| 61. |
- Anders, Emma, et al.
(författare)
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LL-37-induced human osteoblast cytotoxicity and permeability occurs independently of cellular LL-37 uptake through clathrin-mediated endocytosis
- 2018
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X. ; 501:1, s. 280-285
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Tidskriftsartikel (refereegranskat)abstract
- The host defense peptide LL-37 is cytotoxic for bacteria but it has also been reported to reduce host cell viability through an intracellular mechanism. LL-37-evoked cytotoxicity may be involved in the loss of bone tissue in periodontitis which is an inflammatory disease characterized by high concentrations of LL-37 observed locally in the periodontal tissue at the inflammation process. Here, we showed that LL-37 reduced human osteoblast-like MG63 cell viability assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and increased plasma membrane permeability determined by measuring intracellular Ca2+ levels and lactate dehydrogenase (LDH) release. Treatment with chlorpromazine, a well-recognized inhibitor of clathrin-mediated endocytosis, reduced cellular uptake of synthesized LL-37 b y about 30% assessed by Western blotting and ELISA, while filipin, an inhibitor of caveolin-mediated endocytosis, had no effect. The chlorpromazine-induced attenuation of LL-37 uptake was not associated with modulation of LL-37-induced cytotoxicity and LL-37-evoked plasma membrane permeability. Clathrin heavy chain 2 is a major protein of the polyhedral coat of coated pits and vesicles encoded by clathrin heavy chain like 1 gene. Down-regulation of clathrin heavy chain like 1 gene activity by siRNA reduced uptake of LL-37 but did not affect LL-37-induced cytotoxicity and permeability. Thus, we show, using both a pharmacological approach and knockdown of clathrin heavy chain like 1 expression, that LL-37-induced MG63 cell cytotoxicity and permeability occurs independently of LL-37 uptake via clathrin-mediated endocytosis.
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| 62. |
- Bankell, Elisabeth, et al.
(författare)
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Suppression of smooth muscle cell inflammation by myocardin-related transcription factors involves inactivation of TANK-binding kinase 1
- 2024
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Ingår i: Scientific Reports. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Myocardin-related transcription factors (MRTFs: myocardin/MYOCD, MRTF-A/MRTFA, and MRTF-B/MRTFB) suppress production of pro-inflammatory cytokines and chemokines in human smooth muscle cells (SMCs) through sequestration of RelA in the NF-κB complex, but additional mechanisms are likely involved. The cGAS-STING pathway is activated by double-stranded DNA in the cytosolic compartment and acts through TANK-binding kinase 1 (TBK1) to spark inflammation. The present study tested if MRTFs suppress inflammation also by targeting cGAS-STING signaling. Interrogation of a transcriptomic dataset where myocardin was overexpressed using a panel of 56 cGAS-STING cytokines showed the panel to be repressed. Moreover, MYOCD, MRTFA, and SRF associated negatively with the panel in human arteries. RT-qPCR in human bronchial SMCs showed that all MRTFs reduced pro-inflammatory cytokines on the panel. MRTFs diminished phosphorylation of TBK1, while STING phosphorylation was marginally affected. The TBK1 inhibitor amlexanox, but not the STING inhibitor H-151, reduced the anti-inflammatory effect of MRTF-A. Co-immunoprecipitation and proximity ligation assays supported binding between MRTF-A and TBK1 in SMCs. MRTFs thus appear to suppress cellular inflammation in part by acting on the kinase TBK1. This may defend SMCs against pro-inflammatory insults in disease.
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| 63. |
- Bankell, Elisabeth, et al.
(författare)
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The antimicrobial peptide LL-37 triggers release of apoptosis-inducing factor and shows direct effects on mitochondria
- 2022
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Ingår i: Biochemistry and Biophysics Reports. - : Elsevier BV. - 2405-5808. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- The human antimicrobial peptide LL-37 permeabilizes the plasma membrane of host cells, but LL-37-induced direct effects on mitochondrial membrane permeability and function has not been reported. Here, we demonstrate that LL-37 is rapidly (within 20 min) internalized by human osteoblast-like MG63 cells, and that the peptide co-localizes with MitoTracker arguing for accumulation in mitochondria. Subcellular fractionation and Western blot disclose that stimulation with LL-37 (8 μM) for 2 h triggers release of the mitochondrial protein apoptosis-inducing factor (AIF) to the cytosol, whereas LL-37 causes no release of cytochrome C oxidase subunit IV of the inner mitochondrial membrane, suggesting that LL-37 affects mitochondrial membrane permeability in a specific manner. Next, we investigated release of AIF and cytochrome C from isolated mitochondria by measuring immunoreactivity by dot blot. The media of mitochondria treated with LL-37 (8 μM) for 2 h contained 50% more AIF and three times more cytochrome C than that of control mitochondria, showing that LL-37 promotes release of both AIF and cytochrome C. Moreover, in vesicles reflecting mitochondrial membrane lipid composition, LL-37 stimulates membrane permeabilization and release of tracer molecules. We conclude that LL-37 is rapidly internalized by MG63 cells and accumulates in mitochondria, and that the peptide triggers release of pro-apoptotic AIF and directly affects mitochondrial membrane structural properties.
