| 1. |
|
|
| 2. |
- Bohman, Hannes, 1965-
(författare)
-
Clozapine protects adult neural stem cells from ketamine-induced cell death in correlation with decreased apoptosis and autophagy.
- 2010
-
Ingår i: Bioscience Reports. - Portland. - 0144-8463 .- 1573-4935. ; 31:40
-
Tidskriftsartikel (refereegranskat)abstract
- Adult neurogenesis, the production of newborn neurons from neural stem cells (NSCs) has been suggested to be decreased in patients with schizophrenia. A similar finding was observed in an animal model of schizophrenia, as indicated by decreased bromodeoxyuridine (BrdU) labelling cells in response to a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist. The antipsychotic drug clozapine was shown to counteract the observed decrease in BrdU-labelled cells in hippocampal dentate gyrus (DG). However, phenotypic determination by immunohistochemistry analysis could not reveal whether BrdU-positive cells were indeed NSCs. Using a previously established cell model for analysing NSC protection in vitro, we investigated a protective effect of clozapine on NSCs. Primary NSCs were isolated from the mouse subventricular zone (SVZ), we show that clozapine had a NSC protective activity alone, as evident by employing an ATP cell viability assay. In contrast, haloperidol did not show any NSC protective properties. Subsequently, cells were exposed to the non-competitive NMDA-receptor antagonist ketamine. Clozapine, but not haloperidol, had a NSC protective/anti-apoptotic activity against ketamine-induced cytotoxicity. The observed NSC protective activity of clozapine was associated with increased expression of the anti-apoptotic marker Bcl-2, decreased expression of the pro-apoptotic cleaved form of caspase-3 and associated with decreased expression of the autophagosome marker 1A/1B-light chain 3 (LC3-II). Collectively, our findings suggest that clozapine may have a protective/anti-apoptotic effect on NSCs, supporting previous in vivo observations, indicating a neurogenesis-promoting activity for clozapine. If the data are further confirmed in vivo, the results may encourage an expanded use of clozapine to restore impaired neurogenesis in schizophrenia.
|
|
| 3. |
- Calderon-González, Karla Gisel, et al.
(författare)
-
Cryptic in vitro ubiquitin ligase activity of HDMX towards p53 is probably regulated by an induced fit mechanism
- 2022
-
Ingår i: Bioscience Reports. - : Portland Press. - 0144-8463 .- 1573-4935. ; 42:7
-
Tidskriftsartikel (refereegranskat)abstract
- HDMX and its homologue HDM2 are two essential proteins for the cell; after genotoxic stress, both are phosphorylated near to their RING domain, specifically at serine 403 and 395, respectively. Once phosphorylated, both can bind the p53 mRNA and enhance its translation; however, both recognize p53 protein and provoke its degradation under normal conditions. HDM2 has been well-recognized as an E3 ubiquitin ligase, whereas it has been reported that even with the high similarity between the RING domains of the two homologs, HDMX does not have the E3 ligase activity. Despite this, HDMX is needed for the proper p53 poly-ubiquitination. Phosphorylation at serine 395 changes the conformation of HDM2, helping to explain the switch in its activity, but no information on HDMX has been published. Here, we study the conformation of HDMX and its phospho-mimetic mutant S403D, investigate its E3 ligase activity and dissect its binding with p53. We show that phospho-mutation does not change the conformation of the protein, but HDMX is indeed an E3 ubiquitin ligase in vitro; however, in vivo, no activity was found. We speculated that HDMX is regulated by induced fit, being able to switch activity accordingly to the specific partner as p53 protein, p53 mRNA or HDM2. Our results aim to contribute to the elucidation of the contribution of the HDMX to p53 regulation.
|
|
| 4. |
- Clayton, Zoe E., et al.
(författare)
-
Induced pluripotent stem cell-derived endothelial cells promote angiogenesis and accelerate wound closure in a murine excisional wound healing mode
- 2018
-
Ingår i: Bioscience Reports. - : PORTLAND PRESS LTD. - 0144-8463 .- 1573-4935. ; 38
-
Tidskriftsartikel (refereegranskat)abstract
- Chronic wounds are a major complication in patients with cardiovascular diseases. Cell therapies have shown potential to stimulate wound healing, but clinical trials using adult stem cells have been tempered by limited numbers of cells and invasive procurement procedures. Induced pluripotent stem cells (iPSCs) have several advantages of other cell types, for example they can be generated in abundance from patients somatic cells (autologous) or those from a matched donor. iPSCs can be efficiently differentiated to functional endothelial cells (iPSC-ECs). Here, we used a murine excisional wound model to test the pro-angiogenic properties of iPSC-ECs in wound healing. Two full-thickness wounds were made on the dorsum of NOD-SCID mice and splinted. iPSC-ECs (5 x 10(5)) were topically applied to one wound, with the other serving as a control. Treatment with iPSC-ECs significantly increased wound perfusion and accelerated wound closure. Expression of endothelial cell (EC) surface marker, platelet endothelial cell adhesion molecule (PECAM-1) (CD31), and pro-angiogenic EC receptor, Tie1, mRNA was up-regulated in iPSC-EC treated wounds at 7 days post-wounding. Histological analysis of wound sections showed increased capillary density in iPSC-EC wounds at days 7 and 14 post-wounding, and increased collagen content at day 14. Anti-GFP fluorescence confirmed presence of iPSC-ECs in the wounds. Bioluminescent imaging (BLI) showed progressive decline of iPSC-ECs over time, suggesting that iPSC-ECs are acting primarily through short-term paracrine effects. These results highlight the pro-regenerative effects of iPSC-ECs and demonstrate that they are a promising potential therapy for intractable wounds.
|
|
| 5. |
- Dekki, N, et al.
