| 1. |
- 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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| 2. |
- Tjondro, Harry C., et al.
(författare)
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Hyper-truncated Asn355- And Asn391-glycans modulate the activity of neutrophil granule myeloperoxidase
- 2021
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 296
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Tidskriftsartikel (refereegranskat)abstract
- Myeloperoxidase (MPO) plays essential roles in neutrophil-mediated immunity via the generation of reactive oxidation products. Complex carbohydrates decorate MPO at discrete sites, but their functional relevance remains elusive. To this end, we have characterised the structure–biosynthesis–activity relationship of neutrophil MPO (nMPO). Mass spectrometry demonstrated that nMPO carries both characteristic under-processed and hyper-truncated glycans. Occlusion of the Asn355/Asn391-glycosylation sites and the Asn323-/Asn483-glycans, located in the MPO dimerisation zone, was found to affect the local glycan processing, thereby providing a molecular basis of the site-specific nMPO glycosylation. Native mass spectrometry, mass photometry and glycopeptide profiling revealed significant molecular complexity of diprotomeric nMPO arising from heterogeneous glycosylation, oxidation, chlorination and polypeptide truncation variants and a previously unreported low-abundance monoprotomer. Longitudinal profiling of maturing, mature, granule-separated and pathogen-stimulated neutrophils demonstrated that nMPO is dynamically expressed during granulopoiesis, unevenly distributed across granules and degranulated upon activation. We also show that proMPO-to-MPO maturation occurs during early/mid-stage granulopoiesis. While similar global MPO glycosylation was observed across conditions, the conserved Asn355-/Asn391-sites displayed elevated glycan hyper-truncation, which correlated with higher enzyme activities of MPO in distinct granule populations. Enzymatic trimming of the Asn355-/Asn391-glycans recapitulated the activity gain and showed that nMPO carrying hyper-truncated glycans at these positions exhibits increased thermal stability, polypeptide accessibility and ceruloplasmin-mediated inhibition potential relative to native nMPO. Finally, molecular modelling revealed that hyper-truncated Asn355-glycans positioned in the MPO-ceruloplasmin interface are critical for uninterrupted inhibition. Here, through an innovative and comprehensive approach, we report novel functional roles of MPO glycans, providing new insight into neutrophil-mediated immunity.
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| 3. |
- Lindberg, Frida A., et al.
(författare)
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SLC38A10 knockout mice display a decreased body weight and an increased risk-taking behavior in the open field test
- 2022
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Ingår i: Frontiers in Behavioral Neuroscience. - : Frontiers Media S.A.. - 1662-5153. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- The solute carrier 38 family (SLC38) is a family of 11 members. The most commonsubstrate among these are alanine and glutamine, and members are present in a widerange of tissues with important functions for several biological processes, such as liverand brain function. Some of these transporters are better characterized than others and,in this paper, a behavioral characterization of SLC38A10−/− mice was carried out. Abattery of tests for general activity, emotionality, motor function, and spatial memorywere used. Among these tests, the elevated plus maze, Y-maze, marble burying, andchallenging beamwalk have not been tested on the SLC38A10−/− mice previously, whilethe open field and the rotarod tests have been performed by the International MousePhenotyping Consortium (IMPC). Unlike the results from IMPC, the results from this studyshowed that SLC38A10−/− mice spend less time in the wall zone in the open field testthan WT mice, implying that SLC38A10-deficient mice have an increased explorativebehavior, which suggests an important function of SLC38A10 in brain. The present studyalso confirmed IMPC’s data regarding rotarod performance and weight, showing thatSLC38A10−/− mice do not have an affected motor coordination impairment and havea lower body weight than both SLC38A10+/− and SLC38A10+/+ mice. These resultsimply that a complete deficiency of the SLC38A10 protein might affect body weighthomeostasis, but the underlying mechanisms needs to be studied further.
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| 4. |
- Lindberg, Frida A., et al.