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| 64. |
- Bengnér, Malin, et al.
(författare)
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Independent skewing of the T cell and NK cell compartments associated with cytomegalovirus infection suggests division of labor between innate and adaptive immunity.
- 2014
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Ingår i: Age (Omaha). - : Springer Science and Business Media LLC. - 0161-9152 .- 1574-4647. ; 36:2, s. 571-582
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Tidskriftsartikel (refereegranskat)abstract
- Cytomegalovirus (CMV) infection induces profound changes in different subsets of the cellular immune system. We have previously identified an immune risk profile (IRP) where CMV-associated changes in the T cell compartment, defined as a CD4/CD8 ratio < 1, are associated with increased mortality in elderly people. Since natural killer (NK) cells have an important role in the defense against viral infections, we examined whether the expansion of CD8 + T cells seen in individuals with CD4/CD8 ratio < 1 is coupled to a parallel skewing of the NK cell compartment. A number of 151 subjects were examined with CMV serology and a flow cytometry panel for assessment of T cell and NK cell subsets. CMV-seropositive individuals had higher frequencies of CD57 + and NKG2C + NK cells and lower frequencies of NKG2A + NK cells, in line with a more differentiated NK cell compartment. Intriguingly, however, there was no correlation between CD4/CD8 ratio and NK cell repertoires among CMV-seropositive donors, despite the profound skewing of the T cell compartment in the group with CD4/CD8 ratio < 1. Conversely, donors with profound expansion of NK cells, defined as NKG2C + NK cells with high expression of CD57 and ILT-2, did not display more common changes in their T cell repertoire, suggesting that NK cell expansion is independent of the T cell-defined IRP. Altogether, these results indicate that the effect of CMV on CD8 T cells and NK cells is largely nonoverlapping and independent.
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| 65. |
- Bodahl, Sara, et al.
(författare)
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LL-37 and Double-Stranded RNA Synergistically Upregulate Bronchial Epithelial TLR3 Involving Enhanced Import of Double-Stranded RNA and Downstream TLR3 Signaling
- 2022
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Ingår i: Biomedicines. - : MDPI AG. - 2227-9059. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- The human host defense peptide LL-37 influences double-stranded RNA signaling, but this process is not well understood. Here, we investigate synergistic actions of LL-37 and synthetic double-stranded RNA (poly I:C) on toll-like receptor 3 (TLR3) expression and signaling, and examine underlying mechanisms. In bronchial epithelial BEAS-2B cells, LL-37 potentiated poly I:C-induced TLR3 mRNA and protein expression demonstrated by qPCR and Western blot, respectively. Interestingly, these effects were associated with increased uptake of rhodamine-tagged poly I:C visualized by immunocytochemistry. The LL-37/poly I:C-induced upregulation of TLR3 mRNA expression was prevented by the endosomal acidification inhibitor chloroquine, indicating involvement of downstream TLR3 signaling. The glucocorticoid dexamethasone reduced LL-37/poly I:C-induced TLR3 expression on both mRNA and protein levels, and this effect was associated with increased IκBα protein expression, suggesting that dexamethasone acts via attenuation of NF-κB activity. We conclude that LL-37 potentiates poly I:C-induced upregulation of TLR3 through a mechanism that may involve enhanced import of poly I:C and that LL-37/poly I:C-induced TLR3 expression is associated with downstream TLR3 signaling and sensitive to inhibition of NF-κB activity.
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| 66. |
- Boström, Pontus, 1982, et al.
(författare)
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SNARE proteins mediate fusion between cytosolic lipid droplets and are implicated in insulin sensitivity.
- 2007
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 9:11, s. 1286-93
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Tidskriftsartikel (refereegranskat)abstract
- The accumulation of cytosolic lipid droplets in muscle and liver cells has been linked to the development of insulin resistance and type 2 diabetes. Such droplets are formed as small structures that increase in size through fusion, a process that is dependent on intact microtubules and the motor protein dynein. Approximately 15% of all droplets are involved in fusion processes at a given time. Here, we show that lipid droplets are associated with proteins involved in fusion processes in the cell: NSF (N-ethylmaleimide-sensitive-factor), alpha-SNAP (soluble NSF attachment protein) and the SNAREs (SNAP receptors), SNAP23 (synaptosomal-associated protein of 23 kDa), syntaxin-5 and VAMP4 (vesicle-associated membrane protein 4). Knockdown of the genes for SNAP23, syntaxin-5 or VAMP4, or microinjection of a dominant-negative mutant of alpha-SNAP, decreases the rate of fusion and the size of the lipid droplets. Thus, the SNARE system seems to have an important role in lipid droplet fusion. We also show that oleic acid treatment decreases the insulin sensitivity of heart muscle cells, and this sensitivity is completely restored by transfection with SNAP23. Thus, SNAP23 might be a link between insulin sensitivity and the inflow of fatty acids to the cell.
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| 67. |
- Brodow, Bengt, et al.
