| 1. |
- Blomqvist, Maria K., 1975, et al.
(författare)
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High-throughput analysis of sulfatides in cerebrospinal fluid using automated extraction and UPLC-MS/MS
- 2017
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Ingår i: Journal of Lipid Research. - 0022-2275. ; 58:7, s. 1482-1489
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Tidskriftsartikel (refereegranskat)abstract
- Sulfatides (STs) are a group of glycosphingolipids that are highly expressed in brain. Due to their importance for normal brain function and their potential involvement in neurological diseases, development of accurate and sensitive methods for their determination is needed. Here we describe a high-throughput oriented and quantitative method for the determination of STs in cerebrospinal fluid (CSF). The STs were extracted using a fully automated liquid/liquid extraction method and quantified using ultra-performance liquid chromatography coupled to tandem mass spectrometry. With the high sensitivity of the developed method, quantification of 20 ST species from only 100 mu l of CSF was performed. Validation of the method showed that the STs were extracted with high recovery (90%) and could be determined with low inter-and intra-day variation. Our method was applied to a patient cohort of subjects with an Alzheimer's disease biomarker profile. Although the total ST levels were unaltered compared with an age-matched control group, we show that the ratio of hydroxylated/nonhydroxylated STs was increased in the patient cohort. In conclusion, we believe that the fast, sensitive, and accurate method described in this study is a powerful new tool for the determination of STs in clinical as well as preclinical settings.-Blomqvist, M., J. Boren, H. Zetterberg, K. Blennow, J-E. Mansson, and M. Stahlman. High-throughput analysis of sulfatides in cerebrospinal fluid using automated extraction and UPLC-MS/MS.
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| 2. |
- Cansby, Emmelie, 1984, et al.
(författare)
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Targeted Delivery of Stk25 Antisense Oligonucleotides to Hepatocytes Protects Mice Against Nonalcoholic Fatty Liver Disease
- 2019
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Ingår i: CMGH Cellular and Molecular Gastroenterology and Hepatology. - : Elsevier BV. - 2352-345X. ; 7:3, s. 597-618
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims: Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are emerging as leading causes of liver disease worldwide. Currently, no specific pharmacologic therapy is available for NAFLD/NASH, which has been recognized as one of the major unmet medical needs of the 21st century. Our recent studies in genetic mouse models, human cell lines, and well-characterized patient cohorts have identified serine/threonine protein kinase (STK)25 as a critical regulator of hepatic lipid partitioning and NAFLD/NASH. Here, we studied the metabolic benefit of liver-specific STK25 inhibitors on NAFLD development and progression in a mouse model of diet-induced obesity. Methods: We developed a hepatocyte-specific triantennary N-acetylgalactosamine (GalNAc)-conjugated antisense oligonucleotide (ASO) targeting Stk25 and evaluated its effect on NAFLD features in mice after chronic exposure to dietary lipids. Results: We found that systemic administration of hepatocyte-targeting GalNAc-Stk25 ASO in obese mice effectively ameliorated steatosis, inflammatory infiltration, hepatic stellate cell activation, nutritional fibrosis, and hepatocellular damage in the liver compared with mice treated with GalNAc-conjugated nontargeting ASO, without any systemic toxicity or local tolerability concerns. We also observed protection against high-fat-diet–induced hepatic oxidative stress and improved mitochondrial function with Stk25 ASO treatment in mice. Moreover, GalNAc-Stk25 ASO suppressed lipogenic gene expression and acetyl-CoA carboxylase protein abundance in the liver, providing insight into the molecular mechanisms underlying repression of hepatic steatosis. Conclusions: This study provides in vivo nonclinical proof-of-principle for the metabolic benefit of liver-specific inhibition of STK25 in the context of obesity and warrants future investigations to address the therapeutic potential of GalNAc-Stk25 ASO in the prevention and treatment of NAFLD.
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| 3. |
- Chaudhari, Aditi, et al.
