Introduction: Acute kidney injury (AKI) is linked to high rates of mortality and morbidity worldwide thereby posing a major public health problem. Evidences suggest that ferroptosis is the primary cause of AKI, while inhibition of monoamine oxidase A(MAOA) and 5-hydroxytryptamine were recognized as the defender of ferroptosis. Curcumin (Cur) is a natural polyphenol and the main bioactive compound of Curcuma longa, which has been found nephroprotection in AKI. However, the potential mechanism of Cur in alleviating AKI ferroptosis remains unknown. Objective: This study aims to investigate the effects of Cur on AKI ferroptosis. Methods: Folic acid (FA)-induced AKI mouse model and erastin/(rsl-3)-induced HK-2 model were constructed to assess the renoprotection of Cur. The nuclear magnetic resonance (NMR)-based metabolomics coupled network pharmacology approach was used to explore the metabolic regulation and potential targets of Cur. Molecular docking and enzyme activity assay was carried out to evaluate the effects of Cur on MAOA. Results: Our results showed that in vivo Cur preserved renal functions in AKI mice by lowering levels of serum creatinine, blood urea nitrogen, while in vitro ameliorated the cell viability of HK-2 cells damaged by ferroptosis. Mechanistic studies indicated that Cur protected AKI against ferroptosis via inhibition of MAOA thereby regulating 5-hydroxy-L-tryptophan metabolism. Conclusion: Our study for the first time clarified that Cur might acts as a MAOA inhibitor and alleviates ferroptosis in AKI mice, laying a scientific foundation for new insights of clinical therapy on AKI.

The gut microbial metabolite trimethylamine N-oxide (TMAO) has received increased attention due to its close relationship with cardiovascular disease and type 2 diabetes. In previous studies, TMAO has shown both harmful and beneficial effects on various tissues, but the underlying molecular mechanisms remain to be clarified. Here, we explored the effects of TMAO treatment on H₂O₂-impaired C2C12 myoblasts, analyzed metabolic changes and identified significantly altered metabolic pathways through nuclear magnetic resonance-based (NMR-based) metabolomic profiling. The results exhibit that TMAO treatment partly alleviated the H₂O₂-induced oxidative stress damage of cells and protected C2C12 myoblasts by improving cell viability, increasing cellular total superoxide dismutase capacity, improving the protein expression of catalase, and reducing the level of malondialdehyde. We further showed that H₂O₂ treatment decreased levels of branched-chain amino acids (isoleucine, leucine and valine) and several amino acids including alanine, glycine, threonine, phenylalanine and histidine, and increased the level of phosphocholine related to cell membrane structure, while the TMAO treatment partially reversed the changing trends of these metabolite levels by improving the integrity of the cell membranes. This study indicates that the TMAO treatment may be a promising strategy to alleviate oxidative stress damage in skeletal muscle.

Trimethylamine N-oxide (TMAO) has attracted interest because of its association with cardiovascular disease and diabetes, and evidence for the beneficial effects of TMAO is accumulating. This study investigates the role of TMAO in improving exercise performance and elucidates the underlying molecular mechanisms. Using C2C12 cells, we established an oxidative stress model and administered TMAO treatment. Our results indicate that TMAO significantly protects myoblasts from oxidative stress-induced damage by increasing the expression of Nrf2, heme oxygenase-1 (HO-1), NAD(P)H dehydrogenase (NQO1), and catalase (CAT). In particular, suppression of Nrf2 resulted in a loss of the protective effects of TMAO and a significant decrease in the expression levels of Nrf2, HO-1, and NQO1. In addition, we evaluated the effects of TMAO in an exhaustive swimming test in mice. TMAO treatment significantly prolonged swimming endurance, increased glutathione and taurine levels, enhanced glutathione peroxidase activity, and increased the expression of Nrf2 and its downstream antioxidant genes, including HO-1, NQO1, and CAT, in skeletal muscle. These findings underscore the potential of TMAO to counteract exercise-induced oxidative stress. This research provides new insights into the ability of TMAO to alleviate exercise-induced oxidative stress via the Nrf2 signaling pathway, providing a valuable framework for the development of sports nutrition supplements aimed at mitigating oxidative stress.

To improve exercise performance, the supplement of nutrients has become a common practice before prolonged exercise. Trimethylamine N-oxide (TMAO) has been shown to ameliorate oxidative stress damage, which may be beneficial in improving exercise capacity. Here, we assessed the effects of TMAO on mice with exhaustive swimming, analyzed the metabolic changes, and identified significantly altered metabolic pathways of skeletal muscle using a nuclear magnetic resonance-based (NMR-based) metabolomics approach to uncover the effects of TMAO improving exercise performance of mice. We found that TMAO pre-administration markedly prolonged the exhaustive time in mice. Further investigation showed that TMAO pre-administration increased levels of 3-hydroxybutyrate, isocitrate, anserine, TMA, taurine, glycine, and glutathione and disturbed the three metabolic pathways related to oxidative stress and protein synthesis in skeletal muscle. Our results provide a metabolic mechanistic understanding of the effects of TMAO supplements on the exercise performance of skeletal muscle in mice. This work may be beneficial in exploring the potential of TMAO to be applied in nutritional supplementation to improve exercise performance. This work will lay a scientific foundation and be beneficial to exploring the potential of TMAO to apply in nutritional supplementation.

The purpose of this study was to explore the protective effect of 8 weeks of Moderate Intensity Continuous Training (MICT) on TMAO-induced myocardial injury in mice and its metabolic regulatory mechanism based on nuclear magnetic resonance (NMR) metabolomics methods. Male C57BL/6J mice were randomly allocated into the following groups: Control group (Con, n = 15), TMAO-induced myocardial injury group (TMAO, n = 15), and TMAO-induced with MICT intervention group (Exe, n = 15). TMAO and Exe groups underwent 8 weeks of high-dose TMAO gavage to establish a myocardial injury model, with the Exe group additionally receiving 8 weeks of MICT intervention (60 min/session, 5 sessions/week, 50% MRC). After the 8 weeks of interventions, the mouse heart function was tested using cardiac ultrasound equipment; myocardial histology was evaluated using HE staining; and myocardial tissue samples were collected for NMR metabolomics analysis. Compared with the Con group, the HR in the TMAO group was significantly increased, while EF and LVFS were significantly decreased. Compared with the TMAO group, the HR in the Exe group was significantly reduced, and EF and LVFS were significantly increased; NMR metabolomics analysis showed that, compared with the Con group, five metabolic pathways including phenylalanine metabolism, tyrosine metabolism, and TCA cycle were significantly altered in the TMAO group; compared with the TMAO group, ten metabolic pathways related to amino acid metabolism (such as alanine, glycine, etc.), energy metabolism (TCA cycle), and oxidative stress (purine metabolism) were significantly regulated in the Exe group. MICT could effectively alleviate TMAO-induced myocardial injury in mice by regulating multiple targets within the myocardial metabolic pathways. These findings provide a theoretical basis for the clinical application of exercise intervention in myocardial injury treatment.