ABSTRACT
Rosa davurica Pall. (RDP) fruits are popularly consumed as beverages and healthy food in China because of their various beneficial activities. In particular, flavonoids are one of the major active ingredients of RDP fruits with predominant pharmacological effects. However, the anti-obesity activities of flavonoids from RDP fruits and their regulation effect on the gut microbiota have not been determined. In the present study, the flavonoid-rich extracts (RDPF) were isolated from RDP fruits and their anti-obesity effects were investigated using a high-fat diet (HFD)-induced obese mouse model. The results showed that RDPF intervention significantly inhibited the body weight, liver weight, kidney weight and epididymal adipose tissue weight of HFD-fed mice without affecting the calorie intake. Plasma lipid levels were also significantly lowered by RDPF treatment. Histological examination showed that RDPF supplementation partially recovered HFD-induced hepatic steatosis in the liver. RDPF also prevented oxidative injury of the liver, as evidenced by the altered superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) levels. The expression levels of CCAAT/enhancer binding protein α (C/EBPα), sterol regulatory element binding protein-1C (SREBP-1C), fatty acid synthase (FAS), acyl-coenzyme A oxidase 1 (ACOX1), peroxisome proliferator-activated receptor (PPARα) and CAT mRNA in the livers of mice were also regulated by RDPF administration. 16S rRNA gene sequence data further indicated that RDPF addition increased the microbial diversity and reshaped the community composition. Intriguingly, RDPF intervention did not exhibit inhibitory tendency toward the ratio of Firmicutes to Bacteroidetes, but markedly decreased the relative abundance of Erysipelotrichaceae. This study provided novel insights into the application of RDPF in the food industry.
Subject(s)
Fatty Liver/drug therapy , Flavonoids/pharmacology , Gastrointestinal Microbiome/drug effects , Obesity/drug therapy , Rosa/chemistry , Adipose Tissue/metabolism , Animals , Anti-Obesity Agents/pharmacology , CCAAT-Enhancer-Binding Protein-alpha/metabolism , Diet, High-Fat/adverse effects , Fatty Liver/metabolism , Fruit/chemistry , Lipids/blood , Liver/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Obese , Obesity/metabolism , PPAR alpha/metabolism , RNA, Ribosomal, 16S/metabolism , Sterol Regulatory Element Binding Protein 1/metabolismABSTRACT
BACKGROUND: Excess lipid accumulation can accelerate the development of various metabolic diseases. Blossoms of Citrus aurantium L. var. amara Engl. (CAVA) have been reported to possess inhibitory capacities on lipid deposition. However, the constituents responsible for the observed bioactivity and the underlying mechanisms are still not clearly understood. PURPOSE: To screen constituents from blossoms of CAVA with inhibitory effects on lipid accumulation and to explore the action mechanism. METHODS: The chloroform (CHL) extracts are prepared from blossoms of CAVA by fractional extraction and are characterized using LC-MS assay. 3T3-L1 preadipocytes are induced with differentiation medium (DMI) and treated with CHL extracts. High fat diet (HFD)-induced obese mice are further established and administrated with CHL extracts for 12 weeks. Hematoxylin and eosin (HE) staining, Oil Red O staining, ELISA, RT-qPCR, western blot and 16S rRNA gene sequence methods are employed. RESULTS: 14 compounds are identified in CHL extracts and trigonelline hydrochloride, nobiletin and 7-demethylsuberosin are most abundant. CHL extracts treatment significantly inhibit differentiation of 3T3-L1 cells by regulating expression of preadipocyte factor-1 (Pref-1), fatty acid synthase (FAS) and CCAAT/enhancer binding protein α (C/EBPα). CHL extracts intervention also significantly attenuate features of obesity and improved plasma biochemical profiles in HFD-fed mice. HFD-triggered hepatic steatosis and epididymal adipose tissues (EATs) hypertrophy are also reversed by CHL extracts administration through enhancing antioxidant responses and modulating lipogenesis and energy expenditure-related genes and proteins. 16S rRNA gene sequence data further show that CHL extracts enhance the diversity of gut microbiota. CHL extracts at lower concentrations reduce the ratio of Firmicutes to Bacteroidetes and the abundance of Erysipelotrichaceae. CHL extracts at higher doses markedly increase the abundance of Lachnospiraceae. CONCLUSION: These findings suggest that CHL extracts probably suppress lipid accumulation through inhibiting differentiation of 3T3-L1 cells and attenuating metabolic syndromes in HFD-fed mice.
