Vascular endothelial growth factor (VEGF) is known to be required for the action of antidepressant therapies but its impact on brain synaptic function is poorly characterized. Using a combination of ...electrophysiological, single-molecule imaging and conditional transgenic approaches, we identified the molecular basis of the VEGF effect on synaptic transmission and plasticity. VEGF increases the postsynaptic responses mediated by the N-methyl-D-aspartate type of glutamate receptors (GluNRs) in hippocampal neurons. This is concurrent with the formation of new synapses and with the synaptic recruitment of GluNR expressing the GluN2B subunit (GluNR-2B). VEGF induces a rapid redistribution of GluNR-2B at synaptic sites by increasing the surface dynamics of these receptors within the membrane. Consistently, silencing the expression of the VEGF receptor 2 (VEGFR2) in neural cells impairs hippocampal-dependent synaptic plasticity and consolidation of emotional memory. These findings demonstrated the direct implication of VEGF signaling in neurons via VEGFR2 in proper synaptic function. They highlight the potential of VEGF as a key regulator of GluNR synaptic function and suggest a role for VEGF in new therapeutic approaches targeting GluNR in depression.
Indoor microbial toxicity is suspected to cause some building-related symptoms, but supporting epidemiological data are lacking.
We examined whether the in vitro toxicity of indoor samples from ...school buildings was associated with work-related health symptoms (building-related symptoms, BRS).
Administrators of the Helsinki City Real Estate Department selected 15 schools for the study, and a questionnaire on symptoms connected to work was sent to the teachers in the selected schools for voluntary completion. The cellular toxicity of classroom samples was determined by testing substances extracted from wiped indoor dust and by testing microbial biomass that was cultured on fallout plates. Boar sperm cells were used as indicator cells, and motility loss was the indicator for toxic effects. The effects were expressed as the half maximal effective concentration (EC50) at which >50% of the exposed boar sperm cells were immobile compared to vehicle control.
Completed symptom questionnaires were received from 232 teachers median age, 43 years; 190 (82.3%) women with a median time of 6 years working at their school. Samples from their classrooms were available and were assessed for cellular toxicity. The Poisson regression model showed that the impact of extracts of surface-wiped school classroom dust on teacher work-related BRS was 2.8-fold (95% CI: 1.6–4.9) higher in classrooms with a toxic threshold EC50 of 6µgml−1 versus classrooms with insignificant EC50 values (EC50 >50µgml−1); P<0.001. The number of symptoms that were alleviated during vacation was higher in school classrooms with high sperm toxicity compared to less toxic sites; the RR was 1.9 (95% CI: 1.1–3.3, P=0.03) for wiped dust extracts.
Teachers working in classrooms where the samples showed high sperm toxicity had more BRS. The boar sperm cell motility inhibition assay appears promising as a tool for demonstrating the presence of indoor substances associated with BRS.
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•The causes of building-related symptoms (BRS) at schools are poorly understood.•This epidemiological study examined BRS and the in vitro toxicity of indoor samples.•The toxicity of indoor dust samples and cultured microbial biomass was analyzed.•There was a significant association between BRS and the toxicity results.
Endoplasmic reticulum (ER) and associated signaling pathways are involved in diabetic cardiomyopathy (DCM) however, detailed studies are not available. The present study investigated the role of ER ...stress and related pathways such as ER-phagy, apoptosis and their underlying mechanisms using appropriate models. Beneficial effect of chlorogenic acid was also evaluated against ER stress mediated DCM. H9c2 cells with high glucose (33 mM, in vitro model of hyperglycemia) showed significant activation of ER stress response (GRP78, PERK, IRE1α, ATF6α) and altered its regulatory proteins (PDI, ERO1α). Also, it enhanced ER-phagy through upregulation of Sec62, RTN3 and downregulation of FAM134B. High glucose caused apoptosis via increased levels of CHOP, caspase 12 and calnexin. All these proteins (PERK, IRE1α, ATF6α, RTN3, Sec62 and FAM134B) have been found to have a significant role in the functioning of heart such as excitation contraction coupling and we expect these alterations to induce cardiomyopathy during diabetes. This was confirmed in in vivo study too. High fat, high fructose diet with mild streptozotocin induced diabetic rats showed an increased expression of BNP confirming cardiac injury. We also noticed severe ER stress in the heart of diabetic animals. All these have contributed significantly into alterations in histopathology and increase of weight of the hearts. These findings clearly show that ER stress plays a vital protagonist in the progression of DCM. We also found chlorogenic acid is effective against hyperglycemia induced pathological alteration both in vitro as well as in vivo.
