C/EBPß Regulates TFAM Expression, Mitochondrial Function and Autophagy in Cellular Models of Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disorder that results from the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Since there are only symptomatic treatments available, new cellular and molecular targets involved in the onset and progression of this disease are needed to develop effective treatments. CCAAT/Enhancer Binding Protein ß (C/EBPß) transcription factor levels are altered in patients with a variety of neurodegenerative diseases, suggesting that it may be a good therapeutic target for the treatment of PD. A list of genes involved in PD that can be regulated by C/EBPß was generated by the combination of genetic and in silico data, the mitochondrial transcription factor A (TFAM) being among them. In this paper, we observed that C/EBPß overexpression increased TFAM promoter activity. However, downregulation of C/EBPß in different PD/neuroinflammation cellular models produced an increase in TFAM levels, together with other mitochondrial markers. This led us to propose an accumulation of non-functional mitochondria possibly due to the alteration of their autophagic degradation in the absence of C/EBPß. Then, we concluded that C/EBPß is not only involved in harmful processes occurring in PD, such as inflammation, but is also implicated in mitochondrial function and autophagy in PD-like conditions.

Insights into the Pharmacokinetics and In Vitro Cell-Based Studies of the Imidazoline I2 Receptor Ligand B06.

The impact of neurodegenerative diseases (ND) is becoming unbearable for humankind due to their vast prevalence and the lack of efficacious treatments. In this scenario, we focused on imidazoline I2 receptors (I2-IR) that are widely distributed in the brain and are altered in patients with brain disorders. We took the challenge of modulating I2-IR by developing structurally new molecules, in particular, a family of bicyclic α-iminophosphonates, endowed with high affinity and selectivity to these receptors. Treatment of two murine models, one for age-related cognitive decline and the other for Alzheimer's disease (AD), with representative compound B06 ameliorated their cognitive impairment and improved their behavioural condition. Furthermore, B06 revealed beneficial in vitro ADME-Tox properties. The pharmacokinetics (PK) and metabolic profile are reported to de-risk B06 for progressing in the preclinical development. To further characterize the pharmacological properties of B06, we assessed its neuroprotective properties and beneficial effect in an in vitro model of Parkinson's disease (PD). B06 rescued the human dopaminergic cell line SH-SY5Y from death after treatment with 6-hydroxydopamine (6-OHDA) and showed a crucial anti-inflammatory effect in a cellular model of neuroinflammation. This research reveals B06 as a putative candidate for advancing in the difficult path of drug discovery and supports the modulation of I2-IR as a fresh approach for the therapy of ND.

New flavonoid - N,N-dibenzyl(N-methyl)amine hybrids: Multi-target-directed agents for Alzheimer´s disease endowed with neurogenic properties.

The design of multi-target directed ligands (MTDLs) is a valid approach for obtaining effective drugs for complex pathologies. MTDLs that combine neuro-repair properties and block the first steps of neurotoxic cascades could be the so long wanted remedies to treat neurodegenerative diseases (NDs). By linking two privileged scaffolds with well-known activities in ND-targets, the flavonoid and the N,N-dibenzyl(N-methyl)amine (DBMA) fragments, new CNS-permeable flavonoid - DBMA hybrids (1-13) were obtained. They were subjected to biological evaluation in a battery of targets involved in Alzheimer's disease (AD) and other NDs, namely human cholinesterases (hAChE/hBuChE), ß-secretase (hBACE-1), monoamine oxidases (hMAO-A/B), lipoxygenase-5 (hLOX-5) and sigma receptors (σ1R/σ2R). After a funnel-type screening, 6,7-dimethoxychromone - DBMA (6) was highlighted due to its neurogenic properties and an interesting MTD-profile in hAChE, hLOX-5, hBACE-1 and σ1R. Molecular dynamic simulations showed the most relevant drug-protein interactions of hybrid 6, which could synergistically contribute to neuronal regeneration and block neurodegeneration.

Novel Approaches for the Treatment of Alzheimer's and Parkinson's Disease.

