Cell death pathways and autophagy in the central nervous system and its involvement in neurodegeneration, immunity and central nervous system infection: to die or not to die--that is the question

Synergistic Neuroprotective Effects of Mature Silkworm and Angelica gigas Against Scopolamine-Induced Mild Cognitive Impairment in Mice and H2O2-Induced Cell Death in HT22 Mouse Hippocampal Neuronal Cells

We previously reported that mature Bombyx mori silkworm (SW) ameliorated scopolamine (Sco)-induced amnesia, and Angelica gigas (AG) prevented cognitive impairment. SW is known for its gastroprotective effects such as improving liver function and alleviating the effects of Parkinson's disease. AG is known for its neuroprotective effects and for lowering the effects of low-density lipoprotein cholesterol. However, the neuroprotective effect of combined SW and AG (SWA-1) treatment and the underlying molecular mechanism by which SWA-1 regulates neurodegenerative diseases remains unclear. We evaluated the neuroprotective effect of SWA-1 against Sco-induced mild cognitive impairment in mice and H₂O₂-induced cell death in HT22 mouse hippocampal neuronal cells and elucidated the underlying molecular mechanism. Morris water maze and Y-maze tests were performed to examine the learning and memory abilities of mice. The underlying molecular mechanism was investigated by using western blotting. We demonstrated that SWA-1 significantly protects against H₂O₂-induced cell death in HT22 mouse hippocampal neuronal cells. SWA-1 also significantly reversed Sco-induced spatial learning and memory impairment. Specifically, SWA-1 upregulates the protein levels of phosphorylated extracellular signal-related kinase (Erk1/2) and phosphorylated p38 MAP kinase (p38). SWA-1 remarkably decreased the apoptotic index Bax/Bcl2 expression in the hippocampus of Sco-treated mice. Our results suggest that SWA-1 may be administered as alternative therapy for cognitive impairment and neurodegenerative diseases and should be studied further in human trials.

Autophagy Modulators Profoundly Alter the Astrocyte Cellular Proteome

Autophagy is a key cellular process that involves constituent degradation and recycling during cellular development and homeostasis. Autophagy also plays key roles in antimicrobial host defense and numerous pathogenic organisms have developed strategies to take advantage of and/or modulate cellular autophagy. Several pharmacologic compounds, such as BafilomycinA1, an autophagy inducer, and Rapamycin, an autophagy inhibitor, have been used to modulate autophagy, and their effects upon notable autophagy markers, such as LC3 protein lipidation and Sequestosome-1/p62 alterations are well defined. We sought to understand whether such autophagy modulators have a more global effect upon host cells and used a recently developed aptamer-based proteomic platform (SOMAscan^®) to examine 1305 U-251 astrocytic cell proteins after the cells were treated with each compound. These analyses, and complementary cytokine array analyses of culture supernatants after drug treatment, revealed substantial perturbations in the U-251 astrocyte cellular proteome. Several proteins, including cathepsins, which have a role in autophagy, were differentially dysregulated by the two drugs as might be expected. Many proteins, not previously known to be involved in autophagy, were significantly dysregulated by the compounds, and several, including lactadherin and granulins, were up-regulated by both drugs. These data indicate that these two compounds, routinely used to help dissect cellular autophagy, have much more profound effects upon cellular proteins.

Oxiracetam ameliorates cognitive deficits in vascular dementia rats by regulating the expression of neuronal apoptosis/autophagy-related genes associated with the activation of the Akt/mTOR signaling pathway

Oxiracetam (ORC) is a commonly used nootropic drug for improving cognition and memory impairments. The therapeutic effect and underlying mechanism of ORC in vascular dementia (VaD) treatment remain unknown. In this study, 3-month-old male Sprague-Dawley rats with permanent bilateral common carotid artery occlusion-induced VaD were treated orally with low (100 mg/kg) or high (200 mg/kg) dose ORC once a day for 4 weeks. The results of the Morris water maze test and Nissl staining showed that ORC treatment significantly alleviated learning and memory deficits and neuronal damage in rats with VaD. Mechanistically, the protein levels of a panel of genes associated with neuronal apoptosis (Bcl-2, Bax) and autophagy (microtubule-associated protein 1 chain 3, Beclin1, p62) were significantly altered by ORC treatment compared with VaD, suggesting a protective role of ORC against VaD-induced neuronal apoptosis and autophagy. Moreover, the Akt/mTOR pathway, which is known to be the upstream signaling governing apoptosis and autophagy, was found to be activated in ORC-treated rats, suggesting an involvement of Akt/mTOR activation in ORC-rendered protection in VaD rats. Taken together, this study demonstrated that ORC may alleviate learning and memory impairments and neuronal damage in VaD rats by altering the expression of apoptosis/autophagy-related genes and activation of the Akt/mTOR signaling pathway in neurons.

Studies on the Neuroprotection of Osthole on Glutamate-Induced Apoptotic Cells and an Alzheimer's Disease Mouse Model via Modulation Oxidative Stress

In the present study, the neuroprotection of osthole (OST) was confirmed. In L-glutamic acid (L-Glu)-damaged HT22 cells, a 3-h pre-incubation with OST-enhanced cell viability suppressed the apoptosis rate; inhibited the activities of caspase-3, caspase-8, and caspase-9; reduced the over-accumulation of intracellular reactive oxygen species; restored the dissipated mitochondrial membrane potential; and regulated the expression levels of B cell lymphoma-2 (Bcl-2), Bax, cleaved poly (ADP-ribose) polymerase (PARP), NF-E2p45-related factor 2 (Nrf2), and its downstream proteins. In amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice, an 8-week OST administration improved the pathological behaviors related to memory and cognition, and reduced the expression levels of 4-hydroxynonenal, the deposition of β-amyloid peptides and neuronal fiber tangles formed by the high phosphor-Tau in the brain. OST enhanced the expression levels of Nrf2 and its downstream proteins including superoxide dismutase-1 (SOD-1) and heme oxygenase-1 (HO-1). The present data confirmed the protection of OST against AD-like symptoms via modulating oxidative stress, especially Nrf2 signaling.

