Role of cocaine- and amphetamine-regulated transcript in estradiol-mediated neuroprotection

Pyrroloquinoline quinone protects against murine hepatitis virus strain 3-induced fulminant hepatitis by inhibiting the Keap1/Nrf2 signaling

Fulminant hepatitis (FH) is a life-threatening clinical liver syndrome characterized by substantial hepatocyte necrosis and severe liver damage. FH is typically associated with severe oxidative stress, inflammation, and mitochondrial dysfunction. Pyrroloquinoline quinone (PQQ), a naturally occurring redox cofactor, functions as an essential nutrient and antioxidant and reportedly inhibits oxidative stress and exerts potent anti-inflammatory effects. In the present study, we aimed to evaluate the therapeutic efficacy of PQQ in murine hepatitis virus strain 3 (MHV-3)-induced FH and examined the underlying mechanism. An MHV-3-induced FH mouse model was established for in vivo examination. Liver sinusoidal endothelial cells (LSECs) were used for in vitro experiments. Herein, we observed that PQQ supplementation significantly attenuated MHV-3-induced hepatic injury by suppressing inflammatory responses and reducing oxidative stress. Mechanistically, PQQ supplementation ameliorated MHV-3-induced hepatic damage by down-regulating the Keap1/Nrf2 signaling pathway in vivo and in vitro. Furthermore, Nrf2 small interfering RNA targeting LSECs abrogated the PQQ-mediated protective effects against MHV-3-related liver injury. Our results deepen our understanding of the hepatoprotective function of PQQ against MHV-3-induced liver injury and provide evidence that alleviating oxidative stress might afford a novel therapeutic strategy for treating FH.

Cocaine and amphetamine regulated transcript (CART) mediates sex differences in binge drinking through central taste circuits

The neuropeptide cocaine- and amphetamine-regulated transcript (CART) has been implicated in alcohol consumption and reward behaviours, yet mechanisms mediating these effects have yet to be identified. Using a transgenic CART knockout (KO) mouse line we uncovered a sexually dimorphic effect of CART in binge drinking, with male CART KO mice increasing intake, whilst female CART KO mice decreased their alcohol intake compared to controls. Female CART KO mice show greater sensitivity to bitter solutions that can be overshadowed through addition of a sweetener, implicating taste as a factor. Further we identify that this is not driven through peripherally circulating sex hormones, but the central nucleus of the amygdala (CeA) is a locus where CART contributes to the regulation of alcohol consumption, with CeA CART neutralisation specifically reducing plain alcohol, but not sweetened alcohol consumption in female mice. These findings may have implications for the development of sex-specific treatment options for alcohol use disorders through targeting the CART system.

Expression and role of cocaine-amphetamine regulated transcript (CART) in the proliferation of biliary epithelium

Cholangiocytes, the epithelial cells that line the biliary tree, can proliferate under the stimulation of several factors through both autocrine and paracrine pathways. The cocaine-amphetamine-regulated-transcript (CART) peptide has several physiological functions, and it is widely expressed in several organs. CART increases the survival of hippocampal neurons by upregulating brain-derived neurotrophic factor (BDNF), whose expression has been correlated to the proliferation rate of cholangiocytes. In the present study, we aimed to evaluate the expression of CART and its role in modulating cholangiocyte proliferation in healthy and bile duct ligated (BDL) rats in vivo, as well as in cultured normal rat cholangiocytes (NRC) in vitro. Liver samples from both healthy and BDL (1 week) rats, were analyzed by immunohistochemistry and immunofluorescence for CART, CK19, TrkB and p75NTR BDNF receptors. PCNA staining was used to evaluate the proliferation of the cholangiocytes, whereas TUNEL assay was used to evaluate biliary apoptosis. NRC treated or not with CART were used to confirm the role of CART on cholangiocytes proliferation and the secretion of BDNF. Cholangiocytes proliferation, apoptosis, CART and TrkB expression were increased in BDL rats, compared to control rats. We found a higher expression of TrkB and p75NTR, which could be correlated with the proliferation rate of biliary tree during BDL. The in vitro study demonstrated increased BDNF secretion by NRC after treatment with CART compared with control cells. As previously reported, proliferating cholangiocytes acquire a neuroendocrine phenotype, modulated by several factors, including neurotrophins. Accordingly, CART may play a key role in the remodeling of biliary epithelium during cholestasis by modulating the secretion of BDNF.

Transcriptomic Analysis of Glycosylation and Neuroregulatory Pathways in Rodent Models in Response to Psychedelic Molecules

The potential for psychedelic molecules in impacting cognitive flexibility has long been supported and acknowledged across scientific reports. In the current study, an approach leveraging knowledge-based gene-set information analysis has been adopted to explore the potential impact of psychedelic molecules on both glycosylation, (a post-translational modifications (PTM)) and on neuro-regulatory pathways. Though limitations and restrictions rise from the scarcity of publicly available 'omics' data, targeted analysis enabled us to identify a number of key glycogenes (Hexb, Hs6st2, Col9a2, B3gat2, Mgat5, Bgn) involved the structural organization of extracellular matrix and neuroprotective factors (Kl, Pomc, Oxt, Gal, Avp, Cartpt) which play vital roles in neuron protection, development as well as synaptic stability. In response to psychedelic molecules, we found that these genes and associated pathways are transcriptional altered in rodent models. The approach used indicates the potential to exploit existing datasets for hypothesis generation and testing for the molecular processes which play a role in the physiological response to psychedelic molecule effects. These reported findings, which focused on alterations in glycogenes and neuro-regulatory factors may provide a novel range of biomarkers to track the beneficial, as well as potential toxicological effects of psychedelic molecules.

Emerging targets signaling for inflammation in Parkinson's disease drug discovery

Parkinson's disease (PD) patients not only show motor features such as bradykinesia, tremor, and rigidity but also non-motor features such as anxiety, depression, psychosis, memory loss, attention deficits, fatigue, sexual dysfunction, gastrointestinal issues, and pain. Many pharmacological treatments are available for PD patients; however, these treatments are partially or transiently effective since they only decrease the symptoms. As these therapies are unable to restore dopaminergic neurons and stop the development of Parkinson's disease, therefore, the need for an effective therapeutic approach is required. The current review summarizes novel targets for PD, that can be utilized to identify disease-modifying treatments.

Aqueous humor proteomic analysis of acute angle-closure glaucoma with visual field loss

Background

Acute angle-closure glaucoma (AACG) is an ophthalmic emergency that occurs over the course of hours or days and may cause irreversible blindness if not treated immediately. In most cases, optic nerve damage is the cause of visual field (VF) loss in AACG. There has been no reliable biomarker found to evaluate optic nerve damage to date. Aqueous humor (AH) proteome analysis might reveal the proteomic alterations in AACG and provide helpful clues in the search for an AH biomarker of optic nerve damage and VF loss.

Methods

In this study, we used the AH proteome to explore the functions of differentially expressed proteins (DEPs) during disease progression. The AH proteins from the early-stage group and late-stage group were extracted and analyzed by the data-independent acquisition (DIA) method. The DEPs functions were annotated, and parallel reaction monitoring (PRM) was used to validate the key DEPs.

Results

A total of 87 DEPs were found. Gene Ontology analysis showed that most DEPs were enriched in immunology, hemodynamics, and apoptosis. Ingenuity pathway analysis found that vascular endothelial growth factor (VEGF) signaling, the production of reactive oxygen species (ROS) in macrophages, and the nuclear factor erythroid 2-related factor 2 (NRF2)-mediated oxidative stress response were active pathways in the late stage of AACG. The mechanism of retinal ganglion cell (RGC) death was hypothesized on the basis of DEP functional analysis. A total of 20 DEPs were validated by using PRM, and prostaglandin-H2 D-isomerase was found to have the potential to evaluate optic nerve damage.

