Protein SV2A Research Articles

Tracing synaptic loss in Alzheimer's brain with SV2A PET-tracer UCB-J.

Synaptic loss is an early prominent feature of Alzheimer's disease (AD). The recently developed novel synaptic vesicle 2A protein (SV2A) PET-tracer UCB-J has shown great promise in tracking synaptic loss in AD. However, there have been discrepancies between the findings and a lack of mechanistic insight. Here we report the first extensive pre-clinical validation studies for UCB-J in control (CN; n=11) and AD (n=11) brains using a multidimensional approach of post-mortem brain imaging techniques, radioligand binding, and biochemical studies. We demonstrate that UCB-J could target SV2A protein with high specificity and depict synaptic loss at synaptosome levels in AD brain regions compared to CNs. UCB-J showed highest synaptic loss in AD hippocampus followed in descending order by frontal cortex, temporal cortex, parietal cortex, and cerebellum. 3H-UCB-J large brain-section autoradiography and cellular/subcellular fractions binding studies indicated potential off-target interaction with phosphorylated tau (p-tau) species in AD brains, which could have subsequent clinical implications for imaging studies. Synaptic positron emission tomography (PET)-tracer UCB-J could target synaptic vesicle 2A protein (SV2A) with high specificity in Alzheimer's disease (AD) and control brains. Synaptic PET-tracer UCB-J could depict synaptic loss at synaptosome levels in AD brain regions compared to control. Potential off-target interaction of UCB-J with phosphorylated tau (p-tau) species at cellular/subcellular levels could have subsequent clinical implications for imaging studies, warranting further investigations.

A study to determine the mechanisms underlying changes in synaptic vesicle glycoprotein 2A density in Alzheimer’s disease

AbstractBackgroundSynaptic vesicle glycoprotein 2A (SV2A) is a transmembrane synaptic vesicle protein that regulates vesicle exocytosis and neurotransmitter release. Positron emission tomography (PET) studies reveal that the levels of SV2A are decreased in the brains of patients with Alzheimer’s disease (AD) and other brain disorders. Whether changes in SV2A PET signal are caused by a loss of synapses or a loss of SV2A protein is unclear and an impediment to developing novel treatments for neurodegenerative diseases. The goal of this study is to determine the biological underpinnings of reduced SV2A signal in individuals with AD.MethodWe examined post‐mortem brain samples from the entorhinal cortex (EC) and cerebellum (CBM) in AD patients and age‐ and sex‐matched controls without neurological conditions (EC n = 19 AD, 15 controls; CBM n = 11 AD, 12 controls). We explored differences in synaptic density and synaptic ultrastructure using array tomography and electron microscopy, and analyzed data using linear mixed‐effects models (with post‐hoc Tukey comparisons) and Spearman correlations.ResultSV2A puncta density measured with array tomography in both brain regions strongly correlates with synaptophysin puncta density, the gold standard marker for synapse density in post‐mortem brain tissue (ñ = 0.87 EC, ñ = 0.72 CBM, p<0.001 both regions). We observed lower SV2A puncta density in AD cases compared to controls in EC (p = 0.001), slightly higher SV2A puncta density in AD in CBM (p = 0.02), and no difference in the proportion of synaptophysin puncta labelled with SV2A in AD vs control (p = 0.37). Electron microscopy revealed immunogold labelled SV2A protein localized specifically to presynaptic vesicles and no difference in the number of immuno‐gold labelled SV2A particles per synapse.ConclusionOur data indicate that the loss of SV2A PET signal reported in vivo in patients with AD is likely caused by a loss of synapses and not the loss of SV2A protein within remaining synapses. These findings indicate that changes in SV2A PET signal are due to synaptic loss and that strategies for reversing synaptic loss or associated neuropathophysiological effects may be important to the treatment of AD and other synaptopathies. This work is part of the SV2A PET Project, a program of the FNIH Biomarker Consortium.

PET imaging of synaptic density in Parkinsonian disorders.