Inonotus obliquus polysaccharides protect against Alzheimer's disease by regulating Nrf2 signaling and exerting antioxidative and antiapoptotic effects

Inonotus obliquus polysaccharide (IOPS) was initially separated and purified via precipitation from an aqueous extract with 80% alcohol, a DEAE-52 cellulose anion exchange column, and a Sephadex G-100 gel permeation chromatography system. IOPS was found to have a molecular weight of 111.9 kDa. In L-glutamic acid (L-Glu)-damaged HT22 cells, a 3-h pre-incubation with IOPS enhanced cell viability, inhibited apoptosis and caspase-3 activity, reduced the release of lactate dehydrogenase, restored the dissipated mitochondrial membrane potential, and suppressed the excess accumulation of intracellular reactive oxygen species. Compared with L-Glu-exposed cells, IOPS pre-treated cells exhibited reduced levels of Bcl-2 associated X protein (Bax) and Kelch-like ECH-associated protein 1 (Keap1) and enhanced levels of B-cell lymphoma-2 (Bcl-2), NF-E2p45-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), superoxide dismutase-1 (SOD-1), and cysteine ligase catalytic subunit. In amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice, an 8-week course of IOPS improved the pathological behaviors related to memory and cognition, reduced the deposition of β-amyloid peptides and neuronal fiber tangles induced by enhanced phosphor-Tau in the brain, and modulated the levels of anti- and pro-oxidative stress enzymes. Additionally, IOPS enhanced the expression levels of Nrf2 and its downstream proteins, including HO-1 and SOD-1, in the brains of APP/PS1 mice. The present study successfully demonstrated the protective effect of IOPS against AD and revealed the possible mechanism underlying the ability of IOPS to modulate oxidative stress, especially Nrf2 signaling, and mediate mitochondrial apoptosis.

Protective roles of isoastilbin against Alzheimer's disease via Nrf2‑mediated antioxidation and anti‑apoptosis

By analyzing the L‑glutamic acid (L‑Glu)‑induced apoptosis of PC12 cells and an AlCl3 combined with D‑galactose (D‑gal)‑developed Alzheimer's disease (AD) mouse model, the protective effects of isoastilbin (IAB) against AD were systematically investigated in the present study. Pre‑incubation with IAB for 3 h prior to treatment with 25 mM L‑Glu decreased cell viability and inhibited apoptosis, suppressed the accumulation of intracellular reactive oxygen species, and restored mitochondrial membrane potential in PC12 cells induced by L‑Glu. In mice with AD, the reduced escape latency time in the water maze test, suppressed chronic movement in the center area of an open field test and enhanced ability to seek hidden food in a Y maze test indicated that abnormal behaviors had improved after 28 days of treatment with IAB. Furthermore, IAB reduced the deposition of amyloid β (Aβ) and the expression of phosphorylated‑Tau in the mouse brain and enhanced the serum levels of Aβ. IAB ameliorated the oxidative stress via modulating the levels of associated enzymes and improved the functioning of the central cholinergic system, as indicated by an increase in acetylcholine and choline acetyltransferase concentrations. The expression levels of acetylcholine esterase were reduced in the mouse brain in response to IAB pre‑treatment. In cells and brain tissue, IAB regulated the expression levels of pro‑ and anti‑apoptotic proteins and enhanced the nuclear levels of NF‑E2p45‑related factor 2 (Nrf2); subsequently, IAB further enhanced the expression of superoxide dismutase 1, catalase, and heme oxygenase‑1 and ‑2. The findings of the present study indicated that the protection of IAB against AD is at least partially associated with its antioxidation and anti‑apoptotic properties.

A Flow Cytometric Study of ER Stress and Autophagy

The mechanistic link between ER stress, autophagy, and resultant cell death was investigated by the use of drugs Thapsigargin (Tg) and Chloroquine (CQ) with prior induction and or blockade of autophagy and apoptosis which modulated the ER stress response and resultant form of cell death. All these biological processes can be measured flow cytometrically allowing the determination of the type of cell death, G₁ cell cycle arrest, cell cycle dependent measurement of ER stress transducer PERK, misfolded proteins, reticulophagy, and autophagy marker LC3B. Jurkat cells after Tg or CQ treatment became necrotic and apoptotic, showed G₁ cell cycle arrest, autophagy, and ER stress. Prior induction of autophagy before ER stress increased levels of necrotic and apoptotic cell death. Autophagy was further up-regulated, while PERK was reduced or abrogated. CQ showed reduced levels of misfolded proteins and reticulophagy, while Tg showed no change in misfolded protein levels but increased reticulophagy and thus displayed more ER stress. Prior blockade of apoptosis before induction of ER stress resulted in cell survival except with high Tg levels which induced necrosis. Autophagy was up-regulated with modulation of PERK and reticulophagy levels with an abrogation of the misfolded protein response. Blockade of apoptosis with induction of autophagy before ER stress showed death by necrosis with high dose drugs and cell survival with low doses of drugs. CQ induced reduced levels G₁ cell cycle arrest while it was maintained with Tg. Autophagy was also maintained with reduced levels of ER stress. These data demonstrates a profound link between the processes of ER stress, autophagy, and the resultant form of cell death all of which can be modulated depending upon the sequence and concentration of drugs employed. © 2018 International Society for Advancement of Cytometry.

Walnut ( Juglans regia) Peptides Reverse Sleep Deprivation-Induced Memory Impairment in Rat via Alleviating Oxidative Stress

The aim of this study was to determine the neuroprotective effects of walnut protein hydrolysates (WPH) against memory deficits induced by sleep deprivation (SD) in rat and further to identify and characterize the potent neuroprotective peptides against glutamate-induced apoptosis in PC12 cells. Results showed that a remarkable amelioration effect on behavioral performance in Morris water maze test was observed for WPH and its low molecular weight fraction WPHL, especially for WPHL. Additionally, a reduction of antioxidant defense (catalase, glutathione peroxidase (GSH-px), and superoxide dismutase (SOD)) and an increase of malondialdehyde content induced by SD were normalized in brain of rat after oral administration of WPH and WPHL. Then three neuroprotective peptides including GGW, VYY, and LLPF were identified from WPHL, which could protect PC12 cells against glutamate-induced apoptosis with relative cell viability of 78.29 ± 3.09%, 80.65 ± 1.74%, and 83.97 ± 3.06%, respectively, versus glutamate group 48.61 ± 3.99%. The possible mechanism underlying their protective effects of GGW and VYY could be related to their strong radical scavenging activity as well as their ability to reduce reactive oxygen species production and the depletion of SOD and GSH-px in PC12 cells. Notably, the marked neuroprotective effects of LLPF, which did not show obvious free-radical scavenging activity in vitro, could be attributed to its strong effects on inhibiting Ca²⁺ influx and mitochondrial membrane potential collapse. Additionally, all these peptides could regulate the expression of apoptosis-related proteins (Bax and Bcl-2). Therefore, walnut peptides might be regarded as the potential nutraceuticals against neurodegenerative disorders associated with memory deficits.