Conclusions

This study showed that AH proteomic analysis could reveal the proteomic alterations in the pathogenesis of VF loss in AACG and help to provide objective protein biomarkers to evaluate VF loss. These findings will benefit the application of the AH proteome to clinical research.

CART mitigates oxidative stress and DNA damage in memory deficits of APP/PS1 mice via upregulating β‑amyloid metabolism‑associated enzymes

Alzheimer's disease (AD) is the most common form of dementia that is primarily characterized by progressive cognitive deficits. The toxicity of amyloid β-protein (Aβ) serves an important role in the progression of AD, resulting in neuronal loss via a number of possible mechanisms, including oxidative stress, mitochondrial dysfunction, energy depletion, apoptosis and neuroinflammation. Previous studies have reported that cocaine amphetamine regulated transcript (CART) treatment improves memory and synaptic structure in APP/PS1 mice. Therefore, the present study aimed to investigate whether CART served a protective role against memory deficits in AD. APP/PS1 mice were treated with CART or PBS. Spatial memory was assessed using the Morris water maze. Oxidative stress and DNA damage were compared among wild-type, APP/PS1 and CART-treated APP/PS1 mice. The mRNA and protein expression levels of Aβ metabolism-associated enzymes, including neprilysin (NEP), insulin-degrading enzyme (IDE), receptor for advanced glycation end products (RAGE) and low-density lipoprotein receptor-related protein 1 (LRP-1), in the hippocampus were measured via reverse transcription-quantitative PCR and western blotting, respectively. CART improved the memory impairment of APP/PS1 mice by reducing oxidative stress, inhibiting DNA damage and protecting against mitochondrial dysfunction in the cerebral cortex and hippocampus. CART also reduced cell senescence and oxidative stress in Aβ1-42-exposed primary cortical neurons in APP/PS1 mice. Moreover, CART promoted Aβ degradation via modulating Aβ metabolism-associated enzymes, including IDE, NEP, LRP-1 and RAGE. Collectively, the present study indicated that CART improved the learning and memory capacity of APP/PS mice, thus may have potential to serve as a novel therapeutic agent for AD.

Cocaine- and amphetamine-regulated transcript protects synaptic structures in neurons after ischemic cerebral injury

Cocaine-regulated and amphetamine-regulated transcript (CART) is a neuropeptide with reported neuroprotective effects in ischemic cerebral injury. However, its mechanism has not yet been elucidated. Herein, we investigated the role and mechanism of CART in synaptic plasticity in neurons after ischemic cerebral stroke. We found that the survival rate of the oxygen-glucose deprivation (OGD) neurons was increased after CART treatment. Moreover, CART treatment significantly attenuated ischemia-induced neuronal synaptic damage and increased synaptophysin expression. In addition, the number of presynaptic vesicles was increased and the postsynaptic density (PSD) was thickened after CART treatment. Mechanistically, CART treatment enhanced the expression of Arc mRNA in a cAMP response element binding protein (CREB) dependent manner in OGD neurons, and blockade of CREB by KG-501 eliminated the protective effect of CART. Collectively, CART protected the synaptic structure in neurons after ischemic cerebral injury by increasing the Arc expression via upregulating p-CREB.

The neuroprotective effect of NeuroAid on morphine-induced amnesia with respect to the expression of TFAM, PGC-1α, ΔfosB and CART genes in the hippocampus of male Wistar rats

Morphine is a natural alkaloid which derived from the opium poppy Papaver somniferum. Many studies have reported the effect of morphine on learning, memory and gene expression. CART (cocaine-amphetamine regulated transcript)is an important neuropeptide which has a critical role in physiological processes including drug dependence and antioxidant activity. ΔfosB is a transcription factor which modulates synaptic plasticity and affects learning and memory. TFAM (the mitochondrial transcription factor A) and PGC-1α (Peroxisome proliferator-activated receptor γ coactivator-1α) are critically involved in mitochondrial biogenesis and antioxidant pathways. NeuroAid is a Chinese medicine that induces neuroprotective and anti-apoptotic effects. In this research, we aimed to investigate the effect of NeuroAid on morphine-induced amnesia with respect to the expression of TFAM, PGC-1α, ΔfosB and CART in the rat's hippocampus. In this study, Morphine sulfate (at increasing doses), Naloxone hydrochloride (2.5 mg/kg) and NeuroAid (2.5 mg/kg) were administered intraperitoneal and real-time PCR reactions were done to assess gene expression. The results showed, morphine impaired memory of step-through passive avoidance, while NeuroAid had no effect. NeuroAid attenuated (but not reversed) morphine-induced memory impairment in morphine-addicted rats. Morphine increased the expression of PGC-1α and decreased the expression of CART. However, NeuroAid increased the expression of TFAM, PGC-1α, ΔfosB and CART. NeuroAid restored the effect of morphine on the expression of CART and PGC-1α. In conclusion, morphine impaired memory of step-through passive avoidance and NeuroAid attenuated this effect. The effect of NeuroAid on morphine-induced memory impairment/gene expression may be related to its anti-apoptotic and neuroprotective effects.

Molecular mechanisms and cellular events involved in the neuroprotective actions of estradiol. Analysis of sex differences

Estradiol, either from peripheral or central origin, activates multiple molecular neuroprotective and neuroreparative responses that, being mediated by estrogen receptors or by estrogen receptor independent mechanisms, are initiated at the membrane, the cytoplasm or the cell nucleus of neural cells. Estrogen-dependent signaling regulates a variety of cellular events, such as intracellular Ca²⁺ levels, mitochondrial respiratory capacity, ATP production, mitochondrial membrane potential, autophagy and apoptosis. In turn, these molecular and cellular actions of estradiol are integrated by neurons and non-neuronal cells to generate different tissue protective responses, decreasing blood-brain barrier permeability, oxidative stress, neuroinflammation and excitotoxicity and promoting synaptic plasticity, axonal growth, neurogenesis, remyelination and neuroregeneration. Recent findings indicate that the neuroprotective and neuroreparative actions of estradiol are different in males and females and further research is necessary to fully elucidate the causes for this sex difference.

Ghrelin improves muscle function in dystrophin-deficient mdx mice by inhibiting NLRP3 inflammasome activation

AIMS

Immuno-inflammation contributes to the pathogenesis of Duchenne muscular dystrophy (DMD), characterized by progressive muscle degeneration and weakness. The nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is crucial for initiating innate immunity. Ghrelin is a circulating hormone that exerts anti-inflammatory activity in several inflammatory diseases. However, the role of ghrelin in DMD and underlying mechanism are still unstated. Therefore, we investigated the effect and potential mechanism of ghrelin on muscle morphology and muscular function of mdx mice, a mouse model of DMD.

MAIN METHODS

4-Week-old male mdx mice were injected intraperitoneally with ghrelin (100 μg/kg of body weight/day) or saline for 4 weeks. Then, muscle performance was evaluated by behavioral tests. Skeletal muscles samples were collected and relevant parameters were measured by using histopathological analysis and molecular biology techniques both in mdx muscles and primary myoblasts.

