| 1. |
- Cao, Hao, 1988-, et al.
(författare)
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Multidrug-Resistance like Protein 1 activity in Malpighian tubules regulates lipid homeostasis in Drosophila
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Multidrug-Resistance like Proteins (MRPs) are ubiquitously expressed essential transporters required for many biological processes. Previous studies revealed that MRPs are pivotal for transporting endo- and xenobiotics, conferring resistance to anti-cancer agents and contributing to clearance of oxidative products. Nonetheless, their functions in other biological processes are still unclear. In our investigation, we suppress the expression of Drosophila Multidrug resistance like Protein 1 (MRP) in Malpighian tubules, the functional equivalent to the human kidney, and find this is sufficient to cause abnormal lipid accumulation, as well as disrupt normal feeding patterns. In addition, we suggest that the elevation of lipid contents may be a result of increasing Hr96 (homolog of human Pregnane X receptor) expression, which is known to play a role in detoxification and lipid metabolism processes. Finally, we validate that Malpighian tubules-specific MRP deficiency increases oxidative resistance in fruit flies. In summary, our results demonstrate that inadequate MRP expression in Malpighian tubules can lead to disrupted lipid homeostasis and feeding behavior. However, it may also elevate the oxidative resistance of the flies.
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| 2. |
- Lekholm, Emilia, 1981-
(författare)
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Solute Carriers in Metabolism : Regulation of known and putative solute carriers in the central nervous system
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solute carriers (SLCs) are membrane-bound transporter proteins, important for nutrient, ion, drug and metabolite transport across membranes. A quarter of the human genome codes for membrane-bound proteins, and SLCs make up the largest group of transporter proteins. Due to their ability to transport a large repertoire of substances across, not just the plasma membrane, but also the membrane of internal organelles, they hold a key position in maintaining homeostasis affecting metabolic pathways. Unfortunately, some of the more than 400 identified SLCs are still not fully characterized, even though a quarter of these are associated with human disease. In addition, there are about 30 membrane-bound proteins with strong resemblance to SLCs, of which very little is known. The aim of this thesis is to characterize some of these putative SLCs, focusing on their localization and function in the central nervous system. Since many of the known SLCs play a vital part in metabolism and related pathways, the response to different nutritional conditions has been used as a key method. MFSD14A and MFSD14B, characterized in Paper I, are putative SLCs belonging to the Major Facilitator Superfamily (MFS) and found to be neuronal, differentially expressed in the mouse central nervous system and transiently upregulated in mouse embryonic cortex cultures due to amino acid deprivation. They were also altered in areas of the mouse brain after starvation as well as after high fat diet. In Paper II, the effect on gene regulation due to complete amino acid starvation was monitored in a mouse hypothalamic cell line and 47 different genes belonging to SLCs, or putative SLCs, were found to be affected. Of these, 15 genes belonged to already known amino acid transporters, whereas 32 were putative SLCs with no known function or SLCs not known to react to amino acids. The three SV2 proteins, SV2A, SV2B and SV2C, were studied in Paper III using human neuroblastoma cell lines. The high metabolic state of cancers often result in an upregulation and alteration of transporter proteins, and alterations of the SV2 proteins were found following different treatments performed in this study. Paper IV focused on putative SLCs of MFS type and their role in glucose metabolism. Mouse embryonic cortex cultures were subjected to glucose starvation and the gene expression of 19 putative transporters were analyzed. All but four of the putative transporters were affected either at 3h or 12h of glucose deprivation. In conclusion, several SLCs and putative SLCs studied in this thesis are strongly affected by alteration in metabolism, either due to amino acids or glucose or both. This makes the putative SLCs dynamic membrane-bound proteins, possibly transporters, highly affected by nutritional status and most likely regulated to maintain homeostasis.
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| 3. |
- Linge, Darius, et al.
(författare)
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PLBD : protein-ligand binding database of thermodynamic and kinetic intrinsic parameters
- 2023
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Ingår i: Database. - : OXFORD UNIV PRESS. - 1758-0463. ; 2023
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Tidskriftsartikel (refereegranskat)abstract
- We introduce a protein-ligand binding database (PLBD) that presents thermodynamic and kinetic data of reversible protein interactions with small molecule compounds. The manually curated binding data are linked to protein-ligand crystal structures, enabling structure-thermodynamics correlations to be determined. The database contains over 5500 binding datasets of 556 sulfonamide compound interactions with the 12 catalytically active human carbonic anhydrase isozymes defined by fluorescent thermal shift assay, isothermal titration calorimetry, inhibition of enzymatic activity and surface plasmon resonance. In the PLBD, the intrinsic thermodynamic parameters of interactions are provided, which account for the binding-linked protonation reactions. In addition to the protein-ligand binding affinities, the database provides calorimetrically measured binding enthalpies, providing additional mechanistic understanding. The PLBD can be applied to investigations of protein-ligand recognition and could be integrated into small molecule drug design.
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| 4. |
- Wishart, David S., et al.
