Mitochondrial 2,4-dienoyl-CoA reductase (Decr) deficiency and impairment of thermogenesis in mouse brown adipose tissue

Mouse models of NADK2 deficiency analyzed for metabolic and gene expression changes to elucidate pathophysiology

NADK2 encodes the mitochondrial form of nicotinamide adenine dinucleotide (NAD) kinase, which phosphorylates NAD. Rare recessive mutations in human NADK2 are associated with a syndromic neurological mitochondrial disease that includes metabolic changes, such as hyperlysinemia and 2,4 dienoyl CoA reductase (DECR) deficiency. However, the full pathophysiology resulting from NADK2 deficiency is not known. Here, we describe two chemically induced mouse mutations in Nadk2-S326L and S330P-which cause severe neuromuscular disease and shorten lifespan. The S330P allele was characterized in detail and shown to have marked denervation of neuromuscular junctions by 5 weeks of age and muscle atrophy by 11 weeks of age. Cerebellar Purkinje cells also showed progressive degeneration in this model. Transcriptome profiling on brain and muscle was performed at early and late disease stages. In addition, metabolomic profiling was performed on the brain, muscle, liver and spinal cord at the same ages and on plasma at 5 weeks. Combined transcriptomic and metabolomic analyses identified hyperlysinemia, DECR deficiency and generalized metabolic dysfunction in Nadk2 mutant mice, indicating relevance to the human disease. We compared findings from the Nadk model to equivalent RNA sequencing and metabolomic datasets from a mouse model of infantile neuroaxonal dystrophy, caused by recessive mutations in Pla2g6. This enabled us to identify disrupted biological processes that are common between these mouse models of neurological disease, as well as those processes that are gene-specific. These findings improve our understanding of the pathophysiology of neuromuscular diseases and describe mouse models that will be useful for future preclinical studies.

Integrative proteomics and metabolomics of Guizhou Miao Sour Soup affecting simple obese rats

Miao Sour Soup (MSS) is a fermented product from the Qiandongnan region of Guizhou Province, which enrich many beneficial ingredients and is widely consumed in the whole China. Fermented food is beneficial to physical health with the potential positive regulating affection on simple obesity. In this study, we analyzed the mechanism of action of MSS to prevent simple obesity induced by high-fat diet by proteomics and metabolomics. Quantitative proteomics with tandem mass tagging labeling and liquid chromatography-mass spectrometry was used to analyze the changes of liver proteins and metabolites after the MSS intervention. MSS intervention upregulated 33 proteins and 9 metabolites and downregulated 19 proteins and 10 metabolites. Bioinformatics analysis showed that MSS could prevent simple obesity by acting on the PPAR signaling pathway, retinol metabolism, fatty acid β-oxidation, fatty acid degradation, fatty acid biosynthesis, glycine, serine and threonine metabolism, pyruvate metabolism, citrate cycle (TCA cycle) and other signaling pathways. This study provides new insights into the use of MSS to prevent simple obesity caused by high-fat diets and the search for healthy eating patterns with MSS.

Integration of organ metabolomics and proteomics in exploring the blood enriching mechanism of Danggui Buxue Decoction in hemorrhagic anemia rats

ETHNOPHARMACOLOGICAL RELEVANCE

Danggui Buxue Decoction (DBD), as a classical Chinese medicine prescription, is composed of Danggui (DG) and Huangqi (HQ) at a ratio of 1:5, and it has been used clinically in treating anemia for hundreds of years.

AIM OF THE STUDY

The aim of this study was to explore the treatment mechanisms of DBD in anemia rats from the perspective of thymus and spleen.

MATERIALS AND METHODS

In this study, a successful hemorrhagic anemia model was established, and metabolomics (UPLC-QTOF-MS/MS) and proteomics (label-free approach) together with bioinformatics (Gene Ontology analysis and Reactome pathway enrichment), correlation analysis (pearson correlation matrix) and joint pathway analysis (MetaboAnalyst) were employed to discover the underlying mechanisms of DBD.

