Advances in purine and pyrimidine metabolism in health and diseases

Identification of potential biomarkers for diabetic cardiomyopathy using LC-MS-based metabolomics

Diabetic cardiomyopathy (DCM) is a serious complication of type 2 diabetes mellitus (T2DM) that contributes to cardiovascular morbidity and mortality. However, the metabolic alterations and specific biomarkers associated with DCM in T2DM remain unclear. In this study, we conducted a comprehensive metabolomic analysis using liquid chromatography-mass spectrometry (LC-MS) to investigate the plasma metabolite profiles of T2DM patients with and without DCM. We identified significant differences in metabolite levels between the groups, highlighting the dysregulation of various metabolic pathways, including starch and sucrose metabolism, steroid hormone biosynthesis, tryptophan metabolism, purine metabolism, and pyrimidine metabolism. Although several metabolites showed altered abundance in DCM, they also shared characteristics of DCM and T2DM rather than specific to DCM. Additionally, through biomarker analyses, we identified potential biomarkers for DCM, such as cytidine triphosphate, 11-ketoetiocholanolone, saccharopine, nervonic acid, and erucic acid. These biomarkers demonstrated distinct patterns and associations with metabolic pathways related to DCM. Our findings provide insights into the metabolic changes associated with DCM in T2DM patients and highlight potential biomarkers for further validation and clinical application. Further research is needed to elucidate the underlying mechanisms and validate the diagnostic and prognostic value of these biomarkers in larger cohorts.

Looking for the unexpected in purine and pyrimidine metabolism

In June 2023, the Purine and Pyrimidine Society (PPS) organized the 20th biennial symposium on Purine and Pyrimidine metabolism (PP23). The symposium was organized in Los Angeles, California, USA, by Pr Caius Radu affiliated to UCLA. The scientific program covered various topics such as inborn errors, cancer, immunity, enzymatic reactions, drug development etc and was presented at 9 sessions over three days. The current issue of Nucleosides, Nucleotides & Nucleic Acids is a special issue covering proceedings from PP23-presentations and other PPS-related manuscripts, and in this editorial, we will give an overview of the scientific program of the meeting.

New insights in research on purine and pyrimidine metabolism

In June 2021, the Purine and Pyrimidine Society (PPS) organized the 19th biennial symposium on Purine and Pyrimidine metabolism (PP21). Due to the ongoing pandemic, the conference was organized as a webinar over 3 days with sessions dealing with enzymes, cancer, inborn errors, gout among others. The current issue of Nucleosides, Nucleotides & Nucleic Acids is a special issue covering proceedings from PP21-presentations and other PPS-related manuscripts, and in this editorial, we will give an overview of the scientific program of the meeting.

Synthesis, characterization and molecular docking studies of new indol(1H-3-yl)pyrimidine derivatives: Insights into their role in DNA interaction

This study reports the synthesis of new indol(1H-3-yl) pyrimidine derivatives 4(a-e) using various substituted indole-3-carbaldehydes, urea and malononitrile in the presence of ammonium chloride. The resulting compounds were characterized using analytical and spectroscopic methods. The molecular docking study exhibits that among the synthesized compounds, 4(c-e) have great binding ability toward B-DNA. The binding efficiencies of compounds 4(c-e) with CT-DNA were evaluated via UV-visible absorption spectral and viscosity studies. The findings establish that the compounds firmly bind through an intercalative mode to CT-DNA and provide a unique pattern of DNA binding. The photo-induced cleavage indicates that the compounds have UV-visible photo nuclease properties toward plasmid DNA as revealed by agarose gel electrophoresis approach.

Uric Acid Elevation by Favipiravir, an Antiviral Drug

In light of the recent pandemic, favipiravir (Avigan^®), a purine nucleic acid analog and antiviral agent approved for use in influenza in Japan, is being studied for the treatment of coronavirus disease 2019 (COVID-19). Increase in blood uric acid level is a frequent side effect of favipiravir. Here, we discussed the mechanism of blood uric acid elevation during favipiravir treatment. Favipiravir is metabolized to an inactive metabolite M1 by aldehyde oxidase and xanthine oxidase, and excreted into urine. In the kidney, uric acid handling is regulated by the balance of reabsorption and tubular secretion in the proximal tubules. Favipiravir and M1 act as moderate inhibitors of organic anion transporter 1 and 3 (OAT1 and OAT3), which are involved in uric acid excretion in the kidney. In addition, M1 enhances uric acid reuptake via urate transporter 1 (URAT1) in the renal proximal tubules. Thus, favipiravir is thought to decrease uric acid excretion into urine, resulting in elevation of uric acid levels in blood. Elevated uric acid levels were returned to normal after discontinuation of favipiravir, and favipiravir is not used for long periods of time for the treatment of viral infection. Thus, the effect on blood uric acid levels was subclinical in most studies. Nevertheless, the adverse effect of favipiravir might be clinically important in patients with a history of gout, hyperuricemia, kidney function impairment (in which blood concentration of M1 increases), and where there is concomitant use of other drugs affecting blood uric acid elevation.