KEY FINDINGS

Ghrelin significantly improved motor performance, alleviated muscle pathology and decreased inflammatory cell infiltration in mdx mice. Importantly, ghrelin dramatically inhibited NLRP3 inflammasome activation and reduced the production of mature IL-1β both in dystrophic muscles and in lipopolysaccharide (LPS)-primed primary myoblasts induced by the NLRP3 inflammasome activator benzylated ATP (BzATP). Furthermore, the inhibition of NLRP3 inflammasome by ghrelin was partly mediated by the suppression of JAK2-STAT3 and p38 MAPK signaling pathway.

SIGNIFICANCE

Our findings reveal that ghrelin suppresses muscle inflammation and ameliorates disease phenotype through inhibition of NLRP3 inflammasome activation and the production of IL-1β in mdx mice, which suggests new therapeutic potential of ghrelin in DMD.

Cocaine- and amphetamine-regulated transcript (CART): A multifaceted neuropeptide

Over the last 35 years, the continuous discovery of novel neuropeptides has been the key to the better understanding of how the central nervous system has integrated with neuronal signals and behavioral responses. Cocaine and amphetamine-regulated transcript (CART) was discovered in 1995 in the rat striatum but later was found to be highly expressed in the hypothalamus. The widespread distribution of CART peptide in the brain complicated the understanding of the role played by this neurotransmitter. The main objective of the current compact review is to piece together the fragments of available information about origin, expression, distribution, projection, and function of CART peptides. Accumulative evidence suggests CART as a neurotransmitter and neuroprotective agent that is mainly involved in regulation of feeding, addiction, stress, anxiety, innate fear, neurological disease, neuropathic pain, depression, osteoporosis, insulin secretion, learning, memory, reproduction, vision, sleep, thirst and body temperature. In spite of the vast number of studies about the CART, the overall pictures about the CART functions are sketchy. First, there is a lack of information about cloned receptor, specific agonist and antagonist. Second, CART peptides are detected in discrete sets of neurons that can modulate countless activities and third; CART peptides exist in several fragments due to post-translational processing. For these reasons the overall picture about the CART peptides are sketchy and confounding.

Brain to bone: What is the contribution of the brain to skeletal homeostasis?

The brain, which governs most, if not all, physiological functions in the body, from the complexities of cognition, learning and memory, to the regulation of basal body temperature, heart rate and breathing, has long been known to affect skeletal health. In particular, the hypothalamus - located at the base of the brain in close proximity to the medial eminence, where the blood-brain-barrier is not as tight as in other regions of the brain but rather "leaky", due to fenestrated capillaries - is exposed to a variety of circulating body cues, such as nutrients (glucose, fatty acids, amino acids), and hormones (insulin, glucagon, leptin, adiponectin) [1-3].Information collected from the body via these peripheral cues is integrated by hypothalamic sensing neurons and glial cells [4-7], which express receptors for these nutrients and hormones, transforming these cues into physiological outputs. Interestingly, many of the same molecules, including leptin, adiponectin and insulin, regulate both energy and skeletal homeostasis. Moreover, they act on a common set of hypothalamic nuclei and their residing neurons, activating endocrine and neuronal systems, which ultimately fine-tune the body to new physiological states. This review will focus exclusively on the brain-to-bone pathway, highlighting the most important anatomical sites within the brain, which are known to affect bone, but not covering the input pathways and molecules informing the brain of the energy and bone metabolic status, covered elsewhere [8-10]. The discussion in each section will present side by side the metabolic and bone-related functions of hypothalamic nuclei, in an attempt to answer some of the long-standing questions of whether energy is affected by bone remodeling and homeostasis and vice versa.

Molecular mechanism of estrogen-mediated neuroprotection in the relief of brain ischemic injury

Background

This study aimed to explore the molecular mechanism of estrogen-mediated neuroprotection in the relief of cerebral ischemic injury. The gene expression profiles were downloaded from Gene Expression Omnibus database, and differentially expressed genes (DEGs) were identified using limma package in R software. Further, DEGs were subjected to Gene Ontology (GO) cluster analysis using online Gene Ontology Enrichment Analysis Software Toolkit and to GO functional enrichment analysis using DAVID software. Using the Gene Set Analysis Toolkit V2, enrichment analysis of Kyoto Encyclopedia of Genes and Genomes pathways was performed. In addition, protein-protein interaction (PPI) network was constructed using STRING database, and submodule analysis of PPI network. Lastly, the significant potential target sites of microRNAs (miRNAs) were predicted using Molecular Signatures Database, and the function analysis of targets of predicted miRNA was also performed using DAVID software.

Results

In total, 321 DEGs were screened in the estrogen-treated sample. The DEGs were mainly associated with intracellular signaling and metabolic pathways, such as calcium channel, calcineurin complex, insulin secretion, low-density lipoprotein reconstruction, and starch or sugar metabolism. In addition, GO enrichment analysis indicated an altered expression of the genes related to starch and sucrose metabolism, retinol metabolism, anti-apoptosis (eg., BDNF and ADAM17) and response to endogenous stimulus. The constructed PPI network comprised of 243 nodes and 590 interaction pairs, and four submodules were obtained from PPI network. Among the module d, four glutamate receptors as Gria4, Gria3, Grin3a and Grik4 were highlighted. Further, 5 novel potential regulatory miRNAs were also predicted. MIR-338 and MIR520D were closely associated with cell cycle, while the targets of MIR-376A and MIR-376B were only involved in cell soma.

Conclusions

The DEGs in estrogen-treated samples are closely associated with calcium channel, glutamate induced excitotoxicity and anti-apoptotic activity. In addition, some functionally significant DEGs such as BDNF, ADAM17, Gria4, Gria3, Grin3a, Grik4, Gys2 and Ugtla2, and new miRNAs like MIR-338 and MIR-376A were identified, which may serve as potential therapeutic targets for the effective treatment of cerebral ischemic injury.

Electronic supplementary material

The online version of this article (10.1186/s12863-018-0630-y) contains supplementary material, which is available to authorized users.

Cocaine‑ and amphetamine‑regulated transcript (CART) is associated with dopamine and is protective against ischemic stroke

Cocaine and amphetamine‑regulated transcript (CART) is a neuropeptide that can protect brains against ischemic injury. The aim of the present study was to investigate the effects of the CART within ischemic stroke and it possible mechanism. The expression levels of dopamine (DA) and CART in ischemic brain tissues of mice were measured following middle cerebral artery occlusion (MCAO). After receiving the treatment of DA and CART, the infarct volume of brain was measured in mice with MCAO. In addition, the function and potential mechanism of CART in ischemic stroke were further investigated. DA and CART expression was significantly decreased in mice with MCAO compared with normal control mice. Treatment of mice with MCAO with exogenous CART significantly decreased the extent of brain injury compared with untreated mice with MCAO. Treatment with exogenous CART promoted the survival of ex vivo neurons following oxygen‑glucose deprivation (OGD), while exogenous DA induced CART mRNA expression in a dose‑dependent manner, which suggested an association between CART and DA. Apoptosis of ex vivo neurons was significantly increased following OGD, however treatment with exogenous CART significantly inhibited this effect. The potential mechanism of CART was determined to be associated with inflammatory cytokines and related apoptotic genes. CART therefore appears to be associated with DA in its effect on ischemic stroke and is protective against brain injury following ischemic stroke by reducing inflammation activation; it may provide a promising means to treat ischemic stroke patients.