Synaptic dysfunction and altered synaptic pruning are present in people with Parkinsonian disorders. Dopamine loss and alpha-synuclein accumulation, two hallmarks of Parkinson's disease (PD) pathology, contribute to synaptic dysfunction and reduced synaptic density in PD. Atypical Parkinsonian disorders are likely to have unique spatiotemporal patterns of synaptic density, differentiating them from PD. Therefore, quantification of synaptic density has the potential to support diagnoses, monitor disease progression, and treatment efficacy. Novel radiotracers for positron emission tomography which target the presynaptic vesicle protein SV2A have been developed to quantify presynaptic density. The radiotracers have successfully investigated synaptic density in preclinical models of PD and people with Parkinsonian disorders. Therefore, this review will summarize the preclinical and clinical utilization of SV2A radiotracers in people with Parkinsonian disorders. We will evaluate how SV2A abundance is associated with other imaging modalities and the considerations for interpreting SV2A in Parkinsonian pathology.

SV2B defines a subpopulation of synaptic vesicles.

Synaptic vesicles can undergo several modes of exocytosis, endocytosis, and trafficking within individual synapses, and their fates may be linked to different vesicular protein compositions. Here, we mapped the intrasynaptic distribution of the synaptic vesicle proteins SV2B and SV2A in glutamatergic synapses of the hippocampus using three-dimensional electron microscopy. SV2B was almost completely absent from docked vesicles and a distinct cluster of vesicles found near the active zone. In contrast, SV2A was found in all domains of the synapse and was slightly enriched near the active zone. SV2B and SV2A were found on the membrane in the peri-active zone, suggesting the recycling from both clusters of vesicles. SV2B knockout mice displayed an increased seizure induction threshold only in a model employing high-frequency stimulation. Our data show that glutamatergic synapses generate molecularly distinct populations of synaptic vesicles and are able to maintain them at steep spatial gradients. The almost complete absence of SV2B from vesicles at the active zone of wildtype mice may explain why SV2A has been found more important for vesicle release.

A facile synthesis of 1,3,4-oxadiazole-based carbamothioate molecules: Antiseizure potential, EEG evaluation and in-silico docking studies

In present work, a series of novel structural hybrids of 1,3,4-oxadiazole and carbamothioate was designed by chemical modification of 2-(4-isobutylphenyl)propanoic acid. Target compounds (7a-f) were synthesized in significant yields (84–88 %) by coupling compound (4) with different electrophiles under different reaction conditions. The structures of oxadiazole based carbamothionate derivatives were confirmed by spectroscopic (FTIR, 1H NMR, 13C NMR) and physiochemical methods. During in-vivo experimentation, all synthesized compounds were tested through 6 Hz (32 mA) and PTZ (80 mg/kg) mouse seizure models. The 7b and 7c showed significant outcomes (P < 0.05) in terms of seizure severity, protection and mortality. The behavioural outcomes of PTZ tests were further strengthened with video-electroencephalogram (vEEG) findings in which EEGs were analyzed for epileptic spikes to understand the impact of 7b and 7c treatment on these ictal activities. The 7b was found most efficient in reducing the seizure spiking activity in brains of PTZ-treated mice while both 7b and 7c significantly reduced overall PTZ-induced seizure severity. The molecular docking studies also predicted the BBB permeability, reduced binding energies and good compound interaction with GABAA receptors and SV2A protein. Therefore, the observed pharmacological outcomes might be attributed to the GABAA agonistic and SV2A modulating potential of these oxadiazole-carbamothioate hybrid compounds.

Widespread cell stress and mitochondrial dysfunction occur in patients with early Alzheimer's disease.

