| 1. |
- Franck, Marina Christina Mikaela, et al.
(författare)
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Urocortin3-expressing neurons in sensory transmission
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Urocortin 3 (UCN3) is a neuropeptide involved in mechanosensation and stress regulation, and Ucn3-Cre neurons have been assigned a role in mechanical itch. Here, we show that Ucn3 marks a population of excitatory neurons in the mouse dorsal horn, divided into two non-overlapping subpopulations expressing protein kinase C g or calretinin/calbindin 2. Chemogenetic activation of spinal Ucn3-Cre neurons evoked a targeted biting/licking behavior towards the corresponding dermatome. Genetic deletion of vesicular glutamate transporter 2 (VGLUT2) in Ucn3-Cre neurons removed the phenotype, showing that the biting/licking behavior is VGLUT2-dependent. Conditional deletion of VGLUT2 did not affect acute thermal or mechanical withdrawal responses, nor thermal withdrawal responses after nerve growth factor-induced hypersensitivity or the prurifensive response to 48/80 or von Frey stimuli applied in nape. Instead, we found that a group of spinal Ucn3 neurons were activated in response to artificial scratching or 48/80-induced itch. Electrophysiological experiments showed that spinal Ucn3 neurons received both glycinergic and GABAergic tonic inhibition, and monosynaptic inputs from both Aβ and C fibers, which could be confirmed by rabies tracing. Spinal Ucn3/Ucn3-Cre neurons thus represent a mechanically sensitive population with several roles in the itch-scratch cycle.
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| 2. |
- Aggarwal, Tanya, et al.
(författare)
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Knockdown of SLC38 Transporter Ortholog-CG13743 Reveals a Metabolic Relevance in Drosophila
- 2020
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Ingår i: Frontiers in Physiology. - : FRONTIERS MEDIA SA. - 1664-042X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Solute Carrier (SLC) is a cluster of families of membrane bound transporters, of which many members lack defined substrate profile, and many more are poorly characterized. Many play a vital role in regulating metabolic systems, protein synthesis, and post translational modifications. SLC38 is one of the families of SLCs, which are also known as sodium-coupled neutral amino acid transporters (SNATs). In mice, it has 11 members (SNAT1-11) but in Drosophila there are two homologs for the SLC38 family; CG13743 and CG30394. Here, we show characteristics of Drosophila CG13743 which closely resembles SLC38A11 in humans. SLC38A11 still remains an orphan member of the SLC38 family which has not been functionally well studied. We used the UAS-GAL4 system to investigate and control gene expression using RNAi lines for ubiquitous knockdown of the CG13743 gene. It was found to be expressed mainly in salivary gland and brain. Knockdown flies had reduced body weight and consumed less sugar compared with controls. The gene knockdown also affected stored energy pools (lipids and glycogen) and influenced feeding pattern and total activity. In all, this shows novel findings for the characterization of CG13743 in Drosophila and a possible role in maintaining general metabolic pathways and behavior of the fly.
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| 3. |
- Ceder, Mikaela, 1991-
(författare)
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Characterization of Novel Solute Carriers in Humans, Mice and Flies : Solute Carriers in a Broad and Narrow Perspective
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The solute carrier family is the largest family of membrane-bound transporters in humans, with 430 members divided into 65 subfamilies. They transport various substrates across lipid barriers and are vital for absorption, distribution, metabolism and excretion in all cell types in the body. Despite being involved in vital functions, and their effect on both physiology and pathophysiology, many transporters are not characterized. The aim of this thesis was to study newly identified putative solute carriers of which little is known. In Paper I, the relationship of solute carriers in humans and fruit flies was studied. The study revealed that 54 of the 65 subfamilies in humans have one or more orthologues in fruit flies, and a total of 381 orthologues were identified in fruit flies. In Paper II, a comprehensive study of the putative solute carriers and their response to different sugar concentrations were performed. Several, but not all, putative solute carriers were altered in cell cultures maintained in media containing low or no glucose, and the expression normalized upon refeeding with glucose. Similar results were observed in fruit flies subjected to complete starvation or diets with varying sugar concentrations. Last, in Paper III and IV, characterization of one putative solute carrier, UNC93A, was performed. The studies revealed that UNC93A was a conserved protein with an abundant expression in the body of mice but with a restricted expression in fruit flies. The protein was found to possibly be expressed at, or close to, the plasma membrane of cells and to co-localize with Twik-Acid sensitive potassium channels. UNC93A was found to be important for the renal function in fruit flies and to affect survival and membrane potentials in cells. The findings of this thesis establish a high conservation of several putative solute carriers and that they have a highly dynamic regulation during fluctuating energy and glucose availability. Further, while several clear biological aspects of UNC93A was identified, the exact function of transporter proteins is cumbersome to find and more research about these transporters is needed to fully understand their mechanistic role and their association and/or involvement in health and sickness.
