| 1. |
- Abbas, Abdul-Karim, 1959, et al.
(författare)
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Long-term potentiation and insult conditioning in hippocampal slices from young rats: a role for protein synthesis under chemical stress?
- 2010
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Ingår i: The 10th Biennial Meeting of the Asia-Pacific Society for Neurochemistry (APSN), October 17-20, 2010, Phuket, Thailand.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We have previously demonstrated that in young rats (12-20-day-old) a sustained long-term potentiation (LTP) can still be induced under conditions of protein synthesis inhibition. It was therefore suggested that sufficient and necessary proteins were already available at the induction time to accomplish LTP maintenance for several hours. Against this background, we have questioned whether hippocampal slices subjected to certain insult conditions might be more sensitive to protein synthesis inhibitors. High K+ concentration has previously been reported to cause an amnesic effect in vivo as well as increasing protein turnover in vitro. We have here employed a K+ insult model under conditions when protein synthesis was inhibited. Recordings were obtained from hippocampal slices for up to 9 h, with or without a cocktail of protein synthesis inhibitors, containing cycloheximide (60 µM) and anisomycin (25 µM). High potassium (50 mM) was transiently applied (5-15 min) shortly after inducing LTP in one of two separate pathways stimulated alternatively. Additionally, an NMDA-receptor antagonist AP5 was supplied after LTP induction to minimize effects related to depolarization-induced glutamate release. Following elimination of all responses for about 30 min, both test and control responses partly recovered. The degree of remaining LTP, defined as test/control ratio, was reduced in both groups of slices (NMDA-independent depotentiation) but was significantly smaller in the drug-treated ones. We are also running an insult model based on oxidative stress, applying hydrogen peroxide (4-5 mM) before or after LTP induction; however, the results are still insufficient for a final conclusion. The potency of cycloheximide, anisomycin or cocktail of the drugs was verified by measurement of incorporation of [3H]-leucine into trichloracetic acid (TCA) precipitable macromolecules. Cycloheximide, anisomycin or cocktail, at concentrations used here caused 95%, 97% and 95% blocking effect, respectively. Our data confirm the idea that sufficient and necessary constitutive proteins are available in the young hippocampus to maintain LTP under conditions of protein synthesis inhibition. They also reveal that LTP in slices subjected to certain insult conditions early after the induction is sensitive to protein synthesis inhibition, probably due to increase in constitutive proteins turnover.
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| 2. |
- Bauzá-Thorbrügge, Marco, et al.
(författare)
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NRF2 is essential for adaptative browning of white adipocytes.
- 2023
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Ingår i: Redox biology. - : Elsevier. - 2213-2317. ; 68
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Tidskriftsartikel (refereegranskat)abstract
- White adipose tissue browning, defined by accelerated mitochondrial metabolism and biogenesis, is considered a promising mean to treat or prevent obesity-associated metabolic disturbances. We hypothesize that redox stress acutely leads to increased production of reactive oxygen species (ROS), which activate electrophile sensor nuclear factor erythroid 2-Related Factor 2 (NRF2) that over time results in an adaptive adipose tissue browning process. To test this, we have exploited adipocyte-specific NRF2 knockout mice and cultured adipocytes and analyzed time- and dose-dependent effect of NAC and lactate treatment on antioxidant expression and browning-like processes. We found that short-term antioxidant treatment with N-acetylcysteine (NAC) induced reductive stress as evident from increased intracellular NADH levels, increased ROS-production, reduced oxygen consumption rate (OCR), and increased NRF2 levels in white adipocytes. In contrast, and in line with our hypothesis, longer-term NAC treatment led to a NRF2-dependent browning response. Lactate treatment elicited similar effects as NAC, and mechanistically, these NRF2-dependent adipocyte browning responses in vitro were mediated by increased heme oxygenase-1 (HMOX1) activity. Moreover, this NRF2-HMOX1 axis was also important for β3-adrenergic receptor activation-induced adipose tissue browning in vivo. In conclusion, our findings show that administration of exogenous antioxidants can affect biological function not solely through ROS neutralization, but also through reductive stress. We also demonstrate that NRF2 is essential for white adipose tissue browning processes.
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| 3. |
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| 4. |
- Deshpande, J, et al.
(författare)
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Ultrastructural changes in the hippocampal CA1 region following transient cerebral ischemia: evidence against programmed cell death.