Neurodegenerative disorders affect around one billion people worldwide. They can arise from a combination of genomic, epigenomic, metabolic, and environmental factors. Aging is the leading risk factor for most chronic illnesses of old age, including Alzheimer's and Parkinson's diseases. A progressive neurodegenerative process and neuroinflammation occur, and no current therapies can prevent, slow, or halt disease progression. To date, no novel disease-modifying therapies have been shown to provide significant benefit for patients who suffer from these devastating disorders. Therefore, early diagnosis and the discovery of new targets and novel therapies are of upmost importance. Neurodegenerative diseases, like in other age-related disorders, the progression of pathology begins many years before the onset of symptoms. Many efforts in this field have led to the conclusion that exits some similar events among these diseases that can explain why the aging brain is so vulnerable to suffer neurodegenerative diseases. This article reviews the current knowledge about these diseases by summarizing the most common features of major neurodegenerative disorders, their causes and consequences, and the proposed novel therapeutic approaches.

Phosphodiesterase7 Inhibition Activates Adult Neurogenesis in Hippocampus and Subventricular Zone In Vitro and In Vivo.

The phosphodiesterase 7 (PDE7) enzyme is one of the enzymes responsible for controlling intracellular levels of cyclic adenosine 3',5'-monophosphate in the immune and central nervous system. We have previously shown that inhibitors of this enzyme are potent neuroprotective and anti-inflammatory agents. In addition, we also demonstrated that PDE7 inhibition induces endogenous neuroregenerative processes toward a dopaminergic phenotype. Here, we show that PDE7 inhibition controls stem cell expansion in the subgranular zone of the dentate gyrus of the hippocampus (SGZ) and the subventricular zone (SVZ) in the adult rat brain. Neurospheres cultures obtained from SGZ and SVZ of adult rats treated with PDE7 inhibitors presented an increased proliferation and neuronal differentiation compared to control cultures. PDE7 inhibitors treatment of neurospheres cultures also resulted in an increase of the levels of phosphorylated cAMP response element binding protein, suggesting that their effects were indeed mediated through the activation of the cAMP/PKA signaling pathway. In addition, adult rats orally treated with S14, a specific inhibitor of PDE7, presented elevated numbers of proliferating progenitor cells, and migrating precursors in the SGZ and the SVZ. Moreover, long-term treatment with this PDE7 inhibitor shows a significant increase in newly generated neurons in the olfactory bulb and the hippocampus. Also a better performance in memory tests was observed in S14 treated rats, suggesting a functional relevance for the S14-induced increase in SGZ neurogenesis. Taken together, our results indicate for the first time that inhibition of PDE7 directly regulates proliferation, migration and differentiation of neural stem cells, improving spatial learning and memory tasks. Stem Cells 2017;35:458-472.

Complement component 3 (C3) expression in the hippocampus after excitotoxic injury: role of C/EBPß.

BACKGROUND: The CCAAT/enhancer-binding protein ß (C/EBPß) is a transcription factor implicated in the control of proliferation, differentiation, and inflammatory processes mainly in adipose tissue and liver; although more recent results have revealed an important role for this transcription factor in the brain. Previous studies from our laboratory indicated that CCAAT/enhancer-binding protein ß is implicated in inflammatory process and brain injury, since mice lacking this gene were less susceptible to kainic acid-induced injury. More recently, we have shown that the complement component 3 gene (C3) is a downstream target of CCAAT/enhancer-binding protein ß and it could be a mediator of the proinflammatory effects of this transcription factor in neural cells. METHODS: Adult male Wistar rats (8-12 weeks old) were used throughout the study. C/EBPß+/+ and C/EBPß-/- mice were generated from heterozygous breeding pairs. Animals were injected or not with kainic acid, brains removed, and brain slices containing the hippocampus analyzed for the expression of both CCAAT/enhancer-binding protein ß and C3. RESULTS: In the present work, we have further extended these studies and show that CCAAT/enhancer-binding protein ß and C3 co-express in the CA1 and CA3 regions of the hippocampus after an excitotoxic injury. Studies using CCAAT/enhancer-binding protein ß knockout mice demonstrate a marked reduction in C3 expression after kainic acid injection in these animals, suggesting that indeed this protein is regulated by C/EBPß in the hippocampus in vivo. CONCLUSIONS: Altogether these results suggest that CCAAT/enhancer-binding protein ß could regulate brain disorders, in which excitotoxic and inflammatory processes are involved, at least in part through the direct regulation of C3.

