MTA-TST Axis-Mediated Apoptosis Activation: A Multi-Omics Insight Into High-Protein Diet's Anti-Adiposity Effect

To explore the mechanism of a high-protein diet (named high protein and rich fat diet, HPRFD) with weight loss effect regulating visceral fat metabolism through endogenous metabolites. Non-targeted metabonomics compared the spectrum of different metabolites in different groups of experimental mice, and targeted metabonomics examined the target metabolite in visceral adipose tissue (VAT). VAT transcriptomics identified differentially expressed genes. Multi-mics joint analysis identified target metabolites, genes, and their relationships. Functional annotation revealed shared signaling pathways. 3T3-L1 adipocytes were treated with metabolites to observe changes in morphology, mitochondrial function, and expression of key genes in the signal pathway. The gene knockdown experiment evaluated the changes in key metabolites in the above functions of cells. Molecular docking predicted metabolite-protein binding sites. The results showed that 5'-deoxy-5'-(methylthio)adenosine (MTA) was significantly elevated in the HPRFD group (p < 0.05). Fecal MTA negatively correlated with TST gene of VAT expression (r = -0.90/-0.89). KEGG analysis showed co-enrichment in apoptosis pathways. HPRFD upregulated TST (1.31-fold), Bak (6.52-fold, p < 0.01), and Casp-3 (2.35-fold, p < 0.05) versus HFD. In vitro, 400 μmol/L MTA increased mitochondrial membrane potential (JC-1 ratio +0.13, p < 0.0001) and upregulated TST, Bak, and Casp-3. The effect of MTA in restoring mitochondrial membrane potential and promoting the expression of Bak and Casp-3 genes disappeared after TST knockdown. Molecular docking predicted strong MTA-TST binding (ΔG = -1.2 kcal/mol). HPRFD reduced VAT through MTA-TST-Bak/Casp-3 axis, suggesting that MTA has the potential to be developed as a functional substance for obesity prevention and control.