| 1. |
- Abels, Mia, et al.
(författare)
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CART is overexpressed in human type 2 diabetic islets and inhibits glucagon secretion and increases insulin secretion
- 2016
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 59:9, s. 1928-1937
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis Insufficient insulin release and hyperglucagonaemia are culprits in type 2 diabetes. Cocaine- and amphetamine-regulated transcript (CART, encoded by Cartpt) affects islet hormone secretion and beta cell survival in vitro in rats, and Cart(-/-) mice have diminished insulin secretion. We aimed to test if CART is differentially regulated in human type 2 diabetic islets and if CART affects insulin and glucagon secretion in vitro in humans and in vivo in mice. Methods CART expression was assessed in human type 2 diabetic and non-diabetic control pancreases and rodent models of diabetes. Insulin and glucagon secretion was examined in isolated islets and in vivo in mice. Ca2+ oscillation patterns and exocytosis were studied in mouse islets. Results We report an important role of CART in human islet function and glucose homeostasis in mice. CART was found to be expressed in human alpha and beta cells and in a subpopulation of mouse beta cells. Notably, CART expression was several fold higher in islets of type 2 diabetic humans and rodents. CART increased insulin secretion in vivo in mice and in human and mouse islets. Furthermore, CART increased beta cell exocytosis, altered the glucose-induced Ca2+ signalling pattern in mouse islets from fast to slow oscillations and improved synchronisation of the oscillations between different islet regions. Finally, CART reduced glucagon secretion in human and mouse islets, as well as in vivo in mice via diminished alpha cell exocytosis. Conclusions/interpretation We conclude that CART is a regulator of glucose homeostasis and could play an important role in the pathophysiology of type 2 diabetes. Based on the ability of CART to increase insulin secretion and reduce glucagon secretion, CART-based agents could be a therapeutic modality in type 2 diabetes.
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| 2. |
- Bryl-Górecka, Paulina, et al.
(författare)
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Bilberry Supplementation after Myocardial Infarction Decreases Microvesicles in Blood and Affects Endothelial Vesiculation
- 2020
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Ingår i: Molecular Nutrition & Food Research. - : Wiley-VCH Verlagsgesellschaft. - 1613-4125 .- 1613-4133. ; 64:20
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Tidskriftsartikel (refereegranskat)abstract
- Scope: Diet rich in bilberries is considered cardioprotective, but the mechanisms of action are poorly understood. Cardiovascular disease is characterized by increased proatherogenic status and high levels of circulating microvesicles (MVs). In an open-label study patients with myocardial infarction receive an 8 week dietary supplementation with bilberry extract (BE). The effect of BE on patient MV levels and its influence on endothelial vesiculation in vitro is investigated.Methods and results: MVs are captured with acoustic trapping and platelet-derived MVs (PMVs), as well as endothelial-derived MVs (EMVs) are quantified with flow cytometry. The in vitro effect of BE on endothelial extracellular vesicle (EV) release is examined using endothelial cells and calcein staining. The mechanisms of BE influence on vesiculation pathways are studied by Western blot and qRT-PCR. Supplementation with BE decreased both PMVs and EMVs. Furthermore, BE reduced endothelial EV release, Akt phosphorylation, and vesiculation-related gene transcription. It also protects the cells from P2X(7)-induced EV release and increase in vesiculation-related gene expression.Conclusion: BE supplementation improves the MV profile in patient blood and reduces endothelial vesiculation through several molecular mechanisms related to the P2X(7)receptor. The findings provide new insight into the cardioprotective effects of bilberries.
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| 3. |
- Bryl-Górecka, Paulina, et al.
