| 1. |
- Babateen, Omar, et al.
(författare)
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Etomidate, propofol and diazepam potentiate GABA-evoked GABAA currents in a cell line derived from Human glioblastoma
- 2015
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 748, s. 101-107
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Tidskriftsartikel (refereegranskat)abstract
- GABAA receptors are pentameric chloride ion channels that are opened by GABA. We have screened a cell line derived from human glioblastoma, U3047MG, for expression of GABAA receptor subunit isoforms and formation of functional ion channels. We identified GABAA receptors subunit α2, α3, α5, β1, β2, β3, δ, γ3, π, and θ mRNAs in the U3047MG cell line. Whole-cell GABA-activated currents were recorded and the half-maximal concentration (EC50) for the GABA-activated current was 36μM. The currents were activated by THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and enhanced by the benzodiazepine diazepam (1μM) and the general anesthetics etomidate and propofol (50μM). In line with the expressed GABAA receptors containing at least the α3β3θ subunits, the receptors were highly sensitive to etomidate (EC50=55nM). Immunocytochemistry identified expression of the α3 and β3 subunit proteins. Our results show that the GABAA receptors in the glial cell line are functional and are modulated by classical GABAA receptor drugs. We propose that the U3047MG cell line may be used as a model system to study GABAA receptors function and pharmacology in glial cells.
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| 2. |
- Babateen, Omar, et al.
(författare)
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Liraglutide modulates GABAergic signaling in rat hippocampal CA3 pyramidal neurons predominantly by presynaptic mechanism
- 2017
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Ingår i: BMC Pharmacology & Toxicology. - : Springer Science and Business Media LLC. - 2050-6511. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Backgroundγ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain where it regulates activity of neuronal networks. The receptor for glucagon-like peptide-1 (GLP-1) is expressed in the hippocampus, which is the center for memory and learning. In this study we examined effects of liraglutide, a GLP-1 analog, on GABA signaling in CA3 hippocampal pyramidal neurons.MethodsWe used patch-clamp electrophysiology to record synaptic and tonic GABA-activated currents in CA3 pyramidal neurons in rat hippocampal brain slices.ResultsWe examined the effects of liraglutide on the neurons at concentrations ranging from one nM to one μM. Significant changes of the spontaneous inhibitory postsynaptic currents (sIPSCs) were only recorded with 100 nM liraglutide and then in just ≈50% of the neurons tested at this concentration. In neurons affected by liraglutide both the sIPSC frequency and the most probable amplitudes increased. When the action potential firing was inhibited by tetrodotoxin (TTX) the frequency and amplitude of IPSCs in TTX and in TTX plus 100 nM liraglutide were similar.ConclusionsThe results demonstrate that liraglutide regulation of GABA signaling of CA3 pyramidal neurons is predominantly presynaptic and more limited than has been observed for GLP-1 and exendin-4 in hippocampal neurons.
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| 3. |
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| 4. |
- Bhandage, Amol, 1988-, et al.
(författare)
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Expression of calcium release-activated and voltage-gated calcium channels genes in peripheral blood mononuclear cells is altered in pregnancy and in type 1 diabetes
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:12
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Tidskriftsartikel (refereegranskat)abstract
- Calcium (Ca2+) is an important ion in physiology and is found both outside and inside cells. The intracellular concentration of Ca2+ is tightly regulated as it is an intracellular signal molecule and can affect a variety of cellular processes. In immune cells Ca2+ has been shown to regulate e.g. gene transcription, cytokine secretion, proliferation and migration. Ca2+ can enter the cytoplasm either from intracellular stores or from outside the cells when Ca2+ permeable ion channels in the plasma membrane open. The Ca2+ release-activated (CRAC) channel is the most prominent Ca2+ ion channel in the plasma membrane. It is formed by ORAI1-3 and the channel is opened by the endoplasmic reticulum Ca2+ sensor proteins stromal interaction molecules (STIM) 1 and 2. Another group of Ca-2(+) channels in the plasma membrane are the voltage-gated Ca2+ (Ca-V) channels. We examined if a change in immunological tolerance is accompanied by altered ORAI, STIM and Ca-V gene expression in peripheral blood mononuclear cells (PBMCs) in pregnant women and in type 1 diabetic individuals. Our results show that in pregnancy and type 1 diabetes ORAI1-3 are up-regulated whereas STIM1 and 2 are down-regulated in pregnancy but only STIM2 in type 1 diabetes. Expression of L-, P/Q-, R- and T-type voltage-gated Ca2+ channels was detected in the PBMCs where the Ca(V)2.3 gene was up-regulated in pregnancy and type 1 diabetes whereas the Ca(V)2.1 and Ca(V)3.2 genes were up-regulated only in pregnancy and the Ca(V)1.3 gene in type 1 diabetes. The results are consistent with that expression of ORAI, STIM and Ca-V genes correlate with a shift in immunological status of the individual in health, as during pregnancy, and in the autoimmune disease type 1 diabetes. Whether the changes are in general protective or in type 1 diabetes include some pathogenic components remains to be clarified.
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| 5. |
- Bhandage, Amol K., 1988-, et al.