Pharmacological basis for application of scutellarin in Alzheimer's disease: Antioxidation and antiapoptosis

Scutellarin (SC), mainly extracted from the Chinese herb Erigeron breviscapus (vant.), has been reported to possess various pharmacological activities; however, its effects on Alzheimer's disease (AD) have not been systemically reported. The protective effects of SC on AD were investigated using an L‑glutamic acid (L‑Glu)‑damaged HT22 cell apoptosis model and an aluminum chloride plus D‑galactose‑induced AD mouse model. In L‑Glu‑damaged HT22 cells, SC significantly increased cell viability, inhibited lactate dehydrogenase release, reduced caspase‑3 activity and suppressed apoptosis, which were determined via an MTT assay, an in vitro Toxicology Assay kit, a Caspase‑3 activity assay kit, and propidium iodide and Annexin V staining. Furthermore, SC suppressed the accumulation of intracellular reactive oxygen species (ROS), restored the dissipation of mitochondrial membrane potential, enhanced the expression of antiapoptotic proteins and reduced the expression of pro‑apoptotic proteins, as determined by immunofluorescence assays and western blotting. In AD mice, SC enhanced vertical and horizontal movements in an autonomic activity test, and reduced the escape latency time in the water maze test. SC reduced the deposition of amyloid β1‑42 (Aβ1‑42) and the expression of phosphorylated‑Tau in the hippocampus as determined by immunohistochemistry analysis, but enhanced the serum levels of Aβ1‑42 of AD mice as determined by ELISA. ELISA analyses also revealed that SC enhanced the levels of acetylcholine, and superoxide dismutase in serum and brain lysate, whereas reduced the levels of ROS in brain lysate of AD mice. The present study confirmed that the protective effects of SC in AD in vitro and in vivo are associated with its antioxidant and antiapoptotic properties.

Pathophysiological Roles of Intracellular Proteases in Neuronal Development and Neurological Diseases

Proteases are classified into six distinct classes (cysteine, serine, threonine, aspartic, glutamic, and metalloproteases) on the basis of catalytic mechanism. The cellular control of protein quality senses misfolded or damaged proteins principally by selective ubiquitin-proteasome pathway and non-selective autophagy-lysosome pathway. The two pathways do not only maintain cell homeostasis physiologically, but also mediate necrosis and apoptosis pathologically. Proteasomes are threonine proteases, whereas cathepsins are lysosomal aspartic proteases. Calpains are non-lysosomal cysteine proteases and calcium-dependent papain-like enzyme. Calpains and cathepsins are involved in the neuronal necrosis, which are accidental cell death. Necrosis is featured by the disruption of plasma membranes and lysosomes, the loss of ATP and ribosomes, the lysis of cell and nucleus, and the caspase-independent DNA fragmentation. On the other hand, caspases are cysteine endoproteases and mediate neuronal cell death such as apoptosis and pyroptosis, which are programmed cell death. In the central nervous system, necroptosis, ferroptosis and autophagic cell death are also classified into programmed cell death. Neuronal apoptosis is characterized by cell shrinkage, plasma membrane blebbing, karyorrhexis, chromatin condensation, and DNA fragmentation. Necroptosis and pyroptosis are necrotic and lytic forms of programmed cell death, respectively. Although autophagy is involved in cell survival, it fails to maintain cellular homeostasis, resulting in autophagic cell death. Ferroptosis is induced by reactive oxygen species in excitotoxicity of glutamate and ischemia-reperfusion. Apoptosis and pyroptosis are dependent on caspase-3 and caspase-1, respectively. Autophagic cell death and necroptosis are dependent on calpain and cathepsin, respectively, but independent of caspase. Although apoptosis has been defined by the absence of morphological features of necrosis, the two deaths are both parts of a continuum. The intracellular proteases do not only maintain cell homeostasis but also regulate neuronal maturation during the development of embryonic brain. Furthermore, neurodegenerative diseases are caused by the impairment of quality control mechanisms for a proper folding and function of protein.

Systemic inflammation induced by lipopolysaccharide aggravates inherited retinal dystrophy

Retinal neurodegenerative diseases involve a scenario of inflammation and cell death that leads to morphological alterations and visual impairment. Non-ocular inflammatory processes could affect neurodegenerative retinal disorders and their progression, at least in part by activating microglial cells and releasing pro-inflammatory cytokines. Our purpose was to study the consequences of a systemic inflammatory process in the progression of retinal degeneration in P23H rats, a retinitis pigmentosa (RP) model. In order to induce a mild chronic systemic inflammation, we administered low doses of lipopolysaccharide (LPS) from age P20 to P60 to dystrophic P23H rats and healthy SD rats. Visual responsiveness was assessed by electroretinography (ERG). The morphological state of the retinas was analyzed by fluorescent immunohistochemistry (IHC), evaluating the number, morphology, and connectivity of different neuronal populations by means of cell type-specific markers. Microglia density, distribution, and degree of activation were evaluated by IHC and flow cytometry. The expression levels of inflammation- and apoptosis-related genes were analyzed by qRT-PCR arrays. Low-dose LPS administration did not induce significant functional or morphological changes in the retina of SD rats, although at the molecular level, we detected expression changes in genes related to apoptosis. Otherwise, systemic injection of LPS into P23H rats induced a further deterioration in the ERG response, with greater loss of photoreceptors and worsening of synaptic connectivity, accompanied by increasing numbers of microglial cells, which also showed a more intense activation state. Several inflammation- and apoptosis-related genes were upregulated. Our results indicate that chronic exacerbation of the inflammatory response in response to LPS accelerates neurodegeneration in dystrophic P23H rats, suggesting that in patients with ocular neurodegenerative diseases, peripheral damage, as a systemic infection or chronic inflammatory process, could accelerate disease progression, and should be taken into account in order to select an appropriate therapy to revert, block or slow-down the degenerative process.

Neuroprotective Effects of Acetylcholinesterase Inhibitory Peptides from Anchovy (Coilia mystus) against Glutamate-Induced Toxicity in PC12 Cells

Ameliorations of cholinergic system dysfunction and oxidative stress in neurodegenerative diseases were main approaches to improve memory disorder. Our previous investigation showed that anchovy protein hydrolysate (APH) could attenuate scopolamine-induced memory deficits in mice by regulating acetylcholinesterase (AChE) activity. Therefore, peptides with AChE inhibitory activity in APH were explored and identified in this study, and their possible neuroprotective mechanisms on glutamate induced apoptosis in PC12 were also elucidated. Two peptides with strong AChE inhibitory capacity were identified as Pro-Ala-Tyr-Cys-Ser (PAYCS) and Cys-Val-Gly-Ser-Tyr (CVGSY) by ultraperformance liquid chromatography coupled with tandem mass spectrometry. The AChE inhibitory was 23.68 ± 0.97% and 6.08 ± 0.41%, respectively. Treatment with PAYCS and CVGSY could significantly (p < 0.05) increase cells viability, reduce lactate dehydrogenase release, reactive oxygen species (ROS) production, malondialdehyde content, and the ratio of Bax/Bcl-2 of glutamate-induced apoptosis PC12 cells (82.78 ± 6.58 and 109.94 ± 7.16% of control, respectively) as well as increase superoxide dismutase and GSH-px activities. In addition, both the peptides could inhibit Ca²⁺ influx but have no effects on mitochondrial membrane potential. Results indicated that AChE inhibitory peptides (PAYCS and CVGSY) possibly protected the PC12 cells against glutamate-induced apoptosis via inhibiting ROS production and Ca²⁺ influx. PAYCS and CVGSY might be considered as nutraceuticals for alleviating memory deficits.