(författare)
-
Type 1 diabetic serum interferes with pancreatic beta-cell Ca2+-handling
- 2007
-
Ingår i: Bioscience reports. - : Portland Press Ltd.. - 0144-8463 .- 1573-4935. ; 27:6, s. 321-326
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to clarify the frequency of patients with type 1 diabetes that have serum that increases pancreatic β-cell cytoplasmic free Ca2+ concentration, [Ca2+]i, and if such an effect is also present in serum from first-degree relatives. We also studied a possible link between the serum effect and ethnic background as well as presence of autoantibodies. Sera obtained from three different countries were investigated as follows: 82 Swedish Caucasians with newly diagnosed type 1 diabetes, 56 Americans with different duration of type 1 diabetes, 117 American first-degree relatives of type 1 diabetic patients with a mixed ethnic background and 31 Caucasian Finnish children with newly diagnosed type 1 diabetes. Changes in [Ca2+]i, upon depolarization, were measured in β-cells incubated overnight with sera from type 1 diabetic patients, first-degree relatives or healthy controls. Our data show that there is a group constituting approximately 30% of type 1 diabetic patients of different gender, age, ethnic background and duration of the disease, as well as first-degree relatives of type 1 diabetic patients, that have sera that interfere with pancreatic β-cell Ca2+-handling. This effect on β-cell [Ca2+]i could not be correlated to the presence of autoantibodies. In a defined subgroup of patients with type 1 diabetes and first-degree relatives a defect Ca2+-handling may aggravate development of β-cell destruction.
|
|
| 6. |
|
|
| 7. |
- Hallbeck, Anna-Lotta, et al.
(författare)
-
Interleukin-6 enhances transforming growth factor-alpha mRNA expression in macrophage-like human monocytoid (U-937-1) cells
- 2001
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 21:3, s. 325-339
-
Tidskriftsartikel (refereegranskat)abstract
- We have previously reported that the human monocytoid cell line U-937-1 constitutively expresses transforming growth factor-alpha (TGF-α) and that the steady-state levels of TGF-α mRNA as well as TGF-α protein release increase when U-937-1 cells are differentiated towards monocytes/macrophages. Interleukin-6 (IL-6), which has been shown to have growth-stimulatory effects on a number of cell types, has recently been shown to enhance TGF-α expression in keratinocytes. In the present study we investigated whether TGF-α expression in macrophage-like cells could be regulated by IL-6 using U-937-1 cells as a model system of monocyte/macrophage differentiation. U-937-1 cells were differentiated with retinoic acid (RA), vitamin D3 (Vit-D3) or phorbol-12-myristate-13-acetate (PMA) for 4 days and were then treated with human recombinant IL-6 (1000 IU/ml) for up to 24 hr. Northern blot analysis revealed that cells differentiated with PMA, inducing the phenotype of a secretory macrophage, markedly increased their TGF-α mRNA levels (2.7-fold) when treated with IL-6; the response was maximal at 6 hr and remained high at 12 hr. The expression of the TGF-α gene was accompanied by release of TGF-α protein into the cell culture medium, irrespective of differentiating agent, as demonstrated by enzyme-linked immunosorbent assay (ELISA), as well as by surface expression of pro-TGF-α as determined by indirect immunofluorescent cytometry. However, the superinduction of the TGF-α gene by IL-6 in cells differentiated with PMA was not accompanied by any increase in TGF-α protein release or pro-TGF-α surface expression. We conclude that since IL-6 causes increased steady-state levels of TGF-α mRNA in macrophage-like cells, it may prime these cells for production of this growth factor. Furthermore, we have shown that the IL-6 receptor complex is functional in U-937-1 cells induced to differentiate towards a secretory macrophage by treatment with PMA.
|
|
| 8. |
- Hammarlund, Maria, et al.
(författare)
-
The selectivealpha7 nicotinic acetylcholine receptor agonist AR‑R17779 does not affect ischemia-reperfusion brain injury in mice.
- 2021
-
Ingår i: Bioscience reports. - 1573-4935. ; 41:6
-
Tidskriftsartikel (refereegranskat)abstract
- Inflammation plays a central role in stroke-induced brain injury. The alpha7 nicotinic acetylcholine receptor (α7nAChR) can modulate immune responses in both the periphery and the brain. The aims of this study were to investigate α7nAChR expression in different brain regions and evaluate the potential effect of the selective α7nAChR agonist AR-R17779 on ischemia-reperfusion brain injury in mice. Droplet digital PCR (ddPCR) was used to evaluate the absolute expression of the gene encoding α7nAChR (Chrna7) in hippocampus, striatum, thalamus and cortex in adult, naïve mice. Mice subjected to transient middle cerebral artery occlusion (tMCAO) or sham surgery were treated with α7nAChR agonist AR-R17779 (12 mg/kg) or saline once daily for five days. Infarct size and microglial activation seven days after tMCAO were analyzed using immunohistochemistry. Chrna7 expression was found in all analyzed brain regions in naïve mice, with the highest expression in cortex and hippocampus. At sacrifice, white blood cell count was significantly decreased in AR-R17779 treated mice compared with saline controls in the sham groups, although, no effect was seen in the tMCAO groups. Brain injury and microglial activation was evident seven days after tMCAO. However, no difference was found between mice treated with saline or AR‑R17779. In conclusion, α7nAChR expression varies in different brain regions and, despite a decrease in white blood cells in sham mice receiving AR-R17779, this compound does not affect stroke-induced brain injury.
|
|
| 9. |
|
|
| 10. |
- Hsiao, An-Shan, et al.