Cell stress and impaired oxidative phosphorylation are central to mechanisms of synaptic loss and neurodegeneration in the cellular pathology of Alzheimer's disease (AD). In this study, we quantified the in vivo expression of the endoplasmic reticulum stress marker, sigma 1 receptor (S1R), using [11C]SA4503 positron emission tomography (PET), the mitochondrial complex I (MC1) with [18F]BCPP-EF, and the presynaptic vesicular protein SV2A with [11C]UCB-J in 12 patients with early AD and in 16 cognitively normal controls. We integrated these molecular measures with assessments of regional brain volumes and cerebral blood flow (CBF) measured with magnetic resonance imaging arterial spin labeling. Eight patients with AD were followed longitudinally to estimate the rate of change of the physiological and structural pathology markers with disease progression. The patients showed widespread increases in S1R (≤ 27%) and regional reduction in MC1 (≥ -28%) and SV2A (≥ -25%) radioligand binding, brain volume (≥ -23%), and CBF (≥ -26%). [18F]BCPP-EF PET MC1 binding (≥ -12%) and brain volumes (≥ -5%) showed progressive reductions over 12 to 18 months, suggesting that they both could be used as pharmacodynamic indicators in early-stage therapeutics trials. Associations of reduced MC1 and SV2A and increased S1R radioligand binding with reduced cognitive performance in AD, although exploratory, suggested a loss of metabolic functional reserve with disease. Our study thus provides in vivo evidence for widespread, clinically relevant cellular stress and bioenergetic abnormalities in early AD.

Differential effects of levetiracetam on hippocampal CA1 synaptic plasticity and molecular changes in the dentate gyrus in epileptic rats

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsies. Pharmacological treatment with anti-seizure drugs (ASDs) remains the mainstay in epilepsy management. Levetiracetam (LEV) is a second-generation ASD with a novel SV2A protein target and is indicated for treating focal epilepsies. While there is considerable literature in acute models, its effect in chronic epilepsy is less clear. Particularly, its effects on neuronal excitability, synaptic plasticity, adult hippocampal neurogenesis, and histological changes in chronic epilepsy have not been evaluated thus far, which formed the basis of the present study. Six weeks post-lithium-pilocarpine-induced status epilepticus (SE), epileptic rats were injected with levetiracetam (54 mg/kg b.w. i.p.) once daily for two weeks. Following LEV treatment, Schaffer collateral - CA1 (CA3-CA1) synaptic plasticity and structural changes in hippocampal subregions CA3 and CA1 were evaluated. The number of doublecortin (DCX+) and reelin (RLN+) positive neurons was estimated. Further, mossy fiber sprouting was evaluated in DG by Timm staining, and splash test was performed to assess the anxiety-like behavior. Chronic epilepsy resulted in decreased basal synaptic transmission and increased paired-pulse facilitation without affecting post-tetanic potentiation and long-term potentiation. Moreover, chronic epilepsy decreased hippocampal subfields volume, adult hippocampal neurogenesis, and increased reelin expression and mossy fiber sprouting with increased anxiety-like behavior. LEV treatment restored basal synaptic transmission and paired-pulse facilitation ratio in CA3-CA1 synapses. LEV also restored the CA1 subfield volume in chronic epilepsy. LEV did not affect epilepsy-induced abnormal adult hippocampal neurogenesis, ectopic migration of newborn granule cells, mossy fiber sprouting in DG, and anxiety-like behavior. Our results indicate that in addition to reducing seizures, LEV has favorable effects on synaptic transmission and structural plasticity in chronic epilepsy. These findings add new dimensions to the use of LEV in chronic epilepsy and paves way for further research into its effects on cognition and affective behavior.

Targeting hippocampal amyloidogenesis with SV2A protein modulator levetiracetam

Cerebral amyloid β (Aβ) proteostasis is compromised under neuronal overexcitation, long-term neuroinflammation and brain aging. Using the animal model of LPS-induced neuroinflammation we demonstrated that treatment with levetiracetam, a specific modulator of synaptic vesicle glycoprotein SV2A, rescues abnormal synaptic vesicle (SV) fusion and neurotransmitter release, decreasing elevated hippocampal APP levels in vivo. Therapy with levetiracetam upregulates the SV2A in hippocampus and restores the level of apolipoprotein E, involved in brain Aβ aggregation/clearance and resolution of inflammation.We demonstrated that oligomers of Aβ1-42 and Aβ1-40 peptides promote SV clustering, which reduces the rate and plateau level of subsequent homo- and heterotypic SNARE-mediated SV fusion. Oligomeric Aβ1-42 lowered ΔpH gradient across the vesicular membrane, thus affecting their neurotransmitter storage capacity. In contrast, monomers of Aβ1-42 and Aβ1-40 had negligible impact on studied processes.Our data suggests that in the course of progression of neuroinflammation oligomeric forms of Aβ1-42 and Aβ1-40 can compromise the SV fusion machinery and that antiepileptic agent levetiracetam, acting on SV recycling and restricting overexcitation, is able to affect APP processing and Aβ generation within the hippocampus in vivo.