Investigation of the neuroprotective effects of Lycium barbarum water extract in apoptotic cells and Alzheimer's disease mice

Alzheimer's disease (AD) affects people worldwide and is caused by chronic and progressive damage to the central nervous system. Lycium barbarum (LB), a renowned functional food and medicinal plant in Southeast Asia, may possess protective effects against nerve injury. The present study aimed to investigate the neuroprotective effects of LB water extract in a differentiated (D)PC12 cellular apoptosis model induced by L-glutamic acid (L-Glu), and a mouse model of AD, induced by the combination of AlCl₃ and D-galactose. LB markedly increased DPC12 cell survival against L-Glu induced damage by increasing cell viability, reducing the apoptosis rate and G1 phase arrest, suppressing intracellular reactive oxygen species accumulation, blocking Ca²⁺ overload and preventing mitochondrial membrane potential depolarization. LB additionally normalized the expression levels of apoptosis regulator Bcl-2, apoptosis regulator BAX, and cleaved caspase-3, −8 and −9 in L-Glu exposed cells. In the AD mouse model, LB increased the amount of horizontal and vertical movement in the autonomic activity test, improved endurance time in the rotarod test and decreased escape latency time in the Morris water maze test. Additionally, the levels of acetylcholine and choline acetyltransferase were significantly increased in the serum and hypothalamus in the LB-treated AD mice. These data suggested that LB may exert neuroprotective effects and may aid in preventing neurodegenerative disease.

Anti-Oxidative Stress Activity Is Essential for Amanita caesarea Mediated Neuroprotection on Glutamate-Induced Apoptotic HT22 Cells and an Alzheimer's Disease Mouse Model

Amanita caesarea, an edible mushroom found mainly in Asia and southern Europe, has been reported to show good antioxidative activities. In the present study, the neuroprotective effects of A. caesarea aqueous extract (AC) were determined in an l-glutamic acid (l-Glu) induced HT22 cell apoptosis model, and in a d-galactose (d-gal) and AlCl₃-developed experimental Alzheimer’s disease (AD) mouse model. In 25 mM of l-Glu-damaged HT22 cells, a 3-h pretreatment with AC strongly improved cell viability, reduced the proportion of apoptotic cells, restored mitochondrial function, inhibited the over-production of intracellular reactive oxygen species (ROS) and Ca²⁺, and suppressed the high expression levels of cleaved-caspase-3, calpain 1, apoptosis-inducing factor (AIF) and Bax. Compared with HT22 exposed only to l-Glu cells, AC enhanced the phosphorylation activities of protein kinase B (Akt) and the mammalian target of rapamycin (mTOR), and suppressed the phosphorylation activities of phosphatase and tensin homolog deleted on chromosome ten (PTEN). In the experimental AD mouse, 28-day AC administration at doses of 250, 500, and 1000 mg/kg/day strongly enhanced vertical movements and locomotor activities, increased the endurance time in the rotarod test, and decreased the escape latency time in the Morris water maze test. AC also alleviated the deposition of amyloid beta (Aβ) in the brain and improved the central cholinergic system function, as indicated by an increase acetylcholine (Ach) and choline acetyltransferase (ChAT) concentrations and a reduction in acetylcholine esterase (AchE) levels. Moreover, AC reduced ROS levels and enhanced superoxide dismutase (SOD) levels in the brain of experimental AD mice. Taken together, our data provide experimental evidence that A. caesarea may serve as potential food for treating or preventing neurodegenerative diseases.

Autophagy down regulates pro-inflammatory mediators in BV2 microglial cells and rescues both LPS and alpha-synuclein induced neuronal cell death

Autophagy is a fundamental cellular homeostatic mechanism, whereby cells autodigest parts of their cytoplasm for removal or turnover. Neurodegenerative disorders are associated with autophagy dysregulation, and drugs modulating autophagy have been successful in several animal models. Microglial cells are phagocytes in the central nervous system (CNS) that become activated in pathological conditions and determine the fate of other neural cells. Here, we studied the effects of autophagy on the production of pro-inflammatory molecules in microglial cells and their effects on neuronal cells. We observed that both trehalose and rapamycin activate autophagy in BV2 microglial cells and down-regulate the production of pro-inflammatory cytokines and nitric oxide (NO), in response to LPS and alpha-synuclein. Autophagy also modulated the phosphorylation of p38 and ERK1/2 MAPKs in BV2 cells, which was required for NO production. These actions of autophagy modified the impact of microglial activation on neuronal cells, leading to suppression of neurotoxicity. Our results demonstrate a novel role for autophagy in the regulation of microglial cell activation and pro-inflammatory molecule secretion, which may be important for the control of inflammatory responses in the CNS and neurotoxicity.

Role of hypoxia‑inducible factor‑1α in autophagic cell death in microglial cells induced by hypoxia

Microglial cells are phagocytic cells of the central nervous system (CNS) and have been proposed to be a primary component of the innate immune response and maintain efficient CNS homeostasis. Microglial cells are activated during various phases of tissue repair and participate in various pathological conditions in the CNS. Following spinal cord injury (SCI), anoxemia is a key problem that results in tissue destruction. Hypoxia-inducible factor 1-α (HIF-1α) may protect hypoxic cells from apoptosis or necrosis under ischemic and anoxic conditions. However, numerous studies have revealed that hypoxia upregulates HIF-1α expression leading to the death of microglial cells. The present study investigated the alterations in HIF-1α expression levels and the mechanism of autophagic cell death mediated by HIF-1α in microglial cells induced by hypoxia. Hypoxia was demonstrated to induce HIF-1α expression and autophagic cell death in microglial cells. Enhanced autophagy reduced cell death during the initial stages by restraining the functions of autophagy-associated genes (microtubule-associated protein 1A/1B-light chain 3 phosphatidylethanolamine conjugate and Beclin-1) and modulating the expression of inflammatory cytokines (tumor necrosis factor-α and interleukin-1β). Target value was determined by Cell Counting Kit 8 and cell death by flow cytometry. Transmission electron microscopy, immunohistochemical staining, reverse transcription-quantitative polymerase chain reaction, western blotting, and ELISA were used for further analysis. However, increased expression of HIF-1α induced cell death and autophagic cell death in microglial cells. Furthermore, the effects of the HIF-1α inhibitor 2-methoxyestradiol and HIF-1α small interfering RNA on the death and autophagy of microglial cells in vitro were investigated. These investigations revealed the suppression of autophagy, the decrease of cell viability and the increase of inflammatory cytokines results from HIF-1α inhibition or HIF-1α silencing. In conclusion, the results indicated that appropriate expression of HIF-1α can ameliorate autophagic cell death of microglial cells associated with hypoxia, and may provide a novel therapeutic approach for SCI associated with microglial cell activation.