(författare)
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ARAP2 promotes GLUT1-mediated basal glucose uptake through regulation of sphingolipid metabolism
- 2016
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Ingår i: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - : Elsevier BV. - 1388-1981. ; 1861:11, s. 1643-1651
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Tidskriftsartikel (refereegranskat)abstract
- Lipid droplet formation, which is driven by triglyceride synthesis, requires several droplet-associated proteins. We identified ARAP2 (an ADP-ribosylation factor 6 GTPase-activating protein) in the lipid droplet proteome of NIH-3T3 cells and showed that knockdown of ARAP2 resulted in decreased lipid droplet formation and triglyceride synthesis. We also showed that ARAP2 knockdown did not affect fatty acid uptake but reduced basal glucose uptake, total levels of the glucose transporter GLUT1, and GLUT1 levels in the plasma membrane and the lipid micro-domain fraction (a specialized plasma membrane domain enriched in sphingolipids). Microarray analysis showed that ARAP2 knockdown altered expression of genes involved in sphingolipid metabolism. Because sphingolipids are known to play a key role in cell signaling, we performed lipidomics to further investigate the relationship between ARAP2 and sphingolipids and potentially identify a link with glucose uptake. We found that ARAP2 knockdown increased glucosylceramide and lactosylceramide levels without affecting ceramide levels, and thus speculated that the rate-limiting enzyme in glycosphingolipid synthesis, namely glucosylceramide synthase (GCS), could be modified by ARAP2. In agreement with our hypothesis, we showed that the activity of GCS was increased by ARAP2 knockdown and reduced by ARAP2 overexpression. Furthermore, pharmacological inhibition of GCS resulted in increases in basal glucose uptake, total GLUT1 levels, triglyceride biosynthesis from glucose, and lipid droplet formation, indicating that the effects of GCS inhibition are the opposite to those resulting from ARAP2 knockdown. Taken together, our data suggest that ARAP2 promotes lipid droplet formation by modifying sphingolipid metabolism through GCS.
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| 4. |
- Fryk, Emanuel, et al.
(författare)
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Microdialysis and proteomics of subcutaneous interstitial fluid reveals increased galectin-1 in type 2 diabetes patients
- 2016
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Ingår i: Metabolism-Clinical and Experimental. - : Elsevier BV. - 0026-0495 .- 1532-8600. ; 65:7, s. 998-1006
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To identify a potential therapeutic target for type 2 diabetes by comparing the subcutaneous interstitial fluid from type 2 diabetes patients and healthy men. Methods. Proteomics was performed on the interstitial fluid of subcutaneous adipose tissue obtained by microdialysis from 7 type 2 diabetes patients and 8 healthy participants. 851 proteins were detected, of which 36 (including galectin-1) showed significantly altered expression in type 2 diabetes. We also measured galectin-1 expression in: (1) adipocytes isolated from adipose tissue biopsies from these participants; (2) subcutaneous adipose tissue of 24 obese participants before, during and after 16 weeks on a very low calorie diet (VLCD); and (3) adipocytes isolated from 6 healthy young participants after 4 weeks on a diet and lifestyle intervention to promote weight gain. We also determined the effect of galectin-1 on glucose uptake in human adipose tissue. Results. Galectin-1 protein levels were elevated in subcutaneous dialysates from type 2 diabetes compared with healthy controls (p < 0.05). In agreement, galectin-1 mRNA expression was increased in adipocytes from the type 2 diabetes patients (p < 0.05). Furthermore, galectin-1 mRNA expression was decreased in adipose tissue after VLCD (p < 0.05) and increased by overfeeding (p < 0.05). Co-incubation of isolated human adipocytes with galectin-1 reduced glucose uptake (p < 0.05) but this was independent of the insulin signal. Conclusion. Proteomics of the interstitial fluid in subcutaneous adipose tissue in vivo identified a novel adipokine, galectin-1, with a potential role in the pathophysiology of type 2 diabetes. (C) 2016 Elsevier Inc. All rights reserved.
