Fibroblast growth factor 21 alleviates diabetes-induced cognitive decline.

Diabetes mellitus (DM) causes damage to the central nervous system, resulting in cognitive impairment. Fibroblast growth factor 21 (FGF21) exhibits the potential to alleviate neurodegeneration. However, the therapeutic effect of intracerebroventricular (i.c.v) FGF21 infusion on diabetes-induced cognitive decline (DICD) and its potential mechanisms remain unclear. In this study, the impact of FGF21 on DICD was explored, and 1H nuclear magnetic resonance (NMR)-based metabolomics plus 13C NMR spectroscopy in combine with intravenous [1-13C]-glucose infusion were used to investigate the underlying metabolic mechanism. Results revealed that i.c.v FGF21 infusion effectively improved learning and memory performance of DICD mice; neuron loss and apoptosis in hippocampus and cortex were significantly blocked, suggesting a potential neuroprotective role of FGF21 in DICD. Metabolomics results revealed that FGF21 modulated DICD metabolic alterations related to glucose and neurotransmitter metabolism, which are characterized by distinct recovered enrichment of [3-13C]-lactate, [3-13C]-aspartate, [4-13C]-glutamine, [3-13C]-glutamine, [4-13C]-glutamate, and [4-13C]- γ-aminobutyric acid (GABA) from [1-13C]-glucose. Moreover, diabetes-induced neuron injury and metabolic dysfunctions might be mediated by PI3K/AKT/GSK-3ß signaling pathway inactivation in the hippocampus and cortex, which were activated by i.c.v injection of FGF21. These findings indicate that i.c.v FGF21 infusion exerts its neuroprotective effect on DICD by remodeling cerebral glucose and neurotransmitter metabolism by activating the PI3K/AKT/GSK-3ß signaling pathway.

Comparison of dual mTORC1/2 inhibitor AZD8055 and mTORC1 inhibitor rapamycin on the metabolism of breast cancer cells using proton nuclear magnetic resonance spectroscopy metabolomics.

Dual mTORC1/2 inhibitors may be more effective than mTORC1 inhibitor rapamycin. Nevertheless, their metabolic effects on breast cancer cells have not been reported. We compared the anti-proliferative capacity of rapamycin and a novel mTORC1/2 dual inhibitor (AZD8055) in two breast cancer cell lines (MDA-MB-231 and MDA-MB-453) and analyzed their metabolic effects using proton nuclear magnetic resonance (1H NMR) spectroscopy-based metabolomics. We found that AZD8055 more strongly inhibited breast cancer cell proliferation than rapamycin. The half-inhibitory concentration of AZD8055 in breast cancer cells was almost one-tenth that of rapamycin. We identified 22 and 23 metabolites from the 1H NMR spectra of MDA-MB-231 and MDA-MB-453 cells. The patterns of AZD8055- and rapamycin-treated breast cancer cells differed significantly; we then selected the metabolites that contributed to these differences. For inhibiting glycolysis and reducing glucose consumption, AZD8055 was likely to be more potent than rapamycin. For amino acids metabolism, although AZD8055 has a broad effect as rapamycin, their effects in degrees were not exactly the same. AZD8055 and rapamycin displayed cell-specific metabolic effects on breast cancer cells, a finding that deserves further study. These findings help fill the knowledge gap concerning dual mTORC1/2 inhibitors and provide a theoretical basis for their development.

Balancing metabolome coverage and reproducibility for untargeted NMR-based metabolic profiling in tissue samples through mixture design methods.

Untargeted metabolomics attempts to acquire a comprehensive and reproducible set of small-molecule metabolites in biological systems. However, metabolite extraction method significantly affects the quality of metabolomics data. In the present study, we calculated the number of peaks (NP) and coefficient of variation (CV) to reflect metabolome coverage and reproducibility in untargeted NMR-based metabolic profiling of tissue samples in rats under different methanol/chloroform/water (MCW) extraction conditions. Different MCW extractions expectedly generated diverse characteristics of metabolome. Moreover, the classic MCW method revealed tissue-specific differences in the NP and CV values. To obtain high-quality metabolomics data, therefore, we used mixture design methods to optimize the MCW extraction strategy by maximizing the NP value and minimizing the CV value in each tissue sample. Results show that the optimal formulations of MCW extraction were 2:2:8 (ml/mg tissue) for brain sample, 2:4:6 (ml/mg tissue) for heart sample, 1.3:2:8.7 (ml/mg tissue) for liver sample, 4:2:6 (ml/mg tissue) for kidney sample, 2:3:7 (ml/mg tissue) for muscle sample, and 2:4:6 (ml/mg tissue) for pancreas sample. Therefore, these findings demonstrate that different tissue samples need a specific optimal extraction condition for balancing metabolome coverage and reproducibility in the untargeted metabolomics study. Mixture design method is an effective tool to optimize metabolite extraction strategy for tissue samples. Graphical abstract ᅟ.

[Effects of Mijiandao suppository on intestinal laxation in rats and its mechanisms].

Objective: To investigate the effects of Mijian Daotong Bowel Suppository (MJDs) on the compound diphenoxylate induced constipation model of male rats and its mechanisms. Methods: Sixty SD male rats were randomly divided into blank group, model group, positive group and MJDs group. The constipation model was established by using compound diphenoxylate gavage. The rats in blank group and model group were treated with saline by enema, the rats in positive group and MJDs group were given Kaisailu and honey decoction laxative suppository by enema, respectively, once a day for 10 days. The body weight, fecal water content, gastric emptying rate (GER) and carbon ink propulsion rate (CIPR) of rats were observed during modeling and administration. The effects of MJDs on the pathological changes of colon tissue in constipation rats were investigated by hematoxylin-eosin (HE) staining. The effect of MJDs on 5-hydroxytryptamine (5-HT) in the colon of constipation rats was investigated by ELISA kit. The effects of MJDs on the expressions of aquaporins 3 (AQP3) and aquaporins 4 (AQP4) in the colon of constipation rats were detected by immunohistochemistry. Results: After 10 days of administration, compared with the blank group, the body weight, fecal water content, carbon ink propulsion rate and colon 5-HT content in the model group were decreased significantly, while the expression levels of AQP3 and AQP4 in the colon were increased significantly (P＜0.05, P＜0.01). Compared with the model group, the fecal water content and colon 5-HT content in the positive group were increased significantly, and the expressions of AQP3 and AQP4 in the colon were decreased significantly. The body weight, fecal water content and colon 5-HT content in the MJDs group were increased significantly, and the expressions of AQP3 and AQP4 was decreased significantly (P＜0.05, P＜0.01). Compared with the positive group, the fecal water content of the MJDs group was decreased significantly, and the expressions of AQP3 and AQP4 in the colon of the MJDs group was decreased significantly (P＜0.05, P＜0.01). Gastric emptying rate was not statistically significant difference between the groups. Conclusion: MJDs has good therapeutic effects on constipation, and its mechanisms may be related to up-regulating the content of 5-HT in the colon and down-regulating the expressions of AQP3 and AQP4 in the colon.