(författare)
-
Arabidopsis cytosolic acyl-CoA-binding proteins ACBP4, ACBP5 and ACBP6 have overlapping but distinct roles in seed development
- 2014
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 34:6, s. 865-877
-
Tidskriftsartikel (refereegranskat)abstract
- Eukaryotic cytosolic ACBPs (acyl-CoA-binding proteins) bind acyl-CoA esters and maintain a cytosolic acyl-CoA pool, but the thermodynamics of their protein-lipid interactions and physiological relevance in plants are not well understood. Arabidopsis has three cytosolic ACBPs which have been identified as AtACBP4, AtACBP5 and AtACBP6, and microarray data indicated that all of them are expressed in seeds; AtACBP4 is expressed in early embryogenesis, whereas AtACBP5 is expressed later. ITC (isothermal titration calorimetry) in combination with transgenic Arabidopsis lines were used to investigate the roles of these three ACBPs from Arabidopsis thaliana. The dissociation constants, stoichiometry and enthalpy change of AtACBP interactions with various acyl-CoA esters were determined using ITC. Strong binding of recombinant (r) AtACBP6 with long-chain acyl-CoA (C16-to C18-CoA) esters was observed with dissociation constants in the nanomolar range. However, the affinity of rAtACBP4 and rAtACBP5 to these acyl-CoA esters was much weaker (dissociation constants in the micromolar range), suggesting that they interact with acyl-CoA esters differently from rAtACBP6. When transgenic Arabidopsis expressing AtACBP6pro::GUS was generated, strong GUS (beta-glucuronidase) expression in cotyledonary-staged embryos and seedlings prompted us to measure the acyl-CoA contents of the acbp6 mutant. This mutant accumulated higher levels of C18:1-CoA and C18:1- and C18:2-CoAs in cotyledonary-staged embryos and seedlings, respectively, in comparison with the wild type. The acbp4acbp5acbp6 mutant showed the lightest seed weight and highest sensitivity to abscisic acid during germination, suggesting their physiological functions in seeds.
|
|
| 11. |
- Höddelius, Pia, et al.
(författare)
-
Both Intra- and Extracellular Ca2 Participate in the Regulation of the Lateral Diffusion of the PDGF-β2 Receptor
- 2000
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 20:2, s. 119-127
-
Tidskriftsartikel (refereegranskat)abstract
- When the receptors for platelet-derived growth factor (PDGF) are activatedthey aggregate, become tyrosine-phosphorylated and elicit a cascade ofdown-stream signals, including mobilization of Ca2+ from intra- andextracellular stores. Receptor mobility in the plane of the membrane isa prerequisite for receptor aggregation and further signalling. Using humanforeskin fibroblasts (AG 1523) and fluorescence recovery afterphotobleaching (FRAP), we therefore assessed the lateral mobilitycharacteristics of PDGF-β2 receptors by their diffusioncoefficient (D), and fraction of mobile receptors (R). This was done oncells stimulated with either normal human serum (NHS) or PDGF underdifferent Ca2+-conditions.The results suggest that both intra- and extracellular free Ca2+influence the mobility characteristics of the PDGF-β2receptor. Interestingly, the extracellular Ca2+ seems to imposegeneral restrictions on the mobility of receptors, since R increased whenextracellular Ca2+ was quenched with EGTA, whereas intracellularclamping of Ca2+ transients with MABTAM (BAPT/AM) primarily affectedD. When both intra- and extracellular Ca2+ were quenced, D remainedlow and R high, further supporting the proposition that they achievedistinct effects. Inhibition of tyrosine phosphorylation with Erbstatin,partly inhibited the NHS effects and released PDGF-induced receptorimmobilization. Ratio imaging with Fura-2 displayed that both NHS and PDGFinduced changes in intracellular free [Ca2+]. In view of the presentdata it might have important effects on the state of the receptor in themembrane, for instance by regulating its lateral mobility, communicationwith other receptors and signalling functions in the membrane.
|
|
| 12. |
- Immerstrand, Charlotte, 1974-, et al.