The Intersection of Central Dopamine System and Stroke: Potential Avenues Aiming at Enhancement of Motor Recovery

Dopamine, a major neurotransmitter, plays a role in a wide range of brain sensorimotor functions. Parkinson's disease and schizophrenia are two major human neuropsychiatric disorders typically associated with dysfunctional dopamine activity levels, which can be alleviated through the druggability of the dopaminergic systems. Meanwhile, several studies suggest that optimal brain dopamine activity levels are also significantly impacted in other serious neurological conditions, notably stroke, but this has yet to be fully appreciated at both basic and clinical research levels. This is of utmost importance as there is a need for better treatments to improve recovery from stroke. Here, we discuss the state of knowledge regarding the modulation of dopaminergic systems following stroke, and the use of dopamine boosting therapies in animal stroke models to improve stroke recovery. Indeed, studies in animals and humans show stroke leads to changes in dopamine functioning. Moreover, evidence from animal stroke models suggests stimulation of dopamine receptors may be a promising therapeutic approach for enhancing motor recovery from stroke. With respect to the latter, we discuss the evidence for several possible receptor-linked mechanisms by which improved motor recovery may be mediated. One avenue of particular promise is the subtype-selective stimulation of dopamine receptors in conjunction with physical therapy. However, results from clinical trials so far have been more mixed due to a number of potential reasons including, targeting of the wrong patient populations and use of drugs which modulate a wide array of receptors. Notwithstanding these issues, it is hoped that future research endeavors will assist in the development of more refined dopaminergic therapeutic approaches to enhance stroke recovery.

Improving Neurorepair in Stroke Brain Through Endogenous Neurogenesis-Enhancing Drugs

Stroke induces not only cell death but also neurorepair. De novo neurogenesis has been found in the subventricular zone of the adult mammalian brain days after stroke. Most of these newly generated cells die shortly after the insult. Recent studies have shown that pharmacological manipulation can improve the survival of endogenous neuroprogenitor cells and neural regeneration in stroke rats. As these drugs target the endogenous reparative processes that occur days after stroke, they may provide a prolonged window for stroke therapy. Here, we discuss endogenous neurogenesis-enhancing drugs and review the general status of stroke therapeutics in evaluating the field of pharmacotherapy for stroke.

Repurposing and repositioning neurosteroids in the treatment of traumatic brain injury: A report from the trenches

The field of neuroprotection after brain injuries has been littered with failed clinical trials. Finding a safe and effective treatment for acute traumatic brain injury remains a serious unmet medical need. Repurposing drugs that have been in use for other disorders is receiving increasing attention as a strategy to move candidate drugs more quickly to trial while reducing the very high cost of new drug development. This paper describes our own serendipitous discovery of progesterone's neuroprotective potential, and the strategies we are using in repurposing and developing this hormone for use in brain injuries-applications very different from its classical uses in treating disorders of the reproductive system. We have been screening and testing a novel analog that maintains progesterone's therapeutic properties while overcoming its physiochemical challenges, and testing progesterone in combination treatment with another pleiotropic hormone, vitamin D. Finally, our paper, in the context of the problems and pitfalls we have encountered, surveys some of the factors we found to be critical in the clinical translation of repurposed drugs. This article is part of the Special Issue entitled 'Drug Repurposing: old molecules, new ways to fast track drug discovery and development for CNS disorders'.

Blood-brain barrier dysfunction and recovery after ischemic stroke

The blood-brain barrier (BBB) plays a vital role in regulating the trafficking of fluid, solutes and cells at the blood-brain interface and maintaining the homeostatic microenvironment of the CNS. Under pathological conditions, such as ischemic stroke, the BBB can be disrupted, followed by the extravasation of blood components into the brain and compromise of normal neuronal function. This article reviews recent advances in our knowledge of the mechanisms underlying BBB dysfunction and recovery after ischemic stroke. CNS cells in the neurovascular unit, as well as blood-borne peripheral cells constantly modulate the BBB and influence its breakdown and repair after ischemic stroke. The involvement of stroke risk factors and comorbid conditions further complicate the pathogenesis of neurovascular injury by predisposing the BBB to anatomical and functional changes that can exacerbate BBB dysfunction. Emphasis is also given to the process of long-term structural and functional restoration of the BBB after ischemic injury. With the development of novel research tools, future research on the BBB is likely to reveal promising potential therapeutic targets for protecting the BBB and improving patient outcome after ischemic stroke.

Drug treatments that optimize endogenous neurogenesis as a therapeutic option for stroke

Cell death and neurogenesis have been examined after stroke in the subventricular zone of the adult mammalian brain. New research focuses on the use of drugs to improve the viability of neural progenitor cells in rats after stroke. The aim of the drugs is to lengthen the timeframe for stroke therapy by targeting the endogenous repair mechanism that follows injury. In this paper, we look at the broad state of stroke therapy to assess the effectiveness of endogenous neurogenesis-enhancing drugs on stroke. This paper is a review article. Referred literature in this paper has been listed in the reference section. The data sets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors’ experiences.

Proteomic Analysis of the Peri-Infarct Area after Human Umbilical Cord Mesenchymal Stem Cell Transplantation in Experimental Stroke

Among various therapeutic approaches for stroke, treatment with human umbilical cord mesenchymal stem cells (hUC-MSCs) has acquired some promising results. However, the underlying mechanisms remain unclear. We analyzed the protein expression spectrum of the cortical peri-infarction region after ischemic stroke followed by treatment with hUC-MSCs, and found 16 proteins expressed differentially between groups treated with or without hUC-MSCs. These proteins were further determined by Gene Ontology term analysis and network with CD200-CD200R1, CCL21-CXCR3 and transcription factors. Three of them: Abca13, Grb2 and Ptgds were verified by qPCR and ELISA. We found the protein level of Abca13 and the mRNA level of Grb2 consistent with results from the proteomic analysis. Finally, the function of these proteins was described and the potential proteins that deserve to be further studied was also highlighted. Our data may provide possible underlying mechanisms for the treatment of stroke using hUC-MSCs.

Post-treatment with cocaine- and amphetamine-regulated transcript enhances infarct resolution, reinnervation, and angiogenesis in stroke rats - an MRI study

Recent studies have shown that post-treatment with cocaine- and amphetamine-regulated transcript (CART) has neuroregenerative effects in animal models of stroke. The purpose of this study was to characterize CART-mediated neuronal and vascular repairments using non-invasive MRI techniques. Adult male rats were subjected to a 90 min middle cerebral artery occlusion (MCAo). Animals were separated into two groups with similar infarction sizes, measured by T2 -weighted MRI on Day 2 after MCAo, and were treated with CART or vehicle intranasally from Day 3 to Day 12. Diffusion tensor imaging was used to examine changes in plasticity of white matter elements. Susceptibility-weighted imaging (SWI) was used to measure angiogenesis. Post-treatment with CART significantly increased fractional anisotropy (FA) in lesioned cortex on Days 10 and 25 post stroke. A significant correlation between the behavioral recovery in body asymmetry and the change in FA was shown, suggesting that behavioral recovery was associated with reinnervation to the lesioned hemisphere. CART also increased the intensity of SWI and the immunoreactivity of the vascular marker alpha-smooth muscle actin in lesioned cortex. Together, our data support a non-invasive treatment strategy for stroke through angiogenesis and reinnervation by CART. Copyright © 2016 John Wiley & Sons, Ltd.

Neuroprotective effects of ginseng protein on PI3K/Akt signaling pathway in the hippocampus of D-galactose/AlCl3 inducing rats model of Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer disease (AD) is a progressive neurodegenerative disease, with progressive memory loss, cognitive deterioration, and behavioral disorders. Ginseng (Panax ginseng C.A. Meyer) is widely used in China to treat various kinds of nervous system disorders. The study aimed to explore the therapeutic effect of ginseng protein (GP) on Alzheimer's disease and its correlation with the PI3K/Akt signaling pathway to understand the mechanism underlying the neuroprotective effect of ginseng.

