Global metabolomics revealed deviations from the metabolic aging clock in colorectal cancer patients

Background: Markers of aging hold promise in the context of colorectal cancer (CRC) care. Utilizing high-resolution metabolomic profiling, we can unveil distinctive age-related patterns that have the potential to predict early CRC development. Our study aims to unearth a panel of aging markers and delve into the metabolomic alterations associated with aging and CRC. Methods: We assembled a serum cohort comprising 5,649 individuals, consisting of 3,002 healthy volunteers, 715 patients diagnosed with colorectal advanced precancerous lesions (APL), and 1,932 CRC patients, to perform a comprehensive metabolomic analysis. Results: We successfully identified unique age-associated patterns across 42 metabolic pathways. Moreover, we established a metabolic aging clock, comprising 9 key metabolites, using an elastic net regularized regression model that accurately estimates chronological age. Notably, we observed significant chronological disparities among the healthy population, APL patients, and CRC patients. By combining the analysis of circulative carcinoembryonic antigen levels with the categorization of individuals into the "hypo" metabolic aging subgroup, our blood test demonstrates the ability to detect APL and CRC with positive predictive values of 68.4% (64.3%, 72.2%) and 21.4% (17.8%, 25.9%), respectively. Conclusions: This innovative approach utilizing our metabolic aging clock holds significant promise for accurately assessing biological age and enhancing our capacity to detect APL and CRC.

Perfluorooctanesulfonic Acid and Perfluorooctanoic Acid Promote Migration of Three-Dimensional Colorectal Cancer Spheroids

Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are persistent environmental contaminants that are of increasing public concern worldwide. However, their relationship with colorectal cancer (CRC) is poorly understood. This study aims to comprehensively investigate the effect of PFOS and PFOA on the development and progression of CRC in vitro using a series of biological techniques and metabolic profiling. Herein, the migration of three-dimensional (3D) spheroids of two CRC cell lines, SW48 KRAS wide-type (WT) and SW48 KRAS G12A, were observed after exposure to PFOS and PFOA at 2 μM and 10 μM for 7 days. The time and dose-dependent migration phenotype induced by 10 μM PFOS and PFOA was further confirmed by wound healing and trans-well migration assays. To investigate the mechanism of action, derivatization-mass spectrometry-based metabolic profiles were examined from 3D spheroids of SW48 cell lines exposed to PFOS and PFOA (2 μM and 10 μM). Our findings revealed this exposure altered epithelial-mesenchymal transition related metabolic pathways, including fatty acid β-oxidation and synthesis of proteins, nucleotides, and lipids. Furthermore, this phenotype was confirmed by the downregulation of E-cadherin and upregulation of N-cadherin and vimentin. These findings show novel insight into the relationship between PFOS, PFOA, and CRC.

Analogy or fallacy, unsafe chemical alternatives: Mechanistic insights into energy metabolism dysfunction induced by Bisphenol analogs in HepG2 cells

Bisphenol analogs (BPs) are widely used as industrial alternatives for Bisphenol A (BPA). Their toxicity assessment in humans has mainly focused on estrogenic activity, while other toxicity effects and mechanisms resulting from BPs exposure remain unclear. In this study, we investigated the effects of three BPs (Bisphenol AF (BPAF), Bisphenol G (BPG) and Bisphenol PH (BPPH)) on metabolic pathways of HepG2 cells. Results from comprehensive cellular bioenergetics analysis and nontarget metabolomics indicated that the most important process affected by BPs exposure was energy metabolism, as evidenced by reduced mitochondrial function and enhanced glycolysis. Compared to the control group, BPG and BPPH exhibited a consistent pattern of metabolic dysregulation, while BPAF differed from both, such as an increased ATP: ADP ratio (1.29-fold, p < 0.05) observed in BPAF and significantly decreased ATP: ADP ratio for BPG (0.28-fold, p < 0.001) and BPPH (0.45-fold, p < 0.001). Bioassay endpoint analysis revealed BPG/BPPH induced alterations in mitochondrial membrane potential and overproductions of reactive oxygen species. Taken together these data suggested that BPG/BPPH induced oxidative stress and mitochondrial damage in cells results in energy metabolism dysregulation. By contrast, BPAF had no effect on mitochondrial health, but induced a proliferation promoting effect on cells, which might contribute to the energy metabolism dysfunction. Interestingly, BPPH induced the greatest mitochondrial damage among the three BPs but did not exhibit Estrogen receptor alpha (ERα) activating effects. This study characterized the distinct metabolic mechanisms underlying energy metabolism dysregulation induced by different BPs in target human cells, providing new insight into the evaluation of the emerging BPA substitutes.