(författare)
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AMPA, NMDA and kainate glutamate receptor subunits are expressed in human peripheral blood mononuclear cells (PBMCs) where the expression of GluK4 is altered by pregnancy and GluN2D by depression in pregnant women
- 2017
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Ingår i: Journal of Neuroimmunology. - : Elsevier BV. - 0165-5728 .- 1872-8421. ; 305, s. 51-58
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Tidskriftsartikel (refereegranskat)abstract
- The amino acid glutamate opens cation permeable ion channels, the iGlu receptors. These ion channels are abundantly expressed in the mammalian brain where glutamate is the main excitatory neurotransmitter. The neurotransmitters and their receptors are being increasingly detected in the cells of immune system. Here we examined the expression of the 18 known subunits of the iGlu receptors families; alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate, N-methyl-D-aspartate (NMDA) and delta in human peripheral blood mononuclear cells (PBMCs). We compared the expression of the subunits between four groups: men, non-pregnant women, healthy pregnant women and depressed pregnant women.Out of 18 subunits of the iGlu receptors, mRNAs for 11 subunits were detected in PBMCs from men and nonpregnant women; AMPA: GluA3, GluA4, kainate: GluK2, GluK4, GluK5, NMDA: GluN1, GluN2C, GluN2D, GluN3A, GluN3B, and delta: GluD1. In the healthy and the depressed pregnant women, in addition, the delta GluD2 subunit was identified. The mRNAs for GluK4, GluK5, GluN2C and GluN2D were expressed at a higher level than other subunits. Gender, pregnancy or depression during pregnancy altered the expression of GluA3, GluK4, GluN2D, GluN3B and GluD1 iGlu subunit mRNAs. The greatest changes recorded were the lower GluA3 and GluK4 mRNA levels in pregnant women and the higher GluN2D mRNA level in healthy but not in depressed pregnant women as compared to non-pregnant individuals. Using subunit specific antibodies, the GluK4, GluK5, GluNl, GluN2C and GluN2D subunit proteins were identified in the PBMCs. The results show expression of specific iGlu receptor subunit in the PBMCs and support the idea of physiology-driven changes of iGlu receptors subtypes in the immune cells.
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| 6. |
- Bhandage, Amol K., 1988-, et al.
(författare)
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Depression, GABA, and Age Correlate with Plasma Levels of Inflammatory Markers
- 2019
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 20:24
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Tidskriftsartikel (refereegranskat)abstract
- Immunomodulation is increasingly being recognised as a part of mental diseases. Here, we examined whether levels of immunological protein markers changed with depression, age, or the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). An analysis of plasma samples from patients with a major depressive episode and control blood donors (CBD) revealed the expression of 67 inflammatory markers. Thirteen of these markers displayed augmented levels in patients compared to CBD. Twenty-one markers correlated with the age of the patients, whereas 10 markers correlated with the age of CBD. Interestingly, CST5 and CDCP1 showed the strongest correlation with age in the patients and CBD, respectively. IL-18 was the only marker that correlated with the MADRS-S scores of the patients. Neuronal growth factors (NGFs) were significantly enhanced in plasma from the patients, as was the average plasma GABA concentration. GABA modulated the release of seven cytokines in anti-CD3-stimulated peripheral blood mononuclear cells (PBMCs) from the patients. The study reveals significant changes in the plasma composition of small molecules during depression and identifies potential peripheral biomarkers of the disease.
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| 7. |
- Bhandage, Amol K., 1988-, et al.
(författare)
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GABA Regulates Release of Inflammatory Cytokines From Peripheral Blood Mononuclear Cells and CD4+ T Cells and Is Immunosuppressive in Type 1 Diabetes
- 2018
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Ingår i: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 30, s. 283-294
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Tidskriftsartikel (refereegranskat)abstract
- The neurotransmitter γ-aminobutyric acid (GABA) is an extracellular signaling molecule in the brain and in pancreatic islets. Here, we demonstrate that GABA regulates cytokine secretion from human peripheral blood mononuclear cells (PBMCs) and CD4+ T cells. In anti-CD3 stimulated PBMCs, GABA (100nM) inhibited release of 47 cytokines in cells from patients with type 1 diabetes (T1D), but only 16 cytokines in cells from nondiabetic (ND) individuals. CD4+ T cells from ND individuals were grouped into responder or non-responder T cells according to effects of GABA (100nM, 500nM) on the cell proliferation. In the responder T cells, GABA decreased proliferation, and inhibited secretion of 37 cytokines in a concentration-dependent manner. In the non-responder T cells, GABA modulated release of 8 cytokines. GABA concentrations in plasma from T1D patients and ND individuals were correlated with 10 cytokines where 7 were increased in plasma of T1D patients. GABA inhibited secretion of 5 of these cytokines from both T1D PBMCs and ND responder T cells. The results identify GABA as a potent regulator of both Th1- and Th2-type cytokine secretion from human PBMCs and CD4+ T cells where GABA generally decreases the secretion.
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| 8. |
- Cotman, Andrej Emanuel, et al.