Vitamin-D Deficiency As a Potential Environmental Risk Factor in Multiple Sclerosis, Schizophrenia, and Autism

In this short review, we want to summarize the current findings on the role of vitamin-D in multiple sclerosis (MS), schizophrenia, and autism. Many studies have highlighted hypovitaminosis-D as a potential environmental risk factor for a variety of conditions such as MS, asthma, cardiovascular disease, and, more recently, psychiatric diseases. However, whether hypovitaminosis-D is a potential causative factor for the development or activity in these conditions or whether hypovitaminosis-D may be due to increased vitamin-D consumption by an activated immune system (reverse causation) is the focus of intense research. Here, we will discuss current evidence exploring the role of vitamin-D in MS, schizophrenia, and autism and its impact on adaptive and innate immunity, antimicrobial defense, the microbiome, neuroinflammation, behavior, and neurogenesis. More work is needed to gain insight into its role in the underlying pathophysiology of these conditions as it may offer attractive means of intervention and prevention.

The Neuroprotective Properties of Hericium erinaceus in Glutamate-Damaged Differentiated PC12 Cells and an Alzheimer's Disease Mouse Model

Hericium erinaceus, an edible and medicinal mushroom, displays various pharmacological activities in the prevention of dementia in conditions such as Parkinson's and Alzheimer's disease. The present study explored the neuroprotective effects of H. erinaceus mycelium polysaccharide-enriched aqueous extract (HE) on an l-glutamic acid (l-Glu)-induced differentiated PC12 (DPC12) cellular apoptosis model and an AlCl₃ combined with d-galactose-induced Alzheimer's disease mouse model. The data revealed that HE successfully induced PC12 cell differentiation. A 3 h HE incubation at doses of 50 and 100 µg/mL before 25 mM of l-Glu effectively reversed the reduction of cell viability and the enhancement of the nuclear apoptosis rate in DPC12 cells. Compared with l-Glu-damaged cells, in PC12 cells, HE suppressed intracellular reactive oxygen species accumulation, blocked Ca2+ overload and prevented mitochondrial membrane potential (MMP) depolarization. In the Alzheimer's disease mouse model, HE administration enhanced the horizontal and vertical movements in the autonomic activity test, improved the endurance time in the rotarod test, and decreased the escape latency time in the water maze test. It also improved the central cholinergic system function in the Alzheimer's mice, demonstrated by the fact that it dose-dependently enhanced the acetylcholine (Ach) and choline acetyltransferase (ChAT) concentrations in both the serum and the hypothalamus. Our findings provide experimental evidence that HE may provide neuroprotective candidates for treating or preventing neurodegenerative diseases.

EVA1A/TMEM166 Regulates Embryonic Neurogenesis by Autophagy

Self-renewal and differentiation of neural stem cells is essential for embryonic neurogenesis, which is associated with cell autophagy. However, the mechanism by which autophagy regulates neurogenesis remains undefined. Here, we show that Eva1a/Tmem166, an autophagy-related gene, regulates neural stem cell self-renewal and differentiation. Eva1a depletion impaired the generation of newborn neurons, both in vivo and in vitro. Conversely, overexpression of EVA1A enhanced newborn neuron generation and maturation. Moreover, Eva1a depletion activated the PIK3CA-AKT axis, leading to the activation of the mammalian target of rapamycin and the subsequent inhibition of autophagy. Furthermore, addition of methylpyruvate to the culture during neural stem cell differentiation rescued the defective embryonic neurogenesis induced by Eva1a depletion, suggesting that energy availability is a significant factor in embryonic neurogenesis. Collectively, these data demonstrated that EVA1A regulates embryonic neurogenesis by modulating autophagy. Our results have potential implications for understanding the pathogenesis of neurodevelopmental disorders caused by autophagy dysregulation.

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EVA1A is elevated during embryonic neurogenesis with enhanced autophagy activation

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EVA1A deletion results in defective self-renewal and differentiation of NSCs

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EVA1A modulates autophagy through the PIK3CA/AKT-mTOR pathway

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Methylpyruvate, perifosine, and rapamycine restore neurogenesis in Eva1a^−/− NSCs

Mitochondria Related Pathway Is Essential for Polysaccharides Purified from Sparassis crispa Mediated Neuro-Protection against Glutamate-Induced Toxicity in Differentiated PC12 Cells

The present study aims to explore the neuro-protective effects of purified Sparassis crispa polysaccharides against l-glutamic acid (l-Glu)-induced differentiated PC12 (DPC12) cell damages and its underlying mechanisms. The Sparassis crispa water extract was purified by a DEAE-52 cellulose anion exchange column and a Sepharose G-100 column. A fraction with a molecular weight of 75 kDa and a diameter of 88.9 nm, entitled SCWEA, was obtained. SCWEA was identified with a triple helix with (1→3)-linked Rha in the backbone, and (1→2) linkages and (1→6) linkages in the side bone. Our results indicated that the pre-treatment of DPC12 cells with SCWEA prior to l-Glu exposure effectively reversed the reduction on cell viability (by 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay) and reduced l-Glu-induced apoptosis (by Hoechst staining). SCWEA decreased the accumulation of intracellular reactive oxygen species, blocked Ca²⁺ influx and prevented depolarization of the mitochondrial membrane potential in DPC12 cells. Furthermore, SCWEA normalized expression of anti-apoptotic proteins in l-Glu-explored DPC12 cells. These results suggested that SCWEA protects against l-Glu-induced neuronal apoptosis in DPC12 cells and may be a promising candidate for treatment against neurodegenerative disease.