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•Hyperglycemia induces ER stress in H9c2 cells and heart.•Apoptosis by ER phagy and ER stress.•Hyperglycemia causes cardiac injury and hypertrophy.•Chlorogenic acid found to be beneficial against diabetic cardiomyopathy.
Diabetic cardiomyopathy (DCM) is one of the severe complications of diabetes with no known biomarkers for early detection. Mitochondria-associated endoplasmic reticulum membranes (MAM) are less ...studied subcellular targets but an emerging area for exploration in metabolic disorders including DCM. We herein studied the role of MAMs and downstream mitochondrial functions in DCM. We also explored the efficacy of ferulic acid (FeA) against DCM via modulation of MAM and its associated signaling pathway.
The H9c2 cardiomyoblast cells were incubated with high concentration (33 mM) of d-glucose for 48 h to create a high glucose ambience in vitro. The expression of various critical proteins of MAM, mitochondrial function, oxidative phosphorylation (OxPhos) and the genesis of apoptosis were examined. The rats fed with high fat/high fructose/streptozotocin (single dose, i.p.) were used as a diabetic model and analyzed the insulin resistance and markers of cardiac hypertrophy and apoptosis.
High glucose conditions caused the upregulation of MAM formation via PACS2, IP3R2, FUNDC1, and VDAC1 and decreased mitochondrial biogenesis, fusion and OxPhos. The upregulation of mitochondria-driven SMAC-HTRA2-ARTS-XIAP apoptosis and other cell death pathways indicate their critical roles in the genesis of DCM at the molecular level. The diabetic rats also showed cardiomyopathy with increased heart mass index, TNNI3K, troponin, etc. FeA effectively prevented the high glucose-induced MAM alterations and associated cellular anomalies both in vitro and in vivo.
High glucose-induced MAM distortion and subsequent mitochondrial dysfunctions act as the stem of cardiomyopathy. MAM could be explored as a potential target to treat diabetic cardiomyopathy. Also, the FeA could be an attractive nutraceutical agent for diabetic cardiomyopathy.
Schematic representation of the mechanism of diabetic cardiomyopathy by MAM and effect of ferulic acid. High glucose promotes MAM formation via PACS2/IP3R2/FUNDC1/VDAC1 which induces alteration in mitochondrial dynamics, OxPhos leads apoptosis via mitochondria-induced SMAC/HTRA2/ARTS/XIAP inhibition and AIF/ENDOG-Caspase independent pathways in rat cardiomyoblasts which paves the way to diabetic cardiomyopathy. Display omitted
•Hyperglycaemia in H9c2 cells causes distortion of MAMs, contributing significantly to DCM.•MAM distortion causes apoptosis in H9c2 cells via mitochondrial pathways.•Diabetes induces fibrosis and hypertrophy in the heart.•Ferulic acid and metformin are effective against DCM.
Amyloid-β oligomers (Aβo) are the most pathologically relevant Aβ species in Alzheimer's disease (AD), because they induce early synaptic dysfunction that leads to learning and memory impairments. In ...contrast, increasing VEGF (Vascular Endothelial Growth Factor) brain levels have been shown to improve learning and memory processes, and to alleviate Aβ-mediated synapse dysfunction. Here, we designed a new peptide, the blocking peptide (BP), which is derived from an Aβo-targeted domain of the VEGF protein, and investigated its effect on Aβ-associated toxicity. Using a combination of biochemical, 3D and ultrastructural imaging, and electrophysiological approaches, we demonstrated that BP strongly interacts with Aβo and blocks Aβ fibrillar aggregation process, leading to the formation of Aβ amorphous aggregates. BP further impedes the formation of structured Aβo and prevents their pathogenic binding to synapses. Importantly, acute BP treatment successfully rescues long-term potentiation (LTP) in the APP/PS1 mouse model of AD, at an age when LTP is highly impaired in hippocampal slices. Moreover, BP is also able to block the interaction between Aβo and VEGF, which suggests a dual mechanism aimed at both trapping Aβo and releasing VEGF to alleviate Aβo-induced synaptic damage. Our findings provide evidence for a neutralizing effect of the BP on Aβ aggregation process and pathogenic action, highlighting a potential new therapeutic strategy.