- 1992
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Ingår i: Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale. - 0014-4819. ; 88:1, s. 91-105
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Tidskriftsartikel (refereegranskat)abstract
- The ultrastructural changes in the pyramidal neurons of the CA1 region of the hippocampus were studied 6 h, 24 h, 48 h, and 72 h following a transient 10 min period of cerebral ischemia induced by common carotid occlusion combined with hypotension. The pyramidal neurons showed delayed neuronal death (DND), i.e. at 24 h and 48 h postischemia few structural alterations were noted in the light microscope, while at 72 h extensive neuronal degeneration was apparent. The most prominent early ultrastructural changes were polysome disaggregation, and the appearance of electron-dense fluffy dark material associated with tubular saccules. Mitochondria and nuclear elements appeared intact until frank neuronal degeneration. The dark material accumulated with extended periods of recirculation in soma and in the main trunks of proximal dendrites, often beneath the plasma membrane, less frequently in the distal dendrites and seldom in spines. Protein synthesis inhibitors (anisomycin, cycloheximide) and an RNA synthesis inhibitor (actinomycin D), administered by intrahippocampal injections or subcutaneously, did not mitigate neuronal damage. Therefore, DND is probably not apoptosis or a form of programmed cell death. We propose that the dark material accumulating in the postischemic period represents protein complexes, possibly aggregates of proteins or internalized plasma membrane fragments, which may disrupt vital cellular structure and functions, leading to cell death.
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| 5. |
- Izsak, Julia, et al.
(författare)
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Differential acute impact of therapeutically effective and overdose concentrations of lithium on human neuronal single cell and network function
- 2021
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Ingår i: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Lithium salts are used as mood-balancing medication prescribed to patients suffering from neuropsychiatric disorders, such as bipolar disorder and major depressive disorder. Lithium salts cross the blood-brain barrier and reach the brain parenchyma within few hours after oral application, however, how lithium influences directly human neuronal function is unknown. We applied patch–clamp and microelectrode array technology on human induced pluripotent stem cell (iPSC)-derived cortical neurons acutely exposed to therapeutic (<1 mM) and overdose concentrations (>1 mM) of lithium chloride (LiCl) to assess how therapeutically effective and overdose concentrations of LiCl directly influence human neuronal electrophysiological function at the synapse, single-cell, and neuronal network level. We describe that human iPSC-cortical neurons exposed to lithium showed an increased neuronal activity under all tested concentrations. Furthermore, we reveal a lithium-induced, concentration-dependent, transition of regular synchronous neuronal network activity using therapeutically effective concentration (<1 mM LiCl) to epileptiform-like neuronal discharges using overdose concentration (>1 mM LiCl). The overdose concentration lithium-induced epileptiform-like activity was similar to the epileptiform-like activity caused by the GABAA-receptor antagonist. Patch–clamp recordings reveal that lithium reduces action potential threshold at all concentrations, however, only overdose concentration causes increased frequency of spontaneous AMPA-receptor mediated transmission. By applying the AMPA-receptor antagonist and anti-epileptic drug Perampanel, we demonstrate that Perampanel suppresses lithium-induced epileptiform-like activity in human cortical neurons. We provide insights in how therapeutically effective and overdose concentration of lithium directly influences human neuronal function at synapse, a single neuron, and neuronal network levels. Furthermore, we provide evidence that Perampanel suppresses pathological neuronal discharges caused by overdose concentrations of lithium in human neurons.
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| 6. |
- Molinaro, Angela, et al.
(författare)
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Insulin-Driven PI3K-AKT Signaling in the Hepatocyte Is Mediated by Redundant PI3Kα and PI3Kβ Activities and Is Promoted by RAS.
- 2019
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Ingår i: Cell Metabolism. - : Elsevier BV. - 1550-4131 .- 1932-7420. ; 29:6, s. 1400-
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Tidskriftsartikel (refereegranskat)abstract
- Phosphatidylinositol-3-kinase (PI3K) activity is aberrant in tumors, and PI3K inhibitors are investigated as cancer therapeutics. PI3K signaling mediates insulin action in metabolism, but the role of PI3K isoforms in insulin signaling remains unresolved. Defining the role of PI3K isoforms in insulin signaling is necessary for a mechanistic understanding of insulin action and to develop PI3K inhibitors with optimal therapeutic index. We show that insulin-driven PI3K-AKT signaling depends on redundant PI3Kα and PI3Kβ activities, whereas PI3Kδ and PI3Kγ are largely dispensable. We have also found that RAS activity promotes AKT phosphorylation in insulin-stimulated hepatocytes and that promotion of insulin-driven AKT phosphorylation by RAS depends on PI3Kα. These findings reveal the detailed mechanism by which insulin activates AKT, providing an improved mechanistic understanding of insulin signaling. This improved model for insulin signaling predicts that isoform-selective PI3K inhibitors discriminating between PI3Kα and PI3Kβ should be dosed below their hyperglycemic threshold to achieve isoform selectivity.