Autophagy-related gene 5 and Wnt5 signaling pathway requires differentiation of embryonic stem cells into odontoblast-like cells

We previously confirmed a unique and unanticipated role for an α2 integrin, extracellular matrix metalloproteinase inducer (Emmprin), and matrix metalloproteinase (MMP)-3-mediated signaling cascade, in driving the odontoblast-like differentiation of mouse embryonic stem (ES) cells in a collagen type-I scaffold (CS) combined with bone morphogenetic protein (BMP)-4 (CS/BMP-4). To explore the early signaling cascade for odontoblastic differentiation, we examined the upregulation of autophagy-related gene (Atg) and Wnt signaling by CS/BMP-4 mediated odontoblast differentiation. In a screening experiment, CS/BMP-4 increased the mRNA and protein levels of Atg5, Lrp5/Fzd9 (an Atg5 receptor), and Wnt5, but not microtubule-associated protein 1 light chain (LC3; a mammalian homolog of yeast Atg8), TFE3, Beclin1, and Atg12, together with the amount of autophagosomes and autophagy fluxes. Treatment with siRNAs against Atg5 and Wnt5 individually suppressed the CS/BMP-4-induced increase in odontoblast differentiation. The odontoblastic phenotype, involving dentin matrix protein-1 and dentin sialophosphoprotein expression, decreased when autophagy was inhibited by chloroquine, but increased after treatment with rapamycin (an autophagy enhancer). Taken together with our previous findings, we have revealed a unique sequential cascade involving Atg5, Wnt5a, α2 integrin, Emmprin, and MMP-3. This cascade results in a potent increase in odontoblastic cell differentiation, indicating the unique involvement of Atg5, autophagy and Wnt5 signaling in CS/BMP-4-induced differentiation of ES cells into odontoblast-like cells, at a relatively early stage.

miR-Let7A Modulates Autophagy Induction in LPS-Activated Microglia

Microglia regulate the secretion of various immunomediators in central nervous system diseases. Microglial autophagy is the crucial process for cell's survival and cytokine productions. Recent studies have reported that several microRNAs are involved in the autophagy system. miR-Let7A is such a microRNA that plays a role in various inflammation responses, and is magnified as a key modulator particularly in the autophagy system. In present study, we investigated whether miR-Let7A is involved in autophagy in activating microglia. Overexpression of miR-Let7A in LPS-stimulated BV2 microglial cells promoted the induction of the autophagy related factors such as LC3II, Beclin1, and ATG3. Our results suggest a potential role of miR-Let7A in the autophagy process of microglia during CNS inflammation.

Interleukin-1β-induced autophagy-related gene 5 regulates proliferation of embryonic stem cell-derived odontoblastic cells

We previously established a method for the differentiation of induced pluripotent stem cells and embryonic stem cells into α2 integrin-positive odontoblast-like cells. We also reported that Wnt5 in response to interleukin (IL)-1β induces matrix metalloproteinase (MMP)-3-regulated cell proliferation in these cells. Our findings suggest that MMP-3 plays a potentially unique physiological role in the generation of odontoblast-like cells under an inflammatory state. Here, we examined whether up-regulation of autophagy-related gene (Atg) 5 by IL-1β was mediated by Wnt5 signaling, thus leading to increased proliferation of odontoblast-like cells. IL-1β increased the mRNA and protein levels of Atg5, microtubule-associated protein 1 light chain (LC3, a mammalian homolog of yeast Atg8) and Atg12. Treatment with siRNAs against Atg5, but not LC3 and Atg12, suppressed the IL-1β-induced increase in MMP-3 expression and cell proliferation. Our siRNA analyses combined with western blot analysis revealed a unique sequential cascade involving Atg5, Wnt5a and MMP-3, which resulted in the potent increase in odontoblastic cell proliferation. These results demonstrate the unique involvement of Atg5 in IL-1β-induced proliferation of embryonic stem cell-derived odontoblast-like cells.

Neuronal cell death: an overview of its different forms in central and peripheral neurons

The discovery of neuronal cell death dates back to the nineteenth century. Nowadays, after a very long period of conceptual difficulties, the notion that cell death is a phenomenon occurring during the entire life course of the nervous system, from neurogenesis to adulthood and senescence, is fully established. The dichotomy between apoptosis, as the prototype of programmed cell death (PCD ), and necrosis, as the prototype of death caused by an external insult, must be carefully reconsidered, as different types of PCD: apoptosis, autophagy, pyroptosis, and oncosis have all been demonstrated in neurons (and glia ). These modes of PCD may be triggered by different stimuli, but share some intracellular pathways such that different types of cell death may affect the same population of neurons according to several intrinsic and extrinsic factors. Therefore, a mixed morphology is often observed also depending on degrees of differentiation, activity, and injury. The main histological and ultrastructural features of the different types of cell death in neurons are described and related to the cellular pathways that are specifically activated in any of these types of PCD.

Complex network-driven view of genomic mechanisms underlying Parkinson's disease: analyses in dorsal motor vagal nucleus, locus coeruleus, and substantia nigra

Parkinson's disease (PD)—classically characterized by severe loss of dopaminergic neurons in the substantia nigra pars compacta—has a caudal-rostral progression, beginning in the dorsal motor vagal nucleus and, in a less extent, in the olfactory system, progressing to the midbrain and eventually to the basal forebrain and the neocortex. About 90% of the cases are idiopathic. To study the molecular mechanisms involved in idiopathic PD we conducted a comparative study of transcriptional interaction networks in the dorsal motor vagal nucleus (VA), locus coeruleus (LC), and substantia nigra (SN) of idiopathic PD in Braak stages 4-5 (PD) and disease-free controls (CT) using postmortem samples. Gene coexpression networks (GCNs) for each brain region (patients and controls) were obtained to identify highly connected relevant genes (hubs) and densely interconnected gene sets (modules). GCN analyses showed differences in topology and module composition between CT and PD networks for each anatomic region. In CT networks, VA, LC, and SN hub modules are predominantly associated with neuroprotection and homeostasis in the ageing brain, whereas in the patient's group, for the three brain regions, hub modules are mostly related to stress response and neuron survival/degeneration mechanisms.

The crucial role of Atg5 in cortical neurogenesis during early brain development

Autophagy plays an important role in the central nervous system. However, it is unknown how autophagy regulates cortical neurogenesis during early brain development. Here, we report that autophagy-related gene 5 (Atg5) expression increased with cortical development and differentiation. The suppression of Atg5 expression by knockdown led to inhibited differentiation and increased proliferation of cortical neural progenitor cells (NPCs). Additionally, Atg5 suppression impaired cortical neuronal cell morphology. We lastly observed that Atg5 was involved in the regulation of the β-Catenin signaling pathway. The β-Catenin phosphorylation level decreased when Atg5 was blocked. Atg5 cooperated with β-Catenin to modulate cortical NPCs differentiation and proliferation. Our results revealed that Atg5 has a crucial role in cortical neurogenesis during early embryonic brain development, which may contribute to the understanding of neurodevelopmental disorders caused by autophagy dysregulation.