Modulations in human neutrophil metabolome and S-glutathionylation of glycolytic pathway enzymes during the course of extracellular trap formation

Neutrophil extracellular trap formation (NETosis) has been irrefutably referred to as a distinct and unique form of active cell death with the purpose to counteract invading pathogens or augmenting the inflammatory cascade. Since the discovery, consistent efforts have been made to understand the various aspects of the initiation and sustenance of NETosis. In this study, using a global metabolomics approach during the phorbol 12-myristate 13-acetate (PMA) induced NETosis in human neutrophils, various metabolic pathways were found to be altered which includes intermediates related to, carbohydrate metabolism, and redox related metabolites, nucleic acid metabolism, and amino acids metabolism. Enrichment analysis of the metabolite sets highlighted the importance of the pentose phosphate pathway (PPP) and glutathione metabolism PMA-induced NETotic neutrophils. Further, analysis of the glutathyniolation status of neutrophil proteins by Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) indicated six different glutathionylated proteins: among them, two metabolically important proteins were α-enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) with MALDI score 166 and 70 respectively. Other proteins were lactoferrin, β-actin, c-myc promoter-binding protein, and uracil DNA glycosylase with MALDI scores of 96, 167, 104, and 68 respectively. Besides, activation of signalling proteins involved in metabolic regulation is also correlated with NETosis. Altogether, a balance between reactive oxygen species-glutathione metabolism seems to regulate the activity of glycolytic enzymes such as GAPDH and α-enolase during PMA-induced NETosis in a time-dependent manner.

Feeding state greatly modulates the effect of xenobiotics on gut microbiome metabolism: A case study of tetracycline

The human gut microbiome is crucial in modulating host health mostly through bacterial metabolites. Chemical exposure is typical external stress which alters its composition and functionality. To date, very few studies have investigated the effect of feeding state on chemical-induced gut microbial metabolic dysregulations. Here, we set up an in vitro human gut microbiome and incorporated a metabolomics approach to investigate the effect of tetracycline (TET) at multiple doses (i.e., 10, 1, and 0.01 mg/L) on gut microbiome under the fed and fasted states. Overall, the metabolome was highly responsive at the fed state with 62 metabolites dysregulated while only 14 were altered at the fasted state under 10 mg/L (clinical TET dose). As expected, nutrient consumption was significantly inhibited under clinical TET dose at the fed state accumulating nutrients such as glutamate and leucine. Interestingly, at the fed state, TET could increase the synthesis of indole and phenyl derivatives including indole-3-aldehyde and hydrocinnamate, while inhibiting indoxyl, tryptamine, and vitamin B production, all of which have host health implications. Furthermore, metabolites like indoxyl and xanthurenic acid were still responsive at 0.01 mg/L (dietary TET dose). Collectively, results demonstrated that the feeding state greatly modulates the chemical-induced gut microbial metabolic alterations.

Chemical Isotope Labeling LC-MS for Metabolomics

Due to the great diversity of chemical and physical properties of metabolites as well as a wide range of concentrations of metabolites present in metabolomic samples, performing comprehensive and quantitative metabolome analysis is a major analytical challenge. Conventional approach of combining various techniques and methods with each detecting a fraction of the metabolome can lead to the increase in overall metabolomic coverage. However, this approach requires extensive investment in equipment and analytical expertise with still relatively low coverage and low sample throughput. Chemical isotope labeling (CIL) liquid chromatography mass spectrometry (LC-MS) offers an alternative means of increasing metabolomic coverage while maintaining high quantification precision and accuracy. This chapter describes the CIL LC-MS method and its key features for metabolomic analysis.

Rate normalization for sweat metabolomics biomarker discovery

As the demand for real-time exercise performance feedback increases, excreted sweat has become a biosource of interest for continuous human performance assessment. For sweat to truly fulfill this requirement, analyte concentrations must be normalized to adequately assess day-to-day differences within and among individuals. In this manuscript, data are presented highlighting the use of accurate localized sweat rate as a means for ion and global metabolomic data normalization. The results illustrate large sweat rate variability among individuals over the course of two distinct exercises protocols. Furthermore, the data show sweat rate is not symmetrical at similar locations among right and left forearms of individuals (p = 0.0007). Sweat ion conductivity analysis suggest overall sweat rate normalization reduces variability collectively among ion values and participants with principal component analysis showing 77.8% of variation in the data set attributable to sweat rate normalization. Global metabolomic analysis of sweat illustrated overall rate normalization increases the variability among test subjects with 72.7% of the variation explained by sweat rate normalization. Finally, overall rate normalized metabolomic features of sweat significantly correlated (ρ ≥ 0.7, ρ ≤ -0.7) with measured performance metrics of the individual, establishing the potential for sweat to be used as a biosource for performance monitoring. Collectively, these data illustrate the importance of accurate localized sweat rate determination, for analyte data normalization, in support for the use of sweat in biomarker discovery efforts to predict human performance.