Recent updates on purine and pyrimidine metabolism in physiological and pathological settings

SUMMARYIn June 2019, the Purine and Pyrimidine Society (PPS) organized the 18th biennial symposium on Purine and Pyrimidine Metabolism at the International Agency for Research on Cancer in Lyon, France. This meeting went over 3 days and gathered students and researchers working in various specialties such as inborn errors, hyper- and hypouricemia and gout, cancer, enzymology, and cardiovascular diseases to exchange and discuss recent advances in the field of purine and pyrimidine metabolism. Here, we give an overview of oral presentations given during the symposium.

Analysis of Metabolite Profiling in Human Endothelial Cells after Plasma Jet Treatment

Cold atmospheric plasma (CAP) is a novel technology, which has been widely applied in biomedicine, especially in wound healing, dermatological treatment, hemostasis, and cancer treatment. In most cases, CAP treatment will interact with innumerable blood capillaries. Therefore, it is important and necessary to understand the effects of CAP treatment on endothelial cell metabolism. In this study, the metabolite profiling of plasma treatment on endothelial cells was measured by gas chromatography tandem time-of-flight mass spectrometry (GC-TOF-MS). We found that 695 signals (metabolites) were detected by GC-TOF-MS and then evaluated using orthogonal projections to latent structures discriminant analysis (OPLS-DA). All the differential metabolites were listed, and proline and xanthosine were the two of the most downregulated metabolites by plasma treatment. By comprehensive metabolic pathway analysis with the KEGG pathway, we showed that alanine, aspartate, glutamate, and purine metabolism pathways were the most significantly suppressed after gas plasma treatment in human endothelial cells. Our finding gives an overall picture of the metabolic pathways affected by plasma treatment in endothelial cells.

Computational analysis of receptor tyrosine kinase inhibitors and cancer metabolism: implications for treatment and discovery of potential therapeutic signatures

BACKGROUND

Receptor tyrosine kinase (RTK) inhibitors are frequently used to treat cancers and the results have been mixed, some of these small molecule drugs are highly successful while others show a more modest response. A high number of studies have been conducted to investigate the signaling mechanisms and corresponding therapeutic influence of RTK inhibitors in order to explore the therapeutic potential of RTK inhibitors. However, most of these studies neglected the potential metabolic impact of RTK inhibitors, which could be highly associated with drug efficacy and adverse effects during treatment.

METHODS

In order to fill these knowledge gaps and improve the therapeutic utilization of RTK inhibitors a large-scale computational simulation/analysis over multiple types of cancers with the treatment responses of RTK inhibitors was performed. The pharmacological data of all eight RTK inhibitor and gene expression profiles of 479 cell lines from The Cancer Cell Line Encyclopedia were used.

RESULTS

The potential metabolic impact of RTK inhibitors on different types of cancers were analyzed resulting in cancer-specific (breast, liver, pancreas, central nervous system) metabolic signatures. Many of these are in line with results from different independent studies, thereby providing indirect verification of the obtained results.

CONCLUSIONS

Our study demonstrates the potential of using a computational approach on signature-based-analysis over multiple cancer types. The results reveal the strength of multiple-cancer analysis over conventional signature-based analysis on a single cancer type.

Metabolic and Proteomic Responses to Long-Term Protein Restriction in a Pig Model

Protein restriction is associated with extended lifespan and reduced incidence and progression of multiple age-related diseases. The underlying mechanism of metabolic and proteomic responses to the long-term dietary protein restriction, however, has not been fully uncovered. The present study aimed to identify the metabolic and proteomic profiles in a low-protein diet-fed pig model. Intestinal and liver metabolomics showed that amino acid metabolism was highly associated with dietary protein restriction. Interestingly, blood was characterized by markedly higher abundances of Ser, Gly, Glu, Thr, Ala, Lys, and Met levels, and lower abundances of His, Val, and Ile levels regardless of the age of pigs from piglets to adult pigs. Amino acid transporters might contribute to the changed amino acid pools and serve as a feedback regulatory mechanism in response to protein restriction. iTRAQ-based quantitative proteomics approach identified more than 10 differently expressed proteins in protein restricted pigs and KEGG pathway analysis showed that significant enrichment of proteins involved in metabolic pathways, PI3K-Akt signaling pathway, lysosome, spliceosome, oxidative phosphorylation, phagosome, and DNA replication. Western blot analysis further confirmed that protein restriction markedly inactivated Akt and mTOR signals in pigs. This study indicates that dietary protein restriction leads to a shift in the host metabolism in a pig model, especially for amino acid metabolism. Along with proteomics, our findings unveil potential mechanisms for integrating how protein restriction modulates host metabolism.