MATERIAL AND METHODS

The AD rat model was established by intraperitoneally injecting D-galactose [60mg/(kgd)] followed by intragastrically administering AlCl3 [40mg/(kgd)] for 90 days. From day 60, the GP groups were intragastrically administered with GP 0.05 or 0.1g/kg twice daily for 30 days. The ethology of rats was tested by Morris water maze test. The content of Aβ1-42 and p-tau in the hippocampus of rats was detected by enzyme-linked immunosorbent assay. The expression of mRNAs and proteins of PI3K, Akt, phosphorylated Akt (p-Akt), Bcl-2, and Bax in the hippocampus was detected by real-time quantitative reverse transcription polymerase chain reaction and Western blot assay.

RESULTS

GP was found to significantly improve the memory ability of AD rats and prolong the times of crossing the platform and the percentage of residence time in the original platform quadrant of spatial probe test. GP also reduced the content of Aβ1-42 and p-tau and improved the mRNA and protein expression of PI3K, p-Akt/Akt, and Bcl-2/Bax in the hippocampus.

CONCLUSIONS

GP could improve the memory ability and reduce the content of Aβ1-42 and p-tau in AD rats. The anti-AD effects of GP were in part mediated by PI3K/Akt signaling pathway activation.

The Deep Correlation between Energy Metabolism and Reproduction: A View on the Effects of Nutrition for Women Fertility

In female mammals, mechanisms have been developed, throughout evolution, to integrate environmental, nutritional and hormonal cues in order to guarantee reproduction in favorable energetic conditions and to inhibit it in case of food scarcity. This metabolic strategy could be an advantage in nutritionally poor environments, but nowadays is affecting women's health. The unlimited availability of nutrients, in association with reduced energy expenditure, leads to alterations in many metabolic pathways and to impairments in the finely tuned inter-relation between energy metabolism and reproduction, thereby affecting female fertility. Many energetic states could influence female reproductive health being under- and over-weight, obesity and strenuous physical activity are all conditions that alter the profiles of specific hormones, such as insulin and adipokines, thus impairing women fertility. Furthermore, specific classes of nutrients might affect female fertility by acting on particular signaling pathways. Dietary fatty acids, carbohydrates, proteins and food-associated components (such as endocrine disruptors) have per se physiological activities and their unbalanced intake, both in quantitative and qualitative terms, might impair metabolic homeostasis and fertility in premenopausal women. Even though we are far from identifying a "fertility diet", lifestyle and dietary interventions might represent a promising and invaluable strategy to manage infertility in premenopausal women.

CART modulates the effects of levodopa in rat model of Parkinson's disease

Parkinson's disease (PD) is an age-related disorder characterized by a progressive degeneration of dopaminergic neurons of substantia nigra (SN). The neuropeptide cocaine- and amphetamine-regulated transcript (CART) is known to closely interact with the dopamine system and regulate psychomotor activity. We screened the effectiveness of CART in reversing the symptoms of PD in a rat model. PD like condition was induced by administering 6-hydroxydopamine (6-OHDA) directly in the SN of the right side. Fifteen days later, intraperitoneal (IP) treatment with apomorphine hydrochloride to these rats, resulted in contralateral rotations in the rotation test chamber suggesting induction of PD-like symptoms. This action of apomorphine was significantly attenuated by intracerebroventricular (ICV) treatment with CART and potentiated by CART antibody. IP treatment with levodopa also produced contralateral rotation in PD induced rats, and showed anti-Parkinson-like action. Prior treatment with CART via ICV route potentiated the anti-Parkinsonian effects of levodopa, while CART antibody produced opposite effects. CART treatment per se, to PD induced rats produced ipsilateral rotations, suggesting that the peptide may promote the endogenous release of dopamine from intact neurons. While CART-immunoreactivity in arcuate nucleus, paraventricular nucleus, striatum, substantia nigra, ventral tegmental area and locus coeruleus was reduced in the PD induced rats, levodopa treatment restored the expression of CART-immunoreactivity in these nuclei. These results suggest that endogenous CART might closely interact with the dopamine containing SN-striatal pathway which is known to profoundly influence the motor system. The study underscores the importance of CART as a potential therapeutic agent in the treatment of PD.

Icariin attenuates cerebral ischemia-reperfusion injury through inhibition of inflammatory response mediated by NF-κB, PPARα and PPARγ in rats

Icariin (ICA), an active flavonoid extracted from Chinese medicinal herb Epimedii, has been reported to exhibit many pharmacological effects including alleviating brain injury. However, little is known about the protection of ICA on ischemic stroke. Hence, this study was designed to investigate the neuroprotective effect of ICA and explore its underlying mechanisms on ischemic stroke induced by cerebral ischemia-reperfusion (I/R) injury in rats. The animals were pretreated with ICA at doses of 10, 30mg/kg twice per day for 3 consecutive days followed by cerebral I/R injury induced by middle cerebral artery occlusion (MCAO) for 2h and reperfusion for 24h. Neurological function and infarct volume were observed at 24h after reperfusion, the protein expression levels of interleukin-1β (IL-1β), transforming growth factor-β1 (TGF-β1), PPARα and PPARγ, inhibitory κB-α (IκB-α) degradation and nuclear factor κB (NF-κB) p65 phosphorylation were detected by Western blot, respectively. It was found that pretreatment with ICA could decrease neurological deficit score, diminish the infarct volume, and reduce the protein levels of IL-1β and TGF-β1. Moreover, ICA suppressed IκB-α degradation and NF-κB activation induced by I/R. Furthermore, the present study also showed that ICA up-regulated PPARα and PPARγ protein levels. These findings suggest that ICA has neuroprotective effect on ischemic stroke in rats through inhibition of inflammatory responses mediated by NF-κB and PPARα and PPARγ.

CART treatment improves memory and synaptic structure in APP/PS1 mice

Major characteristics of Alzheimer’s disease (AD) include deposits of β-amyloid (Aβ) peptide in the brain, loss of synapses, and cognitive dysfunction. Cocaine- and amphetamine-regulated transcript (CART) has recently been reported to attenuate Aβ-induced toxicity. In this study, CART localization in APP/PS1 mice was characterized and the protective effects of exogenous CART treatment were examined. Compared to age-matched wild type mice, 8-month-old APP/PS1 mice had significantly greater CART immunoreactivity in the hippocampus and cortex. A strikingly similar pattern of Aβ plaque-associated CART immunoreactivity was observed in the cortex of AD cases. Treatment of APP/PS1 mice with exogenous CART ameliorated memory deficits; this effect was associated with improvements in synaptic ultrastructure and long-term potentiation, but not a reduction of the Aβ plaques. Exogenous CART treatment in APP/PS1 mice prevented depolarization of the mitochondrial membrane and stimulated mitochondrial complex I and II activities, resulting in an increase in ATP levels. CART treatment of APP/PS1 mice also reduced reactive oxygen species and 4-hydroxynonenal, and mitigated oxidative DNA damage. In summary, CART treatment reduced multiple neuropathological measures and improved memory in APP/PS1 mice, and may therefore be a promising and novel therapy for AD.

