Wfs1 geeni puudulikkusega hiire monoamiinergilise ja GABA-ergilise süsteemi farmakoloogiline ja käitumuslik iseloomustus

Väitekirja elektrooniline versioon ei sisalda publikatsioone.Meeleolu- ja ärevushäired on laialt levinud väga rasked psühhiaatrilised haigused. Mõnedes inimese geenides esinevate mutatsioonide puhul ilmneb neid häireid oluliselt sagedamini. Üheks selliseks geeniks on WFS1 geen. WFS1 geeni homosügootsed mutatsioonid põhjustavad Wolframi sündroomi (WS), mis on üliharuldane ja väga raske kuluga haigus. Kuigi WS-i iseloomustavad paljud eri sümptomid nagu diabeet, nägemisnärvi kärbumine ja kurtus, on intrigeeriv, et WS-i patsientidel esineb lisaks oluliselt tihemini depressiooni, ärevust ja psühhoose. Lisaks, ka WFS1 heterosügootsetel isikutel on leitud palju suurem risk sattuda haiglasse raske depressiooniga. Nagu inimeses on WFS1 geen, on ka hiires selle analoogina Wfs1 geen. Tulenevalt sellest, et WFS1 geeni mutatsioonid on tihedalt seotud raskete vaimsete häirete tekkega, otsustasime uurida selle geeni puudulikkusest tulenevaid käitumuslikke ja kesknärvisüsteemi muutusi hiiremudelis, millel eelnevalt tekitasime vastavad mutatsioonid Wfs1 geeni. Eesmärk oli vaadata, kas nende mutanthiirte käitumine spetsiaalsetes katseseadmetes peegeldab vaimsete häirete tunnusjooni, mis võimaldaks seda loommudelit kasutada ärevus- ja depressiooniravimite siirdemeditsiinilistes uuringutes näiteks WS-i puhul. Lisaks soovisime teada, millised biokeemilised muutused toimuvad peamistes psühhiaatriliste haigustega seotud virgatsainesüsteemides (dopamiin, serotoniin, noradrenaliin ja GABA) hiire ajus. Esiteks ilmnes, et dopamiini süsteem oli neil hiirtel oluliselt pidurdatud mitmes aspektis. Teiseks ilmnes, et nendel hiirtel on häirunud serotoniini talitlus ja need hiired on tundlikumad laialt levinud serotonergilistele ja noradrenergilistele antidepressantidele (paroksetiin ja imipramiin) depressiooni-laadset seisundit peegeldavates testides. Samas ei tõuse Wfs1-puudulike hiirte serotoniini tasemed ajus vastusena ärevust tekitavale keskkonnale (nt ereda valgusega avaral väljal); pigem isegi langevad. Seevastu mutatsioonita hiirtel serotoniini tasemed tõusevad, mis on üldiselt tavapärane. Kolmandaks leidsime nii käitumuslikke kui geneetilisi muutusi GABA süsteemis, mis võib näidata ärevuse tekkes oluliste mehhanismide kõrvalekaldeid tulenevalt Wfs1 geeni puudulikkusest.Mood and anxiety disorders are prevalent and debilitating psychiatric disorders. Mutations in some human genes are associated with a higher incidence of these disorders. One such gene is WFS1. Homozygous mutations of WFS1 gene cause Wolfram syndrome (WS), a rare and severe disease. Although WS is characterized by multiple different symptoms like diabetes, optic nerve atrophy and deafness, WS patients also have a higher likelihood of depression, anxiety and psychoses. In addition, heterozygous carriers of WFS1 mutations display elevated chance of being hospitalized with depression. Because WFS1 mutations are closely related to debilitating psychiatric disorders, we decided to study the behavioral and biochemical phenotype caused by changes in this gene using a Wfs1-deficient mouse line. The aim was to see if the behavior and biochemical profile of these mutant mice reflects characteristics of human psychiatric disorders and would allow for this mouse model to be used when screening anxiolytic and antidepressant drugs in the field of translational medicine. In addition, we wanted to know which kind of biochemical changes accompany Wfs1 deficiency in neurotransmitter systems (dopamine, serotonin, noradrenaline, GABA) strongly implicated in psychiatric disorders. We first found that these mice had alterations to serotonin metabolism and an elevated reaction to serotonergic antidepressants in behavioral despair experiments. At the same time, brain serotonin levels do not rise in Wfs1-deficient animals in response to exposure to a stress-inducing environment. By contrast, serotonin levels do rise in wild-type animals which is a known response. Secondly, the dopaminergic system is impaired in many aspects in Wfs1 mutants. Thirdly, we detected behavioral and genetic alterations to the GABA system, owing to Wfs1 gene deficiency, which indicate changes to mechanisms important in the etiology of anxiety