Validation of SV2A-Targeted PET Imaging for Noninvasive Assessment of Neuroendocrine Differentiation in Prostate Cancer.

Neuroendocrine prostate cancer (NEPC) is an aggressive and lethal variant of prostate cancer (PCa), and it remains a diagnostic challenge. Herein we report our findings of using synaptic vesicle glycoprotein 2 isoform A (SV2A) as a promising marker for positron emission tomography (PET) imaging of neuroendocrine differentiation (NED). The bioinformatic analyses revealed an amplified SV2A gene expression in clinical samples of NEPC versus castration-resistant PCa with adenocarcinoma characteristics (CRPC-Adeno). Importantly, significantly upregulated SV2A protein levels were found in both NEPC cell lines and tumor tissues. PET imaging studies were carried out in NEPC xenograft models with 18F-SynVesT-1. Although 18F-SynVesT-1 is not a cancer imaging agent, it showed a significant uptake level in the SV2A+ tumor (NCI-H660: 0.70 ± 0.14 %ID/g at 50–60 min p.i.). The SV2A blockade resulted in a significant reduction of tumor uptake (0.25 ± 0.03 %ID/g, p = 0.025), indicating the desired SV2A imaging specificity. Moreover, the comparative PET imaging study showed that the DU145 tumors could be clearly visualized by 18F-SynVesT-1 but not 68Ga-PSMA-11 nor 68Ga-DOTATATE, further validating the role of SV2A-targeted imaging for noninvasive assessment of NED in PCa. In conclusion, we demonstrated that SV2A, highly expressed in NEPC, can serve as a promising target for noninvasive imaging evaluation of NED.

Selected Molecular Targets for Antiepileptogenesis.

The term epileptogenesis defines the usually durable process of converting normal brain into an epileptic one. The resistance of a significant proportion of patients with epilepsy to the available pharmacotherapy prompted the concept of a causative treatment option consisting in stopping or modifying the progress of epileptogenesis. Most antiepileptic drugs possess only a weak or no antiepileptogenic potential at all, but a few of them appear promising in this regard; these include, for example, eslicarbazepine (a sodium and T-type channel blocker), lamotrigine (a sodium channel blocker and glutamate antagonist) or levetiracetam (a ligand of synaptic vehicle protein SV2A). Among the approved non-antiepileptic drugs, antiepileptogenic potential seems to reside in losartan (a blocker of angiotensin II type 1 receptors), biperiden (an antiparkinsonian drug), nonsteroidal anti-inflammatory drugs, antioxidative drugs and minocycline (a second-generation tetracycline with anti-inflammatory and antioxidant properties). Among other possible antiepileptogenic compounds, antisense nucleotides have been considered, among these an antagomir targeting microRNA-134. The drugs and agents mentioned above have been evaluated in post-status epilepticus models of epileptogenesis, so their preventive efficacy must be verified. Limited clinical data indicate that biperiden in patients with brain injuries is well-tolerated and seems to reduce the incidence of post-traumatic epilepsy. Exceptionally, in this regard, our own original data presented here point to c-Fos as an early seizure duration, but not seizure intensity-related, marker of early epileptogenesis. Further research of reliable markers of early epileptogenesis is definitely needed to improve the process of designing adequate antiepileptogenic therapies.

LPC-DHA/EPA-Enriched Diets Increase Brain DHA and Modulate Behavior in Mice That Express Human APOE4.