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| 4. |
- Ceder, Mikaela M., et al.
(författare)
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A phylogenetic analysis between humans and D. melanogaster : A repertoire of solute carriers in humans and flies
- 2022
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Ingår i: Gene. - : Elsevier. - 0378-1119 .- 1879-0038. ; 809
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Tidskriftsartikel (refereegranskat)abstract
- The solute carrier (SLC) superfamily is the largest group of transporters in humans, with the role to transport solutes across plasma membranes. The SLCs are currently divided into 65 families with 430 members. Here, we performed a detailed mining of the SLC superfamily and the recent annotated family of “atypical” SLCs in human and D. melanogaster using Hidden Markov Models and PSI-BLAST. Our analyses identified 381 protein sequences in D. melanogaster and of those, 55 proteins have not been previously identified in flies. In total, 11 of the 65 human SLC families were found to not be conserved in flies, while a few families are highly conserved, which perhaps reflects the families’ functions and roles in cellular pathways. This study provides the first collection of all SLC sequences in D. melanogaster and can serve as a SLC database to be used for classification of SLCs in other phyla.
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| 5. |
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| 6. |
- Ceder, Mikaela M., et al.
(författare)
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CG4928 is vital for renal function in fruit flies and membrane potential in cells : A first in-depth characterization of the putative Solute Carrier UNC93A
- 2020
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Ingår i: Frontiers in Cell and Developmental Biology. - : Frontiers Media SA. - 2296-634X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The number of transporter proteins that are not fully characterized is immense. Here, we used Drosophila melanogaster and human cell lines to perform a first in-depth characterization of CG4928, an ortholog to the human UNC93A, of which little is known. Solute carriers regulate and maintain biochemical pathways important for the body, and malfunctioning transport is associated with multiple diseases. Based on phylogenetic analysis, CG4928 is closely related to human UNC93A and has a secondary and a tertiary protein structure and folding similar to major facilitator superfamily transporters. Ubiquitous knockdown of CG4928 causes flies to have a reduced secretion rate from the Malpighian tubules; altering potassium content in the body and in the Malpighian tubules, homologous to the renal system; and results in the development of edema. The edema could be rescued by using amiloride, a common diuretic, and by maintaining the flies on ion-free diets. CG4928-overexpressing cells did not facilitate the transport of sugars and amino acids; however, proximity ligation assay revealed that CG4928 co-localized with TASK(1) channels. Overexpression of CG4928 resulted in induced apoptosis and cytotoxicity, which could be restored when cells were kept in high-sodium media. Furthermore, the basal membrane potential was observed to be disrupted. Taken together, the results indicate that CG4928 is of importance for generating the cellular membrane potential by an unknown manner. However, we speculate that it most likely acts as a regulator or transporter of potassium flows over the membrane.
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| 7. |
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| 8. |
- Ceder, Mikaela M., et al.
(författare)
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Glucose Availability Alters Gene and Protein Expression of Several Newly Classified and Putative Solute Carriers in Mice Cortex Cell Culture and D. melanogaster
- 2020
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Ingår i: Frontiers in Cell and Developmental Biology. - : Frontiers Media SA. - 2296-634X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Many newly identified solute carriers (SLCs) and putative transporters have the possibility to be intricately involved in glucose metabolism. Here we show that many transporters of this type display a high degree of regulation at both mRNA and protein level following no or low glucose availability in mouse cortex cultures. We show that this is also the case in Drosophila melanogaster subjected to starvation or diets with different sugar content. Interestingly, re-introduction of glucose to media, or refeeding flies, normalized the gene expression of a number of the targets, indicating a fast and highly dynamic control. Our findings demonstrate high conservation of these transporters and how dependent both cell cultures and organisms are on gene and protein regulation during metabolic fluctuations. Several transporter genes were regulated simultaneously maybe to initiate alternative metabolic pathways as a response to low glucose levels, both in the cell cultures and in D. melanogaster. Our results display that newly identified SLCs of Major Facilitator Superfamily type, as well as the putative transporters included in our study, are regulated by glucose availability and could be involved in several cellular aspects dependent of glucose and/or its metabolites. Recently, a correlation between dysregulation of glucose in the central nervous system and numerous diseases such as obesity, type 2 diabetes mellitus as well as neurological disease such as Alzheimer’s and Parkinson’s diseases indicate a complex regulation and fine tuning of glucose levels in the brain. The fact that almost one third of transporters and transporter-related proteins remain orphans with unknown or contradictive substrate profile, location and function, pinpoint the need for further research about them to fully understand their mechanistic role and their impact on cellular metabolism.