(författare)
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Discovery and Hit-to-Lead Optimization of Benzothiazole Scaffold- Based DNA Gyrase Inhibitors with Potent Activity against Acinetobacter baumannii and Pseudomonas aeruginosa
- 2023
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 66:2, s. 1380-1425
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Tidskriftsartikel (refereegranskat)abstract
- We have developed compounds with a promising activity against Acinetobacter baumannii and Pseudomonas aerugi-nosa, which are both on the WHO priority list of antibiotic -resistant bacteria. Starting from DNA gyrase inhibitor 1, we identified compound 27, featuring a 10-fold improved aqueous solubility, a 10-fold improved inhibition of topoisomerase IV from A. baumannii and P. aeruginosa, a 10-fold decreased inhibition of human topoisomerase II alpha, and no cross-resistance to novobiocin. Cocrystal structures of 1 in complex with Escherichia coli GyrB24 and (S)-27 in complex with A. baumannii GyrB23 and P. aeruginosa GyrB24 revealed their binding to the ATP-binding pocket of the GyrB subunit. In further optimization steps, solubility, plasma free fraction, and other ADME properties of 27 were improved by fine-tuning of lipophilicity. In particular, analogs of 27 with retained anti-Gram-negative activity and improved plasma free fraction were identified. The series was found to be nongenotoxic, nonmutagenic, devoid of mitochondrial toxicity, and possessed no ion channel liabilities.
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| 9. |
- Durcik, Martina, et al.
(författare)
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New Dual Inhibitors of Bacterial Topoisomerases with Broad-Spectrum Antibacterial Activity and In Vivo Efficacy against Vancomycin-Intermediate Staphylococcus aureus
- 2023
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 66:6, s. 3968-3994
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Tidskriftsartikel (refereegranskat)abstract
- A new series of dual low nanomolar benzothiazole inhibitors of bacterial DNA gyrase and topoisomerase IV were developed. The resulting compounds show excellent broad-spectrum antibacterial activities against Gram-positive Enterococcus faecalis, Enterococcus faecium and multidrug resistant (MDR) Staphylococcus aureus strains [best compound minimal inhibitory concentrations (MICs): range, <0.03125–0.25 μg/mL] and against the Gram-negatives Acinetobacter baumannii and Klebsiella pneumoniae (best compound MICs: range, 1–4 μg/mL). Lead compound 7a was identified with favorable solubility and plasma protein binding, good metabolic stability, selectivity for bacterial topoisomerases, and no toxicity issues. The crystal structure of 7a in complex with Pseudomonas aeruginosa GyrB24 revealed its binding mode at the ATP-binding site. Expanded profiling of 7a and 7h showed potent antibacterial activity against over 100 MDR and non-MDR strains of A. baumannii and several other Gram-positive and Gram-negative strains. Ultimately, in vivo efficacy of 7a in a mouse model of vancomycin-intermediate S. aureus thigh infection was also demonstrated.
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| 10. |
- Fellerhoff-Losch, Barbara, et al.
(författare)
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Normal human CD4+ helper T cells express Kv1.1 voltage-gated K+ channels, and selective Kv1.1 block in T cells induces by itself robust TNFα production and secretion and activation of the NFκB non-canonical pathway
- 2016
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Ingår i: Journal of neural transmission. - : Springer Science and Business Media LLC. - 0300-9564 .- 1435-1463. ; 123:3, s. 137-157
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Tidskriftsartikel (refereegranskat)abstract
- TNFα is a very potent and pleiotropic pro-inflammatory cytokine, essential to the immune system for eradicating cancer and microorganisms, and to the nervous system, for brain development and ongoing function. Yet, excess and/or chronic TNFα secretion causes massive tissue damage in autoimmune, inflammatory and neurological diseases and injuries. Therefore, many patients with autoimmune/inflammatory diseases receive anti-TNFα medications. TNFα is secreted primarily by CD4+ T cells, macrophages, monocytes, neutrophils and NK cells, mainly after immune stimulation. Yet, the cause for the pathologically high and chronic TNFα secretion is unknown. Can blocking of a particular ion channel in T cells induce by itself TNFα secretion? Such phenomenon was never revealed or even hypothesized. In this interdisciplinary study we discovered that: (1) normal human T cells express Kv1.1 voltage-gated potassium channel mRNA, and the Kv1.1 membrane-anchored protein channel; (2) Kv1.1 is expressed in most CD4+CD3+ helper T cells (mean CD4+CD3+Kv1.1+ T cells of 7 healthy subjects: 53.09 ± 22.17 %), but not in CD8+CD3+ cytotoxic T cells (mean CD8+CD3+Kv1.1+ T cells: 4.12 ± 3.04 %); (3) electrophysiological whole-cell recordings in normal human T cells revealed Kv currents; (4) Dendrotoxin-K (DTX-K), a highly selective Kv1.1 blocker derived from snake toxin, increases the rate of rise and decay of Kv currents in both resting and activated T cells, without affecting the peak current; (5) DTX-K by itself induces robust TNFα production and secretion by normal human T cells, without elevating IFNγ, IL-4 and IL-10; (6) intact Ca2+ channels are required for DTX-induced TNFα secretion; (7) selective anti-Kv1.1 antibodies also induce by themselves TNFα secretion; (8) DTX-K activates NFκB in normal human T cells via the unique non-canonical-pathway; (9) injection of Kv1.1-blocked human T cells to SCID mice, causes recruitment of resident mouse cells into the liver, alike reported after TNFα injection into the brain. Based on our discoveries we speculate that abnormally blocked Kv1.1 in T cells (and other immune cells?), due to either anti-Kv1.1 autoimmune antibodies, or Kv1.1-blocking toxins alike DTX-K, or Kv1.1-blocking genetic mutations, may be responsible for the chronic/excessive TNFα in autoimmune/inflammatory diseases. Independently, we also hypothesize that selective block of Kv1.1 in CD4+ T cells of patients with cancer or chronic infectious diseases could be therapeutic, since it may: a. augment beneficial secretion and delivery of TNFα to the disease-affected sites; b. induce recruitment and extravasation of curative immune cells and factors; c. improve accessibility of drugs to the brain and few peripheral organs thanks to TNFα-induced increased permeability of organ’s barriers.