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| 7. |
- Mottahedin, Amin
(författare)
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Developing brain and systemic inflammation: a "Toll-like" link with consequences
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The developing brain is vulnerable to external insults, and perinatal brain injury (PBI) is a major cause of life-long neurological syndromes such as cerebral palsy. Currently, no pharmaceutical intervention is available. Hypoxia/ischemia (HI), infections and inflammation are implicated in the pathogenesis of PBI. However, the crosstalk between these etiologies is not fully understood. Toll-like receptors (TLR) 3 and TLR2 are responsible for sensing viral and bacterial infections and initiating the inflammatory response. The aim of this thesis was to investigate the effect of systemic inflammation induced by activation of these TLRs on neonatal HI brain injury. We demonstrate that intraperitoneal administration of TLR3 and TLR2 ligands (PolyI:C and P3C, respectively) prior to HI increases the brain injury in neonatal mice. PolyI:C and P3C induced neuroinflammation and altered microglial phenotype as assessed by RT-qPCR, multiplex cytokine assay or flow cytometry. PolyI:C also upregulated the pro-apoptotic gene, Fasl, expression and reduced activation of pro-survival signaling molecule Akt. On the other hand, P3C suppressed mitochondrial respiration, a major mechanism of cellular energy production. P3C, unlike other TLR agonists, induced marked infiltration of leukocytes to the cerebral spinal fluid and brain of neonatal mice and rats. Confocal microscopy, Cre recombinase-mediated gene targeting and in vitro cell transmigra-tion assay revealed the choroid plexus as a site of leukocyte entry. RNA sequencing of the choroid plexus followed by transcriptome cluster analysis and Ingenuity Pathway Analysis revealed potential mechanisms of leukocyte infiltration, including a specific chemotaxis signature and cytoskeleton-related pathways. Finally, we show that N-acetylcysteine treatment inhibits TLR2-mediated leukocyte trafficking in vivo and in vitro. To conclude, this thesis describe a TLR-mediated link between systemic inflammation and developing brain with detrimental consequences on HI brain injury, suggesting potential novel therapeutic strategies.
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| 8. |
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| 9. |
- Turanli, Beste, et al.
(författare)
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Drug Repositioning for Effective Prostate Cancer Treatment
- 2018
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Drug repositioning has gained attention from both academia and pharmaceutical companies as an auxiliary process to conventional drug discovery. Chemotherapeutic agents have notorious adverse effects that drastically reduce the life quality of cancer patients so drug repositioning is a promising strategy to identify non-cancer drugs which have anti-cancer activity as well as tolerable adverse effects for human health. There are various strategies for discovery and validation of repurposed drugs. In this review, 25 repurposed drug candidates are presented as result of different strategies, 15 of which are already under clinical investigation for treatment of prostate cancer (PCa). To date, zoledronic acid is the only repurposed, clinically used, and approved non-cancer drug for PCa. Anti-cancer activities of existing drugs presented in this review cover diverse and also known mechanisms such as inhibition of mTOR and VEGFR2 signaling, inhibition of PI3K/Akt signaling, COX and selective COX-2 inhibition, NF-kappa B inhibition, Wnt/beta - Catenin pathway inhibition, DNMT1 inhibition, and GSK-3 beta inhibition. In addition to monotherapy option, combination therapy with current anti-cancer drugs may also increase drug efficacy and reduce adverse effects. Thus, drug repositioning may become a key approach for drug discovery in terms of time- and cost-efficiency comparing to conventional drug discovery and development process.
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| 10. |
- Hogenkamp, Pleunie S, et al.
(författare)
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Sweet taste perception not altered after acute sleep deprivation in healthy young men.
- 2013
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Ingår i: Somnologie : Schlafforschung und Schlafmedizin = Somnology : sleep research and sleep medicine. - : Springer Science and Business Media LLC. - 1432-9123 .- 1439-054X. ; 17:2, s. 111-114
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Tidskriftsartikel (refereegranskat)abstract
- We hypothesized that acutely sleep-deprived participants would rate ascending concentrations of sucrose as more intense and pleasant, than they would do after one night of normal sleep. Such a finding would offer a potential mechanism through which acute sleep loss could promote overeating in humans.
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