| 1. |
- Andersson, Linda, 1973, et al.
(författare)
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Glucosylceramide synthase deficiency in the heart compromises β1-adrenergic receptor trafficking
- 2021
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Ingår i: European Heart Journal. - : Oxford University Press. - 0195-668X .- 1522-9645. ; 42:43, s. 4481-4492
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Cardiac injury and remodelling are associated with the rearrangement of cardiac lipids. Glycosphingolipids are membrane lipids that are important for cellular structure and function, and cardiac dysfunction is a characteristic of rare monogenic diseases with defects in glycosphingolipid synthesis and turnover. However, it is not known how cardiac glycosphingolipids regulate cellular processes in the heart. The aim of this study is to determine the role of cardiac glycosphingolipids in heart function.METHODS AND RESULTS: Using human myocardial biopsies, we showed that the glycosphingolipids glucosylceramide and lactosylceramide are present at very low levels in non-ischaemic human heart with normal function and are elevated during remodelling. Similar results were observed in mouse models of cardiac remodelling. We also generated mice with cardiomyocyte-specific deficiency in Ugcg, the gene encoding glucosylceramide synthase (hUgcg-/- mice). In 9- to 10-week-old hUgcg-/- mice, contractile capacity in response to dobutamine stress was reduced. Older hUgcg-/- mice developed severe heart failure and left ventricular dilatation even under baseline conditions and died prematurely. Using RNA-seq and cell culture models, we showed defective endolysosomal retrograde trafficking and autophagy in Ugcg-deficient cardiomyocytes. We also showed that responsiveness to β-adrenergic stimulation was reduced in cardiomyocytes from hUgcg-/- mice and that Ugcg knockdown suppressed the internalization and trafficking of β1-adrenergic receptors.CONCLUSIONS: Our findings suggest that cardiac glycosphingolipids are required to maintain β-adrenergic signalling and contractile capacity in cardiomyocytes and to preserve normal heart function.
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| 2. |
- Kijani, Siavash, et al.
(författare)
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Filter-Dense Multicolor Microscopy
- 2015
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Immunofluorescence microscopy is a unique method to reveal the spatial location of proteins in tissues and cells. By combining antibodies that are labeled with different fluorochromes, the location of several proteins can simultaneously be visualized in one sample. However, because of the risk of bleed-through signals between fluorochromes, standard multicolor microscopy is restricted to a maximum of four fluorescence channels, including one for nuclei staining. This is not always enough to address common scientific questions. In particular, the use of a rapidly increasing number of marker proteins to classify functionally distinct cell populations and diseased tissues emphasizes the need for more complex multistainings. Hence, multicolor microscopy should ideally offer more channels to meet the current needs in biomedical science. Here we present an enhanced multi-fluorescence setup, which we call Filter-Dense Multicolor Microscopy (FDMM). FDMM is based on condensed filter sets that are more specific for each fluorochrome and allow a more economic use of the light spectrum. FDMM allows at least six independent fluorescence channels and can be applied to any standard fluorescence microscope without changing any operative procedures for the user. In the present study, we demonstrate an FDMM setup of six channels that includes the most commonly used fluorochromes for histology. We show that the FDMM setup is specific and robust, and we apply the technique on typical biological questions that require more than four fluorescence microscope channels.
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| 3. |
- Krishnaswamy, Jayendra Kumar, et al.
(författare)
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Migratory CD11b+ conventional dendritic cells induce T follicular helper cell-dependent antibody responses.
- 2017
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Ingår i: Science immunology. - : American Association for the Advancement of Science (AAAS). - 2470-9468. ; 2:18
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Tidskriftsartikel (refereegranskat)abstract
- T follicular helper (Tfh) cells are a subset of CD4+ T cells that promote antibody production during vaccination. Conventional dendritic cells (cDCs) efficiently prime Tfh cells; however, conclusions regarding which cDC instructs Tfh cell differentiation have differed between recent studies. We found that these discrepancies might exist because of the unusual sites used for immunization in murine models, which differentially bias which DC subsets access antigen. We used intranasal immunization as a physiologically relevant route of exposure that delivers antigen to all tissue DC subsets. Using a combination of mice in which the function of individual DC subsets is impaired and different antigen formulations, we determined that CD11b+ migratory type 2 cDCs (cDC2s) are necessary and sufficient for Tfh induction. DC-specific deletion of the guanine nucleotide exchange factor DOCK8 resulted in an isolated loss of CD11b+ cDC2, but not CD103+ cDC1, migration to lung-draining lymph nodes. Impaired cDC2 migration or development in DC-specific Dock8 or Irf4 knockout mice, respectively, led to reduced Tfh cell priming, whereas loss of CD103+ cDC1s in Batf3-/- mice did not. Loss of cDC2-dependent Tfh cell priming impaired antibody-mediated protection from live influenza virus challenge. We show that migratory cDC2s uniquely carry antigen into the subanatomic regions of the lymph node where Tfh cell priming occurs-the T-B border. This work identifies the DC subset responsible for Tfh cell-dependent antibody responses, particularly when antigen dose is limiting or is encountered at a mucosal site, which could ultimately inform the formulation and delivery of vaccines.