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| 11. |
- Flood, Louise, et al.
(författare)
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Interferon-gamma potentiates GABA(A) receptor-mediated inhibitory currents in rat hippocampal CA1 pyramidal neurons
- 2019
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Ingår i: Journal of Neuroimmunology. - : ELSEVIER. - 0165-5728 .- 1872-8421. ; 337
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Tidskriftsartikel (refereegranskat)abstract
- The neural transmission and plasticity can be differentially modulated by various elements of the immune system. Interferon-gamma (IFN-gamma) is a "pro-inflammatory" cytokine mainly produced by T lymphocytes, activates its corresponding receptor and plays important roles under both homeostatic and inflammatory conditions. However, the impact of IFN-gamma on the gamma-aminobutyric acid (GABA)-mediated currents in the hippocampus, a major brain region involved in the cognitive function, has not been investigated. Here we detected abundant expression of both IFN-gamma receptor subunit gene transcripts (Ifngrl and Ifngr2) in the rat hippocampus by quantitative PCR. In addition, we pre-incubated rat hippocampal slices with IFN-gamma (100 ng/ml) and recorded GABA-activated spontaneous and miniature postsynaptic inhibitory currents (sIPSCs and mIPSCs) and tonic currents in hippocampal CAl pyramidal neurons by the whole-cell patch-clamp method. The pre-incubation with IFN-gamma increased the frequency but not the mean amplitude, rise time or decay time of both sIPSCs and mIPSCs in hippocampal CAl pyramidal neurons, suggesting a presynaptic effect of IFN-gamma. Moreover, the GABA-activated tonic currents were enhanced by IFN-gamma. In conclusion, the potentiation of GABAergic currents in hippocampal neurons by IFN-gamma may contribute to the disturbed neuronal excitability and cognitive dysfunction during neuroinflammation.
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| 12. |
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| 13. |
- Hammoud, Hayma, et al.
(författare)
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Insulin differentially modulates GABA signalling in hippocampal neurons and, in an age-dependent manner, normalizes GABA-activated currents in the tg-APPSwe mouse model of Alzheimer's disease
- 2021
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Ingår i: Acta Physiologica. - : John Wiley & Sons. - 1748-1708 .- 1748-1716. ; 232:2
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Tidskriftsartikel (refereegranskat)abstract
- AimWe examined if tonic γ‐aminobutyric acid (GABA)‐activated currents in primary hippocampal neurons were modulated by insulin in wild‐type and tg‐APPSwe mice, an Alzheimer’s disease (AD) model.MethodsGABA‐activated currents were recorded in dentate gyrus (DG) granule cells and CA3 pyramidal neurons in hippocampal brain slices, from 8‐10 weeks old (young) wild‐type mice and in dorsal DG granule cells in adult, 5‐6 and 10‐12 (aged) months old wild‐type and tg‐APPSwe mice, in the absence or presence of insulin, by whole‐cell patch‐clamp electrophysiology.ResultsIn young mice, insulin (1 nM) enhanced the total spontaneous inhibitory postsynaptic current (sIPSCT) density in both dorsal and ventral DG granule cells. The extrasynaptic current density was only increased by insulin in dorsal CA3 pyramidal neurons. In absence of action potentials, insulin enhanced DG granule cells and dorsal CA3 pyramidal neurons miniature IPSCT (mIPSCT) frequency, consistent with insulin regulation of presynaptic GABA release. sIPSCT densities in DG granule cells were similar in wild‐type and tg‐APPSwe mice at 5‐6 months but significantly decreased in aged tg‐APPSwe mice where insulin normalized currents to wild‐type levels. The extrasynaptic current density was increased in tg‐APPSwe mice relative to wild‐type littermates but, only in aged tg‐APPSwe mice did insulin decrease and normalize the current.ConclusionInsulin effects on GABA signalling in hippocampal neurons are selective while multifaceted and context‐based. Not only is the response to insulin related to cell‐type, hippocampal axis‐location, age of animals and disease but also to the subtype of neuronal inhibition involved, synaptic or extrasynaptic GABAA receptors‐activated currents.
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| 14. |
- Jin, Yang, et al.