CCAAT/enhancer binding protein ß directly regulates the expression of the complement component 3 gene in neural cells: implications for the pro-inflammatory effects of this transcription factor.

BACKGROUND: The CCAAT/enhancer-binding protein ß (C/EBPß) is a transcription factor, which was first identified as a regulator of differentiation and inflammatory processes mainly in adipose tissue and liver; however, its function in the brain was largely unknown for many years. Previous studies from our laboratory indicated that C/EBPß is implicated in inflammatory process and brain injury, since mice lacking this gene were less susceptible to kainic acid-induced injury. METHODS: We first performed cDNA microarrays analysis using hippocampal RNA isolated from C/EBPß (+/+) and C/EBPß (-/-) mice. Immunocytochemical and immunohistochemical studies were done to evaluate C/EBPß and C3 levels. Transient transfection experiments were made to analyze transcriptional regulation of C3 by C/EBPß. To knockdown C/EBPß and C3 expression, mouse astrocytes were infected with lentiviral particles expressing an shRNA specific for C/EBPß or an siRNA specific for C3. RESULTS: Among the genes displaying significant changes in expression was complement component 3 (C3), which showed a dramatic decrease in mRNA content in the hippocampus of C/EBPß (-/-) mice. C3 is the central component of the complement and is implicated in different brain disorders. In this work we have found that C/EBPß regulates C3 levels in rodents glial in vitro and in the rat Substantia nigra pars compacta (SNpc) in vivo following an inflammatory insult. Analysis of the mouse C3 promoter showed that it is directly regulated by C/EBPß through a C/EBPß consensus site located at position -616/-599 of the gene. In addition, we show that depletion of C/EBPß by a specific shRNA results in a significant decrease in the levels of C3 together with a reduction in the increased levels of pro-inflammatory agents elicited by lipopolysaccharide treatment. CONCLUSIONS: Altogether, these results indicate that C3 is a downstream target of C/EBPß, and it could be a mediator of the pro-inflammatory effects of this transcription factor in neural cells.

Preclinical Evaluation of an Imidazole-Linked Heterocycle for Alzheimer's Disease.

Humanity is facing a vast prevalence of neurodegenerative diseases, with Alzheimer's disease (AD) being the most dominant, without efficacious drugs, and with only a few therapeutic targets identified. In this scenario, we aim to find molecular entities that modulate imidazoline I2 receptors (I2-IRs) that have been pointed out as relevant targets in AD. In this work, we explored structural modifications of well-established I2-IR ligands, giving access to derivatives with an imidazole-linked heterocycle as a common key feature. We report the synthesis, the affinity in human I2-IRs, the brain penetration capabilities, the in silico ADMET studies, and the three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of this new bunch of I2-IR ligands. Selected compounds showed neuroprotective properties and beneficial effects in an in vitro model of Parkinson's disease, rescued the human dopaminergic cell line SH-SY5Y from death after treatment with 6-hydroxydopamine, and showed crucial anti-inflammatory effects in a cellular model of neuroinflammation. After a preliminary pharmacokinetic study, we explored the action of our representative 2-(benzo[b]thiophen-2-yl)-1H-imidazole LSL33 in a mouse model of AD (5xFAD). Oral administration of LSL33 at 2 mg/Kg for 4 weeks ameliorated 5XFAD cognitive impairment and synaptic plasticity, as well as reduced neuroinflammation markers. In summary, this new I2-IR ligand that promoted beneficial effects in a well-established AD mouse model should be considered a promising therapeutic strategy for neurodegeneration.

Changes in Liver Lipidomic Profile in G2019S-LRRK2 Mouse Model of Parkinson's Disease.