Human umbilical cord mesenchymal stem cells protect against ischemic brain injury in mouse by regulating peripheral immunoinflammation

Current treatments for ischemic stroke are limited, stem cell transplantation offers great potential as a therapeutic strategy. The present study was undertaken to determine whether human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) could improve brain injury after middle cerebral artery occlusion (MCAO) through modulating peripheral immunoinflammation. The study showed that neurological deficit was ameliorated and brain edema, infarct volume was significantly decreased from 72 h to 1 week post-MCAO with hUC-MSCs treatment via tail vein injection within 30 mins after stroke; hUC-MSCs attenuated the levels of inflammatory factors including IL-1, TNF-α, IL-23, IL-17 and IL-10 in peripheral blood serum and ischemia hemisphere after stroke; hUC-MSCs significantly decreased the level of Th17 cells at 24h and increased the level of Tregs at 72 h post-MCAO in peripheral immune system; the level of TGF-β in blood serum was enhanced by hUC-MSCs. In conclusion, our findings suggested that hUC-MSCs had neuroprotection in MCAO mice by TGF-β modulating peripheral immune and hUC-MSCs may be as a potential therapy for ischemic stroke.

Mechanism of the sex difference in endothelial dysfunction after stroke

Stroke, the number four cause of death in the United States, is a greatly debilitating event resulting from insufficient blood supply to the brain (cerebral ischemia). Endothelial dysfunction, primarily characterized by dampened endothelial- dependent vasodilation, is a major contributor to the development and outcome of stroke. This review discusses the role of soluble epoxide hydrolase (sEH), an enzyme responsible for the degradation of vasoprotective eicosatrienoic acids (EETs), in the context of the cerebral vasculature and its contribution to the sexual dimorphic nature of stroke.

CART in the brain of vertebrates: circuits, functions and evolution

Cocaine- and amphetamine-regulated transcript peptide (CART) with its wide distribution in the brain of mammals has been the focus of considerable research in recent years. Last two decades have witnessed a steady rise in the information on the genes that encode this neuropeptide and regulation of its transcription and translation. CART is highly enriched in the hypothalamic nuclei and its relevance to energy homeostasis and neuroendocrine control has been understood in great details. However, the occurrence of this peptide in a range of diverse circuitries for sensory, motor, vegetative, limbic and higher cortical areas has been confounding. Evidence that CART peptide may have role in addiction, pain, reward, learning and memory, cognition, sleep, reproduction and development, modulation of behavior and regulation of autonomic nervous system are accumulating, but an integration has been missing. A steady stream of papers has been pointing at the therapeutic potentials of CART. The current review is an attempt at piecing together the fragments of available information, and seeks meaning out of the CART elements in their anatomical niche. We try to put together the CART containing neuronal circuitries that have been conclusively demonstrated as well as those which have been proposed, but need confirmation. With a view to finding out the evolutionary antecedents, we visit the CART systems in sub-mammalian vertebrates and seek the answer why the system is shaped the way it is. We enquire into the conservation of the CART system and appreciate its functional diversity across the phyla.

Energy metabolism and fertility: a balance preserved for female health

In female animals, energy metabolism and fertility are tightly connected, and reciprocally regulated. However, the relative contributions of metabolic and reproductive pathways have changed over the course of evolution. In oviparous animals, metabolic factors take precedence over fertility, enabling egg production to be inhibited in a nutritionally poor environment. By contrast, in placental mammals, the opposite occurs: the need to feed a developing embryo and neonate forces metabolic pathways to adapt to these reproductive needs. This physiological necessity explains why in female mammals alterations of gonadal activity, including age-dependent cessation of ovarian functions, are associated with a disruption of metabolic homeostasis and consequent inflammatory reactions that trigger the onset of metabolic, cardiovascular, skeletal and neural pathologies. This Review discusses how metabolic homeostasis and reproductive functions interact to optimize female fertility and explains the pathogenic mechanisms underlying the disordered energy metabolism associated with human ovarian dysfunction owing to menopause, polycystic ovary syndrome and Turner syndrome. Finally, this article highlights how hormone replacement therapy might aid the restoration of metabolic homeostasis in women with ovarian dysfunction.

Neurotransmitter CART as a New Therapeutic Candidate for Parkinson's Disease

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. To date, there is no effective treatment that halts its progression. Increasing evidence indicates that mitochondria play an important role in the development of PD. Hence mitochondria-targeted approaches or agents may have therapeutic promise for treatment of the disease. Neuropeptide CART (cocaine-amphetamine-regulated transcript), a hypothalamus and midbrain enriched neurotransmitter with an antioxidant property, can be found in mitochondria, which is the main source of reactive oxygen species. Systemic administration of CART has been found to ameliorate dopaminergic neuronal loss and improve motor functions in a mouse model of PD. In this article, we summarize recent progress in studies investigating the relationship between CART, dopamine, and the pathophysiology of PD, with a focus on mitochondria-related topics.

Stroke neuroprotection: oestrogen and insulin-like growth factor-1 interactions and the role of microglia

Oestrogen has been shown to be neuroprotective for stroke and other neural injury models. Oestrogen promotes a neuroprotective phenotype through myriad actions, including stimulating neurogenesis, promoting neuronal differentiation and survival, suppressing neuroinflammation and maintaining the integrity of the blood-brain barrier. At the molecular level, oestrogen directly modulates genes that are beneficial for repair and regeneration via the canonical oestrogen receptor. Increasingly, evidence indicates that oestrogen acts in concert with growth factors to initiate neuroprotection. Oestrogen and insulin-like growth factor (IGF)-1 act cooperatively to influence cell survival, and combined steroid hormone/growth factor interaction has been well documented in the context of neurones and astrocytes. Here, we summarise the evidence that oestrogen-mediated neuroprotection is critically dependent on IGF-1 signalling, and specifically focus on microglia as the source of IGF-1 and the locus of oestrogen-IGF-1 interactions in stroke neuroprotection.

Effect of cocaine use on outcomes in traumatic brain injury

Context:

Animal and molecular studies have shown that cocaine exerts a neuroprotective effect against cerebral ischemia.

Aims:

To determine if the presence of cocaine metabolites on admission following traumatic brain injury (TBI) is associated with better outcomes.

Settings and Design:

Level-1 trauma center, retrospective cohort.

Materials and Methods:

After obtaining Institutional Review Board (IRB) approval, the trauma registry was searched from 2006 to 2009 for all patients aged 15-55 years with blunt head trauma and non-head AIS <3. Exclusion criteria were pre-existing brain pathology and death within 30 min of admission. The primary outcome was in-hospital mortality; secondary outcomes were hospital length of stay (LOS), and Glasgow Outcome Score (GOS).

Statistical Analysis:

Logistic regression was used to determine the independent effect of cocaine on mortality. Hospital LOS was compared with multiple linear regression.

Results:

A total of 741 patients met criteria and had drug screens. The screened versus unscreened groups were similar. Cocaine positive patients were predominantly African-American (46% vs. 21%, P < 0.0001), older (40 years vs. 30 years, P < 0.0001), and had ethanol present more often (50.7% vs. 37.8%, P = 0.01). There were no differences in mortality (cocaine-positive 1.4% vs. cocaine-negative 2.7%, P = 0.6) on both univariate and multivariate analysis.

Conclusions:

Positive cocaine screening was not associated with mortality in TBI. An effect may not have been detected because of the low mortality rate. LOS is affected by many factors unrelated to the injury and may not be a good surrogate for recovery. Similarly, GOS may be too coarse a measure to identify a benefit.