(författare)
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In a cell-type specific manner, high-affinity GABA-A receptors participate in autocrine and paracrine GABA signaling in human pancreatic islets
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- γ-Aminobutyric acid (GABA), best known as the classical inhibitory neurotransmitter, is also produced and released by pancreatic islet cells. The hormone secreting α, β and δ- cells in human islets express GABA-A receptors that are activated by GABA. GABA signaling in the islets is thought to regulate hormone secretion but how it comes about is unclear. To-date the interstitial GABA concentration and cell-type specific GABA-A receptors have not been characterized. As a consequence, it is not clear how the interstitial GABA in the intact human islet regulates the specific cell-types. We have set- up single-cell RT-PCR combined whole-cell patch-clamp to investigate the functional role of GABA-A receptors in identified cell within intact human islets. GABA-activated tonic current is present in all α, β and δ-cells whereas only the δ-cells respond to GABA with large, transient currents. High-affinity GABA-A receptors activated with interstitial concentrations lower than 10 nM GABA are expressed in both α and β-cells. In the β- cells different subtypes of GABA-A receptors were identified based on single-channel kinetics, current-voltage relation and pharmacology. The data provides insight into the mechanisms underlying GABA regulation of different cell-types in intact human islet.
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| 15. |
- Jin, Yang, et al.
(författare)
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In Intact Islets Interstitial GABA Activates GABA(A) Receptors That Generate Tonic Currents in alpha-Cells
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:6, s. e67228-
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Tidskriftsartikel (refereegranskat)abstract
- In the rat islets γ-aminobutyric acid (GABA) is produced by the β-cells and, at least, the α-cells express the GABAA receptors (GABAA channels). In this study, we examined in intact islets if the interstitial GABA activated the GABAA receptors. We used the patch-clamp technique to record whole-cell and single-channel currents and single-cell RT-PCR to identify the cell-type we recorded from, in the intact rat islets. We further identified which GABAA receptor subunits were expressed. We determined the cell-type of 43 cells we recorded from and of these 49%, 28% and 7% were α, β and δ-cells, respectively. In the remaining 16% of the cells, mRNA transcripts of more than one hormone gene were detected. The results show that in rat islets interstitial GABA activates tonic current in the α-cells but not in the β-cells. Seventeen different GABAA receptor subunits are expressed with high expression of α1, α2, α4, α6, β3, γ1, δ, ρ1, ρ2 and ρ3 subunits whereas no expression was detected for α5 or ε subunits. The abundance of the GABAA receptor subunits detected suggests that a number of GABAA receptor subtypes are formed in the islets. The single-channel and tonic currents were enhanced by pentobarbital and inhibited by the GABAA receptor antagonist SR-95531. The single-channel conductance ranged from 24 to 105 pS. Whether the single-channel conductance is related to subtypes of the GABAA receptor or variable interstitial GABA concentrations remains to be determined. Our results reveal that GABA is an extracellular signaling molecule in rat pancreatic islets and reaches concentration levels that activate GABAA receptors on the glucagon-releasing α-cells.
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| 16. |
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| 17. |
- Jin, Zhe, et al.
(författare)
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GABA-mediated inhibition of human CD4+ T cell functions is enhanced by insulin but impaired by high glucose levels.
- 2024
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Ingår i: EBioMedicine. - 2352-3964. ; 105, s. 105217-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: γ-aminobutyric acid (GABA), known as the main inhibitory neurotransmitter in the brain, exerts immunomodulatory functions by interaction with immune cells, including T cells. Metabolic programs of T cells are closely linked to their effector functions including proliferation, differentiation, and cytokine production. The physiological molecules glucose and insulin may provide environmental cues and guidance, but whether they coordinate to regulate GABA-mediated T cell immunomodulation is still being examined.METHODS: CD4+ T cells that were isolated from blood samples from healthy individuals and from patients with type 1 diabetes (T1D) were activated in vitro. We carried out metabolic assays, multiple proximity extension assay (PEA), ELISA, qPCR, immunoblotting, immunofluorescence staining, flow cytometry analysis, MS-based proteomics, as well as electrophysiology and live-cell Ca2+ imaging.FINDINGS: We demonstrate that GABA-mediated reduction of metabolic activity and the release of inflammatory proteins, including IFNγ and IL-10, were abolished in human CD4+ T cells from healthy individuals and patients with T1D when the glucose concentration was elevated above levels typically observed in healthy people. Insulin increased GABAA receptor-subunit ρ2 expression, enhanced the GABAA receptors-mediated currents and Ca2+ influx. GABA decreased, whereas insulin sustained, hexokinase activity and glycolysis in a glucose concentration-dependent manner.INTERPRETATION: These findings support that metabolic factors, such as glucose and insulin, influence the GABA-mediated immunomodulation of human primary T cells effector functions.FUNDING: The Swedish Children's Diabetes Foundation, The Swedish Diabetes Foundation, The Swedish Research Council 2018-02952, EXODIAB, The Ernfors Foundation, The Thurings Foundation and the Science for Life Laboratory.
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| 18. |
- Jin, Zhe, et al.