(författare)
-
Height changes associated with pigment aggregation in Xenopus laevis melanophores
- 2004
-
Ingår i: Bioscience Reports. - : Portland Press Ltd.. - 0144-8463 .- 1573-4935. ; 24:3, s. 203-214
-
Tidskriftsartikel (refereegranskat)abstract
- Melanophores are pigment cells found in the skin of lower vertebrates. The brownish-black pigment melanin is stored in organelles called melanosomes. In response to different stimuli, the cells can redistribute the melanosomes, and thereby change colour. During melanosome aggregation, a height increase has been observed in fish and frog melanophores across the cell centre. The mechanism by which the cell increases its height is unknown. Changes in cell shape can alter the electrical properties of the cell, and thereby be detected in impedance measurements. We have in earlier studies of Xenopus laevis melanophores shown that pigment aggregation can be revealed as impedance changes, and therefore we were interested in investigating the height changes associated with pigment aggregation further. Accordingly, we quantified the changes in cell height by performing vertical sectioning with confocal microscopy. In analogy with theories explaining the leading edge of migrating cells, we investigated the possibility that the elevation of plasma membrane is caused by local swelling due to influx of water through HgC12-sensitive aquaporins. We also measured the height of the microtubule structures to assess whether they are involved in the height increase. Our results show that pigment aggregation in X. laevis melanophores resulted in a significant height increase, which was substantially larger when aggregation was induced by latrunculin than with melatonin. Moreover, the elevation of the plasma membrane did not correlate with influx of water through aquaporins or formation of new microtubules, Rather, the accumulation of granules seemed to drive the change in cell height.
|
|
| 13. |
- Johnston, Katharina, et al.
(författare)
-
Mapping the metabolism of five amino acids in bloodstream form Trypanosoma brucei using U- 13C-labelled substrates and LC–MS
- 2019
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 39:5
-
Tidskriftsartikel (refereegranskat)abstract
- The metabolism of the parasite Trypanosoma brucei has been the focus of numerous studies since the 1940s. Recently it was shown, using metabolomics coupled with heavy-atom isotope labelled glucose, that the metabolism of the bloodstream form parasite is more complex than previously thought. The present study also raised a number of questions regarding the origin of several metabolites, for example succinate, only a proportion of which derives from glucose. In order to answer some of these questions and explore the metabolism of bloodstream form T. brucei in more depth we followed the fate of five heavy labelled amino acids – glutamine, proline, methionine, cysteine and arginine – using an LC–MS based metabolomics approach. We found that some of these amino acids have roles beyond those previously thought and we have tentatively identified some unexpected metabolites which need to be confirmed and their function determined.
|
|
| 14. |
- Larsson, Martin, et al.
(författare)
-
Diabetes negatively affects cortical and striatal GABAergic neurons: an effect that is partially counteracted by exendin-4.
- 2016
-
Ingår i: Bioscience reports. - 1573-4935. ; 36:6
-
Tidskriftsartikel (refereegranskat)abstract
- Type 2 diabetic (T2D) patients often develop early cognitive and sensorimotor impairments. The pathophysiological mechanisms behind these problems are largely unknown. Recent studies demonstrate that dysfunctional γ-aminobutyric acid (GABAergic) neurons are involved in age-related cognitive decline. We hypothesized that similar, but earlier dysfunction is taking place under T2D in the neocortex and striatum (two brain areas important for cognition and sensorimotor functions). We also hypothesized that the T2D-induced effects are pharmacologically reversible by anti-diabetic drugs targeting the glucagon-like peptide-1 receptor (GLP-1R). We determined the effect of T2D on cortical and striatal GABAergic neurons positive for glutamic acid decarboxylase-67 (GAD67), calbindin (CB), parvalbumin (PV) and calretinin (CR) by using immunohistochemistry and quantitative microscopy. Young and middle-aged T2D Goto-Kakizaki (GK) (a model of spontaneous T2D) and Wistar rats were used. Furthermore, we determined the therapeutic potential of the GLP1-R agonist exendin-4 (Ex-4) by treating middle-aged GK rats for 6weeks with 0.1μg/kg Ex-4 twice daily. We show that T2D reduced the density of GAD67-positive neurons in the striatum and of CB-positive neurons in both striatum and neocortex. T2D also increased the average volume of PV-positive interneurons in the striatum. Ex-4 treatment increased the density of CB-positive neurons in the striatum of GK rats. Our data demonstrate that T2D negatively affects GAD67 and CB-positive GABAergic neurons in the brain during aging, potentially identifying some of the pathophysiological mechanisms to explain the increased prevalence of neurological complications in T2D. We also show a specific, positive effect of Ex-4 on striatal CB-positive neurons, which could be exploited in therapeutic perspective.
|
|
| 15. |
|
|
| 16. |
- Lirvall, Margareta, et al.
(författare)
-
UVB radiation affects the mobility of epidermal growth factor receptors in human keratinocytes and fibroblasts
- 1996
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 16:3, s. 227-238
-
Tidskriftsartikel (refereegranskat)abstract
- Growth factor receptors transmit biological signals for the stimulation of cell growth in vitro and in vivo and their autocrine stimulation may be involved in tumorigenesis. It is therefore, of great value to understand receptor reactions in response to ultraviolet (UV) light which certain normal human cells are invaribly exposed to during their growth cycle. UV irradiation has recently been shown to deplete antioxidant enzymes in human skin. The aims of the present study were a) to compare the lateral mobility of epidermal growth factor receptors (EGF-R) in cultured human keratinocytes and human foreskin fibroblasts, b) to investigate effects of ultraviolet B radiation on the mobility of EGF-R in these cells, and c) study the response of EGF-R on addition of antioxidant enzymes. The epidermal growth factor receptors were labeled with rhodaminated EGF, the lateral diffusion was determined and the fraction of mobile EGF-R assessed with the fluorescence recovery after photobleaching (FRAP). We found that human keratinocytes display a higher basal level of EGF-R mobility than human skin fibroblasts, viz, with diffusion coefficients (D ± standard error of the mean, SEM) of 4.2 ± 0.2 x 10-10 cm2/s, and 1.8 ± 0.2 x 10-10 cm2/s, respectively. UVB-irradiated fibroblasts showed an almost four-fold increase in the diffusion coefficient; D was 6.3 ± 0.3 x 10-10 cm2/s. The keratinocytes, however, displayed no significant increase in receptor diffusion after irradiation; D was 5.1 ± 0.8 x 10-10 cm2/s. In both cell types the percentage of EGF-R fluorescence recovery after photobleaching, i.e. the fraction of mobile receptors, was significantly increased after irradiation. In keratinocytes it increased from 69% before irradiation to 78% after irradiation. Analogous figures for fibroblasts were 61% and 73%. The effect of UVB on fibroblast receptors was abolished by prior addition of superoxide dismutase (SOD) and catalase (CAT). It is concluded that UVB radiation of fibroblasts and keratinocytes can affect their biophysical properties of EGF-R. The finding that addition of antioxidant enzymes prevented the UVB effect in fibroblasts may indicate the involvement of reactive oxygen metabolites.