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| 5. |
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| 6. |
- Håversen, Liliana, 1963, et al.
(författare)
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Vimentin deficiency in macrophages induces increased oxidative stress and vascular inflammation but attenuates atherosclerosis in mice
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to clarify the role of vimentin, an intermediate filament protein abundantly expressed in activated macrophages and foam cells, in macrophages during atherogenesis. Global gene expression, lipid uptake, ROS, and inflammation were analyzed in bone-marrow derived macrophages from vimentin-deficient (Vim(-/-)) and wild-type (Vim(-/-)) mice. Atherosclerosis was induced in Ldlr(-/-) mice transplanted with a PCSK9 gain-of-function virus. The mice were fed an atherogenic diet for 12-15 weeks. We observed impaired uptake of native LDL but increased uptake of oxLDL in Vim(-/-) macrophages. FACS analysis revealed increased surface expression of the scavenger receptor CD36 on Vim(-/-) macrophages. Vim(-/-) macrophages also displayed increased markers of oxidative stress, activity of the transcription factor NF-kappa B, secretion of proinflammatory cytokines and GLUT1-mediated glucose uptake. Vim(-/- )mice displayed decreased atherogenesis despite increased vascular inflammation and increased CD36 expression on macrophages in two mouse models of atherosclerosis. We demonstrate that vimentin has a strong suppressive effect on oxidative stress and that Vim(-/-) mice display increased vascular inflammation with increased CD36 expression on macrophages despite decreased subendothelial lipid accumulation. Thus, vimentin has a key role in regulating inflammation in macrophages during atherogenesis.
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| 7. |
- Matikainen, N., et al.
(författare)
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Minor contribution of endogenous GLP-1 and GLP-2 to postprandial lipemia in obese men
- 2016
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Context. Glucose and lipids stimulate the gut-hormones glucagon-like peptide (GLP)-1, GLP-2 and glucose-dependent insulinotropic polypeptide (GIP) but the effect of these on human postprandial lipid metabolism is not fully clarified. Objective. To explore the responses of GLP-1, GLP-2 and GIP after a fat-rich meal compared to the same responses after an oral glucose tolerance test (OGTT) and to investigate possible relationships between incretin response and triglyceride-rich lipoprotein (TRL) response to a fat-rich meal. Design. Glucose, insulin, GLP-1, GLP-2 and GIP were measured after an OGTT and after a fat-rich meal in 65 healthy obese (BMI 26.5-40.2 kg/m2) male subjects. Triglycerides (TG), apoB48 and apoB100 in TG-rich lipoproteins (chylomicrons, VLDL1 and VLDL2) were measured after the fat-rich meal. Main Outcome Measures. Postprandial responses (area under the curve, AUC) for glucose, insulin, GLP-1, GLP-2, GIP in plasma, and TG, apoB48 and apoB100 in plasma and TG-rich lipoproteins. Results. The GLP-1, GLP-2 and GIP responses after the fat-rich meal and after the OGTT correlated strongly (r = 0.73, p<0.0001; r = 0.46, p<0.001 and r = 0.69, p<0.001, respectively). Glucose and insulin AUCs were lower, but the AUCs for GLP-1, GLP-2 and GIP were significantly higher after the fat-rich meal than after the OGTT. The peak value for all hormones appeared at 120 minutes after the fat-rich meal, compared to 30 minutes after the OGTT. After the fat-rich meal, the AUCs for GLP-1, GLP-2 and GIP correlated significantly with plasma TG- and apoB48 AUCs but the contribution was very modest. Conclusions. In obese males, GLP-1, GLP-2 and GIP responses to a fat-rich meal are greater than following an OGTT. However, the most important explanatory variable for postprandial TG excursion was fasting triglycerides. The contribution of endogenous GLP-1, GLP-2 and GIP to explaining the variance in postprandial TG excursion was minor. Copyright © 2016 Matikainen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 8. |
- Mobarak, E., et al.