(författare)
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GABA signalling in human pancreatic islets
- 2023
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Ingår i: Frontiers in Endocrinology. - : Frontiers Media S.A.. - 1664-2392. ; 14
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Forskningsöversikt (refereegranskat)abstract
- The pancreatic islets are essential microorgans controlling the glucose level in the blood. The islets consist of different cell types which communicate with each other by means of auto- and paracrine interactions. One of the communication molecules produced by and released within the islets is γ-aminobutyric acid (GABA), a well-known inhibitor of neuronal excitability in the mammalian nervous system. Interestingly, GABA is also present in the blood in the nanomolar concentration range. Thus, GABA can affect not only islet function per se (e.g. hormone secretion) but also interactions between immune cells and the pancreatic islet cells in physiological conditions and in pathological states (particularly in type 1 diabetes). In the last decade the interest in GABA signalling in islets has increased. The broad research scope ranges from fundamental physiological studies at the molecular and cellular level to pathological implications and clinical trials. The aim of this mini-review is to outline the current status of the islet GABA field mostly in relation to human islets, to identify the gaps in the current knowledge and what clinical implications GABA signalling may have in islets.
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| 19. |
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| 20. |
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| 21. |
- Korol, Sergiy, et al.
(författare)
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GABA(A) Receptor-Mediated Currents and Hormone mRNAs in Cells Expressing More Than One Hormone Transcript in Intact Human Pancreatic Islets
- 2020
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 21:2
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Tidskriftsartikel (refereegranskat)abstract
- In pancreatic islets, the major cell-types are alpha, beta and delta cells. The gamma-aminobutyric acid (GABA) signalling system is expressed in human pancreatic islets. In single hormone transcript-expressing cells, we have previously characterized the functional properties of islet GABA(A) receptors (iGABA(A)Rs). Here, we extended these studies to islet cells expressing mRNAs for more than one hormone and sought for correlation between iGABA(A)R activity level and relative mRNA expression ratio. The single-cell RT-PCR in combination with the patch-clamp current recordings was used to examine functional properties of iGABA(A)Rs in the multiple hormone mRNA-expressing cells. We detected cells expressing double (alpha/beta, alpha/delta, beta/delta cell-types) and triple (alpha/beta/delta cell-type) hormone transcripts. The most common mixed-identity cell-type was the alpha/beta group where the cells could be grouped into beta- and alpha-like subgroups. The beta-like cells had low GCG/INS expression ratio (<0.6) and significantly higher frequency of iGABA(A)R single-channel openings than the alpha-like cells where the GCG/INS expression ratio was high (>1.2). The hormone expression levels and iGABA(A)R single-channel characteristics varied in the alpha/beta/delta cell-type. Clearly, multiple hormone transcripts can be expressed in islet cells whereas iGABA(A)R single-channel functional properties appear to be alpha or beta cell specific.
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| 22. |
- Korol, Sergiy V, et al.
(författare)
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Functional Characterization of Native, High-Affinity GABAA Receptors in Human Pancreatic β Cells
- 2018
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Ingår i: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- In human pancreatic islets, the neurotransmitter γ-aminobutyric acid (GABA) is an extracellular signaling molecule synthesized by and released from the insulin-secreting β cells. The effective, physiological GABA concentration range within human islets is unknown. Here we use native GABAA receptors in human islet β cells as biological sensors and reveal that 100-1000nM GABA elicit the maximal opening frequency of the single-channels. In saturating GABA, the channels desensitized and stopped working. GABA modulated insulin exocytosis and glucose-stimulated insulin secretion. GABAA receptor currents were enhanced by the benzodiazepine diazepam, the anesthetic propofol and the incretin glucagon-like peptide-1 (GLP-1) but not affected by the hypnotic zolpidem. In type 2 diabetes (T2D) islets, single-channel analysis revealed higher GABA affinity of the receptors. The findings reveal unique GABAA receptors signaling in human islets β cells that is GABA concentration-dependent, differentially regulated by drugs, modulates insulin secretion and is altered in T2D.
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| 23. |
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| 24. |
- Korol, Sergiy V., et al.
(författare)
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GLP-1 and Exendin-4 Transiently Enhance GABA(A) Receptor-Mediated Synaptic and Tonic Currents in Rat Hippocampal CA3 Pyramidal Neurons
- 2015
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 64:1, s. 79-89
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Tidskriftsartikel (refereegranskat)abstract
- GLP-1 is a hormone that stimulates insulin secretion. Receptors for GLP-1 are also found in the brain, including the hippocampus, the centre for memory and learning. Diabetes mellitus is a risk factor for decreased memory functions. We studied effects of GLP-1 and exendin-4, a GLP-1 receptor agonist, on γ-aminobutyric acid (GABA) signaling in hippocampal CA3 pyramidal neurons. GABA is the main inhibitory neurotransmitter and decreases neuronal excitability. GLP-1 (0.01 – 1 nmol/L) transiently enhanced synaptic and tonic currents and the effects were blocked by exendin(9–39). Ten pmol/L GLP-1 increased both the spontaneous inhibitory postsynaptic current (sIPSC) amplitudes and frequency by a factor of 1.8. In 0.1, 1 nmol/L GLP-1 or 10, 50 or 100 nmol/L exendin-4, only the sIPSC frequency increased. The tonic current was enhanced by 0.01 – 1 nmol/L GLP-1 and by 0.5 – 100 nmol/L exendin-4. When action potentials were inhibited by tetrodotoxin (TTX), IPSCs decreased and currents were no longer potentiated by GLP-1 or exendin-4. In contrast, although the tonic current decreased in TTX, it was still enhanced by GLP-1 or exendin-4. The results demonstrate GLP-1 receptor regulation of hippocampal function and are consistent with GLP-1 receptor agonists enhancing GABAA signaling by pre- and postsynaptic mechanisms.