(författare)
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HMDB 5.0 : the Human Metabolome Database for 2022
- 2022
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 50:D1, s. D622-D631
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Tidskriftsartikel (refereegranskat)abstract
- The Human Metabolome Database or HMDB (https://hmdb.ca) has been providing comprehensive reference information about human metabolites and their associated biological, physiological and chemical properties since 2007. Over the past 15 years, the HMDB has grown and evolved significantly to meet the needs of the metabolomics community and respond to continuing changes in internet and computing technology. This year's update, HMDB 5.0, brings a number of important improvements and upgrades to the database. These should make the HMDB more useful and more appealing to a larger cross-section of users. In particular, these improvements include: (i) a significant increase in the number of metabolite entries (from 114 100 to 217 920 compounds); (ii) enhancements to the quality and depth of metabolite descriptions; (iii) the addition of new structure, spectral and pathway visualization tools; (iv) the inclusion of many new and much more accurately predicted spectral data sets, including predicted NMR spectra, more accurately predicted MS spectra, predicted retention indices and predicted collision cross section data and (v) enhancements to the HMDB's search functions to facilitate better compound identification. Many other minor improvements and updates to the content, the interface, and general performance of the HMDB website have also been made. Overall, we believe these upgrades and updates should greatly enhance the HMDB's ease of use and its potential applications not only in human metabolomics but also in exposomics, lipidomics, nutritional science, biochemistry and clinical chemistry.
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| 5. |
- Alsiö, Johan, et al.
(författare)
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Exposure to a high-fat high-sugar diet causes strong up-regulation of proopiomelanocortin and differentially affects dopamine D1 and D2 receptor gene expression in the brainstem of rats
- 2014
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 559, s. 18-23
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Tidskriftsartikel (refereegranskat)abstract
- A strong link between obesity and dopamine (DA) has been established by studies associating body weight status to variants of genes related to DA signalling. Human and animal studies investigating this relationship have so far focused mainly on the role of DA within the mesolimbic pathway. The aim of this study was to investigate potential DA receptor dysregulation in the brainstem, where these receptors play a potential role in meal termination, during high-fat high-sugar diet (HFHS) exposure. Expression of other key genes, including proopiomelanocortin (POMC), was also analyzed. We randomized rats into three groups; ad libitum access to HFHS (n=24), restricted HFHS access (n=10), or controls (chow-fed, n=10). After 5 weeks, brainstem gene expression was investigated by qRT-PCR. We observed an increase in POMC expression in ad libitum HFHS-fed rats compared to chow-fed controls (p<0.05). Further, expression of DA D2 receptor mRNA was down-regulated in the brainstem of the HFHS ad libitum-fed rats (p<0.05), whereas expression of the DA D1 receptor was upregulated (p<0.05) in these animals compared to chow-fed rats. In control experiments, we observed no effect relative to chow-fed controls on DA-receptor or POMC gene expression in the hypothalamus of HFHS diet-exposed rats, or in the brainstem of acutely food deprived rats. The present findings suggest brainstem POMC to be responsive to palatable foods, and that DA dysregulation after access to energy-dense diets occurs not only in striatal regions, but also in the brainstem, which could be relevant for overeating and for the development and maintenance of obesity.
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| 6. |
- Benedict, Christian, et al.
(författare)
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Acute sleep deprivation increases serum levels of neuron-specific enolase (NSE) and S100 calcium binding protein B (S-100B) in healthy young men.
- 2014
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Ingår i: Sleep. - : Oxford University Press (OUP). - 1550-9109 .- 0161-8105. ; 37:1, s. 195-8
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Tidskriftsartikel (refereegranskat)abstract
- To investigate whether total sleep deprivation (TSD) affects circulating concentrations of neuron-specific enolase (NSE) and S100 calcium binding protein B (S-100B) in humans. These factors are usually found in the cytoplasm of neurons and glia cells. Increasing concentrations of these factors in blood may be therefore indicative for either neuronal damage, impaired blood brain barrier function, or both. In addition, amyloid β (Aβ) peptides 1-42 and 1-40 were measured in plasma to calculate their ratio. A reduced plasma ratio of Aβ peptides 1-42 to 1-40 is considered an indirect measure of increased deposition of Aβ 1-42 peptide in the brain.
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| 7. |
- Brooks, Samantha J, et al.
(författare)
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BDNF polymorphisms are linked to poorer working memory performance, reduced cerebellar and hippocampal volumes and differences in prefrontal cortex in a Swedish elderly population
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:1, s. e82707-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Brain-derived neurotrophic factor (BDNF) links learning, memory and cognitive decline in elderly, but evidence linking BDNF allele variation, cognition and brain structural differences is lacking.METHODS: 367 elderly Swedish men (n = 181) and women (n = 186) from Prospective Investigation of the Vasculature in Uppsala seniors (PIVUS) were genotyped and the BDNF functional rs6265 SNP was further examined in subjects who completed the Trail Making Task (TMT), verbal fluency task, and had a magnetic resonance imaging (MRI) scan. Voxel-based morphometry (VBM) examined brain structure, cognition and links with BDNF.RESULTS: The functional BDNF SNP (rs6265,) predicted better working memory performance on the TMT with positive association of the Met rs6265, and was linked with greater cerebellar, precuneus, left superior frontal gyrus and bilateral hippocampal volume, and reduced brainstem and bilateral posterior cingulate volumes.CONCLUSIONS: The functional BDNF polymorphism influences brain volume in regions associated with memory and regulation of sensorimotor control, with the Met rs6265 allele potentially being more beneficial to these functions in the elderly.
