| 1. |
- Shi, Yuanping, et al.
(författare)
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Comprehensive lipidomics in apoM−/− mice reveals an overall state of metabolic distress and attenuated hepatic lipid secretion into the circulation
- 2020
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Ingår i: Journal of Genetics and Genomics. - : Elsevier BV. - 1673-8527. ; 47:9, s. 523-534
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (apoM) participates in both high-density lipoprotein and cholesterol metabolism. Little is known about how apoM affects lipid composition of the liver and serum. In this study, we systemically investigated the effects of apoM on liver and plasma lipidomes and how apoM participates in lipid cycling, via apoM knockout in mice and the human SMMC-7721 cell line. We used integrated mass spectrometry–based lipidomics approaches to semiquantify more than 600 lipid species from various lipid classes, which include free fatty acids, glycerolipids, phospholipids, sphingolipids, glycosphingolipids, cholesterol, and cholesteryl esters (CEs), in apoM−/− mouse. Hepatic accumulation of neutral lipids, including CEs, triacylglycerols, and diacylglycerols, was observed in apoM−/− mice; while serum lipidomic analyses showed that, in contrast to the liver, the overall levels of CEs and saturated/monounsaturated fatty acids were markedly diminished. Furthermore, the level of ApoB-100 was dramatically increased in the liver, whereas significant reductions in both ApoB-100 and low-density lipoprotein (LDL) cholesterol were observed in the serum of apoM−/− mice, which indicated attenuated hepatic LDL secretion into the circulation. Lipid profiles and proinflammatory cytokine levels indicated that apoM−/− leads to hepatic steatosis and an overall state of metabolic distress. Taken together, these results revealed that apoM knockout leads to hepatic steatosis, impaired lipid secretion, and an overall state of metabolic distress.
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| 2. |
- Yao, Shuang, et al.
(författare)
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Insulin resistance in apolipoprotein M knockout mice is mediated by the protein kinase akt signaling pathway
- 2020
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Ingår i: Endocrine, Metabolic & Immune Disorders - Drug Targets. - : Bentham Science Publishers Ltd.. - 1871-5303. ; 20:5, s. 771-780
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Tidskriftsartikel (refereegranskat)abstract
- Background: Previous clinical studies have suggested that apolipoprotein M (apoM) is involved in glucose metabolism and plays a causative role in insulin sensitivity. Objective: The potential mechanism of apoM on modulating glucose homeostasis is explored and differentially expressed genes are analyzed by employing ApoM deficient (ApoM-/-) and wild type (WT) mice. Methods: The metabolism of glucose in the hepatic tissues of high-fat diet ApoM-/- and WT mice was measured by a glycomics approach. Bioinformatic analysis was applied for analyzing the levels of differentially expressed mRNAs in the liver tissues of these mice. The insulin sensitivity of ApoM-/- and WT mice was compared using the insulin tolerance test and the phosphorylation levels of protein kinase Akt (AKT) and insulin stimulation in different tissues were examined by Western blot. Results: The majority of the hepatic glucose metabolites exhibited lower concentration levels in the ApoM-/- mice compared with those of the WT mice. Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that ApoM deficiency affected the genes associated with the metabolism of glucose. The insulin tolerance test suggested that insulin sensitivity was impaired in ApoM-/- mice. The phosphorylation levels of AKT in muscle and adipose tissues of ApoM-/- mice were significantly diminished in response to insulin stimulation compared with those noted in WT mice. Conclusion: ApoM deficiency led to the disorders of glucose metabolism and altered genes related to glucose metabolism in mice liver. In vivo data indicated that apoM might augment insulin sensitivity by AKT-dependent mechanism.
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| 3. |
- Yu, Yang, et al.
(författare)
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Apolipoprotein M overexpression through adeno-associated virus gene transfer improves insulin secretion and insulin sensitivity in Goto-Kakizaki rats
- 2020
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Ingår i: Journal of Diabetes Investigation. - : Wiley. - 2040-1116 .- 2040-1124. ; 11:5, s. 1150-1158
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Tidskriftsartikel (refereegranskat)abstract
- Aims/Objective: The development of type 2 diabetes is a result of insulin resistance in various tissues, including skeletal muscle and liver. Apolipoprotein M (ApoM) plays an important role in the function of high-density lipoprotein, and also affects hepatic lipid and glucose metabolism. In this study, we aimed to investigate whether ApoM overexpression modulates glucose metabolism and improves insulin sensitivity. Materials and Methods: The Goto-Kakizaki (GK) rats were transfected with adeno-associated virus (AAV) encoding rat ApoM gene or control blank. The oral glucose tolerance test (OGTT) and hyperinsulinemic-euglycemic clamp (HEC) experiment were used to assess the insulin sensitivity of GK rats. Results: The results show that ApoM messenger ribonucleic acid and protein were significantly overexpressed in the pancreatic tissues. Overexpression of ApoM decreased fasting blood glucose and random blood glucose, improved glucose tolerance, and increased bodyweight and insulin levels in GK rats. The glucose infusion rate of rats in the AAV encoding rat ApoM gene group during HEC test was 1.04-, 1.23- and 1.95-fold higher than that in the AAV control blank group at 1–3 weeks after injection of AAV, respectively. A Wes-ProteinSimple assay and quantification was carried out to assess phosphorylated protein kinase B/protein kinase B protein levels in the muscle tissues of ApoM-overexpressing GK rats, and they were found to be higher than those of the control group at the seventh week after AAV injection. Conclusions: ApoM overexpression through adeno-associated virus gene transfer might improve insulin secretion and insulin sensitivity in GK rats.
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| 4. |
- Zhou, Weihua, et al.
(författare)
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Purine metabolism regulates DNA repair and therapy resistance in glioblastoma
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Intratumoral genomic heterogeneity in glioblastoma (GBM) is a barrier to overcoming therapy resistance. Treatments that are effective independent of genotype are urgently needed. By correlating intracellular metabolite levels with radiation resistance across dozens of genomically-distinct models of GBM, we find that purine metabolites, especially guanylates, strongly correlate with radiation resistance. Inhibiting GTP synthesis radiosensitizes GBM cells and patient-derived neurospheres by impairing DNA repair. Likewise, administration of exogenous purine nucleosides protects sensitive GBM models from radiation by promoting DNA repair. Neither modulating pyrimidine metabolism nor purine salvage has similar effects. An FDA-approved inhibitor of GTP synthesis potentiates the effects of radiation in flank and orthotopic patient-derived xenograft models of GBM. High expression of the rate-limiting enzyme of de novo GTP synthesis is associated with shorter survival in GBM patients. These findings indicate that inhibiting purine synthesis may be a promising strategy to overcome therapy resistance in this genomically heterogeneous disease.
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