The identification of Parkinson's disease (PD) biomarkers has become a main goal for the diagnosis of this neurodegenerative disorder. PD has not only been intrinsically related to neurological problems, but also to a series of alterations in peripheral metabolism. The purpose of this study was to identify metabolic changes in the liver in mouse models of PD with the scope of finding new peripheral biomarkers for PD diagnosis. To achieve this goal, we used mass spectrometry technology to determine the complete metabolomic profile of liver and striatal tissue samples from WT mice, 6-hydroxydopamine-treated mice (idiopathic model) and mice affected by the G2019S-LRRK2 mutation in LRRK2/PARK8 gene (genetic model). This analysis revealed that the metabolism of carbohydrates, nucleotides and nucleosides was similarly altered in the liver from the two PD mouse models. However, long-chain fatty acids, phosphatidylcholine and other related lipid metabolites were only altered in hepatocytes from G2019S-LRRK2 mice. In summary, these results reveal specific differences, mainly in lipid metabolism, between idiopathic and genetic PD models in peripheral tissues and open up new possibilities to better understand the etiology of this neurological disorder.

The new iminothiadiazole derivative VP1.14 ameliorates hippocampal damage after an excitotoxic injury.

Increased levels of glutamate causing excitotoxic damage accompany many neurological disorders. A well-characterized model of excitotoxic damage involves administration of kainic acid (KA), which causes limbic seizure activity and subsequent neuronal death, particularly in the CA1 and CA3 areas of the hippocampus. Inhibition of the enzyme glycogen synthase kinase-3 (GSK-3) and cAMP levels might play an important role in neuroprotection. As intracellular cAMP levels depend, in part, on the activity of the phosphodiesterase enzymes (PDEs), these enzymes have recently emerged as potential therapeutic targets for the treatment of several diseases. In previous works, we have shown a potent anti-inflammatory and neuroprotective effect of GSK-3 inhibition in a model of excitotoxicity, as well as a reduction of nigrostriatal dopaminergic neuronal cell death after phosphodiesterase 7 inhibition, which leads to an increase in cAMP levels. This study was undertaken to determine whether simultaneous inhibition of GSK-3 and PDE-7 by a novel 5-imino-1,2,4-thiadiazole compound, named VP1.14, could prevent the massive neuronal loss in the hippocampus evoked by intrahippocampal injection of KA. Here, we show that rats treated with VP1.14 showed a reduced inflammatory response after KA injection, and exhibited a significant reduction in pyramidal cell loss in the CA1 and CA3 areas of the hippocampus. Studies with hippocampal HT22 cells in vitro also showed a clear neuroprotective effect of VP1.14 and an anti-inflammatory effect shown by a decrease in the nitrite liberation and in the expression of pro-inflammatory cytokines by primary cultures of astrocytes treated with lipopolysaccharide.

Neuroprotective and Anti-Inflammatory Effects of Linoleic Acid in Models of Parkinson's Disease: The Implication of Lipid Droplets and Lipophagy.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease after Alzheimer's disease. The principal pathological feature of PD is the progressive loss of dopaminergic neurons in the ventral midbrain. This pathology involves several cellular alterations: oxidative stress, mitochondrial dysfunction, loss of proteostasis, and autophagy impairment. Moreover, in recent years, lipid metabolism alterations have become relevant in PD pathogeny. The modification of lipid metabolism has become a possible way to treat the disease. Because of this, we analyzed the effect and possible mechanism of action of linoleic acid (LA) on an SH-SY5Y PD cell line model and a PD mouse model, both induced by 6-hydroxydopamine (6-OHDA) treatment. The results show that LA acts as a potent neuroprotective and anti-inflammatory agent in these PD models. We also observed that LA stimulates the biogenesis of lipid droplets and improves the autophagy/lipophagy flux, which resulted in an antioxidant effect in the in vitro PD model. In summary, we confirmed the neuroprotective effect of LA in vitro and in vivo against PD. We also obtained some clues about the novel neuroprotective mechanism of LA against PD through the regulation of lipid droplet dynamics.

Seroprevalence of anti-SARS-CoV-2 IgG antibodies: relationship with COVID-19 diagnosis, symptoms, smoking, and method of transmission.