Ursodeoxycholic acid exerts hepatoprotective effects by regulating amino acid, flavonoid, and fatty acid metabolic pathways

INTRODUCTION

Ursodeoxycholic acid (UDCA) is an intestinal bacterial metabolite with hepatoprotective effects. However, molecular mechanisms underlying its effects remain unclear.

OBJECTIVES

The aim of this study was to investigate the mechanisms underlying the therapeutic effects of UDCA by using global metabolomics analyses in healthy subjects.

METHODS

Healthy Korean men were administered UDCA at dosage of 400, 800, or 1200 mg daily for 2 weeks. Serum samples were collected and used for liver function tests and to determine miR-122 expression levels. Urinary and plasma global metabolomics analyses were conducted using a liquid chromatography system coupled with quadrupole-time-of-flight mass spectrometry (LC/QTOFMS) and gas chromatography-TOFMS (GC/TOFMS). Unsupervised multivariate analysis (principal component analysis) was performed to identify discriminative markers before and after treatment.

RESULTS

Alanine transaminase score and serum miR-122 levels decreased significantly after 2 weeks of treatment. Through LC- and GC-based metabolomic profiling, we identified 40 differential metabolites in plasma and urine samples.

CONCLUSIONS

Regulation of liver function scores and metabolic alternations highlight the potential hepatoprotective action of UDCA, which were primarily associated with amino acid, flavonoid, and fatty acid metabolism in healthy men.

LC-Mass Spectrometry for Metabolomics

The field of metabolomics is greatly being refined by the addition of new technologies. LC-MS has allowed researchers to explore additional metabolites which were not originally captured through GC-MS. Through the customizability of the LC columns and mass spectrometer, it is now easier to tailor the instrument to your research needs. Herein, we describe a protocol for sample preparation and data acquisition for a global metabolomic analysis of tissues or feces.

Study of early stage non-small-cell lung cancer using Orbitrap-based global serum metabolomics

Purpose

The aim of the project was to apply ultra-high-performance liquid chromatography–quadrupole-Orbitrap-high-resolution mass spectrometry for serum metabolite profiling of non-small-cell lung cancer (NSCLC). This Orbitrap-based methodology has been applied for a study of NSCLC potential markers for the first time.

Methods

After extraction using protein precipitation, sera were separated on the ACE Excel 2 C18-PFP (100 × 2.1 mm, 2.0 µm) column using gradient elution and analyzed within the range of 70–1000 m/z. Only patients with early stage disease (stages IA–IIB) were included in the study, providing opportunity to find biomarkers for early lung cancer detection. The resulting metabolite profiles were subjected to univariate and multivariate statistical tests.

Results

36 features were found significantly changed between NSCLC group and controls after FDR adjustment and 19 were identified using various metabolite databases (in-house library, HMDB, mzCloud). The study revealed a number of NSCLC biomarker candidates which belong to such compound classes as acylcarnitines, organic acids, and amino acids. Multivariate ROC curve built using 12 identified metabolites was characterized by AUC = 0.836 (0.722–0.946). There were no significant differences in the serum metabolite profiles between two most common histological types of lung cancer—adenocarcinoma and squamous cell carcinoma.

Conclusions

Through identification of novel potential tumor markers, Orbitrap-based global metabolic profiling is a useful strategy in cancer research. Our study can accelerate development of new diagnostic and therapeutic strategies in NSCLC. The metabolites involved in discrimination between NSCLC patients and the control subjects should be further explored using a targeted approach.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-017-2347-0) contains supplementary material, which is available to authorized users.

Longitudinal Metabolite Profiling of Cerebrospinal Fluid in Normal Pressure Hydrocephalus Links Brain Metabolism with Exercise-Induced VEGF Production and Clinical Outcome

Idiopathic normal pressure hydrocephalus is a neurological disease caused by abnormal cerebrospinal fluid flow and presents with symptoms such as dementia. Current therapy involves the removal of excess cerebrospinal fluid by shunting. Not all patients respond to this therapy and biomarkers are needed that could facilitate the characterization of patients likely to benefit from this treatment. Here, we measure brain metabolism in normal pressure hydrocephalus patients by performing a novel longitudinal metabolomic profiling study of cerebrospinal fluid. We find that the levels of brain metabolites correlate with clinical parameters, the amount of vascular endothelial growth factor in the cerebrospinal fluid, and environmental stimuli such as exercise. Metabolomic analysis of normal pressure hydrocephalus patients provides insight into changes in brain metabolism that accompany cerebrospinal fluid disorders and may facilitate the development of new biomarkers for this condition.