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| 9. |
- Ceder, Mikaela M., et al.
(författare)
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The Fly Homologue of MFSD11 Is Possibly Linked to Nutrient Homeostasis and Has a Potential Role in Locomotion : A First Characterization of the Atypical Solute Carrier CG18549 in Drosophila Melanogaster
- 2021
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Ingår i: Insects. - : MDPI. - 2075-4450. ; 12:11
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Tidskriftsartikel (refereegranskat)abstract
- Cellular transport and function are dependent on substrate influx and efflux of various compounds. In humans, the largest superfamily of transporters is the SoLute Carriers (SLCs). Many transporters are orphans and little to nothing is known about their expression and/or function, yet they have been assigned to a cluster called atypical SLCs. One of these atypical SLCs is MFSD11. Here we present a first in-depth characterization of the MFSD11, CG18549. By gene expression and behavior analysis on ubiquitous and brain-specific knockdown flies. CG18549 knockdown flies were found to have altered adipokinetic hormone and adipokinteic hormone receptor expression as well as reduced vesicular monoamine transporter expression; to exhibit an altered locomotor behavior, and to have an altered reaction to stress stimuli. Furthermore, the gene expression of CG18549 in the brain was visualized and abundant expression in both the larvae and adult brain was observed, a result that is coherent with the FlyAtlas Anatomy microarray. The exact mechanism behind the observed behaviors is not fully understood, but this study provides new insights into the expression and function of CG18549. Clearly, these results provide a strong example as to why it is vital to fully characterize orphan transporters and through that gain knowledge about the body during normal condition and disease.
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| 10. |
- Ceder, Mikaela M., et al.
(författare)
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The glycine receptor alpha 3 subunit mRNA expression shows sex-dependent differences in the adult mouse brain
- 2023
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Ingår i: BMC Neuroscience. - : Springer Nature. - 1471-2202. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Background The glycinergic system plays an important inhibitory role in the mouse central nervous system, where glycine controls the excitability of spinal itch- and pain-mediating neurons. Impairments of the glycine receptors can cause motor and sensory deficits. Glycine exerts inhibition through interaction with ligand-gated ion channels composed of alpha and beta subunits. We have investigated the mRNA expression of the glycine receptor alpha 3 (Glra3) subunit in the nervous system as well as in several peripheral organs of female and male mice.Results Single-cell RNA sequencing (scRNA-seq) data analysis on the Zeisel et al. (2018) dataset indicated widespread but low expression of Glra3 in vesicular glutamate transporter 2 (Vglut2, Slc17a6) positive and vesicular inhibitory amino acid transporter (Viaat, Slc32a1)positive neurons of the mouse central nervous system. Highest occurrence of Glra3 expression was identified in the cortex, amygdala, and striatal regions, as well as in the hypothalamus, brainstem and spinal cord. Bulk quantitative real-time-PCR (qRT-PCR) analysis demonstrated Glra3 expression in cortex, amygdala, striatum, hypothalamus, thalamus, pituitary gland, hippocampus, cerebellum, brainstem, and spinal cord. Additionally, male mice expressed higher levels of Glra3 in all investigated brain areas compared with female mice. Lastly, RNAscope spatially validated Glra3 expression in the areas indicated by the single-cell and bulk analyses. Moreover, RNAscope analysis confirmed co-localization of Glra3 with Slc17a6 or Slc32a1 in the central nervous system areas suggested from the single-cell data.Conclusions Glra3 expression is low but widespread in the mouse central nervous system. Clear sex-dependent differences have been identified, indicating higher levels of Glra3 in several telencephalic and diencephalic areas, as well as in cerebellum and brainstem, in male mice compared with female mice.
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