Tumor necrosis factor receptor-associated periodic syndrome as a model linking autophagy and inflammation in protein aggregation diseases

Autophagy prevents cellular damage by eliminating insoluble aggregates of mutant misfolded proteins, which accumulate under different pathological conditions. Downregulation of autophagy enhances the inflammatory response and thus represents a possible common pathogenic event underlying a number of autoinflammatory syndromes, such as tumor necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS). The pathogenesis of other monogenic or complex disorders that display symptoms of excessive inflammation also involve the autophagy pathway. Studies have shown that TRAPS-associated TNFRSF1A mutations induce cytoplasmic retention of the TNFR1 receptor, defective TNF-induced apoptosis, and production of reactive oxygen species (ROS). Furthermore, autophagy impairment may account for the pathogenic effects of TNFRSF1A mutations, thus inducing inflammation in TRAPS. In this review, we summarize the molecular interactions and functional links between autophagy with regard to nuclear factor-kappa B activation, ROS production, and apoptosis. Furthermore, we propose a complex interplay of these pathways as a model to explain the relationship between mutant protein misfolding and inflammation in genetically determined and aggregation-prone diseases. Accordingly, autophagy function should be investigated in all diseases showing an inflammatory component, and for which the molecular pathogenesis is still unclear.

Measurement of autophagy by flow cytometry

In recent years, flow cytometry has been used to detect the presence of autophagy mainly by the fluorescent antibody labeling of the autophagy marker, the microtubule associated protein LC3-II. Here we describe the indirect antibody labeling of LC3-II in cells displaying drug-induced autophagy by the use of rapamycin and chloroquine, as well as cells undergoing serum starvation. Although the mechanism of action of LysoTracker dyes is not fully understood, lysosomal mass increases during the autophagic process to enable the cell to produce autolysosomes. Given that LC3-II and LysoTracker are measuring different biological events in the autophagic process, they surprisingly both up-regulated during autophagic process. This approach shows that although LysoTracker dyes do not specifically label lysosomes or autophagosomes within the cell, they allow the simultaneous measurement of an autophagy related process and other live cell functions, which is not possible with the standard LC3-II antibody technique.

Autophagy in inflammation, infection, neurodegeneration and cancer

In its classical form, autophagy is an essential, homeostatic process by which cytoplasmic components are degraded in a double-membrane-bound autophagosome in response to starvation. Paradoxically, although autophagy is primarily a protective process for the cell, it can also play a role in cell death. The roles of autophagy bridge both the innate and adaptive immune systems and autophagic dysfunction is associated with inflammation, infection, neurodegeneration and cancer. In this review, we discuss the contribution of autophagy to inflammatory, infectious and neurodegenerative diseases, as well as cancer.

Increased autophagy in peripheral nerves may protect Wistar Ottawa Karlsburg W rats against neuropathy

OBJECTIVE

Wistar Ottawa Karlsburg W (RT1(u)) rats (WOKW) develop obesity, dyslipidemia, moderate hypertension, hyperinsulinemia and impaired glucose tolerance prone to induce peripheral neuropathy (PN). Autophagy has been shown to prevent neurodegeneration in the central and peripheral nervous system. We analyzed the potential protective role of autophagy in an established rat model in preventing PN.

METHODS

We examined electrophysiology (motor-and sensory/mixed afferent conduction velocities and the minimal F-wave latency) and morphology, including ultrathin sections, myelin sheath thickness (g-ratio) and immunohistochemical markers of autophagy and inflammation in the sciatic nerve of five-month-old, male WOKW as compared to Wistar derived, congenic LEW.1W control rats, characterized by the same major histocompatibility complex as WOKW rats (RT1(u)). Moreover, the expression of axonal and synaptic proteins (NF68, GAP43, MP0), autophagy- (Atg5, Atg7, LC3), and apoptosis (cleaved caspase-3)-related markers was measured using Western blot.

RESULTS

No abnormalities in nerve electrophysiology and morphology were found in WOKW compared to LEW.1W rats. However, autophagosomes were more frequently apparent in sciatic nerves of WOKW rats. In Western blot analyses no significant differences in expression of neuronal structural proteins were found, but autophagy markers were up-regulated in WOKW compared to LEW.1W sciatic nerves. Immunostaining revealed a greater infiltration of Iba1/ED-1-positive macrophages, CD-3-positive T-cells and LC3-expression in sciatic nerves of WOKW rats.

CONCLUSIONS

Our results indicate that WOKW rats show an up-regulated autophagy and a mild inflammatory response but do not develop overt neuropathy. We suggest that autophagy and inflammatory cells may exert a protective role in preventing neuropathy in this rat model of the metabolic syndrome but the mechanism of action is still unclear.

Induction of cytopathogenicity in human glioblastoma cells by chikungunya virus

Chikungunya virus (CHIKV), an arthritogenic old-world alphavirus, has been implicated in the central nervous system (CNS) infection in infants and elderly patients. Astrocytes are the major immune cells of the brain parenchyma that mediate inflammation. In the present study we found that a local isolate of CHIKV infect and activate U-87 MG cells, a glioblastoma cell line of human astrocyte origin. The infection kinetics were similar in infected U-87 MG cells and the human embryo kidney (HEK293) cells as indicated by immunofluorescence and plaque assays, 24h post-infection (p.i.). In infected U-87 MG cells, apoptosis was detectable from 48h p.i. evidenced by DNA fragmentation, PARP cleavage, loss of mitochondrial membrane potential, nuclear condensation and visible cytopathic effects in a dose and time-dependent manner. XBP1 mRNA splicing and eIF2α phosphorylation studies indicated the occurrence of endoplasmic reticulum stress in infected cells. In U-87 MG cells stably expressing a green fluorescent protein-tagged light chain-3 (GFP-LC3) protein, CHIKV infection showed increased autophagy response. The infection led to an enhanced expression of the mRNA transcripts of the pro-inflammatory cytokines IL-1β, TNF-α, IL-6 and CXCL9 within 24h p.i. Significant up-regulation of the proteins of RIG-I like receptor (RLR) pathway, such as RIG-I and TRAF-6, was observed indicating the activation of the cytoplasmic-cellular innate immune response. The overall results show that the U-87 MG cell line is a potential in vitro model for in depth study of these molecular pathways in response to CHIKV infection. The responses in these cells of CNS origin, which are inherently defective in Type I interferon response, could be analogous to that occurring in infants and very old patients who also have a compromised interferon-response. The results also point to the intriguing possibility of using this virus for studies to develop oncolytic virus therapy approaches against glioblastoma, a highly aggressive malignancy.