Antiviral efficacy of cerium oxide nanoparticles

The authors gratefully acknowledge the financial support by the Estonian Research Council Grants (COVSG2, PRG629, PRG1496), Estonian Centre of Excellence in Research project “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics” TK141 (2014-2020.4.01.15-0011) and University of Tartu Development Fund (PLTFYARENG53). The research was partly conducted using the NAMUR+ core facility funded by projects “Center of nanomaterials technologies and research” (2014-2020.4.01.16-0123) and TT13.Nanomaterials are prospective candidates for the elimination of viruses due to their multimodal mechanisms of action. Here, we tested the antiviral potential of a largely unexplored nanoparticle of cerium dioxide (CeO2). Two nano-CeO2 with opposing surface charge, (+) and (−), were assessed for their capability to decrease the plaque forming units (PFU) of four enveloped and two non-enveloped viruses during 1-h exposure. Statistically significant antiviral activity towards enveloped coronavirus SARS-CoV-2 and influenza virus was registered already at 20 mg Ce/l. For other two enveloped viruses, transmissible gastroenteritis virus and bacteriophage φ6, antiviral activity was evidenced at 200 mg Ce/l. As expected, the sensitivity of non-enveloped viruses towards nano-CeO2 was significantly lower. EMCV picornavirus showed no decrease in PFU until the highest tested concentration, 2000 mg Ce/l and MS2 bacteriophage showed slight non-monotonic response to high concentrations of nano-CeO2(−). Parallel testing of antiviral activity of Ce3+ ions and SiO2 nanoparticles allows to conclude that nano-CeO2 activity was neither due to released Ce-ions nor nonspecific effects of nanoparticulates. Moreover, we evidenced higher antiviral efficacy of nano-CeO2 compared with Ag nanoparticles. This result along with low antibacterial activity and non-existent cytotoxicity of nano-CeO2 allow us to propose CeO2 nanoparticles for specific antiviral applications. © 2022, The Author(s). --//-- This is an open access article Nefedova A, Rausalu K, Zusinaite E, Vanetsev A, Rosenberg M, Koppel K, Lilla S, Visnapuu M, Smits K, Kisand V, Tätte T, Ivask A., "Antiviral efficacy of cerium oxide nanoparticles", Scientific Reports (2022); 12(1):18746, doi: 10.1038/s41598-022-23465-6 published under the CC BY 4.0 licence.Estonian Research Council Grants (COVSG2, PRG629, PRG1496); Estonian Centre of Excellence in Research TK141 (2014-2020.4.01.15-0011); University of Tartu Development Fund (PLTFYARENG53); Institute of Solid-State Physics, University of Latvia has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-Teaming Phase 2 under grant agreement No. 739508, project CAMART2

Promoter-Specific Expression and Genomic Structure of IgLON Family Genes in Mouse

