Spontaneous Release Research Articles

An attenuated herpesvirus vectored vaccine candidate induces T-cell responses against highly conserved porcine reproductive and respiratory syndrome virus M and NSP5 proteins that are unable to control infection.

Porcine reproductive and respiratory syndrome virus (PRRSV) remains a leading cause of economic loss in pig farming worldwide. Existing commercial vaccines, all based on modified live or inactivated PRRSV, fail to provide effective immunity against the highly diverse circulating strains of both PRRSV-1 and PRRSV-2. Therefore, there is an urgent need to develop more effective and broadly active PRRSV vaccines. In the absence of neutralizing antibodies, T cells are thought to play a central role in controlling PRRSV infection. Herpesvirus-based vectors are novel vaccine platforms capable of inducing high levels of T cells against encoded heterologous antigens. Therefore, the aim of this study was to assess the immunogenicity and efficacy of an attenuated herpesvirus-based vector (bovine herpesvirus-4; BoHV-4) expressing a fusion protein comprising two well-characterized PRRSV-1 T-cell antigens (M and NSP5). Prime-boost immunization of pigs with BoHV-4 expressing the M and NSP5 fusion protein (vector designated BoHV-4-M-NSP5) induced strong IFN-γ responses, as assessed by ELISpot assays of peripheral blood mononuclear cells (PBMC) stimulated with a pool of peptides representing PRRSV-1 M and NSP5. The responses were closely mirrored by spontaneous IFN-γ release from unstimulated cells, albeit at lower levels. A lower frequency of M and NSP5 specific IFN-γ responding cells was induced following a single dose of BoHV-4-M-NSP5 vector. Restimulation using M and NSP5 peptides from PRRSV-2 demonstrated a high level of cross-reactivity. Vaccination with BoHV-4-M-NSP5 did not affect viral loads in either the blood or lungs following challenge with the two heterologous PRRSV-1 strains. However, the BoHV-4-M-NSP5 prime-boost vaccination showed a marked trend toward reduced lung pathology following PRRSV-1 challenge. The limited effect of T cells on PRRSV-1 viral load was further examined by analyzing local and circulating T-cell responses using intracellular cytokine staining and proliferation assays. The results from this study suggest that vaccine-primed T-cell responses may have helped in the control of PRRSV-1 associated tissue damage, but had a minimal, if any, effect on controlling PRRSV-1 viral loads. Together, these results indicate that future efforts to develop effective PRRSV vaccines should focus on achieving a balanced T-cell and antibody response.

Reversible modulation of protocell volume via collective response of functional protein in its membrane

Volume change plays an important role in biological cells to regulate their internal microenvironment. To adapt to the rapid variation of the surface area during the volume change, the lipid membrane is dynamically modulated via membrane folding invagination, or spontaneous uptake or release of lipid molecules under osmotic pressure. Here, we demonstrate an alternative approach to design a functional protocellular system capable of dynamically adjusting its volume and intracellular microenvironment in response to the alteration of pH. By assembling and subsequently cross-linking pH-responsive caseinate at the water–oil interface, the caseinate-based protocell with more than ten thousand caseinate units in its membrane was established and showed a reversible volume and pore size change to pH variation due to the collective response of the caseinate in the membrane, which could be used to control the spatial distribution of proto-organelle by regulating of the viscosity inside the protocell.

EAAT5 glutamate transporter rapidly binds glutamate with micromolar affinity in mouse rods.

Light responses of rod photoreceptor cells in the retina are encoded by changes in synaptic glutamate release that is in turn shaped by reuptake involving EAAT5 plasma membrane glutamate transporters. Heterologously expressed EAAT5 activates too slowly upon glutamate binding to support significant uptake. We tested EAAT5 activation in mouse rods in vivo by stimulating glutamate transporter anion currents (IA(glu)) with UV flash photolysis of MNI-glutamate, varying flash intensity to vary glutamate levels. Responses to uncaging rose rapidly with time constants of 2-3 ms, similar to IA(glu) events arising from spontaneous release. Spontaneous release events and IA(glu) evoked by weak flashes also declined with similar time constants of 40-50 ms. Stronger flashes evoked responses that decayed more slowly. Time constants were twofold faster at 35°C, suggesting that they reflect transporter kinetics, not diffusion. Selective EAAT1 and EAAT2 inhibitors had no significant effect, suggesting IA(glu) in rods arises solely from EAAT5. We calibrated glutamate levels attained during flash photolysis by expressing a fluorescent glutamate sensor iGluSnFr in cultured epithelial cells. We compared fluorescence at different glutamate concentrations to fluorescence evoked by photolytic uncaging of MNI-glutamate. The relationship between flash intensity and glutamate yielded EC50 values for EAAT5 amplitude, decay time, and rise time of ∼10 μM. Micromolar affinity and rapid activation of EAAT5 in rods show it can rapidly bind synaptic glutamate. However, we also found that EAAT5 currents are saturated by the synchronous release of only a few vesicles, suggesting limited capacity and a role for glial uptake at higher release rates.