Aims: The study of SARS-CoV-2 antibodies in the population is a crucial step towards overcoming the COVID-19 pandemic. Seroepidemiological studies allow an estimation of the number of people who have been exposed to the virus, as well as the number of people who are still susceptible to infection. Methods: In total, 13 560 people from Arganda del Rey, Madrid (Spain) were assessed between January and March 2021 for the presence of IgG antibodies, using rapid tests and histories of symptoms compatible with COVID-19. Results: 24.2% of the participants had IgG antibodies and 9% had a positive COVID-19 diagnosis. Loss of smell/taste was the most discriminating symptom of the disease. The main transmitters of infection were found to be household members. Unexpectedly, in smokers, the incidence of positive COVID-19 diagnoses was significantly lower. Additionally, it was found that there was a discrepancy between COVID-19 diagnosis and the presence of IgG antibodies. Conclusions: Rapid anti-IgG tests are less reliable in detecting SARS-CoV-2 infection at an individual level, but are functional in estimating SARS-CoV-2 infection rates at an epidemiological level. The loss of smell/taste is a potential indicator for establishing COVID-19 infection.

Resveratrol-Based MTDLs to Stimulate Defensive and Regenerative Pathways and Block Early Events in Neurodegenerative Cascades.

By replacing a phenolic ring of (E)-resveratrol with an 1,3,4-oxadiazol-2(3H)-one heterocycle, new resveratrol-based multitarget-directed ligands (MTDLs) were obtained. They were evaluated in several assays related to oxidative stress and inflammation (monoamine oxidases, nuclear erythroid 2-related factor, quinone reductase-2, and oxygen radical trapping) and then in experiments of increasing complexity (neurogenic properties and neuroprotection vs okadaic acid). 5-[(E)-2-(4-Methoxyphenyl)ethenyl]-3-(prop-2-yn-1-yl)-1,3,4-oxadiazol-2(3H)-one (4e) showed a well-balanced MTDL profile: cellular activation of the NRF2-ARE pathway (CD = 9.83 µM), selective inhibition of both hMAO-B and QR2 (IC50s = 8.05 and 0.57 µM), and the best ability to promote hippocampal neurogenesis. It showed a good drug-like profile (positive in vitro central nervous system permeability, good physiological solubility, no glutathione conjugation, and lack of PAINS or Lipinski alerts) and exerted neuroprotective and antioxidant actions in both acute and chronic Alzheimer models using hippocampal tissues. Thus, 4e is an interesting MTDL that could stimulate defensive and regenerative pathways and block early events in neurodegenerative cascades.

Peroxisome proliferator-activated receptor γ ligands regulate neural stem cell proliferation and differentiation in vitro and in vivo.

Peroxisome proliferator-activated receptor gamma (PPARγ) belongs to a family of ligand-activated nuclear receptors and its ligands are known to control many physiological and pathological situations. Its role in the central nervous system has been under intense analysis during the last years. Here we show a novel function for PPARγ in controlling stem cell expansion in the adult mammalian brain. Adult rats treated with pioglitazone, a specific ligand of PPARγ, had elevated numbers of proliferating progenitor cells in the subventricular zone and the rostral migratory stream. Electron microscopy analysis also showed important changes in the subventricular zone ultrastructure of pioglitazone-treated animals including an increased number of migratory cell chains. These results were further confirmed in vitro. Neurosphere assays revealed significant increases in the number of neurosphere forming cells from pioglitazone- and rosiglitazone (two specific ligands of PPARγ receptor)-treated cultures that exhibited enhanced capacity for cell migration and differentiation. The effects of pioglitazone were blocked by the PPARγ receptor antagonists GW9662 and T0070907, suggesting that its effects are mediated by a mechanism dependent on PPARγ activation. These results indicate for the first time that activation of PPARγ receptor directly regulates proliferation, differentiation, and migration of neural stem cells in vivo.

Phosphodiesterase 7 Regulation in Cellular and Rodent Models of Parkinson's Disease.