IgLON family is composed of five genes: Lsamp, Ntm, Opcml, Negr1, and Iglon5; encoding for five highly homologous neural adhesion proteins that regulate neurite outgrowth and synapse formation. In the current study we performed in silico analysis revealing that Ntm and Opcml display similar genomic structure as previously reported for Lsamp, characterized by two alternative promotors 1a and 1b. Negr1 and Iglon5 transcripts have uniform 5' region, suggesting single promoter. Iglon5, the recently characterized family member, shares high level of conservation and structural qualities characteristic to IgLON family such as N-terminal signal peptide, three Ig domains, and GPI anchor binding site. By using custom 5'-isoform-specific TaqMan gene-expression assay, we demonstrated heterogeneous expression of IgLON transcripts in different areas of mouse brain and several-fold lower expression in selected tissues outside central nervous system. As an example, the expression of IgLON transcripts in urogenital and reproductive system is in line with repeated reports of urogenital tumors accompanied by mutations in IgLON genes. Considering the high levels of intra-family homology shared by IgLONs, we investigated potential compensatory effects at the level of IgLON isoforms in the brains of mice deficient of one or two family members. We found that the lack of IgLONs is not compensated by a systematic quantitative increase of the other family members. On the contrary, the expression of Ntm 1a transcript and NEGR1 protein was significantly reduced in the frontal cortex of Lsamp-deficient mice suggesting that the expression patterns within IgLON family are balanced coherently. The actions of individual IgLONs, however, can be antagonistic as demonstrated by differential expression of Syp in deletion mutants of IgLONs. In conclusion, we show that the genomic twin-promoter structure has impact on both anatomical distribution and intra-family interactions of IgLON family members. Remarkable variety in the activity levels of 1a and 1b promoters both in the brain and in other tissues, suggests complex functional regulation of IgLONs by alternative signal peptides driven by 1a and 1b promoters.Peer reviewe

Glial cell line-derived neurotrophic factor receptor REarranged during transfection agonist supports dopamine neurons in Vitro and enhances dopamine release In Vivo

Background Motor symptoms of Parkinson's disease (PD) are caused by degeneration and progressive loss of nigrostriatal dopamine neurons. Currently, no cure for this disease is available. Existing drugs alleviate PD symptoms but fail to halt neurodegeneration. Glial cell line-derived neurotrophic factor (GDNF) is able to protect and repair dopamine neurons in vitro and in animal models of PD, but the clinical use of GDNF is complicated by its pharmacokinetic properties. The present study aimed to evaluate the neuronal effects of a blood-brain-barrier penetrating small molecule GDNF receptor Rearranged in Transfection agonist, BT13, in the dopamine system. Methods We characterized the ability of BT13 to activate RET in immortalized cells, to support the survival of cultured dopamine neurons, to protect cultured dopamine neurons against neurotoxin-induced cell death, to activate intracellular signaling pathways both in vitro and in vivo, and to regulate dopamine release in the mouse striatum as well as BT13's distribution in the brain. Results BT13 potently activates RET and downstream signaling cascades such as Extracellular Signal Regulated Kinase and AKT in immortalized cells. It supports the survival of cultured dopamine neurons from wild-type but not from RET-knockout mice. BT13 protects cultured dopamine neurons from 6-Hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridinium (MPP+)-induced cell death only if they express RET. In addition, BT13 is absorbed in the brain, activates intracellular signaling cascades in dopamine neurons both in vitro and in vivo, and also stimulates the release of dopamine in the mouse striatum. Conclusion The GDNF receptor RET agonist BT13 demonstrates the potential for further development of novel disease-modifying treatments against PD. (c) 2019 International Parkinson and Movement Disorder SocietyPeer reviewe

Lipopolysaccharide-Induced Strain-Specific Differences in Neuroinflammation and MHC-I Pathway Regulation in the Brains of Bl6 and 129Sv Mice

