated in sweet orange [Citrus sinensis (L.) Osbeck cv. Xuegan] leaves. We identified 503 downregulated and 349 upregulated genes in low pH-treated leaves. Further analysis indicated that low pH impaired light reaction and carbon fixation in photosynthetic organisms, thereby lowering photosynthesis in leaves. Low pH reduced carbon and carbohydrate metabolisms, OA biosynthesis and ATP production in leaves. Low pH downregulated the biosynthesis of nitrogen compounds, proteins, and FAAs in leaves, which might be conducive to maintaining energy homeostasis during ATP deprivation. Low pH-treated leaves displayed some adaptive responses to phosphate starvation, including phosphate recycling, lipid remodeling, and phosphate transport, thus enhancing leaf acid-tolerance. Low pH upregulated the expression of some reactive oxygen species (ROS) and aldehyde detoxifying enzyme (peroxidase and superoxidase) genes and the concentrations of some antioxidants (L-tryptophan, L-proline, nicotinic acid, pantothenic acid, and pyroglutamic acid), but it impaired the pentose phosphate pathway and V_E and secondary metabolite biosynthesis and downregulated the expression of some ROS and aldehyde detoxifying enzyme (ascorbate peroxidase, aldo-keto reductase, and 2-alkenal reductase) genes and the concentrations of some antioxidants (pyridoxine and γ-aminobutyric acid), thus disturbing the balance between production and detoxification of ROS and aldehydes and causing oxidative damage to leaves.

Aspirin activates resolution pathways to reprogram T cell and macrophage responses in colitis-associated colorectal cancer

Inflammation is linked with carcinogenesis in many types of cancer including colorectal cancer (CRC). Aspirin is recommended for the prevention of CRC, although the mechanism(s) mediating its immunomodulatory actions remain incompletely understood. Here, we demonstrate that aspirin increased concentrations of the immune-regulatory aspirin-triggered specialized proresolving mediators (AT-SPMs), including AT-lipoxin A4 and AT-resolvin D1, in colonic tissues during inflammation-associated CRC (I-CRC). Aspirin also down-regulated the expression of the checkpoint protein programmed cell death protein-1 in macrophages and CD8+ T cells from the colonic mucosa. Inhibition of AT-SPM biosynthesis or knockout of the AT-SPM receptor Alx/Fpr2 reversed the immunomodulatory actions of aspirin on macrophages and CD8+ T cells and abrogated its protective effects during I-CRC. Furthermore, treatment of mice with AT-SPM recapitulated the immune-directed actions of aspirin during I-CRC. Together, these findings elucidate a central role for AT-SPM in mediating the immune-directed actions of aspirin in regulating I-CRC progression.

Analysis of urinary organic acids by gas chromatography tandem mass spectrometry method for metabolic profiling applications

A sensitive, accurate and precise method was developed for the quantification of a large number of organic acids in human urine by GC-MS/MS. The analytes were selected based on their role as key metabolic intermediates; intermediates of Krebs cycle, fatty acid oxidation, glycolysis, down-stream metabolites of neurotransmitter synthesis and degradation, metabolites indicative of nutritional deficiencies, byproducts of microbial activity in the gastrointestinal tract (GI) etc. The most efficient sample preparation protocol was selected based on tests for extraction with different solvents such as MTBE and ethyl acetate under acidic conditions, whereas finally a more general protocol was applied with methanol. Regarding derivatization, methoxyamine with MSTFA, 1% TMCS was applied. The method was extensively validated, including stability study, ensuring accurate determination of the studied organic acids in human urine. Proof of its utility was exhibited in a set of samples from human volunteers. The method can find wide applicability in the context of metabolomics for clinical or nutritional studies.