(författare)
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Retoriken kring grammatiken : Didaktiska perspektiv på skolgrammatik
- 2000
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Annan publikation (populärvet., debatt m.m.)abstract
- Grammatikundervisningen har en lång tradition inom grundskolans och gymnasiets svenskundervisning, men dess innehåll och uppföljning problematiseras sällan. Tvärtom uppfattas den gärna som självklar och utgör inte sällan ett centralt inslag i svenskämnet. I Grammatiken kring retoriken granskar författarna olika argument som under historien framförts för att legitimera den skolgrammatiska traditionen. I ett kritiskt perspektiv diskuterar de också dagens grammatikundervisning som den kommer till uttryck i olika läromedel samt genom intervjuer med lärare. De argumenterar för en funktionellt inriktad språkundervisning, i vilken språkbeskrivning och metareflektion kan koppas samman med elevers processinriktade skrivande.
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| 68. |
- Brudvik, Jason, et al.
(författare)
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Improvement of energy resolution of ΔE-E CsI/SSD- telescope at measurement of (γ,p)-Reactions using strip information of SSD
- 2016
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Ingår i: Problems of Atomic Science and Technology. - 1682-9344. ; 103:3, s. 111-115
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Tidskriftsartikel (refereegranskat)abstract
- Information on the triggered strips of silicon strip detectors of a MAX-lab ΔE-E CsI/SSD-telescope was used to determination the angular range of emitted reaction particles. It allowed an improvement in the energy resolution of the telescope by decreasing the kinematical broadening of the missing energy spectra of12C(γ,p)11B reaction, and enabling more accurate separation of exited states of residual nucleus.
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| 69. |
- Dahl, Sara, et al.
(författare)
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Human host defense peptide LL-37 facilitates double-stranded RNA pro-inflammatory signaling through up-regulation of TLR3 expression in vascular smooth muscle cells
- 2020
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1420-908X .- 1023-3830. ; 69:6, s. 579-588
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The importance of human host defense peptide LL-37 in vascular innate immunity is not understood. Here, we assess the impact of LL-37 on double-stranded RNA (dsRNA) signaling in human vascular smooth muscle cells.MATERIALS AND METHODS: Cellular import of LL-37 and synthetic dsRNA (poly I:C) were investigated by immunocytochemistry and fluorescence imaging. Transcript and protein expression were determined by qPCR, ELISA and Western blot. Knockdown of TLR3 was performed by siRNA.RESULTS: LL-37 was rapidly internalized, suggesting that it has intracellular actions. Co-stimulation with poly I:C and LL-37 enhanced pro-inflammatory IL-6 and MCP-1 transcripts several fold compared to treatment with poly I:C or LL-37 alone. Poly I:C increased IL-6 and MCP-1 protein production, and this effect was potentiated by LL-37. LL-37-induced stimulation of poly I:C signaling was not associated with enhanced import of poly I:C. Treatment with poly I:C and LL-37 in combination increased expression of dsRNA receptor TLR3 compared to stimulation with poly I:C or LL-37 alone. In TLR3 knockdown cells, treatment with poly I:C and LL-37 in combination had no effect on IL-6 and MCP-1 expression, showing loss of function.CONCLUSIONS: LL-37 potentiates dsRNA-induced cytokine production through up-regulation of TLR3 expression representing a novel pro-inflammatory mechanism.
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| 70. |
- Eich, Torsten, et al.
(författare)
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Positron emission tomography : A real-time tool to quantify early islet engraftment in a preclinical large animal model
- 2007
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Ingår i: Transplantation. - : Ovid Technologies (Wolters Kluwer Health). - 0041-1337 .- 1534-6080. ; 84:7, s. 893-898
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Tidskriftsartikel (refereegranskat)abstract
- Background. Clinical islet transplantation is currently being explored as a therapeutic option for persons with type I diabetes and hypoglycemic unawareness. Techniques to monitor graft survival are urgently needed to optimize the procedure. Therefore, the objective of the present study was to develop a technique for imaging survival of transplanted islets in the peritransplant and early posttransplant phase.Methods. Isolated porcine islets were labeled in vitro with 2-deoxy-2[18F]fluoro-D-glucose ([18F]FDG) and infused intraportally into anesthetized pigs (n=10). Dynamic examination was performed on a positron emission tomography/computed tomography hybrid system.Results. More than 95% of the radioactivity was confined to the islets at the time of transplantation. The peak percentage of infused radioactivity within the liver, quantified at the end of the islet infusion, was only 54±5.1%. The distribution of the radioactivity in the liver was found to be heterogeneous. A whole-body examination showed no accumulation in the lungs or brain; extrahepatic radioactivity was, except urinary excretion, evenly distributed in the pig body.Conclusions. Our results imply that almost 50% of the islets were damaged to the extent that the FDG contained was release within minutes after intraportal transplantation. The distribution of radioactivity without accumulation in the brain indicates that the activity is released from lysed islet cells in the form of [18F]FDG-6P rather than native [18F]FDG. The presented technique shows promise to become a powerful and quantitative tool, readily available in the clinic, to evaluate initial islet engraftment and survival.
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