Many studies have demonstrated significant mouse-strain-specific differences in behavior and response to pathogenic and pharmacological agents. This study seeks to characterize possible differences in microglia activation and overall severity of neuroinflammation in two widely used mouse strains, C57BL/6NTac (Bl6) and 129S6/SvEvTac (129Sv), in response to acute lipopolysaccharide (LPS) administration. Locomotor activity within the open field arena revealed similar 24 h motor activity decline in both strains. Both strains also exhibited significant bodyweight loss due to LPS treatment, although it was more severe in the Bl6 strain. Furthermore, LPS induced a hypothermic response in Bl6 mice, which was not seen in 129Sv. We found that 24 h LPS challenge significantly increased the inflammatory status of microglia in 129Sv mice. On the other hand, we observed that, under physiological conditions, microglia of Bl6 seemed to be in a higher immune-alert state. Gene and protein expression analysis revealed that LPS induces a significantly stronger upregulation of MHC-I-pathway-related components in the brain of Bl6 compared to 129Sv mice. The most striking difference was detected in the olfactory bulb, where we observed significant LPS-induced upregulation of MHC-I pathway components in Bl6 mice, whereas no alterations were observed in 129Sv. We observed significant positive correlations between bodyweight decline and expressions of MHC-I components in the olfactory bulbs of Bl6 mice and the frontal cortex of 129Sv, highlighting different brain regions most affected by LPS in these strains. Our findings suggest that the brains of Bl6 mice exist in a more immunocompetent state compared to 129Sv mice

Neuroprotective Potential of a Small Molecule RET Agonist in Cultured Dopamine Neurons and Hemiparkinsonian Rats

Background: Parkinson's disease (PD) is a progressive neurological disorder where loss of dopamine neurons in the substantia nigra and dopamine depletion in the striatum cause characteristic motor symptoms. Currently, no treatment is able to halt the progression of PD. Glial cell line-derived neurotrophic factor (GDNF) rescues degenerating dopamine neurons both in vitro and in animal models of PD. When tested in PD patients, however, the outcomes from intracranial GDNF infusion paradigms have been inconclusive, mainly due to poor pharmacokinetic properties. Objective: We have developed drug-like small molecules, named BT compounds that activate signaling through GDNF's receptor, the transmembrane receptor tyrosine kinase RET, both in vitro and in vivo and are able to penetrate through the blood-brain barrier. Here we evaluated the properties of BT44, a second generation RET agonist, in immortalized cells, dopamine neurons and rat 6-hydroxydopamine model of PD. Methods: We used biochemical, immunohistochemical and behavioral methods to evaluate the effects of BT44 on dopamine system in vitro and in vivo. Results: BT44 selectively activated RET and intracellular pro-survival AKT and MAPK signaling pathways in immortalized cells. In primary midbrain dopamine neurons cultured in serum-deprived conditions, BT44 promoted the survival of the neurons derived from wild-type, but not from RET knockout mice. BT44 also protected cultured wild-type dopamine neurons fromMPP+-induced toxicity. In a rat 6-hydroxydopamine model of PD, BT44 reduced motor imbalance and seemed to protect dopaminergic fibers in the striatum. Conclusion: BT44 holds potential for further development into a novel, possibly disease-modifying, therapy for PD.Peer reviewe

Visible light to switch-on desorption from goethite

Switching adsorption–desorption by visible light could provide the possibility for a wide range of applications that require controlled release-on-demand. Here, we demonstrate a visible-light controlled desorption behavior in aqueous suspensions for the first time. We observed cationic dye adsorption on amphoteric goethite α-FeOOH in the dark and release during visible light exposure at a pH value slightly over the isoelectric point of goethite. During this process, the dye does not degrade. Desorption is triggered by local heating due to light absorption in narrow band gap goethite, α-FeOOH

Dopamine System, NMDA Receptor and EGF Family Expressions in Brain Structures of Bl6 and 129Sv Strains Displaying Different Behavioral Adaptation

C57BL/6NTac (Bl6) and 129S6/SvEvTac (129Sv) mice display different coping strategies in stressful conditions. Our aim was to evaluate biomarkers related to different adaptation strategies in the brain of male 129Sv and Bl6 mice. We focused on signaling pathways related to the dopamine (DA) system, N-methyl-D-aspartate (NMDA) receptor and epidermal growth factor (EGF) family, shown as the key players in behavioral adaptation. Mice from Bl6 and 129Sv lines were divided into either home cage controls (HCC group) or exposed to repeated motility testing and treated with saline for 11 days (RMT group). Distinct stress responses were reflected in severe body weight loss in 129Sv and the increased exploratory behavior in Bl6 mice. Besides that, amphetamine caused significantly stronger motor stimulation in Bl6. Together with the results from gene expression (particularly Maob), this study supports higher baseline activity of DA system in Bl6. Interestingly, the adaptation is reflected with opposite changes of DA markers in dorsal and ventral striatum. In forebrain, stress increased the gene expressions of Egf-Erbb1 and Nrg1/Nrg2-Erbb4 pathways more clearly in 129Sv, whereas the corresponding proteins were significantly elevated in Bl6. We suggest that not only inhibited activity of the DA system, but also reduced activity of EGF family and NMDA receptor signaling underlies higher susceptibility to stress in 129Sv. Altogether, this study underlines the better suitability of 129Sv for modelling neuropsychiatric disorders than Bl6