Loss of 15-lipoxygenase disrupts Treg differentiation altering their pro-resolving functions

Regulatory T-cells (Tregs) are central in the maintenance of homeostasis and resolution of inflammation. However, the mechanisms that govern their differentiation and function are not completely understood. Herein, we demonstrate a central role for the lipid mediator biosynthetic enzyme 15-lipoxygenase (ALOX15) in regulating key aspects of Treg biology. Pharmacological inhibition or genetic deletion of ALOX15 in Tregs decreased FOXP3 expression, altered Treg transcriptional profile and shifted their metabolism. This was linked with an impaired ability of Alox15-deficient cells to exert their pro-resolving actions, including a decrease in their ability to upregulate macrophage efferocytosis and a downregulation of interferon gamma expression in Th1 cells. Incubation of Tregs with the ALOX15-derived specilized pro-resolving mediators (SPM)s Resolvin (Rv)D3 and RvD5n-3 DPA rescued FOXP3 expression in cells where ALOX15 activity was inhibited. In vivo, deletion of Alox15 led to increased vascular lipid load and expansion of Th1 cells in mice fed western diet, a phenomenon that was reversed when Alox15-deficient mice were reconstituted with wild type Tregs. Taken together these findings demonstrate a central role of pro-resolving lipid mediators in governing the differentiation of naive T-cells to Tregs.

Elevated levels of urine isocitrate, hydroxymethylglutarate, and formiminoglutamate are associated with arterial stiffness in Korean adults

Recent evidence suggests that cellular perturbations play an important role in the pathogenesis of cardiovascular diseases. Therefore, we analyzed the association between the levels of urinary metabolites and arterial stiffness. Our cross-sectional study included 330 Korean men and women. The brachial-ankle pulse wave velocity was measured as a marker of arterial stiffness. Urinary metabolites were evaluated using a high-performance liquid chromatograph-mass spectrometer. The brachial-ankle pulse wave velocity was found to be positively correlated with l-lactate, citrate, isocitrate, succinate, malate, hydroxymethylglutarate, α-ketoisovalerate, α-keto-β-methylvalerate, methylmalonate, and formiminoglutamate among men. Whereas, among women, the brachial-ankle pulse wave velocity was positively correlated with cis-aconitate, isocitrate, hydroxymethylglutarate, and formiminoglutamate. In the multivariable regression models adjusted for conventional cardiovascular risk factors, three metabolite concentrations (urine isocitrate, hydroxymethylglutarate, and formiminoglutamate) were independently and positively associated with brachial-ankle pulse wave velocity. Increased urine isocitrate, hydroxymethylglutarate, and formiminoglutamate concentrations were associated with brachial-ankle pulse wave velocity and independent of conventional cardiovascular risk factors. Our findings suggest that metabolic disturbances in cells may be related to arterial stiffness.

GC-MS-based metabolomics reveals new biomarkers to assist the differentiation of prostate cancer and benign prostatic hyperplasia

Lack of efficient noninvasive biomarkers for differentiating prostate cancer (PCa) and benign prostate hyperplasia (BPH) is a serious concern for men's health worldwide. In this study, we aimed to improve the diagnostic capability of the existing noninvasive biomarkers for PCa. GC-MS-based untargeted metabolomics was employed to analyze plasma samples for 41 PCa patients and 38 BPH controls. Both univariate and multivariate statistical analyses were performed to screen for differential metabolites between PCa and BPH, followed by the selection of potential biomarkers through machine learning. The chosen candidate biomarkers were then verified by targeted analysis and transcriptome data. The results showed that twelve metabolites were significantly dysregulated between PCa and BPH, three metabolites including L-serine, myo-inositol, and decanoic acid could be potential biomarkers for discriminating PCa from BPH. Most importantly, ROC curve analysis demonstrated that the involvement of the three potential biomarkers has increased the area under the curve (AUC) value of cPSA and tPSA from 0.542 and 0.592 to 0.781, respectively. Therefore, it was concluded that the involvement of L-serine, myo-inositol, and decanoic acid can largely improve the diagnostic capability of the commonly used noninvasive biomarkers in the clinic for differentiating PCa from BPH.