|
|
| 17. |
- Ljunggren, Stefan, 1988-, et al.
(författare)
-
Modified lipoproteins in periodontitis : a link to cardiovascular disease?
- 2019
-
Ingår i: Bioscience Reports. - : Portland Press. - 0144-8463 .- 1573-4935. ; 39:3
-
Tidskriftsartikel (refereegranskat)abstract
- There is a strong association between periodontal disease and atherosclerotic cardiovascular disorders. A key event in the development of atherosclerosis is accumulation of modified lipoproteins within the arterial wall. We hypothesize that patients with periodontitis have an altered lipoprotein profile towards an atherogenic form. Therefore, this study aims at identifying modifications of plasma lipoproteins in periodontitis. Lipoproteins from ten female patients with periodontitis and gender- and age-matched healthy controls were isolated by density-gradient-ultracentrifugation. Proteins were separated by two-dimensional gel-electrophoresis and identified by map-matching or by nano-liquid chromatography followed by mass spectrometry. ApoA-I methionine oxidation, Oxyblot, total antioxidant capacity and a multiplex of 71 inflammation-related plasma proteins were assessed.Reduced levels of apoJ, phospholipid transfer protein, apoF, complement C3, paraoxonase 3 and increased levels of alpha-1-antichymotrypsin, apoA-II, apoC-III were found in HDL from the patients. In LDL/VLDL, the levels of apoL-1 and platelet-activating factor acetylhydrolase as well as apo-B fragments were increased. Methionine oxidation of apoA-I was increased in HDL and showed a relationship with periodontal parameters. Alpha-1 antitrypsin and alpha-2-HS glycoprotein were oxidised in LDL/VLDL and antioxidant capacity was increased in the patient group. 17 inflammation-related proteins were important for group separation with the highest discriminating proteins identified as IL-21, Fractalkine, IL-17F, IL-7, IL-1RA and IL-2.Patients with periodontitis have an altered plasma lipoprotein profile, defined by altered protein levels as well as posttranslational and other structural modifications towards an atherogenic form, which supports a role of modified plasma lipoproteins as central in the link between periodontal and cardiovascular disease (CVD).
|
|
| 18. |
- Ljungquist-Höddelius, Pia, et al.
(författare)
-
Lateral diffusion of PDGF β-receptors in human fibroblasts
- 1991
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 11:1, s. 43-52
-
Tidskriftsartikel (refereegranskat)abstract
- When platelet-derived growth factor (PDGF) binds to its receptors a number of biochemical reactions are elicited in the cell. Several models have been presented for the effects of ligand-induced receptor conformation and aggregation on signal transduction but little is known about the direct effects on receptor diffusion. This study concerns the lateral mobility of PDGF receptors in fibroblasts. It was assessed with fluorescence recovery after photobleaching (FRAP), using rhodaminated receptor antibodies or Fab-fragments of the antibody as ligands. The aims of the investigation were: (a) to compare the lateral mobility of membrane receptors of human fibroblasts labelled with either antibodies against the PDGF receptor or Fab-fragments of the same antibodies, and (b) to study the effects of serum of PDGF on the mobility of the receptors. Human foreskin fibroblasts (AG 1523) were grown on coverslips either under standard or under serum-free conditions yielding 'normal' and 'starved' cells, respectively. Two parameters of the diffusion were evaluated; the diffusion coefficient (D) and the mobile fraction (R) of the receptors. We found that normal fibroblasts had a smaller diffusion coefficient and a lower mobile fraction compared to starved cells using antibodies for receptor labelling. The addition of PDGF, just before the measurement, increased the D and R for normal cells, while starved cells, showing higher initial values, displayed slightly reduced values of D and R. After the addition of serum, D increased and R remained low for normal cells, whereas for starved cells both D and R increased to upper limits of 11.0 x 10-10 cm2s-1 and >90% respectively. In general, the D and R values, both in normal and starved cells, were higher for cells labelled with Fab-fragments than for antibody-labelled cells. The results are discussed in relation to the natural complexity of the receptor. and how PDGF, serum, antibodies and Fab-fragments might interfere with receptor structure, aggregation state and membrane diffusion characteristics.
|
|
| 19. |
|
|
| 20. |
- Lundberg, Mathias, et al.