CART attenuates endoplasmic reticulum stress response induced by cerebral ischemia and reperfusion through upregulating BDNF synthesis and secretion

Cocaine and amphetamine regulated transcript (CART), a neuropeptide, has shown strong neuroprotective effects against cerebral ischemia and reperfusion (I/R) injury in vivo and in vitro. Here, we report a new effect of CART on ER stress which is induced by cerebral I/R in a rat model of middle cerebral artery occlusion (MCAO) or by oxygen and glucose deprivation (OGD) in cultured cortical neurons, as well as a new functionality of BDNF in the neuroprotection by CART against the ER stress in cerebral I/R. The results showed that CART was effective in reducing the neuronal apoptosis and expression of ER stress markers (GRP78, CHOP and cleaved caspase12), and increasing the BDNF expression in I/R injury rat cortex both in vivo and in vitro. In addition, the effects of CART on ischemia-induced neuronal apoptosis and ER stress were suppressed by tyrosine receptor kinase B (TrkB) IgG, whereas the effects of CART on BDNF transcription, synthesis and secretion were abolished by CREB siRNA. This work suggests that CART is functional in inhibiting the cerebral I/R-induced ER stress and neuronal apoptosis by facilitating the transcription, synthesis and secretion of BDNF in a CREB-dependent way.

Gene responses in the central nervous system of zebrafish embryos exposed to the neurotoxicant methyl mercury

Methyl mercury (MeHg) is a neurotoxicant with adverse effects on the development of the nervous system from fish to man. Despite a detailed understanding of the molecular mechanisms by which MeHg affects cellular homeostasis, it is still not clear how MeHg causes developmental neurotoxicity. We performed here a genome-wide transcriptional analysis of MeHg-exposed zebrafish embryos and combined this with a whole-mount in situ expression analysis of 88 MeHg-affected genes. The majority of the analyzed genes showed tissue- and region-restricted responses in various organs and tissues. The genes were linked to gene ontology terms like oxidative stress, transport and cell protection. Areas even within the central nervous system (CNS) are affected differently resulting in distinct cellular stress responses. Our study revealed an unexpected heterogeneity in gene responses to MeHg exposure in different tissues and neuronal subregions, even though the known molecular action of MeHg would predict a similar burden of exposed cells. The overall structure of the developing brain of MeHg-exposed embryos appeared normal, suggesting that the mechanism leading to differentiation of the CNS is not overtly affected by exposure to MeHg. We propose that MeHg disturbs the function of the CNS by disturbing the cellular homeostasis. As these cellular stress responses comprise genes that are also involved in normal neuronal activity and learning, MeHg may affect the developing CNS in a subtle manner that manifests itself in behavioral deficits.

Roles of cocaine- and amphetamine-regulated transcript in the central nervous system

1. Cocaine- and amphetamine-regulated transcript (CART), first isolated from the ovine hypothalamus, is a potential neurotransmitter widely distributed throughout the central and peripheral nervous systems, as well as in endocrine cells in the pituitary and adrenal glands, pancreatic islets and stomach. 2. Numerous studies have established the role of CART in food intake, maintenance of bodyweight, stress control, reward and pain transmission. Recently, it was demonstrated that CART, as a neurotrophic peptide, had a cerebroprotective against focal ischaemic stroke and inhibited the neurotoxicity of β-amyloid protein, which focused attention on the role of CART in the central nervous system (CNS) and neurological diseases. 3. In fact, little is known about the way in which CART peptide interacts with its receptors, initiates downstream cascades and finally exerts its neuroprotective effect under normal or pathological conditions. The literature indicates that there are many factors, such as regulation of the immunological system and protection against energy failure, that may be involved in the cerebroprotection afforded by CART. 4. The present review provides a brief summary of the current literature on CART synthesis and active fragments, its distribution in the CNS and, in particular, the role of CART peptide (and its receptors and signalling) in neurological diseases.

NDRG2 is a novel p53-associated regulator of apoptosis in C6-originated astrocytes exposed to oxygen-glucose deprivation

N-myc downstream-regulated gene 2 (NDRG2) has been documented to be a pro-differentiative and anti-proliferative gene in cancer research. Our previous study found a significant NDRG2 up-regulation in reactive astrocytes of penumbra after transient focal cerebral ischemia, which was parallel to the enhancement of TUNEL-positive signals. However, it is still uncertain whether NDRG2 participates in cellular apoptosis induced by ischemia-reperfusion injury in brain. In this study, we investigated the role of NDRG2 in cellular apoptosis induced by oxygen-glucose deprivation (OGD) in IL-6-differentiated C6 glioma cells. The results showed that NDRG2 was up-regulated and translocated from the cytoplasm to the nucleus after OGD exposure. NDRG2 over-expression exhibited an anti-proliferative effect and increased the Bax/Bcl-2 ratio after OGD exposure, while NDRG2 silencing promoted the cellular proliferation and attenuated the up-regulation of Bax/Bcl-2 ratio. The pro-apoptotic effect of p53 was verified by the results in which p53 silencing greatly reduced the percentage of OGD-induced apoptotic cells. p53 silencing also reduced the OGD-induced NDRG2 up-regulation. However, over-expression of p53 did not further improve the NDRG2 up-regulation. In conclusion, NDRG2 is a p53-associated regulator of apoptosis in C6-originated astrocytes after OGD exposure. These findings bring insight to the roles of NDRG2 in ischemic-hypoxic injury and provide potential targets for future clinical therapies on stroke.

Hopeahainol A attenuates memory deficits by targeting β-amyloid in APP/PS1 transgenic mice

Increasing evidence demonstrates that amyloid beta (Aβ) elicits mitochondrial dysfunction and oxidative stress, which contributes to the pathogenesis of Alzheimer's disease (AD). Identification of the molecules targeting Aβ is thus of particular significance in the treatment of AD. Hopeahainol A (HopA), a polyphenol with a novel skeleton obtained from Hopea hainanensis, is potentially acetylcholinesterase-inhibitory and anti-oxidative in H(2)O(2)-treated PC12 cells. In this study, we reported that HopA might bind to Aβ(1-42) directly and inhibit the Aβ(1-42) aggregation using a combination of molecular dynamics simulation, binding assay, transmission electron microscopic analysis and staining technique. We also demonstrated that HopA decreased the interaction between Aβ(1-42) and Aβ-binding alcohol dehydrogenase, which in turn reduced mitochondrial dysfunction and oxidative stress in vivo and in vitro. In addition, HopA was able to rescue the long-term potentiation induction by protecting synaptic function and attenuate memory deficits in APP/PS1 mice. Our data suggest that HopA might be a promising drug for therapeutic intervention in AD.

CART peptide induces neuroregeneration in stroke rats

Utilizing a classic stroke model in rodents, middle cerebral artery occlusion (MCAo), we describe a novel neuroregenerative approach using the repeated intranasal administration of cocaine- and amphetamine-regulated transcript (CART) peptide starting from day 3 poststroke for enhancing the functional recovery of injured brain. Adult rats were separated into two groups with similar infarction sizes, measured by magnetic resonance imaging on day 2 after MCAo, and were treated with CART or vehicle. The CART treatment increased CART level in the brain, improved behavioral recovery, and reduced neurological scores. In the subventricular zone (SVZ), CART enhanced immunolabeling of bromodeoxyuridine, a neural progenitor cell marker Musashi-1, and the proliferating cell nuclear antigen, as well as upregulated brain-derived neurotrophic factor (BDNF) mRNA. AAV-GFP was locally applied to the SVZ to examine migration of SVZ cells. The CART enhanced migration of GFP(+) cells from SVZ toward the ischemic cortex. In SVZ culture, CART increased the size of neurospheres. The CART-mediated cell migration from SVZ explants was reduced by anti-BDNF blocking antibody. Using (1)H-MRS (proton magnetic resonance spectroscopy), increases in N-acetylaspartate levels were found in the lesioned cortex after CART treatment in stroke brain. Cocaine- and amphetamine-regulated transcript increased the expression of GAP43 and fluoro-ruby fluorescence in the lesioned cortex. In conclusion, our data suggest that intranasal CART treatment facilitates neuroregeneration in stroke brain.