Dynamic mechanical properties of veined rocks under biaxial confinement

As the global demand for minerals continues to rise, mining operations deepen, and major risks arise from extreme geomechanical conditions. One risk of major concern is strainburst, a complex event characterized by the spontaneous release of energy at the limits of excavations triggered by dynamic disturbances such as blasting and induced seismicity. To study this phenomenon, we ran coupled static-dynamic tests performed under uniaxial and biaxial confinement in a Triaxial Hopkinson bar system. We used veined-rock samples from one of the largest underground mines in the world: El Teniente (Chile). Additionally, a high-speed camera was employed to study the role of dynamic loads and high strain rates (10-102 s−1) on the fracture pattern propagation. Our results show an increase in elastic modulus after increasing σ2 pre-stress. Two types of post-peak curves: I and II, were identified. While type I is related to fractures for which the sample does not lose the load capacity in a biaxial confinement state, type II is associated with the fragmentation and expulsion of fragments from the free faces of the tested samples. In addition, we observed that fracture propagation is controlled by veinlets that exhibit a favorable orientation in relation to the direction of the dynamic load. Moreover, two rockburst-related phenomena are observed: slab buckling, and rapid fragment ejection. Our findings suggest that fracture propagation occurs through the rock matrix when the mechanical properties exhibit a strong dependence on the strain rate. When this dependence is less evident, they are restricted to the veinlets. If a dynamic pulse generates deformation rates between 10 to 102 s−1, stiffness increases, and therefore energy dissipation increases as well. When combined with the predisposition of veined rocks to form blocks, these conditions create favorable environments for strainburst occurrences and may exacerbate the severity of this phenomenon in underground excavations.

In vitro evaluation of immune responses to bacterial hydrogels for the development of living therapeutic materials

In living therapeutic materials (LTMs), organisms genetically programmed to produce and deliver drugs are encapsulated in porous matrices acting as physical barriers between the therapeutic organisms and the host cells. LTMs consisting of engineered E. coli encapsulated in Pluronic F127-based hydrogels have been frequently used in LTM designs but their immunogenicity has not been tested. In this study, we investigate the response of human peripheral blood mononuclear cells (PBMCs) exposed to this bacteria/hydrogel combination. The release of inflammation-related cytokines and cytotoxic proteins and the subsets of natural killer cells and T cells were examined. Encapsulation of the bacteria in hydrogels considerably lowers their immunogenicity. ClearColi, an endotoxin-free variant of E. coli, did not polarize NK cells into the more cytolytic CD16dim subset as E. coli. Our results demonstrate that ClearColi-encapsulated hydrogels generate low immunogenic response and are suitable candidates for the development of LTMs for in vivo testing to assess a potential clinical use. Nevertheless, we observed a stronger immune response (elevated levels of IFNγ, IL-6 and cytotoxic proteins) in pro-inflammatory PBMCs characterized by a high spontaneous release of IL-2. This highlights the need to identify recipients who have a higher likelihood of experiencing undesired immune responses to LTMs with IL-2 serving as a potential predictive marker. Additionally, including anti-inflammatory measures in living therapeutic material designs could be beneficial for such recipients.

Stress increases the spontaneous release of ACh and may be involved in the generation and maintenance of myofascial trigger points in mouse

An increase in spontaneous neurotransmission may be related to myofascial pain. Sympathetic neurons innervate most of the neuromuscular junction sand are involved in the modulation of synaptic transmission. Therefore, a direct action of stress on acetylcholine release is expected. For this reason, this study aims to evaluate the relationship between stress and spontaneous neurotransmission. Five acute stressors (immobilization, forced swimming, food and water deprivation, social isolation and ultrasound) were tested in 6 weeks adult Swiss male mice. Subsequently, these types of stress were combined to generate a model of chronic stress. The study of ACh release was evaluated before and after the application of stress by intracellular recording of spontaneous neurotransmission (mEPPs). In each one of the stressors, an increase in the frequency of mEPPs was obtained immediately after treatment, which remained elevated for 5 days and thereafter returned to control values after a week. With chronic stress, a much higher increase in the frequency of mEPPs was obtained and it was maintained for 15 days. In summary, stress, both in its acute and chronic forms, increased spontaneous neurotransmission significantly. There is a possibility that chronic stress is related with the genesis or maintenance of myofascial pain.

