ACOT1 deficiency attenuates high-fat diet-induced fat mass gain by increasing energy expenditure

Protective Effect of Modified Suanmei-Tang on Metabolic-Associated Fatty Liver Disease: An Integrated Strategy of Network Pharmacology, Metabolomics, and Transcriptomics

Background

Modified Suanmei-Tang (MST) comprises four plants common to both traditional Chinese medicine and culinary applications, and it can potentially alleviate metabolic-associated fatty liver disease (MAFLD) triggered by a high-fat diet (HFD).

Purpose

This research aims to investigate the impact and underlying mechanisms of MST in ameliorating MAFLD caused by an HFD.

Methods

UHPLC-Q-Orbitrap-MS/MS was used to determine the constituents of MST and to evaluate its effects on MAFLD mouse models. Transcriptomics, network pharmacology, and bioinformatics analysis (including Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis) were utilized to further clarify the mechanisms by which MST acts on MAFLD. The experimental methods included ELISA, real time quantitative PCR (RT-qPCR), Western blot, immunohistochemistry, molecular docking, and metabolomics. Transcriptomics was integrated with metabolomics to find correlations between differentially expressed genes and metabolites, and crucial genes were validated through RT-qPCR.

Results

A total of 23 components of MST were identified. The formulation was found to alleviate metabolic disorders, obesity, insulin resistance, inflammation, and oxidative stress in mice with MAFLD. The findings indicate that MST promoted autophagy by suppressing phosphorylation in the PI3K/AKT/mTOR pathway and enhancing lipid management in the livers of MAFLD mice.

Conclusion

MST could effectively improve lipid metabolism disorders and liver lipid deposition in MAFLD mice, and its mechanism might be related to regulating the PI3K/AKT/mTOR pathway to improve autophagy.

Futile cycles: Emerging utility from apparent futility

Futile cycles are biological phenomena where two opposing biochemical reactions run simultaneously, resulting in a net energy loss without appreciable productivity. Such a state was presumed to be a biological aberration and thus deemed an energy-wasting "futile" cycle. However, multiple pieces of evidence suggest that biological utilities emerge from futile cycles. A few established functions of futile cycles are to control metabolic sensitivity, modulate energy homeostasis, and drive adaptive thermogenesis. Yet, the physiological regulation, implication, and pathological relevance of most futile cycles remain poorly studied. In this review, we highlight the abundance and versatility of futile cycles and propose a classification scheme. We further discuss the energetic implications of various futile cycles and their impact on basal metabolic rate, their bona fide and tentative pathophysiological implications, and putative drug interactions.

SWATH-MS reveals that bisphenol A and its analogs regulate pathways leading to disruption in insulin signaling and fatty acid metabolism

Bisphenol A (BPA) is an endocrine-disrupting chemical (EDC), associated with obesity and insulin resistance. The FDA prohibited the use of BPA-based polycarbonate resins in infant formula packaging; thus, its analogs, viz. Bisphenol S (BPS) and Bisphenol F (BPF) were considered alternatives in epoxy resins, plastics, and food cans. As these analogs might evoke a similar response, we investigated the role of Bisphenols (BPA, BPF, and BPS), on insulin signaling in CHO-HIRc-myc-GLUT4eGFP cells at environmentally relevant concentrations of 2 nM and 200 nM. Insulin signaling demonstrated that Bisphenols reduced phosphorylation of IR and AKT2, GLUT4 translocation, and glucose uptake. This was accompanied by increased oxidative stress. Furthermore, SWATH-MS-based proteomics of 3T3-L1 cells demonstrated that Bisphenol-treated cells regulate proteins in insulin resistance, adipogenesis, and fatty acid metabolism pathways differently. All three Bisphenols induced differentially expressed proteins enriched similar pathways, although their abundance differed for each Bisphenol. This might be due to their varying toxicity level, structural differences, and estrogen-mimetic activity. This study has important implications in addressing health concerns related to EDCs. Given that the analogs of BPA are considered alternatives to BPA, the findings of this study suggest they are equally potent in altering fatty acid metabolism and inducing insulin resistance.

Futile lipid cycling: from biochemistry to physiology

In the healthy state, the fat stored in our body isn't just inert. Rather, it is dynamically mobilized to maintain an adequate concentration of fatty acids (FAs) in our bloodstream. Our body tends to produce excess FAs to ensure that the FA availability is not limiting. The surplus FAs are actively re-esterified into glycerides, initiating a cycle of breakdown and resynthesis of glycerides. This cycle consumes energy without generating a new product and is commonly referred to as the 'futile lipid cycle' or the glyceride/FA cycle. Contrary to the notion that it's a wasteful process, it turns out this cycle is crucial for systemic metabolic homeostasis. It acts as a control point in intra-adipocyte and inter-organ cross-talk, a metabolic rheostat, an energy sensor and a lipid diversifying mechanism. In this Review, we discuss the metabolic regulation and physiological implications of the glyceride/FA cycle and its mechanistic underpinnings.