(författare)
-
Clozapine protects adult neural stem cells from ketamine-induced cell death in correlation with decreased apoptosis and autophagy
- 2020
-
Ingår i: Bioscience Reports. - : Portland Press Ltd.. - 0144-8463 .- 1573-4935. ; 40:1
-
Tidskriftsartikel (refereegranskat)abstract
- Adult neurogenesis, the production of newborn neurons from neural stem cells (NSCs) has been suggested to be decreased in patients with schizophrenia. A similar finding was observed in an animal model of schizophrenia, as indicated by decreased bromodeoxyuridine (BrdU) labelling cells in response to a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist. The antipsychotic drug clozapine was shown to counteract the observed decrease in BrdU-labelled cells in hippocampal dentate gyrus (DG). However, phenotypic determination by immunohistochemistry analysis could not reveal whether BrdU-positive cells were indeed NSCs. Using a previously established cell model for analysing NSC protection in vitro, we investigated a protective effect of clozapine on NSCs.Primary NSCs were isolated from the mouse subventricular zone (SVZ), we show that clozapine had a NSC protective activity alone, as evident by employing an ATP cell viability assay. In contrast, haloperidol did not show any NSC protective properties. Subsequently, cells were exposed to the non-competitive NMDA-receptor antagonist ketamine. Clozapine, but not haloperidol, had a NSC protective/anti-apoptotic activity against ketamine-induced cytotoxicity. The observed NSC protective activity of clozapine was associated with increased expression of the anti-apoptotic marker Bcl-2, decreased expression of the pro-apoptotic cleaved form of caspase-3 and associated with decreased expression of the autophagosome marker 1A/1B-light chain 3 (LC3-II).Collectively, our findings suggest that clozapine may have a protective/anti-apoptotic effect on NSCs, supporting previous in vivo observations, indicating a neurogenesis-promoting activity for clozapine. If the data are further confirmed in vivo, the results may encourage an expanded use of clozapine to restore impaired neurogenesis in schizophrenia.
|
|
| 21. |
- Magnusson, Rasmus, 1992-, et al.
(författare)
-
Cross-talks via mTORC2 can explain enhanced activation in response to insulin in diabetic patients
- 2017
-
Ingår i: Bioscience Reports. - : PORTLAND PRESS LTD. - 0144-8463 .- 1573-4935. ; 37
-
Tidskriftsartikel (refereegranskat)abstract
- The molecular mechanisms of insulin resistance in Type 2 diabetes have been extensively studied in primary human adipocytes, and mathematical modelling has clarified the central role of attenuation of mammalian target of rapamycin (mTOR) complex 1 (mTORC1) activity in the diabetic state. Attenuation of mTORC1 in diabetes quells insulin-signalling network-wide, except for the mTOR in complex 2 (mTORC2)-catalysed phosphorylation of protein kinase B (PKB) at Ser(473) (PKB-S473P), which is increased. This unique increase could potentially be explained by feedback and interbranch cross-talk signals. To examine if such mechanisms operate in adipocytes, we herein analysed data from an unbiased phosphoproteomic screen in 3T3-L1 adipocytes. Using a mathematical modelling approach, we showed that a negative signal from mTORC1-p70 S6 kinase (S6K) to rictor-mTORC2 in combination with a positive signal from PKB to SIN1-mTORC2 are compatible with the experimental data. This combined cross-branch signalling predicted an increased PKB-S473P in response to attenuation of mTORC1 - a distinguishing feature of the insulin resistant state in human adipocytes. This aspect of insulin signalling was then verified for our comprehensive model of insulin signalling in human adipocytes. Introduction of the cross-branch signals was compatible with all data for insulin signalling in human adipocytes, and the resulting model can explain all data network-wide, including the increased PKB-S473P in the diabetic state. Our approach was to first identify potential mechanisms in data from a phosphoproteomic screen in a cell line, and then verify such mechanisms in primary human cells, which demonstrates how an unbiased approach can support a direct knowledge-based study.
|
|
| 22. |
- Nalvarte, Ivan, et al.
(författare)
-
The expression and activity of thioredoxin reductase 1 splice variants v1 and v2 regulate the expression of genes associated with differentiation and adhesion
- 2015
-
Ingår i: Bioscience Reports. - : PORTLAND PRESS LTD. - 0144-8463 .- 1573-4935. ; 35:e00269
-
Tidskriftsartikel (refereegranskat)abstract
- The mammalian redox-active selenoprotein thioredoxin reductase (TrxR1) is a main player in redox homoeostasis. It transfers electrons from NADPH to a large variety of substrates, particularly to those containing redox-active cysteines. Previously, we reported that the classical form of cytosolic TrxR1 (TXNRD1_v1), when overexpressed in human embryonic kidney cells (HEK-293), prompted the cells to undergo differentiation [Nalvarte et al. (2004) J. Biol. Chem. 279, 54510-54517]. In the present study, we show that several genes associated with differentiation and adhesion are differentially expressed in HEK-293 cells stably overexpressing TXNRD1_v1 compared with cells expressing its splice variant TXNRD1_v2. Overexpression of these two splice forms resulted in distinctive effects on various aspects of cellular functions including gene regulation patterns, alteration of growth rate, migration and morphology and susceptibility to selenium-induced toxicity. Furthermore, differentiation of the neuroblastoma cell line SH-SY5Y induced by all-trans retinoic acid (ATRA) increased both TXNRD1_v1 and TXNRD1_v2 expressions along with several of the identified genes associated with differentiation and adhesion. Selenium supplementation in the SH-SY5Y cells also induced a differentiated morphology and changed expression of the adhesion protein fibronectin 1 and the differentiation marker cadherin 11, as well as different temporal expression of the studied TXNRD1 variants. These data suggest that both TXNRD1_v1 and TXNRD1_v2 have distinct roles in differentiation, possibly by altering the expression of the genes associated with differentiation, and further emphasize the importance in distinguishing each unique action of different TrxR1 splice forms, especially when studying the gene silencing or knockout of TrxR1.
|
|
| 23. |
- Rydell, Ewa, et al.