Expression patterns of histone deacetylases in experimental stroke and potential targets for neuroprotection

1. Histone deacetylase (HDAC) inhibitors exert neuroprotection in both cellular and animal models of ischaemic stroke. However, which HDAC isoform (or isoforms) mediates this beneficial effect has not yet been determined. 2. In the present study, gene levels of the HDAC isoforms were determined in the mouse cortex using reverse transcription-polymerase chain reaction (RT-PCR), whereas changes in the expression of individual zinc-dependent HDAC family members were evaluated by western blotting, 3, 12, 24 and 48 h after cerebral ischaemia induced by transient middle cerebral artery occlusion in male Kunming mice. 3. The HDAC isoforms HDAC1-11 were all expressed in the mouse cortex and differentially affected by cerebral ischaemia. Notably, there was a substantial increase in HDAC3, HDAC6 and HDAC11 expression during the early phases of experimental stroke, indicating their contribution to stroke pathogenesis. Furthermore, induction of HDAC3 and HDAC6 in cortical neurons by ischaemic stroke was confirmed in vivo and in vitro using double-labelled immunostaining and RT-PCR, respectively. Therefore, small hairpin (sh) RNAs were used to selectively knock down HDAC3 or HDAC6. This knockdown appreciably promoted the survival of cortical neurons subjected to oxygen and glucose deprivation. 4. The findings of the present study demonstrate the expression patterns of HDAC isoforms during experimental ischaemic stroke. Furthermore, HDAC3 and HDAC6 were identified as potential mediators in the neurotoxicity of ischaemic stroke, suggesting that specific therapeutic approaches may be considered according to HDAC subtype.

Cocaine- and amphetamine-regulated transcript (CART) protects beta cells against glucotoxicity and increases cell proliferation

Cocaine- and amphetamine-regulated transcript (CART) is an islet peptide that promotes glucose-stimulated insulin secretion in beta cells via cAMP/PKA-dependent pathways. In addition, CART is a regulator of neuronal survival. In this study, we examined the effect of exogenous CART 55-102 on beta cell viability and dissected its signaling mechanisms. Evaluation of DNA fragmentation and chromatin condensation revealed that CART 55-102 reduced glucotoxicity-induced apoptosis in both INS-1 (832/13) cells and isolated rat islets. Glucotoxicity in INS-1 (832/13) cells also caused a 50% reduction of endogenous CART protein. We show that CART increased proliferation in INS-1 (832/13) cells, an effect that was blocked by PKA, PKB, and MEK1 inhibitors. In addition, CART induced phosphorylation of CREB, IRS, PKB, FoxO1, p44/42 MAPK, and p90RSK in INS-1 (832/13) cells and isolated rat islets, all key mediators of cell survival and proliferation. Thus, we demonstrate that CART 55-102 protects beta cells against glucotoxicity and promotes proliferation. Taken together our data point to the potential use of CART in therapeutic interventions targeted at enhancing functional beta cell mass and long-term insulin secretion in T2D.

Neuron-restrictive silencer factor (NRSF) represses cocaine- and amphetamine-regulated transcript (CART) transcription and antagonizes cAMP-response element-binding protein signaling through a dual NRSE mechanism

Cocaine- and amphetamine-regulated transcript (CART) peptide plays a pivotal role in neuroprotection against stroke-related brain injury. However, the regulatory mechanism on CART transcription, especially the repression mechanism, is not fully understood. Here, we show that the transcriptional repressor neuron-restrictive silencer elements (NRSF, also known as REST) represses CART expression through direct binding to two NRSF-binding elements (NRSEs) in the CART promoter and intron 1 (named pNRSE and iNRSE, respectively). EMSA show that NRSF binds to pNRSE and iNRSE directly in vitro. ChIP assays show that NRSF recruits differential co-repressor complexes including CoREST and HDAC1 to these NRSEs. The presence of both NRSEs is required for efficient repression of CART transcription as indicated by reporter gene assays. NRSF overexpression antagonizes forskolin-mediated up-regulation of CART mRNA and protein. Ischemia insult triggered by oxygen-glucose deprivation (OGD) enhances NRSF mRNA levels and then NRSF antagonizes the CREB signaling on CART activation, leading to augmented cell death. Depletion of NRSF in combination with forskolin treatment increases neuronal survival after ischemic insult. These findings reveal a novel dual NRSE mechanism by which NRSF represses CART expression and suggest that NRSF may serve as a therapeutic target for stroke treatment.

Gene expression alterations in Rocky Mountain elk infected with chronic wasting disease

Chronic wasting disease (CWD) is an invariably fatal neurologic disease that naturally infects mule deer, white tailed deer and elk. The understanding of CWD neurodegeneration at a molecular level is very limited. In this study, microarray analysis was performed to determine changes in the gene expression profiles in six different tissues including brain, midbrain, thalamus, spleen, RPLN and tonsil of CWD-infected elk in comparison to non-infected healthy elk, using 24,000 bovine specific oligo probes. In total, 329 genes were found to be differentially expressed (> 2.0-fold) between CWD negative and positive brain tissues, with 132 genes upregulated and 197 genes downregulated. There were 249 DE genes in the spleen (168 up- and 81 downregulated), 30 DE genes in the retropharyngeal lymph node (RPLN) (18 up- and 12 downregulated), and 55 DE genes in the tonsil (21 up- and 34 downregulated). Using Gene Ontology (GO), the DE genes were assigned to functional groups associated with cellular process, biological regulation, metabolic process, and regulation of biological process. For all brain tissues, the highest ranking networks for DE genes identified by Ingenuity Pathway Analysis (IPA) were associated with neurological disease, cell morphology, cellular assembly and organization. Quantitative real-time PCR (qRT-PCR) validated the expression of DE genes primarily involved in different regulatory pathways, including neuronal signaling and synapse function, calcium signaling, apoptosis and cell death and immune cell trafficking and inflammatory response. This is the first study to evaluate altered gene expression in multiple organs including brain from orally infected elk and the results will improve our understanding of CWD neurodegeneration at the molecular level.

Ras family small GTPase-mediated neuroprotective signaling in stroke

Selective neuronal cell death is one of the major causes of neuronal damage following stroke, and cerebral cells naturally mobilize diverse survival signaling pathways to protect against ischemia. Importantly, therapeutic strategies designed to improve endogenous anti-apoptotic signaling appear to hold great promise in stroke treatment. While a variety of complex mechanisms have been implicated in the pathogenesis of stroke, the overall mechanisms governing the balance between cell survival and death are not well-defined. Ras family small GTPases are activated following ischemic insults, and in turn, serve as intrinsic switches to regulate neuronal survival and regeneration. Their ability to integrate diverse intracellular signal transduction pathways makes them critical regulators and potential therapeutic targets for neuronal recovery after stroke. This article highlights the contribution of Ras family GTPases to neuroprotective signaling cascades, including mitogen-activated protein kinase (MAPK) family protein kinase- and AKT/PKB-dependent signaling pathways as well as the regulation of cAMP response element binding (CREB), Forkhead box O (FoxO) and hypoxiainducible factor 1(HIF1) transcription factors, in stroke.