Compared with APOE3, APOE4 is associated with greater age-related cognitive decline and higher risk of neurodegenerative disorders. Therefore, development of supplements that target APOE genotype-modulated processes could provide a great benefit for the aging population. Evidence suggests a link between APOE genotype and docosahexaenoic acid (DHA); however, clinical studies with current DHA supplements have produced negative results in dementia. The lack of beneficial effects with current DHA supplements may be related to limited bioavailability, as the optimal form of DHA for brain uptake is lysophosphatidylcholine (LPC)-DHA. We previously developed a method to enrich the LPC-DHA content of krill oil through lipase treatment (LT-krill oil), which resulted in fivefold higher enrichment in brain DHA levels in wild-type mice compared with untreated krill oil. Here, we evaluated the effect of a control diet, diet containing krill oil, or a diet containing LT-krill oil in APOE3- and APOE4-targeted replacement mice (APOE-TR mice; treated from 4 to 12 months of age). We found that DHA levels in the plasma and hippocampus are lower in APOE4-TR mice and that LT-krill oil increased DHA levels in the plasma and hippocampus of both APOE3- and APOE4-TR mice. In APOE4-TR mice, LT-krill oil treatment resulted in higher levels of the synaptic vesicle protein SV2A and improved performance on the novel object recognition test. In conclusion, our data demonstrate that LPC-DHA/EPA-enriched krill oil can increase brain DHA and improve memory-relevant behavior in mice that express APOE4. Therefore, long-term use of LT-krill oil supplements may on some level protect against age-related neurodegeneration.

Coordinated bi-directional trafficking of synaptic vesicle and active zone proteins in peripheral nerves

Synaptic transmission is mediated by neurotransmitters that are stored in synaptic vesicles (SV) and released at the synaptic active zone (AZ). While in recent years major progress has been made in unraveling the molecular machinery responsible for SV docking, fusion and exocytosis, the mechanisms governing AZ protein and SV trafficking through axons still remain unclear. Here, we performed stop-flow nerve ligation to examine axonal trafficking of endogenous AZ and SV proteins. Rat sciatic nerves were collected 1 h, 3 h and 8 h post ligation and processed for immunohistochemistry and electron microscopy. First, we followed the transport of an integral synaptic vesicle protein, SV2A and a SV-associated protein involved in SV trafficking, Rab3a, and observed that while SV2A accumulated on both sides of ligation, Rab3a was only noticeable in the proximal segment of the ligated nerve indicating that only SV trans-membrane protein SV2A displayed a bi-directional axonal transport. We then demonstrate that multiple AZ proteins accumulate rapidly on either side of the ligation with a timescale similar to that of SV2A. Overall, our data uncovers an unexpected robust bi-directional, coordinated -trafficking of SV and AZ proteins in peripheral nerves. This implies that pathological disruption of axonal trafficking will not only impair trafficking of newly synthesized proteins to the synapse but will also affect retrograde transport, leading to neuronal dysfunction and likely neurodegeneration.

Levetiracetam treatment leads to functional recovery after thoracic or cervical injuries of the spinal cord

Spinal cord injury (SCI) leads to dramatic impairments of motor, sensory, and autonomic functions of affected individuals. Following the primary injury, there is an increased release of glutamate that leads to excitotoxicity and further neuronal death. Therefore, modulating glutamate excitotoxicity seems to be a promising target to promote neuroprotection during the acute phase of the injury. In this study, we evaluated the therapeutic effect of a FDA approved antiepileptic drug (levetiracetam-LEV), known for binding to the synaptic vesicle protein SV2A in the brain and spinal cord. LEV therapy was tested in two models of SCI—one affecting the cervical and other the thoracic level of the spinal cord. The treatment was effective on both SCI models. Treated animals presented significant improvements on gross and fine motor functions. The histological assessment revealed a significant decrease of cavity size, as well as higher neuronal and oligodendrocyte survival on treated animals. Molecular analysis revealed that LEV acts by stabilizing the astrocytes allowing an effective uptake of the excess glutamate from the extracellular space. Overall, our results demonstrate that Levetiracetam may be a promising drug for acute management of SCI.