(författare)
-
Protein kinase C and casein kinase II activities in two human colon carcinoma cell lines, HT-29 and CaCo-2 : Possible correlation with differentiation
- 1990
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 10, s. 293-299
-
Tidskriftsartikel (refereegranskat)abstract
- Protein kinase C (PK-C) and casein kinase II (CK-II) activities were studied in two human colon carcinoma cell lines (HT-29 and CaCO-2) undergoing differentiationin vitro resulting, in small-intestine-like cells. CaCo-2 cells, when grown under standard conditions, appear to undergo spontaneous differentiation. In these cells PK-C and CK-II activities were determined on day 5, 10 and 15. No significant differences in activities were seen either in PK-C or CK-II activity. HT-29 cells, when grown in glucose-free medium can be stimulated to undergo differentiation which is completed within 20 days. PK-C and CK-II activities were determined after 5, 10, 15, 20 and 25 days, respectively. PK-C activity rose from 7.9±3.5 pmole32P/mg protein/min at day 5 to 37.5±14.8 pmole32P/mg protein/min at day 20. After 25 days the activity was reduced to 20.0±7.8 pmole32P/mg protein/min. CK-II activity did not change significantly during day 5 to 20, but on day 25 there was a significant decrease in CK-II activity from 94.9±6.4 pmole32P/mg protein/min (day 20) to 62.6±3.9 pmole32P/mg protein/min (day 25) p=0.003. The results in this study indicate a role for PK-C and CK-II in cell growth and differentiation.
|
|
| 24. |
- Sjö, Anita, 1944-, et al.
(författare)
-
Distinct Effects of Protein Kinase C on the Barrier Function at Different Developmental Stages
- 2003
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 23:2-3, s. 87-102
-
Tidskriftsartikel (refereegranskat)abstract
- We show here, that activation of protein kinase C by the phorbol ester PMA improves barrier function in colon carcinoma (HT 29) cells. By contrast, in canine kidney (MDCK I) cells it caused increased permeability and opening of tight junctions; the latter has also been noticed in other studies. Thus, with PMA confluent HT 29 cells responded with a reduced passage of 330 kDa sodium fluorescein, increased transepithelial electrical resistance, and a change in the cell shape of the HT 29 cells from an irregular to a regular, hexagonal form. Confocal imaging revealed parallel distinct changes in the staining of occludin and caludin-1, viz. a translocation from cytoplasmic clusters to apical cell–cell contacts. Interestingly, in both cell lines protein kinase A activation caused a decreased in the threonine phosphorylation of occludin that correlated with tight junction assembly in HT 29 cells and tight junction disassembly in MDCK I cells. We conclude that protein kinase C regulation of the epithelial barrier involves specific molecular mechanisms and achieves distinct effects at different developmental stages.
|
|
| 25. |
- Stafford, M. Y. Cynthia, et al.
(författare)
-
Prognostic value of miR-21 for prostate cancer : a systematic review and meta-analysis
- 2022
-
Ingår i: Bioscience Reports. - : PORTLAND PRESS LTD. - 0144-8463 .- 1573-4935. ; 42:1
-
Forskningsöversikt (refereegranskat)abstract
- Elevated levels of miR-21 expression are associated with many cancers, suggesting it may be a promising clinical biomarker. In prostate cancer (PCa), however, there is still no consensus about the usefulness of miR-21 as an indicator of disease progression. This systematic review and meta-analysis was conducted to investigate the value of miR-21 expression as a prognostic measurement in PCa patients. Medline (Ovid), EMBASE, Web of Science, Scopus and Cochrane Library databases were systematically searched for relevant publications between 2010 to 2021. Studies exploring the relationship between miR-21 expression, PCa prognosis and clinicopathological factors were selected for review. Those reporting hazard ratio (HR) and 95% confidence intervals (CIs) were subject to meta-analyses. Fixed-effect models were employed to calculated pooled HRs and 95% CIs. Risk of bias in each study was assessed using QUIPS tool. Certainty of evidence in each meta-analysis was assessed using GRADE guidelines. A total of 64 studies were included in the systematic review. Of these, 11 were eligible for inclusion in meta-analysis. Meta-analyses revealed that high miR-21 expression was associated with poor prognosis: HR = 1.58 (95% CI = 1.19-2.09) for biochemical recurrence, MODERATE certainty; HR = 1.46 (95% CI = 1.06-2.01) for death, VERY LOW certainty; and HR = 1.26 (95% CI = 0.70-2.27) for disease progression, VERY LOW certainty. Qualitative summary revealed elevated miR-21 expression was significantly positively associated with PCa stage, Gleason score and risk groups. This systematic review and meta-analysis suggests that elevated levels of miR-21 are associated with poor prognosis in PCa patients. miR-21 expression may therefore be a useful prognostic biomarker in this disease.
|
|
| 26. |
- Tejle, Katarina, et al.