Ca2+ and cAMP open differentially dilating synaptic fusion pores.

Neuronal dense-core vesicles (DCVs) contain neuropeptides and much larger proteins that affect synaptic growth and plasticity. Rather than using full collapse exocytosis that commonly mediates peptide hormone release by endocrine cells, DCVs at the Drosophila neuromuscular junction release their contents via fusion pores formed by kiss-and-run exocytosis. Here, we used fluorogen-activating protein (FAP) imaging to reveal the permeability range of synaptic DCV fusion pores and then show that this constraint is circumvented by cAMP-induced extra fusions with dilating pores that result in DCV emptying. These Ca2+-independent full fusions require PKA-R2, a PKA phosphorylation site on Complexin and the acute presynaptic function of Rugose, the homolog of mammalian neurobeachin, a PKA-R2 anchor implicated in learning and autism. Therefore, localized Ca2+-independent cAMP signaling opens dilating fusion pores to release large cargoes that cannot pass through the narrower fusion pores that mediate spontaneous and activity-dependent neuropeptide release. These results imply that the fusion pore is a variable filter that differentially sets the composition of proteins released at the synapse by independent exocytosis triggers responsible for routine peptidergic transmission (Ca2+) and synaptic development (cAMP).

Bilateral Spontaneous Release of Vitreomacular Traction

Bilateral Spontaneous Release of Vitreomacular Traction

Spontaneous Neutrophil Extracellular Traps Release Are Inflammatory Markers Associated with Hyperglycemia and Renal Failure on Diabetic Retinopathy.

Diabetic retinopathy (DR) is the major microvascular complication of diabetes and causes vitreous traction and intraretinal hemorrhages leading to retinal detachment and total blindness. The evolution of diabetes is related to exacerbating inflammation caused by hyperglycemia and activation of inflammatory cells. Neutrophils are cells able to release structures of extracellular DNA and proteolytic enzymes called extracellular traps (NETs), which are associated with the persistence of inflammation in chronic pathologies. The purpose of the study was to determine the usefulness of neutrophil traps as indicators of DR progression in patients with type 2 diabetes (T2DM). We performed a case-control study of seventy-four cases classified into five groups (non-proliferative DR, mild, moderate, severe, and proliferative) and fifteen healthy controls. We found correlations between NETs and a diagnostic time of T2DM (r = 0.42; p < 0.0001), fasting glucose (r = 0.29; p < 0.01), glycated hemoglobin (HbA1c) (r = 0.31; p < 0.01), estimated glomerular filtration rate (eGFR) (r = -0.29; p < 0.01), and plasma osmolarity (r = 0.25; p < 0.01). These results suggest that due to NETs being associated with clinical indicators, such as HbA1c and eGFR, and that NETs are also associated with DR, clinical indicators might be explained in part through an NET-mediated inflammation process.

Properties and cellular uptake of photo-triggered mixed metallosurfactant vesicles intended for controlled CO delivery in gas therapy

The scientific relevance of carbon monoxide has increased since it was discovered that it is a gasotransmitter involved in several biological processes. This fact stimulated research to find a secure and targeted delivery and lead to the synthesis of CO-releasing molecules. In this paper we present a vesicular CO delivery system triggered by light composed of a synthetized metallosurfactant (TCOL10) with two long carbon chains and a molybdenum-carbonyl complex. We studied the characteristics of mixed TCOL10/phosphatidylcholine metallosomes of different sizes. Vesicles from 80 to 800 nm in diameter are mainly unilamellar, do not disaggregate upon dilution, in the dark are physically and chemically stable at 4 °C for at least one month, and exhibit a lag phase of about 4 days before they show a spontaneous CO release at 37 °C. Internalization of metallosomes by cells was studied as function of the incubation time, and vesicle concentration and size. Results show that large vesicles are more efficiently internalized than the smaller ones in terms of the percentage of cells that show TCOL10 and the amount of drug that they take up. On balance, TCOL10 metallosomes constitute a promising and viable approach for efficient delivery of CO to biological systems.