(författare)
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Glucosylceramide modifies the LPS-induced inflammatory response in macrophages and the orientation of the LPS/TLR4 complex in silico
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Toll-like receptor 4 (TLR4) is activated by bacterial lipopolysaccharide (LPS), which drives the production of proinflammatory cytokines. Earlier studies have indicated that cholesterol-and glycosphingolipid-rich subregions of the plasma membrane (lipid domains) are important for TLR4-mediated signaling. We report that inhibition of glucosylceramide (GluCer) synthase, which resulted in decreased concentrations of the glycosphingolipid GluCer in lipid domains, reduced the LPS-induced inflammatory response in both mouse and human macrophages. Atomistic molecular dynamics simulations of the TLR4 dimer complex (with and without LPS in its MD-2 binding pockets) in membranes (in the presence and absence of GluCer) showed that: (1) LPS induced a tilted orientation of TLR4 and increased dimer integrity; (2) GluCer did not affect the integrity of the LPS/TLR4 dimer but reduced the LPS-induced tilt; and (3) GluCer increased electrostatic interactions between the membrane and the TLR4 extracellular domain, which could potentially modulate the tilt. We also showed that GCS inhibition reduced the interaction between TLR4 and the intracellular adaptor protein Mal. We conclude that the GluCer-induced effects on LPS/TLR4 orientation may influence the signaling capabilities of the LPS/TLR4 complex by affecting its interaction with downstream signaling proteins.
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| 9. |
- Nielsen, Jens B, 1962, et al.
(författare)
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Improving the economics of NASH/NAFLD treatment through the use of systems biology
- 2017
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Ingår i: Drug Discovery Today. - : Elsevier BV. - 1359-6446 .- 1878-5832. ; 22:10, s. 1532-1538
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Tidskriftsartikel (refereegranskat)abstract
- Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease (NAFLD). We surveyed NASH therapies currently in development, and found a significant variety of targets and approaches. Evaluation and clinical testing of these targets is an expensive and time-consuming process. Systems biology approaches could enable the quantitative evaluation of the likely efficacy and safety of different targets. This motivated our review of recent systems biology studies that focus on the identification of targets and development of effective treatments for NASH. We discuss the potential broader use of genome-scale metabolic models and integrated networks in the validation of drug targets, which could facilitate more productive and efficient drug development decisions for the treatment of NASH.
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| 10. |
- Novakova, Lenka, 1984, et al.
(författare)
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Sulfatide isoform pattern in cerebrospinal fluid discriminates progressive MS from relapsing-remitting MS
- 2018
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Ingår i: Journal of Neurochemistry. - : Wiley. - 0022-3042. ; 146:3, s. 322-332
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Tidskriftsartikel (refereegranskat)abstract
- Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). Several biomarkers including proteins and lipids have been reported in MS cerebrospinal fluid (CSF), reflecting different aspects of the pathophysiology particularly of relapsing-remitting MS (RRMS). Sulfatide, abundant in the myelin sheath and a proposed target for autoimmune attack in MS, has been reported altered in MS CSF. Here, we investigated the potential of CSF sulfatide and its isoforms as biomarkers in MS. A highly sensitive and quantitative mass spectrometry method was employed to determine levels of sulfatide isoforms in CSF from RRMS and progressive MS (PMS) patients, and healthy donors (HD). We demonstrate that levels of total CSF sulfatide and C24:1, C26:1, and C26:1-OH isoforms were significantly increased in PMS compared with RRMS patients and HD, while C23:0-OH was significantly decreased in CSF from PMS patients compared to the other two groups. Multivariate discriminant analysis showed that CSF sulfatide isoform pattern in PMS patients was distinct and non-overlapping with that of RRMS patients and HD. Sulfatide levels did not correlate with tested biomarkers or clinical parameters. The results suggest that CSF sulfatide isoform levels may be used to discriminate the phenotype ofMS and might play a role in the progression of the disease.
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