(författare)
-
Phagocytosis and phagosome maturation are regulated by calcium in J774 macrophages interacting with un-opsonized prey
- 2002
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 22:5-6, s. 529-540
-
Tidskriftsartikel (refereegranskat)abstract
- Phagocytosis by neutrophils, macrophages, and other professional phagocytes requires rapid remodeling of actin. Early phagosomes are surrounded by a rim of F-actin that is disassembled during phagosomoal maturation. Breakdown of periphagosomal F-actin and phagolysosome fusion are calcium dependent processes in neutrophils interacting with serum-opsonized prey, but appears to be calcium independent in macrophages interacting with serum- or IgG-opsonized prey. In the present study, we found that calcium was necessary for phagocytosis, breakdown of periphagosomal F-actin, and phagosomal maturation in J774 macrophages interacting with unopsonized prey. We also observed that lipophosphoglycan (LPG) from Leishmania donovani promastigotes required calcium to exert its inhibitory effect on macrophage phagocytosis and periphagosomal F-actin breakdown. We conclude that calcium is essential for phagocytosis, depolymerization of periphagosomal F-actin, and phagosomal maturation in J774 macrophages interacting with unopsonized prey, as well as for proper functioning of LPG.
|
|
| 27. |
- Ullmann, Eva, et al.
(författare)
-
A novel cytosolic NADH : quinone oxidoreductase from Methanothermobacter marburgensis
- 2014
-
Ingår i: Bioscience Reports. - 0144-8463 .- 1573-4935. ; 34, s. 893-904
-
Tidskriftsartikel (refereegranskat)abstract
- Methanothermobacter marburgensis is a strictly anaerobic, thermophilic methanogenic archaeon that uses methanogenesis to convert H-2 and CO2 to energy. M. marburgensis is one of the best-studied methanogens, and all genes required for methanogenic metabolism have been identified. Nonetheless, the present study describes a gene (Gene ID 9704440) coding for a putative NAD(P)H:quinone oxidoreductase that has not yet been identified as part of the metabolic machinery. The gene product, MmNQO, was successfully expressed, purified and characterized biochemically, as well as structurally. MmNQO was identified as a flavin-dependent NADH: quinone oxidoreductase with the capacity to oxidize NADH in the presence of a wide range of electron acceptors, whereas NADPH was oxidized with only three acceptors. The 1.50 angstrom crystal structure of MmNQO features a homodimeric enzyme where each monomer comprises 196 residues folding into flavodoxin-like alpha/beta domains with non-covalently bound FMN (flavin mononucleotide). The closest structural homologue is the modulator of drug activity B from Streptococcus mutans with 1.6 angstrom root-mean-square deviation on 161 C alpha atoms and 28% amino-acid sequence identity. The low similarity at sequence and structural level suggests that MmNQO is unique among NADH: quinone oxidoreductases characterized to date. Based on preliminary bioreactor experiments, MmNQO could provide a useful tool to prevent overflow metabolism in applications that require cells with high energy demand.
|
|
| 28. |
|
|
| 29. |
|
|
| 30. |
|
|
| 31. |
|
|
| 32. |
- Witt, Carina, et al.
(författare)
-
A finite deformation isogeometric finite element approach to fibre-reinforced composites with fibre bending stiffness
- 2021
-
Ingår i: Journal of Engineering Mathematics. - : Springer Science and Business Media LLC. - 0022-0833 .- 1573-2703. ; 128:1
-
Tidskriftsartikel (refereegranskat)abstract
- It is a common technique in many fields of engineering to reinforce materials with certain types of fibres in order to enhance the mechanical properties of the overall material. Specific simulation methods help to predict the behaviour of these composites in advance. In this regard, a widely established approach is the incorporation of the fibre direction vector as an additional argument of the energy function in order to capture the specific material properties in the fibre direction. While this model represents the transverse isotropy of a material, it cannot capture effects that result from a bending of the fibres and does not include any length scale that might allow the simulation of size effects. In this contribution, an enhanced approach is considered which relies on the introduction of higher-gradient contributions of the deformation map in the stored energy density function and which eventually allows accounting for fibre bending stiffness in simulations. The respective gradient fields are approximated by NURBS basis functions within an isogeometric finite element framework by taking advantage of their characteristic continuity properties. The isogeometric finite element approach that is presented in this contribution for fibre-reinforced composites with fibre bending stiffness accounts for finite deformations. It is shown that the proposed method is in accordance with semi-analytical solutions for a representative boundary value problem. In an additional example it is observed that the initial fibre orientation and the particular bending stiffness of the fibres influence the deformation as well as the stress response of the material.
|
|
| 33. |
- Feng, Tao, et al.
(författare)
-
Adaptive finite element methods for the identification of elastic constants
- 2006
-
Ingår i: Journal of Scientific Computing. - : Springer Science and Business Media LLC. - 0885-7474 .- 1573-7691. ; 26:2, s. 217-235
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, the elastic constants of a material are recovered from measured displacements where the model is the equilibrium equations for the orthotropic case. The finite element method is used for the discretization of the state equation and the Gauss–Newton method is used to solve the nonlinear least squares problem attained from the parameter estimation problem. A posteriori error estimators are derived and used to improve the accuracy by an appropriate mesh refinement. A numerical experiment is presented to show the applicability of the approach.
|
|