Subject(s)
Adipogenesis/drug effects , Citrus , Lipid Metabolism/drug effects , Plant Extracts , 3T3-L1 Cells , Animals , Chloroform , Citrus/chemistry , Diet, High-Fat , Gastrointestinal Microbiome , Mice , Mice, Inbred C57BL , Mice, Obese , Plant Extracts/pharmacology , RNA, Ribosomal, 16SABSTRACT
tRNA molecules are the adaptors in ribosome-based protein biosynthesis and are stabilized by Mg(2+). However, the detailed mechanism for the Mg(2+) mediated stability is not fully understood. To study the effects of Mg(2+) on conformational flexibility of Escherichia coli tRNA(Leu) (CAG) at millisecond timescale, we applied NMR spectroscopic approach to measure proton exchange rates of imino groups in the presence of different concentration of Mg(2+) and correlated them with the corresponding aminoacylation activity of tRNA(Leu). Here, we report the first part of the above mentioned study, the (1)H, (15)N chemical shift assignments of the imino groups in all base pairs of Escherichia coli tRNA(Leu) (CAG) based on 2D (1)H-(15)N TROSY, 2D NOESY and 3D NOESY-HMQC experiments. This work laid the foundation for the NMR study of tRNA(Leu) (BMRB deposits with accession number 17078).
Subject(s)
Base Pairing/genetics , Escherichia coli/genetics , Imines/chemistry , Nuclear Magnetic Resonance, Biomolecular , RNA, Transfer, Leu/genetics , Anticodon/genetics , Base Sequence , Hydrogen , Molecular Sequence Data , Nitrogen Isotopes , Nucleic Acid Conformation , RNA, Transfer, Leu/chemistryABSTRACT
The millisecond conformational flexibility is functionally important for nucleic acids and can be studied through probing the base pair open-close kinetics by proton exchange nuclear magnetic resonance (NMR) spectroscopy. Here, the traditional imino proton exchange NMR experiments were modified with transverse relaxation optimized spectroscopy and were applied to accurately measure imino proton exchange rates of all base pairs in Escherichia coli tRNA(Leu) (CAG), and their dependence on magnesium ion concentration. Finally, we correlated millisecond conformational flexibility with aminoacylation of tRNA(Leu) and proposed that the flexibility of the acceptor stem and the core region might contribute to aminoacylation of tRNA(Leu).
Subject(s)
Base Pairing , Magnetic Resonance Spectroscopy/methods , Protons , RNA, Transfer/chemistry , Aminoacylation , Base Sequence , Escherichia coli , Kinetics , RNA, Bacterial/chemistry , RNA, Bacterial/genetics , RNA, Bacterial/metabolism , RNA, Transfer/genetics , RNA, Transfer/metabolismABSTRACT
The human mitochondrial tRNALeu(CUN) [hmtRNALeu(CUN)] corresponds to the most abundant codon for leucine in human mitochondrial protein genes. Here, in vitro studies reveal that the U48C substitution in hmtRNALeu(CUN), which corresponds to the pathological T12311C gene mutation, improved the aminoacylation efficiency of hmtRNALeu(CUN). Enzymatic probing suggested a more flexible secondary structure in the wild-type hmtRNALeu(CUN) transcript compared with the U48C mutant. Structural analysis revealed that the flexibility of hmtRNALeu(CUN) facilitates a T-stem slip resulting in two potential tertiary structures. Several rationally designed tRNALeu(CUN) mutants were generated to examine the structural and functional consequences of the T-stem slip. Examination of these hmtRNALeu(CUN) mutants indicated that the T-stem slip governs tRNA accepting activity. These results suggest a novel, self-regulation mechanism of tRNA structure and function.