Parkinson's disease is characterized by a loss of dopaminergic neurons in the ventral midbrain. This disease is diagnosed when around 50% of these neurons have already died; consequently, therapeutic treatments start too late. Therefore, an urgent need exists to find new targets involved in the onset and progression of the disease. Phosphodiesterase 7 (PDE7) is a key enzyme involved in the degradation of intracellular levels of cyclic adenosine 3', 5'-monophosphate in different cell types; however, little is known regarding its role in neurodegenerative diseases, and specifically in Parkinson's disease. We have previously shown that chemical as well as genetic inhibition of this enzyme results in neuroprotection and anti-inflammatory activity in different models of neurodegenerative disorders, including Parkinson's disease. Here, we have used in vitro and in vivo models of Parkinson's disease to study the regulation of PDE7 protein levels. Our results show that PDE7 is upregulated after an injury both in the human dopaminergic cell line SH-SY5Y and in primary rat mesencephalic cultures and after lipopolysaccharide or 6-hidroxydopamine injection in the Substantia nigra pars compacta of adult mice. PDE7 increase takes place mainly in degenerating dopaminergic neurons and in microglia cells. This enhanced expression appears to be direct since 6-hydroxydopamine and lipopolysaccharide increase the expression of a 962-bp fragment of its promoter. Taking together, these results reveal an essential function for PDE7 in the pathways leading to neurodegeneration and inflammatory-mediated brain damage and suggest novel roles for PDE7 in neurodegenerative diseases, specifically in PD, opening the door for new therapeutic interventions.

N,N-dimethyltryptamine compound found in the hallucinogenic tea ayahuasca, regulates adult neurogenesis in vitro and in vivo.

N,N-dimethyltryptamine (DMT) is a component of the ayahuasca brew traditionally used for ritual and therapeutic purposes across several South American countries. Here, we have examined, in vitro and vivo, the potential neurogenic effect of DMT. Our results demonstrate that DMT administration activates the main adult neurogenic niche, the subgranular zone of the dentate gyrus of the hippocampus, promoting newly generated neurons in the granular zone. Moreover, these mice performed better, compared to control non-treated animals, in memory tests, which suggest a functional relevance for the DMT-induced new production of neurons in the hippocampus. Interestingly, the neurogenic effect of DMT appears to involve signaling via sigma-1 receptor (S1R) activation since S1R antagonist blocked the neurogenic effect. Taken together, our results demonstrate that DMT treatment activates the subgranular neurogenic niche regulating the proliferation of neural stem cells, the migration of neuroblasts, and promoting the generation of new neurons in the hippocampus, therefore enhancing adult neurogenesis and improving spatial learning and memory tasks.

Metabolic alterations in plasma from patients with familial and idiopathic Parkinson's disease.

The research of new biomarkers for Parkinson's disease is essential for accurate and precocious diagnosis, as well as for the discovery of new potential disease mechanisms and drug targets. The main objective of this work was to identify metabolic changes that might serve as biomarkers for the diagnosis of this neurodegenerative disorder. For this, we profiled the plasma metabolome from mice with neurotoxin-induced Parkinson's disease as well as from patients with familial or sporadic Parkinson's disease. By using mass spectrometry technology, we analyzed the complete metabolome from healthy volunteers compared to patients with idiopathic or familial (carrying the G2019S or R1441G mutations in the LRRK2 gene) Parkinson's disease, as well as, from mice treated with 6-hydroxydopamine to induce Parkinson disease. Both human and murine Parkinson was accompanied by an increase in plasma levels of unconjugated bile acids (cholic acid, deoxycholic acid and lithocholic acid) and purine base intermediary metabolites, in particular hypoxanthine. The comprehensive metabolomic analysis of plasma from Parkinsonian patients underscores the importance of bile acids and purine metabolism in the pathophysiology of this disease. Therefore, plasma measurements of certain metabolites related to these pathways might contribute to the diagnosis of Parkinson's Disease.

Tuning melatonin receptor subtype selectivity in oxadiazolone-based analogues: Discovery of QR2 ligands and NRF2 activators with neurogenic properties.