(författare)
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SLC38A10 Deficiency in Mice Affects Plasma Levels of Threonine and Histidine in Males but Not in Females : A Preliminary Characterization Study of SLC38A10(-/-) Mice
- 2023
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Ingår i: Genes. - : MDPI. - 2073-4425. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- Solute carriers belong to the biggest group of transporters in the human genome, but more knowledge is needed to fully understand their function and possible role as therapeutic targets. SLC38A10, a poorly characterized solute carrier, is preliminary characterized here. By using a knockout mouse model, we studied the biological effects of SLC38A10 deficiency in vivo. We performed a transcriptomic analysis of the whole brain and found seven differentially expressed genes in SLC38A10-deficient mice (Gm48159, Nr4a1, Tuba1c, Lrrc56, mt-Tp, Hbb-bt and Snord116/9). By measuring amino acids in plasma, we found lower levels of threonine and histidine in knockout males, whereas no amino acid levels were affected in females, suggesting that SLC38A10(-/-) might affect sexes differently. Using RT-qPCR, we investigated the effect of SLC38A10 deficiency on mRNA expression of other SLC38 members, Mtor and Rps6kb1 in the brain, liver, lung, muscle, and kidney, but no differences were found. Relative telomere length measurement was also taken, as a marker for cellular age, but no differences were found between the genotypes. We conclude that SLC38A10 might be important for keeping amino acid homeostasis in plasma, at least in males, but no major effects were seen on transcriptomic expression or telomere length in the whole brain.
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| 5. |
- 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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| 6. |
- 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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| 7. |
- 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
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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 bedosed below their hyperglycemic threshold to achieve isoform selectivity.
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| 8. |
- Mondal, Tanmoy, 1981, et al.
(författare)
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Sense-antisense lncRNA pair encoded by locus 6p22.3 determines neuroblastoma susceptibility via the USP36-CHD7-SOX9 regulatory axis
- 2018
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Ingår i: Cancer Cell. - : Elsevier BV. - 1535-6108 .- 1878-3686. ; 33:3
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Tidskriftsartikel (refereegranskat)abstract
- Trait-associated loci often map to genomic regions encoding long noncoding RNAs (lncRNAs), but the role of these lncRNAs in disease etiology is largely unexplored. We show that a pair of sense/antisense lncRNA (6p22lncRNAs) encoded by CASC15 and NBAT1 located at the neuroblastoma (NB) risk-associated 6p22.3 locus are tumor suppressors and show reduced expression in high-risk NBs. Loss of functional synergy between 6p22lncRNAs results in an undifferentiated state that is maintained by a gene-regulatory network, including SOX9 located on 17q, a region frequently gained in NB. 6p22lncRNAs regulate SOX9 expression by controlling CHD7 stability via modulating the cellular localization of USP36, encoded by another 17q gene. This regulatory nexus between 6p22.3 and 17q regions may lead to potential NB treatment strategies.
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| 9. |
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| 10. |
- Rube, Tanja, et al.
(författare)
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Development of the Swedish anticholinergic burden scale (Swe-ABS).
- 2023
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Ingår i: BMC geriatrics. - 1471-2318. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Drugs with anticholinergic properties are associated with cognitive adverse effects, especially in patients vulnerable to central muscarinic antagonism. A variety of drugs show weak, moderate or strong anticholinergic effects. Therefore, the cumulative anticholinergic burden should be considered in patients with cognitive impairment. This study aimed to develop a Swedish Anticholinergic Burden Scale (Swe-ABS) to be used in health care and research.A systematic literature review was conducted in PubMed and Ovid Embase to identify previously published tools quantifying anticholinergic drug burden (i.e., exposure). Drugs and grading scores (0-3, no to high anticholinergic activity) were extracted from identified lists. Enteral and parenteral drugs authorized in Sweden were included. Drugs with conflicting scores in the existing lists were assessed by an expert group. Two drugs that were not previously assessed were also added to the evaluation process.The systematic literature search identified the following nine anticholinergic burden scales: Anticholinergic Activity Scale, Anticholinergic Burden Classification, updated Anticholinergic Cognitive Burden scale, Anticholinergic Drug Scale, Anticholinergic Load Scale, Anticholinergic Risk Scale, updated Clinician-rated Anticholinergic Scale, German Anticholinergic Burden Scale and Korean Anticholinergic Burden Scale. A list of drugs with significant anticholinergic effects provided by The Swedish National Board of Health and Welfare was included in the process. The suggested Swe-ABS consists of 104 drugs scored as having weak, moderate or strong anticholinergic effects. Two hundred and fifty-six drugs were listed as having no anticholinergic effects based on evaluation in previous scales. In total, 62 drugs were assessed by the expert group.Swe-ABS is a simplified method to quantify the anticholinergic burden and is easy to use in clinical practice. Publication of this scale might make clinicians more aware of drugs with anticholinergic properties and patients' total anticholinergic burden. Further research is needed to validate the Swe-ABS and evaluate anticholinergic exposure versus clinically significant outcomes.
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