PET imaging reveals early and progressive dopaminergic deficits after intra-striatal injection of preformed alpha-synuclein fibrils in rats

Alpha-synuclein (a-syn) can aggregate and form toxic oligomers and insoluble fibrils which are the main component of Lewy bodies. Intra-neuronal Lewy bodies are a major pathological characteristic of Parkinson's disease (PD). These fibrillar structures can act as seeds and accelerate the aggregation of monomeric a-syn. Indeed, recent studies show that injection of preformed a-syn fibrils (PFF) into the rodent brain can induce aggregation of the endogenous monomeric a-syn resulting in neuronal dysfunction and eventual cell death.We injected 8 μg of murine a-syn PFF, or soluble monomeric a-syn into the right striatum of rats. The animals were monitored behaviourally using the cylinder test, which measures paw asymmetry, and the corridor task that measures lateralized sensorimotor response to sugar treats. In vivo PET imaging was performed after 6, 13 and 22 weeks using [11C]DTBZ, a marker of the vesicular monoamine 2 transporter (VMAT2), and after 15 and 22 weeks using [11C]UCB-J, a marker of synaptic SV2A protein in nerve terminals. Histology was performed at the three time points using antibodies against dopaminergic markers, aggregated a-syn, and MHCII to evaluate the immune response.While the a-syn PFF injection caused only mild behavioural changes, [11C]DTBZ PET showed a significant and progressive decrease of VMAT2 binding in the ipsilateral striatum. This was accompanied by a small progressive decrease in [11C]UCB-J binding in the same area. In addition, our histological analysis revealed a gradual spread of misfolded a-syn pathology in areas anatomically connected to striatum that became bilateral with time. The striatal a-syn PFF injection resulted in a progressive unilateral degeneration of dopamine terminals, and an early and sustained presence of MHCII positive ramified microglia in the ipsilateral striatum and substantia nigra.Our study shows that striatal injections of a-syn fibrils induce progressive pathological synaptic dysfunction prior to cell death that can be detected in vivo with PET. We confirm that intrastriatal injection of a-syn PFFs provides a model of progressive a-syn pathology with loss of dopaminergic and synaptic function accompanied by neuroinflammation, as found in human PD.

Levetiracetam treatment ameliorates LRRK2 pathological mutant phenotype.

Mutations in leucine‐rich repeat kinase 2 (LRRK2) are the most common genetic cause of Parkinson's disease (PD). The LRRK2 physiological and pathological function is still debated. However, different experimental evidence based on LRRK2 cellular localization and LRRK2 protein interactors suggests that LRRK2 may be part and regulate a protein network modulating vesicle dynamics/trafficking. Interestingly, the synaptic vesicle protein SV2A is part of this protein complex. Importantly, SV2A is the binding site of the levetiracetam (LEV), a compound largely used in human therapy for epilepsy treatment. The binding of LEV to SV2A reduces the neuronal firing by the modulation of vesicle trafficking although by an unclear molecular mechanism. In this short communication, we have analysed the interaction between the LRRK2 and SV2A pathways by LEV treatment. Interestingly, LEV significantly counteracts the effect of LRRK2 G2019S pathological mutant expression in three different cellular experimental models. Our data strongly suggest that LEV treatment may have a neuroprotective effect on LRRK2 pathological mutant toxicity and that LEV repositioning could be a viable compound for PD treatment.

Levetiracetam – a drug that can be used not only in the treatment of epilepsy

Levetiracetam, which belongs to the new generation of antiepileptic drugs, has a unique and not well-known mechanism of action. The drug affects the release of neurotransmitters through the binding to the synaptic vesicle protein SV2A. Moreover, it acts on calcium channels, inhibits glutamatergic neurotransmission and affects GABA-ergic neurotransmission through e.g. the Zn²⁺-induced suppression of GABAA-mediated presynaptic inhibition and the modulation of the action of GABAA antagonists. Levetiracetam has also neuroprotective activity which is associated with the influence on transcription processes, neurotransmission, antioxidant and anti-inflammatory activity. The results of recent research indicate that this complex action creates the prospect of using it in the alleviation of epileptogenesis, poststroke seizuires, seizure prophylaxis in brain injured patients and diabetic neuropathy. Furthermore, the drug may also have a beneficial effect in the treatment of Alzheimer patients with epileptic seizures and levodopa-induced dyskinesias in Parkinson’s disease.