New multi-target indole and naphthalene derivatives containing the oxadiazolone scaffold as a bioisostere of the melatonin acetamido group have been developed. The novel compounds were characterized at melatonin receptors MT1R and MT2R, quinone reductase 2 (QR2), lipoxygenase-5 (LOX-5), and monoamine oxidases (MAO-A and MAO-B), and also as radical scavengers. We found that selectivity within the oxadiazolone series can be modulated by modifying the side chain functionality and co-planarity with the indole or naphthalene ring. In phenotypic assays, several oxadiazolone-based derivatives induced signalling mediated by the transcription factor NRF2 and promoted the maturation of neural stem-cells into a neuronal phenotype. Activation of NRF2 could be due to the binding of indole derivatives to KEAP1, as deduced from surface plasmon resonance (SPR) experiments. Molecular modelling studies using the crystal structures of QR2 and the KEAP1 Kelch-domain, as well as the recently described X-ray free-electron laser (XFEL) structures of chimeric MT1R and MT2R, provided a rationale for the experimental data and afforded valuable insights for future drug design endeavours.

Anticonvulsant and neuroprotective effects of the novel calcium antagonist NP04634 on kainic acid-induced seizures in rats.

Kainic acid (KA)-induced status epilepticus (SE) is a well-characterized model of excitotoxic neuronal injury. Excitotoxicity results from activation of specific glutamate receptors, with resultant elevation of intracellular Ca(2+). The CA1 and CA3 subregions of the hippocampus are especially vulnerable to KA, and this pattern of neuronal injury resembles that occurring in patients with temporal lobe epilepsy. Calcium plays an essential role in excitotoxicity, and accordingly calcium channel inhibitors have been shown to have protective effects in various experimental models of epilepsy and brain injury. Moreover, they also potentiate the antiseizure efficacy of conventional antiepileptic drugs. This study was undertaken to determine whether NP04634, a novel compound, reported as a non-L-type voltage-sensitive calcium channel (VSCC) inhibitor, could prevent the entrance in SE and the neuronal loss evoked by intraperitoneal injection of KA. Our results show that intragastrical administration of NP04634 reduced the percentage of rats that entered SE after KA injection, increased the latency of SE entry, and significantly reduced the mortality of rats that entered SE. Also, NP04634 prevented the loss of hippocampal CA1 and CA3 pyramidal neurons and reduced the gliosis induced by KA. These results point to a potential anticonvulsant and neuroprotective role for NP04634.

NP031112, a thiadiazolidinone compound, prevents inflammation and neurodegeneration under excitotoxic conditions: potential therapeutic role in brain disorders.

Inflammation and neurodegeneration coexist in many acute damage and chronic CNS disorders (e.g., stroke, Alzheimer's disease, Parkinson's disease). A well characterized animal model of brain damage involves administration of kainic acid, which causes limbic seizure activity and subsequent neuronal death, especially in the CA1 and CA3 pyramidal cells and interneurons in the hilus of the hippocampus. Our previous work demonstrated a potent anti-inflammatory and neuroprotective effect of two thiadiazolidinones compounds, NP00111 (2,4-dibenzyl-[1,2,4]thiadiazolidine-3,5-dione) and NP01138 (2-ethyl-4-phenyl-[1,2,4]thiadiazolidine-3,5-dione), in primary cultures of cortical neurons, astrocytes, and microglia. Here, we show that injection of NP031112, a more potent thiadiazolidinone derivative, into the rat hippocampus dramatically reduces kainic acid-induced inflammation, as measured by edema formation using T2-weighted magnetic resonance imaging and glial activation and has a neuroprotective effect in the damaged areas of the hippocampus. Last, NP031112-induced neuroprotection, both in vitro and in vivo, was substantially attenuated by cotreatment with GW9662 (2-chloro-5-nitrobenzanilide), a known antagonist of the nuclear receptor peroxisome proliferator-activated receptor gamma, suggesting that the effects of NP031112 can be mediated through activation of this receptor. As such, these findings identify NP031112 as a potential therapeutic agent for the treatment of neurodegenerative disorders.