Lysosomal calcium loading promotes spontaneous calcium release by potentiating ryanodine receptors

Spontaneous calcium release by ryanodine receptors (RyRs) due to intracellular calcium overload results in delayed afterdepolarizations, closely associated with life-threatening arrhythmias. In this regard, inhibiting lysosomal calcium release by two-pore channel 2 (TPC2) knockout has been shown to reduce the incidence of ventricular arrhythmias under β-adrenergic stimulation. However, mechanistic investigations into the role of lysosomal function on RyR spontaneous release remain missing. We investigate the calcium handling mechanisms by which lysosome function modulates RyR spontaneous release, and determine how lysosomes are able to mediate arrhythmias by its influence on calcium loading. Mechanistic studies were conducted using a population of biophysically detailed mouse ventricular models including for the first time modeling of lysosomal function, and calibrated by experimental calcium transients modulated by TPC2. We demonstrate that lysosomal calcium uptake and release can synergistically provide a pathway for fast calcium transport, by which lysosomal calcium release primarily modulates sarcoplasmic reticulum calcium reuptake and RyR release. Enhancement of this lysosomal transport pathway promoted RyR spontaneous release by elevating RyR open probability. In contrast, blocking either lysosomal calcium uptake or release revealed an antiarrhythmic impact. Under conditions of calcium overload, our results indicate that these responses are strongly modulated by intercellular variability in L-type calcium current, RyR release, and sarcoplasmic reticulum calcium-ATPase reuptake. Altogether, our investigations identify that lysosomal calcium handling directly influences RyR spontaneous release by regulating RyR open probability, suggesting antiarrhythmic strategies and identifying key modulators of lysosomal proarrhythmic action.

Astrocyte Calcium Signaling Shifts the Polarity of Presynaptic Plasticity

Astrocytes have been increasingly acknowledged to play active roles in regulating synaptic transmission and plasticity. Through a variety of metabotropic and ionotropic receptors expressed on their surface, astrocytes detect extracellular neurotransmitters, and in turn, release gliotransmitters to modify synaptic strength, while they can also alter neuronal membrane excitability by modulating extracellular ionic milieu. Given the seemingly large repertoire of synaptic modulation, when, where and how astrocytes interact with synapses remain to be fully understood. Previously, we have identified a role for astrocyte NMDA receptor and L-VGCCs signaling in heterosynaptic presynaptic plasticity and promoting the heterogeneity of presynaptic strengths at hippocampal synapses. Here, we have sought to further clarify the mode by which astrocytes regulate presynaptic plasticity by exploiting a reduced culture system to globally evoke NMDA receptor-dependent presynaptic plasticity. Recording from a postsynaptic neuron intracellularly loaded with BAPTA, briefly bath applying NMDA and glycine induces a stable decrease in the rate of spontaneous glutamate release, which requires the presence of astrocytes and the activation of A1 adenosine receptors. Upon preventing astrocyte calcium signaling or blocking L-VGCCs, NMDA + glycine application triggers an increase, rather than a decrease, in the rate of spontaneous glutamate release, thereby shifting the presynaptic plasticity to promote an increase in strength. Our findings point to a crucial and surprising role of astrocytes in controlling the polarity of NMDA receptor and adenosine-dependent presynaptic plasticity. Such a pivotal mechanism unveils the power of astrocytes in regulating computations performed by neural circuits and is expected to profoundly impact cognitive processes.

RYR2-ryanodinopathies: from calcium overload to calcium deficiency.

The sarcoplasmatic reticulum (SR) cardiac ryanodine receptor/calcium release channel RyR2 is an essential regulator of cardiac excitation-contraction coupling and intracellular calcium homeostasis. Mutations of the RYR2 are the cause of rare, potentially lethal inherited arrhythmia disorders. Catecholaminergic polymorphic ventricular tachycardia (CPVT) was first described more than 20 years ago and is the most common and most extensively studied cardiac ryanodinopathy. Over time, other distinct inherited arrhythmia syndromes have been related to abnormal RyR2 function. In addition to CPVT, there are at least two other distinct RYR2-ryanodinopathies that differ mechanistically and phenotypically from CPVT: RYR2 exon-3 deletion syndrome and the recently identified calcium release deficiency syndrome (CRDS). The pathophysiology of the different cardiac ryanodinopathies is characterized by complex mechanisms resulting in excessive spontaneous SR calcium release or SR calcium release deficiency. While the vast majority of CPVT cases are related to gain-of-function variants of the RyR2 protein, the recently identified CRDS is linked to RyR2 loss-of-function variants. The increasing number of these cardiac 'ryanodinopathies' reflects the complexity of RYR2-related cardiogenetic disorders and represents an ongoing challenge for clinicians. This state-of-the-art review summarizes our contemporary understanding of RYR2-related inherited arrhythmia disorders and provides a systematic and comprehensive description of the distinct cardiac ryanodinopathies discussing clinical aspects and molecular insights. Accurate identification of the underlying type of cardiac ryanodinopathy is essential for the clinical management of affected patients and their families.