Deep Ocean Water Concentrate Changes Physicochemical Characteristics, the Profile of Volatile Components and Consumer Acceptance for Taiwanese Rice Shochu

To study the effects of deep-ocean water concentrate (DOWC) on sake quality, Taichung No. 10 indica rice (Oryza sativa subsp. indica) and Tainan No. 11 japonica rice (O. sativa subsp. japonica) were used as raw materials, and basic physicochemical property parameters in shochu were analyzed differentially. Sake fermentation mash analysis results revealed that DOWC addition did not significantly affect the basic physicochemical properties during sake brewing, but it significantly reduced citric acid and malic acid contents in Taichung No. 10 indica rice sake sample by 52–66% and 73–93%, respectively. DOWC addition significantly increased citric acid content in Tainan No. 11 japonica rice sake sample by 32–202%. Rice shochu analysis results revealed that DOWC addition significantly increased isoamyl acetate, ethyl hexanoate, and ethyl octanoate contents in shochu made from japonica rice and indica rice, respectively. The results indicate that rice variety directly affects the types of volatile compounds in rice shochu. Principal component analysis and sensory evaluation results revealed that DOWC addition affected the composition of volatile compounds in the two types of rice shochu and resulted in differences in flavor evaluation. DOWC addition affects yeast metabolites and directly changes the volatile compound composition and flavor of rice shochu.

Rapid Quantification of Urinary Organic Acids by HPLC Mass Spectrometry to Assess Nutritional Individuality in Chinese Children

A urinary organic acids profile can be utilized as an effective screening tool for analyzing abnormality of nutrient metabolism. By using these metabolic markers in conjunction with one another, it helps in understanding how individual nutrient metabolism is executed and to determine where there may be imbalances in the metabolic cycle. In this study, we developed a rapid quantification method of 20 urinary organic acids by HPLC-mass spectrometry. A pre-analytical process of organic acid extraction from a urine sample is crucial in this methodology. The process was accomplished by liquid-liquid extraction followed by strong anion exchange. Compared with previous methods, this method greatly reduces the analysis time and allows for the simultaneous quantification of 20 organic acids within 10 min for the first time. This methodology enabled us to analyze urine samples collected from 34 Chinese children. The abnormalities of some urinary organic acids were found in this group, which revealed evidence of functional inadequacy of specific nutrients. The preliminary data in this study confirmed the suitability of the method for rapid and accurate quantification of the target organic acids in urine samples.

Prostate cancer screening using chemometric processing of GC-MS profiles obtained in the headspace above urine samples

The development of screening methods for various types of cancer is of utmost importance as the early diagnostics of these diseases significantly increases the chances for patient's successful medical treatment and recovery. In this study we have developed the procedure for chromatographic profiling of urine samples based on solid-phase microextraction and GC-MS. 50 urine samples (20 from the patients with biopsy conformed prostate cancer and 30 from control group) were studied in the optimized experimental conditions. Application of chemometric classification algorithms such as k-nearest neighbors and partial least squares-discriminant analysis allowed construction of predictive models yielding very high sensitivity, specificity and accuracy values all close to 100%. This gives a good promise for further validation of this approach with a broader sample sets.

Identification of short-chain poly-3-hydroxybutyrates in Saiga horn extracts using LC-MS/MS

Saiga horn extracts were analyzed with the goal of obtaining new information about compounds present in it. The purpose of this study is to find synthetic alternatives to Saiga horn extract, which is used in traditional Chinese medicine, by identifying potentially biologically active compounds in the extracts. Using high-performance liquid chromatography coupled with high-resolution mass spectrometry, we have been able to identify a series of short-chain polyhydroxybutyrates in alcoholic extracts of Saiga horn. Optimized high-performance liquid chromatography coupled with tandem mass spectrometry methods for analysis of short-chain poly-3-hydroxybutyrates were developed and subsequently applied to investigate Saiga horn extract for the presence of these compounds, which might explain its biological actions, particularly for its antipyretic and procoagulant properties.