RESULTS

DBD had a significant blood enrichment effect on hemorrhagic anemia rats. Metabolomics and proteomics results showed that DBD regulated a total of 10 metabolites (lysophosphatidylcholines, etc.) and 41 proteins (myeloperoxidase, etc.) in thymus, and 9 metabolites (L-methionine, etc.) and 24 proteins (transferrin, etc.) in spleen. With GO analysis and Reactome pathway enrichment, DBD mainly improved anti-oxidative stress ability of thymocyte and accelerated oxidative phosphorylation to provide ATP for splenocyte. Phenotype key indexes were strongly and positively associated with most of the differential proteins and metabolites, especially nucleosides, amino acids, Fabp4, Decr1 and Ndufs3. 14 pathways in thymus and 9 pathways in spleen were obtained through joint pathway analysis, in addition, the most influential pathway in thymus was arachidonic acid metabolism, while in spleen was the biosynthesis of phenylalanine, tyrosine and tryptophan. Furthermore, DBD was validated to up-regulate Mpo, Hbb and Cp levels and down-regulate Ca²⁺ level in thymus, as well as up-regulate Fabp4, Ndufs3, Tf, Decr1 and ATP levels in spleen.

CONCLUSION

DBD might enhance thymus function mainly by reducing excessive lipid metabolism and intracellular Ca²⁺ level, and promote ATP production in spleen to provide energy.

Mass spectrometry-based determination of lipids and small molecules composing adipose tissue with a focus on brown adipose tissue

Adipose tissue has been the subject of research for a very long time. Many studies perform a comprehensive analysis of different types of adipose tissue with an emphasis on brown adipose tissue. Mass spectrometry-based approaches are particularly useful in the exploration not only of the metabolic composition of adipose tissue but also its function. In the presented review, a complex and critical overview of publications devoted to the analysis of adipose tissue by means of mass spectrometry was performed. Detailed investigation of analytical aspects related to either untargeted or targeted analysis of adipose tissue was performed, leading to the formation of a collection of hints at the available analytical methods. Moreover, a profound analysis of the metabolic composition of brown adipose tissue was performed. Brown adipose tissue metabolome was characterized on structural and functional levels, providing information about its exact metabolic composition but also connecting these molecules and placing them into biochemical pathways. All our work resulted in a very broad picture of the analysis of adipose tissue, starting from the analytical aspects and finishing on the current knowledge about its composition.

Human DECR1 is an androgen-repressed survival factor that regulates PUFA oxidation to protect prostate tumor cells from ferroptosis

Fatty acid β-oxidation (FAO) is the main bioenergetic pathway in human prostate cancer (PCa) and a promising novel therapeutic vulnerability. Here we demonstrate therapeutic efficacy of targeting FAO in clinical prostate tumors cultured ex vivo, and identify DECR1, encoding the rate-limiting enzyme for oxidation of polyunsaturated fatty acids (PUFAs), as robustly overexpressed in PCa tissues and associated with shorter relapse-free survival. DECR1 is a negatively-regulated androgen receptor (AR) target gene and, therefore, may promote PCa cell survival and resistance to AR targeting therapeutics. DECR1 knockdown selectively inhibited β-oxidation of PUFAs, inhibited proliferation and migration of PCa cells, including treatment resistant lines, and suppressed tumor cell proliferation and metastasis in mouse xenograft models. Mechanistically, targeting of DECR1 caused cellular accumulation of PUFAs, enhanced mitochondrial oxidative stress and lipid peroxidation, and induced ferroptosis. These findings implicate PUFA oxidation via DECR1 as an unexplored facet of FAO that promotes survival of PCa cells.

Regulation of thermogenic adipocytes during fasting and cold

Cold exposure activates brown and brown-like adipocytes that dissipate large amounts of glucose and fatty acids via uncoupling protein 1 (UCP1) to drive non-shivering thermogenesis (NST). Evidence for the existence of these thermogenic adipocytes in adult humans gave rise to a renaissance in research on brown adipose tissue, establishing it as linchpin of energy homeostasis and metabolic health. Besides low ambient temperature, shortage or excess of food affect thermoregulation. Upon high caloric meals thermogenic adipocytes burn excess calories and maintain energy balance. In contrast, in conditions of nutrient deprivation, counter-regulatory mechanisms prevent thermogenic adipocytes from "wasting" energy substrates that need to be conserved. In this review, we discuss cell-autonomous mechanisms, metabolites, and hormones that modify NST in response to nutrient fluctuations. In particular, we focus on how thermogenic adipocytes balance thermogenesis with systemic energy homeostasis during fasting periods.