Activation of Autophagy Pathway Suppresses the Expression of iNOS, IL6 and Cell Death of LPS-Stimulated Microglia Cells

Microglia play a role in maintaining and resolving brain tissue homeostasis. In pathological conditions, microglia release pro-inflammatory cytokines and cytotoxic factors, which aggravate the progression of neurodegenerative diseases. Autophagy pathway might be involved in the production of pro-inflammatory cytokines and cytotoxic factors in microglia, though details of the mechanism remain largely unknown. In the present study, we examined the role of the autophagy pathway in activated BV2 microglia cells. In BV2 cells, rapamycin treatment activated the formation of anti-LC3-labeled autophagosomes, whereas the ATG5 depletion using siRNA-ATG5 prevented the formation of LC3-labeled autophagosomes, indicating that BV2 cells exhibit an active classical autophagy system. When treated with LPS, BV2 cells expressed an increase of anti-LC3-labeled dots. The levels of LC3-labeled dots were not suppressed, instead tended to be enhanced, by the inhibition of the autophagy pathway with siRNA-ATG5 or wortmannin, suggesting that LPS-induced LC3-labeled dots in nature were distinct from the typical autophagosomes. The levels of LPS-induced expression of iNOS and IL6 were suppressed by treatment with rapamycin, and conversely, their expressions were enhanced by siRNA-ATG5 treatment. Moreover, the activation of the autophagy pathway using rapamycin inhibited cell death of LPS-stimulated microglia. These results suggest that although microglia possess a typical autophagy pathway, the glial cells express a non-typical autophagy pathway in response to LPS, and the activation of the autophagy pathway suppresses the expression of iNOS and IL6, and the cell death of LPS-stimulated microglia.

Inflammatory cytokines protect retinal pigment epithelial cells from oxidative stress-induced death

Purpose

To investigate the effects of inflammatory factors and oxidative stress on cell survival of the human retinal pigment epithelial (RPE) cell line, ARPE-19.

Methods

Confluent RPE cells were treated with peripheral blood mononuclear cells-conditioned medium (PCM), H₂O₂, NaIO₃, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, or combinations of these. Cell viability was determined by viability assays and by light microscopy. Effector molecules of cell death were investigated by immunofluorescence microscopy and flow cytometry. Microarrays were performed to screen for differential expression of anti-oxidative enzymes, and protein expression was validated by immunoblotting.

Results

Viability of RPE cells was reduced by exposure to inflammatory agents (PCM, IFNγ+/-TNFα) or to oxidative agents (H₂O₂ or NaIO₃). Unexpectedly, cells treated with either H₂O₂ or NaIO₃ were partially protected from cell death by the addition of PCM. This protection was conferred, at least in part, by IFNγ and TNFα. Cell death induced by H₂O₂ or NaIO₃ was preceded by mitochondrial dysfunction and by p62 upregulation, both of which were attenuated by PCM and/or by IFNγ+TNFα. RPE cells co-cultured with activated T cells, or treated with cytokines showed increased expression of anti-oxidative genes, with upregulation of superoxide dismutase 2 protein following PCM treatment.

Conclusion

Oxidative stress-induced cell death was reduced by concomitant inflammatory stress. This is likely due to the cytokine-mediated induction of the anti-oxidative stress response, upregulating protective anti-oxidant pathway(s). These findings suggest caution for the clinical use of anti-inflammatory agents in the management of immune-associated eye diseases such as age-related macular degeneration.

Toxoplasmosis and Polygenic Disease Susceptibility Genes: Extensive Toxoplasma gondii Host/Pathogen Interactome Enrichment in Nine Psychiatric or Neurological Disorders

Toxoplasma gondii is not only implicated in schizophrenia and related disorders, but also in Alzheimer's or Parkinson's disease, cancer, cardiac myopathies, and autoimmune disorders. During its life cycle, the pathogen interacts with ~3000 host genes or proteins. Susceptibility genes for multiple sclerosis, Alzheimer's disease, schizophrenia, bipolar disorder, depression, childhood obesity, Parkinson's disease, attention deficit hyperactivity disorder (P  from  8.01E - 05  (ADHD)  to  1.22E - 71) (multiple sclerosis), and autism (P = 0.013), but not anorexia or chronic fatigue are highly enriched in the human arm of this interactome and 18 (ADHD) to 33% (MS) of the susceptibility genes relate to it. The signalling pathways involved in the susceptibility gene/interactome overlaps are relatively specific and relevant to each disease suggesting a means whereby susceptibility genes could orient the attentions of a single pathogen towards disruption of the specific pathways that together contribute (positively or negatively) to the endophenotypes of different diseases. Conditional protein knockdown, orchestrated by T. gondii proteins or antibodies binding to those of the host (pathogen derived autoimmunity) and metabolite exchange, may contribute to this disruption. Susceptibility genes may thus be related to the causes and influencers of disease, rather than (and as well as) to the disease itself.

Functional expression of SCL/TAL1 interrupting locus (Stil) protects retinal dopaminergic cells from neurotoxin-induced degeneration

We previously isolated a dominant mutation, night blindness b (nbb), which causes a late onset of retinal dopaminergic cell degeneration in zebrafish. In this study, we cloned the zebrafish nbb locus. Sequencing results revealed that nbb is a homolog of the vertebrate SCL/TAL1 interrupting locus (Stil). The Stil gene has been shown to play important roles in the regulation of vertebrate embryonic neural development and human cancer cell proliferation. In this study, we demonstrate that functional expression of Stil is also required for neural survival. In zebrafish, decreased expression of Stil resulted in increased toxic susceptibility of retinal dopaminergic cells to 6-hydroxydopamine. Increases in Stil-mediated Shh signaling transduction (i.e. by knocking down the Shh repressor Sufu) prevented dopaminergic cell death induced by neurotoxic insult. The data suggest that the oncogene Stil also plays important roles in neural protection.

A double-edged sword with therapeutic potential: an updated role of autophagy in ischemic cerebral injury

Cerebral ischemia is a severe outcome that could cause cognitive and motor dysfunction, neurodegenerative diseases and even acute death. Although the existence of autophagy in cerebral ischemia is undisputable, the consensus has not yet been reached regarding the exact functions and influence of autophagy in cerebral ischemia. Whether the activation of autophagy is beneficial or harmful in cerebral ischemia injury largely depends on the balance between the burden of intracellular substrate targeted for autophagy and the capacity of the cellular autophagic machinery. Furthermore, the mechanisms underlying the autophagy in cerebral ischemia are far from clear yet. This brief review focuses on not only the current understanding of biological effects of autophagy, but also the therapeutic potentials of autophagy in ischemic stroke. There are disputes over the exact role of autophagy in cerebral ischemia. Application of chemical autophagy inhibitor (e.g., 3-methyladenine) or inducer (e.g., rapamycin) in vitro and in vivo was reported to protect or harm neuronal cell. Knockdown of autophagic protein, such as Beclin 1, was also reported to modulate the cerebral ischemia-induced injury. Moreover, autophagy inhibitor abolished the neuroprotection of ischemic preconditioning, implying a neuroprotective effect of autophagy. To clarify these issues on autophagy in cerebral ischemia, future investigations are warranted.