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| 8. |
- Cedernaes, Jonathan, et al.
(författare)
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Acute sleep loss results in tissue-specific alterations in genome-wide DNA methylation state and metabolic fuel utilization in humans
- 2018
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 4:8
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Tidskriftsartikel (refereegranskat)abstract
- Curtailed sleep promotes weight gain and loss of lean mass in humans, although the underlying molecular mechanisms are poorly understood. We investigated the genomic and physiological impact of acute sleep loss in peripheral tissues by obtaining adipose tissue and skeletal muscle after one night of sleep loss and after one full night of sleep. We find that acute sleep loss alters genome-wide DNA methylation in adipose tissue, and unbiased transcriptome-, protein-, and metabolite-level analyses also reveal highly tissue-specific changes that are partially reflected by altered metabolite levels in blood. We observe transcriptomic signatures of inflammation in both tissues following acute sleep loss, but changes involving the circadian clock are evident only in skeletal muscle, and we uncover molecular signatures suggestive of muscle breakdown that contrast with an anabolic adipose tissue signature. Our findings provide insight into how disruption of sleep and circadian rhythms may promote weight gain and sarcopenia.
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| 9. |
- Fidler, Andrew E., et al.
(författare)
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Sequence polymorphism in a marine bivalve (Perna canaliculus) orphan G protein-coupled receptor gene : preliminary description and possible implications
- 2009
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Ingår i: New Zealand Journal of Marine and Freshwater Research. - 0028-8330 .- 1175-8805. ; 43:4, s. 953-964
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Tidskriftsartikel (refereegranskat)abstract
- G protein-coupled receptors (GPCRs) form a protein superfamily whose members mediate the detection of a diverse range of extracellular signals across a wide taxonomic range. With the exception of opsins, data on molluscan GPCRs are still sparse. Here, we report a preliminary characterisation of a novel GPCR gene, denoted dq646643, from a commercially significant marine bivalve, the green-lipped mussel (Perna canaliculus). Levels of dq646643 transcripts varied widely between different tissues and were detected at their highest levels in the posterior adductor mussel and mantle edge. Phylogenetic analyses were unable to identify any clear dq646643 orthologues, although it was apparent that the dq646643 lineage arose from an early divergence within the metazoan GPCR rhodopsin superfamily. Despite having an ancient lineage, dq646643 displays high levels of translated sequence polymorphism. Although we have no definitive explanation for these high levels of polymorphism, this finding is consistent with reports from other marine invertebrates. These results suggest that, as apparently for oysters, P. canaliculus may carry a significant "genetic load" which needs to be considered during any selective breeding of this species.
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| 10. |
- Fridmanis, Davids, et al.
(författare)
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Formation of new genes explains lower intron density in mammalian Rhodopsin G protein-coupled receptors
- 2007
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 43:3, s. 864-880
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Tidskriftsartikel (refereegranskat)abstract
- Mammalian G protein-coupled receptor (GPCR) genes are characterised by a large proportion of intronless genes or a lower density of introns when compared with GPCRs of invertebrates. It is unclear which mechanisms have influenced intron density in this protein family, which is one of the largest in the mammalian genomes. We used a combination of Hidden Markov Models (HMM) and BLAST searches to establish the comprehensive repertoire of Rhodopsin GPCRs from seven species and performed overall alignments and phylogenetic analysis using the maximum parsimony method for over 1400 receptors in 12 subgroups. We identified 14 different Ancestral Receptor Groups (ARGs) that have members in both vertebrate and invertebrate species. We found that there exists a remarkable difference in the intron density among ancestral and new Rhodopsin GPCRs. The intron density among ARGs members was more than 3.5-fold higher than that within non-ARG members and more than 2-fold higher when considering only the 7TM region. This suggests that the new GPCR genes have been predominantly formed intronless while the ancestral receptors likely accumulated introns during their evolution. Many of the intron positions found in mammalian ARG receptor sequences were found to be present in orthologue invertebrate receptors suggesting that these intron positions are ancient. This analysis also revealed that one intron position is much more frequent than any other position and it is common for a number of phylogenetically different Rhodopsin GPCR groups. This intron position lies within a functionally important, conserved, DRY motif which may form a proto-splice site that could contribute to positional intron insertion. Moreover, we have found that other receptor motifs, similar to DRY, also contain introns between the second and third nucleotide of the arginine codon which also forms a proto-splice site. Our analysis presents compelling evidence that there was not a major loss of introns in mammalian GPCRs and formation of new GPCRs among mammals explains why these have fewer introns compared to invertebrate GPCRs. We also discuss and speculate about the possible role of different RNA- and DNA-based mechanisms of intron insertion and loss.
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