A Straightforward and “Green” Solvothermal Synthesis of Al Doped Zinc Oxide Plasmonic Nanocrystals and Piezoresistive Elastomer Nanocomposite

Plasmonic oxide nanocrystals hold great promise in a wide range of applications, for which the availability of scalable and “green” synthesis methods is prerequisite, whereas until recently an excellent response has been demonstrated only for samples prepared through intricate synthesis paths. We report here a simple ethanol solvothermal synthesis route of Al doped ZnO plasmonic nanocrystals (Zn1xAlxO) at doping levels of x up to 0.15. The obtained Al doped ZnO samples consisted of nanoparticles and short nanorods with a diameter of around 10 nm at x ¼ 0.15 doping level while reaching aspect ratio levels of 50 for lower doping levels. Detailed structural studies using powder X-ray diffraction Rietveld refinement, X-ray absorption and photoelectron spectroscopies show that all samples maintain the structure of the phase-pure zincite with the space group P63mc. The resulting powders exhibit strong infrared absorption while remaining largely transparent for visible light, enabling the preparation of transparent colloidal dispersions. Furthermore, as a test of applicability in a practical device, the nanocrystals were used to prepare transparent piezoresistive Zn0.925Al0.075O–polydimethylsiloxane composites. The prepared sensor material exhibits excellent repeatable and reproducible piezoresistive behaviour

Altered Expression Profile of IgLON Family of Neural Cell Adhesion Molecules in the Dorsolateral Prefrontal Cortex of Schizophrenic Patients

Neural adhesion proteins are crucial in the development and maintenance of functional neural connectivity. Growing evidence suggests that the IgLON family of neural adhesion molecules LSAMP, NTM, NEGR1, and OPCML are important candidates in forming the susceptibility to schizophrenia (SCZ). IgLON proteins have been shown to be involved in neurite outgrowth, synaptic plasticity and neuronal connectivity, all of which have been shown to be altered in the brains of patients with the diagnosis of schizophrenia. Here we optimized custom 5′-isoform-specific TaqMan gene-expression analysis for the transcripts of human IgLON genes to study the expression of IgLONs in the dorsolateral prefrontal cortex (DLPFC) of schizophrenic patients (n = 36) and control subjects (n = 36). Uniform 5′-region and a single promoter was confirmed for the human NEGR1 gene by in silico analysis. IgLON5, a recently described family member, was also included in the study. We detected significantly elevated levels of the NEGR1 transcript (1.33-fold increase) and the NTM 1b isoform transcript (1.47-fold increase) in the DLPFC of schizophrenia patients compared to healthy controls. Consequent protein analysis performed in male subjects confirmed the increase in NEGR1 protein content both in patients with the paranoid subtype and in patients with other subtypes. In-group analysis of patients revealed that lower expression of certain IgLON transcripts, mostly LSAMP 1a and 1b, could be related with concurrent depressive endophenotype in schizophrenic patients. Additionally, our study cohort provides further evidence that cannabis use may be a relevant risk factor associated with suicidal behaviors in psychotic patients. In conclusion, we provide clinical evidence of increased expression levels of particular IgLON family members in the DLPFC of schizophrenic patients. We propose that alterations in the expression profile of IgLON neural adhesion molecules are associated with brain circuit disorganization in neuropsychiatric disorders, such as schizophrenia. In the light of previously published data, we suggest that increased level of NEGR1 in the frontal cortex may serve as molecular marker for a wider spectrum of psychiatric conditions