(författare)
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Effect of exercise on the plasma vesicular proteome : A methodological study comparing acoustic trapping and centrifugation
- 2018
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 18:20, s. 3101-3111
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular vesicles (EVs) are a heterogeneous group of actively released vesicles originating from a wide range of cell types. Characterization of these EVs and their proteomes in the human plasma provides a novel approach in clinical diagnostics, as they reflect physiological and pathological states. However, EV isolation is technically challenging with the current methods having several disadvantages, requiring large sample volumes, and resulting in loss of sample and EV integrity. Here, we use an alternative, non-contact method based on a microscale acoustic standing wave technology. Improved coupling of the acoustic resonator increased the EV recovery from 30% in earlier reports to 80%, also displaying long term stability between experiment days. We report a pilot study, with 20 subjects who underwent physical exercise. Plasma samples were obtained before and 1 h after the workout. Acoustic trapping was compared to a standard high-speed centrifugation protocol, and the method was validated by flow cytometry (FCM). To monitor the device stability, the pooled frozen plasma from volunteers was used as an internal control. A key finding from the FCM analysis was a decrease in CD62E+ (E-selectin) EVs 1 h after exercise that was consistent for both methods. Furthermore, we report the first data that analyse differential EV protein expression before and after physical exercise. Olink-based proteomic analysis showed 54 significantly changed proteins in the EV fraction in response to physical exercise, whereas the EV-free plasma proteome only displayed four differentially regulated proteins, thus underlining an important role of these vesicles in cellular communication, and their potential as plasma derived biomarkers. We conclude that acoustic trapping offers a fast and efficient method comparable with high-speed centrifugation protocols. Further, it has the advantage of using smaller sample volumes (12.5 μL) and rapid contact-free separation with higher yield, and can thus pave the way for future clinical EV-based diagnostics.
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| 4. |
- Gidlöf, Olof, et al.
(författare)
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Extracellular Uridine Triphosphate and Adenosine Triphosphate Attenuate Endothelial Inflammation through miR-22-Mediated ICAM-1 Inhibition.
- 2015
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 52:2, s. 71-80
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Tidskriftsartikel (refereegranskat)abstract
- Adenosine and uridine triphosphate (ATP and UTP) can act as extracellular signalling molecules, playing important roles in vascular biology and disease. ATP and UTP acting via the P2Y2-receptor have, for example, been shown to regulate endothelial dilatation, inflammation and angiogenesis. MicroRNAs (miRNAs), a class of regulatory, short, non-coding RNAs, have been shown to be important regulators of these biological processes. In this study, we used RNA deep-sequencing to explore changes in miRNA expression in the human microvascular endothelial cell line HMEC-1 upon UTP treatment. The expression of miR-22, which we have previously shown to target ICAM-1 mRNA in HMEC-1, increased significantly after stimulation. Up-regulation of miR-22 and down-regulation of cell surface ICAM-1 were confirmed with qRT-PCR and flow cytometry, respectively. siRNA-mediated knockdown of the P2Y2-receptor abolished the effect of UTP on miR-22 transcription. Leukocyte adhesion was significantly inhibited in HMEC-1 following miR-22 overexpression and treatment with UTP/ATP. In conclusion, extracellular UTP and ATP can attenuate ICAM-1 expression and leukocyte adhesion in endothelial cells through miR-22. © 2015 S. Karger AG, Basel.
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| 5. |
- Grossi, Mario, et al.
(författare)
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Vascular smooth muscle cell proliferation depends on caveolin-1-regulated polyamine uptake
- 2014
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Ingår i: Bioscience Reports. - 0144-8463. ; 34, s. 729-741
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Tidskriftsartikel (refereegranskat)abstract
- Much evidence highlights the importance of polyamines for VSMC (vascular smooth muscle cell) proliferation and migration. Cav-1 (caveolin-1) was recently reported to regulate polyamine uptake in intestinal epithelial cells. The aim of the present study was to assess the importance of Cav-1 for VSMC polyamine uptake and its impact on cell proliferation and migration. Cav-1 KO (knockout) mouse aortic cells showed increased polyamine uptake and elevated proliferation and migration compared with WT (wild-type) cells. Both Cav-1 KO and WT cells expressed the smooth muscle differentiation markers SM22 and calponin. Cell-cycle phase distribution analysis revealed a higher proportion of Cav-1 KO than WT cells in the S phase. Cav-1 KO cells were hyper-proliferative in the presence but not in the absence of extracellular polyamines, and, moreover, supplementation with exogenous polyamines promoted proliferation in Cav-1 KO but not in WT cells. Expression of the solute carrier transporters Slc7a1 and Slc43a1 was higher in Cav-1 KO than in WT cells. ODC (ornithine decarboxylase) protein and mRNA expression as well as ODC activity were similar in Cav-1 KO and WT cells showing unaltered synthesis of polyamines in Cav-1 KO cells. Cav-1 was reduced in migrating cells in vitro and in carotid lesions in vivo. Our data show that Cav-1 negatively regulates VSMC polyamine uptake and that the proliferative advantage of Cav-1 KO cells is critically dependent on polyamine uptake. We provide proof-of-principle for targeting Cav-1-regulated polyamine uptake as a strategy to fight unwanted VSMC proliferation as observed in restenosis.