Spontaneous and multifaceted ATP release from astrocytes at the scale of hundreds of synapses.

Astrocytes participate in information processing by releasing neuroactive substances termed gliotransmitters, including ATP. Individual astrocytes come into contact with thousands of synapses with their ramified structure, but the spatiotemporal dynamics of ATP gliotransmission remains unclear, especially in physiological brain tissue. Using a genetically encoded fluorescent sensor, GRABATP1.0 , we discovered that extracellular ATP increased locally and transiently in absence of stimuli in neuron-glia co-cultures, cortical slices, and the anesthetized mouse brain. Spontaneous ATP release events were tetrodotoxin-insensitive but suppressed by gliotoxin, fluorocitrate, and typically spread over 50-250 μm2 area at concentrations capable of activating purinergic receptors. Besides, most ATP events did not coincide with Ca2+ transients, and intracellular Ca2+ buffering with BAPTA-AM did not affect ATP event frequency. Clustering analysis revealed that these events followed multiple distinct kinetics, and blockade of exocytosis only decreased a minor group of slow events. Overall, astrocytes spontaneously release ATP through multiple mechanisms, mainly in non-vesicular and Ca2+ -independent manners, thus potentially regulating hundreds of synapses all together.

Activation of molecular oxygen over binuclear iron centers in Al-rich *BEA zeolite

Here, we present the unique redox properties of distant binuclear iron centers in Al-rich *BEA zeolite in O2 splitting and CH4 oxidation. Al-rich *BEA was obtained via a template-free synthesis procedure guaranteeing low-defected structure and a high fraction of Al-pairs enabling stabilization of binuclear iron centers. By employment of a multispectroscopic in-situ approach (Mössbauer and X-ray absorption) the formation of active oxygen over binuclear iron centers in Al-rich *BEA was confirmed and subsequent CH4 oxidation was studied. Spontaneous release of the reaction products to the gas stream, representing a significant advantage of the studied system, was proved by the results of in-situ FTIR and mass spectrometry. This is the first experimental proof of the formation of fully-functioned binuclear iron centers (able to split O2, stabilize active oxygen forms, and subsequently oxidize CH4) in zeolite of *BEA topology.

PLC regulates spontaneous glutamate release triggered by extracellular calcium and readily releasable pool size in neocortical neurons.

Dynamic physiological changes in brain extracellular calcium ([Ca2+]o) occur when high levels of neuronal activity lead to substantial Ca2+ entry via ion channels reducing local [Ca2+]o. Perturbations of the extracellular microenvironment that increase [Ca2+]o are commonly used to study how [Ca2+] regulates neuronal activity. At excitatory synapses, the Ca2+-sensing receptor (CaSR) and other G-protein coupled receptors link [Ca2+]o and spontaneous glutamate release. Phospholipase C (PLC) is activated by G-proteins and is hypothesized to mediate this process. Patch-clamping cultured neocortical neurons, we tested how spontaneous glutamate release was affected by [Ca2+]o and inhibition of PLC activity. We used hypertonic sucrose (HS) to evaluate the readily releasable pool (RRP) and test if it was affected by inhibition of PLC activity. Spontaneous glutamate release substantially increased with [Ca2+]o, and inhibition of PLC activity, with U73122, abolished this effect. PLC-β1 is an abundant isoform in the neocortex, however, [Ca2+]o-dependent spontaneous release was unchanged in PLC-β1 null mutants (PLC-β1-/-). U73122 completely suppressed this response in PLC-β1-/- neurons, indicating that this residual [Ca2+]o-sensitivity may be mediated by other PLC isoforms. The RRP size was substantially reduced after incubation in U73122, but not U73343. Phorbol esters increased RRP size after PLC inhibition. Together these data point to a strong role for PLC in mediating changes in spontaneous release elicited by [Ca2+]o and other extracellular cues, possibly by modifying the size of the RRP.