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| 25. |
- Korol, Sergiy V., et al.
(författare)
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Insulin enhances GABAA receptor-mediated inhibitory currents in rat central amygdala neurons
- 2018
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 671, s. 76-81
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Tidskriftsartikel (refereegranskat)abstract
- Insulin, a pancreatic hormone, can access the central nervous system, activate insulin receptors distributed in selective brain regions and affect various cellular functions such as neurotransmission. We have previously shown that physiologically relevant concentration of insulin potentiates the GABAA receptor-mediated tonic inhibition and reduces excitability of rat hippocampal CA1 neurons. The central nucleus of the amygdala (CeA) comprises heterogeneous neuronal populations that can respond to hormonal stimulus. Using quantitative PCR and immunofluorescent labeling, we report that the mRNA and protein of the insulin receptor are abundantly expressed in the rat CeA. The insulin receptor mRNA is also detected in the CeA from post-mortem human brain samples. Furthermore, our whole-cell patch-clamp recordings show that the application of insulin (5 and 50 nM) selectively enhances the frequency and amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs) in rat CeA neurons. Our findings reveal that GABAergic synaptic transmission is a target in the CeA for insulin receptor signaling that may underlie insulin modulation of emotion- and feeding-related behaviors.
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| 26. |
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| 27. |
- Korol, Sergiy V., et al.
(författare)
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The GLP-1 Receptor Agonist Exendin-4 and Diazepam Differentially Regulate GABAA Receptor-Mediated Tonic Currents in Rat Hippocampal CA3 Pyramidal Neurons
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Glucagon-like peptide-1 (GLP-1) is a metabolic hormone that is secreted in a glucose-dependent manner and enhances insulin secretion. GLP-1 receptors are also found in the brain where their signalling affects neuronal activity. We have previously shown that the GLP-1 receptor agonists, GLP-1 and exendin-4 enhanced GABA-activated synaptic and tonic currents in rat hippocampal CA3 pyramidal neurons. The hippocampus is the centre for memory and learning and is important for cognition. Here we examined if exendin-4 similarly enhanced the GABA-activated currents in the presence of the benzodiazepine diazepam. In whole-cell recordings in rat brain slices, diazepam (1 μM), an allosteric positive modulator of GABAA receptors, alone enhanced the spontaneous inhibitory postsynaptic current (sIPSC) amplitude and frequency by a factor of 1.3 and 1.6, respectively, and doubled the tonic GABAA current normally recorded in the CA3 pyramidal cells. Importantly, in the presence of exendin-4 (10 nM) plus diazepam (1 μM), only the tonic but not the sIPSC currents transiently increased as compared to currents recorded in the presence of diazepam alone. The results suggest that exendin-4 potentiates a subpopulation of extrasynaptic GABAA receptors in the CA3 pyramidal neurons.
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| 28. |
- Lam, Matti, et al.
(författare)
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Single cell analysis of autism patient with bi-allelic NRXN1-alpha deletion reveals skewed fate choice in neural progenitors and impaired neuronal functionality
- 2019
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 383:1
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Tidskriftsartikel (refereegranskat)abstract
- We generated human iPS derived neural stem cells and differentiated cells from healthy control individuals and an individual with autism spectrum disorder carrying bi-allelic NRXN1-alpha deletion. We investigated the expression of NRXN1-alpha during neural induction and neural differentiation and observed a pivotal role for NRXN1-alpha during early neural induction and neuronal differentiation. Single cell RNA-seq pinpointed neural stem cells carrying NRXN1-alpha deletion shifting towards radial glia-like cell identity and revealed higher proportion of differentiated astroglia. Furthermore, neuronal cells carrying NRXN1-alpha deletion were identified as immature by single cell RNA-seq analysis, displayed significant depression in calcium signaling activity and presented impaired maturation action potential profile in neurons investigated with electrophysiology. Our observations propose NRXN1-alpha plays an important role for the efficient establishment of neural stem cells, in neuronal differentiation and in maturation of functional excitatory neuronal cells.
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| 29. |
- Netsyk, Olga, et al.