Protective Role of Levetiracetam Against Cognitive Impairment And Brain White Matter Damage in Mouse prolonged Cerebral Hypoperfusion

White matter lesions due to cerebral hypoperfusion may be an important pathophysiology in vascular dementia and stroke, although the inherent mechanisms remain to be fully elucidated. The present study, using a mouse model of chronic cerebral hypoperfusion, examined the white matter protective effects of levetiracetam, an anticonvulsant, via the signaling cascade from the activation of cAMP-responsive element binding protein (CREB) phosphorylation. Mice underwent bilateral common carotid artery stenosis (BCAS), and were separated into the levetiracetam group (injected once only after BCAS [LEV1] or injected on three consecutive days [LEV3]), the vehicle group, or the anti-epileptic drugs with different action mechanisms phenytoin group (PHT3; injected on three consecutive days with the same condition as in LEV3). Cerebral blood flow analysis, Y-maze spontaneous alternation test, novel object recognition test, immunohistochemical and Western blot analyses, and protein kinase A assay were performed after BCAS. In the LEV3 group, SV2A expression was markedly increased, which preserved learning and memory after BCAS. Moreover, as the protein kinase A level was significantly increased, pCREB expression was also increased. The activation of microglia and astrocytes was markedly suppressed, although the number of oligodendrocyte precursor cells (OPCs) and GST-pi–positive-oligodendrocytes was markedly higher in the cerebral white matter. Moreover, oxidative stress was significantly reduced. We found that 3-day treatment with levetiracetam maintained SV2A protein expression via interaction with astrocytes, which influenced the OPC lineage through activation of CREB to protect white matter from ischemia.

Preparation of 99mTc-levetiracetam intranasal microemulsion as the first radiotracer for SPECT imaging of the Synaptic Vesicle Protein SV2A

Selective receptors imaging using gamma emitting radiopharmaceuticals allows accurate diagnosis and follow up of many brain related disorders. Levetiracetam, a selective SV2A receptor antiepileptic, was successfully radiolabeled using 99mTc. Different conditions affecting the labelling process were studied and optimum radiochemical yield of 89.8% was obtained. 99mTc-levetiracetam was effectively formulated and characterized as microemulsion with particle size of 16.34 ± 5.58 nm and polydispersity index of 0.382 ± 0.05. Parallel biodistribution studies were performed comparing brain targeting efficiency of I.V 99mTc-levetiracetam solution, I.N 99mTc-levetiracetam solution and I.N 99mTc-levetiracetam microemulsion. Brain radioactivity uptake and brain/blood uptake ratio for I.N 99mTc-levetiracetam microemulsion were higher than the other two routes at all time intervals. Such results present intranasal 99mTc-levetiracetam microemulsion as the first SPECT tracer for imaging SV2A receptor.

Syndesi launches as spin-off from UCB

Syndesi Therapeutics has launched with about $21 million in funding from investors including UCB and Johnson & Johnson. Based at J&J’s JLINX incubator in Beerse, Belgium, Syndesi will develop small molecules licensed from UCB that modulate the synaptic vesicle protein SV2A. UCB markets the SV2A modulator levetiracetam as an epilepsy treatment. The compounds that went to Syndesi are not antiepileptic but have what Syndesi calls procognitive properties that could treat neurological disorders such as Alzheimer’s disease.

Levetiracetam Affects Differentially Presynaptic Proteins in Rat Cerebral Cortex.

Presynaptic proteins are potential therapeutic targets for epilepsy and other neurological diseases. We tested the hypothesis that chronic treatment with the SV2A ligand levetiracetam affects the expression of other presynaptic proteins. Results showed that in rat neocortex no significant difference was detected in SV2A protein levels in levetiracetam treated animals compared to controls, whereas levetiracetam post-transcriptionally decreased several vesicular proteins and increased LRRK2, without any change in mRNA levels. Analysis of SV2A interactome indicates that the presynaptic proteins regulation induced by levetiracetam reported here is mediated by this interactome, and suggests that LRRK2 plays a role in forging the pattern of effects.