•Viral tract-tracing is an added value for multidimensional study of the connectome.•Chains of connected neurons can be visualized in a Golgi staining-like fashion.•SAD and CVS rabies virus strains ...allow detailed visualization of dendritic morphology.•A new fluorescent transneuronal recombinant of CVS-N2c provides Golgi-like labelling.
The introduction of viral transneuronal tracers in the toolbox of neural tract-tracing methods has been an important addition in the field of connectomics for deciphering circuit-level architecture of the nervous system. One of the added values of viral compared to conventional retrograde tracers, in particular of rabies virus, is to provide a Golgi staining-like view of the infected neurons, revealing the thin dendritic arborizations and the spines that are major post-synaptic seats of neuronal connections.
Here, we comparatively illustrate the characteristics of the labeling obtained in the same model system, the basal ganglia circuitry, by different retrograde viral tracing approaches, using the Bartha strain of pseudorabies virus, the SAD and CVS strains of rabies virus and by the conventional retrograde tracer cholera toxin B. To best contrast the differences in the capacity of these tracers to reveal the dendritic morphology in details, we focused on one population of first-order infected neurons in the striatum, which exhibit high spine density, after tracer injection in the substantia nigra.
None of the viruses tested allowed to detect as many neurons as with cholera toxin B, but the SAD and CVS strains of rabies virus had the advantage of enabling detailed Golgi-like visualisation of the dendritic trees, the best numerical detection being offered by the transneuronal rCVS-N2c-P-mCherry while poor labeling was provided by rCVS-N2c-M-GFP. Results also suggest that, besides different viral properties, technical issues about constructs and detection methods contribute to apparently different efficiencies among the viral approaches.
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•Ang II exposure reduced the viability of H9c2 cells.•BDE pre-treatment reduced apoptosis in Ang II exposed cardiac cells.•Elevated levels of Bax, TNF-α and p38MAPK was attenuated by ...BDE in cardiac cells.•BDE mitigated the reduction of Bcl-2 and IL-10 in Ang II exposed heart cells.•BDE treated cells showed reduced levels of caspase-3.
Herein, we investigated the effects of B. diffusa (BDE), a well-known cardiotonic edible medicinal plant against apoptosis in Angiotensin II (Ang II)-stimulated hypertrophic cardiac cells (H9c2). The cells were analyzed for viability, markers of hypertrophy, apoptosis, and the expression of various proteins related to apoptosis. Ang II (100 nM for 48 h)-exposed H9c2 cells treated with BDE (75 μg/ml) showed a significant reduction in apoptosis (58.60%↓) compared to Ang II-alone treated cells. BDE treatment significantly reduced the up-regulation of Bax and cytosolic cytochrome-C caused by Ang II as well as reduced the degree of Ang II- induced down-regulation of Bcl-2. A reduction in caspase-3 activity (33.77%↓) and down-regulation of TNF-α was also observed in BDE treated cells stimulated with Ang II. Furthermore, the up-regulation of phospho-p38 MAPK was attenuated by BDE treatment. Bioactive components in the extract were identified as boeravinone B, quercetin, kaempferol, and caffeic acid as evident from high-performance liquid chromatography (HPLC). Overall, our study shows that B. diffusa is effective in attenuating apoptosis in cardiac cells, which is a major contributor to sudden cardiac death in addition to its nutraceutical properties.
Micromegas in a bulk Giomataris, I.; De Oliveira, R.; Andriamonje, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2006, Letnik:
560, Številka:
2
Journal Article
Recenzirano
Odprti dostop
In this paper, we present a novel way to manufacture the bulk Micromegas detector. A simple process based on the Printed Circuit Board (PCB) technology is employed to produce the entire sensitive ...detector. Such a fabrication process could be extended to very large area detectors made by the industry. The low cost fabrication together with the robustness of the electrode materials will make it attractive for several applications ranging from particle physics and astrophysics to medicine.
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