(författare)
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Tonic GABA-activated synaptic and extrasynaptic currents in dentate gyrus granule cells and CA3 pyramidal neurons along the mouse hippocampal dorsoventral axis
- 2020
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Ingår i: Hippocampus. - UK : John Wiley & Sons. - 1050-9631 .- 1098-1063. ; 30:11, s. 1146-1157
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Tidskriftsartikel (refereegranskat)abstract
- The hippocampus is a medial temporal lobe structure in the brain and is widely studied for its role in memory and learning, in particular, spacial memory and emotional responses. It was thought to be a homogenous structure but emerging evidence shows differentiation along the dorsoventral axis and even microdomains for functional and cellular markers. We have examined in two cell‐types of the hippocampal projection neurons, the dentate gyrus (DG) granule cells and CA3 pyramidal neurons, if the GABA‐activated tonic current density varied between the dorsal (septal) and the ventral (temporal) poles of the male mouse hippocampus. Tonic synaptic currents, arising from spontaneous and miniature inhibitory postsynaptic currents (sIPSC, mIPSC), and extrasynaptic tonic currents were evaluated. The results revealed different levels of sIPSC but not mIPSC density between the dorsal and ventral hippocampal neurons for both the DG granule cells and the CA3 pyramidal neurons. The extrasynaptic tonic current density was larger in the DG granule cells as compared to the CA3 pyramidal neurons but did not vary between the dorsal and ventral regions. IPSC bursting was observed in both cell‐types in the ventral hippocampus but was more common in the CA3 pyramidal neurons. Only in the dorsal DG granule cells was the level of the sIPSC and mIPSC density similar. The results indicate that the tonic GABAergic inhibition is particularly strong in the ventral hippocampal DG granule cells and enhanced in the dorsal as compared to the ventral hippocampal CA3 pyramidal neurons.
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| 30. |
- Schuster, Jens, Assistant Professor, 1972-, et al.
(författare)
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Transcriptomes of Dravet syndrome iPSC derived GABAergic cells reveal dysregulated pathways for chromatin remodeling and neurodevelopment
- 2019
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Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961 .- 1095-953X. ; 132
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Tidskriftsartikel (refereegranskat)abstract
- Dravet syndrome (DS) is an early onset refractory epilepsy typically caused by de novo heterozygous variants in SCN1A encoding the a-subunit of the neuronal sodium channel Na(v)1.1. The syndrome is characterized by age related progression of seizures, cognitive decline and movement disorders. We hypothesized that the distinct neurodevelopmental features in DS are caused by the disruption of molecular pathways in Na(v)1.1 haploinsufficient cells resulting in perturbed neural differentiation and maturation. Here, we established DS-patient and control induced pluripotent stem cell derived neural progenitor cells (iPSC NPC) and GABAergic interneuronal (iPSC GABA) cells. The DS-patient iPSC GABA cells showed a shift in sodium current activation and a perturbed response to induced oxidative stress. Transcriptome analysis revealed specific dysregulations of genes for chromatin structure, mitotic progression, neural plasticity and excitability in DS-patient iPSC NPCs and DS-patient iPSC GABA cells versus controls. The transcription factors FOXM1 and E2F1, positive regulators of the disrupted pathways for histone modification and cell cycle regulation, were markedly up-regulated in DS-iPSC GABA lines. Our study highlights transcriptional changes and disrupted pathways of chromatin remodeling in Na(v)1.1 haploinsufficient GABAergic cells, providing a molecular framework that overlaps with that of neurodevelopmental disorders and other epilepsies.
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| 31. |
- Schuster, Jens, Assistant Professor, 1972-, et al.
(författare)
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ZEB2 haploinsufficient Mowat-Wilson syndrome induced pluripotent stem cells show disrupted GABAergic transcriptional regulation and function
- 2022
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Ingår i: Frontiers in Molecular Neuroscience. - : Frontiers Media SA. - 1662-5099. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Mowat-Wilson syndrome (MWS) is a severe neurodevelopmental disorder caused by heterozygous variants in the gene encoding transcription factor ZEB2. Affected individuals present with structural brain abnormalities, speech delay and epilepsy. In mice, conditional loss of Zeb2 causes hippocampal degeneration, altered migration and differentiation of GABAergic interneurons, a heterogeneous population of mainly inhibitory neurons of importance for maintaining normal excitability. To get insights into GABAergic development and function in MWS we investigated ZEB2 haploinsufficient induced pluripotent stem cells (iPSC) of MWS subjects together with iPSC of healthy donors. Analysis of RNA-sequencing data at two time points of GABAergic development revealed an attenuated interneuronal identity in MWS subject derived iPSC with enrichment of differentially expressed genes required for transcriptional regulation, cell fate transition and forebrain patterning. The ZEB2 haploinsufficient neural stem cells (NSCs) showed downregulation of genes required for ventral telencephalon specification, such as FOXG1, accompanied by an impaired migratory capacity. Further differentiation into GABAergic interneuronal cells uncovered upregulation of transcription factors promoting pallial and excitatory neurons whereas cortical markers were downregulated. The differentially expressed genes formed a neural protein-protein network with extensive connections to well-established epilepsy genes. Analysis of electrophysiological properties in ZEB2 haploinsufficient GABAergic cells revealed overt perturbations manifested as impaired firing of repeated action potentials. Our iPSC model of ZEB2 haploinsufficient GABAergic development thus uncovers a dysregulated gene network leading to immature interneurons with mixed identity and altered electrophysiological properties, suggesting mechanisms contributing to the neuropathogenesis and seizures in MWS.
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