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| 6. |
- Nagorny, Cecilia, et al.
(författare)
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Distribution of melatonin receptors in murine pancreatic islets.
- 2011
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Ingår i: Journal of Pineal Research. - 1600-079X. ; 50, s. 412-417
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Tidskriftsartikel (refereegranskat)abstract
- Melatonin has multiple receptor-dependent and receptor-independent functions. At the cell membrane, melatonin interacts with its receptors MT1 and MT2, which are expressed in numerous tissues. Genome-wide association studies have recently shown that the MTNR1B/MT2 receptor may be involved in the pathogenesis of type 2 diabetes mellitus. In line with these findings, expression of melatonin receptors has been shown in mouse, rat, and human pancreatic islets. MT1 and MT2 are G-protein-coupled receptors and are proposed to exert inhibitory effects on insulin secretion. Here, we show by immunocytochemistry that these membrane melatonin receptors have distinct locations in the mouse islet. MT1 is expressed in α-cells while MT2 is located to the β-cells. These findings help to unravel the complex machinery underlying melatonin's role in the regulation of islet function.
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| 7. |
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| 8. |
- Rezeli, Melinda, et al.
(författare)
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Comparative Proteomic Analysis of Extracellular Vesicles Isolated by Acoustic Trapping or Differential Centrifugation
- 2016
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 88:17, s. 8577-8586
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular vesicles (ECVs), including microparticles and exosomes, are submicrometer membrane vesicles released by diverse cell types upon activation or stress. Circulating ECVs are potential reservoirs of disease biomarkers, and the complexity of these vesicles is significantly lower compared to their source, blood plasma, which makes ECV-based biomarker studies more promising. Proteomic profiling of ECVs is important not only to discover new diagnostic or prognostic markers but also to understand their roles in biological function. In the current study, we investigated the protein composition of plasma-derived ECVs isolated by acoustic seed trapping. Additionally, the protein composition of ECVs isolated with acoustic trapping was compared to that isolated with a conventional differential centrifugation protocol. Finally, the proteome of ECVs originating from ST-elevation myocardial infarction patients was compared with that of healthy controls using label-free LC-MS quantification. The acoustic trapping platform allows rapid and automated preparation of ECVs from small sample volumes, which are therefore well-suited for biobank repositories. We found that the protein composition of trapped ECVs is very similar to that isolated by the conventional differential centrifugation method.
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| 9. |
- Riva, Matteo, et al.
(författare)
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Nesfatin-1 stimulates glucagon and insulin secretion and beta cell NUCB2 is reduced in human type 2 diabetic subjects.