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| 4. |
- Levin, Malin, 1973, et al.
(författare)
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Rip2 deficiency leads to increased atherosclerosis despite decreased inflammation.
- 2011
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Ingår i: Circulation research. - 1524-4571. ; 109:11, s. 1210-8
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Tidskriftsartikel (refereegranskat)abstract
- The innate immune system and in particular the pattern-recognition receptors Toll-like receptors have recently been linked to atherosclerosis. Consequently, inhibition of various signaling molecules downstream of the Toll-like receptors has been tested as a strategy to prevent progression of atherosclerosis. Receptor-interacting protein 2 (Rip2) is a serine/threonine kinase that is involved in multiple nuclear factor-κB (NFκB) activation pathways, including Toll-like receptors, and is therefore an interesting potential target for pharmaceutical intervention.
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| 5. |
- Nilton, Anna, et al.
(författare)
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Targeting Zfp148 activates p53 and reduces tumor initiation in the gut
- 2016
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Ingår i: OncoTarget. - : Impact Journals, LLC. - 1949-2553. ; 7:35, s. 56183-56192
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor Zinc finger protein 148 (Zfp148, ZBP-89, BFCOL, BERF1, htβ) interacts physically with the tumor suppressor p53, but the significance of this interaction is not known. We recently showed that knockout of Zfp148 in mice leads to ectopic activation of p53 in some tissues and cultured fibroblasts, suggesting that Zfp148 represses p53 activity. Here we hypothesize that targeting Zfp148 would unleash p53 activity and protect against cancer development, and test this idea in the APCMin/+ mouse model of intestinal adenomas. Loss of one copy of Zfp148 markedly reduced tumor numbers and tumor-associated intestinal bleedings, and improved survival. Furthermore, after activation of β-catenin-the initiating event in colorectal cancer-Zfp148 deficiency activated p53 and induced apoptosis in intestinal explants of APCMin/+ mice. The anti-tumor effect of targeting Zfp148 depended on p53, as Zfp148 deficiency did not affect tumor numbers in APCMin/+ mice lacking one or both copies of Trp53. The results suggest that Zfp148 controls the fate of newly transformed intestinal tumor cells by repressing p53 and that targeting Zfp148 might be useful in the treatment of colorectal cancer.
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| 6. |
- Pandita, Ankur, et al.
(författare)
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Intussusceptive angiogenesis in human metastatic malignant melanoma. : Intussusception in human melanoma
- 2021
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Ingår i: The American Journal of Pathology. - : Elsevier BV. - 1525-2191 .- 0002-9440. ; 191:11, s. 2023-2038
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenesis supplies oxygen and nutrients to growing tumors. Inhibiting angiogenesis may stop tumor growth, but vascular endothelial growth factor inhibitors have limited effect in most tumors. The limited effect may be explained by an additional, less vascular endothelial growth factor-driven, form of angiogenesis known as intussusceptive angiogenesis. The importance of intussusceptive angiogenesis in human tumors is not known. Epifluorescence and confocal microscopy was used to visualize intravascular pillars, the hallmark structure of intussusceptive angiogenesis, in tumors. Human malignant melanoma metastases, patient-derived melanoma xenografts in mice (PDX), and genetically engineered BRAF-induced, PTEN-deficient (BPT) mice (BrafCA/+Ptenf/fTyr-Cre+/0-mice) were analyzed for pillars. Gene expression in human melanoma metastases and PDXs was analyzed by RNA sequencing. Matrix metalloproteinase 9 (MMP9) protein expression and T-cell and macrophage infiltration in tumor sections were determined with multiplex immunostaining. Intravascular pillars were detected in human metastases but rarely in PDXs and not in BPT mice. The expression of MMP9 mRNA was higher in human metastases compared with PDXs. High expression of MMP9 protein as well as infiltration of macrophages and T-cell infiltration were detected in proximity to intravascular pillars. MMP inhibition blocked formation of pillars, but not tubes or tip cells, invitro. In conclusion, intussusceptive angiogenesis may contribute to the growth of human melanoma metastases. MMP inhibition blocked pillar formation invitro and should be further investigated as a potential anti-angiogenic drug target in metastatic melanoma.
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| 7. |
- Sjögren, Lovisa, et al.
(författare)
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Postprandial effects of the phosphodiesterase-5 inhibitor tadalafil in people with well-controlled Type 2 diabetes mellitus: a randomized controlled trial.