Photoactive intragastric satiety-inducing device using polymeric photosensitizers for minimally invasive weight loss treatment

An intragastric satiety-inducing device (ISD) located in the stomach induce satiety and fullness in the absence of food by continuously pressing on the distal esophagus and cardia of the stomach. To improve the therapeutic function of ISD, Chlorin e6 (Ce6) was embedded in a disk portion of ISD, generating reactive oxygen species and stimulating endocrine cells under the laser irradiation. Since Ce6 has remarkable light efficiency but poor solubility in various solvents, it is essential to use a polymeric photosensitizer and optimize a suitable coating solution composition. Methoxy polyethylene glycol-Ce6 was uniformly coated and the spontaneous release amount of the Ce6 from the device could be reduced, which induced photo-responsive cell death and reduced ghrelin levels in vitro. In mini pigs operated single therapy (PDT or ISD) or combination therapy (Photoreactive ISD), there were differences in body weight (control: 28% vs. Photoreactive ISD: 4%, P < 0.001), ghrelin (control: 4% vs. Photoreactive ISD: 35%, P < 0.001), and leptin levels (control: 8% vs. Photoreactive PDT: 35%, P < 0.001) at 4 weeks.

Spontaneous release of epiretinal membrane in a patient with a retinal vasoproliferative tumor

A 36-year-old woman was scheduled for a vitrectomy of her left eye due to an epiretinal membrane (ERM) secondary to a retinal vasoproliferative tumor. Visual acuity (VA) was 20/20 in the right eye and 20/80 in the left. Before surgery, the patient’s vision had improved (20/20). Fundus examination and tomographic images revealed the spontaneous release of the ERM. ERM release usually presents after cryotherapy and photocoagulation. This is the first case in the literature documenting spontaneous ERM release in a vasoproliferarive tumor.

Microtubule depolymerization contributes to spontaneous neurotransmitter release in vitro

Microtubules are key to multiple neuronal functions involving the transport of organelles, however, their relationship to neurotransmitter release is still unresolved. Here, we show that microtubules present in the presynaptic compartment of cholinergic autaptic synapses are dynamic. To investigate how the balance between microtubule growth and shrinkage affects neurotransmission we induced synchronous microtubule depolymerization by photoactivation of the chemical inhibitor SBTub3. The consequence was an increase in spontaneous neurotransmitter release. An analogous effect was obtained by dialyzing the cytosol with Kif18A, a plus-end-directed kinesin with microtubule depolymerizing activity. Kif18A also inhibited the refilling of the readily releasable pool of synaptic vesicles during high frequency stimulation. The action of Kif18A was associated to one order of magnitude increases in the numbers of exo-endocytic pits and endosomes present in the presynaptic terminal. An enhancement of spontaneous neurotransmitter release was also observed when neurons were dialyzed with stathmin-1, a protein with a widespread presence in the nervous system that induces microtubule depolymerization. Taken together, these results support that microtubules restrict spontaneous neurotransmitter release as well as promote the replenishment of the readily releasable pool of synaptic vesicles.

Nanoelectrochemistry reveals how soluble Aβ42 oligomers alter vesicular storage and release of glutamate

Glutamate (Glu) is the major excitatory transmitter in the nervous system. Impairment of its vesicular release by β-amyloid (Aβ) oligomers is thought to participate in pathological processes leading to Alzheimer's disease. However, it remains unclear whether soluble Aβ42 oligomers affect intravesicular amounts of Glu or their release in the brain, or both. Measurements made in this work on single Glu varicosities with an amperometric nanowire Glu biosensor revealed that soluble Aβ42 oligomers first caused a dramatic increase in vesicular Glu storage and stimulation-induced release, accompanied by a high level of parallel spontaneous exocytosis, ultimately resulting in the depletion of intravesicular Glu content and greatly reduced release. Molecular biology tools and mouse models of Aβ amyloidosis have further established that the transient hyperexcitation observed during the primary pathological stage is mediated by an altered behavior of VGLUT1 responsible for transporting Glu into synaptic vesicles. Thereafter, an overexpression of Vps10p-tail-interactor-1a, a protein that maintains spontaneous release of neurotransmitters by selective interaction with t-SNAREs, resulted in a depletion of intravesicular Glu content, triggering advanced-stage neuronal malfunction. These findings are expected to open perspectives for remediating Aβ42-induced neuronal hyperactivity and neuronal degeneration.