- 2011
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Ingår i: Cell and Tissue Research. - : Springer Science and Business Media LLC. - 1432-0878 .- 0302-766X. ; 346, s. 393-405
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Tidskriftsartikel (refereegranskat)abstract
- Nesfatin-1 is a novel anorexigenic regulatory peptide. The peptide is the N-terminal part of nucleobindin 2 (NUCB2) and is expressed in brain areas regulating feeding. Outside the brain, nesfatin-1 expression has been reported in adipocytes, gastric endocrine cells and islet cells. We studied NUCB2 expression in human and rodent islets using immunocytochemistry, in situ hybridization and western blot. Furthermore, we investigated the potential influence of nesfatin-1 on secretion of insulin and glucagon in vitro and in vivo in mice and in INS-1 (832/13) cells. The impact of type 2 diabetes (T2D) and glucolipotoxicity on NUCB2 gene expression in human islets and its relationship to insulin secretory capacity and islet gene expression was studied using microarray. Nesfatin-1 immunoreactivity (IR) was abundant in human and rodent beta cells but absent in alpha, delta, PP and ghrelin cells. Importantly, in situ hybridization showed that NUCB2 mRNA is expressed in human and rat islets. Western blot analysis showed that nesfatin-1 IR represented full length NUCB2 in rodent islets. Human islet NUCB2 mRNA was reduced in T2D subjects but upregulated after culture in glucolipotoxic conditions. Furthermore, a positive correlation between NUCB2 and glucagon and insulin gene expression, as well as insulin secretory capacity, was evident. Nesfatin-1 enhanced glucagon secretion but had no effect on insulin secretion from mouse islets or INS-1 (832/13) cells. On the other hand, nesfatin-1 caused a small increase in insulin secretion and reduced glucose during IVGTT in mice. We conclude that nesfatin-1 is a novel glucagon-stimulatory peptide expressed in the beta cell and that its expression is decreased in T2D islets.
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| 10. |
- Sathanoori, Ramasri
(författare)
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A MATTER OF NUTRIENT EXCESS AND SHEAR STRESS
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The metabolic syndrome is a clustering of several risk factors associated with diabetes and cardiovascular disease. Diabetes is a global problem with 90% of patients suffering from type 2 diabetes (T2D), which is attributable to various factors including genetic predispositions and lifestyle. In T2D, there is a reduction in β cell mass and function, and impaired glucose homeostasis. It is often associated with insulin resistance in target tissues and has a profound influence on vascular health. This, thesis investigates the novel role of cocaine and amphetamine regulated transcript (CART) in the pancreatic β cells and purinergic signaling mechanisms in the vascular endothelial cells. Using rat pancreatic clonal β cell lines (INS-1 832/13) and rat islets, we provide evidence for a novel role of CART in β cell survival and proliferation. Exogenous addition of CART 55-102 attenuated glucotoxicity-induced β cell death. This effect of CART was likely due to the activation of signaling molecules important for cell survival, namely, CREB, IRS-2, PKB, FoxO1, p44/42-MAPK, and p90RSK. Furthermore, the pharmacological inhibition of the kinases blocked the proliferative effect of CART on β cells. In conclusion, CART 55-102 protects β cells against glucotoxicity and promotes proliferation and may thereby contribute to the preservation of β cell mass. Physical inactivity and metabolic risk factors together form a continuum that over time negatively affects endothelial function. The vascular endothelium is exposed to fluid shear stress from flowing blood and maintains vascular homeostasis. The resident endothelial cells express a repertoire of specialized purinergic receptors that respond to extracellular nucleotides mediating various physiological responses. In human vascular endothelial cells, both ATPγS and shear stress increased KLF2, a transcription factor important for atheroprotection, in part via the P2X4 receptor. Additionally, shear stress-induced endothelial cell alignment and cytoskeletal remodeling, as seen in atheroprotective regions of the vascular tree, was found to be P2Y2 receptor-dependent. Using pharmacological inhibitors of P2X7 and P2X4, we observed differential effects of these receptors in inhibiting inflammatory genes, reactive oxygen species, and leukocyte adhesion in endothelial cells exposed to high glucose and palmitate. In addition, we demonstrate a novel role of UTP and ATP in regulating miR-22 transcription that inhibits ICAM-1 and leukocyte-endothelial adhesion, an effect possibly mediated by P2Y2 receptors. In conclusion, this thesis provides a molecular basis for treatment strategies, albeit at a cellular level, aiming at (i) preserving β cell mass and function and (ii) enhancing vascular health that range from lifestyle interventions to specific pharmacological therapies.
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