- 2016
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Ingår i: Diabetic medicine : a journal of the British Diabetic Association. - : Wiley. - 1464-5491. ; 33:9, s. 1299-1301
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Tidskriftsartikel (refereegranskat)abstract
- Type 2 diabetes mellitus is a serious global health problem that is hard to treat in the long term, prompting great efforts to find new drug targets. Little attention has been paid, however, to the metabolic significance of the microcirculation in insulin-sensitive tissues, despite the fact that microvascular insulin resistance and endothelial dysfunction are closely associated and have been shown to precede Type 2 diabetes [1]. Endothelial nitric oxide plays a major role in mediating the beneficial effects of insulin on capillary recruitment and muscle glucose uptake [2] and in suppression of inflammatory pathways, including those activated by a high-fat diet [3]. This article is protected by copyright. All rights reserved.
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| 8. |
- Wilhelmson, Anna S K, et al.
(författare)
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Increased Intimal Hyperplasia After Vascular Injury in Male Androgen Receptor-Deficient Mice
- 2016
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Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 157:10, s. 3915-3923
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Tidskriftsartikel (refereegranskat)abstract
- Intimal hyperplasia is a vascular pathological process involved in the pathogenesis of atherosclerosis. Data suggest that T, the most important sex steroid hormone in males, protects men from atherosclerotic cardiovascular disease. T mainly acts via the androgen receptor (AR), and in this study we evaluated formation of intimal hyperplasia in male AR knockout (ARKO) mice using a vascular injury model. Two weeks after ligation of the carotid artery, male ARKO mice showed increased intimal area and intimal thickness compared with controls. After endothelial denudation by an in vivo scraping injury, there was no difference in the reendothelialization in ARKO compared with control mice. Ex vivo, we observed increased outgrowth of vascular smooth muscle cells from ARKO compared with control aortic tissue explants; the number of outgrown cells was almost doubled in ARKO. In vitro, stimulation of human aortic vascular smooth muscle cells with a physiological T concentration inhibited both migration and proliferation of the cells. Analyzing the expression of central regulators of cell proliferation and migration, we found that mRNA and protein levels of p27 were lower in uninjured arteries from ARKO mice and that T replacement to castrated male mice increased p27 mRNA in an AR-dependent manner. In conclusion, AR deficiency in male mice increases intimal hyperplasia in response to vascular injury, potentially related to the effects of androgens/AR to inhibit proliferation and migration of smooth muscle cells.
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| 9. |
- Yrlid, Ulf, 1971, et al.
(författare)
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Endothelial repair is dependent on CD11c(+) leukocytes to establish regrowing endothelial sheets with high cellular density
- 2019
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Ingår i: Journal of Leukocyte Biology. - : Oxford University Press (OUP). - 0741-5400 .- 1938-3673. ; 105:1, s. 195-202
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial injury makes the vessel wall vulnerable to cardiovascular diseases. Injured endothelium regenerates by collective sheet migration, that is, the endothelial cells coordinate their motion and regrow as a sheet of cells with retained cell-cell contacts into the wounded area. Leukocytes appear to be involved in endothelial repair in vivo; however, little is known about their identity and role in the reparative sheet migration process. To address these questions, we developed a high-quality en face technique that enables visualizing of leukocytes and endothelial cells simultaneously following an endoluminal scratch wound injury of the mouse carotid artery. We discovered that regrowing endothelium forms a broad proliferative front accompanied by CD11c(+) leukocytes. Functionally, the leukocytes were dispensable for the initial migratory response of the regrowing endothelial sheet, but critical for the subsequent formation and maintenance of a front zone with high cellular density. Marker expression analyses, genetic fate mapping, phagocyte targeting experiments, and mouse knock-out experiments indicate that the CD11c(+) leukocytes were mononuclear phagocytes with an origin from both Ly6C(high) and Ly6C(low) monocytes. In conclusion, CD11c(+) mononuclear phagocytes are essential for a proper endothelial regrowth following arterial endoluminal scratch injury. Promoting the endothelial-preserving function of CD11c(+) leukocytes may be a strategy to enhance endothelial repair following surgical and endovascular procedures.
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| 10. |
- Andersson, Linda, 1973, et al.
(författare)
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Deficiency in perilipin 5 reduces mitochondrial function and membrane depolarization in mouse hearts.
- 2017
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Ingår i: The international journal of biochemistry & cell biology. - : Elsevier BV. - 1878-5875 .- 1357-2725. ; 91:Pt A, s. 9-13
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Tidskriftsartikel (refereegranskat)abstract
- Myocardial triglycerides stored in lipid droplets are important in regulating the intracellular delivery of fatty acids for energy generation in mitochondria, for membrane biosynthesis, and as agonists for intracellular signaling. Previously, we showed that deficiency in the lipid droplet protein perilipin 5 (Plin5) markedly reduces triglyceride storage in cardiomyocytes and increases the flux of fatty acids into phospholipids. Here, we investigated whether Plin5 deficiency in cardiomyocytes alters mitochondrial function. We found that Plin5 deficiency reduced mitochondrial oxidative capacity. Furthermore, in mitochondria from Plin5((-/)(-)) hearts, the fatty acyl composition of phospholipids in mitochondrial membranes was altered and mitochondrial membrane depolarization was markedly compromised. These findings suggest that mitochondria isolated from hearts deficient in Plin5, have specific functional defects.
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